HK1213161B - Device for preparing mulk froth that can be optionally hot or cold, or for dispensing optionally hot or cold milk - Google Patents

Description

Device for preparing milk foam with optional heating and cooling or for dispensing milk with optional heating and cooling

Technical Field

The invention relates to a device for preparing milk foam with optional cold and hot contents or for dispensing milk with optional cold and hot contents.

Background

According to the prior art, coffee-making appliances, in particular espresso coffee machines, are often equipped with a milk-froth preparation device which comprises, as a main component, a frothing apparatus with a flow passage configured as a venturi nozzle. The flow path is connected to a milk conduit into which an air intake conduit or opening opens for the preparation of a milk foam. For preparing milk foam, steam is fed from a steam generator of the coffee-making appliance to a flow path of the frothing device, which is designed as a venturi nozzle, and a negative pressure is generated in the flow path by the flow of the steam, which negative pressure sucks in milk from the milk container through the milk conduit and sucks in air through the air supply. Thereby mixing the steam, milk and air in the flow path and generating hot milk froth. The production of foam is stopped in the flow path of the frothing device by closing the air supply and only hot milk is prepared.

It is also well known that: in a device, a hot milk foam or a hot milk drink is prepared by sucking milk from a container by a pump and, during the suction, conducting the milk through a continuous heater and simultaneously heating it, and then conveying it via a throttle point to an outlet (EP 1593330 a 2). To prepare the foam, the milk flowing through the suction duct is mixed with air from the air supply duct. For cleaning the continuous heater and the conduits connected thereto (in particular the intake conduit of the device and the discharge conduit leading to the discharge), cleaning fluid can be introduced from an external supply source through a cleaning valve into a section of the intake conduit. At the beginning of this section of the intake line, a further valve with a receiving container or a discharge is provided, through which the cleaning liquid or water can flow out of the intake line. However, the section of the suction line adjacent to the milk container, in particular extending into the milk container from above, cannot be flushed thereby, since the cleaning liquid is not allowed to flow into the milk container. This is prevented by at least one check valve in the suction conduit. This section of the suction conduit has to be removed from the milk container for rinsing and subjected to a separate rinsing process. The milk container can be replaced.

Recently, apparatuses for preparing milk foam have been required which are capable of not only producing hot milk foam but also delivering cold milk foam. For this purpose, cold milk is pumped from a storage container into the frothing unit by means of a delivery pump, and either air which causes frothing is sucked in through an air supply line which opens into the milk line and in which a negative pressure is generated by the flow rate of the milk, or air is delivered to the milk via an air line by means of an overpressure generated by the pump. The milk can only be mixed with air in the milk line or in the milk frothing device.

It is also well known that: hot or cold foam can be produced alternatively in the same milk foam preparation device. In order to produce hot milk foam or just hot milk, the milk supplied by means of the pump or the milk-gas mixture supplied to the frothing device can be conducted through a heat exchanger upstream of or in the frothing device.

In a known device for producing foamed milk or milk drinks of this type, milk is sucked in from a container and conveyed to an outlet as required by means of a pump, wherein the milk can be mixed with air and the resulting milk-air mixture can be processed in the cold or hot state through a throttle point into foamed milk, provision being made for the device to: the milk-air mixture is optionally delivered to the discharge, either directly or by means of a continuous heater of the apparatus (WO 2008/083941 a 1). In detail, the milk inlet, which connects the milk container to the cold frothing device via the milk valve passage, has for this purpose in particular at least one section of the milk suction conduit which projects into the milk container. The milk intake conduit leads to a pump through a valve that can switch the milk intake conduit to another container. The discharge line downstream of the pump has two parallel sections which are arranged between the throttle point and the discharge and are selectively connected by a valve, wherein only one of the parallel sections is provided with a continuous heater. It is thus possible to convey cold or hot milk froths to the discharge. The device for producing foamed milk or milk drinks can be designed as a separate device or as a component of a coffee machine. The apparatus may be cleaned similarly to the apparatus described in EP 1593330 a2 above.

Disclosure of Invention

The object of the present invention is to provide a compact, robust and efficient device for selectively preparing hot and cold milk foam or delivering hot and cold milk, which is distinguished by a lower cost and an optimal cleaning while reducing the need for cleaning.

The invention accordingly proceeds from a device for preparing optionally hot milk foam or delivering optionally hot milk, comprising: a milk container that can be removed from the apparatus; a milk inlet connecting the milk container via a milk valve passage with a cold frothing device activatable via an air valve passage; a discharge duct having a discharge portion, provided downstream of the foaming device; and possibly a selectively activatable mechanism for warming the milk foam prepared in the frothing device or the milk flowing through the cold frothing device. The cold frothing device can in particular have a throttle section or throttle through which the milk mixed with air for frothing flows. Foam generation may begin downstream of the connection of the milk valve passageway with the air valve passageway. A pump, in particular a suction pump, can be provided for conveying milk through the milk inlet, the milk valve passage and the cold frothing device.

According to the invention, the milk container can be guided in a defined position in a device for preparing a cold-hot milk foam or for dispensing cold-hot milk, and has a milk plug valve at the bottom of the milk container. A complementary milk plug valve receptacle which is assigned to this milk plug valve is arranged as a milk inlet directly fixed on the milk valve passage, i.e. on a valve of the device and is designed in such a way that the milk plug valve engages in the complementary milk plug valve receptacle without problems and latches into it when the milk container is inserted. In this case, the complementary milk outlet valve receptacle is arranged in a stationary manner directly below the milk outlet valve of the milk container.

Whereby the milk flow path from the milk container inserted in the device up to the milk inlet of the milk valve path is minimized. In particular, the milk intake line or milk inlet line upstream of the milk inlet of the milk valve channel does not need to be flushed, for which purpose it is removed from the milk container and connected to an external cleaning fluid source (e.g., a flushing fluid container) and then reinserted into the milk container. The hygiene of the milk circuit can thus be improved with a simplified handling of the device.

In order to guide and position the milk container accurately, the device for preparing a cold-hot milk foam or for dispensing cold-hot milk comprises a housing base on which a milk container receiving chamber is fixedly arranged and into which the milk container can be inserted from above by way of guidance, such that the milk plug valve engages on the bottom of the milk container in a positionally fixed, complementary milk plug valve receiving portion which is directly connected to a milk inlet on the milk valve channel or the valve and is latched therein. A reliable sealing connection between the milk plug valve of the milk container and the complementary milk plug valve receptacle on the housing base of the device is thus ensured.

In particular, the milk container receiving chamber is connected in a planar heat-conducting manner to the cold side of the peltier element, wherein the milk container rests tightly, but detachably, against the heat-conducting inner side of the milk container.

For supplying the peltier element, the housing base can expediently have a supply connection and an activation contact which can be operated by an insertable milk container and by means of which the supply device of the peltier element is activated when the milk container is inserted into the milk container receiving chamber on the base. This ensures that the milk in the milk container is cooled as automatically as possible.

In a development of the device for producing milk foam or delivering milk, the rinsing liquid container receptacle is fixedly arranged on the housing base and is connected in a thermally conductive manner to the hot side of the peltier element, and the rinsing liquid container, which has a rinsing liquid insertion valve on the bottom, can be inserted into the rinsing liquid container receptacle by means of a guide, said valve being inserted into a complementary rinsing liquid valve receptacle when the rinsing liquid container is inserted into the rinsing liquid container receptacle. The complementary flushing-liquid plug-in valve receptacle is connected in a fluid-conducting manner to the flushing-liquid inlet of the flushing-liquid valve channel in order to be able to clean the lines and components of the device downstream of the flushing-liquid valve channel, if necessary. Since the rinsing liquid is warmed in an energy-efficient manner by the peltier element which is switched on for cooling the milk container, a good rinsing and cleaning effect of the rinsing liquid can be expected.

The heat-conducting connection of the peltier element, on the one hand, to the milk container receiving space and, on the other hand, to the rinsing liquid container receiving space can be realized in an efficient and structurally simple manner in that the peltier element is arranged between the milk container receiving space and the rinsing liquid container receiving space in a heat-conducting manner.

In a particularly compact embodiment of the device for preparing milk foam with selectable cold or hot output of milk, a multiway valve is provided in the housing base of the device, which multiway valve comprises: a milk valve passage with a complementary milk plug valve receptacle on the milk inlet; an air valve passage; an outlet of the multi-way valve; and a flushing liquid valve passage through which a flushing liquid conduit can be connected to the multi-way valve outlet.

The multiple-way valve is designed in particular such that in a first position it connects the multiple-way valve outlet to the milk inlet or the milk plug valve receptacle or in a second position it connects the multiple-way valve outlet to the milk inlet and to the air inlet on the air supply line, so that air is mixed into the milk by means of the negative pressure generated by the flowing milk or under the action of the pump in order to generate milk foam. In the third position of the multi-way valve, its multi-way valve outlet is connected to its flushing liquid inlet, so that flushing liquid is fed to the pump, the cold foaming device, the discharge conduit and the discharge, since the pump and the cold foaming device are arranged in flow relationship between the multi-way valve outlet and the discharge conduit.

It is advantageous in space if, in addition to the pump and the cold-producing device, an electric drive of the multi-way valve and of the pump is provided in the housing base, and if appropriate also an internal control unit of the multi-way valve and of the pump.

Alternatively, the drive means may be controlled manually, simply by a switch means.

In a development of the internal control units, these internal control units can have interfaces for wireless or wired connection to the central control unit for central control of the drive devices of the multi-way valve and of the pump, in particular with the control unit of the beverage preparation appliance.

In the device for preparing optionally hot milk foam or for dispensing optionally hot milk, the cold frothing arrangement can be simply designed as a throttle, in particular as a throttle section.

In the device for preparing cold-hot selectable milk foam or for dispensing cold-hot selectable milk, the outlet on the outlet line comprises in a single manner a steam heating device with a steam generator coupling as a selectively activatable means for warming milk foam prepared in or flowing through a cold frothing device of the device, the steam heating device being configured in such a way that the outlet is adapted by means of the steam heating device to warm cold milk foam or cold milk prepared in or dispensed by the cold frothing device in such a way that: the steam is fed into the steam generator coupling by an external steam generator or a steam outlet conduit of the steam generator.

In case the steam generator coupling is not connected to an external steam generator, the device may prepare cold milk foam or output cold milk. The device can be used as a simple unit which can be used independently. In order to operate the device as a separate appliance in an uncoupled state, in which the appliance can deliver cold milk foam or cold milk, the steam generator coupling can be closed, and it is particularly expedient if the steam generator coupling is automatically closable when it is or has been disconnected from the external steam generator or its steam line.

When it is desired to be able to prepare hot milk froth or hot milk selectively, the steam generator coupling means may be connected with an external steam generator or a steam outlet conduit in order to activate the steam heating means of the outlet and thus warm the milk froth or milk which is then output from the outlet, if necessary by a steam supply. Since the milk foam or milk is only warmed in the discharge section, no heat loss occurs in the discharge duct. In this way, no steam generator is provided in the device for producing hot milk foam or hot milk, and only the steam generator coupling of the outlet of the device is available at a much lower cost for coupling to an external steam generator having a complementary steam generator coupling.

In other words, the mechanism for preparing hot milk foam or hot milk is complete when the steam generator coupling means are coupled directly on the external steam generator or indirectly with an external steam generator outside the stand-alone device. In order to perform the warming function, the steam generator coupling is no longer closed, but is opened.

The outlet or its steam heating device can be designed in a simple manner as a mixer, in which the cold milk foam conveyed mixes with the steam supplied by the steam generator coupling and in this way directly warms the mixture.

However, if the prepared cold milk foam or cold milk is not to be brought into direct contact with the heated steam in order to remain as constant as possible in terms of its material composition during the warming process, it is also possible, instead of being designed as a mixer, to design the steam heating device of the outlet as a heat exchanger heated by externally generated steam, through which the prepared cold milk foam or cold milk flows.

A separate device for preparing optionally hot milk foam or for delivering optionally hot milk is particularly advantageously used in combination with a beverage preparation appliance, in particular a coffee beverage preparation appliance, for which purpose the steam generator coupling means of the outlet of the device for preparing optionally hot milk foam or for delivering optionally hot milk is coupled to a steam outlet conduit of a steam generator of the beverage preparation appliance, which steam outlet conduit is provided with a steam valve. When the steam generator coupling is coupled, a steam generator present within the beverage preparation appliance can also be used for producing hot milk foam or hot milk when the steam generator is switched on and a steam valve of a steam outlet conduit coupled with the device is controllably opened.

By supplying the steam generated by the powerful external steam generator via the steam generator coupling into the steam heating of the outlet of the device for preparing milk foam of optionally hot and cold or for dispensing milk of optionally hot and cold, the outlet can also adequately warm milk foam made of cold milk or cold milk that has been cooled beforehand.

The central control unit of the beverage preparation appliance also suitably controls a controllable steam valve in a steam outlet conduit of a steam generator of the beverage preparation appliance or controls the steam generator itself, wherein the steam outlet conduit may be coupled with a steam generator coupling of a device for preparing cold, hot, optionally milk frother cold, optionally milk. With the steam generator coupling coupled and the steam valve open, the steam generator in the beverage preparation appliance, to which the steam outlet conduit is connected, is effectively used for preparing hot milk froth or hot milk.

The coupling of the steam generator coupling means to the steam outlet conduit of the beverage preparation appliance can also be effected indirectly by means of a conventional frothing device of the beverage preparation appliance.

Detailed Description

The device for preparing cold-hot milk foam or for dispensing cold-hot milk comprises a housing unit having a housing base on which a milk container receiving chamber and a rinsing liquid container receiving chamber are arranged with a peltier element between them, so that the cold side of the peltier element is connected in a surface-heat-conducting manner to the milk container receiving chamber and the hot side of the peltier element lies in a surface-heat-conducting manner against the rinsing liquid container receiving chamber. Furthermore, the milk-containing container is thermally insulated from the rinsing liquid container.

The milk container can be inserted into the milk receiving chamber from above up to a lower end position, above which the milk container is located in the present example. In the lower end position of the milk container, the milk plug valve arranged in the bottom of the milk container projects into a complementary milk plug valve receptacle which acts directly as a milk inlet on the milk valve channel of the multi-way valve.

The rinse liquid container is placed in the rinse liquid container accommodating chamber from above. The flushing-liquid container has a flushing-liquid plug valve on its bottom, which is inserted into the flushing-liquid plug valve receptacle and latched in the lower end position of the flushing-liquid container. The flushing liquid line leads from the flushing liquid plug valve receptacle to the flushing liquid inlet of the multi-way valve.

The rinsing liquid container rests against the inner side of the rinsing liquid container receiving space, so that heat is transferred from the peltier element, i.e. the hot side of the peltier element, over a large area to the rinsing liquid container, which is warmed up together with its contents. At the same time, the cold side of the peltier element cools down and the milk container is cooled down together with its contents. If necessary, the milk container can be removed upward from the milk container receiving space and the rinsing liquid container can be removed upward from the rinsing liquid container receiving space.

A multi-way valve having a milk plug valve receptacle serving as a milk inlet, a rinsing liquid inlet, an air inlet connected to an air line, and a multi-way valve outlet is fixedly arranged in a housing base of the housing unit.

The multiplex valve outlet conduit leads from the multiplex valve outlet to a pump configured as a suction pump, which is also fixedly disposed within the housing base. A throttling part is inserted into the outlet conduit of the multi-way valve. The throttle has the function of preparing cold milk foam when the multi-way valve delivers air-mixed milk to the throttle by means of a pump.

The housing base also contains the electric drive of the multi-way valve and of the pump and the internal control unit of the multi-way valve or of the pump, with which the multi-way valve or the pump can be set or switched on.

For supplying the peltier element, the housing base has a supply connection which also supplies the control unit of the drive of the multi-way valve and of the pump. The peltier element is only supplied with current by closing the starting contact by means of the operating element, which in the present example is designed as a tappet, when the cooled milk container is in the lowered state into the end position in the milk container receiving chamber.

The milk which has been precooled in the refrigerator can be additionally cooled in the milk container inserted into the milk container receiving chamber by means of the peltier element, and the rinsing liquid in the rinsing liquid container inserted into the rinsing liquid container receiving chamber can be warmed for good rinsing and cleaning effects.

A discharge conduit is connected to the pressure outlet of the pump within the housing base, the discharge conduit leading to a discharge portion disposed outside the housing base. The outlet part comprises a steam heating device which is connected to a closable steam generator coupling device.

The steam generator coupling means may be coupled with complementary steam generator coupling means of the beverage preparation appliance, which may be loaded with steam from a steam generator within the beverage preparation appliance by a steam conduit through a steam valve.

In the configuration of the device in which no external steam outlet conduit is connected to the steam generator connection and the steam generator connection is closed, the outlet serves as an outlet for cold milk or cold milk foam.

When the steam generator coupling is coupled to a complementary steam generator coupling, opens itself and is connected in a steam-conducting manner with the steam valve open to the steam outlet conduit, the hot steam generated in the steam generator of the beverage preparation appliance can very effectively warm, directly or indirectly, the cold milk foam or the cold milk already prepared in the device, which flows into the outlet provided with the steam heating device. And the steam valve is closed in order to output cold milk foam or cold milk from the discharge.

The steam valve in the steam outlet line and the control units of the multi-way valve and of the pump are expediently controlled by a central control unit of the beverage preparation appliance via control connections, which can be realized by means of wires or wirelessly. For this purpose, the internal control unit of the device can have an interface via which the internal control unit communicates with the external control unit via the control connection.

The multi-way valve, which is also controllable by the central control unit, in the housing base has, in addition to the milk plug valve receptacle or milk inlet, an air inlet with an air line and a rinsing liquid inlet with a rinsing liquid line, which leads to the rinsing liquid plug valve receptacle.

To start the device, the plug valve on the bottom of the milk container is inserted into the milk container receiving space and latched in the milk plug valve receiving space as the milk inlet on the multi-way valve. In addition, the starting contact is connected by means of the actuating element (i.e. by means of the plunger) by means of the inserted milk container.

When the multi-way valve is then set into its first position by its control unit and its drive, the milk inlet or the milk plug valve receptacle is connected to the multi-way valve outlet, wherein the air inlet and the rinsing liquid inlet are closed. The milk sucked in by the pump is sucked out of the multi-way valve outlet and the milk valve passage of the multi-way valve and is delivered to the discharge section as pure milk.

When the multi-way valve is set into the second position by its drive device under the control of its control unit, the milk plug valve receptacle or milk inlet remains connected to the multi-way valve outlet and the air inlet, which is connected to the milk valve channel (also called milk flow path), is open. In addition to the milk sucked in by the pump, air is therefore sucked in and mixed with the milk in the multi-way valve. The resulting milk-air mixture is pumped further by the pump through a throttle arranged between the outlet of the multi-way valve and the discharge, which throttle is arranged upstream of the pump in the present embodiment. The compressed milk-air mixture in the throttle expands downstream of the throttle and the milk foam is conveyed to the outlet via the outlet duct.

In a third position, which is controlled by the control unit and the drive device of the multi-way valve, the milk plug valve receptacle or the milk inlet and the air inlet are closed, while the flushing liquid inlet is open and the flushing liquid line is connected to the multi-way valve outlet via the flushing liquid valve passage. The pump sucks the rinsing liquid through the multi-way valve and conveys it through the multi-way valve outlet conduit, the throttle, the pump and the discharge conduit to the discharge under the following preconditions: the rinsing liquid container is used to initially fill the rinsing liquid container with rinsing liquid, whereby the rinsing liquid plug valve is inserted into the rinsing liquid plug valve receptacle and the rinsing liquid plug valve is latched to the rinsing liquid plug valve receptacle.

In a variant of the device for preparing milk foam, the valve position of the multi-way valve and the operation of the pump can also be selected manually by means of a switching device, not shown, by means of an internal control unit of the multi-way valve and of the pump, independently of the beverage preparation appliance.

The discharge of the device for preparing cold bubbles or delivering cold milk does not need to be connected to an external steam discharge conduit or steam generator. However, for preparing cold bubbles or outputting cold milk, the device may remain connected to the steam outlet conduit if the steam outlet valve is closed by the central control unit or the steam generator is not operating.

In order to prepare hot milk foam or hot milk, the outlet must be functionally coupled to a steam outlet conduit or steam generator by means of its steam generator coupling device, so that in the present example steam is conveyed from the steam outlet conduit into the outlet by means of a controlled steam outlet valve.

The outlet of the device can be coupled with its steam generator coupling alternately to a complementary steam generator coupling of a beverage preparation appliance with a conventional foamer which has a steam generator coupling and a foamer milk conduit and can only output hot milk bubbles.

Foamed milk or milk output made according to one of the above-mentioned alternative methods may be received by a receiving container below the discharge or foamer.

Claims (19)

1. An apparatus for preparing cold and hot selectable milk froths or outputting cold and hot selectable milk, comprising:

a milk container that can be removed from the apparatus;

a milk inlet connecting the milk container via a milk valve passage with a cold frothing device activatable via an air valve passage;

a discharge duct having a discharge portion, disposed downstream of the cold foaming device;

the method is characterized in that:

a milk container can be inserted into the device via a guide and has a milk plug valve on the bottom of the milk container,

a complementary milk plug valve receptacle, which is arranged fixedly in the device, is formed directly on the milk valve channel as a milk inlet, so that the milk plug valve can be inserted into the complementary milk plug valve receptacle and can be latched therein when the milk container is inserted.

2. The apparatus of claim 1, wherein: the device further comprises means for warming the milk froth prepared in the cold frothing apparatus or the milk flowing through the cold frothing apparatus, which can be selectively activated.

3. The apparatus of claim 1, wherein:

the device comprises a housing base on which a milk container receiving chamber is fixedly arranged; and is

The milk container can be inserted into the milk container receiving chamber from above, guided, so that the milk plug valve on the bottom of the milk container engages in the complementary milk plug valve receiving portion and snaps into place therein.

4. The apparatus of claim 3, wherein:

the milk container receiving chamber is connected with the cold side of the Peltier element in a surface heat conduction manner; and is

The milk container rests tightly, but detachably, against the thermally conductive inner side of the milk container receiving space.

5. The apparatus of claim 3, wherein:

a flushing liquid container accommodating chamber is fixedly arranged on the shell base, and the flushing liquid container accommodating chamber is connected with the hot side surface of the Peltier element in a heat conduction way;

the flushing-liquid container with the flushing-liquid plug valve on the bottom can be inserted into the flushing-liquid container receptacle by means of a guide, so that the flushing-liquid plug valve can be inserted into a complementary flushing-liquid plug valve receptacle which is connected in a fluid-conducting manner to the flushing-liquid inlet of the flushing-liquid valve channel.

6. The apparatus of claim 5, wherein: the peltier element is arranged between the milk container receiving space and the rinsing liquid container receiving space in a thermally conductive manner.

7. The apparatus of claim 3, wherein: a multi-way valve is disposed within the housing base, the multi-way valve comprising: a milk valve passage with a complementary milk plug valve receptacle on the milk inlet; an air valve passage; an outlet of the multi-way valve; and a flushing liquid valve passage through which a flushing liquid conduit can be connected to the multi-way valve outlet.

8. The apparatus of claim 7, wherein:

a cold foaming device and a pump are arranged between the outlet of the multi-way valve and the discharge conduit according to the flowing relation in the shell base; and is

An electric drive for the multi-way valve and for the pump is arranged in the housing base.

9. The apparatus of claim 1, wherein: a throttle section is provided as a cold foaming device.

10. The apparatus of claim 1, wherein: the outlet part comprises a steam heating device with a closable steam generator coupling, with which the outlet part is adapted to warm cold milk foam prepared in the cold frothing device or milk flowing out of the cold frothing device.

11. The apparatus of claim 10, wherein: the steam generator coupling device is configured to be automatically shut off in an uncoupled state.

12. The apparatus of claim 10, wherein: the discharge unit includes a mixing device as a steam heating device for mixing the foamed milk or the foamed milk flowing out of the cold foaming device with steam.

13. The apparatus of claim 10, wherein: the discharge unit includes a heat exchanger for heating with steam as a steam heating device.

14. The apparatus of claim 8, wherein: an internal control unit of the electric drive of the multi-way valve and the pump is arranged in the housing base.

15. The apparatus of claim 8, wherein: an electrical supply connection and an actuating contact, which can be actuated by an insertable milk container and by means of which the electrical supply to the peltier element can be activated, are arranged in the housing base.

16. The apparatus of claim 14, wherein: the internal control unit has an interface for wireless or wired connection with the central control unit.

17. A beverage preparation appliance with a steam generator comprising a device for preparing a hot and optionally hot milk foam or a hot and optionally hot milk according to claim 10, characterized in that: the steam generator coupling means of the device can be coupled to a steam outlet conduit of the steam generator, which is provided with a controllable steam valve.

18. The beverage preparation appliance of claim 17, wherein:

the beverage preparation appliance comprising a device for preparing a cold-hot selectable milk foam or a cold-hot selectable milk according to claim 16,

the central control unit is an integral part of the beverage preparation appliance; and is

The operating device of the steam valve is connected with the central control unit.

19. A beverage preparation appliance as claimed in claim 17 or 18 wherein: the beverage preparation appliance is a coffee beverage preparation appliance.