GB1042377A - Improvements in or relating to the manufacture of a glass strip - Google Patents

Abstract

In a process for forming a glass strip continuously drawn under its own weight through a slot in the bottom of a melting tank containing molten glass, the glass strip is, by the exertion of a traction effect on the strip where it cannot be damaged by the traction means, directed laterally, without contacting any solid elements, through a natural curve on to the surface of a bath having a density higher than that of the glass, the temperature of the bath decreasing in the direction of movement of the strip floating thereon. The glass strip 7 (Figs. 1 and 3, not shown), issues through a slot 4 and may pass through a drawing chamber 13 before entering the tank 9 containing the bath of molten liquid 10 which is denser than the glass, e.g. of tin, tin alloy, silver or mineral salts, the level of the molten liquid 10 being disposed below the slot 4. The strip passes through tank 9 along the surface of liquid 10 and is progressively cooled by controlling the thermal gradient along the length of the tank 9, and is then drawn into a lehr by traction rollers 8. The chamber 13 may be completely sealed from the atmosphere and may be placed between the slot 4 and tank 9 and may contain temperature control means. A controlled atmosphere of an inert gas, such as nitrogen, is maintained within the tank 9. Reference has been directed by the Comptroller to Specifications 769,692 and 937,738.