Process and apparatus for refining molten glass

Patent metadata

Field	Value
Publication number	US-9249042-B2
Application number	US-201313782638-A
Country	US
Kind code	B2
Filing date	Mar 1, 2013
Priority date	Mar 1, 2013
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A process and an apparatus for refining molten glass by introducing, a stream of unrefined molten glass into a controlled environment distributing the stream of molten glass over a flow surface, and collecting the stream of molten glass from a downstream end of the flow surface to form a body of molten glass having a free surface exposed to the controlled environment. The controlled environment, may have a pressure less than ambient atmospheric pressure, such that introducing the stream of molten glass into the controlled environment causes gaseous inclusions in the stream of molten glass to rise to a surface thereof and escape.

First claim

The invention claimed is:

1. A process for refining molten glass including:
(a) introducing molten glass into a controlled environment;
(b) distributing the molten glass over and down a downward sloping flow surface having a length extending in a flow direction of the molten glass and a width extending transverse to the flow direction of the molten glass, wherein the width of the flow surface expands along at least a portion of the length of the flow surface such that a surface area of the molten glass is increased as the molten glass flows over and down the flow surface;
(c) collecting the molten glass from a downstream end of the flow surface to form a body of molten glass having a free surface exposed to the controlled environment; and
(d) discharging molten glass from the controlled environment at a location below the free surface of the body of molten glass.

2. The process as set forth in claim 1 wherein step (a) includes introducing molten glass into the controlled environment at a location above the free surface of the body of molten glass.

3. The process as set forth in claim 1 wherein step (a) includes introducing molten glass into a sub-atmospheric environment.

4. The process as set forth in claim 3 wherein a residence time for a volume of molten glass in the sub-atmospheric environment is controlled by controlling the pressure within the sub-atmospheric environment.

5. The process as set forth in claim 1 wherein the molten glass introduced into the controlled environment in step (a) has a thickness, and step (b) includes reducing the thickness of the molten glass.

6. The process as set forth in claim 1 wherein the flow surface has a trailing edge located above the free surface of the body of molten glass, and step (c) includes collecting molten glass from the trailing edge of the flow surface.

7. The process as set forth in claim 1 wherein the flow surface has a trailing edge located below the free surface of the body of molten glass, and step (c) includes collecting molten glass from the trailing edge of the flow surface.

8. The process as set forth in claim 1 wherein step (c) includes collecting the molten glass within a reservoir section.

9. The process as set forth in claim 8 wherein the molten glass is received at an open end of the reservoir section.

10. The process as set forth in claim 8 wherein the molten glass is collected above a submerged end of the reservoir section.

11. The process as set forth in claim 10 wherein molten glass is discharged from the controlled environment in step (d) via an opening in the submerged end of the reservoir section.

12. The process as set forth in claim 1 wherein molten glass is discharged from the controlled environment in step (d) without use of a mechanical pump.

13. The process as set forth in claim 1 wherein step (b) includes heating the molten glass as the molten glass is distributed over the flow surface.

14. A refining chamber for refining molten glass including:
an inlet for receiving molten glass;
a distribution section for distributing molten glass over a downward sloping flow surface, the flow surface having a length extending in a molten glass flow direction and a width extending transverse to the molten glass flow direction, wherein the width of the flow surface expands along at least a portion of the length of the flow surface such that the flow surface increases in surface area as the flow surface extends in a downward direction;
a reservoir section that receives and collects molten glass from the distribution section;
and an outlet through which molten glass is discharged, said outlet being located below a free surface of a body of molten glass that has been collected within the reservoir section.

15. The refining chamber as set forth in claim 14 wherein the distribution section and the reservoir section together define a path for molten glass to flow from the inlet to the outlet of the refining chamber.

16. The refining chamber as set forth in claim 14 further including an evacuation system including a vacuum pump and an evacuation conduit for producing a sub-atmospheric environment within the refining chamber.

17. The refining chamber as set forth in claim 14 wherein the flow surface extends from the inlet of the refining chamber to the reservoir section.

18. The refining chamber as set forth in claim 14 wherein the flow surface increases in surface area from a leading edge to a trailing edge thereof.

19. The refining chamber as set forth in claim 14 wherein the flow surface has an expanding width section.

20. The refining chamber as set forth in claim 14 wherein the flow surface has an expanding width section and a constant width section.

21. The refining chamber as set forth in claim 14 wherein the flow surface is at least partially defined by walls, which divert from each other with respect to the molten class flow direction.

22. The refining chamber as set forth in claim 14 wherein the reservoir section includes an open end through which molten glass is received from the distribution section.

23. The refining chamber as set forth in claim 14 wherein the reservoir section includes a submerged end in which molten glass is collected.

24. The refining chamber as set forth in claim 23 wherein the submerged end of the reservoir section includes an opening through which molten glass is discharged from the reservoir section.

25. The refining chamber as set forth in claim 14 further including a device for stirring or agitating a body of molten glass that has been collected within the reservoir section.

26. An apparatus for making glass including the refining chamber set forth in claim 14 .

27. The apparatus as set forth in claim 26 wherein the inlet of the refining chamber is configured to receive molten glass from a melting chamber and is positioned below a free surface of a body of molten glass held within the melting chamber.

28. The apparatus as set forth in claim 26 including:
a homogenization chamber positioned downstream of the refining chamber in which molten glass is homogenized; and
a submerged passageway through which molten glass can flow from the refining chamber to the homogenization chamber, the submerged passageway having an inlet and an outlet positioned below a body of molten glass held within the refining chamber and below a body of molten glass held within the homogenization chamber such that the submerged passageway provides a trap for preventing gas flow through the submerged passageway into the refining chamber.

29. An apparatus for making glass including:
a melting chamber for melting glass-forming materials to produce a first body of molten glass having a first free surface exposed to an atmospheric pressure environment;
an enclosed refining chamber positioned downstream of the melting chamber for refining molten glass, the refining chamber including:
an inlet for receiving molten glass from the melting chamber;
a distribution section for distributing the molten glass over a downward sloping flow surface, the flow surface having a length extending in a flow direction of the molten glass and a width extending transverse to the flow direction of the molten glass, wherein the width of the flow surface expands along at least a portion of the length of the flow surface such that the flow surface increases in surface area

Assignees

• Owens Brockway Glass Container

Inventors

• Wang Zhongming
• Howse Terence K G

Classifications

• C03B5/20

  Bridges, shoes, throats, or other devices for withholding dirt, foam, or batch · CPC title

• C03B5/26

  Outlets {, e.g. drains, siphons}; Overflows {, e.g. for supplying the float tank, tweels} · CPC title

• C03B5/2252 Primary

  under reduced pressure, e.g. with vacuum refiners · CPC title

• C03B5/187

  with moving elements · CPC title

• C03B5/2257

  by thin-layer fining · CPC title