Connector for capillary tubes having a tapered inner bore

An easily-assembled, heat-resistant capillary tube connector for releasably joining end portions of two capillary tubes in end-to-end fashion for use in chromatography without interrupting fluid flow or interfering with chromatographic results, comprising

• a cylindrical sleeve having an outside surface and an outside diameter,
• a bore in the sleeve extending between a sleeve first end portion with a first outer end and a sleeve second end portion with a second outer end,
• the bore having an inside surface and a center point,
• the first end portion of the sleeve having a first tapered inside surface which tapers to a smaller diameter near the center point of the sleeve,
• the first tapered inside surface of the sleeve being adapted for being contacted by a tip of an end portion of a first capillary tube to form a press-seal therewith,
• the second end portion of the sleeve having a second tapered inside surface which tapers to a smaller diameter near the center point of the bore,
• the second tapered inside surface of the sleeve being adapted for being contacted by a tip of an end portion of a second capillary tube to from a press-seal therewith,
• a first ferrule adapted to be mounted on the end portion of the first capillary tube and having a ferrule bore with an inside surface for contacting the outside surface of the first capillary tube to form a seal therewith, and having an outside surface for contacting the inside surface of the sleeve bore to form a seal with the inside surface of the sleeve,
• a second ferrule adapted to be mounted on the end portion of the second capillary tube and having a ferrule bore with an inside surface for contacting the outside surface of the second capillary tube to form a seal therewith, and having an outside surface for contacting the inside surface of the sleeve bore to form a seal therewith,
• a jacket surrounding and containing the sleeve and having a jacket first end and a jacket second end,
• a first adjustment screw means mounted on the jacket first end for pushing against the first ferrule to deform the ferrule into sealing contact with the outside surface of the first capillary tube and with the inside surface of the sleeve bore,
• a second adjustment screw means mounted on the jacket second end for pushing against the second ferrule to deform the ferrule into sealing contact with the outside surface of the second capillary tube and with the inside surface of the sleeve bore,
• whereby the pressure on the first ferrule may be adjusted individually and independently of the pressure on the second ferrule by rotating the first adjustment screw to form seals between the first ferrule and the first tube and between the first ferrule and the sleeve, and the pressure on the second ferrule may be adjusted individually and independently of the pressure on the first ferrule by rotating the second adjustment to form seals between the second ferrule and the second tube and between the second ferrule and the sleeve,
• said sleeve including
• a first chamber at an outer end of the sleeve bore with a larger diameter and an inside surface with a taper to a smaller diameter at an inner end of the first chamber,
• a second chamber at an outer end of the sleeve bore with a larger diameter and an inside surface with a taper to a smaller diameter at an inner end of the second chamber,
• the first ferrule being seated in the first chamber and having an outside surface with a taper to a smaller diameter at the inner end to match the flare of the first chamber,
• and the second ferrule being seated in the second chamber and having an outside surface with a taper to a smaller diameter at the inner end to match the flare of the second chamber,
• said jacket comprising
• a cup-shaped housing with a cylindrical sidewall extending from a housing end wall having a threaded hole which is smaller in diameter than the outer diameter of the sleeve to hold the sleeve in the jacket housing,
• the housing having an open top of larger diameter than the outside diameter of the sleeve so as to receive the sleeve into the housing,
• a cap removably mounted on the open top of the housing and having a sidewall extending from an end wall with a threaded hole which is smaller in diameter than the outer diameter of the sleeve to hold the sleeve in the jacket,
• said first adjustment screw means comprising a first adjustment screw with a stem for exerting pressure on the first ferrule, a threaded portion for threading into the threaded hole of the housing end wall, and a head for rotating the adjustment screw to adjust the pressure on the first ferrule,
• said second adjustment screw means comprising a second adjustment screw with a stem for exerting pressure on the second ferrule, a threaded portion for threading the second screw into the threaded hole of the cap, and a head for rotating the second screw to adjust the pressure on the second ferrule, and
• said jacket having visual means for inspecting the seals of the connector.

A method of sealingly connecting an end portion of a first capillary tube to an end portion of a second capillary tube, comprising the steps of providing

• an easily-assembled, heat-resistant capillary tube connector for releasably joining end portions of two capillary tubes in end-to-end fashion for use in chromatography without interrupting fluid flow or interfering with chromatographic results, comprising
• a cylindrical sleeve having an outside surface and an outside diameter,
• a bore in the sleeve extending between a sleeve first end portion with a first outer end and a sleeve second end portion with a second outer end,
• the bore having an inside surface and a center point,
• the first end portion of the sleeve having a first tapered inside surface which tapers to a smaller diameter near the center point of the sleeve,
• the first tapered inside surface of the sleeve being adapted for being contacted by a tip of an end portion of a first capillary tube to form a press-seal therewith,
• the second end portion of the sleeve having a second tapered inside surface which tapers to a smaller diameter near the center point of the sleeve,
• the second tapered inside surface of the sleeve being adapted for being contacted by a tip of an end portion of a second capillary tube to form a press-seal therewith,
• a first ferrule adapted to be mounted on the end portion of the first capillary tube and having a ferrule bore with an inside surface for contacting the outside surface of the first capillary tube to form a seal therewith, and having an outside surface for contacting the inside surface of the sleeve bore to form a seal with the inside surface of the sleeve,
• a second ferrule adapted to be mounted on the end portion of the second capillary tube and having a ferrule bore with an inside surface for contacting the outside surface of the second capillary tube to form a seal therewith, and having an outside surface for contacting the inside surface of the sleeve bore to form a seal therewith,
• a jacket surrounding and containing the sleeve and having a jacket first end and a jacket second end,
• a first adjustment screw means mounted on the jacket first end for pushing against the first ferrule to deform the ferrule into sealing contact with the outside surface of the first capillary tube and with the inside surface of the sleeve bore,
• a second adjustment screw means mounted on the jacket second end for pushing against the second ferrule to deform the ferrule into sealing contact with the outside surface of the second capillary tube and with the inside surface of the sleeve bore,
• whereby the pressure on the first ferrule may be adjusted individually and independently of the pressure on the second ferrule by rotating the first adjustment screw to form seals between the first ferrule and the first tube and between the first ferrule and the sleeve, and the pressure on the second ferrule may be adjusted individually and independently of the pressure on the first ferrule by rotating the second adjustment to form seals between the second ferrule and the second tube and between the second ferrule and the sleeve,
• said sleeve including
• a first chamber at an outer end of the sleeve bore with a larger diameter and an inside surface with a taper to a smaller diameter at an inner end of the first chamber,
• a second chamber at an outer end of the sleeve bore with a larger diameter and an inside surface with a taper to a smaller diameter at an inner end of the second chamber,
• the first ferrule being seated in the first chamber and having an outside surface with a taper to a smaller diameter at the inner end to match the flare of the first chamber,
• and the second ferrule being seated in the second chamber and having an outside surface with tpaer to a smaller diameter at the inner end to match the flare of the second chamber,
• said jacket comprising
• a cup-shaped housing with a cylindrical sidewall extending from a housing end wall having a threaded hole which is smaller in diameter than the outer diameter of the sleeve to hold the sleeve in the jacket housing,
• the housing having an open top of larger diameter than the outside diameter of the sleeve so as to receive the sleeve into the housing,
• a cap removably mounted on the open top of the housing and having a sidewall extending from an end wall with a threaded hole which is smaller in diameter than the outer diameter of the sleeve to hold the sleeve in the jacket,
• said first adjustment screw means comprising a first adjustment screw with a stem for exerting pressure on the first ferrule, a threaded portion for threading into the threaded hole of the housing end wall, and a head for rotating the adjustment screw to adjust the pressure on the first ferrule,
• said second adjustment screw means comprising a second adjustment screw with a stem for exerting pressure on the second ferrule, a threaded portion for threading the second screw into the threaded hole of the cap, and a head for rotating the second screw to adjust the pressure on the second ferrule, and
• said jacket having visual means for inspecting the seals,
• inserting the end portion of the first capillary tube through the first adjustment screw, through the threaded hole of the jacket housing end wall, through the first ferrule, and into the tapered inside surface of the sleeve in the housing to form a pres-seal between the tip of the capillary tube and the inner surface of the sleeve bore,
• inserting the end portion of the second capillary tube through the second adjustment screw, through the hole in the cap, and through the second ferrule and into the tapered inside surface of the sleeve to form a press-seal between the tip of the capillary tube and the inner surface of the sleeve bore,
• rotating the cap to mount it onto the open top of the jacket housing,
• independently rotating the first adjustment screw to adjust the pressure on the first ferrule to form a seal between the first ferrule and the first capillary tube and to form a seal between the first ferrule and the sleeve bore,
• independently rotating the second adjustment screw to adjust the pressure on the second ferrule to form a seal between the second ferrule and the second capillary tube and to form a seal between the second ferrule and the sleeve,
• and visually inspecting the seals.