| 摘要 |
PURPOSE:To improve the stability and to reduce the cost by causing a high voltage charged in a condenser to solenoid valve and holding the valve in an open position by flowing a low current to the solenoid valve through a resistor thereafter. CONSTITUTION:The voltage which is charged to a condenser 5 from a commercial power source voltage section through a rectifier 3 and a resistor 4 is allowed to flow through a solenoid valve 6 when a transistor 7 is turned on. Therefore, the solenoid valve 6 is instantly applied with a voltage to be opened to allow the gas to flow to the burner, which is ignited by a spark. Thereafter, a low voltage is applied to the solenoid valve 6 through the resistor 4 to hold the solenoid in an open position for sustained burning. The burning is monitored by a flame rod 14, and if the flame is extinguished due to a wind etc., a microcomputer detects it and the output (a) is stopped. Then, the transistor 7 is turned off to block the circuit, and the solenoid valve 6 is closed to prevent the raw fuel gas from leaking. Therefore, fire hazard, gas explosion or gas poisoning can be prevented. |
