| 摘要 |
PURPOSE:To keep the excess air ratio of primary air within good combustion range by a method wherein the rotational frequency of a blower to supply primary air to an entire combustion by primary air type burner is controlled in response to the output of a heat-sensitive element to detect the flame temperature of the burner. CONSTITUTION:A heat-sensitive element 13 such as thermocouple or the like is provided fronting on an entire combustion by primary air type burner 2 in order to control a blower 4 by changing its rotational frequency in response to the output of the heat- sensitive element 13. Concretely, a rotational frequency command circuit 14 to generate a rotational frequency command signal in response to the output of the heat-sensitive element 13, a rotational frequency detection circuit 16 to generate a signal responding to the actual rotational frequency of the blower 4 based upon the output of a pick-up coil for the detection of the rotation of the blower 4 and a differential amplification circuit 17, to which the signals from both the circuits 14 and 16 are inputted, are provided so as to put the transistor 18 into actuation in order to control the rotation of the driving motor 4a of the blower 4 based upon the output of the differential amplification circuit 17 in such a manner that the rotational frequency of the blower 4 is changed so as to bring the deviation between the signals from both the circuits 14 and 16 to zero. |
