HK1161670A - Method for preparing a food liquid contained in a capsule by centrifugation and system adapted for such method - Google Patents

Description

Method for preparing a liquid food product contained in a capsule by centrifugation and system suitable for the method

Technical Field

The present invention relates to a device and a capsule system for preparing a food liquid from a food substance contained in a container by passing water through the substance using centrifugal forces.

Background

It is known to prepare beverages: wherein the mixture consisting of brewed coffee and coffee powder is separated by centrifugal force. This mixture is obtained by mixing hot water and coffee powder together for a set time. The water is then forced through a screen on which the powdered material is present.

The existing systems consist in placing coffee powder in a container, usually an irremovable part of the machine, as for example in EP 0367600B 1. Such devices have a number of disadvantages. First, the coffee powder must be properly portioned manually in the container. Secondly, the centrifuged coffee waste dries and it must be removed by scraping the container surface. Therefore, coffee preparation requires a large number of manual operations and is therefore time-consuming. Usually, the degree of freshness of the coffee also varies greatly and this affects the quality of the cup, since the coffee is generally from bulk packs or coffee ground from coffee beans in the container itself.

Moreover, depending on the manual dosing of the coffee and the brewing conditions (e.g. centrifugation speed, container size), the cup quality can vary greatly.

Thus, these systems have never achieved significant commercial success.

In german patent application DE 102005007852, the machine comprises a removable holder in which an open cup-shaped part of the receptacle is placed; other components or covers are attached to the drive axis of the machine. However, one disadvantage is the intensive manual operation. Another drawback is the difficulty in controlling the quality of the coffee due to the lack of control over the metering of the powder and the lack of control over the degree of freshness of the coffee powder.

Other devices for brewing coffee by centrifugal force are described in WO 2006/112691; FR 2624364; EP 0367600; GB 2253336; FR 2686007; EP 0749713; DE 4240429; EP 0651963; FR 2726988; DE 4439252; EP 0367600; FR 2132310; FR 2513106; FR 2487661; DE 3529053; FR 2535597; WO 2007/041954; DE 3529204; DE 3719962; FR 2685186; DE3241606 and US-A-4545296.

In particular, EP0651963 relates to a centrifugal separation unit comprising an elastic joint placed at the junction between the cartridge and the lid of the unit. The elastomeric joint provides both filtration and operating pressure control in the unit, thereby improving the crema. The unit is not an airtight container and for each new brewing cycle the used coffee has to be removed and the unit has to be refilled with new coffee. It is difficult to control the pressure by such elastic means and the pressure cannot be easily changed according to the type of beverage to be produced.

BE894031 relates to a centrifugal brewing system comprising a filter capsule which is not sealed but covered by filter paper.

Therefore, there is a need to propose a solution which provides a better control of the extraction parameters (such as pressure, flow rate, extraction time, etc.) and which therefore improves the quality of the food liquid delivered.

At the same time, there is a need for a way of preparing a food liquid which is more convenient and simpler than prior art centrifugal coffee preparation methods and at the same time provides a better quality of the cup-formed coffee by controlling important properties such as freshness and accurate metering of the substance.

In particular, there is a need for a system that enables providing a sufficient interaction time between hot water and the substance to be brewed and controlling the release of brewed liquid, thus improving important quality attributes such as coffee strength and crema or foam for coffee beverages.

Disclosure of Invention

The invention therefore relates to a liquid food preparation system for preparing a liquid food from a food substance by passing water through the substance in a capsule, comprising a preparation device and a capsule removably insertable in the device, said system comprising a water injection head in the capsule and a capsule holder for holding the capsule in the device,

characterized in that the system comprises:

a water injector as part of the water injection head, the water injector being arranged for introducing water into the capsule,

means for driving the capsule holder to perform a centrifugal separation action about an axis of rotation, an

Wherein the opening means is configured to form at least one liquid delivery outlet in the capsule at least partly in response to centrifugal forces of liquid exerted in the capsule.

Preferably, the device comprises at least one opening means for providing at least one liquid delivery outlet in a capsule which is arranged in an offset position with respect to the central axis of the capsule holder. The opening means is preferably located on the surface of the injection head.

Preferably, the opening means comprise a set of piercing elements distributed along a substantially circular path around a central axis. For example, the opening means may form a truncated pyramid, a needle and/or a knife edge.

More specifically, the water injection head comprises a water injector and a rotary engagement member for sealingly engaging the capsule on the capsule holder. Preferably, the rotary engagement member exerts a pressure on the periphery of the capsule, which is itself supported by the capsule holder. Thus, the engagement member and the capsule holder rotate together while holding the capsule firmly in place in the capsule holder during centrifugation. The water injector may be stationary or move with the rotary engagement member.

In one embodiment, the opening means of the liquid delivery outlet is a piercing member, which may be part of a rotational engagement member of the filling head.

Preferably, the piercing members may be distributed at regular/fixed intervals along a substantially circular path, so as to provide a uniform liquid transfer at the periphery of the capsule. For example, the number of piercing members may be from 10 to 200, most preferably between 50 and 100.

The piercing member may be engaged in the capsule and participate in transferring rotational momentum to the capsule during rotation.

According to an aspect of the invention, the opening member is configured to provide the liquid delivery outlet of the capsule when an internal pressure of the liquid against the peripheral wall of the capsule due to the liquid being centrifuged through the substance in the capsule exceeds a threshold pressure.

For this purpose, the opening means may be an element that leaves or contacts the capsule when the water injection head and the capsule holder are closed with respect to the capsule. Thus, as the pressure of the liquid on the peripheral wall of the capsule increases, an outlet is formed by the deformation of the wall of the capsule (e.g. the cover membrane) against the opening member. This configuration makes it possible to delay the release of the beverage from the capsule. When the operating pressure threshold has been reached at the capsule peripheral wall, the outlet is fully formed. Thus, the interaction between the ingredients in the capsule and the water can be prolonged. Depending on the resistance to puncture of the capsule delivery wall, the release of the beverage through the outlet can be successfully controlled.

With respect to the capsule, the capsule peripheral wall may be part of the perforable membrane. For example, the peripheral wall may be a peripheral portion of a membrane transverse to the axis of rotation of the capsule in the capsule holder. Preferably, the capsule has a side wall widening/expanding in the direction of the peripheral portion of the perforable membrane. Thus, the brewed liquid in the capsule is forced by centrifugal forces to move in the direction of the peripheral portion of the perforable membrane. In this case, the perforable membrane can be sealed on the flange/flange-like edge of the cup-shaped body of the capsule. In an alternative, the piercing wall may be a portion of the side wall of the cup-shaped body of the capsule.

The capsule may comprise a perforable membrane made of aluminium and/or a polymer material. In particular, the thickness of the pierceable film may be between 5 and 150 microns, preferably between 10 and 100 microns. The thickness of the membrane can be designed in such a way that: opening at a prescribed operating pressure and/or after a prescribed centrifugation time can be predicted. Thus, the thickness of the membrane may vary depending on the substance in the capsule and/or the beverage to be delivered.

In one embodiment, the pre-weakening of the peripheral wall of the capsule may be formed by an opening member in contact with the wall during closure of the device around the capsule, for example during engagement of the device on the capsule before a centrifugation operation. The pre-weakened portion of the wall may be a large number of through-holes having a cross-section smaller than the final pierced outlet or a weakened portion of material formed by reducing the wall thickness. The peripheral wall of the capsule may be sufficiently resilient to deform and elongate without immediately breaking against the piercing member. Thus, a certain delay of the release of beverage is provided before sufficient outlet channels for liquid to flow therethrough are formed.

The shape of the piercing member for the outlet is also important for properly controlling the piercing of the outlet in the capsule. A blunt piercing shape will provide a longer resistance of the capsule to piercing and a longer delay of liquid beverage release. Conversely, a sharper shape will provide faster delivery and shorter residence time of the liquid in the capsule.

The residence time of the liquid in the capsule also depends on the centrifugation speed, since the higher the speed, the higher the pressure and potentially the faster the centrifuged liquid passes through the ingredients in the capsule and is released from the capsule.

In a possible aspect of the invention, the syringe further comprises opening means, such as a piercing member. The opening means may be a piercing member arranged as a hollow piercing tube for injecting water into the capsule, preferably along the central axis of rotation of the capsule, such that the tube may be kept in a stationary state. It may be noted that the piercing member may also rotate with the engagement member of the injection head.

The piercing member of the syringe has a diameter of less than 5mm, preferably between 0.9 and 2.9 mm. In fact, the pressure in the capsule increases from the centre to the periphery. The water pressure in the central portion may approach zero but gradually increase outwardly. The small diameter of the injector thus provides a small inlet in the capsule, maintaining a relatively low liquid pressure at the inlet side of the capsule and thus reducing the total flow of liquid through the pierced inlet. Another advantage is also that the liquid sealing means may not necessarily surround the inlet side and the capsule can be properly vented when the liquid replaces the gas in the capsule.

The drive means of the capsule holder may be directly connected with the capsule holder or indirectly connected with the capsule holder. The direct connection with the capsule holder may be obtained by a rotary drive assembly comprising a rotary motor and transmission means connecting the motor with the bottom of the capsule holder. The transmission means may comprise suitable gear reduction or amplification means to provide the capsule holder with the correct transmission ratio depending on the speed of the motor. An indirect connection with the capsule holder may be obtained by a transfer of rotational momentum from the water injection head via the capsule and/or directly to the capsule holder. In this case, the transmission system of the rotary drive assembly is directly connected to the upper side of the filling head, in particular to the rotary joint part of the filling head.

The device of the invention can receive capsules made of rigid, semi-rigid and/or soft materials. The capsule may be made of materials such as plastic, aluminum, cellulose-based materials or other biodegradable materials, and combinations thereof. Preferably, the capsule has a closed pierceable wall (e.g. a membrane) comprising at least an annular portion for being pierced, which is peripheral with respect to the axis of rotation of the capsule when the capsule is in place in the device. The wall may form a sealing membrane covering a cup-shaped body which receives the food substance to be brewed. The capsule may be formed with a body that is stiffer than the membrane to be pierced. The capsule is preferably closed in an airtight manner. The inner volume of the capsule not occupied by the substance may advantageously be filled with a protective gas (e.g. nitrogen). The capsule has a layer of material, such as an aluminium or EVOH layer, which has gas barrier properties.

In one embodiment, the system may comprise valve means disposed downstream of the opening means of the at least one liquid delivery outlet. The valve enables the pressure inside the capsule to be controlled by opening at a prescribed pressure threshold of the liquid exerted on the valve. The valve means may comprise an annular closing ring and resilient means for resiliently engaging the ring onto a peripheral portion (e.g. rim) of the capsule when closed. The valve may be designed to provide an adjustable value of its closing load. The valve means may be used to control the pressure in the capsule and thus the release of centrifuged liquid from the capsule. In particular, the valve means may also prevent small particles (e.g. coffee fines) from accumulating at the outlet of the capsule and avoid clogging or at least significantly reducing the flow rate. It should also be noted that the valve provides more froth or foam in the liquid. In particular, the higher the load on the valve, the more froth or foam is formed.

The invention also relates to a method for preparing a food liquid from a food substance contained in a single-use capsule by passing water through the substance, the method comprising:

the capsule is driven to centrifugally rotate while water is introduced into the capsule,

passing water through the mass to form a food liquid,

piercing at least one liquid delivery outlet in the capsule,

wherein the piercing is obtained at least partly by the effect of the centrifugal force of the liquid exerted in the capsule due to the centrifugation.

The capsule may be a hermetically sealed capsule comprising ingredients such as ground coffee, instant coffee, tea leaves, instant tea, cocoa, chocolate, cheese, sweeteners and any combination thereof, which may be kept under protected atmospheric conditions for a long period of time. The capsule is opened when used in the device.

According to an aspect of the method, the at least one liquid delivery outlet is obtained by piercing at least a peripheral portion of the capsule. In particular, the piercing of the capsule is performed by the outward deformation of the peripheral portion of the capsule against the piercing elements. The piercing element may be part of the apparatus of the present invention. More specifically, the peripheral portion is part of a sealing membrane of the capsule. The membrane may be formed of a thin plastic and/or aluminum material.

In a preferred embodiment of the invention, the opening of the at least one outlet is performed at least partially when the peripheral portion of the capsule is deformed outwards by the action of the internal pressure of the centrifuged liquid at the peripheral portion of the capsule. The at least one liquid delivery outlet may be obtained by piercing a peripheral portion of a membrane of the capsule. More preferably, several outlet openings are opened in the peripheral part of the membrane of the capsule. Thus, the portion of the membrane may be pierced against a set of piercing elements such as needles, pyramids, and/or blades. The liquid may also be forced in the direction of the peripheral portion by the capsule side wall widening in the direction of the peripheral portion of the perforable membrane.

In a possible embodiment, the set of piercing elements is distributed along a substantially circular path, so as to form a piercing crown projecting at the periphery of the injection head. The piercing crown is configured to engage a peripheral region of the perforable membrane. More specifically, the piercing crown is part of the rotational engagement member of the injection head. The crown may be integral with the component as part, for example may be moulded as a single piece with the component.

The capsule can be held during centrifugation by its clamped peripheral edge, which is clamped closed around the capsule by the injection head and the capsule holding means. During the closing of the device with respect to the capsule, the piercing element may be in contact with the sealing membrane or may be slightly spaced from the sealing membrane. The contact with the sealing film may for example form a pre-weakening of the sealing film, such as an imprint (imprint) or a small perforation. As the liquid is centrifuged in the capsule, the pressure of the liquid is exerted on the periphery of the inner surface of the sealing membrane, which is therefore expanded or deformed in the direction of the piercing elements, so as to be pierced against the piercing elements (for example against the piercing crowns). Of course, pre-weakening of the perforable membrane can be avoided by the piercing element only being in contact with the membrane or being kept at a controlled distance before the capsule is centrifuged in the device.

The sealing membrane may be flexible or somewhat rigid, depending on the material. The membrane may have a concave shape in its initial set state and may form a convex shape in response to centrifugal separation pressure. In this case, the material may be made of, for example, a thermo-formed or injection-formed plastic. Preferably, the membrane is thin and flexible to deform snugly against the piercing element. The system may no longer require a filter, as solid particles of the substance may be prevented from exiting the capsule at the interface between the edge of the pierced outlet and the surface of the piercing element. One advantage is that the structure of the capsule is greatly simplified by fewer parts (no filter is required in the capsule) and therefore the manufacturing costs can be significantly reduced.

According to one possible aspect of the process of the invention, the water is introduced into the capsule through an opening of less than 5mm, preferably between 0.9 and 2.9 mm. As mentioned before, a sufficiently small water inlet in the capsule is preferred to reduce the internal pressure at the inlet side of the capsule and thus avoid liquid leakage problems.

Preferably, water is introduced into the center of the capsule after the water inlet has been pierced at the center of the capsule.

In one embodiment, the liquid delivered from the capsule opens the valve when a certain pressure of the released liquid is exerted on the valve by the centrifuged liquid. The valve also regulates the flow of liquid and it reduces the risk of small-sized particles (e.g. coffee fines) clogging the small outlet provided in the capsule, in particular at relatively low pressure values.

The valve may preferably consist of at least a part of the device. The valve means may be formed by at least one engaging part of the device which is moved relative to a engaging part of the capsule or device under the action of the pressurized liquid to form a thin annular compound channel for the liquid. The compound channel also forms a liquid jet with a relatively high velocity that impinges on the wall of the device. Thus, a large amount of foam may be formed both due to the restriction created by the valve means and by the liquid impinging on the impact surface of the device at a relatively high velocity during centrifugation. The restriction created by the valve means may vary in magnitude depending on the amount of pressure exerted on the valve means by the centrifuged liquid. In one possible embodiment, the valve means can be calibrated or adjusted to selectively open the liquid passage through the device at a pressure threshold in the capsule.

The system of the invention thus provides a solution for preparing a food liquid, wherein a controlled release of the food liquid can be performed. For example, the release of liquid may be delayed until a certain pressure is exerted on the peripheral portion of the capsule, which is then pierced against the external protruding element of the device. The delayed opening of the capsule enables an improved interaction between the water and the substance contained in the capsule and also enables a filtering of the liquid to be obtained by the constraint formed between the piercing outlet of the device and the piercing element. In this case, the capsule may have a very simple structure and may be discarded after use, for example to facilitate destruction or recycling.

For coffee, for example, it may be advantageous to optimize the interaction of water and ground coffee particles to obtain a good extraction of coffee and aroma compounds. Furthermore, the foam or crema can be improved due to the shear stress generated by the pressure release and the constraint formed in a dynamic manner between the outlet of the capsule and the piercing element during the centrifugation operation.

The liquid delivered from the capsule can also be filtered by dedicated filtering means provided in the capsule. This configuration has an advantage in that the apparatus is simplified; the filter does not need to be cleaned as it is discarded after a single use with the capsule.

The invention also relates to the device itself as described in this application.

The term "food liquid" is used herein in a broad sense and includes: cooking liquids such as soups or sauces, liquid chocolate such as coffee extract (obtained from ground and/or instant coffee powder), milk (obtained from powder and/or liquid concentrate), tea extract (obtained from instant and/or tea leaves), etc., or nutritional liquids such as infant formula and combinations thereof.

The term "brewing" or "brewed" should not be construed narrowly as extracting liquid under pressure from an incompletely soluble substance (e.g. ground coffee or tea leaves), but should be construed in a broader sense as encompassing the interaction process of a food substance and a liquid (preferably water) including extraction, infusion, adsorption, dissolution, dilution, dispersion, mixing, emulsification, foaming, and the like.

The term "piercing" is to be understood in its broadest sense and includes mechanical processes such as perforating, cutting, breaking and/or tearing to provide a through-going opening in the capsule wall.

Drawings

Further technical features of the present invention will be apparent from the following detailed description of the drawings.

FIG. 1 is a top perspective view of a sealed capsule of the system according to the present invention;

FIG. 2 is a bottom perspective view of the capsule of FIG. 1;

FIG. 3 is a perspective view of the beverage production device of the present invention;

figure 4 is a cross-sectional view of a beverage production device with a capsule inside;

figure 5 is a detailed cross-sectional view of the device with the capsule inside before the capsule is opened by the device;

FIG. 6 is a detailed cross-sectional view of the device with the capsule inside after piercing of the capsule;

fig. 7 is a perspective view of the junction of the water injection head of the device.

Detailed Description

As shown in fig. 1 and 2, a preferred disposable capsule 1 of the present invention comprises a disc-shaped body 2, a sealing foil or film 3 being sealed to the disc-shaped body 2. The sealing foil 3 is sealed to the peripheral edge 4 of the body in a sealing ring-shaped portion 5. The peripheral edge 4 may extend outwardly to form a small annular seal of about 2-5 mm. The disc-shaped body comprises a bottom wall 6 and side walls 7, which preferably expand towards the large open end of the body opposite the bottom wall. The disc-shaped body is preferably rigid or semi-rigid. The disk-shaped body may be formed of a food grade plastic (e.g., polypropylene) or an aluminum alloy or a composite of plastic and aluminum alloy with a gas barrier layer (e.g., EVOH and the like). The sealing foil 3 may be made of a thinner material, for example a plastic laminate also comprising a shielding layer or an aluminium alloy or a combination of plastic and aluminium alloy. The sealing wall typically has a thickness of, for example, between 50 and 250 microns. The sealing foil member may be pierced in order to form a water inlet and a beverage outlet as will be explained later.

Preferably, the capsule forms a rotationally symmetrical shape around the central axis a. It should be noted, however, that the capsule does not necessarily have a circular cross-section about the axis a, but may take another form, for example a square, rectangular or other polygonal form.

A system comprising the capsule of the invention and a beverage preparation device is shown in fig. 3 to 7 and will now be described.

The system comprises a capsule 1 as described hereinbefore and a beverage preparation device 23. The device has a module 24 into which the capsule can be inserted. The capsules contain food substances for brewing and are removed from the module after use for disposal (e.g. as waste or for recycling of organic and inorganic raw materials). The module 24 is in fluid communication with a water supply, such as a water reservoir 25. A fluid delivery device, such as a pump 26, is disposed in the fluid circuit 27 between the module and the water supply. A water heater 28 is also provided to heat the water in the fluid circuit before it enters the module. The water heater may be inserted into the fluid circuit to heat the fresh water from the reservoir. Alternatively, the water heater may be arranged in the water reservoir itself, in which case the water reservoir becomes a water boiler. Of course, water may also be taken directly from the domestic water supply via a water plug connection. The device may further comprise control means and activation means (not shown) for activating the beverage preparation method.

Water may be fed into the module 24 at low pressure or even at gravity pressure. For example, a pressure of between 0 and 2bar above atmospheric pressure at the water inlet of the module is conceivable. Water at a pressure above 2bar may also be delivered if a pressure pump, such as a piston pump, is utilized.

Brewing module 24 may include two main capsule enclosing subassemblies 29, 30; mainly comprising a water injection subassembly or head and a liquid receiving subassembly comprising a capsule holder. These two subassemblies form the positioning and centering means for the capsule in the device.

The two subassemblies are closed together, for example by means of a bayonet-type connection system 31, to enclose the capsule therein. The liquid receiving subassembly 30 comprises a liquid conduit 32, which liquid conduit 32 protrudes, for example, on one side of the subassembly in order to guide the liquid centrifuged from the capsule to a serving container (such as a cup or glass). The liquid conduit communicates with the liquid receptacle 33 to form a U-shaped or V-shaped annular cross-section around the capsule holder formed by the rotary drum 34 into which the capsule is inserted, as shown in fig. 4. The liquid receptacle 33 defines a collection chamber 63 for collecting liquid as will be described later. Below the liquid receiving subassembly 30 there are means for driving the capsule receiving cartridge 34 in rotation inside the subassembly.

The drive means preferably comprises a rotary motor 40 which may be powered electrically or pneumatically.

The water injection subassembly includes a water inlet side that includes a water inlet 35 that communicates upstream with the water fluid circuit 27.

The rotary drum 34 is formed as a hollow capsule holder with an internal cavity 36 complementarily shaped to receive the capsule. The rotary cylinder 34 itself is axially extended by a rotary shaft 37, which rotary shaft 38 is held in a rotary relationship with respect to an outer base 38 of the liquid receptacle 33 by means of a rotary guide 39, such as a ball bearing or a needle bearing. Thus, the rotary cylinder is designed to rotate about the intermediate axis I, while the outer base 38 of the receptacle is fixed relative to the device. A mechanical coupling may be provided at the connection between the rotating shaft 37 of the cartridge and the shaft 42 of the motor 40.

With respect to the water injector subassembly 29, it comprises a centrally arranged water injector 45, which is fixed with respect to the longitudinal axis I of the device. The injector comprises a central tubular part 46 for conveying water from the inlet 35 to a water outlet 47, the water outlet 47 protruding into the enclosure 14 of the capsule 120. The water outlet is formed by a piercing means 48, such as a sharp tubular tip, which is capable of forming a piercing hole through the closing foil of the capsule.

A rotary joint 49 is mounted around the water injector. The engagement portion 49 has a central hole for receiving the water injector and a rotation guide means (e.g. a ball bearing or needle bearing 50 inserted between the portion 49 and the water injector 45).

The capsule engagement sub-assembly 29 may also include a tubular shroud 62, which shroud 62 projects into the annular chamber 63 of the liquid receiving sub-assembly 30 when the two sub-assemblies are closed relative to each other around the capsule. The tubular shroud 62 forms an impingement wall for the centrifuged liquid exiting the centrifugation capsule. The portion 62 is preferably secured to the subassembly 29. The subassembly also includes a grip portion 64 that facilitates attachment to the liquid receiving subassembly 30. The gripping portion 64 may have a knurled outer peripheral surface for gripping. The grip portion may be secured to the fixed base of the subassembly 29 by screws 67.

This part can of course be replaced by a lever mechanism or similar gripping means.

According to an important aspect of the invention, the rotary joint comprises a piercing element 53 at the periphery of the portion. More specifically, the piercing element is formed by a small element protruding from the lower surface of the joint. The piercing elements are preferably distributed along a circular path so as to form piercing crowns on the surface of the engaging portion.

In a preferred embodiment, the piercing element is a solid (i.e., non-hollow) element having a larger base and a narrow tip. For example, the elements are small truncated pyramids. When a sufficient amount of liquid pressure is built up at the periphery of the membrane as shown in fig. 6, the membrane 3 is deformed outwards in the direction of the piercing element 53. Due to the widening/expanding shape of the side wall 7 of the capsule, the liquid is forced to rise (direction F) through the substance in the capsule and press on the peripheral portion of the membrane 3, causing the membrane to be pierced against the element 53. The element is a solid element, the outlet being formed by a small gap between the edges of pierced holes contained in the membrane and the surface of the pierced element fitting within these holes. Thus, filtration of the liquid may be performed between the element and the membrane. No special filter is required in the capsule.

Thus, the piercing members are arranged at the periphery of the wall 55, preferably evenly distributed to provide several outlet openings in the capsule for several streams of centrifuged liquid leaving the capsule.

As shown in fig. 7, a small flow distribution slit 71 may be provided downstream of the injection head. An annular collection recess 57 may be provided between the element 53 and the slot 71 to provide a more uniform volumetric distribution of liquid. These slots may be provided through the clamping periphery 52 of the engaging portion, which provides a clamping force acting on the sealing edge 4 of the capsule. The slots may be dimensioned such that a plurality of beverage jets is generated which impact centrifugally at a relatively high velocity on the impact wall 62 of the device. For example, each slot may have a size from 0.05 to 1.0 mm. The number of slots may vary. For example, between 4 and 200, preferably between 30 and 100, slots may be provided.

According to an alternative not shown, the piercing element 53 may be hollow to allow the passage of liquid therethrough. However, since the hollow element will be more easily clogged by small solid particles (e.g. ground coffee particles), there is a tendency to provide a separate filter in the capsule to reduce this risk.

According to an aspect of the invention, the water injection subassembly 29 further comprises a valve system for controlling the flow of liquid discharged from the apparatus. The valve system may be arranged on a capsule rotary engagement portion in the form of an annular engagement portion biased under the force of resilient loading means, such as a spring. The annular engaging portion comprises an urging peripheral surface exerting a closing force on the peripheral edge 4 of the capsule so as to be able to restrict the flow of liquid under the force of the elastic loading means. The surface may be tapered or "V" shaped to increase the sealing pressure in localized areas. The joint also includes an inner base. The spring-loading means is inserted into a space between the base portion and the reaction force portion of the engagement portion. Thus, in the seated state, the engagement portion of the valve system remains closed on the edge of the capsule under the compression action of the resilient loading means.

As mentioned above, a connection means 31 is provided for the relative connection of the two subassemblies 29, 30. For example, a small pin 65 is provided on one side of the tubular surface of the water injection subassembly 29 that can engage a side locking aperture 66 located on the tubular surface of the liquid receiving subassembly 30. Thus, the connection between the two subassemblies may be performed by a rotational angular or helical closing motion to enable the pin to engage the elongated aperture 66. Of course, other connection means are conceivable instead of the bayonet-type connection means. For example, a threaded device or a translating closure device may be envisaged by the person skilled in the art.

The capsule system of the present invention operates substantially according to the following principle. The capsule device is opened by moving the two sub-assemblies 29, 30 relative to each other, for example by separating the bayonet type connection and separating the two sub-assemblies 29, 30. Thus, a single-use sealed capsule 1 containing a food substance may be inserted into the apparatus, for example, disposed in a cavity of the rotary drum 36. The capsule can be installed in the device while the capsule is hermetically closed by the sealing foil 3. The device is then closed by the sub-assembly 29 reconnected to the sub-assembly 30 and locked by the connection means. In the locked state, the capsule is opened by a water injector piercing the sealing foil of the capsule, and the water injector guides itself through the water inlet 35 of the capsule. During closing, the membrane may be weakened at the periphery of the sealing foil by the outlet piercing member 53. Weakening of the film may include forming small indentations or small through-holes in the film. Water can thus be introduced into the capsule via the central water injector 45. A vent may be formed in the injection subassembly to allow gas to escape from the capsule while water is being introduced. The capsule can be driven in rotation by activating the rotation motor 40. The start-up of the centrifugation operation may be performed at the same time as the injection flow of water starts to be introduced into the capsule, or later or earlier than the start of the water injection operation.

For example, it is advantageous for brewing ground coffee to allow water to be injected into the capsule within a few seconds before the centrifugal separation operation is initiated by rotating the capsule. Thus, water may penetrate into the coffee before the liquid is centrifuged, thereby avoiding that the coffee area remains dry.

The centrifugation is performed by rotating the capsule around a central axis of rotation I of the device, which is preferably aligned with the central axis a of the capsule. The rotation speed is preferably 1000 to 16000 revolutions per minute (rpm), more preferably 1500 to 10000 rpm. A control unit may be provided in the device to set the rotational speed in dependence of the liquid to be brewed and/or the properties of the substance in the capsule. The higher the rotation speed, the higher the pressure exerted on the peripheral wall of the capsule and the more material compacted on the side walls and perforable membrane of the capsule. It is important to note that higher rotational speeds promote brewing of coffee extracts with lower solids content (solid content) because the residence time of the liquid in the coffee bed is shorter. A lower rotation speed provides a higher strength (coffee solids content) of coffee, because the residence time of the liquid in the capsule is longer. The brewing is performed in the capsule by water traversing the substance, thereby providing extraction or partial or complete dispersion or dissolution of the substance. In the first brewing stage, liquid is not allowed to leave the capsule, because the outlet is not sufficiently open or even no outlet has been provided in the membrane.

Under the effect of the centrifugal force, the substance (e.g. coffee powder) tends to compact itself radially against the peripheral wall 7, 17 of the enclosure of the capsule, while water is forced to flow through the substance. This causes the material to both become dense and fully wetted with water. Due to the high speed rotational movement of the capsule, centrifugal forces are automatically and evenly applied to the accumulated substance. Thus, the distribution of water is more uniform compared to conventional methods using a pressure pump to apply pressure in the capsule. Thus, there is less risk of a preferential flow path through the substance, which may result in areas that are not properly wetted and therefore not properly brewed, dispersed or dissolved. For ground coffee powder, the liquid reaching the inner side wall of the capsule is a liquid extract.

As the liquid pressure increases at the capsule membrane, the liquid extract is forced to flow upward along the inner surface of the capsule side wall. The widening of the side walls 7 of the capsule promotes the upward flow of the liquid in the capsule in the direction of the openings. Thus, the membrane 3 is deformed and thus pierced against the piercing element 52. Thus, the centrifuged liquid is allowed to pass through a plurality of outlet openings 18 provided in the capsule, e.g. through the lid 8. This results in a second transfer phase during which liquid is released through the pierced outlet.

As also previously described, the outlet openings also provide flow restrictions that affect the interaction of the water with the substance and the formation of foam or froth on the beverage. The flow restriction creates a shear stress and thus a foam or crema is created. A portion of the gas contained in the capsule may become entrained in the liquid and provide a large number of small bubbles in the liquid due to the pressure release after the flow restriction.

The delayed opening of the capsule membrane depends on various parameters, such as the centrifugation speed, the characteristics of the membrane (tear strength, thickness), the shape of the piercing element, etc.

The system capsules of the present invention provide superior brewing results with solids content over conventional systems. These results can be easily reproduced between capsules. Unexpectedly, the crema also improved significantly into a greasy body, which had a more stable and thicker texture.

Of course, the invention may encompass numerous variations that are included within the scope of the following patent claims.

Claims (17)

1. A liquid food preparation system for preparing a liquid food from a food substance in a capsule by passing water through the substance, the liquid food preparation system comprising a device and a capsule removably insertable into the device, the device comprising a water injection head for injecting water into the capsule and a capsule holder for holding the capsule in the device,

characterized in that said liquid food preparation system comprises:

a water injector provided as part of the water injection head for introducing water into the capsule,

means for driving the capsule for centrifugal separation, and

in the liquid food preparation system, the opening means are configured relative to a capsule located in the device to form at least one liquid delivery outlet in the capsule in response to centrifugal forces of liquid exerted in the capsule.

2. System according to claim 1, wherein the device comprises at least one opening means for providing at least one liquid delivery outlet in the capsule, which is disposed in an offset position with respect to the central axis of the capsule holder.

3. The system of claim 2, wherein the opening device comprises a set of piercing elements distributed along a substantially circular path about the central axis.

4. The system of claim 2, wherein the opening element forms a piercing crown at a periphery of the rotating engagement member.

5. System according to claim 3 or 4, characterized in that the opening means form a truncated pyramid, a needle and/or a knife edge.

6. System according to any of the preceding claims, wherein the injector comprises a piercing member.

7. System according to claim 6, wherein the piercing member is arranged as a hollow piercing tube for injecting water into the center of the capsule.

8. System according to claim 7, wherein the diameter of the piercing member is less than 5mm, preferably between 0.9 and 2.9 mm.

9. System according to any of the preceding claims, wherein the capsule comprises a pierceable membrane, the at least one delivery outlet being formed in the pierceable membrane.

10. The system of claim 9, wherein the capsule is airtight.

11. A method for preparing a food liquid from a food substance contained in a single-use capsule by passing water through the substance, the method comprising:

driving the capsule to centrifugally rotate while introducing water into the center of the capsule,

passing water through the mass to form a food liquid,

piercing at least one liquid delivery outlet in the capsule,

wherein the piercing is effected at least partly by the effect of liquid centrifugation exerted in the capsule due to centrifugation.

12. Method according to claim 11, wherein the peripheral portion of the capsule is pierced by the action of the centrifugal pressure.

13. Method according to claim 12, wherein piercing is performed by deforming the peripheral portion of the capsule outwards against piercing elements.

14. The method of claim 11 or 13, wherein the peripheral portion comprises a portion of a perforable membrane of the capsule.

15. Method according to claim 14, wherein liquid is forced towards the peripheral portion by a side wall of the capsule, which side wall widens towards the peripheral portion of the perforable membrane.

16. Method according to claim 14, wherein the perforable membrane is sealed onto a flange-like rim of a cup-shaped body of the capsule containing the substance.

17. Method according to any one of claims 11 to 16, wherein water is introduced into the capsule through an opening of less than 5mm, preferably between 0.9 and 2.9 mm.