Swing check valve

摘要

A check valve has a valve body with an annular seat surrounding the duct and a flap member pivotally mounted on the valve body so as to pivot about an axis transverse to the duct from an open position to a closed position pressing against the seat. The flap member includes a circular flap plate with a rigid backer plate and a front resilient layer carried on a pivot mounting bracket having a rigid mounting plate generally parallel to the backer plate. The backer plate and the mounting plate each have a central hole therethrough and are connected by an integral body molded from a resilient elastomeric material to form the front resilient layer, a back stopper portion and a connecting neck portion arranged so as to provide resilient flexing movement between the flap plate and the mounting bracket. The mounting bracket is carried on a shaft with a pair of coil springs housed in a receptacle separated from the duct so that broken spring parts do not enter the fluid in the housing. The mounting bracket can carried on the main valve body separate from the cover so that the receptacles housing the springs and accessible from the exterior, or the receptacles may be on a second insert or cover piece so that they slide into place and are closed at the end by an outer surface of the main body portion.