US2807325A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas operated well seal
Assignee: Houston Engineers Inc
•
Filing: 1954-12-27
•
Granted: 1957-09-24
•
Expires: 1974-12-27
Abstract
No abstract record available.
Inventors
- 👤 Derrel D Webb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:46
CPC Classifications
E; E21; E21B; E21B23/00; E21B23/06; E21B23/065
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) | 1960-09-23 | 1961-03-25 | 1961-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-09-23 | 1965-03-25 | 1965-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-09-23 | 1969-03-25 | 1969-09-24 | $7700.00 | Window Closed / Lapsed |