US2801830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchange apparatus
Assignee: Foster Wheeler Inc
•
Filing: 1953-10-08
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Granted: 1957-08-06
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Expires: 1973-10-08
Abstract
No abstract record available.
Inventors
- 👤 Frisch Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:45
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/16; F28D7/163; F28D7/1638; F28D7/1646; F23; F23M; F23M20/00; Y; Y10; Y10S; Y10S165/00; Y10S165/921
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) | 1960-08-05 | 1961-02-04 | 1961-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-05 | 1965-02-04 | 1965-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-05 | 1969-02-04 | 1969-08-06 | $7700.00 | Window Closed / Lapsed |