US3698995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digestion and bleaching of wood pulp followed by recovery of chemicals and countercurrent flow of wash water
Assignee: Tenneco Canada Inc
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Filing: 1971-02-22
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Granted: 1972-10-17
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Expires: 1991-02-22
Abstract
Abstract DIGESTING WOOD IN A PULPING LIQUOR FOLLOWED BY WASHING, BLEACHING, AND EXTRACTING OF THE PULP, AND CONCENTRATING AND SUBJECTING THE LIQUOR TO REDUCING CONDITIONS TO RECOVER CHEMICALS, WHEREIN AT LEAST PART OF THE WASH WATER OBTAINED FROM WASHING BLEACHED CELLULOSIC PULP OR FROM WASHING BLEACHED AND EXTRACTED CELLULOSIC PULP IN EMPLOYED TO WASH UNBLEACHED CELLULOSIC PULP THEREBY PROVIDING COUNTERCURRENT FLOW OF WASH WATER.
Inventors
- 👤 William H Rapson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:57
CPC Classifications
D; D21; D21C; D21C11/00; D21C11/0021; D21C11/0028; D21C9/00; D21C9/10; D21C9/12; D21C9/14; D21C9/142; Y; Y10; Y10S; Y10S162/00; Y10S162/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |