Patent Description:
To date, coffee machines are known that have emulsifying devices for emulsifying milk equipped with a mixing chamber where a flow of steam generates, by Venturi effect, a vacuum, which draws the air needed to emulsify the milk from a specific air supply line.

In some known emulsifying devices for emulsifying milk such as cappuccino makers, the mixing chamber is immersed in a milk container where the milk is emulsified directly.

In other emulsifying devices, a milk container is provided that has a milk supply line in communication with the mixing chamber. In this case, the milk is also sucked by Venturi effect into the mixing chamber, where it is emulsified and then dispensed externally. In both types of emulsifying device, the degree of milk froth is selected by modifying the proportions between the flow of air and the flow of steam. By increasing the quantity of air in the mixture, it is possible to obtain a greater quantity of foam.

In general, the improved emulsion results are obtained by using full fat or partially skimmed cow's milk and supplying the milk at a temperature between <NUM> and <NUM>.

Nevertheless, the use has spread of vegetable beverages that are commonly called "milk" that have physical and chemical features that are completely different from cow's milk and thus require different emulsifying parameters. In particular, these vegetable beverages have boiling points and denaturing points of proteins that are different from the boiling and denaturing points of cow's milk and can thus rise excessively in temperature during the emulsion operation, causing squirts that may potentially injure the user, spoiling the foam, with consequent reduction of the quality of the dispensed product. Further, owing to the cheapness of long-life milk, which is normally kept at ambient temperature, there are many cases of use in which the machine is not regularly provided with milk at low temperature before the emulsion operation.

There is thus a need to provide an emulsion system for all types of milk (animal or vegetable) that enables high quality foam to be obtained without depending on the ability of the user or on the initial temperature of the milk.

<CIT> Al discloses an apparatus for heating and frothing a beverage product, <CIT> Al shows a emulsifying device for emulsifying milk and a coffee machine comprising said emulsifying device for emulsifying milk.

The technical task of the present invention is therefore to realize an emulsifying device for emulsifying milk that makes it possible to eliminate the decried technical drawbacks of the prior art.

Within the scope of this technical task, one object of the invention is to realize a coffee machine comprising an emulsifying device for emulsifying milk that makes it possible to accurately adjust the temperature during the operation of emulsifying the milk regardless of the skills of the user and of the type of milk used.

Another object of the invention is to realize a coffee machine comprising an emulsifying device for emulsifying milk that enables precise adjustment of the froth of the milk, while proving to be simple in construction and low in cost.

A further object of the invention is to provide an emulsifying method for emulsifying a milk using the device of the invention.

The technical task and these and other objects according to the present invention are achieved by realizing a coffee machine comprising an emulsifying device for emulsifying milk, comprising a Venturi mixing chamber, a circuit for supplying air and having an air outlet connected to the mixing chamber, and a circuit for supplying steam having a steam outlet connected to the mixing chamber, wherein said circuit for supplying air comprises at least one first air inlet line equipped with a first shut-off solenoid valve wherein the device comprises a temperature sensor of the emulsified milk and an energy and data exchange means for the sensor, wherein it further comprises an internal controller programmed to perform the following steps:.

According to the invention, a method for emulsifying milk according to claim <NUM> is also provided.

Preferred embodiments of the invention are disclosed in the appended claims. Further characteristics and advantages of the invention will more fully emerge from the description of a preferred but not exclusive embodiment of the emulsifying device for emulsifying milk according to the invention, illustrated by way of non-limiting example in the accompanying figures of the drawings, in which:.

With reference to the figures mentioned, an emulsifying device for emulsifying milk is shown indicated overall with the reference number <NUM>.

The emulsifying device <NUM> is connectable in the manner that will be seen to a coffee machine <NUM>.

The coffee machine <NUM> comprises a controller <NUM>, a control panel (not shown) provided with an ON button and selection buttons of the dispensing cycle, suitable steam generating means (not shown), suitable water heating means (not shown), and an infusion unit (not shown) connected to the water heating means and to an outer coffee dispenser (not shown).

The aforesaid components of the coffee machine <NUM> are housed in an outer frame <NUM> of the coffee machine <NUM>.

The emulsifying device <NUM> comprises a Venturi effect mixing chamber <NUM>, a circuit <NUM> for supplying air having an air outlet <NUM> connected to the mixing chamber, and a circuit <NUM> for supplying steam having a steam outlet <NUM> connected to the mixing chamber <NUM>.

The emulsifying device <NUM> further comprises a temperature sensor <NUM> of the emulsified milk and energy and data exchange means <NUM> for the sensor <NUM>. Advantageously, the circuit <NUM> for supplying air has a first air inlet line <NUM> provided with a first shut-off solenoid valve <NUM>, and optionally at least one second air inlet line <NUM> provided with a second shut-off solenoid valve <NUM>.

In particular, the circuit <NUM> for supplying air also has a third air inlet line <NUM> provided with a third shut-off solenoid valve <NUM>.

The circuit <NUM> for supplying air further comprises a manifold <NUM> into which the air inlet lines <NUM>, <NUM>, and <NUM> enter.

Preferably, the second air inlet line <NUM> has a minimum passage section <NUM> of area greater than the area of the minimum passage section <NUM> of the first air inlet line <NUM>. The third air inlet line <NUM>, if provided, preferably has in turn a minimum passage section <NUM> of area greater than the area of the minimum passage section <NUM> of the second air inlet line <NUM>.

The minimum passage sections <NUM>, <NUM>, <NUM> can be provided in the air inlet lines <NUM>, <NUM>, <NUM>, upstream or downstream of the solenoid valves <NUM>, <NUM>, <NUM>.

Each air inlet line <NUM>, <NUM>, <NUM> has the inlet end in communication with atmospheric air. The solenoid valves <NUM>, <NUM>, <NUM> can be controlled by the controller <NUM> of the coffee machine <NUM>.

The solenoid valves <NUM>, <NUM>, <NUM> can be of digital (on or off) type or of proportional control type.

The inlet lines <NUM>, <NUM>, <NUM> are optionally provided with an air filter <NUM>, <NUM>, <NUM> preferably positioned upstream of the solenoid valves <NUM>, <NUM>, <NUM> and in particular at the inlet end of the air inlet lines <NUM>, <NUM>, <NUM>.

The circuit <NUM> for supplying air is divided into a first section 3a and a second section 3b that are reciprocally connected in a disconnectable manner.

The first section 3a of the circuit <NUM> for supplying air comprises the air inlet lines <NUM>, <NUM>, <NUM>, the solenoid valves <NUM>, <NUM>, <NUM> and the manifold <NUM>.

The second section 3b of the circuit <NUM> for supplying air comprises the outlet <NUM> of the circuit <NUM> for supplying air.

Also the circuit <NUM> for supplying steam comprises a first section 4a and a second section 4b reciprocally connected in a disconnectable manner.

The first section 4a of the circuit <NUM> for supplying steam comprises an inlet (not shown) of the circuit <NUM> for supplying steam connected to the steam generating means present inside the frame <NUM> of the coffee machine <NUM>.

The second section 4b of the circuit <NUM> for supplying steam comprises the outlet <NUM> of the circuit <NUM> for supplying steam.

The temperature sensor <NUM> is so positioned as to determine the temperature of the emulsified milk, and thus advantageously in the mixing chamber <NUM> as in the point further above. Optionally, the temperature sensor <NUM> can be arranged along the dispensing line <NUM> of the emulsified milk.

The sensor <NUM> is provided with energy and data exchange means <NUM>, because it has to be able to communicate with the controller <NUM>.

The first section 3a of the circuit <NUM> for supplying air and the first section 4a of the circuit <NUM> for supplying steam are mounted inside the frame <NUM> of the coffee machine <NUM>.

Inside the frame <NUM>, there is also a first part 101a of the energy and data exchange means <NUM>.

The second section 3b of the circuit <NUM> for supplying air and the second section 4b of the circuit <NUM> for supplying steam are on the other hand mounted jointly to the mixing chamber <NUM> in a support body <NUM> outside the frame <NUM>.

In the support body <NUM>, there is also a second part 101b of the energy and data exchange means <NUM>.

The two parts101a and 101b are reciprocally connected in a disconnectable manner.

The frame <NUM> of the coffee machine <NUM> supports a connector <NUM> having a connection fitting <NUM> between the first section of circuit 3a for supplying air and the second section of circuit 3b for supplying air, and a connection fitting <NUM> between the first section of circuit 4a for supplying steam and the second section 4b of the circuit <NUM> for supplying steam.

In the connector <NUM>, there is a connection fitting 101c between the first and second part 101a and 101b of the energy and data exchange means <NUM>.

In the solution illustrated, the energy and data exchange means <NUM> is formed by an electric line that connects the temperature sensor <NUM> to the controller <NUM>.

In this case, the first part 101a of the energy and data exchange means <NUM> is a first section of the electrical line, the second part 101b of the energy and data exchange means <NUM> is a second section of the electrical line, and the fitting 101c is an electrical connector that connects the two sections of electrical line.

The connector <NUM> has a part inside the frame <NUM> and a part that through suitable openings in the thickness of the front wall of the frame <NUM> extends outside the frame <NUM>.

At least in the part outside the frame the fittings <NUM>, <NUM> and 101c of the connector <NUM> extend rectilinearly in a direction parallel to the resting surface <NUM> of the coffee machine <NUM>.

The support body <NUM> is connected disconnectably to the connector <NUM>.

The support body <NUM> in particular has a sleeve <NUM> in a form joined to the fitting <NUM> and provided with a suitable gasket <NUM> for seal connection to the fitting <NUM>, and a sleeve <NUM> in a form joined to the fitting <NUM> and provided with a suitable gasket <NUM> for seal connection to the fitting <NUM>.

The sleeves <NUM>, <NUM> are preferably realised as a single piece <NUM> also housing a through channel 101b' where the connector 101c engages that connects the first part 101a to the second part 101b of the energy and data exchange means <NUM>. With reference to the solution disclosed in <FIG>, <FIG>, and <FIG>, the piece <NUM> is also disengageable from the rest of the support body <NUM>, which is thus more easily accessible internally for inspection and cleaning.

The support body <NUM> is connectable to the connector <NUM> with a movement according to a connection axis parallel to the resting surface <NUM> of the coffee machine <NUM>.

In the embodiment of the invention illustrated in <FIG>, the support body <NUM> engages with a container of the milk <NUM>.

The support body <NUM> supports also in this case a milk supply line <NUM> that is connected to the mixing chamber <NUM> and extends into the container of the milk <NUM> until the bottom thereof, and a dispensing line <NUM>, which dispensing line <NUM> is also connected to the mixing chamber <NUM>.

The outlet <NUM> of the circuit <NUM> for supplying steam is shaped as a Venturi tube to generate in the mixing chamber <NUM> a vacuum that draws into the mixing chamber <NUM> air sucked from the circuit <NUM> for supplying air and milk sucked from milk supply line <NUM>.

The support body <NUM> is positioned in front of the front wall of the frame <NUM> and acts in particular as a lid for the container of the milk <NUM>, which in turn rests on a suitable resting surface <NUM> that extends in front of the frame <NUM> from the base of the coffee machine <NUM>.

The dispensing line <NUM> protrudes laterally from the container of the milk <NUM> and above an area of the resting surface <NUM> intended for positioning a collecting cup <NUM> of the product dispensed by the dispensing line <NUM>.

The operation of the emulsifying device is as follows.

It must first be pointed out beforehand that the controller <NUM> is able to recognize the presence of an emulsifying device <NUM> connected to the coffee machine, by first sensor means <NUM> of known type (for example of mechanical or magnetic type), and also to recognize the type of emulsifying device <NUM> present, by second sensor means <NUM>, which is also of known type (for example of mechanical or magnetic type). The presence of the temperature sensor <NUM> is also recognized by the interface of the controller <NUM> with the energy and data exchange means <NUM>.

The controller of the coffee machine <NUM> is programmed with an emulsion programme that is capable of dispensing milk froth regardless of the type of milk used and of the initial temperature of the milk. Optionally, a recognition programme for recognizing the presence of milk can be run by the controller. The operation of these programmes is explained below.

The first step of the programme, after the user has actuated the machine, opens the circuit <NUM> for supplying steam so as to initiate suction of milk into the mixing chamber <NUM> through the Venturi effect.

At this point, the temperature sensor <NUM> is driven to control the temperature of the emulsified milk, thus determining the temperature Tc.

Preferably, the controller can determine the presence or absence of milk by simply comparing the temperature Tc with a predefined safety threshold Ts: if the milk is not present, the detected temperature will rapidly reach the known temperature of the steam, indicating that the milk is missing. Thus if Tc ≥ Ts, the flow of steam is interrupted and the emulsion operation is stopped.

Subsequently, the circuit <NUM> for supplying air to start emulsifying the milk is actuated.

One or more solenoid valves are opened, thus enabling the air to enter the mixing chamber <NUM> and reducing the quantity of milk in the mixture.

As in general milk is at a lower temperature than the air, the temperature detected by the sensor <NUM> will start to increase.

After a predefined lapse of time, the sensor again detects the temperature Tc and compares the temperature with a predefined boiling temperature Te.

If Tc ≥ Te, the flow of air sucked by the Venturi effect in the chamber is reduced by the controller <NUM> acting on one or more solenoid valves, thus permitting automatically an increase in the flow of milk sucked by the Venturi effect in the chamber with a resulting reduction of temperature.

Lastly, the step of detecting and comparing between Tc and Te is repeated until dispensing of the beverage is completed, possibly by acting on the opening of one or more solenoid valves at each cycle.

Through this method control, it is indifferent which type of milk is used in the machine and it is equally indifferent what the initial temperature was of the milk.

In particular, it is shown that the safety temperature Ts of the steam is a value known from the design of the device, whereas the boiling temperature Te can be easily determined by simple emulsion tests and ordinary experimentation with various types of commercially available milk.

Clearly, the number of solenoid valves and the manner in which they are controlled can be varied according to need.

If in an extreme case only one digital solenoid valve is provided, when Tc ≥ Te the flow of air into the chamber is interrupted by the controller <NUM>, which closes the solenoid valve, thus automatically permitting an increase in the flow of milk sucked by the Venturi effect in the chamber, with a subsequent reduction of the temperature.

The temperature and frothing can be regulated with a cyclical control of the state of the solenoid valve during production of the beverage.

The emulsifying device is accordingly able, with a cheap and simple system, to vary with extreme precision the production of froth of the milk regardless of the type of milk used and of the initial temperature of the milk.

Further, through the aforesaid temperature control, it is avoided that spurts of milk are created in the end container due to boiling of the milk in the mixing chamber, with a consequent increase in user safety.

The user is not required to have any particular skill for performing the operation successfully as the contribution of the user is limited to the programme start input. A table is shown below relating to the control owing to the temperature sensor performed with two air solenoid valves Ev1 and Ev2 and a solenoid valve Ev3 along the supply circuit for supplying steam that switches between a mixing chamber supply status and steam discharge status.

The temperature sensor allows the controller to detect the temperature difference and to activate\deactivate the solenoid valves EV1-EV2 in function of the temperature detected in the mixing chamber.

Activating the solenoid valves EV <NUM> \ EV2 influences the quantity of air sucked during steam\milk dispensing and indirectly the efficiency of suction of the milk, compensating the greater temperature detected with the increase in sucked milk with respect to the steam, thus contributing to lowering the total temperature of the emulsion.

The temperature sensor detecting a predefined temperature threshold is able to interrupt dispensing of steam and by the solenoid valve EV3 instantaneously interrupt dispensing of milk in the event for example of absence of milk or an insufficient quantity of milk for completing the preselected recipe.

Claim 1:
A coffee machine (<NUM>) comprising an emulsifying device (<NUM>) for emulsifying milk, comprising a Venturi mixing chamber (<NUM>), a circuit (<NUM>) for supplying air and having an air outlet (<NUM>) connected to the mixing chamber (<NUM>), and a circuit (<NUM>) for supplying steam and having a steam outlet (<NUM>) connected to the mixing chamber, where said circuit (<NUM>) for supplying air comprises at least a first air inlet line (<NUM>) equipped with a first shut-off solenoid valve (<NUM>),
the emulsifying device (<NUM>) comprising a temperature sensor (<NUM>) of the emulsified milk and an energy and data exchange means (<NUM>) for the sensor (<NUM>), characterised in that it comprises an internal controller (<NUM>) programmed to perform the following steps:
a. activating the circuit (<NUM>) for supplying steam to initiate the Venturi effect in the mixing chamber (<NUM>);
b. activating the temperature sensor (<NUM>) for controlling the temperature of the emulsified milk;
c. determining the temperature (Tc) of the emulsified milk, optionally comparing such temperature Tc with a predefined safety temperature (Ts), and in the event in which Tc ≥ Ts interrupting the flow of steam and stopping the emulsion operation;
d. activating the circuit (<NUM>) for supplying air to start emulsifying the milk;
e. determining the temperature (Tc) of the emulsified milk and comparing such temperature Tc with a predefined boiling temperature (Te);
f. if Tc ≥ Te activating the circuit (<NUM>) for supplying air to reduce the flow of air and therefore reduce the temperature in the mixing chamber (<NUM>);
g. repeating steps e-f until the completion of the dispensing..