| 摘要 |
PURPOSE:To detect even little amout of gas leakage regardless of the kind of gas by generating an alarm when a pressure drop after the confinement of pressurized gas has a speed faster than a set value. CONSTITUTION:When an outlet-side solenoid valve 1b is closed and an intake- side solenoid valve 1a is opened, the pressure in a gas flow passage 3 rises and attains to specific gas leakage check pressure V1 and its output is detected by a pressure transducer 4 and supplied to a holding circuit 5 and a subtracting circuit 6. Then, the valve 1a is closed and both ends of the gas flow passage 3 are sealed. At the same time, a control part 8 sends its output to the holding circuit 5 to start a timer 12. When the pressure in the flow passage 3 drops owing to gas leakage, the output of the subtracting circuit 6 increases gradually and when it exceeds specific differential pressure, the output of a comparing circuit 10 excites an AND circuit 7 to put an alarm output part 9, annunciating the gas leakage. |
