Filter chambers composed of two adjacent filter disks are attached to a drum-like filtrate collection chamber and are adapted to rotate therewith. The filtrate penetrates the filter disks and enters the collection chamber and thereafter exits the collection chamber through a collection space. The collection space is sealed from the trough by means of a rotating seal. The suspension inlet is provided on a sidewall of the trough and the suspension outlet is provided on the opposite wall of the trough. The disk concentrator serves to remove filtrate from aqueous suspensions containing fibrous components.