| 摘要 |
PURPOSE:To prevent a raw gas from discharging by providing a circuit which flows reverse current to a safety valve system to close the safety valve. CONSTITUTION:The titled circuit is provided with a manually operating member 5 which is switchable to closing, opening and igniting. In a gas passage 2 communicating with a burner unit 1 are provided an electromagnetic safety valve and a cut-off valve 4 disposed in series with a safety valve 3. By manipulating the operating member 5 from a closing position to an igniting position via an opening position, the safety valve 5 and the cut-off valve 4 are depressed and opened and the burner unit 1 is ignited. By manipulating the operating member 5 from the igniting position to the opening position, depression of the safety valve is removed. The safety valve is kept in an open state by a discharge current of a condenser 13 and an electromotive force of a thermocouple 12 provided in the burner unit 1. Furthermore, by manipulating the operating member 5 from the opening position to the closing position, the cut-off valve 4 is closed and the burner unit 1 is extinguished. In this case, the titled circuit is provided with a circuit which flows a reverse current cancelling a current generated by an electromotive force of the thermocouple 12 to a solenoid 3a of the safety valve 3 in linkage with the closure of the cut-off valve 4, so as to close the safety valve 3. As a result, during a period in which the thermocouple is cooled and the safety valve is closed such a trouble that the raw gas is discharged, can be prevented. |
