Acoustophoretic separation technology using multi-dimensional standing waves

Patent metadata

Field	Value
Publication number	US-9228183-B2
Application number	US-201414557040-A
Country	US
Kind code	B2
Filing date	Dec 1, 2014
Priority date	Mar 15, 2012
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

A system having improved trapping force for acoustophoresis is described where the trapping force is improved by manipulation of the frequency of the ultrasonic transducer. The transducer includes a ceramic crystal. The crystal may be directly exposed to fluid flow. The crystal may be air backed, resulting in a higher Q factor.

First claim

The invention claimed is:

1. A method for continuously separating a second fluid or a particulate from a host fluid, comprising:
flowing a mixture of the host fluid and the second fluid or particulate through an apparatus, the apparatus comprising:
a flow chamber having at least one inlet and at least one outlet;
at least one ultrasonic transducer located on a wall of the flow chamber, the transducer including a piezoelectric material driven by a voltage signal to create a multi-dimensional standing wave in the flow chamber; and
a reflector located on the wall on the opposite side of the flow chamber from the at least one ultrasonic transducer; and

sending a voltage signal to drive the at least one ultrasonic transducer to create the multi-dimensional standing wave, such that the second fluid or particulate is continuously trapped in the standing wave, and then agglomerates, aggregates, clumps, or coalesces together, and subsequently rises or settles out of the host fluid due to buoyancy or gravity forces, and exits the flow chamber;
wherein the multi-dimensional standing wave results in an acoustic radiation force having an axial force component and a lateral force component that are of the same order of magnitude; and
wherein the ultrasonic transducer comprises:
a housing having a top end, a bottom end, and an interior volume; and
a crystal at the bottom end of the housing having an exposed exterior surface and an interior surface, the crystal being able to vibrate when driven by a voltage signal.

2. The method of claim 1 , wherein the particulate is Chinese hamster ovary (CHO) cells, NS0 hybridoma cells, baby hamster kidney (BHK) cells, or human cells.

3. The method of claim 1 , wherein greater than 90% of the particulate is separated from the host fluid on a volume basis.

4. The method of claim 1 , wherein a backing layer contacts the interior surface of the crystal, the backing layer being made of a substantially acoustically transparent material.

5. The method of claim 4 , wherein the substantially acoustically transparent material is balsa wood, cork, or foam.

6. The method of claim 4 , wherein the substantially acoustically transparent material has a thickness of up to 1 inch.

7. The method of claim 4 , wherein the substantially acoustically transparent material is in the form of a lattice.

8. The method of claim 1 , wherein an exterior surface of the crystal is covered by a wear surface material with a thickness of a half wavelength or less, the wear surface material being a urethane, epoxy, or silicone coating.

9. The method of claim 1 , wherein the crystal has no backing layer or wear layer.

10. The method of claim 1 , wherein the multi-dimensional standing wave traps particles in a low field having a linear velocity of from 0.1 millimeter/second to greater than 1 centimeter/second.

11. The method of claim 1 , wherein the piezoelectric material vibrates in a higher order mode shape.

12. The method of claim 1 , wherein the piezoelectric material vibrates to create a displacement profile having multiple maxima and minima.

13. The method of claim 1 , wherein the mixture flows vertically downwards, and the second fluid or particulate floats upward to a collection duct.

14. The method of claim 1 , wherein the mixture flows vertically upwards, and the second fluid or particulate sinks down to a collection duct.

15. The method of claim 1 , wherein the standing waves are normal to the vertical flow direction.

16. The method of claim 1 , wherein hot spots are generated that are located at a minimum of the acoustic radiation potential.

17. The method of claim 1 , wherein the voltage signal has a sinusoidal, square, sawtooth, triangle, or pulsed waveform.

18. The method of claim 1 , wherein the voltage signal has a frequency of 100 kHz to 10 MHz.

19. The method of claim 1 , wherein the voltage signal is driven with amplitude or frequency modulation start/stop capability to eliminate acoustic streaming.

20. The method of claim 1 , wherein the mixture of the host fluid and the second fluid or particulate has a Reynolds number of 1500 or less prior to entering the flow chamber.

21. The method of claim 1 , wherein the particulate has a size of from about 0.1 microns to about 300 microns.

22. The method of claim 1 , wherein the mixture of the host fluid and the second fluid or particulate flows through the flow chamber at a rate of at least 0.25 liters/hour.

23. A method of continuously separating a second fluid or a particulate from a host fluid, comprising:
flowing a mixture of the host fluid and the second fluid or particulate through an apparatus, the apparatus comprising:
a flow chamber having at least one inlet and at least one outlet;
at least one ultrasonic transducer located on a wall of the flow chamber, the transducer including a piezoelectric material driven by a voltage signal to create a multi-dimensional standing wave in the flow chamber; and
a reflector located on the wall on the opposite side of the flow chamber from the at least one ultrasonic transducer; and

sending a voltage signal to drive the at least one ultrasonic transducer to separate the second fluid or particulate from the host fluid;
wherein the multi-dimensional standing wave results in an acoustic radiation force having an axial force component and a lateral force component that are of the same order of magnitude; and
wherein the mixture flows from an apparatus inlet through an annular plenum and past a contoured nozzle wall prior to entering the flow chamber inlet.

24. The method of claim 23 , wherein the separated second fluid or particulate agglomerates, aggregates, clumps, or coalesces and then rises, and wherein the inflowing mixture is directed to flow past the rising second fluid or particulate by the contoured nozzle wall.

25. The method of claim 23 , wherein the mixture flows from the apparatus inlet through the annular plenum and past the contoured nozzle wall to generate large scale vortices at the entrance to a collection duct prior to entering the flow chamber inlet, thus enhancing separation of the second fluid or particulate from the host fluid.

26. The method of claim 23 , wherein the reflector has a non-planar surface.

27. The method of claim 23 , wherein the apparatus further comprises:
the apparatus inlet that leads to the annular plenum;
the contoured nozzle wall downstream of the apparatus inlet;
a collection duct surrounded by the annular plenum; and
a connecting duct joining the contoured nozzle wall to the flow chamber inlet.

28. The method of claim 23 , wherein the at least one outlet includes a first outlet whose output substantially comprises the host fluid containing expressed biomolecules and a second outlet whose output substantially comprises the second fluid or particulate that has been separated from the mixture, wherein the particulate is Chinese hamster ovary (CHO) cells, NS0 hybridoma cells, baby hamster kidney (BHK) cells, or human cells.

29. A method for continuously separating a second fluid or a particulate from a host fluid, comprising:
flowing a mixture of the host fluid and the second fluid or particulate through an apparatus, the apparatus comprising:
a flow chamber having at least one inlet and at least one outlet;
a contoured nozzle wall upstream of the flow chamber inlet;
at least one ul

Assignees

• Flodesign Sonics Inc

Inventors

• Lipkens Bart
• Dionne Jason
• Presz Jr Walter M
• Kennedy Iii Thomas J

Classifications

• B06B1/0644 Primary

  using a single piezoelectric element (B06B1/0688 takes precedence) · CPC title

• C12N13/00 Primary

  Treatment of microorganisms or enzymes with electrical or wave energy, e.g. magnetism, sonic waves · CPC title

• B01D17/044

  by changing the pressure · CPC title

• H01L41/053

  Electricity · mapped topic

• B01D21/28

  Mechanical auxiliary equipment for acceleration of sedimentation, e.g. by vibrators or the like · CPC title