US2424221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchanger
Assignee: Brown Fintube Co
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Filing: 1944-09-04
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Granted: 1947-07-22
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Expires: 1964-09-04
Abstract
No abstract record available.
Inventors
- 👤 Jr John W Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:11
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/06; F28F; F28F9/00; F28F9/02; F28F9/0219; F28F9/26; F28F2275/00; F28F2275/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-07-21 | 1951-01-20 | 1951-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-07-21 | 1955-01-20 | 1955-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-07-21 | 1959-01-20 | 1959-07-22 | $7700.00 | Window Closed / Lapsed |