VARIABLE CAPACITY VERTICAL RAPID MELTING FURNACE

PROBLEM TO BE SOLVED: To enable the range of hot water supply capacity to be twice to three times as large as the fundamental capacity by supplying a specific oxygen reinforcing amount from an oxygen tank in the supply air to the tuyere of a furnace body into an air supply tube, variably setting oxygen concentration, and supplying it as the supply air from a wind box to the tuyere. SOLUTION: When the melting capacity, coke ratio and output hot water temperature are input to a digital indication regulator 24, a programmable controller 18 calculates the supply air amount responsive to the melting capacity of a molten metal. The supply air amount to the tuyere 2 is measured via an air flow measuring orifice 17 connected with a differential pressure oscillator 16 based on the calculated result, an air flow regulating valve 15 is controlled, and the air is supplied from an air supply tube 14 to a wind box 3. Simultaneously, the enriching amount of the pure oxygen to be enriched is calculated, the pure oxygen of a range of 1 to 20% is measured by an oxygen flow measuring orifice 22 connected with a differential pressure oscillator 21 from an oxygen tank 19, supplied from an oxygen enriching supply tube 23 to the tube 14 via an oxygen flow regulating valve 20, and supplied from the box 3 as supply air to the tuyere 2.