摘要 |
In the continuous cooking of comminuted cellulosic fibrous material (e.g. wood chips) to produce paper pulp, the material passes upwardly in an impregnation vessel (34) which is within and concentric with a continuous digester (32) and open at the top to digester pressure. At the top of the impregnation vessel, a solids/liquid separator (36) (a screw (37) within a screen cylinder (38)) is provided. Separated liquid is returned in a conduit (41) adjacent the exterior of the impregnation vessel, and open at the top to digester pressure, and passes out the bottom of the digester. The impregnation vessel is welded to the bottom (35) of the digester, and the bottom of the digester is generally hemi-spherical, and substantially devoid of packings. |