Abstract: A centrifugal cleaner has a cleaning quotient greater than 0.5 and a rejects by weight performance value typically of less than 5% (e.g. less than 2%) for conventional paper pulp furnish. The tangential inlet nozzle to the side wall near the top of the cleaner body has a non-circular--preferably D-shaped--inlet opening so as to provide enhanced throughput. The cleaner body side wall includes an upper portion that is conical and extends past the top nozzle, a generally cylindrical center portion which significantly increases retention time within the cleaner, and a conical bottom portion in which a bottom nozzle is operatively disposed. The bottom nozzle has a rejects opening therein with a diameter that is about 25-45% (preferbly roughly 1/3) of the internal diameter of the side wall at the opening, and is about 25-45% (preferably roughly 1/3) of the internal diameter of the top nozzle.

Abstract: A high consistency pressure screen comprises a screen including a profiled inner surface and a rotor including a profiled outer surface rotating adjacent and spaced from the profiled screen to produce a positive-negative pulsation cycle of approximately 50%--50%.

Abstract: A screening apparatus comprises a pair of stationary concentric screens with a plurality of foils rotating therebetween and adjacent thereto, the individual foils being radially aligned. The screening apparatus comprises a tangentially disposed slurry inlet and a diametrically and tangentially disposed heavy rejects outlet at the end of a heavy rejects trap. The light reject/accepts slurry flows into the screening zone and, after separation, is discharged at an end of the screening apparatus by way of respective light rejects and accepts outlets. The accept outlet is located axially with respect to the screen cylinders and rotating foils so the pressure pulses are virtually eliminated in the screening process. The apparatus may be constructed for vertical or horizontal rotation of the foils.

Abstract: A high consistency pressure screen comprises a screen including a profiled inner surface and a rotor including a profiled outer surface rotating adjacent and spaced from the profiled screen to produce a positive-negative pulsation cycle of approximately 50%--50%.

Abstract: A high consistency pressure screen comprises a screen including a profiled inner surface and a rotor including a profiled outer surface rotating adjacent and spaced from the profiled screen to produce a positive-negative pulsation cycle of approximatey 50%--50%.

Abstract: Apparatus for screening pulp slurry in an annular screening zone in the space between a screen of circular cross-section and a closed surface drum carrying pulse creating means, the screen and drum being coaxially mounted for relative rotation about their common axis, is characterized by means for feeding the slurry providing at least one inlet to the space extending substantially the full axial length of the screening zone, and means for removing from the space rejects not passing through the screen having at least one rejects outlet from the space extending substantially the full axial length of the screening zone.