Method and alignment station for aligning filled stand-up pouches at the top

Abstract

The invention relates to a method and to an alignment station for aligning top regions formed on stand-up pouches for subsequently sealing the latter by means of a weld seam. The stand-up pouches, which are filled with product and are open at the top, are conveyed cyclically to grippers which are stationary in terms of transport, grip lateral edge portions of each top region and pull these apart in such a way that the front faces and the rear faces of the top regions are moved towards one another. Furthermore, the front faces and rear faces are subsequently fixed by means of at least one movable fixing strip accompanying each of the stand-up pouches for further transport for sealing purposes. In this way, even particularly flexible pouch materials having low rigidity can subsequently be sealed with high quality.

Description

[0001] Method and alignment station for aligning filled stand-up pouches at the top

[0002] The invention relates to a method and an alignment station, each for aligning head areas formed on filled stand-up pouches.

[0003] As is well known, flexible stand-up pouches for liquid products, such as beverages, can be manufactured from a multi-layered film composite and, after filling, sealed at the top by a sealing strip that moves with the pouch during transport. This involves applying external pressure to the front and back of the pouch, pressing them flat against each other. A wrinkle-free top seal can then be created using standard film welding processes. This requires a certain degree of rigidity in the film material, particularly at the top, which can be achieved, for example, by adding a stiffening layer of aluminum.

[0004] For environmental reasons and in light of potential future developments in environmental regulations, it is increasingly advisable to largely avoid using aluminum in composite materials. Due to the reduced stiffness of the pouches, particularly in the head area during hot filling, the front and back sides can no longer be reliably pressed together by the sealing strips as described above, making it impossible to reliably produce a wrinkle-free head seal.

[0005] Therefore, there is room for improvement.

[0006] The stated problem is solved by a method and an alignment station according to the independent claims. Advantageous embodiments are specified, inter alia, in the dependent claims.

[0007] The described process is used to align the head sections of stand-up pouches for subsequent sealing by means of a heat seal. The product-filled, open-top stand-up pouches are conveyed intermittently to stationary grippers. These grippers grasp the lateral edge sections of the respective head section and pull them apart, bringing the front and back of the head sections towards each other. The aligned front and / or back sections are then fixed or stabilized for further transport to the sealing area by at least one moving, controlled fixing strip that travels with the stand-up pouch. In other words, the grippers pull the lateral edge sections of the respective head section apart, closing the filling opening formed by the upper edges of the front and back.

[0008] In this process, the front and back sides of the head areas can be moved so close together that their upper edges eventually lie against each other, at least in sections and especially essentially along their entire length.

[0009] This alignment is then fixed or stabilized by supporting or clamping at least one fixing strip (possibly with a suitable counter bearing) that is movable and, in particular, pivotable on the respective stand-up pouch.

[0010] A single, movable fixing strip of this type supports or clamps the respective bag(s) of a corresponding transverse row, preferably actively from the front or rear, in conjunction with a rigid support structure arranged on the opposite side of the bag(s). Movable fixing strips, especially those pivotable, can, in contrast, actively support or clamp the bag(s) of a transverse row from both the front and rear.

[0011] Individual fixing strips or pairs of such fixing strips that move towards the bags can each be assigned to several conveying tracks (processing tracks) or to a transverse row of stand-up pouches extending over them, for example 6 to 24 conveying tracks.

[0012] The fixing strip does not contribute to closing the filling opening, but merely holds the head area, which has been previously aligned by the grippers, in shape, particularly in such a closed state that the front and back sides are in contact with each other.

[0013] The filling opening is therefore no longer closed by a closing strip with a compressive force acting on the front and back from the outside, but by a tensile force directed orthogonally to it. The stiffness of the film used is less relevant to the process, as it no longer needs to transfer the force required to align the front and back sides to the lateral edge areas of a side seal. Consequently, the subsequent weld seam sealing of the filling opening is reliably wrinkle-free even with films of low stiffness.

[0014] Preferably, the gripper fingers on the grippers are moved in a vertical plane parallel to the transport direction of the conveying device by means of a motor drive individually designed on the gripper. This enables space-saving and precise actuation of the grippers for closing and opening, as well as adjustment of the closing force to the respective film material.

[0015] The gripper fingers preferably grip from above, particularly vertically from above, and then preferably alternate intermittently between an open position, in which the stand-up pouches can pass underneath the grippers, and a closed position, in which they grip the top areas. The grippers can then be operated in a structurally simple, vertically stationary position in production.

[0016] In their open position, the opening angle of each gripper, i.e., the total opening angle enclosed by its opposing gripper fingers, is, for example, at least 90°, preferably at least 150° (compared to the closed position at 0°). Such opening angles not only allow for easy transport of the bags beneath the open grippers, but also simplify gripping the head areas held open by the product inside, the shape and position of which can vary due to the flexible bag material.

[0017] Alternatively (to grippers that open wide from above and are otherwise vertically stationary), it would also be conceivable to lower the grippers in an open position from above onto the corresponding head areas of the bags in a sequential manner. The grippers could then open from above and / or laterally from the outside towards the bags, for example, also diagonally from above / outside. The alignment station would then include a lifting mechanism for preferably raising and lowering all the grippers simultaneously.

[0018] The grippers are preferably moved transversely to the transport direction of the transport vehicle for moving the pouches apart and together in pairs. This enables efficient closing of the stand-up pouches, which are usually oriented transversely during transport.

[0019] The stand-up pouches can be conveyed in several processing / conveyor lanes under their respective pairs of grippers. Preferably, after closing, the grippers on the left side of the conveyor lanes are mechanically coupled to each other, and the grippers on the right side of the conveyor lanes are mechanically coupled to each other and moved in groups. Each group can then be efficiently moved by a single dedicated drive, such as a servo motor. With the aid of an additional gearbox, both groups could also be moved by a single drive.

[0020] For example, 6 to 24 conveyor tracks are arranged side by side. It is particularly advantageous, after the grippers have closed, to mechanically couple the grippers on the left with respect to the conveyor tracks and mechanically couple the grippers on the right with respect to the conveyor tracks, each in groups.

[0021] Preferably, the front and back sides of the head areas below the pulled-apart grippers are supported and / or pressed together by at least two fixing strips movable towards each other until subsequent sealing.

[0022] The fixing strips, which move along with the bags, could, for example, be actuated in a generally known manner by means of at least one stationary control cam or a stationary actuator in the periphery of the conveyor after the grippers have moved apart. This allows the head sections to be transported relatively easily and with sufficient shape stabilization for subsequent welding.

[0023] Stand-up pouches, for example, consist of multi-layered plastic films, primarily made of PP or PE. This can be understood to mean that the plastic films do not include a stiffening aluminum layer, whereas aluminum vapor deposition or auxiliary plastics for creating gas barriers or for bonding would be conceivable.

[0024] The stand-up pouches are applied in the described manner, particularly after hot filling. This means that the product immediately filled into the pouches is still at a temperature suitable for hot filling of beverages such as juices or similar products. This elevated temperature reduces the stiffness of thermoplastic pouch materials, such as PE or PP, making the described method particularly advantageous downstream of hot filling. However, the described method is also advantageous after cold filling, as the filled product always presses down on the pouch base and would otherwise deform the top area and hinder proper sealing.

[0025] A further advantage is a method for sealing product-filled stand-up pouches, wherein the product is still heated, particularly as a result of hot filling, and wherein the top-side filling openings of the stand-up pouches are drawn closed using the alignment method according to at least one of the described embodiments and then sealed in such a fixed orientation after cycle-by-cycle transport by means of a foil weld seam.

[0026] The described alignment station serves to align the head sections formed on filled stand-up pouches for their subsequent sealing by means of a weld seam, comprising: a transport means for the cycle-wise transport of the filled stand-up pouches; grippers arranged stationary above the stand-up pouches for transport purposes; and at least one fixing bar that travels with the stand-up pouches, wherein the grippers are arranged and automatically controlled in such a way that they grasp lateral edge sections of the respective head section and pull them away from each other, thereby moving the front and back sides of the head sections towards each other, and wherein the respective fixing bar is arranged and automatically controlled in such a way that it can fix the previously moved front and / or back sides for further transport to sealing.

[0027] The individual grippers can each have gripper fingers movable in a vertical plane parallel to the transport direction of the transport means for closing or gripping, and a motor drive for actuating the gripper fingers.

[0028] The gripper fingers are preferably arranged and automatically controlled in such a way that they grip from above and alternate between an open position, in which the stand-up pouches can pass below the grippers, and a closed position, in which they grip the head areas.

[0029] Preferably, the grippers are arranged to be displaceable in pairs, transverse to the direction of transport of the means of transport, for moving them apart / together.

[0030] The alignment station can comprise a plurality of grippers, which are assigned in pairs to the adjacent conveyor tracks, in particular 6 to 24, for the stand-up pouches. Preferably, all grippers on the left with respect to the respective conveyor track are moved together by means of a first transverse connecting structure, and all grippers on the right with respect to the respective conveyor track are moved together by means of a second transverse connecting structure. The respective connecting structure can be a crossbeam, a slide, or the like.

[0031] The conveyor can include pairs of leading and trailing fixing bars for each stand-up pouch, which are arranged and controlled in such a way that they support and / or compress the front and back sides of the head areas below the grippers, which are moved apart in pairs, especially until the subsequent sealing.

[0032] A filling system for stand-up pouches is also advantageous, comprising: a filling station for filling, in particular hot filling, the stand-up pouches with a liquid product; downstream of this, the alignment station according to at least one of the described embodiments; further downstream of this, a sealing station for producing top seals above the fixing strips by means of film welding; and at least one conveyor extending between them and driven intermittently with support structures for the upright reception of each stand-up pouch.

[0033] A preferred embodiment of the invention is illustrated in the drawings. The drawings show:

[0034] Fig. 1 shows a schematic front view of a treatment track of the alignment station;

[0035] Fig. 2 shows a schematic side view of the alignment station; and

[0036] Fig. 3 shows a schematic representation of a filling plant with the alignment station.

[0037] As can be seen in Figures 1 and 2 together, the alignment station 1 for aligning head areas 3 formed on flexible stand-up pouches 2 (hereinafter also referred to as pouches 2) for their subsequent sealing by means of a weld seam comprises: at least one, for example, belt- or chain-shaped conveyor 4 for the stepwise conveying of the upstream-filled stand-up pouches 2 in a predetermined work cycle; grippers 5 and right grippers 6 arranged in a conveying-technical position above the stand-up pouches 2 thus conveyed; and fixing bars 7 that travel along with the pouches 2 during conveying.

[0038] The grippers 5, 6 are arranged transversely to the conveying direction 4a and are electronically controlled, so that they grasp pairs of assigned lateral edge sections 3a of the respective head section 3 and pull them apart, thereby moving the corresponding front 3b and back 3c of the head sections 3 towards each other. This essentially closes the head-side filling opening 2a of the stand-up pouches 2. In Fig. 1, the pulled-apart state of the head section 3 is schematically indicated by a dashed outline 3'.

[0039] Fig. 2 shows in the area of ​​the alignment station 1 a stand-up pouch 3 with the filling opening already closed in an associated work cycle (there without reference numeral) and behind it a stand-up pouch 3 with the filling opening 2a still open from the previous product filling, which is then closed accordingly in the next work cycle.

[0040] The grippers 5, 6 each have pivotable gripper fingers 9 in a vertical plane parallel to the conveying direction 4a and individual drives 10 for (here in pairs) closing / opening the gripper fingers 9. These drives can be, for example, servo motors. In the fully open position 11 (shown with dashed lines for differentiation) of the grippers 5, 6, the bags 2 can pass under the gripper fingers 9 without collision. In the fully closed position 12, the gripper fingers 9 press the front 3b and back 3c together in the lateral edge areas 3a, which, for example, include side seals 2b, in a force-fit manner.

[0041] The gripper fingers 9 can be pivoted relative to the closed position 12, for example, by a total opening angle 11a of at least 90° and, in particular, at least 150° into the open position 11, in order to convey the bags 2 underneath without collision. Opening angles of the grippers 5, 6, i.e., total opening angles 11a between the gripper fingers 9, in the range of 150 to 180° are particularly advantageous (corresponding to opening angles of 75 to 90° of the individual gripper fingers 9 with respect to their closed position 12 or a central axis of the grippers 5, 6).

[0042] The alignment station 1 preferably comprises a plurality of adjacent treatment tracks or conveying tracks 4b (see Fig. 3) for the stand-up pouches 2, of which only one track is shown representatively in Figs. 1 and 2. It is then advantageous to couple all the grippers 5 on the left side of the station together by a first connecting structure 13 extending transversely to the conveying direction 4a, and all the grippers 6 on the right side together by a corresponding second connecting structure 14, and consequently to move them together in groups when the lateral edge areas 3a are pulled apart (see arrows between 15 and 16 in Fig. 1, not to scale). The connecting structures 13, 14 (omitted in Fig. 2 for clarity) can be or comprise carriers, slides, or other transport elements, optionally coupled appropriately.

[0043] Four conveyor tracks 4b are shown here as an example for better understanding. Depending on the required production output, there could instead be, for example, 6 to 24, or in particular 8 to 20, conveyor tracks 4b side by side or used simultaneously.

[0044] The connecting elements 13, 14 can be assigned separate motorized actuators 13a, 14a (Fig. 3) or a common actuator with gearbox (not shown). These can be, for example, servo motors.

[0045] The grippers 5 and 6 are moved back and forth in synchronized cycles with the conveyor 4 between a paired initial position 15 and a paired final position 16 (closed position), controlled electronically. In the initial position 15, the grippers 5 and 6 are positively locked onto their lateral end sections 3a and then moved laterally to the final position 16. After the head section 3 is aligned and fixed with the locking bars 7, the grippers 5 and 6 are opened again and moved back to the initial position 15 for the next work cycle.

[0046] Similarly, it would be conceivable in principle to lower all grippers 5, 6 in an open position onto the bags 2 positioned below, close them, and after the grippers 5, 6 have moved apart in pairs and the bags have been secured with the fixing bars 7, reopen them and raise them sufficiently so that the bags 2 can pass underneath. The alignment station 1 could include at least one lifting mechanism (not shown) for this purpose, allowing the grippers 5, 6 to be lowered and raised simultaneously. The grippers 5, 6 could then also grip the edge sections 3a laterally from the outside (not shown).

[0047] The fixing bars 7 are arranged and controlled so that they can pivot or, if necessary, slide in the conveying direction 4a, such that they fix the front and back sides 3b, 3c, which have been moved towards each other by means of the grippers 5, 6, to each other for further transport to sealing by means of lateral support and / or clamping in a manner suitable for the bag material. The fixing bars 7 then extend transversely, preferably across all existing conveying tracks 4b.

[0048] The fixing bars 7 run together with support frames 17 and the stand-up pouches 2 held by them on the conveyor 4. The mechanical design and drive of the fixing bars 7 can in principle correspond to that of known closing bars, but their control in the above sense is only for fixing the previously aligned front and back sides 3b, 3c, not for moving them together or closing the filling opening 2a.

[0049] In principle, the described fixation could also be achieved with only one movable fixing strip 7, which could then interact, for example, with a rigidly moving strip (not shown). However, handling the stand-up pouches 2 upstream is facilitated by two fixing strips 7 that are movable relative to each other (and still open at that point).

[0050] The conveyor-stationary grippers 5, 6 grip the stand-up pouches 2 filled with a liquid and, in particular, due to the previous filling, still hot product 18, for example a beverage, essentially at their side seals 2b, which end in the lateral edge sections 3a of the head area 3.

[0051] A further advantage is that the grippers 5, 6 are stationary and thus permanently arranged at the alignment station 1 and, unlike the fixing bars 7, are therefore not required in large numbers at each individual bag holder, i.e., in this case, the support frames 17. As can be seen in Fig. 3, the alignment station 1 is part of a filling system 20, which also includes at least one upstream filling station 21 and a downstream sealing station 22. In the filling station 21, the liquid product 18, for example, a beverage, is filled into the stand-up pouches 2 in a generally known manner. In particular, this is a hot filling process, although the described method and the alignment station 1 can also be used advantageously after cold filling. In the sealing station 22, the upper edges of the stand-up pouches 2, i.e., their previously drawn-on head areas 3a, are sealed by heat sealing.Known devices and methods can be used for this purpose, so they will not be discussed further here.

[0052] The filling system 20 and the alignment station 1 it comprises operate in a single work cycle in which the conveying and processing of the stand-up pouches 2 alternate stepwise in a manner known in principle. Programmable electronic control devices of known designs can be used for this purpose, for example, to synchronize the respective drives for the conveyor 4 and for opening / closing as well as for moving the grippers 5, 6 apart / together in a suitable manner within the work cycle.

[0053] The described alignment of the head areas 3 using stationary conveyor grippers 5, 6 can thus be integrated relatively easily and in a space-saving manner between a filling station 21 and a sealing station 22 for heat sealing stand-up pouches 2 made of flexible film material. The alignment station 1 can be easily scaled for this purpose, depending on the number of processing lanes or conveyor lanes 4b required.

Claims

Claims 1. Method for aligning head areas (3) formed on stand-up pouches (2) for their subsequent sealing by means of a weld seam, wherein the stand-up pouches, which are filled particularly hot with product (18) and are open at the top, are conveyed intermittently to stationary grippers (5, 6) and the grippers grasp lateral edge sections (3a) of the respective head area and pull them away from each other so that the front and back sides (3b, 3c) of the head areas are moved towards each other, and wherein the front and back sides are then fixed for further transport to sealing by means of at least one fixing strip (7) moving with the stand-up pouches.

2. Method according to claim 1, wherein gripper fingers (9) provided on the grippers (5, 6) are moved towards each other in a vertical plane (8) parallel to the conveying direction (4a) of the stand-up pouches (2) by means of a motor drive (10) formed on the respective gripper to close the grippers.

3. Method according to claim 1 or 2, wherein the grippers (5, 6) grip from above and gripper fingers (9) thereon alternate between an open position (11) in which the stand-up pouches (2) can pass below the grippers and a closed position (12) in which they grip the head areas (3).

4. Method according to one of the preceding claims, wherein the grippers (5, 6) are moved transversely to the conveying direction (4a) of the stand-up pouches (2) for moving them apart / together in pairs.

5. Method according to one of the preceding claims, wherein the stand-up pouches (2) are conveyed in several, in particular 6 to 24, conveying lanes (4b) under a respective pair of grippers (5, 6), and wherein, after closing, the grippers (5) on the left with respect to the conveying lanes are mechanically coupled to one another and the grippers (6) on the right with respect to the conveying lanes are mechanically coupled to one another and moved in groups.

6. Method according to one of the preceding claims, wherein the front and back sides (3b ,3c) of the head regions (3) are supported and / or pressed together below the pulled-apart grippers (5, 6) by at least two fixing strips (7) movable towards each other until subsequent sealing.

7. A method according to any one of the preceding claims, wherein the stand-up pouches (2) consist of multilayer plastic films, in particular substantially only of PP or PE.

8. A method for sealing stand-up pouches (2) filled with a liquid, in particular heated product (18), wherein the top-side filling openings (2a) of the stand-up pouches are drawn closed by the method according to at least one of the preceding claims and sealed in such a fixed orientation by means of a film weld seam after intermittent transport.

9. Alignment station (1) for aligning head sections (3) formed on stand-up pouches (2), especially those filled with hot liquid, for their subsequent sealing by means of a weld seam, comprising: a conveyor (4) for conveying the stand-up pouches intermittently; grippers (5, 6) arranged stationary above the stand-up pouches for transport purposes; and at least one fixing bar (7) moving with the stand-up pouches, wherein the grippers are arranged and controlled in such a way that they grasp lateral edge sections (3a) of the respective head section and pull them away from each other, thereby moving the front and back sides (3b, 3c) of the head sections towards each other, and wherein the fixing bar is arranged and controlled in such a way that it can fix the front and back sides moved towards each other for further transport to sealing.

10. Alignment station according to claim 9, wherein the grippers (5, 6) each have gripper fingers (9) movable in a vertical plane (8) parallel to the conveying direction (4a) of the conveyor (4) and a motor drive (10) associated therewith.

11. Alignment station according to claim 9 or 10, wherein the grippers (5, 6) comprise gripper fingers (9) arranged and controlled in such a manner as to be movable and / or are arranged vertically movable on a lifting mechanism in such a manner as to alternate between an open position (11) in which the stand-up pouches (2) can pass below the grippers and a closed position (12) in which they grip the head regions (3) in a cycle.

12. Alignment station according to claim 10 or 11, wherein the gripper fingers (9) in a fully open position (11) have a total opening angle (11a) to each other of at least 90° and in particular of at least 150°.

13. Alignment station according to any one of claims 9 to 12, wherein the grippers (5, 6) are assigned in pairs to adjacent, in particular 6 to 24, conveyor tracks (4b) for the stand-up pouches (2), and further comprising a first transverse connecting structure (13) for jointly moving the grippers (5) on the left with respect to the conveyor tracks and a second transverse connecting structure (14) for jointly moving the grippers (6) on the right with respect to the conveyor tracks.

14. Alignment station according to any one of claims 9 to 13, wherein the conveyor (4) comprises fixing bars (7) that precede and trail the stand-up pouches (7) in pairs, the fixing bars being arranged and controlled in such a way that they support and / or compress the front and back sides (3b, 3c) of the head regions (3) below the grippers (5, 6) that have moved apart in pairs, in particular until the subsequent sealing.

15. Filling system (20) for stand-up pouches (2), comprising: a filling station (21) for filling, in particular hot filling, the stand-up pouches with a liquid product (18); downstream of this, the alignment station (1) according to one of claims 9 to 14; further downstream of this, a sealing station (22) for producing top seals above the fixing strips (7) by means of foil welding; and at least one conveyor (4) extending between them and driven intermittently with support frames (17) for the upright reception of each stand-up pouch.

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