| 摘要 |
PURPOSE:To prevent any trouble due to the leakage of gaseous fuel by forcing the main valve into a closed state in a case when gas fuel leaks. CONSTITUTION:Prior to turning on a supply switch 16, if a cock is in a valve opened state, an opening and closure detecting switch S is in an interrupted state, and, accordingly, a self-holding circuit 16 does not assume a self-holding state, and a solenoid 3 remains as it is erased, thus an electromagnetic valve 2 being closed, and hence the flow-out of the gaseous fuel being prevented. In a case when the leakage of the gaseous fuel occurs while it is in use, and the concentration of the leaked gaseous fuel is relatively high, a gas leakage detector W2 becomes conductive. For this reason, a relay R2 is energized, a relay 21 becomes conductive, and the relay R3 is energized and self-held. Therefore, a relay switch r32 is cut off, and as a result, a relay R4 is de-energized and self-holding of the self-holding circuit 16 is released. Therefore, the solenoid 3 is de-energized, and the electromagnetic valve 2 becomes a opened state. |
