2.2. Pressure screen design

Pressure screening is nowadays the most widely used method for cleaning pulp, its success being based on the invention of profiled screen plates, which give better capacity per unit screening area than do smooth screen plates (Winkler & Kelly 1994). Pressure screens are also used for the fractionation of pulps, which can be considered to be a specific application of screening (Borschke et al. 1998).

There are several configurations for pressure screens devices. A design which corresponds closely to the principle employed in this work is illustrates in Fig. 1. This screen has an axial feed, a foil rotor with a conical rotor body, and a slotted screen plate.