EP2892824B1

EP2892824B1 - A beverage capsule with anti-dripping membrane

Info

Publication number: EP2892824B1
Application number: EP13756172.6A
Authority: EP
Inventors: Christian Talon
Original assignee: Nestec SA
Current assignee: Nestec SA
Priority date: 2012-09-05
Filing date: 2013-09-03
Publication date: 2017-05-10
Anticipated expiration: 2033-09-03
Also published as: US20150232263A1; ES2629178T3; WO2014037339A1; CN104603027A; CN104603027B; AR092453A1; EP2892824A1; JP2015530142A

Description

Field of the invention

The present invention concerns an ingredient capsule for use in a food preparation machine, for instance in a liquid food preparation machine.

Background of the invention

Beverage preparation machines are well known in the food science and consumer goods area. Such machines allow a consumer to prepare at home a given type of beverage, for instance a coffee-based beverage, e.g. an espresso or a brew-like coffee cup.
Today, most beverage preparation machines for in-home beverage preparation comprise a system made of a machine which can accommodate portioned ingredients for the preparation of the beverage. Such portions can be soft pods or pads, or sachets, but more and more systems use semi-rigid or rigid portions such as rigid pods or capsules. In the following, it will be considered that the beverage machine of the invention is a beverage preparation machine working with a rigid or semi-rigid capsule.
The machine comprises a receptacle or cavity for accommodating said capsule and a fluid injection system for injecting a fluid, preferably water, under pressure into the capsule. Water injected under pressure in the capsule, for the preparation of a coffee beverage according to the present invention, is preferably hot, that is to say at a temperature above 70°C. However, in some particular instances, it might also be at ambient temperature, or even chilled. The pressure inside the capsule chamber during extraction and/or dissolution of the capsule contents is typically about 1 to about 8 bar for dissolution products and about 2 to about 12 bar for extraction of roast and ground coffee. Such a preparation process differs a lot from the so-called "brewing" process of beverage preparation - particularly for tea and coffee, in that brewing involves a long time of infusion of the ingredient by a fluid (e.g. hot water), whereas the beverage preparation process allows a consumer to prepare a beverage, for instance coffee, within a few seconds.
The principle of extracting and/or dissolving the contents of a closed capsule under pressure is known, and consists typically of inserting the capsule in a receptacle or cavity of a machine, injecting a quantity of pressurized water into the capsule, generally after piercing a face of the capsule with a piercing injection element such as a fluid injection needle mounted on the machine, so as to create a pressurized environment inside the capsule either to extract the substance or dissolve it, and then release the extracted substance or the dissolved substance through the capsule. Capsules allowing the application of this principle have already been described for example in applicant's European patents n° EP 1472156 B1 , and EP 1784344 B1 .
Machines allowing the application of this principle have already been described for example in patents CH 605 293 and EP 242 556 . According to these documents, the machine comprises a receptacle or cavity for the capsule and a perforation and injection element made in the form of a hollow needle comprising in its distal region one or more liquid injection orifices. The needle has a dual function in that it opens the top portion of the capsule on the one hand, and that it forms the water inlet channel into the capsule on the other hand.
The machine further comprises a fluid tank - in most cases this fluid is water - for storing the fluid that is used to dissolve and/or infuse and/or extract under pressure the ingredient(s) contained in the capsule. The machine comprises a heating element such as a boiler or a heat exchanger, which is able to warm up the water used therein to working temperatures (classically temperatures up to 80-90°C). Finally, the machine comprises a pump element for circulating the water from the tank to the capsule, optionally though the heating element. The way the water circulates within the machine is e.g. selected via a selecting valve means, such as for instance a peristaltic valve of the type described in applicant's European patent application EP 2162653 A1 .
When the beverage to be prepared is coffee, one interesting way to prepare the coffee is to provide the consumer with a capsule containing roast and ground coffee powder, which is to be extracted with hot water injected therein.
In many instances, the machine comprises a capsule holder for holding a capsule, which is intended to be inserted in and removed from a corresponding cavity or receptacle of the machine. When a capsule holder is loaded with a capsule and inserted within the machine in a functional manner, the water injection means of the machine can fluidly connect to the capsule to inject water therein for a food preparation, as described above. A capsule holder was described for example in applicant's European patent EP 1967100 B1 .
Capsules have been developed for such an application of food preparation, and in particular for beverage preparation, which are described and claimed in applicant's European patent EP 1784344 B1 , or in European patent application EP 2062831 .
In short, such capsules comprise typically:

a hollow body and an injection wall which is impermeable to liquids and to air and which is attached to the body and adapted to be punctured by e.g. an injection needle of the machine,
a chamber containing a bed of roast and ground coffee to be extracted, or a soluble ingredient or mix of soluble ingredients,
an aluminium membrane disposed at the bottom end of the capsule, closing the capsule, for retaining the internal pressure in the chamber.

The aluminium membrane is designed for being pierced with piercing means that are either integral with the capsule, or located outside of said capsule, for example within a capsule holder of the machine.
The piercing means are adapted for piercing dispensing holes in the aluminium membrane when the internal pressure inside the chamber reaches a certain pre-determined value.
Also, optionally, the capsule can further comprise means configured to break the jet of fluid so as to reduce the speed of the jet of fluid injected into the capsule and distribute the fluid across the bed of substance at a reduced speed.
Capsules of the prior art feature an injection wall or membrane (referred to as top membrane) which is to be pierced by a fluid injection element (e.g. needle) of a beverage preparation machine being part of a fluid system. When fluid is injected in the capsule compartment, a pressure is built up, which serves as an extraction means for extracting and/or dissolving ingredients contained inside the capsule, as described above. Such ingredients can be for instance a bed of roast and ground coffee. Alternatively or in combination with roast and ground coffee, the ingredients can comprise soluble ingredients, such as for instance beverage premixes.
At the end of the beverage production process the capsule is opened both at an inlet side and at an outlet side. Although the biggest portion of the liquid introduced into the interior of the capsule will be drained from the water, there will always some residual liquid remaining in the capsule after the beverage production process.
Particularly when the capsule is then taken out from the beverage production machine, there is the problem of water or beverage dripping e.g. from the water inlet side of the capsule. Such dripping forces to consumer to leave ones cup below the capsule dispensing outlet several seconds after the completion of the dispensing, which is undesirable. In some instances, dripping can also cause messiness in or around the machine, in case the consumer has removed the cup from below the dispensing outlet, which is also undesirable. It is thought that this dripping is particularly promoted by air entering the capsule from the beverage outlet side.
The invention therefore has the object to reduce the risk of residual liquid dripping out of the capsule after the completion of the beverage production process.

Summary of the invention

The objective set out above is met with a beverage capsule comprising capsule side walls, a capsule top, and a capsule bottom having a dispensing outlet, that define a chamber for containing a food or beverage precursor ingredient soluble and/or extractable when a fluid is injected inside said chamber under pressure, said capsule further comprising a pressure-sensitive membrane located between said ingredient and said dispensing outlet, characterized in that said pressure-sensitive membrane comprises at least one weakened or precut zone defining a non-reclosable opening which:

(i) elastically and plastically opens, respectively widens when the fluid pressure inside said capsule reaches a predetermined value between 0.5 and 20 bar relative pressure, preferably between 1.0 and 15 bar, and then
(ii) maintains a widen configuration after the fluid pressure within the chamber is released to an atmospheric pressure value, such that the width of said at least one opening does not exceed 1 mm, preferably that does not exceed 0.5mm.

In a highly preferred embodiment of the invention, said at least one precut opening is a slit having a length to width ratio comprised between 1:1 and 1000:1, preferably comprised between 1:1 and 50:1, more preferably comprised between 5:1 and 20:1.
Alternatively, the precut opening can take the form of a cross, an arcuate segment, a zigzag, or any other shape suitable to provide the mechanical properties mentioned above, i.e. being able to sufficiently open under pressure during dispensing of the beverage, and then partially reclose, or otherwise maintain a widen configuration when in-capsule pressure drops down to a value substantially equivalent to the atmospheric pressure. Such alternative shapes can be beneficial in allowing products to flow and be dispensed to a consumer cup, which have various viscosities, and optionally contain small edible particles, like for instance croutons, small herb or fruit pieces, etc., while providing good anti-dripping properties to the capsule after dispensing of the beverage.
In a highly preferred embodiment of the invention, and in order to achieve the opening, widening and reclosability properties mentioned above, the material used for the pressure-sensitive membrane is has the following physical characteristics: a Young's modulus comprised within the range of 800 MPa to 5000 MPa, a Yield point comprised within the range of 10 MPa to 50 MPa, and a melting point comprised within the range of 100°C to 200°C, preferably within the range of 140°C to 180°C, a thickness that is comprised between 50 µm and 800 µm, preferably between 100 µm and 600 µm.
Advantageously, the pressure-sensitive membrane is made out of at least one layer of a thermoplastic material, selected within the list of: polyethylene (PE), polypropylene (PP), ethylene vinyl alcohol (EVOH), polystyrene (PS), or a combination thereof.
Also preferably, the capsule side walls and capsule top are moisture and oxygen impermeable, and wherein said capsule further comprises a pierceable or tearable moisture and oxygen barrier bottom membrane, such that the capsule chamber is closed.
The bottom membrane is preferably openable by piercing by action of an piercing element located within or outside of the capsule vicinity.
In a preferred embodiment, the beverage prepared within said capsule has a viscosity comprised between 0.1 and 100 mPa.s.
The capsule of the invention preferably comprises a precursor ingredient for making a beverage comprised within the list of: soups, fruit juices, vegetable juices, bouillons, coffee, chocolate, tea, milk or creamer, or a combination thereof.

Brief description of the drawings

Additional features and advantages of the present invention are described in, and will be apparent from, the description of the presently preferred embodiments which are set out below with reference to the drawings in which:

Figure 1 is a perspective side view of a beverage preparation machine suitable for use with a capsule according to the invention;
Figure 2 is a schematic enlarged view of the interior of a brewing head of the machine illustrated in figure 1;
Figure 3 is a schematic perspective cut view showing the interior of a capsule according to the invention;
Figure 4 is a schematic split view similar to figure 3;
Figure 5 is a top view of a dispensing membrane with slits according to the invention;
Figure 6 is an enlarged perspective view of the bottom portion of a capsule according to the invention, wherein the slits of the bottom dispensing membrane are closed;
Figure 7 is a similar view to figure 6, wherein the slits of the bottom dispensing membrane are open;
Figure 8 is an enlarged top perspective view of the bottom part of a capsule according to the invention, wherein a slit is shown in its open configuration;
Figure 9 is a schematic partially cut view of an alternative embodiment of the capsule according to the invention.

Detailed description of the invention

The capsule according to the present invention is meant to be used with a beverage preparation machine illustrated in figure 1 , thus forming a beverage preparation system.
As shown in figure 1 , the machine 1 comprises a machine body 2, a water reservoir 3 that can be removed from the machine body 2 for refill. The body 2 comprises a on/off push button 4. The machine 1 further comprises a extraction head 5. The head 5 comprises a water temperature selector for hot or cold water taking the form of two buttons 6 (one for selecting a hot beverage, the other for cold), a locking lever 7, and an opening for insertion of a capsule holder 8. The machine 1 further comprises a cup tray 9, for holding a cup under the extraction head. The machine further comprises a control panel 10 comprising a selector wheel for selecting for instance the volume of beverage to be dispensed, as well as a screen, wherein data about the beverage preparation settings are represented.
The capsule holder 8 is adapted to receive a capsule 11. A view of the capsule holder 8 is shown in figure 2 , wherein a capsule 11 is disposed, said holder 8 and capsule 11 being inserted into the corresponding receptacle of the extraction head as illustrated in figure 1 . The capsule holder 8 comprises a body portion 12 designed as a receptacle for the capsule 11, and further comprises a handle 13.
Figure 2 shows the interior of the extraction head 5 of the machine, with a receptacle 14 having guiding ramps 15 for guiding the capsule holder 8 therein. Once the capsule holder and capsule 11 are inserted into the receptacle 14, the extraction head of the machine is closed manually by the user actuating the locking lever 7 downwardly, which moves a needle plate 16 down, towards the upper surface of the capsule 11 and capsule holder 8. Doing this, a water injection needle 17 pierced through the top membrane 18 of the capsule. At this time, the capsule is functionally enclosed within the extraction head, and its peripheral upper edge 19 is tightly held between the upper surface of the capsule holder and the lower surface of the needle plate. The injection of water from the reservoir, through the pump, optionally through the heating element, and via the needle of the machine, into the capsule, can start.
As shown in figure 3 , the capsule 11 comprises capsule side walls 20 which define a generally frusto-conical body closed at its bottom by a bottom wall 21 integrally formed with the body side walls 20. The centre of the bottom wall 21 comprises a dispensing opening (or outlet) 22 to let the beverage prepared inside the capsule, flow out of said capsule into a cup placed here below. The capsule further comprises a pierceable aluminum membrane 23 that is sealed inside the capsule, close to the bottom wall 21, as well as a piercing plate 24 for piercing said aluminum membrane when pressure inside the capsule increases. The aluminum membrane 23 has a barrier function to protect the capsule contents against moisture and oxygen during storage.
The piercing plate is located between the aluminum membrane and the bottom wall of the capsule. Finally, the capsule is closed at its top by the pierceable membrane 18. All walls and membranes define a chamber, into which a beverage precursor ingredient is placed, which is meant to be mixed with the water injected through the water injection needle of the machine, as described above. The mix of the ingredient with the machine produces a beverage under pressure, that is dispensed when the capsule opens. The opening of the capsule occurs when the pressure inside the capsule is sufficiently high to either flex the aluminum membrane towards the piercing plate 24, or sufficiently high to simply tear the aluminum membrane open. During storage, the capsule is made out of such materials that it is moisture and oxygen barrier.
The invention will now be described in more detail with reference to figures 4 to 9 .
In a first embodiment of the invention illustrated in figures 4 to 8 , the capsule 11 further comprises a pressure-sensitive precut membrane 25 having four non-reclosable precut slits 26 which:

(i) elastically and plastically widen when the fluid pressure inside said capsule reaches a predetermined value between 1 and 20 bar relative pressure, as illustrated in figure 7 and then
(ii) maintain a widen configuration after the fluid pressure within the chamber is released to an atmospheric pressure value, such that the width of each of said slits 26 does not exceed 1 mm.

As shown in figure 4 which is an exploded schematic partially cut view of the capsule, the precut membrane 25 is sealed adjacent to, or at a close distance (i.e. less than 5mm, preferably less than 2mm, more preferably less than 1mm) from the aluminum membrane, and located between said aluminum membrane 23 and the ingredient contained within the capsule.
The precut membrane has the shape of a disc of thermoplastic film as illustrated in figure 5 , so as to follow the general frusto-conical shape of the capsule. It comprises four precut slits 26, spaced apart from each other and distributed across the surface of the membrane preferably - although not necessarily - at equal distances from each other. The slits have a length to width ratio comprised between 5:1 and 20:1. Their length is of about 3 to 5 mm, and they are located at a distance of about 10mm from the outer edge of the membrane.
The slits can be precut through the entire thickness of the membrane 25, or alternatively, they can be precut through only a portion of said membrane.
In that latter case, the slits are for instance precut by using a laser scoring technology, cutting through e.g. half of the thickness of the membrane 25, so as to establish a predetermined precut line of weakness along which the membrane will preferentially tear itself when a fluid pressure is built up inside the capsule. Such a configuration has the advantage that the precut membrane can be made out of a multilayer laminated thermoplastic material comprising at least one layer of a thermoplastic that is easily sealable onto the inner surface of the capsule side or bottom walls, and at least one material that is moisture and oxygen barrier, so as to guarantee a long shelf life for the capsule and its contents. In that case, of course, the laser scoring is performed such that the barrier layer of the membrane 25 is not cut, and the precut is performed only through layer(s) which do(es) not have a barrier function. This removes the need for an additional aluminium barrier membrane.
Importantly, the material that was chosen for manufacturing the membrane 25 is a polypropylene having a thickness comprised between 200 and 300µm, having a Young's modulus of about 1600 MPa and Yield limit of about 30 MPa. Its melting point is about 160°C. Such characteristics ensure that the precut slits open and widen under pressure and then reclose sufficiently to ensure that an anti-dripping effect is achieved according to the principles of the invention.
During storage of the capsule, and until said capsule is filled by injected water under pressure, the precut membrane 25 and the slits 26 are in the configuration shown in figure 6 . In such a configuration, the precut membrane 25 is located adjacent to the aluminium membrane 23, and the slits 26 are in a closed configuration.
After the capsule 11 has been inserted into the capsule holder and the latter is functionally inserted into the extraction head of the machine, as described above, the user can start a beverage preparation cycle as already described. As described above, the preparation of a beverage is performed by injecting under pressure a fluid (typically water) which is heated, or not, into the capsule through the injection needle that protrudes into the capsule chamber through the top membrane 18. As fluid is injected into the capsule chamber, a fluid pressure builds up inside the capsule and presses against the capsule walls and membranes, especially against the precut membrane 25. The force exerted by the fluid under pressure pushes onto the lips of the slits which are widen (or torn open in case the membrane 25 was not cut through its whole thickness as described above), as illustrated in figures 7 and 8 . At that stage, the aluminium membrane 23 (if one is present) is moved away from the precut membrane 25 as illustrated in figure 8 . Then the fluid presses onto the aluminium membrane if one is present, which is opened (by tearing, or by action of the piercing plate 24). The capsule is then opened and the beverage is dispensed by gravity in a cup (not shown in the drawing) placed below the capsule 11.
In a second embodiment of the invention illustrated in figure 9 , the pressure-sensitive precut membrane 25 is not sealed adjacent to the aluminium membrane 23 as it was the case for the first embodiment described above. The aluminium membrane 23 has a reduced surface and is sealed outside of said capsule 11, onto the external surface of the bottom wall 21 of the capsule, so as to tightly cover and sealingly close the dispensing opening 22 of the capsule. Further, the capsule does not comprise a piercing plate as it was the case for the first embodiment described above. In this case, the aluminium membrane is torn as the fluid pressure inside the capsule reaches a certain predetermined level. The working principle of the pressure-sensitive precut membrane 25 and the slits 26 is the same as described herein before with reference to the first embodiment of the invention.
The capsule according to the invention provides two beneficial effects during and after production of a beverage therein.
Firstly, the membrane with slits provides a filter effect that prevents big particles of non-dissolved ingredient to flow into the consumer cup (due to the width of the slits which do not open sufficiently to let these large particles out). The invention is particularly beneficial in that this filter effect is obtained simultaneously to a dispensing flow rate which is sufficient to guarantee that a large volume of beverage is dispensed within a few seconds. Typically, a 250ml long coffee cup can be dispensed within less than 10 seconds, and an espresso coffee cup of about 60ml can be dispensed within less than 5 seconds. This means that a minimal dispensing flowrate of 10ml/sec, preferably 20ml/sec, more preferably 25ml/sec can be achieved, while at the same time achieving a filter effect during the beverage dispensing phase which allows to retain particles larger than 2mm, preferably larger than 1mm, more preferably larger than 500µm.
Secondly, the membrane with slits provides an anti-dripping effect by capillarity: when the injection of water stops, the pressure inside the capsule is released, to a value which is substantially equal to the atmospheric pressure. At this time, the slits do not reclose completely due to their plastic deformation during the beverage dispensing step. However their width is reduced sufficiently to provide a capillarity effect, due to the elastic properties of their constitutive material, such that the remaining liquid inside the capsule does not drip by gravity, and is retained within the capsule.
The capsule top can be a plain membrane sealed to the top edges of the capsule, that is preferably moisture and oxygen barrier. Alternatively, said capsule top can be a perforated membrane or a filter membrane.
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

Claims

A beverage capsule (11) comprising capsule side walls (20), a capsule top, and a capsule bottom (21) having a dispensing outlet (22), that define a chamber for containing a food or beverage precursor ingredient soluble and/or extractable when a fluid is injected inside said chamber under pressure, said capsule (11) further comprising a pressure-sensitive membrane (25), characterized in that said pressure-sensitive membrane (25) comprises at least one weakened or precut zone defining a non-reclosable opening (26) which:
(i) elastically and plastically opens, respectively widens when the fluid pressure inside said capsule reaches a predetermined value between 0.5 and 20 bar relative pressure, preferably between 1.0 and 15 bar, and then

(ii) maintains a widen configuration after the fluid pressure within the chamber is released to an atmospheric pressure value, such that the width of said at least one opening (26) does not exceed 1 mm.
A capsule (11) according to claim 1, wherein said at least one precut opening is a slit (26) having a length to width ratio comprised between 1:1 and 1000:1, preferably comprised between 1:1 and 50:1, more preferably comprised between 5:1 and 20:1.
A capsule (11) according to any of the preceding claims 1 or 2, wherein the pressure-sensitive membrane is made out of a material having the following physical characteristics: a Young's modulus comprised within the range of 800 MPa to 5000 MPa, a Yield point comprised within the range of 10 MPa to 50 MPa, and a melting point comprised within the range of 100°C to 200°C, preferably within the range of 140°C to 180°C, a thickness that is comprised between 50 µm and 800 µm, preferably between 100 µm and 600 µm.
A capsule (11) according to any of the preceding claims, wherein said pressure-sensitive membrane (25) is made out of at least one layer of a thermoplastic material, selected within the list of: polyethylene (PE), polypropylene (PP), ethylene vinyl alcohol (EVOH), polystyrene (PS), or a combination thereof.
A capsule (11) according to any of the preceding claims, wherein the capsule side walls (20) and capsule top (18) are moisture and oxygen impermeable, and wherein said capsule further comprises a pierceable or tearable moisture and oxygen barrier bottom membrane (23, 25), such that the capsule chamber is closed.
A capsule (11) according to claim 5, wherein said bottom membrane is openable by piercing by action of an piercing element located within or outside of the capsule vicinity.
A capsule (11) according to any of the preceding claims, wherein the beverage prepared within said capsule has a viscosity comprised between 0.1 and 100 mPa.s.
A capsule (11) according to any of the preceding claims, which comprises a precursor ingredient for making a beverage comprised within the list of: soups, fruit juices, vegetable juices, bouillons, coffee, chocolate, tea, milk or creamer, or a combination thereof.