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Patent US1893048A successfully refreshed from Google Patents.
US1893048A
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Assignee: American Air Filter Co Inc
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Filing: 1927-08-10
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Granted: 1933-01-03
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Expires: 1947-08-10
Abstract
No abstract record available.
Inventors
- 👤 Hans E Birkholz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:48
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/52; B01D46/521; B01D2275/00; B01D2275/30
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) | 1936-01-03 | 1936-07-04 | 1937-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1940-01-03 | 1940-07-04 | 1941-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1944-01-03 | 1944-07-04 | 1945-01-03 | $7700.00 | Window Closed / Lapsed |