Check valve and check valve seat

摘要

The present invention is directed to a check valve assembly comprising an upstream body member and a downstream body member which are joined in sealing engagement to thereby form a closed body; a generally ring-shaped seating member formed from a unitary piece of material and comprising a flat base surface positioned in said closed body with said flat base surface facing upstream, a flat top surface parallel to said flat base surface, a flow passage extending from said base surface to said top surface and a bore extending into said top surface toward said base surface, said bore defining an annular lip surrounding said flow passage and a recessed upward-angled planar top sealing surface; said seating member further comprising a cut-out segment formed in said lip which defines two extensions projecting axially from the top sealing surface and a transverse hole in each extension through which a hinge pin is received to connect a movable flapper lid to said seating member; said flapper lid comprising a flapper sealing surface adapted to sealingly engage the top sealing surface of the seating member to stop backflow when said regular flow pressure from upstream drops to a predetermined level causing the flapper to rest in the closed position,