Clarifying thickener, and process operating therewith

The invention starts from a clarifying thickener for treating a suspension comprising a liquid and solids, to which suspension flocculents are added as required, the solids settling out from the liquid by sedimentation to form a sludge bed in the bottom region furnished with a rotatable rake mechanism (8) of the clarifying thickener constructed in the manner of a vessel, the outlet orifice (15, 16) of the suspension feed being arranged centrally to the vessel wall of the clarifying thickener beneath the sludge bed surface (10) and broadening outwards in a radial direction uniformly over its entire circumference in the outflow direction of the suspension. In order to ensure as uniform as possible and vortex-free distribution of the inflowing suspension in all radial directions and as complete as possible a separation of the solids from the suspension on flowing through the sludge bed, it is provided that the rake mechanism (8) having upwardly projecting rods, lugs or the like (22) engages in the space between the outlet orifice (15, 16) and the wall (17) of the clarifying thickener in the suspension stream moving radially outwards to equalize and dewater this suspension stream.