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ANSI Valves -
Check Valve
 Applicable Standards
Design and Manufacturing
Cast Steel check valve to BS1868 ASME B16.34 and API 6D
Forged steel check valve to API 602.
Inspection and test: API 598 or API 6D
End flange dimension; ASME B16.5 (for NPS ≤ 24).
ASME B 16.47 series B, API 605 or ASME B16.47
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.
Wall thickness dimension: API 600 and BS1868)
The body and bonnet of Class150 - Clas900 check valves are usually with studs and nuts. And the body and bonnet of Class1500 - Class2500 check valves are usually of pressure seal design.
Seat
For carbon steel check 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 check valves, and welded on seat can be also optional if being requested by the customer. Welded on seat is used for NPS ≥ 12k carbon steel check valves. For stainless steel check Valve, integral seat is usually adopted, or weld hard alloy directly integrally. Threaded or welded on seat is also optional for stainless steel check valve if being requested by the customer.
Body-To-Bonnet Joint
Stainless steel + flexible graphite wounded gasket is used for Class150 and Class300 check valve; class 150, 300 and 600.
Ring joint gasket is also optional for Class 600 check valve; Pressure seal design is gasket is used for Class used for Class 1500 and Class 2500 check valves.
The features of a check valve
Bolted Bonnet;
Swing and lift type disc;
Metallic seating surfaces.
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