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US2907351A
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Means for protecting well casing from corrosion
Assignee: California Research LLC
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Filing: 1955-12-05
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Granted: 1959-10-06
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Expires: 1975-12-05
Abstract
No abstract record available.
Inventors
- 👤 Gilson H Rohrback
- 👤 John E Warren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:27
CPC Classifications
E; E21; E21B; E21B17/00; E21B41/00; E21B41/02; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49863; Y10T29/4987; Y10T29/53; Y10T29/53657
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) | 1962-10-05 | 1963-04-06 | 1963-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-10-05 | 1967-04-06 | 1967-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-10-05 | 1971-04-06 | 1971-10-06 | $7700.00 | Window Closed / Lapsed |