New invention could replace industrial screens & mixers
13 Nov 2001
Scientists at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) are confident that their new Rotary Classifier will revolutionise the use of separator screens used in a large number of industrial applications.
'We believe that the fast, accurate particle classification possible with the Rotary Classifier makes it worth up to $100 million in the Australian market alone,' said the inventors of the Rotary Classifier, Drs Guy Metcalfe and Dr Kurt Liffman of CSIRO Thermal and Fluids Engineering.
'The Rotary Classifier overcomes the major problems of 'blinding' (where material jams the holes of the screen, effectively reducing the screen's operating surface), and constant wear-and-tear on screens from abrasive granular material,' added Dr Metcalfe.
The secret of the recently patented CSIRO Rotary Classifier is reportedly based on an observation that granular materials tumbled in a rotating vessel, segregate spontaneously depending on their size and density.
The vessel tumbles the particulate material, producing continuous or discrete avalanches in the surface. This action is said to move particles of smaller size or higher density towards the centre of the material and particles of larger size, or lower density, radially outward from the centre. Extraction of particulate material occurs at selected radial locations.
The device comprises a rotary longitudinal tube with a fixed endplate functioning as an output for the device, with holes for extracting particles from the tube. The holes are placed at different radial positions (or differently configured endplates are used) depending on the desired sizes of particulate material to be extracted. One, or several sized fractions can be removed simultaneously.
'The Rotary Classifier is more than just a separator screen. It has been designed to separate different materials, classify particles into groups by size or density, or it can be a highly effective mixer for different density materials such as wood and plastic which are inclined to layer rather than be evenly distributed during blending,' said Dr Metcalfe.
'Now that we have proved the Rotary Classifier, CSIRO Australia is looking for commercial partners who are in the industrial market and are interested in further development of the technology,' concluded Dr Metcalfe.
