Acoustophoresis device with dual acoustophoretic chamber
An acoustophoresis device includes an acoustic chamber with a piezoelectric element located within its volume. The piezoelectric element vibrates and generates acoustic standing waves from both sides, so that particles can be separated from fluid passing through the acoustic chamber. This permits the element to be cooled more efficiently, reducing transient heat loads in the fluid traveling through the device.
1. An acoustophoresis device, comprising:
a device inlet permitting fluid flow into the device;
a device outlet permitting fluid egress from the device; and
an acoustic chamber located in a fluid path between the device inlet and the device outlet, the acoustic chamber comprising:
a first ultrasonic transducer including a first face and a second face;
a first reflector opposite the first face of the first ultrasonic transducer, a first flow chamber being located between the first reflector and the first face of the first ultrasonic transducer; and
a second reflector opposite the second face of the first ultrasonic transducer, a second flow chamber being located between the second reflector and the second face of the first ultrasonic transducer;
wherein the first ultrasonic transducer is adapted to create a first multi-dimensional acoustic standing wave in the first flow chamber and a second multi-dimensional acoustic standing wave in the second flow chamber, and wherein secondary phase particles in a host fluid are trapped in the multi-dimensional acoustic standing waves and agglomerate into larger particles that continuously settle out at a critical particle size due to enhanced gravitational settling.
2. The acoustophoresis device of claim 1 , wherein the acoustic chamber further comprises: a holding plate that holds the first ultrasonic transducer, and two bracket plates having a slot for maintaining the holding plate in a fixed location in the acoustic chamber.
3. The acoustophoresis device of claim 1 , wherein the first ultrasonic transducer further comprises a piezoelectric element that includes a plurality of piezoelectric crystals.
4. The acoustophoresis device of claim 1 , wherein the first multi-dimensional acoustic standing wave has the same frequency as, or a different frequency from, the second multi-dimensional acoustic standing wave.
5. The acoustophoresis device of claim 1 , wherein the acoustophoresis device is shaped such that fluid flows into the device through the device inlet, into a first end of the acoustic chamber, then flows in parallel through the first flow chamber and the second flow chamber, out of the acoustic chamber through a second end of the acoustic chamber that is opposite the first end, and out of the device through the device outlet.
6. The acoustophoresis device of claim 1 , further comprising a contoured nozzle wall between the device inlet and the acoustic chamber.
7. The acoustophoresis device of claim 1 , wherein the acoustophoresis device is shaped such that fluid flows into the device through the device inlet, then travels through the acoustic chamber in a U-shaped path from a first end of the acoustic chamber to a second end through the first flow chamber and then back to the first end through the second flow chamber, then exits the flow chamber through the first end of the acoustic chamber and exits the device through the device outlet.
8. The acoustophoresis device of claim 7 , wherein the second end of the acoustic chamber leads to a well that tapers downwards in cross-sectional area from a single inlet to a vertex, and a drain line connecting the vertex to a port for recovering material collected in the well.
9. The acoustophoresis device of claim 1 , further comprising:
a second ultrasonic transducer including a first face and a second face, the first face of the second ultrasonic transducer facing the second reflector, and a third flow chamber being located between the second reflector and the first face of the second ultrasonic transducer; and
a third reflector opposite the second face of the second ultrasonic transducer, a fourth flow chamber being located between the third reflector and the second face of the second ultrasonic transducer.
10. A method of separating particles from a host fluid, comprising:
flowing a mixture of the host fluid and the particles through an acoustophoresis device that comprises:
a device inlet permitting fluid flow into the device;
a device outlet permitting fluid egress from the device; and
an acoustic chamber located in a fluid path between the device inlet and the device outlet, the acoustic chamber comprising:
a first ultrasonic transducer including a first face and a second face;
a first reflector opposite the first face of the first ultrasonic transducer, a first flow chamber being located between the first reflector and the first face of the first ultrasonic transducer; and
a second reflector opposite the second face of the first ultrasonic transducer, a second flow chamber being located between the second reflector and the second face of the first ultrasonic transducer; and
applying a drive signal to drive the first ultrasonic transducer to create multidimensional acoustic standing waves in the first flow chamber and the second flow chamber to separate the particles from the host fluid;
wherein the first ultrasonic transducer creates a first multi-dimensional acoustic standing wave in the first flow chamber and a second multi-dimensional acoustic standing wave in the second flow chamber, and wherein the particles in the host fluid are trapped in the multi-dimensional acoustic standing waves and agglomerate into larger particles that continuously settle out at a critical particle size due to enhanced gravitational settling.
11. The method of claim 10 , wherein the multi-dimensional standing waves result in an acoustic radiation force having an axial force component and a lateral force component that are of the same order of magnitude, in both the first flow chamber and the second flow chamber.
12. The method of claim 10 , wherein the particles are Chinese hamster ovary (CHO) cells, NS0 hybridoma cells, baby hamster kidney (BHK) cells, or human cells.
13. The method of claim 10 , wherein the drive signal has a frequency of 500 kHz to 10 MHz.
14. The method of claim 10 , wherein the drive signal is driven with amplitude or frequency modulation start/stop capability to eliminate acoustic streaming.
15. The method of claim 10 , wherein the mixture of the host fluid and the particles has a Reynolds number of 1500 or less prior to entering the acoustic chamber.
16. The method of claim 10 , wherein the first multi-dimensional acoustic standing wave has the same frequency as, or a different frequency from, the second multi-dimensional acoustic standing wave.
17. The method of claim 10 , wherein the acoustophoresis device is shaped such that fluid flows into the device through the device inlet, into a first end of the acoustic chamber, then flows in parallel through the first flow chamber and the second flow chamber, out of the acoustic chamber through a second end of the acoustic chamber, and out of the device through the device outlet.
18. The method of claim 10 , wherein the acoustophoresis device is shaped such that fluid flows into the device through the device inlet, then travels through the acoustic chamber in a U-shaped path from a first end of the acoustic chamber to a second end of the acoustic chamber through the first flow chamber and then back to the first end through the second flow chamber, then exits the flow chamber through the first end of the acoustic chamber and exits the device through the device outlet.
19. An acoustophoresis device, comprising:
a device inlet permitting fluid flow into the device;
a device outlet permitting fluid egress from the device; and
an acoustic chamber located in a fluid path between the device inlet and the device outlet, the acoustic chamber comprising:
a plurality of piezoelectric elements each piezoelectric element including a first face and a second face; and
a plurality of reflectors;
wherein each piezoelectric element is located between two reflectors, and wherein each piezoelectric element is adapted to create a first multi-dimensional acoustic standing wave from the first face and a second multi-dimensional acoustic standing wave from the second face, and wherein secondary phase particles in a host fluid are trapped in the multi-dimensional acoustic standing waves and agglomerate into larger particles that continuously settle out at a critical particle size due to enhanced gravitational settling.
20. The acoustophoresis device of claim 1 , wherein the first face and the second face of the first ultrasonic transducer are both directly exposed to fluid flowing through the device.
21. The acoustophoresis device of claim 1 , wherein the first face of the first ultrasonic transducer and the second face of the first ultrasonic transducer each have a wear layer.
22. The acoustophoresis device of claim 1 , wherein the first ultrasonic transducer is made up of at least two piezoelectric crystals, wherein a first piezoelectric crystal forms the first face and a second piezoelectric crystal forms the second face.