| 摘要 |
PURPOSE:To ensure the safety during the abnormality of a blower and in suction and exhaust system and at the same time enable to control the amount of combustion stably over a wide range without complicating the constitution of apparatus by a method wherein the shut-off function of a gas flow regulating means is utilized so that gas is released by means of the output of an first voltage comparator and shut-off by means of the output of an second voltage comparator. CONSTITUTION:The output of a differential pressure signal detection circuit 16 is connected to the non-inverted input of a voltage comparator A22 and to the inverted input of a voltage comparator B 23. Further, a positive set voltage e1 is connected to the inverted input of the voltage comparator A22 and a negative set voltage e2 is connected to the non-inverted input of the voltage comparator B23. Furthermore, an AND signal of the outputs of the voltage comparator A22 and of a voltage comparator C24 is applied to the S input and an OR signal of the output of the voltage comparator B23 and of the inverted signal of the output of the voltage comparator C24 is applied to the R input of a R-S flip-flop 25, while the output Q of the flip-flop 25 drives a solenoid valve 4 through a buffer 29. |
