US 7,538,302 B2
Induction sealing device and method which may be used for producing packages of pourable food products
Claudio Ferrari, Fiorano Modenese (Italy); Antonio Melandri, Rubiera (Italy); Saquib Javed, Bagno (Italy); and Giorgio Galavotti, Concordia (Italy)
Assigned to Tetra Laval Holdings & Finance SA, Pully (Switzerland)
Appl. No. 10/551,206
PCT Filed Mar. 26, 2004, PCT No. PCT/EP2004/050385
§ 371(c)(1), (2), (4) Date Jun. 16, 2006,
PCT Pub. No. WO2004/085253, PCT Pub. Date Oct. 07, 2004.
Claims priority of application No. TO2003A0238 (IT), filed on Mar. 28, 2003.
Prior Publication US 2006/0242928 A1, Nov. 02, 2006
Int. Cl. H05B 6/14 (2006.01); H05B 6/00 (2006.01)
U.S. Cl. 219—633  [219/618] 14 Claims
OG exemplary drawing
 
1. An induction sealing device for producing packages of pourable food products by transversely sealing a tube of sheet packaging material comprising at least one layer of induction heatable material covered with plastic material, said sealing device comprising:
generating means for generating an alternating power signal, said alternating power signal having a current-voltage phase angle;
at least one inductor receiving the alternating power signal to induce a parasitic electric current in said layer and locally melt said plastic material to form a transverse seal; and
a matching circuit for achieving optimum power transfer between said generating means and said inductor;
wherein said matching circuit comprises an inductive-capacitive circuit, in which at least one inductive element is connected to at least one variable-capacitance capacitive element; the capacitance of the capacitive element being adjustable so that the current-voltage phase angle is close to zero.