To shorten the total processing time and reduce partial wear of a furnace wall by measuring the furnace wall temp. around each electrode, and controlling individually the input powers to the electrodes so that the measurements lie within the tolerable range.
A furnace body 11 is structured so that thermocouples 31-33 are embedded in a fireproof material 13 around the electrodes 21-33. The thermocouples 31-33 are connected with a computational control device 51 through respective thermometers 41-43. By these thermometers 41-43 the furnace wall temps. around the electrodes 21-33 are directly measured by the thermocouples 31-33, and the acquired measurements are fed to the computational control device 51, where they are compared with the preset values and subjected to a computational processing. For example, the electrodes 21-33 are elevated and lowered through an electrode device 61 in conformity to the command signals given from the control device 51 in accordance with the obtained difference between the measurements and set values, and the input powers to the electrodes 21-33 are controlled individually.
KAMESHIMA TAKATOSHI
KITABAYASHI SHOJI
