| 摘要 |
PURPOSE:To enable to close all of gas cocks simultaneously when one of a plurality of gas-leakage detectors detects leakage of gas, by connecting means for driving the gas-leakage detectors consisting of a gas detector, detecting circuit, reset switch and driver in parallel to each other. CONSTITUTION:When gas is detected by a gas detector 4, its resistance is reduced and its output voltage VRL is increased. Resultantly, a detecting circuit 5 is set into operation and transistors Tr1-Tr3 are turned ON, so that an indicator 10 is lighted. Through energization of the transistor Tr3, a capacitor C1 begins to discharge and a PUT and a thyristor SCR are turned ON. Further, a normally de-energized reset switch 7 is turned ON and a driver 3 is set into operation. Thereupon, many other drivers 3 connected in parallel to each other are set into operation simultaneously to operate meny gas cock closing means 2 connected in parallel to respective drivers 3 and to thereby close all of the gas cocks for propane gas cylinders simultaneously. |
