Patent EP0371457A2 successfully refreshed from Google Patents.
US3620702A
Expired / Lapsed
US
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Process improvement for manufacturing high-purity quartz forms
Assignee: Corning Glass Works
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Filing: 1969-10-28
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Granted: 1971-11-16
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Expires: 1989-10-28
Abstract
Abstract Improvement during the step of firing a high-purity quartz form whereby the end-supported green quartz form is heated along at least one narrow-band section by a heat source capable of at least attaining the melting point of quartz and the supported form and heat source are moved relative to one another for a time sufficient to completely fire the form. The moving speed may be varied as the firing progresses in order to maintain optimum dimensional stability.
Inventors
- 👤 Arthur Dekalb
- 👤 Alan G Whitney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:13
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
82 words
The process of claim 1 wherein said heat source comprises one top center burner for heating the central bottom portion of said crucible, multiple side burners for heating the side portion of said crucible and multiple top-side burners for heating the transitional portion joining said bottom and side portions of said crucible, said multiple side and top-side burners being generally aligned and equally spaced from and around said crucible; and said narrow-band vertical section ranges from 0.125 to 0.50 inches in width.
Claim 2
Dependent Claim
61 words
The process of claim 1 with the additional step of decreasing said rotational speed between said initial and final heating steps, in order to keep the dimensional shrinkage of said crucible from the slip-cast green stage to the completely fused amorphous quartz stage as uniform as possible, with about 70 percent of the dimensional shrinkage occurring during said initial heating step.
References Cited (Backward Citations)
US1778305A
Cited
US2726487A
Cited
US2992903A
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US3116137A
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US3113877A
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US3177057A
Cited
US3298553A
Cited
US3360595A
Cited
US3524748A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |