Check valve and check valve seat

A seat and flapper assembly for use in a check valve having a housing with an upstream side and a downstream side, wherein said check valve is adapted to prevent backflow in a flow path when upstream regular flow pressure drops to a predetermined level, said assembly comprising: a generally ring-shaped seating member having a passage therethrough and positioned within said housing such that said passage forms part of said flow path, said seating member formed from a unitary piece of material and comprising a flat base surface positioned in said housing with said flat base surface facing upstream, an upward-angled planar top sealing surface and connector means formed on said top planar surface for connecting a moveable 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 lid to rest in the closed position. The invention includes a check valve assembly incorporating the seat and flapper assembly.