Tube for sealing a packaging material to produce a sealed unit containing a pourable product

Abstract

A sealing unit (6) for sealing a tube (3) of packaging material to produce a package (2) containing a pourable product is described, the sealing unit (6) comprising: a sealing device (11) configured to be arranged in a position close to the tube (3) and to provide the tube (3) with a longitudinal seal (12); and a position adjustment system (13) coupled with the sealing device (11) and configured to adjust the position of the sealing device (11) with respect to the tube (3).

Description

Technical Field

[0001] This invention relates to a tube for sealing packaging materials to produce a sealing unit containing pourable products (preferably pourable food). Background Technology

[0002] As is well known, many pourable foods, such as fruit juice, UHT (ultra-high temperature) milk, wine, and ketchup, are sold in packages made of sterilized packaging materials.

[0003] A typical example is the parallelepiped-shaped packaging used for pourable foods, namely TetraBrik Aseptic (registered trademark), which is made by folding and sealing laminated packaging material rolls.

[0004] The packaging material has a multi-layered structure, including a bottom layer (e.g., made of paper) and two sides covered with heat-sealing plastic material (e.g., polyethylene).

[0005] For aseptic packaging of products intended for long-term storage (such as UHT milk), the packaging material also includes an oxygen barrier layer (such as aluminum foil) stacked on top of a heat-sealed plastic material layer, and then covered with another heat-sealed plastic material layer to form the inner surface of the packaging that ultimately comes into contact with the food.

[0006] This type of packaging is typically produced on fully automated packaging machines that start with multi-layer rolls of packaging material, forming and filling the package.

[0007] Specifically, the packaging material rolls are first wound onto a spool and then fed through multiple unwinding rollers.

[0008] Packaging material rolls are typically placed in a closed, sterile environment and, propelled by the aforementioned unwinding rollers, folded into a continuous tube using a known roll folding device. The tube is then longitudinally sealed, resulting in a continuous longitudinal seal.

[0009] In order to perform the packaging formation operation, in a known but not detailed manner, the tube is continuously fed in a straight vertical direction, filled with sterilized food from above, then formed, sealed, and subsequently cut into equally spaced cross sections extending in a direction orthogonal to the vertical direction.

[0010] This results in a so-called pillow-shaped package, which has a longitudinal sealing strip, a top transverse sealing strip, and a bottom transverse sealing strip. The pillow-shaped package is then cut along its cross-section to separate it from each other and guided to the folding unit of the packaging machine for final folding.

[0011] This allows for the production of finished product packaging.

[0012] To form the tube, the web folding device is configured to fold the web from a sheet-like configuration into a C-shaped configuration and then into a substantially tubular configuration, so that the first longitudinal edge portion of the web overlaps the second longitudinal edge of the web.

[0013] To form the tube with the aforementioned longitudinal seal, the packaging machine comprises a sealing device configured to seal the first longitudinal edge together with the second longitudinal edge.

[0014] Suitably, the sealing device is arranged in a fixed position with respect to the aforementioned straight vertical direction and with respect to the central axis of the tube.

[0015] According to a known configuration, the sealing device comprises a nozzle arranged in proximity to the outer surface of the tube, in particular in proximity to the area in which the first longitudinal edge of the tube overlaps the second longitudinal edge. The nozzle is configured to deliver a hot air flow to this area.

[0016] As is known, the correct formation of the longitudinal seal on the tube is essential for the lasting and secure sealing of the final package.

[0017] Therefore, during the entire production process, the sealing device is preferably arranged in the correct position.

[0018] Although the known packaging machines are structurally and functionally viable, the Applicant has noted that it would be preferable to simplify and improve the installation process of the known packaging machines, as well as to increase their adaptability and flexibility. SUMMARY

[0019] It is therefore an object of the present application to provide a sealing unit for sealing a tube of packaging material, designed to meet at least one of the above in a direct and low-cost manner.

[0020] This object is achieved by the sealing unit described in the appended independent claim 1. Preferred embodiments of the application are set out in the appended dependent claims. BRIEF DESCRIPTION OF DRAWINGS

[0021] Non-limiting embodiments of the application will be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a packaging machine comprising a sealing unit according to the present application, with parts removed for clarity; Figure 2 is a perspective view of the sealing unit in Figure 1 is a perspective view of the sealing unit in Figure 3 is a perspective view of the sealing unit in Figure 2 is an enlarged perspective view of the sealing unit in ​

[0022] With reference to Figure 1 , reference 1 generally indicates a non-limiting example of a packaging machine configured to produce sealed packages 2 containing pourable products, preferably pourable food products, such as pasteurized milk or UHT milk, water, fruit juice, wine, peas, beans, etc.

[0023] In particular, the packaging machine 1 is configured to form, seal and fold the packages 2 starting from a web 4 of packaging material initially wound on a reel 4a and subsequently folded into a tube 3 of packaging material in a manner known per se and not described in detail here.

[0024] Preferably, the packaging material has a multilayer structure (not shown) and comprises a layer of fibrous material, such as paper, covered on both sides with a layer of heat-seal plastic material, such as polyethylene.

[0025] For aseptic packages 2 for long-term storage products, such as UHT milk, the packaging material further comprises a layer of gas- and light-barrier material, such as aluminum foil or ethylene-vinyl alcohol (EVOH) film, superimposed on the layer of heat-seal plastic material and covered by another layer of heat-seal plastic material to form the inner face of the package 2 which is ultimately in direct contact with the pourable product.

[0026] As shown in Figure 1 , the packaging machine 1 comprises a conveying mechanism configured to advance the web 4 along an advancement path.

[0027] The packaging machine 1 comprises a web folding device 5 for progressively folding the web 4 in advancement into a tube 3 of packaging material, in a manner known per se and not described in detail here.

[0028] In particular, in order to form the tube 3, the web folding device 5 is configured to progressively fold the web 4 from a sheet-like structure into a C-shaped structure and then into a substantially tubular structure, so that a first longitudinal edge of the web 4 is partially superimposed on a second longitudinal edge of the web 4.

[0029] The packaging machine 1 comprises a sealing unit 6 for longitudinally sealing the tube 3, which will be described in detail hereinafter.

[0030] Preferably, the packaging machine 1 comprises a sterilization unit (not shown) configured to apply a sterilizing agent, such as a sterilizing agent containing hydrogen peroxide, on the web 4 before it is folded into the tube 3.

[0031] The packaging machine 1 comprises a forming and sealing unit 7 for forming the tube 3 by causing successive longitudinal portions of the tube 3 to assume a predetermined outer shape corresponding to a precursor of the shape of the package 2 and for sealing the tube 3 on equally spaced cross sections (in a manner known per se and not described in detail here).

[0032] The packaging machine 1 comprises an isolating chamber 8 which internally defines an environment containing a controlled atmosphere, in particular a sterilized and / or sterile gas, preferably sterilized and / or sterile air, and houses the forming and sealing unit 7 and the web folding device 5.

[0033] The packaging machine 1 comprises a filling system 10 (only partially shown) configured to fill the pourable product into the tube 3.

[0034] Preferably, the forming and sealing unit 7 has a longitudinal axis X along which, in use, the tube 3 is fed.

[0035] In particular, the longitudinal axis X is parallel to a rectilinear direction, preferably a vertical direction, as shown in Figure 1 .

[0036] Therefore, in use, the tube 3 is fed downwards along the longitudinal axis X and, while being filled from above, is formed and sealed by the forming and sealing unit 7 in a manner known per se and not further detailed here.

[0037] More specifically, the forming and sealing unit 7 stretches the tube 3 along the longitudinal axis X (downwards) in a manner known per se.

[0038] In this way, a plurality of pillow packs 2a is obtained.

[0039] The packaging machine 1 further comprises a folding unit (not shown per se and known) for folding the pillow packs 2a in a manner known per se and not further detailed here, thus obtaining the packages 2.

[0040] The sealing unit 6 comprises a sealing device 11 configured to be arranged (in use) in a position adjacent to the tube 3.

[0041] In particular, the sealing device 11 is arranged in a position along the longitudinal axis X.

[0042] The sealing device 11 is configured to form a longitudinal seal 12 Figure 2 ) on the tube 3.

[0043] In particular, in order to form the longitudinal seal 12 on the tube 3, the sealing device 11 is configured to seal together the first longitudinal edge of the web 4 and the second longitudinal edge of the web 4, as previously described, which are superimposed on each other by the web folding device 5.

[0044] According to the non-limiting embodiment shown, the sealing device 11 comprises a nozzle 11a arranged adjacent to the outer surface 3a of the tube 3, in particular in the proximity of the area in which the first longitudinal edge of the web 4 and the second longitudinal edge of the web 4 overlap. The nozzle 11a is configured to jet a flow of hot gas, preferably hot air, towards this area of the tube 3.

[0045] In use, hot air is sprayed to heat the outer heat-sealing layer of the roll 4 (at both the first and second longitudinal edges), causing the material of the corresponding heat-sealing layer (and / or the longitudinal strips applied to the first or second longitudinal edge) to partially melt and then fuse together.

[0046] This forms a longitudinal seal 12, which extends substantially parallel to the longitudinal axis X.

[0047] More precisely, the longitudinal seal 12 extends substantially parallel to the first direction A, which is parallel to the longitudinal axis X.

[0048] According to another embodiment not shown, the sealing device 11 may include an induction heating device configured to heat the heat-sealing layer by electromagnetic induction using a gas barrier in the presence of the aluminum layer, the specific manner of which is known and will not be described in detail here.

[0049] Therefore, in this case, the sealing device 11 includes an electromagnetic sensor instead of the nozzle 11a.

[0050] According to one aspect of this disclosure, the sealing unit 6 includes a position adjustment system 13 coupled to the sealing device 11 (particularly mechanical and / or dynamic coupling) and configured to adjust the position of the sealing device 11, particularly relative to the tube 3 and / or the fixed frame 14.

[0051] More specifically, the positioning adjustment system 13 is configured to be driven to adjust the position of the sealing device 11 relative to the pipe 3.

[0052] In other words, the sealing unit 6 is configured such that the sealing device 11 can be moved relative to the pipe 3 by driving the position adjustment system 13.

[0053] In fact, the sealing device 11 can be moved relative to the longitudinal axis X by the position adjustment system 13.

[0054] The sealing unit 6 includes a fixing frame 14, which is fixed to the frame of the packaging machine 1 and remains fixed relative to the axis X of the tube 3.

[0055] Typically, the sealing device 11 is coupled to the fixed frame 14 via the position adjustment system 13.

[0056] Specifically, the position adjustment system 13 is configured to adjust the position of the sealing device 11 relative to the fixed frame 14.

[0057] In one embodiment, the position adjustment system 13 is configured to control the rotation of the sealing device 11 relative to at least one of its rotational degrees of freedom.

[0058] Alternatively, the position adjustment system 13 is configured to control the translational movement of the sealing device 11 relative to at least one of its translational degrees of freedom.

[0059] Preferably, the position adjustment system 13 is configured to control both the rotational and translational movements of the sealing device 11.

[0060] In one embodiment, the position adjustment system 13 includes a first rotation adjustment device 15 configured to control a first rotational movement of the sealing device 11 about a first direction A.

[0061] In one embodiment, the position adjustment system 13 includes a second rotation adjustment device 16 configured to control the sealing device 11 to rotate about a second direction B orthogonal to the first direction A.

[0062] In one embodiment, the position adjustment system 13 includes a third rotation adjustment device 17 configured to control the sealing device 11 about a third rotational movement about a third direction C orthogonal to the first direction A and the second direction B.

[0063] It should be noted that each of the first, second, and third rotary adjustment devices can be provided independently or in combination with any other rotary adjustment device therein. In other words, the terms "first," "second," and "third" are used only to distinguish each rotary adjustment device from the other rotary adjustment devices disclosed in this specification and do not imply any mandatory association or order between them.

[0064] Based on the above, the position adjustment system 13 can control the rotation of the sealing device 11 relative to its three rotational degrees of freedom.

[0065] For convenience, each of the first rotation adjustment device 15, the second rotation adjustment device 16 and the third rotation adjustment device 17 includes a rotatably driven screw component for changing the angular position of the sealing device 11 relative to the first direction A, the second direction B or the third direction C, respectively.

[0066] Preferably, each screw component includes a bolt element adapted to accommodate a wrench, thereby enabling the rotational position of the sealing device 11 to be adjusted in a simple manner.

[0067] Conveniently, the first rotary adjustment device 15 and / or the second rotary adjustment device 16 and / or the third rotary adjustment device 17 include corresponding elastic components, in particular springs 50, which are associated with corresponding screw components and configured to bias the screw components in their current positions.

[0068] More specifically, each screw component is held in its current position by a corresponding spring 50.

[0069] By driving the screw component, the corresponding spring 50 is released, thereby changing the angular position of the screw component.

[0070] Once the adjustment is complete, spring 50 will hold the screw component in the new position.

[0071] Advantageously, at least one of the first rotation adjustment device 15, the second rotation adjustment device 16, and the third rotation adjustment device 17, and preferably each of them, includes an indicator member 18 for indicating the current (i.e. actual) angular position of the sealing device 11 relative to its angular reference position, which is related to the corresponding translational degree of freedom or to the tube 3.

[0072] In a preferred embodiment, the indicating element 18 includes a vernier scale (or a nonius scale).

[0073] In this way, the angular displacement and positioning of the sealing device 11 relative to each of the first direction A, the second direction B, and the third direction C can be easily and effectively controlled, that is, relative to each rotational degree of freedom of the sealing device 11.

[0074] Furthermore, the presence of the indicator member 18 significantly reduces the risk of error and allows for fine adjustment of the position of the sealing device 11 relative to its rotational degrees of freedom.

[0075] In one embodiment, the position adjustment system 13 includes a first translation adjustment device 19 configured to control a first translational movement of the sealing device 11 along a first direction A.

[0076] In one embodiment, the position adjustment system 13 includes a second translation adjustment device 20 configured to control a second translational movement of the sealing device 11 along a second direction B.

[0077] In one embodiment, the position adjustment system 13 includes a third translation adjustment device 21 configured to control the third translational movement of the sealing device 11 along a third direction C.

[0078] It should be noted that each of the first, second, and third translation adjustment devices can be provided independently or in combination with any other translation adjustment device. In other words, the terms "first," "second," and "third" are used only to distinguish each translation adjustment device from the other translation adjustment devices disclosed in this specification, and do not imply any mandatory association or order between them.

[0079] Specifically, the first direction A is a direction that is substantially parallel to the X-axis of the tube 3; the third direction C is a direction that extends perpendicular to the first direction A and the outer surface 3a of the tube 3, that is, a direction that extends toward and away from the outer surface 3a; the second direction B is a direction that is perpendicular to the first direction A and the third direction C.

[0080] Based on the above, the position adjustment system 13 can control the translation of the sealing device 11 relative to the three translational degrees of freedom of the sealing device 11, that is, its linear position.

[0081] like Figure 2 As shown, the sealing device 11 includes an air inlet pipe 11b, which is configured to supply air from a known source to the nozzle 11a.

[0082] The air happens to be heated before being guided through pipe 3, for example, by an electric heater.

[0083] In one embodiment, air is heated at a location between the feed pipe 11b and the nozzle 11a.

[0084] Preferably, the first translation adjustment device 19 includes a pair of clamps ( Figure 3 and ​ The clamp is coupled to the feed tube 11b and is configured to be controllable between a "clamped state" and a "released state": in the clamped state, the clamp holds the feed tube 11b in place, thereby defining its fixed position along the first direction A; in the released state, the clamp allows the feed tube 11b to move along the first direction A, thereby achieving position adjustment.

[0085] Preferably, the second translation adjustment device 20 includes an elongated groove extending along the second direction B, and a pin movably engaging with the elongated groove. Specifically, the elongated groove defines a guide rail for the pin. By sliding the pin along the elongated groove, the position of the sealing device 11 in the second direction B can be controlled. The pin can be screwed onto a support plate defining the elongated groove, thereby determining a fixed state of the pin at a selected position on the elongated groove.

[0086] Preferably, the third translation adjustment device 21 includes a lever mechanism, which is only partially shown in the figure. Preferably, the lever mechanism is configured to be driven by an actuator (not shown), such as a pneumatic actuator or an electric motor, and is configured for automatic control.

[0087] In other words, the sealing unit 6 includes an actuator configured to automatically control the third translational movement.

[0088] The lever mechanism is configured such that the sealing device 11 can move (automatically) toward and away from the outer surface 3a of the tube 3 (i.e., along the third direction C) by driving the aforementioned actuator.

[0089] More generally, the third translational movement enables the sealing device 11 (in particular the nozzle 11a) to move toward and away from the outer surface 3a of the tube 3.

[0090] Advantageously, at least one (and preferably each) of the first translation adjustment device 19, the second translation adjustment device 20 and the third translation adjustment device 21 includes an indicator member 18 for indicating the current linear position of the sealing device 11 relative to its linear reference position (which is related to the corresponding translational degree of freedom) or relative to the tube 3.

[0091] In a preferred embodiment, the indicating element 18 includes a vernier scale (or a nonius scale).

[0092] In this way, the translational movement and positioning of the sealing device 11 along the first direction A, the second direction B and the third direction C (i.e., relative to each translational degree of freedom of the sealing device 11) can be easily and effectively controlled.

[0093] Furthermore, the presence of the indicator component 18 significantly reduces the risk of error and allows for fine-tuning of the position of the sealing device 11 with respect to its translational degrees of freedom.

[0094] In view of the above, the position adjustment system 13 includes at least one adjustment device 15, 16, 17, 19, 20, 21, which is configured to control the rotation or translation of the sealing device 11 relative to the tube 3.

[0095] The at least one adjusting device 15, 16, 17, 19, 20, 21 includes an indicating member 18.

[0096] According to another aspect of this disclosure, the sealing unit 6 is configured to be detachably installed in the packaging machine 1, for example, only when the position of the sealing device 11 needs to be adjusted, thereby defining a (preferably detachable) kit for adjusting the position of the sealing device 11, which is configured to form a longitudinal seal 12 on the tube 3 of the packaging material.

[0097] In other words, the sealing unit 6 defines a kit for adjusting the position of the sealing device 11, which is configured to provide a longitudinal seal 12 on the tube 3 of packaging material; the kit is suitable for installation in a packaging machine 1, which is configured to produce sealed packages 2 containing pourable products, starting from a roll of packaging material 4. The packaging machine 1 includes a conveyor configured to advance the roll 4, a roll folding device 5 configured to fold the roll 4 into a tube 3, and the sealing device 11. The kit is detachably coupled to the packaging machine 1 and includes a position adjustment system 13 coupled to the sealing device 11, which is configured to adjust the position of the sealing device 11 relative to the tube 3.

[0098] The advantages of the sealing unit 6 according to the invention will become apparent from the above description.

[0099] In particular, thanks to the presence of the position adjustment system 13, the sealing device 11 can be easily and effectively maintained at its nominal target position relative to the tube 3 throughout the production process.

[0100] Furthermore, the installation process of the sealing device 11 has been significantly improved, as its positioning relative to the pipe 3 is now simpler and highly repeatable. In this regard, the position adjustment system 13 allows for fine-tuning of the position of the sealing device 11.

[0101] In addition, the adaptability and flexibility of packaging machine 1 have been improved, as changes to the specifications of packaging 2 can be completed more quickly.

[0102] In addition, the downtime of the packaging machine 1 is also significantly reduced because the position adjustment system 13 can quickly reposition the sealing device 11 to its expected nominal position or a new nominal position (depending on the actual operating conditions and the actual position of the tube 3 in use).

[0103] Obviously, modifications as described herein can be made to the sealing unit 6 and the packaging machine 1 without departing from the scope of protection defined by the appended claims.

Claims

1. A sealing unit (6) for sealing a tube of packaging material (3) to produce a package (2) containing a pourable product, said sealing unit (6) comprising: - A sealing device (11) configured to be arranged adjacent to the tube (3) and to give the tube (3) a longitudinal seal (12) extending parallel to the first direction (A); and - A position adjustment system (13) coupled to the sealing device (11) and configured to adjust the position of the sealing device (11) relative to the tube (3).

2. The sealing unit as claimed in claim 1, wherein, The position adjustment system (13) is configured to control the rotation of the sealing device (11) relative to at least one of its rotational degrees of freedom.

3. The sealing unit as described in claim 1 or 2, wherein, The position adjustment system (13) is configured to control the translation of the sealing device (11) relative to at least one of its translational degrees of freedom.

4. The sealing unit as described in claim 2 or 3, wherein, The position adjustment system (13) includes at least one adjustment device (15, 16, 17, 19, 20, 21) configured to control the rotation or translation of the sealing device (11) relative to the tube (3); The at least one adjusting device (15, 16, 17, 19, 20, 21) includes an indicating member (18) for indicating the current position of the sealing device (11) relative to its reference position or relative to the tube (3).

5. The sealing unit as claimed in claim 4, wherein, The indicating component (18) includes a vernier scale.

6. The sealing unit as described in any one of claims 3 to 5, wherein, The position adjustment system (13) includes a first rotation adjustment device (15) configured to control a first rotational movement of the sealing device (11) about the first direction (A).

7. The sealing unit as claimed in claim 6, wherein, The position adjustment system (13) includes a second rotation adjustment device (16) configured to control the sealing device (11) to rotate about a second direction (B) orthogonal to the first direction (A).

8. The sealing unit as claimed in claim 7, wherein, The position adjustment system (13) includes a third rotation adjustment device (17) configured to control the sealing device (11) to rotate about a third direction (C), which is orthogonal to both the first direction (A) and the second direction (B).

9. The sealing unit as described in any one of claims 3 to 8, wherein, The position adjustment system (13) includes a first translation adjustment device (19) configured to control the sealing device (11) to make a first translational movement along the first direction (A).

10. The sealing unit as claimed in claim 9, wherein, The position adjustment system (13) includes a second translation adjustment device (20) configured to control the sealing device (11) to make a second translational movement along a second direction (B) orthogonal to the first direction (A).

11. The sealing unit as claimed in claim 10, wherein, The position adjustment system (13) includes a third translation adjustment device (21) configured to control the sealing device (11) to make a third translational movement along a third direction (C), which is orthogonal to the first direction (A) and the second direction (B), and the third translational movement enables the sealing device (11) to move toward or away from the outer surface (3a) of the tube (3).

12. The sealing unit of claim 11, wherein the sealing unit (6) includes an actuator configured to automatically control the third translational movement.

13. The sealing unit as claimed in any of the preceding claims, and comprising a fixing frame (14); in, The sealing device (11) is coupled to the fixed frame (14) via the position adjustment system (13), which is configured to adjust the position of the sealing device (11) relative to the fixed frame (14).

14. A packaging machine (1) for producing sealed packages (2) containing pourable products from a roll of packaging material (4), the packaging machine (1) comprising: - A conveying device for propelling the packaging material roll (4); - A roll folding device (59) for folding the roll (4) into a tube (3); -The sealing unit (6) as described in any of the preceding claims.

15. A kit for adjusting the position of a sealing device (11) configured to provide a longitudinal seal (12) to a packaging material tube (3), the kit being adapted for installation in a packaging machine (1) configured to produce sealed packages (2) containing pourable products from a packaging material roll (4), the packaging machine (1) including a conveyor configured to advance the roll (4), a roll folding device (5) configured to fold the roll (4) into the tube (3), and the sealing device (11), the kit being detachably coupled to the packaging machine (1) and including a position adjustment system (13) coupled to the sealing device (11), the system being configured to adjust the position of the sealing device (11) relative to the tube (3).

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