Patent Description:
The preparation of a beverage by using centrifugation is known. The principle mainly consists in providing a beverage ingredient in a receptacle, feeding liquid in the receptacle and rotating the receptacle at elevated speed to ensure interaction of the liquid with the ingredient while creating a gradient of pressure of liquid in the receptacle; such pressure increasing gradually from the centre towards the periphery of the receptacle. As liquid traverses the coffee bed, extraction of the coffee compounds takes place and a liquid extract is obtained that flows out at the periphery of the receptacle.

<CIT> describes a possible example of a device using such principle wherein the receptacle is a capsule containing beverage ingredients. Hot water is fed in the centre of the capsule via a water interfacing part comprising a water injector aligned in the rotation axis. The receptacle is held in a capsule holder which is rotated by means of a rotary motor. Both the liquid interfacing part and the capsule holding part are mounted along ball bearings. The beverage is extracted from the capsule by a plurality of peripheral needles that creates openings through a lid of the receptacle. As the capsule is centrifuged about its rotation axis, hot water passes through the beverage ingredient, interacts with it to produce a liquid extract and the resulting liquid extract traverses, under the effect of the centrifugal forces, the peripheral openings and is projected against an impact wall of the collector. The liquid extract, thus constituting the beverage, is then drained through a beverage duct of the device and collected into a recipient such as a cup.

<CIT> and <CIT> further describe a beverage preparation device wherein a flow restriction is created downstream of the receptacle, in particular a capsule, for example, by a valve system which opens or enlarges under the pressure created by the centrifuged liquid leaving the receptacle. The higher the rotational speed, the more the valve opens or enlarges. The valve system can be formed by a mobile restriction part of the device which is elastically urged against a rim portion of the capsule.

The present invention aims at providing such centrifugal beverage production device with means modifying the characteristics of a beverage produced.

In particular, when producing a coffee beverage, it can be desired that the produced coffee beverage, after being dispensed in a beverage receptacle, presents a so-called "crema" on its surface. However, it can also be desired that the coffee beverage is also produced with less or little 'crema' or even with substantially no 'crema' at all. Therefore, the flexibility to adjust the beverage characteristics, more particularly, the amount of 'crema' in the coffee beverage is desired.

This object is solved by means of the features of the independent claim. The dependent claims develop further the central idea of the invention.

According to one aspect of the invention, a device for preparing a beverage from a substance contained in a capsule, comprises:.

The beverage draining means comprise at least one valve. Furthermore, at least one external valve operating means is arranged for controlling the state of the valve in order to modify the flow resistance of the beverage draining means. "External" is to be understood such that such valve operating means apply a force from outside the beverage draining means. This is in contrast to forces which the flowing beverage inside may produce against the inner wall or other elements inside the beverage draining means.

The external valve operating means may be arranged to control the state of the valve such that the higher the rotational speed, the higher the closing force of the valve. The closing force will typically act against the forces generated by the centrifuged beverage against the valve member, such that the valve state will finally be in an equilibrium state.

The flow rate of the beverage is a function of the rotational speed. Thus, a flow rate control may be implemented which controls the rotational speed such that a desired flow rate is achieved. The flow rate control may comprise a flow rate sensor feeding back the actual flow rate. As according to one aspect of the invention, the flow resistance of the beverage draining means is a function of the rotational speed, thus also the flow resistance of the beverage draining means is a function of the flow rate control. The higher the flow rate, the higher the rotational speed and thus the higher the flow resistance of the beverage draining means.

According to an aspect the external valve operating means control the closing force, but not the absolute state of the valve (which is the result of an equilibrium of forces as discussed above).

In other embodiments, the external valve operating means may control the absolute state of the valve ("position control", e.g. by increasing the closure force until the absolute state is reached).

The valve may be controlled such that the flow resistance is higher at a first rotational speed than at a second rotational speed, wherein the second rotational drive speed is lower than the first rotational speed.

The first and second rotational speeds are not related to a particular sequence of rotational speeds and may be applied selectively for preparing a beverage depending on the characteristics of extraction desired.

The valve operating means may control the state of the valve such that the flow resistance of the beverage draining means increases in at least one subrange or the total of the range of the adjustable rotational speed.

The valve operating means may control the state of the valve such that.

When the rotational speed is higher than the threshold rotational speed, the valve operating means may control the state of the valve such that the valve.

The beverage draining means may comprise a section which is arranged to be rotatable together with the capsule holder, and
wherein the at least one valve is arranged in the rotatable section of the beverage draining means. In particular, the rotatable section may be a liquid interfacing part of the device arranged for supporting the valve.

The external valve operating means may comprise a valve member, e.g., a valve compressing member, which is arranged to be displaced in a flow resistance increasing direction by centrifugal forces when the rotatable section of the beverage draining means and thus the mass of the valve member (or another mass connected to the valve member) is rotated.

The valve member, e.g., valve compressing member, may be arranged to be displaceable in rotation and/or translation. The displacement of the valve member is effective between a state of low (or substantially no) flow resistance to a state of higher flow resistance of the valve.

The valve may comprise restoring force means biasing the valve towards the state of lower flow resistance. Preferably, the restoring force means is arranged to act against the valve member.

The restoring force means may be for example a spring element arranged to bias the valve towards the state of lower flow resistance. The spring element can be external to the walls of the beverage draining means. Alternatively, the restoring force means may be an integral resilient wall part of the beverage draining means arranged to engage the valve towards the state of lower flow resistance.

Preferably, the restoring force means (e.g. spring element) forces the valve to return to a state of lower flow resistance when the rotational speed is lower or equal than a threshold rotational speed. On the contrary, when the rotational speed is above the threshold, the restoring force means does not provide a sufficient effort on the valve to return it to the state of lower flow resistance.

Preferably the restoring force means (e.g. spring element) is arranged to oppose the displacement of the valve member toward the state of higher flow resistance. Therefore, in absence of rotation or at a lower rotational speed, the restoring force means maintains the valve member in a position in which the valve is maintained open.

The valve may comprise a flexible membrane arranged to vary the free cross-section of the beverage draining means when displaced. This action of the flexible membrane thereby determines the flow resistance of the beverage draining means.

The device may comprise capsule identification means and/or user interface means. The means for operating the state of the valve may be designed to control the state of the valve based on information provided by the capsule identification means and/or user interface means.

A further aspect of the invention relates to a method for preparing a beverage from a substance contained in a capsule, the capsule being placed in a beverage production device,.

The invention also provides a beverage device for preparing a beverage by centrifugation, from a capsule rotated in the device, comprising:.

Preferably, the external valve operating means are arranged or controllable according to these two different states of the valve in a manner that in the second state of the valve, the rotational speed/speeds is/are set at higher value/values than in the first state of the valve.

In a mode, the valve comprises at least one valve member, e.g., a valve compressing or closing member, arranged to be movable from the first state towards the second state of the valve by the action of the centrifugal force which exerts on the valve member. For example, the valve member can be a pivot member, pivotable by the action of the centrifugal forces for pressing on at least one soft, elastic membrane which is arranged for restricting the flow opening cross-section of the valve when such pressing action is engaged. The pivot member preferably comprises at least one mass of inertia, e.g., a metal piece having a density higher than <NUM>, preferably higher than <NUM>.

According to an aspect, the invention relates to a beverage device for preparing a beverage by centrifugation, from a capsule rotated in rotating parts of the device and containing ingredients comprising:.

wherein the external operating means comprises at least one valve actuation member operatively arranged to be movable under the effect of the centrifugal forces in a manner to deform or move the deforming or moving part of the valve in the direction of a reduction of the beverage flow cross-section of the valve when the rotational speed of the rotating parts increases.

In particular, the valve actuation member can be arranged on one of the rotating part, preferably on the liquid interfacing part, so as to pivot or translate as a result of or under the action the centrifugal forces applied thereon.

The device can comprise a biasing means, such as a spring element, arranged with the valve actuation member to apply a biasing force on the valve actuation member which is opposed to the direction corresponding to a reduction of the beverage flow cross-section of the valve.

Preferably, the biasing means is configured such that when the rotational speed of the rotating parts is below or at a threshold value, the valve actuation member takes a first state in which the beverage flow cross-section of the valve is enlarged or open and, when the rotational speed of the rotating parts is above the threshold value, the valve actuation member takes a second state forcing a reduction of the beverage flow cross-section of the valve compared to the enlarged or open position.

It should be noted that in the second state, the valve may take different relative positions as to the reduction of the flow cross section that essentially depends on the rotational speed and the pressure of beverage acting on the valve.

The moving or deforming part of the valve can be an elastic membrane. The elastic membrane can be moved and/or deformed as a response to the movement of the valve actuation member combined to the pressure of the beverage flow through the valve and contacting the membrane. In alternatives, the moving or deforming part of the valve can be a portion of elastically deformable conduit guiding the flow of beverage. The elastically deformable conduit can be deformed, in particular by its cross section narrowing, as a response to the movement of the valve actuation member combined to the pressure of the beverage flow through the conduit.

The invention also relates to a system comprising a beverage preparation device as aforementioned and a capsule containing beverage ingredients.

Further features, aspects and advantages of the invention shall now be described with reference to the figures of the enclosed drawings, wherein.

The principles of a centrifugal beverage device shall now be described with reference to <FIG>. The device <NUM> of the invention generally comprises as known `per se' a centrifugal brewing unit <NUM> for receiving and centrifuging a receptacle such as a removable capsule <NUM>. The centrifugal brewing unit <NUM> is designed for preparing a beverage such as coffee, from both a beverage ingredient contained in the capsule <NUM> and water injected in the capsule <NUM>. The injected water interacts (such as by brewing or mixing) with the beverage ingredient and, by virtue of the centrifugal forces, a beverage extract is obtained which is forced to leave the capsule <NUM> at its periphery. The unit <NUM> is placed in liquid communication with a liquid supply line <NUM> intended for supplying a heated liquid, preferably water, from a reservoir <NUM> to the unit <NUM>. The liquid is circulated through the line <NUM> by a pump <NUM>. The pump <NUM> can be of any suitable type such as a piston pump, a diaphragm pump, a gear pump or a peristaltic pump, for example. A heater <NUM> is provided along the liquid supply line to heat the liquid at a temperature above ambient temperature. The temperature may vary depending on the beverage to be extracted. For instance, for coffee, water can be heated between about <NUM> and <NUM> degrees Celsius.

The brewing unit <NUM> comprises two rotating parts <NUM> connected together, in particular, a liquid interfacing part <NUM> and a holding part or capsule holder <NUM>. The two parts <NUM>, <NUM> are designed for holding the capsule <NUM> containing a beverage ingredient. The device <NUM> further comprises a rotational driving means <NUM> such as a rotary electric motor which is coupled to one of the rotating parts of the brewing module such as the holding part <NUM> via a coupling means. The rotating parts are arranged in closure, i.e. are connected together by connections at least during rotation in such a manner that these parts <NUM>, <NUM> rotate together about an axis A with the capsule <NUM> during centrifugation. It should be noted that the capsule holder <NUM> may take various configurations and may not necessary be completely separable from the first rotating part.

A control unit <NUM> is also provided to control the brewing operation, in particular, the rotational speed of the rotating parts <NUM> via the motor, the temperature of the liquid provided by the heater <NUM> and other operations such as the flow rate and amount of liquid supplied by the pump <NUM>. A flow meter <NUM> can be positioned in the flow liquid supply line to measure the liquid flow and provide input to the control unit <NUM>. As will be explained later, the control unit <NUM> may also receive information from a user interface <NUM> and/or a capsule identification system <NUM>. An example for such capsule identification system is a bar code reader <NUM> underneath the rim of the capsule <NUM>.

The liquid interfacing part <NUM> can comprise an injector <NUM> designed for supplying (e.g. injecting) a liquid like water in the (e.g. along the rotational center axis of the) capsule <NUM>. On its upper end, the injector <NUM> is in liquid communication with the liquid supply line <NUM>. Additional liquid control means such as a check valve may be provided upstream the injector <NUM>. At the periphery of the lower surface of the liquid interfacing part <NUM> is located a series of beverage extracting means <NUM> designed to perforate the inlet wall <NUM> of the capsule <NUM> in multiple zones to provide multiple beverage outlets for finally extracting the beverage from the capsule <NUM>. The peripheral outlets are thus created in the inlet wall <NUM> close to the rim of the capsule <NUM> where the centrifugal forces are the highest. Alternatively, it could be envisaged to provide outlets on the side wall of the capsule <NUM> or both on the inlet wall <NUM> and side wall of the capsule <NUM>. The beverage outlets could also be pre-made in the capsule <NUM> before insertion of the capsule <NUM> in the device <NUM>. It could also be that the rim of the capsule is formed as a plurality of outlets for the centrifuged liquid.

As can be seen in <FIG>, the means <NUM> for draining the beverage from the capsule comprise a first section 40a (when seen in the flow direction of the produced beverage) which is part of the rotating parts <NUM> of the beverage production device <NUM>. An interface <NUM> is provided at which the beverage is guided ("handed over") from the first rotating section 40a to a second section 40b of the beverage draining means <NUM>, which second section 40b is part of the static parts <NUM> of the beverage production device. The second (static) section 40b comprises a collector <NUM>, a collector exit <NUM> leading to a beverage production device outlet <NUM> arranged to guide the beverage into a beverage receptacle <NUM>. A rotational seal is provided between the rotating parts <NUM> and the static (stationary) parts <NUM> of the beverage production device.

According to the invention, means are provided for altering beverage characteristics by controlling the flow characteristics, such as the flow resistance of the beverage draining means <NUM>. Such means for changing the flow characteristics can be provided in the first (rotatable) part 40a and/or the second (static) part 40b of the beverage draining means. In the embodiments explained in the following these means for modifying the flow characteristics of the beverage draining means comprise a valve <NUM> in the particular mode of <FIG>, <FIG>.

The inventors have found out that modifying the flow characteristics, especially the flow resistance of the beverage draining means <NUM> has an impact on the characteristics of the produced beverage. when a coffee beverage is produced, increasing the flow resistance of the beverage draining means <NUM> causes a pressure drop which in turn promotes the production of the so-called "crema". The "crema" <NUM> will actually occur when the beverage is dispensed in the beverage receptacle <NUM> ("in-cup crema").

<FIG>, <FIG> show an embodiment in which such flow characteristic modifying means comprise a valve <NUM> arranged in the rotatable first section 40a of the beverage draining means <NUM>. In the example such rotatable first section 40a and thus the valve <NUM> are arranged within the liquid interfacing part <NUM> in which also the injector <NUM> is arranged.

The centrifuged beverage drained from the rotating capsule <NUM> is guided upwards (i.e. in a direction substantially perpendicular or inclined radially outwards when seen in the beverage flow direction) to the inlet wall of the capsule <NUM> through a first (e.g. essential axial or vertical) channel <NUM> of rotatable first section leading to the valve <NUM>. The axial or vertical channel <NUM> leads to a bend section <NUM> of the beverage draining means <NUM>. In the embodiment this bend section <NUM> forms an angle in the order of <NUM> degrees to <NUM> degrees and preferably <NUM> degrees to <NUM> degrees in the shown example.

The valve <NUM> according to this example is arranged in the bend section <NUM> of the first (rotatable) section 40a of the beverage draining means <NUM>. Downstream of the valve <NUM> (when seen in the beverage flow direction) a (e.g. essentially radial or horizontal) draining channel <NUM> is provided, which leads for example to the interface <NUM> shown in <FIG> and, thus, towards the second (static) section 40b of the beverage draining means <NUM>. The second static section 40b collects the beverage from the rotating parts and guide it to the receptacle <NUM>.

In the example shown in <FIG>, <FIG> the valve <NUM> comprises a membrane <NUM> which is mounted in a rotatable manner around a rotation axis <NUM>. It is to be understood that other valve designs are possible in which such membrane <NUM> or other valve element are arranged in a manner such that they are movable in translation (i.e. essentially linearly) and/or in combined rotation and translation.

The membrane may be made from silicone or any other food grade elastic material.

In the shown example the membrane <NUM> is mounted on a pivot means <NUM>, which pivot means <NUM> is mounted in a rotatable manner in the rotating part or liquid interfacing part <NUM> of the beverage production device <NUM> by means of the rotation axis <NUM>.

The pivot means <NUM> is one example for external valve state operating means. When rotated, the mass of the pivot means <NUM> (and any mass fixedly connected thereto) generates a centrifugal force, which one example of a force generated "externally", i.e. not internally (inside the beverage draining means) by flowing beverage. This external force is then used to control the change of the state of the valve <NUM>.

In <FIG>, <FIG> a least one additional mass <NUM> is shown which is attached (e.g., screwed) to the pivot means <NUM> to adjust and increase the centrifugal forces upon rotation.

The forces for closing the valve <NUM> (or reducing its flow cross-section) in the shown example are generated by centrifugal forces caused by the rotation of a mass of inertia including the pivot means <NUM>. When the capsule <NUM> and the rotating parts of the beverage production device are rotated, the centrifugal forces will cause a rotation or pivoting of the membrane <NUM> (against the clock in the shown example) around the axis <NUM> (which is an axis perpendicular to the rotation axis of the capsule and preferably perpendicular to a radial direction of the capsule in the transversal section of <FIG>), which rotation will cause an increase of the flow resistance of the beverage draining means. Again, the rotation of the membrane is just an example for a control of the valve state towards a state in which the valve increases the flow resistance of the beverage draining means <NUM>.

It is easily understood that the higher the rotational speed, the higher the centrifugal forces (essentially the centrifugal forces increase with the square of the rotational speed). Thus, the higher the rotational speed, the higher the closing force.

In order to make the valve <NUM> assume its state with lower flow resistance of the beverage draining means <NUM> (<FIG>), biasing means or restoring force means such as a helicoidal spring <NUM> are provided which bias the valve <NUM> towards the open state.

In the shown example, the radially inner end <NUM> of the helicoidal <NUM> spring is mounted offset to the rotation axis <NUM> by a distance d, such that the helicoidal spring <NUM> produces a torque in the clockwise direction in example of <FIG>, <FIG>.

In a preferred example, the helicoidal spring <NUM> or other biasing means are pre-stressed, such that in a first rotational speed range no state change of the valve <NUM> occurs until the centrifugal forces overcome the pre-stressing force of the helicoidal spring <NUM>. This will be further explained with reference to <FIG>.

It is important to note that according to the invention one or more valves <NUM>, <NUM>' with associated channels <NUM>, <NUM> of the beverage draining means may be arranged in the rotational part <NUM> of the beverage production device <NUM>. In one example three valves <NUM>, <NUM>' are arranged regularly spaced at an angular distance of <NUM>°. Of course the number of valves is not limited to three and can be <NUM>, <NUM> or <NUM>.

While <FIG> shows the state in which the valve <NUM> is in a state in which the flow resistance of the beverage draining means <NUM> is lower ("open state"), <FIG> shows the state in which the valve <NUM> is in the "closed" state. It is to be understood that "closed" does simply mean a state in which the valve <NUM> is in a state such that the flow resistance of the beverage draining means <NUM> is higher compared to the open state of <FIG>. However, even in the closed state the valve <NUM> is not completely shutting off the beverage draining means <NUM> or channel <NUM>. Rather, the valve will be in a state with higher flow resistance in which there is an equilibrium between the valve closing force (essentially the difference between the centrifugal force and the biasing force of the helicoidal spring <NUM>) and the force produced by the beverage coming from the channel <NUM> and acting on the valve.

In such closed state there will be a restricted cross section of the beverage flow in the area of the valve <NUM>. This beverage is typically pressurized also by means of the centrifugal forces. Thus, as shown in <FIG>, beverage may also flow in the closed state of the valve <NUM>. However, the pressure drop and the pressure upstream of the valve <NUM> are increased in the closed state of the valve <NUM> when compared to the open state of the valve <NUM>. It is thought that this increased pressure drop promotes the production of the crema in the finished beverage product.

As can be seen from <FIG> and <FIG>, the rim <NUM> of the membrane <NUM> is sealed to the parts, e.g. the bend section <NUM> and pivot means <NUM>, in which the channels <NUM> and <NUM> are formed. Thus, even in the open state of <FIG> of the valve <NUM>, beverage coming from the channel <NUM> cannot leak in the area of the valve <NUM>, but rather will still have to exit through the radial or horizontal channel <NUM> (the path of liquid is illustrated by arrows "L"). Due to this sealing of the rim <NUM> of the membrane <NUM>, the inner part of the membrane will be pushed by the pivot means <NUM> towards a closed state of the valve at high rotational speeds.

In the embodiment of <FIG>, <FIG> the membrane is moved by the hinged pivot means <NUM>. The hinged pivot means <NUM> is an example of external valve controlling means. "External" is to be understood such that such valve operating means apply a force from outside (relative to the beverage draining means). This is in contrast to internal forces acting on the beverage draining means and generated e.g. by the centrifuged beverage when acting against the inner walls or other elements inside the beverage draining means. The valve state according to the invention thus is a function of such control forces produced by the external valve control means.

In the embodiment of <FIG>, <FIG> the membrane is an example of a valve member which is part of the wall of the beverage draining means. The valve member can additionally or alternatively also be located within the beverage draining means.

In the shown example the membrane is an example of a flexible wall of the beverage draining means being part of the valve. However, the beverage draining means may present rigid walls, not deformed when changing the state of the valve. In such cases typically a movable valve member is provided within the walls of the beverage draining means.

In the embodiment of <FIG>, <FIG> the membrane is a movable part of the beverage draining means, acting against static parts of the beverage draining means. However, the valve may comprise more than one movable part.

In the embodiment of <FIG>, <FIG> the state of the valve is modified by changing the rotational speed of the capsule and the rotating parts of the beverage production device. In an example, thus the production of "crema" on top of a coffee beverage can be controlled by adapting the rotational speed during the beverage production process. The valve state can also be changed within the beverage production process such that e.g. the valve is only closed during a time period smaller than the entire beverage production process. the crema production can be "promoted at the end of the beverage production process. Thus, the duty cycle during which the valve is closed is at least one parameter of the beverage production process determining the amount and/or the quality of the crema.

Other embodiments are possible where the valve state is not modified by the rotational speed but, for example, by enabling/blocking means, which may selectively block the change of the valve state such that the valve state will remain in its current state even when the rotational speed is changed. The production of crema can be disabled or blocked independently of the rotational speed.

In the embodiment of <FIG>, <FIG> the valve state control means are purely mechanical. The valve control means in this embodiment can be viewed as "passive" elements as the driving force for the valve state change, i.e. the centrifugal force, "passively" is generated by the rotation. However, in other embodiments the valve control means may comprise an active actuator driving the modification of the valve state independently of the rotation.

For instance, the valve state control means may be at least one electrically-driven actuator such electro-mechanical, electrical, electromagnetic or induction actuator, such as a solenoid, electromagnet(s), electrical motor(s), and the like. In such case, the valve state may be controlled completely independently from the rotational speed. Rather, the valve state may be controlled at any suitable rotational speed. The switching of the valve state thus may involve electric signals send to the one or more electrically driven actuators.

Generally, the modification of the valve towards the flow resistance increasing state may be performed each time a beverage production process is run. Alternatively it may be performed selectively, i.e. dependent on a signal from a capsule identification device <NUM> of the beverage production device (involving the detection of an identification feature of the capsule) and/or a signal from a user interface <NUM> (touch screen, remote control, switches and the like) respectively communicating with the control unit <NUM>. Thus the valve state may be controlled depending on the type of capsule and/or the user's input.

Furthermore, in the embodiment of <FIG>, <FIG> the valve operating means do not involve a feedback mechanism in order to implement a feedback control. Especially when having an electric control, sensing means can be arranged on or within the beverage draining means sensing e.g. the pressure or the pressure drop of the beverage at the valve or alternatively the flow rate of the beverage.

The pressure or flow rate sensing means may also be arranged in the inlet tube <NUM> for the liquid supplied to the capsule <NUM>.

The control unit <NUM> may communicate with the valve state control means and can implement a feedback control of the state of the valve such that the sensed parameter (pressure, speed, of the beverage, etc.) can be controlled to a given nominal value. The nominal value can be dependent on the rotational speed, by providing a nominal value/rotational speed table, curve or function. The nominal value may develop (vary) along with an ongoing beverage production process.

<FIG> shows an example of a possible working curve of the pressure drop as a function of the rotation speed for a device of the invention. This is one example of a valve state control depending on or triggered (e.g. by centrifugal forces) on the rotational speed. As the backpressure generated by the valve, i.e. the pressure drop across the valve, is a function of the state of the valve, a zero backpressure in <FIG> is achieved in the open state of the valve.

In the shown example the valve is kept open, and the backpressure at the valve thus kept zero, between <NUM> rpm and a threshold rotational speed. At the threshold rotational speed the valve is switched in the closed state. It is to be understood that on the closed state the produced beverage may still pass the valve, although with increased flow resistance.

Above the threshold rotational speed, the flow resistance and thus the backpressure increases e.g. with the square of the increasing rotational speed. It is also possible that above the threshold rotational speed the backpressure remains constant or increases according to a different, e.g. linear function by correspondingly controlling the valve (e.g. by using a feedback control using backpressure sensing means).

It is also possible that the valve is controlled such that the backpressure increases starting from a zero-value rotational speed. However, keeping the valve open until the threshold rotational speed is reached has the advantage that after a beverage has been produced, the liquid delivery to the capsule is stopped and the capsule can be completely emptied by rotating it with a rotational speed between a zero-value rotational speed and the threshold rotational speed. Thus the capsule can be emptied while the valve in the beverage draining means is in the maximum opened state and the beverage draining means thus present the smallest flow resistance.

A second embodiment of the beverage production device of the invention is illustrated in <FIG>. The main difference lies in the beverage draining means comprising a circumferential valve <NUM> at the periphery of the rotatable liquid interfacing part. The valve comprises a continuous annular membrane <NUM>. The external valve operating means comprises a plurality of pivot means distributed along the circumference of the liquid interfacing part <NUM> (<FIG>). The pivot members are responsive to the centrifugal force when the part rotates and so arranged to control the state of the circumferential valve.

The membrane can be made of soft and elastic material such as silicone rubber or thermoplastic elastomer.

The membrane <NUM> is positioned above a pressure chamber <NUM> that is also annular and continuous at the periphery of the liquid interfacing part. A hard valve actuation ring <NUM> is further provided which is positioned adjacent the annular membrane <NUM> to act on the membrane for closing the chamber <NUM> upon a force is exerted thereon by the pivot means. For this, the valve actuation ring <NUM> has a plurality of protrusions <NUM> evenly distributed on its upper surface; each protrusion being positioned in an aperture <NUM> of an upper disc-shaped support portion <NUM> of the liquid interfacing part.

Each pivot means <NUM> is provided above the apertures <NUM> with a cam surface <NUM> that is arranged to engage the protrusion <NUM> of the actuation ring when rotated in a privileged direction (e.g. in clockwise direction). The pivot means <NUM> are mounted in a pivotable manner in the support portion <NUM>. The axis of pivot <NUM> of each pivot means is preferably perpendicular to a radius of the liquid interfacing part. As a result, the pivot means are capable of rotating in radial directions by the effect of the centrifugal forces when the liquid interfacing means is rotated.

In the illustrated example, there are six pivot means pivoting about six different hinges <NUM>. The pivot means <NUM> comprises a mass of inertia <NUM> (e.g. copper piece) at its free end opposite the cam surface. The mass of inertia amplifies the lever force created by the cam surface on the actuation ring.

The actuation ring is further linked to a plurality of spring elements <NUM>. The spring element <NUM> is arranged, such as in a recess of the liquid interfacing part, to pull the actuation ring in a direction (A) away from the closing position of the membrane in the chamber (<FIG>). For example, the spring element <NUM> acts in traction via a linkage formed by an intermediate arm <NUM> attached to a pin <NUM> of the actuation ring. There are as many spring elements and linkages as pivot means. The position of the spring elements can be angularly offset relative to the pivot means <NUM>, for providing a sufficiently compact structure. However, many other arrangements are possible.

The pressure chamber <NUM> is preferably annular and outwardly delimited by a annular restriction ridge <NUM> which is engaged by the soft elastic membrane when the pivot means are moved against it via the valve actuation ring. Therefore, the beverage flow can distribute in the pressure chamber <NUM> in the circumferential direction (B). Of course, the annular restriction ridge can be provided alternatively or additionally on the surface of the soft membrane.

It can be noted that the two preceding modes (<FIG> and <FIG>) can have many common features such as the features described in relation to <FIG>. The working curve described in relation to <FIG> also applies to the second embodiment.

In particular, at low rotational speeds (i.e., at or under a certain threshold) of the device, the valve remains open with the soft elastic membrane in disengaged position (<FIG>) and the spring element pulling the actuation ring in direction (A) away from the pressure chamber. As a result, the chamber is open and beverage can flow from the capsule and channel <NUM>, to the interfacing part and the pressure chamber <NUM> and be centrifuged in outward direction (L). In this state, the backpressure exerted in the pressure chamber is low and depends on the restriction opening <NUM> between the restriction ridge <NUM> and the soft membrane <NUM>. This restriction opening can be determined to provide more or less crema.

When the rotational speed increases, the pivot means <NUM> are pivotally moved in the radial directions by the centrifugal forces. The pivot means act via their cam surfaces on the actuation ring and press the soft membrane towards the pressure chamber. The actuation force is directed towards the soft membrane (direction C in <FIG>) and counters the traction force of the spring element (direction A in <FIG>). The centrifugal force FL coming from the centrifuged liquid in the conduit <NUM> and pressure chamber also tends to maintain the soft membrane at least partially open and adds to the force of the spring FA. A dynamic pressure equilibrium is therefore obtained in which, at a sufficient rotational speed, or speed range, the valve exerts on the beverage a backpressure (higher than at low rotational speed) and the liquid can be expelled from the pressure chamber. In this operating mode, the backpressure is such that crema is generated in the finished beverage product.

In the embodiment of <FIG>, the valve <NUM> comprises a compressible beverage conduit <NUM> which is arranged for being compressed by a compressing member <NUM>. The compressing member is arranged to move by effect of the centrifugal forces (direction Fc) which exert when the capsule is rotationally driven by the liquid interfacing part <NUM> and a capsule holder <NUM>. The compressing member is connected to a spring element <NUM> arranged for maintaining the compressing member in a non-compressing state of the conduit when sufficiently low centrifugal forces are present, i.e., at sufficiently low rotational speeds or within a low speed range. The spring element <NUM> can be fixedly connected to the rotatable part <NUM>. In the non-compressing state, the beverage conduit is maintained sufficiently open so that no or low hindrance of the beverage flow is provided. In this state, the backpressure created by the valve <NUM> is inexistent or low. As the centrifugal force increases, i.e., at higher rotational speeds or within a higher range of rotational speeds, the compressing member is forced in compression against the compressible conduit <NUM> (flow resistance increasing direction). In this second state, the conduits deforms and a restriction is created as the cross-section of the conduit diminishes thereby creating a backpressure on the beverage flow.

It should be noted that the compressible conduit in the beverage draining means may form only a portion of the whole beverage conduit. It may be a soft tube such as silicone or nitrile-rubber tube. For instance, it may extend from a beverage inlet <NUM> at the inner surface of the liquid interfacing part to a beverage outlet <NUM> positioned in front of the beverage collector <NUM>.

In the embodiment of <FIG>, the valve <NUM> comprises a compressible conduit <NUM> which embeds the biasing or force restoring means <NUM>. The biasing means can be formed by at least one portion of wall of the conduit or by the conduit itself which deforms elastically under the pressure of a compressing member. The compressing member can form a pivot means <NUM> with a pivotable arm <NUM> hinged at a hinge or rotation axis <NUM> and a compressing portion <NUM> forming the free end of the compressing member. The compressing portion may be enlarged compared to the arm so as form a centrifugal mass of inertia that imparts a significant closure force on the compressible conduit <NUM> when being submitted to centrifugal forces. The conduit may be given a non-circular cross section at the surface where it is squeezed by the compressing member.

It should be noted that the compressing member may translate rather than rotate.

The embodiment of <FIG> provides a variant in which the valve is operated by external valve operating means which control the state of the valve independently from the centrifugal forces during rotation of the capsule and capsule holder. In particular, the valve <NUM> comprises a valve or drive actuator <NUM> which controls the states of the valve when receiving a dedicated input from the control unit. For example, the valve actuator can be a solenoid which acts on a valve compressing member <NUM>. The valve compressing member <NUM> engages a resilient compressible conduit <NUM>, e.g. by pinching such conduit. In a first state (dotted lines), the valve actuator is retracted in such a manner that the conduit is uncompressed and the backpressure created by the valve is relatively low. This state preferably corresponds to low rotational speeds of the liquid interfacing part. In a second state (full lines), the valve actuator <NUM> is extended to force the compressing member <NUM>, in the flow resistance increasing direction, to pinch the conduit sufficiently to create a significant backpressure. The conduit is significantly deformed thereby hindering the flow of centrifuged beverage. This state preferably corresponds to higher rotational speeds. The transition from one state to the other can be triggered by the control unit in response to an input reflecting the rotational speed of the capsule in the device.

Claim 1:
Device (<NUM>) for preparing a beverage from a substance contained in a capsule (<NUM>),
the device (<NUM>) comprising:
- a capsule holder (<NUM>) arranged for holding such capsule,
- means (<NUM>, <NUM>) for rotationally driving the capsule at an adjustable rotational speed,
- a liquid feeding unit (<NUM>, <NUM>) for feeding liquid into the capsule, and
- beverage draining means (<NUM>) for draining a beverage produced in the capsule (<NUM>),
the beverage draining means (<NUM>) comprising at least one valve (<NUM>), at least one external valve operating means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) applying a force from outside the beverage draining means (<NUM>) being arranged to control the state of the valve (<NUM>), wherein said force is not produced by beverage flowing inside and against an inner wall or other element of the beverage draining means,
characterized in that said force from outside the beverage draining means (<NUM>) is arranged to control the state of the valve (<NUM>) in order to modify the flow resistance of the beverage draining means (<NUM>).