US2697520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method in making of filter apparatus
Assignee: Individual
•
Filing: 1952-05-13
•
Granted: 1954-12-21
•
Expires: 1972-05-13
Abstract
No abstract record available.
Inventors
- 👤 Ellila Karl Lauri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:34
CPC Classifications
B; B01; B01D; B01D24/00; B01D24/02; B01D24/20; B01D24/24; B01D24/46; B01D24/4626; B01D24/4631
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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GB406025A
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US1998279A
Cited
FR834773A
Cited
US2233981A
Cited
US2572097A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-12-20 | 1958-06-21 | 1958-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-12-20 | 1962-06-21 | 1962-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-12-20 | 1966-06-21 | 1966-12-21 | $7700.00 | Window Closed / Lapsed |