TUBE PLUGGING APPARATUS, ESPECIALLY FOR HEAT EXCHANGER TUBES

Tube-closing device with a tube plug having a plug casing with an enlargeable outer diameter for producing sealing surface pressure, and a plug core surrounded by the plug casing, the plug core and the plug casing being displaceable relative to one another, enlargement of the outer diameter of the plug casing being effected by a setting tool for the tube plug insertable into a respective tube to be closed, the setting tool being couplable with the plug core through the intermediary of a detachable holding rod and engageable with the plug casing through the intermediary of a support sleeve through which the holding rod extends, the setting tool having tensioning structure for producing an axial relative displacement of the holding rod and the support sleeve and thereby, of the plug casing and the plug core, includes coaxially disposed cuff rings mounted on the plug casing for effecting a seal between the plug casing and the plug core, the cuff rings having a starting, unstressed conical form with an outer diameter at most equal to the inner diameter of the tube to be closed, the cuff rings being flattenable out of the conical form thereof by the relative displacement of the plug casing and the plug core so that the outer diameter thereof is enlarged and they dig slightly into the wall of the tube to be closed.