| 摘要 |
PURPOSE:To ensure the burner ignition by preventing troubles in the flame transfer and ignition by reducing the supply of fuel and air at the time of ignition so that the air/fuel ratio may be greater than one (1). CONSTITUTION:A burning control circuit 15 outputs control signals to fan 11, gas pressure proportioning valve 6, gas shutoff valve 6a and ignition circuit 7A, and receives the flame detection signal from a flame detection circuit 10. The delivery opening 11A of the fan 11 has a shutter so as to regulate the opening area. At the time of ignition, air and gas fuel is supplied in an amount smaller than in the normal operating condition, and the air/fuel ratio is also made greater than one (1). At this time, the speed of combustion air flowing through burners 1-5 becomes slower, and so, the gas fuel ejecting out of the burners drift sideways, resulting in the sure flame transfer. When the flame is detected by the flame sensor 8, the burning control circuit 15 operates to supply air and gas fuel for the normal burning. |
