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ANSI Valves -
Gate Valve
 Technical specifications for Gate Valve
Design and Manufacturing
Cast steel gate valve
to API600
(ISO 10434) or API 6D; Cast stainless steel gate
valve to API
603 or API 600; Forged steel gate valve to API 602.
Inspection
and Test: API 598, API 600 or API 6D.
End flange dimension: ASME B16.5 (for NPS≤24) ; ASME
B16.47 series B, API 605 or ASME B16.47 series A,
MSS SP-44
(for NPS>24).
Body
and Bonnet Connection
BW end dimension: ASME
B16.25.
Socket-weld dimension: ASME B16.11.
Face to face and end to end: ASME B16.10.
Pressure-temperature ratings: ASME B16.34.
The body and bonnet of Class150 – Class900 gate
valves are usually connected with studs and nuts.
And the body and bonnet of Class1500 – Class2500
gate valves are usually of pressure seal.
Stem
Nut
Usually, the stem nut
is made of copper alloy. It is also can be made of
ASTM A439 D2 if being requested by the customer.
For large sized gate valves ( NPS 10 for Class 150,
NPS 8 for Class 300, NPS 6 for Class 600, NPS 5 for
Class 900), rolling bearing is fitted at the two
sides of the stem nut in order to minimize the open
and close torque of the gate valve.
Design of Disc
Gate Valves with NPS ≥
2 are of flexible wedge;
Gate valves with NPS < 2 are of solid wedge.
Actuation
Hand wheel or gear box
is usually used for gate valve actuation.Chain wheel
and electric actuator can be also used for gate
valve actuation if being requested by the customers.
Seat
For carbon steel gate
valve, the seat is usually forged steel. The sealing
surface of the seat is spray welded with hard alloy
specified by the customer. Renewable threaded seat
is used for NPS ≤ 10 gate valves, and welded on seat
can be also optional if being requested by the
customer.
Welded on seat is used
for NPS > 10 carbon steel gate valves. For Stainless
steel gate valve, integral seat is usually adopted,
or to weld hard alloy directly integrally. Threaded
or welded on seat is also optional for stainless
steel gate valve if being requested by the customer.
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