US2663549A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spiral heat exchanger
Assignee: Griscom Russell Co
•
Filing: 1950-07-14
•
Granted: 1953-12-22
•
Expires: 1970-07-14
Abstract
No abstract record available.
Inventors
- 👤 Philip S Otten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:24
CPC Classifications
F; F28; F28D; F28D9/00; F28D9/04; Y; Y10; Y10S; Y10S165/00; Y10S165/355; Y10S165/398
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US9690A
Cited
US2470860A
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US731469A
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US747072A
Cited
US1056932A
Cited
US1654294A
Cited
US1823481A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-12-21 | 1957-06-22 | 1957-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-12-21 | 1961-06-22 | 1961-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-12-21 | 1965-06-22 | 1965-12-22 | $7700.00 | Window Closed / Lapsed |