Patent US4020054A successfully refreshed from Google Patents.
US2223027A
Expired / Lapsed
US
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Nonaqueous drilling fluid
Assignee: Shell Development Co
•
Filing: 1939-05-31
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Granted: 1940-11-26
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Expires: 1959-05-31
Abstract
No abstract record available.
Inventors
- 👤 Dawson Reginald David
- 👤 Huisman Philippus Henderikus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:43
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/32; Y; Y10; Y10S; Y10S507/00; Y10S507/91
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) | 1943-11-26 | 1944-05-27 | 1944-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-11-26 | 1948-05-27 | 1948-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-11-26 | 1952-05-27 | 1952-11-26 | $7700.00 | Window Closed / Lapsed |