US3262839A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Neutral to weakly alkaline sulfite process for the extraction of cellulose from cellulosic material
Assignee: GEA Group AG
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Filing: 1962-10-18
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Granted: 1966-07-26
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Expires: 1982-10-18
Abstract
No abstract record available.
Inventors
- 👤 Luthgens Manfred
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:13
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
112 words
IN THE PROCESS OF THE NEUTRAL TO WEAKLY ALKALINE SULFITE TYPE FOR EXTRACTING CELLULOSE FIBERS FROM WOOD, THE STEPS OF COMMINUTING THE WOOD TO WOOD CHIPS HAVING AN AVERAGE LENGTH OF ABOUT 15 MM. AND AN AVERAGE THICKNESS OF ABOUT 2 MM.; REMOVING AIR FROM SAID WOOD CHIPS; THROUGHLY IMPREGNATING THE RESULTANT AIR-FREED WOOD CHIPS WITH A SULFITE SOLUTION HAVING A PH VALUE BETWEEN 7 AND 11.5, SAID SULFITE SOLUTION HAVING A CONCENTRATION OF ABOUT 50 G./1. SODIUM SULFITE AND ABOUT 10 G./1. SODIUM SULFIDE, THE WEIGHT RATIO OF THE SULFITE SOLUTION TO THE WOOD CHIPS BEING ABOUT 5:1, RESPECTIVELY; AND DIGESTING THE RESULTANT IMPREGNATED WOOD CHIPS AT 200-280*C. FOR 5-30 MINUTES.
Claim 2
Dependent Claim
112 words
IN THE PROCESS OF THE NEUTRAL TO WEAKLY ALKALINE SULFITE TYPE FOR EXTRACTING CELLULOSE FIBERS FROM WOOD, THE STEPS OF COMMINUTING THE WOOD TO WOOD CHIPS HAVING AN AVERAGE LENGTH OF ABOUT 15 MM. AND AN AVERAGE THICKNESS OF ABOUT 2 MM.; REMOVING AIR FROM SAID WOOD CHIPS; THROUGHLY IMPREGNATING THE RESULTANT AIR-FREED WOOD CHIPS WITH A SULFITE SOLUTION HAVING A PH VALUE BETWEEN 7 AND 11.5, SAID SULFITE SOLUTION HAVING A CONCENTRATION OF ABOUT 50 G./1. SODIUM SULFITE AND ABOUT 10 G./1. SODIUM SULFIDE, THE WEIGHT RATIO OF THE SULFITE SOLUTION TO THE WOOD CHIPS BEING ABOUT 5:1, RESPECTIVELY; AND DIGESTING THE RESULTANT IMPREGNATED WOOD CHIPS AT 200-280*C. FOR 5-30 MINUTES.
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) | 1969-07-25 | 1970-01-24 | 1970-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-07-25 | 1974-01-24 | 1974-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-07-25 | 1978-01-24 | 1978-07-26 | $7700.00 | Window Closed / Lapsed |