Patent ID: 7588683

Claim:
A column for liquid chromatography, said column adapted to contain a packing medium, said column comprising: a chamber for receiving said packing medium, said chamber defining an axial bore having a diameter; a first opening positioned in said chamber for passing liquid through said chamber; a first porous plug positioned overlying said first opening for retaining said medium within said chamber, said first porous plug having a diameter greater than said diameter of said axial bore; a second porous plug for retaining said medium within said chamber, said second porous plug being movable within said chamber, said second porous plug having a diameter greater than said diameter of said axial bore; a piston in facing relation with said second porous plug, said piston being axially movable within said axial bore of said chamber for compressing said second porous plug against said medium; a second opening, positioned in said piston, for passing liquid through said chamber; and a fitting rotatably mounted on an outer surface of said chamber and engaging said piston, said fitting being adjustably movable for axially moving said piston within said chamber.