METHOD FOR MANUFACTURING MULTILAYER GLASS MATERIALS

1,217,956. Multilayer glass manufacture. ZAVOD AVTOSTEKLO. 22 Jan., 1968, No. 3317/68. Heading C1M. In a method of manufacturing a multilayer glass or glass-ceramic material having a porous layer a continuous ribbon of glass 2, formed between rollers 1, is passed whilst still plastic through a unit 3 wherein the ribbon is shaped into the form of a trough, powdered glass 12 containing a foaming agent is then fed into the trough-shaped ribbon and the whole passed through a heating lehr wherein the powdered glass is heated to form a porous layer fused to the trough-shaped ribbon. A member 13 ensures an even distribution of the powdered glass over the bottom of the trough, and in a part of the lehr, below the softening temperature of the porous glass, there is located a roller 14 which spreads and compacts the foamed glass layer to fill the space within the trough. Water-cooled transfer rolls 15 of heat-resisting steel are situated at the entrance to the lehr. If it is desired to have a glass-ceramic trough, the controlled devitrification occurs in the lehr with the foaming step. Reference has been directed by the Comptroller to Specification 1,112,083.