WO2003035382A1 - Method for compacting empty plastic containers and press for carrying out said method - Google Patents

Abstract

According to the invention, in order to transport empty PET containers, said containers are compacted to form a packet (18) and are held in the compacted state by means of encompassing means (28). In this way, the transport volume of the containers is significantly reduced.

Description

 Process for pressing empty plastic containers and press for carrying them out

Reference to related applications This application claims priority from European Patent Application No. 01 124 371.4 of October 24, 2001, the contents of which are hereby incorporated by reference into the present application.

Technical field

The invention relates to a method according to the preamble of claim 1. Furthermore, the invention relates to a press for plastic containers according to the preamble of claim 14.

State of the art While in many countries in the areas

Paper, glass, metals and organic waste has a longstanding recycling tradition and the material markets have more or less become established, the recycling of plastic waste is still comparatively rare. The separate collection and recycling of

Plastic packaging is ecologically superior to burning. However, for recycling to be considered, there must be a sufficient minimum amount of similar plastics. This is the case in the field of PET beverage packaging. A major advantage of PET (polyethylene terephthalate) over many other plastics is that this material can be further processed into high-quality products, i.e. there is no downcycling.

Due to the rapid spread worldwide, PET has gained great importance in the packaging industry and has become a sought-after raw material. For this reason, there is a great demand for recycled PET, PET is one of the plastics with a low environmental impact during production and disposal. There are the following possible uses for PET recyclate: in the textile sector as fillers for pillows, fibers for sports and fleece jackets, backpacks, sports shoes, carpet coverings, etc. In the packaging sector as yoghurt cups, margarine and bisque trays, etc. For the production of PET recyclate the decentrally collected PET bottles are transported to logistics centers, where they are sorted by color and quality and processed into 100 to 300 kg bales that can be stored temporarily. The sorted bottles are then processed into recycled material, and it is checked by hand and by machine whether all foreign substances have been excreted. The labels are then removed with steam and removed. The bottles (including the cap) are shredded into chips in a mill. These are prewashed, in order to then remove adhesive residues from them in a second wash cycle. The wash liquor can be used again for further washing processes. The clean cutlets are separated according to the plastic types PET (bottle body) and polyethylene (lid) due to their different densities (PET sinks in water, polyethylene on the other hand floats) and then dried, dusted and freed of any remaining metal parts. In a final step, the chips are homogenized in large mixers into batches with precisely defined values, filled into transport bags and fed to the respective work areas.

Decentralized collection and subsequent transport of the empty PET bottles requires a corresponding effort. Collection containers are placed at retail stores, in restaurants, offices or in leisure facilities. All collected PET Beverage bottles are then brought by transport companies to one of the PET logistics centers, where the recycling is done.

The reduction in the volume of the returned PET beverage bottles is essential for the lowest possible transport effort from the collection points to the logistics centers. With this measure, the number of transports can be reduced, which has a cost-effective effect on the entire logistics chain and thus the price of the PET recyclate. PET bottles can be pressed together at all stages of the disposal chain. Ideally, the flattening should take place as early as possible.

According to the state of the art, the PET bottles are either not pressed together at all or are pressed together by hand or with different types of presses and loosely in large, e.g. 110 liter plastic sacks filled. Depending on the type of pressing of the bottles, the total degree of compression of the ready-to-transport bottles results from 0% to approx. 40%.

It is known to press PET bottles into bales or packages and to hold them together by means of straps. Such packages result in a higher total compression and therefore require less transport capacity. The documents JP-A-2000 095219, JP-A-2001 259893 and JP-A-2001 087894 show large press lines in which many PET bottles are pressed simultaneously in a press room by a single press movement and then in a pressed form a channel of the press system can be ejected. At the end of the channel there is a gradual exit from the channel and bands are placed around the pressed package. These press lines are very large and therefore not suitable for direct use in shops. First, enough bottles have to be collected in these presses until they can be pressed into a package in one step. EP-A-0 941 941 shows different variants of waste presses, each in a waste press. if sack is pressed into it. In the case of a package made of PET bottles, which expands greatly when the pressure is relieved, these presses cannot achieve a high level of compression, since the press plate has to be moved out of the bag to remove the bag from the press. US-A-5 056 428 shows the pressing of vehicle tires, with no closed pressing space being provided for this. GB-A-1 537 659 shows a baler for cut paper material, GB-A-2 070 511 a baler for office waste and cardboard waste.

Presentation of the invention

The invention is based on the object of creating highly compressed packages from PET containers in a simple and space-saving manner. This enables such packages to be made available in stores where the containers are returned individually or in small numbers and at different times. This object is achieved in the method of the type mentioned by the characterizing features of claim 1.

Because the package is formed in several steps, each additional container can be added directly to the already pressed containers in the press, so that no separate storage space is required for the containers. This leads to a considerable downsizing of the system for pressing the package. The wrapping or wrapping of the package is preferably carried out in the same press room in which the package has been pressed. This means that the press system can be further reduced in size since no separate channel is required for the delivery of the pressed package and for its subsequent processing. The container to be added is preferably pressed directly onto the partial package. The package is held together by the enclosing means so that it forms a transportable unit. The enclosing means keeps the package in a pressed state, so that the compression of the finished package as a transport unit largely corresponds to that when the containers are pressed into the package. Cords or tapes that are arranged around the containers in the state that is pressed into the package are preferably suitable as encompassing means. The package is preferably formed in a container press which presses the individual containers together before or during package formation. Package formation is also possible in a separate press.

The packages are preferably cuboid or cubic in order to create transport units which can be arranged close to one another. For easy handling, the packages preferably have a weight of 10 kg to 20 kg.

Another object of the invention is to create a press by means of which a considerable increase in the overall degree of compaction of a large number of containers and thus a considerable reduction in the transport volume of a quantity of containers can be achieved.

This object is achieved in a press arrangement with the characterizing features of claim 14.

The fact that the press has, in addition to the pressing means for compressing individual containers, or possibly a plurality of containers at the same time, further means by means of which a pressed and held package can be produced from the pressed containers can result in a significantly increased overall degree of compression or correspondingly significantly reduced transport volume can be achieved. Brief description of the drawings

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. 1 shows a package of pressed PET bottles held with straps;

Figure 2 to Figure 9 shows an example of pressing a package with a hand press;

FIG. 10 shows a schematic view for explaining the overpressing of the package;

Figure 11 is a detailed view of the press plate and the holding means;

Figure 12 is a simplified view of a motor-driven press; Figure 13 is a simplified view of the back of the press;

FIG. 14 shows a detailed view of the holder of the press plate; and the

Figures 15 to 20 an example of the umwik- none of the package in the press.

Best way to carry out the invention FIGS. 1 to 9 schematically show the procedure according to the invention. The empty PET bottles 17 are pressed together to form a package 18, as is shown schematically in FIG. 1, and the package is held by encircling means, shown as straps 28 in FIG. 1, so that a transportable unit results. It has been shown that an overall compression of approximately 70-80% can be achieved in this way. The preferred embodiment according to the invention relates to the provision of PET bottles for transportation. However, the invention is not limited to this example, but is generally suitable for compressible plastic containers. In the following, PET bottles are used as examples. The formation of a compressed package from the bottles can be done in a variety of ways. Preferred and described in detail below with reference to a press is a procedure according to which the individual bottles are pressed together in a press and at the same time are pressed into a package in this press. Also in this press, the enclosing means is placed around the finished package so that the finished package can be removed from the press. However, it is also possible to use a different method to form packages: For example, individual or multiple bottles can be pressed together in a first press. Immediately afterwards or after an intermediate storage, the bottles that have already been pressed are pressed into a package in a further press, which has a press space in accordance with the desired package shape, and are held together with the encircling means to form the package. The press used for this purpose can have, for example, a cuboid-shaped press space, which is closed at the top by a press plate which, after filling the press space with a quantity of bottles corresponding to the desired package size or the desired package weight, reduces the size of the press space by hand or by motor , so that the bottles are pressed into a packet-shaped block. This block is then wrapped with ribbons or cords, for example, so that the package is formed. The wrapping is explained in more detail below using an example.

Another procedure could also be carried out in such a way that the unpressed bottles are filled into a press with a press space corresponding to the desired package shape, after which a press plate both presses the bottles together and forms the package from the compressed bottles. In this case, too, the shape of the package is stabilized by the enclosing means, so that it forms a transport unit. The packages formed are preferably rectangular and have a weight of approximately 5-20 kg, which results in an easy-to-handle form of transport for the bottles. Of course, other, for example cubic or cylindrical, shapes are also possible for the package. Depending on the filling of the bottles in the press room, there is a more or less orderly position of the bottles within the package. Large, ie 1 liter to 2 liter bottles are often arranged in the longitudinal direction of a cuboid package. Smaller bottles are also arranged in the longitudinal direction, but also in the transverse direction or at an angle. The bottles can be provided with a lid or without a lid, it being preferred if means, for example needle-shaped or spike-shaped elements, are provided on the respective press plate which can cause closed bottles to pierce. Such piercing is always guaranteed if the bottles are pressed together individually as described below. As mentioned, tapes or cords which hold the package can be used as a means of encirclement. Holding is understood to mean that there is a transport-resistant unit, which is generally guaranteed if the package is enclosed when the package is pressed together. The resilience of the compressed bottles results in a force acting on the encircling means, which prevents the encircling means from becoming loose. This keeps the package pressed together. Instead of ribbons or cords, it is also possible to use a film, for example a shrink film, as the encasing means, which holds the bottles pressed together in the form of a package. A sack can also be used, in which case it does not contain loose bottles as in the prior art, but rather includes the bottles pressed into a package in such a way that the pressed package shape is retained. A preferred method or a preferred press for producing the packet-shaped transport units from the PET bottles is described in more detail below. Figures 2-9 show different steps of pressing a bottle and adding it to the package. FIG. 2 shows part of a press 20 which comprises a support frame 10, on the top of which a hand press 11 is arranged. In this example, the hand press 11 is a manually operated toggle press which has a hand lever 14 which is only partially shown and by means of which the pressing can be carried out. From the hand lever 14, toggle levers, not shown, act on a press plate 15, this press plate preferably being formed from a multiplicity of individual, spaced-apart press members 15 '(FIG. 11) which form openings 15''between them. A movable limiting element 19 (lower press plate) opposite the press plate 15 below forms a support for an already formed partial package 18 'made of PET bottles, which is only shown as a block. This package is bounded all round by side walls of the press, not shown, these side walls, together with the lower press plate 19, forming the actual press space, which is delimited on its upper side by the upper press plate 15, which can plunge into the press space. The press room is therefore a closed, closed press room on all sides. Retaining means 16, which in this example are formed by a plurality of circular-segment-shaped disks, which can each be pivoted about a pivot axis 16 ', and which are arranged in such a way that they are in the region of the openings 15'', can further engage in the pressing area. the press plate 15 lie. The holding means can also be linearly displaceable plates which can be moved in and out laterally into the pressing space. Swiveling holding means are preferred. FIG. 2 shows an initial position in which a partial Package 18 'of pressed bottles is located in the pressing chamber, which partial package rests on the lower pressing plate 19 and is held in a pressed position by the holding means 16 from above. FIG. 2 further shows that a further bottle 17 to be pressed has been inserted into the press. In the example shown, this was done by a lateral insertion into the empty space below the press plate 15 and above the holding means 16. The bottle 17 rests on the preferably curved end faces 16 ″ of the individual disks of the holding means 16. FIG. 3 shows a first step which results after the bottle 17 has been inserted by actuating the hand lever 14. This is usually pressed down by the operator from the position shown. First, the holding means 16 are pivoted away from the partial package about the pivot axis 16 ', so that this is released by the holding means, which can be seen in FIG. 4. Due to the restoring force of the bottles held therein, the partial package 18 'expands upwards towards the pressing plate 15, so that the bottle 17 to be pressed rests on the upper side of the partial package 18'. The expansion of the partial package can result in a first compression of the bottle 17. By further depressing the operating lever 14, the

Press plate 15 pressed downwards in the direction of the press plate 19, so that, as can be seen in FIGS. 5 and 6, there is both a compression of the bottle 17 and a pushing down of the partial package 18 '. The bottle 17 compressed in the process is thereby added to this and the partial package is pressed again. In FIG. 7, the pressing plate 15 has reached its bottom dead center and has the partial package, now supplemented by the bottle 17, compressed so far that the upper side of the partial package 18 ′ lies below the lower sides of the holding means 16. These are pivoted again over the partial package 18 'and locked in this position. The operator The lever 14 has reached its lowest position. When it is released, the press plate 15 is moved upwards again through the holding means 16 (FIG. 8). so that in Figure 9 the space above the holding means 16 is again free for inserting a further bottle 17. The holding means hold the partial package 18 ′ in the pressed position in the pressed position. The pressing and adding to the partial package of a further bottle 17 now again takes place according to FIGS. 2 to 9. In this example, the holding means 16 are thus motion-coupled to the press plate, for example via a lever arrangement. However, rigid, immovable holding means could also be arranged which do not pivot away as long as the pressing plate can press the container onto the partial package through the holding means and this is sufficiently retained.

So that a package can be formed in the press chamber, the lower press plate 19 is arranged to be movable in the vertical direction. If no partial package has yet been formed in the press, the lower press plate 19 has been moved all the way up, so that the first bottle of the package is pressed between the press plate 15 and the press plate 19. The further bottles which are then added each increase the force acting on the lower press plate 19 at the bottom dead center of the upper press plate 15. The lower press plate 19 is preferably arranged such that it can be moved downwards by a unit length when a predetermined force is exceeded, which increases the volume of the press room. Of course, the increase in volume of the pressing space can also be brought about in a manner other than force-dependent, for example after a predetermined number of pressing operations. Additional bottles can then be pressed into the partial package that is now being formed in the enlarged pressing space, with another each time the increasing number of bottles leads to the release force for the lower pressing base 19 being reached The same process takes place down one length unit (instead of a movable press base 19, a press plate 15 with a variable maximum press stroke could also be provided). In this way, the partial package 18 'gradually forms in the press room. This process is completed when the press plate 19 has reached the lowest point of its possible travel. The package 18 is then complete or, if necessary, is further completed until the maximum permissible pressing force is then also reached. A corresponding display can show the operator that the package is now completely formed in the press room. A position as shown in FIG. 9 then results, the package 18 now being the complete package and no longer a partial package. The package is in the pressed position by the upper press plate 15 or the holding means 16 held in this in the press space of the press 20. Subsequently, the encircling means are attached around the package, which will be explained later, and after that it can Package can be removed from the press after lowering the lower press plate 19 and / or moving the upper press plate 15 upwards. FIG. 9 shows the holder in the pressed position by the holding means 16, but it is preferred if, at the end of the package formation, the press plate 15 compresses the package and the tapes are wrapped in this press position.

FIG. 10 shows a preferred partial aspect during pressing, according to which, when the partial package 18 'or the package 18 is pressed by the pressing plate 15, the lower side of the pressing plate is pressed by a predetermined amount d, preferably 10 to 30 mm, preferably approximately 20 mm , is moved further down than the lower edge of the holding means 16. It has been shown that by pressing the package further down than would actually be necessary for pivoting or retracting the holding means, the restoring force of the package is substantially reduced, approximately 10 times, so that the holding means or their bearing must accordingly absorb lower forces, which significantly simplifies the construction of the press. FIG. 11 shows a more detailed view of a partially open press 20, in which view the toggle actuation of the press plate 15 and its configuration from individual plates 15 with openings 15 ″ in between can be seen better. Also visible are the individual disks of the holding means 16 with their pivot axes 16 'and the insertion opening 21 for empty containers. The coupling of the axes of the holding means to the lever for driving the upper press plate is not shown. FIG. 12 schematically shows a view of a motor-driven press, which basically works in the same way as the hand press previously shown. Instead of manual operation, however, a motor-driven press with a motor 31 is provided, and an automated feed that automatically feeds the bottles from a double trough 32 into the press.

The trough 32 rotates after inserting a container to be pressed, so that it is moved towards the pressing chamber.

The same reference numerals as used up to now denote functionally identical parts of this motor-driven press 20 '. The levers for the upper press plate 15 are driven from the engine, for example via a gear and a chain drive. The holding means 16 are moved, for example, via a cam disc, so that they are also driven by the motor 31. A pivotable plate 32 'can safely empty the trough 32 and convey the container to be pressed into the pressing space and close it to the trough 32 during the pressing process. Figure 13 shows the back of the motor-driven press 20 '. The wrapping tapes are guided into the press space via the tape feeds 33. There they can be guided in channels 35 of the lower limiting element 19, so that the package is formed above the belts. On the front side 36 and in the interior of the pressing space, the belts are led upwards again, so that they extend along both sides of the package. When the package is completely pressed, the belts are brought by feed means on the top of the package through the press plate 15, which holds the package pressed, from the back of the press to the front, where they are connected to the free end of the band, for example by welds, and cut off. In this example, the lower limit is

19 attached to a driven rotatable threaded spindle 50 (thread not shown) so that the base plate 19 is driven and can be moved down and up. If the pressing force is so great that the spring 51 is compressed so much that there is contact with the sensor 52, the lower limit 19 is moved downwards to enlarge the pressing space until the distance at the sensor again corresponds to the target distance or move down a predetermined amount.

Alternatively, for example in the case of the hand press 20 already described, the press base or the lower press plate 19 could be mounted on the press frame 10 so as to be movable by means of a roller guide. The lower press plate 19 could be attached to a chain which is deflected and connected to a slip clutch via a chain wheel. The slip clutch is a commercially available element which rotates by a predetermined angle of rotation when a predetermined force is exceeded. In this way, the pressing base 19 moves downward when a predetermined force acts on it, which overcomes the force setting of the slip clutch. increases. This then spins until the set force is undershot again; thus the press floor also moves downwards. Thereafter, the pressing can be carried out again at this height of the press plate 19 until the force set again

Slipping clutch is exceeded. The limitation of the pressing force by the slip clutch can also prevent the destruction of glass bottles which have been mistakenly inserted into the press. The slipping clutch also allows the press base 19 to move upward substantially free when the package has been removed from the press space and the formation of a new package is to begin. To do this, the clutch is disengaged. In order to move the press base 19 upwards, drive means (not shown) that can be actuated manually or by motor could be provided.

FIGS. 15 to 20 show the attachment of a surrounding means around the package in a simplified manner, which in the example shown is a cord or a band 38 which can be pulled off a roll 40. In the figures, the press is only shown schematically, insofar as this is necessary to understand the scope. FIG. 15 shows how the cord 38 or, if need be, a plurality of cords 38 arranged at a spacing in parallel, is pulled over the press base 19 in its upper position after an already formed package has been removed from the press. The door 22 of the press is open. The cord 38 is now pulled over the press base 19 and then the door 22 of the press is closed and the cord 38 is pulled further out of the press. This can be seen in FIG. 16. In the example shown, the part 45 of the cord hanging freely at the front of the press and the roller 40 form a supply of the encircling means which is used to form the package. FIG. 17 shows a subpackage 18 'formed, the bottom press base 19 of which has moved downward, so that the front and rear a cord section 41 and 42 has been pulled from the front free end 45 or from the roll 40 in the pressing chamber. In FIG. 18, the package 18 is finished and the cord 38 is pulled from behind over the upper end of the package, which is indicated in the drawing by a hook 43. Since the upper press plate 15 consists of individual gates which form an empty space between them, it is possible to pull the cord 38 from behind through the press plate 15 over the package. FIG. 19 shows how the two cord ends on the front upper side of the package are connected to form a knot 44 after the cord has been cut off. The same is done with any other cords placed around the package in the manner shown. The node 44 is formed as long as the package is still pressed by the press plate 15. Only after the cords have been tied is the upper press plate 15 moved upward, so that the package 18 is exposed, which can be seen in FIG. 20. The package 18 can then be removed, for which purpose the pressing base 19, as explained, is at most moved downwards, whereupon the process according to FIG. 17 begins again. The motor-driven press shown previously is operated in a similar manner, but the tape supply is preferably on the roll and is deducted from it when the package is formed.

Instead of the cords shown or already explained weldable tapes, e.g. plastic straps are also used, which are closed by a clip for strapping. Corresponding systems are known and need not be described further here.

Claims

claims 1. A method for producing a transport unit (18, 28) from essentially empty, compressed plastic containers (17), in particular from unsorted PET bottles, for transporting the same for recycling, wherein in each case a plurality of containers (17) form a package ( 18) pressed and held in package form by a wrapping means (28, 38) and is thus provided as a ready-to-transport parcel and the wrapping means (28) holds the parcel in a pressed state and is a wrapping means (28) or a wrapping agent which is in the pressed state of the package is arranged around it, characterized in that the formation of the package takes place in several steps by adding individual or more containers (17) to an already pressed partial package (18 '). 2. The method according to claim 1, characterized in that the containers are pressed together before the formation of the package or the partial package. 3. The method according to claim 1, characterized in that the containers are pressed together during the formation of the package or partial package. 4. The method according to any one of claims 1 to 3, characterized in that the containers are pressed together in the same press (20) in which the package is formed. 5. The method according to any one of claims 1 to 5, characterized in that the containers are pressed together in a first press and the package is pressed in a second press. 6. The method according to any one of claims 1 to 5, characterized in that in the press (20) a pressing together of the container (17) between a press plate (15) on the one hand and a partial package (18 ') made of containers on the other hand. 7. The method according to any one of claims 1 to 6, characterized in that in the press (20) a partial package is held in the pressed state by holding means (16, 16 ') acting on the partial package. 8. The method according to claim 7, characterized in that when the partial package is pressed, the package is pressed to a smaller package size, preferably to a 10% to 30% smaller partial package height, than is predetermined by the holding means. , Method according to one of claims 1 to 8, characterized in that the containers are pierced during pressing, in particular by piercing means (15 ') arranged on a press plate (15) of the press. 10. The method according to any one of claims 1 to 9, characterized in that a container to be pressed initially rests on holding means (16), which hold the partial package in the pressed state, so that the holding means when the press plate (15) of the press (20) moves in the direction of the partial package ( 18 ') release it so that the container is pressed between the partial package and the press plate. 11. The method according to any one of claims 1 to 10, characterized in that the wrapping means (28) or wrapping agent is arranged in the press room around the package. 12. The method according to claim 11, characterized in that the wrapping means or wrapping means is arranged around the package while it is held in a pressed state by the press plate (15) of the press or by the holding means (16, 16 '). 13. The method according to any one of claims 1 to 12, characterized in that the wrapping means is formed by plastic strips, the ends of which are welded together. 14. Press (20) for producing a transport unit (18) from compressed plastic containers (17), the press (20) having a press chamber and a pressing means (14, 15) for pressing containers (17) received in the press chamber. to a package (18) and a surrounding arrangement which, in order to enclose the containers pressed to the package in the pressed state, is equipped with at least one surrounding means (28, 38) remaining on the package, characterized in that the press for forming the package in several steps by adding individual or several containers (17) to an already pressed partial package (18 ') and having holding means (16, 16') by means of which the partial package can be held in the pressed space in the pressed state. 15. Press according to claim 14, characterized in that the holding means comprise a plurality of holder plates (16, 16 ') which can be retracted or swiveled into the closed press space. 16. Press according to claim 14 or 15, characterized in that the holding means are drive-connected to the press drive or have their own drive which is connected to the press drive in terms of control, such that the holding means depends on the position of the press plate (15) Press can be retracted and extended into the press room. 17. Press (20) according to one of claims 14 to 16, characterized in that the volume of the pressing space by at least one movable, in particular pressure-dependent movable, the pressing plate (15) opposite limiting element (19) between a minimum volume and a maximum olumen is changeable. 18. Press (20) according to one of claims 14 to 17, characterized in that the holding means on at least one upper boundary of the pressing space as pivoting about a pivot axis (18 ') in the pressing space, or swinging out of this, holding discs (16) excluded are designed, a plurality of holding disks spaced apart from one another each being arranged on a common pivot axis. 19. Press (20) according to one of claims 14 to 18, characterized in that the pressing means is a pressing plate (15) which has recesses through which the pressing plate can pass through the holding means. 20. Press (20) according to one of claims 14 to 19, characterized in that the enclosing means can be guided from the enclosing arrangement into the pressing space and can be traced from a supply when the pressing space is enlarged. 21. Press according to one of claims 14 to 20, characterized in that the encircling means is formed by a plurality of belts, each of which can be guided into the press space from a roll and are guided in recesses in the delimiting element (19).