| 摘要 |
A flapper or wafer-type check valve with two half-disc flapper or wafer closure elements pivotally mounted in the valve body by hinges on a shaft extending transversely of the valve's flow passage, and shaft guides that removably but securely retain the shaft in the valve body while facilitating limited movement of the shaft parallel to the flow passage axis. The curved and straight peripheries of the flappers close against a seat on the valve body comprising an annular shoulder extending into the flow passage and a transverse rib that extends across the flow passage parallel to the shaft. When opening from a closed position, the flappers first lift off the seat in the area of the hinges before they begin to pivot about the shaft, and as the flappers close they come to rest against the hinge area of the seat without sliding or rubbing against it, thereby avoiding wear of the seat. In addition, several different systems for securing the shaft guides to the valve body are disclosed, as are valves with resilient seats mounted on the flappers, on the valve body, and also valves with non-resilient seats.
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