wedge gate valves

Wedge gate valve after a panting process

Gate valves -often known as sluice valves- opens by lifting a gate with wedge shape, out of the path of a fluid. The sealing surface in between the gate and seats are planar, and once lifted, there are not obstructions in the flow path, so they are used when a minimum friction is required.

Wedge gate valves may have a screw-in union, or a bolted bonnet. The first one is the simplest, offering a long lasting seal. The bolted bonnet is used large valves that works under higher pressures.

Babcock Valve’s wedge gate valves are made from carbon, alloy and stainless steel, bolted joint between bonnet and body, outside screw and yoke, threaded, welded or integral seal.

PARTS OF A WEDGE GATE VALVE

assemb gate valve 2001 Body

Available both in cast and forged steel, it has been designed to meet all the requirements of ASME, API and British Standards

The body-bonnet connection is made by a pressure seal gasket. Its pre-stress condition is achieved by means of bolts screwed to the bonnet flange.

Ends are normally butwelding although they can be also flanged on request.

All bodies are provided with integrally cast bosses, located and sized in accordance with ASME B16.34, which allow the provision of drain and by-pass connections, supplied on request.

2 Bonnet

Usually constructed in the same materials as the body, being designed so that the wall thickness always exceeds the requirement of API 600.

A back seat bush (13) is fitted inside the bonnet lower cavity, to provide a closure when de valve is fully opened. This permits the valve to be repacked while in service.

The bonnet has a deep stuffing box in which packing rings are placed.

Stuffing box is designed with sufficient space to allow lantern ring to be fitted.

3 Yoke

Separate rigid yoke provided to withstand the thrust of the actuator. Large windows allow easy access and ventilation of the packing area. The yoke is connected to the body by a two piece clamping ring (193) an four clamp bolts. This connection is very solid and enables easy maintenance at site.

The upper part of the yoke is suitably machined to house the yoke sleeve (11).

The yoke is usually made of cast carbon steel regardless the type of body material, unless otherwise required by the client.

4 Stem

Constructed in stainless steel, machined from solid bar stock. The single piece stem in connected to the wedge by a tee connection.

A conical shoulder is also provided to ensure effective and tight seal backseat which allows the stuffing box to be replaced with the valve in service. The stem dimensions conform to API 600. Connection stem-wedge also meets the requirements of API 600. Pull test has been carried out to verify the design. Special care is taken in the machining of the stem, including the final polishing of the travelling area (contact with the stuffing box). This allows a low-friction surface and a superior corrosion resistance.

22-128 Gland bolts and nuts

The gland studs are of the eyebolt type, which can be swing outwards for ease of gland repacking.

6 Seat rings

They are supplied in forged stainless steel, hardfaced with Stellite-6 (2 mm of minimum thickness). Seat rings are renewable, normally welded to the body.

Sealing contact surfaces, are lapped for a perfect tight seal. Controlled hardness differentials are maintained between the wedge discs and the seat rings, as required by API 600 Std.

7 Wedge

The wedge is normally constructed in forged stainless steel for diameters up to 3”, and in cast steel for larger sizes.

Wedge is commonly flexible, though it can be also solid. Guides are carefully machined for a smooth sliding in the body cast-in guides.

Contact faces are overlayed with stellite-6 (2 mm. ominimumn. thickeness).

193 Yoke clamp

The connection between body and yoke is created by means of a bipartite clamping ring. The internal connection between the clamp, body and yoke is conical, assuring a perfect tightening.

11 Yoke sleeve

Designed to permit removal from the bonnet or yoke while the valve is in service.

The yoke bushing assembly is mounted in ball bearings. It is normally made of cast aluminium bronze, having high resistance to wear and high melting point. Other materials such as

Ni-resist can be supplied on request.

13 Back seat

The back seat can be supplied as a threaded stainless steel bush, welded to the bonnet or of integral type. It can be hardfaced with Stellite-6 or orther materials as required.

This seat allows the valve to be repacked under pressure.

15 Handwheel

The handwheel can be supplied either in cast construction of fabricated from steel tube.

The handwheel is designed to allow easy operation of the valve. Other types of control are available and, in some cases, are indispensable for a good operation, for instance:

  • Chain wheel
  • Gear operator
  • Hammer handwheel
  • Geared hammer handwheel
  • Electric actuator
  • Electro-hydraulic actuator
  • Pneumatic actuator

134 Bonnet retainer

Designed sufficiently resistant to withstand the forces transmitted by the bonnet screws (111).

The bonnet retainer is normally made of the same material as the body, but it can be constructed in any other material on request. It is machined to match exactly with the body, what guarantees a perfect alignment of the unit.

Gate valve spacer ring132-Spacer ring

Made of a single piece coverting the upper part of the pressure seal gasket. It is normally manufactured in the same material as the body.

133 Gasket retainer

It is made normally of the same material as the body, and constructed in four pieces, called segments. The segments are sized to minimize the gap among them.

The segmental ring supports all the forces transmitted from the bonnet through the spacer ring. It is calculated to withstand all the force without cracking.

17 Pressure seal gasket

The pressure seal gaskets are usually supplied of compressed graphite, bordered on the upper and lower edges with braided filaments of graphite and Inconel.

Gaskets can also be made in stainless steel.

5-125 Gland bushing and gland flange

They are supplied in two separate self aligning pieces, to ensure uniform pressure is effected during tightening of the packing.

The upper part of the gland, which comes in contact with the gland flange, is spherical in shape.

The gland flange is made of carbon steel but, upon request, other materials can be supplied.

68 Packing

Packing is made of an adequate number of preformed rings.

For general applicatios high grade graphite material is supplied, using compressed rings in the center and braided anti-extrusion rings on top and bottom. Graphite is selected of an approved quality.

Other types of packing are also available for particular services.

Flexible wegde gate valve

Flexible wegde gate valves


STANDARD MATERIALS

Part
Denomination
Carbon
steel
Alloy
steel
Stainless
steel
1
BODY
ASTM A 216 WCB
ASTM A 217 WC9
ASTM A 351 CF8M
2
BONNET
ASTM
A 105
ASTM
A 182 F22
ASTM
A 182 F316
3
YOKE
ASTM
A 216 WCB
ASTM
A 216 WCB
ASTM
A 216 WCB
(4
STEM
ASTM
A 182 F6A
ASTM
A 182 F6A
ASTM
A 182 F316
5
GLAND
ASTM
A 182 F6A
ASTM
A 182 F6A
ASTM
A 182 F316
() 6
SEAT
RING
ASTM
A105+STELLITE
ASTM
A182F22+STELLITE
ASTM
A351CF8M+STELLITE
() 7
WEDGE
ASTM
A216WCB+STELLITE
ASTM
A217WC9+STELLITE
ASTM
A351CF8M+STELLITE
11
YOKE
SLEEVE
ALUMINIUM-BRONZE
ALUMINIUM-BRONZE
ALUMINIUM-BRONZE
() 13
BACK
SEAT
ASTM A105+STELLITE
ASTM
A182F22+STELLITE
ASTM
A182F316+STELLITE
15
HANDWHEEL
CARBON
STEEL
CARBON
STEEL
CARBON
STEEL
17
PRESSURE
SEAL GASKET
COMPRESSED & BRAIDED
GRAPHITE
COMPRESSED & BRAIDED
GRAPHITE
COMPRESSED & BRAIDED
GRAPHITE
20
SLEEVE
NUT
CARBON
STEEL
CARBON
STEEL
CARBON
STEEL
22
GLAND
NUT
ASTM
A 194 2H
ASTM
A 194 2H
ASTM
A 194 2H
24
YOKE FLANGE
CARBON
STEEL
CARBON
STEEL
CARBON
STEEL
68
INTERMEDIATE
PACKING
GRAPHITE
GRAPHITE
GRAPHITE
68A
END
PACKING
BRAIDED
GRAPHITE
BRAIDED
GRAPHITE
BRAIDED
GRAPHITE
75
BEARING
COMMERCIAL
COMMERCIAL
COMMERCIAL
111
YOKE
FLANGE CAP SCREW
AISI
4140
AISI
4140
AISI
4140
111A
BONNET
CAP SCREW
AISI
4140
AISI
4140
AISI
4140
118
GLAND
RETAINER CAP SCREW
AISI
4140
AISI
4140
AISI
4140
125
GLAND
FLANGE
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
127
YOKE
CLAMP STUD
ASTM
A 193 B7
ASTM
A 193 B7
ASTM
A 193 B7
128
GLAND
BOLT
ASTM
A 193 B7
ASTM
A 193 B7
ASTM
A 193 B7
129
YOKE
CLAMP NUT
ASTM
A 194 2H
ASTM
A 194 2H
ASTM
A 194 2H
132
SPACER
RING
ASTM
A 105
ASTM
A 182 F22
ASTM
A 182 F316
133
GASKET
RETAINER
ASTM
A 105
ASTM
A 182 F22
ASTM
A 182 F316
134
BONNET
RETAINER
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
193
YOKE
CLAMP
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
194
GLAND
RETAINER
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
ASTM
A 515 Gr 70
195
GREASE
FITTING
COMMERCIAL
COMMERCIAL
COMMERCIAL

 

OTHER MATERIALS

Other materials are available on request. The trim () components are:

  • Stem
  • Seat ring seating surfaces
  • Wedge seating surfaces
  • Back seat seating surface

 

ASME CLASS

Asme class for valves

Notes

  • Ends to end dimensions are for short pattern, long patterns are available on request.
  • The valve weight is for Butt Welding ends.
  • Dimensions in mm. and weights in kg.
  • Dimensions not shown for classes 2500 and 4500 to customer requirements

 

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