Method and apparatus for reducing sheet width attenuation of sheet glass

Patent metadata

Field	Value
Publication number	US-2019330094-A1
Application number	US-201916507588-A
Country	US
Kind code	A1
Filing date	Jul 10, 2019
Priority date	Oct 3, 2014
Publication date	Oct 31, 2019
Grant date	—

Abstract

Disclosed herein are apparatuses and methods for drawing sheet glass. More particularly, one or more sets of edge rolls can be configured to have a rotation axis angled away from a line orthogonal to the direction of flow of a ribbon of glass and positioned so as to contact the glass in the viscous region of the draw. Through control over the orientation and position of the one or more sets of edge rolls, sheet width attenuation may be eliminated, thickness of the beads that form along the edges of the glass sheet may be reduced, and instabilities associated with sheet width variation may be eliminated.

First claim

What is claimed is:

1 . An apparatus for drawing sheet glass comprising:
a forming wedge having a pair of forming surfaces, the forming wedge being configured to provide for a flow of molten glass down the pair of forming surfaces to join at a root to form a viscous ribbon of glass; a first pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the first pair of edge rolls are positioned at about a first location of 7 centimeters below the root; and a second pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the second pair of edge rolls are positioned at about a second location of 15 centimeters below the root.

2 . The apparatus of claim 1 , wherein the first pair of edge rolls contact a first edge of the viscous ribbon of glass, and the second pair of edge rolls contact a second edge of the viscous ribbon of glass.

3 . The apparatus of claim 1 , comprising:
a third pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the third pair of edge rolls are positioned at about the first location; and a fourth pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the fourth pair of edge rolls are positioned at about the second location.

4 . The apparatus of claim 3 , wherein:
the first pair of edge rolls and the third pair of edge rolls are configured to contact the viscous ribbon of glass with a substantially smooth contact surface along the first and second sides; and the second pair of edge rolls and the fourth pair of edge rolls are configured to contact the viscous ribbon of glass with a knurled contact surface along the first and second sides.

5 . The apparatus of claim 1 , wherein the first pair of edge rolls are oriented to provide a rotation axis that forms an angle of about 5 degrees from a first line orthogonal to movement of the viscous ribbon of glass.

6 . The apparatus of claim 1 , wherein the second pair of edge rolls are oriented to provide a rotation axis that forms an angle of about 20 degrees from a first line orthogonal to movement of the viscous ribbon of glass.

7 . The apparatus of claim 1 , wherein the first pair of edge rolls are configured to contact the viscous ribbon of glass with a substantially smooth contact surface along the first and second sides.

8 . The apparatus of claim 1 , wherein the second pair of edge rolls are configured to contact the viscous ribbon of glass with a knurled contact surface along the first and second sides.

9 . An apparatus for longitudinally drawing a viscous ribbon of glass having a first side and an opposing second side, a first edge and a second edge that opposes the first edge, and a width defined by a distance between the first and second edges, comprising:
a forming wedge having a pair of forming surfaces, the forming wedge being configured to provide for a flow of molten glass down the pair of forming surfaces to join at a root to form the viscous ribbon of glass; a first pair of edge rolls configured to contact the viscous ribbon of glass with a first substantially smooth contact surface along the first and second sides near the first edge; and a second pair of edge rolls configured to contact the viscous ribbon of glass with a first knurled contact surface along the first and second sides near the second edge.

10 . The apparatus of claim 9 , wherein at least one of the first pair of edge rolls and the second pair of edge rolls are oriented to provide a rotation axis that forms an angle between about 3 degrees and about 55 degrees from a first line orthogonal to movement of the viscous ribbon of glass.

11 . The apparatus of claim 9 , wherein the first pair of edge rolls and the second pair of edge rolls are positioned no further than 25 centimeters from the root.

12 . The apparatus of claim 9 , further comprising:
a third pair of edge rolls to contact the viscous ribbon of glass with a second substantially knurled contact surface along the first and second sides near the first edge; and a fourth pair of edge rolls configured to contact the viscous ribbon of glass with a second smooth contact surface along the first and second sides near the second edge.

13 . The apparatus of claim 12 , wherein the first pair of edge rolls and the second pair of edge rolls are aligned with each other along a first line orthogonal to movement of the viscous ribbon of glass.

14 . The apparatus of claim 13 , wherein the third pair of edge rolls and the fourth pair of edge rolls are aligned with each other along a second line orthogonal to movement of the viscous ribbon of glass.

15 . A method for reducing glass sheet width attenuation comprising passing a viscous ribbon of glass from a root of a forming wedge through:
a first pair of edge rolls configured to contact a first edge of the viscous ribbon of glass along the front and back sides; and a second pair of edge rolls configured to contact a second edge of the viscous ribbon of glass along the front and back sides, wherein the first pair of edge rolls and the second pair of edge rolls are aligned along a first line orthogonal to movement of the viscous ribbon of glass, wherein at least one of the first pair of edge rolls and the second pair of edge rolls are oriented to provide a rotation axis that forms an angle between about 3 degrees and about 55 degrees from the first line, and wherein the angle of the first and second pairs of edge rolls and a location of the first line are selected to produce a glass sheet with a width that is greater than the width of the viscous ribbon of glass at the root.

16 . The method of claim 15 , the angle of the first and second pairs of edge rolls and the location of the first line are selected to produce the glass sheet having a ratio of bead thickness to center thickness that is less than about 5.

17 . A method for reducing glass sheet width attenuation comprising passing a viscous ribbon of glass from a root of a forming wedge through:
a first pair of edge rolls configured to contact the viscous ribbon of glass along a front side and a back side, wherein the first pair of edge rolls are positioned at about a first location of 7 centimeters below the root; and a second pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the second pair of edge rolls are positioned at about a second location of 15 centimeters below the root.

18 . The method of claim 17 , wherein the first pair of edge rolls contact a first edge of the viscous ribbon of glass, and the second pair of edge rolls contact a second edge of the viscous ribbon of glass.

19 . The method of claim 17 further comprising passing the viscous ribbon of glass through:
a third pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the third pair of edge rolls are positioned at about the first location; and
a fourth pair of edge rolls configured to contact the viscous ribbon of glass along the front and back sides, wherein the fourth pair of edge rolls are positioned at about the second location.

20 . The method of claim 19 , wherein:
the first pair of edge rolls and the third pair of edge rolls are configured to contact the viscous ribbon of glass with a substantially smooth contact surface along the first and second sides; and the second pair of edge

Assignees

• Corning Inc

Inventors

• Boratav Olus Naili
• Peng Gaozhu
• Whedon William Anthony

Classifications

• C03B17/064 Primary

  by the overflow downdraw fusion process; Isopipes therefor · CPC title

• C03B17/068 Primary

  Means for providing the drawing force, e.g. traction or draw rollers · CPC title

• Y02P40/57

  Improving the yield, e-g- reduction of reject rates · CPC title