Plug unit and connection system for connecting capillary tubes, especially for high-performance liquid chromatography

摘要

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.

主权项

1. A plug unit for connecting a capillary tube to a bushing unit of a high-pressure fluid handling system, the plug unit including:
(a) a plug housing having an axial borehole; (b) a plug capillary tube projecting through the axial borehole of the plug housing; (c) an elongated annular sealing element through which a front end region of the plug capillary tube is received so that a front end surface of the plug capillary tube resides within a volume defined by the annular sealing element; (d) wherein the plug housing is adapted to detachably connect to the bushing unit; (e) a pressure piece through which a rear portion of the annular sealing element extends, the pressure piece having a front end spaced apart from a front end wall of the annular sealing element and having a rearward end surface that faces away from the front end wall of the annular sealing element, the pressure piece is in position to abut a shoulder 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 the front end region of the plug capillary tube, the annular sealing element, and the pressure piece are 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 when 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 receptacle opening of the bushing unit and the plug housing is placed in the connected position, 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 wall of the annular sealing element against a floor wall of the capillary tube receptacle opening of the bushing unit.