| 摘要 |
PURPOSE:To prevent the gas burning chamber from explosion and contrive to stabilize rapidly the flame of a gas burner by a method wherein the opening degree of a proportional control valve is enlarged for fixed time after the detection of a gas flame. CONSTITUTION:At the detection of a flame by a flame detecting circuit, a timer circuit is operated, a convection blower 303 is disenergized for fixed time, also the output side of a temperature sensing element 502 for inputting to the first operating amplifier 503 is earthed for fixed time by the operation of the second timer part 494 and a transistor 495. Thereby, the voltage difference inputted to the first operating amplifier 503 is increased without regard to the output of the temperature sensing element 502, the first operating amlifier 503 generates the large output, the opening degree of the proportional control valve 205 is gradually enlarged via a delay circuit 507. By said operation, the flame can be rapidly stabilized by the heating due to the increasing of the flame of a gas burner 104. By the enlargement of the opening degree of the proportional control valve 205, the gas quantity required for the ignition can be secured, accordingly, the burning chamber can be prevented from explosion due to the gas supplying shortage. |
