PUMP

• US 20140050604A1
• Filed: 02/03/2012
• Published: 02/20/2014
• Est. Priority Date: 02/03/2011
• Status: Active Grant

• Current Assignee: TTP Ventus Limited
• Original Assignee: The Technology Partnership PLC (TTP Group Ltd.)
• Inventors: Buckland, Justin Rorke, Campbell, Andrew Robert
• Granted Patent: US 10,975,855 B2
• Time in Patent Office: Days
• US Class Current: 417/413.2
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 43/046 with piezoelectric drive
• CPC Class Codes: F04B 45/047 Pumps having electric drive
• CPC Class Codes: F04F 7/00 Pumps displacing fluids by using inertia thereof, e.g. by generating vibrations therein

Abstract

A pump comprising a side wall closed at each end by an end wall forming a cavity for, in use, containing a fluid, one or more actuators each operatively associated with one or more of the end walls to cause an oscillatory motion of the associated end wall(s) whereby, in use, these axial oscillations of the end wall(s) drive substantially radial oscillations of the fluid pressure in the cavity, two or more apertures in the cavity, a valve disposed in at least one of the apertures, wherein the actuator(s) is arranged to be non-axisymmetric in use such that, in use, a pressure oscillation with at least one nodal diameter is generated within the cavity.

Claims

1. A pump comprising:

a side wall closed at each end by an end wall forming a cavity for, in use, containing a fluid;

one or more actuators each operatively associated with one or more of the end walls to cause an oscillatory motion of the associated end wall(s) whereby, in use, these axial oscillations of the end wall(s) drive substantially radial oscillations of the fluid pressure in the cavity;

two or more apertures in the cavity;

a valve disposed in at least one of the apertures;

wherein the actuator(s) is arranged to be axially asymmetric in use such that, in use, a pressure oscillation with at least one nodal diameter is generated within the cavity.

2. A pump according to claim 1, wherein the actuator includes axially asymmetric features.

3. A pump according to claim 1, wherein the actuator includes a piezoelectric layer.

4. A pump according to claim 3, wherein the axial asymmetry is defined by sections of the piezoelectric layer having different polarisation.

5. A pump according to any one of claims 1 to 3, wherein the actuator includes at least two electrodes.

6. A pump according to claim 5, wherein the axial asymmetry is defined by separate electrodes and/or the absence of an electrode.

7. A pump according to claim 5, wherein at least one of the electrodes is non-coaxial relative to the actuator.

8. A pump according to claim 5, wherein a plurality of electrodes are provided in a regular pattern which is non-coaxial relative to the actuator.

9. A pump according to claim 1, wherein the actuator includes a piezoelectric layer which is non-coaxial relative to the cavity.

10. A pump according to any one of the preceding claims, further comprising an electrical drive circuit for generating one or more drive signals for supply to the actuator.

11. A pump according to claim 10, wherein the drive signal(s) cause generation of axially asymmetric motion of the actuator.

12. A pump according to any one of the preceding claims, wherein the actuator contains at least one elliptical element.

13. A pump according to any one of the preceding claims, wherein, in use, the actuator causes a pressure oscillation with a plurality of nodal diameters to be generated.

14. A pump according to any one of the preceding claims, wherein the end wall motion is mode-shape matched to the pressure oscillations in the cavity.

15. A pump according to any one of the preceding claims, wherein, in use, the frequency of the oscillatory motion is within 20% of a resonant frequency of the substantially radial pressure oscillations in the cavity.

16. A pump according to claim 15, wherein, in use, the frequency of the oscillatory motion is equal to a resonant frequency of the substantially radial pressure oscillations in the cavity.

17. A pump according to any one of the preceding claims, wherein the cavity is substantially circular or elliptical.

18. A pump according to any one of the preceding claims, wherein there are at least two apertures including at least one inlet aperture and at least one outlet aperture.

19. A pump according to claim 18, wherein, in use, the pressure oscillations of the fluid in the cavity cause fluid to flow from one or more of the inlet apertures to one or more of the outlet apertures.

20. A pump according to any one of the preceding claims, wherein, in use, the frequency of pressure oscillations in the cavity is greater than 500 Hz.

21. A pump according to claim 20, wherein, in use, the frequency of radial pressure oscillations in the cavity is greater than 19,000 Hz.

22. A pump according to any one of the preceding claims, wherein the ratio of the radius of the cavity (a) to the height of the side wall (h) is greater than 1.7.

23. A pump according to any one of the preceding claims, wherein the radius of the cavity (a) and the height of the side wall (h) satisfy the relationship

24. A pair of pumps according to any one of the preceding claims, wherein the two pump cavities are separated by a common end wall.

25. A pair of pumps according to claim 24, wherein the common cavity end wall is formed by an actuator.