The present invention relates to a so-called "milk frother" apparatus, that is to say an apparatus for preparing a foam from a liquid, in particular from a food liquid, such as milk or a milk-based liquid.

An apparatus of this type typically comprises a support base provided with electrical supply means, a vessel for containing an amount of liquid, a heating element for heating the liquid contained in the vessel during the preparation of the foam, a stirring member arranged to be removably mounted in the vessel to rotate about an axis of rotation, electrically operated driving means (typically an electric motor) for driving the stirring member to rotate about the aforementioned axis of rotation in order to agitate the liquid contained in the vessel and thus making the foam, and user interface means for enabling the user to control the apparatus.

A milk frother apparatus is typically available in two different configurations, namely a configuration with an integrated vessel and a configuration with a separate vessel. According to the first known configuration (integrated vessel), all the components of the apparatus, with the exception of the support base, form a single unit. In this case, therefore, the apparatus comprises a support base and an upper unit which is arranged to be placed on the support base and comprises both a vessel and a heating element electrically powered by the support base when the upper unit is mounted on the support base. Such a configuration allows a good heat exchange between the vessel and the heating element, but makes it difficult to wash the vessel, whether under running water or in a dishwashing machine, due to the presence of electrical contacts in the upper unit.

According to the other known configuration (separate vessel), the vessel is a component distinct from the rest of the apparatus, in particular distinct from the electrical/electronic part of the apparatus. In the operating condition, the vessel rests on a base unit comprising the support base, the heating element, the electric motor and the user interface. The user may however separate the vessel from the base unit, for example, to pour out the obtained foam or to wash the vessel. Such a configuration makes it particularly easy to wash the vessel, as the vessel may be separated from the rest of the apparatus. On the other hand, the heat exchange between the vessel and the heating element is not as good as the configuration with an integrated vessel, since the vessel is no longer in direct contact with the heating element.

A milk frother apparatus according to the preamble of independent claim 1 is known from EP 2 526 844 Al .

It is an object of the present invention to provide an apparatus for preparing a foam from a liquid, particularly a food liquid, such as milk or a milk-based liquid, which allows the advantages of the two known configurations described above to be combined, i.e. which ensures a high heat exchange between the vessel and the heating element and at the same time allows the vessel to be separated from the electrical/electronic part of the apparatus, for example to allow the vessel to be washed in a dishwashing machine.

This and other objects are fully achieved according to the present invention by virtue of an apparatus having the features specified in independent claim 1. Advantageous embodiments of the invention form the subject-matter of the dependent claims.

In short, the invention is based on the idea of making the apparatus in three main parts which may be separated from one another, namely

an upper body acting as a vessel for containing an amount of liquid to be frothed, an intermediate body provided with heating means and electrically operated driving means for driving a stirrer arranged inside the vessel to rotate, and

a base body provided with electrical connection means for connection to a power supply and for connection to the intermediate body,

wherein the upper body includes a cylindrical shaped main portion, open at its top, and a coupling portion, also having a cylindrical shape, which is placed underneath the main portion and communicates therewith,

wherein the intemiediate body is configured to be supported, in an operating condition of the apparatus, on the base body so as to be electrically connected to the base body by the aforesaid electrical connection means and to be separable from the base body,

wherein the intermediate body has on its top a seat for receiving the coupling portion of the upper body,

wherein the upper body and the intermediate body are provided with releasable coupling means for coupling the vessel to the intermediate body when the coupling portion of the upper body is inserted into the relative seat provided in the intermediate body, and wherein the aforesaid heating means are arranged around the seat provided in the intermediate body.

By virtue of the fact that the upper body is separable from the rest of the apparatus, in particular from the electrical/electronic part of the apparatus, washing the vessel in a dishwashing machine is easier. Moreover, by virtue of the fact that the upper body and the intermediate body are coupled with one another by inserting a coupling portion of the upper body into a respective seat of the intermediate body and that the heating means are arranged around that seat, the contact surface between these two components of the apparatus is increased with respect to the case of simple contact of the upper body on the base of the apparatus (as in the known solution of the apparatus with separate vessel), and consequently the heat exchange between the heating means and the upper body is increased. An apparatus according to the invention thus succeeds in combining the advantages of the two known configurations mentioned above.

Preferably, the coupling means are threaded coupling means including an external thread provided on the coupling portion of the upper body and a mating internal thread provided in the seat of the intermediate body.

According to an embodiment, the heating means include an electrical resistor having a spiral shape that follows the internal thread of the seat provided in the intermediate body. Further features and advantages of the present invention will become more evident from the following detailed description, given purely by way of non-limiting example with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of an apparatus for preparing a foam from a liquid, particularly from a food liquid, such as milk or a milk-based liquid, according to an embodiment of the present invention;

Figure 2 is a perspective view of the apparatus of Figure 1 , with the three main parts of the apparatus separated from one another;

Figure 3 shows a cutaway view of the apparatus of Figure 1 , in the coupling area between the upper body and the intermediate body; and

Figure 4 is an axial sectional view of the apparatus of Figure 1 , which shows on an enlarged scale the coupling area between the upper body and the intermediate body.

With reference to the drawings, an apparatus according to the invention, to be used for preparing a foam from a food liquid, such as milk or a milk-based liquid, for the preparation of drinks, such as cappuccino, latte macchiato, hot chocolate, etc. is generally indicated at 10.

The apparatus 10 basically comprises the following three main parts: an upper body 12 acting as a vessel (hereinafter referred to as "vessel 12") arranged to contain an amount of food liquid to be frothed, an intermediate body 14 and a base body 16. The vessel 12 includes a cylindrical-shaped main portion 18, open at its top, and a coupling portion 20, also having a cylindrical shape, which is placed underneath the main portion 18 and communicates therewith.

The vessel 12 may be provided, at an upper edge of the main portion 18, with a pouring spout (not present in the embodiment shown in the drawings). The vessel 12 may also be conveniently provided with a handle, as well as a removable lid for closing the upper opening tightly. Neither the handle nor the lid are, for the sake of simplicity, shown in the drawings. Preferably, the vessel 12 is made of a material permeable to the magnetic field.

As shown in Figures 3 and 4. inside the vessel 12, and more specifically on a bottom wall 22 of the coupling portion 20, a stirring member, generally indicated at 24, is removably mounted. In the embodiment proposed herein, the stirring member 24 has an overall annular configuration and is preferably mounted around a pin-like portion 26 placed in the center of the bottom wall 22 of the coupling portion 20 and projecting upwards from that wall. The stirring member 24 is able to rotate about an axis of rotation z. In the embodiment illustrated in the drawings, the axis of rotation z is defined by the pin-like portion 26 and coincides with the axis of symmetry of the vessel 12. In the operating condition of the apparatus, the axis of rotation z extends in an essentially vertical direction. The stirring member 24 is of a type known per se. Preferably, the stirring member 24 comprises a radially outer annular element 28, which is provided with permanent magnets and essentially acts as a permanent magnet rotor of an electric motor. The stirring member 24 further comprises stirring means which in the illustrated embodiment comprise a spiral 30 of metal or plastic wire, which is closed in a circular ring, is arranged inside the annular element 28 and is fixed to that element. The stirring member 24 may, however, be provided with stirring means having other shapes/configurations, for example fins, vanes, filamentary appendages, etc., which do not necessarily extend inside the annular element 28. The intermediate body 14 is a cylindrical body preferably having an outer diameter substantially coinciding with the outer diameter of the main portion 18 of the vessel 12. The intermediate body 14 has a substantially flat bottom wall 32. The intermediate body 14 has at its top a cylindrical seat 34 arranged to receive the coupling portion 20 of the vessel 12. The seat 34 is defined by a cylindrical side wall 34a arranged coaxially to, and inside, a side wall 14a of the intermediate body 14, as well as by a substantially flat bottom wall 34b.

The vessel 12 and the intermediate body 14 are provided with releasable coupling means arranged to allow these two main parts of the apparatus 10 to be coupled in a releasable manner when the coupling portion of the vessel 12 is inserted into the seat 34 of the intermediate body 14. By virtue of these releasable coupling means, the vessel 12 and the intermediate body 14 are normally coupled with one another to form a single body. If necessary, for example when the vessel 12 is to be washed, the vessel 12 may be easily separated from the intermediate body. According to an embodiment, these coupling means are threaded coupling means and comprise an external thread 36 provided on the coupling portion 20 of the vessel 12, and more specifically on a cylindrical lateral wall 20a of that portion, and a mating internal thread 38 provided in the seat 34 of the intermediate body 14, and more specifically on the cylindrical side wall 34a of the seat 34.

Inside the intermediate body 14 there is provided a heating element 40, formed for example by an electrical resistor, for heating the vessel and therefore the liquid contained therein. The heating element 40 is arranged around the seat 34, in the vicinity of, or in contact with, the side wall 34a. Preferably, the heating element 40 is further arranged in the vicinity of, or in contact with, the bottom wall 34b. According to the illustrated embodiment, the heating element 40 has a spiral shape which follows the inner thread 38 of the seat 34.

The intermediate body 14 further houses electrically operated driving means for driving the stirring member 24 to rotate about the axis of rotation z. In the illustrated embodiment, these driving means comprise an electric motor 42 arranged to drive a drive shaft 44 to rotate about the axis of rotation z and a magnetic structure 46 fixed to the drive shaft 44 so as to rotate therewith about the axis of rotation z. The magnetic structure 46 may be magnetically coupled with the stirring member 24 through the bottom wall 34b of the seat 34 of the intermediate body 14 and through the bottom wall 22 of the coupling portion 20 of the vessel 12. Preferably, the magnetic structure 46 is received in a special slot 48 provided on the lower face of the bottom wall 34b of the seat 34. In this way, the magnetic structure 46 is made to rotate by the electric motor 42 about the axis of rotation z and generates a rotating magnetic field which, interacting with the permanent magnets of the stirring member 24, induces a rotation of that member about the axis of rotation z.

The base body 16 is provided with user interface means for enabling the user to control the apparatus. In the illustrated embodiment (see in particular Figures 1 and 2), such user interface means comprise a pair of buttons 50 operable by the user. Such user interface means might alternatively include a different number of buttons and/or a screen (such as for example a touchscreen). According to a variant embodiment of the invention (not shown), the interface means are provided on the intermediate body 14, rather than on the base body 16.

The base body 16 is also provided, in a manner known per se, with an electric cable 52 which is connectable to a power supply, as well as with electrical connection means (for example a connecting pin 54) for the electrical connection of the base body 16 with the intermediate body 14, so as to allow the heating element 40 and the electric motor 42 contained in the intermediate body 14 to be powered.

As is evident from the description provided above, an apparatus according to the invention allows to combine the advantage of a high heat exchange between the heating element and the liquid contained in the vessel, by virtue of the fact that the vessel is inserted with its coupling portion into the seat of the intermediate body around which the heating element is arranged, with the advantage of a vessel that is easy to wash, by virtue of the fact that the vessel may be separated from the intermediate body, and therefore from the electrical/electronic part of the device.

Naturally, the principle of the invention remaining unchanged, the embodiments and the constructional details may vary widely with respect to those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the appended claims.