Patent ID: 6732496
Filing Date: 2004-05-11
Classification: B29C,B29K,B29L,B65B

Abstract:
A method of monitoring transverse sealing on a packaging unit comprising a sealing current source and at least one pair of jaws; at least a first of the jaws in said pair carrying an inductor; the method comprising the steps of:compressing a tube of packaging material, the packaging material having at least one electrically conducting layer, a heat-seal layer, and a layer of fibrous material which is filled with a pourable food product; supplying said inductor, during the compression step, with an electric current to generate a sealing current in said electrically conducting layer; measuring electric output quantities relative to said electric current, wherein the operation of measuring electric output quantities correlates with the power absorbed by said packaging material during the operation of supplying a sealing current; calculating both a load impedance recognized by said source and an energy of the current generated by said source, and; acquiring a difference in the distance between the jaws in said pair before and after sealing.