Electroosmotic flow controller

• US 7,695,603 B2
• Filed: 08/08/2005
• Issued: 04/13/2010
• Est. Priority Date: 06/13/2001
• Status: Active Grant

• Current Assignee: AB Sciex LLC (Danaher Corporation)
• Original Assignee: Eksigent Technologies LLC
• Inventors: Paul, Phillip H., Bailey, Christopher G., Arnold, Don Wesley
• Primary Examiner(s): Nguyen; Nam X
• Assistant Examiner(s): Kaur; Gurpreet
• Application Number:
  US11/200,369
• Publication Number:
  US 20070000784A1
• Time in Patent Office: 1,709 Days
• Field of Search: 204450-455, 204/461, 204600-605, 222/594, 222/595, 137/2, 137/7, 137/12, 137/115.03
• US Class Current: 204/600
• CPC Class Codes: B01D 61/56 Electro-osmotic dewatering
• CPC Class Codes: G01N 2030/285 electrically driven carrier
• CPC Class Codes: G01N 2030/324 speed, flow rate
• CPC Class Codes: G01N 2030/326 pumps
• CPC Class Codes: G01N 30/32 of pressure or speed G01N30/36 takes precedence
• CPC Class Codes: G01N 30/34 of fluid composition, e.g. gradient G01N30/36 takes precedence
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: G05D 7/0694 by action on throttling means or flow sources of very small size, e.g. microfluidics microvalves F16K99/0001; microstructural devices per se B81B
• CPC Class Codes: Y10T 137/85978 With pump
• CPC Class Codes: Y10T 137/85986 Pumped fluid control
• CPC Class Codes: Y10T 137/86027 Electric

Abstract

Electroosmotic flow controllers and methods of fluid flow control are described. The invention uses an electroosmotically generated flow component in conjunction with a pressure driven flow component to modulate fluid flow. The devices and methods of the invention may include salt bridges for making electrical connection between a power supply and a channel filled with a porous dielectric material and a fluid. Embodiments including flow controllers and flow splitters are described as is their use in a variety of fluid handling applications.

Claims

1. A flow controller, comprising:

(a) a channel having

(i) a fluid inlet in liquid communication with a fluid source at pressure P1,

(ii) a fluid outlet at pressure P2, wherein P2<

P1, and

(iii) a porous dielectric material disposed in said channel;

(b) a fluid contained within said channel;

(c) spaced electrodes in electrical communication with said fluid;

(d) a power supply in electrical communication with said electrodes for applying an electric potential to said spaced electrodes;

(e) a first node between the fluid inlet and the porous dielectric material;

(f) a first flow element having a first flow element inlet in liquid communication at the first node at pressure PN with said fluid inlet and said fluid source, wherein P2<

PN, and a first flow element outlet at pressure P3;

(g) at least one sensor for monitoring at least one control signal; and

(h) a feedback control mechanism operatively connected to the sensor and the power supply;

whereby said electric potential generates an electroosmotically-driven flow component through said channel that modulates a pressure-driven flow component resulting from the P1−

P2 pressure differential;

whereby the electroosmotically driven flow component affects the proportion of fluid flowing through said channel and said first flow element; and

whereby the feedback control mechanism maintains the at least one control signal within a predetermined range by modulating the electric potential applied by the power supply.

2. The flow controller of claim 1, further comprising:

(f) a second flow element interposed between said fluid source and said first node, said second flow element having a second flow element inlet in liquid communication with said fluid source, and a second flow element outlet in liquid communication at said first node with said fluid inlet and said first flow element inlet.

3. The flow controller of claim 1, wherein said power supply is a variable power supply.

4. The flow controller of claim 1, wherein said pressure-driven and said electroosmotically-driven flow components through said channel are in the same direction.

5. The flow controller of claim 1, wherein said pressure-driven and said electroosmotically-driven flow components through said channel are in the opposite direction and the pressure-driven fluid flux is greater than or equal to the electroosmotically driven fluid flux.

6. The flow controller of claim 1, wherein said electrical communication is through a bridge.

7. The flow controller of claim 1, wherein said channel has a circular cross-section.

8. The flow controller of claim 1, wherein said channel comprises a fused silica capillary.

9. The flow controller of claim 1, wherein the porous dielectric material includes silica particles.

10. The flow controller of claim 9, wherein the silica particles have a diameter of between about 100 nm and 5 μ

m.

11. The flow controller of claim 1, wherein the porous dielectric material includes porous dielectric materials fabricated by processes selected from the group consisting of lithographic patterning and etching, direct injection molding, sol-gel processing, and electroforming.

12. The flow controller of claim 1, wherein the porous dielectric material includes organic polymer materials.

13. The flow controller of claim 1, wherein said at least one sensor is selected from the group consisting of a pressure transducer, a flowmeter, a temperature sensor, a heat flux sensor, a displacement sensor, a load cell, a strain gauge, a conductivity sensor, a selective ion sensor, a pH sensor, a flow spectrophotometer, and a turbidity sensor.

14. The flow controller of claim 13, wherein said at least one sensor is a pressure transducer.

15. The flow controller of claim 14, wherein said pressure transducer is a differential pressure transducer.

16. The flow controller of claim 13, wherein said at least one sensor is a flowmeter.