Siegfried Ripperger and Lars Steinke, Technische Universität Kaiserslautern, Germany, developed a new method for the classification of suspensions by means of rotating filter discs.

The classification without a filter cake buildup by means of a single shaft disc filter is possible using the high-frequency autodynamic backwashing method.
The rotational velocity has an influence on the pressure on the inside of the disc. By adjusting the rotational velocity, the connection of the differential pressure between the outer disc area and the disc interior with the inclined position of the filter discs can be set up so that a periodic backwashing of the filter media takes place.

The scientists demonstrated that the separation of coarse particles is entirely possible.

• Classification of Suspensions by Means of Rotating Filter Discs and Autodynamic High-Frequency Backwashing
  L. Steinke, S. Ripperger,
  Chem. Eng. Technol. 2010,
  DOI: 10.1002/ceat.201000150