A first feed comprising particulate material predominantly in the size range 30 mesh to 1/2 in. is fed into an upper portion of an upwardly extending casing, and is a major portion of the particulate material. A second feed, which is a minor portion of the particulate material, comprises at least 50%...http://www.google.es/patents/US4042353?utm_source=gb-gplus-sharePatente US4042353 - Method and apparatus for filtering through particulate material
Method and apparatus for filtering through particulate material
