Patent ID: 6135416
Filing Date: 2000-10-24
Classification: F16K

Abstract:
A butterfly valve comprising:a valve housing having a fluid conduit and defining a valve seat;a seal plate assembly including a seal plate; anda closure assembly for moving said seal plate between an open position, an intermediate position wherein said seal plate is retracted from said valve seat, and a closed position wherein said seal plate is in sealed engagement with said valve seat, said closure assembly comprising:a main shaft mounted in said valve housing and rotatable about a longitudinal axis thereof, said main shaft comprising a flat surface;a first stop mounted to said valve housing for engaging said flat surface on said main shaft when said main shaft is rotated to a first position corresponding to the open position of said seal plate;a second stop mounted to said valve housing for engaging said flat surface on said main shaft when said main shaft is rotated to a second position corresponding to the intermediate position of said seal plate;a crank shaft concentrically positioned within said main shaft and rotatable about said longitudinal axis;a hub affixed to said main shaft and rotatable with said main shaft, said hub being movably coupled to said seal plate assembly to permit translation of said seal plate assembly with respect to said hub;a roller mounted to said crank shaft for eccentric rotation about said longitudinal axis, said roller engaging said seal plate assembly; andone or more springs mounted between said seal plate assembly and said hub for biasing said seal plate toward the intermediate position from the closed position, and retracting said seal plate toward the main shaft.