US2643645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Horizontal flue boiler with combustion preheater
Assignee: Individual
•
Filing: 1952-02-23
•
Granted: 1953-06-30
•
Expires: 1972-02-23
Abstract
No abstract record available.
Inventors
- 👤 Kleinen Theodor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:40
CPC Classifications
F; F22; F22B; F22B9/00; F22B9/10; F22B9/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US112761A
Cited
US833642A
Cited
US2146565A
Cited
GB473255A
Cited
US2141238A
Cited
US2220486A
Cited
US2354932A
Cited
US2554092A
Cited
US2368467A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-29 | 1956-12-29 | 1957-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-29 | 1960-12-29 | 1961-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-29 | 1964-12-29 | 1965-06-30 | $7700.00 | Window Closed / Lapsed |