Hydraulic density separation device for separating a heavy material fraction with components of higher density from a light material fraction with components of lower density from a feed material , comprising - a conveying device for conveying away the heavy material fraction , - a receiving chamber which can be filled with water for receiving the feed material , - a flow generator for generating a water flow in the receiving chamber and - a water-fillable separation chamber for receiving the light material fraction , wherein the conveying device has a shaft with at least one screw conveyor section for conveying the heavy material fraction out of the receiving chamber , and wherein the flow generator is designed and arranged such that a flow path of the water flow leads from the receiving chamber into the separation chamber , wherein the conveying device has, in addition to the screw conveyor section , at least one washing section having a plurality of separate paddles arranged on the shaft , characterized in that a plurality of screw conveyor section is provided, wherein a washing section is arranged between two adjacent screw conveyor section and wherein a plurality of washing sections is provided, wherein the screw conveyor section and the washing sections are arranged alternately to one another, the paddles are arranged at an angle to the shaft in such a way that the heavy material fraction is also transported in the direction of the conveying direction (F) of the shaft in the area of the respective washing section , and a plurality of paddles are arranged one behind the other in relation to the longitudinal direction (L) of the shaft , and wherein a plurality of paddles is arranged one behind the other in the circumferential direction of the shaft . - a conveying device for conveying away the heavy material fraction , - a receiving chamber which can be filled with water for receiving the feed material , - a flow generator for generating a water flow in the receiving chamber and - a water-fillable separation chamber for receiving the light material fraction , wherein the conveying device has a shaft with at least one screw conveyor section for conveying the heavy material fraction out of the receiving chamber , and wherein the flow generator is designed and arranged such that a flow path of the water flow leads from the receiving chamber into the separation chamber , wherein the conveying device has, in addition to the screw conveyor section , at least one washing section having a plurality of separate paddles arranged on the shaft , characterized in that a plurality of screw conveyor section is provided, wherein a washing section is arranged between two adjacent screw conveyor section and wherein a plurality of washing sections is provided, wherein the screw conveyor section and the washing sections are arranged alternately to one another, the paddles are arranged at an angle to the shaft in such a way that the heavy material fraction is also transported in the direction of the conveying direction (F) of the shaft in the area of the respective washing section , and a plurality of paddles are arranged one behind the other in relation to the longitudinal direction (L) of the shaft , and wherein a plurality of paddles is arranged one behind the other in the circumferential direction of the shaft . <EOS>