HK40007416A - Output device for a milk foaming apparatus - Google Patents

Description

Output device of milk foaming equipment

Technical Field

The invention relates to an output device of milk foaming equipment.

Background

Devices for preparing hot beverages, in particular automatic coffee machines, generally comprise automatic or semi-automatic means for preparing milk foam. In particular milk foam for preparing hot drinks such as cappuccino or latte macchiato, which are additionally required, can be formed and dispensed by such milk frothing devices.

In this case, it is common practice for such milk frothing apparatuses to form an emulsion of milk and air (milk froth) by taking in milk and air (if applicable) by the venturi effect and emulsifying the milk and air. For example, hot steam is introduced in a region of the milk frothing apparatus, so that a flow through the milk inlet channel is caused, and in the process a vacuum is generated, wherein milk in the reservoir is sucked in through the milk inlet channel and, if applicable, air is sucked in through the air inlet due to the vacuum.

Such a milk frothing device comprises an emulsifying chamber and an output section, wherein the output section is arranged downstream of the emulsifying chamber, seen in the flow direction of the milk to be frothed. A deceleration device is usually provided, in particular in the output section, to decelerate the fluid rotating in the emulsion chamber.

For example, DE 202006009786U 1 discloses a milk frothing device comprising a mixing chamber downstream of a steam supply pipe, wherein the mixing chamber is further connected to a milk supply pipe and an air supply pipe or to a milk and air supply pipe. When steam enters the mixing chamber, air and milk are drawn into the mixing chamber and mixed with the steam therein to form a milk-air-steam mixture (milk foam) according to the venturi principle. In order to improve the mixing of milk, air and steam and thus to enhance the frothing of the milk-air-steam mixture, an emulsion chamber can be provided downstream of the mixing chamber, said emulsion chamber having a deflector plate arranged transversely to the flow direction, so that the milk-air-steam mixture flowing from the mixing chamber to the emulsion chamber impinges on the deflector plate. The deflector plate is provided with a plurality of inlets for discharge channels, so that the milk foam can reach the target location as undamaged as possible. The inlet of the discharge channel is preferably concentrated around the actual deflection point, where the milk-air-steam mixture flowing into the emulsion chamber impinges on the deflection plate. The discharge opening of the discharge channel is inclined at an angle with respect to the cross-section of the discharge channel. In this way, the milk-air-steam mixture flowing through each discharge channel is deflected identically in all discharge channels, so that the milk bubbles are conveyed downstream of the discharge opening of said discharge channel in the form of a defined (uniform) overall jet.

However, according to the venturi principle, larger bubbles will be formed repeatedly during the frothing of the milk. Milk foam containing larger bubbles is generally considered unattractive by consumers. Furthermore, milk foam containing larger bubbles is generally not very smooth and therefore does not meet many consumers' expectations for its consistency.

In devices which actually comprise a milk frothing unit but are not equipped with a separate hot water outlet, the respective milk frothing unit is usually also used for dispensing hot water, since hot water is dispensed by the milk frothing unit. During this process, additional air may be drawn in so that a steady water jet is not formed. In addition, the water jet can be discharged very quickly from the milk frothing unit, resulting in splash splashing around the milk frothing unit.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved dispensing device for a milk frothing device, in which the milk froth is as uniform and fine as possible, which dispensing device also dispenses hot water and by means of which splashing of water around the dispensing device can be largely prevented.

This object is achieved by having an output device for a milk frothing device as claimed in claim 1.

The output device for a milk frothing device comprises an emulsion chamber and an output section having a fluid inlet for introducing a fluid containing milk, air and/or steam into the emulsion chamber, wherein the fluid is emulsified in the emulsion chamber to form an emulsion in the form of milk froth; the output portion has an output port for dispensing the emulsion from the emulsion chamber, wherein the output portion includes at least one output channel fluidly connected to the emulsion chamber and the output port such that the emulsion is able to flow from the emulsion chamber to the output port through the at least one output channel. In addition, a deflection surface and/or at least one deflection member is provided in the output section for decelerating and rotating the fluid introduced into the emulsion chamber.

According to the invention, a screen element arrangement with at least one screen element is provided, wherein the screen element comprises a plurality of channels and is arranged upstream of the outlet opening such that emulsion flowing from the emulsion chamber to the outlet opening has to pass the at least one screen element via at least one channel, and wherein the channels have a hydraulic diameter of 0.1-1.5mm and a length of 0.1-1.5 mm. Furthermore, the channels of the at least one screen element are arranged in a space extending annularly around the deflection surface and/or the at least one deflection member.

The definition of the term "hydraulic diameter" is provided below.

In this context, "emulsion in the form of milk foam" refers to an emulsion of milk and air, i.e. a spatially distributed mixture of milk droplets and air bubbles. The emulsion chamber of the output device is therefore suitable for receiving a fluid containing milk, air and/or steam (for example a milk-air-steam mixture or a milk-air-steam mixture), wherein an emulsion of milk and air (milk foam) is finally formed by mixing or rotating the components of the fluid in the emulsion chamber.

Since the deflection surface and/or the at least one deflection member is/are arranged in said output section and the channels of said at least one screen element are arranged in a space extending annularly around said deflection surface and/or the at least one deflection member, the fluid entering through the fluid inlet is typically decelerated on the deflection surface and/or the deflection member and rotated in the emulsion chamber before said introduced fluid passes the screen element via at least one of said channels and reaches the output opening.

For example, if milk, air and/or steam is contained in the introduced fluid, the deceleration and rotation caused by the deflection surface and/or the deflection member promotes mixing of the milk with the air and/or steam, thereby forming an emulsion having a spatially distributed mixture of emulsion droplets and air bubbles.

The deceleration of the fluid introduced in the emulsifying chamber also has the following effect: the fluid passes through the passages of the screen element and the outlet openings at a lower flow rate. Such a deceleration of the incoming fluid is also advantageous when the delivery device is used for dispensing hot water, i.e. when the hot water forms a fluid into the emulsion chamber. If hot water is introduced into the emulsifying chamber, the rotation and deceleration of the introduced hot water on the deflecting surface and/or the deflecting member are prerequisites to ensure that the hot water reaches the outlet opening at a slower speed, so that the formation of water splashes around the outlet opening is largely prevented.

Since the passages of the at least one screen element are arranged in a space extending annularly around the deflection surface and/or the at least one deflection member, the deflection surface or the deflection member distributes the fluid introduced into the emulsion chamber substantially uniformly in all areas of the screen element around the deflection surface and/or the at least one deflection member, in particular all passages surrounding the deflection surface and/or the at least one deflection member.

The screen element arrangement has the following effects: the emulsion of milk and air located in the emulsion chamber can only pass through the at least one sieve element of the sieve element arrangement via one or more channels of the at least one sieve element to the outlet opening of the outlet portion. In other words, the emulsion must also flow through one or more channels of at least one screen element.

The at least one screen element has in particular the effect that: the flow profile of the screen element with respect to the emulsion (i.e. the spatial distribution with respect to the flow velocity) influences the emulsion flowing through the at least one outlet channel. Since the emulsion passes through the screen element via the channel, the emulsion cannot pass through the screen element at a spatially constant flow rate. Due to the arrangement of the channels in the at least one screen element, the emulsion flows through the screen element at a spatially varying flow rate (depending on the arrangement of the channels). The spatial variation of the flow rate is usually achieved in such a way that the flow rate has a velocity gradient. Due to the arrangement of the channels in the at least one screen element, the spatial variation of the flow velocity is typically achieved in such a way that: the flow velocity has a velocity gradient which also varies with position, in particular in the vicinity of the channel or the respective channel upstream and/or downstream of the at least one screen element.

When the emulsion of milk and air flows through the at least one sieve element, the emulsion droplets and the air bubbles contained therein are deformed due to the velocity gradient of the flow velocity mentioned above. In this case, the respective emulsion droplet and the air bubble can be significantly deformed (depending on the respective velocity gradient) such that the individual emulsion droplet is divided into two or more emulsion droplets, each of which has a smaller volume than the individual emulsion droplet before being divided into a plurality of emulsion droplets; the individual bubble is accordingly divided into two or more bubbles, the volumes of which are respectively smaller than the volume of the individual bubble before being divided into a plurality of bubbles.

Preferably, this division of the single emulsion droplet into a plurality of smaller emulsion droplets and of the single bubble into a plurality of smaller bubbles occurs in respective regions of the emulsion in which the velocity gradient of the flow velocity is substantially parallel in direction to the flow velocity. There is usually a "elongational flow" in the emulsion zone, wherein the flow rate of the emulsion is achieved in such a way that: the velocity gradient of the flow velocity is substantially parallel in direction to the flow velocity. This elongational flow causes the emulsion droplets and the air bubbles to be significantly elongated in the direction of the flow velocity (due to the velocity gradient of the flow velocity), so that they can be separated into smaller emulsion droplets and smaller air bubbles in a particularly efficient manner. In particular, such elongational flows occur in each channel of the at least one screen element through which the emulsion flows, wherein these elongational flows are typically particularly pronounced along the central longitudinal axis of the channel. Thus, the emulsion droplets and the bubbles flowing substantially through the "center" of the channel (referring to the cross-section of the respective channel) are significantly stretched in the flow direction and, if possible, are divided into a plurality of small emulsion droplets and bubbles.

The extent to which emulsion droplets and bubbles can be separated into smaller emulsion droplets and smaller bubbles, respectively, when flowing through the channels of the at least one screen element depends on the spatial dimensions of the individual channels. It is proposed to realize the passage of the at least one screen element in such a way that: the channels have a hydraulic diameter of 0.1-1.5mm and a length of 0.1-1.5 mm.

In this way, the screen element has the advantageous effect of: the emulsion of milk and air formed in the emulsion chamber and passing through the sieve element can be dispensed from the outlet opening of the outlet device in the form of milk foam, wherein the milk foam contains a very uniformly distributed mixture of particularly small milk droplets and air, so that the formed milk foam has a uniform and extremely fine air hole and is free of any large air bubbles, so that the milk foam is considered to be very fine and visually appealing to the consumer.

The output device is also advantageous when hot water is dispensed through the emulsion chamber and the output port. In this case, the screen element has the effect of: in addition to the deceleration in the emulsion chamber caused by the deflection surface and/or the deflection member, the water flowing from the emulsion chamber to the outlet opening through the at least one outlet channel is decelerated and evenly distributed in the outlet channel. Thereby forming a compact water jet at the outlet and preventing water splash from forming around the outlet.

In one embodiment of the output device, the deflection surface and/or the at least one deflection member is/are arranged in a central region of the output opening. This central arrangement of the deflection surface and/or the at least one deflection member makes a particularly uniform distribution of the fluid into the emulsification chamber through the channels formed in the at least one screen element.

In this way, the screen element has the advantageous effect of: the emulsion of milk and air formed in the emulsion chamber and passing through the sieve element can be dispensed from the output opening of the output device in the form of milk bubbles, wherein the milk bubbles contain a very uniformly distributed mixture of milk droplets and air bubbles, thus forming milk bubbles with uniform air openings.

According to one embodiment of the output device, the at least one screen element is arranged in such a way that: which extends substantially transversely to the flow direction of the emulsion in the outlet channel. In this case, the emulsion is distributed in a particularly uniform manner in a plurality of channels, wherein the emulsion passes through the screen elements in such a way that: the emulsion flows substantially uniformly through the outlet channel (referring to the cross-section of the outlet channel).

Furthermore, the at least one screen element may be arranged upstream of and at a distance from the outlet opening. In this case, the emulsion flowing from the emulsion chamber to the outlet opening still flows a certain distance downstream of the screen element on the outlet channel before it reaches the outlet opening. In this way, the emulsion flowing to the outlet opening still flows a certain distance in the outlet channel after passing through the screen element. The effect is as follows: the emulsion is delivered in a relatively stable manner in a predetermined direction in the form of a jet through the outlet opening, so that lateral fluctuations of the jet are largely prevented.

The at least one screen element may be arranged in the emulsion chamber, for example at a distal end of the at least one outlet channel with respect to the outlet opening, or in the at least one outlet channel.

The properties of the emulsion (milk foam) dispensed from the outlet opening can be advantageously influenced and optimized by a suitable design of the passage of the at least one sieve element. In particular, the number of channels, the arrangement of the channels, and the geometric dimensions of the channels may be appropriately selected.

For example, the channels of the at least one screen element may be realized in such a way with respect to the cross-section of the respective channel: the hydraulic diameter of the channels is preferably 0.1 to 1.0mm, particularly preferably 0.3 to 0.9 mm. Furthermore, the channels of the at least one screen element may be realized in such a way with respect to the length of the respective channel: the length of the channels is preferably 0.15 to 1.0mm, particularly preferably 0.15 to 0.9 mm. This choice of the dimensions of the channels is advantageous to ensure that an acceptable amount of emulsion can flow through an acceptable amount of emulsion per time unit through the respective channel on the one hand and that the emulsion droplets and air bubbles contained therein can be effectively separated into smaller emulsion droplets and air bubbles (due to the extensional flow formed in the respective channel) when they pass through one of the channels on the other hand.

For example, the passage of the at least one screen element may be realized in such a way that: the ratio of the hydraulic diameter of the channel to the length of the channel is greater than 1:1.5, preferably greater than 1:1.25 and less than 4: 1; particularly preferably greater than 1:1.25 and less than 3: 1. In this way, the emulsion flows through the individual channels, creating an elongational flow in a relatively large area of these channels, wherein said elongational flow is particularly suitable for efficiently separating the emulsion droplets and air bubbles contained in the emulsion into smaller emulsion droplets and air bubbles when the emulsion passes through one of the channels.

Furthermore, the at least one screen element may be realized in such a way that: the number of channels is at least 10, preferably 20 to 300, particularly preferably 25 to 200, and even more preferably 30 to 160. Since the screen element comprises a relatively large number of channels, the channels can be arranged in a substantially evenly distributed manner (referring to the surface of the screen element). In this way, the emulsion will become very homogeneous after passing through the at least one screen element (referring to the cross-section of the at least one outlet channel), in particular in terms of the size and spatial distribution of the emulsion droplets and the gas bubbles in the fluid flowing through the outlet channel.

The at least one screen element may for example be realized in the form of a plate-like body provided with through holes, wherein the through holes form respective channels. Alternatively, the screen element may be realized in the form of a screen structure, e.g. in the form of a woven or braided structure of intersecting metal wires or fibers, preferably plastic, wherein the channels are realized in a "mesh" manner, i.e. the channels are formed between the metal wires or fibers, respectively, which are interconnected in a mesh-like manner. In this case, the channel may preferably, but not necessarily, be realized in a circle or an angle (e.g. a triangle, a quadrangle or a polygon).

For example, at least one screen element of the screen element arrangement 70 may be a flat planar body extending along a plane (at least in the area where the channels are provided). The screen elements may have different shapes. For example, each screen element may be realized in a curved or arched or structure extending along the contour (or at least one region of the contour) of a cylinder, cone, truncated cone, cube, cuboid, tetrahedron or the like in at least one region provided with said channels.

Furthermore, the channels of the at least one screen element may be arranged in such a way that: two adjacent channels are spaced from each other by a distance of 0.1-1.5mm, preferably 0.1-1.0mm, more preferably 0.3-0.9 mm. In this way, the channels are arranged adjacent and in close proximity to each other. Thus, a relatively large amount of emulsion can flow per time unit through the channels and the outlet channel with a substantially uniform distribution over the cross-section of the outlet channel.

In another embodiment of the output device, the screen element arrangement comprises at least two (or more than two) screen elements. In this case, the screen elements are arranged behind one another in the flow direction of the emulsion, so that the emulsion passes through the individual screen elements of the screen element arrangement in each case successively (via the flow channels of the individual screen elements of the screen element arrangement).

In this case, when the emulsion flows through the passage of the first screen element of the screen element arrangement, i.e. the passage of the first screen element through which the emulsion initially passes, the emulsion droplets and air bubbles in the emulsion are separated into smaller emulsion droplets and air bubbles. Subsequently, the emulsion flows through the next screen element after the first, and these smaller emulsion droplets and air bubbles are deformed again when flowing through the channels of the next screen element and are separated into smaller emulsion droplets and air bubbles. If the emulsion flows continuously through a plurality of sieve elements, milk bubbles are formed in which very fine milk droplets and air bubbles are distributed and which have particularly small air openings.

A sieve element arrangement having at least two (or more than two) sieve elements is also advantageous when the output device is used for dispensing hot water, i.e. when the fluid entering the emulsion chamber is hot water. The arrangement of at least two (or more than two) sieve elements is a prerequisite to ensure that the hot water reaches the outlet opening at a particularly slow speed, so that the formation of water splashes around the outlet opening is prevented in a particularly effective manner.

Preferably, two respective screen elements of the screen element arrangement which are arranged behind one another in the flow direction of the emulsion are at a distance from one another in the flow direction of the emulsion. The distance may be, for example, from 0.1 to 20mm, preferably from 0.5 to 10mm, particularly preferably from 0.9 to 5 mm. In this way, an intermediate space is formed between two screen elements of the screen element arrangement which are arranged one behind the other in the flow direction of the emulsion, wherein the emulsion flowing through one of the screen elements in this space is, on the one hand, completely rotated in the intermediate space and, on the other hand, decelerated by the other of the two screen elements, so that the flow of emulsion is smoothed out in the intermediate space between the two screen elements. This promotes homogenization of the emulsion in the intermediate space between the two screen elements, so that an emulsion with a particularly uniform spatial distribution of emulsion droplets and gas bubbles is formed.

In another embodiment of the output device, a deflection surface and/or at least one deflection member is provided between the fluid inlet and the output of the emulsification chamber to decelerate and rotate the fluid introduced into the emulsification chamber. This deceleration and rotation effect contributes to the formation of an organoleptically optimal milk foam. The channel is preferably arranged in a space extending annularly around the deflection surface and/or the at least one deflection member. In this case, the deflection surface and/or the at least one deflection member may be located, for example, centrally in the output section of the output device, while the emulsion may flow through a space extending annularly around the deflection surface and/or the at least one deflection member towards the output opening past the deflection surface or the deflection member.

According to another aspect of the invention, the emulsification chamber comprises a first emulsification chamber portion, a second emulsification chamber portion and a connecting channel forming a fluid communication between the first and second emulsification chamber portions, wherein the first emulsification chamber portion is adjacent to the fluid inlet and the at least one output channel opens into the emulsification chamber in the second emulsification chamber portion area. In this case, the fluid entering the emulsification chamber through the fluid inlet initially has to flow through the first emulsification chamber portion, however in turn through the connecting channel and the second emulsification chamber portion. The cross-section of the connecting channel, seen in the direction of flow of the fluid, is smaller than the respective cross-sections of the first and second emulsifying chamber portions.

This design of the emulsion chamber has the effect that: the emulsion must flow through the first emulsion chamber portion, the connecting channel and finally the second emulsion chamber portion in that order before it reaches the outlet channel. In this case, an emulsion of milk and air can flow through the emulsion chamber in such a way that: a elongational flow is formed in the connecting channel between the first emulsion chamber portion and the second emulsion chamber portion, wherein the elongational flow has the effect of dividing the emulsion droplets in the emulsion into smaller emulsion droplets and air bubbles when flowing through the connecting channel as air bubbles. In this way, the emulsion formed in the second emulsion chamber portion of the emulsion chamber already contains relatively small emulsion droplets and air bubbles before passing through the at least one screen element of the screen element arrangement. When the emulsion subsequently flows through at least one screen element of the screen element arrangement, the emulsion droplets and air bubbles contained in the emulsion are again separated into smaller emulsion droplets and air bubbles. Thus, milk bubbles with a very fine distribution of emulsion droplets and air bubbles and particularly small air pores are formed before the emulsion initially flowing through the connecting channel into the second emulsion chamber portion of the emulsion chamber passes the at least one screen element. Smaller emulsion droplets and air bubbles can be achieved if the screen element arrangement comprises at least two (or more than two) screen elements as described above and the emulsion has to pass through all screen elements of the screen element arrangement in order to reach the output opening of the output device.

A milk frothing apparatus for frothing milk may comprise, for example, an output apparatus of the type described above and a device for introducing milk, air and/or steam into an emulsion chamber of the output apparatus.

Drawings

Preferred embodiments of the output device for a milk frothing device according to the invention and of a milk frothing apparatus equipped with an output device according to the invention will be explained in more detail below with reference to the drawings. Wherein:

fig. 1 shows a longitudinal section through a milk frothing apparatus with a first embodiment of the output device;

FIG. 2A shows a longitudinal cross-sectional view of the lower portion of the output device of FIG. 1;

FIG. 2B shows a top view of the lower portion of the output device of FIG. 2A;

FIG. 2C shows a bottom view of the lower portion of the output device of FIG. 2A;

FIG. 3 shows a longitudinal cross-sectional view of a second embodiment of the output device;

FIG. 4A shows a longitudinal cross-sectional view of the lower portion of the output device of FIG. 3;

FIG. 4B shows a top view of the lower portion of the output device of FIG. 4A;

FIG. 4C shows a bottom view of the lower portion of the output device of FIG. 4A;

FIG. 5 shows a longitudinal section of a third embodiment of the output device;

FIG. 6A shows a top view of the lower portion of the output device of FIG. 5;

FIG. 6B shows a bottom view of the lower portion of the output device of FIG. 5;

FIG. 7 shows a top view of another embodiment of a lower portion of the output device; and

fig. 8 shows a longitudinal section through a fourth embodiment of the output device.

Detailed Description

Fig. 1 shows a milk frothing device 1 equipped with an output device according to the invention. In the present embodiment, the milk frothing apparatus 1 comprises an output device 100 with an emulsion chamber 15 and a device 110 for introducing milk and air, or if applicable, milk, air and steam, into the emulsion chamber 15 of the output device 100.

Referring to fig. 1, the device 110 includes a housing 115 formed with a hollow space 120, and an inlet 130 for supplying steam into the hollow space, an inlet 140 for supplying milk into the intermediate space 120, and a device 150 for supplying air into the hollow space 120. The inlet 140 for supplying milk is provided with a connector 145 for a line (not shown) having one end connected to the connector 145 and the other end connected to a milk reservoir (not shown) to enable milk supply from the milk reservoir to the inlet 140.

Fig. 1 also shows a device 150 comprising an air channel 155 extending inside the housing 115 and connected to the hollow space 120, and an inlet 152, the air channel 155 being connected to the atmosphere surrounding the milk frothing device 1 through the inlet 152, such that air can enter the hollow space 120 through the inlet 152 and the air channel 155.

Fig. 1 also shows that the inlet 130 for supplying steam is realized in a steam nozzle 135, said steam nozzle 135 protruding into the hollow space 120, so that steam can be injected into the hollow space 120 through the inlet 130 via the steam nozzle 135. In order to form a connection between the device 110 and the output means 100 in a simple manner, the device 110 is provided with a tubular connection 160 which is connected to the hollow space 120 by a connection channel 162.

According to fig. 1, the emulsion chamber 15 comprises a fluid inlet 15-1 on the side of the output device 100, through which a fluid in the form of a mixture of, for example, milk, air and steam, can be introduced into the emulsion chamber 15. The shape of the connection 160 of the device 110 is such that it can attach the output means 100 to the connection 160 in such a way that: the portion of the output device 100 adjacent to the fluid inlet 15-1 is located directly above the connection 160.

To produce milk foam with the milk frothing apparatus 1, the connector 145 of the inlet 140 may be connected to the milk reservoir by a line, and the inlet 130 may be connected to a device for generating steam (not shown). When steam is injected into the hollow space 120 through the inlet 130 and the steam nozzle 135, a vacuum is generated in the hollow space 120 according to the venturi effect, thereby drawing in milk through the inlet 140 and air through the inlet 152 of the device 150, and the drawn-in milk and air are mixed with the injected steam in the hollow space 120. Thereby generating a milk-air-steam mixture which finally flows into the emulsion chamber 15 via the connecting channel 162, wherein the milk-air-steam mixture forms an emulsion in the form of milk bubbles in the emulsion chamber and is discharged from the emulsion chamber 15 via the lower outlet 61 of the outlet device 100.

In the exemplary embodiment shown, the emulsification chamber preferably comprises a first emulsification chamber portion 16, a second emulsification chamber portion 17 and a connecting channel 18 connecting the emulsification chamber portions 16, 17. The fluid inlet 15-1, the emulsification chamber 15, the first emulsification chamber portion 16, the connecting channel 18 and the second emulsification chamber portion 17 are arranged in series in that order along the longitudinal axis LA of the output device 100. Thus, fluid introduced into the emulsion chamber 15 through the fluid inlet 15-1 flows along the longitudinal axis LA of the output device 100 along the center of the emulsion chamber 15.

The cross-section of the connecting channel 18 (perpendicular to the longitudinal axis LA of the output device 100) is smaller than the cross-section of the emulsion chamber 15 in the first emulsion chamber part 16 or the second emulsion chamber part 17 (perpendicular to the longitudinal axis LA, respectively). Thus, the emulsifying chamber portions 16 and 17 form two separate spaces in the emulsifying chamber 15, which are in fluid communication with each other only through the connecting channel 18. The emulsifying chamber sections 16, 17 and the connecting channel 18 ensure a strong rotation of the fluid (presently a milk-air-steam mixture) introduced into the emulsifying chamber sections 16 and 17, so that an effective mixing of all components of the fluid, in particular the emulsification of milk and air, is achieved. It goes without saying that an emulsion of milk and air can also be formed by an emulsion chamber 15 which consists of only a single (extending over the entire length of the emulsion chamber 15) space.

The deflecting surface 58 is arranged downstream of the fluid inlet 15-1 and extends transversely to the longitudinal axis LA of said output device 100, so that the fluid introduced into the emulsifying chamber 15 and flowing along the longitudinal axis LA hits the deflecting surface 58, slowing down and homogenizing in the emulsifying chamber 15, so as to form a very homogeneous mixture of milk, air and steam in the emulsifying chamber 15. As will be described further below, a deflecting member 59 may be provided in addition to the deflecting surface 58.

It should be noted that the apparatus 110 may also be implemented in such a way: the supply of air through the air passage 150 may be interrupted as needed. In this case, when steam is supplied through the inlet 130, only the mixture of steam and milk reaches the emulsifying chamber 15 and may be dispensed from the output device 100 in the form of heated (hot) milk. Furthermore, milk can be pumped into the emulsion chamber 15 via the inlet 140. In this case, it is possible to convey the (cold or optionally heated) milk into the emulsifying chamber 15 without having to create a vacuum in the hollow space 120 on the basis of the venturi effect by introducing steam. It is therefore conceivable to completely eliminate the steam supply and to introduce only the mixture of milk (cold or heated) and air in the emulsifying chamber 15.

Fig. 1 also shows that, in the present embodiment, the output device 100 is composed of a plurality of parts: the output device 100 comprises at least two parts: the first (upper) part 10 and the second (lower) part 11 may be assembled as a unit (as shown in fig. 1) and separated from each other to facilitate thorough cleaning of the parts 10 and 11 as required. When the parts 10 and 11 are assembled into a unit as shown in fig. 1, they may be arranged in a sleeve 90, which sleeve 90 at least partly surrounds the parts 10 and 11 and thereby connects the parts 10 and 11 together, by: the parts 10 and 11 can again be removed from the sleeve 90 and separated from each other.

When the parts 10 and 11 are assembled into a unit, they comprise an emulsion chamber 15. In this embodiment, the first (upper) part is implemented in such a way that: it comprises a fluid inlet 15-1 of the emulsion chamber 15, in particular a first emulsion chamber portion 16 of said emulsion chamber 15, a connecting channel 18 and at least a part of a second emulsion chamber portion 17 of the emulsion chamber 15 (which is connected to the first emulsion chamber portion 16 by the connecting channel 18). Instead, the second (lower) part is implemented in such a way that: which at its lower end (when assembled with the first part 10 as shown in fig. 1) defines the second emulsion chamber portion 17 of said emulsion chamber 15 and comprises an output portion 55, said output portion 55 having an output opening 61 for dispensing the emulsion formed in the emulsion chamber 15, wherein at least one output channel 62, which is connected at one end to the second emulsion chamber portion 17 of the emulsion chamber 15 and at the other end to the output opening 61 of the output portion 55, is provided in said output portion 55, such that the emulsion can flow from the emulsion chamber 15 to the output opening 61 through said at least one output channel 62.

According to fig. 1, the outlet device 100 has a screen element arrangement 70, which in this embodiment comprises one screen element 70A, wherein the screen element 70A has a plurality of channels (not shown in fig. 1, but visible in fig. 2A, 2B and 2C) and is arranged in the region of the at least one outlet channel 62, so that emulsion flowing from the emulsion chamber 15 via the at least one outlet channel 62 to the outlet opening 61 has to pass the screen element 70A via the at least one channel.

According to fig. 1, in this embodiment the screen element 70A is arranged on the second (lower) part 11 of the output device 100 such that the screen element 70A extends substantially perpendicular to the longitudinal axis LA of the output device 100. Fig. 2A-2C collectively illustrate details of the screen element 70A and the second portion 11 of fig. 1.

With reference to fig. 2A-2C, the second portion 11 is realized in the form of a substantially cylindrical body extending along a longitudinal axis LA and having, on one end 11B, a longitudinal portion forming an output portion 55. The second portion 11 has, at its other end 11A opposite the end 11B, a longitudinal portion having a recess 50, the recess 50 extending from the end 11A along the longitudinal axis LA and thus having a lower end 50A, the lower end 50A being spaced from the end 11A of the second portion 11. In this embodiment, the output portion 55 is substantially the same as the longitudinal portion of the second portion 11, extending upwardly from the end 11B of the second portion 11 to the end 50A of the recess 50.

As shown, the recess 50 has an internal thread 60 formed therein. This internal thread 60 makes it possible to screw the second part 11 onto the first part 10, thereby connecting the second part 11 with the first part 10 (as shown in fig. 1), wherein this means that the second part has an external thread adapted (complementary) to the internal thread 60. The recess 50 of the second section 11 is directly adjacent the output section 55 and therefore forms part of the second emulsion chamber portion 17 of the emulsion chamber 15 when the first section 10 and the second section 11 are assembled into a unit (as shown in figure 1). In particular, the end 50A of said recess 50 forms the lower end of the second emulsifying chamber portion 17 of the emulsifying chamber 15.

In particular, fig. 2A and 2C show that the outlet opening 61 of said outlet portion 55 is realized on the end 11B of the second portion 11, wherein, in the present embodiment, its outer edge 61.1 has a circular shape. According to fig. 2A, the outlet opening 61 is defined by a lower edge of a boundary surface 61A, which boundary surface 61A extends substantially cylindrically around the longitudinal axis LA on the end portion 11B and is arranged substantially rotationally symmetrically with respect to the longitudinal axis LA.

Said boundary surface 61A extends up to the end 50A of the recess 50 along the longitudinal axis LA (starting from the end 11B of the second portion 11) and is therefore adjacent to the second emulsifying chamber portion 17 of the emulsifying chamber 15.

The deflecting member 59 is arranged in the centre of the output opening 61 and extends from the end 11B of the second portion 11 along the longitudinal axis LA to a distance from the boundary surface 61A. Thus, an annular intermediate space is formed between the deflecting member 59 and the boundary surface 61A, wherein said intermediate space is open towards the emulsion chamber 15 and thus forms a fluid communication between the emulsion chamber 15 and the output opening 61, such that fluid can flow from the emulsion chamber 15 to the output opening 61 via the intermediate space.

In the present embodiment, the deflecting member 59 is connected to the boundary surface 61A by a web 65, so that the deflecting member 59 is held in a fixed position with respect to the boundary surface 61A and the output port 61, respectively. In this case, three webs 65 are provided, wherein the webs 65 extend radially relative to the longitudinal axis LA in the intermediate space between the deflection member 59 and the boundary surface 61A. The web 65 thus divides the intermediate space between the deflecting member 59 and the boundary surface 61A into three separate regions, each region forming an output channel 62, one end of said output channel 62 being connected to the emulsion chamber 15 and the other end opening into the output 61, i.e. the fluid in the emulsion chamber 15 can in this case only flow through the output channel 62 to the output 61. In the present exemplary embodiment, the outlet channels 62 are substantially identical in size and each have a cross section (perpendicular to the longitudinal axis LA) in the form of a circular segment.

Fig. 1, 2A and 2B further show that the deflecting member 59 comprises on the distal end a (substantially) cylindrical portion 59.1 directed towards the output opening 61, wherein said cylindrical portion extends along the longitudinal axis LA and protrudes beyond the end 50A of the recess 50 and along the longitudinal axis LA into the second emulsion chamber portion 17 of the emulsion chamber 15 over at least a part of its length. In the present embodiment, the end face of the cylindrical portion 59.1 forms the (aforementioned) deflection surface 58, which has the function as described above.

According to fig. 1 and 2A-2C, in this embodiment the screen element 70A of the screen element arrangement 70 is a separate component that can be inserted into the second part 11. According to fig. 1 and 2A-2C, the screen element 70A is realized in the form of a perforated plate, which comprises a plurality of channels 71, and may be further configured to form: which is insertable into recess 50 of second portion 11 along longitudinal axis LA and is located on end 50A of recess 50. In the present embodiment, the screen element 70A is realized in the form of a (preferably flat) annular plate having a central hole 72. In this case, the shape of the aperture 72 is such that the cylindrical portion 59.1 of the deflecting member 59 can pass through the central aperture 72 when the screen element 70A is inserted into the recess 50 of the second portion 11. According to the arrangement in fig. 1 and 2A-2C, the screen element 70A is located on an end 50A of the recess 50 in a manner extending transversely with respect to the longitudinal axis LA, wherein the screen element is located on the deflecting member 50 in such a manner that: at least a part of the length of the cylindrical portion 59.1 protrudes through the central hole 72 and thus beyond the screen element 70A into the second emulsion chamber portion 17 of the emulsion chamber 15. In this case the shape of the central hole 72 is adapted to the shape of the cylindrical portion 59.1 so that the screen element 70A is held in a stable position (as described above) when the screen element 70A is inserted into the recess 50 of the second part 11. In this position, the channel 71 extends substantially parallel to the longitudinal axis LA.

It should also be noted that according to fig. 1 and 2A, the cylindrical portion 59.1 protrudes through the central hole 72 into the second emulsion chamber portion 17 of the emulsion chamber 15 by such a distance that the deflecting surface 58 is spaced apart from the screen element 70A (seen in the direction of the longitudinal axis LA). This arrangement of the deflection surface 58 has the following advantages: the emulsion of milk and air flowing in the direction of the deflecting member 59 along the longitudinal axis LA is rotated very strongly when it hits the deflecting surface 59 in the second emulsion chamber portion 17, so that a particularly homogeneous emulsion can be obtained (as described above).

According to fig. 1 and 2A-2C, in the present embodiment the screen elements 70A of the screen element arrangement 70 are arranged at the distal end of the output channel 62 with respect to the output opening 61 and extend substantially perpendicular to the longitudinal axis LA, and such that the screen elements 70A on the end 50A of the recess 50 completely cover the intermediate space between the boundary surface 61A and the deflecting member 59. Thus, fluid flowing from the emulsion chamber 15 to the output port 61 must first pass through the screen element 70A via the channel 71 and then flow through the one or more output channels 62 in order to reach the output port 61.

In this embodiment, the channels 71 have a circular cross-section and extend longitudinally parallel to each other (or parallel to the longitudinal axis LA of fig. 1 and 2A) substantially perpendicular to the surface of the screen element 70A. The diameter d of the channel 71 is 0.1-1.5mm, and the length of the channel 71 is 0.1-1.5 mm.

If emulsion in the form of milk foam flows in this case from the emulsion chamber 15 to the outlet 61, it flows through the channel 71 in such a way that: there is a stretching flow at least in certain areas of the flow, wherein the stretching flow is adapted to divide the emulsion droplets and air bubbles contained in the fluid into smaller emulsion droplets and air bubbles, so that the emulsion (as described above) is dispensed from the outlet opening 61 in the form of milk bubbles with particularly small emulsion droplets and air bubbles.

It should be noted that in the context of the present invention, the cross-section of the channel 71 is not necessarily circular, but may have any shape (e.g. circular or having one or more corners).

The foregoing description regarding the diameter d of the passage 71 (if the passage 71 has a circular cross-sectional area) may be generalized to passages 71 having cross-sections that deviate from a circle. In this case, the description of the so-called "hydraulic diameter" can be used to characterize the "size" of the cross-section of the channel 71 having a cross-section of any shape.

The hydraulic diameter d_hIs a mathematical factor that can be used to calculate the pressure loss and flow in a pipe or channel if the cross-section of the pipe or channel deviates from a circular shape. The use of hydraulic diameters represents a good approximation of turbulence. Flow conditions have been widely documented for pipes and channels having a circular cross-section. In flow channels with arbitrary cross-sections, the calculation of the hydraulic diameter is used to determine the inside diameter of a circular pipe of the same length, the same average flow velocity and with the same pressure loss as a given flow channel. The definition of hydraulic diameter is based on the idea that: comparable conditions exist if the cross-sectional area a of each flow channel is proportional to the wetted perimeter U. With respect to the cross-sectional area of the flow channel, the term "wetted perimeter" refers to the length of the curve of fluid flow through the flow channel in contact with the wall of the flow channel, respectively. Thus, the hydraulic diameter d_hIs defined by the formula:

thus, in a flow channel having a circular cross-section with a diameter d, the hydraulic diameter d_hD. In a flow channel with a square cross section with a side length a, the hydraulic diameter d_h＝a。

Hydraulic diameter d, regardless of the cross-sectional shape of the channel 71_hAnd length of channel 71The degree should be embodied in such a way that: hydraulic diameter d of the channel 71_h0.1-1.5mm and the length of the channel 71 is 0.1-1.5 mm. As mentioned above, the hydraulic diameter d of the channel 71 may also be_hAnd the length L specifies other ranges (within the above ranges) so that the milk foam dispensed from the output device 100 is optimized in its consistency.

For example, the channels of the at least one screen element 70A may be realized in such a way with respect to the cross section of the respective channel: i.e. the hydraulic diameter d of the channel 71_hPreferably 0.1 to 1.0mm, particularly preferably 0.3 to 0.9 mm. Furthermore, the channels of the at least one screen element 70A may be implemented in such a way with respect to the length of each channel: the length of the channels is preferably 0.15 to 1.0mm, particularly preferably 0.15 to 0.9 mm. For example, the passage of the at least one screen element 70A may be achieved in such a way: hydraulic diameter d_hThe length ratio to the channel is greater than 1:1.5, preferably greater than 1:1.25 and less than 4:1, particularly preferably greater than 1:1.25 and less than 3: 1.

As mentioned above, in the embodiment shown in fig. 1 and 2A-2C, the screen element 70A of the screen element arrangement 70 is a separate component that may be inserted into the second portion 11. This has the advantage that the screen element 70A and the second portion 11 may be made of different materials and that different manufacturing methods may be used to manufacture the screen element 70A and the second portion 11, respectively. Thus, the screen element 70A and the second portion 11 may be optimized independently of each other, if applicable, according to different criteria. Furthermore, the screen element 70A and the second portion 11 may be separated from each other, for example, to clean only the screen element 70A independently of the second portion 11 (and, if applicable, cleaning agents that are incompatible with the material of the second portion 11) or, in the event of a defect, to replace the screen element 70A with a corresponding new screen element.

The second part 11 may be made of, for example, plastic and may be manufactured using conventional and particularly inexpensive methods of manufacturing plastic parts, such as injection molding. Instead, the screen elements 70A may be formed from a metallic materialConstructed and realized in the form of, for example, (metal) porous plates. Such a perforated plate can be made of a metal plate which on the one hand has a small thickness and on the other hand has a sufficiently high mechanical stability due to the use of metal material. In this case, the passage 71 may be manufactured by a method of machining a thin metal plate, by which a corresponding metal plate may be formed with a plurality of through-holes, which may respectively have a small diameter (e.g., close to the hydraulic diameter d of the passage 71 as described above)_hLower limit value of) and is closely disposed between the two passages.

Alternatively, according to the embodiments shown in fig. 1 and 2A-2C, the screen elements 70A of the screen element arrangement 70 may also be realized in the form of a screen structure, for example, in the form of a woven or braided structure of interwoven metal wires or fibers, preferably plastic, wherein the channels are realized in a "meshed" manner, i.e. they are formed between metal wires or fibers, respectively, which are interconnected in a meshed manner.

A second embodiment of the output device 100 is described below with reference to fig. 3 and 4A-4C. The second embodiment of the output device 100 shares many features in common with the output device 100 of fig. 1 and 2A-2C. Accordingly, components having the same or similar functions are identified with the same reference numerals as in fig. 1, 2A-2C, 3, 4A-4C, respectively, wherein the above description of the embodiment of the output device 100 in fig. 1 and 2A-2C is similarly applicable to the second embodiment of the output device 100 in fig. 3 and 4A-4C.

The two embodiments of the output device 100 of figures 1, 2A-2C and figures 3, 4A-4C differ substantially only in the details of the construction of the screen element arrangement 70.

In fig. 1 and 2A-2C, the screen element arrangement 70 of the output arrangement 100 comprises only a single screen element 70A, but it is basically also possible that the screen element arrangement 70 comprises two or more screen elements. If the screen element arrangement 70 comprises a plurality of screen elements, they are preferably arranged in series one behind the other, so that the emulsion flowing to the outlet opening 61 has to pass each screen element at a time via a passage passing successively through the different screen elements.

Fig. 3 and 4A-4C illustrate an embodiment of a screen element arrangement 70 that includes two screen elements 70A and 70B. According to this embodiment, the screen elements 70A and 70B must be separate components that can be inserted into the second portion 11 of the output device 100, respectively, and if applicable, removed again. With respect to its construction, the screen element 70A of FIGS. 3 and 4A-4C is the same as the screen element 70A of FIGS. 1 and 2A-2C. In this embodiment, the screen element 70B has substantially the same structure as the screen element 70A, and is therefore realized, like the screen element 70A, in the form of a (preferably flat) annular plate with a central hole. The second screen element 70B is particularly shaped to be able to pass through the output openings 61 of the second portion 11 and to be located in an intermediate space between, for example, the deflecting member 59 (as described above) and the boundary surface 61A. The size of the central aperture of the screen element 70B may be such that the deflecting member 59 fits specifically into the aperture.

In the screen element arrangement 70 of fig. 3 and 4A-4C, the screen elements 70A and 70B are each positioned to extend generally perpendicular to the longitudinal axis LA. In this case, the channels 71 of the screen elements 70A and 70B extend substantially parallel to the longitudinal axis LA.

The screen elements 70A of the screen element arrangement 70 of fig. 3 and 4A-4C are arranged in the same way as the screen elements 70A of the screen element arrangement 70 of fig. 1 and 2A-2C, i.e. at the distal end of the output channel 62 towards the output opening 61, so that the screen elements 70A located on the end 50A of the recess 50 completely cover the intermediate space between the boundary surface 61A and the deflecting member 59. In this embodiment, the screen element 70B is located in an intermediate space (as described above) formed between the deflecting member 59 and the boundary surface 61A, such that the screen elements 70A and 70B are spaced apart from each other in the direction of the longitudinal axis LA and are therefore separated by the intermediate space in the direction of the longitudinal axis LA. In this embodiment, the screen elements 70A and 70B are provided on opposite sides of a web 65, which web 65 connects the deflecting member 59 to the boundary surface 61A and separates the output channels 62 from each other. Thus, the distance between the screen elements 70A and 70B is at least the same as (or greater than) the dimension of the web 65 in the direction of the longitudinal axis LA. This distance is generally from 0.1 to 20mm, preferably from 0.5 to 2.5mm, particularly preferably from 0.9 to 1.2 mm.

The emulsion flowing from the emulsion chamber 15 through the outlet channel 62 to the outlet opening 61 flows substantially along the longitudinal axis LA and, in the process, passes through the screen elements 70A and 70B in sequence via the respective channels 71 of the screen elements 70A and 70B.

As the emulsion flows through the passages 71 of the screen elements 70A and subsequently through the passages 71 of the screen elements 70B, the emulsion droplets and air bubbles contained therein are separated into smaller emulsion droplets and smaller air bubbles (due to the formation of a elongational flow in the passages of the screen elements 70A, 70B).

The intermediate space between the screen elements 70A and 70B has other effects: the emulsion flows through this intermediate space in a turbulent flow, decelerating on the screen element 70B after the emulsion passes the screen element 70A. This causes the emulsion to rotate within the intermediate space and smoothes the flow within the intermediate space, thus improving the uniformity of the spatial distribution of emulsion droplets and air bubbles in the emulsion by the flow within the intermediate space between screen elements 70A and 70B.

A third embodiment of the output device 100 is described below with reference to fig. 5, 6A, and 6B. The third embodiment of the output device 100 shares many features in common with the output device 100 of fig. 1 and 2A-2C. Accordingly, components having the same or similar functions are identified with the same reference numerals in FIGS. 1, 2A-2C, 5, 6A, and 6B, wherein the above description of the embodiment of the output device 100 of FIGS. 1 and 2A-2C is similarly applicable to the third embodiment of the output device 100 of FIGS. 5 and 6A and 6B.

According to fig. 5, 6A and 6B, the output device 100 comprises a screen element arrangement 70 with a single screen element 70A, wherein the screen element arrangement 70 is realized in the form of an integral part of the second part 11 of the output device 100, i.e. the screen element arrangement 70 or the screen element 70A and the second part 11 may be made in one piece. For example, the second part 11 and the screen element arrangement 70 may be constructed from plastic, for example by an injection molding process, thereby enabling inexpensive manufacture

According to fig. 5, 6A and 6B, the second portion 11 has in particular a one-piece outlet portion 55, which in the present embodiment is constituted by a longitudinal portion of the second portion 11, which extends along the longitudinal axis LA between an end 11B of the second portion 11 and an end 50A of the recess 50 of the second portion 11 and comprises the outlet opening 61. The output portion 55 further comprises a deflecting member 59, which deflecting member 59 is located in the center of the output opening 61 and extends from the output opening 61 along the longitudinal axis LA to a distance from the boundary surface 61A, so that an intermediate space is formed between the deflecting member 59 and the boundary surface 61A, which intermediate space extends substantially annularly along the longitudinal axis LA and the deflecting member 59. The screen element 70A is arranged in this intermediate space towards the distal end of the outlet opening and on the end 50A of the recess 50 of the second part 11, i.e. in the form of a part of the second part 11 extending between the deflecting member 59 and the boundary surface 61A, and rigidly connects the deflecting member 59 to the boundary surface 61, so that the deflecting member 59 is held in a stable position relative to the boundary surface 61A and the outlet opening 61.

In the present embodiment, said deflecting member 59 is connected to the boundary surface 61A by means of the screen element 70A in such a way that the deflecting member 59 and the screen element 70A together form a planar boundary surface on the end 50A of the recess 50, wherein said planar boundary surface defines the recess 50 at its end 50A. The deflecting surface 58 is in this case formed by a central area of the boundary surface, which central area is arranged on (or in the centre of) said longitudinal axis LA, wherein the surface of the screen element 70A facing the recess 50 extends annularly around said deflecting surface 58 and abuts radially flush (without a step) with the deflecting surface 58. Due to this arrangement, the deflecting surface 58 has the effect of: the emulsion flows through the emulsion chamber 15 in a longitudinal axial direction, hits the deflection surface 58 and is thereby decelerated on the deflection surface 58 and rotates in the emulsion chamber.

The screen element 70A includes a plurality of channels 71 extending substantially parallel to the longitudinal axis LA and having a circular cross-sectional area. Said channels 71 are evenly distributed around the deflecting surface 58 in a space extending annularly around the deflecting surface 58 or the deflecting member 59, so that they open into an intermediate space between the deflecting member 59 and the boundary surface 61A. The hollow space is thus in fluid communication with the emulsion chamber 15 and the output 61 and forms a (single) output channel 62 via which the emulsion can flow from the emulsion chamber 15 to the output 61. 6A-6B according to FIG. 5, the outlet channel 62 of the outlet device 100 extends along the longitudinal axis LA such that it encircles the deflecting member 59 in the area between the screen element 70A and the outlet openings 61. In this way, it is ensured that the milk foam produced in the output device 100 is distributed via the output opening 61 in the form of a jet having a circular cross section and being uniform over the entire extent of the cross section.

Fig. 7 shows another embodiment of the output device 100. This embodiment differs from the output device of figures 5, 6A and 6B in that the details of the construction of the second portion 11 are different. Fig. 7 therefore shows only the differences in perspective view of the second part 11 from the output device 100 in fig. 5, 6A and 6B.

In the embodiment of fig. 7, the deflecting member 59 is connected to the boundary surface 61A by means of the screen element 70A in such a way that the deflecting member 59 and the screen element 70A together form a boundary surface on the end 50A of the recess 50, wherein the boundary surface defines the recess 50 on its end 50A. In this case, the deflection surface 58 is formed with a central region of this boundary surface, which is arranged on the longitudinal axis LA (or substantially in its center), wherein in the present embodiment said deflection surface is realized on an end face of the deflection member 59 facing the recess 50 (or facing away from the output opening 61).

The surfaces of the screen elements 70A facing the recesses 50 extend annularly around the deflecting surface 58 and the deflecting member 59, respectively. However, in contrast to the output device 100 of fig. 5, 6A and 6B, the surface of the screen element 70A facing the recess 50, without a step, does not radially abut the deflecting surface 58. Said deflecting member 59 extends slightly along the longitudinal axis LA such that a longitudinal section of the deflecting member 59 protrudes beyond the screen element 70A in the longitudinal direction LA (starting from the end 50A of the recess 50) towards the end 11A of the second part 11. In this case, the deflection surface 58 is arranged at a distance from the surface of the screen element 70A, which surface faces the recess 50 and is arranged in particular upstream of the screen element 70A (referring to the direction of flow of the fluid from the fluid inlet 15-1 to the outlet opening 61). This design of the deflecting member has the effect that: the fluid flowing along the longitudinal axis LA in the direction of the output opening 61 is very strongly rotated in the vicinity of the deflecting member 59.

In the embodiment of fig. 1-7, the respective screen elements 70A and 70B of the screen element arrangement 70 are generally flat planar bodies, i.e. the screen elements 70A and 70B each extend along a plane (at least in the area where the channels 71 are provided), wherein opposite sides of the respective screen element 70A or 70B are defined by planes arranged parallel to each other and the channels 71 preferably extend perpendicular to these planes.

It should be noted that the present invention is not limited to screen elements having a planar body shape. The respective screen element should generally be shaped: which separates two opposite spaces from each other (at least in the area where the channel is provided), wherein the channel forms a fluid communication between the two opposite spaces. The respective screen element may thus be, for example, curved or arched or realized with a structure that is extended along the contour (or at least one region of the contour) of a cylinder, cone, truncated cone, cube, cuboid, tetrahedron or the like in at least one region provided with said channels.

An embodiment of a screen element arrangement comprising at least one non-planar screen element is shown in fig. 8. The output device 100 shown in fig. 8 has a structure substantially corresponding to the output device 100 of fig. 1 and 3. In fig. 8, the illustrated output device 100 includes a screen element arrangement 70 having two screen elements, namely a screen element 70A and a screen element 70B. With respect to its construction, the screen element 70A of FIG. 8 is identical to the screen element 70A of FIGS. 1, 2A-2c and FIG. 3. Thus, the screen element 70A in fig. 8 is a flat planar body having a plurality of channels 71. According to fig. 8, in this embodiment the screen element 70A is shown arranged on the distal end of the deflecting member 59 remote from the output opening 61, such that said screen element 70A is arranged on the deflecting member 59, wherein said screen element extends substantially perpendicular to the longitudinal axis LA, such that the screen element 70A completely covers the intermediate space between the boundary surface 61A and the deflecting member 59.

According to fig. 8, the screen element 70B is arranged in the emulsion chamber 15 upstream of the screen element 70A such that the screen element 70B is spaced apart from the screen element 70A. In the present embodiment, the sieve element 70B is arranged in the region of the first emulsion chamber portion 16 of the emulsion chamber 15 and extends transversely to the longitudinal axis LA over the entire cross-section of the emulsion chamber 15, so that the milk-air-steam mixture can optionally flow into the emulsion chamber 15 via the connecting channel 162 and the fluid inlet 15-1, or the milk-air-steam mixture forming emulsion containing milk and air upstream of the sieve element 70B must first pass the sieve element 70B before reaching the intermediate space between the sieve element 70B and the sieve element 70A.

In the embodiment of fig. 8, the sieve element 70B forms a container with a container wall which has a cylindrical shape in the region (and comprises the channel), i.e. one region of the sieve element 70B extends along the contour of the cylindrical region (in particular along the curved region and the end face of the cylinder) and thus comprises a region 70B-1 which is realized in a planar manner and extends along the end face of the cylinder and a region 70B-2 which is connected to the region 70B-1 and extends along the curved region of the cylinder. In this embodiment, the screen elements 70B are positioned and shaped in such a way that: the area 70B-1 of the screen element 70B extends substantially perpendicular to the longitudinal axis LA and the area 70B-2 of the screen element 70B extends around the longitudinal axis LA at a distance from the longitudinal axis LA. For example, the regions 70B-1 and 70B-2 may be implemented rotationally symmetric with respect to the longitudinal axis LA (as shown in FIG. 8).

The screen element 70B includes a plurality of channels (not shown in fig. 8) through which a milk-air-steam mixture or emulsion containing milk and air can flow. These channels may be formed in the area 70B-1 and/or in the area 70B-2, wherein the channels formed in the area 70B-1 preferably extend in a direction substantially perpendicular to the longitudinal axis LA, and the channels formed in the area 70B-2 extend radially with respect to the longitudinal axis LA. If the passage is formed in the area 70B-2 of the screen element 70B, the screen element 70B is preferably shaped and arranged in the emulsion chamber 15 such that an intermediate space 16-1 extending annularly around the area 70B-2 of the screen element 70B is formed between the area 70B-2 of the screen element 70B and the surface of the upper part 10 of the output device 100 defining the emulsion chamber 15. In this way, it is ensured that the milk-air-steam mixture passing through the sieve element 70B via the passage formed in the area 70B-2 can flow in the direction of the longitudinal axis LA through the intermediate space 16-1 to the sieve element 70A.

In the embodiment shown in fig. 8, the screen elements 70B and 70A are typically spaced apart by a distance of 0.1 to 20 mm. The intermediate space between the screen elements 70A and 70B shown has other effects as well: the emulsion flows through this intermediate space in the form of turbulence, which after passing through the screen element 70B decelerates over the screen element 70A. This causes the emulsion to rotate within and flow smoothly within the intermediate space, so that the flow through the intermediate space between the screen elements 70A and 70B improves the uniformity of the spatial distribution of the emulsion droplets and bubbles.

Claims (16)

1. An output device (100) for a milk frothing apparatus (1), comprising:

an emulsification chamber (15) having a fluid inlet (15-1) for introducing a fluid containing milk, air and/or steam into the emulsification chamber (15), wherein the fluid is emulsified in the emulsification chamber (15) to form an emulsion in the form of milk bubbles; and

an output portion (55) having an output opening (61) for dispensing the emulsion flowing out of the emulsion chamber (15), wherein the output portion (55) comprises at least one output channel (62) in fluid communication with the emulsion chamber (15) and the output opening (61) such that the emulsion can flow from the emulsion chamber (15) to the output opening (61) via the at least one output channel (62);

wherein the output portion (55) is further provided therein with a deflecting surface (58) and/or at least one deflecting member (59) decelerating and rotating the fluid introduced into the emulsion chamber (15);

the method is characterized in that:

a sieve element arrangement (70) with at least one sieve element (70A, 70B) is also provided, wherein the sieve element (70A, 70B) comprises a plurality of channels (71) and the sieve element (70A, 70B) is arranged upstream of the output opening (61) such that emulsion from the emulsion chamber (15) has to pass the at least one sieve element (70A, 70B) via at least one of the channels (71) to the output opening (61); and

the hydraulic diameter (d) of the channel (71)_h) Is 0.1-1.5mm, and the length of the channel (71) is 0.1-1.5 mm;

the channel (71) of the at least one screen element (70A, 70B) is arranged in a space extending annularly around the deflection surface (58) and/or at least one deflection member (59).

2. The output device (100) of claim 1, wherein: the deflection surface and/or at least one deflection member (59) is arranged in a central region of the output opening (61).

3. The output device (100) according to claim 1 or 2, characterized in that: the ratio of the hydraulic diameter to the length of the channel (71) is greater than 1:1.5, preferably greater than 1:1.25 and less than 4: 1; more preferably greater than 1:1.25 and less than 3: 1.

4. The output device (100) according to any one of claims 1-3, wherein: the at least one screen element (70A, 70B) is arranged upstream of the output opening (61) at a distance from the output opening (61).

5. The output device (100) according to any one of claims 1-4, wherein: the at least one screen element (70A, 70B) is embodied as planar or curved or arched or extends along the contour of a cylinder, cone, truncated cone, cube, cuboid or tetrahedron in at least one region in which the channel (71) is provided.

6. The output device (100) according to any one of claims 1-5, wherein: the number of channels (71) is at least 10, preferably 20 to 300, more preferably 25 to 200, particularly preferably 30 to 160.

7. The output device (100) according to any one of claims 1-6, wherein: the channels (71) are realized in a circular, angular or net-like manner.

8. The output device (100) according to any one of claims 1-7, wherein: the channels (71) are arranged to: two adjacent channels (71) are spaced from each other by 0.1-1.5mm, preferably 0.1-1.0mm, more preferably 0.3-0.9 mm.

9. The output device (100) according to any one of claims 1-8, wherein: the at least one screen element (70A) and the output section (55) are realized in an integrated manner.

10. The output device (100) of claim 9, wherein: the at least one screen element (70A) is manufactured by an injection molding process.

11. The output device (100) according to any one of claims 1-10, wherein: the at least one outlet channel (62) is substantially annular or has the shape of a circular ring segment in cross-section.

12. The output device (100) according to any one of claims 1-11, wherein: the screen element arrangement (70) comprises at least two screen elements (70A, 70B).

13. The output device (100) of claim 12, wherein: the at least two screen elements (70A, 70B) are arranged behind each other with respect to the flow direction of the emulsion and at a distance in the flow direction of the emulsion, wherein the distance is 0.1-20mm, preferably 0.5-10mm, more preferably 0.9-5 mm.

14. The output device (100) according to any one of claims 1-13, wherein: the at least one screen element (70A, 70B) is arranged to: in the emulsion chamber (15), at a distal end of the at least one outlet channel (62) with respect to the outlet opening (61) or in the at least one outlet channel (62).

15. The output device (100) according to any one of claims 1-14, wherein: the emulsification chamber (15) comprises a first emulsification chamber portion (16), a second emulsification chamber portion (17) and a connecting channel (18) forming a fluid communication between the first emulsification chamber portion (16) and the second emulsification chamber portion (17); wherein the content of the first and second substances,

the first emulsifying chamber portion (16) adjoins the fluid inlet (15-1) and the at least one outlet channel (62) is introduced into the emulsifying chamber (15) in the region of the second emulsifying chamber portion (17).

16. A milk frothing apparatus (1) comprising:

the output device (100) of any one of claims 1-15; and

a device (110) for introducing milk, air and/or steam into an emulsion chamber (15) of the output device (100).