EP2722281B1 - Method for gas-tight packing of objects with film close to the objects that can be deep-drawn using a vacuum - Google Patents

Description

The invention relates to a method for the gas-tight packaging of articles with deep-drawable film applied to the articles, using a vacuum, wherein the article is placed in a dish and the deep-drawable film is connected to the shell for closing the shell.

Methods of the aforementioned genera are used to package items. These articles may be inorganic products, such as tools or stationery, which are held in suitable packaging for sale in markets. In particular, when a vacuum is used to deep-draw the film which is welded to the shell, the articles may be organic products, such as food. In particular, meat and sausage products are packed with this type of packaging in order to leave the smallest possible gas volume in the interior of the packaging.

Known methods are for example DE 102 37 933 A1 known.

In known methods, the procedure is such that an object is placed in a dish and then the thermoformable film is welded to the shell. After deep drawing, the film is cut to the size of the shell, this often involves cutting of foil and shell in one step, for. B. when slipping of the shell occurs. In a disadvantageous way, sharp shell edges can be formed. Another Disadvantage is that this subsequent cutting is made on the still heated for welding film. The film has a soft consistency in its heated state so that it can provide little resistance to a cutting knife. As a result, blurred cut edges, which lead to an unsightly creasing and discarding the cut edges of the film.

The invention is based on the object to provide a method with which it is possible to pack objects in handsome designed gas-tight packaging.

This object is achieved according to the invention in that a shell with at least one circumferential edge is used for forming the packaging, that the thermoformable film is applied gas-tight to the peripheral edge and then only the thermoformable film is cut to a size smaller than the peripheral edge.

Also in the method according to the invention, a shell is used with a peripheral edge. However, this circumferential edge is not damaged in a packaging of an object, so that this edge can be provided from the outset with a pleasing and handle-friendly fold or other design. The peripheral edge of the shell is protected according to the invention in that after the application of the thermoformable film on the peripheral edge only the thermoformable film is cut.

In the method according to the invention, the processing sequence thus follows the prior art. First, the film is applied, then it is cut to size. This has the advantage that the cutting of the film is carried out in a late processing step. Also, the peripheral edges of the shell are not cut, since the cutting of the film is done in a manner in the designated cutting tools do not come in contact with the shell. An edge design of the shell is thus preserved, sharp edges are not beneficial.

According to a first development of the method according to the invention it is provided that the thermoformable film is welded onto the peripheral edge. By welding, on the one hand, a firm and gas-tight connection between film and shell is produced.

According to a next development of the invention, it is provided that the thermoformable film is exposed to heat before welding. By heating the film on the one hand, a pre-stretching. On the other hand, the film is heated so that it is easily accessible to a subsequent deep-drawing process. It can be provided that the thermoformable sheet is applied before welding with a vacuum in a widening their areal extent. By this pre-stretching of the film is achieved that the thermoformable film can penetrate into tight projections and undercuts during the deep drawing operation. Since usually in a corresponding device several shells are sealed at the same time, the required for the sealing of a shell thermoformable sheet material is taken from a larger composite. During the preparation of the thermoformable film, this composite is still uncut so that material can flow accordingly. The cutting of the thermoformable film is then according to the invention only after its welding to a shell edge.

In order to carry out the deep drawing, a further development of the invention provides that a vacuum is arranged in the surrounding area of the shell. With the vacuum pressure ratios can be set, which lead to a deep drawing of the film when forming a pressure gradient. By thermoforming, the film adheres tightly to the object to be packaged, as well as to areas of the shell not covered by the object, by the so-called "skin" method.

For the further embodiment of the method according to the invention, it is also provided that an overpressure can be formed in the surrounding region of the thermoformable film on the side facing away from the shell. The side facing away from the shell of thermoformable film can be loaded with the formable on this page overpressure. As a result, the vacuum acting on the other side of the thermoformable film is assisted in order to achieve the closest possible contact of the thermoformable film with the object to be packaged. The closest possible investment obtains advantageous not only a fixation of the object, it ensures at z. As meat-containing objects also ensure that contained in the meat in particular liquid ingredients can not escape from this. Thus, marinades or even their own meat juice can be kept in the product so that it does not dry out and retain freshness despite the longer shelf life produced by the package. The overpressure can be built up abruptly in order to achieve a faster and tight application of the film.

A device suitable for the method has in addition to the support for at least one shell and in addition to the sealing tool for the thermoformable film at least one cutting device for the thermoformable film, which can be brought into an only the deep-drawable film intersecting altitude above a peripheral edge of the shell.

According to the method of the invention, the film is first applied to the shell and subsequently cut. This procedure no longer requires a separate cutting station for the film. It may be associated with the device, since the cutting of the film takes place immediately after the sealing or welding of the film.

The cutting device preferably comprises knife blades, with which a cutting of the thermoformable film is successfully carried out.

It can further be provided that the cutting device is spatially associated with the sealing tool. Due to this spatial assignment, a temporally short successive sealing and cutting can take place. The assignment of cutting device and sealing tool to each other is given spatially, structurally, both modules are independent of each other to allow a separate performing the operations sealing and cutting.

The cutting device can rotate the sealing tool. If the sealing tool is rectangular, for example, knife blades of the cutting device can circulate this sealing tool like a frame. After placing the sealing tool on the film is done with the frame-like knife blades cutting the same.

For structural design of the device, a development provides that the support for the shell and / or the sealing tool are guided vertically variable. Pad and sealing tool can thus be approximated and removed from each other. The approach is used to place the sealing tool on the thermoformable sheet when the cutting tool still maintains a distance from the peripheral edge of the tray.

A next development provides that the support has at least one supporting device for the peripheral edge of the shell. The shell can be introduced by means of the support in the support device for the peripheral edge. The peripheral edge is preferably placed on this support means so that it is ready for welding or sealing with the thermoformable film. The support device supports the peripheral edge and forms an abutment for the aufgelegende on the edge sealing tool.

According to a next development of the device is provided that a spacer plate is disposed between the shells and the thermoformable film, which can be placed on the support means for the peripheral edge, wherein the peripheral edge remains at least partially free. This inventively provided spacer plate supports the cutting of the thermoformable film after its welding or sealing on the peripheral edge of the shell. For this purpose, the spacer plate can be placed on the recorded in the support means peripheral edges of the shell. The spacer plate now forms with its surface above a level, which is located above the peripheral edge. On this level, the thermoformable film can be placed, with the spacer plate, the thermoformable sheet is guided against the sealing tool.

According to the invention, it is provided that a vacuum is applied to the thermoformable film prior to its welding in order to stretch it. With the spacer plate, the film is guided against the sealing tool and held when a vacuum is applied to the film with the sealing tool. The sealing tool preferably has an inwardly curved formation into which the thermoformable film can expand upon application of the vacuum. The peripheral edges of the shell are kept free by the spacer plate. The other areas of the shell can remain free to allow a large-scale investment of the sealing tool, so that in addition to the welding of the thermoformable film at the same time a heating of this film for a subsequent deep-drawing process. In the spacer plate is preferably arranged at least one can be brought into congruent position with the container breakthrough. This breakthrough then has dimensions corresponding to the sealing tool.

When using this spacer plate with the apertures, it is advantageous to assign the cutting device spatially to the sealing tool. When the sealing tool is brought to the deep-drawable film, the cutting device can be fed at the same time. The cutting device is preferably as the sealing tool through the breakthrough of the spacer plate feasible. The cutting tool is preferably uncoupled from the sealing tool and resiliently mounted. This decoupling makes it possible to bring the sealing tool closer to the shell first than the cutting tool. After this approach of the sealing tool, a seal between the film and shell can be done. For this purpose, the cutting tool is guided in a corresponding guide to the plane of the surface of the peripheral edge. The lying on the peripheral edge thermoformable film is cut, but the knife is not moved into the peripheral edge. The peripheral edge remains intact.

For a further embodiment of the device, it is preferably provided that at least one overpressure line and / or one vacuum line runs through the sealing tool. The sealing tool is disposed on the side of the thermoformable sheet, which is turned away from the shell. By passing through the sealing tool through pressure line, an overpressure medium, for. As air, are added to produce on this side of the film according to the method preferably provided overpressure. About the vacuum line of the procedure provided for negative pressure is generated.

A packaging produced by the method according to the invention is characterized in that the thermoformable film covering this edge in sections after being placed on at least one peripheral edge of the shell.

It is thus envisaged that the film applied to the peripheral edge does not completely cover this edge. The foil may in each case have a return to the outer edge of the peripheral edge, so that it does not come into contact with this edge. Rather, it may be welded to a portion of the peripheral edge which extends from the outer edge of the circumferential margin still has a gap. This creates a clean weld.

A peripheral edge of the shell is always the area of the shell surface, which surrounds at least one depression in the shell circumferentially. The shell may have a recess which is surrounded by a peripheral edge. It is also possible that a plurality of recesses are arranged in an overall packaging, for example in a plurality of composite yogurt cups. Each of these depressions may be associated with a separate thermoformable film, which is only connected to the peripheral edge surrounding this depression. Thus, there is no total covering of the various depressions with a film, but several films are provided. This package has between the individual wells areas that are not occupied by a film. Perforations may then preferably be applied in these areas in order to facilitate the separation of the individual packaging areas from one another. In this case, take-off tabs of the thermoformable sheet may also be laid from an outer package of the overall package to an inner area, for example, where the thermoformable sheets of multiple wells are approximated.

Fig. 1 bis 9:

Schnittansichten einer Vorrichtung zum gasdichten Verpacken von Gegenständen mit sich eng an die Gegenstände anlegen dem Folienmaterial in verschiedenen Bearbeitungssituationen während eines Verpackungsvorganges und

Fig. 7 a:

eine maßstäblich vergrößerte Darstellung einer Einzelheit in Fig. 7 und

Fig. 9 a:

eine maßstäblich vergrößerte Darstellung einer Einzelheit in Fig. 9.

An embodiment of an apparatus for carrying out the method according to the invention is shown in the drawing. Show it:

1 to 9:

Sectional views of a device for gas-tight packaging of objects with close to the objects create the film material in different processing situations during a packaging process and

Fig. 7 a:

a scale enlarged representation of a detail in Fig. 7 and

Fig. 9a:

a scale enlarged representation of a detail in Fig. 9 ,

The device in the figures has a lower tool 9 and an upper tool 1. The lower tool 9 comprises a support table 8 for two shells 6. Each of the shells 6 has a peripheral edge 10. The support tables 8 are mounted on a frame 11 which is height-adjustable.

In the upper tool 1, two sealing tools 2 are added. The upper tool 1 is guided altogether variable in height. The sealing tools 2 spatially associated cutting devices 3, which are formed as the sealing tools 2 rotating knife. The cutting devices 3 are received in knife holders 12.

FIG. 1 further shows a thermoformable film 4. This film 4 is before its sealing on the peripheral edges 10 of the shells 6 in one piece.

The device still has a spacer plate 5 between the thermoformable film 4 and the shells 6. This spacer plate 5 has openings 13, which correspond to the shells 6.

In the area of the lower tool 9 the support tables 8 is still assigned a support means. This support device is formed by the uppermost portions of the lower tool 9. In the area of this support means 9 depressions 14 are embedded in the surface of the lower tool, in which the peripheral edges 10 of the shells 6 can protrude.

FIG. 2 shows the state after bringing the thermoformable sheet 4 to the upper tool 1. This approach is carried out with the spacer plate 5, which Subsequently, the thermoformable sheet 4 presses against the upper tool 1 and holds. The bringing of the thermoformable film 4 is shown with arrows 20 a.

FIG. 3 shows that runs through the sealing tools 2, a vacuum line. Along the arrows 20 air is led out of the sealing tools 2. As a result, the thermoformable film 4 applies to the inner contours of the sealing tools 2. These are curved inwards so that dome-like sections result.

FIG. 4 shows the state after lifting the lower tool 9. The shells 6 are placed on the support means of the lower tool 9. Their peripheral edges 10 are supported by the lower tool 9.

The spacer plate 5 is placed on the lower tool 9. On the spacer plate 5 is the thermoformable film 4, the upper tool 1 with the sealing tools 2 and the cutting means 3 of the film 4 is approximated. In this case, the thermoformable film 4 is expanded into the sealing tools 2 and preheated. The cutting devices 3 keep a distance from the film 4.

FIG. 5 shows that air is sucked out of the surrounding area of the shells 6 via air ducts 15 (arrows 16). As a result, a vacuum is produced in the surrounding area of the shells 6.

In FIG. 6 the cutting devices 3 are not brought up to the peripheral edges 10 of the shells 6. With the sealing tools 2, the thermoformable film 4 is now welded onto the peripheral edges 10. At the same time there is a warming up of the film 4 for preparing the deep drawing. The placement of the sealing tools 2 on the peripheral edges 10 of the shells 6 is illustrated by arrows 17.

Fig. 7 and 7a then show the cutting of the thermoformable film 4 with the cutter 3. About the knife holder 12, the cutter 3 is defined on the peripheral edge 10 of the shell 6 is brought. In this case, a severing of the thermoformable sheet 4, while the peripheral edge 10 is not damaged. The trimming of the film 4 takes place before deep-drawing of this film 4.

In Fig. 8 via overpressure lines 18 guided through the upper tool 1 and the sealing tools 2, a supply of air which, in connection with the negative pressure prevailing in the region of the shells 6, ensures close contact of the heated, deep-drawable film 4 with the objects 7 located in the shells 6. The articles 7 may be, for example, meat products. In the area of the shells 6 while still a protective gas can be performed (arrow 19).

FIG. 9 shows the state of the device after demolding of the shells 6. Upper tool 1 and lower tool 9 are removed from each other again, the spacer plate 5 is lifted from the shells 6. Of the thermoformable film 4 remain cut remnants, which are disposed of. The shells 6 can be removed after this sealing process of the lower tool 9, this can then record new shells 6. The device can work in cycles, for example, with 6 cycles per minute.

The device can be a sealing device with which it is also possible to seal trays with films which are not thermoformed in the "skin" process. One and the same device can thus be used for mutually different types of packaging, in which the same standardized basic packaging, such as the shells 6, are used.

The cutting of the thermoformable film 4, the welding of this film 4 on the peripheral edges 10 and the deep drawing of the film 4 is preferably carried out in one and the same cycle to shorten the processing time.

The cutters 3 are not passed through the plane of the peripheral edges 10. FIG. 9 a shows that the deep-drawable film 4 is cut clean and that in the region of the peripheral edge 10, a region of this peripheral edge 10 remains free of the film 4. The cutting devices 3 do not cut off the peripheral edge 10.

The film 4 fits tightly against the walls of the container 6 and to objects 7 present in the recess of the container, as in FIG FIG. 9 shown.

Claims (5)

1. Method for gas-tight packing of objects with film close to the objects that can be deep-drawn using a vacuum, wherein the object is placed in a tray and for sealing the tray the film that can be deep-drawn is connected to the tray,
   characterised in that
   a tray (6) with at least one peripheral edge (10) is used for forming the packaging, in that the film (4) that can be deep-drawn is applied in a gas-tight manner onto the peripheral edge (10) and exclusively the film (4) that can be deep-drawn is then cut to a smaller size than the peripheral edge (10), wherein an overpressure is formed on the side remote from the tray (6) in the surrounding region of the film (4) that can be deep-drawn.
2. Method according to Claim 1, characterised in that the film (4) that can be deep-drawn is welded onto the peripheral edge (10).
3. Method according to Claim 1 or 2, characterised in that the film (4) that can be deep-drawn is subjected to the application of heat before being welded on.
4. Method according to one of the preceding claims, characterised in that the film (4) that can be deep-drawn is subjected to a vacuum before being welded on, in a manner widening the surface extent thereof.
5. Method according to one of the preceding claims, characterised in that a vacuum is arranged in the surrounding region of the tray (6).

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