Patent US1555640A successfully refreshed from Google Patents.
US1555640A
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US
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Process for preparing alpha filtering material
Assignee: Individual
•
Filing: 1924-12-11
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Granted: 1925-09-29
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Expires: 1944-12-11
Abstract
No abstract record available.
Inventors
- 👤 Elizabeth E Day
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:20
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/02; B01J20/04; B01J20/041; B01J20/10; B01J20/12; B01J20/30; B01J20/3021; B01J2220/00; B01J2220/40; B01J2220/42
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) | 1928-09-28 | 1929-03-30 | 1929-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-09-28 | 1933-03-30 | 1933-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-09-28 | 1937-03-30 | 1937-09-29 | $7700.00 | Window Closed / Lapsed |