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US2371955A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well drilling fluid
Assignee: Shell Development Co
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Filing: 1943-08-31
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Granted: 1945-03-20
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Expires: 1963-08-31
Abstract
No abstract record available.
Inventors
- 👤 Reginald D Dawson
- 👤 Charles F Blankenhorn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:13
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/16
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) | 1948-03-19 | 1948-09-18 | 1949-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1952-03-19 | 1952-09-18 | 1953-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1956-03-19 | 1956-09-18 | 1957-03-20 | $7700.00 | Window Closed / Lapsed |