| 摘要 |
<p>A check valve assembly for preventing back flow in a flow path when regular flow pressure drops to a predetermined level, said check valve assembly comprising on upstream body member of a generally cylindrical shape having an upstream opening at an upstream side adapted to sealingly engage a flow line, and having a mating portion with an opening at a downstream side, a downstream body member of a generally cylindrical shape having a downstream opening at a downstream side adapted to sealingly engage a flow line, and having a mating portion with an opening at an upstream side. Whereby said upstream and said downstream body members are joined at said mating portions, respectively, in sealing engagement thereby forming a closed body which forms part of said flow path. A generally ring-shaped seating member having a passage therethrough and positioned within said closed body, formed from a unitary piece of material, comprising a flat base surface positioned in said closed body 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 to rest in the closed position.</p> |
