PURPOSE: To reduce the consumption of a furnace material and to finish the base of a high-viscosity glass by rapidly melting the high-viscosity glass close to the throat and the bottom wall of a melting tank.
CONSTITUTION: At least a couple of electrodes 4 and 4' are vertically inserted away from the lower part of the bottom wall of a throat 2, the inner wall of the throat is covered with a high-viscosity glass material layer, and a low- viscosity glass material layer 7 is laminated on the high-viscosity material layer. As the melting furnace is heated, the low-viscosity glass material layer is melted, and the high-viscosity glass material layer 8 is melted by the AC voltage impressed between the electrodes. A cullet is then successively charged from the molten layer side to finish the base.
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