MILK FROTHER AND HOT DRINK PREPARATION EQUIPMENT

Description

[0001] The invention relates to a milk frother and a hot beverage preparation device with such a milk frother.

[0002] Various milk frothers and hot beverage preparation devices with such milk frothers are known from DE 196 11 450 C1 and EP 3 708 039 A1.

[0003] Hot beverage preparation devices such as fully automatic coffee machines have for some time now been equipped with milk frothers, which can be used to froth milk into milk foam. The milk is typically frothed in the milk frother by mixing a mixture of air and milk with steam, which is used to convey the mixture of air and milk as a propellant to a jet pump of the milk frother. The steam also serves to heat the mixture of air and milk to a frothing temperature. The steam is usually generated by a heater in the hot beverage preparation device and fed to the jet pump of the milk frother. The consistency and quality, i.e. its nature, of the milk foam is typically permanently determined by predetermined geometric parameters of the milk frother, in particular its jet pump.

[0004] The disadvantage is that with such conventional milk frothers, the consistency and quality of the milk foam cannot be adapted to varying consumer preferences, or at least only to a very limited extent.

[0005] It is therefore an object of the present invention to show new ways for milk frothers and for hot beverage preparation devices with such a milk frother - in particular to eliminate the aforementioned disadvantage.

[0006] This object is solved by the subject matter of independent claim 1 and the subordinate claim 10. Preferred embodiments are the subject matter of the dependent claims.

[0007] The basic idea of ​​the invention is therefore to provide a milk frother for a hot beverage preparation device or a hot beverage preparation device with an adjustable adjustment device by means of which the consistency of the milk foam can be varied. This adjustment device serves in particular for manipulating the geometric parameters of a jet pump of the milk frother.

[0008] Advantageously, the quality of the milk foam – which can at least be described by its consistency and quality – can be variably adjusted to different consumer preferences.

[0009] A milk frother according to the invention for frothing milk for a hot beverage preparation device, in particular for a fully automatic coffee machine, comprises a jet pump with a propulsion nozzle. During operation of the milk frother, steam can be expanded by means of the propulsion nozzle as the propulsion medium of the jet pump in the form of a propulsion jet discharged along a jet direction. Milk in the form of animal milk—in particular cow's milk—or milk substitutes—in particular soy, oat, rice, or almond milk—can be frothed by means of the milk frother. The jet pump has a collecting nozzle that tapers along the jet direction for collecting the propulsion jet, wherein the collecting nozzle at least partially defines a mixing chamber of the milk frother.A suction connection of the jet pump opens into the mixing chamber, in particular transversely to the jet direction, so that the water vapor of the propulsion jet and a mixture of milk and air that can be sucked in by the jet pump can be mixed in the mixing chamber to produce milk foam. An air duct and a milk container for holding milk and / or a milk duct are fluidically connected to the suction connection of the jet pump. A proportional composition of the mixture of milk and air and / or a mass flow of the mixture can be adjustable by means of one or more valve devices. The milk frother further comprises an adjusting device that can be adjusted, in particular manually, mechanically, or hydromechanically, to vary the consistency of the milk foam.Such a milk frother advantageously allows for the production of milk foam of various textures, thus meeting diverse consumer demands regarding the quality and consistency of the milk foam. The adjustment device allows the geometric parameters of the jet pump or mixing chamber to be adjusted alternatively or additionally to the frothing requirements depending on the milk type and properties such as the milk's fat and / or protein content.

[0010] Conveniently, a discharge section for discharging milk foam is fluidly connected to the milk chamber, away from the propellant nozzle. The discharge section can form a foam distributor, by means of which milk foam generated in the mixing chamber can be distributed to at least one discharge opening, preferably two discharge openings, of the discharge section. The discharge section can be used to calm a flow of milk foam downstream of the jet pump and the mixing chamber before the milk foam leaves the milk frother via the discharge opening. Furthermore, with at least two discharge openings, a number of consumption containers corresponding to the number of discharge openings can be simultaneously filled with milk foam.

[0011] In a preferred embodiment of the milk frother, the nozzle spacing measured between the propellant nozzle and the collecting nozzle along the jet direction is adjustable using the adjustment device. Such an adjustment device is particularly easy to implement technically. At the same time, a milk frother designed in this way is particularly compact across the jet direction.

[0012] According to a further advantageous development of the milk frother, the mixing chamber extends along the jet direction over a chamber height that can be adjusted using the adjustment device. Such a milk frother also requires very little installation space perpendicular to the jet direction. Furthermore, such a milk frother impresses with its particularly low manufacturing costs and great robustness.

[0013] In a further preferred embodiment of the milk frother, the catching nozzle is formed, at least in part, with or from a flexible material, so that the geometry of the catching nozzle can be changed by means of the adjusting device by deforming the catching nozzle at least in part. The catching nozzle can be shaped like the bell of a trumpet or other wind instrument, the curvature of which changes during deformation. This allows for particularly precise adjustment of the consistency of the milk foam to the consumer's preferences.

[0014] A further preferred development of the milk frother provides that the adjusting device comprises a ring whose rotational symmetry axis runs parallel to the jet direction. The ring encloses the collecting nozzle, defining a constriction in the collecting nozzle. The position of the adjusting device ring relative to the collecting nozzle is adjustable along the jet direction, so that the position of the constriction in the collecting nozzle relative to the jet direction can be changed using the adjusting device. Such a milk frother is particularly compact both along the jet direction and transversely to the jet direction.

[0015] For practical purposes, the constriction can be adjusted to tighten or loosen the constriction using the adjustment device. This allows the desired consistency of the milk foam to be adjusted even more precisely.

[0016] In a further advantageous development of the milk frother, the nozzle can be adjusted to either expand or compress the nozzle along the jet direction using an adjustment device. Such a milk frother is particularly easy to implement from a technical perspective.

[0017] According to a further preferred development of the milk frother, the adjustment device allows the position of the propellant nozzle relative to the collecting nozzle to be adjusted transversely to the jet direction. This allows for particularly good adherence to the limits specified along the jet direction, which define the installation space for the milk frother along the jet direction.

[0018] The catching nozzle and / or the propelling nozzle can be adjusted relative to one another using the adjusting device. This allows the consistency of the milk foam to be varied particularly precisely.

[0019] In a further preferred embodiment of the milk frother, the adjustment device comprises an electric rotary drive and a control element with openings. The control element can be driven in rotation about a rotation axis by means of the electric rotary drive. The control element is partially arranged in a suction channel opening into the suction connection of the jet pump in such a way that the openings of the control element periodically release the suction channel with fluid upon rotation of the control element. Whenever the suction channel is not fluidically released by the openings, the suction channel can be fluidically closed by the control element. The control element is a control disc with axially recessed openings or a control cylinder with radially recessed openings.The control cylinder preferably comprises circumferential rows of apertures of different geometries, arranged axially at a distance from one another, and is axially adjustable relative to the suction channel for selective engagement with the suction channel of one of the rows. This allows the consistency of the milk foam to be varied very finely or even continuously by changing the speed of the control element.

[0020] The invention further relates to a hot beverage preparation device, in particular a fully automatic coffee machine, comprising a milk frother according to the invention as described above. The above-described advantages of the milk frother according to the invention therefore also apply to the hot beverage preparation device according to the invention.

[0021] The hot beverage preparation device expediently includes an input device for entering the consumer's preference. The desired consistency of the milk foam can be entered directly using the input device or indirectly by selecting a specific beverage type, to which a predetermined consistency of the milk foam is assigned in a control / regulation device of the hot beverage preparation device. Such a hot beverage preparation device impresses with its intuitive operation.

[0022] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0023] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified but also in other combinations or in isolation, without departing from the scope of the appended claims.

[0024] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0025] They show, schematically Fig. 1 shows an example of a structure of a hot beverage preparation device according to the invention with an example of a milk frother according to the invention, Figs. 2 and 3 each show a further example of the milk frother according to the invention, Fig. 4 shows an example of a control element for the milk frother of the Figure 3 .

[0026] In the Figure 1A schematic diagram of a hot beverage preparation device 2 according to the invention is shown, which can be a fully automatic coffee machine. The hot beverage preparation device 2 comprises a milk container 16 for holding milk. The hot beverage preparation device 2 also has a milk frother 1 according to the invention, which in the Figure 1 is also illustrated by way of example. The milk frother 1 comprises a jet pump 4 with a suction connection 7, through which milk held in a milk container 16 of the hot beverage preparation device 2 can be sucked in by means of the jet pump 4. The milk frother 1 serves to froth milk. Milk in the form of animal milk—in particular cow's milk—or milk substitutes—in particular soy, oat, rice, or almond milk—can be frothed by means of the milk frother 1.

[0027] The Figure 1shows that the jet pump 4 of the milk frother 1 has a propulsion nozzle 3. During operation of the milk frother 1, water vapor can be expanded by means of the propulsion nozzle 3 as the propulsion medium of the jet pump 4 in the form of a propulsion jet that can be discharged along a jet direction S. The jet pump 4 also has a catcher nozzle 5 that tapers along the jet direction S for catching the propulsion jet. The catcher nozzle 5 at least partially delimits a mixing chamber 6 of the milk frother 1. The suction connection 7 of the jet pump 4 opens into the mixing chamber 6 transversely to the jet direction S. In the mixing chamber 6, the water vapor of the propulsion jet and a mixture of milk and air that can be sucked in by means of the jet pump 4 can be mixed to produce the milk foam.

[0028] In the example of Figure 1A suction channel 14 is connected to the suction port 7, into which an air channel 17 and a milk channel 18 open. The milk container 16 is fluidly connected to the suction port 7 by means of the milk channel 18, for example, via the suction channel 14. The milk frother 1 has an adjustable adjustment device 8 for varying the consistency—described by quality and consistency—of the milk foam produced by the milk frother 1. The adjustment device 8 can be adjusted, for example, manually, mechanically, or hydromechanically.

[0029] The example of Figure 1Accordingly, a nozzle distance A measured between the drive nozzle 3 and the collecting nozzle 5 along the jet direction S is designed to be variable by means of the adjusting device 8. The mixing chamber 6 extends along the jet direction S over a chamber height K, which is variable alternatively or in addition to the nozzle distance A by means of the adjusting device 8. The variability of the nozzle distance A and the chamber height K are in the Figure 1 illustrated by means of a double arrow.

[0030] The Figure 2 illustrates a further example of the milk frother 1 according to the invention for the hot beverage preparation device 2 according to the invention. Figure 2Accordingly, the catching nozzle 5 comprises a flexible material at least in some areas or consists at least in some areas of the flexible material, so that by means of the adjusting device 8 a geometry of the catching nozzle 5 can be changed by at least partially deforming the catching nozzle 5. For example, the adjusting device 8 comprises a ring 9, the rotational symmetry axis R of which runs parallel to the jet direction S. The ring 9 encloses a constriction 10 of the catching nozzle 5, defining the catching nozzle 5. In this case, a position of the ring 9 of the adjusting device 8 relative to the catching nozzle 5 along the jet direction S is adjustable, so that a position of the constriction 10 in the catching nozzle 5 with respect to the jet direction S can be changed by means of the adjusting device 8. This adjustable mobility of the ring 9 is in the Figure 2illustrated by a double arrow. Alternatively or additionally, the catching nozzle 3 can be designed to be either expandable or compressible along the jet direction S to change its geometry using the adjusting device 8.

[0031] Figure 1 It can also be seen that by means of the adjusting device 8, a position of the driving nozzle 3 relative to the collecting nozzle 5 can be changed transversely to the jet direction S. In this case, the collecting nozzle 5 and - alternatively or additionally - the driving nozzle 3 can be adjustable relative to each other. This adjustment mobility of the collecting or driving nozzle 5, 3 is shown in the Figure 1 illustrated by another double arrow.

[0032] In the Figure 3Another example of the milk frother 1 according to the invention for the hot beverage preparation device 2 according to the invention is shown. According to this example, the adjusting device 1 comprises an electric rotary drive 11 and a control element 14. Such a control element 14 is shown separately in the Figure 4 , which shows that the control element 12 has openings 13. The control element 12 can be driven in rotation about a rotation axis D by means of the electric rotary drive 11. The control element 12 is partially arranged in a suction channel 14, which opens into the suction connection 7 of the jet pump 4, such that the openings 13 of the control element 12 periodically release the suction channel 14 with fluid upon rotation of the control element 12, alternating with a closure of the suction channel 14 by the control element 12. The suction channel 14 sweeps over the openings 13 upon rotation of the control element 12.

[0033] In the example of Figures 3 and 4The control element 12 is a control disc 15 with axially recessed openings 13. Alternatively, the control element 12 can be a control cylinder with radially recessed openings 13, although this is not illustrated in the figures. Such a control cylinder can have circumferential rows of openings 13 arranged axially at a distance from one another, wherein the openings in one row each have a geometry that differs from the geometry of the openings in the other row or rows. The control cylinder can be axially adjustable relative to the suction channel 14, so that each of the rows can be selectively engaged with the suction channel 14.

[0034] In the examples of Figures 3 and 4 The quality of the milk foam can be influenced by selecting the speed at which the control element 12 is driven by means of the rotary drive 11. List of reference symbols

[0035] 1Milchschäumer 2Heißgetränkezubereitungseinrichtung 3Treibdüse 4Strahlpumpe 5Fangdüse 6Mischkammer 7Sauganschluss 8Justiereinrichtung 9Ring 10Engstelle 11Rotationsantrieb 12Steuerorgan 13Durchbruch 14Saugkanal 15Steuerscheibe 16Behälter 17Luftkanal 18Milchkanal 19Austragsteil 20Austragsöffnung ANozzle distance DRotary axis KChamber height RRotary symmetry axis SStrailing direction

Claims

1. Milk frother (1) for frothing milk for a hot beverage preparation device (2), in particular for a fully automatic coffee machine having a jet pump (4) comprising a propulsion nozzle (3), wherein during operation of the milk frother (1) steam can be released by means of the propulsion nozzle (3) as a propellant of the jet pump (4) in the form of a propulsion jet which can be discharged along a jet direction (2); wherein the jet pump (4) has a collection nozzle (5), which tapers along the jet direction (S), for collecting the propulsion jet, wherein the collection nozzle (5) at least partially delimits a mixing chamber (6) of the milk frother (1); wherein a suction connection (7) of the jet pump (4), in particular transversely to the jet direction (S), opens into the mixing chamber (6), so that the steam of the propulsion jet and a mixture of milk and air which can taken in by means of the jet pump (4) can be mixed in the mixing chamber (6), in turn generating the milk froth; wherein an air duct (17) and a milk container (16) for receiving milk and / or a milk duct (18) is fluidically connected to the suction connection (7) of the jet pump (4), and wherein the milk frother (1) has an adjustment facility (8) which can be adjusted in particular manually or mechanically or hydromechanically in order to vary a consistency of the milk froth.

2. Milk frother (1) according to claim 1, characterised in that a nozzle distance (A) measured between the propulsion nozzle (3) and the collection nozzle (5) along the jet direction (S) is embodied to be changeable by means of the adjustment facility (8).

3. Milk frother (1) according to claim 1 or 2, characterised in that the mixing chamber (6) extends along the jet direction (S) above a chamber height (K) which can be changed by means of the adjustment facility (8).

4. Milk frother (1) according to one of claims 1 to 3, characterised in that the collection nozzle (5) is embodied at least in regions with or from a flexible material so that a geometry of the collection nozzle (5) can be changed by means of the adjustment facility (8) by a deformation of the collection nozzle (5) at least in regions.

5. Milk frother (1) according to claim 4, characterised in that the adjustment facility (8) comprises a ring (9), the axis of rotational symmetry (R) of which runs parallel to the jet direction (S); the ring (9) the nozzle (5) encompasses a constriction (10) of the collection nozzle (5) in a fixed manner; a position of the ring (9) of the adjustment facility (8) can be adjusted relative to the collection nozzle (5) along the jet direction (S), so that a position of the constriction (10) in the collection nozzle (5) with respect to the jet direction (S) can be changed by means of the adjustment facility (8).

6. Milk frother (1) according to claim 4 or 5, with reference to claim 3, characterised in that in order to change the geometry of the collection nozzle (5), the collection nozzle (5) is optionally embodied to be extendable or stowable along the jet direction (S) by means of the adjustment facility (8).

7. Milk frother (1) according to one of the preceding claims, characterised in that a position of the propulsion nozzle (3) transverse to the jet direction (S) and relative to the collection nozzle (5) can be changed by means of the adjustment facility (8).

8. Milk frother (1) according to claim 6, characterised in that the collection nozzle (5) and / or the propulsion nozzle (3) are moveable relative to one another by means of the adjustment facility (8).

9. Milk frother (1) according to one of the preceding claims, characterised in that the adjustment facility (8) comprises an electrical rotary drive (11) and a control organ (12) with apertures (13); by means of the electrical rotary drive (11) the control organ (12) can be rotationally driven about an axis of rotation (D); the control organ (12) is arranged partially in a suction duct (14) which opens into the suction connection (7) of the jet pump (4) so that the apertures (13) of the control organ (12) periodically fluidically unblock the suction duct (14) during rotation of the control organ (12); the control organ (12) is a control disc (15) with axially received apertures (13) or a control cylinder with radially received apertures (13), which preferably comprises rows of apertures (13) arranged axially at a distance from one another dependent on the different geometry and which can be axially moved with respect to the suction duct (14) for optional engagement with the suction duct (14) of one of the rows.

10. Hot beverage preparation facility (2), in particular fully automatic coffee machine, having milk frother (1) according to one of the preceding claims.