Multilayer rod, sealing unit, package forming device, packaging machine, multilayer rod manufacturing method and induction sealing device manufacturing method

Abstract

A multi-layer rod (24) for an induction coil (22, 22') of a sealing unit (18) is described, comprising a metal layer (25) and a corrosion-resistant layer (26), the corrosion-resistant layer (26) including and / or formed from a nickel alloy.

Description

[Technical Field]

[0001] The present invention relates to a multi-layer rod for an induction coil, and more particularly to a multi-layer rod for a sealing unit for sealing multi-layer packaging materials.

[0002] Advantageously, the invention also relates to a sealing unit for a package forming machine for sealing tubes made from multi-layer packaging material for packages filled with pourable products, in particular pourable food products.

[0003] Advantageously, the invention also relates to a package-forming device for a packaging machine for forming packages filled with pourable products, in particular pourable food products.

[0004] Advantageously, the present invention also relates to a packaging machine for forming packages filled with pourable products, in particular pourable food products.

[0005] Advantageously, the present invention also relates to a method for manufacturing a multi-layer rod for an induction coil of a sealing device for sealing multi-layer packaging materials.

[0006] Advantageously, the present invention also relates to a method of manufacturing an induction sealing device including an induction coil comprising and / or formed from multi-layered rods. [Background technology]

[0007] As is well known, many liquid or pourable food products, such as fruit juices, UHT (ultra-high temperature processed) drinks, milk, wine, tomato sauce, etc., are sold in packages made from paper or carton-based packaging materials. A typical example of this type of package is the parallelepiped-shaped package known as Tetra Brik Aseptic®, which is made by folding and sealing a web of laminated packaging material.

[0008] The packaging material has a multi-layer structure consisting essentially of a base layer of fibrous material, e.g., paper or carton, covered on both sides with layers of heat-sealable polymeric material, e.g., polyethylene. In the case of aseptic packages for long-life products, e.g., UHT milk, where storage and distribution take place at ambient temperatures, the packaging material usually comprises a layer of gas- and light-tight material, e.g., aluminum foil, which is superimposed on a layer of heat-sealable polymeric material and covered with another layer of heat-sealable polymeric material that ultimately forms the inner surface of the package that comes into contact with the food product.

[0009] Packages formed from the aforementioned multilayer packaging material are typically produced using fully automated packaging machines, such as the Tetra Pak® A3 / Flex filling machine, that employ form-fill-seal technology. More specifically, the manufacturing process for this type of packaging material involves advancing a web of packaging material through a sterilization unit where it is sterilized at a sterilization station, and then into an isolation chamber that encloses a sterile environment where the sterilized web of packaging material is maintained and advanced. While advancing through the enclosed aseptic chamber, the packaging material web is longitudinally folded and sealed at a tube-forming station to form a tube. The resulting tube is continuously fed along the forward direction, filled with a sterilized or aseptically processed pourable product, particularly a pourable food product, and gripped at equally spaced cross sections by respective operating groups of the package-forming device. More specifically, the operating groups act on the tube in a cyclical sequence, heat-sealing the packaging material in the tube to form cushion-like packages connected to each other by respective transverse seal bands extending transversely to the forward direction. The cushion-like packages are separated by transversely cutting each seal band. The package is then transported to a final folding station where it is mechanically folded into the finished parallelepiped shape.

[0010] Conventionally, packages are heat-sealed via ultrasonic welding or induction heating processes. In a packaging machine using induction heat sealing, each operating group includes a sealing unit with an induction sealing device that essentially includes an induction coil powered by a high-frequency current generator. More specifically, the induction coil is made of a conductive material, and the generated electromagnetic field interacts with the aluminum foil layer in the packaging material to induce eddy currents, heating the polymer material to the required sealing temperature.

[0011] A known induction seal device is disclosed in European Patent Application EP 2984903A1 and includes an induction coil made from a multi-layer rod including a conductive layer made of pure silver and a corrosion-resistant layer made of a silver-palladium alloy. In particular, the induction coil has one or more sealing surfaces defined by at least a portion of the corrosion-resistant layer, and is partially enclosed within a support such that the sealing surfaces are exposed from the support of the induction seal device for cooperation with a tube during formation of a package. Summary of the Invention [Problem to be solved by the invention]

[0012] Although known induction sealing devices function satisfactorily, the use of silver-palladium alloys to manufacture the corrosion-resistant layers of multi-layer rods involves significant costs.

[0013] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a multi-layer rod for induction coils of a sealing unit that includes a corrosion-resistant layer while reducing costs.

[0014] Advantageously, it is another object of the present invention to provide an improved sealing unit for a package forming machine.

[0015] Advantageously, another object of the present invention is to provide an improved package forming apparatus for a packaging machine.

[0016] Advantageously, it is also an object of the present invention to provide an improved packaging machine.

[0017] Advantageously, another object of the present invention is to provide a method for manufacturing a multi-layer rod for an induction coil of a sealing device, the multi-layer rod including a corrosion resistant layer, which is provided at a reduced cost.

[0018] Advantageously, another object of the present invention is to provide a method of manufacturing an induction seal device comprising and / or formed from a multi-layer induction coil rod and including a corrosion resistant layer. [Means for solving the problem]

[0019] According to the present invention, a multi-layer rod as claimed in claim 1 is provided.

[0020] Preferred, non-limiting embodiments of the multilayer rod are set forth in the claims that depend directly and indirectly from claim 1.

[0021] According to the present invention, there is also provided a sealing unit as set forth in claim 9.

[0022] Preferred, non-limiting embodiments of the sealing unit are set forth in the claims that depend directly and indirectly from claim 9.

[0023] According to the present invention, there is also provided a package forming apparatus as set forth in claim 12.

[0024] According to the present invention there is also provided a packaging machine as set forth in claim 13.

[0025] According to the present invention, there is also provided a method for producing a multi-layer rod as set forth in claim 14.

[0026] According to the present invention, there is also provided a method for manufacturing an induction sealing device as set forth in claim 15.

[0027] Two non-limiting embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram of a packaging machine for forming packages, the packaging machine having a package forming device. [Figure 2] 2 is a schematic perspective view showing details of the package forming apparatus of FIG. 1, with parts removed for clarity; FIG. [Figure 3] 1 is a perspective view of an induction sealing device of a package forming apparatus according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a perspective and partially exploded view of the induction seal device of FIG. 3 with parts removed for clarity. [Figure 5] FIG. 4 is a cross-sectional view of the induction sealing device of FIG. 3. [Figure 6] 4 is a perspective view of a detail of the induction seal device of FIG. 3, with parts removed for clarity, and an enlarged view of the detail. [Figure 7] FIG. 5 is a perspective view showing details of an induction sealing device according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a side view showing details of the induction seal device shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0029] Number 1 indicates as a whole a packaging machine for producing sealed packages 2 of pourable products, in particular pourable food products, such as milk, milk drinks, yogurt, yogurt drinks, fruit juices, wine, tomato sauce, milky liquids, pulp-containing drinks, salt, sugar, etc.

[0030] More particularly, the packaging machine 1 may be configured to produce packages 2 from multi-layer packaging material that preferably has heat-sealing properties (i.e., parts of the multi-layer packaging material can be sealed to each other using heat, and advantageously also using pressure).

[0031] More particularly, the multi-layer packaging material may comprise at least two layers of heat-sealable polymeric material, such as polyethylene, and at least one layer of fibrous material, such as paper or cardboard, interposed between the at least two layers of heat-sealable polymeric material. Preferably, one of the layers of heat-sealable polymeric material has a surface that defines the inner surface of the package 2 in at least partial contact with the pourable product.

[0032] Furthermore, the multilayer packaging material may include a gas and light barrier material layer, which preferably includes and / or consists of a metal material, disposed between one of the layers of heat-sealable polymer material and the layer of fibrous material. Preferably, the gas and light barrier material layer may include aluminum foil.

[0033] Preferably, the multilayer packaging material may include a metal layer that is susceptible to induction heating, and more preferably, the metal layer may function as a gas and light barrier material layer.

[0034] Most preferably, the metal layer is an aluminum layer.

[0035] Preferably, the packaging material may comprise a further layer of heat-sealable polymeric material disposed between the layer of gas and light barrier material and the layer of fibrous material.

[0036] Furthermore, the multi-layer packaging material may be provided in the form of a web 3 .

[0037] In particular, the packaging machine 1 may be configured to produce the packages 2 by forming a tube 4 from the web 3, sealing the tube 4 longitudinally, filling the tube 4 with a pourable product, and sealing and cutting the tube 4 transversely.

[0038] According to some possible non-limiting embodiments, each package 2 may extend along a longitudinal axis A.

[0039] According to some possible embodiments, each package 2 may comprise at least a first transverse sealing band 5 and preferably a second transverse sealing band, arranged at opposite ends of the package 2 and preferably extending transversely to the axis A.

[0040] Preferably, the first transverse seal band 5 of each package 2 may define an upper transverse seal band and the respective second transverse seal band may define a lower transverse seal band.

[0041] Furthermore, each package 2 may include a longitudinally extending seam 6. Preferentially, each first transverse sealing band 5 and / or each second transverse sealing band may be arranged transversely, preferentially perpendicularly, to the respective seam 6.

[0042] 1, packaging machine 1 may include a package forming apparatus 7 configured to transversely seal tube 4 to obtain package 2. Preferably, package forming apparatus 7 may be configured to transversely cut and at least partially shape tube 4.

[0043] Furthermore, the packaging machine 1 - a conveying device 8 configured to advance the web 3 along a web advancement path P, preferably to a tube forming station where the web 3 is formed into a tube 4, and configured to advance the tube 4 along a tube advancement path Q; - a tube forming and sealing device 9 configured to fold the advancing web 3 into a tube 4 and seal the tube 4 longitudinally; a filling device 10 for filling the tubes 4 with a pourable product; may also be provided.

[0044] The packaging machine 1 may further comprise an isolation chamber 11 which preferably encloses a sterile environment. Preferably, the sterile environment may comprise a controlled atmosphere.

[0045] Preferably, the tube forming and sealing device 9 is disposed at least partially within the isolation chamber 11 and is configured to collapse and longitudinally seal the tube 4 within the isolation chamber 11 .

[0046] Furthermore, the packaging machine 1 may be provided with a sterilization unit (not shown) configured to sterilize the advancing web 3, and preferably the sterilization unit may be located along the web advancement path P upstream of the tube forming and sealing device 9.

[0047] More particularly, the conveying device 8 may be configured to advance the tube 4 and partially formed tube 4 along a tube advancement path Q, preferably from the tube forming and sealing device 9 to the package forming device 7.

[0048] In this specification, the expression "partially formed tube" is intended to mean any configuration of the web 3 obtained from the start of the folding process of the web 3 carried out by the tube forming and sealing device 9 until the formation of the structure of the tube 4. In other words, the partially formed tube 4 is the result of gradually folding the web 3 to obtain the tube 4, preferably by overlapping the longitudinal ends of the web 3 with each other.

[0049] According to some possible non-limiting embodiments, the tube forming and sealing apparatus 9 may be arranged such that the tube 4 has a vertical orientation. Preferably, the tube 4 may extend along a longitudinal axis B parallel to the axis A.

[0050] Further, the tube forming and sealing device 9 may comprise at least two forming ring assemblies 12 preferentially disposed within the isolation chamber 11 and configured to cooperate to gradually fold the web 3 into the tube 4 by overlapping the ends of the web 3 with one another, thereby forming the seam portion 6.

[0051] Furthermore, the tube forming and sealing device 9 may comprise a sealing head 13 preferentially located within the isolation chamber 11 and configured to seal the tube 4 longitudinally, preferably along the seam 6.

[0052] Additionally, the tube forming and sealing apparatus 9 may include a pressure assembly configured to apply a mechanical force to the seam 6 to ensure that the tube 4 is sealed along the seam 6 .

[0053] Preferably, the filling device 10 may comprise a filling pipe 14 configured to direct the pourable product into the tube 4. Preferably, the filling pipe 14 may be at least partially disposed within the tube 4 while delivering the pourable product into the tube 4.

[0054] 1 and 2, the package forming apparatus 7 may include at least one, or preferably a plurality of, manipulation assemblies 15 (partially shown in FIG. 2 to the extent necessary for an understanding of the invention), each configured to transversely seal the tube 4. Preferably, each manipulation assembly 15 may be configured to transversely cut and at least partially shape the tube 4.

[0055] The package forming apparatus 7 may further include a transport unit (not shown) configured to advance the manipulation assembly 15. Preferably, the package forming apparatus 7 may be configured to control the manipulation assembly 15 and the transport unit to transversely seal and cut the tube 4 along equally spaced transverse cross sections, thereby forming respective first transverse seal bands 5 and / or respective transverse second seal bands.

[0056] More particularly, and with particular reference to FIG. 2 , each manipulation assembly 15 may include at least a first manipulation group 16 and a second manipulation group 17 configured to cooperate with one another to at least transversely seal and preferably cut and at least partially form the tube 4 .

[0057] According to some preferred non-limiting embodiments, the transport unit may be configured to advance a first operating group 16 along a first advancement path and advance a second operating group 17 along a second advancement path.

[0058] Furthermore, each first operating group 16 and each second operating group 17 may be configured to cooperate with each other to form the package 2 as they advance along the respective operating sections of the first advancement path and the second advancement path.

[0059] Furthermore, each first forward path and each second forward path may comprise a return section that allows the first operating group 16 and the second operating group 17 to return to the respective operating section.

[0060] Furthermore, each operating assembly 15 comprises at least one sealing unit 18 configured to seal the tube 4 laterally, thereby preferentially forming a respective main sealing band extending transversely to the axis B.

[0061] Preferably, each manipulation assembly 15 further comprises at least one cutting unit (not shown) configured to cut the tube 4 transversely.

[0062] In particular, each cutting unit may be configured to cut the tube 4 transversely after the tube 4 has been sealed by the respective sealing unit 18 .

[0063] More preferably, each cutting unit may be configured to cut a respective main sealing band, thereby preferentially forming a respective first transverse sealing band 5 and a respective second transverse sealing band. In other words, each main sealing band comprises a first transverse sealing band 5 and a second transverse sealing band. More specifically, each transverse main sealing band may comprise a first transverse sealing band 5 of a first package 2 and a second transverse sealing band of a second package 2, the second package 2 being disposed downstream of the first package 2 along the tube advance path Q.

[0064] More particularly, each sealing unit 18 may comprise an induction sealing device 19 configured to generate an electromagnetic field, preferably configured to interact with and / or heat the metal layer.

[0065] Additionally, each sealing device 18 may include a counter-seal element 20 configured to cooperate with the respective induction sealing device 19 to seal the tube 4 .

[0066] Preferably, each induction seal device 19 and each counter-seal element 20 may be configured to form a respective primary seal band. More specifically, each induction seal device 19 and each counter-seal element 20 may be configured to engage the tube 4 from opposite sides thereof.

[0067] Preferably, the first operating groups 16 may comprise respective induction sealing devices 19 and the second operating groups 17 may comprise respective counter-seal elements 20 .

[0068] More specifically, each induction sealing device 19 and each counter-seal element 20 may be configured to laterally compress and laterally seal at least the tube 4 as the tube 4 advances along the tube advance path Q and a portion of the tube 4 is positioned between the partially sealed package 2. As used herein, the expression "partially sealed package" refers to any configuration of the package 2 while still being part of the tube 4 and having the first transverse seal band 5 already formed.

[0069] 3-5, each induction sealing device 19 comprises an induction coil 22 configured to generate an electromagnetic field, preferably to induce an alternating current in the metal layer of the multi-layer packaging material, for inductively heating the metal layer. Preferably, each induction sealing device 19 comprises a housing 21, and the induction coil 22 is at least partially disposed within and / or enclosed within the housing 21.

[0070] Preferably, the housing 21 includes at least one main seal 23 formed from a polymer, and the induction coil 22 is at least partially disposed within and / or sealed within the main seal 23.

[0071] According to certain preferred, non-limiting embodiments of the present invention, induction coil 22 comprises and / or is composed of multi-layered rods 24 .

[0072] Advantageously, as illustrated in Figure 6, the multi-layer rod 24 comprises and / or consists of a metal layer 25 and a corrosion-resistant layer 26. Preferably, the metal layer 25 may include and / or consist of silver.

[0073] More specifically, the respective metal layers 25 of each induction coil 22 serve to generate the electromagnetic fields necessary for the induction heating process, while the respective corrosion-resistant layers 26 serve as protective layers that allow for positioning of portions of the induction coil 22 in corrosive environments, particularly those that would corrode the metal layers 25.

[0074] More specifically, the corrosion-resistant layer 26 may include a connecting surface 26a disposed on the mounting surface 25a of the metal layer 25. Preferably, the mounting surface 25a and the connecting surface 26a may be in direct contact with each other.

[0075] According to certain preferred, non-limiting embodiments of the present invention, mounting surface 25a and connecting surface 26a may be brazed to one another.

[0076] According to certain preferred, non-limiting embodiments of the present invention, the corrosion-resistant layer 26 may be comprised of a nickel alloy. Advantageously, the nickel alloy may be a nickel-molybdenum-chromium alloy. In other words, the corrosion-resistant layer 26 may include a nickel-molybdenum-chromium alloy.

[0077] More particularly, the corrosion resistant layer 26 may be a nickel alloy, more preferably a nickel-molybdenum-chromium alloy, containing at least 40% by weight of nickel and / or less than 60% by weight of nickel. In particular, the nickel alloy (or nickel-molybdenum-chromium alloy) may contain at least 45% by weight of nickel and / or less than 55% by weight of nickel.

[0078] The nickel alloy, preferably the nickel-molybdenum-chromium alloy, may further comprise at least 10 wt. % molybdenum and / or less than 20 wt. % molybdenum. In particular, the nickel alloy (or nickel-molybdenum-chromium alloy) may comprise at least 15 wt. % molybdenum and / or less than 17 wt. % molybdenum.

[0079] Furthermore, the nickel alloy, preferably the nickel-molybdenum-chromium alloy, may contain at least 10 wt. % chromium and / or less than 20 wt. % chromium. In particular, the nickel alloy (or nickel-molybdenum-chromium alloy) may contain at least 14.5 wt. % chromium and / or less than 16.5 wt. % chromium.

[0080] According to some possible non-limiting embodiments, the nickel alloy, preferably the nickel-molybdenum-chromium alloy, may further include iron. In particular, the nickel alloy, preferably the nickel-molybdenum-chromium alloy, may include at least 2 wt. % iron and / or less than 8 wt. % iron, preferably at least 4 wt. % iron and / or less than 7 wt. % iron.

[0081] According to some possible non-limiting embodiments, the nickel alloy, preferably the nickel-molybdenum-chromium alloy, may include tungsten. In particular, the nickel alloy, preferably the nickel-molybdenum-chromium alloy, may include 2% to less than 8% tungsten by weight, preferably at least 3.0% tungsten and / or less than 4.5% tungsten by weight.

[0082] Furthermore, the nickel alloy, preferably the nickel-molybdenum-chromium alloy, may contain trace amounts (low amounts, i.e., less than 5 wt. %, preferably less than 2 wt. % or less than 1 wt. %) of additional elements. Preferably, such additional elements may be selected from the list consisting of carbon, manganese, phosphorus, silicon, copper, sulfur, and vanadium. In particular, the nickel alloy may contain one or more of the following additional elements in trace amounts: - less than 0.01% carbon; - less than 1% manganese; - less than 0.04% phosphorus; - less than 0.08% silicon; - less than 2.5% copper; - less than 0.03% sulfur; - Less than 0.35% vanadium.

[0083] With particular reference to Figures 3 and 4, the induction coil 22 may preferably comprise a first induction bar 22a and a second induction bar 22b, both of which preferably extend parallel to each other in an at least partially linear manner along their respective longitudinal axes C.

[0084] More preferably, as shown in FIG. 4, the induction coil 22 may also include a curved portion 22c connecting the first induction bar 22a and the second induction bar 22b to each other.

[0085] Preferably, induction coil 22 may further include at least a first outer portion 27 and a second outer portion 28, preferably spaced apart, both protruding from housing 21, as shown in Figure 5. More specifically, first outer portion 27 and second outer portion 28 may be parallel to each other.

[0086] More preferably, the first outer portion 27 and the second outer portion 28 may at least partially define and / or constitute the respective outer surfaces of the induction sealing device 19 and / or the sealing unit 18. Even more preferably, the first guide bar 22a may comprise the first outer portion 27 and the second guide bar 22b may comprise the second outer portion 28.

[0087] More specifically, first outer portion 27 and second outer portion 25 may be defined by respective portions of corrosion-resistant layer 26 and configured to be exposed to an external corrosive environment. More specifically, induction coil 22 may be disposed within housing 21 and / or enclosed within housing 21, preferably enclosed within main encapsulation portion 23, such that metal layer 25 is completely enclosed within housing 21 and covered by corrosion-resistant layer 26.

[0088] Furthermore, the metal layers 25 are advantageously not in contact with the external corrosive environment. In other words, the corrosion-resistant layer 26 of each induction coil 22 serves to protect the respective metal layers 25, which have the necessary conductive properties to enable the generation of an electromagnetic field.

[0089] Furthermore, each induction coil 22 may comprise a connection group 30 configured to connect the induction coil 22 to a power supply group (not shown) of the package forming device 7, preferentially to a power supply group of each sealing unit 18, the power supply group being configured to apply an alternating current to each induction coil 22.

[0090] Preferably, the connection group 30 may comprise a first connection element 30a and a second connection element 30b that may be connected and / or coupled to a first end 31 and a second end 32 of the induction coil 22, respectively.

[0091] More specifically, the connecting element 30a and the second connecting element 30b may be connected and / or coupled to the first guide bar 22a and the second guide bar 22b, respectively, as shown in FIG.

[0092] According to certain preferred, non-limiting embodiments of the present invention, each induction sealing device 19 may include at least one groove 33 configured to preferentially receive a cutting element (not shown) of a cutting unit, more preferably a cutting edge (not shown) of the cutting element.

[0093] Preferably, the housing 21 may be provided with respective grooves 33, as shown in FIGS.

[0094] More specifically, the groove 33 may be provided between the first guide bar 22a and the second guide bar 22b.

[0095] In use, the packaging machine 1 produces packages 2 filled with a pourable product.

[0096] More specifically, a conveying device 8 advances the web 3 along a web advancement path P to a forming station, and a tube forming and sealing device 9 forms a tube 4 from the advancing web 3 and longitudinally seals the tube 4. A filling device 10 then fills the tube 4 with a pourable product, and a package forming device 7 at least partially forms, transversely seals, and transversely cuts the tube 4 to obtain packages 2. Note that the transverse sealing is performed transversely to the axis B.

[0097] More specifically, when package forming apparatus 7 is in operation, manipulating assembly 15 transversely seals and cuts tube 4, preferably through each main sealing band, to obtain each filled package 2. Preferentially and additionally, manipulating assembly 15 at least partially forms tube 4.

[0098] More specifically, during the transverse sealing operation, the induction sealing device 19 generates an electromagnetic field which interacts with the metal to heat the metal layer, thereby again fusing the layers of polymeric material together.

[0099] More particularly, the electromagnetic field is controlled by providing power, preferably via a power supply unit, induction coil 22 .

[0100] 7 and 8, numeral 22' denotes an alternative embodiment of an induction coil according to the present invention; induction coil 22' is similar to induction coil 22, and the following description will be limited to the differences between the two, and the same references will be used wherever possible for identical or corresponding parts.

[0101] In particular, the induction coil 22' may include a first pair of induction bars 34a, 34b and a second pair of induction bars 35a, 35b.

[0102] More specifically, the first and second pairs of guide bars 34a, 34b, 35a, 35b may extend linearly parallel to each other along respective axes C.

[0103] More specifically, the induction coil 22′ may further include a first curved portion 34c connecting the first set of induction bars 34a, 34b to each other, and a second curved portion 35c connecting the second set of induction bars 35a, 35b to each other.

[0104] Furthermore, the induction coil 22', preferably each connection group 30, may comprise a third (conductive) curved portion 34d connecting each pair of induction bars 34b, 35b to one another.

[0105] Furthermore, the first connection element 30a may be connected and / or coupled to one guide bar of the first pair of guide bars 34a, 34b, while the second connection element 30b may be connected and / or coupled to one guide bar of the second pair of guide bars 35a, 35b.

[0106] As shown in the example of Figures 7 and 8 of an alternative embodiment of the present invention, the first connection element 30a is connected to guide bar 34a of the first pair of guide bars, and the second connection element 30b is connected to guide bar 35a of the second pair of guide bars.

[0107] Furthermore, the connection group 30 may include an electrical insulating element 36, preferably an electrical insulating sheet of an electrical insulating material, disposed between at least a portion of the first and second connection elements 30 a, 30 b. In particular, the insulating element 36 may be disposed adjacent to the first connection element 30 a and the second connection element 30 b.

[0108] Furthermore, each groove 33 may be provided between a respective first and second pair of guide bars 34a, 34b, 35a, 35b.

[0109] The operation of the packaging machine 1 is similar regardless of whether the induction sealing device 20 is equipped with the induction coil 22 or the induction coil 22', so reference is made to the above description for the operation of the packaging machine 1 when the induction sealing device 20 has the induction coil 22'.

[0110] According to another aspect of the present invention, a method for making at least one multi-layer rod 24 is also disclosed.

[0111] More particularly, the method comprises: - providing metal sheets, preferentially silver sheets, and nickel alloy sheets, preferentially nickel-molybdenum-chromium alloy sheets, preferentially nickel alloy sheets, having the properties disclosed above; - brazing together metal plates, in particular silver plates and nickel alloy plates, in particular nickel-molybdenum-chromium alloy plates, to obtain a multilayer plate; At least one of the following is provided.

[0112] Preferably, the brazing step is carried out after the providing step.

[0113] Furthermore, the method may comprise the step of arranging the metal plate and the nickel alloy plate on top of each other. Preferably, the arranging step may be performed after the providing step and before the brazing step.

[0114] Additionally, the method may comprise a cutting step in which the multilayer board is cut to obtain one or more multilayer rods 24. Preferably, the cutting step is repeated to obtain a plurality of multilayer rods 24.

[0115] According to a further aspect of the present invention, a method of manufacturing at least one induction sealing device 19 having an induction coil 22 or an induction coil 22' is also disclosed.

[0116] More particularly, the method comprises: forming, during which the multi-layer rod 24 is formed into the induction coil 22 or 22'; - encapsulating the induction coil 22 or 22' while it is encapsulated and / or placed in the housing 21; At least one of the following is provided.

[0117] Preferably, the encapsulating step may be carried out after the forming step.

[0118] More particularly, the forming step includes: - bending at least one multilayer rod 24 into an induction coil 22, preferably while forming at least the induction bars 22a, 22b and the curved portion 22c of the induction coil 22; - soldering, during which the connection group 30 is soldered to the induction coil 22; may also be provided.

[0119] In the case of induction coil 22′, the step of forming induction coil 22′ may include a bending substep of bending a first multi-layered rod 24 to at least preferentially form induction bars 34a, 34b and curved portions 34c, 34d, and bending a second multi-layered rod 24 to at least preferentially form induction bars 35a, 35b and curved portion 35c.

[0120] Additionally, the step of forming the induction coil 22' may include the sub-step of joining the curved portion 34d to the induction bar 35b.

[0121] Preferably, the bonding substep is carried out after the providing step.

[0122] More specifically, during the soldering step, the first connection element 30a and the second connection element 30b are soldered to the first induction bar 22a and the second induction bar 22b of the induction coil 22 or the induction bar 34a and the induction bar 35a of the induction coil 22', respectively.

[0123] Preferably, the soldering step is carried out after the bending sub-step.

[0124] The encapsulation step is - placing the induction coil 22 or the induction coil 22' in a mould having and / or defining at least the shape of the housing 21; - injecting molten polymer into the mold so that the metal layer 25 of the induction coil 22 or of the induction coil 22' is completely immersed in the molten polymer and so that at least the remaining part of the corrosion-resistant layer 26 is not immersed in the molten polymer; may also be provided.

[0125] Furthermore, the method comprises: - cooling the molten polymer; - ejecting the solidified molten polymer partially encapsulating the induction coil 22 or induction coil 22' from the mold; may also be provided.

[0126] Preferably, the step of discharging may be carried out after the step of cooling.

[0127] The advantages of the packaging machine 1 and / or package forming device 7 and / or sealing unit 18 and / or induction coil 22 and / or induction coil 22' and / or multi-layer rod 24 according to the present invention will be clear from the above description.

[0128] In particular, nickel alloys, preferably nickel-molybdenum-chromium alloys, can be used to obtain high corrosion resistance while keeping costs down.

[0129] Furthermore, this allows the induction coil 22 or induction coil 22' to be provided with the required corrosion resistance at a reduced cost.

[0130] Furthermore, this manufacturing method allows for easy and cost-effective production of multi-layer rods 24 and / or induction coils 22 and / or induction coils 22'.

[0131] However, changes may be made to the packaging machine 1 and / or package forming device 7 and / or sealing unit 18 and / or multi-layer rod 24 described herein without departing from the scope of protection defined in the appended claims.

Claims

1. A multi-layer rod (24) for an induction coil (22, 22') of a sealing unit (18), comprising: The multilayer rod (24) comprises a metal layer (25) and a corrosion-resistant layer (26), the corrosion-resistant layer (26) comprises and / or consists of a nickel alloy; Multilayer rod (24).

2. The nickel alloy comprises at least 40% by weight of nickel and / or less than 60% by weight of nickel. The multi-layer rod of claim 1 .

3. the nickel alloy comprises at least 10 wt. % molybdenum and / or less than 20 wt. % molybdenum; 3. A multilayer rod according to claim 1 or 2.

4. The nickel alloy contains at least 10 wt. % chromium and / or less than 20 wt. % chromium. A multilayer rod according to any one of claims 1 to 3.

5. the nickel alloy contains at least 2 wt.% iron and / or less than 8 wt.% iron and / or 2 wt.% tungsten and / or less than 8 wt.% tungsten, A multilayer rod according to any one of claims 1 to 4.

6. The nickel alloy includes nickel, chromium, molybdenum, iron, and tungsten. A multilayer rod according to any one of claims 1 to 5.

7. The nickel alloy is at least 40% by weight but less than 60% by weight nickel; at least 10 wt. % but less than 20 wt. % molybdenum; 10% by weight or more and less than 20% by weight of chromium; 2% by weight or more and less than 8% by weight of iron; 2% by weight or more and less than 8% by weight tungsten; Including, The multi-layer rod of claim 6.

8. The corrosion-resistant layer (26) has a connecting surface (26a), the metal layer (25) has an attachment surface (25a), the connecting surface (26a) is disposed on the attachment surface (25a), and the connecting surface (26a) and the attachment surface (25a) are brazed to each other. A multilayer rod according to any one of claims 1 to 7.

9. The metal layer (25) comprises and / or consists of silver; A multilayer rod according to any one of claims 1 to 8.

10. A sealing unit (18) for sealing multi-layer packaging material, comprising an induction sealing device (19) configured to generate an electromagnetic field, The induction sealing device (19) comprises at least an induction coil (22, 22') comprising a multilayer rod (24) according to any one of claims 1 to 9 and / or an induction coil (22, 22') formed from a multilayer rod (24) according to any one of claims 1 to 9. Seal unit (18).

11. The seal unit (18) comprises a housing (21); the induction coil (22, 22') is at least partially disposed within the housing (21) and / or enclosed within the housing (21); the induction coil (22) preferably includes outer portions (27, 28) projecting away from the housing (21) and / or at least partially defining the outer surface of the sealing unit (18); the outer portions (27, 28) are defined by at least a portion of the corrosion-resistant layer (26) and are configured to be exposed to an external corrosive environment; The sealing unit (18) comprises a power supply group connected to a first end (31) and a second end (32) of the induction coil (22) and configured to apply an alternating current to the induction coil (22). The seal unit according to claim 10.

12. A package forming device (7) for a packaging machine (1), configured to seal at least laterally a tube (4) formed from a multi-layer packaging material to obtain a package (2), The package forming device (7) is configured to transversely seal the tube (4), and comprises an induction sealing device (19), and comprises a sealing unit (18) according to claim 10 or 11. Package forming device (7).

13. A packaging machine (1) for forming packages (2) of pourable product from an advancing tube (4) formed from a web (3) of multi-layer packaging material, comprising: The packaging machine (1) a conveying device (8) configured to advance the web (3) of multi-layer packaging material along a web advancement path (P) and to advance the tube along a tube advancement path (Q); a tube forming and sealing device (9) configured to form a tube (4) from the web (3) of multi-layer packaging material and to longitudinally seal the tube (4); a filling device (10) for filling the tube (4) with a pourable product; A package forming device (7) according to claim 12; A packaging machine (1).

14. A method for manufacturing a multi-layer rod (24) for a sealing unit (18) according to any one of claims 1 to 9, said method comprising: Providing metal plates and nickel alloy plates; brazing the metal plate and the nickel alloy plate together to obtain a multi-layer plate; cutting the multilayer board to obtain at least one multilayer rod (24); A method comprising:

15. 10. A method for manufacturing an induction sealing device (19) comprising at least one induction coil (22, 22') comprising a multilayer rod (24) according to any one of claims 1 to 9 and / or formed from the multilayer rod (24), said method comprising: placing the induction coil (22, 22') in a mold; injecting the molten polymer into a mold so that the metal layer (25) of the induction coil (22, 22') is completely immersed in the molten polymer and at least a remaining portion of the corrosion-resistant layer (26) is not immersed in the molten polymer; A method comprising:

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