| 摘要 |
PURPOSE:For stabilizing the operation of air heating furnaces, to make control so that the preheating temperature of the air for combustion may be kept at a fixed value. CONSTITUTION:The decrease of the temperature of the waste gas from an air heating furnace 2, i.e. the preheating temperature of the air for combustion, is detected by a temperature detector 19, and thus-obtained detection signal is fed to a main control signal 16 and compared with the setting value thereof from a setting means 17. Thus-obtained indication signal is fed to a driving means 14, and an auxiliary preheater 13 actuates to raise the temperature of waste gas. Said preheater 13 stops when the preheating temperature of the air for combustion has risen to a proper value along with the rise of the temperature of said waste gas. When the preheating temperature of the air for combustion has risen quickly due to the firing for example of said air preheater 6, the indication signal from said setting means 17 is fed to said driving means 15, a flow adjusting valve 4 actuates properly to open a bypass circuit 5, and diluted air flows in to lower preheating temperature. Said valve 4 is closed when the preheating temperature of the air for combustion has come down to a proper value. |
