| 摘要 |
<P>PROBLEM TO BE SOLVED: To adjust the air quantity so as to prevent an excessive negative pressure from acting on a leakage detection layer when a leakage inspection is implemented in a double shell tank. Ž<P>SOLUTION: A leakage inspection apparatus 10 includes: a piping route 20 connected to the leakage detection layer 100 of the dual shell tank 90 at one end; a depressurization pump 30 connected to the other and of the piping route 20; a pressure detector 40 provided in the middle of the piping route 20; an opening and closing valve 50 provided in the middle of the piping route 20; an air quantity adjusting valve 60; a throttle member 70; and a controller 80. When the opening and closing valve 50, the air quantity adjusting valve 60 and the throttle member 70 are opened and the depressurization pump 30 is activated, the leakage detection layer 100 is depressurized. When the degree of valve opening in the air quantity adjusting valve 60 and the throttle member 70 is throttled, a depressurization speed of the leakage detection layer 100 is adjusted to a low speed. If a predetermined time is elapsed, a pressure detection signal is detected by the pressure detector 40, and read. A pressure fluctuation rate to an initial depressurization value (-20 kPa) is obtained. If the pressure fluctuation rate exceeds a preset allowable value (10%), it determines that there is a leakage. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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