US2525400A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air heater with solid fuel and fluid fuel burning furnaces arranged in tandem
Assignee: Individual
•
Filing: 1946-06-26
•
Granted: 1950-10-10
•
Expires: 1966-06-26
Abstract
No abstract record available.
Inventors
- 👤 Raymond F Crawford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:22
CPC Classifications
F; F24; F24H; F24H3/00; F24H3/02; F24H3/06; F24H3/08; F24H3/087; F24H15/00; F24H15/20; F24H15/208; F24H15/30; F24H15/355; F24H15/36; F24H9/00; F24H9/20; F24H9/2064
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-10-09 | 1954-04-10 | 1954-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-10-09 | 1958-04-10 | 1958-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-10-09 | 1962-04-10 | 1962-10-10 | $7700.00 | Window Closed / Lapsed |