introduction Index Helpful Information Dwyer Instruments, Inc.

introduction Index Helpful Information Dwyer Instruments, Inc.
pg 1
12/10/03
6:01 PM
Page 1
introduction
Index
Helpful Information
Glossary of Terms
Products from Dwyer
New Products
Dwyer Instruments, Inc.
Engineering and Applications
Handbook
1–4
4
5–7
8
Pressure
Measurement
Control
To help engineers solve design, manufacturing and physical
plant problems, Dwyer Instruments, Inc. has developed this
Engineering and Product Applications handbook. When such
problems involve the measurement or control of gage or differential pressure, temperature, level or flow, chances are there is
a Dwyer Instruments product that can provide the solution.
Reviewing the applications illustrated in this handbook may trigger an idea for a new approach to solving your engineering
problems. For design engineers, these applications may also
suggest ways to solve a customer problem and become the
basis for a new product development.
The information contained in this handbook may also suggest a
more reliable, convenient and lower cost approach when
reworking an existing product or system design. In many cases
the application suggestions may cut costs by increasing efficiency through continuous control of systems and processes.
The Engineering and Applications handbook also illustrates how
engineers and technicians find applications for Dwyer controls
and gages on a wide range of products serving a broad spectrum of industries and markets.
The Dwyer Instruments, Inc. full-line catalog and its websites
deliver the convenience and assistance you want from an instrumentation company. Our catalogs are available to you free of
charge via telephone, fax or websites. In addition, our websites
contain installation and operating manuals on our products that
are easily downloadable to your computer or printer.
Total customer service is our goal.
9 – 12
12 – 24
Flow/Air Velocity
Air/Gas
Liquid
24 – 33
34 – 40
Level
Liquid
Process
Control
40 – 43, 45
41
43 – 45
Temperature
Control
45 – 49
Valves
Control
Process
48 – 49
50
Miscellaneous
Process
50
Analyze/Measure/Control 51
Reference
Important Note:
52
Instruments, Inc., nor the Mercoid, Proximity, Love Controls or
W.E. Anderson Divisions, shall be liable for loss, damage, or
expense directly or indirectly arising from the use of any product described herein. In no event shall any of these Companies
be liable for direct, indirect, special, or consequential damages.
©
Copyright 2003 Dwyer Instruments, Inc. No part of this handbook may be reproduced in any form without the express written consent of Dwyer Instruments, Inc.
The gage and control hook-ups and sketches, and other application information shown in this Handbook are generalized and
abbreviated to present the basic application idea only and no
proprietary information has been revealed.
We believe this application information to be reliable, but is
intended for use by persons, at their own discretion, having
technical skill and knowledge of the business. Neither Dwyer
1
obc/ofc
12/11/03
8:10 AM
Page 1
DWYER INSTRUMENTS, INC.
P.O. Box 373
Michigan City, IN 46361-9986
Return Service Requested
dom.ifc/ibc
12/11/03
8:19 AM
Page 1
Pressure Conversion Chart
Founded in 1931, Dwyer Instruments, Inc. produces a broad range of competitively priced
precision instruments for measuring, transmitting and controlling pressure, temperature
level, flow and related applications.
Many of these instruments are widely know by their individual brand names, such as
Magnehelic® and Spirahelic® pressure gages, Photohelic® switch/gages, Rate-Master® and
Visi-Float® flowmeters and Hi-Flow® valves. Divisions include well-known brand names such
as Mercoid, W.E. Anderson, Proximity Controls and Love Controls.
Headquartered in Michigan City, Indiana, the company has four more Indiana manufacturing
facilities, as well as manufacturing facilities in Anaheim, California; Fergus Falls, Minnesota;
Kansas City, Missouri; and Naguabo, Puerto Rico.
In addition to making and selling quality precision instruments, Dwyer is committed to a standard of customer service – including competitive prices and knowledgeable, courteous technical support – that generates and sustains long-term relationships.
Customer Service
Fast, friendly customer service professionals are available to
process and provide assistance with your order – whether it
is by phone, fax, e-mail or through our website.
Technical Support
Have an application question? Our technical support
professionals are trained to provide you with the
answers you need.
Prompt Shipments
After you place your order, Dwyer’s dedicated
shipping staff packs and ships your order promptly
and completely –within 24 hours on most in-stock
items.
Website
Dwyer Instrument’s website delivers the convenience
you want. Go to www.dwyer-inst.com for the most
complete ordering and product support information at
your fingertips – anytime, day or night. Installation and
operating manuals are available on products that are
easily downloadable to your computer or printer.
Total customer service the way you need it.
Dwyer Instruments, Inc.
accepts Visa® and
Mastercard®.
Address:
Dwyer Instruments, Inc.
102 Indiana Highway 212
P.O. Box 373
Michigan City, IN 46361 U.S.A.
e-mail:
General: [email protected]
Literature: [email protected]
Technical: [email protected]m
Quotes: [email protected]
website:
http://www.dwyer-inst.com
http://www.love-controls.com
http://dwyer-inst.com/retail
http://proximitycontrols.com
Telephone:
(800) 872-9141
(219) 879-8000
Fax:
(219) 872-9057
in/H2O
P.S.I.
in/Hg
mm/H2O mm/Hg
.1
.2
.4
.6
.8
1.0
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
.0036
.0072
.0144
.0216
.0289
.0361
.0722
.1083
.1444
.1804
.2165
.2526
.2887
.3248
.3609
.3970
.4331
.4692
.5053
.5414
.5774
.6136
.6496
.6857
.7218
.7579
.7940
.8301
.8662
.9023
.9384
.9745
1.010
1.047
1.083
1.119
1.155
1.191
1.227
1.263
1.299
1.335
1.371
1.408
1.444
1.480
1.516
1.552
1.588
1.624
1.660
1.696
1.732
1.768
1.804
1.841
1.877
1.913
1.949
1.985
2.021
2.057
2.093
2.129
2.165
2.202
2.238
2.274
2.310
2.346
2.382
2.418
2.454
2.490
2.526
2.562
2.598
2.635
2.671
2.707
2.743
2.779
2.815
2.851
2.887
2.923
2.959
2.996
3.032
3.068
3.104
3.140
3.176
3.212
3.248
3.284
3.320
3.356
3.392
3.429
3.456
3.501
3.537
3.573
3.609
.0073
.0146
.0293
.0440
.0588
.0735
.1470
.2205
.2940
.3673
.4408
.5143
.5878
.6613
.7348
.8083
.8818
.9553
1.029
1.102
1.176
1.249
1.322
1.396
1.470
1.543
1.616
1.690
1.764
1.837
1.910
1.984
2.056
2.132
2.205
2.278
2.352
2.425
2.498
2.571
2.645
2.718
2.791
2.876
2.940
3.013
3.086
3.160
3.233
3.306
3.378
3.453
3.526
3.600
3.673
3.748
3.822
3.895
3.968
4.041
4.115
4.188
4.261
4.335
4.408
4.483
4.556
4.630
4.703
4.776
4.850
4.923
4.996
5.070
5.143
5.216
5.290
5.365
5.438
5.511
5.585
5.658
5.731
5.805
5.878
5.951
6.024
6.100
6.173
6.246
6.320
6.393
6.466
6.450
6.613
6.686
6.760
6.833
6.906
6.981
7.055
7.128
7.201
7.275
7.348
2.534
5.067
10.13
15.20
20.34
25.41
50.81
76.22
101.62
127.0
152.4
177.8
203.2
228.6
254.0
279.4
304.8
330.2
355.6
381.0
406.4
431.8
457.2
482.6
508.0
533.4
558.8
584.2
609.6
635.0
660.4
685.8
710.8
736.8
762.2
787.5
812.8
836.2
863.5
888.9
914.2
939.5
964.9
990.9
1016
1042
1067
1092
1118
1143
1168
1194
1219
1244
1270
1296
1321
1346
1372
1397
1422
1448
1473
1498
1524
1550
1575
1600
1626
1651
1676
1702
1727
1752
1778
1803
1828
1854
1880
1905
1930
1956
1981
2006
2032
2057
2082
2108
2134
2159
2184
2210
2265
2260
2286
2311
2336
2362
2387
2413
2438
2464
2489
2514
2540
.1863
.3726
.7452
1.118
1.496
1.868
3.736
5.604
7.472
9.335
11.203
13.072
14.940
16.808
18.676
20.544
22.412
24.280
26.148
28.016
29.879
31.752
33.616
35.484
37.352
39.22
41.09
42.96
44.82
46.69
48.56
50.43
52.26
54.18
56.04
57.91
59.77
61.63
63.49
65.36
67.22
69.08
70.95
72.86
74.72
76.59
78.45
80.31
82.18
84.04
85.90
87.76
89.63
91.49
93.35
95.27
97.13
98.99
100.8
102.7
104.6
106.4
108.3
110.2
112.0
113.9
115.8
117.7
119.5
121.4
123.3
125.1
127.0
128.8
130.7
132.6
134.4
136.4
138.2
140.1
141.9
143.8
145.7
147.5
149.4
151.2
153.1
155.0
156.9
158.8
160.6
162.5
164.4
166.2
168.1
169.9
171.8
173.7
175.5
177.4
179.3
181.2
183.0
184.9
186.8
kg/cm2
bar
mbar
Pa
kPa
P.S.I.
in/H2O
in/Hg
mm/H2O mm/Hg
kg/cm2
.0002
.0005
.0010
.0015
.0020
.0025
.0051
.0076
.0102
.0127
.0152
.0178
.0203
.0228
.0254
.0279
.0304
.0330
.0355
.0381
.0406
.0431
.0457
.0482
.0507
.0533
.0558
.0584
.0609
.0634
.0660
.0685
.0710
.0736
.0761
.0787
.0812
.0837
.0862
.0888
.0913
.0938
.0964
.0990
.1015
.1040
.1066
.1091
.1116
.1142
.1167
.1192
.1218
.1243
.1268
.1294
.1320
.1345
.1370
.1395
.1421
.1146
.1471
.1497
.1522
.1548
.1573
.1599
.1624
.1649
.1674
.1700
.1725
.1750
.1776
.1801
.1826
.1852
.1878
.1903
.1928
.1954
.1979
.2004
.2030
.2055
.2080
.2106
.2131
.2157
.2182
.2207
.2233
.2258
.2283
.2309
.2334
.2359
.2384
.2410
.2436
.2461
.2486
.2512
.2537
.0002
.0005
.0010
.0015
.0020
.0025
.0050
.0075
.0099
.0124
.0149
.0174
.0199
.0224
.0249
.0274
.0299
.0324
.0348
.0373
.0398
.0423
.0448
.0473
.0498
.0523
.0547
.0572
.0597
.0622
.0647
.0672
.0696
.0722
.0747
.0772
.0796
.0821
.0846
.0871
.0896
.0920
.0945
.0971
.0996
.1020
.1045
.1070
.1095
.1120
.1144
.1169
.1194
.1219
.1244
.1269
.1294
.1319
.1344
.1369
.1393
.1418
.1443
.1468
.1493
.1518
.1543
.1568
.1593
.1618
.1642
.1667
.1692
.1717
.1742
.1766
.1791
.1817
.1842
.1866
.1891
.1916
.1941
.1966
.1991
.2015
.2040
.2066
.2091
.2115
.2140
.2165
.2190
.2215
.2239
.2264
.2289
.2314
.2339
.2364
.2389
.2414
.2439
.2464
.2488
.2482
.4964
.9928
1.489
1.992
2.489
4.978
7.467
9.956
12.44
14.93
17.42
19.90
22.39
24.88
27.37
29.86
32.35
34.84
37.33
39.81
42.31
44.79
47.28
49.77
52.26
54.74
57.23
59.72
62.21
64.70
67.19
69.64
72.19
74.67
77.15
79.63
82.12
84.60
87.08
89.56
92.04
94.53
97.08
99.56
102.0
104.5
107.0
109.5
112.0
114.5
116.9
119.4
121.9
124.4
126.9
129.4
131.9
134.4
136.9
139.3
141.8
144.3
146.8
149.3
151.8
154.3
156.8
159.3
161.8
164.2
166.7
169.2
171.7
174.2
176.6
179.1
181.7
184.2
186.6
189.1
191.6
194.1
196.6
199.1
201.5
204.0
206.6
209.1
211.5
214.0
216.5
219.0
221.5
223.9
226.4
228.9
231.4
233.9
236.4
238.9
241.4
243.9
246.4
248.8
24.82
49.64
99.28
148.9
199.2
248.9
497.8
746.7
995.6
1244
1493
1742
1990
2239
2488
2737
2986
3235
3484
3733
3981
4231
4479
4728
4977
5226
5474
5723
5972
6221
6470
6719
6964
7219
7467
7715
7963
8212
8460
8708
8956
9204
9453
9708
9956
10204
10452
10701
10949
11197
11445
11694
11942
12190
12438
12693
12941
13190
13438
13686
13934
14182
14431
14679
14927
15182
15430
15679
15927
16175
16423
16672
16920
17168
17416
17664
17912
18168
18416
18664
18912
19160
19409
19657
19905
20153
20402
20657
20905
21153
21401
21650
21898
22146
22394
22642
22890
23139
23387
23642
23890
24138
24387
24635
24883
.0248
.0496
.0993
.1489
.1992
.2489
.4978
.7476
.9956
1.244
1.493
1.742
1.990
2.239
2.488
2.737
2.986
3.235
3.484
3.733
3.981
4.231
4.479
4.728
4.977
5.226
5.474
5.723
5.972
6.221
6.470
6.719
6.964
7.219
7.467
7.715
7.963
8.212
8.460
8.708
8.956
9.204
9.453
9.708
9.956
10.20
10.45
10.70
10.95
11.20
11.44
11.69
11.94
12.19
12.44
12.69
12.94
13.19
13.44
13.69
13.93
14.18
14.43
14.68
14.93
15.18
15.43
15.68
15.93
16.18
16.42
16.67
16.92
17.17
17.42
17.66
17.91
18.17
18.42
18.66
18.91
19.16
19.41
19.66
19.90
20.15
20.40
20.66
20.90
21.15
21.40
21.65
21.90
22.15
22.39
22.64
22.89
23.14
23.39
23.64
23.89
24.14
24.39
24.64
24.88
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
6.0
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
7.0
7.1
7.2
7.3
7.4
7.5
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0
9.2
9.4
9.6
9.8
10.0
11.0
12.0
13.0
14.0
14.7
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
27.71
30.45
33.22
35.98
38.75
41.52
44.29
47.06
49.82
52.59
55.36
58.13
60.90
63.67
66.43
69.20
71.97
74.74
77.51
80.27
83.04
85.81
88.58
91.35
94.11
96.88
99.65
102.4
105.2
108.0
110.7
113.5
116.3
119.0
121.8
124.6
127.3
130.1
132.9
135.6
138.4
141.2
143.9
146.7
149.5
152.2
155.0
157.8
160.5
163.3
166.1
168.8
171.6
174.4
177.2
179.9
182.7
185.5
188.2
191.0
193.8
196.5
199.3
202.1
204.8
207.6
210.4
215.9
221.4
227.0
232.5
238.0
243.6
249.1
254.7
260.2
265.7
271.3
276.8
304.5
332.2
359.8
387.5
406.9
415.2
442.9
470.6
498.2
525.9
553.6
581.3
609.0
636.7
664.3
692.0
2.036
2.240
2.443
2.647
2.850
3.054
3.258
3.461
3.665
3.686
4.072
4.276
4.479
4.683
4.886
5.090
5.294
5.497
5.701
5.904
6.108
6.312
6.515
6.719
6.922
7.126
7.330
7.535
7.737
7.940
8.144
8.348
8.551
8.775
8.958
9.162
9.366
9.569
9.773
9.976
10.18
10.38
10.59
10.79
10.99
11.20
11.40
11.60
11.81
12.01
12.22
12.42
12.62
12.83
13.03
13.23
13.44
13.64
13.84
14.05
14.25
14.46
14.66
14.86
15.07
15.27
15.47
15.88
16.29
16.70
17.10
17.51
17.92
18.32
18.73
19.14
19.54
19.95
20.36
22.40
24.43
26.47
28.50
29.93
30.54
32.58
34.61
36.65
36.68
40.72
42.76
44.79
46.83
48.86
50.90
703.1
773.4
843.7
914.0
984.3
1055
1125
1195
1266
1336
1406
1476
1547
1617
1687
1758
1828
1898
1969
2039
2109
2180
2250
2320
2390
2461
2531
2601
2672
2742
2812
2883
2953
3023
3094
2164
3234
3304
3375
3445
3515
3586
3656
3726
3797
3876
3973
4008
4078
4148
4218
4289
4359
4429
4500
4570
4640
4711
4781
4851
4922
4992
5062
5132
5203
5273
5343
5484
5625
5765
5906
6047
6187
6328
6468
6609
6750
6890
7031
7734
8437
9140
9843
10340
10550
11250
11950
12660
13360
14060
14770
15470
16170
16870
17580
.0703
.0773
.0844
.0914
.0984
.1055
.1125
.1195
.1266
.1336
.1406
.1476
.1547
.1617
.1687
.1758
.1828
.1898
.1968
.2039
.2109
.2180
.2250
.2320
.2390
.2461
.2531
.2601
.2672
.2742
.2812
.2883
.2953
.3023
.3094
.3164
.3234
.3304
.3375
.3445
.3515
.3586
.3656
.3726
.3797
.3867
.3937
.4007
.4078
.4148
.4218
.4289
.4359
.4429
.4500
.4570
.4640
.4710
.4781
.4851
.4921
.4992
.5062
.5132
.5203
.5273
.5343
.5484
.5625
.5765
.5906
.6046
.6187
.6328
.6468
.6609
.6749
.6890
.7031
.7734
.8437
.9140
.9843
1.033
1.055
1.125
1.195
1.265
1.336
1.406
1.476
1.547
1.617
1.687
1.758
CONVERSION
FACTORS
NOTE:
CONVERSION FACTORS
ROUNDED
51.75
56.89
62.06
67.23
72.40
77.57
82.74
87.92
93.09
98.26
103.4
108.6
113.8
118.9
124.1
129.3
134.5
139.6
144.8
150.0
155.1
160.3
165.5
170.7
175.8
181.0
186.2
191.3
196.5
201.7
206.9
212.0
217.2
222.4
227.5
232.7
237.9
243.1
248.2
253.4
258.6
263.7
268.9
274.1
279.3
284.4
289.6
294.8
299.9
305.1
310.3
315.5
320.6
325.8
331.0
336.1
341.3
346.5
351.7
356.8
362.0
367.2
372.3
377.5
382.7
387.9
393.0
403.4
413.7
424.1
434.4
444.7
455.1
465.4
475.8
486.1
496.5
506.8
517.1
568.9
620.6
672.3
724.0
760.2
775.7
827.4
879.1
930.9
982.6
1034
1086
1138
1189
1241
1293
P.S.I.
P.S.I.
P.S.I.
P.S.I.
P.S.I.
x
x
x
x
x
27.71
2.036
703.1
51.75
.0703
=
=
=
=
=
bar
mbar
.0689
.0758
.0827
.0896
.0965
.1034
.1103
.1172
.1241
.1310
.1379
.1448
.1517
.1586
.1655
.1724
.1793
.1862
.1930
.1999
.2068
.2137
.2206
.2275
.2344
.2413
.2482
.2551
.2620
.2689
.2758
.2827
.2896
.2965
.3034
.3103
.3172
.3240
.3310
.3378
.3447
.3516
.3585
.3654
.3723
.3792
.3861
.3930
.3999
.4068
.4137
.4206
.4275
.4344
.4413
.4482
.4550
.4619
.4688
.4757
.4826
.4895
.4964
.5033
.5102
.5171
.5240
.5378
.5516
.5654
.5792
.5929
.6067
.6205
.6343
.6481
.6619
.6757
.6895
.7584
.8274
.8963
.9652
1.014
1.034
1.103
1.172
1.241
1.310
1.379
1.448
1.517
1.586
1.655
1.724
68.95
75.84
82.74
89.63
96.52
103.4
110.3
117.2
124.1
131.0
137.9
144.8
151.7
158.6
165.5
172.4
179.3
186.2
193.0
199.9
206.8
213.7
220.6
227.5
234.4
241.3
248.2
255.1
262.0
268.9
275.8
282.7
289.6
296.5
303.4
310.3
317.2
324.0
331.0
337.8
344.7
351.6
358.5
365.4
372.3
379.2
386.1
393.0
399.9
406.8
413.7
420.6
427.5
434.4
441.3
448.2
455.0
461.9
468.8
475.7
482.6
489.5
496.4
503.3
510.2
517.1
524.0
537.8
551.6
565.4
579.2
592.9
606.7
620.5
634.3
648.1
661.9
675.7
689.5
758.4
827.4
896.3
965.2
1014
1034
1103
1172
1241
1310
1379
1448
1517
1586
1655
1724
in. H2O
in. Hg
mm/H2O
mm/Hg
kg/cm2
P.S.I.
P.S.I.
P.S.I.
P.S.I.
Pa
6895
7584
8274
8963
9652
10340
11030
11720
12410
13100
13790
14480
15170
15860
16550
17240
17930
18620
19300
19990
20680
21370
22060
22750
23440
24130
24820
25510
26200
26890
27580
28270
28960
29650
30338
31030
31720
32400
33100
33780
34470
35160
35850
36540
37230
37920
38610
39300
39990
40680
41370
42060
42750
43440
44130
44820
45500
46190
46880
47570
48260
48950
49640
50330
51020
51710
52400
53780
55160
56540
57920
59290
60670
62050
63430
64810
66190
67570
68950
75840
82740
98630
96520
101400
103400
110300
117200
124100
131000
137900
144800
151700
158600
165500
172400
x
x
x
x
kPa
6.895
7.584
8.274
8.963
9.652
10.34
11.03
11.72
12.41
13.10
13.79
14.48
15.17
15.86
16.55
17.24
17.93
18.62
19.30
19.99
20.68
21.37
22.06
22.75
23.44
24.13
24.82
25.51
26.20
26.89
27.58
28.27
28.96
29.65
30.34
31.03
31.72
32.40
33.10
33.78
34.47
35.16
35.85
36.54
37.23
37.92
38.61
39.30
39.99
40.68
41.37
42.06
42.75
43.44
44.13
44.82
45.50
46.19
46.88
47.57
48.26
48.95
49.64
50.33
51.02
51.71
52.40
53.78
55.16
56.54
57.92
59.29
60.67
62.05
63.43
64.81
66.19
67.57
68.95
75.84
82.74
89.63
96.52
101.4
103.4
110.3
117.2
124.1
131.0
137.9
144.8
151.7
158.6
165.5
172.4
.0689 = bar
68.95 = mbar
6895 = Pa
6.895 = kPa
pg 2
12/10/03
6:03 PM
Page 1
helpful information
However, AC arcing associated with resistive loads is self-extinguishing, as the voltage goes to zero at a rate equal to the line frequency.
Inductive AC loads also require significant derating of the switch. This
is due to the high voltage surge created when the circuit is broken,
resulting in heavy momentary arcing which can destroy the switch
contacts.
The best solution to control DC or inductive AC loads with Dwyer differential pressure switches is the use of an appropriate interface
device, such as a mechanical relay or solid-state switching unit.
In "dry" circuit applications, where extremely low or no current flow is
involved, specify the gold contact option for the microswitch to ensure
reliable long-term operation.
Note these important design precautions:
As you start to design a new product or system that includes Dwyer
Instruments components, you undoubtedly plan to achieve maximum
performance, reliability and safety. A thorough knowledge of the characteristics of the Dwyer products included will help ensure the most
successful result.
The following recommendations are based on years of field experience.
They should prove invaluable to you in specifying the most suitable and
efficient components for your application.
Pressure
The specified pressure ratings for Dwyer differential pressure gages,
differential pressure switches, manometers, and flowmeters must be
carefully observed. The Dwyer catalog lists options available for higherthan-standard pressure operation of the Dwyer Magnehelic® differential
pressure gage and Photohelic® differential pressure switch/gage. In
addition, small safety relief valves are available for these gages. The
valves can be teed directly into the sensing line.
Pressure relief valves with adequate venting capacity should be used in
any system if the supply is capable of delivering the air, gas, or other
fluid at pressures greater than the system capability. If the system gas
or fluid is noxious or toxic, be sure to dispose of this material properly
by piping the pressure relief valve vent to a safe area.
When pressure regulators are used to reduce high-pressure air or gas
for use in low-pressure systems, pressure relief valves should be
installed on the low-pressure side of the regulator to protect the system
in case of regulator failure or operator error. If pressure relief valves are
not provided, pressure supply equipment should be selected with maximum pressure capability less than that which is safe for all components in the system.
Compatibility
It is important to ensure that the media coming in contact with a Dwyer
control or gage be compatible with the materials of the wetted parts.
This is necessary to prevent eventual failure of the control or gage or
the contamination of the media itself. The various materials used as
components of Dwyer controls and gages are specified in our catalogs.
Various optional elastomers, metals, and plastics are available to meet
specific customer requirements. In addition, special cleaning of all
Dwyer controls and gages is required for oxygen service (except the
Dwyer Photohelic® differential pressure switch/gage, which is not suitable for oxygen service).
We have data available on a wide range of media regarding compatibility with various stock or special products. Visit our website or call your
Dwyer sales office for assistance in matters of material compatibility.
Reliability
Ideally, all pneumatic instrument systems should work with clean filtered air or gas which is non-toxic and dried to a dew point well below
any ambient temperature in which the system will operate. Since this
is not always practical, it is important to remember that, with few
exceptions, air contains a substantial quantity of dirt and moisture.
Over a period of time, the dirt accumulates until it plugs static tips, pitot
tubes, sensing lines, even the gage and switch itself.
Changes in temperature in the sensing system, particularly in outdoor
applications, may cause moisture in the system air or gas to condense.
The accumulated water then creates problems in the gage, control, or
sensing line. Such accumulations can produce corrosion, damage due
to freezing, or simple blockage while in the liquid state.
Sensing and control systems are particularly susceptible to problems
when operating in dust laden air, corrosive and wet media such as flue
gases, and the moisture laden air associated with scrubbers and dryers.
In the case of dust laden air or dirty liquids, sensing lines (and vented
gage or control ports in ambient industrial conditions) should be
equipped with filters having adequate surface area. The filters, as well as
static tips or pitot tubes, should be inspected and cleaned frequently.
To protect against condensation, water separators, or drop legs should
be installed in the sensing system at the low points where condensation
will accumulate. The drop leg need only be made of a pipe section teed
into the line and extending vertically downward from the desired location with a valve at the bottom to drain the water periodically. Using a
large diameter pipe for the drop leg increases storage capacity and minimizes the number of times it must be drained.
Corrosive gases are often both dirty and moist. They may require both
of the preceding precautions plus careful attention to compatibility with
the wetted parts of the control or gage.
Temperature
Because of the variety of elastomers and fluids used in Dwyer differential pressure controls and gages, specified operating temperature
ranges for these products will vary. Pay particular attention to the temperature specification in the Dwyer catalog or installation and operating
manual when you consider an application at high or low temperature.
Options are available in some instances to provide for operation at lower
than the specified minimum temperature, but such options may limit
the ranges available and reduce the permissible maximum operating
pressure.
If you specify manometers using water as the indicating fluid, take care
to ensure that these manometers are never used in ambient temperatures below freezing. Call your nearest Dwyer sales office for information if you need special products and ratings to meet temperature and
pressure conditions beyond the specifications of standard Dwyer products.
Electrical
To obtain maximum operating life, the electrical specifications for
Dwyer controls and gages must be carefully observed. In order to provide specified performance, particularly in the low ranges, Dwyer differential pressure switches utilize a microswitch with a small contact gap
and low spring rate to minimize operating force and movement.
Because of the small contact gap, the maximum ratings are limited to
resistive AC loads. The microswitch does not have a DC rating, as the
gap can maintain a DC arc when the contact is broken under load even
at very low currents.
2
pg 3
12/10/03
6:05 PM
Page 1
helpful information
Magnehelic® gage as an air-flow monitor in a ventilation system, favor
measuring total differential pressure across the blower versus sensing
only static, velocity, or even total pressure on just one side or the
other.
When it is necessary to repeatedly pressurize and depressurize a system, you can minimize or eliminate unwanted switch closures or
annoying full-scale gage pointer deflection by placing suitable restrictors in the line on both sides or in some cases, only the low-volume
side of the switch or gage.
When using Dwyer Magnehelic® differential pressure gages or
Photohelic® differential pressure switch/gages in sensitive leak test
systems, it is best to specify our "leak test option" when ordering the
gage itself. This will reduce erroneous readings due to normal slight
leakage in the instrument itself.
Although it is not possible to completely eliminate leakage in instruments with elastomer diaphragms, our special "leak test option" procedures and extra care will usually reduce the leakage to an acceptable
level.
To minimize the potential for gage error due to a shift in the zero point
reading, it is good practice to install two-way vent valves in both ports
of a differential pressure gage. These valves permit closing off the
sensing lines in an operating system while simultaneously venting
both ports of the gage to the atmosphere to permit checking the zero
setting or re-zeroing as necessary.
Your nearest Dwyer field sales engineer will be glad to review your
application with you. He/she may help ensure maximum performance
of the Dwyer control or gage specified.
It is most important to approach pneumatic systems design with the
understanding that, despite careful design and safeguards, everything
will eventually become dirty, wet, or corroded. Thus a good preventive
maintenance plan is the key to maximum reliability.
Where the control or gage will be installed in a harsh environment, the
added protection of a suitable housing is highly desirable. If a control
or gage must be mounted outside, exposed to the elements, it should
be protected as much as possible from direct exposure to the sun, rain,
wind, heat, and cold. Weatherproof housings are available for most
Dwyer controls and gages and certain models are inherently weatherproof.
A tropicalization treatment can be ordered for Dwyer differential pressure switches to be installed in hot, humid environments.
Although Dwyer sales personnel can advise you regarding materials
compatibility and the proper application of Dwyer instruments and
controls, system design is beyond the scope of their activities and
the coverage of Dwyer's product liability insurance policy. For
aspects of system design beyond the capability of the designer, we
suggest retaining the services of a consulting engineer.
Safety
All of the above precautions are basic to the safe operation of any system employing pneumatic controls and gages. Particular emphasis
should be placed on these precautions when systems are operating
near the maximum rated pressure for the components, or when the
gas or fluid in the system is noxious, toxic, or combustible, or where
the system environment itself is hazardous due to explosive fumes or
gases.
Dwyer offers various options and models to provide controls and
gages capable of safe operation in an explosive environment. For
example, you can order optional non-removable valve stems for Dwyer
flowmeters to prevent the accidental release of pressurized or hazardous materials.
Before using combustible gases to operate Dwyer differential pressure
gages, discuss your plan with a sales engineer. Potential compatibility
and leakage problems may require a special modification for your
application. These gages do not have built-in restrictors normally
employed in combustible gas equipment.
Perhaps most important of all in designing a safe system is to realize
that even the most reliable component, properly specified and
installed, can and will fail eventually. Therefore, we recommend that
systems be designed to fail-safe, i.e., the system will shut down or the
process will stop if any critical component fails.
The system should be designed to anticipate failure due to loss of
pneumatic pressure, loss of electrical power or any other possibility of
failure related to the installation. Where positive operation is essential,
back-up or redundant controls and power should be provided.
Additional Design Precautions for Mercoid Products
In general, the preceding design precautions also apply for Mercoid
pressure, temperature, and level controls. However, as Mercoid products can be applied to a wider range of media under higher temperatures and pressures, often in more hostile environments, the following added design precautions should be considered.
As in any control application, the switch electrical specifications must
be carefully observed. However, the availability of mercury switches in
Mercoid controls provides a unique advantage to the specifying engineer as they offer the capability for handling more demanding electrical loads than a snap-action switch. The mercury switch is preferred
for higher alternating or direct currents, both in resistive and inductive
loads.
In addition, the sealed mercury switch offers a level of inherent protection in hazardous conditions. It also provides excellent long-term
reliability where control actuation is infrequent as the sealed switch
configuration protects against contact corrosion which can cause
other types of switches to malfunction.
Mercury switches are also ideal for low-voltage and low-current (dry
contact) circuits such as encountered in computer controlled applications. However, the design engineer should give consideration to concerns about potential mercury contamination in switch applications
where this may be a factor.
In applying Mercoid Bourdon tube pressure switches, the use of a
surge tank, snubber and/or capillary tubing connection is recommended where pulsation or pressure surge cannot be avoided.
Additional protection against vibration and pulsation can be obtained
by specifying the Delrin bushed movement option.
Performance
In general, differential pressure controls and gages will perform best
when provided with the maximum differential pressure signal you can
obtain in the application.
Higher-range gages and controls are generally less susceptible to
problems related to vibration and shock, mounting position, temperature changes and accumulation of dirt and moisture. They are therefore easier to install and maintain. For example, when using a Dwyer
Additional Design Precautions continued on next page
3
pg 4
12/10/03
6:09 PM
Page 1
helpful information
Additional Design Precautions for Mercoid Products, continued
For steam service of 35 psig or higher, or high temperature media, a
siphon or remote connection is recommended to ensure that the ambient
temperature rating of the switch is not exceeded.
When applying a Mercoid Bourdon tube pressure switch with flammable,
hazardous or toxic gases or liquids, a stainless steel Bourdon tube control
should be specified as the welded Bourdon tube will reduce chances of
leakage in case of fire. For applications with any chloride media, the use of
a 316SS Bourdon tube pressure switch is also recommended. For additional protection, a diaphragm seal can be specified to prevent corrosive,
viscous or other damaging media from entering the Bourdon tube in the
control.
An over pressure diaphragm should be specified where the normal system
working pressure is low but pressure may occasionally rise above the
range of the control to as high as 5000 psig. The over pressure seal is
designed to protect the control if pressure increases beyond a predetermined point. When a set range is exceeded, the diaphragm seats and no
further motion is allowed, effectively limiting transmitted pressure.
As with all instrumentation, care should be taken to avoid freezing of the
media in the pressure element to prevent operating failure and damage to
the control.
In applying bulb and capillary temperature controls, specifying a protective well for the bulb may be advisable. The well will permit removal
of the control from the system without the problem of escaping media
or the need to shut down the system. In addition, the well may provide
required media compatibility. However, protective wells do increase the
response time of the temperature control, a factor to be considered in
their specification.
Level controls with cast iron housings should not be specified for use
with flammable, explosive or toxic media. In the intense heat of a fire,
cast iron housings can crack and release the media.
Where a liquid level control must function reliably under conditions of
extreme vibration, a special anti-vibration mechanism is available and
should be specified.
Specifying engineers should obtain a free copy of the Mercoid
Catalog, Bulletin E-60-M, a technical guide to the selection and
application of Mercoid DA Series temperature and pressure controls.
Finally, consult the factory or Dwyer field sales engineer if you have
any questions regarding the application of Mercoid products.
Glossary of Terms
Absolute Pressure (psia) – The total force per unit area exerted by a
fluid. The sum of atmospheric and gage pressures.
Alternating Current (AC) – Current that reverses polarity at a uniform
frequency.
Atmospheric Pressure – The force exerted per unit area by the weight
of the atmosphere.
Cavitation – Process in which small bubbles are formed and implode
violently.
Contacts – Elements used to mechanically make or break an electric
circuit.
C v or Valve Flow Coefficient – The number of US gallons per minute
of water at 60°F that will pass through the valve with a pressure drop
of 1 psi.
Direct Current (DC) – A current with a constant polarity.
Double Pole Double Throw (DPDT) Switch – Two separate switches
that operate simultaneously, each with a normally open and a normally closed contact and a common connection.
Gage Pressure (psig) – The measure of force per area exerted by a
fluid using atmospheric pressure as the zero reference.
Humidity – The amount of moisture in the air.
Impedance – The opposition in an electric circuit to the flow of an
alternating current consisting of inductive reactance, ohmic resistance
and capacitive reactance.
Maximum Surge Pressure – Safe pressure for the switch housing but
which may damage the mechanism by continuous or repetitive application.
Normally Closed Switch – A switch in which the contacts are normally closed. Actuation opens the contact.
Normally Open Switch – A switch in which the contacts are normally
open. Actuation closes the contacts.
NPT – National Pipe Thread.
Null Switch – A floating contact switch with a zone of no contact.
Often used to operate reversible motors.
pH – An indication of the acidity or alkalinity of a solution in units
ranging from 0 (most acidic), to 7 (neutral), to 14 (most alkaline).
Pressure Drop – The difference in upstream and downstream pressure of the fluid flowing through a valve.
Range – The span of differential pressures or flow rates within
which the sensing element of a given switch can be set to actuate an
electric switch.
Rated Pressure – The maximum pressure that the actuating components of the switch in contact with the media can withstand continuously and/or repeatedly without risk of permanent damage.
Relative Humidity – The ratio of the quantity of water vapor in the
air to the quantity of water vapor required for saturation at the same
temperature.
Repetitive Accuracy – The ability of a pressure or flow switch to
operate repetitively at its set point under consistent conditions.
Saturation Point – The point at which condensation is formed.
Serial Transmission – Sending one bit at a time on a single transmission line.
Set or Actuation Point – The exact air pressure or flow rate which
will cause the electric switch to actuate.
Single Pole Double Throw (SPDT) Switch – A switch combining
both normally open and normally closed switch contacts.
Solid State – Any element that controls current without moving
parts, vacuum gaps or heated filaments.
Temperature Compensation – The correction for the influence of
temperature on a measurement.
Transducer – Any device that generates an electrical signal from
physical measurements.
Transmitter – A device that translates the low-level output of a sensor or transducer to a higher level signal suitable for transmission
to a site where it can be further processed.
Viscosity – The resistance of a fluid to flow when subjected to shear
stress.
4
pg 5
12/10/03
6:19 PM
Page 1
products from Dwyer
Series 1223
Flex-Tube® U-tube
®
Magnehelic differential
pressure gage
Model 424 Durablock®
Inclined-Vertical
®
Capsuhelic differential
pressure gage
Mark II
Series 475
Mark III
handheld
digital
manometer
Series 490 wet/wet
handheld digital
manometer
Photohelic® pressure
switch/gage
Manometers
Dwyer manufactures a wide variety of virtually unbreakable plastic
manometers. Both portable and stationary manometers of the U-tube,
well-type, inclined and inclined-vertical types provide for the measurement
of low range air pressures, pressure differentials and vacuum. Several
models of Flex-Tube®, U-tube and Slack-Tube® (roll-up) manometers provide high accuracy at low cost for field work. Mark II molded styrene-acrylonitrile plastic models serve minimum-cost industrial applications.
Durablock® solid acrylic machined manometers function as standard references in the laboratory and for field work as well. New handheld digital
manometers offer convenience and accuracy in compact, portable units.
Mini-Photohelic differential
pressure switch/gage
Differential Pressure Gages and Switch/Gages
Series
7000B
Spirahelic®
gage
Series 7100
Spirahelic® gage
All Dwyer dial-type differential pressure gages employ the
Magnehelic magnetic linkage principle to measure differential pressures from 0.25˝ Water Column (w.c.) to 30 psig in total pressure
environments up to 500 psig. This family of gages provides a direct
indication of differential pressure on easy-to-read 4˝ dials
(Magnehelic®, Capsuhelic®, Photohelic®, and Capsu-Photohelic®
gages) and 2-1/2˝ dials (Minihelic®, Mini-Photohelic® gages) utilizing a reliable, shockproof, diaphragm actuated mechanism that provides a low-cost gage with high performance. While primarily
applied in the measurement of low differential pressure in air and
gases, Dwyer Capsuhelic® differential pressure gages are suitable
for use with compatible liquids. Standard Capsuhelic® differential
pressure gages and Capsu-Photohelic® switch/gages have aluminum bodies; brass bodies are available and are required for water
service. New Mini-Photohelic® differential pressure switch/gage
combines the time proven Minihelic® II differential pressure gage
with two SPDT switching setpoints.
The Dwyer Photohelic® and Capsu-Photohelic® series of differential
pressure switch/gages add phototransistor actuated relays with
easily adjusted set points to provide low and high limit electrical
control in addition to the measurement of differential pressure. All
of these gages are commonly employed to measure and control
pressure, velocity, or flow in stacks, air conditioning systems and
clean rooms, to monitor furnace draft, to indicate pressure drops
across orifice plates or venturi tubes, and to measure liquid levels
with bubbler systems, fume hood exhaust velocities, blood or respiratory pressure in medical equipment, cooling air pressure in
electronic equipment enclosures, etc.
Series DPG
digital
pressure
gage
Series
64000
Stainless
Steel
Pressure
Gage
Series
62000
Pressure
Gage
Pressure Gages
Dwyer Spirahelic® gages incorporate spirally and/or helically wound
Bourdon tubes. All feature solid-front design with a simple, reliable direct
drive mechanism. Models are available in ranges from 0-30 to 0-10,000
psig and metric equivalents in kPa, MPa and Bar. Units are available in
both turret and panel mounts, digital displays, NEMA 4X housing, and
accuracies up to ±0.25% of full scale, ASME Grade A, 2A & 3A.
Special Test Gages feature a precision knife edge pointer, finer minor divisions and a mirrored band to prevent parallax error.
For digital indication, the Series DPG offers exceptional accuracy (±0.25%
of full scale) in a NEMA 4X housing. The DPG is battery-powered, has a 4digit display to reduce reading errors, and is an economical replacement
for outdated analog gages.
Other pressure gages available include the Series 62000 and 64000. The
Series 62000 is an extremely versatile, low cost gage that offers a dual
scale in psi and kPa, with ranges up to 300 psig (2100 kPa) and selectable
back or bottom mounting positions. The Series 64000 stainless steel pressure gage is ideal for applications involving pressure spikes, vibrations and
pulsations, and delivers accurate readings in the harshest environments.
5
pressure products
Minihelic® II differential
pressure gage
Capsu-Photohelic®
pressure switch/gage
Model 1211
Slack-Tube®
roll-up
pg 6
12/16/03
5:46 PM
Page 1
products from Dwyer
Model 1638
Model H3
Model H-2
Duotect®
pressure
switch
Model 1950
explosion-proof
Series
A1PS/A1VS
Mercoid®
pressure
1000 Series
switch
pressure
switch
Pressure Switches
Series MDA
Pressure
Series MDS
Switch
Pressure
Switch
Model 1910
Model 1823
pressure/flow/level products
Dwyer offers a wide range of differential pressure switches, including
explosion-proof models, which are precision diaphragm operated and
which can be actuated by positive, negative or differential pressures.
Designed for low and very low pressure differential, ranges from .03˝
w.c. to 200 psid are available. These switches are most commonly
used to control or prove air flow in air conditioning, refrigeration, ventilating and combustion systems. The W.E. Anderson® Model H3
Explosion-proof differential pressure switch serves process applications requiring higher ranges and operating pressures and/or aggressive gas or liquid media. Series MDA & MDS miniature pressure
switches are perfect for low pressure control. The MDS has a double
diaphragm design to protect against false actuation due to shock or
vibration, and the MDA has a field adjustable setpoint.
Flow Switches
Model V10
Flotect®
mini-size
flow switch
Series
616C
transmitter
Series 645
Wet/Wet
differential
transmitter
Mercoid® DA
Series
pressure
switch
The Mercoid® Division of Dwyer Instruments, Inc. manufactures a
broad line of Bourdon tube and diaphragm operated pressure switches, most models offering either mercury or snap action electrical
switches and adjustable deadbands. Ranges to 8000 psig are available
with explosion-proof or weatherproof options. The Mercoid DA Series
with optional mercury switches are well-known for their long term reliability and resistance to contact corrosion. They are ideal for both high
and very low direct current applications. For use in liquid and gas
applications.
W.E. Anderson® manufactures the unique dual pressure Duotect®
explosion-proof pressure switch with one diaphragm actuating two
snap switches. The switches operate independently of each other and
can be adjusted to settings of up to 1500 psig.
Series A1PS/A1VS are economical pressure switches that provide field
adjustable control and are available in vacuum, pressure or compound
ranges. The Series APS/AVS provides reliable switching for
pressure/vacuum alarms.
Differential Pressure Switches
Series 607
Series 605
transmitter
Indicating transmitter
Series
APS/AVS
adjustable
pressure
switch
Series 604A
transmitter
Model
V4-2-U
Flotect®
flow
switch
Differential Pressure Transmitters
The Dwyer 605 Differential Pressure Transmitter combines state of
the art sensor technology with the proven design of the Magnehelic®
gage. The transmitter provides a standard 4-20 mA analog signal output in ranges as low as 0.1˝ w.c. to 200 psid and 0-3˝ w.c. to 0-100
psid for the Series 616C transmitter and is accurate within ±2% in
normal ambient temperatures. The Series 616C features exceptional
±1% accuracy. Applications include controlling of variable-speed
fans, blowers and positioning of system dampers. Supplies data on
air velocities in ducts and pressure drops across air filters. In the
medical field it can interface with a computer to provide blood and
respiratory pressure data.
Series 607 is ideal for reliability in critical applications where 0.25%
accuracy is required. It is designed to resist shock and vibration
while maintaining an accuracy of ±0.5%. The Series 645 is designed
especially for liquid and air applications and has an amazing accuracy of ±0.25%. It is available in bi-directional ranges and optional 3
valve manifold.
The W.E. Anderson® Division of Dwyer
Instruments, Inc. provides a line of
Flotect® vane operated flow switches
for installation in pipelines or ducts to
protect equipment against excess
flow, low flow, or stoppage of liquids,
Model V-6
gases, or slurries.
Flotect®
Explosion-proof construction is stanflow switch
dard for most of these switches. They
can be installed in pipes with diameters from
1/2˝ up to 20˝ or more.
Series
Other models such as the Model V10 are ideal
P5
for compact, cost effective requirements. The
shuttle
P5 PVC shuttle flow switch is designed with
flow
switch
one moving part for long life and minimum
maintenance.
Sight Flow Indicators &
Transmitters
Series SFI 800
sight flow
indicator/
transmitter
Model 360F
flanged
sight flow
indicator
6
Model 300
sight flow
indicator
Series GFC
gas mass flow
controllers/
meters
For liquid flow, the W.E. Anderson®
Division manufactures a broad line of
spinner, flapper, rotor and seethrough sight flow indicators for pipe
sizes from 1/4˝ to 4˝ in bronze, stainless steel and polysulfone housings.
Dwyer Series GFC gas mass flow
controller is a versatile solution to
applications where strict flow metering and controlling are imperative.
Field selectable 0-5V or 4-20mA linear output is standard.
pg 7
12/11/03
11:15 AM
Page 1
products from Dwyer
Below, left to right:
Rate-Master®
Models RMC,
RMB, & RMA
Below, left to right:
Series DR direct readBelow, left to right:
ing glass flowmeter;
Visi-Float®
Series VA Teflon®/
Models VFCII,
glass flowmeter
VFB, &VFA
Dial type Magnehelic®
air filter gage
Air Filter Gages
The Magnehelic® dial-type differential pressure gages and the
manometers described above are also offered as complete air filter
gage kits to measure resistance of air flow to indicate whether a filter
is clean or dirty. The kits are provided complete and ready to install,
including static pressure pick up tips and connecting tubing. The
Capsuhelic® gage is suitable for measuring differential pressure across
many liquid filters.
Flowmeters
Series 475-1TFM-AV air
velocity kit
Model VT-200
vane thermoanemometer
Model 400-10
air velocity meter
Model 471-3 digital
thermo-anemometer
Air Velocity Instruments
Dwyer differential pressure gages and manometers are offered individually and as complete air velocity measuring instrument kits. Supplied
with gage, Pitot tubes and connecting tubing, this group includes a
wide variety of types and price ranges from exacting laboratory needs
as well as plant or field use. These gages are calibrated to read air
velocity directly in feet per minute as well as static and velocity pressure in inches of water column. Pitot tubes are offered in numerous
models. The Series 641 Air Velocity Transmitter delivers precise readings in ranges to 15,000 FPM or 75 MPS and has an optional LED readout. The VT-200 vane thermo-anemometer is the ideal instrument for
HVAC applications, measuring air volume, air velocity and temperature
and storing up to 1000 measurements with built-in datalogging capabilities.
Series L8 Flotect®
liquid level switch
Anderson Model
L-4 level switch
Level Controls
Level controls from the Mercoid® Division cover a
broad range of applications in the process, refining and utility industries. Chamber type level conModel OLStrols are available with operating pressure ratings
12 optical
to 2300 psig. The Series 190 displacer type conlevel switch
trol features adjustable level setpoints and is ideal
for industrial sumps. Other models available for
boiler water level control. Most Mercoid® level
controls are available with either mercury or snap
action switches. Explosion-proof float switches
Series F7 level
switches-vertical
with wetted parts of brass or stainless steel are
available from W.E. Anderson® Division to monitor liquid levels in tanks. Explosion-proof float
switches with wetted parts of brass or stainless
steel are available from W.E. Anderson® Division
to monitor liquid levels in tanks. The L-8 Level
Mercoid
Switch features a leak proof body and optional
Series
weatherproof enclosure; Series L10 Level Switch
190
displacer installs easily in-wall or externally and accommotype level dates liquids with low specific gravities.
Series TS digital
temperature
switch
Series DA-7035
temperature switch
control
7
Series M-51
bimetal
temperature
switch
Temperature Switches
The Mercoid® DA-7035 Series bulb and capillary type temperature switches utilize the same
Bourdon tube switching mechanism as the DA
Series pressure switch. Temperature ranges to
530°F are available. The Series M51 is
designed for use as a limit or alarm switch or
as a fan control on furnaces, ovens, dryers,
etc. with ranges to 650°F. The low-cost Series
TS digital temperature switch is a state-of-theart control used in heating and refrigeration
systems.
level/flow/air velocity/temperature
Dwyer flowmeters are used in a multitude of applications in industrial,
commercial, scientific and medical equipment where the flow of air,
water, oil, or compatible gases or chemicals must be monitored or
controlled. Dwyer offers a multitude of variable area flowmeters for
these applications. Three sizes are offered in the extremely popular
Rate-Master® series. Manufactured from durable molded polycarbonate, choose from the many available ranges in air (0.1 to 1800 SCFH)
or water (1 GPH to 8 GPM). Dwyer’s Visi-Float® flowmeter series,
manufactured from machined acrylic, are available in three body sizes
and many ranges – 0.1 SCFH to 100 SCFM of air and 0.6 GPH to 20
GPM of water. The latest edition to Dwyer’s variable area flow meter
family is the Series UV Ultra-View™. Highly engineered, the Series UV
flow meter is made of Polysulfone and does not contain any metal wetted parts, making the Series UV perfect for applications involving ultrapure water. Units are extremely accurate and can withstand 100 PSI
(10.3 bar) pressure at 212°F (100°C). Dwyer’s VA glass flowmeters
offer superb precision and control. Materials of construction and universal scales offer the ideal flexibility when measuring different gases
and liquids. The Series DR direct reading flowmeters give users the
overall advantage of glass flowmeters while displaying flow rates on a
direct read scale.
Series L10
Flotect® mini-size
level switch
Model 250.5
Durablock®
inclined manometer
Mark II
Inclined-vertical
Right:
Series UV
UltraViewTM
polysulfone
flowmeter
pg 8
12/11/03
11:24 AM
Page 1
products from Dwyer
New Products from Dwyer Instruments, Inc.
2500
32DZ
TST
16S
temperature/valves/combustion testing/new products
Temperature/Process Controls and Sensors
The Love Controls Division manufactures a wide variety of temperature/process controllers for the packaging and molding industries.
These controllers are available in 1/4, 1/8, 1/16 and 1/32 DIN sizes.
Selectable control ON-OFF, P, PI or manual PID, or automatic SELFTUNE® PID control is available. Series TST dual probe digital temperature switches are economically packaged with three SPST relays for
refrigeration and defrosting applications.
Minihelic® II
differential
pressure gage
Mini-Photohelic
differential pressure
switch/gage
Series 490 wet/wet
handheld digital
manometer
Valves and Position Indicating Switches
3-way
butterfly
valve with
actuator
HiFlow™
valve
Self-acting
temperature
control valve
Position
indicating
switch
Series 616C
transmitter
Series DPG digital
pressure gage
Series DCT dust
collector timer controller
Series ABV automated two-piece
brass ball valve
Series 641 air
velocity transmitter
W.E. Anderson® pneumatic control valves are used in temperature control applications to protect sensitive equipment from overheating. Sizes
available are 1/2˝ to 2˝ in bronze or 316 stainless steel material.
Butterfly valves are also available from W.E. Anderson® in sizes 2˝ to
16˝ to meet your difficult application. 3-way butterfly valves with actuator are used to control the flow of water accurately in a water-side
economizer system. Series ABV automated two-piece brass ball valves
incorporate a full port brass ball valve for great flow rates with minimal
pressure drop. Proximity® Controls Division manufactures position indicating switches that can mount on the Hi-Flow® valves and Plast-A-Vane®
butterfly valves to give visual indication of and switch output of the valve
position.
Series SFI 800
sight flow indicator/
transmitter
Series VR
View-Rite
Level
Indicator
Series UV
Ultra-ViewTM
polysulfone
flowmeter
Combustion Testing Instruments
Individual Dwyer instruments measure
furnace draft, the CO2 content of flue
gases, stack temperature, and smoke density. Usually supplied as a complete,
portable kit for combustion efficiency test- Series
ing, these instruments serve to adjust gas, 450 CO
oil, or coal fired furnaces and boilers for Monitor
No. 1200-B
maximum combustion efficiency.
Combustion Test Kit The Dwyer CO indicators and monitors
2
are also available separately, in various ranges for use in testing
atmospheres on board ships and submarines, in greenhouses and in
CO2 blanketed flammable liquid tanks and compartments. The Dwyer
450 CO monitor is ideal for quickly monitoring carbon monoxide in
ambient air and for detection of Carbon Monoxide in residential/commercial heating systems. Alarms may be set to give an audible indication of reaching a threshold.
Series PBLT (left) &
SBLT submersible
level transmitters
Series P4
Ryton® Piston
Flow Switch
8
Series MPC
pump controller
Series PLS
paddle level
switch
Series TS digital
temperature
switch
16S
Series
450 CO
Monitor
pg 9
12/10/03
6:32 PM
Page 1
pressure
Static Pressure Sensor
Main Burner
Air Flow
Main Valve
A
Duct
B
Control
Valve
Regulat or
Gas
Pressure Tap
Pilot Gas
Series 475
Durablock®
Inclined Manometer
Magnehelic® Gage
Measuring static pressure in an air duct or plenum.
Static pressure relative to atmosphere down to less than .01” wc
can be measured directly using a Dwyer Magnehelic® differential
pressure gage or any Dwyer manometer, inclined or vertical. If a
manometer is used, an inclined type may be preferred to provide
adequate resolution, particularly at very low pressures.
A static pressure sensor installed in the duct or plenum and connected to the high or low pressure port of the gage, as appropriate, does the job. While a static pressure sensor, or tip (A in the
illustration) is recommended to reduce the effects of the turbulence, a flanged connection to a hole free of burrs in the wall of
the duct (B) is also satisfactory for static pressure measurements when static pressure is relatively high and velocity relatively low.
Digital Manometers used to check
gas pressure to a heating burner.
Alarm Lamps
Power Cord
Photohelic®
Switch/Gage
Furnace
Burner
To Dialysis Machine
Durablock®
Inclined Manometer
Flue
Probe
Through
Inspection
Door
Using a draft gage to adjust for efficient
combustion.
®
This portable monitor uses a Photohelic
switch/gage to show pressure and actuate hi-lo
alarm signals during kidney dialysis.
The amount of draft over the burner fire in oil, gas, or coal fired
residential, commercial, or industrial furnaces and boilers is an
important factor in combustion efficiency. A Dwyer Durablock®
portable inclined manometer (when used in this application, it
is commonly called a “draft gage”) provides an easy, accurate
measurement of the negative pressure over the fire or in the
flue. A Magnehelic® differential pressure gage can also be used
to make such a measurement. It offers advantages if continuous monitoring requires a permanent installation; it is easy to
read, has no fluid to evaporate, and costs less. To optimize furnace combustion efficiency, use a Dwyer Model 1200 combustion test kit which tests for draft, CO2, smoke density and stack
temperature.
This application for the Dwyer Photohelic® differential pressure
switch/gage utilizes a standard unit as a self-contained arterial
blood pressure monitor to be used with any kidney dialysis
equipment. The gage is connected to drip chamber in the arterial blood line and monitors the pressure in the chamber.
Instead of inches of water column, the gage is calibrated in millimeters of mercury. When blood pressure falls below or
exceeds preset limits, a buzzer sounds and a “high” or “low”
lamp lights which, for maximum patient safety, must be reset
manually when pressure is again within the preset limits.
9
measurement
Checking the gas pressure to a heating unit on the burner side
of the regulator is a standard installation and service routine.
The Dwyer Series 475 Handheld Digital Manometer is a lowcost, durable device that is easily transportable in a pocket or
briefcase. Units are highly accurate with 0.5% full scale accuracy. Some servicemen prefer our portable Dwyer Magnehelic®
differential pressure gage with dial type scale for field use.
pg 10
12/10/03
6:28 PM
Page 1
pressure
Differential pressure
gage assists
operator in
adjusting venturi
pressure drop in
dust scrubber.
Water Supply
Nozzles
Venturi Slot
OPEN
CLOSED
Magnehelic®
Gage
HI
Air Flow
Dirty Gas
Duct
This scrubber design
removes unwanted dust
Magnehelic Gage
or particulate matter
from air or gas using an
adjustable throat venturi.
To adjust the pressure
LO
HI
drop across the venturi,
a jack-screw-actuated
sliding vane varies the
Drop Legs
slot width. A permanently
mounted Dwyer
Clean
Drain
Gas
Magnehelic® differential
pressure gage indicates
the venturi pressure drop while the operator adjusts to the
desired or design setting. Where water may possibly enter the
gage sensing lines, as in this application, drop legs with drain
valves are needed to permit draining the lines at their lowest
point. Good engineering practice dictates that the Magnehelic®
gage always be mounted above the sensing tap when possible
to prevent moisture accumulation in the lines and gage. At minimum, mount the gage above the lowest point in the sensing
lines.
measurement
®
Damper
Gage indicates fire damper position in
heating/AC duct.
The Dwyer Magnehelic® or Minihelic® differential pressure
gages provide convenient visual indication of HVAC system fire
damper position. Mounted in access doors (or another convenient location) with the high pressure port sensing upstream static duct pressure, the gage will read upscale should the damper
close due to some failure. During system operational checks,
each damper reaction can be easily monitored. This application
eliminates difficult and time-consuming visual inspections - and
encourages more frequent inspections for proper operation. If
the rear of the gage will be exposed to dust-laden ambient air, a
filter plug should be placed in the pressure port and vented to
the atmosphere to prevent dust from accumulating in the gage
over a long period of time.
Air/Gas Out
Air Supply
HI
Filter
2
LO
B
Magnehelic®
Gages
A
1
Processor
or
Conditioner
LO
Magnehelic Gage
HI
®
Air/Gas In
Blower
Dwyer gages indicate pressurization of
special rooms.
A choice of several Dwyer products will monitor or
protect this processor.
A zero-center Dwyer Magnehelic® differential pressure gage
with an 0.25˝ wc range either side of zero makes an effective
monitor for proper operation of room pressurization systems.
In the example, differential gage B has its high pressure port
open to room 2 and its low pressure port to room 1; gage A
has its high pressure port open to room 1 and its low pressure
port open to the atmosphere. With the makeup air supply
damper adjusted properly, room 2 will be a higher pressure
than room 1 which is at higher than atmospheric pressure; both
gages will read positive. Should the air supply to room 2 be
obstructed, gage B will read negative. If the air supply fails
entirely, both gages will read zero. For even better security, a
Photohelic® switch/gage will provide automatic alarm or startup of a backup system.
When air or other gas must be pumped through a processor,
measuring the differential pressure across the blower with a
Magnehelic® differential pressure gage will monitor the flow
rate as a function of blower static pressure to indicate proper
operation. As an alternative, a Dwyer Photohelic® switch/gage
can be used where deviations from normal flow due to filter
loading, other restrictions in the system or blower failure
require automatic shutdown of the system. Either a Minihelic®
differential pressure gage or a Mark II manometer will serve if
a lower cost gage is desired. If no visual gage is required, a
Dwyer differential pressure switch will provide the automatic
shutdown or alarm function.
10
pg 11
12/10/03
6:35 PM
Page 1
pressure
Well-Type
Manometer
Sensing Ports
HI
Jet
Supply
Gas
Container
Under Test
LO
Stack Gas
Flow
Magnehelic® Gage
Seal
Shop Air
Regulator
Valve
Sensitive gage measures low flow of stack gas.
Dwyer well-type or inclined manometers used to
check for leaks in containers or assemblies.
This setup provides a low cost means of checking containers or
assemblies for no leakage or an acceptable rate of leakage. With
the unit under test in place on the seal, the operator opens the
valve to pressurize the system to the test level set by the regulator. After the well-type manometer stabilizes, the valve is
turned off. Any leakage is reflected as a drop in the manometer
reading, the leakage rate being proportional to the rate of drop
in the reading. A Dwyer inclined manometer can provide an even
more sensitive indication if required.
Test Seal or
Connection
Fill Pipe
Fitting
Flowmeter
Magnehelic® Gage
Shop
Air
Dryer
Regulator
Valve
Hose
Control
Panel
Another system of leak testing uses a Dwyer
flowmeter.
In-house engineers use a Dwyer gage on
production line test for integrity of auto fuel systems.
A fast, repetitive check for leakage in various containers, valves,
assemblies, etc. can be made with this test setup. During testing, the valve is opened after the dry air supply is set to the
proper test pressure. As a low range Visi-Float® flowmeter is
used to obtain sensitivity, the float will go to the top of the bore.
However, as soon as a unit under test is placed in position, the
float will fall to the zero mark if no leakage exists. The rate of
any leakage will be a function of the flow indication. Dry air is
usually necessary to prevent the float from sticking in the bore
due to accumulated moisture.
An automobile manufacturer uses an in-house designed system
for production line testing of fuel systems. The total system is
a complex, integrated fluidic circuit that charges the automobile’s fuel system through the gas tank fill pipe. One section of
the system senses leaks due to disconnected lines of faulty
connections by monitoring the differential pressure between
the auto fuel system and a reference tank with a Magnehelic®
differential pressure gage after the charged system is sealed
off.
11
measurement
In a hostile environment or in very low flow situations such as
those encountered in stack gas flow measurements, flow can be
measured more reliably by a proprietary device called a “fluidic
flowmeter”. A jet of compatible supply gas envelopes both symmetrically placed sensing ports but is displaced in proportion to
the flow of stack gas being measured. This results in a difference in pressure between the ports when flow is other than zero,
causing the Dwyer Magnehelic® differential pressure gage to
read upscale. Calibration can be direct or in inches of water in
conjunction with a calibration curve or table. This device can be
cleaned remotely by injecting solvent into the system. It also
provides a measurement “gain” enabling lower velocity readings
to be taken than is possible with other techniques.
pg 12
12/10/03
6:37 PM
Page 1
pressure
HI
LO
Magnehelic® Gage
Needle
Valve
Test Seal
or Connecti
1˝ Dia. Stainless Steel
Spirahelic® Gage
3
4
Shop Air
Solenoid
Valve
Regulator
Inflatable
Life Raft
Push button
measurement/control
Leak testing done with low range differential
pressure gages.
This setup provides a very sensitive and relatively fast method of
leak detection. With one hand, the operator places the unit to be
tested on the test seal and, with the other hand or one foot, operates the solenoid valve control button. With the unit under test
in place, the normally open solenoid valve permits equal pressurization of both sides of the Dwyer Magnehelic® differential
pressure gage, with a resulting zero reading. The needle valve is
adjusted once to equalize the time it takes to pressurize both
gage chambers and to minimize upscale gage readings during
pressurization. When the solenoid valve is activated (closed) any
leak quickly reduces the pressure on the low side of the gage
and an upscale reading results. The availability of very low range
Magnehelic® gages allows selection of a model which will quickly respond to a small leak with a significant reading, even at
modest test pressures. As an alternative, use a Photohelic® differential pressure switch/gage to provide an alarm or, in automatic testing, “kick-out” of the leaky unit.
Inflatable life rafts include small 1 inch diameter
gages.
Inflatable life rafts used on military and commercial aircraft
require highly reliable components for obvious reasons. The
inflation systems on some of these rafts include a very small
version of the Spirahelic® gage to reveal the pressure in the
compressed air bottle so it can be easily checked prior to flight.
A Spirahelic® gage in a stainless steel case only one inch in
diameter provides the required performance and reliability.
Static Pressure Sensor
Duct
Valve
HI
Air Flow
Differential
Pressure Switch
Indicator
Lamp
LO
Series 490
Wet/Wet
Handheld
Digital
Manometer
Power Supply
Measure pressure in hydronic applications.
A differential pressure switch and warning lamp
monitor static pressure.
The Dwyer Series 490 Wet/Wet Handheld Digital Manometer is
a portable, industrial instrument designed for processes with
liquids or gases. The 490 is often used to measure pressures
in hydronic applications, but with all 316 stainless steel wetted
parts it can also be used in systems where aggressive media is
present.
In the above application, the 490 is used to measure the pressure differential on a control valve in a multi-story building
water system. The user balances the pressure differential on
the control valve to ensure every floor receives approximately
the same pressure.
The existence of a static pressure above or below a required
level (compared to atmospheric) is easily determined by connecting an appropriately installed static pressure tip to the
appropriate port of a differential pressure switch, such as a
Dwyer Series 1600, 1800 or 1900 differential pressure switches. When the pressure reaches the preset switch point, the contacts are closed to activate a warning lamp or other alarm
device. It is good practice to mount the differential pressure
switch with the ports down to prevent moisture from entering
the diaphragm chamber. The diaphragm should be vertical and
in the same plane as any vibration or anticipated shock movement.
12
pg 13
12/10/03
6:39 PM
Page 1
pressure
High
Pressure
Indicator
Low
Pressure
Indicator
Series DPG-100
Digital Pressure Gage
Duotect® Dual
Pressure Switch
Diving
Tanks
Large
Tank
Large
Tank
Pressurized Line
One diaphragm actuates two independent
explosion-proof switches in Duotect® pressure
switch to monitor pressure.
Filling Scuba Diver’s Air Tanks.
Audible
Alarm
Exhaust
Blower
and Air
Filter
Series 607 Transmitter
HI
LO
Pressurized
Clean Room
LO
HI
LO
Photohelic®
Switch/Gage
Fume Hood
To Work
Space
HI
Mini-Photohelic
Signal
Loop
Transmitter and Photohelic® switch gage
monitor negative pressure during asbestos
removal operations.
Portable Monitor
and Alarm Units
During asbestos removal operations, it is essential to monitor and
record the negative pressure compared to atmosphere which must
be maintained in the work space to prevent escape of airborne
asbestos particles. A Dwyer Series 607 transmitter provides a 4-20
mA control loop signal proportional to pressure to a strip chart
recorder with a 4-20 mA input configuration. Thus, a permanent
record of work space pressure is obtained. To provide an audible
alarm should the pressure go positive for any reason, a Dwyer
Model 3000-00N SR Photohelic® switch gage is connected in parallel with the transmitter sensing line and connected electrically to
an audible device. The Model 3000-00N-SR features an offset zero
pressure point to actually allow below zero indication of pressure
plus a single setpoint adjustable from the front of the gage for setting the alarm level at or within a few hundredths of an inch of
water column of zero room pressure.
Compact switch/gage monitors pressure,
actuates alarm.
This portable pressure monitor alarm utilizes a Dwyer MiniPhotohelic differential pressure switch/gage to monitor either
positive pressure, as in a clean room, or negative pressure, as
in a fume or paint spray hood. It sounds an alarm, both audible
and visual, when pressure exceeds either a preset high or low
limit. The unit can be used temporarily to verify proper operation after initial installation. Or it can be mounted permanently
for continuous monitoring. In applications where a single fixed
alarm pressure level is sufficient, a differential pressure switch
can be used instead.
13
control
High pressure lines or systems for air, gases, or liquids can be
monitored for proper pressure between desired limits with a
Duotect® dual pressure switch. Independent low and high alarm
or control points can be set from 5 to 1500 psig. With two individual switches operating from a common diaphragm, one
Duotect® switch does the job. The high and low pressure indicators or alarms are activated only when the limits are exceeded;
both are deactivated when the pressure is within the limits. The
Duotect® switch is explosion-proof and can be used with hazardous media or in explosive atmospheres.
The Dwyer Series DPG with oxygen cleaning and 5000 psi range
is used in gas blending applications for filling scuba diver's air
tanks. The DPG is the master mixing gage in this manifold
apparatus. Two or three gases may be blended with the manifold to produce the appropriate blend of breathable gas depending on the diver and the depths they will reach. With the flow
adjustment knobs and the 0.25% full scale accuracy DPG, precise tank charging rates are maintained.
pg 14
12/10/03
6:40 PM
Page 1
pressure
Battery
Condenser
Bellows
Lint Slide
Fan
Connecting
Cable to
Control Unit
Minitactor
Switches
®
Differential
Pressure
Switch
LO
Mouth Tube
HI
Lint Flue
Enclosure
control
Switch senses air pressure changes in textile
equipment.
Physically challenged individuals control equipment with Dwyer switches.
In the textile industry, a Dwyer differential pressure switch is
used to determine when cotton is passing through a battery condenser. It is used with a control unit to stop a water pump and
turn down a burner when no cotton is being ginned. The switch
works by sensing the difference in air pressure between the two
sides of the condenser screen. When no cotton is on the screen,
the pressure difference will be almost zero. When a batt of cotton is being condensed, the air pressure inside the screen will be
lower than the air pressure in the lint flue. the switch senses this
difference and closes an electrical contact. Filters are recommended at the tap end on the sensing lines in this type of application, as particulates can clog the sensing lines or accumulate
in the switch.
Blower or
Compressor
Plenum
or
Tank
Photohelic®
Switch Gage
Photohelic®
Switch/Gage
(Low Pressure
Applications) Differential
Pressure
High
Switches
Limit
(Low Pressure
Switch
Applications)
HI
Duct or Pipe
Duotect®
Pressure
Switch
(High Pressure
Applications)
Low cost Dwyer Minitactor® differential pressure switches will
sense pressures produced by physically challenged individuals
to control electrical devices which render them assistance. The
soft cushion-bellows can be squeezed by almost any body contact and the gooseneck mounted mouthpiece blown into by
mouth to activate the Minitactor® switches. The mouthpiece can
also be teed into a third Minitactor® switch on the low pressure
side so both blowing and sucking can produce separate control
functions. These sensors are both very sensitive and safe as the
electrical circuits are isolated from the individual by the rubber
tubing.
LO
Glove
Box
Solenoid
Valve
Pressure
Relief
Valve
Regulator
Control
Unit
HI
Vent to
Atomosphere
in Safe Area
Low
Limit
Switch
HI
Controlling pressures in air or gas systems.
Gas Supply
Air pressure can be controlled in a system by using a Dwyer
Photohelic® differential pressure switch/gage, one or two
Dwyer differential pressure switches, or a W.E. Anderson
Duotect® pressure switch, depending on the range of control
and/or levels of pressure involved. All of these switches monitor the pressure in the system and will cause the pressure
source - a blower, compressor or pump - maintain the system
pressure within the preset high and low levels. For systems
using low pressures (.01˝ wc to 10 psig), the Photohelic®
switch/gage or Dwyer pressure switches are the best choice.
For higher system pressures (5 to 1500 psig), we recommend
the Duotect® pressure switch. When you install differential
pressure switches on air systems, it is best to mount the switch
with ports down to prevent moisture from entering the
diaphragm chamber - and with diaphragm vertical and in the
same plane as any vibration or anticipated shock movement.
Zero-center switch/gage controls the inert atmosphere in glove box.
A controlled inert atmosphere “glove-box” is used in the fields
of physical chemistry and metallurgy for handling and welding
special or hazardous materials. A Dwyer Photohelic® differential
pressure switch/gage serves as an automatic and readily
adjustable pressure control for the helium, argon or nitrogen
gas used in the system. The box is first evacuated, then pressurized with the required gas. Therefore, a zero-center
Photohelic® switch/gage is used, permitting both pressure and
vacuum to be read and controlled by a single gage. Use of the
low pressure gage connection (rear chamber of gage) and a
Buna-N diaphragm is suggested to minimize leaks from or to
the atmosphere.
14
pg 15
12/10/03
6:42 PM
Page 1
pressure
Differential
Pressure
Switch
Windspeed
Pickup
Tarpaulin Over
Grain Pile
HI
Blowers
Retaining Wall
Photohelic®
Switch/Gage
Blower
Control Unit
Switch/gage regulates pressure in air-inflated
buildings.
Grain piled out of doors must be protected from the weather by
a tarpaulin cover. To hold the tarpaulin in place during periods of
high wind, this system utilizes a row of exhaust blowers mounted through one retaining wall to create a negative pressure
under the cover. The blower control unit uses a Dwyer Wind
Speed Indicator pick-up to sense velocity pressure and activate
a Dwyer differential pressure switch at a pre-determined wind
velocity. Therefore, the fans are turned on only when necessary
to conserve electrical energy. A Photohelic® switch/gage could
also be used to provide readout of velocity pressure and visual
indication of the blower activation setpoint as well as easy field
adjustment of the setpoint to meet varying conditions.
To control pressure in air-inflated buildings, the high pressure
port of a Dwyer Photohelic® differential pressure switch/gage is
connected to a tap in the building wall. The unit senses overpressure that may over-inflate the building - or loss of pressure
that may result in collapse - and controls the blower to maintain
correct pressure. The gage is easily reset to conserve power or
provide extra pressure to resist strong winds. Although two regular pressure switches plus a latching relay may also control the
blower automatically at lower cost, the Photohelic® switch/gage
is preferred, as it permits both visual reading of inflation pressure and easy adjustment of set points to meet varying conditions.
Variable
Speed
Drive
Power To
Pump
Air Out
Mercoid
DA Series
Pressure
Switch
®
Air In
Blower
To Sprinkler
System Main
HI
Photohelic®
Switch/Gage
®
The Mercoid DA Series is the industry standard
pressure switch for fire pump controls.
Fire pump controls operate pumps, supplying water to building
fire sprinkler systems. These controls turn on the main pumps
when system pressure falls due to sprinkler heads being activated. Fire pump controls also turn on smaller make-up pumps
to maintain system pressure, which may fluctuate due to small
leaks. These controls almost always employ the Mercoid® DA
Series pressure switch due to its rugged design and high reliability over long periods of infrequent operation. The DA Series
switch provides independent high and low setpoints over the
entire pressure range of the switch to meet varying requirements from system to system. The low setpoint maintains minimum pressure required for proper system operation while the
high setpoint prevents damage due to over-pressurization of
the system.
Switch/gage controls blower speed to save energy.
Variable-speed blower drives are gaining popularity as a very
energy-efficient method of controlling air flow. In a typical system, a Dwyer Photohelic® differential pressure switch/gage
monitors the static or velocity pressure in the duct downstream
from the blower and, within the preset high and low pressure
limits of the null band, the switch/gage controls blower drive
speed to maintain the desired pressure. To meet changing conditions, the manual knobs on the Photohelic® switch/gage permit easy resetting of control limits.
15
control
Dwyer Wind Speed Indicator and differential
pressure switch control fans to hold down grain
pile cover.
pg 16
12/10/03
6:43 PM
Page 1
pressure
Mercoid® Series DA
Pressure Switch
LO
Photohelic® Switch/Gage
Wet Material
Input
Pressurized
Gas Out
Overpressure
Relief Valve
Dryer
Exhaust
Receiver
Damper
Dry
Material
Discharge
Hot
Air
Inlet
Gas
Supply
Compressor
control
Fuel savings result from switch/gage draft control.
Mercoid® Series DA pressure switch maintains
desired gas pressure in tank.
Automatic vent dampers conserve energy in residential furnaces
by closing completely when burner is off to prevent wasteful
heat loss up the flue. However, in some industrial heating applications like this asphalt plant dryer, burners run continuously. To
save energy, another form of automatic damper control maintains a constant exhaust draft at the point required for most efficient operation. In this application, a Dwyer Photohelic® differential pressure switch/gage monitors the negative static pressure in the dryer and maintains the desired draft by signaling the
damper actuator to change the damper position when the upper
or lower limit is reached. Cost savings can be substantial in high
fuel usage systems of this type.
Demand for compressed gas varies in this gas line. So a
Mercoid® Series DA adjustable deadband pressure switch is
included to turn the compressor on at low pressure and off
when the maximum pressure is reached.
Flue
Differential
Pressure
Switch
Air Inlet Shutters
Power
Vent
Fan
Drive Unit
Exhaust Fans
Flue Gas Heat
Extractor
Burners
Control
Unit
Photohelic® Switch/Gage
Power operated shutters on barn controlled by
Photohelic® pressure switch/gage.
Furnace protected from inadequate draft by
fail-safe differential pressure switch.
Controlled environment farm buildings are home to a variety of
livestock and temperature and ventilation are as important to
their well-being and growth as proper food and waste removal.
The Dwyer Photohelic® differential pressure switch/gage,
mounted in a control panel, will sense inside static pressure
compared to outside atmospheric conditions and adjust the
power operated shutters on the fresh air inlets. This maintains
the required negative pressure in the building to ensure proper
ventilation. Temperature sensors also provide input to control
fan speed as necessary depending on outdoor conditions.
The high cost of home heating fuels has produced demand for
more efficient furnace designs. One such furnace includes an
additional stainless steel cell through which flue gases are routed to extract heat otherwise lost up the flue. The relatively cool
flue gas then requires power venting by means of an induced
draft fan. A Dwyer differential pressure switch is built in to
prove adequate draft by sensing the negative draft pressure
compared to atmosphere. If the fan or pressure switch should
fail, the burners are shut off automatically.
16
pg 17
12/10/03
6:44 PM
Page 1
pressure
Data Recorder
Differential
Pressure
Switch
Stack
Fan
Component
Oven Doors
LO
Drop Leg
Safety is increased
when draft in the
smokestack is
monitored.
Differential Pressure Switch
Flue Gas
Flow
Power Supplies
Differential pressure switch protects products on
test.
The vast number of semiconductor devices manufactured for
high reliability applications in computer systems, particularly
memory devices, requires weeding out those that will fail early.
They are subjected to a burn-in process, i.e., power is applied to
the device to “exercise” it in a high ambient temperature. Fans
move air over a bank of heating elements and then over the
devices being processed. Failure of these fans can damage the
burn-in equipment as well as delay completion of the testing of
thousands of devices. A Dwyer 1900 Series differential pressure
switch is installed to monitor air flow and signal an alarm immediately upon cessation of proper flow.
Ventilation
Hose
Gas Fired
Heater
Manhole
Series 7112B Spirahelic®
Direct Drive Pressure Gages
Fan
Dwyer Model 1823
Differential
Pressure Switch
Process gage monitors line pressure.
Utility manhole ventilation air heater protected by
Dwyer differential pressure switch.
The 7112B Spirahelic® gage with direct drive triple wound
Bourdon tube and ASME Grade 2A accuracy is often used on
process lines to monitor pressures. Ranges from 30 PSIG up
to 10,000 PSIG are available along with several compound
ranges for systems that experience pressures below zero. The
triple wound Bourdon tube technology allows the Spirahelic®
Gage to withstand vibration, pulsation and shocks without
damage or the need for recalibration.
Manholes providing access to various underground utility systems must be ventilated with fresh air for worker safety. In cold
weather, heating the ventilation air also provides worker comfort. This small gas-fired heater can be inserted between the
ventilation fan and hose. A Dwyer differential pressure switch is
used to sense air flow through the heater as a function of static pressure. It will shut down the gas burner if the static pressure falls below a level indicating insufficient air flow due to fan
failure or an obstructed air intake.
17
control
In this boiler installation, a differential pressure switch signals
when the natural draft in the smokestack is insufficient, and
alerts the operator for corrective action. The low pressure port
of the switch is connected to a tap at the base of the smokestack
and the high pressure port is left vented to atmosphere. The
same set-up can also be used to monitor operation of forced
drafts and shut off firing if a fan fails. In addition to this switching function, a Dwyer Photohelic® differential pressure
switch/gage will also provide a visual indication when required.
Be sure to consider compatibility of the pressure switch components with the flue gases in applications of this type. In flue gas
application, it is wise to provide condensate drop legs and drain
valves in the sensing line.
pg 18
12/10/03
6:47 PM
Page 1
pressure
HI
Photohelic®
Switch/Gage
Web
Press
Rollers
Air Supply
Yarn
Differential
Pressure Switch
Valve
HI
Pull Rollers
Pickup
Tube
Carding
Machine
Compressed
Air Supply
Paper
Air Jet
Trumpet
control
Yarn size from carding machine controlled by
switch/gage.
When paper web breaks on printing press, air jet
reaches pressure switch, which signals control to
stop press.
The size of a “rope” of permeable materials, such as the yarn
produced by carding machines in the textile industry, can be
controlled by air pressure sensed by a Dwyer Photohelic® differential pressure switch/gage. On these machines, the amount of
fiber supplied for the yarn causes its diameter and density to
change proportionally. The backpressure created by a larger and
denser yarn in the trumpet increases the pressure sensed by the
switch/gage until the preset upper limit is reached and the
switch causes the carding process to slow down. When it slows,
the yarn becomes smaller and less dense until the pressure falls
to the switch/gage’s preset low limit and the carding unit is signaled to speed up. The amount of air supplied controls the
desired size of the yarn. Opening the valve reduces yarn size by
providing the preset backpressure from a less dense yarn and
vice-versa.
Large, high-volume web printing presses move paper through
the press from continuous rolls at very high speed. When the
paper strip, or web, breaks accidentally, the press must be
stopped quickly or a large amount of paper is lost and cleanup
takes valuable time. To prevent such losses, the integrity of the
web is often monitored by a Dwyer differential pressure switch
connected to a pickup tube opposite a jet of air on the other side
of the web. When the web breaks, the air flow from the jet causes pressure to rise in the pickup tube, closing the switch which
signals the main control unit to shut down the press. The pressman regulates the jet pressure to minimize air consumption
based on the desired response time.
Regulated
Air Supply
Processing
Unit
1950
Explosion-Proof
Differential
Pressure Switch
Relief
Valve
HI
Dispensing
Pump
®
Photohelic
Switch/Gage
HI
Drill Bit
Fill
Pipe
Magnehelic®
Gage
Vapor
Collection
Line
Gasoline
Line
Orifice
Drill Guide
Underground Tank
If drill breaks, switch/gage will stop machine.
Condensate
Drain Lines
Gasoline vapor recovery system.
Some area pollution control agencies require that 90% or more
of gasoline vapor vented at service stations when fuel is dispensed must be prevented from venting to atmosphere. Using
a dual hose dispenser, this vapor recovery system is a vacuum
assist, vapor burnoff type. The blower creates a low vacuum at
the nozzle, routing vapor from the automobile tank to underground storage tanks. As uncondensed vapor pressure reaches
2˝ to 3˝ w.c. pressure, a Dwyer 1950 Series explosion-proof
differential pressure switch activates a rooftop burnoff unit,
which ignites excess vapor. The Magnehelic® differential pressure gage mounted on the station wall monitors tank pressure
to verify system operation. The gage is calibrated in inches of
gasoline, from +6 to -2. This allows the operator to determine
the necessary level correction due to tank pressure prior to dipsticking the tanks through the fill pipe.
A Dwyer Photohelic differential pressure switch/gage on this
fixture detects breakage of drills or reamers in automatic
machines and shuts down the process immediately upon
breakage. It prevents additional damage where tapping or other
operations follow in the process. In the fully retracted position,
an orifice in the drill guide is located just above the cutting lip
of the drill. Regulated air pressure is supplied to the orifice and
teed to a Photohelic® switch/gage. As long as the drill is intact,
pressure remains high. If the drill breaks, the missing drill tip
allows pressure to drop below the minimum set on the gage
and the relay closure signals the process to stop. The
switch/gage will also actuate an alarm if desired. Although a
simple differential pressure switch could be used, the
Photohelic® switch/gage is superior for this application, as it
permits instant adjustment for various machine setups.
®
18
pg 19
12/10/03
6:49 PM
Page 1
pressure
Reversible Drive Motor
Series 645
Wet/Wet
Differential
Pressure
Transmitter
Adjusting Screw Drive
Adjusting Screw
Liquid Flow
Seal
LO
Test Fixture
Vacuum
Source
Three-valve manifold simplifies installation of
wet/wet differential pressure transmitter.
Photohelic®
Switch/Gage
Dwyer switch/gage controls tank fill valve setting.
This unique toilet tank fill valve replaces older ballcocks and
floats. It is controlled by a diaphragm exposed to the head of
water in the tank. An adjusting screw allows the installer to set
the correct level of water in the tank for proper flushing with
minimum water. During production, this fixture automatically
sets the adjusting screw to a common 18˝ to 20˝ water column.
The fixture draws a vacuum on the lower side of the diaphragm
to simulate water pressure on the top side and a Dwyer
Photohelic® differential pressure switch/gage samples this vacuum via the low pressure port. With presets at 18˝ low and 20˝
high limits, a reversible motor on the fixture engages the adjusting screw and drives it to the point where the valve closes in the
desired 18˝-20˝ range.
Pump Control
Panel
LO
Series A1
Pressure
Switch Pump
HI
Exhaust
Pre-Filter
Filter
Series V6
Flotect®
Mini-Size
Flow Switch
Magnehelic® Gage B
LO
HI
Blower
Material
Flow Out
Heater
Magnehelic® Gage A
Mercoid® A1 pressure switch and W.E. Anderson®
V6 flow switch are incorporated into irrigation
pumping station.
Air Flow
The pumping station is used to provide water for irrigation purposes and contains one to four pumps with a pump control system.
To protect the pump a loss of prime protection is included in the
system. A pressure switch is installed in the system and signals a
low pressure alarm. Then if the V6 flow switch signals no flow a
timer starts and if there is no flow through the system for a given
time period the pump is shut down. The flow switch by itself also
trips a low flow condition for pump shut down even if pressure
does not fall. The A1B-OP is perfect for this application as it was
designed to mount in the bottom of the pump station control panel.
It mounts flush through the bottom of the panel and comes complete with a sealing gasket and nut to make sure the switch seals
off tightly against the panel keeping it weatherproof. Mounting in
this fashion saves the cost of using weatherproof pressure switches. The V6 flow switch is also well suited for this application with
its robust and weatherproof design.
Two differential pressure gages reveal filter
condition in lab dryer.
This laboratory dryer is used to dry small batches of chemical
compounds, drugs, fertilizers, foods, etc., for research and development purposes or to prove production techniques. Room air is
drawn in through the pre-filter, passes through the blower and
over the heating coils. The blower forces heated air up through
the material to be dried. The Dwyer Magnehelic® differential
pressure gage A monitors the pressure drop across the material
to detect any blockage developing. The exhausted air then passes through a final filter. To monitor the condition of that filter,
Magnehelic® gage B measures the associated pressure drop.
Minihelic® gages would also be suited to this application.
19
control
When using differential pressure transmitters in fluid applications, it is essential to periodically make sure that there is no air
in the system, as this can cause erroneous readings.
Unfortunately, the necessary three-valve bleed system is often
expensive and large, making installation difficult and bulky. For
this reason, Dwyer offers the 3V option on all 645 Wet/Wet
Differential Pressure Transmitters. This compact, lightweight,
and economical bleed manifold is shipped factory-installed on
the 645, eliminating the hassle of constructing a custom apparatus. The 645, when combined with the three-valve option,
makes for an ideal setup to monitor hydraulic filter clogging or
other fluid pressure sensing applications.
pg 20
12/10/03
6:50 PM
Page 1
pressure
HI
LO
Static Pressure Sensors
Magnehelic®
Gage
Selector Valve
Air Flow
Filter
LO
HI
Static Pressure Sensors
Magnehelic® Gage
Air Flow
control
Several types of Dwyer differential pressure gages
are well suited to monitor the condition of filters.
Two filters served by one gage and Dwyer selector
valve.
A Magnehelic® air filter gage instantly reveals when filters need
servicing. Select a Magnehelic® gage model with range appropriate to the filter manufacturer’s recommendation for maximum
permissible pressure drop across the filter. Install the gage with
a red adjustable signal flag (optional) set at the maximum allowable pressure drop point for the air volume being handled. This
speeds the reading of gage, even by relatively inexperienced personnel. Portable kits complete with static tips, tubing and hardware are available. Instead of the Magnehelic® gage, our
Photohelic® differential pressure switch/gage will automatically
actuate an audible or visual alarm when filter needs servicing.
Where a very high degree of accuracy is required, an inclined
manometer, such as the Dwyer 100 or 200 Series Durablock®
models, can be used to measure pressure drop. If low cost is
most important, our Mark II, Model 25 manometer will indicate
pressure drop.
Where dual filters are installed, a single Magnehelic® differential
pressure gage can be used to monitor the condition of each filter, using the arrangement illustrated above. With the knob on
the Dwyer A-365 selector valve pushed in, the static pressure
sensors across filter A are connected to the appropriate ports on
the gage. Pull the selector valve knob out and you connect the
static pressure sensors across filter B to the gage. Be sure to
select a gage range appropriate to the specified pressure drop
for both filters. If desired, substitute a Photohelic® differential
pressure switch/gage or Durablock® inclined manometer for the
Magnehelic® gage.
Magnehelic®
Gages
Roll Filter
Pressure
Drop
Drive
Motor
Filter
Under Test
Air Flow
Static
Pressure
Sensor
Static
Pressure
Sensor
Filter "B"
Filter "A"
Current
Air
Velocity
Voltage
Differential
Pressure
Switch
LO
Blower
Variable
DC Power
Supply
HI
Differential pressure switch actuates roll filter
motor when dust reduces air flow.
Test unit compares efficiency of various filter
design.
When dust build-up on this roll filter increases the filter’s resistance to air flow, the increased pressure drop across the filter is
sensed by the differential pressure switch, which starts a motor
to roll a new section of filter into place. A Dwyer Photohelic®
differential pressure switch/gage can also provide this type of
automatic control. It has the added advantage of continuous
visual indication of the pressure drop for routine checking by
maintenance personnel, as well as front-mounted knobs for
instant adjustment of high and low pressure limits.
The basic function of this filter testing system is to aid in conserving energy. It provides accurate comparative data for similar filters to help the operator select or specify the filters that
provide maximum efficiency with minimum pressure drop. A
variable speed blower draws air through the filter under test.
Blower voltage and current are indicated on panel meters. One
Magnehelic® gage monitors static pressure on the blower side
of the filter, and exhaust air velocity is indicated by a second
Magnehelic® gage connected to a Pitot tube in the exhaust duct.
For a given air velocity, filter pressure drop and electrical energy required can easily be determined for various filter designs.
20
pg 21
12/10/03
6:52 PM
Page 1
pressure
Air Conditioning Unit
Exhaust
Spray Booth
Differential
Pressure
Switch
LO
Paint Arrestors
Mark II Manometer
Operator Cab
When A/C filters in operator’s cab need cleaning,
a Dwyer pressure switch actuates a visible or
audible warning.
Industrial spray-painting booths equipped with paint arrestors
need monitoring to indicate when arrestor maintenance is
required. The low-cost Mark II Model 25 manometer is widely
used for this. Usually, the manometer is mounted to the outside
wall of the booth for easy observation, and the low pressure tap
is made directly through the wall of the booth to the exhaust side
of the system. The manometer’s high pressure port is left
unconnected as the area around the spray booth is at ambient
room pressure. A Dwyer Vaneometer can also be used to check
face velocity at the open side of the spray booth.
Concern for efficiency and safety, as well as compliance with
federal regulations, has produced a need for operator enclosures on equipment used in areas with high ambient temperatures and heavy air pollution. Such enclosures are supplied with
filtered and conditioned air to insure operator comfort and safety. Dwyer differential pressure switches are specified to monitor
the pressure drop across the filters in the compact, heavy-duty
air conditioners installed in the cabs. The switches actuate a
visual or audible warning when filter cleaning or replacement is
required.
Exhaust
Filter
Door
Differential
Pressure Switch
Blower
®
Magnehelic
Gages
Filter
Door
Dust Bin
LO
Series DCT500
Low Cost
Timer
Controller
HI
Heater
Filter
Collection Hose
Oven
Control
Panel
Dust Collector Timer Controller shows filter
condition in dust collector.
This portable dust collector can be rolled from job to job in an
industrial building. An operator places the large diameter collection
hose where it is needed and dust is collected by filters located
inside the access doors on the units side. The top mounted blower draws air through the filters. To monitor the pressure drop
across the filters, the manufacturer supplies a Magnehelic® differential pressure gage. When the pressure drop due to dust build up
on the filter indicates that cleaning is necessary, the DCT500DC
Dust Collector Timer Controller is manually activated to initiate a
cleaning cycle which involves solenoid valves releasing pulses of
air. This process removes the dust from the filters where it drops
into a storage bin. A Dwyer Minihelic® differential pressure gage
can be used instead of the Magnehelic® gage, and, if automatic
cleaning is required, a Photohelic® differential pressure
switch/gage can provide the electrical contact to actuate the cleaning cycle when the pressure drop reaches the preset limit.
Oven Capacity
Blower
Heater
Commercial warming ovens include differential
pressure switch to alert operator if fan fails or filter
clogs.
Many large commercial warming and baking ovens require
forced air circulation. They are protected against overheating
due to blower failure or filter clogging by a Dwyer differential
pressure switch, which monitors the pressure drop between
the oven cavity and the inside of the fan duct. Should the pressure drop exceed the preset standard, the switch will turn off
the oven heaters and light a panel alarm indicator.
21
control
Low-cost Dwyer manometer indicates when to
change filters in industrial paint spray booth.
pg 22
12/10/03
6:53 PM
Page 1
pressure
Differential
Pressure Switch
Filter Unit
Filter Unit
Photohelic® Gages
Series DCT500
Low Cost
Timer
Controller
Hopper
Alarm light triggered by Dwyer pressure switch
alerts diesel engine maintenance crews to
service air cleaners.
Automatic filter cleaning control system.
An automatic filter cleaning control system is created with the
combination of the Dwyer Photohelic® switch/gage and a
DCT500 Dust Collector Timer Controller. The Photohelic® gage
monitors the filters for dust build-up. When the dust build-up
and pressure drop across the filters exceeds a preset limit, the
Photohelic® gage activates the DCT500’s cleaning cycle. The
DCT500 controls the cleaning process until the dust levels and
corresponding pressure drop on the filters falls back below the
preset limit. Static pressure tips and line filters are recommended to prevent migration of particulate into the Photohelic® gage.
control
The large air cleaners on diesel locomotives must be serviced
promptly when the particulate build-up on the filter element
exceeds a safe level. To monitor filter pressure drop in this
application, the engineers specified a Dwyer 1910 differential
pressure switch. It performs reliably despite severe shocks and
vibration as well as elevated ambient temperatures. When the
pressure drop exceeds the preset level of the switch, a red alarm
light goes on in the engine cab. The alarm is latched in the “on”
position, alerting maintenance crews at the destination to the
need for air cleaner service.
Filter Doors
Air In
Series DCT1000
with DCP
Dust Collector
Timer Controller
Air Out
Clean
Air Outlet
Filter Bags
HI
LO
HI
Dirty
Air
Inlet
LO
Shaft
Airshock
Blower
Motor Controls
Dust Hopper
Cooling air for big motor passes through filter
monitored by explosion-proof differential pressure
switch.
Bag house cleaning system uses Dust Collector
Timer Controller to initiate optimum cleaning
cycle.
This large electric induction motor has rotor mounted fans that
draw cooling air into each end of the motor, across the rotor,
and out through the stator into an exhaust duct. To prevent
accumulation of dirt and dust in the motor, incoming air is filtered. The condition of each filter is monitored by a Dwyer 1950
explosion-proof differential pressure switch which senses the
differential pressure drop across the filter. An explosion-proof
switch is required since this inherently safe motor design is
used to drive gas compressors. If the filter pressure drop
reaches a preset high limit, the switch shuts down the motor
and signals an appropriate alarm.
A Dwyer DCT1000 Dust Collector Timer Controller with attachable DCP pressure sensing module monitors and controls the
dust levels and corresponding pressure drop across the filter
bags. The DCT1000/DCP control automatically activates the
cleaning cycle when the DCT1000's pre-programmed set points
have been exceeded. This on-demand control system alleviates
excessive air compressor usage by preventing unnecessary
cleaning which lowers energy and maintenance costs.
22
pg 23
12/10/03
6:55 PM
Page 1
pressure
Minihelic® II
Gage
Magnehelic® Gage
Filter Bank
Inlet
Duct
Blower &
Controls
Differential pressure gage monitors filter loading in
asbestos removal negative air system.
Military flight line air-conditioning system utilizes a
Dwyer gage to monitor filter condition.
Makeup Air
Capsu-Spirahelic
Gage
Filter Unit
HI
HI
LO
Magnehelic® Gage
Shut-Off Valves
HI
Line Valve
MarkIIII
Mark
Manometer
Manometer
Shut-Off Valves
In pressurized hospital rooms, a Dwyer manometer
reveals pressure while a Dwyer gage monitors air
filter.
Flow
Filter
Hospital patients who are susceptible to dust or bacteria require
the services of an “environmental care unit.” Sophisticated air
filtration systems remove particulates from the incoming pressurized air. A Magnehelic® differential pressure gage monitors
the pressure drop across the filter system to indicate when
maintenance is necessary. The Dwyer Mark II manometer monitors positive room pressure to insure that adequate pressure
above atmospheric will prevent an influx of unfiltered air when
the doors are opened. If a dial type readout is desired, a
Magnehelic® or Minihelic® differential pressure gage can be
used in place of the Mark II manometer. Or, to provide a visual
or audible warning of impending problems, Photohelic®
switch/gages can be installed to serve both applications.
High pressure gage monitors condition of pipeline
liquid filter.
In a typical high pressure liquid filter installation, a clean filter
element will have a rated pressure drop for a given operating
line pressure and rate of flow. As the filter accumulates particulate, the resistance to flow increases and the pressure drop
increases until the level is reached when the filter element must
be cleaned or replaced. The Capsu-Spirahelic gage will indicate
the differential pressure across such filters up to 100 psig. The
by-pass piping and valving permit changing either the filter or
the gage without shutting down the system.
23
control
Removal of asbestos material from buildings requires careful
containment of airborne fibers generated during the removal
process. The work areas must be sealed off and maintained at
a negative pressure compared to atmosphere to prevent the
escape of fibers from the work area. The negative pressure air
system illustrated above is portable and contains a HEPA filter
to remove the asbestos fibers from the “suction” duct prior to
exhausting the resulting clean air outside the work space. A
Minihelic® II differential pressure gage is utilized to monitor the
pressure drop across the filter bank and indicate when cleaning
or replacement is necessary. A Series 1910 differential pressure
switch is also sometimes used in parallel with the gage to activate a filter alarm lamp mounted on the system control panel.
The extensive avionic systems on modern military aircraft
require cool, conditioned air to remove heat generated by this
equipment. In flight, the cooling air needs are met by the ambient air at higher altitude. However, during pre-flight maintenance, the high volume of cooling air must be supplied by easily transportable air conditioning systems like the unit illustrated
above. Critical monitoring of the condition of the air must be
supplied by easily transportable air conditioning systems like the
unit illustrated above. Critical monitoring of the condition of the
air filters used on these portable systems is provided by the
Dwyer Magnehelic® gage. The Magnehelic® gage easily meets
the reliability and ruggedness requirements of this application.
pg 24
12/10/03
6:56 PM
Page 1
pressure/flow
Model CS-150
Pressure Switch
Saw
Pump
Miniature pressure switches ensure safe
electronics in spas and hot tubs.
Lube Oil Tank
Control panels on hot tubs and spas must have their electronics
completely isolated from any point where water could enter the
system; however, control buttons must be easily accessible for
proper operation. To accomplish this, pneumatic buttons are
used, which when depressed, transfer a pressure through a tube
to a Dwyer MDA or MDS Miniature Pressure Switch. When the
switch senses the pressure, the circuit closes, sending a signal
to the control panel to perform the intended function. As such,
electronic components can be located in a safe, water-free area
of the system.
control/air/gas
Mercoid® model CS-150 pressure switch senses
loss of lubricating oil to saw blade in saw mill and
actuates an alarm.
Since only a small amount of oil is used, the sawdust can be
recovered and used as a fuel. The pressure switch (CS-150)
sounds an alarm if the oil pressure is lost, preventing severe
damage to the saw blade.
Differential
Pressure Switch
LO
HI
Differential
Pressure Switch
Static Pressure Taps
Flow
Exhaust Duct
Radio
Broadcast
Transmitter
Dwyer differential pressure switch monitors fan
operation.
Dwyer switches protect electronic equipment
should cooling air flow fail.
Where it is necessary to prove operation of an exhaust fan, a
Dwyer differential pressure switch performs well. The simplest
technique requires connecting only the high pressure switch
port to a static pressure tap downstream from the fan, if the fan
is located at the beginning of the duct, or the low pressure port
upstream from the fan if the fan is located at the end of the
duct. The switch senses the slight pressure created by the fan
compared to the atmosphere. If the fan is located somewhere
within the duct, we recommend placing sensors ahead and
behind the fan, as shown above. This takes advantage of the
higher pressure differential across the fan to operate the switch.
In all three cases, if the fan stops, the switch will signal a warning or start auxiliary equipment.
Dwyer differential pressure switches are specified to prove the
existence of sufficient cooling air flow in electronic equipment.
Large final amplifier tubes in broadcast radio transmitters
require essential cooling air or overheating will quickly damage
these expensive components. A total pressure pick up placed in
the cooling air stream and connected to the pressure switch
can instantly sense any drop in total pressure due to fan failure
or air blockage. It will then sound an alarm or shut down the
amplifier before failure occurs or temperature sensors cause a
less desirable shutdown.
24
pg 25
12/10/03
7:00 PM
Page 1
flow/air velocity
Magnehelic® Gage
HI
Durablock®
Inclined Manometer LO
Computer
Unit
HI
Supply
Air
LO
Static Pressure Tap
Motor
Control
Air Flow
Pitot Tube
Air Flow
Fan
Variable
Speed
Motor
Total
Pressure Sensor
Series 641
Air Velocity
Transmitter
Dwyer transmitter signals precise air velocity
adjustments to computer-controlled variablespeed fan motor.
In variable air volume (VAV) HVAC systems, a computerized
control provides precise adjustment of air volume to meet
changing system needs with maximum energy efficiency. The
Dwyer Series 641 has an optional LED display for local indication of air flow. The LED display provides a quick, visual
acknowledgement of proper system performance. The computer reacts to any change in velocity by signaling the motor control to increase or decrease fan speed to maintain the required
velocity. The computer, taking inputs from other ambient condition sensors, will establish a new required air velocity and signal
an appropriate adjustment in fan speed.
Magnehelic®
Gage
Differential
Pressure Switch
Fume Hood
HI
NORMAL
LOW
LO
HI
Model 660
Air Velocity
Monitor
Static Pressure
Tips
Air Flow
Air Flow
Evaporator
Dwyer switch senses ice build-up on cooling coils
and actuates defrost cycle.
Ensure proper ventilation by continuously
measuring fume hood face velocities.
In this cooling application, the Dwyer differential pressure
switch senses the increasing restriction to air flow caused by
icing and actuates the defrost cycle. Two static tips are installed
to sense the differential pressure across the cooling coils. In a
low cost, low voltage and current, high volume product application, the Dwyer Minitactor® differential pressure switch is an
economical unit to specify for this type of application. Dwyer
offers six types of stainless steel static tips to suit any application. In service applications, the Dwyer Trail-Tail® static pressure sensor serves to take accurate static pressure measurements, as it automatically aligns with duct air flow. The TrailTail® sensor, when attached to a length of light tubing, can also
be used to take measurements downstream from the point of
access to the duct.
The Dwyer 660 Air Velocity Monitor continuously measures
fume hood face velocities to ensure proper ventilation in accordance with safety standards. An audible and visual alarm alerts
the user when the lowest allowable safe operating limit of the
fume hood has been reached. The 660 has an adjustable low
limit range of 0-150 FPM (0-0.792 m/s) which allows the alarm
point to be set in accordance with the proper agency safety
standards. These cabinets often feature a Magnehelic® differential pressure gage on the control panel to monitor static pressure in the system as a check on proper blower operations and
to monitor pressure drop across the filter to indicate when the
filter should be serviced or replaced.
25
air/gas
Either of two methods used to measure air
velocity.
To measure air velocity, connect a Dwyer Magnehelic® or
Minihelic® differential pressure gage, or a Dwyer Durablock®
inclined manometer to a Pitot tube in the air stream as shown.
The alternative method at right requires only a static tap plus a
simple tube in center of duct to pick up total pressure. The differential pressure reading on the gage or manometer is velocity
pressure, which may be converted to air velocity by calculation
or reference to conversion chart. Where air density is known, the
gage manometer can also be calibrated directly in velocity units.
If you need an alarm or control function to maintain a preset air
velocity limit, install a Photohelic® switch/gage. Dwyer stainless
steel Pitot tubes are made in numerous lengths and configurations to serve in the smallest to the largest duct size.
pg 26
12/11/03
8:11 AM
Page 1
flow/air velocity
Cable Air Supply Lines
Multi-Column
Visi-Float®
Flowmeter
Rate-Master®
Flowmeter
Control
Panel
Test Valves
Dry Air Supply
Manhole
Air
Compressor
and
Dryer
Underground Cables
Flowmeters used to check dry air flow protecting
cables.
Air delivery source for telephone cables monitored
by Dwyer flowmeters.
Underground telephone cables are kept under pressure with dry
air for protection of the electrical circuits against damage due to
moisture. The flow of air to each cable is monitored to determine proper protection as well as to detect leaks that may develop due to cable damage. Special multi-column Dwyer Visi-Float®
flowmeters are widely used in this application. A manifold bored
in the flowmeter bank connects the supply air to the bottom of
each flowmeter through an on-off valve located in each bore.
The outlet of each flowmeter then feeds a single cable.
air/gas
Telephone cables, both overhead and underground, are pressurized with dry air to increase the reliability of communications by
protecting the cables from moisture. This compressor/dryer
system utilizes a Dwyer RMB Series flowmeter to indicate the
percentage of total system air capacity being delivered to the
cable routes connected to the dryer.
Differential
Pressure
Switch
Clear Plastic Cover
LO
Static
Pressure Tap
Visi-Float®
Flowmeter
HI
Heater
Bubbler
Column
Air Flow
Fan
Test Tank
Controls
Salt corrosion test cabinet includes a Dwyer
flowmeter for adjustment of bubbler air flow.
Total
Pressure
Sensor
Dwyer switch protects duct heater if air flow fails.
Sensing total pressure (velocity plus static), the Dwyer
Differential pressure switch in this application turns off the duct
heater to prevent burning out the heating element if the air flow
across the element becomes insufficient. In some cases, it may
be necessary to sense the negative static pressure upstream
from the fan (dotted lines) to develop a large enough differential pressure signal to operate the switch reliably.
Prior to atomizing a heated salt solution to produce a fog inside
this corrosion test cabinet, compressed air is bubbled through
a heated water column to properly heat and humidify the air. A
Dwyer Visi-Float® VFA flowmeter, as part of the system, provides precise adjustment of the bubbler air flow to meet test
standards.
26
pg 27
12/11/03
8:13 AM
Page 1
flow/air velocity
Differential
Pressure
Switch
LO
Air Supply
Actuator
HI
Setpoint
Controller
Series 641
Air Velocity
Transmitter
Flow
Probe
Oven Hood
Conveyor Drying Oven
Product
Conveyor
Air velocity transmitter controls drying oven air
flow.
If oven air flow fails, a Dwyer switch stops the
process.
The flow of heated air is held to a constant predetermined velocity in this carefully controlled low temperature process drying
oven. The constant temperature air supply is modulated by a set
of inlet louvers operated by a servo-driven actuator. A Dwyer
Series 641 Air Velocity Transmitter has an optional LED display
for local indication of air flow. The LED display provides a quick,
visual acknowledgement of proper system performance. The
controller compares the Series 641’s signal to the setpoint in the
controller and continuously signals appropriate louver adjustments to the actuator.
In this conveyor fed oven, a differential pressure switch monitors the pressure increase across the fan to assure maintenance
of proper air flow. The switch signals a warning or stops the
process upon failure of the fan. A second differential pressure
switch in parallel - and set for a higher pressure - can provide
more complete protection by sensing the greater pressure drop
that would result from blockage of the air intake. To add a capability for continuous visual monitoring by the operator, install
Dwyer Photohelic® switch/gages for these functions.
air/gas
Inlet Cyclone
Dwyer Model 530
Air Flow Switch
Control Panel
Electronics Section
Air In
Flow
Mini-Master®
Flowmeter
Blower
Gas Supply
Normally
Closed
Solenoid
Valve
Air Moving
Section
Preheater
Battery Pack
Optical
Section
Air flow switch protects preheater from
overheating.
Operator uses Mini-Master® flowmeter to verify air
flow into portable dust monitor.
Dangerous overheating would occur in this gas-fueled air preheater if the blower fails or the air flow is obstructed. To protect
against this condition, a Dwyer Model 530 air flow switch wired
to the gas supply solenoid valve will close the valve if the air
flow fails. A normally closed solenoid valve is specified to provide for fail-safe operation of this protective system. Where
hazardous ambient conditions exist, a W.E. Anderson® Model
V4 Flotect® explosion proof flow switch can also be used. In
addition, a Mercoid® Model M-51 temperature switch can be
used to monitor preheater temperature.
The small size, accuracy, and low cost of the Dwyer MiniMaster® Series flowmeter lends itself perfectly to use in this
portable, battery-operated dust monitor. Using a light scattering
electronic sampler, a small vacuum pump draws air through the
flowmeter into the sampling chamber, and the flowmeter verifies the proper volume of sample air flow. Readout is digital and
directly in dust weight per cubic meter of air.
27
pg 28
12/11/03
8:14 AM
Page 1
flow/air velocity
Pickup Unit
Total Pressure Tips
Office
Static
Pressure Tips
Air Flow
HI
Factory
Mark II
Manometer
Dwyer
Wind Speed
Indicator
air/gas
LO
Dwyer Wind Speed Indicator is widely used in
homes, offices, factories, marinas and farms.
Permanent stations indicate air velocity round the
clock.
The Wind Speed Indicator is a low-cost but durable unit for
measuring wind speed. It includes a remotely located indoor
readout instrument. It incorporates a simple, roof-mounted
Pitot-tube type sensor and a low-cost inclined-vertical manometer. No electrical power is needed - neither external, wind generated or battery. Solidly made, the Wind Speed Indicator has
been known to continue functioning in extreme wind and weather that destroyed other mechanical-electrical devices. Wherever
the velocity of the wind in either MPH or KPH is required - at
home, office, factory, farm or remote sites - the Wind Speed
Indicator is highly useful.
The efficient operation of heating and air conditioning systems
depends on delivery of balanced, pre-determined air flow.
Permanent measuring stations installed in the ducts enable
plant engineers to locate and correct problems before they
affect efficiency. Such stations can use low-cost Dwyer Mark II
manometers to indicate velocity pressure directly as the differential pressure between averaging total and static pressure tips.
The manometer is calibrated directly in CFM, as the duct area of
the station is known. A dial type Dwyer Magnehelic® differential
pressure gage can be used as an alternative if preferred.
Metering
Valve
Durablock®
Inclined
Manometer
Sample Analyzer
Sample
In Take
Dwyer Model
1230 Well-Type
Manometer
Flowmeter
Engine component test flowbench utilizes
precision Dwyer manometers to measure test
pressures and air flow.
Vacuum Pump
Metering valves on Dwyer flowmeters control
air/gas intake on permanent air pollution
analyzers.
This self-contained flowbench is used to test internal combustion engine components such as cylinder heads, intake manifolds, throttle bodies, air cleaners, etc., for design changes to
achieve maximum air flow and minimum pressure drops
through critical flow passages. Flow changes as small as 0.5%
can be measured. A Durablock® inclined manometer, indicating
percent of flow, is utilized in conjunction with individualized calibration charts to determine air flow in CFM. Two 48˝ Model
1230 well type manometers are also employed, one to set and
monitor test pressure and the other one for port mapping or
auxiliary use. These Dwyer manometers offer the necessary
resolution and accuracy to determine the effects of small
changes in engine design needed to achieve maximum performance.
Regulations regarding air pollution levels require continuous
monitoring a source and ambient pollutants in areas where
noxious gases are generated. Ambient air quality samplers utilize either Visi-Float® or Rate-Master® flowmeters to establish
the proper flow of sample or carrier gases into the analyzer. Top
mounted metering valves are recommended for flowmeters
used in vacuum service to maintain specified accuracy.
28
pg 29
12/11/03
8:23 AM
Page 1
flow/air velocity
Visi-Float®
Flowmeter
Vent
Sensor
Inclined
Vertical
Manometer
Gas Sampling Unit
From
Gas
Stream
Metering
Valve
Flue Gas Velocity
Pitot Tube Connection
To Control/Indicating
Unit
®
Portable sampler includes Durablock manometer
for accurate measurement of stack gas velocity.
Stack sampling regulations aimed at compliance with air pollution standards as well as the practical need for energy conservation require the use of many different instruments to make the
appropriate measurements. A special Dwyer Durablock® dual
column inclined/vertical manometer is used in the control unit of
a portable particulate sampler which can perform all the
required tests and measurements. While the illustration above
does not fully represent the complexity of this instrument, the
manometer’s primary function is accurate measurement of the
gas velocity in conjunction with a Pitot tube assembly in the
stack probe.
Instrument for monitoring dew point in gas streams
uses flowmeter with metering valve to control gas.
A chilled-mirror sensor system provides a continuous monitoring of dew point in various gas streams or humidity chambers.
The sample flows into the sensor under pressure with the proper flow rate set by the metering valve on the Dwyer Visi-Float®
flowmeter.
air/gas
Visi-Float®
Dual Column
Flow
Chamber
Patient Mask
Visi-Float®
Flowmeter
N2O
Tank
Controls
O2
Tank
037
Designers of a bio-medical incubator rely on a
Dwyer flowmeter to control CO2 flow.
Durable dual-column flowmeter adds value for
physicians and oral surgeons.
This low temperature incubator with CO2 atmosphere is used in
bio-medical applications, such as short term blood work and
long term tissue culture studies. CO2 is introduced at a high initial purge rate controlled by a timer. After the purge period, a
Dwyer Visi-Float® flowmeter with a metering valve is utilized to
adjust and monitor the CO2 flow in cubic centimeters per
minute. The Visi-Float® flowmeter provides the reliability and
accuracy needed to complement the host of high performance
features designed into this incubator.
Physicians and oral surgeons who use anesthesia or analgesia
in their offices on an occasional basis require a system that is
reliable but small and portable. One such system employs special Dwyer dual-column Visi-Float® flowmeters to meter and
monitor precise flows of nitrous oxide and oxygen to the
patient. In addition to meeting the performance level demanded
by this application, the Visi-Float® flowmeters are durable and
attractive complements to this important and visible medical
device.
29
pg 30
12/11/03
8:24 AM
Page 1
flow/air velocity
Decorator Cabinet
Housing Concentrator
Visi-Float®
Flowmeter
Metering
Valve
Air Control
Tip
Visi-Float®
Flowmeter
Irrigation
Tip
air/gas
Oxygen to Patient
Oxygen concentrator replaces heavy tanks and
includes Dwyer flowmeter for easy adjustment of
oxygen flow.
Designers of a medical irrigation unit specified a
Dwyer flowmeter to control heated or cooled air
flow.
Eliminating the need for cumbersome oxygen tanks, an oxygen
concentrator delivers oxygen to the patient from the surrounding air. This is a great convenience and cost savings for those
who frequently require oxygen at home. A Visi-Float® or RateMaster® flowmeter with a metering valve is placed in the oxygen
output line, so the patient can easily adjust the flow to the prescribed level.
Heated or cooled air is used for irrigation in certain medical procedures. Precise control of air flow, temperature, and time is
required. The manufacturers of a device to provide this service
rely on a Dwyer flowmeter to adjust and monitor air flow to the
irrigation tip from the pump located in the unit.
Mini-Master®
Flowmeter
Visi-Float®
Flowmeters
Leak
Indicator
Probe
Ventilator
Control Unit
To Patient
Small Dwyer flowmeter reveals proper suction flow
into portable halogen leak detector.
Metering valves on Dwyer flowmeters control precise mix of oxygen and air for infant ventilator.
This portable detector pinpoints halogen leaks as the operator
probes suspected areas and observes the leak indicator. A MiniMaster® flowmeter provides a low-cost means of continuously
checking that proper suction flow is maintained by an internal
pump, so that leaks do not go undetected due to obstruction of
the probes or failure of the pumping system.
Dwyer Visi-Float® flowmeters are specified to monitor and control the mixture of oxygen and air supply by an infant ventilator.
Special scales and oxygen cleaning customize the flowmeter to
this application. The built-in metering valve allows precise setting of flow for each gas.
30
pg 31
12/11/03
8:31 AM
Page 1
flow/air velocity
From Oxygen Supply
Switchbox
Differential
Pressure Switch
Housing
Motor
Generator
Mini-Master®
Flowmeter
LO
Rate-Master®
Flowmeters
HI
To Face Mask
Purge Gas Supply
Needle Valve
Flowmeters and/or differential pressure switches
monitor vital purge gas flow to motors, switchgear,
instruments.
Oxygen supply in small aircraft controlled by a
compact Dwyer flowmeter.
The Mini-Master® flowmeter is ideal for this small in-line oxygen
flowmeter used to set and indicate proper flow of oxygen to
pilots and passengers flying at higher altitude in small aircraft.
To conserve oxygen and reduce the drying effect of excess oxygen on the nose and mouth, the exact required flow can be set
using this device. The user simply holds it in a vertical position
and adjusts the needle valve on the Mini-Master® flowmeter for
a float position equal to the flight altitude. The needle valve and
flowmeter connections are contained in the small housing. The
entire unit can hang from an overhead oxygen outlet by the connecting tubing or dangle in any position after proper flow has
been set.
Rate-Master®
Flowmeters
Furnace
Visi-Float®
Flowmeter
Control Panel
Conveyor
Humidifier
Metering
Valve
From Oxygen
Source
Flows of air and gases used in a special furnace
are controlled by Dwyer flowmeters.
Oxygen to Patient
A total of eleven Dwyer Rate-Master® flowmeters function in the
design of this sophisticated conveyor belt furnace used in manufacturing electronic devices. The flowmeters provide precise
adjustment and monitoring of the flows of air and gases into
the various portions of the furnace, which allow it to perform
different operations, such as decarburizing and oxidizing,
metallic package sealing, glass package sealing, and glass-tometal sealing.
At-home patients can set metering valve on a
flowmeter to deliver needed flow of humidified
oxygen.
A portable device that meters and humidifies oxygen required
by a patient at home also provides convenience of movement
away from the oxygen source. A Visi-Float® flowmeter with a
metering valve allows the patient to see the prescribed flow.
This flowmeter’s small size and light weight, as well as its smart
appearance, make it well suited to the portability requirements
of this device.
31
air/gas
To purge motors, generators, switchgear, and industrial instrument cases, Dwyer flowmeters are installed in the supply line to
indicate a flow of air, manufactured inert gas, or nitrogen to
these devices. The flowmeters (with valves) allow maintenance
personnel to set the flow quickly and recheck anytime to make
sure proper flow continues. A Dwyer differential pressure switch
can also be used to monitor proper flow on a continuous basis
and provide a signal or alarm if purge gas flow fails. Such an
optional switch is shown above, monitoring proper flow of
purge gas to the switchbox as a function of pressure drop
across the flowmeter. The purging of electrical equipment in
hazardous areas may require more extensive control and monitoring devices.
pg 32
12/11/03
8:32 AM
Page 1
flow/air velocity
Digital Display
Air In
Duct
Air Out
Filters
Visi-Float®
Flowmeter
Series 471
Digital Thermo-Anemometer
Recorder
Determine air velocity and temperature levels in
ducts or air supply grills.
The Dwyer Series 471 Digital Thermo-Anemometer is the ideal
portable product for determining air velocity and temperature
levels in ducts or air supply grills. The 471-1's versatility is due
to its four field selectable ranges from 0-500 fpm (0-3 MPS) up
to 15,000 FPM (70 MPS). With a push of a button, FPM and
Fahrenheit readings are converted to MPS and Celsius.
Readings may be stored and retrieved which allows the user
greater efficiency with HVAC balancing at various locations in a
building.
Model 471-2 has an extendable probe and model 471-3 provides a bendable extending probe for hard to reach sampling
locations.
air/gas
Patient breath sampler uses Dwyer flowmeter to
adjust flow rate of expiration breath sample.
Continuous monitoring of the CO2 in the expiration breath of a
patient in intensive care or under anesthesia provides a rapid
indication of changes in metabolism due to respiratory or circulatory problems. The designers of this monitoring device specified our Visi-Float® flowmeter to permit adjustment of the proper breath sample flow rate induced by a vacuum pump in the
monitor.
Magnehelic® Gage
HI
HI
Magnehelic®
Gage
LO
Static Pressure Taps
Flow
Duct
Air Flow
Orifice Plate
Nozzle
Egg Crate Staightener
Measuring air velocity with an orifice plate.
Measuring velocity or volume of air flow in duct.
In this set-up, the Magnehelic® gage measures higher air velocities as a function of the pressure drop across a sharp-edged
orifice plate in the pipe. The pressure drops can be converted to
air velocity using orifice plate data supplied by the manufacturer. Details regarding available sizes, ranges, installation, and
limitations are available from orifice plate manufacturers and
from standard handbooks. A Dwyer Durablock® inclined
manometer or Photohelic® differential pressure switch/gage
can also be used. In addition to the visual reading gage, the
Photohelic® switch/gage provides an alarm signal or shutdown
control function. Pressure sensing taps should be located on
the side or top of the pipe or duct to prevent condensation from
draining into sensing lines or gages.
A small flow nozzle with an egg crate air straightener located
upstream in a large duct provides an accurate, easily constructed air velocity measurement system. Air velocity distribution at
the point of discharge across the outlet of nozzle is uniform, and
static pressure is zero (atmospheric). Consequently, in the low
flow area upstream from the nozzle, static and total pressure at
nozzle outlet. As a result, the air velocity and/or volume of flow
is easily calculated. The Dwyer Magnehelic® differential pressure
gage or manometer can be calibrated to read air velocity or volume directly - assuming standard or constant air density (i.e.
temperature, humidity, and pressure). A Photohelic®
switch/gage can be used if an alarm or control function is
required at a given air velocity or volume.
32
pg 33
12/16/03
4:00 PM
Page 1
flow/air velocity
Blended Gas
Food Perishables
Preservation
Air Flow
Series MTF
Series MVT
O2
CO2
N2
Handheld anemometer enables traversing duct
flow measurements with a miniature vane and
telescoping probe.
Enable accurate metering of gases in preservation
of food perishables with Dwyer Multitube Flow
System.
Series PFS
Smart Air
Velocity
Transmitter
Ice Cream
Air Flow
Nitrogen
Series GFC
Eliminate the need for Pitot tubes, static pressure
tips, orifice plates and differential pressure sensors
with a Smart Air Velocity Transmitter.
Provide simple, accurate flow control of various
gases for many applications with a Gas Mass Flow
Controller.
Installing air velocity measurement systems can be a burdensome process – specifying Pitot tubes, static pressure tips, orifice plates, differential pressure transmitters, etc. Dwyer offers
the PFS Smart Air Velocity Transmitter to consolidate these
components into one convenient instrument. The PFS can be
easily installed into the duct or air stream to accurately measure air flow while providing local indication as well as linear
analog output. Microprocessor-based technology ensures
accurate, repeatable results while state-of-the-art software
allows for volumetric calculations and datalogging functions.
The PFS combines these features for simple, reliable airflow
measurement without the problems associated with complex,
traditional systems.
Dwyer GFC Gas Mass Flow Controllers are ideal for numerous
applications where high accuracy gas flow control is required.
Ice cream producers must generate an exact 50% air-to-cream
ratio in order to comply with federal regulations. The GFC can
measure the mass of air injected into the mixture, freeing operators from lengthy and potentially inaccurate procedures
involving volumetric meters with manual valves. Dwyer GFC’s
are equipped with precision valves which can be controlled
locally by an operator or remotely using industry standard analog signals. The controller also outputs an analog signal proportional to the flow rate for remote monitoring purposes.
33
air/gas
Handheld anemometers are an excellent, portable tool for performing tests on HVAC system performance; however, large
rotating vanes can prevent easy access to ducts. Dwyer introduces the MVT Mini-Vane Thermo-Anemometer to eliminate
this problem. With its 1/2˝ diameter vane, the MVT simplifies
probe entry into the duct. Traversing measurements, which are
difficult or impossible with other anemometers, are made easy
with the MVT’s telescoping, extendable probe. Additionally,
simple keypad programming enables the user to view volumetric flow rates in CFM or CMM. Datalogging software is also
available to easily record and view data on a PC or laptop.
For blending or metering different gases, Dwyer’s MTF Multitube
Flow Systems are some of the industry’s most reliable and
requested products. Food packaging is one of many applications which require precise mixing of several gases. Oxygen,
N2, CO2, and other gases are blended and injected into the packaging of perishable products to optimize the shelf life. The gas
mixture replaces the previously evacuated air, providing the necessary preservation. By merging high precision valve technology with flowtubes that can be correlated to almost any gas, the
proven design of the MTF imparts accurate gas measurement
and control.
pg 34
12/11/03
8:35 AM
Page 1
flow/air velocity
Alarm
Valve
Bleed Fittings
Capsu-Photohelic®
Switch/Gage
Flotect® Switch
Engine
LO
HI
Electrical Lead to
Control Room
Indicators
Heat
Exchange
liquid
Zero-center switch/gage on pipeline signals flow
direction to remote control room.
If cooling water flow fails, Flotect® flow switch
sounds alarm or stops engine.
When used with water or other compatible liquids, a brass body
Dwyer Capsu-Photohelic® differential pressure switch/gage
serves as a simple, reliable flow direction monitor. It will signal
flow direction in a pipeline at a remote location, such as in a control room. Taps in the wall of the pipe on each side of a conveniently located valve provide a method to indicate a small pressure drop due to a slightly restricted flow even when the valve is
fully open. A low range zero-center Capsu-Photohelic®
switch/gage registers flow in one direction as an upscale reading and opposite flow as a downscale reading. With the setpoints adjusted each side of zero and consistent with the pressure drops involved, the switch/gage relay closure provides the
required control of the flow direction indicators.
To insure the vital flow of cooling water to a large engine, a W.E.
Anderson® V4 Flotect® flow switch can be placed in the cooling
water line. It will sound an alarm if the flow falls below a safe
minimum, or can even be connected to shut off the engine.
Cooling Tower
Flotect® Switch
Alarm
Flotect®
Switch
Gate Valve
Circulating
Pump
Air Conditioning
Unit
Pump
Check Valve
Condenser
Flotect® flow switch ensures cooling water
circulation before air conditioning compressor
motor starts.
One of many options, a Neoprene boot over
Flotect® flow switch vane hinge protects it from
buildup of solids.
Large air conditioning and refrigeration systems which include
water cooled condensers require that the water must circulate
through the condenser and cooling tower in sufficient volume
before the compressor is started. Here the W.E. Anderson®
Flotect® flow switch is connected to the compressor control circuit to prevent starting or to shut down the compressor control
circuit if the flow of cooling water falls below that required for
proper operation. A dual Flotect® switch (available as an option)
will also trigger a remote alarm to signal the operator of the
shutdown as soon as it occurs.
This W.E. Anderson® V4 Flotect® flow switch has an optional
Neoprene boot (inside the pipe) to protect the vane hinge from
an accumulation of solids. Installed on a storm sewer lift pump,
the switch will stop the pump motor when flow ceases or falls
below the set minimum, preventing pump cavitation and wasted power.
34
pg 35
12/11/03
8:39 AM
Page 1
flow/air velocity
Storage Tank
Flowmeter
Mixture Out
Metering Knob
Midwest
Sight Flow
Indicator
Shut-Off Valve
Pump
Valve
Mixing Tank
Portable
Tank
Concentrate
Water Supply
W.E. Anderson® Midwest Sight Flow Indicator
reveals flow or stoppage.
When adding a chemical concentrate to a large volume of water
or other fluid, you can determine the rate at which the concentrate is being added by using either a Dwyer Rate-Master® or
Visi-Float® flowmeter. The concentrate is added on the input side
of the pump. This draws the concentrate from its container and
also utilizes the mixing action of the pump. While a metering
valve is built into the flowmeter, a separate valve permits complete shut-off of the concentrate flow, if necessary, without disturbing the flow rate setting. Typical applications of this set-up
include adding medicine to livestock water and detergent to
pressure washers or car wash installations. Concentrates must,
of course, be compatible with the plastics used in the flowmeter
bodies.
In this gravity feed system delivering liquid fertilizer to portable
tanks, a Midwest Model 100 sight flow indicator was installed.
The operator can see the rotating vanes to check for adequate
flow at any time.
liquid
Flowmeter controls flow rate of a chemical
concentrate.
Alarm
Water Supply
Flotect® Switch
Condenser
Valve
Controls
Boiler
Flowmeter
Shower Head
Operators of this laboratory still use the metering
valve on a Dwyer flowmeter to set desired feed
water flow.
Use of this emergency industrial shower automatically actuates W.E. Anderson® Flotect® flow switch
which sounds alarm to bring help.
This compact automatic distilling unit provides a small, but
continuous supply of ultra-pure water for laboratory use. Using
a Dwyer Visi-Float® flowmeter with a metering valve, the operator sets the proper boiler feed water flow consistent with lab
requirements up to the rated capacity of the still in liters per
hour. When the distillate receiver is full, a level sensor actuates
a solenoid valve which shuts off the feed water flow. A RateMaster® flowmeter can serve equally well in this application.
In this emergency industrial shower, a V4 Flotect® flow switch
has been mounted in the water supply pipe. It will activate
either an audible or visual alarm (or both) to summon help
when the shower is used by an employee who has been accidentally contaminated by hazardous material.
35
pg 36
12/11/03
8:50 AM
Page 1
flow/air velocity
Flotect® Switch
Supply
Rate-Master®
Flowmeter
Return
Chlorinator
Metering Valve
Check Valve
Heater
Main Pump
To Pool
Pump
From Pool
Filter
Standby Pump
Flow of filtered water to pool chlorinator controlled
by metering valve on economical Dwyer
flowmeter.
Check Valve
Check Valve
Proper metering of the amount of chlorine added to swimming
pool water is necessary to avoid irritation to the swimmer and
excessive cost due to using too much chlorine. It also ensures
sufficient flow to maintain proper sanitation. A Rate-Master®
flowmeter provides a low cost but rugged metering device for
this application. Filtered water is tapped from the main pool supply pipe and delivered to the chlorinator at the proper flow rate
by the built-in metering valve on the Rate-Master® flowmeter. It
then returns to the heated pool water supply line. When using
plastic flowmeters such as the Rate-Master® Series for metering
chemical solution, try to locate the flowmeter upstream of the
chemical additive if possible. This will minimize compatibility
problems between the chemical and the plastic body of the
Dwyer flowmeter.
When main pump fails, Flotect® flow switch
transfers to standby pump to maintain vital fluid
circulation.
liquid
When proper fluid circulation in a system is critical, the W.E.
Anderson® Flotect® flow switch will automatically start a standby pump should the main pump fail. The flow in the main path
of the parallel system illustrated keeps the Flotect® flow switch
in an open position. When the main pump fails, the flow will
cease. The flow switch then closes, starting the standby pump.
Flow
Pipeline
Water
Sand
Stone
Pump
Cement
Capillary Tube
Bleed
Fittings
Capsuhelic®
Gage
LO
HI
Rate-Master® Flowmeters
Fuel oil viscosity in pipeline is visually indicated by
Dwyer gage or controlled by switch/gage.
Flowmeters on industrial mixers show flow of
special additives.
Continuous monitoring of fuel oil viscosity is required in some
combustion control systems. In this application, a constant
flow pump forces a sample of the fuel oil through a capillary
tube under temperature controlled conditions. A Capsuhelic®
differential pressure gage measures the pressure drop across
the capillary and, with the fuel oil at a constant temperature, the
gage can be calibrated to read viscosity directly. If automatic
viscosity control is desired, a Dwyer Capsu-Photohelic® differential pressure switch/gage will actuate appropriate valve openings and closings electrically.
This mobile concrete mixer transports the unmixed materials to
the job site and then prepares the concrete, delivering the exact
amount and the proper formulation required for the specific job.
On the control panel at the rear of the truck mounted mixer,
Dwyer Rate-Master® flowmeters permit setting the proper
admixture flows to add the specified quantities of accelerators,
retarders, air-entraining agents, etc.
36
pg 37
12/11/03
8:52 AM
Page 1
flow/air velocity
Capsu-Spirahelic
Gage
HI
H3 Differential
Pressure Switch
LO
LO
HI
Shut-Off Valves
Orifice
Plate
Line
Line Flow
Orfice Plate
Pressure switch monitors flow in high pressure
system.
A calibrated orifice plate located in a pipeline will create a pressure drop which can be measured up to 100 psig with a CapsuSpirahelic differential pressure gage. The pressure drop can be
read directly in psig or translated into flow units such as gallons
per minute, barrels per day, etc., and read directly on a specially calibrated scale designed to meet customer specifications.
In a liquid process high pressure line, the process may be
adversely affected by flows above (or below) the desired flow.
The W.E. Anderson® Model H3 can monitor flow in systems with
operating pressures up to 1500 psig as a function of pressure
drop across a calibrated orifice plate. The H3 set point is adjusted so that an alarm sounds or the process is automatically shut
down if flow exceeds (or falls below) the desired rate.
Brianair
W.E. Anderson®
V6 Flow
Switch
Normally Open
Normally Open
Chiller
150 psi
55° F
144 psi
45° F
H3 Differen tial
Pressure Switch
W.E. Anderson® H3 explosion-proof differential
pressure switch protects water chiller.
W.E. Anderson® flow switch protects aircraft deicing equipment.
This aircraft de-icer saves time and heating fuel by heating only
the fluid dispensed, not the entire tank. With the de-icing fluid
heated by three large heat exchangers operating in parallel, deicing can begin within 90 seconds regardless of ambient temperature. Three W.E. Anderson® Model V6 flow switches are
used to sense adequate flow of de-icing fluid through the heat
exchanger, one switch on each exchanger. Should fluid flow be
interrupted or drop below a safe level, the burner for the affected heat exchanger will shut down. The V6 flow switch is well
suited to this application because of its reliability and inherently weatherproof design.
If ice builds up inside water chiller, or if tubes become restricted, differential pressure across chiller increases. Differential
pressure switch Series H3 senses the increase and actuates an
alarm. Switch is typically set between 10 and 20 psid.
37
liquid
A differential pressure gage measures pipeline
pressure drop over orifice plate.
pg 38
12/11/03
8:54 AM
Page 1
flow/air velocity
Central
Vacuum
System
Wall
Outlet
Suction to Patient
Water Purifying
Reverse Osmosis
System
Series UV
Ultra-View
Polysulfone
Flowmeter
Metering Valve
TM
Visi-Float® Flowmeter
Container with
Disposable Fluid Bag
Ultra pure flowmeter for water purification
equipment.
liquid
Suction system that removes fluids from hospital
patients includes a flowmeter with top metering
valve.
The Dwyer Series UV Ultra View™ Polysulfone flowmeter is an
industrial, highly accurate flowmeter with excellent physical
properties and wetted parts. The Series UV possesses all plastic wetted parts which include polysulfone, Viton®, and PTFE.
There are no metal wetted parts that can possibly corrode over
time.
Best suited for water purification systems such as reverse
osmosis or de-ionized water systems, the Series UV monitors
water that is passing through the purifying membranes.
Depending on system size, rates may be a few GPM up to 40
GPM or more. Several ranges of the Series UV are available to
satisfy these various sizes.
Many hospital rooms are equipped with vacuum lines to provide
suction for removing fluids from patients. One disposable fluid
container system for use with these in-room suction outlets
employs a Dwyer Visi-Float® flowmeter with built-in top mounted metering valve. Using this valve, the attending nurse can set
the prescribed rate of suction flow for each patient’s need. This
eliminates the guesswork employed when the wall valve alone is
used for flow regulation. Often, the latter can result in either
insufficient suction to remove all fluid or tissue damage if too
much suction is applied. Top mounted metering valves are recommended for flowmeters used in vacuum service to maintain
specified accuracy.
Series SFI-800
Sight Flow Indicator
Series SFI-800
Sight Flow Indicator
Drum
Water
Tank
Series V12
Flotect® Flow
Switch
Outlet
Inlet
W.E. Anderson® Series SFI-800 and Series V12
indicate water flow in a concrete delivery truck.
W.E. Anderson® Series SFI-800 indicates water flow
in water treatment processes.
Ready mix concrete is delivered in a large truck with a rotating
drum that keeps the concrete from hardening. Also on the
truck is a tank for storing water that is used to keep the concrete at a proper moisture level. An SFI-800 sight flow indicator and transmitter is installed in the water line between the
water tank and the drum to monitor the amount of water added.
The SFI-800 has a pulsed output that can be used for flow rate
and flow totalization. A display in the cab of the truck allows the
operator to monitor the flow from the SFI-800. Also on the
truck is a hose line connected to the water tank, which is used
to clean the concrete chute and any spills at the construction
site. A V12 flow switch is installed in the hoseline to indicate
that water is flowing out of that line. The SFI-800 is perfect for
this application since it has a weatherproof transmitter package
that is removable and replaceable in the field.
The treatment system exposes water to UV (ultraviolet) light
that disinfects it. UV light has been shown to kill bacteria and
pathogens and has become a viable method for water treatment
that eliminates the need to use chemicals such as chlorine.
Incorporated into the design of the system is an SFI-800 to
monitor the flow rate of the water through the system. The SFI800 has a visual indication of flow and a linear voltage output
of flow rate used to control the flow. Controlling the flow
through the system is important to make sure the water is
exposed to the UV light the proper amount.
38
pg 39
12/11/03
8:55 AM
Page 1
flow/air velocity
Bleed Fittings
Flowmeter
Capsuhelic®
Differential
Pressure Gage
(Brass Option)
HI
LO
LO
Magnehelic®
Gage
Regulator
Flowmeter
Series DS-300
Averaging Pitot Tube
Regulator
Air/Gas Supply
HI
Flow
Water Flow
Orifice
Brass body gage measures water flow rates.
Purging orifice sensing lines with air permits use of
a Dwyer gage as an orifice meter on liquid pipe
lines.
Dwyer Magnehelic® differential pressure gages can be used as
orifice meters in corrosive gas or liquid applications by purging
the orifice with air or inert gas under pressure to protect the
gage from direct contact with fluid and also prevent clogged
meter lines. The gage is shown connected to two Dwyer flowmeters with constant differential pressure regulators supplying
purge air or gas to both the low pressure and the high pressure
tap lines. Our Photohelic® differential pressure switch/gage can
also be used to position motorized control valves using a null
band control mode, thus maintaining the proper rate of flow
through the pipeline for varying conditions.
Visi-Float®
VFA Flowmeter
Fuel
Liquid Out
Engine
Flotect®
Switch
Anderson®
Sight Flow
Indicator
Supply Tank
Pump
Heat
Exchange
Water
Flow
Pump
Fuel and cooling flow to large engines and compressors monitored by Dwyer flowmeter and W.E.
Anderson® Sight Flow Indicators.
W.E. Anderson® Flotect® switch stops pump when
flow stops.
By indicating flow of cooling water to engines, compressors
and other machinery, Sight Flow Indicators permit the operator
to monitor the proper flow to protect the equipment. Engine fuel
flow can be measured with a flowmeter. The Dwyer VFA
flowmeter series is compatible with and can monitor the low
flows encountered in fuel oil systems. W.E. Anderson® Flotect®
switches (not shown), when inserted in the cooling water lines,
can provide an alarm or system shutdown should the flow fall
below a safe limit.
When the liquid in this supply tank is exhausted, the W.E.
Anderson® V6 Flotect® switch senses the loss of flow and stops
the pump motor, preventing pump cavitation and saving energy.
39
liquid
A Dwyer brass body Capsuhelic® differential pressure gage,
required for water service to prevent corrosion damage to the
gage, is used in conjunction with a Dwyer Series DS-300 averaging Pitot tube. The Capsuhelic® gage provides a basic method
of measuring water flow rates. As a guide in selecting the appropriate Capsuhelic® gage range, the designer can consult data
provided with the DS-300 averaging Pitot tube. This relates differential pressure in inches of water column to the water flow in
gallons per minute for the pipe size involved. The gage can be
calibrated directly in GPM if desired. Bleed fittings installed in
the top ports of the gage are recommended to facilitate removal
of air from the system.
pg 40
12/11/03
8:57 AM
Page 1
flow/level
Chemicals/
Paints
Valve
Man ifold
Dwy er P-Series
Flow Switches
Valves
Filter
liquid
Coo ling Wate r
Supply Line
P-Series
Flow
Switch
Spray
Nozzle
Dwyer P-Series Flow Switches prevent overheating
of molds by ensuring water or coolant flow in
injection molding machinery.
Dwyer P-Series flow switches protect pumps and
ensure proper system operation in chemical and
paint spaying processes.
Plastic injection molding requires tight regulation of system temperatures to ensure perfect production. Overheating of molds is a
common cause of production shutdowns and can result in faulty
parts or even damaged molds. When installed into the mold cooling lines, Dwyer P-Series Flow Switches protect the expensive
equipment by ensuring flow. If flow drops below the required rate
or ceases entirely, the flow switches will enable system shutdown
or alert an operator of the urgent situation. The switches can also
ensure that water flow is turned on before the process begins by
preventing start-up procedures until adequate flow is reached.
Maintaining adequate flow rate is a critical factor in chemical and
paint spraying systems. If fluid flow is inadequate, surfaces may
not be covered evenly or efficiently. System pumps can also be
damaged when flow falls off. A Dwyer P-Series Flow Switch can
prevent these problems by indicating inadequate or fluctuating flow
rates. By inserting the switch into the control circuit, system operation will cease before the equipment is allowed to function improperly. P-Series Flow Switches are ideal for this type of application
because of their in-line design, high pressure limits, and easy installation and maintenance.
Mod el UF
Flotect®
Flow
Switch
Remote
Terminal
Unit
To Control Center
Mercoid®
Weatherproof
DA Series
Pressure Switch
Ground
Water
Pump
Chlorine F low
Water
Treatm ent
Flow
Water treatment facilities measure the flow rate of
chlorine non-invasively with ultrasonic flowmeters.
Flow and pressure switches protect large
municipal water system pumps from damage.
Flow measurement of chlorine is a critical process in water
treatment facilities. Using in-line flowmeters can prove to be
very difficult due to the corrosive nature of the liquid. A
portable Dwyer UF Ultrasonic Flowmeter can simply be
strapped onto the outside of a pipe to accurately measure the
flow rate of chlorine without ever coming into contact with the
substance. Since Dwyer’s ultrasonic flowmeters are easily
installed and removed in seconds, they can be used to measure
flow at different points in the process or even on completely different pipe sizes, eliminating the need for cumbersome fittings
and threaded connections.
Municipal water systems supplied by deep wells located at
many locations throughout the system require reliable alarms
at each pump in case of low suction or high discharge pressure
conditions. Many systems also employ a Flotect® flow switch
for added low suction alarm evidenced by low or no water flow.
Both switches signal alarms to a remote terminal unit at the
pumping location which, in turn, relays the alarm conditions
and location to the central water system control station. The
integral weatherproof construction of the Flotect® switch and
optional weatherproof DA switch housing allow these controls
to be located at outdoor pumping stations.
40
pg 41
12/11/03
9:01 AM
Page 1
level
Series MPC
Pump
Controller
Silo
Receiving Bin
Mercoid® pump
controller with
level transmitter
control pumps
in wastewater
lift stations.
Series PLS
Paddle
Level Switch
Transpor ter
Inlet
Outlet
Series PBLT
Level Transmitter
Submersible Pumps
Pneumatic conveying systems use air to transport powder
and dry bulk solids through conveying lines. The air is pressurized by positive pressure or vacuum to move the product
through the lines into and out of silos, transporters, and
receivers. Typical applications have high and low level indication in the storage bins to control the flow of product in or out.
The PLS is perfect for level use in these storage bins. It has
a rotating paddle that is inserted into the bin. As the product
level builds up in the bin it stops the paddle from rotating and
triggers the level output. The PLS is great for this application
as it not affected by pressure changes in the bin.
Vent
Control
Box
Duotect®
Pressure
Switch
Fill Pipe
L4
Float
Switch
Solenoid Valve
High Limit
Indicator Lamps
Pressure Tank
L4 Float
Switch
Control
Panel
L4
Float
Switch
Low
Limit
Well Pump
Switches control water level and tank pressure.
Drain
A hydro-pneumatic tank with a deep well pump maintains
desired pressure in a water system. The pump, however, delivers entrained air along with makeup water, requiring periodic
tank venting to prevent excess pressure buildup. As both water
level and tank pressure must be maintained, one side of the W.E.
Anderson® Duotect® pressure switch is interlocked with the W.E.
Anderson® L4 float switch via the control box. When tank pressure falls below the preset system pressure due to water drawdown, the Duotect® switch starts the pump and transfers control
to the float switch. When the preset water level is reached, the
float switch turns the pump off. If entrained air has increased the
pressure beyond the limit set in the other side of the Duotect®
pressure switch, after a time delay covering several normal
cycles, then the switch will open the solenoid valve and vent the
tank down to proper pressure.
Reliable float switches monitor and control liquid
level.
The W.E. Anderson® L4 float switch provides a simple, reliable
means for monitoring and controlling the level of a liquid in a
large tank. In this holding tank application, the lower L4 indicates to the operator that a tank fill cycle is required; the L4 can
also control the necessary valve or pump to provide an automatic fill cycle. When the level of the liquid reaches the upper
L4, the switch activates another indicator lamp or terminates
the automatic fill cycle. The L4 float switch in optional stainless
steel is recommended for level control of corrosive liquids,
while the lower cost standard brass L4 serves well in most
water and oil applications.
41
process/liquid
Lift stations are used to transmit wastewater to the treatment facility.
Wastewater is transmitted by gravity feed so it has to be continually
elevated to provide height to generate the flow. Lift stations are pits
located at points in the wastewater system to collect the wastewater
that usually have two submersible pumps. Wastewater in the lift station is pumped out to a higher level from where it can flow on to the
next lift station or to the treatment facility. The Mercoid® Series MPC
pump controller is used with the Series PBLT level transmitter to control the level in the lift station. The PBLT is a level transmitter that is
submersed in the tank and sends a linear output of the height of wastewater above it. The MPC takes the height input and controls the pumps
according to how it has been programmed. For a lift station, the primary pump comes on when the tank hits a high level and turns off
when the level decreases to the set low level. The second pump is used
if the first pump cannot drain the station and comes on at a set higher
level above pump 1. High and low level alarms, submersible pump seal
failure indication, pump over temperature protection, and pump alteration all are built into the MPC.
Proximity® Series PLS is used to indicate level status
in pneumatic conveying systems.
pg 42
12/11/03
9:02 AM
Page 1
level
Magnetic Diaphragm Bin
Level Indicators
Dip Tube Assembly
®
Proximity explosionproof Ultra-Mag™
level switches
provide powder
and bulk solids
level monitoring with
suspended (“S”)
or flange (“F”)
mounted models.
Pump
Paint Storage
Tank
High
Alarm
Fuel
Oil
Low
Alarm
liquid
Fuel oil and paint liquid level switch applications
require the Proximity® Sliquid™ pressure sensitive,
magnetic diaphragm switches with one, two, or
three precision switches.
S
High Level
Alarm
S
F
Low Level Switches
F
Low Level
Alarm
A magnetic coupling completely seals the switch(es) in the
housing from the product and environment, ensuring high reliability and enhanced safety. Alarm capability is depicted above.
Side mounted flange models are applicable for all bin levels.
Top-of-the-bin suspension-mounted models for high and intermediate point level provide improved sensitivity (in materials
with bulk densities as low as 5 pounds per cubic foot), and
enhanced vertical adjustment capability compared to flangemounted models. Elastomeric diaphragms are typically used in
products such as fly ash, plastics, grain, powders, foundry
sand, cement, aggregate, coal, metal chips, and glass. For pneumatic (pressure) applications the porous filter fabric
diaphragms eliminate venting requirements due to an inherent
ability to breathe. Many different diaphragm materials are available to fill the wide variety of needs in the industrial market.
A 3-switch Proximity® Sliquid™ model in the fuel oil application
above turns a fuel pump on at low level (12˝), turns the pump off
at high level (48˝), and activates the emergency shutoff at 51˝. In
the paint storage application shown, a 2-switch Sliquid™ model
operates a low level alarm (6˝ above the control) in an automated
paint system. The high level switch activates a high level alarm
when the paint level is 5’ above the control. This unit can be
applied for point levels up to 200 in. w.c. In the fuel oil application
shown, a dip tube provides non-contact liquid level control. A
flange-mounted contact method is illustrated in the paint application. Field adjustment is simple with high and low level springs
that are adjusted using a screwdriver. Flexibility in models offered
makes the Proximity® liquid level switch applicable for many
requirements that vary from system to system.
Chemical waste and
petroleum recycling are
applications for the
Proximity® S-D™ model,
pressure sensitive magnetic diaphragm liquid
level switches.
F High & Intermediate
Level Switches
Level
Switch
Electrically
Operated
Valve
Dip Tube
Assembly
Pressurized
Tank
Mercoid 215
Level Control
®
To
High-Low
Temperature
Alarm
Liquid
Level
The magnetic coupling provides
complete protection against
environmental damage to the
precision switch(es) in the
housing. Protection is further
enhanced in the convenient top-mounted dip tube application
depicted, in which product does not touch the diaphragm. One or
two switches in the housing are used to indicate point level of the
liquid, or mixture, as it rises in the dip tube. Rising level causes
static pressure in the dip tube to increase, depressing the
diaphragm and causing repelling magnets on the diaphragm and
switch arm(s) to actuate the switch(es) in the sealed housing.
Falling level causes decreased static pressure in the dip tube and
decreased repelling magnetic force(s). This allows spring force
to overcome the magnetic force and return both the diaphragm
and switch arm(s) to original positions. The S-D™ model is
applicable for point levels up to 48 in. w.c. Thumbscrews in the
housing allow simple adjustment of set points in the field. Both
high and low levels can be monitored with the Proximity® S-D™
model. A variety of diaphragm materials make this a flexible
product applicable in many industries.
Mercoid
DA Series
Temp.
Control
Bulb
Pressure
Well
Mercoid® level and temperature controls find wide
application in high pressure and temperature
processes.
In the example above, a pressurized holding tank in the process
system is replenished with the process media by a supply line
and electrically operated valve. The valve is controlled by a
Mercoid® 215 level control which can operate at system pressure to 300 psi at 500°F and features an adjustable level change
from 1-1/2˝ to 24˝. The temperature of the media in the holding
tank is monitored by a Mercoid® DA Series bulb and capillary
temperature control which has independent, externally
adjustable high and low setpoints. The temperature control can
actuate an alarm should the media temperature exceed the
desired limits. A well in the side of the tank protects the bulb
from the system pressure as well as allowing removal of the
bulb and control without disrupting the process.
42
pg 43
12/11/03
9:03 AM
Page 1
level
Safety Gate
Supply
Washer
Grain
hopper level
controlled
by Series PLS
Paddle
Level
Switch.
Series PLS
Paddle
Level Switch
Sliding
Doors
Series PLS
Paddle
Level Switch
Control Section
Differential pressure switch controls washer water
level.
Discharge
Pump
Motor
Control
From
Drains
CO2 to
Beverage Dispenser
Filling Box
Fill Pipe
LO
Relief
Valve
Insulating
Housing
Pump
Pressure
Tank
Mercoid® displacer
type level control is
ideal for controlling
industrial sump pumps.
HI
Capsuhelic®
Gage
Level
Sensing
Lines
Fast-food restaurant liquid CO2 tank uses
gage as level indicator.
Many fast-food restaurants utilize liquid carbon dioxide as the
source for pressurized CO2 gas for dispensing soft drinks.
Liquid CO2 requires less storage space and avoids moving
heavy compressed gas tanks in and out of the building. The
storage tank also requires less frequent servicing which can be
done from outside the building without interrupting operations.
A Capsuhelic® differential pressure gage with its 500 psi rated
operating pressure can safely handle the vapor pressure in the
tank and indicate the level of the tank contents by monitoring
the difference in pressure between the top and bottom of the
insulated tank. The gage can be calibrated in empty-full increments, inches or gallons as desired. The high pressure (tank
bottom) sensing line is run along the warm surface of the outer
insulating housing to insure the liquid CO2 is vaporized in the
sensing line, keeping the cryogenic liquid from reaching the
gage. Not all the piping and valving is illustrated in this simplified diagram and the system does include an over-pressure
relief valve for safety reasons.
Industrial sumps and other underground tanks are ideal applications for top-mounted Mercoid® displacer type level controls.
Easily installed, these controls use porcelain displacers that do
not float on the surface of liquids, but are suspended on a coil
spring and cable. As the liquid in the tank reaches the level of
the upper displacers, their weight decreases by an amount
equal to the liquid displaced, allowing the spring to move the
cable upward, actuating the switch and the pump is turned on.
As the liquid level falls below the upper displacers they move
only a small amount, staying within the switch deadband until
the liquid level falls to the center of the bottom displacer. At this
point the switch is deactivated stopping the pump. The pump
will remain deactivated until the water level rises to the upper
displacers, repeating the cycle. The displacers are not affected
by turbulence, pressure or chemicals and are excellent for tanks
with viscous or dirty liquids. The level differential is easily
adjusted by repositioning of the displacers on the 316SS cable.
43
liquid/control
This large commercial automatic washing machine requires
control of the wash and rinse water levels independent of the
timed flow of inlet water which can vary with pressure. A Dwyer
differential pressure switch is specified to sense the pressure
developed by the head of water required for proper washer
operation. The switch activates the appropriate valves to achieve
the exact water level required each time. Sensing lines must be
arranged to trap air on the fill cycle and drain completely with
each completed cycle of the machine, or else they must be
purged with instrument air.
The supply of grain pneumatically conveyed to this dispensing
hopper is controlled by two Proximity® Series PLS paddle level
switches. When the grain level falls to the low limit switch, the
supply is turned on until the hopper fills to the level of the high
limit switch which turns off the supply. Since grain dust is explosive, the explosion-proof Series PLS provides the required safety protection. The PLS is a paddle level switch and is not affected by the varying pressure in the hopper due to the cycling of
the pneumatic conveying system.
B-190
Level Control
Differential
Pressure
Switch
pg 44
12/11/03
9:06 AM
Page 1
level
Magnehelic® Gage
Water In
Vent
Refrigerated
Trailer
Steam In
LO
HI
123
Liquid Nitrogen Tank
123
Differential pressure gage measures level of liquid
nitrogen in tank.
Water Out
Liquid nitrogen forms the basis for a simple, reliable and effective in-transit refrigeration system. When sprayed under its own
gas pressure from the tank into the cargo space, the nitrogen
changes from a liquid to a gas and absorbs heat. Depending on
the tank vapor pressure, a Magnehelic® differential pressure
gage with a medium or high pressure option or a Dwyer
Capsuhelic® gage measures the level of liquid nitrogen in the
closed tank. The high pressure tap samples hydrostatic pressure of the fluid at the tank bottom and the low pressure tap
samples the gas pressure at the top of the tank. Normally, the
small amount of liquid nitrogen entering the sensing line will be
vaporized by ambient heat, thus purging the sensing line. The
differential pressure is a function of the liquid nitrogen level. The
gage can be calibrated for a given tank size in either percent of
tank capacity or in pounds of liquid nitrogen. The Magnehelic®
gage has proved it toughness by operating reliably in this overthe-road application for periods exceeding ten years.
Mercoid® model 123 level controls provide high
and low alarm on large de-aerator tank.
control
Liquid level in the external piping equals level in the tank. When
level rises to high limit, float in upper model 123 is lifted, actuating switch to sound high level alarm. When level drops to low
limit, lower model 123 sounds low level alarm.
Control
Unit
HI
Oil Tank
Capsuhelic®
Gage
Air Supply
LO
Motor
Actuated
Valve
Flowmeter
& Regulator
Fill Pipe
Series 607
Transmitter
Reservoir
HI
Liquid
Dwyer gage indicates liquid level directly.
Drain Pipe
When used with a compatible liquid, a Dwyer
Capsuhelic® differential pressure gage serves as a simple liquid
level indicator. With the high pressure port connected to a tap at
the bottom of the tank and the low pressure port vented to the
atmosphere, the oil level can be read as a function of the head with
direct calibration in feet or inches, taking into account the specific
gravity of the liquid. If the tank is closed, as indicated by the dotted lines, the differential pressure produced by the head (and
measured by having the low pressure port connected to a tap at the
top of the tank) will yield the same results regardless of total tank
pressure. As the gage will indicate head from its location to the
level in the tank, the gage must be mounted at the same elevation
as the bottom of the tank or some datum line. A minor amount of
elevation correction can be made with the zero adjust screw. A
brass housing is available for water level applications.
Transducer maintains constant liquid level in reservoir by controlling motor-actuated fill valve.
The liquid in this reservoir is maintained at a constant level by
means of the motor actuated valve controlled by the pressure
signal from a Dwyer Series 607 differential pressure transducer. The air pressure required to purge the dip tube of liquid is
equal to the reservoir depth expressed in inches of water after
taking into account the specific gravity of the liquid. Any change
in reservoir level results in a proportional change in output current from the transducer which, when fed back through the
control circuit, adjusts the valve to either increase or decrease
the fill pipe flow to maintain the desired level.
44
pg 45
12/11/03
9:08 AM
Page 1
level/temperature
Series CLT
Series F7-MQ
High High
Alarm/System
Shutdown
High Alarm
Low Alarm
Low Low
Alarm/System
Shutdown
Series VR
Custom level
sensing devices
are built to
meet each
customer’s
specific
requirements,
providing visual
indication,
continuous
measurement,
and point level
control.
Low level float switch enables sensing in air
conditioner drip pans and other shallow level
applications.
Standard float switches require at least an inch of liquid to
attain enough buoyancy to switch. This can be a problem in
applications where low level sensing is required. The hatshaped design of Dwyer’s F7-LL provides necessary buoyancy
for switching in only 5/8˝ of water. This is essential for air conditioner drip pans, low level sumps, and drains. The F7-LL is
also ideal for low alarms, where running the process dry can
result in catastrophic failure.
Package
Material
Feed Roll
Fill Funnel
W.E. Anderson®
Series OLS
indicates level in
heavy equipment
radiator.
Series 32DZ
Control
Side Seal
Heater Bars*
Model OLS
Optical Level
Switch
Top/Bottom
Seal Bars*
Control Panel
Many types of heavy industrial equipment use a liquid cooling
system for the motor. A vibratory trench roller is a machine
that compacts sub-bases for roads, parking lots, etc., and is an
example of the type of equipment that would utilize this system.
This machine incorporates a radiator cooling system. In the
system, cooling liquid circulates through the engine preventing
it from over heating. As the engine is cooled the cooling fluid
heats up. The fluid returns to the radiator to cool down before
being circulated through again. If there is not enough cooling
fluid in the system the engine will not be cooled enough and
damage will occur. A W. E. Anderson® Series OLS optical level
switch is installed as a low level alarm. The level alarm is signaled by the OLS before the cooling fluid gets to a critical low
level, warning the operator of the problem. The OLS uses an
optical detection system superior for this application as float
controls may trip from machine vibration. Also the compact
insertion length is ideal for a small radiator.
Sealed
Packet
(example:
Bag of Chips)
* Each sealer ba r set has heaters
& a Love Thermocouple
Form, fill and seal machine control simplified with
dual zone control.
Form, fill and seal machines traditionally have used separate
controls to handle the temperature control requirement for the
side and top/bottom seal bars. The Love Controls 32DZ with
Love 5000 Series thermocouples allows for a single small format (1/32 DIN) control to handle both zones, simplifying wiring
and reducing panel costs.
The 32DZ can switch small resistive loads directly or, when used
with the Love 2981 Series solid state relays (not shown), can
switch larger loads.
45
liquid/control
To meet various tank level measuring needs, Dwyer offers custom-configured products built to customer specifications that
provide visual indication, continuous level measurement, and
multiple point level measurement. Series VR or MVR ViewRite Level Indicators are a safe way to keep the process isolated while providing true visible indication. Unlike sight glasses, which can crack or break, View-Rite Indicators contain liquids entirely within their stainless steel enclosure. For continuous level measurement needs, the Series CLT uses reed
switch technology to offer a more economical solution than
expensive ultrasonic, submersible or RT transmitters. Lastly,
the Series F7-MQ can be used in virtually any tank to indicate
high and low alarms or to control pumps and valves.
Series
F7-LL
pg 46
12/11/03
9:10 AM
Page 1
temperature
Inside: Love RTD
Dwyer 657C-1 RH Transmitter
Hea ter
AL1 AL2
SP1
Power
°F
PV
SP2
Dwy er
Con troller
Series 32DZ
Control
°C
REM
SV
%
HOLD
MAN
SERIES 2600
Air Flow
(To Chamb er)
Air Flow
(To Heater )
Environmental Chamber
Sensor
control
Environmental chamber control simplified with dial
zone control.
Dwyer controllers used within heater controllers.
Environmental chambers have traditionally used separate controls to handle the temperature and relative humidity control
tasks. The Love Controls 32DZ dual zone control with Love
5000 Series RTD and Dwyer Series 657 Humidity transmitter
controls both parameters in a single small format (1/32 DIN)
control to handle both zones, simplifying wiring and reducing
panel costs.
The 32DZ can switch small resistive loads directly or, when used
with Love 2981 Series solid state relays (not shown), can switch
larger loads.
For inductive loads (solenoids, motor starters, etc.) use the
internal relays of the 32DZ to drive external contactors such as
the Love 2481 Series.
Dwy er Con troller
In bioscience laboratories, the preferred methods of temperature control for experiments are heated water baths. There are
experiments where water cannot be used, so the next feasible
option is to send temperature controlled air to the experiment
site. In order to use temperature controlled air, an air heater is
needed. Within this product, a Dwyer temperature controller is
used for accurate and responsive temperature control. The
Dwyer controller can adapt to a different environment through
different operating modes such as SELF-TUNE® or manual PID
adjustments, or preset PID responses.
Strip Pot
Power
AL1 AL2
SP1
°F
PV
SP2
°C
REM
SV
%
MAN
HOLD
SERIES 2600
Chillers & Display Cases
Series TS
Digital
Temperature
Switches
Con trol U nit
Dwyer controllers involved in insulation removal.
Series TS Digital Temperature Switches regulate
temperature in chillers and display cases.
For most wires, removing the insulation is easy, but for magnetic and enamel wires, removing the insulation is very difficult.
One way to easily remove the insulation of the magnetic or
enamel wire is to dip them in a solution of molten fused salts.
The salts are heated to a temperature high enough to melt the
salts into a liquid, but not deteriorate them. This process uses
a Dwyer feedback temperature controller. The Dwyer controller
allows the operator to input a desired temperature and maintain
that temperature accurately. The Dwyer controller will also
retain the input temperature after the power is disconnected.
When storing food or other perishables in chillers or display
cases, temperature must be carefully regulated to ensure the
products remain fresh. If the storage area rises above the critical preservation temperature, products can have their shelf life
dramatically shortened or be spoiled altogether. A Dwyer
Series TS Digital Temperature Switch will prevent these scenarios by monitoring temperature and activating refrigeration and
defrost cycles to ensure the storage temperature stays within
safe limits.
46
pg 47
12/11/03
9:13 AM
Page 1
temperature
Fill Head
Assembly
AL
SP
°F
PV
°C
SV
Duct
Air Out
SERIES 2500
Air In
Dwy er Con troller
M 51
Con diment
Packag ing
Oper ato r Interfac e
Machine Con trol
Con trols
Mercoid® Model M-51R duct temperature switch
provides high temperature cut-off on textile drying
unit.
Dwyer controllers used in the packaging of
condiments.
Hot air from a dryer flows past the Mercoid® Model M-51 duct
temperature switch. If the temperature reaches a high set point,
the bi-metal element rotates, actuating the switch to shut down
the dryer. The unit will not re-start until the Model M-51 manual reset is actuated. The Model M-51 is mounted in a special well
to prevent fouling by textile particles.
Recommended
Bulb Location
Self-Acting
Temperature Controller
AL1 AL2
SP1
°F
Hot Water Outlet
PV
SP2
°C
REM
SV
Dwy er Con troller s
%
MAN
Steam Supply
HOLD
SERIES 2600
Vacuum
Hose
Steam
Unions
Strainer
Con trols
Condensate Outlet
Regulating process temperature using W.E.
Anderson® self-acting temperature control valve.
Epoxy Resin
Molding Machine
The self-acting temperature control valve features a self-contained valve, controller, and sealed thermal system in one compact package providing installation economy and long-term
reliability. This package eliminates the temperature controller
required with standard control valves. The dispensing application shown includes a 36R valve that opens when the temperature in the hot water tank decreases allowing the steam to heat
the water and bring the temperature up to a required set point,
at which point the valve will close. A valve that closes on temperature rise (direct acting) would be required for this application. The W.E. Anderson® Hi-Flow™ quick-opening, double
seated valve enables fast response for improved process control in this application. If your application requires valve to open
on temperature rise, then a reverse acting 36R is also offered.
Resin transfer molding.
Accurate control of temperature and epoxy resin flow is important during resin transfer molding. For the epoxy resin to have
an even and thorough flow, the resin must be at a temperature
high enough to allow it to flow, yet not burn the resin. With the
help of a Dwyer controller, the temperature of the resin is accurately controlled under different conditions through the different PID operating modes. Another Dwyer controller, with a flow
transducer, is used in this process to control the flow of the
epoxy resin. The Dwyer controller provides information on the
temperature and flow rate to the computer through an RS485
serial communication option.
47
control
Packaging of condiments require the sealing bars to be heated
to a temperature hot enough to seal the packages, but not
destroy the packaging material. The heat on the sealing bars
needs to be controlled to ensure the heat does not become
excessive. Dwyer controllers are used in this process to accurately control the heat on the sealing bars. The sensors from the
Dwyer controllers are placed on the sealing bars to ensure accurate temperature readings. Should the heat become excessive,
an alarm light on the controller notifies the operator of the
impending conditions.
pg 48
12/11/03
9:19 AM
Page 1
temperature/valves
Condensate
Return Line
Vent
Process
Water
Level
Condensate
Return Tank
Heat
Exchanger
Pump
Overpressure
Relief Valve
Control
Valve Temperature
Sensor
Feedwater
Line
Boiler
I/P
Water or Steam
Feedwater
Pump
Temperature
Controller
Hi-Flow™
Valve
Level
Control
Air Supply
W.E. Anderson® Series Hi-Flow™ valves are used for
flow control of water into industrial boilers.
control
Process temperature control using pneumatic HiFlow™ control valves.
Maintaining the proper water level in a boiler is critical to its
proper operation. Too much water and water can get into the
steam lines, while too little water and the boiler can over heat.
Both conditions can lead to damage of the boiler or heating system. Feedwater going into the boiler needs to be controlled to
maintain the proper boiler water level. The W. E. Anderson® HiFlow™ globe valve is used to control the flow of the feedwater to
maintain that proper water level. The control valve is used with
a proportioning electric actuator that is directly controlled by a
level transmitter in the boiler. As the water level drops in the
boiler the valve lets in more water and as water level increases
the valve lets in less water. Thus proper water levels are always
maintained keeping the boiler operating properly and efficiently.
Pneumatic Hi-Flow™ control valves provide excellent control
with high flow, wide rangeability and tight shutoff capabilities.
The dispensing application shown uses a Lin-E-Aire® pneumatic
actuator, operating off standard 3-15 psi control air signals, and
a Hi-Flow™ linear control valve that apportions steam or water
to a user process. The valve regulates cooling water or steam
flow depending on the process requirement resident in the temperature controller program. This package can be provided with
a Precisor® positioner and Proximity® position transmitter which
provides an excellent process control application problem solution.
Acid Solution
I/P
pH Controller
Series SAE
Butterfly Valves
pH Sensor
Pump Relief Valve Control
Valve
Process
W.E. Anderson® Series SAE Butterfly Valves are utilized on hydraulic reservoirs on injection molding
machines.
Regulating pH for food and dairy applications
using linear or rotary pneumatic control valves.
The SAE valve is used as a shut off valve on the hydraulic system on injection molding machines. Normally the valve is in the
open position during operation. When the hydraulic pump
needs servicing the valve is closed to isolate the hydraulic
reservoir to prevent loss of hydraulic fluid. The SAE valve has
connections conforming to SAE J518, which is a four screw
split flange port. An o-ring seal is utilized in the connection
design that reduces leaks associated with tapered thread and
gasket type seals. The connection allows for the reduction of
unneeded adapters and has a low profile reducing space
requirements.
Hi-Flow™ pneumatic control valve, available with bronze or 316
stainless steel body and 316 stainless steel trim, provides superior corrosion resistance and durability. A lined Plast-A-Vane®
butterfly valve with pneumatic actuator could also be used to
provide excellent corrosion resistant characteristics. Both types
of valves yield superb flow characteristics and enhanced shutoff capabilities ensuring years of trouble-free, reliable operation.
In the application shown, throttle action of the High-Flow™ linear globe valve, or the rotary movement of the Plast-A-Vane®
quarter-turn butterfly valve, is used to regulate the flow of acid
solution into a food/dairy process to accurately control the pH
of the system.
48
valves
pg 49 (PATENTS UPDATED):pg 49
3/16/11
10:14 AM
Page 1
Air
Supply
Control Panel
Position
Indicator
Actuator
Check
Valve
P
Local or
Remote
Electrical
Position
Indication
Control Valve
Continuous
Electrical (4-20mA)
Retort
Optional
Cooling Enable
Solenoid Valve
Proximity® Mark Series valve position indicator is
perfect for valve position indication on offshore oil
rigs.
Hand
Valve
Quick response Hi-Flow™ valves control water
flow in cooling process.
Dependable W.E. Anderson® Hi-Flow™ control valves with LinE-Aire® air-to-raise actuators combine to provide unsurpassed
water flow management. This retort system employs the HiFlow™ valve because of its excellent control capabilities,
which are necessary for this application. After the cooking
process, the valve is opened slowly. Once the desired temperature has been reached, the supply is shut off and any additional cooling is done by use of the hand valve.
Position
Indicator
Air Intake
Filter
Aftercooler
Water Separator
Inlet
Actuator
Air
Receiver
Control Valve
Discrete Visual
Local
Visual
Indication
Open Closed
0° 30° 45° 60°90°
Continuous Visual
Visual valve position indication with Proximity®
explosion-proof position indicators provides
convenience and enhanced safety in valve
monitoring.
Air Outlet
Trap
Compressor unloading using W.E. Anderson®
Plast-A-Vane® butterfly valve.
When receiver pressure rises to a predetermined setting, the
total closure valve closes automatically, blocking the air inlet
and preventing air from entering the compressor. After all
compressed air is evacuated from the cylinders and intercooler, the solenoid control valve on the high-pressure cylinder is
opened to atmosphere allowing that minute amount of air
remaining in the high-pressure cylinder to be exhausted. The
compressor is now operating in a vacuum with minimal losses due only to mechanical friction in bearings and on sliding
surfaces. Minimal horsepower is needed to overcome the
mechanical losses.
49
For the convenience of the control valve user, a compact,
adjustable stainless steel visual indicator is provided on all directdrive Proximity® position indicating switches and transmitters.
These industrial switches are commonly mounted on quarter-turn
pneumatic actuators and valves. A magnetic design provides maximum safety by allowing complete sealing of the switch cavity.
Over 2000 specific applications are covered with an extensive line
of mounting kits built for individual valve and actuator brands and
model numbers. As the valve and actuator is cycled, the input shaft
of the position indicator rotates, causing a stainless steel cylinder
to rotate inside a second stainless steel cylinder with windows.
When the valve is open the word “OPEN” appears in the two windows located 180° apart. The compact and durable visual indicator
displays discrete endpoints (OPEN or CLOSED) as well as scaled
degrees (0-90). LED and flow path outputs are available options.
Up to 3 conduit entrances allow utilization of this flexible indicator
as a junction box for additional convenience as well as material and
labor cost reduction to the user.
control
Proximity® Mark Series position indicator is utilized in valve
automation packages in harsh environments. The Mark Series
mounts onto the top of rotary valve actuators and connects to
the actuator shaft or attaches to the shaft of a linear valve for
indicating valve position. Standard with the Mark Series is visual position indication with “OPEN”, “CLOSED”, and degree position status. The Mark Series is available with continuous position retransmission with a 4 to 20 mA output and up to six
adjustable position indication switches for remote indication of
valve status. Remote status transmitter is used for indication of
exact valve position and switches provide discrete indication of
valve open and closed status in the control room. The Mark
Series is perfect for this application because of the 316 SS
enclosure that withstands the sea spray environment, and the
magnetic drive mechanism that completely seals the switch cavity from the environment.
60 psi
Water Supply
Water Outlet
Alarm
Light
Discrete Electrical
pg 50
12/11/03
9:22 AM
Page 1
valves/miscellaneous
Position
Indicator
Actuator
Tower Exhauster
Open Closed
Local
Visual
Indication
Discrete Visual
Fan
0° 30° 45° 60°90°
Control Valve
Proximity® Series QV indicates valve position
locally and remotely.
Plate
Heat
Exchange
Proximity Series QV position indicator is utilized in valve automation package. Quarter turn valves such as ball and butterfly valves
are often automated with pneumatic or electric actuators. The
actuator connects to the shaft of the valve and rotates it. Usually
the actuator has a shaft of its own that comes out of the top and
rotates as the actuator rotates the valve. The QV mounts onto the
top of the actuator and connects to this actuator shaft for indicating valve position. When the valve is open or closed, the corresponding word “OPEN” or “CLOSED” appears in four windows 90°
apart. The visual indicator also includes degree position indication
of 0 to 90°. The QV is compact yet the visual indictor is large and
easy to view from a distance. Adjustable position indication
switches are available to remotely indicate if the valve is fully
opened or closed. The QV assures proper operation of the valve
and indicates problems so they can quickly be addressed.
process
®
Series BDL
Button Data
Logger
Chiller
Cooling Tower
Continuous Visual
Water-side Economizer System includes Plast-AVane® 3-way butterfly valve for accurate control
of flow.
To ensure efficient utilization of cold water in HVAC systems,
W.E. Anderson® Plast-A-Vane® 3-way butterfly valves are called
upon to modulate flow. This common “water-side economizer”
allows water from the plate heat exchanger to be diverted
directly to the cooling tower if the temperature is cool enough,
instead of coming directly from the condenser on the chiller.
10¢
Series 450
Carbon Monoxide
Monitor
Quickly determine a building’s carbon monoxide
levels with Carbon Monoxide Monitor
Button Datalogger monitors food and beverage
temperature in refrigerated transport vehicles.
The Dwyer Series 450 Carbon Monoxide Monitor is the ideal
handheld instrument used by Building Inspectors and Building
Maintenance Supervisors for inspecting indoor carbon monoxide (CO) levels. To determine if a building's indoor air meets
safe allowable levels set by ASHRAE, an inspector can easily
walk through a building with the 450 to see if the building meets
code. With the 450's peak CO recording feature, the user can
quickly determine if any part of the facility surpassed the safe
allowable level. An audible and visual light respond when user
programmed limits are exceeded. The 450 CO Monitor is also
used by workers in tunnels, mines and sewers.
When transporting temperature-sensitive products such as
meat, produce, beer and wine over long distances, it is necessary to verify that the storage compartment has not exceeded
the critical preservation temperature at any time. Dwyer BDL
Button Dataloggers offer a low cost way to measure and record
storage temperatures throughout transport. By placing several
“buttons” throughout the storage compartment and setting an
appropriate measurement interval, transportation services can
retrieve data at the completion of delivery to assure their customers of adequate preservation temperatures.
50
pg 51
12/11/03
9:23 AM
Page 1
miscellaneous
CH4
Air
Preheater
Boiler
Combustion gas
Series 485
Digital
Hygrometer
Feedwater
Steam
Combustion analyzer maximize boiler efficiency
while monitoring harmful products of combustion.
The Dwyer 485 Handheld Digital Hygrometer is a simple,
portable device for quickly measuring humidity and temperature levels in ambient air. The dew point and wet-bulb temperature readings are derived from relative humidity and
temperature measurements. The 485 is often used in agricultural applications where proper humidity and temperature
levels are critical in plant or animal well being.
There are several critical factors in attaining efficient combustion for boilers and other combustors. Monitoring the temperature of combustion and minimizing the amount of excess air in
the system are undoubtedly essential steps. A Dwyer 1207-NOX
Flue Gas Analyzer can break down the products of combustion,
giving an accurate volumetric composition of harmful NOX compounds, O2, CO2, and CO. Additionally, the 1207-NOX will monitor differential temperature, excess air and poison index.
Results can be easily viewed on screen or uploaded to a PC via
the user-friendly software.
Series DL8
Transmitter
Pressure
Transmitter
Temperature
Transmitter
Flow
Transmitter
Model LC21
Smart Loop
Calibrator
Air Velocity
Transmitter
Level
Transmitter
Dataloggers simplify performance assessment for
multiple transmitters and other measurement
devices.
Perform field calibration of transmitters and control systems.
For testing transmitters and other process loop components,
Dwyer’s LC21 Smart Loop Calibrator is the ideal instrument.
The LC21 can be used to simulate any two of the three basic
components of an analog process loop, the transmitter, indicator, or power supply. To perform calibration tests on an
indicator, panel meter, or PLC, the LC21 will simulate a transmitter by sourcing an analog output signal while providing the
loop power supply. To perform calibration tests on a transmitter, the Smart Loop Calibrator will simulate the indicator while
providing the power supply. The end result is a compact,
portable, easy-to-use calibration tool for analog systems.
Data acquisition is an essential tool for process monitoring and
system evaluation. It is also an integral factor in troubleshooting and malfunction testing. Dwyer’s DL8 Process Datalogger
enables users to acquire data from up to seven transmitters or
other instruments by accepting industry standard analog inputs.
With easy-to-use software, plots of the instruments’ performance can be conveniently uploaded and viewed graphically or
numerically on a PC or laptop. Additionally, the DL8 can monitor data in real time for instant results or acquire data over a
user-defined interval for long-term monitoring.
51
analyze/measure/control
Quickly measure humidity and temperature levels in ambient air.
pg 52
12/11/03
9:27 AM
Page 1
reference
reference
SPECIFIC GRAVITY OF LIQUID
Liquid
Specific Gravity
Acetone
Alcohol, ethyl
Alcohol, methyl
Ammonia, saturated
Benzene
Brine (10% Na Cl)
Carbolic acid
Carbon disulfide
Carbon tetrachloride
Chloroform
Ether
Fuel Oils
1
2
3
5A
5B
6
Gas oils
Gasolines
a
b
c
Glycerine
Heptane-n
Hexane
Kerosene
Mercury
Methyl acetate
Methyl iodide
Milk
Naptha, petroleum ether
Naptha, wood
Oils
Castor
Coconut
Cotton seed
Creosote
Linseed, boiled
Olive
Palm
Peanut
Sesame Seed
Soy Bean
Pentane
Propylene glycol
SAE 30 Lube Oil
Sea Water
Sodium chloride
5%
25%
0.792
0.791
0.810
0.655
0.9
1.08
0.950 to 0.965
1.293
1.595
1.489
0.736
Sodium hydroxide (caustic soda)
20%
30%
40%
Turpentine (spirits)
Water
0.82 to 0.95
0.82 to 0.95
0.82 to 0.95
0.82 to 0.95
0.82 to 0.95
0.82 to 0.95
0.89
0.74
0.72
0.68
1.260
0.688
0.664
0.820
13.600
0.93
2.28
1.028 to 1.035
0.665
0.848 to 0.810
0.969
0.925
0.926
1.040 to 1.200
0.924
0.918
0.924
0.92
0.923
0.924 to .928
.623
1.038
0.9
1.025
AREA OF CIRCLES IN FT2
ALTITUDE PRESSURE TABLE
Mercury at 0°C (32°F)
Diam. AREA Diam.
in
in
Square
Inches Feet Inches
In
Inches
Millimeters
Altitude
in feet of Mercury of Mercury
-1,000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
31.02
29.921
28.86
27.82
26.81
25.84
24.89
23.98
23.09
22.22
21.38
20.58
16.88
13.75
11.10
8.88
7.04
5.54
4.36
3.436
1
11⁄2
2
21⁄2
3
31⁄2
4
41⁄2
5
51⁄2
6
61⁄2
7
71⁄2
8
81⁄2
9
91⁄2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
787.9
760.0
732.9
706.6
681.1
656.3
632.3
609.0
586.4
564.4
543.2
522.6
428.8
349.1
281.9
225.6
178.7
140.7
110.8
87.30
SPECIFIC GRAVITIES OF GASES
(BASED ON 68°F AND 14.7 LBS. ABS.)
ACETYLENE
AIR
AMMONIA
ARGON
BUTANE-N
BUTANE-ISO
CARBON DIOXIDE
CARBON MONOXIDE
CHLORINE
ETHANE
HELIUM
HYDROGEN
METHANE
NATURAL GAS
C2H2
.897
1.000
.587
1.378
2.390
1.990
1.517
.966
2.452
1.035
.138
.070
.553
.665
. . . . . . .
NH3
A
C4H40
(CH)3)2CH CH3
CO2
CO
CL2
C2H6
He
H2
CH4
. . . . . .
NO
N2
N20
02
C3H8
SO2
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
56
58
60
62
64
66
68
70
72
74
76
78
80
4.909
5.241
5.585
5.940
6.305
6.611
7.069
7.467
7.876
8.296
8.727
9.168
9.621
10.08
10.56
11.04
11.54
12.05
12.57
13.10
13.64
14.19
14.75
15.32
15.90
17.10
18.35
19.63
20.97
22.34
23.76
25.22
26.73
28.27
29.87
31.50
33.18
34.91
VOLUME EQUIVALENTS
1 CU. FT. = 1728 Cu. In.
7.481 Gal. (U.S.)
28.317 Liters
28.317 Cu. Cm.
1 GAL. (U.S.) = 231 Cu. In.
.1337 Cu. Ft.
3.785 Liters
3785 Cu. Cm.
1 LITER = .0353 Cu. Ft.
.2642 Gal. (U.S.)
1000 Cu. Cm.
(Approx. Avg.)
NITRIC OXIDE
NITROGEN
NITROUS OXIDE
OXYGEN
PROPANE
SULPHUR DIOXIDE
.0054
.0123
.0218
.0341
.0491
.0668
.0873
.1105
.1364
.1650
.1964
.2305
.2673
.3068
.3491
.3940
.4418
.4923
.5454
.6600
.7854
.9218
1.069
1.227
1.396
1.576
1.767
1.969
2.182
2.405
2.640
2.885
3.142
3.409
3.687
3.976
4.276
4.587
AREA
Square
Feet
1.035
.966
1.518
1.103
1.550
2.209
FLOW EQUIVALENTS
1 Cu. Ft./Hr.
1.037
1.196
1.19
.0166
.4719
28.316
471.947
28317
.1247
7.481
1.22
1.33
1.43
0.870
1.000
60
.035
2.1189
1000
60,002
.264
15.851
1 Cu. Ft./Min.
60 Cu. Ft./Hr.
Cu. Ft./Min.
28.316 LPM
LPM
1699 LPH
LPH
28317 CC/Min.
CC/Min.
1,699,011 CC/Hr.
CC/Hr.
7.481 Gal/Min.
Gal/Min.
448.831 Gal/Hr.
Gal/Hr.
1 LPM
LPH
Cu. Ft./Min.
Cu. Ft./Hr.
CC/Min.
CC/Hr.
Gal/Min.
Gal/Hr.
52
1 LPH
.0166
.00059
.035
16.667
1000
.004
.264
1 CC/Min.
60
.000035
.0021
.001
.06
.00026
.0159
CC/Hr.
Cu. Ft./Min.
Cu. Ft./Hr.
LPM
LPH
Gal/Min.
Gal/Hr.
1 Gal/Min.
LPM
60 Gal/Hr.
Cu. Ft./Min.
.1337 Cu. Ft./Min.
Cu. Ft./Hr.
8.021 Cu. Ft./Hr.
CC/Min.
3.785 LPM
CC/Hr.
227.118 LPH
Gal/Min.
3,785.412 CC/Min.
Gal/Hr.
227,125 CC/Hr.
1 CC/Hr.
.0167
.0000005
.00003
.000017
.001
.000004
.00026
CC/Min.
Cu. Ft./Min.
Cu. Ft./Hr.
LPM
LPH
Gal/Min.
Gal/Hr.
1 Gal/Hr.
.0167
.002
.1337
.063
3.785
63.069
3785
Gal/Min.
Cu. Ft./Min.
Cu. Ft./Hr.
LPM
LPH
CC/Min.
CC/Hr.
dom.ifc/ibc
12/11/03
8:19 AM
Page 1
Pressure Conversion Chart
Founded in 1931, Dwyer Instruments, Inc. produces a broad range of competitively priced
precision instruments for measuring, transmitting and controlling pressure, temperature
level, flow and related applications.
Many of these instruments are widely know by their individual brand names, such as
Magnehelic® and Spirahelic® pressure gages, Photohelic® switch/gages, Rate-Master® and
Visi-Float® flowmeters and Hi-Flow® valves. Divisions include well-known brand names such
as Mercoid, W.E. Anderson, Proximity Controls and Love Controls.
Headquartered in Michigan City, Indiana, the company has four more Indiana manufacturing
facilities, as well as manufacturing facilities in Anaheim, California; Fergus Falls, Minnesota;
Kansas City, Missouri; and Naguabo, Puerto Rico.
In addition to making and selling quality precision instruments, Dwyer is committed to a standard of customer service – including competitive prices and knowledgeable, courteous technical support – that generates and sustains long-term relationships.
Customer Service
Fast, friendly customer service professionals are available to
process and provide assistance with your order – whether it
is by phone, fax, e-mail or through our website.
Technical Support
Have an application question? Our technical support
professionals are trained to provide you with the
answers you need.
Prompt Shipments
After you place your order, Dwyer’s dedicated
shipping staff packs and ships your order promptly
and completely –within 24 hours on most in-stock
items.
Website
Dwyer Instrument’s website delivers the convenience
you want. Go to www.dwyer-inst.com for the most
complete ordering and product support information at
your fingertips – anytime, day or night. Installation and
operating manuals are available on products that are
easily downloadable to your computer or printer.
Total customer service the way you need it.
Dwyer Instruments, Inc.
accepts Visa® and
Mastercard®.
Address:
Dwyer Instruments, Inc.
102 Indiana Highway 212
P.O. Box 373
Michigan City, IN 46361 U.S.A.
e-mail:
General: [email protected]
Literature: [email protected]
Technical: [email protected]
Quotes: [email protected]
website:
http://www.dwyer-inst.com
http://www.love-controls.com
http://dwyer-inst.com/retail
http://proximitycontrols.com
Telephone:
(800) 872-9141
(219) 879-8000
Fax:
(219) 872-9057
in/H2O
P.S.I.
in/Hg
mm/H2O mm/Hg
.1
.2
.4
.6
.8
1.0
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
.0036
.0072
.0144
.0216
.0289
.0361
.0722
.1083
.1444
.1804
.2165
.2526
.2887
.3248
.3609
.3970
.4331
.4692
.5053
.5414
.5774
.6136
.6496
.6857
.7218
.7579
.7940
.8301
.8662
.9023
.9384
.9745
1.010
1.047
1.083
1.119
1.155
1.191
1.227
1.263
1.299
1.335
1.371
1.408
1.444
1.480
1.516
1.552
1.588
1.624
1.660
1.696
1.732
1.768
1.804
1.841
1.877
1.913
1.949
1.985
2.021
2.057
2.093
2.129
2.165
2.202
2.238
2.274
2.310
2.346
2.382
2.418
2.454
2.490
2.526
2.562
2.598
2.635
2.671
2.707
2.743
2.779
2.815
2.851
2.887
2.923
2.959
2.996
3.032
3.068
3.104
3.140
3.176
3.212
3.248
3.284
3.320
3.356
3.392
3.429
3.456
3.501
3.537
3.573
3.609
.0073
.0146
.0293
.0440
.0588
.0735
.1470
.2205
.2940
.3673
.4408
.5143
.5878
.6613
.7348
.8083
.8818
.9553
1.029
1.102
1.176
1.249
1.322
1.396
1.470
1.543
1.616
1.690
1.764
1.837
1.910
1.984
2.056
2.132
2.205
2.278
2.352
2.425
2.498
2.571
2.645
2.718
2.791
2.876
2.940
3.013
3.086
3.160
3.233
3.306
3.378
3.453
3.526
3.600
3.673
3.748
3.822
3.895
3.968
4.041
4.115
4.188
4.261
4.335
4.408
4.483
4.556
4.630
4.703
4.776
4.850
4.923
4.996
5.070
5.143
5.216
5.290
5.365
5.438
5.511
5.585
5.658
5.731
5.805
5.878
5.951
6.024
6.100
6.173
6.246
6.320
6.393
6.466
6.450
6.613
6.686
6.760
6.833
6.906
6.981
7.055
7.128
7.201
7.275
7.348
2.534
5.067
10.13
15.20
20.34
25.41
50.81
76.22
101.62
127.0
152.4
177.8
203.2
228.6
254.0
279.4
304.8
330.2
355.6
381.0
406.4
431.8
457.2
482.6
508.0
533.4
558.8
584.2
609.6
635.0
660.4
685.8
710.8
736.8
762.2
787.5
812.8
836.2
863.5
888.9
914.2
939.5
964.9
990.9
1016
1042
1067
1092
1118
1143
1168
1194
1219
1244
1270
1296
1321
1346
1372
1397
1422
1448
1473
1498
1524
1550
1575
1600
1626
1651
1676
1702
1727
1752
1778
1803
1828
1854
1880
1905
1930
1956
1981
2006
2032
2057
2082
2108
2134
2159
2184
2210
2265
2260
2286
2311
2336
2362
2387
2413
2438
2464
2489
2514
2540
.1863
.3726
.7452
1.118
1.496
1.868
3.736
5.604
7.472
9.335
11.203
13.072
14.940
16.808
18.676
20.544
22.412
24.280
26.148
28.016
29.879
31.752
33.616
35.484
37.352
39.22
41.09
42.96
44.82
46.69
48.56
50.43
52.26
54.18
56.04
57.91
59.77
61.63
63.49
65.36
67.22
69.08
70.95
72.86
74.72
76.59
78.45
80.31
82.18
84.04
85.90
87.76
89.63
91.49
93.35
95.27
97.13
98.99
100.8
102.7
104.6
106.4
108.3
110.2
112.0
113.9
115.8
117.7
119.5
121.4
123.3
125.1
127.0
128.8
130.7
132.6
134.4
136.4
138.2
140.1
141.9
143.8
145.7
147.5
149.4
151.2
153.1
155.0
156.9
158.8
160.6
162.5
164.4
166.2
168.1
169.9
171.8
173.7
175.5
177.4
179.3
181.2
183.0
184.9
186.8
kg/cm2
bar
mbar
Pa
kPa
P.S.I.
in/H2O
in/Hg
mm/H2O mm/Hg
kg/cm2
.0002
.0005
.0010
.0015
.0020
.0025
.0051
.0076
.0102
.0127
.0152
.0178
.0203
.0228
.0254
.0279
.0304
.0330
.0355
.0381
.0406
.0431
.0457
.0482
.0507
.0533
.0558
.0584
.0609
.0634
.0660
.0685
.0710
.0736
.0761
.0787
.0812
.0837
.0862
.0888
.0913
.0938
.0964
.0990
.1015
.1040
.1066
.1091
.1116
.1142
.1167
.1192
.1218
.1243
.1268
.1294
.1320
.1345
.1370
.1395
.1421
.1146
.1471
.1497
.1522
.1548
.1573
.1599
.1624
.1649
.1674
.1700
.1725
.1750
.1776
.1801
.1826
.1852
.1878
.1903
.1928
.1954
.1979
.2004
.2030
.2055
.2080
.2106
.2131
.2157
.2182
.2207
.2233
.2258
.2283
.2309
.2334
.2359
.2384
.2410
.2436
.2461
.2486
.2512
.2537
.0002
.0005
.0010
.0015
.0020
.0025
.0050
.0075
.0099
.0124
.0149
.0174
.0199
.0224
.0249
.0274
.0299
.0324
.0348
.0373
.0398
.0423
.0448
.0473
.0498
.0523
.0547
.0572
.0597
.0622
.0647
.0672
.0696
.0722
.0747
.0772
.0796
.0821
.0846
.0871
.0896
.0920
.0945
.0971
.0996
.1020
.1045
.1070
.1095
.1120
.1144
.1169
.1194
.1219
.1244
.1269
.1294
.1319
.1344
.1369
.1393
.1418
.1443
.1468
.1493
.1518
.1543
.1568
.1593
.1618
.1642
.1667
.1692
.1717
.1742
.1766
.1791
.1817
.1842
.1866
.1891
.1916
.1941
.1966
.1991
.2015
.2040
.2066
.2091
.2115
.2140
.2165
.2190
.2215
.2239
.2264
.2289
.2314
.2339
.2364
.2389
.2414
.2439
.2464
.2488
.2482
.4964
.9928
1.489
1.992
2.489
4.978
7.467
9.956
12.44
14.93
17.42
19.90
22.39
24.88
27.37
29.86
32.35
34.84
37.33
39.81
42.31
44.79
47.28
49.77
52.26
54.74
57.23
59.72
62.21
64.70
67.19
69.64
72.19
74.67
77.15
79.63
82.12
84.60
87.08
89.56
92.04
94.53
97.08
99.56
102.0
104.5
107.0
109.5
112.0
114.5
116.9
119.4
121.9
124.4
126.9
129.4
131.9
134.4
136.9
139.3
141.8
144.3
146.8
149.3
151.8
154.3
156.8
159.3
161.8
164.2
166.7
169.2
171.7
174.2
176.6
179.1
181.7
184.2
186.6
189.1
191.6
194.1
196.6
199.1
201.5
204.0
206.6
209.1
211.5
214.0
216.5
219.0
221.5
223.9
226.4
228.9
231.4
233.9
236.4
238.9
241.4
243.9
246.4
248.8
24.82
49.64
99.28
148.9
199.2
248.9
497.8
746.7
995.6
1244
1493
1742
1990
2239
2488
2737
2986
3235
3484
3733
3981
4231
4479
4728
4977
5226
5474
5723
5972
6221
6470
6719
6964
7219
7467
7715
7963
8212
8460
8708
8956
9204
9453
9708
9956
10204
10452
10701
10949
11197
11445
11694
11942
12190
12438
12693
12941
13190
13438
13686
13934
14182
14431
14679
14927
15182
15430
15679
15927
16175
16423
16672
16920
17168
17416
17664
17912
18168
18416
18664
18912
19160
19409
19657
19905
20153
20402
20657
20905
21153
21401
21650
21898
22146
22394
22642
22890
23139
23387
23642
23890
24138
24387
24635
24883
.0248
.0496
.0993
.1489
.1992
.2489
.4978
.7476
.9956
1.244
1.493
1.742
1.990
2.239
2.488
2.737
2.986
3.235
3.484
3.733
3.981
4.231
4.479
4.728
4.977
5.226
5.474
5.723
5.972
6.221
6.470
6.719
6.964
7.219
7.467
7.715
7.963
8.212
8.460
8.708
8.956
9.204
9.453
9.708
9.956
10.20
10.45
10.70
10.95
11.20
11.44
11.69
11.94
12.19
12.44
12.69
12.94
13.19
13.44
13.69
13.93
14.18
14.43
14.68
14.93
15.18
15.43
15.68
15.93
16.18
16.42
16.67
16.92
17.17
17.42
17.66
17.91
18.17
18.42
18.66
18.91
19.16
19.41
19.66
19.90
20.15
20.40
20.66
20.90
21.15
21.40
21.65
21.90
22.15
22.39
22.64
22.89
23.14
23.39
23.64
23.89
24.14
24.39
24.64
24.88
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
6.0
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
7.0
7.1
7.2
7.3
7.4
7.5
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0
9.2
9.4
9.6
9.8
10.0
11.0
12.0
13.0
14.0
14.7
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
27.71
30.45
33.22
35.98
38.75
41.52
44.29
47.06
49.82
52.59
55.36
58.13
60.90
63.67
66.43
69.20
71.97
74.74
77.51
80.27
83.04
85.81
88.58
91.35
94.11
96.88
99.65
102.4
105.2
108.0
110.7
113.5
116.3
119.0
121.8
124.6
127.3
130.1
132.9
135.6
138.4
141.2
143.9
146.7
149.5
152.2
155.0
157.8
160.5
163.3
166.1
168.8
171.6
174.4
177.2
179.9
182.7
185.5
188.2
191.0
193.8
196.5
199.3
202.1
204.8
207.6
210.4
215.9
221.4
227.0
232.5
238.0
243.6
249.1
254.7
260.2
265.7
271.3
276.8
304.5
332.2
359.8
387.5
406.9
415.2
442.9
470.6
498.2
525.9
553.6
581.3
609.0
636.7
664.3
692.0
2.036
2.240
2.443
2.647
2.850
3.054
3.258
3.461
3.665
3.686
4.072
4.276
4.479
4.683
4.886
5.090
5.294
5.497
5.701
5.904
6.108
6.312
6.515
6.719
6.922
7.126
7.330
7.535
7.737
7.940
8.144
8.348
8.551
8.775
8.958
9.162
9.366
9.569
9.773
9.976
10.18
10.38
10.59
10.79
10.99
11.20
11.40
11.60
11.81
12.01
12.22
12.42
12.62
12.83
13.03
13.23
13.44
13.64
13.84
14.05
14.25
14.46
14.66
14.86
15.07
15.27
15.47
15.88
16.29
16.70
17.10
17.51
17.92
18.32
18.73
19.14
19.54
19.95
20.36
22.40
24.43
26.47
28.50
29.93
30.54
32.58
34.61
36.65
36.68
40.72
42.76
44.79
46.83
48.86
50.90
703.1
773.4
843.7
914.0
984.3
1055
1125
1195
1266
1336
1406
1476
1547
1617
1687
1758
1828
1898
1969
2039
2109
2180
2250
2320
2390
2461
2531
2601
2672
2742
2812
2883
2953
3023
3094
2164
3234
3304
3375
3445
3515
3586
3656
3726
3797
3876
3973
4008
4078
4148
4218
4289
4359
4429
4500
4570
4640
4711
4781
4851
4922
4992
5062
5132
5203
5273
5343
5484
5625
5765
5906
6047
6187
6328
6468
6609
6750
6890
7031
7734
8437
9140
9843
10340
10550
11250
11950
12660
13360
14060
14770
15470
16170
16870
17580
.0703
.0773
.0844
.0914
.0984
.1055
.1125
.1195
.1266
.1336
.1406
.1476
.1547
.1617
.1687
.1758
.1828
.1898
.1968
.2039
.2109
.2180
.2250
.2320
.2390
.2461
.2531
.2601
.2672
.2742
.2812
.2883
.2953
.3023
.3094
.3164
.3234
.3304
.3375
.3445
.3515
.3586
.3656
.3726
.3797
.3867
.3937
.4007
.4078
.4148
.4218
.4289
.4359
.4429
.4500
.4570
.4640
.4710
.4781
.4851
.4921
.4992
.5062
.5132
.5203
.5273
.5343
.5484
.5625
.5765
.5906
.6046
.6187
.6328
.6468
.6609
.6749
.6890
.7031
.7734
.8437
.9140
.9843
1.033
1.055
1.125
1.195
1.265
1.336
1.406
1.476
1.547
1.617
1.687
1.758
CONVERSION
FACTORS
NOTE:
CONVERSION FACTORS
ROUNDED
51.75
56.89
62.06
67.23
72.40
77.57
82.74
87.92
93.09
98.26
103.4
108.6
113.8
118.9
124.1
129.3
134.5
139.6
144.8
150.0
155.1
160.3
165.5
170.7
175.8
181.0
186.2
191.3
196.5
201.7
206.9
212.0
217.2
222.4
227.5
232.7
237.9
243.1
248.2
253.4
258.6
263.7
268.9
274.1
279.3
284.4
289.6
294.8
299.9
305.1
310.3
315.5
320.6
325.8
331.0
336.1
341.3
346.5
351.7
356.8
362.0
367.2
372.3
377.5
382.7
387.9
393.0
403.4
413.7
424.1
434.4
444.7
455.1
465.4
475.8
486.1
496.5
506.8
517.1
568.9
620.6
672.3
724.0
760.2
775.7
827.4
879.1
930.9
982.6
1034
1086
1138
1189
1241
1293
P.S.I.
P.S.I.
P.S.I.
P.S.I.
P.S.I.
x
x
x
x
x
27.71
2.036
703.1
51.75
.0703
=
=
=
=
=
bar
mbar
.0689
.0758
.0827
.0896
.0965
.1034
.1103
.1172
.1241
.1310
.1379
.1448
.1517
.1586
.1655
.1724
.1793
.1862
.1930
.1999
.2068
.2137
.2206
.2275
.2344
.2413
.2482
.2551
.2620
.2689
.2758
.2827
.2896
.2965
.3034
.3103
.3172
.3240
.3310
.3378
.3447
.3516
.3585
.3654
.3723
.3792
.3861
.3930
.3999
.4068
.4137
.4206
.4275
.4344
.4413
.4482
.4550
.4619
.4688
.4757
.4826
.4895
.4964
.5033
.5102
.5171
.5240
.5378
.5516
.5654
.5792
.5929
.6067
.6205
.6343
.6481
.6619
.6757
.6895
.7584
.8274
.8963
.9652
1.014
1.034
1.103
1.172
1.241
1.310
1.379
1.448
1.517
1.586
1.655
1.724
68.95
75.84
82.74
89.63
96.52
103.4
110.3
117.2
124.1
131.0
137.9
144.8
151.7
158.6
165.5
172.4
179.3
186.2
193.0
199.9
206.8
213.7
220.6
227.5
234.4
241.3
248.2
255.1
262.0
268.9
275.8
282.7
289.6
296.5
303.4
310.3
317.2
324.0
331.0
337.8
344.7
351.6
358.5
365.4
372.3
379.2
386.1
393.0
399.9
406.8
413.7
420.6
427.5
434.4
441.3
448.2
455.0
461.9
468.8
475.7
482.6
489.5
496.4
503.3
510.2
517.1
524.0
537.8
551.6
565.4
579.2
592.9
606.7
620.5
634.3
648.1
661.9
675.7
689.5
758.4
827.4
896.3
965.2
1014
1034
1103
1172
1241
1310
1379
1448
1517
1586
1655
1724
in. H2O
in. Hg
mm/H2O
mm/Hg
kg/cm2
P.S.I.
P.S.I.
P.S.I.
P.S.I.
Pa
6895
7584
8274
8963
9652
10340
11030
11720
12410
13100
13790
14480
15170
15860
16550
17240
17930
18620
19300
19990
20680
21370
22060
22750
23440
24130
24820
25510
26200
26890
27580
28270
28960
29650
30338
31030
31720
32400
33100
33780
34470
35160
35850
36540
37230
37920
38610
39300
39990
40680
41370
42060
42750
43440
44130
44820
45500
46190
46880
47570
48260
48950
49640
50330
51020
51710
52400
53780
55160
56540
57920
59290
60670
62050
63430
64810
66190
67570
68950
75840
82740
98630
96520
101400
103400
110300
117200
124100
131000
137900
144800
151700
158600
165500
172400
x
x
x
x
kPa
6.895
7.584
8.274
8.963
9.652
10.34
11.03
11.72
12.41
13.10
13.79
14.48
15.17
15.86
16.55
17.24
17.93
18.62
19.30
19.99
20.68
21.37
22.06
22.75
23.44
24.13
24.82
25.51
26.20
26.89
27.58
28.27
28.96
29.65
30.34
31.03
31.72
32.40
33.10
33.78
34.47
35.16
35.85
36.54
37.23
37.92
38.61
39.30
39.99
40.68
41.37
42.06
42.75
43.44
44.13
44.82
45.50
46.19
46.88
47.57
48.26
48.95
49.64
50.33
51.02
51.71
52.40
53.78
55.16
56.54
57.92
59.29
60.67
62.05
63.43
64.81
66.19
67.57
68.95
75.84
82.74
89.63
96.52
101.4
103.4
110.3
117.2
124.1
131.0
137.9
144.8
151.7
158.6
165.5
172.4
.0689 = bar
68.95 = mbar
6895 = Pa
6.895 = kPa
obc/ofc
12/11/03
8:10 AM
Page 1
DWYER INSTRUMENTS, INC.
P.O. Box 373
Michigan City, IN 46361-9986
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