DE3342171A1 - VACUUM FILM PACKAGING - Google Patents

Description

description

The invention relates to a vacuum film packaging method, in particular a packaging method for avoidance of wrinkles in the packaging film of the finished packaging and a device for implementing this Procedure.

In the vacuum film packaging process, an object becomes wrapped in a thermoplastic packaging film so that the film lies against the packaged object. In a known vacuum film packaging method (US-PS Re. 30 009), an object between two packaged impermeable strip elements, one of the strip elements made of heat-softenable and malleable plastic material due to air pressure differences is sucked against a concave surface in a vacuum chamber, the shape of which is chosen so that it can

partially enclosing the packaging item; while the barometric pressure differential is maintained, the one becomes concave The surface is heated to at least the forming and softening temperature of the strip element; then the Object between the strip elements in the vacuum chamber brought in; then the space between the strip elements is evacuated, while by the difference in air pressure the one strip member is held in contact with the heated concave surface; after that will

3Q is the air pressure on the outside of the retained Strip element increased so that it separates from the concave surface, thereby removing the retained strip element collapses over the object and rests against it and the other strip element; eventually the Strip elements sealed around the item. This verse

driving is also called a double-chamber vacuum film packaging process.

A modified packaging method (US-PS 3 83 5 618) is particularly suitable for multiple vacuum film packaging, where several items are packed at once. In another process (US Pat. No. 3,950,919) an object is vacuum-packed between two flexible films. Another packaging method (US-PS 3 736 721) a single film is arranged in a U-shape around the object and, due to pressure differences, on it Adapted shape.

In the case of vacuum film packaging, more or less wrinkles occur in the packaging film in the finished packaging. In order to avoid this disadvantage, shrink films have been used (US Pat. No. 3,956,867). Another! Possibility is ru stretch the packaging film in the middle near the object to be packaged towards the edges.

The object of the invention is, in a vacuum film packaging process, in which one or more packaging parts in one or more recesses in formed in a vacuum chamber and then dropped together on an object to be packaged in order to to adapt to its shape, to reduce the formation of wrinkles to a minimum.

This task is in accordance with a packaging method The preamble of claim 1 is solved with the aid of the features characterized in this claim.

AD ORIGINAL

With the invention, a packaging method is created, in which the vacuum packaging chamber of a vacuum film packaging device is ventilated so that excess Packaging material is shifted to the edges of the packaging, where it can later be cut off can. The area near the center of the chamber is ventilated first, while the edge areas ventilate last will. Since the vacuum is maintained in the outer areas, the film is in the edge areas held and thus suppresses the formation of wrinkles in the central areas of the film, while this over the Object collapses.

With the invention, a vacuum film packaging device is provided

driving improved, so that has the following steps:

An object is placed between parts of the packaging in a vacuum chamber, which has a concave closure.

has p _{n which} is in engagement at its periphery with at least one of the packaging parts; then the space between the closure and the packaging part which is engaged therewith is evacuated in order to pull the packaging part against the closure; then the area between the packaging parts is evacuated; thereafter the vacuum created first is released so that the packaging part which is engaged with the closure collapses and is formed onto the object; Finally, the packaging parts are sealed around the object at the outer edge. The improvement consists in the fact that the vacuum initially built up is relieved in zones in the closure on the edge of the packaging part which is in engagement therewith, so that excess packaging material is displaced to the edge of the finished packaging, thereby reducing the formation of wrinkles. Before-

preferably, in this method, the closure is selectively heated in order to reduce the tapering of the disproportionate Balance the packaging material.

° With the packaging device according to the invention a device for a vacuum film packaging process improved, in which an object between packaging parts in a having a concave closure Vacuum chamber is brought with at least one

Packaging part is engaged. The known packaging device has a device for evacuating the area between the closure and that with it in Engaging packaging part. To suck the packaging part against the closure; a facility for

Evacuation of the area between the packaging parts, a device for dismantling what was initially built up Vacuum so that the part of the package which is engaged with the closure collapses and attaches itself to the object applies and a device with which the packaging parts are sealed around the object are provided. The improvement of the packaging apparatus is that it has a device with which the vacuum initially built up in the closure on the edge of the packaging part engaged with the closures is broken down in order to shift excess packaging material to the edge of the finished packaging and reduce wrinkling. The packaging device preferably has a device for selective

ven heating of the closure, causing a disproportionate

BATH ORIGINAL

moderate tapering of the packaging material is compensated.

The invention is explained in more detail below with reference to figures. Show it:

Figure 1 is a schematic cross section through a packaging device, which represents the first step of the vacuum film packaging process,

in which the packaging film with the help of vacuum against the concave seal of the vacuum chamber is sucked;

Figure 2 is a is shifted to the following Figure 1 in an intermediate step of the process, wherein the excess packaging material to the edge, by passing the film ^υ stepwise applied article to be packaged upon the collapse of the; and

Figure 3 the last step in which the film has collapsed and adhere to the shape of the too

has adapted to the packaging item, with 25

excess film material on the edge of the

finished packaging has accumulated.

Figure 1 shows schematically a variant according to the invention _ Delte vacuum film packaging device and releases at the same time the first step of vacuum packaging again. The basic type of device is essentially one Vacuum film packaging device with two vacuum chambers. The vacuum film packaging device 10 has an upper lock 11 and a lower chamber 13.

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The inside 12 of the upper closure 11 is preferred concave in the v / es borrowed. Inside the lower chamber 13 there is a support plate 14 which carries the objects 20 to be packaged. Through the concave upper closure 11 run vertically several vacuum channels 15, which with the concave inside 12 and with Above the upper closure 11 arranged collecting lines 16, 17a, 17b are in connection. The inner the lower chamber 13 is connected to a lower collecting line 18. In a typical packaging operation is an object to be packaged in film 20 on a lower packaging part 21, which in turn is on the Support plate 14 rests. An upper packaging part 19 is located above the object 20. Usually

the packaging parts 19 and 21 consist of strips of flexible packaging material, preferably made of thermoplastic material such as polyethylene, polypropylene, Saran, nylon, polyvinyl chloride and the like, as well as composite films made from any of these materials. Preferably the packaging parts 19 and 21 are impermeable to gas.

When using the vacuum film packaging device 10, the upper closure 11 is first of the lower Chamber 13 removed so that its interior is accessible. The lower packaging part 21 is on the platen 14 placed and the article to be packaged 20 thereon. The upper packaging part 19 is initially under the arranged upper shutter 11 and then pulled into the concave inside 12, in which the air between the concave inside 12 and the upper packaging part is suctioned. This first step in creating a vacuum is carried out in that via the vacuum channels 15, which open into manifolds 16, 17a, 17b, their-

^ on the one hand with vacuum sources not shown in connection

ORIGINAL

stand, a vacuum is created. Vacuum means here that the range is partly up to the desired Degree is evacuated. When evacuating the area between the upper packaging part 19 and the concave ^ Inside 12, at least as much air is sucked out that the upper packaging part 19 touches the concave inside 12 is sucked and lays on it. Preferably, the upper closure 11 is heated, for example by a Series of steam pipes 22 which extend through the area of the upper headers 16, 17a, 17b, so that the thermoplastic packaging film is heated to its softening and forming temperature, after which it is in the concave inside 12 was drawn. Thereafter, the upper shutter 11 is lowered over the lower chamber 13, so that it is closed for further evacuation. The upper packaging part 19 stands on its outer edge engages with the upper closure 11 by resting it on the lower chamber 13. The area between the Object to be packaged 2 0 and the upper packaging part 19 is then applied by applying a vacuum to the lower manifold 18 evacuated. During this second evacuation step, the area around the object 20 becomes essentially evacuated to a negative pressure of about 510 mm of mercury, the negative pressure not being as great is, as in the first evacuation step, in which the upper packaging part 19 at a negative pressure of about 740 ram of mercury was formed. This restriction of the negative pressure is used to ensure that the upper packaging part 19

during the second evacuation step in the region of the object 20 in contact with the upper closure 11 remain. At this stage in the process, the vacuum film packaging devices are 10 and the packaging parts 19 and 20 are arranged according to FIG.

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In Figure 2, the next process step of the invention is Vacuum packaging process shown, in which the upper packaging part 19 on the object 2 0 is applied. This step is carried out in that the vacuum initially generated is gradually removed from a Area above the article to be packaged 20 to the peripheral area of the concave inside 12 of the upper closure 11 is dismantled. Especially at the beginning, the vacuum is reduced by opening the first collecting line 16 is connected to the outside air. However, the vacuum in the second collecting line 17a and in the third manifold 17b maintained so that the outer regions of the upper packaging part 19 with the Edge areas of the concave inside 12 in contact 5

stay. The purpose of this gradual application is that excess packaging material is on the outside of the finished product Packaging collects. The reduction of the vacuum in the first collecting line 16 can thereby preferably be completed be that the first manifold 16 is connected to a high pressure source, whereby the application movement of the upper packaging part 19 downwards the object 20 takes place better and more evenly. In addition, the relative expansion of the collecting line can

^ lines 16, 17a and 17b over the upper lock 11 can be set optionally. For example, if the expansion of the second manifold 17a and the third The manifold 17b is enlarged and the size of the first manifold 16 is correspondingly reduced,

the packaging width decreases. With this option, the packaging width and the circumferential edge can be optimally selected for each packaging material and each shape of the article 20 to be packaged.

BATH ORIGINAL

In Figure 3 is the final step of the packaging process reproduced, in which the upper packaging part 19 has sunk down completely and conforms to the shape. of Item 20 has adapted. This lowered state is achieved by the fact that the vacuum in the outer

ren second manifold 17a and the outer third Manifold 17b is dismantled as described above by connection with the outside air. The upper part of the packaging 19 collapses over object 20 due to the pressure differential created by the upper packaging part 19 and the concave, upper closure 11 under atmospheric pressure or under positive pressure stand while inside the lower chamber 13 there is a pressure below atmospheric pressure. The step

-j 5 wise reduction of the first prevailing vacuum above the Upper packaging part 19 results in excess packaging material on the outside of the final package collects, as indicated by arrow 25. The seal 26 between the upper part of the package 19 and the lower packaging part 21 is carried out after the upper packaging part 19 is on the item 2 0 and the lower packaging part 21 was collapsed. The seal 26 can be different Way to be executed. For example, the opposite surfaces of the packaging parts be coated with a heat-activated adhesive. If then the packaging film by contact with the heated concave inside 12 is heated, the adhesive is activated; when the upper part of the package

19 collapses around object 20 and comes into contact comes with the lower packaging part 21, a lock is established by the adhesive. When using of polyethylene packaging strips supplies for example a coating of ethylene vinyl acetate 35

a sufficient heat activated adhesive. One Another possibility of sealing consists in sealing the upper surface of the lower packaging part 21 with one of the Material of the upper packaging part 19 corresponding

To coat material so that these materials are at 5

glue or seal them together with sufficient heat. Another sealing procedure is based on an adhesive that can be activated by pressure or heat can be applied to the surface of the lower packaging part 21. - | q gen, the heat inside the chamber making the adhesive activated. Finally, the outer edge of the final package is used for removal of excess packaging material trimmed, which is on the outer edge of the upper

Packing part 19 has collected.
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In a further embodiment, the concave, Upper closure 11 heated in zones when a thermoplastic strip is used as the upper packaging part 19 will. In particular, individual areas of the upper closure 11 are heated during the zone-wise heating, so that the hottest zones correspond to the areas of the film that collapse onto the packaged Object 2 0 become the least thinner, while the coldest zones correspond to the areas of the film that

become most thinner upon collapse on object 20. With the term "get thinner" here is one disproportionate thinning of the collapsed film meant, for example, near the top corners of the object 20 to be packaged occurs, in particular when the object 20 is very high, that is to say approx. 5 cm or more. The area in which the film thins least is usually on top of that to be packaged Item 20. The zonal heating of the upper closure 11 can be achieved in that

BATH ORIGINAL

the amount of heat flowing through the steam pipes 22 of the upper manifolds 16, 17a, 17b is varied. the Zone-wise heating can also be carried out by supplying heated air to the vacuum channels 15, ρ- where the heating varies from vacuum channel to vacuum channel will. The zone-wise heating is carried out before or during the application of the film, which is shown in FIG. 3 in their applied form is shown.

The foregoing description illustrates the application of the invention to a US Pat. No. Re. 30 009 known method and an apparatus shown there; however, the device is to be understood in a general way. For example, can the invention in a method and an apparatus

according to US Pat. No. 3,835,618, in which ir.it aid

a vacuum film packaging device having two vacuum chambers multiple items are packed in multiple packaging. The invention can also be similar in the case of a Vakumm-20 equipped with a vacuum chamber

Film packaging apparatus according to US Pat. No. 3,950,919 can be used, which is directed to a two-lane vacuum film package, wherein the upper and lower closures of the vacuum chamber are concave. Locking _{I -?} Lent the invention in vacuum chambers in accordance with US-PS 3,736,721 may be used, which is directed to a vacuum film package of a U-shape around an object to be packaged folded web.

So far, in the description of a two-stage application of the upper packaging part 19 to the packaging item 20 assumed; however, is the number of stages in releasing the first vacuum state variable. It can be used by the user for any form of packaging

be optimized. For example, for multiple

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packaging in which two or more objects are vacuum-packed in foil at the same time, a three-stage Reduction of the first vacuum state advantageous. In the first stage, the packaging film is applied to each of the packaging objects of the multiple packaging applied, while the film in the areas between the Objects is held on the closure. In the second stage, these are recorded in the meantime Areas ventilated so that the packaging film in

the spaces between the objects of the multiple packaging coincides. Finally, in the third stage, the edge area of the packaging film is held released as described above.

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Claims (8)

Claims 1.) Process for the production of a vacuum film packaging with the following steps: arrangement of an object between packaging parts in a vacuum chamber with a concave closure attached to his Circumference engages at least one of the packaging parts; Evacuate the area between the Closure and the packaging part which is in engagement with it, in order to this against the closure draw; Evacuating the area between the packaging parts; Release of the vacuum generated first, so that the packaging part engaged with the closure collapses and adheres to the object creates; and finally sealing the packaging parts at the edge around the object, thereby characterized that the initially generated vacuum to zone by zone in the closure in the direction of the edge of the packaging part which is in engagement with this is degraded so that superfluous material of the packaging part is shifted to the edge of the finished packaging and thus the tendency to form wrinkles is reduced. 2. The method according to claim 1, characterized in that thermoplastic film strips for the packaging parts are provided that are practically impermeable and that the closure is heated in zones so that the hottest zones correspond to the areas of the foils engaged with the closure, which are least diluted when they collapse on the object. 3. The method according to claim 1 or 2, characterized in that the engaging with the closure Packaging part is held in contact with the closure, while the area between the packaging parts is evacuated and that the vacuum initially built up by connection to a high pressure source is dismantled. 4. The method according to any one of claims 1 to 3, characterized in that several objects at the same time be packaged and that the vacuum initially generated is released in three stages, with an intermediate stage the application of the film in the areas between the objects is prevented. 5. Devices for carrying out a vacuum film packaging process, in which an object (20) between packaging parts (19, 21) in a vacuum chamber introduced v / earth, the concave closure (11) on the circumference with at least one of the packaging parts (19, 21) is in engagement, with a device for evacuating the area between the closure (11) and the packaging part (19) engaged therewith in order to close it against the closure (11) draw; with a device for evacuating the area between the packaging parts (19, 21); with a device (16, 17a, 17b) for reducing the vacuum generated first, so that the one with the closure (11) engaging package portion (19) collapses and rests against object (20); and with a device for sealing the packaging parts (19, 21) at the edge around the object (20), characterized by means of a device for the gradual reduction of the vacuum initially generated in the closure (11) towards the edge of the packaging part (19) engaged with the closure (11) in order to remove excess To shift material of this packaging part (19) in the direction of the edge of the finished packaging and around to reduce the tendency for wrinkles to form. 6. Apparatus according to claim 5, characterized by a device for zone-wise heating of the closure (11) so that the hottest zones in the areas of the lock (11) engaged standing packaging part (19) correspond to the collapse on the object (20) on at least dilute. -A- 7. Devices according to claim 5 or 6, characterized by a device which is connected to the closure (11) engaged packaging part (19) in contact with the closure (11) holds during the Area between the packaging parts (19, 21) is evacuated and by a device through which the vacuum initially generated can be broken down by connecting it to a high pressure source. 8. Device according to one of claims 5 to 7, characterized by a device with which the first The vacuum generated is released in three stages, with an intermediate stage preventing the film from being in is applied to the areas between the objects to be packaged at the same time. BATH ORIGINAL