Sterilization device with radiation beam emitting device and packaging machine with sterilization device

Abstract

A sterilization apparatus (7) for sterilizing packaging materials (3) comprises one or more radiation beam emitters (20), each configured to emit a radiation beam. Each radiation beam emitter (20) comprises a main housing (21) having an interior space (22) and an exit window (23), and a radiation source (24) arranged within the interior space (22) and configured to generate a radiation beam and cause the radiation beam to exit the interior space (22) through the exit window (23). The exit window (23) comprises a window (25) having carbon.

Description

[Technical field]

[0001] The present invention relates to a sterilization device for sterilizing packaging materials, in particular packaging materials having a multi-layer structure, comprising a radiation beam emitting device.

[0002] Furthermore, the invention relates to a packaging machine for forming pourable packages of food products from a packaging material, in particular a packaging material having a multi-layer structure, comprising a sterilization device having a radiation beam emission device. [Background technology]

[0003] As is well known, many liquid or pourable food products, such as fruit juice, UHT (ultra-high temperature processed) milk, wine, tomato sauce, etc., are sold in packages made from sterile packaging material.

[0004] A typical example is the parallelepiped package for pourable foods known as Tetra Brik Aseptic®, which is made by sealing and folding a laminated packaging material. This packaging material has a base layer, e.g. paper or paperboard, covered on both sides with a layer of heat-sealable plastic material, e.g. polyethylene. In the case of aseptic packaging for shelf-stable products such as UHT milk, the packaging material comprises a layer of oxygen barrier material, e.g. aluminium foil, overlapped with a layer of heat-sealable plastic material, which is covered with another layer of heat-sealable plastic material to form the inner surface of the package that ultimately comes into contact with the food.

[0005] This type of package is typically produced on fully automatic packaging equipment which advances a web of packaging material, sterilizes it, then forms it into a tube, fills it with the aseptically pourable / sterilized product, and then forms it into individual sealed packages.

[0006] It is further known that the automated packaging machine may comprise an isolation chamber in which a web of packaging material is formed and filled with the pourable product. Since the web of packaging material comes into contact with the pourable product, it is necessary to ensure the cleanliness and / or sterility of the isolation chamber and the web of packaging material.

[0007] A typical automated packaging machine therefore comprises a respective sterilisation device arranged upstream of each isolation chamber for sterilising the packaging material.

[0008] Some known sterilization devices include two radiation beam emitters for sterilizing both sides of a web of packaging material by electron beams.

[0009] Each irradiation beam emitting device includes a main housing having an interior space and an exit window, and an irradiation transmission source disposed within the interior space and configured to generate an electron beam and direct the electron beam out of the interior space through the exit window.

[0010] A typical exit window is made from titanium. During use, the exit window absorbs some of the energy of the emitted electrons, resulting in heating of the exit window. This means that the overall energy of the electron beam needs to be kept below a maximum energy value to avoid the exit window rising to undesirable temperature values ​​during use, which would have an undesirable effect on the lifetime of the entire device.

[0011] Thus, while known radiation beam emitters have demonstrated excellent operating results, there is a need in the art to further improve known radiation beam emitters, in particular to further increase the maximum energy value. Summary of the Invention [Problem to be solved by the invention]

[0012] It is a further object of the present invention to provide an improved sterilization apparatus for sterilizing packaging materials, particularly packaging materials having a multi-layer structure, which is simple and low cost.

[0013] Another object of the present invention is to provide an improved simple and low cost packaging machine for forming pourable food packages from a web of packaging material, especially a web of packaging material having a multi-layer construction.

[0014] According to the present invention there is provided a sterilisation device as claimed in claim 1.

[0015] Preferred, non-limiting embodiments of the sterilization device are set forth in the respective dependent claims.

[0016] According to a further aspect of the present invention there is provided a packaging machine as claimed in claim 11. [Means for solving the problem]

[0017] Preferred, non-limiting embodiments of the packaging machine are set forth in the claims dependent on claim 11. [Brief description of the drawings]

[0018] Non-limiting embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0019] [Figure 1] 1 is a schematic diagram, with parts removed for clarity, of a packaging machine equipped with one or more radiation beam emitting devices according to the invention; [Diagram 2] FIG. 2 is an enlarged perspective view, with parts removed for clarity, showing details of the packaging machine of FIG. 1; [Diagram 3] 1 is a schematic diagram of a radiation beam emitting device with parts removed for clarity; [Figure 4] FIG. 4 is a perspective view and partial cross-sectional view of a detail of the radiation beam emitter of FIG. 3, with parts removed for clarity; [Diagram 5] FIG. 2 shows the results of a simulation investigating the dependence of detailed parameters of the radiation beam emitter of FIG. 1 on the surface dose. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Number 1 indicates as a whole a packaging machine for producing (sealed) packages 2 of pourable products, in particular pourable food products such as pasteurised milk, fruit juices, wine, tomato sauces, emulsions, pulp drinks, etc.

[0021] In particular, the packaging machine 1 may produce packages 2 from a packaging material 3, in particular a flat packaging material 3, more in particular a packaging material 3 provided in the form of a web.

[0022] More specifically, the packaging material 3 may have a multi-layer structure.

[0023] More specifically, the packaging material 3 may comprise at least one layer of a fibrous material, such as, for example, a paper or cardboard layer, and at least two layers of a heat-sealable plastic material, such as, for example, polyethylene. One of these two layers of heat-sealable plastic material may define the inner surface of the package 2 that will ultimately be in contact with the pourable product.

[0024] Furthermore, the packaging material 3 may comprise a layer of a gas and light barrier material, such as for example an aluminium foil or an ethylene vinyl alcohol (EVOH) film, in particular arranged between one of the layers of heat-sealable plastic material and the layer of textile material.

[0025] Furthermore, the packaging material 3 may comprise a further layer of heat-sealable plastic material interposed between the layer of gas and light barrier material and the layer of textile material.

[0026] The packaging material 3 may have a first side 4 and a second side 5, in particular the first side 4 being the side of the packaging material 3 that defines the inner surface of the formed package 2 that will ultimately come into contact with the filled pourable food product.

[0027] Preferably, the packaging material 3 may comprise a plurality of repeating units, in particular repeating units arranged successively (and evenly spaced) with respect to one another along the packaging material 3. In particular, each repeating unit may form the basis of one package 2. In other words, the packaging machine 1 may be configured to produce packages 2 from the packaging material 3 such that each package 2 results from one repeating unit.

[0028] In particular, each repeat unit is defined by one respective pattern present on the packaging material 3. More specifically, the pattern is substantially identical for all repeat units, with minor differences from other repeat units, such as an information tag present on the packaging material 3 indicating production date, production lot, personal information, etc.

[0029] Referring to FIG. 1, a packaging machine 1 includes: - a conveying device 6 configured to advance the packaging material 3 along an advance path P; - sterilization equipment 7 for sterilizing packaging materials 3; - an isolation chamber 8 with an internal environment 9, in particular the isolation chamber 8 being arranged downstream of the sterilization device 7 along the forward path P; - a tube forming and sealing device 10 configured in use to form a tube 11 from an advancing packaging material 3 and to longitudinally seal the tube 11 within an internal environment 9; - a filling device 12 configured to fill the tube 11 with a pourable product; - a package forming device 13 configured to at least form and transversely seal the tube 11 and preferably cut the tube 11 transversely to form the (sealed) package 2; Equipped with.

[0030] Advantageously, the conveying device 6 may be configured to advance the tube 11 along a tube advancement path Q towards and at least partially through the package forming device 13 .

[0031] More specifically, the conveying device 6 may be configured to advance the tube 11 and an intermediate part of the tube 11 along the tube advancement path Q. In particular, the intermediate part of the tube 11 means any configuration of the packaging material 3 before obtaining a tube structure and after folding of the packaging material 3 has started. In other words, the intermediate part of the tube 11 is the result of a gradual folding of the packaging material 3 to obtain the tube 11, in particular by overlapping opposite side edges of the packaging material 3 with each other.

[0032] The isolation chamber 8 is configured to protect the internal environment 9 from the (hostile) external environment.

[0033] More specifically, the isolation chamber 8 may be configured such that a tube 11 can be formed, longitudinally sealed, and filled within the sterile internal environment 9 .

[0034] Preferably, the packaging machine 1 may also comprise a conditioning unit configured to define and control the atmospheric and physical and / or chemical conditions within the internal environment 9. In particular, the conditioning unit may be configured to maintain and control the sterility of the internal environment 9. Furthermore, the conditioning unit may be configured to control the temperature and / or humidity and / or pressure.

[0035] Preferably, before operation of the packaging machine 1, the internal environment 9 is subjected to a sterilization process, in particular a chemical and / or physical sterilization process, in order to establish sterility of the internal environment 9. In particular, sterilization in place (SIP) may be performed.

[0036] In particular, the sterilisation device 7 is configured to sterilise the packaging material 3 , in particular the first side 4 and the second side 5 .

[0037] The sterilisation device 7 may also be arranged such that the packaging material 3 is transferred directly from the sterilisation device 7 to the interior space 9 .

[0038] With particular reference to Figures 1 to 4, the sterilisation apparatus 7 comprises one or more radiation beam emitting devices 20 (specifically two are shown), each radiation beam emitting device 20 configured to emit a radiation beam, in particular an electron beam, preferentially at the advancing packaging material 3 during use.

[0039] In particular, each radiation beam makes it possible to sterilize the surface on which it strikes.

[0040] More specifically, the sterilization apparatus 7 comprises at least two irradiation beam emitting devices 20, in particular arranged such that one irradiation beam emitting device 20 directs an irradiation beam, in particular an electron beam, towards the first surface 4 when in use and the other irradiation beam emitting device 20 directs an irradiation beam, in particular an electron beam, towards the second surface 5 when in use.

[0041] Specifically, the two radiation beam emitters 20 may be opposed to each other, and the packaging material 3 may be interposed between the two radiation beam emitters 20 during use.

[0042] With particular reference to FIGS. 2 to 4, each irradiation beam emitter 20 includes: a main housing 21 having an interior space 22 and an exit window 23; a radiation source 24 arranged in the interior space 22 and configured to generate a radiation beam, in particular an electron beam, and to cause the radiation beam, in particular the electron beam, to exit the respective interior space 22 through a respective exit window 23; The present invention may also include:

[0043] More particularly, each exit window 23 comprises and / or defines a window 25 comprising carbon. Even more particularly, each exit window 23 comprises and / or defines a window 25 consisting of carbon.

[0044] Preferably, the window comprises and / or consists of graphite. Preferably, the window comprises and / or consists of graphite foil.

[0045] In particular, each interior space 22 may be under a vacuum.

[0046] Furthermore, each main housing 21 may be provided with an opening and each window 25 may completely cover the opening, in particular such that each particle associated with each radiation beam, in particular each electron beam, must pass through each window 25 to exit each main housing 21.

[0047] According to a possible non-limiting embodiment, the exit window 23 defines the window 25 (i.e. they are coincident).

[0048] According to some possible non-limiting embodiments, window 25 may comprise and / or be composed of pyrolytic graphite foil and / or artificial graphite foil and / or pyrolytic carbon foil and / or highly oriented pyrolytic graphite sheet and / or comprise graphene foil.

[0049] More specifically, graphite is a crystalline form of carbon whose atoms are arranged in a hexagonal structure.

[0050] More specifically, pyrolytic graphite includes multiple graphene layers, and in particular graphene is an allotrope of carbon.

[0051] Additionally, each atom in each graphene layer may be bonded to its three nearest neighbors, specifically by σ bonds, and each atom may contribute one electron to a conduction band, i.e., a depolarized π bond, that spans the graphene layer.

[0052] More specifically, multiple graphene layers of pyrolytic graphite are stacked together by van der Waals interactions between one or more graphene layers to form graphitic domains.

[0053] More specifically, pyrolytic graphite or synthetic graphite is a graphitic material with a highly preferential crystal orientation with respect to an axis perpendicular to the surface of the substrate (according to this embodiment and some possible embodiments of window 25). Pyrolytic graphite may be obtained by graphitization heat treatment or chemical vapor deposition of carbon-containing materials, preferably at temperatures above 2500K.

[0054] Furthermore, hot working of pyrolytic graphite by annealing under compressive stress, preferably at about 3300K, produces highly oriented pyrolytic graphite (HOPG). HOPG is a highly ordered form of high purity pyrolytic graphite. HOPG is characterized by the highest degree of three-dimensional ordering.

[0055] Applicant has observed that the carbon-containing window 25 exhibits superior temperature behavior. In particular, thanks to the carbon-containing window 25, the exit window 23 heats up to a much lower temperature during use compared to state-of-the-art exit windows that rely on titanium.

[0056] For example, applicants have observed that at a power level of 3 kW, the temperature of the titanium foil in each of the leading edge exit windows reaches approximately 300°C, whereas window 25 only reaches approximately 100°C.

[0057] Preferably, the thickness of each window 25 may be less than 50 μm, preferably less than 30 μm.

[0058] Furthermore, the thickness of each window 25 may be greater than or equal to 5 μm, particularly greater than or equal to 8 μm, and more particularly greater than or equal to 12 μm.

[0059] FIG. 5 shows the results of a simulation (considering an energy of 80 kV), in particular a Monte Carlo simulation, showing how the thickness of the window 25 depends on the surface dose. The results for varying the thickness of the window 25 have been normalized taking into account the results when considering windows known in the state of the art (including titanium). The respective curves showing the behavior when considering windows known in the state of the art are shown in bold black. Also, the dashed curve shows the curve for a window 25 thickness of 25 μm, the black curve shows the curve for a window 25 thickness of 12 μm and the grey curve shows the curve for a window 25 thickness of 18 μm. Good operating results are obtained for thicknesses below 50 μm, with preferred thicknesses below 30 μm. Indeed, the applicant has found that the efficiency peak returns when the thickness is below 12 μm.

[0060] Applicants have also verified the results of the simulations with dosimetry.

[0061] According to certain preferred, non-limiting embodiments, each exit window 23 may include a support structure 27 that supports the respective window 25 .

[0062] Additionally, each support structure 27 may include multiple openings.

[0063] More specifically, each support structure 27 may include a plurality of ribs spaced apart from one another and defining an opening.

[0064] Moreover, applicants have determined that the use of windows 25 reduces, particularly by a factor of ten, the temperature gradient across each support structure 27, particularly across each rib, resulting in lower stresses on the material.

[0065] According to certain preferred, non-limiting embodiments, each support structure 27 may include copper, and in particular may be constructed from copper.

[0066] Further, each main housing 21 may include a housing sheet for a respective exit window 23, in which the respective exit window 23 is disposed.

[0067] Advantageously, each housing may comprise an annular cooling channel 29 for cooling fluid, in particular for cooling the respective outlet window 23. Preferably, a part of the respective outlet window 23, in particular the respective support structure 27, may cover the respective cooling channel.

[0068] Additionally, each main housing 21 may also include a respective fastening assembly for fastening a respective exit window 23 within a respective housing seat.

[0069] According to some non-limiting embodiments, each irradiation source 24 may comprise a cathode 31 and, in particular, an electron-generating filament (not shown) surrounded by the respective cathode 31 .

[0070] Preferably, each exit window 23 may function as an anode.

[0071] More particularly, and referring to FIG. 1 , the tube forming and sealing apparatus 10 may include at least two forming ring assemblies 35 that are disposed within the interior environment 9 and configured to cooperate with one another to gradually fold the packaging material 3 into a tube 11, particularly by overlapping the ends of the packaging material 3 with one another.

[0072] Additionally, the tube forming and sealing device 10 may include a sealing head 36 configured to be disposed within the interior environment 9 and to seal the tube 11 longitudinally.

[0073] Furthermore, the filling device 12 may comprise a filling pipe 37 configured to, in use, direct the pourable product to the tube 11. In particular, the filling pipe 37 may be arranged, in use, at least partially within the tube 11 so as to supply the pourable product to the tube 11, in use.

[0074] Furthermore, the package forming device 13 includes: - a plurality of forming and sealing assemblies, each assembly being configured to at least form (shape) the tube 11, to transversely seal the tube 11 and in particular to transversely cut the tube 11; - a transfer unit for advancing the forming and sealing assembly; The present invention may also include:

[0075] In particular, the package forming apparatus 12 may be configured to control the form and seal assembly and transfer units to transversely seal and cut the tube 11 along equally spaced cross sections.

[0076] In use, the packaging machine 1 produces packages 2 for the pourable food product. In particular, the packaging machine 1 forms a tube 11 from the packaging material 3, seals the tube 11 longitudinally, fills the tube 11 with the pourable food product, shapes, seals and transversely cuts the tube 11 to obtain the packages 2.

[0077] Before forming the tube 11 from the packaging material 3, the packaging material 3 is sterilized by a sterilizer 7.

[0078] During sterilization of the packaging material 3 , a radiation beam, in particular an electron beam, is applied to the first side 4 and to the second side 5 .

[0079] Each radiation beam, in particular each electron beam, is generated by a radiation beam emitter 20. Thereby, a radiation beam is generated by a radiation source 24 and emerges from an exit window 23.

[0080] The advantages of the radiation beam emitter 20 and / or the sterilizer 7 and / or the packaging machine 1 according to the invention should be clear from the above description.

[0081] In particular, the use of the pyrolytic graphite exit window 23 heats up at a lower temperature during use compared to known solutions when operating at the same power, which means that the radiation beam emitter 20 can operate at a higher maximum energy, facilitating the overall sterilization process.

[0082] Furthermore, pyrolytic graphite is a relatively inexpensive material.

[0083] Obviously, changes may be made to the radiation beam emitting device 20 and / or the sterilization device 7 and / or the packaging machine 1 described herein without departing from the scope of protection defined in the appended claims.

[0084] According to one or more embodiments, the exit window 23 comprises a window 25 comprising synthetic graphite. Advantageously, the exit window 25 comprising synthetic graphite exhibits superior temperature behavior. In particular, the exit window 23 heats up at a much lower temperature in use compared to state of the art exit windows that rely on titanium. For example, Applicant has observed that at a power level of 3 kW, the temperature of the respective titanium foil of a state of the art exit window reaches approximately 300-400°C, whereas the window 25 reaches approximately 100°C.

[0085] Advantageously, synthetic graphite allows for a robust window 25 insofar as the window 25 can withstand the mechanical stresses caused by the vacuum created.

[0086] According to one embodiment, the exit window 23 may include a coating covering the window 25, preferably configured to prevent oxidation of the window 25.

[0087] Advantageously, the coating layer may protect the window 25 from mechanical and / or chemical interaction with the environment; in particular, the coating may advantageously prevent oxidation of carbon within the window 25.

[0088] According to an embodiment, the thickness of the window 25 may be 10 μm to 50 μm, preferably 12 μm to 50 μm, more preferably 15 μm to 30 μm. The thickness of the window may be 10 μm to 100 μm, for example in the case of a highly crystallized material such as HOPG.

[0089] Advantageously, this thickness allows electrons to penetrate to the outside of the exit window, while at the same time being thicker than conventional exit windows (eg, 7 μm), thus making the exit window 25 easier to manufacture.

Claims

1. A sterilization apparatus (7) for sterilizing packaging material (3), comprising one or more irradiation beam emitters (20) each configured to emit an irradiation beam, Each of the one or more irradiation beam emitting devices (20) described above is: A main housing (21) having an interior space (22) and an exit window (23), An irradiation source (24) is positioned within the internal space (22), generates an irradiation beam, and causes the irradiation beam to exit the internal space (22) through the exit window (23), Equipped with, The aforementioned exit window (23) is equipped with a carbon-containing window (25). Sterilizer (7).

2. The aforementioned window (25) contains artificial graphite, The sterilization apparatus (7) according to claim 1.

3. The window (25) includes and / or is composed of pyrolytic graphite foil and / or The window (25) includes and / or is made of artificial graphite foil. The sterilization apparatus (7) according to claim 1.

4. The aforementioned exit window (23) is provided with a coating that covers the window (25). The sterilization apparatus (7) according to claim 1.

5. The coating is configured to prevent oxidation of the window (25). The sterilization apparatus (7) according to claim 4.

6. Equipped with two irradiation beam emission devices (20), One irradiation beam emitter (20) is positioned to sterilize the first surface (4) of the packaging material (3) when in use, and the other irradiation beam emitter (20) is positioned to sterilize the second surface (5) of the packaging material (3) opposite to the first surface (4) when in use. The sterilization apparatus (7) according to claim 1.

7. Each exit window (23) is further provided with a support structure (27) that supports the window (25). The sterilization apparatus (7) according to claim 1.

8. The thickness of each window (25) is 10 μm to 50 μm. The sterilization apparatus (7) according to claim 1.

9. Each main housing (21) is provided with a housing sheet, and each exit window (23) is located within the housing sheet. The sterilization apparatus (7) according to claim 1.

10. Each housing seat is provided with an annular cooling channel (29) for the cooling fluid, A portion of each outlet window (23) covers the cooling channel (29). The sterilization apparatus (7) according to claim 9.

11. Each irradiation source (24) is configured to generate an electron beam. The sterilization apparatus (7) according to claim 1.

12. The window (25) includes and / or is composed of pyrolysis carbon foil and / or highly oriented pyrolysis graphite sheet, and / or includes graphene foil. The sterilization apparatus (7) according to claim 1.

13. A packaging machine (1) for forming a package (2) filled with a product that can be dispensed from a packaging material (3), The sterilization apparatus (7) according to claim 1, Packaging machine (1).

14. A conveying device (6) that moves the packaging material (3) forward along the forward path (P), An isolation chamber (8) having an internal environment (9), A tube forming and sealing device (10) that forms a tube (11) from the packaging material (3) advancing within the internal environment (9) during use, and seals the tube (11) in the longitudinal direction within the internal environment (9), A filling device (12) for filling the tube (11) with a product that can be dispensed, To form the aforementioned package (2), a package forming apparatus (13) is provided that, when in use, forms the tube (11) which moves forward, seals it laterally, and cuts it laterally. Furthermore, The sterilization device (7) is positioned upstream of the isolation chamber (8) along the forward path (P) of the web. The packaging machine (1) according to claim 13.

15. The irradiation beam emitter (20) irradiates the moving packaging material (3) with sterilization irradiation when in use. The packaging machine (1) according to claim 14.

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