Patent US3425558A successfully refreshed from Google Patents.
US3425558A
Expired / Lapsed
US
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Backwash means for dual filter elements
Assignee: Universal Filters Inc
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Filing: 1967-08-21
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Granted: 1969-02-04
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Expires: 1987-08-21
Abstract
No abstract record available.
Inventors
- 👤 Nils O Rosaen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:19
CPC Classifications
B; B01; B01D; B01D36/00; B01D36/02; B01D29/00; B01D29/01; B01D29/014; B01D29/05; B01D29/07; B01D29/071; B01D29/11; B01D29/114; B01D29/13; B01D29/15; B01D29/21; B01D29/50; B01D29/52; B01D29/54; B01D29/60; B01D29/606; B01D29/62; B01D29/64; B01D29/6438; B01D29/6446; B01D29/66; B01D29/663; B01D29/665; B01D29/70; B01D29/88; B01D29/94; B01D35/00; B01D35/14; B01D35/143; B01D35/147
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US280828A
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US550583A
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US2022016A
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US2077589A
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US2119433A
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US2362750A
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US3074556A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-02-04 | 1972-08-05 | 1973-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-02-04 | 1976-08-05 | 1977-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-02-04 | 1980-08-05 | 1981-02-04 | $7700.00 | Window Closed / Lapsed |