| 摘要 |
PROBLEM TO BE SOLVED: To make an air preheating chamber unnecessary and contrive the remarkable simplification as well as compacting of a device by a method wherein the concentration of oxygen and a ventilating air temperature are detected by sensors and when the detecting values thereof are deviated from set values, outdoor air is introduced into a combustion hot-air bypass duct through the operation of a forced ventilating fan and the opening of a damper. SOLUTION: Combustion gas is discharged into atmosphere through a gas cooling chamber and a chimney as exhaust gas. However, a part of exhaust gas, which is guided to the fore side of the gas cooling chamber 4, is guided into a combustion hot-air bypass duct (DCT) 6, communicating with the gas cooling chamber 4, by a forced ventilating fan 11. The amount of dissolved oxygen in the exhaust gas, guided into the duct 6, is detected by an oxygen concentration measuring instrument 9. When the detected value is not arrived at a set value, the damper 8 is opened to introduce outdoor air and obtain a predetermined oxygen concentration. The temperature of the exhaust gas is detected by a ventilating air temperature measuring instrument 10. When the detecting value exceeds a set value, a part of air is introduced to obtain a predetermined exhaust gas temperature. |
