Patent US1798261A successfully refreshed from Google Patents.
US1798261A
Expired / Lapsed
US
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Purifying alumina
Assignee: Alcoa Corp
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Filing: 1925-12-04
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Granted: 1931-03-31
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Expires: 1945-12-04
Abstract
No abstract record available.
Inventors
- 👤 Basil T Horsfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:21
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/38; C01F7/021; C01F7/027; C01F7/46; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/34
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) | 1934-03-30 | 1934-09-29 | 1935-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1938-03-30 | 1938-09-29 | 1939-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1942-03-30 | 1942-09-29 | 1943-03-31 | $7700.00 | Window Closed / Lapsed |