Application of electrical heating in forehearth channels

Abstract

Electrical heating of forehearth channels can be either indirect with radiant heating elements installed above the glass surface, or direct utilizing immersed electrodes. Two types of heating elements are used, made of either silicon carbide or molybdenum disilicide. Electrodes are normally made of molybdenum, but tin oxide is also used, and platinum alloy may be required for some special applications. Direct electrical heating is also used in forehearths to supplement the traditional gas heating, and can provide a significant improvement in the thermal homogeneity of the glass at the end of the channel. Excellent results can also be obtained with full electrical heating. Whatever type of electrical heating is used, the relevant safety standards must be applied.