US2021937A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for removing so2 from flue gases
Assignee: University of Illinois at Urbana-Champaign
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Filing: 1931-12-19
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Granted: 1935-11-26
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Expires: 1951-12-19
Abstract
No abstract record available.
Inventors
- 👤 Henry F Johnstone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:06
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8603; B01D53/8609
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) | 1938-11-25 | 1939-05-27 | 1939-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-11-25 | 1943-05-27 | 1943-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-11-25 | 1947-05-27 | 1947-11-26 | $7700.00 | Window Closed / Lapsed |