US2428178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making finely divided volatilized silica
Assignee: Permanente Metals Corp
•
Filing: 1944-07-18
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Granted: 1947-09-30
•
Expires: 1964-07-18
Abstract
No abstract record available.
Inventors
- 👤 Reik Richard
- 👤 Alva C Byrns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:57
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/181; C01B33/182; C04; C04B; C04B35/00; C04B35/01; C04B35/14
Claims Analysis
Total Claims: 0
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US2272346A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-09-29 | 1951-03-31 | 1951-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-09-29 | 1955-03-31 | 1955-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-09-29 | 1959-03-31 | 1959-09-30 | $7700.00 | Window Closed / Lapsed |