EP3251976A2 - Capsule for preparing a beverage - Google Patents

Abstract

A capsule (1) for the production of a beverage comprises a capsule body (2) with a closed chamber (3) containing a substance. The closed chamber has an outlet section (4) which is formed to form an outlet opening (5) by a membrane (6) tearing open under internal pressure in the closed chamber. To define the outlet opening, the membrane is provided with at least one line of weakness (7). The membrane consists of a composite film (8) comprising a metal foil (9) and a plastic film (10). The weakening line (7) is arranged only in the plastic film (10). By this measure, the tearing behavior of the membrane (6) can also be controlled on very thin metal foils. In addition, the weakening line can be easily produced.

Description

The invention relates to a capsule for the preparation of a beverage according to the preamble of claim 1. Such capsules are widely used in particular for the preparation of coffee. They are also used for tea or for mixed drinks. Accordingly, the substance contained in the closed chamber is either extracted by the passage of hot water through the capsule, e.g. with coffee powder, or it is dissolved by the hot water, such as with milk powder.

In many capsule systems, the input-side opening of the capsules already takes place when inserted into a beverage preparation machine. Mandrels or knives penetrate a capsule wall or the capsule lid for the introduction of hot water. On the output side, the capsule is opened by building up the internal pressure and tearing a membrane along at least one line of weakness.

Already by the DE 27 52 733 A1 has become known a cartridge for the production of a beverage, which consists of a dense body made of aluminum sheet, which is closed by a membrane. The membrane has a line of weakness defining 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 horseshoe.

By the EP 2 891 615 A1 Also, a capsule for the preparation of a beverage has become known, in which the lid of the capsule forms not the outlet side, but the inlet side. At the bottom of the capsule an outlet nozzle is arranged, whose bottom inlet is closed with a bursting membrane. The bursting membrane has star-shaped outgoing lines of weakness from the center in order to form a uniform opening as the internal pressure increases.

By the EP 2 616 367 B1 a cartridge for coffee and soluble products for the production of a beverage has become known. The cartridge has a tubular container body whose ends are closed with a membrane. Each membrane consists of a composite foil of, for example, aluminum and plastic foil. In the plastic film, a plurality of small incisions is provided which form under pressure small openings in the membranes.

A disadvantage of the known capsules is that the application of lines of weakness in relatively thin aluminum foils is difficult or almost impossible. However, if the wall thicknesses are dimensioned too large, a high internal pressure must be built up for bursting. It is therefore an object of the invention to avoid the disadvantages of the known and to provide a capsule whose bursting membrane can be produced inexpensively, whereby the bursting behavior can be controlled within a large pressure range. This object is achieved according to the invention 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. In this case, the preferably closed chamber has an outlet section, which is formed to form an outlet opening by a membrane which tears open under internal pressure in the chamber. The membrane can directly form the lid or the bottom of the capsule or it can be arranged inside the capsule. The chamber is in a capsule body is arranged or is formed by this. This capsule body may be closed with a lid, which also consists of a film of metal or plastic. The chamber is substantially liquid-tight and airtight 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 formed aroma-tight relative to the outside atmosphere, so that oxidation is prevented by penetrating oxygen. 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 weakening line whose shape may vary. Of course, the membrane may also be provided with a plurality of, for example, 2, 3, 4, 5 or more weakening lines, which may also be interconnected. According to the invention, the membrane consists of a composite foil comprising at least one metal foil and at least one plastic foil, the weakening zone being arranged only in the plastic foil. The weakening zone may have any geometric layouts and, for example, consist of a combination of surfaces and lines.

The metal foil, for example made of aluminum remains completely intact and the tear behavior is determined exclusively by the arranged in the plastic film weakening zone. It has surprisingly been found that the weakening zone in the plastic film is completely sufficient, and that in the case of a weakening line, the crack in the metal foil exactly follows the line of weakness in the plastic film. Thus, relatively thin metal foils can be used, which also in a tear down deeper internal pressure reliably. A weakening line in the plastic film can be attached much easier than in the metal foil.

Particularly advantageous is a membrane has been found, which consists of an aluminum foil with a laminated PET (polyethylene terephthalate) layer. Such films are already used in the packaging industry and are available as standard. The production costs can be significantly reduced. Other food grade plastics are conceivable.

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

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

Optimum results are achieved when the plastic film faces the weakening zone of the chamber. Depending on the course of the weakening zone, the resulting internal stress under tension causes, wholly or partially, a tear in the film following the weakening zone.

If the weakening zone is at least one line of weakness, this may be rectilinear or curved or even angled. For example, a wavy line or a meandering line would be conceivable. The line of weakness can run continuously or it would also be an interrupted course conceivable. The uninterrupted course of the line of weakness on the outlet section has the advantage that the outlet opening can be better controlled, and in such a way that the burst membrane does not hinder the outflow of the beverage.

The outlet portion may be circular and the line of weakness may form a straight line traversing the outlet portion. This creates an elongated crack in the membrane. The membrane is similar to a tympanum freely stretched and bulges when building up the internal pressure of the closed chamber looking convex outward.

However, the outlet section can also be of circular design and be supported on the side facing away from the chamber by a preferably circular support structure, the weakening line forming a chord which intersects the outlet section between the outer periphery and the support structure. Evidently, the membrane is designed as an annular surface which is supported not only on the outer circumference, but also in the center. The line of weakness intersects this annular surface as a chord. Of course, it would also be conceivable that the weakening line cuts the circular ring surface from the center radially outwards.

Finally, the outlet section can also be of circular design, the weakening line forming a tangent to the free-tensioned region of the membrane. This is conceivable with or without central support. In such a case, the line of weakness does not cause weakening in the free-tensioned Area of the membrane, but in the immediately adjacent region of the attachment on 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 line of weakness can surround the support structure. In this case, the weakening line runs in the released region between the support structure and the outer circumference of the outlet section, wherein the configuration of the weakening line can be polygonal, circular or any curve.

The membrane may be mounted on a preferably circular support shoulder, which is formed by the capsule body and which is thus formed integrally therewith. Of course, other arrangements of the membrane within the capsule would be conceivable. For example, the membrane could be fastened directly on 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 need not necessarily be part of the capsule body, but could also be arranged on a separate component. However, if the membrane is supported and attached not only to its circular periphery but also in the center, the control of the tear behavior at the line of weakness is particularly delicate. In fact, the edges of the support points also influence the tear behavior at the annular membrane spanning the rupture membrane because, due to the physical conditions without a weakening line, the rice tension would be greatest there. A "punching" of the central support structure by However, the membrane is not desirable because it could hinder the drainage of the beverage. By the proposed arrangement of the weakening line this can be reliably prevented.

The at least one weakening line, which forms a straight line, a tendon or a tangent in the sense of the present application, does not necessarily have to be understood as the shortest connection of two points on the membrane. Rather, it is meant in a generalized sense, the general orientation or arrangement of the line of weakness.

When the beverage produced with the capsule is an extract, such as e.g. Coffee or tea, the solid ingredients in the chamber must be retained. In this case, a filter, in particular a filter fleece, a perforated foil or a perforated filter plate can be arranged between the chamber and the membrane. Such filter media are already known in the prior art and will not be described in detail here.

Depending on the capsule system and on the type of preparation machine, an outlet nozzle can be arranged on the side of the membrane facing away from the chamber. This makes it possible that the beverage from the capsule can be passed directly into a drinking vessel.

Depending on the desired opening behavior, the weakening line may be formed as a zigzag line or as a meander line or as a wavy line. It is also conceivable that from the at least one line of weakness emanating several transverse to it weakening side lines. These can either cross the line of weakness or just hit it from one side. The proposed variants can when tearing Openings are created, which reliably prevents their edges close again.

In order to create a sufficiently large flow opening, it is particularly advantageous if 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 plastically deformed without return property and that an opening with a clear width of more than 1 mm is formed. The term clear width is to be understood as the distance between the adjacent edges of an opening. Particularly advantageously, an opening is formed which is greater than 1 mm ^{2 in} total.

The invention also relates to a method for producing a membrane for a capsule according to the invention or for producing such a capsule. The weakening zone is produced in the plastic film by ablation by means of laser, in particular by laser cutting. With the help of a laser, the width and depth of the attenuation zone can be precisely determined without weakening the metal layer.

A particularly optimal process results when the composite film is formed as a wound-up tape and when first a weakening line is preferably generated extending in the tape direction. Of course, several weakening lines can be generated side by side in the direction of tape. The thus processed band forms a semi-finished product, from which then the membrane for the capsule are punched out of the band and inserted into the capsules. The punching is done so relative to the linear line of weakness that it passes through the membrane at the desired location.

The covering of the unfilled capsules with the prepared band and the subsequent punching and insertion of the membrane can be carried out immediately after one another in a continuous working process. Alternatively, it is also conceivable that the attachment of the line of weakness, it is done by laser or other aids directly to the workstation before punching and sealing.

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

Further individual features and advantages of the invention will become apparent 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:

FIG. 1:

A perspective sectional view through an inventive capsule with a membrane at the bottom of the capsule;

FIG. 2:

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

FIG. 3:

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

Figures 4-7:

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

Figures 8-11:

Schematic representations of alternative embodiments of a line of weakness.

FIG. 1 shows a capsule 1, as shown for example in the WO 2015/124558 A1 is described in more detail. The rotationally symmetrical capsule body 2 has a capsule bottom 17 and a capsule side wall 18. The capsule body 2 is closed by a cover 19 on a circumferential collar. Integral with the capsule bottom 17, a circumferential support shoulder 12 is formed, on which an only partially visible membrane 6 is sealed. Also integrally formed with the capsule bottom 17 is an outlet 16, in the center of which an elongate flow element 23 is held. The facing against the inside of the capsule region of the outlet nozzle forms a support structure 13 (FIG. FIG. 2 ) which is firmly connected to the membrane 6 and supports it.

In the capsule body a cup insert 20 is arranged and locked on the ground with a latching connection 24. Towards the side of the lid 19, the cup insert 20 is supported with a circumferential collar 21 on the capsule side wall 18. In cup use, for example, coffee powder is included.

The bottom of the cup insert 20 is formed as a hole filter 14, which retains the coffee grounds during the extraction process. For stiffening the filter bottom stiffening ribs 22 are arranged, of which in FIG. 1 one is cut in the whole length. The cup insert 20 could also be replaced by another insert or it could be omitted altogether if the substance is a soluble product such as milk powder.

The inside of the capsule body evidently forms a closed chamber 3, whose outlet section is formed by the already mentioned membrane 6.

Further details of this arrangement will be apparent FIG. 2 , The cup insert 20 is removed here and also the sealed onto the circumferential support shoulder 12 membrane 6 is only partially shown, so that the underlying support structure 13 is still partially visible. This inner part of the outlet nozzle 16 has a plurality of outlet slots 15 extending in the longitudinal direction of the outlet nozzle. The central portion of the support structure 13 is also provided with such slots 15.

The membrane 6 is provided with a linear line of weakness 7 which traverses the eccentric outlet section 4 formed by the membrane eccentrically. 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 building up internal pressure, the membrane 6 tears along the weakening line 7, whereby an outlet opening 5 is formed. Through this, the liquid flows into the area under the membrane 6 and through the slots 15 in the outlet 16.

FIG. 3 schematically shows the structure of a composite film 8, from which the membrane 6 is made. On a metal foil 9, preferably made of aluminum, a plastic film 10 is preferably laminated from PET. On the opposite side can a sealing wax 11 may be applied so that the composite film can be fixed in a simple manner. As shown, the weakening zone formed as a weakening line 7 is arranged only 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 of aluminum, for example, here have a wall thickness of 15μ. The weakening zone could also be formed substantially wider in relation to the total wall thickness of the membrane, as shown here.

The FIGS. 4 to 7 show schematically each on the left side each formed as a wound tape composite film 8, for example, as described above. Depending on the size of the membrane to be produced, the foil strip has a width b. At a distance x from an outer edge of the belt an endless line of weakness 7 is arranged, which extends linearly in the longitudinal direction of the film strip. The band schematically shows the subsequently auszustanzende membrane 6 and also the basis of FIG. 2 described circumferential support shoulder 12 and the central support structure 13th

According to FIG. 4 extends the line of weakness 7 as a chord between the circumferential support shoulder 12 and the central support structure 13. As shown on the right side, it forms when bursting the membrane 6, an opening 5 in the form of a longitudinal slot which is bounded on both sides by the circumferential support shoulder. This is a preferred embodiment, because the opening behavior can be controlled well.

In the embodiment according to FIG. 5 The weakening line runs through the center of the circumferential support shoulder 12 and the central support structure 13. In this case, openings 5a, 5b form in the freely stretched region of the membrane 6. However, the membrane remains firmly connected to the support structure 13.

In the embodiment according to FIG. 6 forms the weakening line 7 similar to the embodiment according to FIG. 4 also a tendon, which cuts the membrane in the freely stretched area. However, the chord is located far outside in the area of the outer diameter, which is evident, the points at which the line of weakness 7 intersects with the support shoulder 12 are close to each other. Evidently, this changes the tear behavior of the membrane and the rice tension causes a crack which expands against the central support structure 13.

In the embodiment according to FIG. 7 the weakening line 7 only just straight as a tangent to the free-stretched region of the membrane 6, so practically only on the circumferential support shoulder 12. As shown, can be controlled with this course the tear behavior least good, because the cracking from the point of tangency uncontrolled against inside spreads.

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

According to FIG. 10 the weakening line 7 has several weakening side lines 26, which run transversely and which cross the weakening line or abut it from one side. The weakening side lines also do not touch or overlap the central support structure 13.

According to FIG. 11 the weakening line 7 extends around the central support structure 13 in the form of a square. The sides of the square are quite close to the outer periphery of the support structure. Of course, the line of weakness could also be star-shaped, polygonal, circular, or in any configuration around the support structure. It would also be conceivable for one or more weakening lines, which extend as far as the support shoulder 12, to adjoin a weakening line surrounding the support structure.

In all 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 the production of an endless foil strip, however, a general straight alignment is expedient.

Overall, these embodiments show how the 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 by means of Laser, the zone of weakening could also be produced by other suitable methods, for example by burning with the aid of a heated tool or by mechanical scratching or ablation.

Claims (18)

Capsule (1) for the preparation of a beverage, comprising a chamber (3) containing at least one substance, the chamber having an outlet section (4) which is formed by a membrane (6) bursting under internal pressure in the chamber to form an outlet opening (5) The diaphragm (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 film (10), characterized in that the weakening line (7) is rectilinear or curved or angled and is executed uninterrupted. Capsule according to claim 1, wherein the membrane (6) consists of an aluminum foil with a laminated PET layer. Capsule according to claim 1 or 2, wherein on the side facing away from the plastic film side of the aluminum foil, a sealing wax (11) for sealing the membrane on a support structure, in particular on a support shoulder (12) of the capsule body (2) is applied. Capsule according to claim 2 or 3, wherein the aluminum foil has a wall thickness of 6 to 30μ, preferably of 15μ. Capsule according to one of claims 1 to 4, wherein the plastic film (10) faces the closed chamber (3). Capsule according to one of claims 1 to 5, wherein the outlet portion (4) is circular and wherein the line of weakness (7) forms a straight line which traverses the outlet portion. Capsule according to one of claims 1 to 5, wherein the outlet portion (4) is circular and is supported on the side facing away from the closed chamber by a preferably circular support structure (13), wherein the line of weakness forms a chord which the outlet portion between the Outer circumference and the support structure cuts. Capsule according to one of claims 1 to 5, wherein the outlet portion (4) is circular and wherein the line of weakness (7) forms a tangent to the free region of the membrane. Capsule according to one of claims 1 to 5, wherein the outlet portion (4) is circular and is supported on the side facing away from the closed chamber by a preferably circular support structure (13), wherein the line of weakness surrounds the support structure. Capsule according to one of claims 1 to 9, wherein the chamber (3) in a capsule body (2) is arranged, or is formed by this, which is closed with a lid (19). A capsule according to any one of claims 1 to 10, wherein the membrane (6) is mounted on a preferably circular support shoulder (12) formed by the capsule body (2) becomes. Capsule according to one of claims 1 to 11, wherein between the chamber (3) and the membrane (6) a filter (14), in particular a filter fleece, a perforated foil or a perforated filter plate is arranged. Capsule according to one of claims 1 to 12, wherein an outlet nozzle (16) is arranged on the side of the membrane (6) facing away from the chamber (3). Capsule according to one of claims 1 to 13, wherein the weakening line is formed as a zigzag line or as a meander line or as a wavy line. A capsule according to any one of claims 1 to 14, wherein the line of weakness emanates a plurality of transverse weakening lines extending transversely thereto. Capsule according to one of claims 1 to 15, 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 plastically deformed without return property and that an opening with a clear width of more is formed as 1 mm. A method of manufacturing a capsule (1) according to any one of claims 1 to 16, characterized in that the line of weakness (7) in the plastic film (10) is produced by ablation by means of laser. A method according to claim 17, wherein the composite film (8) is formed as a rollable tape (25) and wherein first a weakening line (7) is preferably produced extending in the band direction and then the membrane is punched out of the band and inserted into the capsule.

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