Plug unit and connection system for connecting capillaries, particularly for high-performance liquid chromatography

• US 10,067,102 B2
• Filed: 07/06/2015
• Issued: 09/04/2018
• Est. Priority Date: 05/22/2009
• Status: Active Grant

• Current Assignee: Dionex Softron GmbH (Thermo Fisher Scientific Incorporated)
• Original Assignee: Dionex Softron GmbH (Thermo Fisher Scientific Incorporated)
• Inventors: Hochgraeber, Hermann, Satzinger, Adolf, Buerger, Daniel, Unger, Andreas
• Primary Examiner(s): Dunwoody, Aaron M
• Application Number:
  US14/792,215
• Publication Number:
  US 20150308989A1
• Time in Patent Office: 1,156 Days
• Field of Search: 285356, 285353, 285357, 285322, 285323, 285324, 285342, 285384, 285385
• CPC Class Codes: F16L 25/0018 Abutment joints
• CPC Class Codes: F16L 37/02 in which the connection is maintained only by friction of the parts being joined F16L37/22 takes precedence
• CPC Class Codes: G01N 2030/027 Liquid chromatography
• CPC Class Codes: G01N 30/6026 Fluid seals

Abstract

A plug unit for connecting capillary tubes includes a plug housing that has an axial borehole, a plug capillary tube that projects through the axial borehole, and a sealing element that surrounds the plug capillary tube. The front end of the plug capillary tube is sealed by an elastic and/or plastic deformation of the sealing element against the capillary tube receptacle opening of a bushing unit. A hollow cylindrical pressure piece is provided that surrounds the sealing element in an axial region facing away from the end surface of the plug capillary tube, and the pressure piece has a rearward end side that faces away from the end surface of the plug capillary tube and that can be loaded by the plug housing with an axial pressure force when the plug unit and bushing unit are connected.

Claims

1. A plug unit for connecting a plug capillary tube, the plug unit including:

(a) a plug housing;

(b) the plug capillary tube projecting axially through the plug housing;

(c) an annular sealing element positioned so that a front end surface of the plug capillary tube is flush with a front end surface of the annular sealing element;

(d) wherein the plug housing is adapted to connect to a bushing unit;

(e) a pressure piece configured to receive a rear portion of the annular sealing element, the pressure piece having (i) a front end surface spaced rearwardly apart from the front end surface of the annular sealing element and (ii) a rearward end surface that faces away from the front end surface of the annular sealing element;

(f) wherein the pressure piece and the annular sealing element are both connected rigidly to the plug capillary tube so as to prevent relative movement between the pressure piece, the annular sealing element, and the plug capillary tube, and so that a front end region of the plug capillary tube, the annular sealing element, and the pressure piece are configured to be insertable simultaneously into a receptacle opening of the bushing unit with the front end region of the plug capillary tube projecting into a capillary tube receptacle opening of the bushing unit in alignment with a bushing capillary tube opening of the bushing unit; and

(g) wherein the front end region of the plug capillary tube, the annular sealing element, and the pressure piece are configured to be inserted into a fully inserted position in the capillary tube receptacle opening of the bushing unit, when the plug housing is placed in a connected position where the plug housing applies an axial force to the pressure piece, the annular sealing element, and the plug capillary tube so as to press at least the front end surface of the annular sealing element against a floor wall of the capillary tube receptacle opening of the bushing unit.

2. The plug unit of claim 1, wherein the front end region of the plug capillary tube has a hollow cylindrical construction with a constant cross section.

3. The plug unit of claim 1, wherein the front end region of the annular sealing element extends beyond the front end region of the pressure piece and wherein an outer diameter of the front end region of the annular sealing element corresponds to an outer diameter of the front end region of the pressure piece.

4. The plug unit of claim 1, wherein an inner diameter of the annular sealing element corresponds to an outer diameter of the plug capillary tube.

5. The plug unit of claim 1, wherein the pressure piece and the annular sealing element are both connected rigidly to the plug capillary tube by a friction fit or by the friction fit and a positive fit.

6. The plug unit of claim 1, wherein the pressure piece is connected through a crimped connection to the plug capillary tube or to the annular sealing element and the plug capillary tube.

7. The plug unit of claim 6, wherein the pressure piece has a two-part construction including a hollow cylindrical base part and an annular attachment part, and wherein the annular attachment part surrounds the base part and is crimped onto the base part so that the base part is also connected to the annular sealing element and the plug capillary tube, and wherein the annular attachment part has a triangular shape in a longitudinal section and is crimped onto the base part with a radially inward crimp at an acute-angled section of the triangular shape.

8. The plug unit of claim 7, wherein the crimped connection is created at an axial position of the plug capillary tube at which the annular sealing element is surrounded by the pressure piece.

9. The plug unit of claim 1, wherein the plug capillary tube comprises PEEK (polyether ether ketone).

10. The plug unit of claim 1, wherein a rigid connection between the pressure piece, the annular sealing element, and the plug capillary tube is generated by a friction fit.

11. The plug unit of claim 1, wherein the pressure piece is in position to abut a shoulder of the annular sealing element.

12. The plug unit of claim 1, wherein the plug unit is adapted to be connected into the bushing unit, wherein the receptacle opening has a larger inner diameter than the capillary tube receptacle opening and the bushing unit includes a transition portion between the receptacle opening and the capillary tube receptacle opening.

13. A connection system for connecting a plug capillary tube, the connection system including:

(a) a bushing unit having a receptacle opening in which is defined a capillary tube receptacle opening, the capillary tube receptacle opening including a floor wall and a bushing capillary tube opening located in the floor wall; and

(b) a plug unit including;

(i) a plug housing,

(ii) the plug capillary tube projecting axially through the plug housing,

(iii) an annular sealing element positioned so that a front end surface of the plug capillary tube is flush with a front end surface of the annular sealing element,

(iv) wherein the plug housing is adapted to connect to the bushing unit, and

(v) a pressure piece configured to receive a rear portion of the annular sealing element, the pressure piece having (i) a front end surface spaced rearwardly apart from the front end surface of the annular sealing element and (ii) a rearward end surface that faces away from the front end surface of the annular sealing element;

(c) wherein the pressure piece and the annular sealing element are both connected rigidly to the plug capillary tube so as to prevent relative movement between the pressure piece, the annular sealing element, and the plug capillary tube, and so that a front end region of the plug capillary tube, the annular sealing element, and the pressure piece are insertable simultaneously into the receptacle opening of the bushing unit with the front end region of the plug capillary tube projecting into the capillary tube receptacle opening in alignment with the bushing capillary tube opening; and

(d) wherein the front end region of the plug capillary tube, the annular sealing element, and the pressure piece are inserted into a fully inserted position in the capillary tube receptacle opening, when the plug housing is placed in a connected position where the plug housing applies an axial force to the pressure piece, the annular sealing element, and the plug capillary tube so as to press at least the front end surface of the annular sealing element against the floor wall of the capillary tube receptacle opening.

14. The connection system of claim 13, wherein the receptacle opening has a larger inner diameter than the capillary tube receptacle opening, and the bushing unit includes a transition portion between the receptacle opening and the capillary tube receptacle opening.

15. The connection system of claim 13, wherein when the front end region of the plug capillary tube, the annular sealing element, and the pressure piece are inserted into the fully inserted position in the receptacle opening, the front end surface of the pressure piece reaches at least up to the capillary tube receptacle opening or extends into the capillary tube receptacle opening.

16. The connection system of claim 13, wherein the front end region of the annular sealing element extends beyond the front end region of the pressure piece and wherein an outer diameter of the front end region of the annular sealing element corresponds to an outer diameter of the front end region of the pressure piece.

17. The connection system of claim 13, wherein an inner diameter of the annular sealing element corresponds to an outer diameter of the plug capillary tube.

18. The connection system of claim 17, wherein the pressure piece and the annular sealing element are both connected rigidly to the plug capillary tube by a friction fit or by the friction fit and a positive fit.

19. The connection system of claim 13, wherein the pressure piece is connected through a crimped connection to the plug capillary tube or to the annular sealing element and the plug capillary tube.

20. The plug unit of claim 13, wherein the plug capillary tube comprises PEEK (polyether ether ketone).

21. The connection system of claim 13, wherein the pressure piece is in position to abut a shoulder of the annular sealing element.

22. The connection system of claim 13, wherein a rigid connection between the pressure piece, the annular sealing element, and the plug capillary tube is generated by a friction fit.