US2749241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing semi-chemical pulp
Assignee: DEV TECNIQUE de la PATE A PAPI
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Filing: 1952-03-08
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Granted: 1956-06-05
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Expires: 1972-03-08
Abstract
No abstract record available.
Inventors
- 👤 Marpillero Paolo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:42
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
137 words
A PROCESS FOR THE PRODUCTION OF A SEMI-CHEMICAL PULP FROM COMMINUTED CELLULOSIC RAW MATERIAL IN THE FORM OF WOOD CHIPS AND SMALL PIECES OF PLANTS, COMPRISING DIGESTING SAID RAW MATERIAL IN AN ACID BISULFITE LIQUOR HAVING AN INITIAL PH OF 2.2 TO 5.0 AND CONTAINING PER TON OF DRY RAW MATERIAL AN AMOUNT OF SO2 BETWEEN ABOUT 60 TO 120KG. PER TON OF DRY RAW MATERIAL WHICH IS INSUFFICIENT TO REMOVE ALL OF THE LIGNIN IN THE RAW MATERIAL, SAID DIFGESTING TAKING PLACE AT COOKING TEMPERATURES NOT SUBSTANTIALLY EXCEEDING 137* C. AND UNTIL AT LEAST A MAJOR PART OF THE WEIGHT BUT NOT ALL OF THE LIGNIN IS REMOVED, SAID LIQUOR CONTAINING ABOUT 3.5 TO 11 TIMES AS MUCH LIQUID BY WEIGHT AS DRY RAW MATERIAL, AND MECHANICALLY DEFIBRATING THE DIGESTED RAW MATERIAL TO FORM SAID PULP.
Claim 2
Dependent Claim
137 words
A PROCESS FOR THE PRODUCTION OF A SEMI-CHEMICAL PULP FROM COMMINUTED CELLULOSIC RAW MATERIAL IN THE FORM OF WOOD CHIPS AND SMALL PIECES OF PLANTS, COMPRISING DIGESTING SAID RAW MATERIAL IN AN ACID BISULFITE LIQUOR HAVING AN INITIAL PH OF 2.2 TO 5.0 AND CONTAINING PER TON OF DRY RAW MATERIAL AN AMOUNT OF SO2 BETWEEN ABOUT 60 TO 120KG. PER TON OF DRY RAW MATERIAL WHICH IS INSUFFICIENT TO REMOVE ALL OF THE LIGNIN IN THE RAW MATERIAL, SAID DIFGESTING TAKING PLACE AT COOKING TEMPERATURES NOT SUBSTANTIALLY EXCEEDING 137* C. AND UNTIL AT LEAST A MAJOR PART OF THE WEIGHT BUT NOT ALL OF THE LIGNIN IS REMOVED, SAID LIQUOR CONTAINING ABOUT 3.5 TO 11 TIMES AS MUCH LIQUID BY WEIGHT AS DRY RAW MATERIAL, AND MECHANICALLY DEFIBRATING THE DIGESTED RAW MATERIAL TO FORM SAID 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) | 1959-06-05 | 1959-12-05 | 1960-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-06-05 | 1963-12-05 | 1964-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-06-05 | 1967-12-05 | 1968-06-05 | $7700.00 | Window Closed / Lapsed |