Abstract: The invention relates to a primary pulper turbine for processing recycled paper, of the type having the general shape of an helix.This turbine is formed of a shaft (2) carrying at least two helical disks (3, 4) coaxial to the shaft (2) and having a small pitch. These disks extend over at most 360.degree. and are spaced from each other along the shaft (2) by a distance of at least 1.5 times the helical pitch of a disk. The turbine carries on its base a set of radially extending fins (6, 7, 8), each one of which is curved into a spiral starting from the shaft (2).Preferably, the slant of the helical disks (3, 4, 5) relative to a plane perpendicular to the shaft (2) is approximately 15.degree., and the disks are angularly spaced from each other by a same angle approximately equal to 360.degree. divided by the number of disks, for providing a proper dynamic balance of the turbine.

Abstract: The invention relates to a method and apparatus for sorting out recycled paper pulp obtained from scrap material containing contaminants in the form of large pieces of foreign material such as plastics, adhesives, pieces of rope and the like.The invention avoids the need to disintegrate such large pieces of foreign material prior to their removal.The device of the invention comprises a drum (1) with an horizontal axis (2), an end wall (3) of the drum being fitted with a perforated plate (4) and an helical stirrer (5) having profiled blades rotating in a plane parallel to this plate at a short distance thereof, these blades having a transverse cross-section with a hydrodynamic profile adapted for generating a depression in front of the perforated plate, and a leading edge (6) forming a Bernouilli spiral with a constant angle of approximately 30.degree.

Abstract: A device for cleaning and recovering paper pulp includes a tank divided into inner and outer chambers by a fixed cylindrical sieve. The inner chamber also contains a rotating drum with blades that draw acceptable pulp from the outer chamber through the sieve to the inner chamber for discharge and moves rejected material through a helical path in the outer chamber toward another discharge point. The end of the helical path is blocked to form a dead space where the rejected material is concentrated and then periodically discharged.