| 摘要 |
PROBLEM TO BE SOLVED: To concurrently satisfy wear resistance, tensile strength, and tear strength in the physical characters of a seat ring of a conventional butterfly valve, elongate service life of the seat ring, and provide more positive sealability by a comparatively simple structure. SOLUTION: The butterfly valve is composed of a valve body 1 comprising a rigid material piercing a cylindrical fluid channel, a discoidal valve element 3 comprising a rigid material rotatably journalled inside the valve body 1, and the seat ring 2 comprising an elastic material stretched between the valve body 1 and the valve element 3. Both side end faces d of the seat ring 2 provided on the valve body 1, and outer circumferential faces e and inclined faces f of both side end faces are integrated with the valve body 1. A gap part 5 is provided between the valve body 1 and cylindrical outer circumferential faces formed in inner end parts of both inclined faces f of the seat ring 2. A conduit 6 supplying and discharging operating fluid is communicated with the gap part 5. Reinforcing woven fabrics 2a are concurrently formed in a back side of the seat ring 2 in portions not pressed against the valve element during valve closing.
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