Patent US3695976A successfully refreshed from Google Patents.
Patent US2682391A successfully refreshed from Google Patents.
US2682391A
Expired / Lapsed
US
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Heat exchanger with removable liner
Assignee: Individual
•
Filing: 1951-02-01
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Granted: 1954-06-29
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Expires: 1971-02-01
Abstract
No abstract record available.
Inventors
- 👤 Thomas F Downs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:17
CPC Classifications
F; F28; F28F; F28F19/00; F28F19/02; F28F19/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US830695A
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US935876A
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GB294687A
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US1827381A
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US1899099A
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US2187555A
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GB520644A
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US2320207A
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US2524117A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-06-28 | 1957-12-28 | 1958-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-06-28 | 1961-12-28 | 1962-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-06-28 | 1965-12-28 | 1966-06-29 | $7700.00 | Window Closed / Lapsed |