PREHEATING OF MATERIAL UTILIZING EXHAUST GAS

PURPOSE:To retrieve the amount of retaining heat of exhaust gas effectively to permit the preheating of a backet, by a method wherein two sets or more of electric furnaces are arranged and when a part of them is in the condition of secondary preheating, the balance of the electric furnaces are put in melding or refining condition while the exhaust gas of the electric furnace is guided into the backet and the rotating number of a discharging fan is controlled based on a pressure at the inlet side of the backet. CONSTITUTION:Exhaust gas, generated in electric furnaces 3, 5, is collected into a collecting duct 10 through branch ducts 9a, 9b and is sent into a backet 2. An inlet side valve 11 is provided on the half way of the collecting duct 10 while the pressure of exhaust gas before the inlet side valve 11 is detected by a pressure detector 12. The exhaust gas preheats a material in the backet 2, thereafter, is sent into a fan 14 through an exhaust duct 13. The rotating number of the exhaust fan 14 is controlled by a rotating number controller 15 while the rotating number controller 15 controls the rotating number of the exhaust fan 14 so that the pressure of the exhaust gas at the inlet side of the backet becomes a set value. According to this method, the total amount of the exhaust gas may be utilized for the preheating of the material whereby the heat of the exhaust gas may be consumed efficiently.