Square glass furnace with sidewall electrodes

摘要

An electric furnace having four equal length and height sidewalls at right angles to each other, and a bottom with an outlet trough under the center of one of said sidewalls. All of the rod electrodes for this furnace project horizontally inwardly from corner areas of the sidewalls usually perpendicularly to each sidewall equally spaced from the corner, but they may be angled less than about 20 DEG toward the corner. For shallow furnaces having relatively low sidewalls only one or two electrodes at each corner area are required, all of which electrodes are located in the same horizontal plane. However, for deeper furnaces, two or more parallel horizontal planes of electrodes are provided which planes are equally vertically spaced less than the distance of the top electrode to the top of the furnace and the bottom electrode to the bottom of the furnace. Each of the electrodes are mounted in insulation blocks which extend inwardly from the inner surface of the furnace and surround each electrode. The current supply to this furnace is a two-phased current in which the phases are 90 DEG apart and may be adapted from a three-phase current by a Scott transformer connection. All of the electrodes at two opposite corner areas are connected to one of the two phases, while all of the electrodes at the other two opposite corner areas of the furnace are connected to the other phase. The outside of the furnace is preferably provided with an insulation layer except on those portions of the wall adjacent the electrodes away from each corner, which portions are hottest and preferably cooled by an air blast.