Vortex inducing rotor for screening apparatus for papermaking pulp

摘要

A rotor having a longitudinal axis of rotation and including an outer surface adjacent a screen surface. The rotor also includes a plurality of sets of radially extending, relative to the rotor axis, adjacent vane members attached to the rotor surface, each set including at least four adjacent vane members with equally spaced apart and parallel trailing edges ending in a common plane. The two outermost vane members have leading edges forward of the two most inside vane members, with the leading edges forward of the two most inside vane members being angled toward its next adjacent vane. The height of the two innermost vane members is about half of the height of the two outermost vane members. Each of the outermost vane members is angled relative to the circumferential direction of travel of the rotor by each of the outermost having vane members with a leading edge that is angled relative to its trailing edge. Each of the vane members has a leading edge forming an acute angle relative to the surface of the rotor and has a top edge with the same radius of curvature as the screen. The plurality of sets of vane members are spaced out throughout a screening chamber defined between the rotor surface and the screen in the direction of the rotor axis. The rotor outer surface does not have any longitudinally extending lifting bodies that produce pressure pulses throughout the screening chamber.