The invention relates to a pressure unit (1) for sealing a package (2) for a food product, comprising a conveyor (3) for transporting the package (2) through the pressure unit (1) in a travelling direction (d), a first rotatable pressure roller (11) and a first rotatable anvil roller (21). The first pressure roller (11) is arranged opposite to the first anvil roller (21) to form a first nip (4) for receiving and rotationally engage with a portion (5) of the package, and arranged downstream of the first pressure roller (11) and the first anvil roller (21) in the travelling direction, a second rotatable pressure roller (12) and a second rotatable anvil roller (22). The second pressure roller (12) is arranged opposite to the second anvil roller (22) to form a second nip (6) for receiving and rotationally engage with the portion (5) of the package. The first anvil roller (21) and the second anvil roller (22), respectively, has a smooth rim surface (25). The first pressure roller (11) comprises a first bulge (15) extending annularly around its rim surface (18), the second pressure roller (12) comprises a second bulge (16) extending annularly around its rim surface (19), and the first bulge (15) is offset in relation to the second bulge (16) in an axial direction (7) of said first pressure roller (11) and the second pressure roller (12).

An improved induction sealing device (300) is presented. The device (300) comprises a main body (302), a magnetic field concentrator (306) held in said main body (302) and a conductive element (304). One or several protrusions (314a, 314b) of said magnetic field concentrator (306) cooperate with one or several indentations or openings (312a, 312b) in said main body (302) such that said magnetic field concentrator (306) and said main body (302) is securely bonded together.

A welding head comprises a welding element (51) for welding a lid (1) to an opening device of a container (10). The welding head (43) further comprises a 5 compensating device (62) operable for compensating a misalignment between the welding element (51) and the lid (1), thereby centering the welding element (51) relative to the lid (1).

A method of controlling an inductive heating circuit, having a varying load, to seal a packaging material is provided. The method comprises generating AC power of at least two frequencies on at least one inductor in the inductive heating circuit; determining of the resulting phase shift in the inductive heating circuit from the current generated at the at least two frequencies; determining the impedance of the inductive heating circuit for each of the at least two frequencies; determining a load characteristics of the inductive heating circuit based on the relationship between the determined impedance and the determined phase shift; determining an impedance operating range; and selecting an AC output frequency for an induction power generator based on the load characteristics which results in the least amount of phase shift from a set ideal value and which is associated with an impedance that is within the impedance operating range.

An induction heating sealing device for induction welding of a packaging material for producing sealed packages of pourable food products in a package producing machine is provided. The packaging material has at least one layer of metallized film. The induction heating sealing device comprises an AC power source and an inductor coil connected to the AC power source and configured to induce eddy currents in the metallized film for inductive heating of the packaging material, wherein the AC power source is configured to generate a variable-voltage or current signal of a frequency higher than 1 MHz.

A method of controlling an inductive heating circuit, having a varying load, to seal a packaging material is provided. The method comprises generating AC power of at least two frequencies on at least one inductor in the inductive heating circuit; determining the resulting phase shift in the inductive heating circuit from the current generated at the at least two frequencies; determining the impedance of the inductive heating circuit for each of the at least two frequencies; determining a load characteristics of the inductive heating circuit based on the relationship between the determined impedance and the determined phase shift; determining an impedance operating range; and selecting an AC output frequency for an induction power generator based on the load characteristics which results in the least amount of phase shift from a set ideal value and which is associated with an impedance that is within the impedance operating range.

A method of sealing a container includes filling a receptacle with dispensable contents, coupling a closure to the receptacle to cover an open mouth of the receptacle, sealing the open mouth with a liner; engaging a pressure source to a sealing rib on a top face of the closure; and using a pressure source to force air through the openings and an air passage formed between a skirt of the closure and a neck of the receptacle.

The present invention relates to a device for sealing a packaging material (10), comprising at least one sealing installation (18) which comprises at least one coil core (24) which is surrounded by at least one coil (25), wherein the coil core (24) has at least one gap (32) through which packaging material peripheries (34, 36) to be sealed are guided, wherein at least one element (23) that conducts a magnetic flux is provided, said element (23) for influencing a region (22) of the packaging material peripheries (34, 36) to be heated being disposed so as to be adjacent to the packaging material peripheries (34, 36) to be sealed.

The invention relates to a sealing device (100) and a method for heat sealing packaging material for producing sealed packages. The invention also relates to a filling machine. The sealing device (100) comprises a first jaw (110) comprising an electromagnet (112), and a second jaw (120) comprising a magnetic element (122). The second jaw (120) is arranged opposite to the first jaw (110) to form a gap adapted to receive the packaging material, such that the first jaw (110) and the second jaw (120) are attracted to each other upon actuation of the electromagnet (112) to close the gap and clamp the packaging material between the first jaw (110) and the second jaw (120).

A device for inductive sealing of a plurality of plies of a laminate which comprises a carrier layer made of electrically non-conductive material, a sealing layer made of thermoplastic material and a metal layer disposed between the sealing layer and the carrier layer, includes two compressible sealing jaws, each fitted with an inductor embedded in a block of the sealing jaw. The block of each sealing jaw consists of a metallic material. A concentrator of each sealing jaw is composed of a plurality of partial pieces, wherein each partial piece consists of a material suitable for magnetic field concentration and all the partial pieces are electrically insulated from one another and with respect to the metal block. The inductor is disposed in a groove in the concentrator.