US3210237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bisulphite pulping of pine wood
Assignee: Officemax Inc
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Filing: 1963-04-15
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Granted: 1965-10-05
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Expires: 1983-04-15
Abstract
No abstract record available.
Inventors
- 👤 Elmo H Madison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:50
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06; D21C3/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
133 words
THE METHOD OF PREPARING PULP FROM PINE WOOD CHIPS COMPRISING CHARGING THE DIGESTER WITH PINE WOOD CHIPS, FLOODING THE DIGESTER WITH AN EXCESS OF MAGNESIUM BISULPHITE LIQUOR AT A TEMPERATURE OF ABOUT 70*C. TO ABOUT 110*C. AND HAVING A PH OF ABOUT 2.5 TO ABOUT 4.0 AND CONTAINING SUBSTANTIALLY EQUAL PARTS OF FREE SO2 AND COMBINED SO2, THE TEMPERATURE OF THE CHIPS NOT EXCEEDING ABOUT 110*C. DURING IMPREGNATION, WITHDRAWING THE EXCESS COOKING LIQUOR AND RAISING THE TEMPERATURE OF THE IMPREGNATED CHIPS TO ABOUT 163*C. FOR A PREDETERMINED TIME, HOLDING THE TEMPERATURE AT ABOUT 163*C. FOR A PREDETERMINED TIME AND THEN LOWERING THE TEMPERATURE TO ABOUT 153*C. ADDING SULPHURIC ACID AND CONTINUING THE COOK FOR A PREDETERMINED TIME OF ABOUT 10 MINUTES TO ABOUT 60 MINUTES WITH THE TEMPERATURE BEING IN EXCESS OF 150*C.
Claim 2
Independent Claim
133 words
THE METHOD OF PREPARING PULP FROM PINE WOOD CHIPS COMPRISING CHARGING THE DIGESTER WITH PINE WOOD CHIPS, FLOODING THE DIGESTER WITH AN EXCESS OF MAGNESIUM BISULPHITE LIQUOR AT A TEMPERATURE OF ABOUT 70*C. TO ABOUT 110*C. AND HAVING A PH OF ABOUT 2.5 TO ABOUT 4.0 AND CONTAINING SUBSTANTIALLY EQUAL PARTS OF FREE SO2 AND COMBINED SO2, THE TEMPERATURE OF THE CHIPS NOT EXCEEDING ABOUT 110*C. DURING IMPREGNATION, WITHDRAWING THE EXCESS COOKING LIQUOR AND RAISING THE TEMPERATURE OF THE IMPREGNATED CHIPS TO ABOUT 163*C. FOR A PREDETERMINED TIME, HOLDING THE TEMPERATURE AT ABOUT 163*C. FOR A PREDETERMINED TIME AND THEN LOWERING THE TEMPERATURE TO ABOUT 153*C. ADDING SULPHURIC ACID AND CONTINUING THE COOK FOR A PREDETERMINED TIME OF ABOUT 10 MINUTES TO ABOUT 60 MINUTES WITH THE TEMPERATURE BEING IN EXCESS OF 150*C.
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) | 1968-10-04 | 1969-04-05 | 1969-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-10-04 | 1973-04-05 | 1973-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-10-04 | 1977-04-05 | 1977-10-05 | $7700.00 | Window Closed / Lapsed |