Patent US4632686A successfully refreshed from Google Patents.
US4632686A
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US
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Method of manufacturing quartz glass crucibles with low bubble content
Assignee: Osram Sylvania Inc
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Filing: 1986-02-24
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Granted: 1986-12-30
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Expires: 2006-02-24
Abstract
Abstract In the manufacture of a quartz glass crucible of low bubble content, a first layer of granular quartz material is disposed on the interior of a rotating mold through the walls of which a vacuum can be drawn. A second layer of finer quartz material is then disposed on the first layer. The quartz material is then heated, melted and fused to form a crucible.
Inventors
- 👤 David R. Brown
- 👤 Charles E. Frost, Jr.
- 👤 Kenneth A. White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:28
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/09; C03B19/095
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
126 words
The method of making a quartz glass crucible of low bubble content comprising the steps of preparing a mold having holes therethrough through which a vacuum can be drawn, disposing the mold on a rotatable spindle through which a vacuum can be drawn, rotating the mold while drawing a vacuum on the interior of the mold through said holes, pouring granular quartz material into the mold to form a first layer thereof on the interior of the mold, pouring quartz material finer than said granular quartz material into the mold to form a second layer thereof on the first layer, applying heat to the interior of the mold to melt and fuse the quartz material to form a crucible, and removing the crucible from the mold.
Claim 2
Independent Claim
126 words
The method of making a quartz glass crucible of low bubble content comprising the steps of preparing a mold having holes therethrough through which a vacuum can be drawn, disposing the mold on a rotatable spindle through which a vacuum can be drawn, rotating the mold while drawing a vacuum on the interior of the mold through said holes, pouring granular quartz material into the mold to form a first layer thereof on the interior of the mold, pouring quartz material finer than said granular quartz material into the mold to form a second layer thereof on the first layer, applying heat to the interior of the mold to melt and fuse the quartz material to form a crucible, and removing the crucible from the mold.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the granular quartz material has a particle size distribution of about 297 to 105 microns.
Claim 4
Dependent Claim
21 words
The method of claim 2 wherein the finer quartz material has a particle size distribution of about 120 to 44 microns.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |