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Drifting Resonance Field (DRF) resonatorsSensors and Ultrasonics |
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[Sensors and Ultrasonics] [IAP-Homepage]
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Drifting Resonance Field (DRF) resonatorsSensors and Ultrasonics |
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Fig. 1 |
Ultrasonic particle separation techniques based upon coagulation
of the part
icles due to the Bernoulli force and the Secondary
radiation force (e.g. acoustic cell
retention systems) achieve their separation effect by trapping
the particles in the local maxima of acoustic displacement
velocity much the same way a conventional filter traps the
particles in a mechanical grid.
The Drifting Resonance Field (DRF) technique is an active separation method based upon the Primary radiation force providing the separate extraction of cleaned and particle en riched fluid. Ultrasonic resonators used for particle separation are driven at a high overtone. Driving the resonator cyclically at successive overtones yields a directed movement of the particles in specific regions (active volume)of the the resonator. This directed particle movement results in a spatial separation of particle enriched and cleaned fluid. The animation Fig. 1 demonstrates the DRF principle using the 4 overtones n=20 up to n=23. |
