Patent US2704973A successfully refreshed from Google Patents.
US2704973A
Expired / Lapsed
US
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Ventilating system
Assignee: Phillips Petroleum Co
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Filing: 1950-05-22
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Granted: 1955-03-29
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Expires: 1970-05-22
Abstract
No abstract record available.
Inventors
- 👤 Jr Victor L Hayes
- 👤 Frank S Hamlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:38
CPC Classifications
B; B08; B08B; B08B15/00; B08B15/02; B08B15/023; F; F23; F23J; F23J11/00; F23J11/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1624107A
Cited
US1183397A
Cited
CH75419A
Cited
US1847736A
Cited
US2438606A
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US2549042A
Cited
US2627220A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-03-28 | 1958-09-27 | 1959-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-03-28 | 1962-09-27 | 1963-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-03-28 | 1966-09-27 | 1967-03-29 | $7700.00 | Window Closed / Lapsed |