| 摘要 |
PURPOSE:To prevent fluid leaks by detecting fluid that leaks from the high pressure side conduit to the low pressure side conduit through valve seat at the time of the valve actuation, and if the fluid leakage exceeds the specified value, the valve is actuated to cause a bellows to expand to press the valve plate against the valve seat. CONSTITUTION:The valve apparatus can be closed airtight at the high and low pressure side conduits 1, 4 by actuating a valve plate 10 to the closed position in a valve body 2 which is disposed between the high and low pressure side conduits 1, 4, and causing a bellows 17 to expand toward the valve plate 10 to press a valve seat 11 of the bellows 17 side against the valve plate 10. In such a construction, the amount of He leakage from the high pressure side conduit 1 to the low pressure side conduit 4 through the valve seat 11 is detected at the time of the valve closure actuation by a He leak detector 26. The detected signal X is supplied to a reducing valve 22, and if the amount of He leakage exceeds the specified value, the reducing valve 22 is actuated to increase the pressure in the bellows 17. By this constitution, fluid leaks from the high pressure side conduit 1 to the low pressure side conduit 4 is prevented. |
