Patent US2869834A successfully refreshed from Google Patents.
US2869834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchanger
Assignee: PATTERSON KELLEY CO
•
Filing: 1956-04-10
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Granted: 1959-01-20
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Expires: 1976-04-10
Abstract
No abstract record available.
Inventors
- 👤 Jr John A Clark
- 👤 John J Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:11
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1284868A
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US1427611A
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US1578830A
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US1957779A
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US1894692A
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US1964256A
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US2061429A
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US2535047A
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US2508815A
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US2656157A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-01-19 | 1962-07-21 | 1963-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-01-19 | 1966-07-21 | 1967-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-01-19 | 1970-07-21 | 1971-01-20 | $7700.00 | Window Closed / Lapsed |