Capsule for beverage preparation

This application is the U.S. national phase of International Application No. PCT/IB2009/051534 filed 13 Apr. 2009, which designated the U.S. and claims priority to PCT/IB2008/051412 filed 14 Apr. 2008, the entire contents of each of which are hereby incorporated by reference.

The field of the present invention is that of the preparation of beverages, based for example on coffee, by brewing a concentrated serving, of ground coffee for example, contained in a capsule. It relates more particularly to the servings used for this purpose and to the devices using such servings.

Capsules and machines operating on the abovementioned principle have existed for many decades.

U.S. Pat. Nos. 2,899,886, 2,968,560, 3,403,617 and 3,607,297 describe devices in which the capsule is initially perforated at several points before hot water is passed through it under pressure.

The capsule disclosed in patent CH 605 293 or in patent EP 0 242 556 B1 has a membrane at the bottom. Hot water under pressure is initially introduced into the top of the capsule. This causes a swelling of the capsule, principally of the membrane. Above a certain pressure the membrane tears, allowing a water-coffee mixture to flow out.

Other capsules provided with a membrane are disclosed in the following patent documents: EP 0 468 079 A, EP 0 806 373 A, EP 0 554 469 A.

Although most of the hot water introduced under pressure flows into and through the capsule, some flows out of it, down the outer face of the side wall. In theory, these leaks should not get further than the base of the side wall, because here the capsule cage is in contact with the lip.

Unfortunately this is not the case with prior art capsules. Some liquid can therefore escape from the machine and/or mix with the liquid that has passed through the interior of the capsule. In this latter scenario, the quality of the coffee is reduced.

There is therefore a need to reduce, and if possible eliminate, leaks of liquid flowing down the outer face of the side wall of the capsule.

One of the objects of the present invention is to improve upon prior art capsules.

Another object is to solve the seal problem described in the previous section.

More specifically, the invention seeks in particular to ensure that the liquid, which should in theory flow only into and through the capsule, does not flow out of it, down the outer side wall of the capsule, further than the contact region between the lip and the capsule cage.

This object, in particular, is achieved with the capsule according to the invention as defined in the main claim, and certain particular embodiments are defined in the dependent claims.

The invention has the advantage that it improves the seal between the lip and the lower part of the capsule cage. Specifically, as the water flows down the outer face of the wall of the capsule and contacts the lip, the lip softens. This allows the capsule cage to press more deeply into the thickness of the lip. The seal at this location is therefore improved.

Any material that behaves as indicated above, that is to say softens, can be used for the purposes of the present invention.

Advantageously it is a biodegradable material.

The invention is described in more detail below by means of examples illustrated in the accompanying figures.

FIG. 1 shows a capsule 1 according to the invention after closure of the cage 4 , but before hot water enters.

FIG. 2 shows the entrance of hot water 7 , principally into the capsule 1 , but also into the space 6 between the outer face of the side wall 2 of the capsule and the inside face of the cage 4 .

FIG. 3 shows the positioning of the cage 4 relative to the lip, following softening of the latter.

According to the invention, the capsule 1 for preparing a beverage, such as coffee, comprises a hollow element designed to contain a serving, of ground coffee for example. The hollow element comprises a side wall 2 , an upper face, a lower face with a discharge membrane, and a lip 3 ; said side wall 2 being continued at its bottom in such a way as to form said lip 3 , the latter being oriented in a plane that intersects said side wall 2 . According to the invention, the lip 3 is formed at least partly of a material that softens when placed in contact with a liquid.

The temperature at which said material softens is preferably above room temperature.

The present invention is not limited to the examples and embodiments described purely by way of illustration. Variations are possible within the scope of the claimed protection, particularly by employing equivalent means.

1 . Capsule

2 . Side wall

3 . Lip

4 . Cage

5 . Bottom of cage

6 . Space between capsule and cage

7 . Water