ESPRESSO COFFEE MACHINE AND RELATIVE DEVICE FOR CONTROLLING THE EMULSION OF THE COFFEE-BASED BEVERAGE

Abstract

An espresso coffee machine comprising a main boiler, a dispensing group, a secondary boiler provided, a main water inlet circuit, where the main water inlet circuit has a pump that applies a predetermined pressure value to the water, the machine further including a dispensing valve, an air inlet circuit hydraulically connected to the brewing chamber of each dispensing group, a compressor to inject air at a predefined pressure value in the brewing chamber of each dispensing group and at least one heating element arranged to inject air at a predetermined temperature value into the brewing chamber of each dispensing group.

Claims

1. Espresso coffee machine comprising: a main boiler, configured for producing hot water and steam; at least one dispensing group, configured for preparing coffee and physically and functionally independent from said main boiler; a secondary boiler physically and hydraulically connected to each dispensing group, said secondary boiler being configured to keep the water for dispensing coffee at a predetermined temperature value checked by a temperature probe; a main water inlet circuit for inletting water from the water supply network, hydraulically connected to the main boiler and to the secondary boiler of each dispensing group, said main water inlet circuit comprising at least one pump that applies a predetermined pressure value to the water; and an electronic control unit, a dispensing valve, which determines the start and the end of the distribution, letting the water pass from the secondary boiler of each dispensing group to a brewing chamber of said dispensing group; an air inlet circuit, hydraulically connected to the brewing chamber of each dispensing group; at least one compressor, positioned on the air inlet circuit, electronically controlled by the electronic control unit and configured for injecting air at a predetermined pressure value into the brewing chamber of each dispensing group; and at least one heating element, positioned on the air inlet circuit, electronically controlled by the electronic control unit and configured for injecting air at a predetermined temperature value into the brewing chamber of each dispensing group.

2. Espresso coffee machine according to claim 1, wherein it comprises at least one filter, positioned on the air inlet circuit upstream of the compressor, said filter being configured for filtering the air sucked by the compressor and forced into the brewing chamber of each dispensing unit through the heating element.

3. Espresso coffee machine according to claim 2, wherein it comprises at least one non-return valve, positioned on the air inlet circuit downstream of the heating element, said non-return valve preventing the backflow into the air inlet circuit of liquids from the brewing chamber.

4. Espresso coffee machine according to claim 1, wherein the secondary boiler of each dispensing group is provided with at least one heating element controlled by the electronic control unit to keep the water for dispensing coffee at said predetermined temperature value.

5. Espresso coffee machine according to claim 1, wherein said main water inlet circuit comprises at least one non-return valve, arranged upstream of the pump.

6. Espresso coffee machine according to claim 5, wherein said main water inlet circuit comprises at least one pressure reducing device, arranged downstream of the non-return valve and upstream of the pump.

7. Espresso coffee machine according to claim 1, wherein said main water inlet circuit comprises at least one flow meter, arranged downstream of the pump.

8. Espresso coffee machine according to claim 1, wherein said main water inlet circuit comprises at least one throttling nozzle, arranged downstream of the pump, said throttling nozzle calibrating the maximum flow rate of water entering into a respective dispensing group through said dispensing valve.

9. Espresso coffee machine according to claim 8, wherein the dispensing valve is a 3-way solenoid valve that, in the deactivation step, puts the brewing chamber in communication with a duct at atmospheric pressure, so as to discharge the residual overpressure of the brewing chamber that is generated at the end of the dispensing of the beverage.

10. Espresso coffee machine according to claim 1, wherein the secondary boiler of each dispensing group is hydraulically connected to a mechanical overpressure safety valve, configured to activate in the case in which, due to the heating of the water with consequent increase in volume, there is a pressure increase that goes beyond a predetermined maximum pressure value.

11. Process for pre-brewing and extracting coffee in an espresso coffee machine according to claim 1, the process comprising the steps of: activating the dispensing valve for introducing hot water at a constant pressure into the brewing chamber of at least one dispensing group; simultaneously activating both the compressor and the heating element for injecting hot air at preset pressure and temperature values into said brewing chamber; pre-brewing, by introducing the hot water and air mixture at preset pressure and temperature into the coffee layer for a desired time interval that is controlled by the electronic control unit; controlling in real time the air flow through the controlled modulation of the speed of the compressor, so as to obtain, in a same pre-brewing time interval, different water/air mixing ratios; and brewing at high pressure by activating the pump and de-activating the compressor and the related heating element.

12. Process according to claim 11, wherein the step for controlling in real time the air flow is carried out through a manual control by an operator.

13. Process according to claim 11, wherein it comprises a step of storing inside the electronic control unit a set of predetermined flow rate values of the pre-brewing air flow that the espresso coffee machine is capable of reproducing autonomously when the beverage dispensing command is activated.

14. Process according to claim 11, wherein it comprises a self-learning step, by the electronic control unit, of one or more air flow rate values set manually by an operator, said one or more air flow rate values being stored automatically within a set of predetermined flow rate values so that each predetermined flow rate value can then be reproduced automatically and repetitively by the espresso coffee machine.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0019] The characteristics and advantages of an espresso coffee machine according to the present disclosure shall become clearer from the following exemplifying and non-limiting description, with reference to the appended schematic drawings, in which the only FIGURE schematically shows the hydraulic and electronic circuits of such espresso coffee machine.

DETAILED DESCRIPTION

[0020] With reference to the FIGURE, the hydraulic and electronic circuits, as well as the main components, of the espresso coffee machine according to the present disclosure, are shown. The espresso coffee machine comprises at least one dispensing group 10, provided for producing the coffee and physically and functionally independent from a main boiler 12, provided for producing hot water and steam.

[0021] The temperature control of the water for producing the coffee is performed according to a known way, described for example in IT 1131532. In practice, each dispensing group 10 is physically and hydraulically connected to a small secondary boiler 14 provided to keep the water for dispensing coffee at a predetermined temperature value, considered suitable for making the beverage. Such predetermined temperature value is obtained through the controlled activation of at least one heating element 16, belonging to the secondary boiler 14 of each dispensing group 10 and appropriately controlled by an electronic control unit 18 of the espresso coffee machine. The electronic control unit 18 receives an input temperature signal, identified by a temperature probe 20 provided with a sensitive element enclosed within the secondary boiler 14 of each dispensing group 10 and placed in contact with the single-phase fluid consisting of the water.

[0022] A main water inlet circuit 22 for inletting water from the water supply network is hydraulically connected to the main boiler 12, and to the secondary boiler 14 of each dispensing group 10. Along the main water inlet circuit 22 at least one non-return valve 24 and at least one pressure reducing device 26 are arranged in sequence, normally calibrated at 1 bar, which stabilizes the base operating pressure value of the hydraulic circuit and compensates for any possible pressure variations in the water coming from the water supply network. Along the main water inlet circuit 22, downstream of the pressure reducing device 26, at least one pump 28, at least one flow meter 30 and at least one throttling nozzle 32 are also arranged in sequence.

[0023] The throttling nozzle 32 calibrates the maximum flow rate of water entering into a respective dispensing group 10 through a dispensing valve 34, that in turn determines the start and the end of dispensing, making the brewing water pass from the secondary boiler 14 of each dispensing group 10 to a brewing chamber 36 of said dispensing group 10. The brewing chamber 36 of each dispensing group 10 comprises, in a known way, a water diffusion shower head, a filter containing the coffee powder and the related filter holder. The dispensing valve 34 is typically a 3-way solenoid valve that, in the deactivation step, puts the brewing chamber 36 in communication with a duct at atmospheric pressure, so as to discharge the residual overpressure of the brewing chamber 36 that is generated at the end of the dispensing of the beverage.

[0024] The secondary boiler 14 of each dispensing group 10 is hydraulically connected to a mechanical overpressure safety valve 38, configured to activate in the case in which, due to the heating of the water with consequent increase in volume, there is a pressure increase that goes beyond a predetermined maximum pressure value, i.e. the maximum operating value of the hydraulic circuit intended for producing the espresso coffee. Typically this maximum pressure value must not exceed 13 bar.

[0025] According to the disclosure, the espresso coffee machine comprises an air inlet circuit 40, hydraulically connected to each dispensing group 10 and, more precisely, to the respective brewing chamber 36. The air inlet circuit 40 is provided with at least one compressor 42, electronically controlled by the electronic control unit 18 and configured for injecting air at a predetermined pressure value into the brewing chamber 36 of each dispensing group 10. The air inlet circuit 40 is further provided with at least one heating element 44, also electronically controlled by the electronic control unit 18 and configured for injecting air at a predetermined temperature value into the brewing chamber 36 of each dispensing group 10.

[0026] The compressor 42 is controlled by the electronic control unit 18 to work at variable speed and is positioned on the air inlet circuit 40 upstream of the heating element 44. In turn, the heating element 44 is preferably of a finned bare-wire type.

[0027] The air sucked by the compressor 42, pushed into the brewing chamber 36 of each dispensing group 10 through the heating element 44, is preferably filtered through at least one filter 46 placed on the air inlet circuit 40 upstream of the compressor 42. The air, at this point heated by the heating element 44, reaches the brewing chamber 36 passing through at least one non-return valve 48, placed on the air inlet circuit 40 downstream of the heating element 44. The function of the non-return valve 48 is to prevent the return of liquids from the brewing chamber 36 into the air inlet circuit 40.

[0028] The pre-brewing process with inflow of pressurized air, carried out by the espresso coffee machine described above, therefore involves the electronic control unit 18, the dispensing valve 34, the compressor 42 and the heating element 44. More specifically, when dispensing the beverage is required, and in particular in the first pre-brewing step which causes the coffee panel to be wetted, the dispensing valve 34 is activated.

[0029] At this point, the hot water present in the secondary boiler 14 of each dispensing group 10, pushed by the water supply at a pressure of 1 bar kept constant through the pressure reducer 26, passes through the throttle nozzle 32 and the dispensing valve 34 to reach the brewing chamber 36 of such a dispensing group 10. At the same time, both the compressor 42 and the heating element 44 are activated by the electronic control unit 18, in order to inject hot air into the brewing chamber 36 at the correct pressure and temperature for optimum preparation of the beverage.

[0030] The hot water mixture, enriched by hot air at low pressure, comes into contact with the coffee panel and completes the pre-brewing process for a desired period of time controlled by the electronic control unit 18. At the end of the pre-brewing interval, with a typical duration of 3-6 seconds, the high pressure brewing process begins, which occurs by activating the pump 28 and thus deactivating the compressor 42 and the relative heating element 44.

[0031] It is therefore possible to control in real time the air flow through the controlled modulation of the speed of the compressor 42, so as to obtain, in a same pre-brewing time interval, different water/air mixing ratios. This determines different types of emulsion of the beverage. This control also has the advantage of being able to vary the temperature of the hot pre-brewing air, due to the different heat exchange between the air flow and the heating element 44 due to the variation of flow rate that can be modulated through the compressor 42. This is a further element of flexibility of the type of emulsion obtainable from this process.

[0032] Based on a first operating mode of the espresso coffee machine, the air flow variation can take place through a manual control by an operator. By using a control device (not shown), functionally connected to the electronic control unit 18, the operator can increase or reduce the air flow quantity by acting on the speed of the compressor 42.

[0033] A second operating mode of the espresso coffee machine envisages storing, inside the electronic control unit 18, a set of predetermined flow rate values of the pre-brewing air flow that the espresso coffee machine is capable of reproducing autonomously with the simple activation of the beverage dispensing command. The different air flow values correspond to different levels of emulsion.

[0034] A third operating mode of the espresso coffee machine finally envisages a self-learning step, by the electronic control unit 18, of one or more flow rate values set manually by the operator, which are stored automatically within the set of predetermined flow rate values so that each predetermined flow rate value can then be reproduced automatically and repetitively by the espresso coffee machine.

[0035] Thus, it has been seen that the espresso coffee machine according to the present disclosure achieves the aim and objects set forth above.

[0036] The espresso coffee machine according to the present disclosure thus conceived is susceptible to many modifications and variants, all falling within the same inventive concept; furthermore, all the details can be replaced by technically equivalent elements. In practice, the materials used as well as shapes and dimensions, may be any, according to technical requirements.

[0037] The protective scope of the disclosure is therefore defined by the appended claims.