Closed cardtridge with zones of lesser thickness

The invention relates to a closed cartridge, intended for extracted under pressure, containing a substance for the preparing a beverage, comprising a cup with a bottom and a lateral wall having substantially the shape of a inverted truncated cone and a circular rim diameter top to the bottom, and a welded seal around the perimeter of rim of the cup, the bottom of the cup having of the zones of reduced thickness intended to promote the opening of the cartridge during extraction.

EP 521'510 already relates to packaging form closed rigid cartridge containing a substance for the preparation of a beverage and comprising zones of lesser thickness. The disadvantage of this cartridge is that it requires, during extraction, the presence, under the lower face having zones of reduced thickness, of projecting elements. The provision of these elements Key has two drawbacks: first, this system increases the price and secondly, the points are blunted and it is compulsory to monitor the effectiveness of the time.

The object of the present invention is to develop a cartridge having weakened zones so it can be extracted without any protrusion.

The invention relates to a sealed cartridge according to the preamble of claim 1 based on EP-A-0521520 wherein the cup is aluminum or an alloy based on aluminum and zones of reduced thickness are produced by shearing and are in the form of circular arcs concentric of the same radius of circular arcs concentric with different radii, of a spiral, substantially sinusoidal sections or of radial segments.

By an aluminum alloy, is meant in the present description a mixture comprising at least 90% aluminum and a second metal component selected from the group consisting of iron, silicon, manganese, magnesium, chromium, copper, zinc and others.

The cartridge is filled with a substance for the preparing a drink. This substance is preferably roasted and ground coffee, but may also be tea, soluble coffee, a mixture of ground coffee and instant coffee, a chocolate product or any other substance dried edible.

The advantage of having such a cartridge is that the its place in the cartridge holder provided with a support having apertures for permitting the flow of coffee, and when extracting the simple fact of having a rise in pressure in the cartridge permits opening in the zones of reduced thickness. It is understood These thinner areas must have a specific geometry and, for the material, must have adequate residual thickness. We have found during tests that happen to good extraction with zones of reduced thickness having a thickness approximately half that of departure. It is not not at all helpful to have a filter inside the cartridge, the opening along lines weakening is such that it ensures that functionality. There is a coffee grounds held by a controlled opening of the cartridge.

It is important that the weakening zones are created by shearing and not by punching.

The cover should be soft and slightly stretchy for facilitate the perforation. The cover has a thickness less than that of the cup, for example of between 20 and 60 microns.

The cup must have a certain rigidity, by example during handling by the consumer. She has therefore a thickness of between 50 and 150 microns, more preferably between 70 and 100 microns.

It is understood that there must be a cartridge holder on the bottom of which lies the provided face areas thinner: this support is mandatory for control the opening so that the function of filter is busy at the opening of the said cartridge.

Preferably, the cartridge contains coffee roasted and ground. The coffee is disposed in the cartridge is as such or packed or compacted. Packed by means a compression under a pressure of the order of a few hundreds of kilograms. Compacted by a means compression under a pressure of the order of a few tons. Coffee cartridge is preferably packed.

To facilitate the opening of the cartridge, may be provided of the zones of reduced thickness having thicknesses variable along said regions: for example, it can provide a residual thickness of 40 microns which varies up to 60 microns. The opening is first made on the area 40 microns and continue along the line to higher thickness. This also allows self-regulation the extraction pressure.

The second possibility to facilitate the opening is anticipate the start of a zone of lesser thickness starting primer, eg by a cut with residual thickness of 40 microns, while the rest of the area is 50 microns.

In a concrete embodiment, the closed cartridge according to the invention is made of a cup of an alloy aluminum having a thickness of about 85 microns and having zones of reduced thickness in the form concentric arcs of the same thickness to radius range between 40 and 50 microns. If operating with a coffee machine amount to 12 bar, we get to extract a cup of 120 ml in 50 seconds without any grounds pass.

The following description is made with reference to drawings, in which<sl><li>Fig. 1 is a schematic median section of a cartridge according to the invention,</li><li>Fig. 2 is a section AA of Figure 1,</li><li>Fig. 3, 4, 5 and 6 are sections similar to that of Figure 2 but showing different geometries of zones of reduced thickness and</li><li>Fig. 7 is a section on BB to the location of a point thinner.</li></sl>

Referring to Figures 1 and 2, the cartridge comprises a cup (1) consisting of a bottom (2), a wall side (3) and a flange (4) and a lid (5). The cup and the lid are made of an alloy aluminum, the cup having a thickness of 85 microns and the cap 60 microns. The lid is heat on the rim (4) of the cup. The bottom (2) of the cup has three zones (6) of reduced thickness under the form of circular arcs. As already mentioned above, these areas are obtained by shearing using presses stamping. The cartridge contains the ground coffee roasted (7). During the extraction, the opening areas (6) allows the coffee extract to pass, but guarantees also good retention of the coffee grounds. The thickness remaining in the areas (6) is 40 microns.

As shown in Figure 3, it is also possible of the zones of reduced thickness on circular arcs arranged at different distances from the bottom center (8) of the cup. There was thus areas (9) and areas (10). The advantage of this arrangement lies in the fact that at extraction, it is primarily the areas closest to the center, namely (10) will open.

In the case of Figure 4, has a bottom (11) having a zone (12) in a spiral shape.

5 shows a bottom (13) of the cup having zones of reduced thickness (14) of substantially sinusoidal.

6 shows a bottom (16) of the cup having zones of reduced thickness (17) in the form of segments Radial.

Figure 7 finally shows an enlargement cutting the thinner spot obtained by shear. As already mentioned above, the portion (15) has a residual thickness of 40 microns. The distance A is between 0.2 and 1 mm.

It has according to the invention a cartridge design relatively simple to extract with a cartridge holder specific design and for prepare an espresso-type coffee, that is to say with a pressure rise of about 10 bar.