Glass sheet forming apparatus

• US 20050268658A1
• Filed: 06/02/2004
• Published: 12/08/2005
• Est. Priority Date: 06/02/2004
• Status: Abandoned Application

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Adamowicz, John A., Rhoads, Randy L., Boratav, Olus N.
• Application Number:
  US10/859,248
• Publication Number:
  US 20050268658A1
• Time in Patent Office: Days
• US Class Current: 65/53
• CPC Class Codes: C03B 17/064 by the overflow downdraw fusion process; Isopipes therefor

Abstract

A forming apparatus (635) is described herein that is used in a glass manufacturing system (100) to form a glass sheet (605). The forming apparatus (635) includes a body (722) having an inlet (702) that receives molten glass (626) which flows into a trough (706) formed in the body (722) and then overflows two top surfaces (726a and 726b) of the trough (706) and runs down two sides (708a and 708b) of the body (722) before fusing together where the two sides (708a and 708b) come together to form a glass sheet (605). The trough (706) has a bottom surface (716) and an embedded object (718) formed thereon that are both sized to cause a desired mass distribution of the molten glass (626) to overflow the top surfaces (726a and 726b) of the trough (706) to enable the production of the glass sheet (605).

Claims

1. A forming apparatus characterized by:

a body having an inlet that receives molten glass which flows into a trough formed in said body and then overflows two top surfaces of the trough and runs down two sides of said body before fusing together where the two sides come together to form a glass sheet, wherein said trough has a bottom surface and an embedded object formed thereon that are both sized to cause a desired mass distribution of the molten glass to overflow the top surfaces of said trough to facilitate production of said glass sheet.

2. The forming apparatus of claim 1, wherein said trough has a height between the bottom surface and the top surfaces that varies in a predetermined manner as the bottom surface extends away from the inlet.

3. The forming apparatus of claim 1, wherein said embedded object is located near an end of said trough which is opposite the inlet to said trough.

4. The forming apparatus of claim 1, wherein said trough including the bottom surface and the embedded object have geometries determined by using physical modeling.

5. The forming apparatus of claim 1, wherein said trough including the bottom surface and the embedded object have geometries determined by using mathematical modeling.

6. The forming apparatus of claim 1, wherein said embedded object is an object that has a diverging cross-sectional shape.

7. The forming apparatus of claim 1, wherein said embedded object directs the molten glass away from a channel symmetry axis in said trough.

8. An apparatus for forming a glass sheet, said apparatus characterized by a body member having exterior side walls with downwardly converging portions, an upwardly open trough formed in an upper surface of said body member having bounding walls with top surfaces, said exterior side walls terminating at their exterior extent at said top surfaces, said body member having an inlet in which molten glass is supplied at one end of said upwardly open trough, said upwardly open trough having an bottom surface and an embedded object where both are sized to enable a substantially uniform mass of molten glass to overflow along the extent of said top surfaces to facilitate the production of said glass sheet.

9. The apparatus of claim 8, wherein said upwardly open trough has a height between the bottom surface and the top surfaces that varies in a predetermined manner as the bottom surface extends away from the inlet.

10. The apparatus of claim 8, wherein said upwardly open trough including the bottom surface and the embedded object are sized to enable substantially the same mass distribution of molten glass as a traditional upwardly open trough including only an bottom surface that has a flow rate of molten glass in accordance with:

$Q=\frac{\mathrm{\rho <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>g<br><br>\text{\hspace{1em}<br><br>}<br><br>\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\varphi <br><br>}}{3<br><br>\mathrm{\mu <br><br>}}<br><br>w^4<br><br>{\mathrm{\alpha <br><br>}}^3<br><br>\left[1-\frac{3}{8}<br><br>\underset{n=0}{\overset{\mathrm{\infty <br><br>}}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>\frac{\mathrm{\alpha <br><br>}}{{\mathrm{\beta <br><br>}}_n^5}<br><br>\tanh <br><br>\left({\mathrm{\beta <br><br>}}_n/\mathrm{\alpha <br><br>}\right)\right]$

where

Q=the flow rate at any cross section of the traditional upwardly open trough;

w=the channel width of the traditional upwardly open trough;

α

=the aspect ratio or height over width of the traditional upwardly open trough;

β

_n=a variable given by (2n+1)/π

/4;

ρ

=density of the molten glass;

μ

=viscosity of the molten glass;

φ

=angle between a horizontal plane and parallel upper surfaces on the traditional upwardly open trough;

g=980 cm/sec²;

wherein when ρ

, μ

, φ and

w⁴α

³ are kept the same between said upwardly open trough and said traditional upwardly open trough then there is at least one geometry for the embedded object which would cause said upwardly open trough to have substantially the same mass distribution of molten glass as the traditional upwardly open trough.

11. The apparatus of claim 8, wherein said embedded object is located near an end of said upwardly open trough which is opposite the inlet to said upwardly open trough.

12. The apparatus of claim 8, wherein said upwardly open trough including the bottom surface and the embedded object have geometries determined by using physical modeling.

13. The apparatus of claim 8, wherein said upwardly open trough including the bottom surface and the embedded object have geometries determined by using mathematical modeling.

14. The apparatus of claim 8, wherein said embedded object is one of the following:

a diverging rectangular cross-sectional shaped embedded object;

a semi-elliptical/circular cross-sectional shaped embedded object;

a triangular cross-sectional shaped embedded object;

or

a trapezoidal cross-sectional shaped embedded object.

15. The apparatus of claim 8, wherein said embedded object directs the molten glass away from a channel symmetry axis in said trough.

16. A glass manufacturing system characterized by:

at least one vessel for melting batch materials; and

a forming apparatus for receiving the melted batch materials and forming a glass sheet, wherein said forming apparatus includes;

a body having an inlet that receives molten glass which flows into a trough formed in said body and then overflows two top surfaces of the trough and runs down two sides of said body before fusing together where the two sides come together to form a glass sheet, wherein said trough has an bottom surface and an embedded object formed thereon that are both sized to cause a desired mass distribution of the molten glass to overflow the top surfaces of said trough to facilitate production of said glass sheet.

17. The glass manufacturing system of claim 16, wherein said at least one vessel includes a melting, fining, mixing or delivery vessel.

18. A glass sheet formed by a glass manufacturing system that includes:

at least one vessel for melting batch materials and forming molten glass; and

a forming apparatus for receiving the molten glass and forming the glass sheet, wherein said forming apparatus includes;

a body having an inlet that receives molten glass which flows into a trough formed in said body and then overflows two top surfaces of the trough and runs down two sides of said body before fusing together where the two sides come together to form a glass sheet, wherein said trough has an bottom surface and an embedded object formed thereon that are both sized to cause a desired mass distribution of the molten glass to overflow the top surfaces of said trough to facilitate production of said glass sheet.

19. The glass sheet of claim 18, wherein said at least one vessel includes a melting, fining, mixing or delivery vessel.