US2679319A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for backflushing sectional filters
Assignee: Walker Process Equipment Inc
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Filing: 1951-12-20
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Granted: 1954-05-25
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Expires: 1971-12-20
Abstract
No abstract record available.
Inventors
- 👤 Walker James Donald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:42
CPC Classifications
B; B01; B01D; B01D24/00; B01D24/002; B01D24/005; B01D24/02; B01D24/20; B01D24/22; B01D24/46; B01D24/4631; B01D24/4642
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) | 1957-05-24 | 1957-11-23 | 1958-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-05-24 | 1961-11-23 | 1962-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-05-24 | 1965-11-23 | 1966-05-25 | $7700.00 | Window Closed / Lapsed |