摘要 |
A check valve has a valve body and flapper. The flapper has a gasket which is sandwiched between a flapper base and a flapper cover. The flapper base has a flapper base stem which extends through an aperture in the gasket is retained within an aperture in the flapper cover. A central recess is defined in either the forward surface of the flapper base or the forward surface of the flapper cover to allow liquid which leaks between the flapper base and the gasket to migrate to the flapper base stem, and subsequently along the flapper base stem to the external side of the flapper cover. In this way, the flapper is capable of relieving pressure build-up between the gasket and the surface of the flapper base.
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