| 摘要 |
PURPOSE:To make it possible to maintain stable combustion conditions by a method wherein at least either the amount of air supplied or the amount of fuel supplied is controlled by the minimum value retrieval output signal of flame current which is detected with a flame rod. CONSTITUTION:The flame current If of a burner 1 is transmitted with a flame rod 6 to a flame current detection part 8, permitting a minimum value retrieval part 9 to output signals to an air-fuel ratio control part 10 so as to minimize the output signal. An air flow rate control part 11 drives a fan 4 so as to feed air at the predetermined flow rate. A minimum value retrieval part 9 stores the flame current If as the minimum value Ifmin and outputs a signal to the air-fuel ratio control part 10 to request the increase of the air flow rate by DELTAQA. The resultant flame current If is compared with the minimum value Ifmin. If the resultant If is smaller than Ifmin, the resultant If is newly stored as the minimum value Ifmin and the minimum value retrieval part 9 outputs a signal to the air-fuel ratio control part 10 to request the increase of the air flow rate further by DELTAQA. On the contrary, if the resultant If is larger than Ifmin, the minimum value retrieval part 9 outputs a signal to the air-fuel ratio control part 10 to request the decrease of the air flow rate by DELTAQA in order to maintain the combustion in which the flame current If is minimum. |
