Method for operating a beverage preparation device, in particular a fully automatic coffee machine with a membrane foam module

Abstract

Method for operating a beverage preparation device (01), in particular a fully automatic coffee machine, with a foam module (20), comprising a rinsing and / or cleaning operation, wherein the rinsing and / or cleaning operation is characterized by the following process steps: - Flowing a rinsing or cleaning fluid through a preferably porous membrane (10) of the foam module (20) from a first membrane surface to a second membrane surface of the membrane (10); - Draining the rinsing or cleaning fluid via a fluid chamber surrounding the membrane (10) of the foam module (20) to a fluid outlet of the fluid chamber.

Description

[0001] The present invention relates to a method for operating a beverage preparation device, in particular a fully automatic coffee machine, according to the preamble of claim 1.

[0002] Beverage preparation devices, in particular fully automatic coffee machines, are known from the prior art, which are capable of storing and / or producing a beverage substrate, for example coffee beans or ground coffee, for example by grinding coffee beans, in order to brew or extract a beverage from the beverage substrate and dispense it using fluids, in particular water. The known beverage preparation devices are designed to produce and dispense different beverages during operation. The different beverages can be influenced by various parameters, for example the amount of beverage substrate, the pressure of a pre-compression of the beverage substrate in a brewing chamber, the internal pressure of the brewing chamber during the brewing process, the volume of brewing fluid, the flow rate of the brewing fluid, the temperature of the brewing fluid, the particle size distribution (grinding degree) of the beverage substrate, and much more.This gives the operator or user, when operating a corresponding beverage preparation device, the opportunity to produce and dispense various beverages, possibly personalized according to operator preferences.

[0003] In known beverage preparation devices, it is also already well known to provide a foam module to supplement or refine the prepared and dispensed beverages with a foamed, preferably protein-containing fluid, in particular milk or milk substitute. In known beverage preparation devices, in particular fully automatic coffee machines, the integrated foam modules generally operate according to the principle of a Venturi nozzle or a jet pump, in which the preferably protein-containing fluid to be foamed is sucked in via a propellant medium, for example hot water or steam, foamed, and also dispensed through a fluid outlet of the beverage preparation device, preferably to be supplied to a beverage container external to the beverage preparation device.

[0004] The propellant is regularly also used as a heat transfer medium to heat the fluid to be foamed. Various designs of foam modules are already known in the prior art. For example, simple Venturi nozzles and multiple Venturi nozzles—connected both in series and in parallel—are known. The different designs are intended to influence the foam to be produced in as many different ways as possible in order to be able to provide different foams with regard to temperature, air content, consistency, creaminess, and the like, thus further expanding the range of beverages produced and dispensed with the beverage preparation device.

[0005] The foam modules known to date have certain limitations, particularly with regard to the foam temperature, foam consistency, and air content. When operating foam modules based on a Venturi nozzle, various methods are also known in the prior art for rinsing and / or cleaning the foam module after operation. This is intended to prevent the fluid to be foamed, which preferably contains protein, from forming deposits that could impair the function of the foam module and / or lead to hygienically questionable or dangerous conditions.

[0006] Due to the relatively simple design and widespread use of Venturi nozzles in generic foam modules, the rinsing or cleaning of known foam modules is relatively easy to manage.

[0007] In addition to the use of Venturi nozzles, WO 2014 / 069 994 A1, for example, teaches a system and method for producing a foamed food product. Compressed air is used to foam milk, which may have previously been mixed with a heat transfer fluid, using a porous membrane. A cleaning process is also provided. This is designed so that the milk supply and the hot water or steam supply are stopped, and compressed air is further pumped through the membrane to clean it of residues.

[0008] DE 10 2007 024 443 A1 discloses a method for frothing milk and a corresponding device. This document also teaches a membrane, referred to there as a flow divider, which is pressurized with compressed air to froth the milk in a milk chamber as the compressed air escapes from the porous membrane, thus generating milk foam. A particularly easy-to-clean material, in particular a plastic, simplifies cleaning of the device.

[0009] EP 2 036 472 A2 teaches an arrangement for producing milk foam. This arrangement also provides for drawing milk from a reservoir by means of a pump, heating it using a heating device, and then feeding it to a fluid chamber defined by a porous membrane. Compressed air also flows through the porous membrane into the fluid chamber and foams the milk. To simplify cleaning of the device, a hydrophobic and oleophobic material is disclosed as being particularly advantageous.

[0010] Accordingly, it is the object of the present invention to propose a method for operating a beverage preparation device, in particular a fully automatic coffee machine, with a foam module, in which the rinsing and / or cleaning operation can be carried out efficiently and effectively and at the same time the prerequisite is created to provide foams in a wider range with the foam module, in particular with regard to temperature, air content and consistency of the foam.

[0011] This object is achieved by a method for operating a beverage preparation device having the features of claim 1.

[0012] Advantageous embodiments of the invention are the subject of the following description, the description of the figures, the figures and the dependent claims.

[0013] Overall, all features subsequently disclosed by the method shall also be deemed to be correspondingly disclosed and claimable by the device, and vice versa.

[0014] The above-mentioned object is achieved by a method for operating a beverage preparation device, in particular a fully automatic coffee machine, with a foam module comprising a rinsing and / or cleaning operation in that the rinsing and / or cleaning operation comprises the following steps:

[0015] Flowing through a, preferably porous, membrane of the foam module with a rinsing or cleaning liquid from a first membrane surface to a second membrane surface and discharging the rinsing or cleaning liquid via a fluid chamber of the foam module surrounding the membrane to a fluid outlet of the fluid chamber and / or the foam module.

[0016] The present invention is therefore based on the one hand on the basic idea of ​​using a preferably porous membrane and arranging it in a fluid chamber in such a way that a fluid or driving fluid, for example compressed air, is conveyed from a first membrane surface of the membrane to a second membrane surface of the membrane during operation of the foam module, wherein the second membrane surface of the membrane is arranged in the fluid chamber in such a way that fluid to be foamed, particularly preferably a protein-containing fluid, for example milk, conveyed through the fluid chamber passes the second membrane surface of the membrane inside the fluid chamber and absorbs / incorporates fluid or driving fluid emerging there in the form of small fluid bubbles or gas bubbles into the fluid to be foamed and is accordingly discharged on the output side, for example at a fluid outlet of the fluid chamber, in a correspondingly foamed state.This allows for a significant increase in foam production options for the operation of the beverage preparation device, particularly with regard to the different properties or characteristics of the respective foam mentioned above. At the same time, this design of the foam module and its operation place special demands on the rinsing and / or cleaning of the foam module.

[0017] In this context, the invention has surprisingly recognized that by flushing the membrane from a first membrane surface to a second membrane surface and correspondingly draining the rinsing or cleaning liquid via the fluid chamber and its fluid outlet, the formation of deposits, contamination and / or the accumulation of fluid residues in or on the membrane can be particularly effectively prevented.

[0018] In the following description, the invention is described primarily in relation to or together with a fully automatic coffee machine as a beverage preparation device. However, this represents only a preferred and optional embodiment. A capsule coffee machine, for example, can also serve as the beverage preparation device, in which case a foam module, possibly including the membrane, can be detachable or removable. The beverage preparation device can also include other types and classes, such as portafilter coffee machines, milkshake makers, or the like. In an extreme embodiment, the foam module can also represent the essential beverage component of the beverage preparation device. In this case, the beverage preparation device could be referred to as a stand-alone milk frother.

[0019] The membrane can partially or completely serve as the boundary of a membrane body. This body can, for example, be cylindrical or have the shape of a truncated cone. In this case, the first membrane surface can form an inner surface or part of an inner surface of the membrane. Likewise, in such a configuration, the second membrane surface can form an outer surface or part of an outer surface of the membrane body.

[0020] The rinsing or cleaning fluid can be provided in fundamentally different ways. Particularly advantageous possibilities will be discussed in the following description. Fundamentally, however, the inventive concept is that the rinsing or cleaning fluid is at least temporarily or temporarily conveyed to the membrane or made available to the membrane in such a way that the rinsing or cleaning fluid is conveyed in the same direction as the driving fluid during normal operation of the foam module from the first membrane surface to the second membrane surface, even or especially when the driving fluid used in the use of the foam module and the rinsing or cleaning fluid are different fluids.The propellant fluid can advantageously be a gas or aerosol, such as air, whereas the rinsing or cleaning fluid is advantageously a liquid, preferably water, possibly with a detergent and / or surfactant component.

[0021] Thus, in the manner according to the invention, during rinsing and / or cleaning operation, another liquid rinsing or cleaning fluid is conveyed through the membrane, namely from the first membrane surface to the second membrane surface, wherein during other operation of the foam module and in particular of the membrane on the said path or fluid path, a preferably gaseous driving fluid otherwise passes through the membrane.

[0022] In a first advantageous embodiment of the method, it can be provided that the rinsing or cleaning fluid is supplied to the membrane via a fluid connection and, via the fluid connection, reaches a volume at least partially delimited by the first membrane surface. The volume can, for example, be designed as an internal volume if the membrane encloses or partially delimits such an internal volume. If the membrane has a different shape, the volume can also assume a different shape or configuration. In any case, however, the volume borders the membrane and ensures that the driving fluid is distributed over the membrane and its surface before it passes through the membrane.On the one hand, this can particularly advantageously result in the rinsing or cleaning liquid penetrating or flowing through the entire volume of the membrane during the subsequent discharge or conveyance from the first membrane surface to the second membrane surface. The supply can be realized, for example, via a multi-way valve which is capable of making a rinsing or cleaning liquid available at a fluid connection of the membrane. Preferably, a branch can be realized in the associated fluid path from the multi-way valve to the fluid connection of the membrane, which branch is fluidly connected to a fluid pump, in particular an air pump. The fluid pump, in particular an air pump, can preferably be used during operation of the foam module in order to also make the driving fluid, preferably air or compressed air, available at the fluid connection of the membrane.

[0023] In a further, particularly preferred development of the method, it can be provided that the rinsing or cleaning liquid is conveyed from the first membrane surface to the second membrane surface via a driving fluid, wherein the driving fluid, preferably in the form of compressed air or air, is provided via the fluid connection.

[0024] As already described above, in this way the structure or structural features of the beverage preparation device, which are also used for the operation of the foam module, can be used or co-used particularly advantageously for the rinsing and / or cleaning operation. This is because after the rinsing or cleaning liquid has been brought into contact with the first membrane surface or has been introduced, in particular filled, into a volume, preferably an internal volume, of the membrane, the rinsing or cleaning liquid can be conveyed, in particular pressed, through the membrane using the same driving fluid, preferably via the same fluid pump that also provides a fluid flow of the driving fluid through the membrane, in particular from the first membrane surface to the second membrane surface, during operation of the foam module.

[0025] According to a further, particularly advantageous embodiment of the method, it can be provided that the rinsing or cleaning liquid is supplied to the fluid chamber via a fluid inlet and at least a part of the rinsing or cleaning liquid is first conveyed or transported from the second membrane surface to the first membrane surface.

[0026] This embodiment of the method has the advantage that a fluid-conducting connection between the fluid inlet of the membrane and sources or reference points for providing or supplying the rinsing or cleaning fluid does not have to be provided. Since the corresponding fluid-conducting connection described above is not, or at least not absolutely necessary, for the operation of the foam module, a line or connection and, if applicable, corresponding infrastructure on the part of a multi-way valve can be eliminated. In this embodiment of the method, as described in more detail below, the rinsing or cleaning fluid is then first made available to a fluid inflow of the fluid chamber, for example via a corresponding fluid supply line or supply line, and from there flows into the fluid chamber.By advantageously transferring a portion of the rinsing or cleaning fluid from the second membrane surface and thus from the fluid chamber to the first membrane surface, the rinsing or cleaning fluid can reach or be conveyed to the inside or to the first membrane surface even without a corresponding supply line or indirectly. After this indirect introduction of rinsing or cleaning fluid to the first membrane surface or into a volume, preferably an internal volume, of the membrane, a correspondingly reversed conveyance of the rinsing or cleaning fluid can then advantageously take place - as already described above - which results in the rinsing or cleaning fluid being guided again from the first membrane surface to the second membrane surface and from there can be discharged via the fluid chamber.

[0027] The two crossings of the membrane by the rinsing or cleaning liquid in opposite directions can advantageously be effected by a fluid pump, in particular by an air pump, particularly preferably by one and the same air pump. In this case, the fluid pump, in particular the air pump, can advantageously create a negative pressure inside or on the first membrane surface to suck in or transfer the rinsing or cleaning liquid from the fluid chamber into the membrane or to the first membrane surface. Conversely, to expel the rinsing or cleaning liquid, the fluid pump can create an overpressure on the first membrane surface or inside the membrane by means of a reversed pumping action, such that the rinsing or cleaning liquid is again conveyed from the first membrane surface to the second membrane surface.

[0028] Accordingly, a further advantageous embodiment of the method provides that a negative pressure difference to the fluid chamber is produced, preferably via a fluid pump, via a fluid connection which is fluidically connected to a volume partially delimited by the first membrane surface of the membrane (10), so that the rinsing or cleaning liquid passes from the fluid chamber via the second membrane surface to the first membrane surface and from there into the volume, before a positive pressure difference is produced via the fluid connection, preferably by the same fluid pump, with respect to the fluid chamber, so that the rinsing or cleaning liquid located in the volume is conveyed from the first membrane surface to the second membrane surface.

[0029] In a further advantageous embodiment of the method, it can also be provided that a driving fluid, preferably via a switchable connection, can be introduced into the fluid chamber via a fluid supply line or supply line connected to the fluid inlet and when the supply line is supplied with driving fluid, the other fluids in the supply line are emptied and / or the supply line is vented.

[0030] For the sake of simplicity, the fluid supply line that connects a milk container to the fluid chamber during operation of the foam module is also referred to as the supply line.

[0031] In most cases, operation of the beverage preparation device with a membrane foam module results in a fluid pump for providing the driving fluid for operating the foam module. This can also be used particularly advantageously for the rinsing and / or cleaning operation of the beverage preparation device. For example, in the embodiment described above, the driving fluid, which is generally intended to traverse the membrane during operation and be absorbed or incorporated into the fluid to be foamed on a second membrane surface, can also be made available to a supply line to the fluid inlet of the fluid chamber during rinsing and / or cleaning operation, or the supply line can be pressurized with the driving fluid in order to empty and / or vent said supply line or at least a portion of the supply line downstream or downstream of a corresponding coupling point for the driving fluid.The other fluids can be formed by the fluid to be foamed, for example milk, and / or by rinsing or cleaning fluid.

[0032] This ensures that effective and reliable rinsing, cleaning and venting is possible even upstream of the foam module in the supply line of the preferably protein-containing fluid to be foamed. The beverage preparation device can particularly preferably be designed such that the line or fluid-conducting connection which enables the supply or provision of propellant fluid into the supply line or into a part of the supply line can be used during operation of the beverage preparation device and in particular during operation of the foam module to feed a heat exchange fluid, preferably hot water or steam, into the supply line. During rinsing and / or cleaning operation of the foam module, the said supply line can also initially be used to convey rinsing or cleaning liquid, for example water, into the supply line and can then be used by means of appropriate variable wiring to convey the propellant fluid into the supply line.This advantageously ensures that the fluid chamber can be supplied with rinsing or cleaning fluid and can be flushed through, whereby the supply line and also the fluid chamber can then be blown out or freed of residual fluids and / or vented, so that even after the rinsing or cleaning operation, no or only minimal amounts of residual fluids remain in the supply line and / or in the foam module.

[0033] Furthermore, it can advantageously be provided that the driving fluid can be introduced, preferably via a switchable connection, into a fluid supply line in the direction of a milk container. When the fluid supply line is supplied with driving fluid, the other fluids in the supply line are emptied and / or the supply line is vented. This can preferably take place together with a reversal of the conveying direction of the feed pump, so that the driving fluid can also blow out another or opposite part of the fluid supply line in the opposite direction, in addition to or alternatively to blowing out the fluid chamber.

[0034] Advantageously, the propellant fluid can be introduced with a rinsing or cleaning fluid before flowing through the membrane of the foam module. This ensures that, regardless of the side / direction in which the propellant fluid flows, any remaining milk or milk foam is first blown out and removed before the rinsing or cleaning fluid is introduced. This also reduces the amount and concentration of rinsing or cleaning fluid, since some of the milk foam or milk has already been drained from the relevant lines and components. This can also accelerate the rinsing or cleaning process.

[0035] Advantageously, it can be provided that the introduction of propellant fluid into the fluid supply line and / or the fluid chamber already takes place after a beverage has been dispensed, so that between a beverage dispensing and the remaining rinsing or cleaning operation, as little milk or milk foam as possible remains or remains in the milk-carrying components, so that only minimal residues of milk or milk foam have to be removed by the subsequent introduction of rinsing or cleaning liquid.

[0036] In a further, particularly advantageous embodiment of the method, it can be provided alternatively or additionally that, after a rinsing or cleaning fluid flows through the membrane of the foam module, a driving fluid is conveyed via a fluid connection of the membrane from the first membrane surface to the second membrane surface, thereby emptying other fluids within the membrane and / or in the volume or internal volume of the membrane. As with the fluid chamber, this can particularly advantageously ensure that no residual fluids, neither the fluid to be foamed nor the rinsing or cleaning fluid, remain on the first membrane surface or in the volume, in particular the internal volume, of the membrane.The conveyance of the driving fluid through the membrane during rinsing and / or cleaning of the beverage preparation device can be achieved particularly effectively and easily if the driving fluid is the same driving fluid that is also used during operation of the foam module and is provided via the same parts of the device, for example, an air pump. Particularly advantageously, for example, the driving fluid can flow through the fluid connection into the membrane or onto the first membrane surface for a correspondingly long time, so that the rinsing or cleaning fluid is first discharged via it, followed by venting and the removal of residual fluids or other fluids.

[0037] In a further, particularly preferred embodiment of the method, it can further be provided that the rinsing or cleaning liquid is circulated from a fluid outlet of the fluid chamber, preferably via a detachable coupling line, via a connection for a milk container and the supply line to the fluid inlet of the fluid chamber. This has the advantage that, with minimal use of rinsing or cleaning liquid, multiple rinsing of the fluid chamber and, if applicable, the second membrane surface can be achieved. To this end, it is merely necessary, in preparation for the rinsing or cleaning operation, to remove the milk container from a designated connection and attach a coupling line between the fluid outlet of the fluid chamber and the connection for the milk container.The circulation of the rinsing or cleaning liquid can preferably be realized via the fluid pump, in particular the milk pump, which, in the case of a milk container docked to the connection for the milk container, also causes or would cause the pumping of the milk or other fluid to be frothed, in particular a fluid containing protein.

[0038] In a further, particularly preferred embodiment of the method, it can be provided that the rinsing or cleaning liquid is pumped by a feed pump, preferably a roller pump, successively into the supply line to the fluid inlet of the fluid chamber and from there into the fluid chamber and, in particular with a reversed conveying direction of the feed pump, into the supply line to the fluid inlet of the fluid chamber and from there to a connection for a milk container. The sequence is reversible as desired. This means that the rinsing or cleaning liquid can also first be pumped to the connection of the milk container and then, preferably by changing the pumping direction of the feed pump, through the supply line to the fluid inlet and thus into the fluid chamber and / or through the fluid chamber.

[0039] This particularly advantageously enables rinsing or cleaning of the entire supply line to the foam module, in particular to the fluid chamber, which during operation conveys the preferably protein-containing liquid to be foamed, so that complete rinsing is possible from the connection for the milk container on the one side to the inlet into the fluid chamber and beyond, even to the outlet from the fluid chamber.

[0040] According to a further advantageous embodiment of the method, it can be provided that at the start of a rinsing or cleaning operation, the supply line to the fluid chamber or to the fluid inlet of the fluid chamber is emptied by operating a feed pump connected to the supply line in such a way that fluid in the supply line is pumped towards a connection for a milk container and, if applicable, into a milk container arranged in the connection for the milk container. This has the advantage that the supply line is already largely emptied before the rinsing and / or cleaning operation begins. This facilitates the rinsing or cleaning of the supply line and therefore allows cleaning or rinsing of the supply line with a minimum amount or volume of rinsing or cleaning fluid used.

[0041] If no milk container is arranged at the connection for the milk container, it can alternatively be provided that the milk or a corresponding milk substitute still in the supply line is dispensed or drained into a collecting container, for example a drip tray of the beverage preparation device.

[0042] Advantageous embodiments of the method according to the invention are explained below with reference to purely schematic drawings showing exemplary embodiments.

[0043] Showing: Fig. 1: a basic fluid diagram of a beverage preparation device for operation with the method according to the invention; Fig. 2: an exemplary fluid diagram of a beverage preparation device for explaining a rinsing operation according to the invention; Fig. 3: an exemplary fluid diagram of a beverage preparation device for explaining a cleaning operation according to the invention.

[0044] The Fig. Figure 1 shows an exemplary, basic fluidic diagram of a beverage preparation device for implementing the method according to the invention. In a generic beverage preparation device 01, there is often the option of dispensing heated water via a hot water outlet 03, which is fluidically connected to a hot water heater 31, for example, a thermoblock, which in turn can be fluidically connected via a fresh water connection of the beverage preparation device or a fresh water tank 32 of the beverage preparation device.

[0045] Hot water can be dispensed into a beverage container 04 located beneath the dispensing module 02 via the hot water outlet 03. Via a multi-way valve 35, the water stored in the fresh water tank 32 can be dispensed or delivered, in a heated state after passing through the hot water heater 31, or in an unheated state, in addition to the hot water outlet 03, to various other lines or fluid connections of the beverage preparation device 01, depending on the respective wiring or position of the multi-way valve 35. The multi-way valve 35 can also flexibly open / close and / or connect / disconnect other fluid connections of the beverage preparation device 01, as will be described below.

[0046] The beverage preparation device 01 comprises two brewing chamber outlets 05, which are fluidly connected to the outlet 51 or outlet of a brewing unit 52, in which a beverage, for example a coffee specialty, is brewed or leached from hot or cold water and a beverage substrate, for example ground coffee beans. A corresponding beverage can also be dispensed into the beverage container 04 via the brewing chamber outlets 05.

[0047] The dispensing module 02 further comprises a milk and / or foam outlet 06. The milk and / or foam outlet 06 is connected to a milk container 08, for example, via a detachable fluid supply line 07, wherein a further auxiliary supply line 09 can open into the fluid supply line 07. The auxiliary supply line 09 can fulfill various functions and carry various fluids, as will be described in more detail below.

[0048] During operation of the beverage preparation device 01, in particular during operation of the foam module 20 for producing and dispensing a foamed fluid, in particular milk, the auxiliary supply line 09 can preferably be used to feed hot water or steam into the fluid supply line 07 in order to thereby heat the fluid conveyed from the milk container 08, in particular the conveyed milk. This function can alternatively also be ensured via a heat exchange device in operative connection with the fluid supply line 07, which may only transfer heat without mixing or adding a fluid, for example, hot water or steam.

[0049] In the beverage preparation device 01, which is operated with the method according to the invention, a membrane 10 is arranged upstream of the milk and / or foam outlet 06, which membrane 10 is arranged in a Fig. 1 is located or enclosed by a fluid chamber not shown in detail in FIG. 1. The membrane can be supplied with a fluid or driving fluid, preferably compressed air, used for foaming purposes via a fluid connection 11. For this purpose, for example, a fluid pump designed as an air pump 12 sucks in air, compresses it, and makes it available to the fluid connection 11 via a supply line 18. Starting from the fluid connection 11, the exemplary compressed air can flow through the membrane 10 from a first membrane surface to a second membrane surface, wherein the second membrane surface is arranged within or opposite the fluid chamber in such a way that the compressed air flows through a fluid conveyed into the fluid chamber, for example cold, warm, or hot milk provided via the fluid supply line 07, and corresponding fluid bubbles, in particular gas bubbles, of the driving fluid are absorbed into the fluid conveyed through the fluid chamber.A special feature of the membrane 10 is that frothing can occur even without heating the fluid or milk. However, the use of the membrane 10 can also produce foams in other ways that cannot be achieved with a Venturi nozzle.

[0050] The membrane 10 can, for example, be designed as a sintered body made of metallic material, preferably with a correspondingly defined porosity, so that when the compressed air flows through from a first membrane surface of the membrane 10 to a second membrane surface of the membrane 10, a corresponding number of small fluid streams are generated at the second membrane surface, which are then torn off or carried along by the fluid, for example the milk, in the fluid chamber and in the process absorb the fluid flowing out of the membrane, for example air, into the fluid flowing through the fluid chamber, for example milk, and thereby foam this fluid. The membrane 10 can, for example, have the shape of a truncated cone, in the interior of which the first membrane surface and / or an inner surface of the membrane 10 is formed.

[0051] Between the air pump 12 and the fluid connection 11, a crossing 14 with a line 13 which also ends at the fluid connection 11 can be provided, which line conveys, for example, cold water or warmed / heated water from the fresh water tank 32 to the fluid connection 11 and thus to the membrane 10 or to the first membrane surface of the membrane 10.

[0052] The multi-way valve 35 can also be used to ensure that air from the air pump 12 reaches the auxiliary supply line 09.

[0053] In the Fig. 2, a rinsing operation sequence according to the invention is outlined by way of example with corresponding reference to the respective components or lines used in the beverage preparation device 01. In a first method step S1, for example, it can be provided that fluid located in the fluid supply line 07, for example milk or milk substitute, is pumped back towards the milk container 08 via the feed pump 15, which is preferably designed as a peristaltic pump or roller pump, by means of a reverse-directed operation. In a further step S2, in which the milk container 08 can advantageously remain connected to the corresponding milk connection 16, water or hot water for rinsing can be introduced into the fluid supply line 07 via the auxiliary supply line 09. As a result, the fluid supply line 07 is rinsed beyond the feed pump 15 in method step S2.

[0054] In a next process step S3, water can be provided at the fluid connection 11, which then flows into a volume that is at least partially adjacent to the membrane, preferably an internal volume that is partially enclosed by the membrane or reaches the first membrane surface of the membrane 10. This can be done via the further line 13 and represents an exemplary process step S3.

[0055] In a subsequent method step S4, driving fluid is applied via the air pump 12, in particular to the further supply line 18 and thus to the fluid connection 11 and the membrane 10, so that the rinsing liquid, preferably water or hot water, then located in the volume adjacent to the membrane, preferably the internal volume, or on the first membrane surface of the membrane 10, is conveyed, in particular pressed, from the first membrane surface of the membrane 10 to the second membrane surface of the membrane 10 and exits at the second membrane surface of the membrane 10. From there, the rinsing liquid enters the fluid chamber and can reach the foam outlet 06 of the foam module 20 via an outlet of the fluid chamber and from there be transferred to a collecting container or a drip tray.

[0056] In an advantageous embodiment, the application of driving fluid, preferably compressed air, can be maintained until not only the rinsing liquid has been conveyed from the membrane 10 or from the first membrane surface of the membrane 10 to the second membrane surface of the membrane 10, but also beyond, so that following the rinsing of the membrane 10, the membrane 10 is also blown out and thus the fluid residues are emptied.

[0057] In a subsequent, advantageous method step S5, the air pump 12 is connected to the fluid supply line 07 via the auxiliary supply line 09 using the multi-way valve 35, so that any residues of the rinsing liquid and any residues of the fluid to be foamed, such as milk, are also blown out and the corresponding fluids removed. The fluids blown out with the compressed air can be guided again via the fluid chamber to the foam outlet 06, where they are discharged into a container or drip tray.

[0058] In principle, the sequence of applying compressed air to the membrane 10 or the volume, in particular the internal volume, of the membrane 10 and the fluid supply line 07 is not necessarily as described above. Conversely, the fluid supply line 07 can also be flushed and blown out first before the membrane 10 is then blown out. In principle, the flushing fluid can also have been introduced into the membrane 10 at an earlier point in time so that it rests against the first membrane surface of the membrane 10. This can, for example, achieve a brief but nevertheless effective soaking of the membrane with flushing fluid.

[0059] The Fig. 3 shows an alternative method for carrying out a cleaning operation according to the invention of the beverage preparation device 01. In this cleaning operation, it can be provided that the milk container 08 is removed and a cleaning vessel 17 is arranged at the milk connection 16, which is provided on the one hand for storing fresh cleaning liquid, wherein the supply of fresh cleaning liquid is connected to the milk connection 16 and wherein the cleaning vessel 17 also has a receiving container 19 or collecting container with which used or consumed cleaning liquid can be received.

[0060] In a first method step S1, which may possibly still take place before the milk container 08 is uncoupled and replaced by the cleaning vessel 17, residues of the fluids located in the fluid supply line 07 can be pumped back into the milk container 08 by a reverse operation of the feed pump 15 from the direction of the foam module 20 back to the milk container 08.

[0061] In a subsequent method step S2, it can then be provided that cleaning fluid, for example a surfactant-containing water solution, optionally with corresponding additives for dissolving, detaching or removing protein-containing deposits or corresponding deposits with denatured protein, is pumped via the feed pump 15 and the fluid feed line 07 to the fluid chamber and through the fluid chamber to the foam outlet 06. For example, two cycles can be provided in which the cleaning fluid is pumped from the cleaning vessel 17 to the foam outlet 06 in such a way that a gap or pause of 10 to 20 seconds is advantageously provided between the two cycles, during which the cleaning fluid then remains in the corresponding components and hose lines essentially without feed pressure.

[0062] In a subsequent process step S3.1, rinsing liquid, for example water, can be conveyed via the auxiliary supply line 09 in the direction of the foam outlet 06, so that the rinsing liquid passes the supply line beyond the feed pump 15, the fluid chamber and the milk outlet 06. In a further process step S3.2, again by a corresponding reverse-driven feed pump, rinsing liquid can also be conveyed back to or in the direction of the milk connection 16 and, if necessary, discharged into the cleaning vessel 17. By means of a corresponding valve, it can also be ensured that the rinsing liquid reaches the container for used rinsing liquid. The corresponding valve circuit is shown in the Fig. 3 is not shown.

[0063] By rinsing with rinsing liquid via the auxiliary supply line 09, residues of the cleaning liquid can be rinsed out of the fluid supply line 07 between the milk connection and the fluid chamber or the foam outlet.

[0064] In a further process step S4, the membrane 10, as with reference to Fig. 2 already described, are firstly supplied with or flooded with rinsing liquid, for example water, via the fluid connection 11, wherein this is then conveyed by driving fluid, in particular compressed air, from the first membrane surface of the membrane 10 to the second membrane surface of the membrane 10 and advantageously the membrane is then blown out by further conveying of driving fluid through the membrane.

[0065] Alternatively, it can be provided, for example, that while the cleaning fluid is being pumped through the fluid chamber, the air pump 12 builds up a negative differential pressure or a vacuum in the volume or internal volume of the membrane 10, which then leads to portions of the cleaning fluid flowing through the fluid chamber being sucked through the membrane 10, namely from the second membrane surface to the first membrane surface. In this embodiment, instead of flushing the membrane 10 with flushing fluid, the membrane 10 can be cleaned with cleaning fluid by expelling the initially sucked-in quantity of cleaning fluid, which is arranged on the first membrane surface of the membrane 10 or in the volume, preferably the internal volume, of the membrane, in reverse, likewise by means of driving fluid, and being pumped from the first membrane surface of the membrane 10 to the second membrane surface of the membrane 10.

[0066] In a further process step S5, similar to that already mentioned with reference to Fig. 2, by appropriately switching the multi-way valve 35, it can be achieved that driving fluid also reaches the fluid supply line 07 via the auxiliary supply line 09 and thus a blowing out of residual fluids from the fluid supply line 07 and the fluid chamber is achieved. List of reference symbols 01 Beverage preparation device 02 Output module 03 Hot water outlet 04 Beverage containers 05 Brewing chamber outlet, brewing unit outlet 06 Foam outlet 07 Fluid supply line 08 Milk container 09 Auxiliary supply line 10 Membran 11 Fluid connection 12 Air pump 13 Management 14 Intersection 15 Feed pump 16 Milk connection 17 Cleaning vessel 18 supply line 19 Receptacles 20 foam modules 31 hot water heaters 32 Fresh water tank 35 Multi-way valve 51 Exit 52 Outlet of a brewing unit S1 Process step S2 process step S3 Process step S3.1 Process step S3.2 Process step S4 Process step S5 Process step

Claims

[1] Method for operating a beverage preparation device (01), in particular a fully automatic coffee machine, with a foam module (20), comprising a rinsing and / or cleaning operation, wherein the rinsing and / or cleaning operation is characterized by the following method steps: - flowing through a preferably porous membrane (10) of the foam module (20) with a rinsing or cleaning liquid from a first membrane surface to a second membrane surface of the membrane (10); - Draining the rinsing or cleaning liquid via a fluid chamber of the foam module (20) surrounding the membrane (10) to a fluid outlet of the fluid chamber. [2] Method according to claim 1, characterized by that the rinsing or cleaning liquid is supplied to the membrane (10) via a fluid connection (11) and passes via the fluid connection (11) into a volume partially delimited by the first membrane surface of the membrane (10). [3] Method according to claim 2, characterized by that the rinsing or cleaning liquid is conveyed from the first membrane surface to the second membrane surface via a driving fluid, wherein the driving fluid, preferably compressed air, is provided via the fluid connection (11). [4] Method according to one of the preceding claims, characterized by that the rinsing or cleaning liquid is supplied to the fluid chamber via a fluid inlet and at least a part of the rinsing or cleaning liquid is first conveyed from the second membrane surface of the membrane (10) to the first membrane surface of the membrane (10). [5] Method according to one of the preceding claims, characterized byin that a negative pressure difference to the fluid chamber is produced, preferably via a fluid pump (12), via a fluid connection (11) which is fluidically connected to a volume partially delimited by the first membrane surface of the membrane (10), so that the rinsing or cleaning liquid passes from the fluid chamber via the second membrane surface of the membrane (10) to the first membrane surface of the membrane (10) and from there into the volume, before a positive pressure difference is produced, preferably via the same fluid pump (12), via the fluid connection (11), so that the rinsing or cleaning liquid located in the volume is conveyed from the first membrane surface to the second membrane surface of the membrane (10). [6] Method according to one of the preceding claims, characterized bythat a driving fluid, preferably via a switchable connection, can be introduced into the fluid chamber via a fluid supply line (07) and when the fluid supply line (07) is supplied with driving fluid, the other fluids in the supply line are emptied and / or the supply line is vented. [7] Method according to one of the preceding claims, characterized by that a driving fluid, preferably via a switchable connection, can be introduced into a fluid supply line (07) in the direction of a milk container and when the fluid supply line (07) is supplied with driving fluid, the other fluids in the supply line are emptied and / or the supply line is vented. [8] Method according to claim 6 or 7, characterized by that the driving fluid is introduced with a rinsing or cleaning liquid before flowing through the membrane (10) of the foam module (20). [9] Method according to one of the preceding claims, characterized bythat after flowing through the membrane (10) of the foam module (20) with a rinsing or cleaning liquid from the first membrane surface to the second membrane surface of the membrane (10), a driving fluid is conveyed via a fluid connection (11) of the membrane (10) from the first membrane surface to the second membrane surface of the membrane (10) and in the process other fluids within the membrane (10) and / or in the volume of the membrane (10) are emptied. [10] Method according to one of the preceding claims, characterized by that the rinsing or cleaning liquid is circulated from a fluid outlet of the fluid chamber, preferably via a detachable coupling line, via a milk connection (16) for a milk container (08) and the fluid supply line (07) to the fluid inlet of the fluid chamber. [11] Method according to one of the preceding claims, characterized bythat the rinsing or cleaning liquid is conveyed by a feed pump (15), preferably a roller pump, successively into the fluid supply line (07) and from there into the fluid chamber as well as into the fluid supply line (07) and from there to a milk connection (16) for a milk container (08), or vice versa. [12] Method according to one of the preceding claims, characterized by that at the start of a rinsing or cleaning operation, the fluid supply line (07) is emptied by operating a feed pump (15) connected to the fluid supply line (07) in such a way that fluid located in the fluid supply line (07) is conveyed in the direction of a milk connection (16) for a milk container (08).

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