| 摘要 |
PURPOSE:To restrain dewing on a heat exchanger at the time of a low input while making thermal efficiency as high as possible, by controlling the opening of a damper so that the quantity of primary air supplied is proportional to that of a gaseous fuel whereas the quantity of secondary air supplied is inversely proportional to that of the gaseous fuel. CONSTITUTION:A sensor 17 is provided to detect the quantity of gaseous fuel supplied to a burner 2, a slide-type damper 18 is provided to antinomically regulate the quantity of air supplied into a primary air supplying passage 11 and that into a secondary air supplying passage 12, and a program-type controller 20 is provided to automatically operate a driver 19 for the damper 18 on the basis of data from the sensor 17. Namely, the quantity of air supplied into the primary air supplying passage 11 is regulated proportional to the quantity of a gaseous fuel supplied, so that stable combustion free of blow-off at the burner 2 or lifting of a flame is maintained. In addition, the quantity of air supplied into the secondary air supplying passage 12 is regulated inversely proportionally to the quantity of the gaseous fuel supplied, and excess air ratio is increased as input is lowered, so that generation of drain is restrained while making thermal efficiency as high as possible. |
