Ferrule for making fingertight column connections in gas chromatography

A ferrule arrangement for use in sealing connections to gas chromatography columns, comprising:

• a generally tubular metal ferrule with a continuous smooth axial bore to receive a fracturable column with a protective coating, which ferrule has a forward part that tapers to a tip region of said ferrule;
• a generally tubular former having an axially extending bore with a counterbore that provides a socket portion to receive said ferrule and further having an internal conical surface that, after such receipt, engages said forward part of the ferrule, said internal conical surface formed in the bore immediately adjacent an inner end of the counterbore;
• and
• a portion on either or both of said ferrule and said former by which the ferrule and former may be moved together by application of finger force alone;
• wherein said taper and said internal conical surface exhibit relative taper angles and said tip region of said ferrule is sufficiently radially thin whereby said application of finger force alone (i) is adequate to move the ferrule axially into the former to cause said conical surface to engage the tip region of the ferrule and to deform the tip region into sealing engagement with said protective coating of the column, but (ii) does not break the column;
• and
• wherein the bore of the former is of greater diameter than the bore of the ferrule and the tip region of the ferrule at the tip thereof has a radial thickness between 0.05 and 0.15 mm so that the tip of the ferrule projects into the bore of the former and beyond said internal conical surface, and said internal conical surface engages the tip region behind the actual tip of the ferrule.