| 摘要 |
PROBLEM TO BE SOLVED: To provide a good sealing property for long period with a simple structure by arranging a seat ring whose center part is formed of a rubber elastic body, covering a part which is brought into contact with at least a fluid of a surface of the rubber elastic body with a seat made of polytetrafluoroethylene, and arranging a lip part which is annularly protruded to an inner circumferential surface. SOLUTION: A seat ring 31 is composed of a rubber elastic body 33 fixed to an inner surface of a stainless made angle shaped mandrel 32, and a polytetrafluoroethylene(PTFE) made seat 34 stuck on the surface of the rubber elastic body 33 with special adhesive. A lip part 39 is arranged on an inner circumferential surface by annularly protruding. In the case where it is held in a valve box by a holding member, sealing property with the valve box is surely improved by compression force of the lip part 39. Thus the frictional resistance with a valve element is so small to produce excellent opening/closing operability of a valve, and manufacture is easy without increasing the number of part items, and excellent sealing durability is available.
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