Patent US2633989A successfully refreshed from Google Patents.
US2633989A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable level skimmer
Assignee: —
•
Filing: —
•
Granted: 1953-04-07
•
Expires: 1970-04-07
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:05
CPC Classifications
B; B01; B01D; B01D21/00; B01D21/24; B01D21/2433; B01D21/18; B01D21/245
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1582715A
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US1450545A
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US1625592A
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US1843329A
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DE536259C
Cited
US1860819A
Cited
US2102575A
Cited
US2086730A
Cited
US2226974A
Cited
US2140059A
Cited
US2349972A
Cited
US2455338A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-04-06 | 1956-10-06 | 1957-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-04-06 | 1960-10-06 | 1961-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-04-06 | 1964-10-06 | 1965-04-07 | $7700.00 | Window Closed / Lapsed |