| 摘要 |
PURPOSE:To cut off a vlave opening circuit at a proper time at the time of begining by opening a switch for the valve opening circuit closed at the begining by an electronic control circuit operated when a terminal electromotive force of a thermocouple has become to be high enough. CONSTITUTION:When a valve for a pilot-burner is opened and an electric source switch 01 is closed, a solenoid 30 is energized and a switch 31 is closed, thereafter, sub-switch 32 is opened a little bit later. By the closing operation of the switch 31, a valve opening circuit B is closed and an electromagnetic holding valve 2 is opened, thereby, gas is supplied to the pilot-burner. At the same time, an electric igniter 4 provided in parallel is operated and the pilot-burner is ignited. When an electromotive force is generated from a thermocouple heated by the pilot burner and the output thereof arrives at a necessary value, a variation detector 5 and a converter 6 detect it and the valve opening circuit B is opened while a security circuit is closed, thereby, the electromagnetic holding valve is held in open. |
