# US 8,715,480 B2 · Electrokinetic pump having capacitive electrodes

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- Number: US 8,715,480 B2
- Document ID: US8715480B2
- Status: Granted
- Kind: B2
- Application number: 13/462,634
- Filed: 2012-05-02
- Published: 2012-08-30
- Granted: 2014-05-06
- Earliest claimed: 2002-10-18
- Assignees: Eksigent Technologies, LLC
- Applicants: Deon S. Anex; Phillip H. Paul; David W. Neyer
- Inventors: Deon S. Anex; Phillip H. Paul; David W. Neyer
- Web page: https://patentgrep.com/patent/US8715480B2

## 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 engine comprising:
a pair of porous capacitive electrodes;
a dielectric material sandwiched between the pair of capacitive electrodes; and
a pump fluid;
wherein a width of the electrokinetic engine in a first direction is greater than a thickness of the electrokinetic engine in a second direction, and wherein the porous capacitive electrodes and the dielectric material are in a flow-through configuration such that, during operation of the electrokinetic engine, the pump fluid flows in the second direction through both of the electrodes and the dielectric material.

### Claim 2 (depends on 1)

The electrokinetic engine of claim 1, wherein the electrokinetic engine is in approximately the shape of a coin.

### Claim 3 (depends on 1)

The electrokinetic engine of claim 1, wherein each of the capacitive electrodes directly contacts the dielectric material.

### Claim 4 (depends on 1)

The electrokinetic engine of claim 1, wherein a voltage drop across the dielectric material is at least 50% of a voltage drop between the pair of capacitive electrodes when voltage is applied to the electrodes from a power supply.

### Claim 5 (depends on 1)

The electrokinetic engine of claim 1, wherein at least 25% of the total area of each of the capacitive electrodes is open.

### Claim 6 (depends on 1)

The electrokinetic engine of claim 1, further comprising a pair of supports sandwiching the pair of capacitive electrodes and dielectric material therebetween, the supports configured to maintain approximate planarity of the electrokinetic engine.

### Claim 7 (depends on 1)

The electrokinetic engine of claim 1, wherein at least one of the capacitive electrodes has a width in the first direction approximately equal to a width of the dielectric material in the first direction.

### Claim 8 (depends on 1)

The electrokinetic engine of claim 1, wherein each of the capacitive electrodes has a double-layer capacitance of at least 10−4 Farads/cm2.

### Claim 9 (depends on 1)

The electrokinetic engine of claim 1, wherein each of the capacitive electrodes and the dielectric have an approximately circular face perpendicular to the second direction.

### Claim 10

An electrokinetic system comprising:
an electrokinetic engine including a pair of electrodes, a dielectric material sandwiched between the pair of electrodes, and a pump fluid;
a power supply; and
a controller, the controller programmed to:
(a) apply current from the power supply to move the pump fluid through both of the electrodes and the dielectric material; and
(b) stop applying the current from the power supply before a solvent electrolysis process starts in the pump fluid.

### Claim 11 (depends on 10)

The electrokinetic system of claim 10, 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 10)

The electrokinetic system of claim 10, wherein each of the electrodes has a double-layer capacitance of at least 10−4 Farads/cm2.

### Claim 14 (depends on 10)

The electrokinetic system of claim 10, wherein a width of the electrokinetic engine in a first direction is greater than a thickness of the electrokinetic engine in a second direction, and wherein applying current from the power supply to move the liquid through the electrodes and the dielectric material comprises moving the pump fluid in the second direction.

### Claim 15 (depends on 10)

The electrokinetic system of claim 10, wherein each of the electrodes is porous.

### Claim 16 (depends on 10)

The electrokinetic engine of claim 10, wherein at least 25% of the total area of each of the electrodes is open.

### Claim 17 (depends on 10)

The electrokinetic engine of claim 10, wherein at least one of the electrodes has a diameter approximately equal to a diameter of the dielectric material.

### Claim 18 (depends on 10)

The electrokinetic engine of claim 10, wherein the electrokinetic engine is in approximately the shape of a coin.

### Claim 19 (depends on 10)

The electrokinetic engine of claim 10, wherein each of the electrodes directly contacts the dielectric material.