| 摘要 |
PURPOSE:To set an air ratio to a low value over a wide combustion range and to improve air-resisting performance, by preventing the occurrence of an uneven air ratio at a low combustion range. CONSTITUTION:A device comprises a differential pressure detecting means 9 for detecting a difference between a pressure produced between a gas amount regulating means 2 and a variable gas throttle 3 and a pressure generated between a blower 5 for feeding the air for combustion and a fixed air throttle 6, and an air amount regulating means 10 for controlling the blower 5. The device is further provided with an electric controller part 13 which controls the variable gas throttle 3 and the gas amount regulating means 2 so that a throttle opening can be switched to the increased or decreased size when a combustion amount attains a previously set value, whereby a gas amount and an air amount are proportionally variably controlled over an entire combustion variable range, and in a range in which a combustion amount is below a previously specified set value, the throttle opening of the variable throttle 3 is switched to the reduced size, and control is effected in an increasing air ratio. This enables modification of a state in which an air ratio is sharply decreased especially in a low combustion range due to control error of a differential pressure detecting means, and permits improvement of air-resisting performance of combustion devices. |
