US3576932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sintering vapor deposited silica on a mandrel designed to reduce shrinkage
Assignee: Texas Instruments Inc
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Filing: 1969-02-17
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Granted: 1971-04-27
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Expires: 1989-02-17
Abstract
Abstract A PROCESS FOR MANUFACTURING FUSED SILICA ARTICLES IN WHICH SILICON DIOXIDE IS DEPOSITED AND VITRIFIED ON THE SAME MANDREL. SILICON DIOXIDE FORMED BY VAPOR PAHSE HYDROLYSIS OF SILICON TETRACHLORIDE IS DEPOSITED ON A CYLINDRICAL GRAPHITE MANDREL HAVING REDUCED DEAMETER PORTIONS AT ONE OR AT EACH OF ITS ENDS WHILE THE MANDREL IS AT AN ELEVATED TEMPERATURE. THE "GREEN" SILICA ARTICLE THUS FORMED IS THEN DENSIFIED ON THE SAME MANDREL BY HEAT TREATMENT IS A CACUUM FRUNACE. INTERENGAGEMENT OF THE SILICA AND THE REDUCED DIAMETER PORTIONS OF THE MANDREL PREVENTS SHRINKAGE OF THE ARTICLE DURING HEAT TREATMENT.
Inventors
- 👤 Rulon Bruce Biddulph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:12
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/14; C03B19/1484; C03B19/1492; C03B19/06; C04; C04B; C04B35/00; C04B35/622; C04B35/62222
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |