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US2456831A
Expired / Lapsed
US
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Crystal seed and method of obtaining it
Assignee: Brush Development Co
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Filing: 1947-08-20
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Granted: 1948-12-21
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Expires: 1967-08-20
Abstract
No abstract record available.
Inventors
- 👤 Bengt R F Kjellgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:05
CPC Classifications
B; B01; B01D; B01D9/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1957299A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-12-21 | 1952-06-21 | 1952-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-12-21 | 1956-06-21 | 1956-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-12-21 | 1960-06-21 | 1960-12-21 | $7700.00 | Window Closed / Lapsed |