US2882147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semi-chemical pulping process
Assignee: Monsanto Chemicals Ltd
•
Filing: 1956-03-12
•
Granted: 1959-04-14
•
Expires: 1976-03-12
Abstract
No abstract record available.
Inventors
- 👤 Charles H Davenport
- 👤 Burton E Helberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:09
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06; D21C3/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
144 words
A SEMI-CHEMICAL PROCESS FOR PRODUCING A BLEACHED WOOD PULP FROM MIXED HARDWOODS WHICH COMPRISES DIGESTING MIXED HARDWOOD CHIPS IN A DIGESTION LIQUOR COMPRISING FREE AMMONIA AS AMMONIUM HYDROXIDE AND COMBINED AMMONIA AS AMMONIUM SULFITE IN THE RATIO OF COMBINED TO FREE AMMONIA OF 3:1 TO 6:1, THE TOTAL AMMONIA COMPRISING ABOUT 10% BY WEIGHT BASED ON THE OVEN-DRY CHIPS BEING DIGESTED, SAID DIGESTION BEING CARRIED OUT AT A TEMPERATURE OF ABOUT 165-170* C.,. A PRESSURE OF 120130 POUNDS/SQ. IN. GUAGE, AND FOR A PERIOD OF ABOUT 4 HOURS, RECOVERING AMMONIA AND SULFUR VALUES FROM SAID DIGESTION LIQUOR, SUBJECTING SAID CHIPS AFTER SAID DIGESTION PERIOD TO AN AQUEOUS TREATMENT AT A TEMPERATURE NOT SUBSTANTIALLY ABOVE SAID DIGESTION TEMPERATURE, REFINING SAID CHIPS BY MECHANICAL ACTION AFTER SAID AQUEOUS TREATMENT UNTIL SAID CHIPS ARE REDUCED TO A FIBROUS PULP, AND TREATING SAID PULP WITH A BLEACHING AGENT.
Claim 2
Dependent Claim
144 words
A SEMI-CHEMICAL PROCESS FOR PRODUCING A BLEACHED WOOD PULP FROM MIXED HARDWOODS WHICH COMPRISES DIGESTING MIXED HARDWOOD CHIPS IN A DIGESTION LIQUOR COMPRISING FREE AMMONIA AS AMMONIUM HYDROXIDE AND COMBINED AMMONIA AS AMMONIUM SULFITE IN THE RATIO OF COMBINED TO FREE AMMONIA OF 3:1 TO 6:1, THE TOTAL AMMONIA COMPRISING ABOUT 10% BY WEIGHT BASED ON THE OVEN-DRY CHIPS BEING DIGESTED, SAID DIGESTION BEING CARRIED OUT AT A TEMPERATURE OF ABOUT 165-170* C.,. A PRESSURE OF 120130 POUNDS/SQ. IN. GUAGE, AND FOR A PERIOD OF ABOUT 4 HOURS, RECOVERING AMMONIA AND SULFUR VALUES FROM SAID DIGESTION LIQUOR, SUBJECTING SAID CHIPS AFTER SAID DIGESTION PERIOD TO AN AQUEOUS TREATMENT AT A TEMPERATURE NOT SUBSTANTIALLY ABOVE SAID DIGESTION TEMPERATURE, REFINING SAID CHIPS BY MECHANICAL ACTION AFTER SAID AQUEOUS TREATMENT UNTIL SAID CHIPS ARE REDUCED TO A FIBROUS PULP, AND TREATING SAID PULP WITH A BLEACHING AGENT.
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) | 1962-04-13 | 1962-10-13 | 1963-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-04-13 | 1966-10-13 | 1967-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-04-13 | 1970-10-13 | 1971-04-14 | $7700.00 | Window Closed / Lapsed |