EP4101774A1 - Sealing device and method for sealing packagings - Google Patents

Abstract

The invention relates to a device and a method for sealing packaging on a flatbed machine, the packaging being formed from a base film web (1) and a water-soluble cover film web (2). The sealing device comprises a liquid supply for an aqueous liquid (3), at least one moistening unit (4) and a pressing device (5) for vertically pressing and sealing the web of cover film (2) to the web of base film (1). The moistening unit (4) has a moistening roller (8) and a spray device (10) for the aqueous liquid (3), the moistening unit (4) being switchable between a first operating state and a second operating state. In the first operating state, the moistening roller (8) acts on the web of cover film (2) at a roller moistening point (9). During or after a machine standstill, the sealing device is switched to a second operating state, with the spraying device (10) in the feed area (7) acting on a spraying section (11) of the web of cover film (2) located between the roller moistening point (9) and the sealing point (6). .

Description

The invention relates to a sealing device for sealing packages according to the preamble of claim 1 and a method for operating such a sealing device.

Detergents and dishwashing detergents for domestic use are increasingly being packaged in the form of powders or liquids in water-soluble packaging. The packaging consists of water-soluble film and contains a unit dose of the detergent or dishwashing liquid. The filled and sealed packaging unit is placed in the washing machine or dishwasher. On contact with water, the foil packaging dissolves and releases the contents in the intended amount.

In the production of such a packaging unit, a base film web and a cover film web are used, which are formed from water-soluble films. Usually, the base film is deep-drawn into appropriate matrices under the action of heat and vacuum. The molding process creates cavities in the base film that are filled with the product. A cover film is then sealed onto the base film. The contents in the molds are enclosed by the sealing of both foils. Finally, the sealed packaging units are separated from the coherent film webs so that they can be used individually by the user.

In addition to the heat sealing process known per se for films, water sealing can also be considered for sealing such packaging. On drum machines, in which the matrices are arranged on revolving drums, dampening units with a felt roller are used, by means of which water is applied to the cover film. The moistened felt roll rolls on the water-soluble foil web, causing its surface to be dissolved. The cover film with the partially dissolved surface is then pressed onto the prepared base film by means of a pressure roller, the dissolving of the film surface causing a seal. Arrangement and method of this type are, for example, from GB 2 475 538 A known. Because of the cylindrical shape of the drum, filling and sealing must occur in quick succession and in close proximity to the top of the drum so that the product remains in the deep-drawn cavity and does not leak out. This limits the capacity of such a machine type.

As an alternative to the drum machines mentioned, flatbed machines are used in which format plates with molded matrices are moved around in a manner comparable to a conveyor belt and perform a horizontal movement during the process steps relevant to deep-drawing, filling and sealing. Compared to drum machines, larger output quantities per unit of time are possible because one or more format plates, each with several matrices, can run through a process step at the same time. However, the latter requires that the individual process stations along the horizontal movement path are locally relatively far apart from one another.

In the event of a production interruption, i.e. a temporary machine standstill, this distance has a negative impact. There is a comparatively long section of the moistened cover film web between the moistening device and the sealing point, which is not yet sealed and when standstill begins to dry. When restarting after the machine has stopped, this film section no longer has the desired degree of moisture and can no longer be easily sealed with the required quality. Improperly sealed products are created, from which the filling material escapes and contaminates the packaging machine, which can lead to renewed machine downtime. In addition, the improperly sealed products in the machine outlet cannot be properly discharged.

It is not possible to re-moisten the critical, partially dried film section with the moistening roller. As an alternative, the EP 3 323 740 B1 a device and a method in which an electromechanical spraying system with a row of outlet nozzles for contactless spraying of a water-containing liquid onto the web of cover foil is used in a manner comparable to an inkjet printer. In normal operation, the electromechanical spray system moistens the web of cover film on the circumference of the pressure roller, i.e. just before the sealing point. Nevertheless, a certain film section remains between the moistening point and the sealing point, which can dry out in the event of a machine standstill and can lead to the consequences described above when the machine is restarted. To counter this, describes the EP 3 323 740 B1 nor the possibility of a swiveling design of the electromechanical spray system, which is to be used when restarting. However, pivoting for remoistening means that the row of spray nozzles must be swiveled and directed from the original moistening point to the dried lower area of the pressure roller, as a result of which not only the cover film web, but also the thermoformed base film web with the product already filled in, is in an undesirable position way is also moistened. Elaborate countermeasures are required. The problem of restarting is in the EP 3 323 740 B1 not resolved satisfactorily.

The invention is based on the object of further developing the generic sealing device in such a way that improved restart behavior is achieved.

This object is achieved by a sealing device having the features of claim 1.

The invention is also based on the object of specifying a method for operating such a sealing device, which avoids the formation of defective packaging when restarting after a machine standstill.

This object is achieved by a method having the features of claim 9.

According to the invention, it is provided that the moistening unit has a moistening roller and a spray device for the water-containing liquid, the moistening unit being switchable between a first operating state and a second operating state. In the first operating state, the moistening roller acts on the web of cover film at a roller moistening point. In the second operating state, the spraying device acts in the feed area on a spraying section of the web of cover film located between the roller moistening point and the sealing point.

According to the associated method according to the invention, in the first operating state, the cover film web is wetted with the water-containing liquid by means of the moistening roller in the feed area at the roller moistening point, guided to the base film running horizontally on the flatbed machine and vertically pressed and sealed with it at the sealing point by means of the pressing device.

During or after a machine downtime, the sealing device is switched to a second operating state. When restarting, in the second operating state, the spray section of the web of cover film lying in the feed area between the roller moistening point and the sealing point is wetted with the water-containing liquid by means of the spray device. The sealing device is then switched back to the first operating state and wetting by means of the moistening roller is resumed. The cover film web is guided with its wetted spray section to the base film running horizontally on the flatbed machine and is pressed and sealed vertically with this at the sealing point by means of the pressing device along the spray section.

The basic idea is therefore to use the well-established dampening roller, which is known and proven from drum machines, in a flatbed machine in normal operation and to accept the comparatively large distance between the roller dampening point and the sealing point. This ensures reliable and uniform moistening of the upper web of cover foil in normal operation using simple means. The problems described above with temporary machine downtime and the subsequent restart of the machine are solved by using the spray device. When starting up again and shortly before the transition to normal operation, the dried film area is at least approximately completely moistened again and thus brought into a state capable of being sealed. This renewed moistening takes place in the feed area, in which the web of cover film is fed from top to bottom to the pressing device. This ensures that only the cover film is moistened with the product that has already been filled in, but not the thermoformed base film web. The latter remains dry and is therefore not damaged. The remoistened area can now be properly sealed to form tightly sealed packaging units. Leakage of the filling and contamination of the machine are reliably avoided. The sealed units can pass through all subsequent processing stations properly and as finished, individual packaging units can be removed. It is possible that these packaging units sealed with the remoistened web of cover film do not meet the quality requirements, so that they have to be sorted out as bad parts. But at least they don't hinder the resumed proper operation, so that the latter can take place without problems.

For a trouble-free resumption of operation, it may be sufficient under certain circumstances to moisten only a partial area of the dried film section again. In an advantageous development of the invention, however, the spray section extends at least approximately from the roller moistening point to the sealing point. This ensures that the partially dried film section is completely wetted again with moisture and consequently can be properly sealed on completely without gaps in the moistening and thus gaps in the sealing quality occurring.

In a preferred embodiment, the spray device has a spray nozzle for dispensing the water-containing liquid in a jet fan and is designed to cover the entire spray section by means of the jet fan. The width of the spray fan ensures that the entire spray section is remoistened in just one single operation. The shortness of the time required for this contributes to the homogeneity of the moisture condition reached, to a rapid resumption of normal operation and to a seamless transition from the remoistened film section to the usually moistened cover film web.

It can be expedient to arrange several such nozzles next to one another in a row and thus to cover the width of the web of cover film. In an advantageous further development, however, the spray device comprises a single spray nozzle mounted on a carriage, which can be moved transversely to the web of cover film by means of the carriage is. In connection with an even water supply, an even wetting can be achieved with minimal effort.

Various designs can be considered for the design of the spray device. For example, a nozzle with intermittent piezo-delivery can be provided in order to generate a pulsating spray pattern. However, the spray nozzle can preferably be acted upon by a pressure source with the water-containing liquid and is designed for the continuous delivery of the water-containing liquid. In this way, a homogeneous water film can be generated with commercially available and inexpensive assemblies.

In a preferred embodiment, the feed area is designed so that, in the second operating state, the cover film web is fed at least along the larger part of the spray section at an angle of 70° to 110° and in particular at an angle of 80° to 100° to the horizontal, i.e. at least approximately vertically to lead. The plane of the web of cover film in its spraying section is therefore at least approximately orthogonal to the plane of the horizontally guided web of base film. As a result, the spray direction is on the one hand approximately perpendicular to the spray section, which ensures effective wetting, and on the other hand approximately parallel to the base film, as a result of which it experiences practically no unintentional wetting.

In an advantageous further development, the pressing device is positioned at the sealing point in the first operating state and is remote therefrom in the second operating state. In this case, the sealing device has a stretching device which, in the second operating state, acts on the covering film web in the spraying section. After the pressing device has been removed, it is possible by means of the stretching device to bring the covering film web completely into the upright position, starting from the sealing point, and to keep it stretched there in a flat state. This enables an exact Remoistening right up to the sealing point without affecting the lower base film web. The sealing process can then be continued seamlessly.

In the second operating state, the moistening roller is preferably lifted off the web of cover film. This contributes to the fact that the remoistening can be carried out directly up to the roller dampening point, without the dampening roller being in the way. After reapplying the moistening roller, a seamless, continuous moistened film surface is created.

Fig. 1

in einer seitlichen Ansicht eine erfindungsgemäße Versiegelungsvorrichtung beim gewöhnlichen Betrieb in einer Flachbett-Verpackungsmaschine mit einer Befeuchtungswalze zur Befeuchtung der aufzusiegelnden Deckfolienbahn,

Fig. 2

die Anordnung nach Fig. 1 nach einem Maschinenstillstand und bei der Vorbereitung des Wiederanfahrens der Maschine mit einer Sprüheinrichtung zur erneuten Befeuchtung der Deckfolienbahn, und

Fig. 3

in einer Stirnansicht die Sprüheinrichtung nach Fig. 2 mit einer einzelnen, auf einem quer verfahrbaren Schlitten montierten Sprühdüse.

An embodiment of the invention is described in more detail below with reference to the drawing. Show it:

1

in a side view, a sealing device according to the invention during normal operation in a flatbed packaging machine with a moistening roller for moistening the web of cover film to be sealed,

2

according to the arrangement 1 after a machine downtime and when preparing to restart the machine with a spray device for rewetting the web of cover foil, and

3

the spray device in a front view 2 with a single spray nozzle mounted on a traversing carriage.

1 shows a side view of a section of a flatbed packaging machine for producing packaging units from a deep-drawn base film web 1 and a cover film web 2 sealed onto the base film web 1. At least the cover film web 2, here also the base film web 1 consist of a water-soluble film, for which PVOH (polyvinyl alcohol) is preferably selected. The packaging units are filled with detergent, detergent or the like.

The packaging machine has several processing stations, but is in 1 for the sake of simplicity, only excerpts are shown in the area of their sealing station with the sealing device according to the invention. This is preceded by a deep-drawing station (not shown) and a filling station. The sealing device shown is followed by a separating station and a removal station.

Several format plates 18, each with several moulded-in matrices, not shown here, are conveyed in a straight line, horizontally and here also continuously through the individual processing stations according to an arrow 17 in the manner of a conveyor belt and then recirculated. However, intermittent operation can also be expedient. In the deep-drawing station, the base film web 1 lying flat and horizontal on the format plates 18 is heated to a temperature of plastic deformability and deep-drawn into the matrices of the format plates 18 by means of a vacuum and held there. This results in deep-drawn troughs or cavities in the base film web 1, which are filled with the filling material, ie with the detergent or detergent, in the subsequent filling station. A cover film web 2 is then applied to the base film web prepared in this way in the sealing station shown here using the sealing device according to the invention and sealed, resulting in a multi-layer web with individually filled, tightly sealed film cavities. These are cut out as packaging units in the separating station already mentioned at the outset and finally removed from the format plates 18 in the removal station for further use.

According to 1 the sealing device according to the invention has a moistening unit 4 for wetting the web of cover film 2 with the water-containing liquid 3 . The aqueous liquid here is water with added Surfactants provided. However, tap water can also be useful. The moistening unit 4 comprises a moistening roller 8 and a spray device 10, both of which are designed and provided for applying the water-containing liquid 3 to the web of cover film 2. The sealing device according to the invention also has a pressing device 5 which is designed and provided for the vertical pressing and sealing of the cover film web 2 moistened by means of the moistening unit 4 with the base film web 1 at a sealing point 6 . The pressing device 5 is designed in the embodiment shown as a laminating roller, which rests at the sealing point 6 in a line on the format plates with the interposition of the package of base and cover film web 1, 2 with vertical pressure. However, pressure stamps or the like can also be used. Under the action of said pressure, the cover film web 2, which has been moistened beforehand and thus partially dissolved on its surface, is sealed onto the base film web 1 in a cohesive manner. Finally, it can also be seen that the sealing device has a feed area 7 in which the cover film web 2 is fed from top to bottom to the pressing device 5, i.e. essentially transversely to the conveying direction 17 of the format plates 18 with the base film web 1. The moistening unit 4 acts on the web of cover film 2 in this feed area 7 . In other words, the web of cover film 2 is moistened in the feed area 7, ie where the web of cover film 2 is moved from top to bottom. A stretching device 16 holds the cover film web 2 in position within the feed area 7 and in the stretched state under longitudinal tension.

1 shows the sealing device according to the invention in a first operating state, in which a normal, continuous sealing process is carried out. Here, the spray device 10 is passive. Rather, the moistening is carried out solely by means of the moistening roller 8 , which is designed here as a felt roller and rests on the surface of the web of cover film 2 in the feed area 7 at a roller moistening point 9 . The roller dampening point 9 can be in the form of a line. In the exemplary embodiment shown, the web of cover film 2 lies above a small angle of wrap on the moistening roller 8, so that the roller moistening point 9 has the shape of a narrow but flat strip. The dampening roller 8 partially protrudes from above into a water bowl 19 filled with the liquid 3 . There it absorbs the liquid 3 and releases it at the roller moistening point 9 onto the web of cover film 2 over its entire width. To this end, it may be sufficient for the moistening roller 8 to simply roll on the surface of the web of cover film 2 without its own drive. However, the moistening roller 8 preferably has its own drive, by means of which it rotates in the opposite direction to the direction in which the web of cover film 2 is pulled off.

The web of cover film 2 moistened in this way is then continuously withdrawn in normal operation, fed to the pressing device 5 and sealed on as described above. However, there may be temporary interruptions to operations or machine downtimes, at the end of which, after the packaging machine has been restarted, the materials present in it are to be processed further and smoothly into packaging units. Such interruptions, in which there is no continuous movement and further processing, lead to undesired drying of the cover film webs 2, which have already been moistened but not yet sealed and are at a standstill, in the area between the roller moistening point 9 and the sealing point 6.

According to the operating method according to the invention, for the resumption of operation and for a necessary remoistening of the partially dried film section, the sealing device is switched to a second operating state, which 2 is shown. The changeover can take place while the machine is at a standstill or immediately afterwards when the packaging machine is restarted. In any case, the sealing device is thus placed in a state in which the moistening roller is initially passive when the machine is started up again, and in which the already mentioned spraying device is used instead. Here, the spray device 10 acts in the supply area 7 on a between the roller moistening point 9 and the sealing point 6 lying spray section 11 of the cover sheet web 2 a. In other words, in the second operating state, the spray section 11 of the web of cover film 2 in the feed area 7 between the roller moistening point 9 and the sealing point 6, which was previously wetted and has now dried on, is wetted again with the water-containing liquid 3 by means of the spraying device 10.

From the synopsis of Figures 1 and 2 further details can be seen: In the first operating state, the pressing device 5 is positioned at the sealing point 6, in the second operating state it is removed therefrom. For this purpose, in the second operating state ( 2 ) the laminating roller starting from the operating position of the first operating state ( 1 ) moved or pivoted to the top right, whereby the sealing point 6 is no longer covered in the second operating state, but is released upwards. The stretching device 16 now keeps the web of cover film 2 in position and under longitudinal tension in the entire feed area 7, and in particular in a spraying section 11, which will be described in more detail below. "Hold in position" means here that in the second operating state the web of cover film 2 is guided at least along the larger part of the spray section 11 at an angle a of 70° to 110° and preferably of 80° to 100° to the horizontal. In the embodiment shown, the stretching device 16 is towards the operating position 1 move to the right until it is positioned exactly above the sealing point 6 and thereby guides and holds the web of cover film 2 in the feed area 7, specifically in the spray section 11, at an angle (a) of approximately 90° to the horizontal. The repositioning of the pressing device 5 and the stretching device 16 also causes a repositioning of the cover film web 2 in the feed area 7 to the right, i.e. away from the dampening roller 8, as a result of which the cover film web 2 and the dampening roller 8 are lifted from one another. In addition, the dampening roller is still in the second operating state 2 compared to the first, normal operating state 1 including their water bowl 19 raised to the extent that the section of Cover sheet web 2 is exposed between the previous roller moistening point 9 and the sealing point 6 in the horizontal direction towards the spray device 10 .

In this state, when the packaging machine is started up again, the previously dried section of the web of cover film 2 is wetted again with the water-containing liquid 3 , which is carried out by means of the spray device 10 . The area of the web of cover film 2 reached by the spray device 10 between the roller moistening point 9 and the sealing point 6 is referred to here as the spray section 11 . Under certain circumstances, it may be sufficient to wet a spray section 11 that does not completely cover the distance between the roller moistening point 9 and the sealing point 6 . Due to the measures described above and a corresponding design of the spray device 10, however, the spray section 11 extends according to the illustration 2 at least approximately, here even completely from the roller moistening point 9 to the sealing point 6.

For this purpose, the spray device 10 has a spray nozzle 13 for dispensing the water-containing liquid 3 in a jet fan 12 . The opening angle of the jet fan 12 and the distance between the spray nozzle 13 and the web of cover film 2 are matched to one another such that the spray section 11 is completely covered by the jet fan 12 in relation to the longitudinal direction of the second film web 2 .

Several such spray nozzles can be arranged side by side. This would open up the possibility of moistening the spray section 11 along the entire width of the web of cover film 2 by means of overlapping, conical jet fans 12 with a single spray blast. In the preferred embodiment shown, however, only a single spray nozzle 13 is provided, which is shown in the end view according to FIG 3 shown in additional detail. Accordingly, the spray nozzle 13 is mounted together with an associated control unit 22 on a carriage 14 and by means of this carriage 14 on a guide rail 20 according to a double arrow 21 transverse to In the longitudinal direction of the web of cover film 2, it can be moved. The control unit 22 includes a needle valve, not shown, and is responsible for setting and maintaining a specific flow rate of the water-containing liquid 3 through the spray nozzle 13 . In addition, a pressure source 15 , indicated only schematically here, is also provided for the water-containing liquid 3 , from which the spray nozzle 13 is acted upon and fed with the water-containing liquid 3 through the control unit 22 . The pressure source 15 can be a pump and in the present case is a pressure tank. However, other suitable pressure sources 15 can also be selected. The assembly of the liquid pump 15 and spray nozzle 13 is designed, in particular with the cooperation of the control unit 22, for a continuous delivery of liquid and thus for the continuous generation of the jet fan 12 as an upright flat jet. The jet fan 12 is thus moved continuously and in a continuous movement along the entire width of the web of cover film 2, with the result that the spray section 11 is wetted with the water-containing liquid 3 over the entire width.

Now that the dried spray section 11 has been moistened again, the sealing device returns to its first operating state 1 offset, the spray device 10 taken out of operation, and the wetting of the web of cover film 2 by means of the moistening roller 8 resumed. To restart the packaging machine, the cover film web 2 with its wetted spray section 11 must be guided to the base film 1 running horizontally on the flatbed machine and pressed vertically with it at the sealing point 6 by means of the pressing device 5 along the spray section 11 in the manner described above and sealed . However, as soon as the spray section 11 is completely sealed and the web of cover film 2 moistened in the usual way by means of the moistening roller 8 reaches the sealing point 6, normal sealing operation resumes and the restarting of the packaging machine can be regarded as complete.

Just like the regularly moistened and sealed packaging units, the packaging units sealed by means of the spray section 8 during the restart are tight. Depending on the requirement profile, they can be used as a regular product or sorted out. In any case, the tightness achieved is sufficient for proper operation of the packaging machine.

Claims (9)

Sealing device for sealing packaging on a flatbed machine, the packaging being formed from a base film web (1) and a cover film web (2), at least the cover film web (2) being formed from a water-soluble film, the sealing device having a liquid supply for an aqueous liquid (3), at least one moistening unit (4) for wetting the cover film web (2) with the aqueous liquid (3) and a pressing device (5) for vertical pressing and sealing of the cover film web (2) with the base film web (1) at a sealing point ( 6) in the wetted state with the liquid (3), the sealing device having a feed area (7) in which the web of cover film (2) is fed to the pressing device (5) from top to bottom, and the moistening unit (4) in feed area (7) acts on the covering foil web (2),
characterized in that the moistening unit (4) has a moistening roller (8) and a spray device (10) for the water-containing liquid (3), the moistening unit (4) being switchable between a first operating state and a second operating state, with 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) in the feed area (7) acts on a spraying section between the roller moistening point (9) and the sealing point (6). (11) acts on the web of cover film (2). Sealing device according to claim 1,
characterized in that the spray section (11) extends at least approximately from the roller moistening point (9) to the sealing point (6). Sealing device according to claim 1 or 2,
characterized in that the spray device (10) has a spray nozzle (13) for dispensing the water-containing liquid (3) in a jet fan (12) and is designed to cover the entire spray section (11) by means of the jet fan (12). Sealing device according to claim 3,
characterized in that the spray device (10) comprises a single spray nozzle (13) mounted on a carriage (14) which can be moved transversely to the web of cover film (2) by means of the carriage (14). Sealing device according to claim 3 or 4,
characterized in that the spray nozzle (13) can be acted upon by a pressure source (15) with the water-containing liquid (3) and is designed for the continuous delivery of the water-containing liquid (3). Sealing device according to one of claims 1 to 5,
characterized in that the feed area (7) is designed to feed the web of cover film (2) at least along the larger part of the spray section (11) in the second operating state at an angle (a) of 70° to 110° and in particular at an angle (a ) from 80° to 100° to the horizontal. Sealing device according to one of claims 1 to 6,
characterized in that the pressing device (5) in the first operating state at the sealing point (6) positioned in the second Operating state is removed therefrom, and in that the sealing device has a stretching device (16) acting on the covering film web (2) in the spraying section (11) in the second operating state. Sealing device according to one of claims 1 to 7,
characterized in that in the second operating state the moistening roller (8) is lifted off the web of cover film (2). Method for operating a sealing device according to one of Claims 1 to 8, comprising the following method steps: - In a first operating state, the covering foil web (2) is wetted with the water-containing liquid (3) at a roller moistening point (9) in the feed area (7) by means of the moistening roller (8), guided to the base foil (1) running horizontally on the flatbed machine and vertically pressed and sealed with this at a sealing point (6) by means of the pressing device (5); - During or after a machine standstill, the sealing device is switched to a second operating state; - When starting up again in the second operating state, a spray section (11) of the cover film web (2) lying in the feed area (7) between the roller moistening point (9) and the sealing point (6) is wetted with the water-containing liquid (3) by means of the spray device (10); - The sealing device is then switched back to the first operating state and the wetting by means of the moistening roller (8) is resumed; - The web of cover film (2) is guided with its wetted spraying section (11) to the base film (1) running horizontally on the flatbed machine and is pressed vertically with it at the sealing point (6) by means of the pressing device (5) along the spraying section (11) and sealed.

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