Patent US2677944A successfully refreshed from Google Patents.
US2677944A
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US
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Plural stage refrigeration apparatus
Assignee: Individual
•
Filing: 1950-12-01
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Granted: 1954-05-11
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Expires: 1970-12-01
Abstract
No abstract record available.
Inventors
- 👤 Alonzo W Ruff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:37
CPC Classifications
F; F04; F04C; F04C29/00; F04C29/04; F04C27/00; F04C27/008; F04C27/009; F25; F25B; F25B1/00; F25B1/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US302294A
Cited
US580049A
Cited
US1364246A
Cited
US1732039A
Cited
US1979525A
Cited
US1905521A
Cited
DE696640C
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-05-10 | 1957-11-09 | 1958-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-05-10 | 1961-11-09 | 1962-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-05-10 | 1965-11-09 | 1966-05-11 | $7700.00 | Window Closed / Lapsed |