JPS5747888A - Method for controlling furnace voltage during scooping-out of molten metal - Google Patents

Abstract

PURPOSE: To perform titled controlling with high accuracy and return furnace voltage to the value before starting after the end of scooping-out of molten metal by outputting or stopping a pole distance reduction signal properly according to the smoothing value of the furnace voltage and making the smoothing value after the end of scooping-out of molten metal equal to an initial value.

CONSTITUTION: A (smoothig value) schedule of smoothing the furnace voltage per se or furnace resistance value through detecting the same at fixed time intervals over the molten metal scooping-out period in an Al electrolytic furnace is incorporated. According to this schedule, the smoothing value is detected and when this rises more than an upper limit value, a pole distance reduction signal is generatd over a fixed time. When it lowers below a lower limit value while said signal is being received, the outputting of said signal is stopped, by which the accuracy of furnace voltage controlling is improved. Further, the operation of storing the smoothing value at the starting of scooping-out of the molten metal as an initial value and making the smoothing value after the end of scooping-out of said metal equal to the initial value is performed, whereby the furnace is operated on the same furnace voltage as that before the scooping-out even after the scooping-out.

COPYRIGHT: (C)1982,JPO&Japio