FLUID FLOW CONTROL FREEZE/THAW VALVE FOR NARROW BORE CAPILLARIES OR MICROFLUIDIC DEVICES

• US 20030094206A1
• Filed: 11/19/2001
• Published: 05/22/2003
• Est. Priority Date: 11/19/2001
• Status: Active Grant

• Current Assignee: Waters Technologies Corporation (Waters Corporation)
• Original Assignee: Waters Investments Limited (Waters Corporation)
• Inventors: Gerhardt, Geoff C., Dourdeville, Theodore, Bouvier, Edouard S. P.
• Granted Patent: US 6,557,575 B1
• Time in Patent Office: Days
• US Class Current: 137/828
• CPC Class Codes: B01L 2400/0677 phase change valves; Meltable, freezing, dissolvable plugs; Destructible barriers
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: F16K 13/10 by means of liquid or granular medium
• CPC Class Codes: F16L 55/103 by temporarily freezing liquid sections in the pipe
• CPC Class Codes: G01N 2030/3038 temperature control of column exit, e.g. of restrictors
• CPC Class Codes: G01N 2030/6008 capillary restrictors
• CPC Class Codes: G01N 2035/00267 Meltable plugs
• CPC Class Codes: G01N 30/20 using a sampling valve
• CPC Class Codes: G01N 30/30 of temperature
• CPC Class Codes: G01N 30/6004 end pieces
• CPC Class Codes: G01N 30/6065 with varying cross section
• CPC Class Codes: Y10T 137/0391 Affecting flow by the addition of material or energy
• CPC Class Codes: Y10T 137/2196 Acoustical or thermal energy
• CPC Class Codes: Y10T 137/4643 Liquid valves

Abstract

Methods and devices for the management of fluid flow within nanoscale analytical systems, comprising a freeze thaw valve having differing geomentries to constrict a frozen plug within the freeze thaw segment. The freeze thaw valve is directed to use in high-pressure analytical systems. The geometry of an inner diameter of a channel or tube within a freeze thaw segment is configured to cause constriction of a freeze plug when axial force is applied. The constriction is used in the flow-path of a freeze thaw valve to prevent movement of the frozen plug at high pressures to avoid valve leakage.

Claims

1. A method for managing liquid flow through tubing or channels by freezing and thawing the liquid within a segment of capillary tubing or channels comprising the steps of:

configuring a constriction segment of an interior passage of said tubing or channels to have a constrictive geometry;

freezing the constriction segment to stop the passage of fluids; and

thawing the constriction segment to allow the passage of fluids.

2. The method of claim 1 wherein said interior passage is contained within a capillary tubing.

3. The method of claim 1 wherein said interior passage is a micro-channel.

4. The method of claim 1 wherein said liquid flow is under high pressure greater than 20,000 p.s.i.

5. The method of claim 1 wherein said freezing of said segment is by the use of carbon dioxide.

6. The method of claim 1 wherein said freezing of said segment is by the use of a heat pump.

7. The method of claim 1 wherein said constrictive geometry is tapered.

8. The method of claim 1 wherein said constrictive geometry is bulbous.

9. The method of claim 1 wherein said constrictive geometry has a first diameter and a second diameter and said first diameter is greater than said second diameter.

10. The method of claim 1 wherein said geometry is a degree bend.

11. An apparatus for managing liquid flow through tubing or channels by freezing and thawing the liquid within a segment of capillary tubing or channels comprising:

a valve segment having an interior diameter for fluid flow;

a constriction geometry within said interior diameter;

a means for freezing said fluid within said valve segment forming a frozen plug;

wherein said frozen plug stops fluid flow and is held in place by constrictive forces created by said constriction geometry; and

a means for thawing said fluid within said valve segment to allow fluid flow.

12. The apparatus of claim 11 wherein said liquid flow is under high pressure greater than 20,000 p.s.i.

13. The apparatus of claim 11 wherein said means for freezing said segment is by the use of carbon dioxide.

14. The apparatus of claim 11 wherein said means for freezing said segment is by the use of a heat pump.

15. The apparatus of claim 11 wherein said geometry is tapered.

16. The apparatus of claim 11 wherein said geometry is bulbous.

17. The apparatus of claim 11 wherein said geometry has a first diameter and a second diameter and said first diameter is greater than said second diameter.

18. The apparatus of claim 11 wherein said geometry is a bend.