MULTI-LAYERED PIEZOELECTRIC RESONATOR FOR THE SEPARATION OF SUSPENDED PARTICLES

摘要

Particulate material suspended in a fluid is separated and recycled by means of an ultrasonic resonance wave. In a preferred embodiment, the ultrasonic resonance field is generated within a multilayered co mposite resonator system including a transducer, the suspension and a mirror parallel to each other. Dimensions and frequencies reson ant to the whole system but not exciting Eigen-frequencies of transducer and mirror itself are chosen so that thermal dissipation is minimi zed. Generally, the process is suitable for all kinds of particles (solid, liquid or gaseous disperse phases) especially for hydrosols (p articles in water) and for separation of biological particles such as mammalian, bacterial and plant cells or aggregates. Specialized applica tions in biotechnology are described including an acoustic filter for mammalian cell bioreactors or the selective retention of viable cells relative to non-viable cells.