| 摘要 |
PROBLEM TO BE SOLVED: To solve problems in two conventional methods for contraction of an inflate seal for releasing sealing of a valve, or low valve releasing speed of one method depending on the restoration force of the inflate seal, and necessity of preparation of a separate exhaust facility or an increased number of part items and low reliability of the other method of evacuating the inflate seal. SOLUTION: A hollow seal member expansible and contractible by introduction and discharge of a high-pressure fluid is provided on a valve element set in the clearance of a valve body or in the inside of a face of the valve body opposed to the valve element. The valve element or the face opposed to the valve element of the valve body is two-dimensionally changed in thickness by expansion and contraction of the seal member. In valve closing operation, the seal member stuck to the surface of the valve element or the face opposed to the valve element seals the space between both faces of a sealed part around a valve opening part in the clearance of the valve body and the valve element. In valve opening operation, the hollow seal member is rapidly exhausted by a discharge acceleration means. COPYRIGHT: (C)2008,JPO&INPIT
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