EP3251976B1 - Capsule for preparing a beverage - Google Patents

Description

The invention relates to a capsule for the production of a beverage according to claim 1. Such capsules are particularly widespread for the preparation of coffee. But they are also used for tea or mixed drinks. Accordingly, when hot water is passed through the capsule, the substance contained in the closed chamber is either extracted, such as coffee powder, or dissolved by the hot water, such as milk powder.

In many capsule systems, the capsules are already opened on the inlet side when they are placed in a beverage preparation machine. Mandrels or knives penetrate a capsule wall or the capsule lid to introduce hot water. On the outlet side, the capsule is opened by the build-up of internal pressure and by the tearing open of a membrane along at least one weakened line.

Already through the DE 27 52 733 A1 a cartridge for the production of a drink has become known, which consists of a dense body made of aluminum sheet, which is closed by a membrane. The membrane has a line of weakness that defines an opening. The membrane is also made of aluminum and the weakening line is not closed in a preferred embodiment, but has the shape of a “C” or a horseshoe.

through the EP 2 891 615 A1 a capsule for the preparation of a drink has also become known, in which the lid of the capsule does not form the outlet side but the inlet side. An outlet nozzle is arranged at the bottom of the capsule, whose bottom entrance is closed with a bursting membrane. The bursting membrane has weakening lines starting from the center in a star shape in order to form an opening that is as uniform as possible when the internal pressure rises.

through the EP 2 616 367 B1 , which discloses a capsule according to the preamble of claim 1, a cartridge for coffee and soluble products for the preparation of a beverage has become known. The cartridge has a tubular container body, the ends of which are closed with a membrane. Each membrane consists of a composite foil made of, for example, aluminum and plastic foil. A large number of small incisions are provided in the plastic film, which, under the action of pressure, form small openings in the membranes.

A disadvantage of the known capsules is that it is difficult or almost impossible to apply weakening lines in relatively thin aluminum foils. However, if the wall thicknesses are too great, a high internal pressure must be built up for the bursting open. It is therefore an object of the invention to avoid the disadvantages of the known and to create a capsule whose bursting membrane can be produced inexpensively, with the bursting behavior being able to be controlled within a large pressure range. According to the invention, this object is achieved with a capsule which has the features in claim 1 .

The capsule comprises a chamber containing at least one substance such as coffee or tea. The preferably closed chamber has an outlet section which, in order to form an outlet opening, is formed by a membrane that ruptures under internal pressure in the chamber. The membrane can directly form the lid or the base of the capsule or it can be arranged inside the capsule. Chamber is in a capsule body arranged or it is formed by this. This capsule body can be closed with a lid, which also consists of a foil made of metal or plastic. The chamber is designed to be essentially liquid-tight and air-tight with respect to the outside atmosphere, so that the substance is protected from environmental influences. Depending on the material of the capsule body, the chamber is also designed to be aroma-tight against the outside atmosphere, so that oxidation by penetrating oxygen is prevented. The capsule body can be made of plastic material or aluminum.

To define the outlet opening, the membrane is provided with at least one weakened zone, in particular with at least one weakened line, the shape of which can vary. Of course, the membrane can also be provided with a plurality of, for example, 2, 3, 4, 5 or more weakening lines, which can also be connected to one another. According to the invention, the membrane consists of a composite foil comprising at least one metal foil and at least one plastic foil, with the weakened zone being arranged only in the plastic foil. The weakened zone can have any geometric layout and can also consist of a combination of surfaces and lines, for example.

The metal foil, for example made of aluminum, remains completely intact and the tearing behavior is determined exclusively by the weakened zone arranged in the plastic foil. Surprisingly, it has been shown that the weakened zone in the plastic film is completely sufficient and that, in the case of a weakened line, the tear in the metal foil follows exactly the weakened line in the plastic film. Thus, relatively thin metal foils can be used, which also with a tear reliably at lower internal pressures. A weakening line in the plastic foil is much easier to apply than in the metal foil.

A membrane that consists of an aluminum foil with a laminated PET (polyethylene terephthalate) layer has proven to be particularly advantageous. Such films are already used in the packaging industry and are available as standard goods. The production costs can be reduced considerably as a result. Other food grade plastics are also conceivable.

In addition, a sealing lacquer for sealing the membrane onto a support structure, in particular onto a support shoulder of the capsule body, can be applied to the side of the aluminum layer facing away from the plastic film or PET layer. In this way, the membrane can easily be installed in the capsule body by means of heat sealing. The support structure below the area covered by the membrane can be configured as desired.

The aluminum layer can have a wall thickness of 6 to 30 μm, preferably 15 μm. Of course, depending on the application, other wall thicknesses are also conceivable.

Optimum results are achieved when the plastic film faces the chamber with the zone of weakness. Depending on the course of the weakened zone, the tearing stress that builds up under internal pressure causes a tear in the film that follows the weakened zone in whole or in part.

If the weakened zone is at least one weakened line, this can run in a straight line or curved or angled. For example, a wavy line or a meandering line would be conceivable. The weakening line can run uninterrupted or an interrupted course would also be conceivable. The uninterrupted course of the weakening line on the outlet section has the advantage that the outlet opening can be better controlled in such a way that the ruptured membrane does not impede the outflow of the beverage.

The outlet section is circular and the weakening line can form a straight line which traverses the outlet section. This creates an elongated tear in the membrane. The membrane is freely stretched, comparable to an eardrum, and bulges outwards in a convex manner when the internal pressure builds up when viewed from the closed chamber.

The outlet section is circular and is supported on the side facing away from the chamber by a preferably circular support structure, with the weakening line forming a chord which intersects the outlet section between the outer circumference and the support structure. As can be seen, the membrane is designed as an annular surface that is supported not only on the outer circumference but also in the center. The weakening line intersects this annular surface as a chord. Of course, it would also be conceivable for the weakening line to intersect the annular surface radially outwards, starting from the center.

Finally, the outlet section is also circular, with the weakening line forming a tangent to the freely stretched area of the membrane. This is conceivable with or without a central support. In such a case, the line of weakness does not cause a weakening in the freely stretched Area of the membrane, but in the immediately adjacent area of attachment to the outer circumference.

In a further embodiment with a circular outlet section and with a preferably circular support structure on the side facing away from the chamber, the weakening line can surround the support structure. The weakening line runs in the free-tensioned area between the support structure and the outer circumference of the outlet section, with the configuration of the weakening line being able to run polygonally, circularly or as any desired curve.

The membrane may be mounted on a preferably circular support shoulder which is formed by the capsule body and which is thus integral with it. Of course, other arrangements of the membrane within the capsule would also be conceivable. For example, the membrane could be attached directly to a circumferential, outwardly directed collar of the capsule body. In certain cases it would even be conceivable that the membrane itself forms part of the capsule body.

The central support structure and the preferably circular support shoulder do not necessarily have to be part of the capsule body, but could also be arranged on a separate component. However, if the membrane is supported and fixed not only at its circular periphery but also at the center, controlling tear behavior at the line of weakness is particularly tricky. The edges of the contact points also influence the tearing behavior of the circularly stretched bursting membrane, because the tearing stress would be greatest there due to the physical conditions without a weakening line. A "punch through" of the central support structure however, the membrane is not desirable because it could impede the drainage of the beverage. This can be reliably prevented by the proposed arrangement of the weakening line.

The at least one weakening line, which preferably forms a straight line, a chord or a tangent, does not necessarily have to be understood as the shortest connection between two points on the membrane. Rather, it means the general orientation or arrangement of the line of weakness in a generalizing sense.

If the beverage made with the capsule is an extract, such as coffee or tea, the solid components must be retained in the chamber. A filter, in particular a filter fleece, a perforated film or a perforated filter plate, can be arranged between the chamber and the membrane. Such filter means are already known in the prior art and are not described in detail here.

Depending on the capsule system and the type of preparation machine, an outlet connection can be arranged on the side of the membrane facing away from the chamber. This makes it possible for the drink to be fed directly from the capsule into a drinking vessel.

Depending on the desired opening behavior, the weakening line can be designed as a zigzag line or as a meander line or as a wavy line. It is also conceivable that several weakened side lines running transversely to the at least one weakened line emanate from it. These can either cross the line of weakness or just abut against it from one side. The proposed variants can be used when tearing open Openings are created in which the edges are reliably prevented from closing again.

In order to create a sufficiently large flow opening, it is particularly advantageous if the membrane tears under an internal pressure in the chamber between 0.5 and 20 bar in the area of the weakening line in such a way that the membrane deforms plastically without restoring properties and that an opening with a clear width of more than 1 mm is formed. The term clear width is to be understood as meaning the distance between the adjacent edges of an opening. An opening that is larger than 1 mm ² overall is particularly advantageous.

The invention also relates to a method for producing a membrane for a capsule according to the invention or for producing such a capsule. In this case, the weakened zone in the plastic film is produced by removal using a laser, in particular by laser cutting. With the help of a laser, the width and depth of the weakened zone can be precisely determined without the metal layer being weakened as a result.

A particularly optimal process results when the composite film is formed as a tape that can be wound up and when a weakening line is first produced, preferably extending in the direction of the tape. Of course, several weakening lines can also be produced next to one another in the strip direction. The strip processed in this way forms a semi-finished product from which the membrane for the capsule is then punched out of the strip and inserted into the capsules. The punching takes place relative to the linear weakening line in such a way that it runs through the membrane at the desired point.

The covering of the unfilled capsules with the prepared tape and the subsequent punching out and insertion of the membrane can take place immediately one after the other in a continuous work process. Alternatively, it is also conceivable for the weakening line to be applied directly at the work station before the punching out and sealing, whether by laser or other aids.

The described production of the membrane from a coilable tape by subsequent punching out and inserting it into the capsule could also be particularly advantageous independently of the configuration of the capsule. The semi-finished products can be produced and stored particularly efficiently and independently of the capsule production. The coiled tapes can be used particularly optimally in an automated manufacturing process for the capsules.

Further individual features and advantages of the invention result from the following description of exemplary embodiments and from the drawings.

Figur 1:

Eine perspektivische Schnittdarstellung durch eine erfindungsgemässe Kapsel mit einer Membran am Boden der Kapsel;

Figur 2:

Eine vergrösserte Teildarstellung auf die Membran der Kapsel gemäss Figur 1;

Figur 3:

Eine schematische Darstellung des Schichtaufbaus einer erfindungsgemässen Membran;

Figuren 4-7:

Schematische Darstellungen mit unterschiedlichem Verlauf der Schwächungslinie auf der linken Seite und des daraus resultierenden Reissverhaltens auf der rechten Seite;

Figuren 8-11:

Schematische Darstellungen von alternativen Ausgestaltungen einer Schwächungslinie.

Show it:

Figure 1:

A perspective sectional view through a capsule according to the invention with a membrane at the bottom of the capsule;

Figure 2:

An enlarged partial view of the membrane of the capsule according to figure 1 ;

Figure 3:

A schematic representation of the layer structure of a membrane according to the invention;

Figures 4-7:

Schematic representations with different course of the weakening line on the left side and the resulting tearing behavior on the right side;

Figures 8-11:

Schematic representations of alternative configurations of a line of weakness.

figure 1 shows a capsule 1, as for example in the WO 2015/124558 A1 is described in more detail. The rotationally symmetrical capsule body 2 has a capsule base 17 and a capsule side wall 18. The capsule body 2 is closed with a cover 19 on a peripheral collar. A peripheral supporting shoulder 12 is formed integrally with the capsule base 17, on which a membrane 6, which is only partially visible, is sealed.

Also formed in one piece with the capsule base 17 is an outlet connector 16, in the center of which an elongate flow element 23 is held. The area of the outlet connector facing the inside of the capsule forms a support structure 13 ( figure 2 ) which is firmly connected to the membrane 6 and supports it.

A cup insert 20 is arranged in the capsule body and snapped in at the bottom with a snap-in connection 24 . The cup insert 20 is supported on the side wall 18 of the capsule by a peripheral collar 21 towards the side of the lid 19 . Coffee powder is included in the cup insert, for example.

The bottom of the cup insert 20 is designed as a hole filter 14 that holds back the coffee grounds during the extraction process. To stiffen the filter base, stiffening ribs 22 are arranged, of which figure 1 one is cut in full length. The cup insert 20 could also be replaced by another insert replaced or it could be omitted altogether when the substance is a soluble product such as powdered milk.

As can be seen, the inside of the capsule body forms a closed chamber 3, the outlet section of which is formed by the membrane 6 already mentioned.

Further details of this arrangement result from figure 2 . The cup insert 20 has been removed here and the membrane 6 sealed onto the peripheral support shoulder 12 is only partially shown, so that the support structure 13 underneath is still partially visible. This inner part of the outlet connector 16 has several outlet slots 15 running in the longitudinal direction of the outlet connector. The central section of the support structure 13 is also provided with slots 15 of this type.

The membrane 6 is provided with a linear weakening line 7 which eccentrically crosses the circular outlet section 4 formed by the membrane. When using the capsule in a preparation machine, the lid 19 is pierced by means of a cannula, after which hot water is pumped into the closed chamber. Under the internal pressure that builds up, the membrane 6 tears along the weakened line 7, as a result of which an outlet opening 5 is formed. The liquid flows through these into the area under the membrane 6 and through the slits 15 into the outlet connection 16.

figure 3 shows schematically the structure of a composite film 8 from which the membrane 6 is made. A plastic film 10, preferably made of PET, is laminated onto a metal foil 9, preferably made of aluminum. On the opposite side can a sealing wax 11 can be applied so that the composite film can be fixed in a simple manner. As shown, the weakened zone designed as a weakened line 7 is only arranged in the plastic film 10 . The weakening line is lasered out of the plastic layer. The width and depth of the weakening line 7 can thus be optimally determined. The weakening line does not necessarily have to penetrate the entire plastic film. The metal foil made of aluminum can have a wall thickness of 15μ, for example. In relation to the total wall thickness of the membrane, the weakened zone could also be made much wider than shown here.

the Figures 4 to 7 show schematically on the left-hand side a composite film 8 designed as a rollable strip, for example as described above. Depending on the size of the membrane to be produced, the film strip has a width b. An endless weakening line 7 is arranged at a distance x from an outer edge of the strip and extends linearly in the longitudinal direction of the film strip. In the band, the subsequently punched membrane 6 is shown schematically and also the basis of figure 2 described peripheral support shoulder 12 and the central support structure 13.

According to figure 4 the weakening line 7 runs as a chord between the surrounding support shoulder 12 and the central support structure 13. As shown on the right-hand side, when the membrane 6 ruptures, an opening 5 is formed in the form of a longitudinal slit, which is delimited on both sides by the surrounding support shoulder. This is a preferred embodiment because the opening behavior can be easily controlled.

In the embodiment according to figure 5 the weakening line runs through the center of the surrounding support shoulder 12 and the central support structure 13. Openings 5a, 5b form in the freely stretched area of the membrane 6. However, the membrane remains firmly connected to the support structure 13.

In the embodiment according to figure 6 forms the weakening line 7 similar to the embodiment according to FIG figure 4 also a tendon, which cuts the membrane in the freely stretched area. However, the chord is far outside in the area of the outer diameter, which means that the points at which the weakening line 7 intersects with the supporting shoulder 12 are close together, as can be seen. As can be seen, the tearing behavior of the membrane thus changes and the tearing stress causes a tear which expands towards the central support structure 13 .

In the embodiment according to figure 7 the weakening line 7 only runs straight as a tangent to the freely stretched area of the membrane 6, i.e. practically only over the surrounding supporting shoulder 12. As shown, the tearing behavior can be controlled least well with this course, because the crack formation starting from the tangential point moves inward in an uncontrolled manner spreads.

The in the Figures 8 to 10 The lines of weakness shown are not straight lines in the geometric sense. However, the general direction or an imaginary center line is straight. According to figure 8 the weakening line 7 is a wavy line which intersects the freely stretched annular surface of the membrane 6 between the supporting shoulder 12 and the central supporting structure 13 . The wavy line is arranged and configured in such a way that it does not touch or overlap the central support structure 13 . According to figure 9 the weakening line 7 is a zigzag line which also runs straight overall. A sufficient distance from the central support structure 13 is also maintained here.

According to figure 10 the line of weakness 7 has a plurality of side lines of weakness 26 which run transversely and which cross the line of weakness or abut from one side. Also, the side lines of weakness do not touch or overlap the central support structure 13 .

According to figure 11 the line of weakness 7 runs around the central support structure 13 in the shape of a square. The sides of the square are fairly close to the outer perimeter of the support structure. Of course, the line of weakness could also run around the support structure in a star shape, polygonal shape, circular shape or in any desired configuration. It would also be conceivable for one or more weakening lines, which extend up to the supporting shoulder 12, to be attached to a weakening line surrounding the support structure.

In all of the described embodiments, the central support structure could also be omitted in certain cases. In addition, it would be conceivable that the general direction of the at least one weakening line is not straight but curved. With regard to production from an endless strip of film, however, a generally straight alignment is expedient.

Overall, these exemplary embodiments show how crack formation can be optimally controlled and changed with the aid of the weakening line. Of course, any other variants of weakening patterns would be conceivable. Instead of burning out using The weakened zone could also be produced by laser using other suitable methods, for example by burning out with the aid of a heated tool or by mechanically scribing or removing.

Claims (17)

1. A capsule (1) for the preparation of a beverage comprising a chamber (3) containing at least one substance, said chamber having an outlet portion (4) formed by a membrane (6) rupturing under internal pressure in the chamber to form an outlet opening (5), and wherein the membrane is provided with at least one weakening line (7) for defining the outlet opening, wherein the membrane (6) is a composite foil (8) comprising at least one metal foil (9) and at least one plastic foil (10) and wherein the weakening line (7) is arranged only in the plastic foil (10), wherein the outlet portion (4) is circular, characterized in that the weakening line (7) forms an uninterrupted line traversing the outlet portion (4), or the weakening line (7) surrounds a supporting structure (13) arranged on the side facing away from the chamber (3) in a freely stretched region between the supporting structure (13) and an outer periphery of the outlet portion (4).
2. Capsule according to claim 1, wherein the membrane (6) consists of an aluminium foil with a laminated PET layer.
3. Capsule according to claim 1 or 2, wherein a sealing lacquer (11) for sealing the membrane onto a supporting structure, in particular onto a supporting shoulder (12) of the capsule body (2), is applied to the side of the aluminium foil facing away from the plastic foil.
4. A capsule according to claim 2 or 3, wherein the aluminium foil has a wall thickness of 6 to 30µm, preferably of 15µm.
5. Capsule according to any one of claims 1 to 4, wherein the plastic film (10) faces the closed chamber (3).
6. A capsule according to any one of claims 1 to 5, wherein the line of weakness (7) forms a straight line traversing the outlet portion.
7. A capsule according to any one of claims 1 to 5, wherein the outlet portion (4) is supported on the side facing away from the closed chamber by a preferably circular support structure (13), the line of weakness forming a chord intersecting the outlet portion between the outer periphery and the support structure.
8. A capsule according to any one of claims 1 to 5, wherein the line of weakness (7) surrounds the support structure (13) in the form of a polygon, a circle or any curve.
9. A capsule according to any one of claims 1 to 8, wherein the chamber (3) is arranged in, or formed by, a capsule body (2) which is closed with a lid (19).
10. A capsule according to any one of claims 1 to 9, wherein the membrane (6) is mounted on a preferably circular support shoulder (12) formed by the capsule body (2).
11. Capsule according to any one of claims 1 to 10, wherein a filter (14), in particular a filter fleece, a perforated foil or a perforated filter plate, is arranged between the chamber (3) and the membrane (6).
12. Capsule according to any one of claims 1 to 11, wherein an outlet nozzle (16) is arranged on the side of the membrane (6) facing away from the chamber (3).
13. The capsule of any one of claims 1 to 12, wherein the line of weakness is formed as a zigzag line or a meander line or a wavy line.
14. The capsule of any one of claims 1 to 13, wherein a plurality of weakening side lines extend from the line of weakness transversely thereto.
15. A capsule according to any one of claims 1 to 14, wherein the membrane ruptures under an internal pressure in the chamber between 0.5 and 20 bar in the region of the line of weakness such that the membrane deforms plastically without recovery property and that an opening with an internal width of more than 1 mm is formed.
16. A method of manufacturing a capsule (1) according to any one of claims 1 to 15, characterised in that the line of weakness (7) in the plastic film (10) is produced by ablation by means of a laser.
17. The method according to claim 16, wherein the composite film (8) is formed as a windable tape (25) and wherein first a line of weakening (7) is produced, preferably extending in the direction of the tape, and subsequently the membrane is punched out of the tape and inserted into the capsule.

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