| 摘要 |
PURPOSE:To automate ignition, as well as to keep safety, by adding a function of automatic igniting operation which repeats ignition tries as many times as is preset by a counter circuit at the time when igniting operation is failed, to a combustion controlling device. CONSTITUTION:When an igniting operation is failed, a timer up signal is fed into the terminal 2 of an one shot multivibrator circuit 9 from a safety timr circuit 6 at the moment when a timer in the circuit 6 is up and the voltage in it is changed into H- level. Then the H-level signals from the output terminal 3 of the circuit 9 are fed into a reset circuit 10 to actuate it, for a specified time being set by a constant value at the time of C9 and R9. The reset circuit 10 resets both prepurge timer circuit 5 and safety timer circuit 6, and at the same time, it feeds a rise signal generated at the moment when the voltage in the circuit 10 is changed from L to H into the clock input terminal 14 of a counter circuit 11. The voltage in the circuit 11 is changed by the rise signal fed from the reset circuit 10. An igniting operation is tried again, after the prepurge timer circuit 5 is reset to the initial state by the reset circuit 10. When the count set in the counter circuit 11 is up, SCR in a safety switch circuit 4 is actuated, and an abnormal state is alarmed by an alarm buzzer B, as well as to stop the igniting operation by a diode D4 in the safety switch circuit 4. |
