| 摘要 |
PURPOSE:To enable the signal of open or close condition of a gas shut-off valve to be surely outputted by generating pulses by means of the inverse electromotive force generated at the time of closing and opening of the gas shut-off valve, and delaying the shut-off output signal for a certain time from an actual shut-off by a memory circuit. CONSTITUTION:When a shut-off signal 6 of a gas shut-off valve 1 is inputted to the input terminal A of a gas shut-off indicator device, a signal 7 is outputted which is delayed in a delay circuit 2 for a certain time from the actual timing of shut-off, and a positive pulse 9 is generated by detecting an inverse electromotive voltage 8 generated in the gas shut-off valve 1 by a voltage detection circuit 3. Similarly, when the gas shut-off valve is restored, an inverse electromotive voltage 11 is generated, and the inverse electromotive voltage 11 is detected by a negative voltage detection circuit 3 to cause a positive pulse to be generated. Therefore, a memory circuit 4 continues to output a signal 10 from the moment of the inverse electromotive voltage generation at the time of shut-off to the moment of the restoration, and by means of an open-close condition indicator receiving the signal 10, the open-close condition of the gas shut-off valve can be identified. |
