Patent Description:
Many well-known devices use steam to heat and to foam milk, while other systems use mechanical steam-coupled stirrers to incorporate air into the milk or electrical resistors to heat the milk.

Other Venturi-effect systems suck milk, froth it and heat it directly in the milk container.

None of the existing solutions provides for an easy-to-clean system as milk-wetted components are sometimes difficult to access on all their inner surfaces.

Some existing solutions are particularly inconvenient because they require the frothed milk to be transferred by hand from the milk container to the cup.

In addition, many known devices typically offer the possibility to automatically dispense only a limited range of products in terms of milk quantity, cream grade and temperature of the frothed milk.

Some existing systems allow to expand the range of products dispensed through specific manual operations, but the result is entrusted to personal skill.

<CIT> discloses a device for milk frothing, <CIT> discloses a device for dispensing milk and/o milk froth from a container, <CIT> relates to an automatic milk foamer.

The technical task of the present invention is, therefore, to realise a milk frothing device and a coffee machine which obviate the technical drawbacks described above of the prior art.

Within the context of this technical task an aim of the invention is to realise a milk frothing device and a coffee machine that allow dispensing a wide range of products in terms of the quantity of milk dispensed, cream degree and temperature of the frothed milk.

A further aim of the invention is to realise a milk frothing device that is easy to inspect and clean in all its components.

Last but not least, the aim of the invention is to realise a milk frothing device that is extremely convenient to use.

The technical task, as well as these and other purposes, according to the present invention are achieved by realising a milk frothing device, characterised in that it comprises a milk container having at least one bottom, a removable lid for the hermetic closure of the milk container, a support base for supporting the milk container, a conduit for dispensing the frothed milk comprising a portion internal to the container which extends towards said bottom of the container and a portion external to said container having a downward dispensing end for the direct dispensing into a cup, a conduit for the inlet of air into the container, a supplier of compressed air to the air inlet conduit for the ejection of the frothed milk contained in said container through said dispensing conduit, a rotatable mechanical stirrer positioned inside said container, a milk heater, and a means for the activation in rotation of said stirrer housed in said support base.

Advantageously, the frothed milk dispensing conduit has an inner diameter comprised between <NUM> and <NUM> so that the milk cream produced can be dispensed without deteriorating during the passage through the frothed milk dispensing conduit itself.

Advantageously, the invention also discloses a coffee machine having such a milk frothing device.

Advantageously, the support base is positioned in front of a front outer wall of said machine provided with a milk temperature sensor present in the container, a pneumatic connector for connecting said air inlet conduit to said air supplier, and an electrical connection means for connecting said means for the activation in rotation to an electric power supply housed inside said coffee machine.

Advantageously, the coffee machine has a user interface for selecting at least a quantity of dispensed frothed milk, a type of milk and a degree of frothing, a data archive that supplies for the quantity of dispensed frothed milk selected a first association between type of milk and rotation speed of the mechanical stirrer, and a second association between the degree of frothing and the activation time of the mechanical stirrer, and an electronic controller programmed to acquire a selection of at least a quantity of frothed milk dispensed, a type of milk and a degree of frothing and to control the dispensing of a quantity of frothed milk selected by activating said mechanical stirrer with the rotation speed associated with the type of milk selected and for the time associated with the selected degree of frothing.

Advantageously, said electronic controller is programmed to acquire a selection of a temperature of the quantity of frothed milk dispensed, and to control the dispensing of the quantity of frothed milk selected through the activation of said heater until reporting that the temperature selected has been reached by said temperature sensor.

Other features of the present invention are further defined in the following claims.

Further features and advantages of the invention will more fully emerge from the description of a preferred but not exclusive embodiment of the milk frothing device according to the invention, illustrated by way of non-limiting example in the appended drawings, in which:.

Equivalent parts in the following description will be indicated with the same numerical references.

With reference to the aforementioned figures, a milk frothing device indicated as a whole with reference numeral <NUM> is shown.

The milk frothing device <NUM> comprises a support base <NUM> and a milk container <NUM> which is positionable on the support base <NUM>.

The bottom <NUM> of the milk container <NUM> illustrated in <FIG>, for reasons that will be clearer below, is made of non-magnetic thermoconductive metal, for example a stainless steel or aluminium.

The upper mouth of the milk container <NUM> is hermetically closed by a removable lid <NUM>.

The milk frothing device <NUM> further comprises a conduit <NUM> for dispensing the frothed milk comprising a portion 6a internal to the milk container <NUM> which extends towards the bottom <NUM> of the milk container <NUM> and a portion 6b external to the milk container <NUM> having a downward dispensing end 6c for the direct dispensing into a cup <NUM>.

The milk frothing device <NUM> further comprises a milk temperature sensor <NUM>, for example an infrared non-contact sensor.

The milk frothing device <NUM> further comprises a conduit <NUM> for the inlet of air into the milk container <NUM> and a supplier <NUM> of compressed air to the air inlet conduit <NUM> for the ejection of the frothed milk contained in the milk container <NUM> through the dispensing conduit <NUM>.

The milk frothing device <NUM> further comprises a rotatable mechanical stirrer <NUM> positioned inside the milk container <NUM> for frothing the milk.

The milk frothing device <NUM> further comprises a milk heater <NUM> and a means <NUM> for the activation in rotation of the mechanical stirrer <NUM> housed in the support base <NUM>.

The milk frothing device <NUM> is at least partially made disconnectable from a coffee machine <NUM>.

In the solution illustrated in <FIG>, the heater comprises an electric heater <NUM> housed in the support base <NUM>.

In the solution illustrated in <FIG>, instead, the heater comprises a steam generator <NUM> supplied by a water pump <NUM> and supplying a supply conduit <NUM> of the milk container <NUM>. In addition, the steam generator <NUM> and relative supply pump <NUM> are housed in the frame of the coffee machine, while the supply conduit <NUM> of the milk container <NUM> has a first portion 111a integrated into the coffee machine <NUM> and a second portion 111b integrated into the lid <NUM> and has, especially at the front outer wall <NUM> of the coffee machine <NUM>, a special disconnectable connection means <NUM> between the two portions 111a, 111b.

The coffee machine <NUM> has a user interface.

The user interface can be formed by a dashboard positioned on the front outer wall <NUM> of the coffee machine <NUM>, and include for example a display <NUM> and selectors <NUM>, for example keys and/or knobs.

The user interface, in addition to or as an alternative to the physical dashboard, may include a data transceiver unit for wireless network, for example a short or long range radio frequency transceiver, adapted to interact with electronic devices of a known type, for example smartphones, provided with a special application for interfacing with the coffee machine <NUM>.

The coffee machine <NUM> comprises an electronic controller <NUM>, a hydraulic circuit (not shown) for the production of hot water under pressure provided with a pump and a boiler, a brewing unit (not shown) supplied by the hydraulic circuit and connected to an outer coffee dispenser <NUM> mounted on the front outer wall <NUM>.

Other components housed within the frame of the coffee machine <NUM> may be provided, for example a steam production circuit (shown for example in <FIG>), a grinder (not shown) supplied by a coffee bean loading hopper <NUM>.

The temperature sensor <NUM> is permanently fixed externally to the front outer wall <NUM> of the coffee machine <NUM>.

The air supplier <NUM>, comprising for example an air pump 9a, is permanently housed within the frame of the coffee machine <NUM>.

Preferably, the support base <NUM> is instead disconnectable from the front outer wall <NUM> of the coffee machine.

In particular, the support base <NUM> is positioned at the base of the coffee machine <NUM> in front of the front outer wall <NUM> of the coffee machine <NUM>.

The front outer wall <NUM> of the coffee machine <NUM> supports, in addition to the temperature sensor <NUM>, a pneumatic connector <NUM> for disconnectable connection of the air inlet conduit <NUM> to the air supplier <NUM> and an electrical connection means <NUM> for disconnectable connection of the means <NUM> for the activation in rotation to an electric power supply (not shown) housed in the frame of the coffee machine <NUM>.

The lid <NUM> is removable from the milk container <NUM> together with the frothed milk dispensing conduit <NUM> and the mechanical stirrer <NUM>.

The lid <NUM> supports the frothed milk dispensing conduit <NUM> and the inner portion 6a of the frothed milk dispensing conduit <NUM> in turn supports the mechanical stirrer <NUM> externally in free rotation on itself.

The frothed milk dispensing conduit <NUM> can be fixed to the lid <NUM> or be formed as a single piece with the lid <NUM>.

The inner portion 6a of the frothed milk dispensing conduit <NUM> advantageously acts as a rotation pivot for the mechanical stirrer <NUM>.

The mechanical stirrer <NUM> has an annular central body 10a and having an inner cylindrical surface conjugated to an outer cylindrical surface of the frothed milk dispensing conduit <NUM>.

The annular central body 10a supports, on its outer perimeter, one or more mechanical stirring elements, for example a series of radial blades or a spiral toroidal whip 10b.

At the lower end the inner portion 6a of the frothed milk dispensing conduit <NUM> has an outer perimeter flange 6d supporting the mechanical stirrer <NUM>.

At least the lower end portion of the inner portion 6a of the frothed milk dispensing conduit <NUM> may be deformable, for example by crushing, to allow the mechanical stirrer <NUM> to be hooked and unhooked.

The inner portion 6a of the frothed milk dispensing conduit <NUM> extends vertically to provide a vertical axis of rotation to the mechanical stirrer <NUM>.

Preferably the lid <NUM> is removable from the milk container <NUM> together with the air inlet conduit <NUM>.

The air inlet conduit <NUM> can also be fixed or obtained as a single piece with the lid <NUM>.

The milk frothing device <NUM> includes the magnetic transmission means for transmitting the movement from the activation means <NUM> to the mechanical stirrer <NUM>.

The activation means <NUM> comprises a wheel <NUM> coaxial to the mechanical stirrer <NUM> and housed in the support base <NUM>, and a drive motor <NUM> for driving the wheel <NUM> also housed in the support base <NUM>.

The magnetic transmission means may include permanent magnet blocks <NUM> fixed along a circumference of the wheel <NUM>, and ferromagnetic blocks <NUM> fixed along a circumference of same diameter as the mechanical stirrer <NUM>.

The permanent magnet blocks <NUM> in rotation interact magnetically and drag into rotation the ferromagnetic blocks <NUM> and consequently the mechanical stirrer <NUM>.

To optimize the dragging force, it is convenient to position the wheel <NUM> as close as possible to the bottom <NUM> of the milk container <NUM>.

The milk frothing device <NUM> also comprises a conduit <NUM> for connecting the air inlet conduit <NUM> to the atmospheric environment external to the milk container <NUM>, and valve means <NUM>, for example a solenoid valve, for the opening and closing of the connection conduit <NUM>.

The connection conduit <NUM>, as we will see, remains open when the mechanical stirrer <NUM> is in operation to prevent the accidental escape of the milk cream through the dispensing conduit <NUM> before the milk is fully frothed.

It should be noted that the frothed milk dispensing conduit <NUM> has an inner diameter comprised between <NUM> and <NUM> and there are no construction obstructions to ensure that the milk cream produced does not deteriorate when it is dispensed.

The milk container <NUM> can be rested on an area of the support base <NUM> centred above the wheel <NUM>.

The support area of the milk container <NUM> is located in a laterally staggered position from the external coffee dispenser <NUM>.

The temperature sensor <NUM> and the pneumatic connector <NUM> are positioned at a height above the support area of the milk container <NUM> and the electrical connection means <NUM> is positioned on the rear side of the support base <NUM>.

The user interface of the coffee machine <NUM> has at least one selector <NUM> of a quantity of dispensed frothed milk, at least one selector <NUM> of a type of milk, at least one selector <NUM> of a degree of frothing.

The electronic controller <NUM> is connected, in addition to all the active components of the milk frothing device <NUM>, also to a data archive that supplies for the quantity of dispensed frothed milk selected a first association between type of milk and rotation speed of the mechanical stirrer <NUM>, and a second association between degree of frothing and activation time of the mechanical stirrer <NUM>.

The electronic controller <NUM> is programmed to acquire through the user interface a selection of at least a quantity of dispensed frothed milk, a type of milk and a degree of frothing and to control the dispensing of the selected quantity of frothed milk by activation of the mechanical stirrer <NUM> with the rotation speed associated with the selected type of milk and for the time associated with the selected degree of frothing.

In addition, the electronic controller <NUM> is programmed to acquire, again via the user interface, a selection of a temperature of the quantity of frothed milk dispensed, and to control the activation of the heater until reporting that the selected temperature has been reached by the temperature sensor <NUM>.

Below is a table illustrating an example of a range of products that can be dispensed and selected on request through the user interface.

The coffee machine <NUM> allows the automatic dispensing of the recipes into the cup, and allows to reach very low dispensing temperatures, for example of <NUM> or very high, for example above <NUM>.

The controller <NUM> advantageously associates the ideal rotation speed, indicated in the data archive, with the selected type of milk.

It is known that the types of milk differ in the content of fats and proteins and other surfactants that affect the formation of the milk cream.

Today, non-dairy milk is also often used and this variety of choice requires greater versatility in adapting the milk cream formation cycle.

For example, whole milk having a higher fat and protein content can be foamed by mechanical stirring at <NUM> rpm, skimmed milk can be foamed by mechanical stirring at <NUM> rpm, vegetable milk, depending on the type, can be foamed by mechanical stirring from <NUM> to <NUM> rpm.

The milk frothing device <NUM> can also be used to dispense milk with special additives and flavourings, such as vanilla or chocolate or strawberry in powder or liquid, added directly into the milk container <NUM>.

The user selects the type of milk, quantity, cream degree and temperature of the milk dispensed through the user interface.

The electronic controller <NUM> obtains from the archive the process execution data for the quantity of dispensed milk selected, in terms of speed of the mechanical stirrer <NUM>, duration of activation of the mechanical stirrer <NUM>, duration of activation of the air pump 9a, while the duration of activation of the heater is defined by the temperature sensor <NUM> which reports that the selected temperature has been reached.

Reference is now made to the operation of the device illustrated in <FIG>.

Before starting the dispensing cycle, the user electrically connects the support base <NUM> to the electrical connection means <NUM>, for example by means of electrical plugs of the support base <NUM> that engage in electrical sockets of the electrical connection means <NUM>.

In this case, the support base also makes the electrical connection of electrical connection means <NUM> of the electrical heater <NUM> to the electric power supply internal to the coffee machine.

The user then places the milk container <NUM> on the support base <NUM> above the electric heater <NUM> and connects the air conduit <NUM> to the compressed air supplier <NUM>.

At this point, the user, via the user interface, controls the start of the dispensing cycle.

The cycle starts with the air solenoid valve <NUM> open and the air pump 9a deactivated.

The controller <NUM> controls the activation of the mechanical stirrer <NUM> at the rotation speed indicated in the data archive and for the duration indicated in the data archive.

If the user selects a milk that is also hot as well as foamed, the controller also controls the activation of the electric heater <NUM>.

At the end of the foaming and upon reaching the selected temperature, the controller <NUM> controls the deactivation of the mechanical stirrer <NUM> and respectively of the electric heater <NUM>, and controls the closure of the air solenoid valve <NUM>.

At this point, the electronic controller <NUM> controls the closure of the air solenoid valve <NUM> and the activation of the air pump 9a with a duration also indicated in the data archive that preferably also supplies for the quantity of dispensed frothed milk selected a third association between the type of milk and the activation time of the air pump 9a.

With the air solenoid valve <NUM> closed, the milk container <NUM> is pressurized by the air pump 9a and the milk foam is forced out of the dispensing conduit <NUM> towards the cup <NUM>.

The compressed air of only <NUM>-<NUM> bar in combination with a dispensing conduit <NUM> with high inner diameter, allows the dispensing directly into the cup <NUM> without deteriorating the quality of the milk foam as it passes through the dispensing conduit <NUM>.

It is also possible to exclude the control of the dispensing cycle based on the data present in the data archive and proceed to a custom selection of the parameters of the dispensing cycle.

Claim 1:
A milk frothing device (<NUM>), comprising a milk container (<NUM>) having at least one bottom (<NUM>), a support base (<NUM>) for supporting the milk container (<NUM>), a conduit (<NUM>) for dispensing the frothed milk comprising a portion (6a) internal to the milk container (<NUM>) which extends towards said bottom (<NUM>) of the milk container (<NUM>) and a portion (6b) external to said milk container (<NUM>) having a downward dispensing end (6c) for the direct dispensing into a cup (<NUM>), a conduit (<NUM>) for the inlet of air into the milk container (<NUM>), a rotatable mechanical stirrer (<NUM>) positioned inside said milk container (<NUM>) for frothing the milk, a milk heater, and a means (<NUM>) for the activation in rotation of said mechanical stirrer (<NUM>) housed in said support base (<NUM>), characterized in that it comprises a removable lid (<NUM>) for the hermetic closure of said milk container (<NUM>), and a supplier (<NUM>) of compressed air to said air inlet conduit (<NUM>) for the ejection of the frothed milk contained in said milk container (<NUM>) through said dispensing conduit (<NUM>).