US2681705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shutoff apparatus for dual production wells
Assignee: Shell Development Co
•
Filing: 1951-06-05
•
Granted: 1954-06-22
•
Expires: 1971-06-05
Abstract
No abstract record available.
Inventors
- 👤 Ronald A Tappmeyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:27
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/14
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2277380A
Cited
US2403987A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-06-21 | 1957-12-21 | 1958-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-06-21 | 1961-12-21 | 1962-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-06-21 | 1965-12-21 | 1966-06-22 | $7700.00 | Window Closed / Lapsed |