Patent US2640686A successfully refreshed from Google Patents.
US2640686A
Expired / Lapsed
US
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Heat exchange type of tank heater
Assignee: Brown Fintube Co
•
Filing: 1949-08-30
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Granted: 1953-06-02
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Expires: 1969-08-30
Abstract
No abstract record available.
Inventors
- 👤 Jr John W Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:38
CPC Classifications
F; F28; F28F; F28F9/00; F28F9/02; F28F9/0243; F23; F23K; F23K5/00; F23K5/02; F23K5/14; F23K5/20; F28D; F28D1/00; F28D1/02; F28D1/0206; F28D1/0213
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1988694A
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US2149954A
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US2254070A
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US2410999A
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US2449052A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-01 | 1956-12-01 | 1957-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-01 | 1960-12-01 | 1961-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-01 | 1964-12-01 | 1965-06-02 | $7700.00 | Window Closed / Lapsed |