Patent US2454740A successfully refreshed from Google Patents.
US2454740A
Expired / Lapsed
US
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Apparatus for treating wells
Assignee: Dow Chemical Co
•
Filing: 1945-01-31
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Granted: 1948-11-23
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Expires: 1965-01-31
Abstract
No abstract record available.
Inventors
- 👤 Jr Philip J Lehnhard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:27
CPC Classifications
E; E21; E21B; E21B27/00; E21B27/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1385760A
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US1552675A
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US2168735A
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US2217857A
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US2171840A
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US2207345A
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US2274297A
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US2210205A
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US2330145A
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US2347589A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-11-23 | 1952-05-24 | 1952-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-11-23 | 1956-05-24 | 1956-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-11-23 | 1960-05-24 | 1960-11-23 | $7700.00 | Window Closed / Lapsed |