Sampling device at high precision and high pressure utilizing two drives

Patent metadata

Field	Value
Publication number	US-10234433-B2
Application number	US-201414534027-A
Country	US
Kind code	B2
Filing date	Nov 5, 2014
Priority date	Nov 8, 2013
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

The invention relates to a sampler for providing a sample for high-performance liquid chromatography, in which a volume of liquid to be taken up into a cylinder can be aspirated by means of a first drive and can be compressed to a high pressure level by means of a second drive independent of the first drive or can be decompressed from this level in a controlled manner.

First claim

What is claimed is:

1. A sampling device for collecting and dispensing a sample volume for liquid chromatography, the sampling device comprising:
a) a piston in a cylinder,
b) the piston configured to be movable along a cylinder axis to collect the sample volume in the cylinder, and
c) two drives configured to generate different piston forces on the piston, in which the two drives are independent of each other, each drive is configured to be coupled to and uncoupled from the piston independently of a respective other drive,
wherein the two drives each include respective coupling means, the coupling means each configured to transfer a force of the respective drive to the piston, and the respective coupling means extend concentrically with respect to each other and to the cylinder axis in at least one section,
wherein a second drive of the two drives is configured as a compression drive to generate pressure forces of over 100 MPa in the cylinder,
wherein a first drive of the two drives is configured as a metering drive to aspirate the sample volume into the cylinder,
wherein the metering drive comprises an axially movable toothed belt pulley configured as a spindle nut of the metering drive where the spindle nut of the metering drive is screwed along a stationary spindle to transfer a drive force to the piston, and
wherein the coupling means of the metering drive engages on the spindle nut of the metering drive via a magnet, the magnet arranged in an interior of the spindle nut of the metering drive, the magnet is configured to detach from the spindle nut of the metering drive in an axial direction along the cylinder axis when a shearing force exerted on the spindle nut of the metering drive exceeds a holding force of the magnet.

2. The sampling device as claimed in claim 1 , wherein the coupling means of the metering drive comprises a pin arranged concentrically with respect to the cylinder axis, in which the pin transfers force from the metering drive to the piston with a ball, the ball being disposed between the pin and the piston.

3. The sampling device as claimed in claim 2 , wherein the spindle of the compression drive is a hollow tube where the hollow tube guides the pin.

4. A sampling device for collecting and dispensing a sample volume for liquid chromatography, the sampling device comprising:
a piston reciprocally movable within a cylinder along a cylinder axis,
a first metering drive controlling movement of the piston in a first direction along the cylinder axis to collect the sample volume within the cylinder, and
a second compression drive controlling movement of the piston in a second opposite direction along the cylinder axis to bring the cylinder to a desired pressure,
in which the first metering drive is mechanically uncoupled from the second compression drive while the first metering drive controls piston movement, and the second compression drive is mechanically uncoupled from the first metering drive while the second compression drive controls piston movement,
whereby the first metering drive imparts actuating forces on the piston to collect the sample volume, and the second compression drive imparts compression forces on the piston to bring the cylinder to the desired pressure, wherein the actuating forces are lower than the compression forces.

5. The sampling device as claimed in claim 4 , wherein the first metering drive and the second compression drive each include respective first and second coupling means configured to engage the piston, and the respective coupling means extend concentrically with respect to each other and to the cylinder axis.

6. The sampling device as claimed in claim 5 , wherein the first coupling means is a pin extending through the second coupling means.

7. The sampling device as claimed in claim 4 , wherein the piston is not subjected to the actuating forces while the second compression drive subjects the piston to the compression forces, and the piston is not subjected to the compression forces while the first metering drive subjects the piston to the actuating forces.

8. The sampling device as claimed in claim 7 , wherein the actuating forces allow collection of the sample volume at ambient pressure and the compression forces subject the cylinder to pressures in excess of 100 MPa.

9. A sampling device for collecting and dispensing a sample volume for liquid chromatography, the sampling device comprising:
a piston reciprocally movable within a cylinder along a cylinder axis,
a first metering drive controlling movement of the piston in a first direction along the cylinder axis to collect the sample volume within the cylinder, and
a second compression drive controlling movement of the piston in a second opposite direction along the cylinder axis to bring the cylinder to a desired pressure,
in which the second compression drive is mechanically uncoupled from the piston while the first metering drive controls piston movement, and the first metering drive is mechanically uncoupled from the piston while the second compression drive controls piston movement.

10. The sampling device as claimed in claim 9 , wherein each of the first and second drives include respective coupling means configured to transfer a force of the respective drive to the piston, and the respective coupling means extend concentrically with respect to each other and to the cylinder axis in at least one section.

11. The sampling device as claimed in claim 10 , wherein the first metering drive applies a force to the piston along the cylinder axis, the first metering drive is configured with an overload safeguard to axially separate a coupling between the first metering drive and the coupling means of the first metering drive.

12. The sampling device as claimed in claim 9 , wherein the piston is urged into a retracted position by a tensioning means.

13. The sampling device as claimed in claim 12 , in which the tensioning means comprises a spring.

14. The sampling device as claimed in claim 9 , wherein the second compression drive is configured to generate pressure forces of over 100 MPa in the cylinder.

15. The sampling device as claimed in claim 14 , wherein the second compression drive is also configured to reduce pressure.

16. The sampling device as claimed in claim 14 , wherein the second compression drive comprises a stationary toothed belt pulley configured as a spindle nut of the compression drive to transfer a drive force to a spindle axially movable in a center of the spindle nut of the second compression drive, in which the spindle applies force to the piston.

17. The sampling device as claimed in claim 16 , in which the spindle applies force to the piston via a connecting piece.

18. The sampling device as claimed in claim 9 , wherein the first metering drive comprises an axially movable toothed belt pulley configured as a spindle nut of the metering drive where the spindle nut of the metering drive is screwed along a stationary spindle to transfer a drive force to the piston.

19. The sampling device as claimed in claim 9 , wherein the first metering drive applies a force to the piston along the cylinder axis, the first metering drive is configured with an overload safeguard to axially separate a coupling between the metering drive and the piston.

Assignees

• Dionex Softron Gmbh

Inventors

• Satzinger Adolf
• Hochgraeber Hermann
• Eichorn Thomas Armin Alexander

Classifications

• G01N2030/207

  with metering cavity, e.g. sample loop · CPC title

• F04B13/00

  Pumps specially modified to deliver fixed or variable measured quantities · CPC title

• G01N30/20 Primary

  using a sampling valve · CPC title

• G01N30/22

  in high pressure liquid systems · CPC title