Patent US3420212A successfully refreshed from Google Patents.
US3420212A
Expired / Lapsed
US
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Circuit for a regenerative preheating
Assignee: Hitachi Zosen Inova Steinmueller GmbH
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Filing: 1967-03-27
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Granted: 1969-01-07
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Expires: 1987-03-27
Abstract
No abstract record available.
Inventors
- 👤 Klaus Knizia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:28
CPC Classifications
F; F01; F01K; F01K7/00; F01K7/34; F01K7/40
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-01-07 | 1972-07-08 | 1973-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-01-07 | 1976-07-08 | 1977-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-01-07 | 1980-07-08 | 1981-01-07 | $7700.00 | Window Closed / Lapsed |