# US 8,192,604 B2 · Electrokinetic pump having capacitive electrodes

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- Number: US 8,192,604 B2
- Document ID: US8192604B2
- Status: Granted
- Kind: B2
- Application number: 13/013,484
- Filed: 2011-01-25
- Published: 2011-05-19
- Granted: 2012-06-05
- Earliest claimed: 2002-10-18
- Assignees: Eksigent Technologies, LLC
- Inventors: Deon S. Anex; Phillip H. Paul; David W. Neyer
- Web page: https://patentgrep.com/patent/US8192604B2

## CPC

- F04B 19/006: {Micropumps (F04B43/043 and F04B43/095 take precedence)}
- F04B 17/00: Pumps characterised by combination with, or adaptation to, specific driving engines or motors
- F04B 19/00: Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B1/00 - F04B17/00
- F04B 43/043: {Micropumps}
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)

## 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

### Claim 1

An electrokinetic system, comprising:
an electrokinetic device including a pair of electrodes, and a porous dielectric material between the electrodes, wherein each electrode of the pair of electrodes comprises a material having a capacitance of at least 10−4 Farads per square centimeter;
a liquid in the elecktrokinetic device between the pair of electrodes;
a power supply; and
a controller, the controller programmed to:
(a) apply a positive current from the power supply 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) stop applying the positive current applied by the power supply to the electrodes prior to reaching a threshold voltage for a Faradaic process in the liquid; and
(c) apply a negative current from the power supply to the electrodes to move the liquid through the porous dielectric material in a second direction that is opposite to the first directions.

### Claim 2 (depends on 1)

The electrokinetic system of claim 1, wherein the controller is further programmed to stop applying the negative current from the power supply to the electrodes prior to the occurrence of a Faradaic process in the liquid.

### Claim 3 (depends on 1)

The electrokinetic system of claim 1, wherein the electrodes do not generate gas and do not significantly alter the pH of the liquid.

### Claim 4 (depends on 1)

The electrokinetic system of claim 1, further comprising a reservoir including a working fluid, the working fluid in communication with the liquid.

### Claim 5 (depends on 4)

The electrokinetic system of claim 4, further comprising a flexible barrier separating the liquid from the working fluid, wherein the movement of the liquid causes the flexible barrier to flex to move the working fluid.

### Claim 6 (depends on 4)

The electrokinetic system of claim 4, wherein the working fluid is insulin or a drug.

### Claim 7 (depends on 4)

The electrokinetic system of claim 4, wherein the working fluid is part of a glucose monitoring system, a drug delivery system, or a fluid dispensing system.

### Claim 8 (depends on 4)

The electrokinetic system of claim 4, wherein the controller is further programmed to stop the applying, reversing, and applying steps when a predetermined amount of the working fluid has been moved.

### Claim 9

An electrokinetic system, comprising:
an electrokinetic device including a pair of electrodes, and a porous dielectric material between the electrodes, wherein each electrode of the pair of electrodes comprises a material having a capacitance of at least 10−4 Farads per square centimeter;
a liquid in the electrokinetic device between the pair of electrodes;
a power supply; and
a controller, the controller programmed to:
(a) apply a current from the power supply sufficient to move the liquid; and
(b) stop applying the current from the power supply before a solvent electrolysis process starts in the liquid.

### Claim 10 (depends on 9)

The electrokinetic system of claim 9, wherein the electrodes do not generate gas and do not significantly alter the pH of the liquid.

### Claim 11 (depends on 9)

The electrokinetic system of claim 9, further comprising a reservoir including a working fluid, the working fluid in communication with the liquid.

### Claim 12 (depends on 11)

The electrokinetic system of claim 11, further comprising a flexible barrier separating the liquid from the working fluid, wherein the movement of the liquid causes the flexible barrier to flex to move the working fluid.

### Claim 13 (depends on 11)

The electrokinetic system of claim 11, wherein the working fluid is insulin or a drug.

### Claim 14 (depends on 11)

The electrokinetic system of claim 11, wherein the working fluid is part of a glucose monitoring system, a drug delivery system, or a fluid dispensing system.