US2242497A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of removing silica from minerals, slags, and similar materials
Assignee: WALTHER H DUISBERG
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Filing: 1939-04-03
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Granted: 1941-05-20
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Expires: 1959-04-03
Abstract
No abstract record available.
Inventors
- 👤 Zintl Eduard
- 👤 Krings Walter
- 👤 Brauning Wilhelm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:12
CPC Classifications
C; C01; C01G; C01G1/00; C01G1/02; C01P; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1944-05-19 | 1944-11-18 | 1945-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-05-19 | 1948-11-18 | 1949-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-05-19 | 1952-11-18 | 1953-05-20 | $7700.00 | Window Closed / Lapsed |