Anvil, transverse sealing system, filling machine and method for producing packages

Abstract

An anvil (400, 500) for forming a transverse seal (700) of a sleeve-like portion (104) of a packaging material (102) containing a liquid product, the anvil (400, 500) comprising a main surface (402, 502) facing in operation a tube (104), and a ridge (404, 504) provided on the main surface (402, 502), the ridge (404, 504) comprising a first section (406, 506) and a second section (208a, 208b, 508), wherein the first section (406, 506) of the ridge (404, 504) is placed below the second section (408a, 408b, 508) such that, in operation, a stress in the packaging material (102) formed by a hydrostatic pressure of the liquid product is transferred from a first portion (702) of the sleeve-like portion (104) placed above the first section (406, 506) of the ridge to a second portion (704a, 704b) placed above the second section (408a, 408b, 508).

Description

TECHNICAL FIELD

[0001] The present invention relates to packaging technology. More particularly, the present invention relates to a die, a transversal sealing system, a roll-fed filling machine, a blank-fed filling machine and a method for producing packages. BACKGROUND

[0002] Today, roll-fed carton filling machines, such as the Tetra Brik TM Aseptic package machine sold by Tetra Pak® are used for packaging liquid food products, such as milk. So-called blank-fed filling machines are also known. Instead of continuously supplying liquid food product into a tube that is formed into a package, a blank-fed filling machine is fed with so-called blanks, i.e. sleeve-like pieces of packaging material. During the production process, the blanks are closed at one end, filled with product and then closed at the other end. Examples of such machines are the Tetra Rex TM and Tetra Recart TM machines, both sold under the brand Tetra Pak TM .

[0003] In both types of filling machines, longitudinal seals and transversal seals are provided. In a roll-fed filling machine, longitudinal seals are provided so that a tube can be formed, and transversal seals are provided at the lower end of the tube so that a package can be formed from the tube. In a blank-fed machine, the longitudinal seals are usually pre-made, i.e. the blanks provided to the machine are already provided with longitudinal seals. The transversal seals are usually provided when closing the end before filling, i.e. forming a bottom or a top, and when closing the other end. Thus, in a blank-fed machine, there can be two modules that form transversal seals. In contrast, in a roll-fed filling machine, two transversal seals are usually made simultaneously, i.e. a bottom is formed in one package and a top is formed in a subsequent package. By making a cut between the two transversal seals, a package can be continuously provided from the tube.

[0004] However, other alternatives are also possible. For example, in a carton bottle machine, such as the Tetra Top TM machine, the packaging material is roll-fed in the sense that it is provided via a reel. In the machine, the packaging material is cut and provided with longitudinal seals so that blanks are formed. In a first station, a top of plastic is injection moulded onto the blanks, and in a second station, after the product has been filled, a transversal seal is provided so that a bottom of the package is provided.

[0005] When forming a transverse seal, the packaging material is typically heated so that the plastic layer melts and a transverse seal is formed by pressing the two sides of the packaging material towards each other. The heat can be generated by using an inductor to induce a current in an aluminium foil in the packaging material, or by using an ultrasonic horn to provide ultrasonic waves. To provide the pressure, an anvil can be placed opposite the inductor or the ultrasonic horn.

[0006] To enable a reliable transverse seal to be formed, different anvil designs have been developed. According to one anvil design, one or more ridges can be provided on the contact surface of the anvil, i.e. the surface facing the packaging material. By having ridges, the pressure can be applied in a more controlled form, which in turn results in a more reliable transverse seal being formed. Another option is to make the anvil flat and the ultrasonic horn is provided with ridges.

[0007] Although the existing anvils provide a reliable transverse seal, there is still room for improvement. By having a more reliable transverse seal, there will be fewer leaking packages, i.e. fewer quality complaints, and the packages can withstand more rigorous handling, which can be a problem in the distribution process. In addition to reliability, i.e. ensuring that the tube or sleeve is properly closed, an improved anvil can also enable the speed of the filling machine to be increased and less energy is required to provide the transverse seal. SUMMARY

[0008] It is an object of the present invention to at least partly overcome one or more of the above-mentioned limitations of the prior art. In particular, it is an object to provide an anvil which improves the transverse seal in a package.

[0009] According to a first aspect, there is provided an anvil for forming a transverse seal of a sleeve-shaped portion of a packaging material containing a liquid product, the anvil comprising a main surface facing the tube in operation and a ridge provided on the main surface, the ridge comprising a first section and a second section, wherein the first section of the ridge is placed below the second section such that, in operation, a stress in the packaging material formed by a hydrostatic pressure of the liquid product is transferred from a first portion of the sleeve-shaped portion located above the first section of the ridge to a second portion placed above the second section.

[0010] The sleeve-shaped portion can be provided with a longitudinal seal in the first portion of the portion.

[0011] The second section can comprise a first peripheral sub-section and a second peripheral sub-section, and the second section is an intermediate section placed between the first and second peripheral sub-sections.

[0012] The packaging material can be provided with a plastic layer comprising a polymer, wherein the vertical distance between the first section and the second section can be set in dependence of the properties of the polymer and / or the thickness of the plastic layer and / or the stiffness properties of the packaging material.

[0013] A continuous transition from the first section to the second section can be provided, thereby reducing stress in the packaging material.

[0014] The packaging material can be a carton-based packaging material.

[0015] According to a second aspect, there is provided a transversal sealing system comprising a first anvil and a second anvil according to the first aspect, wherein the first anvil is placed above the second anvil in operation, and the second anvil is inverted relative to the first anvil, such that the first section of the ridge of the first anvil is placed below the second section of the ridge of the first anvil, and the first section of the ridge of the second anvil is placed above the second section of the ridge of the second anvil.

[0016] The system can further comprise an ultrasonic horn arranged opposite the first anvil and the second anvil, such that the portion is placed between the ultrasonic horn and the first and second anvils.

[0017] According to a third aspect, there is provided a roll-fed filling machine comprising a transversal sealing system according to the second aspect; a package inverting device placed downstream of the transversal sealing system and configured to turn upside down a package formed by the transversal sealing system; and a folding device configured to fold the package into a final shape.

[0018] According to a fourth aspect, there is provided a blank-fed filling machine comprising a transversal sealing station for closing an end of a portion of packaging material; and a filling station for filling a product into the portion, wherein the transversal sealing station comprises an anvil according to the first aspect.

[0019] According to a fifth aspect, there is provided a method for producing a package, the method comprising providing a sleeve-like portion of packaging material, transversally sealing the portion, wherein the anvil comprises a main surface facing the portion in operation and a ridge provided on the main surface, wherein the ridge comprises a first section and a second section, wherein the first section is placed below the second section in operation, such that stress in the packaging material formed by hydrostatic pressure of a liquid product is transferred from a first part of the portion placed above the first section of the ridge to a second part of the portion placed above the second section.

[0020] The portion can be provided with a longitudinal seal in a first part of the portion.

[0021] The packaging material can be provided with a plastic layer comprising a polymer, wherein the vertical distance between the first section and the second section is set in dependence of a property of the polymer and / or a thickness of the plastic layer and / or a stiffness of the packaging material.

[0022] A continuous transition from the first section to the second section can be provided, thereby reducing stress in the packaging material.

[0023] The packaging material can be a carton based packaging material.

[0024] Further objects, features, aspects and advantages of the present application will appear from the following detailed description, together with the appended drawings. Further, features and advantages described in relation to one of the above aspects should be understood to be applicable to the other aspects, if not explicitly stated otherwise. In the same way, features and advantages described in relation to an example should be understood to be applicable to each of the above aspects, if not explicitly stated otherwise. Yet another aspect of the present application is to have the anvil flat and the ultrasonic horn or inductor provided with a ridge that complies with the described anvil design. This will provide the same effect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Embodiments of the present application will now be described, by way of example only, with reference to the accompanying schematic drawings in which:

[0026] Figure 1 A roll-fed filler is shown.

[0027] Figure 2 A blank-fed filler is generally shown.

[0028] Figure 3 A carton bottle filler is generally shown.

[0029] Figure 4 A front view of an anvil according to a first embodiment is shown.

[0030] Figure 5 A front view of an anvil according to a second embodiment is shown.

[0031] Figure 6 An example of a transversal seal made with a flat ridge anvil is shown.

[0032] Figure 7 An example of a transversal seal made with a Figure 4 flat ridge anvil is shown.

[0033] Figure 8a and Figure 8b A transversal seal system comprising two anvils as shown in Figure 4 is shown.

[0034] Figure 9 is a flow chart showing steps in a method for producing a package. DETAILED DESCRIPTION

[0035] Figure 1A roll-fed carton filling machine 100 is shown by way of example. Packaging material 102 provided on a reel is fed from the reel and forms a tube 104, or more generally a sleeve-like portion. Liquid product is filled into the tube 104 via a valve 106 and a conduit 108. In a transverse sealing system 110, a transverse seal is made and the lower end of the tube 104 is cut off, thereby forming a package 112. After the transverse seal has been made, a package inverting device 114 can be used to invert the packages 112, which can then be folded into their final form by using a folding device 116. This general concept can be implemented in various ways, and Figure 1 The example shown in

[0036] Roll-fed filling machines have many advantages, one of which is that they are fast and cost-effective. However, in the case of relatively small batches, for example 5000 packages to be produced, it can be worthwhile to consider a blank-fed filling machine 200 as generally shown in Figure 2

[0037] Unlike the roll-fed filling machine 100 shown in Figure 1 Blank-fed filling machines are generally divided into different stations and the packages are transported on a conveyor between these stations. For example, as shown in Figure 2 a flat blank 202a, or more generally a sleeve-like portion, can be fed to a first transverse sealing station 204 in which a first end of the blank 202a is closed by a transverse seal. The blank 202b, which at this stage has a closed first end, can then be fed to a filling station 206 in which the blank 202b is filled with product. Next, the blank 202c, which at this stage has a closed first end and is filled with product, can be fed to a second transverse sealing station 208 in which a second end of the blank 202c is closed, so that the blank 202d, which at this stage is filled with product and has closed ends, can be completed. In further stations, which are not shown, placed downstream, the blank 202d can be folded into a package and also provided with, for example, a best before date by using a printer.

[0038] The first transverse sealing station 204 and the second transverse sealing station 206 are generally designed to make one transverse seal at a time, rather than a transverse sealing system as shown in Figure 1 in which two transverse seals are made at the same time, so that the tube 104 can remain closed at the lower end, although a portion is cut off and forms a package.

[0039] Figure 3 A so-called carton bottle machine 300 is shown generally by way of example. As in Figure 2 ​As for the blank-fed filling machine 200 illustrated, the carton bottle filling machine 300 comprises different stations. The blank 302a, which is folded flat at this stage, can be fed to a molding station 304, in which a top made of plastic is molded onto the blank 302, so that a blank 302b is formed, which is closed at one end by the top at this stage. Next, the blank 302b can be filled with a product in a filling station 306. Then, the blank 302c, which is closed at one end by the top and filled with the product at this stage, can be fed to a transverse sealing station 308, in which the other end of the blank 302c is closed by performing a transverse seal, thereby forming a blank 302d, which is closed at both ends and filled with the product. Even if not illustrated, further stations can be provided downstream, for example to fold the blank 302d into a package and to invert the package.

[0040] In other words, in a carton bottle machine, Figure 2 The first transverse sealing station 204 in the blank-fed filling machine 200 illustrated in Figure 2 The blank-fed machine 200 illustrated in Figure 3 The carton bottle machine 300 illustrated in) is replaced by the molding station 304. However, both machines (i.e.

[0041] In Figure 4 In an example, an anvil 400 is illustrated, which can be used to generate a transverse seal in a sleeve-like portion, for example in the tube 104 illustrated in Figure 1 In an example, an anvil 400 is illustrated, which can be used to generate a transverse seal in a sleeve-like portion, for example in the tube 104 illustrated in Figure 2 and 3 In an example, an anvil 400 is illustrated, which can be used to generate a transverse seal in a sleeve-like portion, for example in the tube 104 illustrated in

[0042] As shown in the figure, the first section 406 can be placed below the second sections 408a and 408b. One advantage of this is that, during operation, the stress in the packaging material 102 (more particularly, the packaging material forming the transverse seal) caused by the hydrostatic pressure of the product can be transferred from the first portion placed above the first section 406 to the second portion of the sleeve-shaped portion placed above the second sections 408a and 408b. By using stiffness in the packaging material 102 in this way, the risk of weak points forming at the intersection of the longitudinal and transverse seals can be mitigated or at least reduced.

[0043] To determine the vertical distance VD between the first segment 406 and the second segments 408a, 408b, the characteristics of the packaging material 102 can be considered. For example, if a cardboard-based packaging material is used and this includes a plastic layer (i.e., a polymer-based layer), the characteristics of the polymer can be considered. Additionally, the thickness of the plastic layer can be considered. Furthermore, the stiffness of the packaging material, such as the thickness of the cardboard layer of the packaging material, can be considered.

[0044] As shown in the figure, the transition from the first segment 406 to the second segments 408a and 408b can be continuous, i.e., not gradual. One advantage of doing so is that it reduces the risk of stress formation in the packaging material, which in turn provides a more reliable lateral seal.

[0045] Figure 4 The anvil 400 shown can be found to be used for Figure 1 The roll-feed filling machine 100 shown is because, for roll-feed filling machines, the longitudinal seal is usually placed in the middle of the transverse seal.

[0046] Figure 5 Another anvil 500 is also shown as an example. For example... Figure 4 The anvil 400 shown Figure 5 The anvil 500 shown is provided with a main surface 502 having a ridge 504. Furthermore, the ridge 504 is divided into a first segment 506 and a second segment 508, wherein the first segment 506 is positioned below the second segment 508. Figure 4 The anvil 400 shown differs in that the first section 506 is not positioned in the middle to face the middle portion of the sleeve-shaped part, but rather positioned to face the peripheral sections. This is in sleeve-shaped filling machines (e.g., Figure 2 The sleeve-shaped filling machine 200 shown may be advantageous in which the billets 202a-202d may be provided with longitudinal seals in the peripheral sections.

[0047] exist Figure 6The transverse seal 600 is illustrated by way of example. The transverse seal shown is created using a flat-ridged anvil (i.e., anvil not positioned such that the first section is placed below the second section, but both sections are placed on the same horizontal plane). As indicated by the arrow, the stress in the packaging material 102 is higher in the intersection area 602 where the longitudinal seal and transverse seal coincide. One reason for the higher stress in this area is the presence of three layers of packaging material within this area, compared to two layers outside this area.

[0048] Figure 7 Another transverse seal 700 is shown. This transverse seal 700 has been used... Figure 4 The anvil 400 shown is formed. As indicated by the arrow, in the first portion 702 corresponding to the first section 406, the stress is lower than the stress in the first peripheral sub-part 704a corresponding to the first peripheral sub-section 408a and the second peripheral sub-part 704b corresponding to the second peripheral sub-section 408b. Therefore, in the intersection region 706 where the longitudinal seal and the transverse seal converge, the stress is lower than... Figure 6 The stress in the intersection region 602 of the transverse seal 600 shown. The stress in the corner regions 708a and 708b can also be reduced by having an inclined curvature, i.e., a continuous transition, between the first section 406 and the second sections 408a and 408b.

[0049] Figure 8a and 8b Showing more details Figure 1 The transverse sealing system 110 shown. Figure 8a A cross-sectional side view is shown, and Figure 8b A front view of the anvil is shown.

[0050] As mentioned above, in Figure 1 In the roll-feed filling machine 100 shown, two lateral seals can be performed simultaneously. This is achieved by placing two anvils 802a, 802b at a distance from each other, thus forming a slit 804 between them. This slit 804 allows the cutter 806 to be used to cut the tube 104 after the lateral seal has been performed. On the same side as the cutter 806, an ultrasonic horn 808, or other means for generating heat to melt the plastic layer in the packaging material, can be provided.

[0051] As shown in the figure, the two anvils 802a and 802b can be arranged such that they are placed in opposite directions, that is, the first anvil 802a can be placed together with the first section located below the second section of the spine, while the second anvil 802b can be placed together with the first section above the second section. One advantage of this is that after lateral sealing, the stress caused by hydrostatic pressure will be reduced regardless of how the package is turned over.

[0052] Figure 9 is a flow chart illustrating steps in the method 900. In a first step 902, a sleeve-like portion is provided. This can be achieved by feeding a tube 104 into a transverse sealing system 110 in a reel-fed filler machine 100, or this can be achieved by conveying a blank 202a-d, 302a-d into any of the transverse sealing stations in a carton bottle machine 200 as shown in Figure 2 or a carton bottle machine 300 as shown in Figure 3 In a second step 904, the portion is transversely sealed.

[0053] It should be understood that expressions such as "above" or "below" refer to typical situations of applying the device or method, and thus these expressions should be interpreted broadly unless explicitly stated otherwise. Furthermore, the skilled person understands the orientation, e.g. the orientation of the tube, is to ensure that the product is kept in place and that the principle of sealing does not rely on the orientation in the same way.

[0054] Although it has been described that the anvil comprises a first section and a second section placed at different levels to reduce the tension in the packaging material forming the transverse seal, it is also possible to adapt the ultrasonic horn or inductor such that the heating is provided at different levels corresponding to the first and second sections, such that the same effect can be achieved even if the anvil is flat. Furthermore, it is also possible to use a combination, i.e. a combination of an anvil with a first and second section as described above and an ultrasonic horn or inductor providing heating at different levels.

[0055] From the above description it can be seen that although various embodiments of the application have been described and shown, the application is not limited thereto but can also be embodied in other ways within the scope of the subject matter defined in the appended claims.

Claims

1. An anvil for forming a transversal seal (700) of a sleeve-like portion of a packaging material (102) containing a liquid product, the anvil comprising a main surface facing in operation a tube (104), and a ridge provided on the main surface, the ridge comprising a first section and a second section, wherein the first section of the ridge is placed below the second section such that, in operation, a stress in the packaging material (102) formed by a hydrostatic pressure of the liquid product is transferred from a first portion (702) of the sleeve-like portion placed above the first section of the ridge to a second portion (704a, 704b) placed above the second section, wherein a longitudinal seal is provided in the first portion (702), wherein the second section comprises a first peripheral sub-section (408a) and a second peripheral sub-section (408b) and the first section is an intermediate section placed between the first peripheral sub-section (408a) and the second peripheral sub-section (408b), wherein a continuous transition from the first section to the second section is provided such that the stress in the packaging material (102) is reduced.

2. The anvil according to the preceding claim 1, wherein, the packaging material (102) is provided with a plastic layer comprising a polymer, wherein a vertical distance (VD) between the first section and the second section is set in dependence of a property of the polymer and / or a thickness of the plastic layer and / or a stiffness property of the packaging material (102).

3. The anvil according to the preceding claim 1 or 2, wherein the packaging material is a carton-based packaging material.

4. A transversal sealing system (110) comprising a first anvil (802a) and a second anvil (802b), the first anvil (802a) and the second anvil (802b) according to any one of the preceding claims 1 to 3, wherein the first anvil (802a) is placed in operation above the second anvil (802b) and the second anvil (802b) is inverted relative to the first anvil (802a) such that the first section of the ridge of the first anvil (802a) is placed below the second section of the ridge of the first anvil (802a) and the first section of the ridge of the second anvil (802b) is placed above the second section of the ridge of the second anvil (802b).

5. The transversal sealing system (110) according to claim 4, further comprising an ultrasonic horn (808) provided opposite the first anvil (802a) and second anvil (802b) such that the sleeve-like portion is placed between the ultrasonic horn (808) and the first anvil (802a) and second anvil (802b).

6. A roll-fed filling machine (100) comprising The transversal sealing system (110) according to any one of claims 4 or 5; a package inverting device (114) placed downstream of the transversal sealing system (110) and configured to invert a package (112) formed by the transversal sealing system, and a folding device (116) configured to fold the package into a final shape.

7. A blank-fed filling machine (200) comprising a transversal sealing station for closing an end of a sleeve-like portion of a packaging material, and a filling station for filling a product into the sleeve-like portion, wherein the transversal sealing station comprises an anvil according to any one of claims 1 to 3.

8. A method for producing a package, the method comprising providing a sleeve-like portion of a packaging material (102), transversally sealing the sleeve-like portion, wherein an anvil comprises a main surface facing the sleeve-like portion in operation, and a ridge provided on the main surface, wherein the ridge comprises a first section and a second section, wherein the first section is placed below the second section in operation, such that a stress in the packaging material (102) formed by a hydrostatic pressure of a liquid product is transferred from a first portion (702) of the sleeve-like portion placed above the first section of the ridge to a second portion (704a, 704b) placed above the second section, the first portion (702) being provided with a longitudinal seal, wherein the second section comprises a first peripheral sub-section (408a) and a second peripheral sub-section (408b), and the first section is an intermediate section placed between the first peripheral sub-section (408a) and the second peripheral sub-section (408b), wherein a continuous transition from the first section to the second section is provided, such that the stress in the packaging material (102) is reduced.

9. The method according to claim 8, wherein the packaging material (102) is provided with a plastic layer comprising a polymer, wherein a vertical distance (VD) between the first section and the second section is set in dependence of a property of the polymer and / or a thickness of the plastic layer and / or a stiffness of the packaging material (102).

10. The method according to claim 8 or 9, wherein the packaging material is a carton-based packaging material.

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