US3811994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of continuous cellulose digestion and digester adapted for performing the method
Assignee: Metso Fiber Karlstad AB
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Filing: 1971-06-29
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Granted: 1974-05-21
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Expires: 1991-06-29
Abstract
Abstract IN A CONTINUOUS CELLULOSE DIGESTER IMPREGNATION OF CHIPS WITH DIGESTING LIQUOR TAKES PLACE IN A TOP ZONE AND DIGESTION TAKES PLACE IN A LOWER ZONE. A COMPARATIVELY LOW TEMPERATURE IS MAINTAINED OVER AT LEAST THE GREATER PART OF THE IMPREGNATING ZONE BY PREVENTING HEATED LIQUOR FROM THE DIGESTING ZONE TO ENTER THE IMPREGNATING ZONE DUE TO THE CONVECTION, IN A TRANSITION ZONE COOLED LIQUID IS BROUGHT TO FLOW RADIALLY AND HORIZONTALLY OVER THE ENTIRE CROSS-SECTION OF THE CHIPS COLUMN IN ORDER TO SEPARATE THE TWO ZONES IN TEMPERATURE RESPECTS.
Inventors
- 👤 B Ostberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:11
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/22; D21C3/24; D21C7/00
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |