Pulp and papermaking, pulp dewatering, pulping, straw pulp, bamboo and wood pulp, chemical pulp, cotton pulp, wood fiber, straw, bagasse, pulping plant, paper mill, pre-steaming, continuous reaction, cooking screw, pressing wood knots and sawdust, double-screw press, black liquor extraction. Suitable for the dewatering, concentration, washing, concentration, and black liquor extraction of chemical pulp, chemi-mechanical pulp, waste paper pulp, poplar chemi-mechanical pulp, eucalyptus chemi-mechanical pulp, bamboo, wood, and grass pulp residue fibers, reeds and other raw materials. Multiple units can be connected in series for better extraction effect. Mixed raw materials such as short fibers, bamboo fibers, wood fibers, and long fibers. All can meet the process requirements for reaction, washing, concentration and dewatering, and concentration enhancement. Pulp deinking, virgin fiber plant, sawdust, tobacco paper mill.