BRONZE GATE VALVES Introduction

BRONZE GATE VALVES Introduction
Help
BRONZE GATE VALVES
Introduction
?
BASIC DESIGN
Gate valves offer the ultimate in dependable service wherever minimum pressure drop is important. They
serve as efficient stop valves with fluid flow in either direction.
The straight through design offers little resistance to flow and reduces pressure drop to a minimum. A
gate-like disk - actuated by a stem screw and handwheel - moves up and down at right angles to the
path of flow, and seats against two seat faces to shut off flow.
Gate valves are best for services that require infrequent valve operation, and where disk is kept either
fully opened or closed. They are not practical for throttling. With the usual type of gate valve, close
regulation is impossible. Velocity of flow against a partly opened disk may cause vibration and
chattering, and result in damage to the seating surfaces. Also, when throttled, the disk is
subjected to severe wire-drawing erosive effects.
Bodies are designed to eliminate sharp contours, thus giving the entire valve more rigidity under line
strains, providing maximum strength and increased resistance to shock and distortion and especially
reinforce seats against the wedging action of the disk. Bold wide faced hexagon ends on threaded
valves provide a firm wrench grip and prevents damage to the valve.
P
Body to bonnet connection is designed to suit the pressure rating of each valve. Lower rated valves will
have screwed-in bonnets and higher rated valves utilise either a union ring type connection or on larger
sizes, a bolted bonnet. PN16 and PN2O valves and larger sizes of valves in higher pressures normally
have a gasketted joint, but other valves have accurately machined joints which provide exceptional
metal-to-metal tightness.
In accordance with BS 5154, Series A gate valves with rising stems are constructed so that the gland
packing can be replaced when the valve is fully open, i.e. back-seated, and under full working pressure.
If other valve types are required with a backseating facility, users must contact their distributor to check
if valves are suitable. Users are recommended to take suitable precautions when making use of this
facility, especially on steam or high temperature hot water services.
A
G
E
MANUFACTURING STANDARDS
Threaded Valves
Valves with ends threaded BS 21 (ISO 7) or ANSI B1.20.1 (formerly ANSI B2.1) are identified by their PN
rating and comply with BS 5154. All pipe end threads are taper type.
Flanged Valves
Valves with BS 4504 metric flanges are PN rated and conform to BS 5154.
Valves with ANSI flanges are Class rated and conform to BS 5154.
Valves with BS 10 flanges are Class rated and conform to BS 1952.
Pressure/temperature ratings and test pressures for ANSI threaded and flanged valves generally exceed
the requirements of MSS SP 80 for the equivalent Class of valve.
BACK TO
PLEASE SEE FOLLOWING PAGES FOR FURTHER INFORMATION
CATALOGUE
BRONZE GATE VALVES
Introduction
MATERIALS AND CONSTRUCTION
1. Body is made of cast bronze, pressure diecast Ametal or forged
brass dependent on valve size/rating. Like all parts, bodies are
designed to withstand high internal pressures and line strains
and are proportioned to assure a high safety factor under
recommended working conditions. Body seats are integral and
accurately tapered to ensure perfect shut off without strain.
2. Bonnet is made of cast bronze, pressure diecast Ametal or
forged brass depending on valve size/rating.
Screwed bonnet provides a dependable low cost body bonnet
construction.
Union bonnet for higher pressure valves facilitates dismantling
and reassembly.
Bolted bonnet on larger valve sizes is compact, dependable
and maintains a strong joint, yet can be dismantled without
damage to the valve.
3. Bonnet gasket provided on Cat. Nos. D151A, D155, D156,
D237A and D255 and larger sizes of other valve ranges is of
high grade compressed asbestos.
A
G
4. Disk is made from high grade materials especially selected to
perform dependably on the services for which the valve is
recommended. All disks are wedge pattern, either solid with
slip on ‘T’ connection to the stem or hollow threaded for nonrising stem valves.
Gate Valve, Rising Stem, Union
Bonnet, Solid Wedge Disk
P
E
5. Stem is made from high grade materials especially selected to
perform dependably on the services for which the valve is
recommended. Stem threads are accurately machined of the
Acme form and full thread engagement with the disk or bonnet
is always assured.
6. Stem retaining ring on Cat. Nos. D151A, D151X, D155, D156,
D237A and D255 valves retains the stem in the bonnet. It is
screwed in and locked in position but ensures free rotation of
the stem. Material is brass, Ametal or bronze.
7. Union bonnet ring is made of cast bronze and reinforces the
body-bonnet joint.
8. Stuffing box is amply deep and packed with quality packing to
assure a tight stem seal.
9. Packing. Gland packing fitted to most CRANE bronze gate
valves is a high quality preformed ring of asbestos with graphite
and suitable binders but certain valves have high grade
graphited asbestos yarn packing. Valves required for petrol and
hydrocarbon services may require special petrol type packing.
Individual data pages will state when packing for petrol service
needs to be specified. Cat. Nos. D151A, D155, D156, D237A
and D255 valves have PTFE impregnated asbestos packings.
10. Gland machined from brass bar.
11. Packing nut machined from brass bar.
12. Handwheel - Cat. No. D278 pressure die cast aluminium
handwheels are normally fitted but some large size gate valves
have Cat. No. D280 cast malleable iron wheels.
Gate Valve, Non-Rising Stem,
Screwed Bonnet, Wedge Disk
BACK TO
13. Handwheel nut - Brass or steel.
14. Identification plate - Aluminium.
CATALOGUE
BRONZE GATE VALVES
Introduction
SERVICE RECOMMENDATIONS
All valves are recommended for non-shock, steam, water, oil or gas within the material and pressure/
temperature limitations of the valve.
Valves rated PN16 and PN20 are widely used in domestic and commercial plumbing and heating systems
and condensate lines.
Valves in the Cat Nos D151A, D151X, D155, D159 and D255 ranges are particularly suited to soft water
and other aggressive duties where dezincification and other forms of corrosion may be a problem.
Prior to 1985 certain valves used within the Thames Water Authority’s Metropolitan Water Division
(formerly Metropolitan Water Board) had to be tested and stamped by MWD. Such valves were used on
closed water installations and for above ground hot and cold water supply services. Current TWA
requirements stipulate that valves shall conform to the JWA Byelaws and also the relevant British
Standard. In addition valves should be listed by the Water Research Centre Water Byelaws Advisory
Service (WBAS) (formerly NWC Listed) and where possible be BSI Kitemark approved. D159, D235,
DM160, DM161, DM258 and DM259 valves are currently WBAS listed.
Valves in the Cat. No. D180 range are particularly suited to handling severe services at temperatures up
to 260ºC (500ºF). These valves have Nickel Alloy wedges which are highly resistant to erosion and
corrosion.
P
A
Standard preformed graphited asbestos gland packing is suitable for petrol and other hydrocarbon
services. Some valves which have graphited asbestos yarn packing require special packing for use on
petrol service. Individual data pages will state when petrol service need to be stated on purchase orders.
G
E
SELECTION GUIDE
END CONNECTIONS
Type
THREADED
Rating
Standard PN
PN 16
PN 20
BS
21
PN 25
or
PN 32
ANSI
B1.20.1 PN 40
PN 64
BS
PN 16
4504
PN 25
ANSI
B16.24
FLANGED
BS
10
COMPRESS- BS
ION
864
SOLDER
BS
864
Class
(100)
(125)
(150)
(200)
DESIGN & CAT. No.
Screwed-in Bonnet
Non-Rising Stem
Rising Stem
D156
D151 D237
D151A D237A
D151X
D159
D166
D235
(250)
(300)
150
Union Bonnet
Rising Stem
D180
D185
DM160 DM258
DM 161 DM259
D162 D167
100
D160 D258
(Tab.E)
150
D161 D259
(Tab.F)
PN 20 (125)
D155C
D255C
PN 20 (125)
D155S
D255S
Valves Threaded ANSI - Add 'AT' to Cat. No.
BACK TO
CATALOGUE
BRONZE GATE VALVES
Threaded BS21 or ANSI B1.20.1
SOLID WEDGE DISK
NON RISING STEM
SCREWED-IN BONNET
PN16
PRESSURE/TEMPERATURE RATINGS
BS 5154 SERIES B
D156
P
A
TESTING
Each valve individually tested to BS 5154.
G
SPECIFICATION
D156 - Sizes 1/4 to 4 - Threaded BS21 (ISO 7) taper.
Valves sizes 1/4 to 2 are manufactured in accordance with
BS 5154 PN 16 for Series B ratings.
Sizes 2 1/2 to 3 valves with brass body material and size 4
valves are not covered by BS 5154 but valve construction
conforms to BS 5154 as far as applicable.
Valves detailed on this page are expressed in metric terms, but are
equally suitable for use in Class 100 imperial systems specifying
valves to BS 1952 at the following ratings:200 lbf/in2 CWP 100 lbf/in2 at 339ºF.
E
MATERIALS
Part
Body
Bonnet
Disk
Stem
SIZE
in
1/4
3/8
1/2
3/4
1
1 1/4
1 1/2
2
2 1/2
3
4
Material
60/40 Brass
60/40 Brass
60/40 Brass
60/40 Brass
DIMENSIONS
mm
A
B
41
67
41
67
48
69
54
80
62
92
68
108
72
121
82
151
97
177
111
202
131
252
BS
BS 2872
BS 2872
BS 2872
BS 2874
H
44
44
44
52
52
65
70
92
103
120
152
CZ
CZ
CZ
CZ
in
A
1.61
1.61
1.89
2.13
2.44
2.68
2.84
3.23
3.82
4.37
5.16
122
122
122
121
ASTM
B 124 Alloy 377
B 124 Alloy 377
B 124 Alloy 377
B 16 Alloy 360
WEIGHT
kg
B
2.64
2.64
2.72
3.15
3.62
4.25
4.76
5.94
6.97
7.95
9.92
H
1.75
1.75
1.75
2.06
2.06
2.56
2.75
3.63
4.06
4.75
6.00
0.21
0.20
0.24
0.37
0.57
0.75
0.99
1.59
2.54
3.65
6.36
BACK TO
CATALOGUE
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement