Patent US2235531A successfully refreshed from Google Patents.
US2235531A
Expired / Lapsed
US
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Method of producing paper filler
Assignee: West Virginia Pulp and Paper Co
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Filing: 1931-09-04
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Granted: 1941-03-18
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Expires: 1951-09-04
Abstract
No abstract record available.
Inventors
- 👤 Joseph E Plumstead
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 02:35
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/46; C01F11/464; C01F11/48; C09; C09C; C09C1/00; C09C1/02; C01P; C01P2006/00; C01P2006/60
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) | 1944-03-17 | 1944-09-16 | 1945-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-03-17 | 1948-09-16 | 1949-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-03-17 | 1952-09-16 | 1953-03-18 | $7700.00 | Window Closed / Lapsed |