GB1331635A - Method for the production of glass - Google Patents

Abstract

1331635 Producing ribbon glass TRANSGLAS PATENT-UND LIZENZWERTUNGS AG 1 Oct 1970 [3 Oct 1969 17 June 1970] 46742/70 Heading C1M In the production of ribbon glass and while the glass has a viscosity of between 10<SP>3</SP> and 10<SP>10</SP> poises, the glass is stretched by an amount corresponding to at least 30%, in at least one glass stretching zone, and is subjected to at least natural cooling in said zone. This may be achieved by allowing glass to flow over a lip 3 of a glass-melting furnace and then to flow vertically in a compartment 11 so that the glass ribbon is stretched under its own weight. The temperature of the glass flowing over the lip is sensed by thermocouples and controlled by electrical heating elements 13 to ensure that its viscosity is about 10<SP>3</SP> poise. Cooling devices 16, 17 provide additional cooling of the ribbon as it leaves the compartment 11. Alternatively the stretching may be carried out by conveying a glass ribbon from a furnace to a stretching zone defined by two pairs of rollers 20, 21 and 26, 27 the second pair rotating at a higher velocity than the first. A third pair of rollers 27, 28 may also be used thus defining a second stretching zone. The thermal losses from the glass are controlled so that the temperature fall in the first zone is 300‹ C. and in the second zone 150‹ C. Wire glass may be produced by embedding metal wires in the glass at the beginning of the production path. A glass containing in percentage by weight SiO 2 69; alkali metal oxide 14; alkaline earth metal oxide 12; trivalent element oxide 1À4b, B2O 3 1À94, the remainder being TiO 2 and SO 3 is disclosed.