Patent US2540474A successfully refreshed from Google Patents.
US2540474A
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US
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Filtration system
Assignee: Akzo Nobel UK PLC
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Filing: 1947-10-31
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Granted: 1951-02-06
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Expires: 1967-10-31
Abstract
No abstract record available.
Inventors
- 👤 Charles W Cox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:15
CPC Classifications
B; B01; B01D; B01D37/00; B01D21/00; B01D21/0006; B01D21/0012; B01D21/02; B01D21/24; B01D21/2427; B01D21/26; B01D21/262; B01D29/00; B01D29/01; B01D29/05; B01D29/76; B01D29/86; B01D29/88; B01D29/90; B01D29/902
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US504434A
Cited
US871046A
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US1505898A
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US1784132A
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US2089702A
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US2245588A
Cited
GB537498A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-02-05 | 1954-08-07 | 1955-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-02-05 | 1958-08-07 | 1959-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-02-05 | 1962-08-07 | 1963-02-06 | $7700.00 | Window Closed / Lapsed |