| 摘要 |
PURPOSE:To enable a proper control over combustion and improve safety and reliability without being influenced by a turned-ON or a turned-OFF condition of suction by a method wherein a holding circuit for holding a detected condition when the sensor detects an operation of an energization fan at once is provided. CONSTITUTION:An air pressure switch 9 is turned on by a pneumatic pressure suctioned when a purging is performed in advance by a fan 2, a relay 23 is operated to close a contact point 23a and to form a self-holding circuit. Further, by closing of contact point 23b, a solenoid valve 5 is released by a driving circuit 24, fuel is supplied to a combustion part 4 and a pulse operated combustion is started by an ignition electrode 6a. Then, the operation of the fan 2 is stopped, the air pressure switch 9 repeats its turned-on or turned-off condition as the flap valve 3 is opened or closed, and a supplying of fuel under an operation of the solenoid valve 5 can be continued with a self-holding of the relay 23. When a fire sensor 10 detects a stopped operation or a misfire at the combustion part 4, a clear contact point 22 is released and then the self-holding circuit for the relay 23 is reset. |
