Plug unit and connection system for connecting capillary tubes

Patent metadata

Field	Value
Publication number	US-9945501-B2
Application number	US-201514819743-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Dec 2, 2008
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A plug unit and system for connecting capillary tubes, especially for high-performance liquid chromatography, with a plug capillary tube projecting through a hole of a plug housing, which is detachably connectable to a bushing unit. The plug capillary tube front end projects into a capillary tube receptacle in the bushing unit with its end face essentially aligned opposite a front end of a bushing capillary tube or a bushing capillary tube opening of the bushing unit, the end face of which is butted against. The plug housing applies a force, with its end face facing the plug capillary tube end, directly or indirectly on an annular sealing element surrounding the plug capillary tube in the region of the front end of the plug capillary tube such that the front end of the plug capillary tube is sealed through deformation of the sealing element against the capillary tube receptacle opening.

First claim

What is claimed is:

1. A plug connecting to a bushing comprising:
(a) a plug housing for holding a front end of a plug capillary tube, the plug housing having a central hole and an axial threaded region;
(b) the plug capillary tube configured to be disposed through the central hole of the plug housing, the plug capillary tube having a force-receiving region with a trumpet shape at the front end, in which the force-receiving region has an outer diameter increasing continuously towards an end face of the plug capillary tube;
(c) an annular sealing element configured to be mounted on the plug capillary tube towards the end face of the plug capillary tube, the annular sealing element having an inner diameter formed to enlarge along its length toward the end face of the plug capillary tube complementary to contours of the outer diameter of the force receiving region;
(d) an elongated pressure piece for mounting on the plug capillary tube between the plug housing and the annular sealing element;
wherein the plug housing is configured to be rotatably and detachably connected to the bushing, the bushing having a receptacle opening to receive the plug, the receptacle opening including a mating thread, in which the mating thread matches the axial threaded region of the plug housing, in which an inward directed portion of the receptacle opening has a cylindrical end region delimited by a bottom wall, in which the cylindrical end region opens to a bushing capillary passage,
the bushing is configured to receive the front end of the plug capillary tube into the cylindrical end region of the receptacle opening where the end face of the front end of the plug capillary tube is essentially aligned opposite a front end of the bushing capillary passage of the bushing and the end face of the plug capillary tube is against the bottom wall of the cylindrical end region,
wherein the annular sealing element is configured to seal a radially outward region of the force-receiving region and a cylinder wall of the cylindrical end region so that a dead volume is avoided in the cylindrical end region of the receptacle opening when the plug housing is rotatably connected to the bushing, the plug housing applies an inward axial force to the pressure piece, where a front end face of the pressure piece transmits an axial force without transmitting a friction from the plug housing to the annular sealing element, in which an end face of the annular sealing element applies an axial force on the force-receiving region of the front end of the plug capillary tube.

2. The plug of claim 1 , in which the pressure piece comprises
a first front end having an outer diameter smaller than an inner diameter of the cylindrical end region, and
a second rear end having an outer diameter that is larger than the outer diameter of the first front end and being smaller than an inner diameter of the receptacle opening.

3. The plug of claim 1 , in which a channel opening at the force-receiving region of the plug capillary tube has an inner diameter that is maintained at a same value of the plug capillary tube.

4. A connection system comprising:
(I) a plug rotatably connected to a bushing, the plug including
(a) a plug housing having a central hole and an axial threaded region;
(b) a plug capillary tube disposed through the central hole of the plug housing, the plug capillary tube having a force-receiving region with a trumpet shape at a front end, in which the force-receiving region has an outer diameter increasing continuously towards an end face of the plug capillary tube;
(c) an annular sealing element mounted on the plug capillary tube towards the end face of the plug capillary tube, the annular sealing element having an inner diameter formed to enlarge along its length toward the end face of the plug capillary tube complementary to contours of the outer diameter of the force receiving region;
(d) an elongated pressure piece mounted on the plug capillary tube between the plug housing and the annular sealing element; and

(II) the bushing having a receptacle opening to receive the plug housing, the receptacle opening including a mating thread, in which the mating thread is rotatably connected to the axial threaded region of the plug housing, in which an inward directed portion of the receptacle opening has a cylindrical end region delimited by a bottom wall, in which the cylindrical end region opens to a bushing capillary passage, the front end of the plug capillary tube is disposed into the cylindrical end region of the receptacle opening where the end face of the front end of the plug capillary tube is essentially aligned opposite a front end of the bushing capillary passage of the bushing and the end face of the plug capillary tube is against the bottom wall of the cylindrical end region,
wherein the annular sealing element pushes the end face of the plug capillary tube against the bottom wall and seals a radially outward region of the force-receiving region and a cylinder wall of the cylindrical end region so that a dead volume is avoided in the cylindrical end region of the receptacle opening when the plug housing is rotatably connected to the bushing, the plug housing applies an inward axial force to the pressure piece, such that a front end face of the pressure piece transmits an axial force without transmitting a friction from the plug housing to the annular sealing element, where an end face of the annular sealing element plastically deforms and applies an axial force on the force-receiving region of the front end of the plug capillary tube.

5. The connection system of claim 4 , in which the pressure piece comprises:
a first front end having an outer diameter smaller than an inner diameter of the cylindrical end region, and
a second rear end having an outer diameter that is larger than the outer diameter of the first front end and being essentially equal to an inner diameter of the receptacle opening.

6. The connection system of claim 4 , in which a channel opening at the force-receiving region of the plug capillary tube has an inner diameter that is maintained at a same value of the plug capillary tube.

Assignees

• Dionex Softron Gmbh

Inventors

• Hochgraeber Hermann
• Satzinger Adolf

Classifications

• G01N30/6039 Primary

  in series · CPC title

• F16L21/04 Primary

  in which sealing rings are compressed by axially-movable members · CPC title

• G01N30/6091

  Cartridges · CPC title

• F16L19/061

  a pressure ring being arranged between the clamping ring and the threaded member or the connecting member · CPC title

• F16L21/035

  placed around the spigot end before connection ({F16L21/022,} F16L21/025 take precedence) · CPC title