# US 6,719,535 B2 · Variable potential electrokinetic device

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- Number: US 6,719,535 B2
- Document ID: US6719535B2
- Status: Granted
- Kind: B2
- Application number: 10/066,528
- Filed: 2002-01-31
- Published: 2003-07-31
- Granted: 2004-04-13
- Earliest claimed: 2002-01-31
- Assignees: Eksigent Technologies, LLC
- Inventors: David J. Rakestraw; David W. Neyer
- Web page: https://patentgrep.com/patent/US6719535B2

## 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
- Y10S 977/70: Nanostructure
- Y10S 977/932: for electronic or optoelectronic application
- 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)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Variable potential electrokinetic devices and electrokinetic multipliers used for pumping and flow control are disclosed that offer improvements in safety and design flexibility. The devices of the present invention take advantage of combinations of pumping conduits and conducting conduits to permit the use of lower operating voltages in pumps, pressure multipliers, and flow controllers. Devices having N pumping stages and 2N+1 electrodes permit the use of arbitrary voltages at the fluid connection points between the devices and other system components, further improving device safety and flexibility.

## Claims

### Claim 1

An electrokinetic device, comprising:
a pumping conduit having a first end and a second end, and including a porous dielectric material;
a conducting conduit having a first end and a second end, said pumping conduit second end and said conducting conduit first end connecting at a junction; and
at least one electrode in electrical communication with said pumping conduit and said conducting conduit, the total number of electrodes being odd.

### Claim 2 (depends on 1)

The electrokinetic device of claim 1, wherein said odd number of electrodes comprises a first electrode at potential V1 in electrical communication with said pumping conduit first end, a second electrode at potential V2 in electrical communication with said pumping conduit second end, and a third electrode at potential V3 in electrical communication with said conducting conduit second end, and wherein V1 does not equal V2.

### Claim 3 (depends on 2)

The electrokinetic device of claim 2, wherein V3 does not equal V2.

### Claim 4 (depends on 2)

The electrokinetic device of claim 2, wherein V1, V2, and V3 are selected so that (V2−V1) and (V3−V2) are oppositely signed.

### Claim 5 (depends on 4)

The electrokinetic device of claim 4, wherein V1 is equal to V3.

### Claim 6 (depends on 5)

The electrokinetic device of claim 5, wherein said potentials V1 and V3 are ground potentials.

### Claim 7 (depends on 1)

The electrokinetic device of claim 1, wherein said conducting conduit includes a porous material.

### Claim 8 (depends on 1)

The electrokinetic device of claim 1, wherein said conducting conduit hydrodynamic conductance, kc, is greater than said pumping conduit hydrodynamic conductance, kp.

### Claim 9 (depends on 8)

The electrokinetic device of claim 8, wherein kc/kp≧2.

### Claim 10 (depends on 9)

The electrokinetic device of claim 9, wherein kc/kp≧10.

### Claim 11 (depends on 10)

The electrokinetic device of claim 10, wherein kc/kp≧100.

### Claim 12 (depends on 11)

The electrokinetic device of claim 11, wherein kc/kp≧1000.

### Claim 13 (depends on 12)

The electrokinetic device of claim 12, wherein kc/kp≧10,000.

### Claim 14 (depends on 1)

The electrokinetic device of claim 1, wherein said conducting conduit electrokinetic pressure value, pekc, is less than said pumping conduit electrokinetic pressure value, pekp.

### Claim 15 (depends on 14)

The electrokinetic device of claim 14, wherein pekc/pekp≦0.5.

### Claim 16 (depends on 15)

The electrokinetic device of claim 15, wherein pekc/pekp≦0.1.

### Claim 17 (depends on 16)

The electrokinetic device of claim 16, wherein pekc/pekp≦0.01.

### Claim 18 (depends on 17)

The electrokinetic device of claim 17, wherein pekc/pekp≦0.001.

### Claim 19 (depends on 18)

The electrokinetic device of claim 18, wherein pekc/pekp≦0.0001.

### Claim 20 (depends on 1)

The electrokinetic device of claim 1, wherein said conducting conduit electrical resistance, Rc, is greater than or equal to said pumping conduit electrical resistance, Rp.

### Claim 21 (depends on 20)

The electrokinetic device of claim 20, wherein Rc/Rp≧2.

### Claim 22 (depends on 21)

The electrokinetic device of claim 21, wherein Rc/Rp≧5.

### Claim 23 (depends on 22)

The electrokinetic device of claim 22, wherein Rc/Rp≧10.

### Claim 24 (depends on 23)

The electrokinetic device of claim 23, wherein Rc/Rp≧100.

### Claim 25 (depends on 1)

The electrokinetic device of claim 1, wherein said device is capable of generating 0.1 psi/volt applied across said pumping conduit.

### Claim 26 (depends on 25)

The electrokinetic device of claim 25, wherein said device is capable of generating 1 psi/volt applied across said pumping conduit.

### Claim 27 (depends on 26)

The electrokinetic device of claim 26, wherein said device is capable of generating 10 psi/volt applied across said pumping conduit.

### Claim 28 (depends on 1)

A method of controlling the flow of a fluid, comprising: contacting said pumping conduit first end of the electrokinetic device of claim 1 with a fluid; and supplying potential V1 to a first electrode in electrical communication with said pumping conduit first end, potential V2 to a second electrode in electrical communication with said junction, and potential V3 to a third electrode in electrical communication with said conducting conduit second end.

### Claim 29 (depends on 28)

The method of claim 28, wherein V1 does not equal V2.

### Claim 30 (depends on 28)

The method of claim 28, wherein V3 does not equal V2.

### Claim 31 (depends on 28)

The method of claim 28, wherein V1, V2, and V3 are selected so that (V2−V1) and (V3−V2) are oppositely signed.

### Claim 32 (depends on 28)

The method of claim 28, wherein V1 is equal to V3.

### Claim 33 (depends on 32)

The method of claim 32, wherein said potentials V1 and V3 are ground potentials.

### Claim 34 (depends on 28)

The method of claim 28, further comprising supplying a pressure-driven flow to said pumping conduit, and modulating said pressure-driven flow by an electroosmotically-driven flow component generated within said pumping conduit.

### Claim 35

An electrokinetic device, comprising:
a first pumping conduit having a first end and a second end, and including a first porous dielectric material;
a first conducting conduit having a first end and a second end, said first pumping conduit second end and said first conducting conduit first end connecting at a first junction;
a second pumping conduit having a first end and a second end, and including a second porous dielectric material, said first conducting conduit second end and said second pumping conduit first end connecting at a second junction; and
a first electrode in electrical communication with said first pumping conduit first end, a second electrode in electrical communication with said first junction, a third electrode in electrical communication with said second junction, and a fourth electrode in electrical communication with said second pumping conduit second end,
wherein said conducting conduit electrokinetic pressure value, pekc, is less than or equal to the electrokinetic pressure value, pekc/pekp, of at least one of said pumping conduits.

### Claim 36 (depends on 35)

The electrokinetic device of claim 35, wherein pekc/pekp≦0.5.

### Claim 37 (depends on 36)

The electrokinetic device of claim 36, wherein pekc/pekp≦0.1.

### Claim 38 (depends on 37)

The electrokinetic device of claim 37, wherein pekc/pekp≦0.01.

### Claim 39 (depends on 38)

The electrokinetic device of claim 38, wherein pekc/pekp≦0.001.

### Claim 40 (depends on 39)

The electrokinetic device of claim 39, wherein pekc/pekp≦0.0001.

### Claim 41 (depends on 35)

The electrokinetic device of claim 35, wherein said conducting conduit hydrodynamic conductance, kc, is greater than or equal to the hydrodynamic conductance, kp, of at least one of said pumping conduits.

### Claim 42 (depends on 41)

The electrokinetic device of claim 41, wherein kc/kp≧2.

### Claim 43 (depends on 42)

The electrokinetic device of claim 42, wherein kc/kp≧10.

### Claim 44 (depends on 43)

The electrokinetic device of claim 43, wherein kc/kp≧100.

### Claim 45 (depends on 44)

The electrokinetic device of claim 44, wherein kc/kp≧1000.

### Claim 46 (depends on 45)

The electrokinetic device of claim 45, wherein kc/kp≧10,000.

### Claim 47 (depends on 35)

The electrokinetic device of claim 35, wherein said conducting conduit electrical resistance, Rc, is greater than or equal to the electrical resistance, Rp, of at least one of said pumping conduits.

### Claim 48 (depends on 47)

The electrokinetic device of claim 47, wherein Rc/Rp≧2.

### Claim 49 (depends on 48)

The electrokinetic device of claim 48, wherein Rc/Rp≧5.

### Claim 50 (depends on 49)

The electrokinetic device of claim 49, wherein Rc/Rp≧10.

### Claim 51 (depends on 50)

The electrokinetic device of claim 50, wherein Rc/Rp≧100.

### Claim 52 (depends on 35)

The electrokinetic device of claim 35, wherein at least one of said conduits is a microscale conduit.

### Claim 53 (depends on 35)

The electrokinetic device of claim 35, wherein said first electrode is at potential V1, said second electrode is at potential V2, said third electrode is at potential V3, and said fourth electrode is at potential V4, and wherein at least one of the differences (V1−V2) and (V3−V4) is not equal to zero.

### Claim 54 (depends on 53)

The electrokinetic device of claim 53, wherein V1, V2, and V3 are selected so that (V2−V1) and (V3−V2) are oppositely signed.

### Claim 55 (depends on 53)

The electrokinetic device of claim 53, wherein V1, V2, V3, and V4 are selected so that (V2−V1) and (V4−V3) are oppositely signed.

### Claim 56 (depends on 53)

The electrokinetic device of claim 53, wherein V1, V2, V3, and V4 are selected so that (V2−V1) and (V4−V3) are same signed.

### Claim 57 (depends on 53)

The electrokinetic device of claim 53, wherein V1 is equal to V4.

### Claim 58 (depends on 57)

The electrokinetic device of claim 57, wherein said potentials V1 and V4 are ground potentials.

### Claim 59 (depends on 35)

The electrokinetic device of claim 35, wherein said first porous dielectric material is the same as said second porous dielectric material.

### Claim 60 (depends on 35)

The electrokinetic device of claim 35, wherein said first porous dielectric material is different from said second porous dielectric material.

### Claim 61 (depends on 60)

The electrokinetic device of claim 60, wherein said first and said second porous dielectric materials have oppositely-signed zeta potentials when contacted with a pumping fluid.

### Claim 62 (depends on 35)

The electrokinetic device of claim 35, wherein said conducting conduit includes a porous material.

### Claim 63 (depends on 35)

The electrokinetic device of claim 35, wherein said device is capable of generating an electroosmotic force on an aqueous fluid.

### Claim 64 (depends on 35)

The electrokinetic device of claim 35, wherein said device is capable of generating an electroosmotic force on a fluid mixture comprising an aqueous component and an organic component.

### Claim 65 (depends on 35)

The electrokinetic device of claim 35, wherein said device is capable of generating 0.05 psi/volt applied across said first and said second pumping conduits.

### Claim 66 (depends on 65)

The electrokinetic device of claim 65, wherein said device is capable of generating 2 psi/volt applied across said first and said second pumping conduits.

### Claim 67 (depends on 35)

A method of controlling the flow of a fluid, comprising:
contacting at least one end of said first pumping conduit or said second pumping conduit of the electrokinetic device of claim 35 with a fluid; and
supplying potential V1 to a first electrode in electrical communication with said first pumping conduit first end, potential V2 to a second electrode in electrical communication with said first junction, potential V3 to a third electrode in electrical communication with said second junction, and potential V4 to a fourth electrode in electrical communication with said second pumping conduit second end.

### Claim 68 (depends on 67)

The method of claim 67, wherein at least one of said differences (V1−V2) and (V3−V4) is not equal to zero.

### Claim 69 (depends on 67)

The method of claim 67, wherein at least one of said differences (V1−V2) and (V3−V4) is less than 200 volts.

### Claim 70 (depends on 67)

The method of claim 67, wherein V1, V2, and V3 are selected so that (V2−V1) and (V3−V2) are oppositely signed.

### Claim 71 (depends on 67)

The method of claim 67, wherein V1, V2, V3, and V4 are selected so that (V2−V1) and (V4−V3) are oppositely signed.

### Claim 72 (depends on 67)

The method of claim 67, wherein V1, V2, V3, and V4 are selected so that (V2−V1) and (V4−V3) are same signed.

### Claim 73 (depends on 67)

The method of claim 67, wherein V1 is equal to V4.

### Claim 74 (depends on 73)

The method of claim 73, wherein said potentials V1 and V4 are ground potentials.

### Claim 75 (depends on 67)

The method of claim 67, further comprising supplying a pressure-driven flow to said device, and modulating said pressure-driven flow by an electroosmotically-driven flow component generated within said first or said second pumping conduit.

### Claim 76

An electrokinetic device, comprising:
a first pumping conduit having a first end and a second end, and including a first porous dielectric material;
a first conducting conduit having a first end and a second end, said first pumping conduit second end and said first conducting conduit first end connecting at a first junction;
a second pumping conduit having a first end and a second end, and including a second porous dielectric material, said second pumping conduit first end connecting to said first conducting conduit second end at a second junction;
a second conducting conduit having a first end and a second end, said second pumping conduit second end connecting to said second conducting conduit first end at a third junction; and
at least one electrode in electrical communication with each of said pumping conduits and said conducting conduits, the total number of electrodes being odd.

### Claim 77 (depends on 76)

The electrokinetic device of claim 76, wherein said odd number of electrodes comprises a first electrode at potential V1 in electrical communication with said first pumping conduit first end, a second electrode at potential V2 in electrical communication with said first junction, a third electrode at potential V3 in electrical communication with said second junction, a fourth electrode at potential V4 at said third junction, and a fifth electrode at potential V5 at said second conducting conduit second end, and wherein at least one of the differences (V1−V2) and (V3−V4) does not equal zero.

### Claim 78 (depends on 77)

The electrokinetic device of claim 77, wherein V2 does not equal V3.

### Claim 79 (depends on 77)

The electrokinetic device of claim 77, wherein V4 does not equal V5.

### Claim 80 (depends on 77)

The electrokinetic device of claim 77, wherein V1, V2, V4, and V5 are selected so that (V2−V1) and (V5−V4) are oppositely signed.

### Claim 81 (depends on 77)

The electrokinetic device of claim 77, wherein V1 is equal to V5.

### Claim 82 (depends on 81)

The electrokinetic device of claim 81, wherein said potentials V1 and V5 are ground potentials.

### Claim 83 (depends on 76)

The electrokinetic device of claim 76, wherein any of said conducting conduits includes a porous material.

### Claim 84 (depends on 76)

The electrokinetic device of claim 76, wherein said device is capable of generating an electroosmotic force on an aqueous fluid.

### Claim 85 (depends on 76)

The electrokinetic device of claim 76, wherein said device is capable of generating an electroosmotic force on a fluid mixture comprising an aqueous component and an organic component.

### Claim 86 (depends on 76)

The electrokinetic device of claim 76, wherein said device is capable of generating 0.05 psi/volt applied across said first and said second pumping conduits.

### Claim 87 (depends on 76)

The electrokinetic device of claim 76, wherein said device is capable of generating 2 psi/volt applied across said first and said second pumping conduits.

### Claim 88 (depends on 76)

The electrokinetic device of claim 76, wherein the hydrodynamic conductance, kc, of at least one of said conducting conduits is greater than the hydrodynamic conductance, kp, of at least one of said pumping conduits.

### Claim 89 (depends on 88)

The electrokinetic device of claim 88, wherein kc/kp≧2.

### Claim 90 (depends on 89)

The electrokinetic device of claim 89, wherein kc/kp≧10.

### Claim 91 (depends on 90)

The electrokinetic device of claim 90, wherein kc/kp≧100.

### Claim 92 (depends on 91)

The electrokinetic device of claim 91, wherein kc/kp≧1000.

### Claim 93 (depends on 92)

The electrokinetic device of claim 92, wherein kc/kp≧10,000.

### Claim 94 (depends on 76)

The electrokinetic device of claim 76, wherein the electrokinetic pressure value, pekc, of at least one of said conducting conduits is less than the electrokinetic pressure value, pekc, of at least one of said pumping conduits.

### Claim 95 (depends on 94)

The electrokinetic device of claim 94, wherein pekc/pekp≦0.5.

### Claim 96 (depends on 95)

The electrokinetic device of claim 95, wherein pekc/pekp≦0.1.

### Claim 97 (depends on 96)

The electrokinetic device of claim 96, wherein pekc/pekp≦0.01.

### Claim 98 (depends on 97)

The electrokinetic device of claim 97, wherein pekc/pekp≦0.001.

### Claim 99 (depends on 98)

The electrokinetic device of claim 98, wherein pekc/pekp≦0.0001.

### Claim 100 (depends on 76)

The electrokinetic device of claim 76, wherein the electrical resistance, Rc, of at least one of said conducting conduits is greater than or equal to the electrical resistance, Rp, of at least one of said pumping conduits.

### Claim 101 (depends on 100)

The electrokinetic device of claim 100, Rc/Rp≧2.

### Claim 102 (depends on 101)

The electrokinetic device of claim 101, wherein Rc/Rp≧5.

### Claim 103 (depends on 102)

The electrokinetic device of claim 102, wherein Rc/Rp≧10.

### Claim 104 (depends on 103)

The electrokinetic device of claim 103, wherein Rc/Rp≧100.

### Claim 105 (depends on 76)

The electrokinetic device of claim 76, wherein said odd number of electrodes comprises a first electrode at potential V1 in electrical communication with said first pumping conduit first end, and an Nth electrode at potential VN in electrical communication with a second end of a terminal conducting conduit.

### Claim 106 (depends on 105)

The electrokinetic device of claim 105, wherein V1 is equal to VN.

### Claim 107 (depends on 106)

The electrokinetic device of claim 106, wherein said potentials V1 and VN are ground potentials.

### Claim 108 (depends on 76)

A method of controlling the flow of a fluid, comprising:
contacting at least one end of said first pumping conduit or said second pumping conduit of the electrokinetic device of claim 76 with a fluid; and
supplying potential V1 to a first electrode in electrical communication with said first pumping conduit first end, potential V2 to a second electrode in electrical communication with said first junction, potential V3 to a third electrode in electrical communication with said second junction, potential V4 to a fourth electrode in electrical communication with said third junction, and potential V5 to said second conducting conduit second end.

### Claim 109 (depends on 108)

The method of claim 108, wherein at least one of the differences (V1−V2) and (V3−V4) is not equal to zero.

### Claim 110 (depends on 108)

The method of claim 108, wherein V2 does not equal V3.

### Claim 111 (depends on 108)

The method of claim 108, wherein V4 does not equal V5.

### Claim 112 (depends on 108)

The method of claim 108, wherein V1, V2, V4, and V5 are selected so that (V2−V1) and (V5−V4) are oppositely signed.

### Claim 113 (depends on 108)

The method of claim 108, wherein V1 is equal to V5.

### Claim 114 (depends on 113)

The method of claim 113, wherein said potentials V1 and V5 are ground potentials.

### Claim 115 (depends on 108)

The method of claim 108, further comprising supplying a pressure-driven flow to said device, and modulating said pressure-driven flow by an electroosmotically-driven flow component generated within said first or said second pumping conduit.

### Claim 116

An electrokinetic device, comprising:
a pumping conduit having a first end and a second end, and including a porous dielectric material;
a conducting conduit having a first end and a second end, said pumping conduit second end and said conducting conduit first end connecting at a junction; and
a first electrode at potential V1 in electrical communication with said pumping conduit first end, a second electrode at potential V2 in electrical communication with said junction, and a third electrode at potential V3 in electrical communication with said conducting conduit second end.

### Claim 117 (depends on 116)

The electrokinetic device of claim 116, wherein V1 does not equal V2.

### Claim 118 (depends on 116)

The electrokinetic device of claim 116, wherein V3 does not equal V2.

### Claim 119 (depends on 116)

The electrokinetic device of claim 116, wherein V1, V2, and V3 are selected so that (V2−V1) and (V3−V2) are oppositely signed.

### Claim 120 (depends on 116)

The electrokinetic device of claim 116, wherein V1 is equal to V3.

### Claim 121 (depends on 120)

The electrokinetic device of claim 120, wherein said potentials V1 and V3 are ground potentials.

### Claim 122 (depends on 116)

The electrokinetic device of claim 116, wherein said conducting conduit includes a porous material.

### Claim 123 (depends on 116)

The electrokinetic device of claim 116, wherein said conducting conduit hydrodynamic conductance, kc, is greater than said pumping conduit hydrodynamic conductance, kp.

### Claim 124 (depends on 123)

The electrokinetic device of claim 123, wherein kc/kp≧2.

### Claim 125 (depends on 124)

The electrokinetic device of claim 124, wherein kc/kp≧10.

### Claim 126 (depends on 125)

The electrokinetic device of claim 125, wherein kc/kp≧100.

### Claim 127 (depends on 126)

The electrokinetic device of claim 126, wherein kc/kp≧1000.

### Claim 128 (depends on 127)

The electrokinetic device of claim 127, wherein kc/kp≧10,000.

### Claim 129 (depends on 116)

The electrokinetic device of claim 116, wherein said conducting conduit electrokinetic pressure value, pekc, is less than said pumping conduit electrokinetic pressure value, pekp.

### Claim 130 (depends on 129)

The electrokinetic device of claim 129, wherein pekc/pekp≦0.5.

### Claim 131 (depends on 130)

The electrokinetic device of claim 130, wherein pekc/pekp≦0.1.

### Claim 132 (depends on 131)

The electrokinetic device of claim 131, wherein pekc/pekp≦0.01.

### Claim 133 (depends on 132)

The electrokinetic device of claim 132, wherein pekc/pekp≦0.001.

### Claim 134 (depends on 133)

The electrokinetic device of claim 133, wherein pekc/pekp≦0.0001.

### Claim 135 (depends on 116)

The electrokinetic device of claim 116, wherein said conducting conduit electrical resistance, Rc, is greater than or equal to said pumping conduit electrical resistance, Rp.

### Claim 136 (depends on 135)

The electrokinetic device of claim 135, wherein Rc/Rp≧2.

### Claim 137 (depends on 136)

The electrokinetic device of claim 136, wherein Rc/Rp≧5.

### Claim 138 (depends on 137)

The electrokinetic device of claim 137, wherein Rc/Rp≧10.

### Claim 139 (depends on 138)

The electrokinetic device of claim 138, wherein Rc/Rp≧100.

### Claim 140 (depends on 116)

The electrokinetic device of claim 116, wherein said device is capable of generating 0.05 psi/volt applied across said pumping conduit.

### Claim 141 (depends on 140)

The electrokinetic device of claim 140, wherein said device is capable of generating 0.1 psi/volt applied across said pumping conduit.

### Claim 142 (depends on 141)

The electrokinetic device of claim 141, wherein said device is capable of generating 1 psi/volt applied across said pumping conduit.

### Claim 143 (depends on 142)

The electrokinetic device of claim 142, wherein said device is capable of generating 10 psi/volt applied across said pumping conduit.

### Claim 144

An electrokinetic device, comprising:
a first pumping conduit having a first end and a second end, and including a first porous dielectric material;
a first conducting conduit having a first end and a second end, said first pumping conduit second end and said first conducting conduit first end connecting at a first junction;
a second pumping conduit having a first end and a second end, and including a second porous dielectric material, said second pumping conduit first end connecting to said first conducting conduit second end at a second junction;
a second conducting conduit having a first end and a second end, said second pumping conduit second end connecting to said second conducting conduit first end at a third junction;
and a first electrode at potential V1 in electrical communication with said first pumping conduit first end, a second electrode at potential V2 in electrical communication with said first junction, a third electrode at potential V3 in electrical communication with said second junction, a fourth electrode at potential V4 in electrical communication with said third junction, and a fifth electrode at potential V5 in electrical communication with said second conducting channel second end.

### Claim 145 (depends on 144)

The device of claim 144, wherein at least one of the differences (V1−V2) and (V3−V4) does not equal zero.

### Claim 146 (depends on 144)

The electrokinetic device of claim 144, wherein V2 does not equal V3.

### Claim 147 (depends on 144)

The electrokinetic device of claim 144, wherein V4 does not equal V5.

### Claim 148 (depends on 144)

The electrokinetic device of claim 144, wherein V1, V2, V4, and V5 are selected so that (V2−V1) and (V5−V4) are oppositely signed.

### Claim 149 (depends on 144)

The electrokinetic device of claim 144, wherein V1 is equal to V5.

### Claim 150 (depends on 149)

The electrokinetic device of claim 149, wherein said potentials V1 and V5 are ground potentials.

### Claim 151 (depends on 144)

The electrokinetic device of claim 144, wherein any of said conducting conduits includes a porous material.

### Claim 152 (depends on 144)

The electrokinetic device of claim 144, wherein said device is capable of generating 0.05 psi/volt applied across said first and said second pumping conduits.

### Claim 153 (depends on 152)

The electrokinetic device of claim 152, wherein said device is capable of generating 2 psi/volt applied across said first and said second pumping conduits.

### Claim 154 (depends on 144)

The electrokinetic device of claim 144, wherein the hydrodynamic conductance, kc, of at least one of said conducting conduits is greater than the hydro dynamic conductance, kp, of at least one of said pumping conduits.

### Claim 155 (depends on 154)

The electrokinetic device of claim 154, wherein kc/kp≧2.

### Claim 156 (depends on 155)

The electrokinetic device of claim 155, wherein kc/kp≧10.

### Claim 157 (depends on 156)

The electrokinetic device of claim 156, wherein kc/kp≧100.

### Claim 158 (depends on 157)

The electrokinetic device of claim 157, wherein kc/kp≧1000.

### Claim 159 (depends on 158)

The electrokinetic device of claim 158, wherein kc/kp≧10,000.

### Claim 160 (depends on 144)

The electrokinetic device of claim 144, wherein the electrokinetic pressure value, pekc, of at least one of said conducting conduits is less than the electrokinetic pressure value, pekc, of at least one of said pumping conduits.

### Claim 161 (depends on 160)

The electrokinetic device of claim 160, wherein pekc/pekc≦0.5.

### Claim 162 (depends on 161)

The electrokinetic device of claim 161, wherein pekc/pekc≦0.1.

### Claim 163 (depends on 162)

The electrokinetic device of claim 162, wherein pekc/pekc≦0.01.

### Claim 164 (depends on 163)

The electrokinetic device of claim 163, wherein pekc/pekc≦0.001.

### Claim 165 (depends on 164)

The electrokinetic device of claim 164, wherein pekc/pekc≦0.0001.

### Claim 166 (depends on 144)

The electrokinetic device of claim 144, wherein the electrical resistance, Rc, of at least one of said conducting conduits is greater than or equal to the electrical resistance, Rp, of at least one of said pumping conduits.

### Claim 167 (depends on 166)

The electrokinetic device of claim 166, wherein Rc/Rp≧0.2.

### Claim 168 (depends on 167)

The electrokinetic device of claim 167, wherein Rc/Rp≧5.

### Claim 169 (depends on 168)

The electrokinetic device of claim 168, wherein Rc/Rp≧10.

### Claim 170 (depends on 169)

The electrokinetic device of claim 169, wherein Rc/Rp≧100.