Manufacture of drawn sheet glass
AssigneeGlaverbel
InventorAdrianus Geppaard
Life of this patent
Estimating the term…
Abstract
Molten glass 1 flows continuously from a glass melting furnace 2 to a drawing tank 7 whence the glass is drawn as a continuous ribbon 10 from a slot 11 in a refractory device 12 such as a debiteuse partially immersed in the molten glass. The center of the slot 11 is spaced from each of upstream 6 and downstream 9 end walls of the drawing tank 7 by at least 550 mm. The debiteuse 12 is preferably spaced from those walls by at least 350 mm. This promotes and facilitates production of a high yield of glass of a high standard of thickness uniformity and of good planeity. These advantages are enhanced when the ribbon is passed over a bending roll 13 in a drawing chamber 8 above the drawing tank 7 and thence to a horizontal annealing lehr 14.
Claims26
A sheet glass manufacturing process comprising:
- supplying molten glass from a glass melting tank furnace, where the molten glass is produced, to a drawing tank having an upstream end wall at the end of the drawing tank directed toward the tank furnace and a downstream end wall at the end of the drawing tank directed away from the tank furnace;
- positioning a refractory device provided with an elongated slot having a longitudinal center line in the drawing tank so that the refractory device is partially immersed in molten glass in the drawing tank to a sufficient depth such that the top of the slot is below the level of the surface of the molten glass in the drawing tank for causing molten glass to be forced upwardly through and out of the slot by hydrostatic pressure, and the longitudinal center line is spaced from each end wall, the refractory device further having a rim extending around the periphery of the device, spaced laterally from the slot, and projecting upwardly from the level of the top of the slot to a height above the level of the surface of the molten glass in the drawing tank, to form a region surrounding the top of the slot which is free of molten glass;
- and drawing molten glass upwardly in the form of a continuous ribbon from glass which has been forced out of the slot and into a drawing chamber located above the drawing tank;
- wherein the tank is dimensioned and the refractory device is located such that the longitudinal center line of the elongated slot is spaced by a distance of at least 550 mm from each end wall of the drawing tank and, during said step of drawing, a free glass surface is maintained in the drawing tank between the refractory device and each of the end walls of the tank, and the tank is so dimensioned that the glass surface to each side of the refractory device is at least 350 mm long measured in a direction normal to the plane of the upwardly drawn ribbon.
A sheet glass manufacturing plant comprising:
- a glass melting tank furnace for producing molten glass;
- a drawing tank connected to the furnace to receive a continuous supply of molten glass therefrom, said drawing tank having an upstream end wall at the end of said drawing tank directed toward said furnace and a downstream end wall at the end of said drawing tank remote from said furnace;
- a drawing chamber disposed above said drawing tank;
- a refractory device provided with an elongated slot having a longitudinal center line, said device being disposed in said drawing tank to be partially immersed in molten glass in said tank to a sufficient depth such that the top of said slot is below the level of the surface of molten glass in said drawing tank and so that molten glass is forced upwardly through said slot by hydrostatic pressure, said refractory device further having a rim extending around the periphery of said device, spaced laterally from said slot, and projecting upwardly from the level of the top of said slot to a height which will be above the level of the surface of the molten glass in said drawing tank when said refractory device is partially immersed in the molten glass, to form a region surrounding the top of the slot which is free of molten glass when molten glass is being drawn upwardly in the form of a continuous ribbon;
- and means from drawing molten glass upwardly in the form of a continuous ribbon from said slot into said drawing chamber;
- wherein said drawing tank is dimensioned and said refractory device is located such that the longitudinal center line of said slot is spaced by a distance of at least 550 mm from each said end wall of said drawing tank, and said refractory device is spaced from each of said upstream and downstream end walls by a distance of at least 350 mm.
Dependencies are inferred from the claim text.