| 摘要 |
PURPOSE:To make it possible to inform of the return operation of a self-sustained solenid valve of manual control type, by disposing an indicator which is turned on for a predetermined time when a returning signal is delivered to the above-mentioned valve, in a control circuit which issues a shut-off signal to the solenoid valve in accordance with a signal from a gas flow sensor. CONSTITUTION:A control circuit 2 in a gas shut-off device converts the turn-on and -off of a reed switch in a flow sensor 1 into high and low voltage signals by means of a resistor 2A. A micro-computer 2B receives these signals to process them in a predetermined way. When the shut-off condition of the gas shut- off device is satisfied, the micro-computer 2B issues a shut-off signal to energize a transistor 2C, and therefore, electrical current runs through a solenoid valve 3C to shut off a gas passage. Further, when the valve 3 is again opened by manual return operation, a reed switch 4C in a return detector circuit 4 is turned on. In this case, if a return signal is issued from the return detector circuit 4, the micro-computer 2B receives this signal, energizes a light emitting diode 2D for a predetermined time. |
