Abstract

A device for separating fine articles as sand from a sludge containing ultrafine articles comprises a continuously rotated substantially horizontal drum having a helical web at the peripheral inside thereof. The mass flow to be separated is deposited in the drum at a place spaced from both ends of the drum. The drum moves the sand at the bottom of the drum to the discharge end thereof, where a water feeding system is arranged providing an oppositely directed fresh water flow which mixes with said ultrafine particles forming a sludge. The sand is elevated at the discharge end of the drum by a plurality of buckets and discharged via an inclined discharge chute through an outlet opening of the drum. The sludge is discharged through the opposite front wall opening through which the mass flow is fed within a feeding tube.