The invention relates to a device and to a method for the hydrodynamic removal of dense materials from a suspension, said device comprising a hydrocyclone (1), which holds the suspension, a classifying tube (2), which adjoins the hydrocyclone, and a storage chamber (3), which holds the removed dense materials, wherein a flushing water flow to the classifying tube (2) and a flushing water flow to the storage chamber (3) are provided, which can be controlled in a closed-loop or open-loop manner by means of a control element provided at the feed to the classifying tube and a control element provided at the feed to the storage chamber, respectively.