US3078208A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the production of neutral sulfite pulp
Assignee: Stora Enso Oyj
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Filing: 1959-09-10
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Granted: 1963-02-19
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Expires: 1979-09-10
Abstract
No abstract record available.
Inventors
- 👤 Cederquist Karl Nicolaus
- 👤 Eftring Karl Esbjorn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:28
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
105 words
A METHOD COMPRISING PREPARING SEMICHEMICAL NEUTRAL SULFITE PULP IN A YIELD OF AT LEAST ABOUT 80% AND TO A BRIGHTNESS OF AT LEAST 60 G.E. BY THE STEPS OF MAKING AN UNBUFFERED SOLUTION CONSISTING OF SODIUM SULFITE AND BISULFITE AND IN A PH RANGE OF 9.5 TO 6, THOROUGHLY STEAMING WOOD CHIPS, SUBSEQUENTLY IMPREGNATING SAID CHIPS WITH SAID SOLUTION AT A TEMPERATURE NO GREATER THAN ABOUT 110* C., REMOVING ALL FREE SOLUTION TO PROVIDE A DRY CONTENT OF AT LEAST 30%, DIGESTING THE CHIPS IN STEAM IN THE ABSENCE OF FREE SOLUTION AT A TEMPERATURE OF FROM 165 TO 175*C., AND DEFIBRATING THE RESULTING PULP.
Claim 2
Independent Claim
105 words
A METHOD COMPRISING PREPARING SEMICHEMICAL NEUTRAL SULFITE PULP IN A YIELD OF AT LEAST ABOUT 80% AND TO A BRIGHTNESS OF AT LEAST 60 G.E. BY THE STEPS OF MAKING AN UNBUFFERED SOLUTION CONSISTING OF SODIUM SULFITE AND BISULFITE AND IN A PH RANGE OF 9.5 TO 6, THOROUGHLY STEAMING WOOD CHIPS, SUBSEQUENTLY IMPREGNATING SAID CHIPS WITH SAID SOLUTION AT A TEMPERATURE NO GREATER THAN ABOUT 110* C., REMOVING ALL FREE SOLUTION TO PROVIDE A DRY CONTENT OF AT LEAST 30%, DIGESTING THE CHIPS IN STEAM IN THE ABSENCE OF FREE SOLUTION AT A TEMPERATURE OF FROM 165 TO 175*C., AND DEFIBRATING THE RESULTING PULP.
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) | 1966-02-18 | 1966-08-20 | 1967-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-02-18 | 1970-08-20 | 1971-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-02-18 | 1974-08-20 | 1975-02-19 | $7700.00 | Window Closed / Lapsed |