A swing check valve consists of a flap or disc which hangs down in the flow path. With flow in the forwards direction, the pressure of the fluid forces the disc to swing upwards, allowing flow through the valve. Reverse flow will cause the disc to shut against the seat and stop the fluid going back down the pipe. In the absence of flow, the weight of the flap is responsible for the closure of the valve.

Normative reference

API 602 Steel Gate, Globe and Check Valves for Sizes DN 100 and Smaller for the Petroleum and Natural Gas Industries

BS 5352 Specification for Steel Wedge Gate, Globe and Check Valves 50 mm and Smaller for the Petroleum, Petrochemical and Allied Industries

ASME B16.34 Valves Flanged, Threaded and Welding Ends


ASME B16.5 Pipe Flanges and Flanged Fittings: NPS 1/2 through 24


ASME B16.25 Buttwelding Ends
ASME B16.10 Face to Face and End to End Dimensions of Valves


ASME B1.20.1 Pipe Threads, General Purpose (inch)

ASME B16.11 Forged Steel Fittings, Socket-Welding and Threaded

MSS SP-25 Standard Marking System for Valves, Fittings, Flanges and Unions

Size available

NPS 1/2 to NPS 4 (DN15 to DN100)

Pressure rating available

Class 150 to Class 2500