Abstract: Pulping apparatus for pulping high consistency paper pulp includes a tub having a bottom wall and a generally cylindrical side wall extending upwardly therefrom, and a rotor mounted centrally of the bottom wall for rotation about a vertical axis and having a hub portion, a plurality of vanes extending generally radially outwardly from the hub and having pumping and defibering faces thereon, and a plurality of helical screw flights extending upwardly from the hub. Each flight has a concave undersurface such that rotation of the rotor in the presence of high consistency pulp causes the screw flights to draw pulp inwardly toward the axis of rotation and push it downwardly to the defibering faces of the vanes, and the outer surface of each flight being convexly curved and of substantially greater surface are than its undersurface to provide an air foil effect further tending to draw pulp into the path of the undersurface of the following flight.

Abstract: A rotor for a pulper for liquid slurry stock includes a rotor body provided with circumferentially spaced composite vanes, each of which includes a defibering portion and a pumping portion. The defibering portion constitutes the outer end portion of each vane and is of relatively small axial dimensions. The pumping portion constitutes the upper portion of each composite vane and is of substantially greater axial dimensions with its upper surface of convex airfoil shape. The leading face of each pumping portion is essentially plane and inclined forwardly to overhang the trailing edge of the adjacent pumping portion and define therewith a groove in which the stock is channeled for forced centrifugally outward flow. In the preferred embodiment, the rotor cooperates with a frustoconical extraction plate, and the defibering vane portions have their undersurfaces inclined to match the inclination of the extraction plate and are proportioned to extend fully across the extraction plate.

Abstract: Recovery of paper fiber for reuse for waste paper materials containing plastic sheet and film is facilitated by the combination of a pulper in which the waste paper materials are pulped in a pulper equipped with a junk remover connected with the bottom of the pulper tub by a chute and provided with a pump constructed and arranged to maintain the hydrostatic head in the tub at a higher effective level than in the junk remover tower by circulating liquid from the tower back to the tub. The result is to cause transfer of the plastic and other lightweight trash to the junk remover for removal by its conveyor buckets and to prevent accumulation of lightweight trash in the tub to the extent that it interferes with extraction of the defibered paper slurry.