Packaging machine and method for producing packages from packaging material

Abstract

A packaging machine and method for producing sealed packages from packaging material fed along a conveying path (P), comprising a packaging machine (1) arranged along said conveying path (P) and comprising a folding unit (4) for folding the packaging material from a flat shape into a tube (5) having a longitudinal axis (Y), at least one sensor (11) arranged along the forward path (P) downstream of the folding unit (4) and configured to frame at least a longitudinal portion of the tube (5) and generate a signal, a control unit (8) equipped with an imaging device (9) having in particular a camera (11), and a control unit (16) connected to the imaging device (11) and configured to measure the 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 to a packaging machine including a control device for detecting parameters of a tube formed by folding packaging material and filled with a product to be packaged, in particular to a packaging method including the step of detecting parameters of a tube formed by folding packaging material and filled with a product to be packaged. [Background technology]

[0002] As is well known, many liquid or pourable food products, such as pasteurized or ultra-high temperature (UHT) milk, tomato sauce, wine, fruit juice, etc., are sold in packages made from sterilized packaging material.

[0003] This type of package is typically produced using an automatic packaging machine which, by means of known guide elements (e.g., rollers, etc.), feeds the web of packaging material through a sterilization unit, where the web of packaging material is alternately sterilized by chemical sterilization (e.g., by applying a chemical sterilant such as an aqueous hydrogen peroxide solution) or by physical sterilization (e.g., by electron beam) in a sterilization bath.

[0004] The packaging machine further comprises a folding unit disposed downstream of the sterilization unit and configured to fold the web of packaging material to produce a continuous tube. Within the folding unit, the web of packaging material is folded from a continuous planar shape into a continuous tubular shape having a vertical axis. The web of packaging material having a planar shape is folded into a tubular shape that is continuously subdivided into a plurality of pillow packs that undergo successive mechanical folding operations to obtain completed sealed packages. The folding unit is preferably disposed within a stationary structure in which the web of packaging material is maintained in a sterile air environment. The folding unit further comprises a number of folding devices disposed in series (one after the other). By interacting with the folding devices, opposing side edge portions (or edge regions) of the web of packaging material are positioned one above the other to define overlap regions to form the tube.

[0005] The packaging machine includes a sealing unit disposed downstream of the folding unit for sealing the overlapping end portions of the web of packaging material to obtain a liquid-tight longitudinal seal within the tube.

[0006] The tube is continuously filled with the pourable food product through a dispensing conduit which extends partially within the tube and is part of the filling circuit.

[0007] The tube is finally sent to the forming and horizontal sealing unit, where the tube is gripped and horizontally sealed, then cut to form the pillow pack.

[0008] In order to ensure a good quality of transverse sealing of the tube of packaging material in the above-mentioned packaging machine, the tube must be fed with the overlap area having a predetermined angular position relative to the vertical axis and with the overlap area having a predetermined width.

[0009] Therefore, there is a strong need to accurately measure the angular position of the overlap region relative to the vertical axis of the tube. Summary of the Invention [Problem to be solved by the invention]

[0010] SUMMARY OF THE INVENTION It is an object of the present invention to provide a packaging machine for producing packages from packaging material, which does not suffer from the above-mentioned drawbacks and which is particularly easy and economical to manufacture.

[0011] A further object of the invention is to provide a packaging method for producing packages from packaging material, which method does not suffer from the above-mentioned drawbacks and is in particular easy and economical to carry out.

[0012] According to the present invention, there is provided a packaging machine and method for producing packages from packaging material in accordance with the accompanying claims.

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

[0014] [Figure 1] 1 is a perspective view, with parts removed for clarity, of a packaging machine for producing packages from packaging material in accordance with the present invention; [Figure 2] FIG. 2 is a schematic side view of a first portion of the packaging machine of FIG. 1. [Figure 3] FIG. 2 is a perspective view of a second portion of the packaging machine of FIG. 1. [Figure 4] 2 shows a first embodiment of a planar piece of packaging material for obtaining a package using the packaging machine of FIG. 1; FIG. [Figure 5] 5 is a fragmentary view showing the portion of the packaging material of FIG. 4 folded to obtain a tube. [Figure 6] 1. FIG. 3 shows a second embodiment of a planar piece of packaging material for obtaining a package using the packaging machine of FIG. [Figure 7] 7 is a partial view showing a portion of the packaging material of FIG. 6 folded into a tube. DETAILED DESCRIPTION OF THE INVENTION

[0015] Figures 1 and 2 generally disclose a packaging machine 1 for continuously producing sealed packages containing pourable food products, for example pasteurised or ultra-high temperature (UHT) milk, tomato sauce, wine, fruit juice, etc. The sealed packages are obtained from packaging material that is unwound from a reel 21 and fed along a conveying path P. When unwound from the reel 21, the packaging material has the form of a continuous planar web 20 of packaging material.

[0016] Typically, the packaging material has a multi-layer structure. More specifically, the packaging material may comprise at least one layer of fibrous material, such as a paper or cardboard layer, and at least two layers of heat-sealable plastic material, such as polyethylene, sandwiched between the layers of fibrous material. One of the two layers of heat-sealable plastic material may define the inner surface of the package that will ultimately contact the pourable product.

[0017] According to some possible non-limiting embodiments, the packaging material may also comprise a layer of gas- and light-barrier material, such as aluminum 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 fibrous material. Preferably, the packaging material may comprise a further layer of heat-sealable plastic material interposed between the layer of gas- and light-barrier material and the layer of fibrous material.

[0018] The packaging machine 1 comprises a sterilization unit 3 having a sterilization bath 19 in which a chemical sterilant, such as an aqueous hydrogen peroxide solution, is applied to a web of packaging material 20. The web of packaging material 20 is fed through the sterilization unit 3 by known guiding elements, such as rollers or similar elements.

[0019] 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 extends, preferably substantially vertically, along the conveying path P to produce a continuous tube 5. In particular, within the folding unit 4 the web of packaging material 20 is folded from a continuous planar shape into a continuous tube having a longitudinal axis Y.

[0020] The folding unit 4 is defined within a stationary structure 6 in which the web of packaging material 20 is maintained in a sterile air environment. The folding unit 4 further comprises a number of folding devices 100 arranged in succession (one after the other) along the conveying path P, each folding device 100 comprising a number of folding rollers which cooperate to fold the web of packaging material 20.

[0021] The packaging machine 1 comprises a sealing unit 7 (of a known type and not described in detail) for sealing the overlapping edges 13A, 13B of the packaging material to obtain a liquid-tight longitudinal seal within the tube 5.

[0022] The tube 5 is continuously filled with pourable food product through a filling conduit 101 which extends partially within the tube 5 and is part of a filling circuit.

[0023] The tube 5 is fed to a forming and transverse sealing device (not shown) where the tube 5 is gripped and transversely sealed to form the pillow pack 2. Finally, the pillow pack 2 is subjected to successive mechanical folding operations to obtain the finished sealed package.

[0024] The packaging machine 1 is equipped with a control device 8 configured to measure and control the angular position T of the edge 13B relative to the longitudinal axis Y (i.e., the rotation or twist of the tube 5 around the longitudinal axis Y) and / or the width of the overlap area AO defined by the overlapping portions of the packaging material edge 13A and the packaging material edge 13B.

[0025] The web of packaging material 20 is provided with a pattern of a plurality of fiducial marks 12 which are positioned one after the other along the length of the web of packaging material 20 (and the tube 5) and which provide information regarding the location of the packaging material.

[0026] Each pattern of fiducial marks 12 defines or is part of a packaging material unit 13 intended to form a respective sealed package.

[0027] 4 discloses a first embodiment of a fiducial mark pattern 12. The fiducial mark pattern 12 comprises at least two fiducial marks 14, 15. In the illustrated embodiment, the fiducial marks 14, 15 are dedicated marks having a substantially square shape. Alternatively, the fiducial marks 14, 15 may be pre-existing marks (e.g., splice marks, barcodes, etc.).

[0028] The reference mark 14 is located close to the packaging material edge 13A. The reference mark 14 has a reference zone 14A, for example an edge zone, facing the edge 13A.

[0029] A distance D1 is defined between the packaging material edge 13A and the reference zone 14A, and this distance D1 is different from zero.

[0030] The reference mark 15 is located close to the packaging material edge 13B. In particular, the reference mark 15 preferably has a reference zone 15B that corresponds to the packaging material edge 13B.

[0031] The second edge 13A may comprise a portion of the packaging material between the boundary of the second edge 13A and the reference mark 14.

[0032] The first edge 13B of the packaging material may be at least partially positioned over the second edge 13A, i.e. the (outer) boundary of the packaging material edge 13B may be positioned over the second edge 13A.

[0033] The control device 8 comprises a detection device 17 having at least a sensor 18. According to a first embodiment, the sensor 18 is adapted to edge a longitudinal portion of the web of packaging material 20. Preferably, the longitudinal portion of the web of packaging material 20 edged by the sensor 18 comprises the packaging material unit 13. Even more preferably, the longitudinal portion of the web of packaging material 20 edged by the sensor 18 corresponds to the packaging material unit 13. In one embodiment, the sensor 18 is preferably a camera 18A.

[0034] The detection device 17 is configured to measure the distance D1 of each packaging material unit 13 when the packaging material has a planar shape. Preferably, the detection device 17 is arranged upstream of the sterilization unit 3.

[0035] The control device 8 further includes an imaging device 9 as disclosed in Fig. 3. Preferably, the control device 8 further includes a fixed frame having a movable bracket (not shown) that supports the imaging device 9. The movable bracket is rotatable about an axis between a working position in which the imaging device 9 faces the tube 5 and is positioned close to the tube 5, and a rest position in which the imaging device 9 does not face the tube 5 and is positioned away from the tube 5.

[0036] The imaging device 9 comprises at least a sensor 11 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. More preferably, the longitudinal portion of the web 20 of packaging material framed by the sensor 18 corresponds to the packaging material unit 13.

[0037] When the web 20 of packaging material is folded from a planar shape into a (e.g., substantially) tubular shape, the packaging edge 13B at least partially overlaps the packaging edge 13A, defining an overlap area AO formed by the overlap of the lateral portions of the packaging material. During the pre-setting and design phase of the packaging machine 1's operating cycle, a reference value for the width of the overlap area AO is defined. In other words, the reference value is a preferred or optimal value corresponding to the correct operating state of the packaging machine 1. Importantly, the distance D1 must be selected (when printing the mark 14 on the packaging material) to be greater than the reference value. Furthermore, a distance D2 is defined between the reference zone 15B (which, in the illustrated embodiment, corresponds to the packaging edge 13B) and the reference zone 14A. The distance D2 is measured when the web 20 of packaging material has a (e.g., substantially) tubular shape, as disclosed in FIG. 5 . The distance D2 is measured by the imaging device 9, specifically for each packaging material unit 13.

[0038] Finally, the control device 8 comprises a control unit 16 connected to both the imaging device 9 and the detection device 17. In particular, the imaging device 9 is designed to generate a signal indicative of the distance D2 of each packaging material unit 13 and send it to the control device 16. In turn, the detection device 17 is designed to generate a signal indicative of the distance D1 of each packaging material unit 13 and send it to the control unit 16. The control unit 16 calculates the actual value of the overlap area AO through the difference between the distance D1 and the distance D2 of each packaging material unit 13.

[0039] The control unit 16 further compares the actual value of the overlap area AO with a reference value, and if the difference between the actual value of the overlap area AO and the reference value exceeds a predefined threshold, the control unit 16 is designed to generate a warning signal to indicate an undesirable significant deviation from the reference value.

[0040] According to a preferred embodiment, the control unit 16 is implemented to control the folding unit 4 and the sealing unit 7 based on the actual value of the overlap area AO.

[0041] According to a further embodiment, not shown, the pattern of fiducial marks 12 comprises the above-mentioned fiducial marks 14, and the fiducial marks 15 are packaging material edges 13B. In other words, the pattern of fiducial marks 12 does not comprise a dedicated fiducial mark 15, but the fiducial marks 15 are defined by the packaging material edges 13B. The distance D2 measured by the imaging device 9 is defined between the packaging material edges 13B and the reference zone 14A.

[0042] 6 and 7 disclose a second embodiment of the pattern 12 of fiducial marks.

[0043] The fiducial mark pattern 12 comprises at least two fiducial marks 14*, 15*. In the illustrated embodiment, the fiducial marks 14*, 15* are pre-existing marks (e.g., splice marks, barcodes, etc.). Alternatively, the fiducial marks 14*, 15* may be dedicated marks.

[0044] Fiducial mark 14* is located adjacent to packaging material edge 13A, and fiducial mark 15* is located adjacent to packaging material edge 13B.

[0045] First edge 13B may comprise the portion of the packaging material between the boundary of first edge 13B and fiducial mark 15*. Second edge 13A may comprise the portion of the packaging material between the boundary of second edge 13A and fiducial mark 14*.

[0046] For example, the (outer) boundary of edge 13B of the packaging material may be positioned above second edge 13A.

[0047] According to the embodiment disclosed in FIGS. 6 and 7, the sensor 18 is a camera 18A, or alternatively a through beam sensor 18, preferably a through beam laser sensor 18.

[0048] The detection device 17 is configured to measure the width V of each packaging material unit 13 when the packaging material has a planar shape, i.e., the width from packaging material edge 13A to packaging material edge 13B of the web 20 of packaging material.

[0049] Furthermore, the producer of the web 20 of packaging material provides information about the packaging material, such as the distance D3 between the fiducial marks 14*, 15*. More specifically, the producer of the web 20 of packaging material provides a distance D3 defined between the reference point 14A* of the fiducial mark 14* and the reference point 15A* of the fiducial mark 15*, in particular the ends. The distance D3 therefore has a predefined value that is stored in the control unit 16.

[0050] Imaging device 9 is configured to measure distance D4 between fiducial mark 14* and fiducial mark 15*, for example, when the packaging material is folded (e.g., substantially) into a tube. More specifically, distance D4 is defined between reference point 15A* of fiducial mark 15* and reference point 14A* of fiducial mark 14* on tube 5.

[0051] The imaging device 9 is designed to generate and transmit to the control unit 16 a signal indicative of the distance D4 of each packaging material unit 13. The control unit 16 then calculates the total circumference of each packaging material unit 13 by adding the distance D3 to the distance D4. Finally, the control unit 16 calculates the actual value of the overlap area AO using the difference between the width V and the total circumference of each packaging material unit 13 obtained as described above.

[0052] Again, if the difference between the actual value of the overlap area AO and the reference value exceeds a predefined threshold, the control unit 16 is designed to generate a warning signal to indicate an undesirable significant deviation from the reference value. According to a preferred embodiment, the control unit 16 is realized 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.

[0053] The image of each packaging material unit 13 provided by the imaging device 9 is used to measure the angular position T of the packaging material edge 13b formed relative to the longitudinal axis Y, which represents the rotation or twist of the tube 5 about the longitudinal axis Y.

[0054] According to a first embodiment, the camera 11A is adapted to continuously acquire images of at least a longitudinal portion of the tube 5 and of a fiducial marker (not shown). In particular, the camera 11A is adapted to frame the longitudinal portion of the tube 5 and the fiducial marker. The fiducial marker is connected to the frame of the packaging machine 1 and is therefore arranged in a fixed position with respect to the tube 5 advancing along the advance path P. According to a possible embodiment, the fiducial marker is defined by a slit in a bracket connected to the frame of the packaging machine 1.

[0055] For each image acquired by camera 11A, control unit 16 is configured to determine the angular position T of packaging material edge 13B relative to longitudinal axis Y based on the position of said packaging material edge 13B relative to the reference marker. In particular, control unit 16 is configured to determine the angular position T of packaging material edge 13B relative to longitudinal axis Y based on the distance of packaging material edge 13B from the reference marker.

[0056] In one or more embodiments, 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 position of the (outer) boundary of the packaging material edge 13B relative to the reference marker.

[0057] According to a further preferred embodiment, the camera 11A is adapted to acquire a reference image in a pre-setup phase. The reference image comprises at least a longitudinal portion of the tube 5 and a movable fiducial marker. The fiducial marker is connected to the frame of the packaging machine 1. According to a possible embodiment, the fiducial marker is defined by a slit in a bracket that is removably connected to the frame of the packaging machine 1. After acquiring the reference image in the pre-setup phase, the movable fiducial marker is removed from the packaging machine 1 and the reference image is saved in the control unit 16.

[0058] 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 the displacement of the packaging material edge 13B relative to a reference position of the packaging material edge 13B in the reference image.

[0059] In both embodiments, assessment of the correct positioning of the packaging material edge 13B allows the user to determine whether the tube 5 to be formed is correctly positioned relative to the longitudinal axis Y. According to a preferred embodiment, the control unit 16 is actually realized to control the folding unit 4 and the sealing unit 7 based on the angular position T of the packaging material edge 13B.

[0060] If the angular position T of the packaging material edge 13B formed relative to the longitudinal axis Y is greater than a predetermined threshold, the control unit 16 is designed to generate a warning signal indicating an undesirable and significant deviation.

[0061] 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.

[0062] It is clear that the same image provided by the camera 11A for each packaging material unit 13 enables the control device 8 to measure and control both the actual value of the overlap area AO and the twist of the tube 5 around the longitudinal axis Y.

[0063] 1 packaging machine 2 pack 3 Sterilization Unit 4 Folding unit 5 tubes 6 Fixed structure 7 Seal Unit 8 Control Device 9. Imaging device 11 Sensors 12 Fiducial Mark Pattern 13 Packaging Materials Unit 14, 14* fiducial marks 14A* Reference Point 15, 15* fiducial marks 15A* Reference point 16 Control Unit 17 Detection equipment 18 Sensors 19 Sterilization tank 20 Packaging Materials Web 21 reels P Transport route Y longitudinal axis D1 distance D2 distance AO overlap area V width D3 distance D4 distance T Angular position of packaging material edge 13B

Claims

1. 1. A packaging machine for producing sealed packages from packaging material supplied along a conveying path (P), comprising: a folding unit (4) disposed along the conveying path (P) for folding the packaging material from a planar shape into a tube (5) having a longitudinal axis (Y), the first edge (13B) of the packaging material being at least partially disposed over the second edge (13A) of the packaging material; a control device (8), The control device (8) an imaging device (9) arranged along the conveying path (P) downstream of the folding unit (4), the imaging device having a camera (11A) 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, based on the signal, an angular position (T) of the first edge (13B) relative to the longitudinal axis (Y); A packaging machine comprising:

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

3. The apparatus further includes a sealing unit (7) disposed downstream of the folding unit (4) along the conveying path (P) to obtain a liquid-tight longitudinal seal within the tube (5), and the imaging device (9) is disposed downstream of the sealing unit (7). The packaging machine according to claim 1.

4. the control unit (16) is configured to determine, based on the signal, the angular position (T) of the boundary of the first edge (13B) relative to the longitudinal axis (Y); The packaging machine according to any one of claims 1 to 3.

5. the control unit (16) is configured to determine, based on the signal, the angular position (T) of the boundary of the first edge (13B) relative to the longitudinal axis (Y); The packaging machine according to any one of claims 1 to 4.

6. A method for producing sealed packages from packaging material fed along a conveying path (P), comprising the steps of: folding the packaging material from a planar shape 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 said tube (5); measuring an angular position (T) of said first edge (13B) relative to said longitudinal axis (Y) based on said image; A manufacturing method comprising:

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

8. Sequentially acquiring images of at least a longitudinal portion of the tube (5) and fiducial markers; measuring the angular position (T) of the first edge (13B) relative to the longitudinal axis (Y) based on the position of the first edge (13B) relative to the distance from the fiducial marker; The method of claim 6 or 7, further comprising:

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

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

Images