Patent US4121172A successfully refreshed from Google Patents.
US2779477A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter plant
Assignee: Norsk Hydro Elektrisk Kvaelstof AS
•
Filing: 1954-05-13
•
Granted: 1957-01-29
•
Expires: 1974-05-13
Abstract
No abstract record available.
Inventors
- 👤 Gunder G U W Swensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:55
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/62; B01D29/66; B01D29/11; B01D29/114; B01D29/50; B01D29/52; B01D29/60; B01D2201/00; B01D2201/04; B01D2201/0469; B01D2201/0476
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1214152A
Cited
US1263226A
Cited
US1452151A
Cited
US1870381A
Cited
US2046770A
Cited
US2035592A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-01-29 | 1960-07-30 | 1961-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-01-29 | 1964-07-30 | 1965-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-01-29 | 1968-07-30 | 1969-01-29 | $7700.00 | Window Closed / Lapsed |