| 摘要 |
Enhanced uniformity of treatment of the material with a treatment liquid in a continuous treatment vessel, is provided. The invention is particularly applicable to the treatment of comminuted cellulosic fibrous material to produce paper pulp, specifically for the digesting (kraft or sulfite, or solvent pulp processing) of wood chips to produce paper pulp. The vessel has at least one annular screen divided into at least four arcuate screen segments disposed around the internal periphery of the vessel, and a first liquid having treatment properties, and a second, spent liquid, are utilized in the treatment. A second liquid is withdrawn through at least a first of the arcuate screen segments while simultaneously the first liquid through or adjacent at least a second of the arcuate screen segments opposite the first screen segment. The various screen segments are operated, and at rest, in sequence to provide the uniformity of treatment. Introduction of liquid is preferably through slots or nozzles in land area between or adjacent the screen segments, rather than through the screen segments themselves, and liquid is continuously introduced through a central vertical pipe.
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