Tramp material separator

Abstract

Effective separation of unwanted particles, such as tramp material, is effected from a paper pulp suspension (typically a medium consistency suspension, e.g. having a consistency between 5-15 percent). A generally annular opening is defined by a disc connected to a rotating shaft, and a ring stationarily mounted to a housing. The housing includes a pulp inlet, a pulp outlet, an inlet chamber, and an outlet chamber, with a separated-out particles outlet communicating with the inlet chamber, preferably extending downwardly from it. A rotating element having a plurality of generally radially extending projections, is also mounted on the shaft, adjacent the disc, and the projections cover the annular opening (radially spanning it) at spaced locations along its circumference. The projections may be teeth-like structures, or pegs, and preferably have their leading edges, viewed in the direction of rotation, sloping with respect to the radial direction. A plurality of vanes are also connected to the shaft in the outlet chamber. The shaft rotates at such a speed that fluidization of the pulp by the rotating element takes place. Not only are particles having their largest dimension equal to or greater than the radial dimension of the annular opening separated-out, but also particles that are considerably smaller than that.