Patent US2881923A successfully refreshed from Google Patents.
US2881923A
Expired / Lapsed
US
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Combined flotation and clarification device
Assignee: Dorr Oliver Inc
•
Filing: 1956-02-01
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Granted: 1959-04-14
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Expires: 1976-02-01
Abstract
No abstract record available.
Inventors
- 👤 Frederick G Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:02
CPC Classifications
B; B03; B03D; B03D1/00; B03D1/02; B03D1/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US266204A
Cited
US1253653A
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US1757263A
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US2324400A
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US2375282A
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US2406248A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-04-13 | 1962-10-13 | 1963-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-04-13 | 1966-10-13 | 1967-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-04-13 | 1970-10-13 | 1971-04-14 | $7700.00 | Window Closed / Lapsed |