induction heating sealing device, packaging machine, and method of forming a seal in a packaging material

摘要

induction heating sealing device, packaging machine, and method of forming a seal in a packaging material is described an induction heating sealing device (30) for forming a seal (14) in a packaging material ( 15, 11, 9) comprising an electrically conductive material and advancing in use along a first direction (a); the sealing device (30) comprises at least one inductive element (31); inductive element (31) comprises a first and second legs (79, 200; 72, 201) in which alternating currents pass in use in opposite directions; first leg (79, 200) is configured to induce, in use, a first portion (300) of an eddy current in an area (202) to be sealed of packaging material (15, 11, 9); the second leg (72; 201) faces the first leg (79, 200) along a second direction (c); the second leg (72, 201) is configured to induce in use a second portion (301) of eddy current in the area (202) to be sealed of packaging material (15,11,9); the first and second legs (79, 200; 72, 201) have a length in a third direction (b) parallel, in use, to the first direction (a) and transverse to the second direction (c); the first and second legs (79, 200; 72, 201) are asymmetric with respect to the third direction (b), so that the seal (14) is formed continuously along the second direction (c).