Patent US2657247A successfully refreshed from Google Patents.
US2657247A
Expired / Lapsed
US
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High-temperature electric furnace and process of operation
Assignee: Evonik Operations GmbH
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Filing: 1950-10-05
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Granted: 1953-10-27
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Expires: 1970-10-05
Abstract
No abstract record available.
Inventors
- 👤 Bretschneider Otto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:56
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/62
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1132684A
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US1091808A
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US1147703A
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US1352086A
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US1456891A
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US1432505A
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US1557074A
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US1572881A
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US1553379A
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US2476916A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-10-26 | 1957-04-27 | 1957-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-10-26 | 1961-04-27 | 1961-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-10-26 | 1965-04-27 | 1965-10-27 | $7700.00 | Window Closed / Lapsed |