Patent US2571247A successfully refreshed from Google Patents.
US2571247A
Expired / Lapsed
US
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Electrodialytic treatment of well-drilling fluids
Assignee: NL Industries Inc
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Filing: 1943-09-06
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Granted: 1951-10-16
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Expires: 1963-09-06
Abstract
No abstract record available.
Inventors
- 👤 Earl E Huebotter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:26
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/42; B01D61/422; E; E21; E21B; E21B21/00; E21B21/06; E21B21/063; B01D2311/00; B01D2311/18
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) | 1954-10-15 | 1955-04-16 | 1955-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-10-15 | 1959-04-16 | 1959-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-10-15 | 1963-04-16 | 1963-10-16 | $7700.00 | Window Closed / Lapsed |