The diffusion dryer unit DDU 570/H is used for drying aerosols generated from an aqueous suspension or solution. The diffusion dryer is used downstream of the aerosol generator. The Diffusion Dryer DDU 570 has been developed mainly as additional equipment for the aerosol Generators produced by Topas GmbH. The diffusion dryer consists of an Acryl tube with 2 caps on its ends and tube connectors. In the operation status the dryer is filled with Silica gel. The aerosol to be dried is streaming through 3 screen pipes which are surrounded by Silica Gel (with indicator) serving as drying agent. The Silica gel causes a very dry atmosphere. The water in the aerosol moves into the dry environment by the effect of diffusion. Because the aerosol does not get into direct contact with the drying agent only a very low particle loss occurs.