Automatic milk foamer

The invention relates to an automatic milk foamer having a container for receiving milk and a base body on which or in which the container can be placed. The milk foamer also includes a stirring device that can be placed in the container for foaming the milk, a motor provided in the base body for driving the stirring device, and a heating device for warming the milk present in the container. The heating device includes an alternating magnetic field generator provided in the base body for generating an alternating magnetic field. The container is designed such that it heats up due to the alternating magnetic field.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a national stage filing under 35 U.S.C. 371 of International Application No. PCT/EP2008/009358, filed Nov. 6, 2008, which claims foreign priority to German Patent Application No. 102007063549.6, filed Dec. 21, 2007, the disclosures of which are incorporated by reference herein in their entireties. Priority to each application is hereby claimed.

DESCRIPTION

The invention is an automatic milk foamer with a container for the intake of milk, with a base on or in which the container can be placed, with a stirring device to foam the milk that can be inserted in the container. A motor to drive the stirring device can be provided in the base, as well as a heating device to heat any milk present in the container.

Such milk foamers, which are available as portable units, are already known in the current state of the art, for example from WO 2006/050900 A1. The disadvantage of such milk foamers is that especially the cleaning of the container is laborious and time-consuming. For example, if the container is not rinsed immediately after the milk has been foamed, milk residue may dry up in the container and form a crust that can lead to a build-up of bacteria and germs. Since the container features electric and/or electronic components, in particular in the form of the heating unit, it is not possible, for example, to submerge the container in a cleaning solution or to clean it in a dishwasher.

From the EP 1 731 068 A1, a cooking mixer with a container that can be detached from a base is known. Only induction heating was provided to heat the food products present in the container. Similar cooking mixers are known from the JP 2004 261254 A and the WO 2006/124051 A.

SUMMARY OF THE INVENTION

The present invention addresses the problem of providing a milk foamer, as mentioned above, that is easier to handle for the user.

This invention solves this problem with a milk foamer with the characteristics of claim1.

Such a milk foamer has the advantage that the electric or electronic components of the heating unit are not included in or on the container, but are exclusively housed within the base. Due to a suitable material selection of the container it can still be guaranteed, however, that a reliable and rapid heating of the milk present in the container will take place.

The container is thus preferably free of electric or electronic components as well as of electric connections. Such a container has the advantage that it can be submerged in cleaning solution for cleaning purposes or put in a dishwasher.

To achieve a suitable heating effect, parts of the container or the container can be manufactured, at least in part, out of electrically conductive and/or ferromagnetic materials.

It is especially advantageous if the bottom of the container is manufactured, at least in part, out of a ferromagnetic and/or electrically conductive material. In this case, the alternating field generator will be situated in the base in the area in which the bottom of the container rests on the base. Using the alternating field generator, the bottom of the container can then be heated, causing any milk present in the container to be heated. The use of ferromagnetic material has the advantage that a bundling of the magnetic alternating field can be generated in such a way that a rapid heating of the bottom of the container and thus of the milk occurs.

Preferably, the entire bottom of the container should be made of a ferromagnetic plate. The thickness of the bottom in this case needs to be adjusted with respect to the type and intensity of the generated magnetic alternating field.

In an additional advantageous embodiment of the invention, additionally or alternatively it can be provided that the container wall or parts of it are made of a ferromagnetic or electrically conductive material and that the base can have a nest-like depression to receive the container. The base has a wall section essentially running parallel to the wall of the container behind which the alternating field generator is situated. As a consequence of the alternating field, a heating of the wall of the container or a section of the wall is achieved. This has the decisive advantage that construction volume is saved in the area underneath the container. Especially the area of the base below the container can house a range of components, for example an electric motor to power the stirring device. This means that construction volume can be saved through the arrangement of the alternating field generator essentially parallel to the wall of the container. In addition, with this construction design a container with a small footprint and a comparatively great height can be created. The surface of the wall of the container, which is heated due to the magnetic alternating field, can thus be bigger than the surface of the bottom. This means that a better and more even heating of the milk present in the container can be achieved. An additional advantage is that other components present in the base portion, such as in particular an electric motor, can be arranged at a greater distance from the alternating field generator. In this case it is to be taken into account that the alternating field generator emits a magnetic alternating field in all spatial directions. This means that it can indeed occur that electrically conductive components, such as in particular an electric motor housed in the casing, may be subject to an undesirable heating effect if they are arranged close to the alternating field generator. Especially because the alternating field generator is arranged in parallel to the wall of the container in the area of the nest-like depression it can be arranged comparatively far from other electrically conductive components.

In this case, the alternating field generator can be arranged directly on the corresponding wall section of the base or can also be arranged at a distance from this. Depending on the desired intensity of the generated magnetic alternating field, a corresponding calibration is possible.

The alternating field generator can be designed as an induction coil that surrounds the wall section that forms the depression on the base in ring-form at least in part. This guarantees that the wall of the container or, as the case may be, parts thereof is or are evenly heated. The alternating field generator can in this case be realized as a single-layer induction coil.

In addition it is advantageous if the alternating field generator with the container recessed in the depression covers a part of the wall of the container that lies in a range from a quarter to three quarters of the wall of the container. The covered part of the wall of the container is then preferably constructed out of an electrically conductive and/or magnetic material. This provides a sufficiently large surface that is heated due to the magnetic alternating field.

In another embodiment of the invention it is advantageous if the alternating field generator with the container recessed in the depression covers a part of the wall of the container that is greater than the part of the wall of the container that is covered by the milk present in the container when the milk foamer is not in operation and the maximum permissible filling volume of milk is present in the container. If the stirring device is not rotating, then as a result sections of the container wall are also heated that are not in contact with the milk. If, however, the stirring device is switched on, then the milk rises up the wall of the container due to the rotating movement. Milk is then also heated on the part of the container wall that is wetted by the milk when the stirring device is not rotating. On the whole, this results in a comparatively large surface that is heated by the alternating field, which leads to a rapid and even heating of the milk.

In another embodiment of the invention it is provided that those sections of the wall or the bottom of the container that do not serve to heat the milk present in the container are at least in part made out of glass. This makes it possible to observe the milk foam created in the container while it is being made and to check in a very simple way whether the milk foam has a suitable consistency or possibly whether sufficient milk foam was prepared.

In an especially preferred embodiment, the entire bottom of the container and the section of the container wall is connected to the bottom of the container, which can be approximately a quarter to three quarters of the height of the container, made of a single piece of an electrically conductive, and in particular ferromagnetic, material. The remaining container wall stretching up from that point is preferably made out of glass.

According to the invention, alternating field generators can be provided principally in such a way that both the bottom as well as the container wall are heated. This means that as a whole the area of the container that is being heated is comparatively large, which leads to a fast and even heating of the milk.

In accordance with the another embodiment of the invention, the bottom of the container on its underside at least in segments features a coating that acts in a heat-insulating way and due to the magnetic alternating field can not be heated or can be heated only a little. The bottom of the container may also have an insulating plate or correspondingly arranged insulation sections. This has the advantage that the container with the hot milk can be removed from the base and placed on a surface, for example a table, without this being heated or damaged due to the hot content of the container. Still, if the part of the bottom of the container that faces the interior is made out of a material that heats up due to the magnetic alternating field, then the bottom of the container and thus the milk are heated.

To power the stirring device, it is advantageous to provide a motor to drive the stirring device in the base.

The stirring device as such should preferably be arranged in such a way that it can be disconnected from the swivel coupling. This would allow the stirring device to be removed before pouring out the milk foam or to clean the container.

The stirring device is swivel-coupled to the motor via a contact-less magnetic coupling. Such a contact-less magnetic coupling has the advantage that no mechanical components run through the entire container; seals are therefore not required.

To realize the magnetic coupling, a raised part facing axially upwards and in particular at least for the most part shaped in cylindrical form needs to be provided. On the side facing away from the interior of the container, a magnet or as the case may be a ferromagnetic material can then be provided on a shaft that is powered by the motor and juts out into the raised part. On the axially or radially opposite side of the raised part in the interior of the container, ferromagnetic or magnetized sections can be provided for swivel coupling the stirring device. The sections interact with the magnetic or the ferromagnetic material in such a way that when the shaft turns, the stirring device is set into a rotating motion. The raised part in the bottom of the container can thus simultaneously serve to store the stirring device in the container.

In one embodiment, the motor is activated in such a way that it runs with a fluctuating rotational speed. This makes it possible that the milk foam being formed will now and again collapse slightly due to the different rotational speeds of the stirring device, thus achieving a better and more even mixing of the milk. It is possible to provide a random number generator for the activation of the motor.

Additional details and advantageous embodiments of the invention can be found in the following description.

DETAILED DESCRIPTION OF THE DRAWINGS

The milk foamer10presented inFIG. 1comprises a base12as well as a container14that can be placed on the base12to take in milk. The cylindrical wall16of container14is made out of glass. To handle the container14, two metal bands18are provided that encompass the wall16. Between the bands18, a handle21is provided.

As illustrated inFIG. 2, the container14features a bottom20that is made out of a ferromagnetic material and, as shown inFIG. 2, can be double-layered and of a single piece with the lower metal band. The side of the container14facing away from the bottom of the container20is closed with a detachable lid22. The bottom20of the container on its underside features heat-insulating and electric non-conductive isolation sections in the form of a ceramic plate23.

Inside the container14there is a stirring device24that can be taken out of the container14in an axial direction. The stirring device24in this case is arranged along the central longitudinal axis of the container14in a rotatable way in the container14. On the bottom20of the container, a raised part26facing axially upwards is provided in a circular cylindrical way. The raised part26serves as a bearing pin for the stirring device24.

As can be seen inFIG. 2, an electric motor28is provided in the base12to drive a shaft30. The free end of shaft30, which features magnetic or magnet sections32, here juts into the side of the raised part26facing away from the interior of the container. The stirring device24features the ferromagnetic coupling sections34radially opposite to the magnet sections32. These coupling sections are designed in such a way that if the motor shaft30turns with the magnet sections32, the coupling sections34or, as the case may be, the stirring device24for the foaming of the milk present in container14are set in a rotating motion. The motion coupling between the motor28or, as the case may be, the magnet sections32and the stirring device24or, as the case may be, the coupling sections34thus takes place in a contact-less way through the bottom of the container20or, as the case may be, the raised part26of the container14. A concrete possibility of a non-contact motion coupling is described, for example, in WO2006/050900 A1. The electric motor28on its underside features a shaft section42to which a cooling fan44is attached.

In the base12, an alternating field generator36is provided to generate a magnetic alternating field. Here the alternating field is generated in such a way that the ferromagnetic bottom20of the container14heats itself due to the alternating field so that it inductively heats the milk present in the container14. Such an induction heat arrangement has the advantage that all electric and electronic components are situated within the base12, so that neither electric or electronic components nor electric connections need to be provided on the container14. The container14is designed in such a way that it can be taken off the base12and completely submerged in cleaning solution or cleaned in a dishwasher without being damaged. The stirring device24is preferably taken out of the container14for cleaning. It is also conceivable that the glass wall16along with the bottom20of the container and bottom plate23can be taken out of the bands18in an axial direction, so that only the glass wall16along with the bottom20of the container and with the bottom plate23(which can form an inseparable unit) can be cleaned.

By providing the heat-insulating plate23, the interior of the bottom20of the container is heated for the heating of the milk, but the underside or plate23are not heated. This has the advantage that the container16with the hot milk can be removed from the base12and placed on a surface, for example a table, without this being heated or damaged due to the hot content of the container16.

In the base12, a conductor plate38is provided that serves to drive the motor28and the alternating field generator36. To start up the milk foamer10, a start button40has been provided at the front of the base12, as can be clearly seen inFIG. 1. Pushing the start button40results in the activation of the electric motor28(and thus of stirring device24) and of the alternating field generator36(and thus the heating of bottom20) in such a way that the milk present in the container14is heated and foamed.

The driving of motor28here preferably takes place using a random number generator so that a fluctuating rotational speed of the motor and thus of the stirring devices24can be achieved. This allows for a better mixing of the foaming milk.

FIGS. 3 and 4show a second invention of a milk foamer50in which components of this milk foamer50are provided with reference numbers that correspond to the reference numbers of the components of the milk foamer10in accordance withFIGS. 1 and 2.

As can be seen inFIG. 3, the base12of the milk foamer50features a nest-like depression52to receive the container14. The depression52is surrounded in a radial direction by a ring-shaped wall section54that essentially runs parallel to the wall of the container16. The side of the wall section54facing away from the container14also features a ring-shaped circumferential alternating field generator36. The alternating field generator36here comprises a single-layered induction coil56.

Unlike the milk foamer10according toFIGS. 1 and 2, in the milk foamer50according toFIGS. 3 and 4the alternating field generator36is not situated in the area of the bottom20of the container14, but in the area of the wall16. The alternating field generator36here covers approximately a third of the height of the wall16of the container14, as can be seen in particular inFIG. 4.

To heat the container16, the design according toFIGS. 3 and 4consists completely of an electrically conductive material that also has ferromagnetic properties. According to the present invention, it is still conceivable that the upper section of the container14or its wall16which is not situated opposite the alternating field generator36can be made out of glass. This makes it possible to observe the milk present in the container14during the foaming process.

The ring-shaped arrangement of the alternating field generator36according toFIG. 4has the advantage that the alternating field generator36is further away from the electric motor28than is the case with milk foamer10according toFIGS. 1 and 2. This results in the undesirable heating of the electric motor28due to the present alternating field being less of a problem than it is with milk foamer10according toFIGS. 1 and 2, since the alternating field generator there is situated closer to the electric motor28. In addition, the milk foamer50can heat a larger surface of the container14than is the case with milk foamer10, in which the surface to be heated is limited to the ground surface of the bottom of the container20.

On the whole, milk foamer50can thus induce heat into the container14in a more even way, which in turn can prevent any undesirable burning of milk in the container14.

The container14can, as indicated inFIG. 4, feature a maximum fill level58. To ensure that the container14does not overflow during the foaming process, milk may only be filled up to this level58in the container. As can be seen inFIG. 4, the alternating field generator36covers a part of the wall of the container16that is greater than the part of the wall of the container16that is covered by milk filled up to the level58. This makes it possible for the milk that rises up along the wall16during the foaming process to also be heated. On the whole this results in the surface being impacted by the magnetic field being increased.

As can be seen inFIG. 4, the alternating field generator36along with the induction coil56can be arranged on a shared support base60which is arranged along the wall of the base12which forms the bottom64of the depression52via connecting sections62. When the container14is placed into the depression53, the bottom64of the depression52features a raised part66with a sidewall68and an upper wall70completely covering the shaft30. The raised part66extends into the raised part26of the container14. The magnet sections32juts into this raised part66.