Patent US1951981A successfully refreshed from Google Patents.
Patent US2807451A successfully refreshed from Google Patents.
US2807451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Columns for contacting liquids with gases or vapours
Assignee: Individual
•
Filing: 1953-11-24
•
Granted: 1957-09-24
•
Expires: 1973-11-24
Abstract
No abstract record available.
Inventors
- 👤 Kuhni-Rietmann Margrit
- 👤 Fritz H Kuhni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:27
CPC Classifications
B; B01; B01D; B01D3/00; B01D3/14; B01D3/32; B01D3/324; B01D3/328; B01D3/16; B01D3/22
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1320210A
Cited
US657548A
Cited
GB140552A
Cited
US2011186A
Cited
US2241114A
Cited
FR891411A
Cited
US2645607A
Cited
US2619336A
Cited
GB690798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-09-23 | 1961-03-25 | 1961-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-09-23 | 1965-03-25 | 1965-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-09-23 | 1969-03-25 | 1969-09-24 | $7700.00 | Window Closed / Lapsed |