Packaging machine and method for producing packages from packaging material

Abstract

A packaging machine and method for producing sealed packages from a packaging material fed along a transport path (P), the packaging machine (1) comprising: a folding unit (4) arranged along said transport path (P) for folding the packaging material from a planar shape into a tube (5) having a longitudinal axis (Y), wherein the first edge (13B) of the packaging material partially overlaps the second edge (13A) of the packaging material; and a control device (8) with an imaging device (9) having at least one sensor (11), in particular a camera (11A), arranged downstream of the folding unit (4) along the transport path (P) and configured to frame at least a longitudinal portion of the tube (5) and to generate a signal; and a control unit (16) connected to the imaging device (9) and configured to measure an angular position of the formed tube (5) relative to the longitudinal axis (Y) based on the signal.

Description

Technical Field

[0001] The present invention relates to a packaging machine and a packaging method for producing packages from packaging material. In particular, the present invention relates to a packaging machine comprising a control device for detecting parameters of a tube formed by folding packaging material and filled with a product to be packaged. In particular, the present invention also relates to a packaging method comprising the step of detecting parameters of a tube formed by folding packaging material and filled with a product to be packaged. Background Art

[0002] It is known that many liquid or pourable food products, such as pasteurized milk or ultra-high temperature (UHT) milk, ketchup, wine, fruit juice are sold in packages made of sterilized packaging material.

[0003] Such packages are usually produced by automatic packaging machines which feed the packaging material web through a sterilization unit by means of known guiding elements, such as rollers, and alternatively sterilize the packaging material web by chemical sterilization in a sterilization bath (e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution) or by physical sterilization (e.g. by means of an electron beam).

[0004] The packaging machine further comprises a folding unit, which is arranged downstream of the sterilization unit and is arranged to fold the packaging material web to produce a continuous tube. Inside the folding unit, the packaging material web is folded from a continuous planar shape into a continuous tubular shape with a vertical axis. The planar packaging material web is folded into a cylinder, which is in turn divided into a plurality of pillow-shaped packages, which are subjected to a continuous mechanical folding operation to obtain a finished sealed package. The folding unit is preferably arranged in a fixed structure, wherein the packaging material web is maintained in a sterile air environment. The folding unit further comprises a plurality of folding devices placed in series (one after another): by interaction with the folding devices, the opposite side edge portions (or edge regions) of the packaging material web are superimposed one on top of the other so as to form a tube and define an overlapping area.

[0005] The packaging machine comprises a sealing unit, which is arranged downstream of the folding unit, for sealing overlapping edge portions of the web of packaging material to obtain a liquid-tight longitudinal seal within the tube.

[0006] The pourable food product is continuously filled into the tube via a pouring conduit which extends partly into the interior of the tube and is part of the filling route.

[0007] The tube is finally sent to the forming and transverse sealing unit where it is clamped, transversely sealed and cut to form pillow packs.

[0008] In the above-mentioned packaging machines, in order to ensure good quality of the transverse sealing of the packaging material tube, the tube has to be fed in such a way that the overlapping area has a predetermined angular position with respect to the vertical axis and that said overlapping area has a predetermined width.

[0009] Therefore, there is a strong need for a reliable measurement of the angular position of the overlap region relative to the vertical axis of the tube. Summary of the invention

[0010] The object of the present invention is to provide a packaging machine for producing packages from packaging material which does not suffer from the above-mentioned disadvantages and which is in particular easy and economical to manufacture.

[0011] Another object of the invention is to provide a packaging method for producing a package from a packaging material which does not suffer from the above-mentioned disadvantages and which is particularly easy and economical to implement.

[0012] According to the present invention, there are provided a packaging machine and a packaging method for producing packages from packaging material according to the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:

[0014] - Figure 1 is a perspective view of a packaging machine for producing packages from packaging material according to the invention, with some parts removed for the sake of clarity;

[0015] - Figure 2 yes Figure 1 A schematic side view of a first part of a packaging machine;

[0016] - Figure 3 yes Figure 1 A perspective view of a second portion of the packaging machine;

[0017] - Figure 4 Shows the use of Figure 1 A first embodiment of a packaging machine for obtaining a planar portion of a packaged packaging material;

[0018] - Figure 5 Shows Figure 4 A partial view of a tube obtained by folding a portion of the packaging material in the tube;

[0019] - Figure 6 Shows the use of Figure 1 A second embodiment of a packaging machine for obtaining a planar portion of a packaged packaging material; and

[0020] - Figure 7 Shows Figure 6 A partial view of a tube is obtained by folding a portion of the packaging material in the tube. DETAILED DESCRIPTION

[0021] Figure 1 and Figure 2 The present invention generally shows a packaging machine 1 for continuously producing sealed packages containing pourable food products, such as pasteurized milk or extended shelf life (UHT) milk, ketchup, wine, fruit juice. The sealed packages are obtained from packaging material unwound from a reel 21 and fed along a conveying path P. When unwound from the reel 21, the packaging material has the shape of a continuous flat packaging material web 20.

[0022] Typically, the packaging material has a multilayer structure. More specifically, the packaging material may include at least one fibrous material layer, such as a paper or cardboard layer, and at least two heat-sealing plastic material layers, such as polyethylene, between which the fibrous material layers are placed. One of the two heat-sealing plastic material layers may define an inner face of the package that eventually contacts the pourable product.

[0023] According to some possible non-limiting embodiments, the packaging material may further comprise a layer of gas barrier and light barrier material, such as an aluminum foil or an ethylene vinyl alcohol (EVOH) film, in particular arranged between one of the heat-sealable plastic material layers and the fiber material layer. Preferably, the packaging material may further comprise another layer of heat-sealable plastic material placed between the gas barrier and light barrier material layer and the fiber material layer.

[0024] The packaging machine 1 comprises a sterilization unit 3 with a sterilization bath 19, in which a chemical sterilant, such as a hydrogen peroxide solution, is applied to a packaging material web 20. The packaging material web 20 is fed through the sterilization unit 3 by known guide elements, such as rollers or the like.

[0025] The packaging machine 1 further comprises a folding unit 4 arranged downstream of the sterilization unit 3 along the conveying path P. The folding unit 4 preferably extends substantially vertically along the conveying path P for producing a continuous tube 5. In particular, inside the folding unit 4, the packaging material web 20 is folded from a continuous planar shape into a continuous tubular shape having a longitudinal axis Y. In particular, the longitudinal axis Y is arranged in the vertical direction.

[0026] The folding unit 4 is defined within a fixed structure 6, wherein the packaging material web 20 is maintained in a sterile air environment. The folding unit 4 also includes a plurality of folding devices 100 placed in series (one after another) along the conveying path P, each of the folding devices 100 including a plurality of folding rollers cooperating to fold the packaging material web 20.

[0027] The packaging machine 1 comprises a sealing unit 7 (of a known type, not described in detail) for sealing the overlapping side edges 13A, 13B of the packaging material so as to obtain a liquid-tight longitudinal seal inside the tube 5 .

[0028] The tube 5 is continuously filled with the pourable food product via a pouring duct 101 which extends partly inside the tube 5 and is part of the filling route.

[0029] The tube 5 is sent to a forming and transverse sealing unit (not shown) where the tube 5 is clamped to transversely seal the tube and form the pillow pack 2. Finally, the pillow pack 2 is subjected to a continuous mechanical folding operation to obtain a finished sealed package.

[0030] The packaging machine 1 comprises a control device 8, which is configured to measure and control the angular position T of the edge 13B relative to the longitudinal axis Y (i.e. the rotation or twisting of the tube 5 around the longitudinal axis Y) and / or the width of the overlapping area AO defined by the overlapping parts of the packaging material edge 13A and the packaging material edge 13B.

[0031] The packaging material web 20 comprises a plurality of reference marking patterns 12 arranged one behind the other along the longitudinal dimension of the packaging material web 20 (and the tube 5) to provide information about the position of the packaging material.

[0032] Each reference marking pattern 12 defines, or is part of, a unit of packaging material 13 for forming a respective sealed package.

[0033] Figure 4 A first embodiment of a reference mark pattern is shown. The reference mark pattern 12 comprises at least two reference marks 14, 15. In the embodiment shown, the reference marks 14, 15 are dedicated marks, having a generally square shape. Alternatively, the reference marks 14, 15 may be already existing marks (e.g. a splicing mark or a barcode or the like).

[0034] The reference mark 14 is arranged near the edge 13A of the packaging material. The reference mark 14 has a reference area 14A, for example an edge area facing the edge 13A.

[0035] A distance D is defined between the edge 13A of the packaging material and the reference area 14A. 1 The distance D 1 Not zero.

[0036] The reference mark 15 is arranged in the vicinity of the packaging material edge 13B. In particular, the reference mark 15 has a reference area 15B, preferably corresponding to the packaging material edge 13B.

[0037] The second edge 13A may include a portion of the packaging material between a boundary of the second edge 13A and the reference mark 14 .

[0038] The first edge 13B of the packaging material may be placed at least partially on top of the second edge 13A, ie the (outer) border of the edge 13B of the packaging material may be placed on top of the second edge 13A.

[0039] The control device 8 comprises a sensor device 17 having at least one sensor 18. According to a first embodiment, the sensor 18 frames a longitudinal portion of a packaging material web 20. Preferably, the longitudinal portion of the packaging material web 20 framed by the sensor 18 comprises a packaging material unit 13. Even more preferably, the longitudinal portion of the packaging material web 20 framed by the sensor 18 corresponds to the packaging material unit 13. In one embodiment, the sensor 18 is preferably a camera 18A.

[0040] The sensing device 17 is configured to measure the distance D of each packaging material unit 13 when the packaging material has a planar shape. 1 The sensor device 17 is arranged along the conveying path P. Preferably, the sensor device 17 is arranged upstream of the sterilization unit 3 .

[0041] The control device 8 also includes Figure 3 The control device 8 preferably further comprises a fixed frame having a movable bracket (not shown) supporting the imaging device 9. The movable bracket can rotate about an axis between a working position and a rest position, in which the imaging device 9 faces the tube 5 and is arranged near the tube 5, and in which the imaging device 9 does not face the tube 5 and is arranged at a distance from the tube 5.

[0042] The imaging device 9 comprises at least one sensor 11, which is adapted to frame at least a longitudinal portion of the tube 5. The sensor 11 is preferably a camera 11A. The imaging device 9 is arranged downstream of the sealing unit 7. In particular, the sensor 11, i.e. the camera 11A, is adapted to frame a longitudinal portion of the tube 5. Preferably, the longitudinal portion of the tube 5 framed by the sensor 11 comprises a packaging material unit 13. Even more preferably, the longitudinal portion of the packaging material web 20 framed by the sensor 18 corresponds to the packaging material unit 13.

[0043] When the packaging material web 20 is folded from a flat shape into a (e.g., substantially) tubular shape, the packaging material edge 13B at least partially overlaps the packaging material edge 13A, thereby defining an overlapping area AO formed by the overlapping side portions of the packaging material. During the preliminary setting and design phase of the working cycle of the packaging machine 1, a reference value for the width of the overlapping area AO is defined. In other words, the reference value is a preferred value or an optimal value corresponding to the correct working state of the packaging machine 1. It is worth noting that the distance D must be selected 1(When printing the mark 14 on the packaging material), it is larger than the reference value. In addition, a distance D is defined between the reference area 15B (which corresponds to the edge 13B of the packaging material in the embodiment shown) and the reference area 14A. 2 When the packaging material web 20 has a (eg substantially) tubular shape, the distance D is measured. 2 ,like Figure 5 As shown. Distance D 2 The measurement is carried out by the imaging device 9 in particular for each packaging material unit 13 .

[0044] Finally, the control device 8 comprises a control unit 16 connected both to the imaging device 9 and to the sensing device 17. In particular, the imaging device 9 is designed to generate a signal indicating the distance D of each unit 13 of packaging material. 2 The sensor device 17 is designed to generate a signal indicating the distance D of each packaging material unit 13. 1 The control unit 16 transmits the signal to the control unit 16. The control unit 16 passes the distance D of each packaging material unit 13. 1 With distance D 2 The actual value of the overlap area AO is calculated from the difference between them.

[0045] The control unit 16 also compares the actual value of the overlap area AO with a reference value. In case the difference between the actual value and the reference value of the overlap area AO exceeds a predetermined threshold, the control unit 16 is designed to generate a warning signal for informing of an undesirable significant deviation from the reference value.

[0046] According to a preferred embodiment, the control unit 16 is realized to control the folding unit 4 and the sealing unit 7 based on the actual value of the overlap area AO.

[0047] According to another embodiment not shown, the reference mark pattern 12 comprises the reference mark 14 as described above, and the reference mark 15 is at the packaging material edge 13B. In other words, the reference mark pattern 12 does not comprise a dedicated reference mark 15, but the reference mark 15 is defined by the packaging material edge 13B. The distance D measured by the imaging device 9 2 Defined between packaging material edge 13B and reference area 14A.

[0048] Figure 6 and Figure 7 A second embodiment of a reference mark pattern 12 is shown.

[0049] The reference mark pattern 12 comprises at least two reference marks 14*, 15*. In the embodiment shown, the reference marks 14*, 15* are already existing marks (such as splicing marks or bar codes or the like). Alternatively, the reference marks 14*, 15* can be dedicated marks.

[0050] The reference mark 14* is arranged near the packaging material edge 13A and the reference mark 15* is arranged near the packaging material edge 13B.

[0051] The first edge 13B may comprise a portion of the packaging material between a border of the first edge 13B and the reference mark 15*. The second edge 13A may comprise a portion of the packaging material between a border of the second edge 13A and the reference mark 14*.

[0052] For example, the (outer) border of edge 13B of the packaging material may be placed on top of the second edge 13A.

[0053] according to Figure 6 and Figure 7 In the embodiment shown in FIG. 1 , the sensor 18 is a camera 18A or alternatively is an through-beam sensor 18 , preferably an through-beam laser sensor 18 .

[0054] The sensing device 17 is configured to measure a width V of each packaging material unit 13, ie a width from a packaging material edge 13A to a packaging material edge 13B of the packaging material web 20, when the packaging material has a planar shape.

[0055] Furthermore, the manufacturer of the packaging material web 20 provides information about the packaging material, such as the distance D between the reference markings 14*, 15*. 3 In more detail, the manufacturer of the packaging material web 20 provides a distance D defined between a reference point 14A* of the reference marking 14* and a reference point 15A* of the reference marking 15* (in particular an edge). 3 Therefore, the distance D 3 has a predefined value stored in the control unit 16 .

[0056] The imaging device 9 is configured to measure the distance D between the reference mark 14* and the reference mark 15*. 4 , for example when the packaging material is folded into a (eg substantially) tubular shape. In more detail, the distance D 4 Defined between a reference point 15A* of the reference marking 15* and a reference point 14A* of the reference marking 14* of the tube 5 .

[0057] The imaging device 9 is designed to generate an image indicating the distance D of each packaging material unit 13. 4 The control unit 16 then calculates the distance D3 Add the distance D 4 To calculate the total perimeter of each packaging material unit 13. Finally, the control unit 16 calculates the actual value of the overlapping area AO by the difference between the width V and the total perimeter of each packaging material unit 13 obtained as described above.

[0058] In this case, too, if the difference between the actual value of the overlap area AO and the reference value exceeds a predetermined threshold, the control unit 16 is designed to generate a warning signal for informing that there is an undesirable significant deviation from the reference value. According to a preferred embodiment, the control unit 16 is implemented to use the actual value of the overlap area AO for closed-loop control of the folding unit 4 and / or the sealing unit 7.

[0059] The image of each packaging material unit 13 provided by the imaging device 9 is used to measure the angular position T of the formed packaging material edge 13B relative to the longitudinal axis Y, which is representative of the rotation or twisting of the tube 5 about the longitudinal axis Y.

[0060] According to a first embodiment, the camera 11A is suitable for continuously acquiring images of at least a longitudinal portion of the tube 5 and of a reference mark (not shown). In particular, the camera 11A is suitable for framing the longitudinal portion of the tube 5 and the reference mark. The reference mark is connected to the frame of the packaging machine 1 and is therefore arranged in a fixed position relative to the tube 5 advancing along the advancement path P. According to a possible embodiment, the reference mark is defined by a slit in a bracket connected to the frame of the packaging machine 1.

[0061] For each image acquired by the camera 11A, the control unit 16 is configured to measure, based on the position of the packaging material edge 13B relative to the reference mark, an angular position T of the packaging material edge 13B relative to the longitudinal axis Y. In particular, the control unit 16 is configured to measure the angular position T of the packaging material edge 13B relative to the longitudinal axis Y based on the distance of the packaging material edge 13B from the reference mark.

[0062] In one or more embodiments, the control unit 16 is configured to measure the angular position T of the wrapper edge 13B relative to the longitudinal axis Y based on the position of the (outer) boundary of said wrapper edge 13B relative to the reference mark.

[0063] According to a further preferred embodiment, the camera 11A is adapted to acquire a reference image during a preliminary setup phase. The reference image comprises at least a longitudinal portion of the tube 5 and a removable reference marker. The reference marker is connected to the frame of the packaging machine 1. According to a possible embodiment, the reference marker is defined by a slit in a bracket that is detachably connected to the frame of the packaging machine 1. After acquiring the reference image during the preliminary setup phase, the removable reference marker is removed from the packaging machine 1 and the reference image is stored in the control unit 16.

[0064] The control unit 16 is configured to compare the image provided by the imaging device 9 with a reference image. In particular, the control unit 16 is configured to measure the angular position T of the packaging material edge 13B relative to the longitudinal axis Y based on a displacement of the packaging material edge 13B relative to a reference position of the packaging material edge 13B in the reference image.

[0065] In both embodiments, the assessment of the correct positioning of the packaging material edge 13B allows the user to determine whether the formed tube 5 is arranged in the correct position relative to the longitudinal axis Y. According to a preferred embodiment, the control unit 16 is indeed implemented to control the folding unit 4 and the sealing unit 7 based on the angular position T of the packaging material edge 13B.

[0066] In case the angular position T of the formed packaging material edge 13B relative to the longitudinal axis Y is greater than a predetermined threshold value, the control unit 16 is designed to generate a warning signal for informing of an undesired significant deviation.

[0067] According to a preferred embodiment, the control unit 16 is configured to use the angular position T of the packaging material edge 13B for closed-loop control of the folding unit 4 and / or the sealing unit 7 .

[0068] Obviously, using the same image provided by the camera 11A for each unit 13 of packaging material, the control device 8 can measure and control both the actual value of the overlap area AO and the twisting of the tube 5 about the longitudinal axis Y.

[0069] Reference numerals list 1 Packaging Machine 2 Packs 3 Sterilization Unit 4 Folding units 5 Tubes 6 Structure 7 Sealing unit 8 Control device 9 Imaging equipment 11 Sensors 12 Reference mark pattern 13 Packaging material unit 14,14* Reference mark 14A* Reference point 15,15* Reference mark 15A* Reference point 16 Control Unit 17 Sensor equipment 18 Sensors 19 Sterilization bath 20 Packaging material coils 21 Scroll P Transmission Path Y longitudinal axis D 1 distance D 2 distance AO Overlap Area V Width D 3 distance D 4 distance T Angular position of packaging material edge 13B

Claims

1. A packaging machine for producing sealed packages from packaging material, said packaging material being fed along a conveying path (P), said packaging machine comprising: a folding unit (4) arranged along the conveying path (P) for folding the packaging material from a flat surface into a tube (5) having a longitudinal axis (Y), wherein a first edge (13B) of the packaging material partially overlaps a second edge (13A) of the packaging material; as well as - a control device (8), comprising: an imaging device (9) having a camera (11A), arranged downstream of the folding unit (4) along the conveying path (P) and configured to frame at least a longitudinal portion of the tube (5) and to generate a signal; A control unit (16) connected to the imaging device (9) and configured to measure the angular position (T) of the first edge (13B) relative to the longitudinal axis (Y) based on the signal.

2. The packaging machine according to claim 1, and further comprising a reference mark connected to a frame of the packaging machine (1), the camera (11A) being configured to frame at least a longitudinal portion of the tube (5) and the reference mark.

3. A packaging machine according to claim 1 or 2, and further comprising a sealing unit (7), which is arranged downstream of the folding unit (4) along the conveying path (P) to obtain a liquid-tight longitudinal seal in the tube (5), and the imaging device (9) is placed downstream of the sealing unit (7).

4. Packaging machine according to any of the preceding claims, wherein said control unit (16) is configured to measure said angular position (T) of a boundary of said first edge (13B) relative to said longitudinal axis (Y) based on said signal.

5. Packaging machine according to any of the preceding claims, wherein said control unit (16) is configured to measure said angular position (T) of a boundary of said first edge (13B) relative to said longitudinal axis (Y) based on said signal.

6. A method for producing sealed packages from packaging material, said packaging material being fed along a conveying path (P), said method comprising the following steps: - folding the packaging material from a flat surface into a tube (5) having a longitudinal axis (Y) such that a first edge (13B) of the packaging material partially overlaps a second edge (13A) of the packaging material; - acquiring an image of at least a longitudinal portion of the tube (5); as well as - measuring said angular position (T) of said first edge (13B) relative to said longitudinal axis (Y) based on said image.

7. Packaging method according to claim 6, comprising measuring said angular position (T) of the boundary of said first edge (13B) relative to said longitudinal axis (Y) based on said image.

8. The packaging method according to claim 6 or 7, further comprising the following steps: - continuously acquiring images of at least a longitudinal portion of the tube (5) and of the reference markings; as well as - measuring said angular position (T) of said first edge (13B) relative to said longitudinal axis (Y) based on the position of said first edge (13B) relative to the distance from said reference mark.

9. The packaging method according to any one of claims 6 to 8, and further comprising the steps of: - acquiring a reference image of at least a longitudinal portion of the tube (5) and of the reference markings; - preferably removing said reference mark; and - measuring said angular position (T) of said first edge (13B) relative to said longitudinal axis (Y) based on a comparison with said reference image.

10. The packaging method according to any one of claims 6 to 9, wherein: In case the angular position of the first edge (13B) relative to the longitudinal axis (Y) is greater than a predetermined threshold, the method comprises a further step of generating a warning signal and / or a further step of closed-loop control of the folding step.

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