US2601667A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tube heater with flue gas recirculation and heating method
Assignee: Shell Development Co
•
Filing: 1948-02-12
•
Granted: 1952-06-24
•
Expires: 1968-02-12
Abstract
No abstract record available.
Inventors
- 👤 Permann Karl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:43
CPC Classifications
C; C10; C10G; C10G9/00; C10G9/14; C10G9/18; C10G9/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2224544A
Cited
US1083345A
Cited
US2081970A
Cited
US2114269A
Cited
US2348118A
Cited
US2395091A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-06-24 | 1955-12-24 | 1956-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-06-24 | 1959-12-24 | 1960-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-06-24 | 1963-12-24 | 1964-06-24 | $7700.00 | Window Closed / Lapsed |