Patent US3225757A successfully refreshed from Google Patents.
US3225757A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiant tube heaters
Assignee: Hazen Engineering Co
•
Filing: 1962-11-09
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Granted: 1965-12-28
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Expires: 1982-11-09
Abstract
No abstract record available.
Inventors
- 👤 John D Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:08
CPC Classifications
F; F23; F23C; F23C3/00; F23C3/002
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1751533A
Cited
US2041312A
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US2051099A
Cited
GB502112A
Cited
GB539657A
Cited
US2479042A
Cited
US2415223A
Cited
US2602440A
Cited
AT208905B
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-12-27 | 1969-06-28 | 1969-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-12-27 | 1973-06-28 | 1973-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-12-27 | 1977-06-28 | 1977-12-28 | $7700.00 | Window Closed / Lapsed |