Patent US3834995A successfully refreshed from Google Patents.
Patent US2491434A successfully refreshed from Google Patents.
US2491434A
Expired / Lapsed
US
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Combination power plant and heating system
Assignee: Bituminous Coal Research Inc
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Filing: 1947-04-25
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Granted: 1949-12-13
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Expires: 1967-04-25
Abstract
No abstract record available.
Inventors
- 👤 John I Yellott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:35
CPC Classifications
F; F02; F02C; F02C6/00; F02C6/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1948539A
Cited
US2076382A
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US2152479A
Cited
US2193114A
Cited
US2192759A
Cited
US2263705A
Cited
US2452581A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-12-12 | 1953-06-13 | 1953-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-12-12 | 1957-06-13 | 1957-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-12-12 | 1961-06-13 | 1961-12-13 | $7700.00 | Window Closed / Lapsed |