# US 7,267,753 B2 · Electrokinetic device having capacitive electrodes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,267,753 B2 - Document ID: US7267753B2 - Status: Granted - Kind: B2 - Application number: 10/322,083 - Filed: 2002-12-17 - Published: 2004-04-22 - Granted: 2007-09-11 - Earliest claimed: 2002-10-18 - Assignees: Eksigent Technologies, LLC - Inventors: Deon Anex; Phillip Paul; David W. Neyer - Web page: https://patentgrep.com/patent/US7267753B2 ## 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 device is capable of operating for extended periods of time, e.g. days to a week, without producing significant gaseous byproducts and without significant evolution of the pump fluid. Features of the electrokinetic device include: the electrodes in the electrokinetic device are capacitive with a capacitance of at least 10−4 Farads/cm2; at least part of the inner surfaces of the electrodes have an area greater than the effective area of the porous dielectric material; at least part of the inner surfaces of the electrodes have a current flux less than 20 microamperes/cm2; and at least part of the inner surfaces of the electrodes have a current flux that varies by less than a factor of two. The electrokinetic device can have one or several of these features in any combination. ## Claims ### Claim 1 An electrokinetic device comprising: (a) a pair of electrodes capable of having a voltage drop therebetween; (b) a porous dielectric material between the electrodes; and (c) a through-via in liquid communication with the porous dielectric material; wherein the electrodes are comprised of a material having a capacitance of at least 10−4 Farads per square centimeter and each electrode has an inner surface proximate to the porous dielectric material; and, wherein the electrodes are shaped so that the inner surfaces have a current flux of less than about 20 microamperes/cm2 over at least a portion of each inner surface. ### Claim 2 (depends on 1) The device of claim 1 wherein the electrodes have a current flux of less than about 2 microamperes/cm2 over at least a portion of each inner surface. ### Claim 3 An electrokinetic device comprising: (a) a pair of electrodes capable of having a voltage drop therebetween; (b) a porous dielectric material between the electrodes; and, (c) a through-via in liquid communication with the porous dielectric material; wherein the electrodes are comprised of a material having a capacitance of at least 10−4 Farads per square centimeter and each electrode has an inner surface proximate to the porous dielectric material, and, wherein the electrodes are shaped so that the inner surfaces have a current flux of less than about 20 microamperes per cm2 over an area of the inner surfaces greater than an effective area of the porous dielectric material. ### Claim 4 (depends on 3) The device of claim 3 wherein the electrodes have a current flux of less than about 2 microamperes/cm2 over an area of the inner surfaces greater than an effective area of the porous dielectric material. ### Claim 5 An electrokinetic device comprising: (a) a pair of electrodes having a voltage drop therebetween; (b) a porous dielectric material between the electrodes; and, (c) a through-via in liquid communication with the porous dielectric material; wherein the electrodes are comprised of a material having a capacitance of at least 10−4 Farads per square centimeter and each electrode has an inner surface proximate to the porous dielectric material and the inner surface has a current flux wherein the electrodes are shaped so that the current flux varies by less than a factor of two over at least a portion of each inner surface. ### Claim 6 (depends on 5) The device of claim 5 wherein the current flux varies by less than 20% over at least a portion of each inner surface. ### Claim 7 (depends on 5) The device of claim 5 wherein the current flux is less than about 20 microamperes/cm2 over at least a portion of each inner surface. ### Claim 8 An electrokinetic device comprising: (a) a pair of electrodes having a voltage drop therebetween; (b) a porous dielectric material between the electrodes; and, (c) a through-via in liquid communication with the porous dielectric material; wherein the electrodes are comprised of a material having a capacitance of at least 10−4 Farads per square centimeter and each electrode has an inner surface proximate to the porous dielectric material and the inner surface has a current flux wherein the electrodes are shaped so that the current flux varies by less than a factor of two over an area of the inner surfaces greater than an effective area of the porous dielectric material. ### Claim 9 (depends on 8) The device of claim 8 wherein the current flux is less than about 20 microamperes/cm2 over an area of the inner surface greater than an effective area of the porous dielectric material. ### Claim 10 An electrokinetic device comprising: (a) a pair of electrodes having a voltage drop therebetween; and, (b) 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 and each electrode has an inner surface proximate to the porous dielectric material and the inner surface has a current flux wherein the electrodes are shaped so that the current flux varies by less than a factor of two over an area of the inner surfaces greater than an effective area of the porous dielectric material wherein the device is capable of pumping a fluid unidirectionally for a period of time without causing significant electrolysis of the fluid. ### Claim 11 (depends on 10) The device of claim 10 wherein the period of time is at least one day. ### Claim 12 (depends on 11) The device of claim 11 wherein the period of time is at least six days. ### Claim 13 An electrokinetic device comprising; (a) a pair of electrodes having a voltage drop therebetween; (b) a porous dielectric material between the electrodes; and, (c) a through-via in liquid communication with the porous dielectric material; wherein the electrodes are comprised of a material having a capacitance of at least 10−4 Farads per square centimeter wherein the shape of the electrodes is substantially annular, spherical, hemispherical, strip-like, elliptical or cylindrical. ### Claim 14 (depends on 13) The device of claim 13 wherein the electrodes have an inner surface proximate to the porous dielectric material and the inner surface has a current flux of less than about 20 microamperes/cm2 over an area of the inner surface greater than an effective area of the porous dielectric material. ### Claim 15 (depends on 13) The device of claim 13 wherein each electrode has an inner surface proximate to the porous dielectric material and the inner surface has a current flux, wherein the current flux varies by less than a factor of two over an area of the inner surface greater than effective area of the porous dielectric material. ### Claim 16 (depends on 13) The device of claim 13 wherein the electrodes have an inner surface proximate to the porous dielectric material and the inner surface has a current flux of less than about 20 microampere s/cm2 over an area of the inner surface greater than an effective area of the porous dielectric material and wherein the current flux varies by less than a factor of two over an effective area of the porous dielectric material. ### Claim 17 An electrokinetic device comprising: (a) a pair of capacitive electrodes capable of having a voltage drop therebetween; (b) a pair of sensor electrodes; and, (c) a porous dielectric material located between the capacitive electrodes and between the sensor electrodes; wherein the sensor electrodes are attached to an apparatus for measuring the voltage drop across the porous dielectric material. ### Claim 18 (depends on 17) The device of claim 17 further comprising a power supply operatively attached to the capacitive electrodes, wherein the measuring apparatus outputs the voltage drop across the porous dielectric material into the power supply and wherein the power supply adjusts the voltage drop across the porous dielectric material so that fluid moves through the porous dielectric material at a desired rate. ### Claim 19 An electrokinetic device comprising: (a) a substrate having a first and a second through-via; (b) a porous dielectric material located inside the substrate and being in liquid communication with the through-vias; (c) a first capacitive electrode located on the substrate adjacent to the first through-via, the first capacitive electrode having an inner surface proximate to the first through-via; and, (d) a second capacitive electrode located on the substrate adjacent to the second through-via, the second capacitive electrode having an inner surface proximate to the second through-via; wherein each inner surface has a current flux and wherein the electrodes are shaped so that the current flux varies by less than a factor of two over an area of the inner surfaces greater than an effective area of the porous dielectric material and wherein the current flux is less than about 20 microamperes/cm2 over an area of the inner surfaces greater than an effective area of the porous dielectric material. ### Claim 20 An electrokinetic device comprising: (a) a substrate having a first and a second through-via; (b) a porous dielectric material located inside the substrate and being in liquid communication with the through-vias; (c) a first capacitive electrode located on the substrate adjacent to the first through-via, the first capacitive electrode having an inner surface proximate to the first through-via; (d) a second capacitive electrode located on the substrate adjacent to the second through-via, the second capacitive electrode having an inner surface proximate to the second through-via; wherein each inner surface has a current flux and wherein the electrodes are shaped so that the current flux varies by less than a factor of two over an area of the inner surfaces greater than an effective area of the porous dielectric material and wherein in the current flux is less than about 20 microamperes/cm2 over an area of the inner surfaces greater than an effective area of the porous dielectric material; (e) a first flexible barrier encapsulating the first through-via and the first electrode and forming a first reservoir; (f) a second flexible barrier encapsulating the second through-via and the second electrode and forming a second reservoir; (g) a first enclosure surrounding the first flexible barrier and having a first port; (h) a second enclosure surrounding the second flexible barrier and having a second port; and, (i) a conduit connecting the first port to the second port. ### Claim 21 (depends on 20) The device of claim 20 further comprising a voltage drop between the electrodes, wherein the first reservoir contains and the porous dielectric material is saturated with an electrically conducting fluid so that the fluid moves from the first reservoir through the porous dielectric material and into the second reservoir and wherein a working fluid is contained between the second enclosure and the second flexible bather so that as the electrically conducting fluid fills the second reservoir, the second flexible barrier expands and pushes the working fluid through the second port. ### Claim 22 (depends on 21) The device of claim 21 wherein fluid flows unidirectionally through the porous dielectric material for a period of time without significant electrolysis of the electrically conducting fluid. ### Claim 23 (depends on 22) The device of claim 22 wherein the period of time is at least one day. ### Claim 24 (depends on 22) The device of claim 22 wherein the period of time is at least six days.