DP Pilot Operated Pressure Reducing Valves

DP Pilot Operated Pressure Reducing Valves
1000132/3
IM-S10-25
CH Issue 3
DP
Pilot Operated Pressure Reducing Valves
Fitting Instructions
Main Valve Assembly,
Main Valve Return Spring,
Pushrod, Lock-nut and Main Diaphragm Plate Set.
Warning
For full Installation and Maintenance Instructions, inclusive of safety information, see the
relevant documents supplied with the product and listed below.
Valve type
37D and 37DE
DP143
DP17, DP17E and DP17R
DP17T and DP17TE
DP27
DP27T
IM reference no.
IM - P102 - 04
IM - P00 6 - 07
IM - P100 - 05
IM - P101 - 04
IM - P470 - 03
IM - P470 - 09
Note: Installation and Maintenance Instructions are available separately from Spirax Sarco.
Fitting instructions
2
For the DP17, DP17E and DP17G:
Isolate the reducing valve and zero the
pressure.
1
1. Release the lock-nut.
2. Turn the adjustment screw anticlockwise.
3
4
3. Slide out the 'C' washer.
4. Remove the cover.
5. Remove the spring and top plate.
5
Printed
in theCH
UKIssue 3
IM-S10-25
© Copyright 2005
1
For the DP17R:
Isolate the actuating air supply.
For the 37D:
Allow the sensor bulb to cool before
dismantling the valve.
6. Unscrew the unions and release the
pipework.
7
7. Unscrew the nuts.
8. Remove the pilot valve housing.
8
6
12
For the DP27, DP27E, DP27G and DP27Y:
Isolate the reducing valve and zero the
pressure.
For the DP27R:
Isolate the actuating air supply and zero the
pressure.
10
11
9. Unscrew the unions and release the
pipework.
10. Unscrew the spring housing securing nuts.
11. DP27, DP27E, DP27G and DP27Y:
Remove the pilot valve housing, complete
with the spring housing assembly.
DP27R:
Remove the pilot valve housing, complete
with the air control block.
12. Remove the main valve screen and clean
or replace as is necessary.
2
9
12
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IM-S10-25 CH Issue 3
For the DP143, DP163 and SDP143:
Isolate the reducing valve and zero the
pressure.
13. Undo the union nuts and release the 6 mm
stainless steel pipework.
14. Undo the nuts and remove the pilot valve
block complete with the spring housing
assembly.
13
13
14
For all DP valves and variants:
15. Remove the main valve spring and the
main valve head. Clean to remove dirt or
scale as necessary.
16. Remove the main valve seat. Clean and remove dirt and scale as necessary.
Note: Examine the faces of the main valve head and seat. If they are only slightly worn they
may be lapped on a flat plate using a fine grinding paste. If either is badly worn or unfit for
further use they must be replaced.
DP_G variants
If there is wear or damage to the nitrile face then the head assembly must be replaced.
17. Refit the valve seat applying jointing compound to the seating faces and tighten to the
recommended torque shown in Table 1.
Note: A special seat removal / replacement tool is available from Spirax Sarco.
Table 1 Recommended tightening torques for the main valve seat
Size of valve
½" and ½" LC
DN15 and DN15LC
¾" and DN20
1" and DN25
DN32
DN40
DN50
DN80
IM-S10-25 CH Issue 3
Width across flats
Tightening torques
Nm
(lbf ft)
30 mm A /F (External)
110 - 120
36 mm A /F
19 mm A /F
24 mm A /F
30 mm A /F
41 mm A /F
N /A
140
230
300
450
620
600
(External)
(Inside)
(Inside)
(Inside)
(Inside)
-
150
250
330
490
680
700
(81 - 89)
(103
(170
(221
(332
(456
(443
-
111)
184)
243)
361)
502)
516)
3
Where a new seat or head has been fitted or the main diaphragm plate and pushrod assembly
is to be renewed it will be necessary to reset the main valve pushrod to give the correct valve
lift. To do this it is necessary to expose the main diaphragm plate and pushrod assembly.
18. Undo the long nut and pull away.
19. Undo the M12 nuts and bolts.
20. Drop away the lower diaphragm chamber,
the two diaphragms, diaphragm plate and
pushrod assembly.
Table 2
Recommended valve lift settings
Size of valve
19
Valve lift
DN15
2.0 mm
DN20
2.5 mm
DN25
3.0 mm
DN32
3.5 mm
DN40
4.5 mm
DN50
5.0 mm
DN80
8.0 mm
18
22
23
20
21. Refit or replace the diaphragm plate and
pushrod assembly.
22. Refit the main valve head making sure
that the valve head locates on the seat.
23. Check the valve lift shown in Table 2 using
a depth gauge. Adjust if necessary by
screwing the pushrod in or out of the
diaphragm plate, when the desired length
is established apply locking torque as
listed in Table 3.
4
21
Table 3
Recommended tightening
torques for pushrod lock-nut
Size of valve
Nm
(lbf - ft)
DN15, DN20
15 - 20
(11 - 15)
DN25, DN32
25 - 30
(19 - 23)
DN40, DN50
45 - 50
(33 - 37)
DN80
60 - 70
(45 - 52)
IM-S10-25 CH Issue 3
24. Thoroughly clean the upper and the lower diaphragm chamber contact faces.
25. Replace the diaphragm plate and pushrod assembly and loosely fit the lower diaphragm
chamber using the bolts either side of the union connection to locate the spigot in the recess.
26. Bring the two new diaphragms together (where precoated sealant is applied this should face
outwards) and slide into position or refit in exactly the same way as when dismantled.
26
24
25
27. Push the lower diaphragm chamber home to locate in the recess and refit the M12 nuts
and bolts. Progressively and evenly tighten to a torque of 80 - 100 N m (59 - 74 lbf ft).
28. Retighten the long union nut to ensure a steam tight seal.
28
27
29. Refit the main valve head.
30. Replace or renew the main valve return spring.
31. Fit the new gasket.
30
31
29
IM-S10-25 CH Issue 3
5
32. DP and all derivatives except R - Assemble the pilot valve housing complete with the
spring housing assembly and tighten the nuts to the recommended torques shown in
Table 4.
For the DP17R and DP27R - Assemble the pilot valve housing complete with air control
block and tighten the nuts to the recommended torques shown in Table 4.
32
33
33
DP17 shown
33. Refit the pipework and retighten the unions to ensure a tight seal.
Bring the valve back into commission by following the instructions below.
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IM-S10-25 CH Issue 3
Table 4 Recommended tightening torques for the pilot valve block
securing nuts.
DP143, DP163, SDP143 and derivatives:
Size of valve
Nut size
DN15LC, DN15 and DN20
DN25 to DN50
Note: for DN40 and DN50 valves predating 1996:DN80
M10
M12
M16
M12
Tightening torque
Nm
(lbf ft)
40
(30)
60
(44)
110
(81)
80
(59)
DP17, DP27 and derivatives:
Size of valve
Nut size
DP15, DN20, DN25 and DN32
DP40 and DN50
M10
M12
Tightening torque
Nm
(lbf ft)
40
(30)
45
(33)
Commisioning
Start-up (Setting the valve)
1. Ensure that all connections are properly made and that all valves are closed.
2. Check that the adjustment is turned fully anticlockwise until the spring is slack.
3. Open the small valve in the pressure control line.
4. Blow through the approach pipework by removing the cap and screen from the strainer
protecting the steam trap draining the upstream pipework. Replace upon completion. Do not
remove the screen from the main line strainer during this operation. Although this should
remove most of the dirt which is present, it may be necessary to examine and clean the main
line strainer at regular intervals.
5. Slowly open the upstream isolating valve until it is fully open.
6. Using a 19 mm A / F spanner slowly turn the adjustment screw in a clockwise direction until
the desired downstream pressure reading is obtained.
7. Holding the adjustment screw in position with the spanner tighten down the lock-nut to
secure the setting of the adjustment spring, making sure that the 'C' washer stays in position
(Figure. 1).
8. Slowly open the downstream valve until it is fully open.
IM-S10-25 CH Issue 3
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IM-S10-25 CH Issue 3
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