| 摘要 |
A glass melting furnace in which glass can be heated by sources below its upper surface, as electrically by Joule effect, and by means above its upper surface, as by fossil fuel firing or by heat reflectors. A cold top melting mode is employed in the charging region of the furnace while the glass discharge region maintains an exposed molten, upper surface on the glass. In a disclosed embodiment a high crown over the charging region enables cold top melting and refining to be accomplished by Joule effect while flues and burner ports in that region are closed. A low crown, which may be adjustable in its height above the glass line, is provided over the discharge region to increase heating at the exposed, molten upper surface of the glass by reflection. Heating in the discharge region can be augmented by above surface heaters distributed across the crown. A flue in the discharge region carries gases from that region. The degree of heat flow from the discharge region to the charging region is controlled by an adjustable heat barrier. One form of barrier is a transverse wall mounted between the regions and arranged for adjustable elevation above the glass line. The degree of refinement of the glass in the discharge region permits use of the surface throat in furnaces where Joule effect heating provides the preponderant source of heat.
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