Patent US3003479A successfully refreshed from Google Patents.
US3003479A
Expired / Lapsed
US
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Steam and air boiler with heating surface of smallest load
Assignee: Duerrwerke AG
•
Filing: 1953-10-08
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Granted: 1961-10-10
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Expires: 1973-10-08
Abstract
No abstract record available.
Inventors
- 👤 Bock Peter
- 👤 Spies Hans
- 👤 Deitlhauser Karl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:56
CPC Classifications
F; F22; F22B; F22B35/00; F22B35/06; F22B35/14; Y; Y10; Y10S; Y10S122/00; Y10S122/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1770987A
Cited
US1890468A
Cited
US1927649A
Cited
US1973365A
Cited
US2334187A
Cited
US2366717A
Cited
GB566817A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-10-09 | 1965-04-10 | 1965-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-10-09 | 1969-04-10 | 1969-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-10-09 | 1973-04-10 | 1973-10-10 | $7700.00 | Window Closed / Lapsed |