| 摘要 |
PROBLEM TO BE SOLVED: To provide a shut-off valve system of a drain pipe of a floating roof storage tank which is capable of quickly closing a shut-off valve in case of an emergency. SOLUTION: Drain pipes 40A, 40B of a storage tank 30 are provided with drain pipes 50A, 50B for use in draining rain water accumulated at the upper surface 22 of a floating roof 20, shut-off valves 60A, 60B for use in shutting off the drain pipes 50A, 50B, and shut-off valve driving units 70A, 70B for supplying gas pressure to actuators 62A, 62B of the shut-off valves 60A, 60B. The actuators 62A, 62B has a piston-cylinder mechanism. The shut-off valve driving units 70A, 70B discharge liquefied gas from liquefied gas bombs 160A1, 160A2 upon detection of occurrence of earthquake and supply the liquefied gas to the actuators 62A, 62B of the shut-off valves 60A, 60B. With this arrangement, pistons of the actuators 62A, 62B are driven and the shut-off valves 60A, 60B are closed with the driving force. COPYRIGHT: (C)2009,JPO&INPIT
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