Separation of dispersed phases from liquids in acoustically driven chambers

Tolt, Thomas L.; Feke, Donald L.

doi:10.1016/0009-2509(93)80307-c

Cited by 67 publications

(32 citation statements)

References 14 publications

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“…16,17 Many acoustic sorting methods achieve particle or cell separation by either travelling waves 37,38 or by generating a standing wave field inside the active area of the device. 9,39,40 The difference in time-of-flight of particles due to the acoustic-viscous force balance has been utilized for continuous sorting first by the group of Feke 41,42 for size-based separation, followed by compressibility-based sorting of particles. 43 Increasing the frequency of the field, transducer dimensions and therefore the device size can be reduced and successful sorting can be achieved in microfluidic devices.…”

Section: Introductionmentioning

confidence: 99%

Particle separation by phase modulated surface acoustic waves

et al. 2017

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High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.

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Section: Introductionmentioning

confidence: 99%

Particle separation by phase modulated surface acoustic waves

et al. 2017

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“…Therefore, a one dimensional ultrasonic standing wave is formed when an appropriate gap between a transducer and reflector is maintained, so that the progressive wave and reflected wave can join at a suitable phase relation. At a certain point, anti-pressure node planes, which are vibrating inbetween ± maximum level from an equilibrium stage, are formed while pressure node planes are created of either the minimum level or 0 at locations 1/4 wavelength apart (Tolt and Feke, 1993). Particles which are relatively small as compared with the wavelength, when they are exposed to the ultrasonic standing wave, move to the pressure node or to the anti-pressure node.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, in relation to the frequency being used, Tolt and Feke (1993) have reported that the size of the ultrasonic radiation force was far larger than that of a progressive wave of the same energy density, and the radiation force was proportional to the drive frequency; a 0.3~1.5 MHz band was the optimal to use. Coakley (1997) has stated that it was desirable to use an ultrasonic wave of higher than 1 MHz to maintain high pressure, while cavitation, which is related to the formation of violently moving air bubbles, was not created.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Particle Separation in Suspension using an Ultrasonic Standing Wave

Shin

Danao

2012

Journal of Biosystems Engineering

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Purpose: Particle separation in solution is one of important process in a unit operation as well as in an extract preparation for biosensors. Contrary to centrifuge-type of mesh-type filter, using an ultrasonic standing wave make the filtering process continuous and free from maintenance. It is needed to investigate the characteristics of particle movement in the ultrasonic standing wave field. Methods: Through the computer simulation the effects of major design and driving parameters on the alignment characteristics of particles were investigated, and a cylindrical chamber with up-stream flow type was devised using two circular-shape PZTs on both sides of the chamber, one for transmitting ultrasonic wave and the other for just reflecting it. Then, the system performance was experimentally investigated as well. Results: The speed of a particle to reach pressure-node plane increased as the acoustic pressure and size of particle increased. The maximum allowable up-stream flow rate could be calculated as well. As expected, exact numbers of pressure-node planes were well formed at specific locations according to the wavelength of ultrasonic wave. As the driving frequency of PZT got close to its resonance frequency, the bands of particles were observed clearer, which meant the particles were trapped into narrower space. Higher excitation voltages to the PZT produced a greater acoustic force with which to trap particles in the pressure-node planes, so that the particles gathered could move upwards without disturbing their alignments even at a higher inlet flow rate. Conclusions: This research showed the feasibility of particle separation in solution in the continuous way by an ultrasonic standing wave. Further study is needed to develop a device to collect or harvest those separated particles.

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“…Ultrasonic aggregation has been exploited to improve the sensitivity of medical latex agglutination tests for detecting immunogenic agents (Grundy et al, 1994; Gualano et al, 19951, to fuse different cell types in combination with electric-field pulses (Vienken et al, 19851, and to enhance the recovery of two cell populations by phase partitioning (Allman and Coakley, 1994). The potential for continuous separation of particles from fluid suspensions was demonstrated by Tolt and Feke (1993). Continuous cell separation has been achieved for mammalian cells Correspondence concerning this article should be addressrd to S. M. Woodside.…”

mentioning

confidence: 98%

Acoustic force distribution in resonators for ultrasonic particle separation

et al. 1998

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The effectiveness of particle -liquid separation by ultrasonic radiation forces depends on the acoustic energy density distribution in the standing-wavefield. The energy distribution in an ultrasonic particle-separation device was analyzed to assist continued optimization and design efforts. Measurements of the energy-density distribution in the liquid using a microscope-based imaging system were compared to laser inteferometer measurements of the velocity-amplitude distribution on the transducer and rejlector sur- introductionThe capabilities of ultrasonic radiation forces for manipulating suspended particles have engendered a broad spectrum of experimental investigations. Ultrasonic aggregation has been exploited to improve the sensitivity of medical latex agglutination tests for detecting immunogenic agents (Grundy et al., 1994; Gualano et al., 19951, to fuse different cell types in combination with electric-field pulses (Vienken et al., 19851, and to enhance the recovery of two cell populations by phase partitioning (Allman and Coakley, 1994). The potential for continuous separation of particles from fluid suspensions was demonstrated by Tolt and Feke (1993). Continuous cell separation has been achieved for mammalian cells Correspondence concerning this article should be addressrd to S. M. Woodside. (Doblhoff-Dier et al., 1994; Trampler et al., 19941, yeast (Hawkes and Coakley, 1996), and bacteria (Hawkes et al., 1997). Fractionation according to particle size (Mandralis et al., 1994), continuous fractionation of mixed-particulate suspensions based on the compressibility of the solid phase (Gupta et al., 19951, and the selective retention of generally larger viable mammalian cells over nonviable cells and cell debris (Gaida et al., 1996) have been reported.Particle separation by ultrasonic forces exhibits innate advantages relative to conventional methods, particularly in the area of biotechnology. Cross-flow membrane filtration and spin-filter separators suffer from fouling; continuous centrifuges are susceptible to mechanical failure; conventional sedimentation systems require long holdup times. For ultrasonic separation, no physical barrier is required, there are no 1976September 1998 Vol. 44, No. 9 AIChE Journal moving mechanical parts, holdup times are low, and chemical flocculants are not necessary. Trampler et al. (1994) demonstrated the advantages of ultrasonic separation, running a continuous mammalian-cell perfusion culture for more than one month at cell concentrations up to 6X107/mL, with no decline in separation performance. In continuous separation systems, particles collect at the nodal planes of the standing-wave field due to the axial primary radiation force (PRF). Fluid flow is generally parallel to the nodal planes. The transverse PFR aggregates the particles within the nodal planes and retains them in the field against the flow-induced drag. The retention performance of these devices is therefore particularly dependent on the magnitude of the transverse PRF. The axial and transverse pri...

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Separation of dispersed phases from liquids in acoustically driven chambers

Cited by 67 publications

References 14 publications

Particle separation by phase modulated surface acoustic waves

Particle separation by phase modulated surface acoustic waves

Characteristics of Particle Separation in Suspension using an Ultrasonic Standing Wave

Acoustic force distribution in resonators for ultrasonic particle separation

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