Method and apparatus for separating particles (1) which are dispersed in a dispersion medium, whereby an ultrasonic standing wave (3) is generated by means of a composite resonator in a vessel (8) containing dispersion (2), the frequency of said wave preferably being in the neighborhood of the characteristic...http://www.google.es/patents/US5225089?utm_source=gb-gplus-sharePatente US5225089 - Method and apparatus for separating particles
