Upgrading of recovered paper pulp - by hydrocyclonic separation of lighter adventitious matter e.g. plastic size

摘要

Hydrocyclone classifier for separating particles ligher than the fibres of an aqueous fibre suspension, partic. for the recovery of a papermaking pulp from waste paper, free from e.g. pieces of plastic, size, straw, string etc. comprising (a) a classifier chamber of circular cross section within a housing, at least partly conical, with a base (top) end and a tapering (bottom) end (b) =1 inlet at the base end for the tangential feed of liquid from outside the housing, to produce a liquid vortex stream in the classifier chamber extending from the base to the tapering end, so that the fibre component moves in the direction of the vortex periphery and the light particles towards the vortex core, (c) first and second outlets coaxial with the classifier chamber at the base and tapering ends respectively, from which flow liquid streams from the vortex core and periphery respectively. Enables the so-called 'reverse flow' classification to be carried out by using the hydro-cyclone under normal flow conditions, to separate components lighter than the main fibrous product.