The production of definite nano particles is only given by the use of selected processes as well as fluids. These fluids and/or also mixing agents are often undesired in the later application. For this our system offers the possibility of multiple washing. The fluids, separated in the system, will be replaced by suitable washing liquids, and this process can be multiple repeated, as required. In a special processing form also a coating or consciously docking of materials with very special characteristics at the classified particles is possible.