Acoustic concentration of particles in fluid flow

• US 7,837,040 B2
• Filed: 04/09/2007
• Issued: 11/23/2010
• Est. Priority Date: 04/09/2007
• Status: Active Grant

• Current Assignee: TRIAD National Security, LLC
• Original Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Inventors: Kaduchak, Gregory, Ward, Michael D.
• Primary Examiner(s): Karmis; Stefanos
• Assistant Examiner(s): KUMAR, KALYANAVENKA K
• Application Number:
  US11/784,936
• Publication Number:
  US 20080245745A1
• Time in Patent Office: 1,324 Days
• Field of Search: 209/18, 209/210, 209/156, 209/590, 210/748
• US Class Current: 209/210
• CPC Class Codes: B01D 11/0261 comprising vibrating mechanisms, e.g. mechanical, acoustical
• CPC Class Codes: B01D 61/00 Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor separation of gases or vapours by diffusion B01D53/22
• CPC Class Codes: B07B 2230/04 The screen or the screened materials being subjected to ultrasonic vibration
• CPC Class Codes: C12M 47/02 Separating microorganisms from the culture medium; Concentration of biomass separating microorganisms from their culture media C12N1/02
• CPC Class Codes: G01N 1/4077 by other techniques involving separation of suspended solids
• CPC Class Codes: G01N 2001/4094 using ultrasound

Abstract

An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

Claims

1. An apparatus for acoustic concentration of particles in a fluid flow, comprising:

a flow channel;

a substantially acoustically transparent membrane disposed at a top surface of said flow channel;

a vibration generator, said vibration generator and said membrane defining a fluid flow path therebetween, said fluid flow path in fluid communication with a fluid source and a fluid outlet and having a predetermined dimension, said vibration generator disposed adjacent said fluid flow path and operable to produce an acoustic field in said fluid flow path, said acoustic field producing at least one pressure minima in said fluid flow path at a predetermined location within said fluid flow path, and

wherein the membrane is configured to reflect an acoustic wave generated by the vibration generator back into said fluid flow path, such that the reflected acoustic wave is out of phase with the acoustic wave generated by the vibration generator.

2. The apparatus of claim 1 wherein said membrane is formed from at least one material selected from the group consisting of Mylar®

, glass mica, polymers, and any combination thereof.

3. The apparatus of claim 1 wherein said predetermined location in said fluid flow path is adjacent a membrane wall.

4. The apparatus of claim 1 wherein said predetermined dimension is a function of the resonance of the fluid source.

5. The apparatus of claim 1 wherein said predetermined location is a function of a wavelength of said acoustic field produced by said vibration generator.

6. The apparatus of claim 4 wherein said predetermined location is ¼

of said wavelength of said acoustic field.

7. The apparatus of claim 4 wherein said predetermined location is 5/4 of said wavelength of said acoustic field.

8. The apparatus of claim 1 wherein said vibration generator is a piezoelectric transducer.

9. The apparatus of claim 1 wherein said predetermined particles are positive acoustic contrast particles.

10. The apparatus of claim 1 wherein said membrane is permeable.

11. The apparatus of claim 9 wherein reagents diffuse through said membrane to said predetermined particles in said flow path when flow is stopped in said flow path.

12. The apparatus of claim 1 further comprising a matching layer intermediate said vibration generator and said flow path.

13. The apparatus of claim 12 wherein said matching layer is a ¼

wavelength matching layer.

14. The apparatus of claim 1 wherein a wall of said membrane accommodates high power microscopic observation of said particles in said flow path.

15. The apparatus of claim 1 wherein said predetermined particles are particles selected from the group consisting of particles of different sizes and particles with different acoustic contrasts and wherein said apparatus performs field flow fractionation.

16. A method for concentrating and trapping particles in a fluid flow, comprising:

disposing a substantially acoustically transparent membrane at a top surface of a flow channel;

driving a vibration generator and producing an acoustic field, the acoustic field producing at least one pressure minima in the fluid flow path at a predetermined location and forcing predetermined particles in the fluid flow to the at least one pressure minima

wherein a flow path is defined between the vibration generator and the membrane, and the membrane is configured to reflect an acoustic wave generated in the fluid flow path by the vibration generator back into said fluid flow path, and wherein the reflected acoustic wave is out of phase with the acoustic wave generated by the vibration generator.

17. The method of claim 16 wherein the membrane is formed from at least one material selected from the group consisting of Mylar®

, glass mica, polymers, and a combination thereof.

18. The method of claim 16 wherein the predetermined dimension is a function of the resonance of the fluid source.

19. The method of claim 16 wherein the predetermined location is a function of a wavelength of the acoustic field produced by the vibration generator.

20. The method of claim 19 wherein the predetermined location is ¼

of the wavelength of the acoustic field.

21. The method of claim 19 wherein the predetermined location is 5/4 of the wavelength of the acoustic field.

22. The method of claim 16 wherein the vibration generator is a piezoelectric transducer.

23. The method of claim 16 wherein the predetermined particles are positive acoustic contrast particles.

24. The method of claim 16 wherein the membrane is permeable.

25. The method of claim 24 further comprising the step of diffusing reagents through the membrane to the predetermined particles in the flow path when flow is stopped in the flow path.

26. The method of claim 16 further comprising the step of providing a matching layer intermediate the vibration generator and the flow path.

27. The method of claim 26 wherein the matching layer is a ¼

wavelength matching layer.

28. The method of claim 16 further wherein a wall of the membrane accommodates high power microscopic observation of the particles in the flow path.

29. The method of claim 16 wherein the predetermined particles are particles selected from the group consisting of particles of different sizes and particles with different acoustic contrasts.

30. The method of claim 16 further comprising the step of performing field flow fractionation.

31. The method of claim 16 wherein the predetermined location is adjacent a membrane wall.