The present invention relates to an apparatus for compacting empty plastic (PET) bottles, containing a base plate, a vertical guide bar mounted to said base plate and a heating- compressing unit.

Soft drinks and other food products are growingly sold in plastic containers, and the manufacturers increasingly apply disposable containers instead of reusable ones. Therefore, there is a huge amount of such containers in the garbage dumps as well as in the nature. Accordingly, they pollute nature on the one hand, and increase the volume of the garbage on the other hand.

A further problem is that plastic materials do not decompose, which means that these containers pollute nature and need huge room in the garbage dumps for a long time.

In order to eliminate this problem at least to a certain degree, there are numerous suggestions for indoor crushing or compressing these containers.

However, this can not be solved easily, as plastic containers can not be compressed like metal objects, because they gain back most of their shape after having been compressed. Compacting plastic containers or bottles can only be effective, if the device for compressing the bottles contain means for heating as well. In this case the bottles can not increase their volume as a result of their flexibility, when compacting pressure is over. If the compressing is carried out combined with heat effect, the compacted bottles keep their compressed shape after cooling.

The devices used for compacting plastic bottles generally contain a housing or base for receiving the bottles, heating element and means for compressing.

EP 0707932 discloses a compactor wherein a housing provided with heating element receives an empty bottle, and a metal fork is arranged on the neck part of the bottle. Said fork is moved downward by a spindle, and compresses the bottle from above. The spindle can be operated manually.

The device for reduction of plastic waste according to FR 2668732 contains a lower compartment with a fan to pulse hot air via an electrical resistance element into a volume containing the container to be compressed. A movable plate guided by a spindle driven with an electric motor compresses the bottle. There are devices, wherein the bottle is heated along its whole length with wall heater and/or with heating patron intruding into the bottle. Such device is known e.g. from FR 2692190.

In the devices outlined above, the bottles are generally heated from below and compressed from above and the heating is not restricted to any part of the bottle. Therefore, the different heated sections of the bottle are layered on each other inordinately and maximum compaction can not achieved.

According to FR 27112230, an internal heating module is arranged centrally in the compactor device, and the bottle is compressed with two pushers from both sides. The disadvantage of this construction is that the power consumption is unnecessarily increased, meanwhile the device is rather complicated and expensive.

WO 03/059606 discloses an apparatus for compressing plastic bottles, wherein a housing or frame is constructed to receive the bottle with its mouth part upwards, the heating element or the part of the heating element surrounding the bottle is at most 60 mm high, and is arranged around the neck part of the bottle in its starting position and the fixing element is a sealable plug in the compressing means, to be fitted into the mouth of the bottle and having an air channel, the cross section of which is preferably adjustable. This construction eliminates several disadvantages of the state of art, but it is rather voluminous and can only operated in many steps.

JP 2004114809 discloses an apparatus for volume reduction treatment, wherein compression begins from the mouth part of the bottle. This goes with the problem that the heating element is rather far from the wall of the bottle, when the compression is in the first phase, and is therefore ineffective. As a result, the power consumption increases together with the time needed for compression and, at the same time, the rate of compression decreases (the volume of the compacted bottle is 1/12 part of the original volume). Moreover, it may be important in case of selective waste collection, that the identification mark at the mouth part of the bottle should remain readable, which can not be achieved, when the compression is beginning at the mouth part of the bottle. Object of the present invention is therefore to provide a solution, which enables compressing and and/or volume reduction of plastic bottles a more effective, quick and cheep way, than with the state of art.

This object can be achieved with a device according to claim 1 of the present invention, the device containing a base plate, a vertical guide bar mounted to said base plate and a heating-compressing unit, wherein said base plate is provided with one or more supporting elements adapted to hold the mouth part of the bottle; said heating-compressing unit receiving the bottom part of the (PET) bottle contains a fan arranged centrally in the upper part of a cup shaped housing and a heating wire arranged in the lower part of said cup shaped housing along the periphery of the housing, and the upper part of the housing is provided with suction openings. Within said housing there is an inner cup which is fitted to the bottom part of the (PET) bottle and provides, together with the outer cup, a flow space containing the fan in the upper part and the heating wire in the lower part. The inner cup is provided with several air guide channels connecting the space below said inner cup surrounding the bottom part of the (PET) bottle and exhaust openings arranged in the upper part of the outer cup.

Further features of the invention are described in the subclaims.

Basic advantage of the present invention is that a regular, reproducible compress is achieved as the result of the compaction, wherein the volume of the compacted bottle is 1/16 part of the original volume. Further to that, the identification mark on the neck part of the bottle remains intact, and both the power consumption and the compressing time is reduced with respect to the state of art.

Further details of the invention will be explained by examples and drawing, wherein:

Fig.l is the cross section of a preferred embodiment of the apparatus according to the invention, and

Fig.2 is a section along line II - II of Fig.l.

The apparatus shown in the drawing consists of a base plate 1, guide bar 2 and a heating- compressing unit 3. The bottle 4 to be compacted is arranged in the apparatus mouth part 5 down, wherein the mouth part 5 is received by one of the supporting elements 6, 6a. Supporting element 6a provide support for bottles with small mouth parts, meanwhile supporting element 6 supports bottles with bigger mouth parts. The bottom part 7 of the bottle 4 is received by the heating-compressing unit 3, which holds the bottle 4 by its weight. The housing of the heating-compressing unit 3 is an outer cup 8, which is provided with a fan 9 on the inner upper side thereof. The outer cup 8 is also provided with suction openings 10 above the fan 9. Below the fan 9 there is a second, inner cup 11 arranged within the outer cup 8, providing, together with the outer cup 8, a flow space 12. In the lower part of the flow space 12, between the inner surface of the outer cup 8 and the outer surface of the inner cup 11, there is a heating wire 13. Below this heating wire 13, a baffle 14 is arranged for directing the heated air arriving from the flow space 12 to the wall of the bottle 4. The apparatus is provided with several baffles 14a, 14b, which are interchangeable depending on the measures of the bottle. The drawing shows a greater bottle 4 with full line, and a smaller bottle 4 is shown with dotted line.

The air arriving through the suction openings 10 is directed into the flow space 12 by an air baffle cone 15 arranged on the top of the inner cup 11. At the bottom of the flow space 12, the air flows around the heating wire 13 and is directed to the wall of the bottle 4 by baffles 14. In order to achieve that the hot air should heat only the side wall of the bottle 4, flow space 12 is connected with exhaust openings 17 on the top of the outer cup 8 by guide channels 16, which deflect the hot air way from other parts of the bottle.

During use of the apparatus according to the invention, the bottle to be compacted is arranged mouth part 5 down on an appropriate supporting element 6 or 6a, and the heating-compressing unit 3 is lowered until it reaches the bottom part 7 of the bottle. Then, the heating wire 13 and the fan 9 is switched on by a switch 18 arranged on the guide bar 2, and heated air is flowing to the given part of the wall of the bottle 4, which is then softened. The weight of the heating-compressing unit 3 compresses the softened part and the heating wire heats then the next section of the wall of the bottle, meanwhile the bottle is continuously shrinking. All the compressed parts are collected practically within the remaining bottom part 7, and only the mouth part 5 extends from the compressed bottle.

As the hot air contacts the wall of the bottle only in a restricted small strip zone before living through the guide channels, compaction is carried out regularly, under uniform pressure and a standard compress is achieved, wherein the identification code is clearly visible on the neck part.

Due to the construction of the heating-compressing unit and as a result of the regular compression, the volume of the compress decreases to the 1/16 part of the volume of the bottle, which is far better, than that with the prior art devices. At the same time, due to the reduced power consumption, the time needed for the compression is less about 4 -5 seconds than with the prior art processes.

The embodiment in the present disclosure is a possible example only, and a skilled person in the art can produce many variation within the scope claimed.