Patent ID: 7638742

Claim:
A method of retrosealing an at least partly formed packaging container which comprises a tubular first packaging part of a sheet of thermoplastically coated packaging material comprised of at least one layer of an induction heatable material, the first packaging part having a first portion including an edge section and a second portion including an edge section, a first overlap joint being formed between said edge sections of the first and second portions, the packaging container also including a second packaging part which is adapted to be sealed to a first end of the first packaging part in a second overlap joint, the first and the second overlap joints intersecting one another, there being formed, at an intersection between the first and the second joints an intersection zone, and the method comprising retrosealing at least said intersection zone by disposing at least one induction heating device including at least one conductor at least against the intersection zone, inducing a current in the layer of induction heatable material and conducting a sufficiently large proportion of said induced current via the first portion of the first packaging part whose edge section abuts against the second packaging part in order that retrosealing take place between the first and second packaging parts at least in the intersection zone and for ensuring that an outside as well as an inside of the packaging container are not damaged by the retrosealing.