| 摘要 |
PURPOSE:To maintain intrafurnace temperatures above an acid dew point for low-temperature baking and prevent shortening of the life of furnaces or equipment by keeping the temperature of a hot blast to coated steel plate at a prearranged temperature at the time of low-temperature operation, and controlling baking temperatures through variation of the air flow. CONSTITUTION:At the time of high-temperature operation, a hot blast at sufficient temperatures to cancel a deflection of baking temperature is blown by controlling the burner combustion value of air heaters 5-7. Thus coated steel plate W is baked by the hot blast ejected from air ducts 3a-3c. In the meantime, during low-temperature operation, the temperature of a hot blast from the air heaters 5-7 is maintained above the acid dew point, and for instance, if a detected baking temperature is higher than a target baking temperature, a present exhaust gas flow is decreased by a value corresponding to a baking temperature deflection by controlling an exhaust gas fan 13. Consequently an air feed amount to the air heaters 5-7 is reduced in accordance with this exhaust gas flow decrease. As a result, a total calorific value to steel plate W decreases, which in turn reduces the baking temperature.
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