GB786253A - Improved method of thermally conditioning glass which is to be drawn into sheets - Google Patents

Abstract

786,253. Drawing glass. COMPAGNIES, REUNIES DES GLACES ET VERRES SPECIAUX DU NORD DE LA FRANCE. March 23, 1956 [March 28, 1955], No. 9103/56. Class 56. Glass passing from the firing zone 1 of a furnace to a shallow draw bath 3, Fig. 1, or a deep draw bath 19, Fig. 3, traverses a shallow covered canal 2 wherein it is thermally conditioned. The thermal conditioning consists in severely reducing the heat losses from the upper and side surfaces of the glass in the canal (as by selecting suitable materials for making and lagging the roof and sides of the canal), and simultaneously increasing the heat losses from the bottom of the glass. The heat losses from the bottom are increased preferably by substantially reducing the thickness of the bottom of the canal and by providing air coolers, cooling jackets or the like. Alternatively the bottom may be made of normal thickness but of material which has a comparatively high thermal conductivity, e.g., fused mullite or mullite and zirconium or corundum; the loss may be augmented by blowing air against the bottom. In Fig. 1, the bottom of the canal is formed of thin blocks, 6a carried by beams 31a, 31, 31b, with adjustably mounted watercirculating coolers 10. In Fig. 3 the watercooled bottom of the canal is supported by an arch forming the roof of a return canal 20 for the glass.