Patent US2738928A successfully refreshed from Google Patents.
US2738928A
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US
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Heat exchange system
Assignee: LILLIAN B LIEBERMAN
•
Filing: 1952-09-03
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Granted: 1956-03-20
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Expires: 1972-09-03
Abstract
No abstract record available.
Inventors
- 👤 Nathan L Lieberman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:53
CPC Classifications
F; F24; F24D; F24D3/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1791441A
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US2141609A
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US2354982A
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US2357340A
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FR911491A
Cited
US2507624A
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US2504784A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-03-20 | 1959-09-19 | 1960-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-03-20 | 1963-09-19 | 1964-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-03-20 | 1967-09-19 | 1968-03-20 | $7700.00 | Window Closed / Lapsed |