Patent US2638878A successfully refreshed from Google Patents.
US2638878A
Expired / Lapsed
US
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Water heater having extensive heat transfer surfaces
Assignee: Vapor Heating Corp
•
Filing: 1951-01-19
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Granted: 1953-05-19
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Expires: 1971-01-19
Abstract
No abstract record available.
Inventors
- 👤 Jr Albert Lemos
- 👤 Jr Richard Cunningham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:23
CPC Classifications
F; F24; F24H; F24H1/00; F24H1/22; F24H1/24; F24H1/26; F24H1/28; F24H1/282; F24H1/18; F24H1/20; F24H1/205
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1742063A
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US1781532A
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US1880533A
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Cited
US2321109A
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US2187917A
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US2225606A
Cited
US2288021A
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US2531459A
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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) | 1956-05-18 | 1956-11-17 | 1957-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-18 | 1960-11-17 | 1961-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-18 | 1964-11-17 | 1965-05-19 | $7700.00 | Window Closed / Lapsed |