Sealing apparatus and method for sealing packages

Abstract

The invention relates to a device and a method for sealing packages on a flat-bed machine, wherein the packages are formed from a base film web (1) and a water-soluble cover film web (2). The sealing device comprises a liquid input for an aqueous liquid (3), at least one moistening unit (4) and a pressing device for pressing and sealing the cover film web (2) to the base film web (1) perpendicularly. The moistening unit (4) has a moistening roller (8) and a spraying device (10) for the aqueous liquid (3), wherein the moistening unit (4) is switchable between a first operating state and a second operating state. In the first operating state, the moistening roller acts onto the cover film web at a roller moistening site. In a machine standstill or after a machine standstill, the sealing device is in the second operating state, wherein the spraying device acts onto a spraying section of the cover film web in an input region, which is between the roller moistening site and a sealing site.

Description

TECHNICAL FIELD

[0001] The invention relates to a sealing device for sealing packages and to a method for operating such a sealing device. BACKGROUND

[0002] Household detergents or washing agents are increasingly packaged in water-soluble packages in the form of a powder or a liquid. The package consists of a water-soluble film and contains a unit dose of the detergent or washing agent as a filling. The filled and sealed package unit is placed into a washing machine or dishwasher. Upon contact with water, the film package dissolves and releases the defined amount of the contents.

[0003] In the manufacture of such package units, a base film web and a cover film web are used, which are formed from water-soluble films. The base film web is usually deep-drawn into a corresponding negative mold under the action of heat and vacuum. By means of the molding process, cavities are produced in the base film web, which are filled with the filling. Subsequently, the cover film web is lidded onto the base film web. The filling in the mold is enclosed by means of the sealing of the two films. Finally, the sealed package units are separated from the continuous film web, so that they can be used individually by the user.

[0004] For sealing such packages, in addition to the heat sealing methods known per se for films, water sealing is also considered. On a drum machine, in which the negative molds are arranged on a surrounding drum, a moistening unit with a felt roller is used, by means of which water is applied to the cover film. The moistened felt roller rolls over the water-soluble film web, thus dissolving the surface portion of the film web. The cover film with the partially dissolved surface is then pressed onto the prepared base film by means of a press roller, wherein the partial dissolution of the film surface facilitates the sealing. A device and a method of this type are known, for example, from GB 2 475 538 A. Due to the cylindrical drum shape, the filling and sealing must be carried out directly one after the other and next to the upper apex of the drum, so that the filled product remains in the deep-drawn cavities and does not come out. This limits the capacity of this machine type.

[0005] As an alternative to the described drum machine, a flat-bed machine is used, in which format plates, similarly to the shaped negative molds, move in a surrounding manner toward a conveyor belt and here carry out horizontal movements during the process steps important for deep-drawing, filling and sealing. In this respect, compared to the drum machine, a greater application quantity is achieved per unit of time, since one or more format plates with a plurality of negative molds can simultaneously go through a process step. The latter, however, requires the individual process workstations along the horizontal movement path to be located relatively far apart from one another.

[0006] In the event of a production interruption, i.e. in the event of a temporary shutdown of the machine, this distancing can be seen to be disadvantageous. There is a long section of the covered film web that is moistened between the moistening device and the sealing point, which has not yet been covered and begins to dry out on shutdown. On restart of the machine after the shutdown, this film section no longer has the desired moisture and can no longer be covered without difficulty in the required quality. Products that are not properly closed are produced, the filling material can come out of these products and dirty the packaging machine, which can lead to a renewed shutdown of the machine. Furthermore, the products that are not properly closed cannot be properly transported away in the machine discharge.

[0007] It is not possible to re-moisten the critical film section that has dried out with a moistening roller. As an alternative to this, EP 3 323 740 B1 describes a device and a method in which an electromechanical spraying system with a row of outlet nozzles is used to spray a water-containing liquid contactlessly onto the covered film web, similar to an inkjet printer. In everyday operation, the electromechanical spraying system moistens the covered film web on the circumference of the press roller, i.e. not far in front of the sealing point. A certain film section is thus left between the moistening point and the sealing point, which dries out in the event of a machine shutdown and can lead to the above-mentioned consequences on subsequent restart, in order to overcome this, EP 3 323 740 B1 also describes the possibility of a pivotable design of the electromechanical spraying system, which should be used on restart. But pivoting means for re-moistening that the row of nozzles must be turned from the original moistening point to and onto the dried-out area below the press roller, with the result that not only the covered film web, but also the deep-drawn base film web with the already filled products, is likewise undesirably moistened. Expensive countermeasures are required. The problem of the restart is not satisfactorily solved in EP 3 323 740 B1. SUMMARY

[0008] The task of the present application is to expand the design of such a sealing device in such a way that better restart properties are achieved.

[0009] The task is solved by a sealing device with the features of the present application.

[0010] Furthermore, the task of the present application is to describe a method for operating such a sealing device, which avoids the formation of damaged packages on restart after a machine shutdown.

[0011] The task is solved by a method with the features of the present application.

[0012] According to the application, the moistening unit has a moistening roller and a spraying device for a water-containing liquid, wherein the moistening unit can be switched between a first operating state and a second operating state. In the first operating state, the moistening roller acts on the cover film web at a roller moistening point. In the second operating state, the spraying device acts on a sprayed section of the cover film web in the input region between the roller moistening point and the sealing point.

[0013] According to the associated method according to the application, in the first operating state, the cover film web is moistened with the water-containing liquid in the input region at the roller moistening point by means of the moistening roller, is guided to the horizontally running base film web on the flat bed and is pressed and sealed perpendicularly to this base film web at the sealing point by means of the pressing device.

[0014] In the event of a machine standstill or after a machine standstill, the sealing device is in the second operating state. In the second operating state, the sprayed section of the cover film web in the input region between the roller moistening point and the sealing point is moistened with the water-containing liquid by means of the spraying device upon restart. The sealing device is then returned to the first operating state and the moistening is resumed by means of the moistening roller. The cover film web with its moistened sprayed section is guided to the horizontally running base film web on the flat bed and is pressed and sealed perpendicularly to this base film web along the sprayed section at the sealing point by means of the pressing device.

[0015] The basic idea is thus that, in the normal operating mode, the moistening roller, which is known per se from the drum machine and has proven itself, can now also be used in the flat bed and that a larger spacing between the roller moistening point and the sealing point is taken into account here. Reliable and uniform moistening of the cover film web above is thus ensured in the normal operating mode with simple means. The problem explained at the outset is solved by the use of the spraying device in the event of a temporary machine standstill and upon subsequent restart of the machine. Upon restart and shortly before the transition to the normal operating mode, the dry film region is at least approximately completely re-moistened and thus brought into a sealable state. This re-moistening takes place in the input region, in which the cover film web is fed from above to below to the pressing device. It is thus achieved that only the cover film, but not the drawn base film web with the already filled product, is moistened. The latter remains dry and is thus not damaged. The re-moistened region can now be covered and sealed as specified, resulting in a seal-tight packaging unit. Spillage of the filling and soiling of the machine are reliably avoided. The sealed unit can be operated as specified through all the following processing stations and is removed as a finished, sorted packaging unit. These packaging units sealed with the re-moistened cover film web can not meet the quality requirements specified and are thus sorted out as rejects. However, they at least do not prevent the orderly operation from being resumed undisturbed and thus the orderly operation can be carried out undisturbed.

[0016] For the purpose of resuming operation without disturbances, it can be sufficient to re-moisten only one section of the dried film section. In an advantageous further development of the application, however, the spraying section extends at least approximately from the roll moistening point to the sealing point. In this way, the dried film section is completely moistened again with moisture and can thus be completely covered by the lid, without omissions occurring during moistening and thus without defects in the sealing quality.

[0017] In a preferred embodiment, the spraying device has nozzles for outputting the water-containing liquid in beam fans and is designed to cover the complete spraying section by means of the beam fans. The re-moistening of the complete spraying section is achieved in only one pass by means of the beam fans. The shortness of the time required for this contributes to the uniformity of the achieved moistening, to the rapid resumption of normal operation and to the seamless transition of the re-moistened film section into the normally conventionally moistened cover film web.

[0018] It can be expedient for a plurality of such nozzles to be arranged side by side in a row and thus to cover the width of the cover film web. In an advantageous further development, however, the spraying device comprises a single nozzle mounted on a slide, which can be moved transversely to the cover film web by means of the slide. In combination with uniform water delivery, uniform moistening can thus be achieved with minimal expenditure.

[0019] Different construction forms can be considered for the design of the spraying device. For example, a nozzle can be provided which is accompanied by an intermittent piezoelectric delivery in order to produce a pulsed spraying grid. However, the spraying nozzle is preferably loadable with water-containing liquid by a pressure source and is designed for continuous output of the water-containing liquid. In this way, a uniform water film can be produced with components which are common on the market and cost-effective.

[0020] In a preferred embodiment, the input region is designed to guide the cover film web in the second operating state at least along a larger portion of the spraying section at an angle of 70° to 110°, in particular 80° to 100°, to the horizontal, i.e. at least approximately vertically. The plane of the cover film web in its spraying section is thus at least approximately orthogonal to the plane of the horizontally guided base film web. As a result, the spraying direction is on the one hand approximately perpendicular to the spraying section, which achieves a very effective moistening, and on the other hand approximately parallel to the base film web, so that this base film web is virtually not subjected to unintended moistening

[0021] In an advantageous extended design, the clamping device is positioned at the sealing location in the first operating state and moved away from the sealing location in the second operating state. Here, the sealing device has a stretching device that acts on the cover film web in the spraying section during the second operating state. After the clamping device is removed, the stretching device allows the cover film web to be fully inserted into an upright position from the sealing location and held there in a stretched, flat state. This allows for precise rewetting until it adheres tightly to the sealing location without obstructing the underlying base film web. As a result, the sealing process can continue seamlessly.

[0022] In the second operating state, the humidifying roller is preferably lifted from the cover film web. This facilitates rehumidification up to near the humidification area of ​​the roller without obstructing it. After the humidifying roller re-attaches, a seamlessly and continuously humidified film surface is created. Attached Figure Description

[0023] The embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.

[0024] Figure 1 The sealing device according to the invention is shown in a side view during routine operation in a flatbed packaging machine with a humidifying roller for humidifying the web of covering film to be sealed.

[0025] Figure 2 The diagram shows the buttons after the machine has stopped and when the machine with the spraying device is ready to be restarted to re-wet the covering film web. Figure 1 The arrangement; and

[0026] Figure 3 The front view shows the button. Figure 2 The spraying device has a separate nozzle mounted on a slider that can move laterally. Detailed Implementation

[0027] Figure 1 The side view shows a cut section of a flatbed packaging machine for a packaging unit consisting of a drawn base film web 1 and a cover film web 2 sealed onto the base film web 1. The cover film web 2, and here the base film web 1, are composed at least of a water-soluble film, preferably PVOH (polyvinyl alcohol). The packaging unit is filled with detergent, cleaning agent, or the like.

[0028] The packaging machine has multiple processing workstations, but... Figure 1 For simplicity, only the area of ​​the sealing workstation with the sealing device according to the invention is shown in part. Prior to this are the drawing and filling workstations (not shown). Following the sealing device are the sorting and unloading workstations.

[0029] The multiple gauge plates 18, each with a plurality of shaped, not shown here, female molds, are conveyed linearly, horizontally and here also continuously through the respective processing stations and then loop back in the manner of a conveyor belt corresponding to the arrow 17. But an intermittent operation can also be suitable. In the drawing station, the base film web 1, which is flatly and horizontally arranged on the gauge plate 18, is heated to a plastic-deformable temperature and drawn by means of vacuum into the female molds of the gauge plate 18 and held there. Thereby, drawn cavities or mold cavities are produced in the base film web 1, which are filled in the following filling station with a filling material, i.e. with a detergent or a cleaning agent. On the thus prepared base film web, the cover film web 2 is applied and sealed to the base film web in the sealing station shown here by means of a sealing device according to the invention, with the result that a multiple web with the respective filled, sealingly closed film cavities is generated. These webs are punched out as packaging units in the sorting station already mentioned at the beginning and finally removed from the gauge plate 18 in the removal station for further use.

[0030] According to Figure 1 , the sealing device according to the invention has a moistening unit 4 for moistening the cover film web 2 with an aqueous liquid 3. It is provided here to have water with added surfactant as the aqueous liquid. But tap water can also be suitable. The moistening unit 4 comprises a moistening roller 8 and a spraying device 10, both of which are designed and intended for applying the aqueous liquid 3 to the cover film web 2. The sealing device according to the invention furthermore has a pressing device 5, which is designed and intended for pressing and sealing the cover film web 2 moistened by means of the moistening unit 4 to the base film web 1 perpendicularly at the sealing point 6. The pressing device 5 is designed as a laminating roller in the shown embodiment, which is linearly arranged to the gauge plate with a perpendicular pressure line in the case of an intermediate sandwich of the base film web and the cover film web 1, 2 at the sealing point 6. But a pressure punch or the like can also be used. Under the action of the pressure, the previously moistened and thus partially dissolved on its surface cover film web 2 is materially sealed to the base film web 1. It can finally also be seen that the sealing device has an input area 7, in which the cover film web 2 is conveyed from above to below to the pressing device 5, that is to say essentially transversely to the conveying direction 17 of the gauge plate 18 with the base film web 1. The moistening unit 4 acts on the cover film web 2 in this input area 7. In other words, the moistening of the cover film web 2 is completed in the input area 7, i.e. where the cover film web 2 moves from above to below. The stretching device 16 keeps the cover film web 2 in a position in the input area 7 and under longitudinal stress in the stretched state.

[0031] Figure 1A sealing device according to the application is shown in a first operating state in which the routine continuous sealing process is carried out. Here, the spraying device 10 is passive. Rather, the moistening is carried out exclusively by means of the moistening roller 8, which is designed as a felt roller and which, in the input region 7, lies on the roller moistening site 9 on the surface of the cover film web 2. The roller moistening site 9 can be linear. In the shown embodiment, the cover film web 2 lies on the moistening roller 8 with a small winding angle, so that the roller moistening site 9 has the shape of a narrow, but flat strip. The moistening roller 8 projects from above into the tank 19, which is filled with liquid 3. There, the moistening roller absorbs the liquid 3 and outputs it to the cover film web 2 at the roller moistening site 9 over the entire width of the cover film web. For this purpose, it is sufficient for the moistening roller 8 to simply roll over the surface of the cover film web 2 without its own drive. However, the moistening roller 8 preferably has its own drive, by means of which it is rotated counter to the extraction direction of the cover film web 2.

[0032] This moistened cover film web 2 is now further continuously extracted in the routine operation, is delivered to the pressing device 5 and is lidded as described above. However, temporary operating interruptions or machine downtimes can occur, at the end of which, after the restart of the packaging machine, the material present in the packaging machine should continue to be processed to packaging units without disturbances. Such interruptions, in which the continuous movement and the continued processing are missing, lead to the undesirable drying of the cover film web 2, which has already been moistened, but not yet lidded and is in a stationary state, in the region between the roller moistening site 9 and the sealing site 6.

[0033] In order to restore the operation and in order to re-moisten the dried film section as required, according to the operating method according to the application, the sealing device is switched to Figure 2 the second operating state, which is shown in Fig. 2. The switching can be done during the machine downtime or directly after this at the restart of the packaging machine. In any case, the sealing device is thus in a state in which, at the restart of the machine, the moistening roller is first passive and in which, instead, the already mentioned spraying device is used. Here, the spraying device 10 acts on the sprayed section 11 of the cover film web 2, which is between the roller moistening site 9 and the sealing site 6, in the input region 7. In other words, in the second operating state, the sprayed section 11 of the cover film web 2, which is between the roller moistening site 9 and the sealing site 6 in the input region 7 and which has already been moistened once but is now dried, is re-moistened with the aqueous liquid 3 by means of the spraying device 10.

[0034] By Figure 1 and 2The overview shows further details: the clamping device 5 is positioned at the sealing part 6 in the first operating state and is moved away from the sealing part in the second state. Therefore, in the second operating state ( Figure 2 ), the laminating rollers from the first operating state ( Figure 1 The operating position of the sealing part 6 is moved or pivoted to the upper right, thereby releasing the sealing part 6 upward instead of covering it in the second operating state. The stretching device 16 now holds the covering film web 2 in place and under longitudinal stress throughout the input area 7 and particularly in the spraying section 11, which will be described in more detail later. "Holding it in place" here means that, in the second operating state, the covering film web 2 is at least along the larger portion of the spraying section 11 at an angle of 70° to 110° and preferably 80° to 100° relative to the horizontal line. Ground guidance. In the illustrated embodiment, the extension device 16 is relative to the press Figure 1 The operating position moves to the right until the stretching device is positioned exactly above the sealing part 6, thereby placing the covering film 2 at an angle of approximately 90° relative to the horizontal line in the input area 7, especially in the spraying section 11. The repositioning of the clamping device 5 and the stretching device 16 further facilitates the repositioning of the cover film web 2 to the right in the input area 7, i.e., away from the humidifying roller 8, resulting in the cover film web 2 and the humidifying roller 8 lifting each other. Additionally, the humidifying roller is also pressing... Figure 2 Compared to the second running state Figure 1 In its first daily operation, the water tank 19 is simply raised so that the section of the covering film 2 is exposed horizontally toward the spraying device 10 between the previous roller humidification section 9 and the sealing section 6.

[0035] In this state, when the packaging machine restarts, the previously dried sections of the film web 2 are re-wetted with an aqueous liquid 3, which is performed by means of the spraying device 10. The area of ​​the film web 2 covered by the spraying device 10 between the roller humidification section 9 and the sealing section 6 is referred to here as the spraying section 11. It may be sufficient to wet the spraying section 11, which may not completely cover the section between the roller humidification section 9 and the sealing section 6. However, by means of the measures described above and the corresponding construction scheme of the spraying device 10, the spraying section 11 is adjusted according to... Figure 2 The diagram at least approximates, and in this case even extends entirely from the roller humidification section 9 to the sealing section 6.

[0036] For this purpose, the spraying device 10 has a nozzle 13 for outputting water-containing liquid 3 in a beam fan shape 12. The opening angle of the beam fan shape 12 and the distance between the nozzle 13 and the covering film web 2 are coordinated so that the spraying section 11 is completely covered in the longitudinal direction of the second film web 2 by means of the beam fan shape 12.

[0037] Multiple such nozzles can be arranged side by side. This opens up the possibility of humidifying the spray section 11 with a single spray along the entire width of the covering film web 2 using overlapping, tapered beam fans 12. However, in the preferred embodiment shown, only a single nozzle 13 is provided, which, when pressed... Figure 3 The front view is shown in detail. The nozzle 13 and the associated adjusting unit 22 are thus mounted together on the slider 14, which allows for transverse movement of the covering film web 2 along the guide rail 20, corresponding to the double arrow 21. The adjusting unit 22 includes a needle valve (not shown) and is responsible for setting and maintaining a specific flow rate of the aqueous liquid 3 through the nozzle 13. Furthermore, a pressure source 15 for the aqueous liquid 3, shown only schematically here, is provided, from which the aqueous liquid 3 is loaded and supplied to the nozzle 13 through the adjusting unit 22. The pressure source 15 can be a pump and is currently a pressure tank. However, other suitable pressure sources 15 may also be selected. The structural unit consisting of the liquid pump 15 and the nozzle 13 is designed, particularly in conjunction with the adjusting unit 22, for continuous liquid output and therefore for continuously generating a beam fan 12 as an upright, flat beam. The beam fan 12 thus travels continuously and moves along the entire width of the covering film strip 2 in continuous motion, so that the spray section 11 is wetted with the water-containing liquid 3 over the entire width.

[0038] Now that the dried spray section 11 has been rehumidified, the sealing device returns to its original position. Figure 1 In the first operating state, the spraying device 10 stops operating, and the wetting of the cover film web 2 is resumed by means of the wetting roller 8. Also considered a restart of the packaging machine is the process of guiding the cover film web 2, with its wetted spraying section 11, to the horizontally running base film web 1 on the flatbed, and then pressing and sealing it vertically along the spraying section 11 at the sealing point 6 by means of the pressing device 5, in the manner described above. However, once the spraying section 11 is completely covered and the cover film web 2, wetted by means of the wetting roller 8, reaches the sealing point 6 in the usual manner, then routine sealing operation resumes, and the restart of the packaging machine can be considered complete.

[0039] As with the normally humidified and sealed packaging units, the packaging units sealed by means of the spraying section 8 during the restart are sealed. Depending on the desired appearance, these packaging units can be used as the finished product or sorted out. In any case, the achieved sealing is sufficient to enable an orderly operation of the packaging machine.

Claims

1. Sealing apparatus for sealing packages on a flat bed machine, wherein, The packaging is formed from a substrate film web (1) and a cover film web (2), wherein the cover film web (2) is formed at least from a water-soluble film, wherein the sealing device comprises a liquid input for an aqueous liquid (3), at least one moistening unit (4) for moistening the cover film web (2) with the aqueous liquid (3) and a pressing device (5) for pressing and sealing the cover film web (2) to the substrate film web (1) in a vertically compressed state with the liquid (3) at a sealing point (6), wherein the sealing device has an input region (7) in which the cover film web (2) is conveyed from above to below to the pressing device (5) and wherein the moistening unit (4) acts on the cover film web (2) in the input region (7), characterized in that the moistening unit (4) has a moistening roller (8) and a spraying device (10) for the aqueous liquid (3), wherein the moistening unit (4) is switchable between a first operating state and a second operating state, wherein in the first operating state the moistening roller (8) acts on the cover film web (2) at a roller moistening point (9) and wherein in the second operating state the spraying device (10) acts on a spraying section (11) of the cover film web (2) in the input region (7) between the roller moistening point (9) and the sealing point (6).

2. The sealing device of claim 1, wherein The spraying section (11) extends at least from the roller moistening point (9) to the sealing point (6).

3. A sealing device according to claim 1 or 2, characterized in that The spraying device (10) has a nozzle (13) for outputting the aqueous liquid (3) in a beam fan (12) and is designed to cover the complete spraying section (11) with the beam fan (12).

4. The sealing device of claim 3, wherein The spraying device (10) comprises a separate nozzle (13) mounted on a slide (14), which can be moved transversely to the cover film web (2) by means of the slide (14).

5. The seal of claim 3, wherein The nozzle (13) can be loaded with the aqueous liquid (3) by a pressure source (15) and is designed to output the aqueous liquid (3) continuously.

6. The sealing device according to claim 1 or 2, characterized in that The input region (7) is designed to guide the cover film web (2) in the second operating state at an angle of 70° to 110° to the horizontal at least along a larger portion of the jet section (11). ) 7. The sealing device according to claim 1 or 2, characterized in that The pressing device (5) is positioned at the sealing point (6) in the first operating state and is positioned away from the sealing point in the second operating state, and the sealing device has a stretching device (16) which acts on the cover film web (2) in the spraying section (11) in the second operating state.

8. The sealing device according to claim 1 or 2, characterized in that In the second operating state, the moistening roller (8) is lifted from the cover film web (2).

9. The sealing device of claim 6, wherein The cover film web (2) is guided at an angle of 80° to 100° to the horizontal at least along a larger portion of the jetting section (11) ).

10. Method for operating a sealing device according to any one of claims 1 to 9, comprising the following method steps: - in the first operating state, moistening the cover film web (2) with the aqueous liquid (3) in the input region (7) at the roller moistening point (9) by means of the moistening roller (8), guiding it to the horizontally running substrate film web (1) on the flat bed and pressing and sealing it to the substrate film web at the sealing point (6) by means of the pressing device (5); - bringing the sealing device into the second operating state at or after a machine standstill. - upon restart, in the second operating state, wetting the spray section (11) of the cover film web (2) in the input region (7) between the roll moistening point (9) and the sealing point (6) with the water-containing liquid (3) by means of the spraying device (10); - immediately after returning the sealing device again into the first operating state and resuming the moistening by means of the moistening roll (8); - guiding the cover film web (2) with its wetted spray section (11) to the horizontally running base film web (1) on the flat bed and pressing and sealing it perpendicularly to the spray section (11) at the sealing point (6) by means of the pressing device (5).

Images