| 摘要 |
PROBLEM TO BE SOLVED: To stably exhaust a burnt gas from a boiler by sending a gas to an induced draft fan so as to compensate a reduced amount in association with a reduction in a flow rate of the gas passing the ventilator. SOLUTION: A blast furnace gas from a blast furnace 24 and an air from a forced ventilator 11 are supplied to a boiler 10. A controller 40 receives flow rate data from a gas flow detector 23, and confirms a flow rate of a burnt gas passing an exhaust duct 17. When the flow rate of the gas is reduced, the controller 40 outputs an open command to a damper 21 of a gas supply unit 19 to open the damper 2. Thus, an atmospheric air is supplied to a suction side of an induced draft fan 13 through a suction duct 20 and an exhaust duct 14. Then, the controller 40 opens the damper 21 in the degree of supplying the air of an amount flowing to the duct 20 for compensating the reduced amount of the gas passing the fan 13. Thus, the rotation of an impeller of the ventilator 13 is stabilized and the gas from the boiler 10 can be stably exhausted.
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