Control unit for checking the integrity of tear-off closing devices applied to respective opening in strip packaging material for producing aseptic sealed packages of pourable food products

Abstract

A control unit ( ) interacting with a strip packaging material to which are applied, to close respective openings ( ) in the packaging material, a number of patch elements ( ) and a number of tear-off tongues ( ) heat sealed to respective patch elements ( ). To determine the integrity of the patch elements ( ), the unit has at least one contact surface ( ) at an operating electric potential (Va) and cooperating with the side of the packaging material ( ) having the patch elements ( ) to define one plate of a capacitor ( ), the other plate of which is defined by an aluminium film ( ) of the packaging material ( ), and the dielectric of which is defined by the heat-seal plastic material interposed between the plates; and a detecting circuit ( ) connected to the contact surface ( ) and to the aluminium film ( ) to detect an electric quantity related to variations in the dielectric strength of the dielectric of the capacitor ( ) and so determine the presence of any microholes in the patch elements ( ).