Method and apparatus for vertically drawing a glass ribbon
AssigneeGlaverbel-Mecaniver
InventorEmile Plumat
Life of this patent
Estimating the term…
Abstract
In the manufacture of sheet glass by drawing a ribbon of glass upwardly from a molten glass bath via a meniscus located at the glass surface in the drawing zone, a pool of molten material is contained in the bath beneath the drawing zone by a refractory member and the molten material pool is thermally conditioned to maintain a predetermined temperature profile in at least part of the drawing zone.
Claims17
In a process of manufacturing flat glass by drawing glass upwardly as a continuous ribbon from a bath of molten glass held in a drawing kiln via a drawing meniscus located at the surface of such bath in the drawing zone of the kiln, into which zone forward and reverse currents of glass, originating from a main current of molten glass which flows into such zone from a region to which glass is continuously supplied, flow in respectively opposite directions along such surface toward the meniscus, the improvement comprising the steps of:
- maintaining completely immersed in the bath, beneath at least part of the drawing zone and spaced above the bottom of the bath, at least one pool of molten material;
- providing heat exchange means outside the pool;
- and withdrawing heat from such pool by effecting a heat exchange between the pool and the means, for maintaining a predetermined temperature profile in such part of the drawing zone, said step of withdrawing heat being carried out to withdraw heat to a greater extent at a region of the bath located at a central portion of the length of the drawing zone than at a region located at an end portion of the length of the drawing zone in a manner to reduce the temperature gradient in the bath along the line between such central and end portions.
In a process of manufacturing flat glass by drawing glass upwardly as a continuous ribbon from a bath of molten glass held in a drawing kiln via a drawing meniscus located at the surface of such bath in the drawing zone of the kiln, into which zone forward and reverse currents of glass, originating from a main current of molten glass which flows into such zone from a region to which glass is continuously supplied, flow in respectively opposite directions along such surface toward the meniscus, the improvement comprising the steps of:
- maintaining completely immersed in the bath, beneath at least part of the drawing zone and spaced above the bottom of the bath, two pools of molten material, with one such pool underlying the forward surface current and the other such pool underlying the reverse current at the drawing zone;
- providing heat exchange means outside the pools;
- and withdrawing heat from such pools by effecting a heat exchange between the pools and the means, for maintaining a predetermined temperature profile in such part of the drawing zone, said step of withdrawing heat being carried out to withdraw heat to a greater extent from molten material of the pool underlying the forward current than from molten material of the pool underlying the reverse current in a manner to reduce the temperature difference between the glass in the forward current and the glass in the reverse current at the drawing zone.
In apparatus for manufacturing flat glass by drawing, including a feed channel along which molten glass is continuously fed from one end thereof and means for drawing glass upwardly as a continuous ribbon from the surface of the molten glass in such channel at a drawing zone disposed between the one end and a remote end of the channel, whereby molten glass fed from the channel flows along such surface in respectively opposite directions into the ribbon via a drawing meniscus, the improvement comprising at least one refractory member located in said channel and holding at least one pool of molten material completely immersed in the molten glass in such channel, beneath said drawing zone, said refractory member being shaped to withdraw heat from the glass to a greater extent at a central portion of the length of the drawing zone than at the end portions of the length of the drawing zone in a manner to reduce the temperature gradient in the bath along the line between such central portion and such end portions.
In apparatus for manufacturing flat glass by drawing, including a feed channel along which molten glass is continuously fed from one end, and a drawing kiln at the other end of the channel, and means for drawing glass upwardly as a continuous ribbon from the surface of the molten glass in the drawing zone of such kiln, into which zone forward and reverse currents of molten glass originating from the main current of molten glass fed by the channel flow along such surface in respectively opposite directions into the ribbon via a drawing meniscus, the improvement comprising at least one refractory member located in said kiln and holding at least one pool of molten material completely immersed in the molten glass in said kiln, beneath said drawing zone, and spaced above the bottom of the molten glass in said kiln, heat exchange means, and cooling means placing said pool in heat exchange communication with said heat exchange means for withdrawing heat from said pool to maintain a predetermined temperature profile in at least part of said drawing zone, wherein said refractory member extends over substantially the full length of the drawing zone and has an upper surface which is upwardly convexly curved in the plane of the ribbon being drawn, and said member is shaped for confining said pool to a central part of the length of said member whereby withdrawal of heat from said pool results in the withdrawal of heat to a greater extent at a region of the bath located at a central portion of the length of the drawing zone than at a region located at an end portion of the length of the drawing zone in a manner to reduce the temperature gradient in the bath along the line between such central and end portions.
In apparatus for manufacturing flat glass by drawing, including a feed channel along which molten glass is continuously fed from one end, and a drawing kiln at the other end of the channel, and means for drawing glass upwardly as a continuous ribbon from the surface of the molten glass in the drawing zone of such kiln, into which zone forward and reverse currents of molten glass originating from the main current of molten glass fed by the channel flow along such surface in respectively opposite directions into the ribbon via a drawing meniscus, the improvement comprising:
- at least one refractory member located in said kiln and holding two pools of molten material completely immersed in the molten glass in said kiln, beneath said drawing zone, and spaced above the bottom of the molten glass in said kiln, a first one of said pools being located beneath the forward current and the second one of said pools being located beneath the reverse current;
- heat exchange means;
- and cooling means placing at least said first pool in heat exchange communication with said heat exchange means for withdrawing heat from at least said first pool to maintain a predetermined temperature profile in at least part of said drawing zone, said cooling means causing heat to be withdrawn from said first pool to a greater extent than from said second pool in a manner to reduce the temperature difference between the glass in the forward current and the glass in the reverse current at the drawing zone;
- wherein said first pool is dimensioned to extend only along the central portion of the length of the drawing zone to withdraw heat from glass in the forward current to a greater extent at a central portion of the length of the drawing zone than at the end portions of the length of the drawing zone in a manner to reduce the temperature gradient in the forward current along the line between the central portions and the end portions.
Dependencies are inferred from the claim text.