US3425557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Backwash means for dual filter elements
Assignee: Universal Filters Inc
•
Filing: 1966-04-04
•
Granted: 1969-02-04
•
Expires: 1986-04-04
Abstract
No abstract record available.
Inventors
- 👤 Nils O Rosaen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:42
CPC Classifications
B; B01; B01D; B01D36/00; B01D36/02; B01D29/00; B01D29/01; B01D29/014; B01D29/11; B01D29/114; B01D29/50; B01D29/52; B01D29/54; B01D29/60; B01D29/606; B01D29/62; B01D29/64; B01D29/6438; B01D29/6446; B01D29/66; B01D29/663; B01D29/70; B01D29/88; B01D29/94; B01D35/00; B01D35/14; B01D35/143; B01D35/147; B01D36/001
Claims Analysis
Total Claims: 0
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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 |