US2768822A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Regenerative air heater
Assignee: Individual
•
Filing: 1951-10-08
•
Granted: 1956-10-30
•
Expires: 1971-10-08
Abstract
No abstract record available.
Inventors
- 👤 Frey Kurt Paul Hermann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:52
CPC Classifications
C; C21; C21B; C21B9/00; F; F28; F28D; F28D17/00; F28D17/02; Y; Y10; Y10S; Y10S165/00; Y10S165/009; Y10S165/03; Y10S165/032; Y10S165/034
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1141108A
Cited
US1590373A
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US1724843A
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US1849657A
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US1944074A
Cited
FR806828A
Cited
US2181149A
Cited
US2479933A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-10-30 | 1960-04-30 | 1960-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-10-30 | 1964-04-30 | 1964-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-10-30 | 1968-04-30 | 1968-10-30 | $7700.00 | Window Closed / Lapsed |