| 摘要 |
A check valve assembly for use in backflow prevention apparatus for installation between a supply pipe and a discharge pipe comprises a stationary valve seat 25, a stationary barrel 21 positioned coaxially of said valve seat, a valve poppet 28 guided for movement in said barrel toward and away from said valve seat, a spring 33 acting to move said valve poppet into sealing contact with said valve seat, means cooperating with said barrel and said valve poppet to define a chamber 53 remote from said valve seat, and an ejector nozzle 44 on said valve poppet receiving fluid flow from said barrel when said valve poppet has separated from said valve seat, the outer surface of the valve poppet having a formation which in cooperation with said barrel produces circumferential flow of fluid on the outer surface of said valve poppet away from said ejector nozzle whereby to minimize axial flow from said valve seat along said valve poppet into said chamber, said ejector nozzle having a portion communicating with said chamber so that relatively rapid fluid flow from said ejector nozzle causes a reduction in fluid pressure in said chamber to oppose the action of said spring. <IMAGE> |
