Device for reducing the volume of bottle made of plastic material

The apparatus according to the invention comprises a housing or frame for receiving the bottle, an element for fixing the bottle, a heating element surrounding part of the bottle and compressing means for compacting the softened bottle, wherein the 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, preferably with flow control means. The flow control means may be a valve.

CROSS REFERENCE TO RELATED APPLICATION

This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/HU02/00159, filed Dec. 20, 2002, and claims priority of Hungarian Patent Application P 0200176, filed Jan. 16, 2002.

BACKGROUND OF THE INVENTION

The invention relates to an apparatus for compacting empty plastic bottles, comprising a housing or frame, means for fixing the bottle, means for heating a part of the bottle and a press unit for compacting the softened bottle.

It is known that beverages and other food products are filled more and more often into plastic bottles for sale, and the manufacturers want to produce rather one-way bottles rather than repurchasable ones. Thus, these bottles are found in large amounts in waste yards or in nature, contaminating thereby the environment or increasing to a great extent the amount of waste.

A further problem is caused by the fact that the material of the plastics do not decompose, thus the damage caused by them is long-lasting.

In order to eliminate, at least partly, the above problem, a great number of suggestions were made for the domestic annihilation or compacting of such bottles.

The solution is not easy due to the fact that plastic bottles, as opposed to metal containers or boxes, regain a significant part of their volume after stopping of the compression. Thus, compacting can only be performed by using compacting and thermal effect simultaneously, wherein the thermal effect does not allow the bottles to increase their volume after ceasing of the compression, as a consequence of their elasticity. If, namely, bottles are compressed in their melted state, they do not change their form after cooling down.

Known bottle compactors generally comprise a housing or frame receiving the bottle, heating means and compressing means.

EP 0707932 discloses a bottle compactor containing a housing chamber designed to receive an empty bottle. The housing is provided with a resistor and a cursor, the end of which is formed like a fork engaging the plastic bottle at its neck part. The cursor with the fork compresses the heated and softened bottle from the upside down. The cursor can be operated manually by means of a lever.

FR 2694722 describes a portable device, wherein the power for compacting the bottle arranged in a housing having resistance heating is provided by a spring.

In the bottom of the apparatus described in FR 2668732, there is a separate heating chamber wherein air is heated by resistance heating and the heated air is pulsed by a fan into a volume containing the plastic bottle, which is compacted by a plate moved by motor driven spindles.

In all the above devices, the bottles are heated from below, and they are usually compressed from above. As a result, the folded plastic layers are irregular and, in this way, optimal compression can not be achieved.

In other devices, heating is provided along the whole length of the device and/or by means of a patron intruding into the bottle. Such an apparatus is described e.g. in FR 2692190. In this case, the above mentioned disadvantage, namely the irregular compacting is especially obvious and, in addition, the energy consumption increases significantly as well.

In FR 2712230 the disclosed apparatus has a closed housing with a central heater intruding into the bottle which is compressed both from top to bottom and from bottom to top. The disadvantage of this is the unnecessarily increased energy requirement of compression and, further on, it is complicated and expensive.

SUMMARY OR THE INVENTION

The object of the present invention is to provide a cheap and simple device for compacting empty plastic bottles to the maximum achievable degree and with a regulated, optimum compression rate.

Accordingly, the apparatus according to the invention comprises a housing or frame for receiving the bottle, an element for fixing the bottle, a heating element surrounding part of the bottle and compressing means for compacting the softened bottle, wherein the 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, preferably with flow control means. The flow control means may be a valve.

The compression means and the fixing element for the bottle is a lid or the like moving on vertical guide bars and compressing the bottle towards the base of the housing, by its weight. The lid can also be lifted and lowered by a spindle driven by an electric motor or by spring means.

Preferably, the diameter of at least one section of the plug is adjustable, being an elastic rubber or plastic sleeve and allowing the sealed closing of the mouth of the plastic bottle.

In a preferred embodiment, the height of the heating element does not exceed 60 mm in order to ensure the simultaneous melting only of a relatively thin layer. As a consequence, compacting takes place in regular, narrow bands providing thereby a fully compacted agglomerate.

According to another preferred embodiment, the height of the heating element is larger than 60 mm, but the device can be adjusted so that the bottle intrudes into the heating element only in a section shorter than 60 mm.

The apparatus according to the invention allows an efficient, regulated compacting of plastic bottles so that the bellows-like folding occurs on short sections. This can be achieved partly by the small-height heating element, partly by controlled compacting. Compacting can be controlled by changing the flow cross section of the airing duct in the plug.

From the viewpoint of controlled and efficient compacting it is also important that melting and pressing takes always place starting from the mouth piece of the bottle, so that the pieces of smaller diameter can be easily compacted into the following pieces of larger diameter.

In order to obtain maximum compacting, a preferred embodiment is provided with additional, mechanical compacting means.

Further details of the invention will be explained by means of embodiments illustrated in the enclosed drawings, wherein

DESCRIPTION OF THE PREFERRED EMBODIMENT

The device shown inFIG. 1comprises a base1, a housing2, spring means3and a bottle holder4in housing2. Bottle holder4is kept in upper position by the spring means3. At the upper part of housing2, there are heating element6and lid5.

In lid5, there is a plug7with an air outlet channel10for allowing the air to flow out during pressing.

In use, the bottle15to be compacted is placed into the bottle holder4, and pressed down together with it until impacting on the base1. With screwing of the lid5into the heating element6, the bottle is fixed, and then the plug7is sealed in the mouth-piece of the bottle. After starting the heating, spring means3presses the bottle upwards, and as the plastic melts in thin layers, it is compressed continuously to a bellow-like object until the compacting process ends by pressing the neck- and mouth-piece into the middle of the agglomerate.

FIG. 2shows the plug7in lid5. A threaded adjusting sleeve9and a ball valve8are arranged in the air outlet channel10of plug7for adjusting the free cross section of channel10. Setting the appropriate spring force in ball valve8may be carried out by means of sleeve9so that it is drawn upwards or downwards by a screwdriver thereby controlling the amount and/or flow rate of the air.

Sleeve9is screwed into a tube11with a threaded section12at the upper end. In this way, tube11can be raised and lowered by turning the plug7. When raised, an elastic sleeve14between an outer flange of the tube11and a bush13is compressed and, at the same time, its diameter increases. Thus, the mouth piece of the bottle15to be compacted is sealed. After this, air can flow out only through the air outlet channel10, controlled by ball valve8.

Melting of a short section of the bottle15is performed by heating element6shown inFIG. 3, with reference to another embodiment of the invention. The height of heating element6is preferably smaller than 60 mm, in order to keep small the height of the section melted at once, thus making compacting uniform and regular.

The height of the heating element6can also be larger than 60 mm, in order to ensure an increased heating potential, but than only a section of it (preferably smaller than 60 mm) is used for direct melting of the bottle. In this case, bush13of the plug7seen inFIG. 2is coupled to the lid5by an external thread to enable lowering the bottle15with respect to the heating element6in the lid5. In this position, a section of the bottle15smaller than 60 mm is heated only.

In the embodiment shown inFIG. 3, lid5is movable on guide bars16, and compacting power is gained from the weight of the lid. As a result, the bottle15is folded gradually in narrow bands, while air leaves through the air outlet channel10of the plug7in a controlled manner.

FIG. 4shows an embodiment in which the bottle compacted by the weight of the lid (5) can be further compacted by mechanical means. For this additional compacting a gear rim18is turned by means of a lever17on a gear rack19fastened to the lid5. In this way, the agglomerate of the bottle15is further compacted before it cools down. Though the compression in the examples shown above was provided by the weight of the lid, many other possible embodiments like spindles driven by electric motors can also be used for compacting the bottles.

It is to be noted that the above non limiting examples shown in the disclosure only illustrate the invention, it is obvious that a skilled person can make other variants without going beyond the scope of the claims enclosed. In these variants compacting can take place by any means of, the apparatus may be closed, or open like the one shown, and the lid may also have many different embodiments.

The basic advantage of the device according to the invention is that, to the contrary of most known devices, compacting starts at the neck piece of the bottle, and narrow melted bands are produced during compaction. Moreover, the air flow-out can also be controlled to maintain optimal conditions for compacting. Due to these factors, the agglomerate has a regular shape and the smallest possible size, since the narrower sections disappear in the bellows-like folded parts. Thereby—as is shown in FIG.5—the volume of the waste is significantly reduced as compared to the state of art. Furthermore, as it provides a simple and inexpensive way for compacting the bottles, the number of thrown away bottles loading the environment will also probably be reduced.