SIMPLIFIED TRANSVERSAL INDUCTION SEALING DEVICE

Abstract

Disclosed embodiments relate to an induction sealing device for heat sealing packaging material for producing sealed packages of pourable food products. In some embodiments, the sealing device includes: an inductor device which interacts with said packaging material by means of at least one active surface; a flux-concentrating insert; and a supporting body made of heat-conducting material and housing said inductor device and said flux-concentrating insert, wherein said flux concentrating insert is made by a magnetic compound of a polymer and soft magnetic particles; and said flux concentrating insert interacts with said packaging material via at least one interactive surface.

Claims

1. An induction sealing device for heat sealing packaging material for producing sealed packages of pourable food products, said sealing device comprising: an inductor including at least one active surface configured to interact with said packaging material; a flux-concentrating insert; and a supporting body made at least partially of heat-conducting material and comprising at least one cavity housing said flux-concentrating insert, said inductor positioned in said at least one cavity and surrounded by said flux-concentrating insert without covering said at least one active surface, wherein said flux-concentrating insert comprises a magnetic compound of a polymer and soft magnetic particles, and wherein said flux-concentrating insert is configured to interact with said packaging material via at least one interactive surface.

2. The induction sealing device according to claim 1, wherein said at least one cavity is adapted and shaped as a mould for viscous non-cured magnetic compound and, wherein said flux-concentrating insert is moulded directly into said at least one cavity of said supporting body.

3. The induction sealing device according to claim 1, wherein said soft magnetic particles are selected from the group consisting of: ferrite, NiZn ferrite, FeSiAl, FeSiB and FeNi-alloys.

4. The induction sealing device according to claim 1, wherein said magnetic compound is electrically insulating.

5. The induction sealing device according to claim 1, wherein said magnetic compound is reinforced with a fiber structure so as to enhance its mechanical strength.

6. The induction sealing device according to claim 2, wherein said at least one cavity includes at least one circumferential recess adapted to lock a moulded flux-concentrating insert in said at least one cavity.

7. The induction sealing device according to claim 1, wherein said induction sealing device is a transversal induction sealing device.

8. The induction sealing device according to claim 1, wherein said supporting body is made of stainless steel.

9. The induction sealing device according to claim 7, further comprising a central cutting groove extending along a central transversal axis of said supporting body and an axis normal to the at least one active surface, wherein said inductor comprises two inductors positioned on both sides of said cutting groove, and wherein said cutting groove is configured to permit said packaging material to be cut.

10. The induction sealing device according to claim 9, wherein said cutting groove is formed in said supporting body, and wherein a plurality of cavities are formed on each side of said cutting groove.

11. The induction sealing device according to claim 1, wherein said at least one cavity includes an opening in which said at least one interactive surface of said flux-concentrating insert is located, wherein said opening has a cross sectional area that is smaller than a second cross sectional area in the at least one cavity positioned distal from said opening, and wherein said opening cross sectional area is parallel to said second cross sectional area.

12. The induction sealing device according to claim 1, wherein said inductor has-includes at least one recess extending at least in a direction parallel to said at least one interactive surface of said flux-concentrating insert, the at least one recess locking said inductor in said flux-concentrating insert.

13. The induction sealing device according to claim 1, wherein said at least one cavity includes a flat bottom side that prevents rotation of a said flux-concentrating insert.

14. An induction sealing device for heat sealing packaging material for producing sealed packages of pourable food products, said sealing device comprising: a housing made at least partially of heat-conducting material and comprising a plurality of cavities; a plurality of flux-concentrating inserts each positioned in a respective cavity of said plurality of cavities in said housing, each flux-concentrating insert comprising a magnetic compound of a polymer and soft magnetic particles, and each flux-concentrating insert configured to interact with said packaging material via at least one interactive surface; and a plurality of inductors each including at least one active surface configured to interact with said packaging material, each inductor positioned in a respective cavity of said plurality of cavities and surrounded in said respective cavity by a flux-concentrating insert without covering said at least one active surface.

15. The induction sealing device according to claim 14, further comprising a cutting groove formed in said housing and extending along a central transversal axis of said housing, said cutting groove configured to permit said packaging material to be cut, wherein at least two cavities of said plurality of cavities are positioned on both sides of said cutting groove, and wherein at least two inductors of said plurality of inductors are positioned in said at least two cavities.

16. The induction sealing device according to claim 14, wherein at least one of said plurality of cavities includes at least one circumferential recess adapted to lock a flux-concentrating insert in said cavity.

17. The induction sealing device according to claim 14, wherein at least one of said plurality of inductors includes at least one recess locking said inductor in a flux-concentrating insert.

18. The induction sealing device according to claim 14, wherein at least one of said plurality of cavities includes a flat bottom side that prevents rotation of a flux-concentrating insert positioned in said cavity.

19. The induction sealing device according to claim 14, wherein at least one of said plurality of cavities includes an opening in which said at least one interactive surface of a flux-concentrating insert is located, wherein said opening has a cross sectional area that is smaller than a second cross sectional area of a portion of said cavity distal from said opening, and wherein said opening cross sectional area is parallel to said second cross sectional area.

20. The induction sealing device according to claim 14, wherein said soft magnetic particles of said plurality of flux-concentrating inserts are selected from the group consisting of ferrite, NiZn ferrite, FeSiAl, FeSiB and FeNi-alloys.

Description

DESCRIPTION OF THE DRAWINGS

[0035] In the following the present invention will be described in greater detail together with the accompanying drawings, in which

[0036] FIG. 1 is cross sectional view of a transversal sealing device according to the prior art.

[0037] FIG. 2 is a cross sectional view of a transversal sealing device according to a first embodiment of the present invention.

[0038] FIG. 3 is a cross sectional view of a transversal sealing device according to a second embodiment of the present invention.

[0039] FIG. 4a-4c are cross sectional views of a transversal sealing device according to a third, fourth and fifth embodiment of the present invention.

[0040] FIG. 5 is a cross sectional view of a transversal sealing device according to a sixth embodiment of the present invention.

DETAILED DESCRIPTION

[0041] FIG. 1 is a cross sectional drawing of a transversal induction sealing device 15 according to the prior art. A supporting body 24 is housing a flux-concentrating insert 30′ which flux-concentrating insert 30′ houses inductor device 20, 21. The inductor device have active surfaces 25, 26 adapted to be pressed against a packing material surface (not shown) to induce current and thereby heat in a metal layer of the packing material during a sealing process. The inductor device 20, 21 and the flux-concentrating insert 30′ are locked to the supporting body by a moulded plastic member 19. The plastic member 19 will also have an outer surface that will be pressed against the packing material during a sealing operation. High pressures are exerted on the sealing device when in use, which will wear substantially on the, compared to the dimensions of the induction device, relatively thin plastic member. The result is that the plastic member often will crack, reducing the lifetime of the induction device.

[0042] FIG. 2 shows a cross sectional view of a transversal induction device 19 according to the present invention. A supporting body 24 has a cavity 4, in which cavity 4 inductor device 20, 21 are positioned. In the cavity 4 a flux-concentrating insert 30 is moulded around the inductions means 20, 21, without covering the active surfaces 25, 26 of the inductor device. The flux-concentrating insert has an interacting surface 31 that is in level with the active surface 25 of the inductor device 20, 21. The cavity has a circumferential recess 5 along a side wall for locking the moulded flux-concentrating insert 30 in the cavity. The flux-concentrating insert 30 is moulded by a magnetic compound of a polymer and soft magnetic particles (not shown), the polymer being made by polyamideor polyphenylene sulphide and the magnetic particles being ferrite, NiZn ferrite, FeSiAl, FeSiB or FeNi-alloys. Ni Zn ferrite is preferred. The moulded material may also be reinforced by e.g. glass fiber (not shown). A cutting groove 3 is formed in the flux-concentrating insert 30 to allow a packing material to be cut simultaneously with the sealing of a packing material on either side of the cutting groove 30. The cutting groove is formed during the moulding of the flux-concentrating insert by using a second part of the mould (not shown) placed in the volume that forms the cutting groove 3.

[0043] FIG. 3 shows a cross sectional view of a transversal induction device 19 according to a second embodiment of the present invention. A supporting body 24 has two cavities 4, in which cavities 4 inductor device 20, 21 are positioned. In each cavity 4 a flux-concentrating insert 30 is moulded around the respective inductions means 20, 21, without covering the active surfaces 25, 26 of the respective inductor device. The flux-concentrating insert has an interacting surface 31 that is in level with the active surface 25 of the inductor device 20, 21. Each cavity has a circumferential recess 5 along a side wall for locking the moulded flux-concentrating insert 30 in the cavity. The flux-concentrating insert 30 is moulded by a magnetic compound of a polymer and soft magnetic particles. A cutting groove 3 is formed in the supporting body 24 between the two cavities 4 to allow a packing material to be cut simultaneously with the sealing of a packing material on either side of the cutting groove 30. Each of the inductor device have a recess 7 for locking each inductor device to the respective moulded flux-concentrating insert 30.

[0044] FIG. 4a shows a cross sectional view of a transversal induction device 19 according to a third embodiment of the present invention. A supporting body 24 has two cavities 4, in which cavities 4 inductor device 20, 21 are positioned. In each cavity 4 a flux-concentrating insert 30 is moulded around the respective inductions means 20, without covering the active surfaces 26 of the respective inductor device. The flux-concentrating insert has an interacting surface 31 that is in level with the lower part of the active surface 25 of the inductor device 20. The flux-concentrating insert 30 is moulded by a magnetic compound of a polymer and soft magnetic particles. A cutting groove 3 is formed in the supporting body 24 between the two cavities 4 to allow a packing material to be cut simultaneously with the sealing of a packing material on either side of the cutting groove 30. Each of the inductor device have two recesses 7 for locking each inductor device to the respective moulded flux-concentrating insert 30. The opening cross section surface of each cavity 4 is smaller than the cross section surface further down in each cavity, locking the moulded flux-concentrating inserts 30 in the cavities 4.

[0045] FIG. 4b shows a cross sectional view of a transversal induction device 19 according to a fourth embodiment of the present invention, very similar to the third embodiment shown in FIG. 4a. In the fourth embodiment, the cavity has a flat bottom 8 to reduce tendencies of rotation of the moulded flux-concentrating insert 30.

[0046] FIG. 4c shows a cross sectional view of a transversal induction device 19 according to a fifth embodiment of the present invention, very similar to the third and fourth embodiments shown in FIG. 4a and FIG. 4b. In the fourth embodiment, the cavity has a more complex shape to reduce tendencies of rotation of the moulded flux-concentrating insert 30 and to optimize the flux-concentration.

[0047] FIG. 5 shows a cross sectional view of a transversal induction device 19 according to a sixth embodiment of the present invention. In this embodiment four cavities 4 are used. In each cavity 4 a flux-concentrating insert 30 is moulded around the respective inductions means 20. This embodiment is an example of how a so-called twin loop inductor can be combined with the present invention.

[0048] It is understood that other variations in the present invention are contemplated and in some instances, some features of the invention may be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly in a manner consistent with the scope of the invention.