Backflow prevention for high pressure gradient systems

• US 20050008516A1
• Filed: 08/04/2004
• Published: 01/13/2005
• Est. Priority Date: 12/09/2002
• Status: Active Grant

• Current Assignee: Waters Investments Limited (Waters Corporation)
• Original Assignee: Waters Investments Limited (Waters Corporation)
• Inventors: Richardson, Hal, Andrews, Richard W.
• Granted Patent: US 7,396,469 B2
• Time in Patent Office: Days
• US Class Current: 417/540
• CPC Class Codes: G01N 2030/322 pulse dampers
• CPC Class Codes: G01N 2030/328 valves, e.g. check valves of pumps
• CPC Class Codes: G01N 30/10 using a splitter
• 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: G01N 30/36 in high pressure liquid systems
• CPC Class Codes: Y10T 137/7838 Plural
• CPC Class Codes: Y10T 137/87684 Valve in each inlet

Abstract

Gradient performance with high pressure gradient solvent delivery system is optimized by approximation of infinite stroke volume of high pressure pumps by the addition of pulse dampening with backflow prevention to each high pressure pump. The backflow prevention adds sufficient minimum flow resistance, thereby enhancing the performance of the pulse dampening over a wider range of flow rates resulting in consistent gradient performance.

Claims

1. A method for improving the compositional accuracy of high pressure gradient pumps for high pressure liquid chromatography comprising the steps of:

providing a first solvent line having a first set of pumps and a second solvent line having a second set of pumps said first set of pumps being in fluid communication with to a first solvent reservoir and said second set of pumps being in fluid communication with a second solvent reservoir;

connecting said first set of pumps to a first pulse dampener and connecting said second set of pumps to a second pulse dampener said first pulse dampener being in fluid communication with a first backflow preventor and said second pulse dampener being in fluid communication with a second blackflow preventor wherein said backflow preventors substantially reduce fluidic cross talk between said solvent lines;

connecting said backflow preventors to a mixing tee to deliver solvent composition.

2. The method of backflow prevention according to claim 1 wherein said backflow preventors improve compositional accuracy.

3. The method of backflow regulation according to claim 1 wherein said backflow preventors allow accurate compositional delivery at flow rates substantially less than the volumes of said pulse dampeners.

4. The method of backflow regulation according to claim 1 wherein said backflow preventors allow accurate compositional delivery at flow rates substantially equivalent to displaced volumes of each pump chamber of said pumps.

5. The method of backflow prevention according to claim 1 wherein said backflow preventors are incorporated in said mixing tee to reduce delay volume.

6. The method of backflow prevention according to claim 5 wherein said incorporated backflow preventors have backpressure regulators.

7. The method of backflow prevention according to claim 1 further comprising the step of providing backpressure regulators having a selected fixed resistance said selected fixed resistance ensuring that said pulse dampeners function efficiently with consistent performance of primary check valves of said pumps.

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18. A high pressure liquid chromatography apparatus comprising:

a mixing tee having an outlet port, a first inlet port and a second inlet port; and

a backflow preventor incorporated within said first and second inlet port said backflow preventors having a selected coil spring and an actuator seated within a valve seat wherein said selected coil spring exerts a selected pressure upon said actuator.

19. The high pressure liquid chromatography apparatus according to claim 18 wherein said selected pressure is ranges between 0 and 2000 psi.

20. The high pressure liquid chromatography apparatus according to claim 18 wherein said incorporation reduces system volume.

21. The high pressure liquid chromatography apparatus according to claim 18 wherein said backflow preventors have a selected fixed resistance said selected fixed resistance ensuring that pulse dampeners within a chromatography system function efficiently with consistent performance of primary check valves of system pumps.

22. A high pressure liquid chromatography apparatus comprising:

a mixing tee having an outlet port, a first inlet port and a second inlet port; and

a backflow preventor incorporated within said first and second inlet port said backflow preventors having a ball bearing seated within a valve seat wherein said ball bearing limits fluid flow to a forward direction.