Patent US3470971A successfully refreshed from Google Patents.
US3470971A
Expired / Lapsed
US
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Apparatus and method for automatically controlling fluid pressure in a well bore
Assignee: Warren Automatic Tool Co
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Filing: 1967-04-28
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Granted: 1969-10-07
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Expires: 1987-04-28
Abstract
No abstract record available.
Inventors
- 👤 Ethell J Dower
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:49
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/08; G; G05; G05D; G05D16/00; G05D16/024; G05D16/20; G05D16/2006; G05D16/2066
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1310615A
Cited
USRE26220E
Cited
US2884132A
Cited
US3219107A
Cited
US3260308A
Cited
US3318319A
Cited
US3362487A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-10-06 | 1973-04-07 | 1973-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-10-06 | 1977-04-07 | 1977-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-10-06 | 1981-04-07 | 1981-10-07 | $7700.00 | Window Closed / Lapsed |