Patent US3297997A successfully refreshed from Google Patents.
US2264518A
Expired / Lapsed
US
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Valve operating means for duplex double-acting steam pumps
Assignee: Emsco Derrick and Equipment Co
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Filing: 1941-01-24
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Granted: 1941-12-02
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Expires: 1961-01-24
Abstract
No abstract record available.
Inventors
- 👤 Ralph L Foster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:37
CPC Classifications
F; F01; F01L; F01L23/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1944-12-01 | 1945-06-02 | 1945-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-12-01 | 1949-06-02 | 1949-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-12-01 | 1953-06-02 | 1953-12-02 | $7700.00 | Window Closed / Lapsed |