US2421918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of producing aluminum oxide substantially free from silica
Assignee: MONOLITH PORTLAND MIDWEST Co
•
Filing: 1944-09-20
•
Granted: 1947-06-10
•
Expires: 1964-09-20
Abstract
No abstract record available.
Inventors
- 👤 Frank J Anderson
- 👤 Duncan R Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:45
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/04; C01F7/08
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1320172A
Cited
US1036454A
Cited
US1079899A
Cited
US1137860A
Cited
US1422004A
Cited
US1157436A
Cited
US1514657A
Cited
US1591365A
Cited
CH137204A
Cited
US1971354A
Cited
US1978823A
Cited
US2082526A
Cited
US2141132A
Cited
US2248826A
Cited
US2330631A
Cited
US2283849A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-06-09 | 1950-12-09 | 1951-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-06-09 | 1954-12-09 | 1955-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-06-09 | 1958-12-09 | 1959-06-10 | $7700.00 | Window Closed / Lapsed |