Patent US1971668A successfully refreshed from Google Patents.
US1971668A
Expired / Lapsed
US
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Process for the production of monobasic aluminum sulphite
Assignee: Evonik Operations GmbH
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Filing: 1933-01-23
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Granted: 1934-08-28
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Expires: 1953-01-23
Abstract
No abstract record available.
Inventors
- 👤 Wiedbrauck Erich
- 👤 Buche Karl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:23
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/68; C01F7/72
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) | 1937-08-27 | 1938-02-26 | 1938-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1941-08-27 | 1942-02-26 | 1942-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1945-08-27 | 1946-02-26 | 1946-08-28 | $7700.00 | Window Closed / Lapsed |