Electrokinetic pump having capacitive electrodes

• US 7,875,159 B2
• Filed: 03/09/2007
• Issued: 01/25/2011
• Est. Priority Date: 10/18/2002
• Status: Expired due to Fees

• Current Assignee: Teleflex Life Sciences Pte., Ltd. (Teleflex Incorporated)
• Original Assignee: Eksigent Technologies LLC
• Inventors: Neyer, David W., Anex, Deon S., Paul, Phillip H.
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US11/684,500
• Publication Number:
  US 20070144909A1
• Time in Patent Office: 1,418 Days
• Field of Search: 204/450, 204/600, 417/48
• US Class Current: 204/450
• 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. A method of moving a liquid using an electrokinetic device comprising a pair of electrodes capable of having a voltage drop therebetween and a porous dielectric material between the electrodes, wherein the electrodes are comprised of a material having a capacitance of at least 10⁻

4 Farads per square centimeter, comprising the steps of;

(a) applying a positive current to the electrodes to charge the capacitance of the electrodes and to move the liquid through the porous dielectric material in a first direction;

(b) reversing the current applied to the electrodes prior to reaching a threshold voltage for a Faradaic process in the liquid; and

(c) applying a negative current to the electrodes to move the liquid through the porous dielectric material in a second direction that is opposite to the first direction.

2. The method of claim 1 wherein applying a negative current to the electrodes stops prior to the occurrence of a Faradaic process in the liquid.

3. The method of claim 1 wherein the liquid moves through the porous dielectric material at a rate of at least 1 mL/min.

4. The method of claim 1, further comprising:

after applying a negative current, reversing the current applied to the electrodes prior to reaching a threshold voltage for a Faradaic process in the liquid.

5. The method of claim 1, wherein moving a liquid through the porous dielectric material is the motive force in an indirect pumping system.

6. The method of claim 5 wherein the indirect pumping system is part of any one of:

a glucose monitor system, a drug delivery system or a liquid dispensing system.

7. The method of claim 1 further comprising:

stopping the applying a positive current step when a predetermined amount of a second liquid has been moved in a second device, wherein the second device is in communication with the liquid moved through the porous dielectric material.

8. The method of claim 7 wherein the second device is any one of:

a glucose monitoring device, a drug delivery device or a liquid dispensing device.

9. The method of claim 7 wherein the second liquid is either insulin or a drug.

10. A method of pumping a liquid through a porous dielectric material containing the liquid, comprising:

(a) applying a positive current to a pair of electrodes, wherein the electrodes sandwich the porous dielectric material and the capacitance of the electrodes is at least 10<sup>−

4</sup> Farads/cm², such that the liquid is pumped through the porous dielectric material in a first direction;

(b) stopping the applying a positive current to the pair of electrodes step before reaching a voltage drop across the electrodes that exceeds the threshold voltage for a Faradaic electrochemical reaction in the liquid; and

(c) applying a negative current to the electrodes such that the liquid is pumped through the porous dielectric material in a second direction, the second direction opposite the first.

11. The method of claim 10 further comprising:

stopping the applying a negative current to the pair of electrodes step before reaching a voltage drop across the electrodes that exceeds the threshold voltage for a Faradaic electrochemical reaction in the liquid.

12. The method of claim 10 wherein the steps are performed until a predetermined amount of liquid has been pumped.