Device and method for producing milk-air emulsions

Abstract

A device for producing a milk-air emulsion, which has at least one steam lance (1) which has at least one outlet opening (22) and which is designed to be immersed at least with the outlet opening (22) into a vessel (2) filled with milk, wherein with the aid of a steam system (7) and with the aid of an air system (8) steam and air can be guided through the steam lance (1) and its outlet opening (22) into the milk, wherein the steam lance (1) has a device for height adjustment which is designed such that the vertical position of the steam lance, in particular the vertical position of the outlet of the steam lance, is adjustable.

Description

The invention relates to an apparatus and a method for producing a milk-air emulsion, preferably a milk froth.It is known to produce a milk / air emulsion, in particular a milk froth, in a vessel such as a pitcher which is filled with milk, with the aid of a steam lance which can have a steam line and an air line. For this purpose, a person preparing the coffee using a coffee machine generally holds the pitcher under the steam lance until this person has the temperature and consistency of the milk froth added. This is a manual method in which the steam lance is immersed in the pitcher filled with a correspondingly suitable quantity of milk and foamed with a special sequence or a special method-possibly including suitable movements-until the required temperature and consistency are reached.The invention has the object of providing, while maintaining the principle of a steam lance immersed in the milk in a vessel, an optimized device for producing a milk-air emulsion and also an optimized method for producing a milk-air emulsion with such a device.The invention achieves this object by a device having the features of claim 1 and by a method having the features of claim 17. According to claim 1, a device for producing a milk-air emulsion is provided, which comprises at least one steam plant, which has at least one outlet opening, and which is designed to dips at least with one outlet opening into a vessel which can be filled completely or partially with milk and is preferably open towards the top, wherein steam and air can be conducted through the steam plant and its outlet opening into the milk, wherein the steam lance has a device for height adjustment which is designed such that the vertical position of the steam lance, in particular the vertical position of the outlet of the steam lance, can be adjusted.The device according to the invention provides a number of advantages. Since the foaming result during foaming of "milk"-in the sense of animal milk or vegetable milk substitutes-is substantially co-determined by the immersion depth of the steam nozzle (= steam / air outlet opening(s) of the steam lance), an optimum immersion depth can be approached individually for the product by the height adjustability or the height adjustment of the steam plant independently of the vessel or pitcher (foaming cans or the like) and independently of its geometry and the amount of milk. This makes it possible to improve and automate the result of milk / air emulsion production and yet maintain the principle of milk production in a vessel into which a steam lance is exchanged. Preferably, for this purpose, it is preferably provided that the device for height adjustment is designed to move the outlet of the steam lance to different vertical positions within the vessel, in particular to a position which is selected such that the at least one outlet lies below the upper level or the level of the milk.It can optionally be provided in particular advantageously that the device for height adjustment is designed to move the outlet of the steam lance to various vertical positions inside and outside or inside the vessel. The latter is additionally advantageous in order to be able to create free space, if necessary, for example for large pitches or in order to facilitate cleaning.The vessel is preferably designed to be open in the vertical direction. Before the milk / air emulsion is produced, it is partially filled with milk up to a milk level.Conceivable here, on the one hand, is a design of the device for height adjustment as a manually actuatable mechanically designed device for height adjustment, in which a user can manually vertically move the steam lance and its outlet via an adjustment mechanism such as a spindle drive, for example. However, it appears even more advantageous--since the method for milk / air emulsion production can be automated further in this way--if the device for height adjustment according to a preferred embodiment of the invention has a drive device and an adjustment mechanism and if it is designed in such a way as to move the outlet of the steam lance to various vertical positions, in particular within the vessel. However, it is also conceivable that the steam lance can be pulled completely out of the vessel.The vessel is usually placed on a drip grid. It is usually open at the top and overall so high that it can be filled with milk that the at least one outlet can be moved below the milk level.According to a particularly preferred embodiment, the drive device comprises an electric motor. This can act, for example, on the adjusting mechanism, in particular an adjusting gear such as a spindle drive or a rack and pinion gear, in order to effect the height adjustment in a motorized manner.Optionally, it can also be provided that the vertical movement can be superimposed by a movement of the steam lance or its outlet in another direction (e.g. a horizontal movement or a rotational movement).With the aid of the motor-driven height adjustment, preferably in combination with a sensory medium detection, the optimum immersion depth can be determined independently of the geometry of the vessel (pitcher, froth cane or the like) and the milk quantity and can preferably be approached individually for the product. Furthermore, the automatic positioning of the lance for rinsing or cleaning purposes, as well as a movement to an advantageous rest position, are possible. The flexibility when using the steam lance is significantly increased, milk losses are reduced and handling is simplified for the user.According to a particularly preferred embodiment of the invention, it is provided that the device for height adjustment is coupled to a control device, with which the device for height adjustment can be controlled. In this way, the prerequisite for automated height adjustment of the outlet of the steam lance during the milk / air emulsion production is created in a simple manner.According to a further preferred embodiment, it can then be provided that a milk-air emulsion generation program can be stored and executed on the control unit, which program has access to a memory on which at least one or more milk / air emulsion generation profiles is / are stored, so that the steam and the air can be directed into the milk according to a respectively selected milk / air emulsion generation profile in order to automatically generate the milk / air emulsion in the vessel according to an optimized flow profile.In this case, it can then advantageously and expediently be provided that the milk-air emulsion generation program has a program part for controlling and / or regulating the vertical position of the outlet of the steam lance. This is advantageous since an optimum automated setting of the vertical position of the outlet of the steam lance is thus possible in each case at a particularly suitable location-for example shortly below the surface or level of the milk. Change of the optimum position by the volume increase during the foaming process.In this case, for yet a further optimization of the generation of the milk / air emulsion, it can also advantageously be provided that one or more sensor devices are provided which is / are coupled to the control unit and whose output signals are used to set the vertical height of the outlet of the steam lance.It has proven to be expedient if the one or more sensor devices comprise one or more of the following sensors: a temperature sensor and / or a milk sensor. It should be possible in particular to sense whether milk is present in the vessel and, if appropriate, up to what level. In this respect, the use of a collision sensor as a milk sensor is also conceivable.In summary, it is also possible, with the help of the sensors mentioned, to automatically produce a milk / air emulsion in a simple manner, while maintaining the "crop principle" according to a flow diagram, after filling the vessel therein. The generation is preferably ended after a limit value (e.g. a time limit value or a temperature limit value) included in the scheme is reached. According to a simplest embodiment, the at least one scheme can contain constant amounts of steam and air supply over a defined period of time. However, it can also be of more complex construction, which will be explained further below with reference to examples.Above and below, the terms "milk-air mixture" and "milk-air emulsion" and "milk froth" are used as synonyms. The term milk is not to be understood as being too narrow. It comprises in particular animal milk as well as wholly or partly vegetable milk products (e.g. oat milk and soy milk).It is expedient if the air system has at least the following: at least one or more air throttles, at least one controllable air pump connected to the control unit and an air line. Then, according to a variant, it can be provided in particular further expediently and advantageously that the at least one air throttle is connected to the control unit and that it is designed as an actuatable motor-driven air throttle. According to a further advantageous variant, it can also be provided alternatively or optionally that the delivery rate of the air pump can be automatically changed and adjusted by the control unit. This type of control is simple and reliable. And according to another variant, it can be provided advantageously and in a structurally simple manner that the plurality of air throttles are designed as static air throttles, to which one or more air selector valves connected to the control unit and controllable by the latter are assigned. On the device-in particular on a coffee machine with the device-there are preferably formed a display for outputting information during the program sequence and an input unit-for example in the manner of a touch display-for inputting data, for example for preselection and presetting of the type of milk and the like.It can further advantageously be provided that the steam system has at least one steam boiler, at least one controllable steam valve and a steam line.It is also possible that the air line and the steam line open into a common combined steam / air line which is guided through the steam lance, which can be immersed in the container of the milk.However, it is also conceivable that the air line and the steam line are guided separately through the steam lance, which can be immersed in the container for the milk, or that the air line and the steam line are guided separately through the steam lance and an air lance, which can each be immersed with their respective outlet into the container for the milk. The steam lance and the air lance can then also be adjustable. The term "steam lance" in this case comprises both the actual steam lance and the air lance.It is also advantageous according to an advantageous development if the memory is a local memory or a cloud memory. The "connections" within the scope of this document can be designed to be wireless or wired if they are designed or can be designed as data connections.The flow chart may also be changed or completely re-generated, for example manually or adaptively, e.g. in response to one or more measurement results.The invention then also provides a beverage machine, in particular a coffee machine, having at least one device according to one of the claims related thereto.It is then conceivable and advantageous if the milk / air emulsion production profile is adapted to one or more operating parameters during the production of the milk froth. For this purpose, at least one or more operating parameters can be / are determined once or several times during the sequence, which is / are used for adapting the milk / air emulsion production profile.A wide variety of control or sequence profiles can be generated and used. According to an advantageous milk / air emulsion production profile, the control of the air system comprises a plurality of phases, wherein in a first phase there is initially no addition of air up to a temperature value "1", then in a second phase there is a small addition of air up to a temperature value "2" and then in a third phase there is a large addition of air up to a temperature value "3" and then in a fourth phase there is a very small addition of air above a temperature value "4".Within the scope of the present invention, the method according to the invention and / or the device according to the invention can be used in an apparatus for dispensing, and in particular also for preparing, a beverage. A corresponding device is preferably designed as a fully automatic coffee maker.Further advantageous embodiments are mentioned in the other dependent claims.The invention is described in more detail below with reference to the drawing on the basis of exemplary embodiments. It should be emphasized that these exemplary embodiments are not to be understood as restrictive. The invention is implemented particularly advantageously in this exemplary embodiment. The individual features of these exemplary embodiments can advantageously be used in combination with the respective further features of the exemplary embodiments. However, they can also be combined with other exemplary embodiments shown or not shown and are also each suitable as advantageous embodiments of the subject matter described in individual or multiple of the main and dependent claims. It shows: FIG. 1 shows a schematic illustration of the structure of a first apparatus according to the invention for producing milk-air emulsions, in particular milk froth; FIG. 2 shows two different states of a section of an apparatus according to the invention for producing a milk-air emulsion; FIG. 3 is a flow chart illustrating an exemplary method for preparing a milk-air emulsion.In the following description of the figures, various exemplary embodiments are described.FIG. 1 shows a first exemplary structure of an apparatus according to the invention for the automated production of milk-air emulsions. The device can form an integral part of a beverage machine, in particular a coffee machine. This coffee machine can be designed in a wide variety of ways. However, it can also form a separate unit, which is placed, for example, as an independent device next to a beverage machine. This is because the device for producing milk foam is-whether integrated into the beverage machine or formed separately-substantially separate from a section of the coffee machine with which the coffee is produced.The devices of FIG. 1 for producing milk-air emulsions serve to produce a milk-air emulsion, in particular in the manner of a milk foam, from a medium such as milk 3, which is preferably "untreated" or filled from the packing or a tank into a vessel 2, by means of at least one steam lance 1, which dips into the vessel 2, with the aid of air and steam, which are conducted into the milk through the steam lance 1, with the aid of an automated control of the addition of air and steam into the milk. The term "milk" is not to be understood as being too narrow. It comprises, on the one hand, animal milk varieties but also non-animal vegetable milk substitutes such as soybean milk or oat milk or the like.This milk froth can then be used to prepare a coffee specialty. Thus, for the preparation of a cappuccino or the like, the milk foam can be filled, for example, into a cup which has previously been partially filled with coffee or which is subsequently to be filled with coffee.The steam lance 1 can have an elongated shape which enables it to be immersed from above in a vessel 2, such as a cup or a pitcher. It can have an outer jacket in the manner of a tube. This outer jacket may be formed of metal or another material such as ceramic. A combined steam / air line 4 is guided through the steam lance 1. This has an outlet at its end, which can be designed as a steam nozzle 22.In or on the steam lance 1, a temperature sensor 5, for example a thermometer, can furthermore be formed. This can be connected, or a data link such as a line 21, or wirelessly to a control device 9 (which can be designed as a CPU). It is arranged in such a way that it normally dips with the free end of the steam lance 1 into the medium such as milk located in the vessel 2.Furthermore, a milk sensor 24, for example a conductivity sensor, can be arranged in or on the steam lance 1. This too can be connected to the control device 9 (which can be designed as a CPU) via a data link such as a line or wirelessly. The milk sensor 24 is also arranged in such a way that it can normally be immersed with the free end of the steam lance 1 into the medium such as milk located in the vessel 2. For this purpose, it must be capable of being immersed vertically (direction V) up to or below the milk level or the upper milk level in the vessel 2.The milk can be introduced-for example in the embodiment of FIG. 1-from a separate container or-and this is particularly preferred-from a tank and an outlet of the automatic beverage machine into the vessel 2-here the pitcher.The air system 8 can be designed or constructed in various ways. Exemplary embodiments are shown in FIG. 1. However, the invention is not limited thereto. The air system 8 could also be constructed in another manner.According to FIG. 1, the air system 8 according to an advantageous embodiment has an air inlet for air from an "air source 12", which can be formed from a tank or, for example, also from the ambient air. Downstream of this air source 12 there can be arranged in the air line 14 at least one throttle 13, in particular a motorized air throttle, and an air pump 11, whereby means are provided by which the air can be conveyed from the air source 12 through the air line 14 into the steam air line 4.Preferably, the quantity of air that is conducted into the steam / air line 4 can be changed by a corresponding control by the control unit 9. For this purpose, the motorized air throttle 13 and / or the air pump 11 can be controllable and can be connected to the control unit 9 at least via a control path (a wired line or configured wirelessly).Alternatively, an actuatable air throttle 13 can also not be provided. In order that the quantity of air which is conducted into the steam / air line 4 can nevertheless be varied, a plurality of chokes can be provided.It is also conceivable that the at least one controllable air pump is designed such that its delivery capacity can be changed during operation of the air pump, for example can be adjusted with the aid of the control unit.The steam system 7 can also be designed in various ways. Its task is to generate steam from water and to conduct it-possibly via an intermediate line such as the steam / air line 4-into the steam lance 1. A particularly preferred variant is shown in FIGS. 1 and 2 a, 2 b.The steam system 7 can be connected to a water source 16, which can be formed, for example, from a water pump or another water supply.Downstream of this water source 16 there may preferably be provided a flow meter 17, a controllable fill valve 18, a steam boiler 15 and a steam line 20 with a steam shut-off and aeration valve 19. The steam line 20 can open into the steam / air line 4.The steam system 7 can, however, also be constructed in a different manner. Thus, according to an alternative embodiment not shown here, it could be provided that the vapor pressure in the vapor line can be adjusted or controlled directly or with a motor throttle in the vapor duct 20 (it can be provided that corresponding profiles for air and vapor are stored).The steam system 7 and the air system 8 can preferably each be controlled by the control device 9, on which a milk-air emulsion generation program is loaded and can be executed, wherein the control device has access to a memory, on which at least one or more milk / air emulsion generation profiles is / are stored, so that the steam and the air can be directed into the milk according to a respectively selected milk / air emulsion generation profile in order to automatically generate the milk / air emulsion in the vessel 2.A device for height adjustment is then formed on the steam lance 1, which device is designed such that the vertical position of the steam lance 1, in particular the vertical position of the outlet 22 of the steam lance 1, can be changed at least inside the vessel 2 and optionally also outside the vessel. In this case, it is provided in particular that the device for height adjustment is designed to move the outlet of the steam lance to different vertical positions within the vessel 2 (i.e. to different positions at or below the milk level at the per or the upper milk level). Optionally, it can also be provided that the steam lance is completely withdrawn from a vessel, e.g. into a resting and / or cleaning position on or in the beverage machine.It can advantageously be provided that the device for adjusting the height of the steam lance 1 has a drive device for this purpose. This can be designed in various ways. It is preferred that the drive device has an electric motor 23.It can then further be provided that the device for height adjustment is likewise coupled to the control unit 9, with which the device for height adjustment can be controlled.It can also be advantageously provided that the steam lance has one or more sensor devices, which are arranged, for example, close to the outlet 22. These sensor devices can comprise the temperature sensor 5 already mentioned, a milk sensor 24 (for "medium detection") and / or a milk level detection sensor 25. The milk sensor 24 can be designed, for example, as a conductivity sensor.The one, several or all of these sensor device(s) can be connected to the control device via a data transmission connection 21. This data transmission connection 21 can be, for example, a line designed electrically or optically for data transmission or else a radio link or the like.Air can be fed into the steam / air line 4 with the air system 8 through an air line 14 and steam can be fed together with the steam system 7 through a steam line 20 or individually through the steam / air line 4 into and through the steam lance 1 into the vessel 2.The air and the steam can be fed into the steam / air line 4 in a controlled or regulated manner. According to a first embodiment, the addition of air and steam can take place constantly according to a prestored time-dependent flow diagram. Alternatively, the flow chart may be changed or completely re-generated, for example manually or adaptively in response to one or more measurement results. This is explained in more detail below with reference to examples.In this case, the air and the steam can be conducted, for example, individually in a time-staggered manner or also simultaneously into the steam / air line 4. For this purpose, the steam system 7 and the air system 8 are each connected to the control unit 9 (CPU). This can have a CPU and a memory or be connected to it-locally or via a network or cloud connection, for example-and can be provided with a control and / or regulating program with which the steam / air supply through the steam / air supply line 4 into the vessel 2 can be controlled or regulated.It is possible here to carry out a sequence control of the method for automatically generating a milk / air emulsion using the control and / or regulating program. In this case, the sequence control preferably also comprises one or more instructions for adjusting the vertical position of the outlet 22 of the steam lance, which is adjusted in accordance with the milk level during the milk / air emulsion production.This is described in more detail below with reference to examples.The device 1 can be used, for example, advantageously as follows for producing a milk / air emulsion.The medium 3 to be heated and / or frothed, preferably milk or a milk substitute product, is introduced manually or automatically into the vessel 2-e.g. the pitcher-and positioned under the steam lance 1, wherein the steam lance 1 and especially the nozzle with the steam outlet openings 22 are intended to be immersed within the medium.The water vapor generated in the steam system 8 in a steam boiler 15 is, when triggered, with a preset steam product, conducted through the lance into the milk 3 through lines located in the coffee machine. The control of the steam generation and the necessary valve position is the one arithmetic unit and also the position of the outlet of the steam lance are called-controlled by the control unit 9, which preferably detects the duration / process time of the milk froth generation and / or the medium temperature detection with the temperature sensor 5 in parallel and which preferably also detects the milk level.The temperature measurement is carried out here by way of example by means of a sensor / sensor 5 which has a tube which also runs through the steam lance 1 and a measurement tip which exits parallel to the steam-air mixture or parallel to the outlet 22 4 can also be located outside the steam lance. The measurement can thus advantageously be carried out directly in the medium 3.The steam and / or air addition can then be controlled in dependence on parameters, for example in dependence on preset time and / or temperature values, which can be effected via the control unit 9.The air is preferably added by means of the air pump 11 which, as required, is activated by the arithmetic unit or the control unit 9 and supplies a defined quantity of air to the steam flow according to the respectively selected flow diagram-also called control profile or milk / air emulsion generation profile. The steam-air mixture 6 is conducted through the one steam / air line 4 or a plurality of internal pipelines in the steam lance 1 to the steam outlet opening or openings in the manner of (at least) one steam nozzle 22 or a plurality of steam nozzles (23) and foams up during and after the emergence of the medium 3 in the vessel-in particular in a pitcher-2.It is possible to set individual shutdown temperatures for the addition of air and steam, which are preferably between 50° C. and 70° C.It is also possible to set individual process times for the addition of air and steam, which depend on the respective amount of milk, for example 30 seconds of steam addition, starting 20 seconds of air addition in parallel for 180 ml of milk.In addition, the vertical position of the milk surface can be measured by the milk sensor 24. It is also conceivable to measure the depth of the milk in the vessel. It is conceivable to determine the conductivity thereof with the conductivity sensor.In this way, these parameters can also be taken into account when generating the milk / air emulsion.Thus, in particular in the case of milk / air emulsion production, the vertical position of the outlet of the milk lance can also be adjusted optimally with the device for height adjustment in each case as a function of the temperature and / or the milk quality and / or the vertical position of the milk level.Instead of a fixed / static air quantity addition, it is alternatively also possible to vary the air quantity before and during the foam preparation. By dynamically adapting the air quantity, individual requirements, varying environmental requirements and specific framework requirements can be regulated in order to achieve ideal foam results independently of these.The air addition control is preferably carried out as a function of the temperature and / or the time (and / or other measurable physical variables) and can furthermore be matched to the type of milk, the milk temperature, the target consistency, the target foam quantity and the target temperature.The milk froth thus produced can then be used or used for producing a beverage specialty.The milk temperature and the vapor pressure are measurement data internal to the machine and are included as initial conditions in the presetting by the control device in its sequence control.The following are given by way of example:Adjusting the amount of foam by adjusting the duration of air addition (pump run time).Adjusting the foam consistency by adjusting the air addition quantity (opening cross section).Adjusting the target temperature by defining the shutdown temperature for steam addition.And preferably, the milk level is detected with the milk sensor 24 and the vertical position of the outlet is adjusted to one or more different height positions during the milk / air flow generation.Such an example of milk / air emulsion production with a device of the type shown in FIG. 1 will be described in more detail below with reference to FIGS. 2 a, band 3.The starting point is a state in which no milk / air emulsion is produced with the device of FIG. 1.In this state, the steam lance 1 can have been moved into a (e.g. upper) rest position (see FIG. 2 a, distance 28 from the milk level 27).If a control command "generate milk froth" is now input at an input device of the coffee machine, it can be expedient to output a "warning" and confirmation "provide medium", that either a container 2 filled with milk is placed under the steam lance 1 or that such a container is filled therewith.Then, in an operating mode or step 1, a method of the lance for medium detection can be carried out until (e.g. with the aid of the conductivity sensor) it is detected that the steam lance 1 is immersed in the milk.Then, in an operating mode or step 2, a process of the steam lance in the starting foaming position can take place. For the actual production of milk froth, a position is preferably approached at which the outlet 22 of the steam lance conducts just below the milk level (FIG. 2 b, immersion depth 27). This is because at this point, the introduction of steam and / or air generally produces a milk foam which is very appealing in terms of visual appearance, consistency and taste.However, it is also conceivable to approach different heights during the preparation process during the milk / air emulsion production, which are optimally suitable for individual phases of the milk production, for example depending on the temperature and / or the conductivity.When this start-foaming position is reached, in an operating mode or step 3, the generation of the milk / air emulsion can take place in a time-controlled manner by supplying air and / or steam. A foaming profile is now run through according to the preset.Finally, when the preparation of the milk froth is completed, preparation may be completedThe vessel can then be removed and the milk froth used to prepare a beverage.Subsequently, for example, in an operating mode or a method step "purge", the steam lance can be cleaned, for example, by a water and / or steam blast through the lance.Moving to this "purge position" (for example a position inside a drip tray, which is achieved by extending into the drip tray) makes it possible to even better avoid hot water sprays and to even further reduce the risk of scalding.After the completion of the "purge" operating mode, the steam lance either remains in this position or it is moved into another rest position, for example in a housing of the beverage preparation machine.Thus, it is particularly preferably provided that a milk-air emulsion generation program can be stored and executed on the control device, which program has access to a memory on which at least one or more milk / air emulsion generation profiles is / are stored, so that the steam and the air can be directed into the milk according to a respectively selected milk / air emulsion generation profile in order to automatically generate the milk / air emulsion in the vessel 2, wherein the position of the outlet 22 of the steam lance 1 is preferably adjusted and / or changed in a motor-controlled manner at least once or several times during the generation of the milk / air emulsion.Alternatively, the position of the steam lance 1 or its outlet 22 can be adjusted manually.It is also advantageous that the height-adjustable steam lance also makes it possible to process very small amounts of milk, which are associated with a correspondingly low milk level around pitchers, to form a milk froth.It is also conceivable to adjust the lance even to such an extent that it can be moved to a cleaning and / or a purge position (for example in the drip grid) and / or a rest position (lance pulled for easier handling).It is also conceivable that particularly well suited positions of the outlet of the steam lance 1 can be learned and stored, so that they can be called up and approached during milk / air emulsion production. This makes sense, for example, if the same container is used again and again, which container is also filled again and again approximately equally (for example: with 1⁄4 I of water or milk)This can be further optimized by a medium recognition for optimum adjustment of the lance and / or for automatic start (automatic operation) or cleaning position in a kind of lance garage.This takes account of the fact that the foaming result during foaming of animal milk or vegetable milk substitutes is substantially co-determined by the immersion depth of the steam nozzle (steam / air outlet openings of the steam lance).By means of the motor-driven height adjustment, preferably in combination with a medium detection, it is possible to perform an adjustment independently of the pitcher (foaming cans or the like) The optimum immersion depth can be approached individually for the product, for the geometry and the quantity of milk. Furthermore, automatic positioning of the lance for rinsing or cleaning purposes, as well as an advantageous rest position, can be realized. The flexibility when using the steam lance is significantly increased, milk losses are reduced and handling for the user is simplified.List of reference characters1 Steam lance 2 Vessel (preferably pitcher) 3 Medium (preferably milk or milk substitute product) 4 Steam / air line 5 Temperature sensor 6 Steam-air mixture 7 Steam system 8 Air system 9 Computing unit 10 Steam / air mixing connector (steam jet nozzle) 11 Air pump 12 Air source 13 Air throttle 14 Air / air line 15 Steam boiler 16 Water supply / water pump 17 Flow rate meter 18 Filling valve 19 Steam shut-off and ventilation valve 20 Steam / steam line 21 Data transmission connection 22 Outlet opening 23 Motor height adjuster 24 Milk sensor 25 Milk level 26 Steam outlet opening 27 Immersion depth 28 Distance Milk level to steam outlet opening

Claims

Device for producing a milk-air emulsion, which has at least one steam plant (1), which has at least one outlet opening (22), and which is designed to be immersed at least with the outlet opening (22) into a container (2) filled with milk, it being possible for steam and air to be conducted through the steam plant (1) and its outlet opening (22) into the milk with the aid of a steam system (7) and with the aid of an air system (8), characterized in that the steam lance (1) has a device for height adjustment which is designed such that the vertical position of the steam lance, in particular the vertical position of the outlet of the steam lance, is adjustable.The apparatus of claim 1, wherein the height adjustment means is configured to move the outlet of the steam lance to various vertical positions within the vessel.Device according to claim 1, characterised in that the height adjustment device is designed to move the outlet of the steam lance to different vertical positions outside or inside the vessel.Device according to claim 2 or 3, characterised in that the device for adjusting the height of the steam lance has a drive device.Device according to claim 4, characterised in that the drive device has an electric motor.Device according to claim 4 or 5, characterised in that the device for height adjustment is coupled to a control device (9), by means of which the device for height adjustment can be controlled.Device according to one of the preceding claims, characterized in that a milk-air emulsion generation program is stored and executable on the control unit, which program has access to a memory on which at least one or more milk / air emulsion generation profiles is / are stored, such that the steam and the air can be directed into the milk according to a respectively selected milk / air emulsion generation profile in order to automatically generate the milk / air emulsion in the vessel (2).Device according to one of the preceding claims, characterized in that the milk-air emulsion generation program has a program part for controlling and / or regulating the vertical position of the outlet of the steam lance.Device according to one of the preceding claims, characterized in that one or more sensor devices are provided which is / are coupled to the control unit and whose output signals are used to set the vertical height of the outlet of the steam lance.Device according to any one of the preceding claims, characterised in that the one or more sensor devices comprise one or more of the following sensors: a. a temperature sensor (5) and / or b. a milk sensor (4).Device according to one of the preceding claims, characterized in that the at least one air throttle is connected to the control unit (9) and in that it is designed as an actuatable motor-driven air throttle (13) and / or at least one actuatable air pump is provided, which is designed in such a way that its delivery rate can be varied and / or in that a plurality of air throttles are provided, which are designed as static air throttles, to which one or more air selector valves connected to the control unit (9) and actuatable by the latter are assigned.Device according to one of the preceding claims, characterized in that the steam system has at least one steam boiler (15), at least one controllable steam valve (19) and a steam line (20).Device according to one of the preceding claims, characterized in that the air line (14) and the steam line (20) open into a common combined steam / air line (4) which is guided through the steam lance (4) which can be immersed in the milk in the vessel.Device according to one of the preceding claims, characterized in that the air line (14) and the steam line (20) are guided separately through the steam lance (4), which can be immersed in the container of the milk.Beverage machine, in particular coffee machine, having at least one device according to one of the preceding claims.A method for producing a milk-air emulsion from milk with a device according to one or more of the preceding claims, which comprises at least the following steps: a. providing the device, providing a vessel (2) and providing milk, b. filling the vessel (2) with the milk and arranging the vessel (2) such that the steam lance (1) can be dipped or dipped into the milk when it is being moved; c. introducing air and steam through the steam lance (1) into the milk located in the vessel (2), wherein the air system (8) and the steam system (7) are controlled by the control device with the milk-air emulsion generation program according to at least one prestored milk / air emulsion generation profile in order to generate the milk-air emulsion, and d. during the course of the milk-air emulsion generation program, the height of the outlet of the steam lance (1) is also adjusted at least once. e. wherein, depending on the milk / air emulsion generation profile, the vertical position of the steam lance, in particular the vertical position of the outlet of the steam lance (1) within the vessel (2), is also adjusted and / or adjusted once or several times.Method according to claim 16, characterised in that during the control at least one or more operating parameters is / are determined once or several times, which is / are used for adapting the milk / air emulsion production profile during the execution of the milk-air emulsion production program.Method according to claim 16 or 17, characterised in that the position of the outlet (22) of the steam lance is adjusted manually or by motor.Method according to claim 17, characterised in that during the milk / steam emulsion production, the position of the outlet (22) of the steam lance for the milk / air emulsion production is determined by means of a sensor for medium detection, which is then adjusted accordingly by motor.Method according to claim 17 or 19, characterised in that a cleaning position is approached after the milk / steam emulsion production and that a cleaning of the steam lance takes place.Method according to claim 20, characterised in that the cleaning of the steam lance is effected by means of a water blast.Method according to claim 21, characterised in that the steam lance is moved into a rest position after cleaning.Method according to one of the preceding method claims, characterized in that during the production of the milk / air emulsion the amount of air which is conducted into the milk is kept constant over time and / or the temperature.Method according to one of the preceding method claims, characterized in that during the production of the milk / air emulsion the amount of air which is fed into the milk is varied over time and / or the temperature.Method according to any of the preceding method claims, characterized in that during the production of the milk / air emulsion the amount of steam which is fed into the milk is kept constant or varied over time and / or temperature.Method according to one of the preceding method claims, characterized in that, after the milk-air emulsion generation program has been started, a data input is used to preselect the quantity of milk and / or the type of milk and / or the consistency of the milk-air emulsion to be produced.Method according to one of the preceding method claims, characterized in that the foam consistency is adjusted by adjusting the air addition quantity.Method according to one of the preceding method claims, characterized in that the target temperature is adjusted by defining the shutdown temperature for the steam addition.Method according to one of the preceding method claims, characterized in that the milk temperature in the vessel (2) is determined during the production of the milk / air emulsion, and in that this measured value is included in the sequence control.

Images