Patent US2889931A successfully refreshed from Google Patents.
US2889931A
Expired / Lapsed
US
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Continuous rotary filter
Assignee: Phillips Petroleum Co
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Filing: 1954-12-27
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Granted: 1959-06-09
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Expires: 1974-12-27
Abstract
No abstract record available.
Inventors
- 👤 Doyle D Buttolph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:32
CPC Classifications
B; B01; B01D; B01D9/00; B01D9/0004; B01D9/0013; B01D33/00; B01D33/06; B01D33/073; B01D9/004; B01D9/0059; C; C07; C07C; C07C7/00; C07C7/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-06-08 | 1962-12-08 | 1963-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-06-08 | 1966-12-08 | 1967-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-06-08 | 1970-12-08 | 1971-06-09 | $7700.00 | Window Closed / Lapsed |