Patent US2755168A successfully refreshed from Google Patents.
US2755168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods in the evaporation of liquors obtained in the digesting of cellulosic materials with alkali sulphite and/or alkali bisulphite
Assignee: Stora Enso Oyj
•
Filing: 1951-06-15
•
Granted: 1956-07-17
•
Expires: 1971-06-15
Abstract
No abstract record available.
Inventors
- 👤 Collin Per Harald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:13
CPC Classifications
D; D21; D21C; D21C11/00; D21C11/10; D21C11/106; Y; Y10; Y10S; Y10S423/00; Y10S423/03
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
110 words
IN A METHOD FOR THE RECOVERY OF ALKALI BY EVAPORATION OF THE LIQUOR OBTAINED FROM THE DIGESTION OF CELLULOSIC MATERIALS WITH AT LEAST ONE ALKALI SELECTED FROM THE GROUP CONSISTING OF ALKALI SULPHITE AND ALKALI BISULPHITE, THE IMPROVEMENT WHICH COMPRISES ADDING TO THE SAID LIQUOR, PRIOR TO THE EVAPORATION THEREOF, AN AMOUNT OF SODIUM SULPHATE CORRESPONDING FROM APPROXIMATELY 20% TO APPROXIMATELY 100% OF THE AMOUNT OF ALKALI LOST IN THE DIGESTION PROCESS, AND THEN SUBJECTING THE SAID LIQUOR TO PRESSURE AT A TEMPERATURE OF AT LEAST 120* C. TO PRECIPITATE A SUBSTANTIAL PROPORTION OF THE CALCIUM SULPHATE PRESENT IN THE LIQUOR, THEREBY PREVENTING INCRUSTATION DURING THE EVAPORATION OF SAID LIQUOR.
Claim 2
Dependent Claim
110 words
IN A METHOD FOR THE RECOVERY OF ALKALI BY EVAPORATION OF THE LIQUOR OBTAINED FROM THE DIGESTION OF CELLULOSIC MATERIALS WITH AT LEAST ONE ALKALI SELECTED FROM THE GROUP CONSISTING OF ALKALI SULPHITE AND ALKALI BISULPHITE, THE IMPROVEMENT WHICH COMPRISES ADDING TO THE SAID LIQUOR, PRIOR TO THE EVAPORATION THEREOF, AN AMOUNT OF SODIUM SULPHATE CORRESPONDING FROM APPROXIMATELY 20% TO APPROXIMATELY 100% OF THE AMOUNT OF ALKALI LOST IN THE DIGESTION PROCESS, AND THEN SUBJECTING THE SAID LIQUOR TO PRESSURE AT A TEMPERATURE OF AT LEAST 120* C. TO PRECIPITATE A SUBSTANTIAL PROPORTION OF THE CALCIUM SULPHATE PRESENT IN THE LIQUOR, THEREBY PREVENTING INCRUSTATION DURING THE EVAPORATION OF SAID LIQUOR.
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) | 1959-07-17 | 1960-01-16 | 1960-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-07-17 | 1964-01-16 | 1964-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-07-17 | 1968-01-16 | 1968-07-17 | $7700.00 | Window Closed / Lapsed |