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Patent US2097723A successfully refreshed from Google Patents.
US2097723A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conditioning mine air
Assignee: Individual
•
Filing: 1933-08-03
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Granted: 1937-11-02
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Expires: 1953-08-03
Abstract
No abstract record available.
Inventors
- 👤 Ewing Sydney Edward Thacker
- 👤 Egan Arthur Lindsey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:20
CPC Classifications
E; E21; E21F; E21F3/00
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) | 1940-11-01 | 1941-05-03 | 1941-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1944-11-01 | 1945-05-03 | 1945-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1948-11-01 | 1949-05-03 | 1949-11-02 | $7700.00 | Window Closed / Lapsed |