The present invention relates to a method of opening packs by pressure, in particular a method of opening non-hermetic cigarette packs or hermetic packs. The use of the expression "packs" herein means both individual packs and multi-packages containing a plurality of individual packs.

The cigarette packs as well as hermetically sealed packs containing any products, e.g. food products are opened in order to reclaim the product contained therein and the packaging material .

Prior art

In US 5,086,790 a method is disclosed of reclaiming tobacco from the cigarettes contained in closed soft packs, so called not rigid packs. In the described method the packs are conveyed successively to several locations in order first to be pierced by needles having air inlet holes providing compressed air into the packs and causing their expansion. Then the packs are conveyed to a next location where the end panels of the packs are cut off. This method requires careful and proper alignment of the packs at the successive locations. Moreover, cutting the packs always involves undesirable formation of tobacco and paper dust or particles.

A disadvantage of the above described method also consists in that it may not be used for the packs that are not sealed as they are difficult to be effectively expanded. Moreover, the piercing of the packs may also cause piercing of the cigarettes contained therein. This in turn may cause comminution of the tobacco that is afterwards removed from these cigarettes which is also disadvantageous.

The method according to the invention relates to opening non-hermetic packs by pressure, in particular non-hermetic cigarette packs. The method is characterized in that at least one pack is located in a pressure chamber, the pressure inside the said chamber and inside the said pack being subsequently increased beyond the ambient pressure, after which the chamber is abruptly decompressed so that the pack is disrupted as a result of a momentary difference between the pressure inside the chamber surrounding the pack and the pressure inside the pack.

Preferably, the pressure inside the said chamber is increased up to about 1,5 bar, more preferably above about 10 bar .

The chamber is preferably decompressed over a period of time shorter than about 0,3 s, preferably shorter than about 0,1 s.

The chamber is preferably decompressed by means of a quick release valve.

The pressure chamber may be filled with compressed gas.

Preferably, the pressure chamber is provided with at least one movable means for increasing the pressure inside the chamber .

The movable means may be a reciprocating piston movable within a chamber.

Optionally, the movable means may be constituted by vanes rotatable within a pressure chamber that is enclosed by two cylindrical casings which are not co-axial.

The method according to another aspect of the invention relates to opening hermetic packs by pressure, characterized in that at least one pack is located in a pressure chamber, the pack being unsealed prior to or after having been located in the said chamber, the pressure inside the said chamber and inside the said pack being subsequently increased beyond the ambient pressure, after which the chamber is abruptly decompressed so that the pack is disrupted as a result of a momentary difference between the pressure inside the chamber surrounding the pack and the pressure inside the pack.

Preferably, the pressure inside the said chamber is increased up to about 1,5 bar, more preferably above about 10 bar .

The chamber is preferably decompressed over a period of time shorter than about 0,3 s, preferably shorter than about 0,1 s. In this aspect of the invention the pack is preferably unsealed by piercing or an incision by means of a sharp edge.

The chamber is preferably decompressed by means of a quick release valve.

The pressure chamber may be filled with compressed gas.

Preferably, the pressure chamber is provided with at least one movable means for increasing the pressure inside the chamber .

The movable means may be a reciprocating piston movable within a chamber.

Optionally, the movable means may be constituted by vanes rotatable within a pressure chamber that is enclosed by two cylindrical casings which are not co-axial.

The advantages of the method according to the invention are the following:

• it may be used both for opening packs having the quality of a ready product i.e. non-deformed packs with undamaged packaging, and for damaged, e.g. collapsed packs;

• the method does not require the packs to be delivered in an orderly way; neither does it require conveying the packs from one location to another;

• there is no need to cut the packaging which impends cutting of the cigarettes; therefore no packaging material dust or particles formation is involved;

• the method may be used for opening packages having different shapes, both individual packs and multipacks.

The method of the invention is illustrated in the appended drawing, in which: fig. 1 presents a scheme of operation of a method according to the invention when used for opening non- hermetic packs; fig. 2a and fig. 2b present two exemplary schemes of operation of a method when used for opening hermetic packs; fig. 3 presents a pressure chamber with a piston; fig. 3a and fig. 3b present two exemplary schemes of operation of the method when using a chamber provided with a piston for opening hermetic packs; fig. 4 presents a pressure chamber provided with rotatable vanes; fig. 4a and 4b present two exemplary schemes of operation of the method when using a chamber provided with rotatable vanes for opening hermetic packs.

Fig. 1 shows an example of a production waste pack 1 which is located in a pressure chamber 2. The chamber is supplied with highly compressed gas e.g. coming from a compressor 3. The chamber should be sufficiently gas-tight so as to endure a suitably increased pressure until the decompression i.e. until a valve is activated. Considering that the pack 1 is not hermetically sealed, the compressed gas enters into the inside of the pack through gaps in the packaging. Consequently the pressure inside the pack grows and reaches the level of the pressure inside the chamber. Upon establishing (by means of a conventional manometer 4) that the pressure inside the chamber has reached the required level, i.e. at least above 1,5 bar and preferably above 10 bar, the chamber is decompressed by means of quick-release valves 5. The period of time over which the chamber is decompressed is less than 0,3 s. Advantageously, this time may be even less than 0,1 s. At the moment of the decompression of the chamber the difference between the pressure of the operational gas (e. g. air) inside the pack and outside it (meaning between the outside and the inside of the pack) grows abruptly. As a consequence of this pressure difference a force is generated acting on the pack which causes it to be opened or disrupted. The quick-release valves 5 that may be used in the embodiment of the invention are for example the conventional Herion or Festo valves.

The method may be used in particular for opening cigarette packs, as well as other packages of similar type, e.g. cheese, macaroni, chips etc., both individual and multipacks. More than one pack may also be located in the chamber.

Fig. 2a shows a similar scheme to that shown in fig. 1, but related to a method of an embodiment of the invention when used for opening hermetically sealed packs. In this case, prior to increasing the pressure in the a chamber and the subsequent abrupt decompression, the pack must be initially unsealed. The unsealing may be performed before the pack has been located in the pressure chamber (fig. 2a) or inside the chamber (fig. 2b), by piercing or a slight incision by means of a sharp edge, or the blades of an element 6. The other stages of the method presented schematically in fig. 2 are identical as those described with reference to fig. 1.

Fig. 3 presents the pressure chamber equipped with a piston 7 designed for reciprocating movement within and along the cylinder 8. After a pack has been delivered, the cylinder 8 is lowered in order to close the chamber and then the piston 7 is activated to move downward causing the pressure within the chamber to increase. A quick withdrawal of the cylinder 8 and the piston 7 results in decompression of the chamber and opening the pack 1. It is also possible to use a quick-release valve located in the wall of the cylinder 8 or in its bottom. As shown in fig. 3a and 3b and similarly to the example shown in fig. 2, the unsealing may be performed prior introduction of the pack into the pressure chamber or else in the chamber, by piercing or a slight incision by means of a sharp edge or the blades of the element 6.

Fig. 4 presents another example of the pressure chamber. Rotatable vanes 9 and the cylindrical surfaces 10 and 11 enclose a chamber in which the packs 1 are located. During the rotational movement of the vanes 9 the gas within is compressed. Use of a quick-release valve located on the surface 10 enables decompression of the chamber. As shown in fig. 4a and 4b, the same as in the example shown in fig. 2, the unsealing may be performed prior to the introduction of the pack into the pressure chamber or else in the chamber, by piercing or a slight incision by means of a sharp edge or the blades of the element 6.

The essential parameters of the method are: the pressure difference before the decompression and the speed of pressure equalization. The higher is the pressure difference hat was generated, the easier it is to disrupt the pack. On the other hand, the shorter is the time in which the pressures are equalized, the easier it is to disrupt the pack. Similar results may be achieved in terms of opening packs with a substantial pressure difference combined with a slow pressure equalization, and with a small pressure difference combined with a very short time of the pressure equalization. The packs may be opened according to the invention by decompression in the air or any other gas .

Table 1 below shows exemplary values of the pressures reached in the pressure chamber with their corresponding times of decompression as well as the respective results achieved for the cigarette packs dealt with by the method according to the invention .

Table 1

pack pack

Example 7 - a 10 0,4 No substantially disruption deformed pack

Example 8 - a 10 0,1 Disruption substantially of the deformed pack pack