EP0521510B1 - Rigid coffee cartridge and method of manufacturing the same - Google Patents

Abstract

The packaging is in the form of a cartridge containing a substance for making a drink. The cartridge has a body (1) of frustoconical inverted frustoconical or hemispherical shape and a membrane (4) acting as a cover. The membrane or the bottom of the body of the cartridge comprises zones of reduced thickness (3) enabling the cartridge to be opened during extraction by a fluid under pressure while directing the flow of fluid through the bed of substance. The cartridge is available as different variants suitable for various types of espresso machines. <IMAGE>

Description

The invention relates to a packaging in the form of a closed rigid cartridge for making a drink suitable for pressurized fluid extraction machines.

The use of cartridges for the preparation of a drink, especially in the field of espresso type coffees extracted under pressure, is motivated by several reasons: hygiene, optimal conservation of coffee, ease of use, better control of coffee quality obtained and good reproducibility of the extraction conditions. Among all the cartridges available, only the closed cartridges, which open under the effect of the water pressure injected, meet the requirements set out above. These cartridges are distinguished by their opening system. Furthermore, they are substantially impermeable to moisture and preferably to oxygen.

That which is the subject of patent CH-A-605,293, entirely of aluminum, has, at its base with a diameter greater than that of its upper face, a membrane provided with a weakening line, preferably tearing under the pressure effect. This solution has the disadvantage of increasing the complexity and the price of the cartridge because the materials used must be treated very precisely so that the opening is correct and reproducible. In addition, the cartridge has a thick filter to retain the coffee grounds.

Another disadvantage of this cartridge is that being of reverse frustoconical shape, it cannot be adapted to standard type espresso machines and therefore requires a specifically designed extraction machine.

Another cartridge is designed to be used according to a process in which, initially, mechanical zones of weakness are created in the lower membrane, then, in a second step, the capsule is opened under the action of water pressure injected by rupture of weakened areas.
Such a method described in patents FR-A-1537031 and FR-A-2033190, has many disadvantages.

It is first of all complex to produce because the upper and lower faces of the cavity of the device intended to receive the capsule are provided with a multitude of projections and holes.

In addition, this process can not be reliable and reproducible, because it is impossible to achieve under the effect of water pressure all the desired openings. In fact, as soon as one or more openings have been obtained, the pressure drops in the capsule since the liquid can flow.

Consequently, the number and the position of the openings are random. This situation can lead to improper extraction of the substance bed because, the filter being pressed against the underside, the drainage of the latter is not ensured over the entire surface. The extraction is incomplete and heterogeneous due to the existence of zones with preferential passages and poorly irrigated and drained zones.

In addition, such a process is not hygienic. Indeed, given the multitude of orifices for the passage of water and the high temperature of the device, deposits of organic matter which are difficult to remove must inevitably be produced.

Finally, this process can be sensitive to clogging because the successive deposits of organic matter in the multitude of small orifices can contribute to a progressive obstruction of these. Under these conditions, the quality and regularity of the extractions will be even more affected.

Finally, this process is used with a cartridge containing a powdery or liquid base substance. In the case of coffee, it can only be a soluble coffee to be dissolved by water or a concentrated liquid coffee to be diluted by water. This process and this cartridge cannot be used in the case of freshly ground coffee.

Patent CH-A-458099 relates to an installation for the preparation of a drink in which a cartridge is extracted under pressure. The cartridge which may contain ground coffee consists of two rigid sheets of plastic or aluminum perforated and welded together surrounding a porous envelope intended to contain the substance to be extracted, the underside of which is covered with a thin film of material. thermoplastic which melts in the presence of the hot extraction liquid.

Document US-A-2,936,695 on which the preamble of claim 1 is based relates to an infusion device comprising openings covered with a concentrated solution of glucose which dissolves during the passage of the extraction water.

The object of the present invention is to produce a closed cartridge, of frustoconical, frustoconical or hemispherical arrangement, opening under pressure to let the extract pass and which can be extracted in conventional espresso machines by means of a simple adaptation device .

The packaging according to the invention consists of a body and a membrane having a weakened zone, substantially impermeable to humidity and in particular to oxygen and in which the body is frustoconical, inverted frustoconical or hemispherical, of rounded section and provided with a rim and the membrane constitutes the seal of the cartridge fixed to the rim of said body. It is characterized in that the membrane or the flat face of the body itself comprises zones of reduced thickness intended to favor the opening of the cartridge for the passage of the extract under the effect of the fluid pressure and preferably tearing under the effect of the pressure of the fluid during the preparation of the beverage.

According to the quality of impermeability of the material to oxygen, the cartridge can be wrapped as it is or possibly overwrapped in sachets which are themselves leaktight with oxygen and allowing a conservation of 6 to 12 months. In the latter case, the cartridges can be grouped, for example in units of 2 to 10, because, being closed, they have by themselves a shelf life of a few days, for example from 2 to 15 days, once the open sachet.

The cartridge consists of two parts, a body and a membrane. The body is frustoconical, inverted frustoconical or hemispherical. The body section is rounded, that is, it can be circular, oval or polygonal with rounded edges.

Thinner areas can be in the membrane or in the flat face of the body.

The cartridge according to the invention can be extracted with the device comprising a grid which is the subject of European patent application No. 91107462. The cartridge can also be extracted in a conventional espresso type coffee machine using a specific adapter as described in the European patent applications filed on the same day as the present application by the applicant under Nos 91111210, 91111211 and 91111212.

The extraction devices, subject of these requests for patent, allow to extract in good conditions this simplified cartridge. The cartridge opens automatically in the device and after use, can be removed easily and completely with a minimum of waste marc or packaging material.

During extraction, the underside deforms, then tears at the location of the zones of reduced thickness in contact with the perforating tool, for example projecting elements, reaching its breaking tension under the effect of fluid pressure, for example air and water. Coffee extraction can then take place. This lower face has undergone, during manufacture, a preliminary treatment resulting in zones of reduced thickness of the material capable of reaching the breaking tension, in the extraction device, without requiring too great an elongation, despite its plastic nature. These thinner zones are preferably very numerous and distributed uniformly over the entire face.

They can form straight dotted lines made up of lines, for example from 2 to 10 mm in length and from a few µm to a few mm in width.

They can be lines in concentric arcs, distributed on circles of variable diameter. In this case, the extraction device, intended for the use of these cartridges, may comprise protruding elements on the flow grid, the arrangement of which corresponds to that of these arcs. Thus, the cartridge and the thinner areas are perfectly placed with respect to the projecting elements of the grid intended to promote their opening.

These thinner zones can be obtained by local absence of an upper layer or part of an upper layer of the material constituting the lower wall of the cartridge.

Unlike patent FR 2033190, the extraction of the cartridge is carried out under pressure, which means that the maximum pressure of the extraction fluid is not reached when the cartridge is opened, but later during the extraction when the pressure drop across the coffee bed has reached its maximum.
In addition, the thinner areas in the lower face, which are produced only during the manufacture of the cartridge, are not obtained by stamping the material but by separate, more reliable processes, that is to say freed tolerance issues.

The treatment of the lower face is all the more justified in the case where the shape of the cartridge is frustoconical reverse, because then this face being of a thickness close to that of the truncated cone, that is to say d 'a thickness large enough for the part to be rigid, its tearing could not normally be obtained without very great elongation, incompatible with the pressures and water temperatures employed.
In the case of a frustoconical cartridge, the situation is less critical and the membrane, constituting the lower face, can be of a thickness much more reduced than that of the body, since the membrane contributes little to the rigidity of the cartridge in this case and the pressure is exerted on a larger surface.

The invention further relates to a method of manufacturing the cartridge, in which the body of the cartridge is thermoformed or stamped in a first film, the body thus formed is filled with a pulverulent composition for beverage under a stream of inert gas, then the membrane formed from a second film is sealed on the body of the cartridge.
The process is characterized by the fact that thinner areas in the first film or in the second film prior to filling the cartridge.

• la figure 1 est une coupe schématique médiane d'une cartouche de forme tronconique inversée,
• la figure 2 est une coupe selon A-A de la figure 1,
• les figures 3 et 4 sont des coupes schématiques médianes de différentes cartouches de forme tronconique et
• les figures 5,6,7 et 8 sont des coupes partielles montrant des détails des zones de moindre épaisseur créées dans les cartouches.

A la figure 1, le corps 1 de la cartouche comporte une face plane 2 pourvue de zones de moindre épaisseur 3. La cartouche une fois remplie de composition pulvérulente pour boisson (non représentée) est fermée par un opercule 4 qui constitue la membrane venant s'appliquer sur le rebord 5 du corps. Le corps 1 est thermoformé ou injecté, de préférence à partir d'un film de 100 à 500 µm, en polyester, polyamide, polyoléfine, par exemple en complexe polyéthylènetéréphtalate d'épaisseur 20 µm lié avec un polypropylène perforé ou tissé ou non tissé, un polyéthylène téréphtalate perforé ou tissé ou non tissé ou un polyéthylène perforé. La perforation s'effectue préalablement au laminage du complexe et au formage.
La membrane 4 est composée d'un film, de préférence de polyester, polyamide ou polyoléfine de 10 à 50 µm, par exemple un complexe de polyéthylènetéréphtalate d'épaisseur 12 µm chargé de silice avec un polypropylène, un polyéthylènetéréphtalate ou un polyéthylène. La membrane, présente une surface en contact avec le corps de même matériau ou de matériau thermoscellable avec celui du corps.The invention will be better understood with the aid of the description below relating to different variants of cartridges given by way of example with reference to the appended drawings in which:

• FIG. 1 is a schematic median section of a cartridge of inverted frustoconical shape,
• FIG. 2 is a section along AA of FIG. 1,
• Figures 3 and 4 are schematic median sections of different frustoconical cartridges and
• Figures 5,6,7 and 8 are partial sections showing details of the thinner areas created in the cartridges.

In FIG. 1, the body 1 of the cartridge has a flat face 2 provided with zones of reduced thickness 3. The cartridge once filled with powdery composition for beverage (not shown) is closed by a cover 4 which constitutes the membrane coming from 'apply to edge 5 of the body. The body 1 is thermoformed or injected, preferably from a film of 100 to 500 μm, made of polyester, polyamide, polyolefin, for example of polyethylene terephthalate complex 20 μm thick bonded with a perforated or woven or non-woven polypropylene, a perforated or woven or nonwoven polyethylene terephthalate or a perforated polyethylene. The perforation is carried out before the laminating of the complex and the forming.
The membrane 4 is composed of a film, preferably of polyester, polyamide or polyolefin of 10 to 50 μm, for example a complex of polyethylene terephthalate of thickness 12 μm loaded with silica with a polypropylene, a polyethylene terephthalate or a polyethylene. The membrane has a surface in contact with the body of the same material or of heat-sealable material with that of the body.

In FIG. 2, we can see how the thinner areas 3 are distributed on the flat face 2 of the body 1.

FIG. 3 relates to a variant of cartridge of inverted frustoconical shape. In this, the body is formed by thermoforming a polyester film, polyester / polyolefin complex or cardboard, the latter being for example of 200-300 g / m2 grammage and bonded to a polyester layer.

In a preferred version which gives the pulverulent composition for beverage complete protection against oxidation, the body is formed from a thin barrier film, preferably from 5 to 30 μm thick, of polyvinylidene chloride or of copolymer. of ethylene and vinyl alcohol, sandwiched between two layers of polyolefin, for example a multi-layer film of polypropylene / copolymer of ethylene and vinyl alcohol / polypropylene, polyethylene / copolymer of ethylene and vinyl alcohol / polyethylene, for example from 100 to 500 μm thick. The thin barrier film may alternatively be a thin layer of polyester, for example from 10 to 20 μm loaded with silica or metallized. The body can also be made of cardboard, for example weighing 200-300 g / m2, linked to a complex of ethylene-vinyl alcohol copolymer with a polyolefin or a polyester.

The membrane consists of a complex film, for example of polyester loaded with a layer of silica or metallized, for example of 10-20 μm with a layer of polyolefin, optionally perforated or woven or nonwoven or of polyester, if necessary perforated or woven or nonwoven.

In FIG. 4, the membrane 4 is provided with thinner zones 3.

In FIGS. 5 and 6, the thinner zones 3 can be created by any means of perforating or cutting the wall 8, for example using a tool provided with a multitude of small sharp blades, for example 2 to 10 mm in length, and thereby form slits throughout the thickness of the material. This operation can take place prior to the forming of the capsule or the application of the membrane, but is preferably carried out after forming for the perforation of the bottom of the body. After this perforation, a heated tool can be applied to the external surface of the perforated film so as to close over a small thickness 9, for example from 5 to 20 μm, the slots initially created as shown in FIG. 5. As a variant of this fusion surface shown in Figure 6, one can apply all around the perforated cartridge a plastic film (10, fig.6) very thin for example from 5 to 20 microns in heat shrinkable thickness. In this latter embodiment, the material of the cartridge can be aluminum and the thin film 10 can be aluminized.

In FIG. 7, the body of the cartridge or the membrane is thermoformed in such a way that the lower wall of this cartridge has a ridged underside but still of a uniform thickness between a punch and a ridged matrix to create ribs, then the blank of the cartridge is placed in an identical matrix but with a heated punch also striated and whose ribs correspond to those of the matrix. The pressure of the punch against the die causes a significant reduction in the thickness of the material such as 3 in the areas where the ribs of the tools correspond. In the grooves between the ribs, the wall retains its initial thickness such as 11.

In the representation of figure 8, the film multilayer comprises thick and resistant structure layers 12 which have been locally torn or cut or which are in the form of a fabric or a nonwoven structure of plastic material. These structural layers are linked to a thin layer 13 impermeable to oxygen.

In all the versions of cartridges presented in this text, the cartridge according to the invention can be of variable size according to the volume of drink that one wishes to prepare. For example, the dose of coffee contained can vary between 5 and 20 g, the diameter of the cartridge is between 2.5 and 7 cm and the thickness of the coffee bed between 10 and 25 mm.

The cartridge is filled with a pulverulent composition for the preparation of a drink. This substance is preferably roasted and ground coffee, but can also be tea, soluble coffee, a mixture of ground coffee and soluble coffee or a chocolate product.

The cartridge is adapted to the extraction device having a tool for perforating the upper and lower faces of the cartridge during extraction. The thinner areas are located on the underside (for example as shown in fig. 1 and 3), which facilitates perforation. In all cases, the extraction fluid will be directed in a vertical flow so as to pass through the entire bed of pulverulent composition without risking the creation of lateral flow flow.

In the case where it is desired to completely eliminate the risks of dispersion of the marc after the extraction, a layer of filter paper or of woven or nonwoven plastic fibers can be interposed between the substance to be extracted and the lower internal wall of the cartridge (as shown in fig. 3, number 14).

This layer may or may not be bonded to said wall.

Claims (7)

1. Pack in the form of a closed rigid cartridge containing a substance for preparing a beverage suitable for extraction machines operating by a fluid under pressure, consisting of a body and a membrane having a weakened zone, substantially impermeable to moisture and, in particular, oxygen, in which the body is in the form of a frustum, an inverted frustum or a hemisphere, with a rounded cross-section and provided with a rim, and the membrane forms the cover of the cartridge fixed to the rim of the said body, and in that the membrane or flat face of the body itself comprises zones of reduced thickness intended to promote opening of the cartridge so that the extract can pass under the effect of fluid pressure, and tears preferentially under the effect of fluid pressure as the beverage is prepared.
2. Pack according to claim 1, characterized in that the lower face, namely the membrane if the body is a frustum or hemispherical, and the flat face of the body if it is an inverted frustum, comprises zones of reduced thickness created by cutting slits through the said face, forming a thin film of plastic material on the outside of the face by heat treatment or, where the body is an inverted frustum, by reducing the thickness of the material in certain zones of the face by stamping.
3. Pack according to claim 1, characterized in that the body and the membrane are made of a multilayer film which is thermoformable and heat-sealable to itself, the thick structural layer(s) of which has/have been locally torn or cut or are in the form of a woven cloth of synthetic material or blended non-woven fibres of synthetic material and in that the structural layer(s) is/are bonded to a thin layer of oxygen-impermeable plastic material.
4. Pack according to one of claims 1 to 3, characterized in that it additionally comprises an interposed layer of filter paper or woven or non-woven synthetic fibres between the substance to be extracted and the lower inner wall of the cartridge.
5. Process for producing a pack according to claim 1, in which the body of the cartridge is thermoformed or stamped from a first film, the body thus formed is filled with a powdered composition for a beverage in a stream of inert gas, after which the membrane formed from a second film is sealed to the body of the cartridge, characterized in that zones of reduced thickness are formed in the first film or the second film before filling the cartridge.
6. Process according to claim 5, characterized in that the zones of reduced thickness are formed in the part of the first film forming the base of the cartridge before forming the cartridge in the case where the body is an inverted frustum or in part of the second film forming the membrane before it is applied to the body in the case where the body is a frustum or hemispherical, by tearing or piercing to form slits, after which the outer face of the base of the cartridge or the membrane is covered with a thin oxygen-impermeable plastic film or the outer surface of the said face is heat-treated to re-close the slits initially formed over a minimal thickness.
7. Process according to claim 5, characterized in that the zones of reduced thickness are formed in the lower face of the body in the case where the body is an inverted frustum by reducing the thickness of the material in certain areas of the face by stamping as the body is formed.

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