US2913009A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Internal and internal-external surface heat exchange tubing
Assignee: Calumet and Hecla Inc
•
Filing: 1956-07-16
•
Granted: 1959-11-17
•
Expires: 1976-07-16
Abstract
No abstract record available.
Inventors
- 👤 Charles H Kuthe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:49
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/10; F28F; F28F1/00; F28F1/003; F28F2210/00; F28F2210/06; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49377; Y10T29/49378; Y10T29/49382; Y10T29/49384; Y10T29/49826; Y10T29/49879; Y10T29/49908; Y10T29/49925; Y10T29/49927
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2374609A
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US1005441A
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US1564446A
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US1818082A
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US2118060A
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US1913573A
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US2271131A
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US2456775A
Cited
GB684602A
Cited
US2820615A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-11-16 | 1963-05-18 | 1963-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-11-16 | 1967-05-18 | 1967-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-11-16 | 1971-05-18 | 1971-11-17 | $7700.00 | Window Closed / Lapsed |