US3647709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of silica gels
Assignee: BP Chemicals Ltd
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Filing: 1969-11-24
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Granted: 1972-03-07
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Expires: 1989-11-24
Abstract
Abstract SILICA GELS FROM "DENSIFIED" SILICA SOLS E.G. "LUDOX" BY PROCESS INCLUDING A HYDROTHERMAL TREATMENT AT A TEMPERATURE FROM 100*C. TO 370*C. FOR FROM 12 TO 200 HOURS AT SUCH A PRESSURE THAT THE WATER IN THE LIQUID PHASE DOES NOT EVAPORATE.
Inventors
- 👤 Thomas Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:20
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/152
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |