Patent US3397440A successfully refreshed from Google Patents.
US3397440A
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US
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Method of making heat exchanger having extended surface
Assignee: Individual
•
Filing: 1965-09-30
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Granted: 1968-08-20
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Expires: 1985-09-30
Abstract
No abstract record available.
Inventors
- 👤 Dalin David
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:18
CPC Classifications
B; B21; B21C; B21C37/00; B21C37/06; B21C37/15; B21C37/22; B21C37/26; F; F28; F28F; F28F1/00; F28F1/10; F28F1/12; F28F1/122; F28F1/34; F28F1/36; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49377; Y10T29/49378; Y10T29/49382
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2824212A
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US3045979A
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US3053511A
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US3226808A
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US3158122A
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US3220107A
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US3288209A
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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) | 1971-08-20 | 1972-02-19 | 1972-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-08-20 | 1976-02-19 | 1976-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-08-20 | 1980-02-19 | 1980-08-20 | $7700.00 | Window Closed / Lapsed |