Patent US2772138A successfully refreshed from Google Patents.
US2772138A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous bleaching process
Assignee: Hercules Powder Co
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Filing: 1952-12-31
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Granted: 1956-11-27
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Expires: 1972-12-31
Abstract
No abstract record available.
Inventors
- 👤 Forest B Evans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:35
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1026
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
153 words
THE METHOD FOR THE CONTINUOUS PURIFYING OF CELLULOSE FIBERS WHICH COMPRISES, IN COMBINATION, FORMING A DILUTE AQUEOUS SLURRY OF SAID FIBERS, CONTINUOUSLY PASSING AQUEOUS SLURRY AND CHLORINE GAS TO A LOWER PORTION OF A CONTACTING ZONE AND THEREIN CONTACTING SAID FIBERS AND CHLORINE IN A FIRST BLEACHING STEP, CONTINUOUSLY WITHDRAWING A SLURRY OF FIBERS AND BLEACH LIQUOR FROM AN UPPER PORTION OF SAID CONTACTING ZONE, CONTINUOUSLY PASSING WITHDRAWN SLURRY TO AN INCORPORATION ZONE, REMOVING BLEACH LIQUOR FROM SAID FIBERS IN SAID INCORPORATION ZONE AND RECYCLING REMOVED BLEACH LIQUOR TO SAID CONTACTING ZONE, IN SAID INCORPORATION ZONE WASHING REMAINING BLEACH LIQUOR FROM SAID FIBERS WITH WATER AND ADDING AN AQUEOUS SOLUTION OF A MEMBER OF THE GROUP CONSISTING OF BLEACHING AGENTS AND ALKALINE EXTRACTION AGENTS TO THE WASHED FIBERS IN AN AMOUNT IN EXCESS OF THE AMOUNT REQUIRED FOR THE SECOND REACTION STEP, IN SAID INCORPORATION ZONE REMOVING EXCESS AQUEOUS SOLUTION DILUTED WITH WASH
Claim 2
Independent Claim
153 words
THE METHOD FOR THE CONTINUOUS PURIFYING OF CELLULOSE FIBERS WHICH COMPRISES, IN COMBINATION, FORMING A DILUTE AQUEOUS SLURRY OF SAID FIBERS, CONTINUOUSLY PASSING AQUEOUS SLURRY AND CHLORINE GAS TO A LOWER PORTION OF A CONTACTING ZONE AND THEREIN CONTACTING SAID FIBERS AND CHLORINE IN A FIRST BLEACHING STEP, CONTINUOUSLY WITHDRAWING A SLURRY OF FIBERS AND BLEACH LIQUOR FROM AN UPPER PORTION OF SAID CONTACTING ZONE, CONTINUOUSLY PASSING WITHDRAWN SLURRY TO AN INCORPORATION ZONE, REMOVING BLEACH LIQUOR FROM SAID FIBERS IN SAID INCORPORATION ZONE AND RECYCLING REMOVED BLEACH LIQUOR TO SAID CONTACTING ZONE, IN SAID INCORPORATION ZONE WASHING REMAINING BLEACH LIQUOR FROM SAID FIBERS WITH WATER AND ADDING AN AQUEOUS SOLUTION OF A MEMBER OF THE GROUP CONSISTING OF BLEACHING AGENTS AND ALKALINE EXTRACTION AGENTS TO THE WASHED FIBERS IN AN AMOUNT IN EXCESS OF THE AMOUNT REQUIRED FOR THE SECOND REACTION STEP, IN SAID INCORPORATION ZONE REMOVING EXCESS AQUEOUS SOLUTION DILUTED WITH WASH
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) | 1959-11-27 | 1960-05-28 | 1960-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-11-27 | 1964-05-28 | 1964-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-11-27 | 1968-05-28 | 1968-11-27 | $7700.00 | Window Closed / Lapsed |