METHOD AND APPARATUS FOR EQUALIZING THE WALL LINING WEAR IN THREE PHASE ALTERNATING CURRENT ELECTRIC ARC FURNACES

摘要

1525333 Arc furnace S E STENKVIST 21 Jan 1976 [27 Jan 1975] 02274/76 Heading H5H Wear on the furnace lining of a three-phase arc furnace is equalized by utilizing an electromagnet 8 below the furnace lining 4 to produce a symmetrical magnetic field intersecting the arcs 9 of the electrodes 1, 2, 3, the polarity of the magnet 8 being maintained unchanged for a period substantially exceeding the time period of one complete cycle of the electrode supply current. The field of coil 8 interacts with the rotating magnetic field produced by the arc current so that instead of a single hot spot in the furnace lining adjacent each electrode, two hot spots 12 displaced by 45 degrees relative to the conventional single hot spot, are produced per electrode. By energizing the coil 8 intermittently or with a low frequency A.C. (less than the electrode supply frequency) the wear may be evened out on the lining between each pair of hot spots. The coil may be suspended from the furnace bottom by three magnetic yokes and it may have a core. The furnace bottom must be non- magnetic adjacent the coil when the coil 8 is beneath the furnace shell 6 but should the coil be mounted between the shell 6 and the lining 4 the bottom may be magnetic. The coil 8 may be a pancake coil provided with radial yokes. Separate coils may be placed around the suspending magnetic yokes.