| 摘要 |
PROBLEM TO BE SOLVED: To smoothly move a valve element at the beginning of rotation start. SOLUTION: In this emergency cutoff valve 1 provided with a valve stem 5 integrally rotated with the valve element 2 of a rotating valve, an arm 7 and a weight 6 which are vertically rotatable, and a holding means 10 preventing the lowering of the weight 6, the arm shaft 17 of the arm 7 is coaxially arranged on the periphery of the valve stem 5 and a key 18 and a key groove 19 are engaged with each other. When canceling prevention of lowering the weight 6 by the holding means 10, the valve stem 5 starts to interlock with the arm shaft 17 after the arm 7 is rotated downward by a play angleαfrom the lowering prevention state. After starting interlocking, the valve stem 5 is rotated to a valve closing state. Therefore, immediately after canceling the prevention of lowering, the weight 6 is swiftly lowered, and the arm 7 can be quickly rotated. Also, when the valve stem 5 starts to rotate, the weight 6 is already swiftly lowered. Therefore, the valve stem 5 can be quickly rotated by being applied with impact. COPYRIGHT: (C)2009,JPO&INPIT
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