The invention relates to a device for preparing a beverage as claimed in the preamble of claim 1. Recently these types of devices are used more and more frequently in order to prepare, for example, portions of coffee or tea at a level of quality which always remains constant. In this case, as a rule, a brewing process takes place in the receiving chamber where a metered amount of hot water is directed through the portion packaging. Examples of these types of devices are described in EP 1 646 305, WO 2008/004116 or WO 2008/087099.
One problem with these devices is that after the brewing process, the metered amount of water does not flow away completely in the form of extract. Rather, a certain amount of residual water remains behind in the brewing chamber and drains away subsequently when the brewing chamber is opened to remove the used portion packaging. However, this is undesirable because the residual water contaminates the appliance or the next beverage prepared. Some contamination takes place, in particular, whenever different types of beverage are prepared using the same machine, such as, for example, coffee, tea, milk or chocolate beverages. If residual water remains behind in the closed chamber for a fairly long period, there is also the risk that a fermentation process will begin which results in irreversible changes in taste in the brewing chamber. Residual water can also remain behind in the brewing chamber for a fairly long time after a rinsing operation.
A further disadvantage of known devices is also that the outlet opening on the receiving chamber becomes clogged, it being possible for an internal pressure of about 20 bar to occur. At a pressure of this type, seals are pressed open and brewing water sprays into the machine or, in the extreme case, even outward through the input opening even when the machine has already been switched off.
DE 20 2005 021 159 proposes preventing possible residual water flowing out in an unwanted manner by means of a spring-loaded closure member which does not open until the brewing chamber is closed. However, this does not really solve the problem because the residual water flows out nevertheless when the chamber is closed and is held back when the chamber is open which means that it flows out during the next closing process.
WO 2009/115474 has made known a generically comparable device where the edge of the chamber parts, which can be pressed against each other, has gaps on at least one chamber part. Said gaps are arranged inside a defined sector such that when there is no capsule in the chamber, water flows out in a targeted manner. Sealing said gaps is only possible using capsules which have a deformable sealing material on their flange-like edge. It is not possible to close the chamber in a sealing manner without a capsule. Neither is it possible, however, to conduct away excessive fluid with the chamber closed and the capsule inserted, for example under overpressure, because the gaps at the edge are closed off in a pressure-tight manner in the closed state.
It is, consequently, one object of the invention to create a device of the aforementioned type where residual water remaining behind is able to be conducted out of the brewing chamber without the already prepared beverage or the device becoming contaminated. This object is achieved as claimed in the invention with a device which has the features in claim 1.
The initial effect of the drainage channel leading from the chamber inside to the chamber outside is that the residual water is not conducted away by means of the outlet which is provided for the finished beverage. Nevertheless, the drainage channel remains closed during the brewing process because it is arranged in such a manner on a wall section of a chamber part that it can be sealed by means of the portion packaging and/or by means of the other chamber part when the closed position is set up. This sealing during the brewing operation is important for this latter takes place in part under a pressure of more than 10 bar. As soon as the brewing chamber is opened or the portion packaging is removed, the remaining residual water is able to flow away by means of the drainage channel. In certain cases, it can even be sufficient when the overpressure in the brewing chamber decreases such that the sealing action generated by the portion packaging is lifted.
The drainage channel deploys its advantageous effect, however, directly after the brewing operation when the receiving chamber has been emptied and subsequently closed again. The process of ejecting, for example, one coffee capsule is not sufficient namely to remove all the residual water still situated in the lines. The drainage channel makes it possible for all the residual liquid to drain away from the time the machine is non-operational up until the next brewing operation. The drainage channel also acts, however, as a pressure relief valve when high internal pressure builds up. The drainage channel is opened namely before the seals can be pressed against the receiving chamber. Surplus water or even vapor are consequently conducted away by means of the drainage channel. This ensures that no sensitive machine parts such as, for example, electronic assemblies etc. can be damaged. Finally, the drainage channel also brings about optimum rinsing of the brewing chamber. The additional opening at the receiving chamber brings about namely a reduction in counter pressure during the rinsing process and consequently a greater flow rate of the rinse liquid per unit time. In particular, the drainage channel also ensures rapid emptying and drying of the receiving chamber after a rinsing operation.
It can be particularly advantageous when the drainage channel has on the chamber inside a mouth opening which is sealable by means of an outside wall section of a portion packaging enclosed in the chamber. The portion packaging can be a capsule, a pouch or another provided form. Obviously the outside configuration of the portion packaging and the inside configuration of the chamber in the region of the mouth opening must be matched to each other such that the desired sealing action is able to be generated.
However, as an alterative to this or supplementing it, the drainage channel can also be sealable by means of a closure body which is associated with the other chamber part. The closure body, for example, can be a valve body which engages directly in the drainage channel when the chamber is closed and blocks it. It would also be conceivable, however, for the drainage channel to be held in the open position by means of a spring-loaded valve when the chamber is open, the closing body on the other chamber part purely displacing the valve into the closed position. The closing body does not forcibly have to be arranged directly on the other chamber part. An indirect operative connection to another component would also obviously be conceivable.
In the case of the portion packaging being realized as a capsule, it is advantageous when one of the chamber parts is realized as a holder with a cavity for receiving the portion packaging and the other chamber part is realized as a closure part for closing the cavity and for the drainage channel to be arranged on the holder. The drainage channel can be positioned in an optimum manner in this way. In this case, how the two chamber parts are moved is basically not significant. Obviously, it would also be conceivable for the drainage channel to be arranged on the closure part. Depending on the realization of the portion packaging, the two chamber parts could also be realized in a completely symmetrical manner. An arrangement of several drainage channels on one or on both chamber parts would also be conceivable.
Further advantages can be achieved when the cavity has at least one drainage groove which, with reference to a longitudinal center axis, extends preferably from the bottom of the cavity toward the opening thereof. The drainage groove simplifies the conducting away of the residual water in particular also from the bottom region and over the entire length of the brewing chamber. In addition, the drainage groove has the advantageous effect that it simplifies the ejecting of the capsule because the suction action between the inside wall of the cavity and the outside wall of the capsule is reduced or eliminated. The drainage groove can extend in a linear manner over the length of the cavity. However, the form of a spiral or another configuration would also be conceivable.
In addition, the cavity, on the side of its opening, can have a support shoulder, which is inclined preferably at a right angle with respect to the longitudinal center axis, for supporting a complementary wall part of the portion packaging, wherein the drainage groove opens out into the support shoulder and the drainage channel begins in the support shoulder or in a region which adjoins directly thereto.
In this way, the portion packaging closes not only the drainage channel in the closed. position, but also at the same time the end of the drainage groove on the opening side. It is obviously advantageous when the drainage groove opens out into the support shoulder on the same radial plane on which the mouth opening of the drainage channel also lies.
To achieve a flow through the portion packaging, at least one chamber part can have at least one penetration element for penetrating the portion packaging in the closed position. Both chamber parts are preferably provided with at least one penetration element each, both sides of the portion packaging having to be penetrated in the closed position, however not forcibly. In the case of certain systems, penetration is effected on the outlet side first by means of deforming the portion packaging or by exceeding a tearing stress when building up an internal pressure. However, portion packagings are also known which are themselves provided with penetration means which are activated when a pressure is built up. Complicated portion packagings with in-built valves, which are opened by closing the brewing chamber or by means of the effect of pressure, are also known.
The drainage channel can have a cross section which is smaller than the cross section of the inlet opening and/or of the outlet opening. The cross section of the drainage channel is preferably between 0.1 mm2 and 10 mm2. The advantage of the relatively small cross section of the drainage channel compared to the inlet opening or the outlet opening is that it is possible to rinse the brewing chamber, the greater part of the rinse water flowing through the outlet opening and only a smaller part through the drainage channel.
In order to prevent the liquid drained away via the drainage channel contaminating the device, it is advantageous when the drainage channel leads to a vessel for receiving the drained liquid. In this case, for example, this can be the drip pan which is arranged anyway underneath the outlet for the beverage. The drainage channel could be connected to a pipe line or to a hose line for this purpose.
Finally it is advantageous when the receiving chamber is realized in a rotationally symmetrical manner and when the drainage channel is realized as a radial bore in one of the chamber parts. In the case of capsule systems usual today, the longitudinal center axis of the brewing chamber, as a rule, always extends approximately horizontally because the capsules reach their intermediate position under the effect of gravity before they are enclosed in the brewing chamber. A radial bore as the drainage channel is the shortest possible connection between the inside and the outside of the chamber. In this case, the radial bore can be arranged at the lowest point of the brewing chamber such that the residual water flows away downward. Obviously, the drainage channel does not have to extend in a radial manner with respect to the longitudinal center axis of the chamber. Depending on the design of the device, it could also extend over certain sections in an almost parallel manner with respect to said longitudinal center axis. The cross section of the drainage channel does not forcibly have to be circular either. The important thing in each case is that the drainage channel is designed such that liquid is able to flow downward under the effect of gravity. In certain cases, however, the drainage channel could also extend between the chamber inside and the chamber outside onto an elevated plane. This could be the case, for example, when a vaporous medium such as, for example, water vapor is to be conducted out of the chamber.
The conducting away of liquid via the drainage channel can be improved further when a drip skirt is arranged in the region of the outlet opening of the drainage channel on the chamber outside in such a manner that outflowing liquid can be conducted away along the drip skirt. The drip skirt preferably extends in a vertical plane and it can further be provided with a groove which leads to the outlet opening in order to promote the dripping of liquid. The drip skirt also forms protection for the opposite chamber part because it prevents liquid getting into the sealing zone between the two chamber parts and contaminating them.
The invention also relates to a capsule with the features of claim 12, said capsule being able to be inserted in a particularly advantageous manner in the above-described device. The circumferential shoulder with the wall section which is inclined or curved in cross section enables the capsule to be supported in an advantageous manner in the brewing chamber, the outside of the shoulder forming a sealing surface which can be pressed in a sealing manner against a complementary contact surface. In order to be able to achieve an optimum sealing action, the width of the wall section should be at least 1 mm. The height of the shoulder is preferably at least 3.5 mm in order to obtain a sufficiently large sealing surface. The term width, in this case, refers to the projection measurement, that is to say the width when measured at a right angle to the longitudinal center axis of the chamber. However, the relatively pronounced circumferential shoulder on the capsule has even more advantages. On the one hand, as is already known per se from WO 2008/087099, it can form a stacking edge which makes it possible to stack the still empty capsule bodies one on top of the other such that they can be better singled-out in the filling system. In addition, however, the shoulder also brings about a change in the direction of flow of the brewing water pressed into the capsule under pressure. Said water tends namely to look for a channel directly along the capsule wall in order to arrive at the outlet opening along the shortest path. This process is also referred to as “channeling” and obviously results in the extraction only draining away in an incomplete manner. The circumferential shoulder, in contrast, causes the flow to be diverted in a concentric manner toward the interior of the capsule such that no troublesome through channels can be formed on the inside wall of the capsule.
In addition, it is advantageous when the inclined wall section of the capsule is inclined by 45° with respect to the longitudinal center axis tapering toward the bottom. In this way, the acting closing forces are shared out in an optimum manner on the inclined surface. In addition, the side wall of the capsule between the bottom and the shoulder can be realized tapering toward the bottom, preferably inclined by an angle of 7° with respect to the longitudinal center axis.
Further advantages can be achieved when the capsule is deep-drawn from a film of plastics material. Films of a biopolymer such as, for example, starch or of metal or of a laminate are also conceivable. In contrast to capsules which are produced using the injection molding method, deep-drawn capsules have considerably more elasticity. This improves the sealing effect of the capsule at its shoulder in a considerable manner. In this case, it is particularly advantageous to realize the bottom of the capsule so as to be resiliently deformable toward the interior of the capsule. This is achieved in an advantageous manner by the radius at the transition from the bottom to the side wall being realized thinner than the bottom itself. The transition region, in this case, could have a wall thickness of up to 0.18-mm and the bottom could have a wall thickness of between 0.1 and 0.2 mm. As a result, penetration means present in the receiving chamber initially cause the capsule bottom to bulge toward the interior and, if needs be, the capsule bottom to be lightly pierced.
Further advantages during the brewing process can be achieved when at least one of the chamber parts has compression means which are directed against the receiving chamber and by means of which the portion packaging can be acted upon in the closed position. Said compression means are preferably used in combination with the aforementioned penetration means, preferably in such a manner that they act upon the edge region of the capsule cover. This means that the cover of the capsule is stretched tightly such that the penetration means are better able to penetrate and inflowing water is distributed over the entire cover surface. The compression means, in this case, can be realized cylindrically in the manner of a bolt or also square-shaped. The end face of said compression means can be rounded or angular. In certain cases, a combination of compression means and penetration means would also be conceivable.
The compression means can also comprise at least one resilient element which has a plurality of leaf springs which extend radially outward proceeding from a center and the resilient free ends of which act upon the portion packaging in the closed position. In this case, the arrangement of the individual leaf springs is in the manner of the legs of a spider. Penetration elements and/or further compression means, for example in the form of bolts can be arranged on the chamber part between individual or all of the leaf springs. The ends of the leaf springs not only span the cover film of a capsule but they also prevent the capsule getting stuck fast on the penetration means when the chamber is opened. The force of the leaf springs is dimensioned in such a manner that a penetrated capsule is pushed off when the chamber is opened. An arrangement of this type would obviously be extremely advantageous and expedient even in the case of conventional devices without a drainage channel.
On a device as claimed in the invention it is further expedient when the side wall of the capsule used is radially expandable under the effect of pressure, the drainage channel being sealable by means of the sealing surface of the expanded side wall. The receiving chamber, in this case, can be dimensioned such that the capsule is able to expand in a radial manner by more than 1 mm during an extraction under pressure. In this way, the capsule does not have to be dimensioned in a very precise manner to achieve the sealing effect.
Further advantages and features of the invention proceed from the following description of exemplary embodiments and from the drawing, in which:
This situation is shown in
Once the capsule has been ejected, the actuating lever 43, as a rule, is closed again such that the brewing chamber is once again in the sealed closed position, the same as in the case of the brewing operation. Residual water is able to drip away via the drainage channel 12 even in this inoperative position of the coffee machine.
An inlet opening 8 is arranged on the closure part 6 and an outlet opening 9 is arranged on the holder 5. Said outlet opening leads directly to the outlet 44. The brewing water 4 in the tank 45 is supplied to the inlet opening 8 via a pump 50 and a flow heater 49. When the brewing module is closed by activating the lever 43, a capsule that was inserted beforehand is penetrated by way of penetration means (not shown here) such that the brewing water is able to flow through the capsule. A drainage channel 12, the function of which will be described in more detail below, is arranged on the bottom edge of the holder 5.
Details of the holder are shown in
Under the effect of the internal pressure, the bottom 22 of the capsule bulges outward such that it is also penetrated by the penetration elements 19 at the bottom of the cavity. It would also be conceivable for the bottom and the cover of the capsule to be penetrated at the same time when the chamber is closed.
Under the effect of the internal pressure the circumferential sealing surface 26 of the capsule is also pressed against the mouth of the drainage channel 12 such that said drainage channel is closed in a sealing manner. It is nevertheless ensured that if excessive internal pressure is built up in the chamber 7, the liquid can create a path to the outside of the chamber via the drainage groove 15 and the drainage channel 12. The drainage channel 12 consequently also fulfills the function of a pressure relief valve. Once the brewing process has been completed, that is to say once the pressure in the chamber 7 has been reduced, surplus liquid can immediately be drained away again via the drainage channel 12, even before the brewing chamber is opened again. This prevents surplus liquid being able to be reduced exclusively via the outlet opening 9.
It would obviously also be conceivable for just the drainage channel 12, but not the mouth of the drainage groove 15, to be closed during the brewing process. Under certain conditions, however, even just the mouth of the drainage groove could be closed which, in practice, then takes on the function of a drainage channel itself.
Further cross sectional configurations of the shoulder 17 are obviously conceivable. Said shoulder could also extend in a curved manner, in particular in an arcuate manner. The important factors in each case in all the configurations are a sufficient width and a sufficient height so that a sufficient sealing surface remains present around the mouth 13 of the drainage channel.
According to
According to
As can be seen from
Obviously, different configurations of the brewing chamber and/or of the capsule or of the portion packaging are conceivable overall without departing from the object of the invention. Thus, for example, several drainage channels could be arranged at different points of the chamber parts. The same also applies to the described drainage groove, wherein it could also be possible to arrange said drainage groove on the capsule.
The bottom 22 of the capsule can have a wall thickness w of, for example, between 0.1 and 0.2 mm, whilst the wall thickness in the rounded transition region u can be just between 0.1 and 0.18 mm. The transition region acts in the same way as a bending joint which facilitates the bottom deforming inward in a flexible manner.
The basic principle of the design of the capsule holder 5 according to
Finally,
Number | Date | Country | Kind |
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09179979.1 | Dec 2009 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2010/069874 | 12/16/2010 | WO | 00 | 6/15/2012 |