Patent ID: 8651732

Claim:
Stirring device for activated sludges with a hyperboloid-like stirring body ( 2 ) attached to a shaft ( 1 ), wherein a plurality of transport ribs ( 3 ) running towards its circumferential boundary (UM) is provided on an upper side (O) of the stirring body ( 2 ), wherein the transport ribs ( 3 ) are running inclined at least in sections with respect to a radial direction and wherein an inclination of the transport ribs ( 3 ) is selected in such a manner that, when the stirring body ( 2 ) rotates in a specified direction of rotation (R), a radial flow pointing away from the circumferential boundary (UM) is generated, characterized in that at least one propeller ( 6 ) is attached to the shaft ( 1 ) which propeller generates a flow (A) directed towards the upper side (O) of the stirring body ( 2 ) during a rotation of the stirring body ( 2 ) in the direction of rotation (R).