| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve device which conducts valve opening operation without abnormally increasing the pressure in a valve casing and requiring large operation force. SOLUTION: A marking for indicating a rotating position of a handle 12 when a valve element 4 is changed from a fully closing state to a specified opening state (semi-fully closing). By matching the marking, the valve element 4 is operated from a position in the fully closing state to a position in the specified opening state (semi-fully closing) without a burden. Valve opening operation can be conducted without abnormally increasing the pressure in the valve casing 8 and requiring large operation force, and the fully closing state of the valve is ensured. COPYRIGHT: (C)2003,JPO
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