BUTTERFLY VALVE, SEAT RING FOR BUTTERFLY VALVE, AND METHOD FOR MANUFACTURING SEAT RING

摘要

PROBLEM TO BE SOLVED: To provide a butterfly valve in which a seat ring is prevented from moving in a valve main body to eliminate generation of fluid leak in the butterfly valve, or torque increases to cause trouble in use because the seat ring including a core moves in the valve main body in the butterfly valve.;SOLUTION: This butterfly valve is a circular body comprising a circular core 51 of hard material integrated with a coating layer of elastic material coating the core. The core is provided with a swollen part 54 extended in a circumferential direction on an outer circumferential surface, and step parts 511 and 512 are provided on both sides of the swollen part to direct outward to provide the seat ring 5. For a fluid passage in the valve main body 1, a wall surface is provided to be tightly applied to the outer circumferential surface from one side of the seat ring through one step part of the two step parts to reach the swollen part. In a surface to face the other parts of the seat ring from the other step part, a cut part 12 is provided to be extended in the circumferential direction. After the seat ring is inserted, a presser plate 6 is inserted into the cut part, and the presser plate is applied to the other step part to be fixed to the side of the valve main body.;COPYRIGHT: (C)2004,JPO&NCIPI