SCREENING APPARATUS FOR PAPERMAKING PULP

摘要

A hydrodynamic device for generating negative pressure excursions in a pulp slurry during fine screening, includes a plurality of half-foil members (123) disposed on a substantially cylindrical outer surface of a rotor (121). The rotor (121) is mounted within and co-axial with a substantially cylindrical screen (95) having a circumferentially continuous apertured zone to define an annular screening chamber (93) between the rotor (121) and the screen (95). The half-foil members (123) are collectively at least axially co-extensive with the apertured zone and have a leading edge which, also collectively, is inclined at a spiral angle relative to the axis of the rotor such that during rotation, the collective leading edge of the half-foil members conduct large particles downwardly through the screening chamber. A selection of hydrodynamic foil configurations is provided in order to adapt to a wide range of pulp types and screening conditions.