Importance

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Abstract

.[.Prior art high temperature electric furnaces of the type using two or more, usually three, primary electrodes positioned around an electrically conducting central outlet brought the electrodes in through a side or bottom wall of the furnace at points below the melt line causing many problems. The present invention provides a primary electrode arrangement for such melting furnaces wherein the primary electrodes do not pass through the wall or bottom of the furnace below the melt line, but instead enter the furnace over the top of the melt line and then protrude through the top surface of the melt. The primary electrodes of the present invention are provided with means for preventing wear and deterioration at the interface between the top surface of the melt and the unmelted batch and/or the oxidizing air atmosphere surrounding the top of the furnace. The improved furnace of the present invention does not require the use of a purging neutral or reducing atmosphere to protect the primary electrodes..]. .Iadd.Rapid wear and deterioration of refractory metals forming primary electrodes which are disposed in a high temperature melting furnace are obviated by utilizing a plurality of fluid coolers. One of the coolers may be disposed about the periphery of each primary electrode such that it is located at the melt line of molten material filling the furnace. A second cooler may be provided in the interior of each primary electrode at least for the exposed portion of each primary electrode at and above the melt line. .Iaddend.

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First Claim