US3421297A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sealing device for roll-type filter
Assignee: American Air Filter Co Inc
•
Filing: 1967-12-13
•
Granted: 1969-01-14
•
Expires: 1987-12-13
Abstract
No abstract record available.
Inventors
- 👤 Francis E Dahlem
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:27
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2732912A
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US2125574A
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US2473501A
Cited
US2881859A
Cited
GB746162A
Cited
US2867324A
Cited
US3071060A
Cited
US3201272A
Cited
US3348366A
Cited
US3342123A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-01-14 | 1972-07-15 | 1973-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-01-14 | 1976-07-15 | 1977-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-01-14 | 1980-07-15 | 1981-01-14 | $7700.00 | Window Closed / Lapsed |