GB442702A - Improvements in or relating to process and apparatus for making plate glass - Google Patents

Abstract

442,702. Glass manufacture. STEVENS, A. H., 5, Quality Court, Chancery Lane, London.-(Pittsburgh Plate Glass Co. ; 200, Grant Building, Pittsburg, U.S.A.) March 23, 1935, No. 9156. [Class 56] A process for making plate glass consists in continuously supplying a layer of molten glass of substantially uniform thickness over a supply or feed roll, conducting thesheetthus formed into the pass between a pair of sizing - rollers and allowing the sheet to sag and stretch between the feed and sizing rolls, and regulating the speeds of the rollers in such a way that a bulb of plastic glass is constantly maintained at the entrance to the pass between the sizing rolls. The glass flows from a tank furnace through a cooling chamber 2, Fig. 1, and a draw pot 3 whence it is discharged through a slot 4 in the form of a sheet 5, Fig. 7. This sheet is carried over a feed roll 6 and between sizing rolls 7, 8 whence the finished sheet passes over runway rolls 9 into a leer 10. The feed roll 6 is driven at a lower speed than the sizing rolls, so that the sheet 5 stretches and becomes thinner. A bulb or roll 88 of glass is also formed and maintained at the entrance to the pass between the sizing rolls, so that the pass is always completely filled with glass from end to end. The draw pot 3 is mounted above heating flues 11, and the cover of the pot consists of three sections with two intervening walls each of which is independently adjustable in a vertical direction in order to bring the glass in the pot to a uniform temperature across its width. The front wall of the pot comprises an upper member 25 suspended from an overhead crane, and a lower or lip member 28 which is supported on screwed rods 31 to enable it to be adjusted vertically, or to be tilted from side to side to ensure an even flow of glass over the lip. The feed roll 6 is watercooled, and means are provided for adjusting it vertically or for tilting it slightly. The sizing rolls 7, 8 are cooled by circulating air through them. The lip member 28 is preferably provided with a sheath 68 of metal which is resistant to the action of hot glass, and means are provided for tensioning the metal both transversely and longitudinally in order to keep it smooth. Pipes 83 and watercoolers 84, 85 are employed to regulate the temperature of the glass. The pipes 83 are perforated and direct air jets in to the glass, and similar pipes 86 blow air on to the rolls 7, 8. In a modified construction, the feed roll 6 is replaced by a series of rolls.