Method and particle concentration device by acoustophoresis

A concentration of a process medium (1) containing micrometric particles dispersed in a fluid (3) by acoustophoresis characterized in that it comprises a continuous flow and a laminar flow of the medium (1) concentrating successively through n areas (5) concentration, an application in each zone (5) concentration, a natural resonant frequency of stationary acoustic field on the flow of the medium (1) concentrating so as to agglomerating the particles in the form of a plurality of strips (2), and a recovery from a first sub-medium comprising particles in the form of strips (2) to the output of the n areas (5) concentration, wherein the resonance frequency of the acoustic field transmitted in the nth zone (5a) concentration is higher than the resonance frequency of the acoustic field transmitted in the nth + 1 zone (5b) of concentration in order to agglomerate successively the particles in the form of strips (2) increasingly spaced. The field of the invention relates to the concentration and recovery of micron sized particles by acoustophoresis. More specifically, the acoustic wave used for the concentration of microalgae types of particles downstream of a bioreactor, or other immiscible particles in a fluid (3).