DEVICE AND PROCESS FOR PREPARING FROTHY MILK

Abstract

Frothing device (1) to froth a beverage, especially milk, comprising: a steam source (2); a source (3) of pressurized air; a dispensing unit (4) to dispense air and steam to the beverage; an air flow rate regulating device (6) arranged downstream of the source (3) of pressurized air; a control unit (16) programmed to operate, in use, the simultaneous supply of steam and air to the dispensing unit (4), respectively from the steam source (2) and from the source (3) of pressurized air.

Claims

1. Frothing device (1) to froth a beverage, especially milk, comprising: a steam source (2); a source (3) of pressurized air; a dispensing unit (4) to dispense air and steam to the beverage, immersible in the beverage; an air flow rate regulating device (6) arranged downstream of the source (3) of pressurized air; a control unit (16) programmed to operate, in use, the simultaneous supply of steam and air to the dispensing unit (4), respectively from the steam source (2) and from the source (3) of pressurized air.

2. Device according to claim 1, wherein said control unit is programmed to regulate, in use, the air flow rate downstream of said source by means of said air flow rate regulating device (6) as a function of the dispensing time and/or the temperature of the beverage.

3. Device according to one of the preceding claims, wherein said source (3) of pressurized air comprises a pump (11) and/or said steam source comprises a boiler (2a), a valve (8) being arranged downstream of said boiler (2a), wherein said control unit is programmed to control said pump (11) and/or said valve (8).

4. Device according to one of the preceding claims, further comprising a sensor (15) to detect the temperature of the beverage during the frothing thereof.

5. Device according to one of the preceding claims, wherein the flow rate regulating device (6) is configured to divert part of the air flow coming out of the source (3) of compressed air.

6. Device according to claim 5, wherein said source (3) of pressurized air is connected with said dispensing unit (4) immersible with a first duct (7) and the flow rate regulating device (6) is configured to divert part of the air flow coming out of the source (3) of compressed air towards another duct (6a).

7. Device according to claim 5, wherein the flow rate regulating device (6) is configured to divert part of the air flow coming out of the source (3) of compressed air towards the outer environment.

8. Device according to one of the preceding claims, further comprising: a first duct (5) for connecting, directly or indirectly, said steam source (2) to said dispensing unit (4); a second duct (7) for connecting, directly or indirectly, said pressurized air source (3) and said dispensing unit (4), and wherein said air flow rate regulating device (6) comprises a diversion duct (6a) branching off from said second duct (7), and preferably a valve (6b) operatively connected to said control unit (16).

9. Device according to claim 8, wherein said valve is a regulation valve (6b) positioned on said diversion duct (6a) and preferably wherein two devices adapted to determine a reduction of the passage section (19; 18) are respectively arranged upstream of the pump (11) and downstream of the regulation valve (6b).

10. Device according to one of the preceding claims, wherein a valve (5a), preferably an electrovalve, is arranged downstream of said steam source (2) and is configured at least to alternatively allow or prevent the steam supply from said steam source (2) to said dispensing unit (4).

11. A machine (100) for preparing beverages, comprising a frothing device according to one or more of the preceding claims.

12. Process for frothing a beverage, especially milk, by immersing a dispensing unit of a device according to one of claims 1 to 10, or with a machine according to claim 11, wherein the control unit carries out the steps of: i. operating the simultaneous supply of steam and air from said steam source and said pressurized air source to said dispensing unit; ii. regulating the air flow rate by means of said air flow rate regulating device (6).

13. Process according to claim 12, wherein the pressurized air source comprises a pump (11), and a valve being arranged downstream of the steam source and, in said step i, the control unit (16) controls the operation of said pump simultaneously with the opening of said valve, so that to allow a simultaneous supply of air and steam to said dispensing unit.

14. A non-transitory data medium adapted to be read by a computer and/or logic unit (16), said medium comprising instructions that, when read by a control unit of a device according to one of claims 1 to 10, induce said device (1) to carry out the steps i and ii according to said claim 12.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0030] With reference to the figures attached, exemplary and non-limiting embodiments of the present invention are now discussed, in which:

[0031] FIG. 1 is a scheme of a device according to the present invention;

[0032] FIG. 2 is a graph depicting a possible trend of the air pressure as a function of the dispensing time.

EMBODIMENTS OF THE INVENTION

[0033] A frothing device 1 to froth a beverage, especially milk, according to the present invention comprises a steam source 2 and a source 3 of pressurized air.

[0034] Different types of sources 2, 3, known in the art, adapted to supply steam and pressurized air, can be used. Typically, the steam source 2 comprises a boiler 2a. In preferred embodiments, such as the one schematically shown in FIG. 1, the source 3 of pressurized air comprises a pump 11 and, preferably, also a jet or gicleur 19, or any device adapted to determine a reduction of the passage section upstream of the pump 11.

[0035] According to a possible embodiment, the diameter of the passage section provided by the gicleur 19 is equal to 0.3 mm, however other passage section dimensions depending on the constructive requirements are not to be excluded.

[0036] A dispensing unit 4, typically in the form of a wand or similar element, is configured to dispense air and steam (coming from the respective sources 3, 2) to a beverage, typically by at least partially immersing the dispensing unit 4 into the beverage. Air and steam can be dispensed through two separate nozzles of the dispensing unit 4 or, preferably, in the form of mixture.

[0037] Ducts 5, 7 are typically arranged between the sources 2, 3 and the dispensing unit 4 so that to allow the supply of steam and air to the dispensing unit 4.

[0038] In particular, a first duct 5 fluidically connects the steam source 2 to the dispensing unit 4.

[0039] A second duct 7 fluidically connects the source 3 of pressurized air to the dispensing unit 4.

[0040] As previously discussed, the ducts 5, 7 are not necessarily directly connected to the dispensing unit 4. In possible embodiments, the fluidic connection between the source and the dispensing unit can be indirect, i.e. by means of a further duct. For example, in possible embodiments, such as the one shown, the first duct 5 directly connects the steam source 2 to the dispensing unit 4, whereas the second duct 7 indirectly connects the source 3 of pressurized air to the dispensing unit 4. In particular, the second duct 7 connects to the first duct 5, so that to convey an air and steam mixture to the dispensing unit 4. Whenever the first and second ducts merge into a single duct, preferred embodiments provide that a connecting element 12, for example a T-joint, is provided at the connecting point between the first and second ducts and configured so that to allow the inflow of air into the steam flow, for example by exploiting the Venturi effect.

[0041] In possible alternatives, steam and air can arrive separately to the dispensing unit 4, i.e. along ducts (or anyhow fluidic paths) separated from each other. Preferably, the first duct 5 is provided with a valve 5a, preferably an electrovalve, adapted to at least alternatively allow and prevent the steam flow towards the dispensing unit 4. Typically, as discussed, the steam source comprises a boiler 2a, whereby the steam is pressurized upstream of the valve 5a. The opening of the valve 5a thus allows the steam present in the first duct 5 upstream of the valve 5a to reach the dispensing unit 4.

[0042] According to a possible aspect, the valve 5a can be a three-way valve, so that to be able to channel the steam (or condensation, for example in the resting status of the device 1) towards a discharge duct 5b. The valve 5a can be a proportional valve, or a valve provided only with open and closed statuses.

[0043] An air flow rate regulating device 6 is present downstream of the source 3 of pressurized air, i.e. typically downstream of the pump 11.

[0044] Different types of flow rate regulating devices 6 can be used. Preferably, such as for example in the embodiment shown, the flow rate device 6 is configured to divert part of the air flow coming out of the air source 3 towards a different direction, typically towards another duct or directly to the outer environment. In other words, the flow rate regulating device 6 is typically configured to withdraw part of the air flowing downstream of the compressed air source 3.

[0045] According to a possible aspect, the flow rate regulating device comprises a diversion duct 6a branching off from the second duct 7. A valve 6b, typically an electrovalve, is preferably used to control the air flow through the diversion duct 6a. The valve can be a proportional valve, i.e. a valve whose degree of opening can be controlled, so that to assume one or more intermediate positions between the open or closed position. In other possible solutions, the valve can be a valve whose duty cycle can be controlled, so that to quickly determine the open and closed statuses of the valve in succession, so that to control the amount of air flowing in the diversion duct 6a. According to an aspect, such as shown for example in FIG. 1, the valve 6b is arranged solely on, i.e. connected with, the diversion duct 6a, preferably spaced from the branching point of duct 6a with duct 7.

[0046] Typically, the diversion duct 6a discharges into the environment. Preferably, a jet or gicleur 18, or any other device adapted to determine a reduction of the passage section, is arranged downstream of the valve 6b. According to a possible embodiment, the diameter of the passage section provided by the gicleur 18 is equal to 0.2 mm, however other passage section dimensions depending on the constructive requirements are not to be excluded.

[0047] In general, according to an aspect of the present invention, the jet or gicleur 18 placed in the diversion duct 6a preferably downstream of the valve 6b, has a smaller passage section with respect to the passage section of the jet or gicleur 19 placed upstream of the source 3 of pressurized air, preferably placed upstream of the pump 11.

[0048] Part of the air coming out of the source 3 of compressed air can be channeled towards the diversion duct 6a, so that to regulate accurately (and, in particular, decrease accurately) the air flow rate flowing inside the second duct 7 downstream of the diversion duct 6a, i.e. the air flow rate being supplied to the dispensing unit 4.

[0049] In general, the flow rate regulating device 6 is configured so that to allow to regulate the air flow rate downstream of the compressed air source 3.

[0050] According to a possible aspect, downstream of the flow rate regulating device 6, a non-return valve 8 adapted to prevent the return of fluid (air, or steam or air/steam mixture) towards the compressed air source 3, can be present.

[0051] The device 1 also preferably comprises a sensor 15 detecting the temperature of the milk during the frothing step thereof.

[0052] Temperature sensors of this type are known, available on the market and present on some coffee machine models.

[0053] The device 1 further comprises a control unit 16 connected with at least the flow rate regulating device 6 and configured to be able to operate the simultaneous dispensing of air and steam from the respective sources 3, 2 to the dispensing unit 4.

[0054] In particular, in preferred embodiments, the control unit 16 is connected with the valve 5a and with the pump 11, so that to send a command which actuates the pump 11 and opens the valve 5a. In other words, the control unit 16 is programmed so that the dispensing of steam depends on the dispensing of air, so that the two fluids are always dispensed simultaneously (from separate nozzles or in the form of mixture).

[0055] It should be noted that the logic connections between the control unit 16 and the respective components are shown by dotted lines in FIG. 1.

[0056] Therefore, in general, the control unit is programmed so that the air and steam are simultaneously conveyed to the dispensing unit 4 (separated or in the form of mixture), and to control in a precise way the air flow rate reaching the dispensing unit 4, by means of the flow rate dispensing device 6. In a known way, the control unit 16 can also be connected to other components, for example with the temperature sensor of the beverage 15.

[0057] An aspect of the present invention further provides that the frothing device 1 to froth milk is integrated (or connected) with a machine 100 for preparing beverages.

[0058] The process according to the invention provides to immerse the dispensing unit 4 into the beverage and to simultaneously supply steam and air to the dispensing unit 4 so that to dispense air and steam therefrom, preferably an air-steam mixture, to froth the beverage; simultaneously, by means of the flow rate regulating device 6, it is possible to regulate the air flow that reaches the dispensing unit 4. Such control can be carried out by means of an open-loop control (for example the air flow rate regulation can be controlled as a function of the type or quality of beverage selected by a user), or a closed-loop control, by the feedback provided by a respective sensor.

[0059] In possible solutions, the flow rate regulator 6 can be operated as a function of the dispensing time, i.e. the air flow rate can be regulated in a predetermined way while dispensing. Different types of beverages can involve different behaviors of the flow rate regulator.

[0060] In addition or as an alternative, the flow rate regulator 6 can be operated as a function of the temperature of the beverage, for example detected by the temperature sensor 15.

[0061] It should be noted that such regulation by means of the regulating device 6 involves a modification (typically a reduction) of the air flow rate towards the dispensing unit 4. However, the control unit 16 is programmed so that the dispensing unit 4 always dispenses, in use, both air and steam, i.e. the flow rate regulating device 6 is configured to modify the air flow rate, but not to prevent the air from being dispensed from the dispensing unit 4, while steam is dispensed from it, such as for example schematically shown in FIG. 2.

[0062] In particular, FIG. 2 shows a possible trend of the air pressure (measured in the second duct 7 downstream of the branching point of the diversion duct 6a and shown on the axis Y in the graph of FIG. 2, in bars) as a function of the dispensing time (shown on the axis X in the graph of FIG. 2).

[0063] In particular, at time t0, the control unit 16 operates the simultaneous activation of the pump 11 and the opening of the valve 5a. In this step, the valve 6b is also open, so that to divert part of the air flow towards the outside, through the diversion duct 6a. The air pressure in the duct 7 thus typically reaches a first pressure value p1 (for example equal to about 0.5 bars). Afterwards, at time t1, the valve 6b is closed, so that to interrupt the air flow in the diversion duct 6a. The air pressure in the second duct 7 rises. Typically, the air pressure in the second duct 7 rises until reaching a second pressure value p2 (for example of about 0.9 bars), greater than the first pressure value p1. The control unit can thus operate the valve 6b so that to further vary the air pressure value. For example, in the embodiment shown in FIG. 2, at time t2, the valve 6b is open, so that to decrease the air pressure to a third value p3 (generally substantially equal to the first value P1), and is closed again at time t3, so that to cause a pressure increase up to a fourth value p4 (typically equal to the second value p2).

[0064] Obviously, although reference was made to the pressure values p1 and p2, respectively of about 0.5 bars and 0.9 bars (for example with reference to FIG. 2), such values are not limiting and further pressure values can be used in further possible embodiments. It should be not that the pressure value of the steam dispensed from the source 2, for example a boiler, can also be selected conveniently. For example, according to a possible embodiment, the steam in the boiler can have a pressure of about 1.1.-1.2 bars. Embodiments wherein the steam pressure, for example in the boiler, is between 0.8 bars and 1.9 bars are not however excluded.

[0065] The control unit 16 thus provides to simultaneously stop the dispensing of steam and air on command, or after a preset time, or upon reaching a preset temperature (for example by using a signal from the temperature sensor 15). It should be noted that the trend of the air pressure following the interruption of the dispensing of steam and air is not shown in FIG. 2. In a predictable way, the air pressure in the duct decreases to zero, i.e. returns to the environmental pressure value.

[0066] In particular, in preferred embodiments, following a user command (for example following the pressure of a user on a button in a respective interface), the control unit 16 activates the pump 11 and, simultaneously, operates the opening of the valve 5a, so that to simultaneously dispense air and steam (typically in the form of mixture) from the dispensing unit 4. The dispensing unit 4 is typically at least partially inserted into the milk (or the beverage to be frothed) so that the air and steam are dispensed into the milk.

[0067] The step of heating and frothing the milk occurs from this point on, until the temperature sensor 15 detects the reaching of a programmed temperature, which is typically in the range between 50° C. and 80° C., preferably between 55° C. and 65° C. If necessary, the air flow rate reaching the dispensing unit 4 (and thus delivered by it into the beverage to be frothed) is regulated by means of the flow rate regulating device 6, for example by opening the valve 6b, so that to channel part of the air flow coming out of the pump 11 into the diversion duct 6a.

[0068] Consequently, the control unit 16 closes the valve 5a and deactivates the pump 11, so that to interrupt (simultaneously) both the flows of air and steam from the dispensing unit 4.

[0069] According to the invention, it is also possible to provide a non-transitory data medium 200 adapted to be read by the logic unit 16, so that to allow the latter to carry out the method discussed above.

[0070] It should be noted that, even though reference was made to an exemplary embodiment in the previous description, the invention can also be implemented according to a high number of variants. In fact, the embodiment described is merely exemplary and must not be understood in any way as the protection scope, configuration or application of the invention. On the contrary, the description above should be considered as a guide for implementing at least one embodiment of the invention; a number of modifications to those described may be made to the exemplary embodiment, without departing from the protection scope of the invention.