CAPSULE FOR PREPARING A BEVERAGE

Description

FIELD OF THE INVENTION

The present invention falls within the field of the preparation of beverages, e.g. coffee-based beverages, by extraction of a concentrated portion, e.g. of ground coffee, contained in a capsule. It relates more specifically to the portions used for this purpose and to the devices that use such portions.

PRIOR ART

Capsules and machines operating on the abovementioned principle have been in existence for many decades.

Patents U.S. Pat. No. 2,899,886, U.S. Pat. No. 2,968,560, U.S. Pat. No. 3,403,617 and U.S. Pat. No. 3,607,297 describe devices in which the capsule is first of all perforated at several points, then has water pass through it under pressure.

The capsule described in patent CH 605 293 or in patent EP 0 242 556 B1 comprises a membrane in its lower part. Water under pressure is first of all introduced into the top part of the capsule, after said capsule has been pierced by means of a cutting element (e.g. a blade), and this causes the capsule to swell, mainly in the region of the membrane. Beyond a certain pressure, the membrane tears, thereby allowing a water-coffee mixture to flow out.

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

SUMMARY OF THE INVENTION

The present invention comprises a number of improvements over the capsules of the prior art. Specifically, it relates to a capsule for preparing a beverage, for example coffee, comprising a hollow element intended to contain a portion, e.g. of ground coffee, said hollow element comprising a side wall, a top wall and a bottom wall comprising an extraction membrane; the top wall comprising on its internal face a weakened zone designed to undergo a movement when an external element applies force to it, thus offering a passage via which liquid can flow between the outside and the inside of the capsule.

One of the advantages offered by the present invention lies in the possibility of forming liquid outflow passages of sufficiently wide cross section. That is particularly true of capsules made of a biodegradable material. This material has a tendency to swell in the presence of liquid. If the weakened zone is not of sufficiently wide cross section then the piercing of the capsule by a cutting element will not allow the liquid to flow out sufficiently through the pierced zone.

By providing the capsule according to the invention with a weakened zone of wide cross section, it is possible to guarantee that there will be outflow space.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described in greater detail hereinafter by means of some nonlimiting examples illustrated by the following figures:

FIG. 1 illustrates a first example of a capsule according to the invention

FIG. 2 illustrates an alternative form of the top part of the capsule of FIG. 1

FIG. 3 illustrates another alternative form of the top part of the capsule of FIG. 1

FIG. 4 shows the inside of the capsule of FIG. 1

FIG. 5 illustrates an enlargement of part of the inside of the capsule of FIG. 1

FIG. 6 illustrates a depression on the external face of the side wall

FIG. 7 shows a second example of a capsule according to the invention

FIG. 8 shows a third example of a capsule according to the invention

FIGS. 9 and 10 illustrate the weakened zone positioned on the internal face of the top wall

FIGS. 11 and 12 illustrate the rupturing of the weakened zone.

List of numerical references used in the figures:

• • 1. capsule
  • 2. side wall
  • 3. top wall
  • 4. bottom wall
  • 5. cavity
  • 6. top wall stiffening element
  • 7. side wall stiffening element
  • 8. top edge stiffening element
  • 9. internal protrusion
  • 10. beading
  • 11. weakened zone
  • 12. piercing element

The following features associated with the capsule according to the invention are worthy of particular note:

• a) The top part of the capsule is reinforced by an architecture known as an “exposed beams”, “reinforcing” or “framework” architecture the purpose of which is to reinforce the capsule in its ability to withstand the pressure of the water and at the time of its perforation. It is also possible to obtain a reinforced structure using folds of material. The rigidity may also be reinforced using an architecture of the “exposed beams” or “framework” type which is concave in relation to the capsule (see FIG. 2).

Using this structure, it is possible to reduce the amount of material used, e.g. the amount of biodegradable material, of fine material of the PET or metal type or any other petroleum-derivative-based material.

• b) The inside of the capsule has projecting internal elements or a circumferential rim the purpose of which is to prevent the empty capsules from becoming wedged together before they are filled at the factory. These same projecting elements also provide the capsule with lateral reinforcement (see FIG. 4).
• c) On the outside of the capsule, opposite each projecting element or opposite a circumferential rim, a cavity is created which strengthens the lateral parts of the capsule through a framework effect while at the same time saving on material (see cross section) and in particular allows the use of biodegradable material and fine materials of the PET or metal type or any other petroleum-derived material. The lateral reinforcement of the capsule may also be created by folds of the material (see FIGS. 5-6).
• d) The outer lateral part of the capsule has facets which may extend as far as the vicinity of the bottom part of the capsule or over a certain distance in the heightwise direction. In this alternative form also, it is therefore possible to save on material while at the same time reinforcing the lateral parts of the capsule (see FIGS. 7-8).

To sum up, all the reinforcing systems mentioned hereinabove allow rigidity to be achieved using less material and make it possible to make advantageous use of biodegradable materials or of any other material of the (PET, metal) type, or of any other petroleum- derived material.

The internal top part of the capsule is provided with a beading of material in the region of the elements that pierce the capsule (see FIG. 4).

Rupture initiators are positioned along the side edges of the beading. When a piercing element applies sufficient pressure to the region of the beading, the rupture initiators yield and this has the effect of allowing water to enter the capsule (see FIGS. 9-12).

The invention is not restricted to the examples illustrated.

Any reinforcing structure whatever is conceivable.

For preference, the capsule is made of a biodegradable material.

Advantageously, the biodegradable material may be of plant origin.

According to an alternative form, the material comprises the following components: starch (>70%), fibers, proteins, lipids, glycerin of plant origin, biodegradable resins.

According to another alternative form, the material comprises the following components: starch (>70%), fibers, proteins, lipids, biodegradable resin, inorganic coloring.

Finally, it should be pointed out that the capsule according to the invention can also be used with devices of the state of the art which are equipped with blades for letting water into the capsule.