Electric melt furnace-electrodes inclined toward each other to vary the firing path during steady state operation and to create hot spots after heat loss or during start-up

摘要

Where electrodes mounted in an electric melt furnace are inclined toward each other, the current distribution between the electrodes is the least in density in the region between the electrodes where the displacement is the widest, and increases in the region between the electrodes at the tips where the displacement is the narrowest. The maximum current density can be focused in a particular area, preferably toward the upper regions of the electric melt furnace where the batch is being melted to its liquid state. Additionally, the high density current is removed from the walls, and wear and tear on the refractory is thereby reduced. An alternate embodiment is to group a number of inclined electrodes and to excite each of the separate electrodes within the group from a separate phase of the power supply. This produces current paths between each of the inclined electrodes in the group, and is used after the furnace is cooled down and hot spots must be created to start the furnace up again. In this way, even though the melted material has cooled and where the melting material has a negative resistance coefficient, the resistance has increased, the distance between the inclined electrodes is still small enough to effect a resistance path therebetween and create a current to heat up the material again. Once the operating temperature of the furnace has been regained, the electrodes may be switched so that all the inclined electrodes within the group are energized in parallel from the same phase of the power supply, and operated with another remote group of electrodes also connected in parallel to the same energy source.