Cast Steel Lift Check Valve / Piston Check Valve
Lift check valves are also called piston check valves. They are essentially globe valves without the stem and top works, allowing the disc to respond to flow rates and direction. The disc has linear movement and is typically body-guided with conical seating surfaces. Springs can be added above the disc to provide more closure force when the disc returns to its closed position. Some manufacturers include externally attached equalizer piping to increase the disc opening with lower flows. The equalizer pipe is an open-pressure communication device that maintains equal pressure above the disc and in the piping downstream of the disc.
Applicable Standards of Cast Steel Lift Check Valves:
a) Design&Manufacture: API 6D, BS 1868, ASME B16.34
b) Face to Face: API 6D, ASME B16.10, EN 558
c) Connection End: ASME B16.5, ASME B16.25, EN 1092, JIS B2220
d) Test and Inspection: API 6D, EN 12266, API 598, BS 6755