Electrokinetic Pump Having Capacitive Electrodes

• US 20080173545A1
• Filed: 06/21/2007
• Published: 07/24/2008
• Est. Priority Date: 10/18/2002
• Status: Abandoned Application

• Current Assignee: Teleflex Life Sciences Pte., Ltd. (Teleflex Incorporated)
• Original Assignee: Eksigent Technologies LLC
• Inventors: Paul, Phillip H., Neyer, David W., Anex, Deon S.
• Application Number:
  US11/766,678
• Publication Number:
  US 20080173545A1
• Time in Patent Office: Days
• US Class Current: 204/600
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 19/00 Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B1/00 - F04B17/00
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 43/043 Micropumps

Abstract

An electrokinetic pump achieves high and low flow rates without producing significant gaseous byproducts and without significant evolution of the pump fluid. A first feature of the pump is that the electrodes in the pump are capacitive with a capacitance of at least 10⁻⁴ Farads cm². A second feature of the pump is that it is configured to maximize the potential across the porous dielectric material. The pump can have either or both features.

Claims

1. In an electrokinetic device comprising a pair of electrodes capable of having a voltage drop therebetween and a porous dielectric material between the electrodes, the improvement comprising the electrodes, wherein the electrodes are comprised of a material having a capacitance of at least 10⁻

4 Farads per square centimeter.

2. The device of claim 1, wherein the capacitance is at least 10⁻

2 Farads per square centimeter.

3. The device of claim 1 wherein the electrodes are comprised of carbon.

4. The device of claim 1 wherein the electrodes are comprised of carbon paper impregnated with carbon aerogel.

5. The device of claim 1 wherein the electrodes are comprised of ruthenium oxide.

6. The device of claim 1 wherein the electrodes are comprised of a substantially solid redox couple.

7. The device of claim 1 wherein the electrodes are comprised of substantially solid redox material.

8. The device of claim 1 wherein the electrokinetic device is laminated.

9. The device of claim 1 wherein the capacitance is charged prior to the occurrence of Faradaic processes in a fluid.

10. The device of claim 1 wherein the device is capable of generating a fluid flow at a rate of at least 1 mL/min.

11. The device of claim 1, further comprising supports sandwiching the electrodes and the porous dielectric material so that when there is a current flux on the electrodes the current flux is substantially uniform.

12. The device of claim 11 wherein the supports and the porous dielectric material each have a flow resistance, the flow resistance of the support material being less than that of the porous dielectric material.

13. In an electrokinetic device comprising a pair of electrodes and a porous dielectric material between the electrodes, the improvement comprising the electrodes being sufficiently proximate to the porous dielectric material so that when there is a voltage drop between the electrodes, the voltage drop across the porous dielectric material is at least 10% of the voltage drop between the electrodes and wherein the electrokinetic device is capable of generating fluid flow at a rate of at least 1 mL/min.

14. The device of claim 13, wherein the voltage drop across the porous dielectric material is at least 50% of the voltage drop between the electrodes.

15. The device of claim 13, wherein the voltage drop across the porous dielectric material is at least 85% of the voltage drop between the electrodes.

16. The device of claim 13, further comprising a spacer between the porous dielectric material and the electrodes.

17. The device of claim 16, wherein the porous dielectric material and the spacer each have a flow resistance, the flow resistance of the spacer being less than that of the porous dielectric material.

18. The device of claim 13, wherein the electrodes and the porous dielectric material each have a flow resistance, the flow resistance of the electrodes being less than that of the porous dielectric material.

19. The device of claim 13, where the porous dielectric material is inorganic.

20. An electrokinetic pump system comprising:

(a) a first flow path;

(b) a second flow path, the second flow path being spaced apart from the first flow path; and

(c) an electrokinetic pump comprising;

(i) a first diaphragm in contact with the first flow path, the first diaphragm being flexible and impermeable;

(ii) a second diaphragm in contact with the second flow path, the second diaphragm being flexible, impermeable, and spaced-apart from the first diaphragm;

(iii) a pair of spaced apart electrodes having a capacitance of at least 10<sup>−

4</sup> Farads/cm² and being located between the diaphragms; and

(iv) a porous dielectric material located between the electrodes.

21-34. -34. (canceled)