ITTO20070039A1 - DEVICE FOR HEATING AND / OR FOAMING A BEVERAGE - Google Patents

Description

Description of the Industrial Invention entitled: "Device for heating and / or frothing a beverage"

TEXT OF THE DESCRIPTION SECTOR OF THE TECHNIQUE

The present invention relates, in general, to a device for heating and / or foaming a beverage, for example milk, by means of water vapor.

In particular, the present invention refers to a device applied to an espresso coffee machine for preparing hot milk or cappuccinos and, in the following description, reference is made to this application, which is considered preferred.

NOTE ART

Devices for heating and / or frothing milk are known.

For example, from document EP0607759A1 a device for preparing foamed beverages is known to be used associated with a machine for preparing coffee and other hot beverages.

The known device comprises a lance which, controlled by a manual valve, has a first chamber into which the steam is introduced, and a second chamber, from which the steam comes out; the two chambers are connected by means of a passage area, with a narrow section, in which there is a hole communicating with the external environment.

The flow of steam in the restricted section causes, due to the Venturi effect, a pressure decrease sufficient to guarantee the suction from the external environment of air which, mixed with the steam, leaves the second chamber and is introduced into the liquid, for example milk, and foam it.

A first problem of this known art is that the lance is effective for the preparation of foamed beverages, while it is ineffective for the preparation of non-foamed hot beverages since the restricted section area generally involves either the introduction of either air that of steam in the beverages with consequent foaming of the beverage or the need for an accurate control of the manual valve to limit the flow of steam and the consequent intake of air due to the Venturi effect.

Of course, controlling the flow of steam entails the further problem that the time for preparing heated drinks is much greater than the time required for preparing foamed drinks.

From document EP0472272A2 an automatic machine for preparing espresso coffee is known which comprises a device for obtaining hot or frothed milk to be added to espresso coffee.

The device of the known machine comprises two valves for introducing the steam through a duct placed upstream of a chamber having a narrow section with respect to the duct; the chamber, operating by the Venturi effect, comprises an orifice for the inlet of air from the external environment.

The two valves of the device have different flow rates from each other.

Consequently, the opening of the valve at a higher flow rate, allowing a greater flow of steam into the chamber, is suitable for allowing the preparation of frothed milk, since the pressure decrease in the chamber due to the Venturi effect is high.

Closing the valve with a higher flow rate and opening the one with a lower flow rate, on the other hand, allows the preparation of hot milk, as the pressure decrease in the chamber due to the Venturi effect is minimal and therefore not sufficient to allow air to flow from the environment in the room.

This known art, while allowing the preparation of both hot and foamed milk, presents, in any case, the problem that the preparation of hot milk generally requires very long times and in any case longer than those necessary for the preparation of foamed milk.

This problem is, as easily understood by a technician in the sector, particularly felt in public premises where the time for preparing the drinks must be extremely reduced to allow both short service times and good satisfaction on the part of the public.

The Applicant has essentially observed that there are currently no devices on the market which, regardless of whether hot or foamed drinks must be prepared, guarantee extremely short preparation times, in particular as regards hot drinks. DESCRIPTION OF THE INVENTION

The object of the present invention is a device for heating and / or frothing a beverage that does not have the defects and limitations highlighted above of the known art.

The purpose is achieved by the device for heating and / or frothing a beverage as claimed.

The present invention also relates to a method for heating and / or foaming beverages as well as a beverage preparation machine comprising the device.

The claims form an integral part of the technical teaching provided herein about the invention.

In accordance with a preferred embodiment, the device according to the invention comprises a first conduit having a first opening and closing valve to allow steam to flow into the conduit and a second conduit having both a second opening and closing valve to allow steam to flow into the conduit. conduit that a Venturi unit configured to operate by the Venturi effect when the first valve is closed.

In accordance with a further feature of the present invention, the Venturi unit is connected to a third valve configured to prevent, in certain situations, the Venturi unit from operating due to the Venturi effect.

According to another feature of the present invention, the opening and closing of the valves is controlled by a control unit controlled by a control unit.

In accordance with yet another feature of the present invention, the device comprises a temperature detecting device for detecting the instantaneous temperature of the beverage and the control unit is configured to selectively control, according to the instantaneous temperatures of the beverage, the opening and closing of valves to prepare heated and / or foamed drinks.

BRIEF DESCRIPTION OF THE FIGURES

These and other characteristics and advantages of the present invention will become clear from the following description of preferred embodiments made by way of non-limiting example with the aid of the attached figures, in which elements indicated with the same or similar numerical reference indicate components which have same or similar functionality and construction and in which:

Fig. 1 represents an overall diagram of the device according to the invention in a preferred embodiment;

Fig. 2 shows a detail of the device of Fig. 1 in a further embodiment; and Fig. 3 shows a detail of the device of Fig. 1 in a third embodiment.

DESCRIPTION OF A PREFERRED FORM OF PRODUCTION

With reference to Fig. 1, a device 10 for heating and / or frothing a beverage 19, for example milk, applied to an espresso coffee machine, comprises a first and a second duct, 21 and 22 respectively, having a common inlet connected to a boiler 12, of a known type, able to generate, for example, steam under pressure, and a common outlet connected to a mixing element 14, for example a lance of a known type able to introduce and mix the steam under pressure, possibly including of air, as will be described in detail below, with the liquid 19 contained, for example, in a container.

The device 10 also comprises a control unit 25 and a control unit 39, connected to the control unit 25 and adapted, for example, to transmit commands from a user to control the operation of the device 10.

The control unit 25 is configured, as will be described in detail below, to control the operation of the device 10 by means of programs developed during the design phase of the device and stored, for example, in the same control unit 25.

The first duct 21 comprises a first valve 31, for example a solenoid valve with an internal diameter of 3.5 mm, able to be controlled in opening and closing by the control unit 25 to make the steam under pressure flow or not flow from the boiler 12 to the lance 14.

The second duct 22, preferably with an internal diameter equivalent or substantially equivalent to that of the first duct, comprises, upstream, a second valve 32, for example a solenoid valve with an internal diameter of 3.5 mm, able to be controlled in opening and closing by the control unit 25 to make the steam under pressure flow or not flow from the boiler 12 to the lance 14, and, downstream, in the direction of the lance 14, a duct element 22a operating, preferably, by the Venturi effect.

The duct element (Venturi or Venturi group) 22a comprises a portion of duct 42, for example with a diameter of 2.5 mm, connected upstream and downstream of the second duct 22 and an orifice 43, for example with a diameter of 1.5 mm, obtained in the section of duct 42 and communicating directly, as shown in Fig. 2, with the external environment at atmospheric pressure.

According to a preferred embodiment, shown in Fig. 1, the orifice is connected to a valve (Venturi valve) 33, for example a solenoid valve with a diameter equal to that of the orifice, suitable for being controlled in opening and closing. from the control unit 25 to allow or not the entry of air from the external environment into the Venturi 22a or, vice versa, the exit of steam or not from the orifice 43 towards the external environment.

According to a variant of the preferred embodiment, the Venturi valve 33 is, for example, a non-return valve designed to prevent only the exit of steam from the orifice 43 towards the external environment; naturally, as easily understood by a person skilled in the art, such a valve does not need to be controlled by the control unit 25.

According to a third embodiment, the orifice 43 is connected to a further portion of duct 44 (Fig. 1, Fig. 3) having a diameter smaller than that of the orifice 43, for example a diameter of 0.5 mm.

This embodiment, as will be described in detail below, is suitable for reducing the quantity of air introduced through the Venturi 22a and allows to obtain a finer foaming than that obtainable with the orifice 43.

In all the embodiments, preferably, a temperature detection device 27 is provided, for example a temperature sensor or thermometer connected, in a known way, to the control unit 25 and able to transmit indicative signals to the control unit 25 the temperature of the liquid 19 in which the lance 14 is immersed for the preparation of heated or foamed drinks.

The control unit 25 of the device 10 is configured, as will be described in detail below, to control the operation of the device 10 by means of programs developed in the design phase of the device and stored, for example, in the same control unit 25 and comprises , preferably, a microcontroller 51 of a known type, for example a microcontroller model MB90F497G of the company FUJITSU, connected or including a multi-port input-output interface (I / O interface) 55.

In the preferred embodiment, the I / O interface 55 is connected to the first and second valves, 31 and 32 respectively, to the temperature detection device (thermometer) 27, to the control unit 39 and, if present, to the Venturi valve 33 .

The control unit 39, for example a two-key keyboard, is able to transmit to the control unit 25, for example following the activation of one of the keys, commands for the activation and / or deactivation of the various functions of the device 10; in particular, in the preferred embodiment, the control unit (keyboard) 39 comprises a first key 39a, designed to command the control unit 25 to prepare a heated and foamed beverage, and a second key 39b arranged, so corresponding, to command the preparation of a heated drink. Even more preferably, the keypad 39 is associated with or comprises a signaling unit 38, for example a buzzer and / or an LED, connected to the control unit 25 and able to signal the completion of the activated command in an audible and / or visual manner. using the keys 39a or 39b, as explained in detail below.

Preferably, the device 10 is also associated with a parameter setting unit 37, for example a keyboard with display, of a known type, connected to the control unit 25 and suitable for setting the working parameters of the device 10, to be stored for example in the 'control unit.

The operation of the device described up to now is reported below, taking as reference the embodiment shown in Fig. 1, which comprises the Venturi valve 33 controlled by the control unit 25.

In describing the operation, moreover, a starting condition is also taken as reference in which the first and second valves, 31 and 32, and the Venturi valve 33 are closed and the lance 14 is immersed in the drink or liquid (milk) 19 contained. in a bowl.

Finally, it is also taken as reference that the boiler 12 operates, for example, in a pressure range between 0.8 and 1.4 bar and that a maximum heating temperature of the milk is envisaged, for example a temperature of 70 °.

Of course, in other embodiments the above values may be different from those indicated, without thereby departing from the scope of what is described and claimed.

The operation of the device 10 for preparing a beverage, for example milk, heated and foamed is the following.

Following the activation, in a first phase, of the key 39a designed to activate the preparation, for example, of heated and frothed milk (whipped), the control unit 25, on the basis of the programs developed in the design phase of the device 10, keeps the Venturi valve 33 closed and controls the opening of both the first valve 31 and the second valve 32 which thus allow the rapid flow of steam from the lance 14 and an equally rapid heating of the milk. During this phase, if the Venturi valve 33 is missing, since both valves 31 and 32 are open, there is an overpressure in the Venturi 22a, estimated for example of 50 mbar above the ambient atmospheric pressure, which prevents the air flow from the external environment into the Venturi 22a.

During this phase, if the non-return valve is present, the flow of steam to the external environment is in any case prevented.

In a second step, for example following the indication by the thermometer 27 to the control unit 25, of a first predetermined temperature, for example a temperature of 30 °, the control unit 25, on the basis of the programs developed in the design phase of the device 10, it commands the closing of the first valve 31 and the opening of the Venturi valve 33.

Following the closing operation of the first valve 31, a vacuum is generated in the Venturi 22a which is suitable for allowing air to flow from the external environment into the steam.

Experimentally, the Applicant has found that, on the basis of the pressure values foreseen in the boiler 12, the pressure in the Venturi is between 260 and 130 mbar, below the atmospheric pressure of the environment, and such as to allow the flow of air from the external environment in the duct section 42.

The air mixed with the steam reaches the lance 14 and then to the milk 19 contained in the container where the frothing of the milk begins, which it mounts by incorporating tiny air bubbles inside it. In this phase, the steam part of the air / steam mixture exiting the lance 14 continues to heat the milk, naturally with a speed lower than that of the first phase since the steam arrives only from the second duct 22. However, this slow heating situation it is ideal for the formation of a high quality foam or cream.

In a third step, for example following the indication by the thermometer 27 to the control unit 25, of a second predetermined temperature, for example a temperature of 55 °, the control unit 25, on the basis of the developed programs in the design phase of the device 10, it commands the opening of the first valve 31 and the closing of the Venturi valve 33. In this phase, similarly to what occurs in the first phase, there is a high steam flow to the lance and a corresponding high speed milk heating.

During this phase, if the Venturi valve 33 is not present, the indications given for the first phase are valid.

In a fourth phase, for example following the indication by the thermometer 27 to the control unit 25, of the maximum heating temperature of the milk, the control unit 25, based on the programs developed in the design phase of the device 10, commands the closure of the first and second valves, 31 and 32 respectively, and signals, by means of the signaling unit 38, the completion of the preparation of the frothed milk.

The operation of the device 10 for preparing a heated beverage, for example milk, is as follows.

Following the activation, in a first phase, of the key 39b designed to activate the preparation, for example, of heated milk, the control unit 25, on the basis of the programs developed in the design phase of the device 10, keeps the Venturi valve 33 and controls the opening of both the first valve 31 and the second valve 32 which thus allow, in a similar way to what has already been described for the first stage of the preparation of frothed milk, the rapid flow of steam from the lance 14 and a heating as fast as milk.

During this phase, all the indications already provided for the first phase of the preparation of the frothed milk are valid.

In a second phase, for example following the indication by the thermometer 27 to the control unit 25, of the maximum heating temperature of the milk, the control unit 25, based on the programs developed in the design phase of the device 10, controls the closure of the first and second valves, 31 and 32 respectively, and signals, by means of the signaling unit 38, the completion of the preparation of the heated milk.

On the basis of what has been described, in the preferred embodiment, at least three working temperatures are provided for the preparation of frothed milk, stored for example in the control unit.

A first working temperature tl corresponding to the temperature, for example 30 °, in which the introduction of air into the steam is foreseen.

A second working temperature t2 corresponding to the temperature, for example 55 °, in which the end of the introduction of air into the steam is expected.

A third working temperature t3, for example 70 °, corresponding to the maximum heating temperature of the milk.

According to one of the possible embodiments, it is provided that the third temperature t3 is set and possibly stored in the control unit by means of the parameter setting unit (auxiliary keyboard) 37 and that the first and second temperatures, tl and t2 respectively , are determined by the control unit 25 and stored on the basis of foam level parameters (for example low, medium, high) set by means of the auxiliary keyboard 37.

As easily understood by a person skilled in the art, as the foam level set increases, the control unit is able to determine, on the basis of the programs developed during the design phase of the device 10, temperature intervals between tl and t2 thus increasing to extend the temperature range and, consequently, the time in which the air is mixed with the steam.

Of course, in other embodiments it is envisaged that it is possible to directly set all the temperatures, t1, t2 and t3 respectively.

The presence of the Venturi valve 33, as easily understood by a technician in the sector, allows, while keeping the Venturi valve 33 closed, the heating of the beverage at variable speed, for example by providing for the setting of heating speed parameters (for example low , medium, high) by means of the auxiliary keyboard 37.

In fact, by keeping the Venturi valve 33 always closed and checking the opening and closing of the first and second valves, 31 and 32 respectively, it is possible to vary the heating speed of the beverage without it being foamed.

This feature is particularly useful if you want to prepare hot drinks, such as hot chocolate or mulled wine. In such cases, in fact, a too high heating speed can compromise the quality of the result, while with other beverages it is possible to use higher heating speeds.

The preferred embodiment provides for the presence of a thermometer associated with the lance 14 and connected to the control unit 25.

Of course, in other embodiments, the thermometer may not be present and the control for the preparation, for example, of foamed beverages can be carried out by the control unit on the basis of parameterizable times corresponding, for example, to the time provided for reaching the temperature tl, at the time set for reaching temperature t2 and at the time set for reaching temperature t3. The same method is also applicable for the preparation of heated drinks.

Of course, obvious modifications and / or variations are possible to the above description, in the dimensions, shapes, materials, components, circuit elements, and connections, as well as in the details of the illustrated construction and method of operating without departing from the invention as specified. in the following claims.

Claims (16)

CLAIMS 1. Device for heating and / or frothing a beverage (19) comprising - a first conduit (21) connectable upstream to a steam source and downstream to mixing means (14) suitable for introducing and mixing at least the steam in said beverage, said first conduit having a first valve (31) configured to be open and closed and let steam flow or not flow in the duct; - a second conduit (22) which can be connected upstream to the steam source and downstream to said mixing means (14), said second conduit having a second valve (32) configured to be open and closed and make the steam in the duct; characterized by what - a first of said two ducts (21, 22) comprises a Venturi unit (22a) configured to operate by the Venturi effect to mix air with said steam in said first of said two ducts when a second of said two ducts is closed. 2. Device according to claim 1 characterized by - a further valve (33) connected to the Venturi group (22a) and configured to allow air to flow in said Venturi group and not to allow steam to flow outside said one of said two ducts. 3. Device according to claim 1 characterized by that said Venturi group (22a) comprises an orifice (43) having a determined internal diameter and is connected to a portion of duct (44) having a corresponding internal diameter smaller than the internal diameter of said orifice. 4. Device according to claim 1, 2 or 3 characterized by - a control unit (25) connected to said first and second valves (31, 32) and configured to control the selective opening and closing of said first and second valves (31, 32). 5. Device according to claim 4 characterized by - a third valve (33) connected to the Venturi group (22a); and hence that said control unit (25) is configured to control the selective opening and closing of said third valve (31, 32). 6. Device according to claim 4 or 5 characterized by - temperature detection means (27) associated with said mixing means (14), connected to said control unit (25) and able to transmit to said control unit signals indicative of the temperature of said beverage (19). 7. Device according to claim 6 characterized in that said control unit is configured to control the heating and / or foaming of the beverage (19) on the basis of the temperature detected by said temperature detection means (27). 8. Device according to any one of claims 4 to 7 characterized by - a control unit (39) connected to said control unit (25) and comprising control means (39a, 39b) adapted to selectively control the preparation of a heated or foamed beverage. 9. Device according to any one of claims 4 to 8 characterized by - a parameter setting unit (37) connected to said control unit (25) and comprising parameter setting means configured to store in said control unit parameters to be used for the preparation of a heated or foamed beverage. 10. Device according to claim 9 characterized in that said parameters comprise at least one temperature range (tlt2) for the preparation of a foamed beverage. 11. Method for heating and / or frothing a beverage (19) with a device comprising a first conduit (21), having a first valve (31), and a second conduit (22), having a second valve (22) and a Venturi unit (22a) configured to operate by the Venturi effect to introduce air into said second duct (22); said first and second ducts being connectable upstream to a steam source (12) and downstream to mixing means (14); the method being characterized by the steps of - opening said first and said second valves (21, 22) to heat said beverage; And - closing said first valve (21) and opening said second valve (22) to activate said Venturi unit (22a) to operate by the Venturi effect. 12. Method according to claim 11 characterized in that said respective steps of opening said first and said second valve (21, 22) and closing said first valve (21) and opening said second valve (22) respectively comprise the step of - activating control means (39) connected to a control unit configured to control the opening and closing of said first and second valves (21, 22). 13. Method according to any one of claims 11 to 12, characterized in that the steps of - detecting temperature values in the vicinity of said beverage (19); command the opening and / or closing of said first and said second valve (21, 22) as a function of the detected temperature. 14. Method according to claim 13 characterized in that said step of controlling the opening and / or closing of said first and of said second valve (21, 22) comprises the steps of controlling the opening of said first and second valve (21, 22) until a first temperature value (t1) is reached; - command the closing of said first valve (21) and the opening of said second valve (22) in a temperature range between said first temperature value (tl) and a second temperature value (12) higher than the first value temperature (tl); - controlling the opening of said first and second valves (21, 22) until a third temperature value (13) greater than or equal to said second temperature value (12) is reached. 15. Method according to any one of claims 11 to 14 characterized by the further step of - controlling the introduction of air into said Venturi unit (22a) by means of a third valve (33) whereby said beverage can be heated by controlling the closing of said first valve (21) and the opening of said second valve (22). 16. Machine for preparing hot drinks, in particular espresso coffee, characterized in that it comprises a device as claimed in claims 1 to 10.