Cartridge type separation column and holder assembly for liquid chromatographs

In a liquid chromatograph (LC) system in which a liquid is delivered under pressure from a pump to an LC column, a replaceable column cartridge and holder assembly adapted for removal, shipment, and handling as a self-contained unit including an elongate cylindrical metal tube, a sorbant filling said tube, a pair of plastic seal plugs for closing the ends of said tube, each of said plugs being of T-shape in cross-section with a leg constructed to extend into a respective end of the tube and having a laterally extending end flange portion overlapping the tube at each end to its outer diameter, said tube, seal plugs and said sorbant together forming self-supporting replaceable LC cartridge, fittings for interconnecting the cartridge in the LC output line between the pump output and the LC detector system, each fitting having a cartridge receiving recess therein formed within the body of said fitting and so dimensioned as to receive the same in close fitting relation so that each recess extends at least over the flange portions of said plugs so that the latter totally confined within the recesses by their sidewalls and are axially confined between the cartridge tube and the floor of recess, means for supporting said cartridge and for yieldably urging the cartridge under pressure into sealing engagement between the fittings, the sealing surfaces comprising the floor of each recess, the tube ends, and the interposed seal plug flange, all of which are oriented in direct opposition to leakage forces, said means for urging the column into sealing engagement within said fittings including a holder having an effective length together with said fittings to extend somewhat less than the length of the column, and having threaded portions formed at each end thereof, cap nuts having an open end provided with an associated recess therein having threaded portions for engaging the threaded portions of each end of the holder, the other end of said nut being partially closed to form a cap having an aperture therethrough, said end fittings having a projection extending through the respective aperture and a body contained within said cap recess, and spring means interposed between at least one cap nut and associated end fitting for yieldably urging the latter into engagement with the interposed cartridge as the cap nuts are taken up against said spring means so that said cartridge is placed end to end compression by said holder, cap nuts, and interposed spring means.