Patent US2741536A successfully refreshed from Google Patents.
US2741536A
Expired / Lapsed
US
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Available chlorine multi-stage bleaching of sulfite pulp
Assignee: Olin Corp
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Filing: 1952-03-26
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Granted: 1956-04-10
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Expires: 1972-03-26
Abstract
No abstract record available.
Inventors
- 👤 William A Stone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:32
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/12; D21C9/14; D21C9/144
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
125 words
IN THE MULTI-STAGE PROCESS OF BLEACHING SULFITE CELLULOSE PULPS IN WHICH THE PULP TO BE BLEACHED IS SUBJECTED IN A PRELIMINARY STAGE TO A PARTIAL BLEACHING IN AQUEOUS MEDIUM AND UNDER ACID CONDITIONS IN WHICH ABOUT 50 TO 60 PER CENT OF THE CHLORINE REQUIREMENT OF THE PULP AS DETERMINED BY THE PERMANGANATE NUMBER IS SUPPLIED BY CHLORINE FOLLOWED BY A LATER STAGE OF BLEACHING WITH AN AQUEOUS SOLUTION OF HYPOCHLORITE, THE IMPROVEMENT WHICH COMPRISES PARTIALLY BLEACHING THE PULP IN THE PRELIMINARY STAGE IN AQUEOUS MEDIUM AND UNDER ACID CONDITIONS WITH CHLORINE DIOXIDE AND CHLORINE, THE AMOUNT OF THE CHLORINE REQUIREMENT SUPPLIED TO THE PRELIMINARY PARTIAL BLEACHING STAGE BY THE CHLORINE DIOXIDE BEING ABOUT 50 TO 75 PER CENT ON AN EQUIVALENT AVAILABLE CHLORINE BASIS.
Claim 2
Dependent Claim
125 words
IN THE MULTI-STAGE PROCESS OF BLEACHING SULFITE CELLULOSE PULPS IN WHICH THE PULP TO BE BLEACHED IS SUBJECTED IN A PRELIMINARY STAGE TO A PARTIAL BLEACHING IN AQUEOUS MEDIUM AND UNDER ACID CONDITIONS IN WHICH ABOUT 50 TO 60 PER CENT OF THE CHLORINE REQUIREMENT OF THE PULP AS DETERMINED BY THE PERMANGANATE NUMBER IS SUPPLIED BY CHLORINE FOLLOWED BY A LATER STAGE OF BLEACHING WITH AN AQUEOUS SOLUTION OF HYPOCHLORITE, THE IMPROVEMENT WHICH COMPRISES PARTIALLY BLEACHING THE PULP IN THE PRELIMINARY STAGE IN AQUEOUS MEDIUM AND UNDER ACID CONDITIONS WITH CHLORINE DIOXIDE AND CHLORINE, THE AMOUNT OF THE CHLORINE REQUIREMENT SUPPLIED TO THE PRELIMINARY PARTIAL BLEACHING STAGE BY THE CHLORINE DIOXIDE BEING ABOUT 50 TO 75 PER CENT ON AN EQUIVALENT AVAILABLE CHLORINE BASIS.
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) | 1959-04-10 | 1959-10-10 | 1960-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-04-10 | 1963-10-10 | 1964-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-04-10 | 1967-10-10 | 1968-04-10 | $7700.00 | Window Closed / Lapsed |