Patent US2646678A successfully refreshed from Google Patents.
US2646678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling fluid filter loss tester
Assignee: California Research LLC
•
Filing: 1948-11-02
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Granted: 1953-07-28
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Expires: 1968-11-02
Abstract
No abstract record available.
Inventors
- 👤 Marshall B Standing
- 👤 Joseph F Chittum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:20
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/11; B01D29/111
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) | 1956-07-27 | 1957-01-26 | 1957-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-07-27 | 1961-01-26 | 1961-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-07-27 | 1965-01-26 | 1965-07-28 | $7700.00 | Window Closed / Lapsed |