Espresso coffee machine with pre-infusion device and method for dispensing espresso coffee

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] Espresso coffee machine with pre-infusion device and method for dispensing espresso coffee

[0002] TECHNICAL SECTOR

[0003] The present invention relates, in general, to the sector of espresso coffee machines. More particularly, it relates to the pre-infusion phase in espresso coffee machines.

[0004] Even more particularly, the present invention relates to an espresso coffee machine with a pre-infusion device and a method for dispensing espresso coffee.

[0005] PRIOR ART

[0006] The conventional techniqueforextracting espresso coffee involves the entry of water into filter chamber in which the ground coffee is present. The water is introduced into the coffee by means of a pressure thrust which is generated either by means of a pump with an electric motor or by a mechanical -action pressure system (lever / piston / spring).

[0007] When the hot water reaches the coffee puck, a few problems may arise, these being mainly due to the speed of the flow and the sudden increase in pressure, which may result in a non-optimum extraction of the organic substances in the coffee.

[0008] Over time a number of so-called pre-infusion systems have been developed. The purpose of these systems is to introduce initially a smaller quantity of water inside the infusion chamber, at a lower pressure or lower flowrate. This operation ensures a more uniform distribution of water over all the ground coffee and avoids sudden increases in pressure and flowrate which occurs when there is no pre-infusion system. The result of this operation is a more homogeneous extraction which creates a more pleasanttaste and tactile sensation on the palate, avoiding also the formation of channels in the coffee puck or cracking of the coffee puck which in any case result in non -uniform water flow passages.

[0009] Various pre-infusion systems are known.

[0010] According to a first known technique, dispensing is interrupted after a very short period of time, i.e. about one second, and then the initial dispensing is started again.

[0011] A second pre-infusion system is known from EP2299878 and involves introducing water very gradually into the pre-infusion chamber. This gradual supply is realized by using mechanical flow-restriction valves.

[0012] A third known pre-infusion system involves establishing pressure profiles which are managed electronically.

[0013] WO20221 62705 describes a system for the production of a coffee beverage with a plurality of temperatures and flowrates. Water supplied from two separate circuits is mixed together.

[0014] US2020170441 describes a coffee machine with a proportional pre-infusion system.

[0015] SUMMARY OF THE INVENTION

[0016] The Applicant has studied the known solutions for providing a pre-infusion function in an espresso coffee machine.

[0017] The Applicant has noted that the aforementioned first solution has at least two drawbacks: the first drawback is that it cannot be performed for a set manageable time and risks losing all the advantages during pressurized dispensing; the second drawback is that resulting from the discharge of part of the liquid containing extracted substances and therefore a reduction in the quality of the extracted coffee.

[0018] The Applicant has noted that the second solution can also be improved because it may be difficult to find the manual adjustment point for achieving the reduced flow for generating the correct infusion.

[0019] The Applicanthas noted that the third solution is efficient, but in any case relatively complex and costly to realize.

[0020] The Applicant has defined the aim of providing a pre-infusion system in which the user has the possibility of setting the amount of water to be introduced inside the extraction chamber.

[0021] The Applicant has defined the aim of providing a pre-infusion system in which the user has the possibility of deciding the duration of the pre-infusion phase.

[0022] The Applicant has defined the aim of providing a pre-infusion system in which the machine does not eliminate by means of draining any quantity of water which has already come into contact with the coffee.

[0023] The aforementioned objects are achieved at least partially by an espresso coffee machine with two solenoid valves arranged in sequence.

[0024] With thecombined opening arrangementof the solenoid valves it is possible to introduce water inside the infusion chamber, waitfor a period of time which can be set by the user, until the water comes into contact with thewhole of the coffee puck, and recommence dispensing using the classical method.

[0025] According to a first aspect, the present invention provides an espresso coffee machine comprising a coffee boiler configured to contain water, a dispensing group and a hydraulic circuit between the coffee boiler and the dispensing group, wherein the dispensing group comprises an engaging memberfor releasably engagingafilterholderwhich holdsafilterwith a coffee powder puck, wherein the hydraulic circuit comprises a first two-way solenoid valve an da second three-way solenoidvalvewhich isarranged in thehydraulic circuit downstream of the first solenoid valve. Advantageously, the hydraulic circuit may also comprise a hydraulic connection duct.

[0026] Accordingto embodiments, th e first solenoidvalveand the second solenoid valve can be operated independently so as to open or close a port of the first and second solenoid valves.

[0027] According to embodiments, the first solenoid valve is not, or does not comprise, a proportional valve. The first solenoid valve is an on / off nonproportional valve.

[0028] According to embodiments, the first solenoid valve comprises a first inlet port and a second outlet port and wherein the second solenoid valve is a solenoid valve comprising a first inlet port, a second outlet port and a third discharge port.

[0029] According to embodiments, during a phase of filling the infusion chamber, the first port and the second port of the first solenoid valve are open and in fluid communication and wherein the first port and the second port of the second solenoid valve are open and in fluid communication, so that the water flows from the coffee boiler to the filter. According to embodiments, during a pre-infusion phase, the first solenoid valve is kept closed and the second solenoid value is kept open, so that the water flows and wets the coffee puck in the filter.

[0030] According to embodiments, during an extraction or dispensing phase, the first port and the second port of the first solenoid valve are in fluid communication and the first port and the second port of the second solenoid valve are in fluid communication, so that the water flows from the first solenoid valve to the second solenoid valve and then to the coffee puck in the filter.

[0031] According to embodiments, during a phase following the extraction or dispensing phase, the first port and the second port of the first solenoid valve are not in communication with each other, the first port and the second port of the second solenoid valve are not communication with each other, and the third port of the second solenoid valve is open in a draining configuration for discharging the residual water.

[0032] According to another aspect, a method in an espresso coffee machine is provided for carrying out a pre-infusion phase and a subsequent extraction or dispensing phase, wherein the espresso coffee machine comprises a coffee boiler configured to contain water, a dispensing group and a hydraulic circuit between the coffee boiler and the dispensing group, wherein the dispensing group comprises an engaging member for releasably engaging a filter holder which holds a filter with a coffee powder puck, the method comprising: providing a first two-way solenoid value and a second three-way solenoid valve which is arranged in the hydrauliccircuitdownstream of the first solenoid valve; carrying out a first phase of filling the infusion chamber at least in an empty space above the coffeepuckby keepingthefirstsolenoidvalveandthe second solenoid valve open; and carrying out a pre-infusion phase by closing the first solenoid valve.

[0033] According to embodiments, the pre-infusion phase is followed by a dispensing or extraction phase in which the first and second solenoid valves are set open.

[0034] According to embodiments, the dispensing or extraction phase is followed by a draining phase for discharging the residual water, wherein during the draining phase the first and the second solenoid valves are set closed and one discharge outlet of the second solenoid valve is set open.

[0035] According to embodiments, the first solenoid valve is not, or does not comprise, a proportional valve. The first solenoid valve is an on / off nonproportional valve.

[0036] According to embodiments, the first phase of filling the infusion chamber is carried for a predetermined time period, for example about 1 second (or less), about 1 .5 seconds or about 2 seconds (or longer).

[0037] BRIEF DESCRIPTION OF THE FIGURES

[0038] The present invention will become clear from the following description, provided purely by way of a non -limiting example, to be read with reference to the accompanying drawings, in which:

[0039] - Fig. 1 is an espresso coffee machine which could incorporate the preinfusion device according to the present invention;

[0040] - Fig. 2 shows a dispensing group with coffee boiler and the pre-infusion device according to the present invention;

[0041] - Fig. 3 is a cross-sectional view of the dispensing group shown in Fig. 2, and Fig. 3A is a cross-section performed along the line A-A of Fig. 3;

[0042] - Fig. 4A, Fig. 4B, Fig. 4C, Fig. 4D and Fig. 4E show, in simplified form, some of the operating phases of the solenoid valves; and

[0043] - Fig. 5 is a cross-section which shows the entry of the water during the pre-infusion phase.

[0044] DETAILED DESCRIPTION

[0045] Fig. 1 shows, merely by way of example, an espresso coffee machine 1 which may incorporate the present invention. The machine 1 typically comprises a machine body 2 which contains all the main components. The machine body 2 is box-shaped and may comprise panels made of sheet metal or the like. The machine 1 comprises a dispensing group GR configured for the engagement, in a releasable manner, of a filterholderPF (shown in Figures 2 and 3)

[0046] The machine 1 may comprise control devices, for example one or two handles 3 and a lever LV or pushbutton or switch for starting and ending the dispensing (or extraction) of the coffee.

[0047] The machine 1 may also comprise a display 4 for showing some operating parameters.

[0048] The machine 1 may also comprise one or more dials 5 for showing, for example, pressure or temperature values.

[0049] The machine 1 may also comprise a steam wand 6 for dispensing steam used, for example, to foam milk or the like.

[0050] The dispensing group GR may be provided underneath with a drip tray 7 and a grille on which a cup can be placed during dispensing of the espresso coffee.

[0051] The filter holder PF comprises a body PF-B and a handle PF-H. The body, in turn, is configured to hold a filter FL in which a puck FP of coffee powder is formed.

[0052] The filter FL has a substantially cup-shaped form with a bottom provided with a plurality of holes or openings.

[0053] The machine 1 may comprise, internally, a steam boiler and a coffee boiler CB.

[0054] Fig. 2 shows, by way of example, a dispensing group GR with a coffee boiler CB. A filter holderPF is mounted releasably on the dispensing group GR, as shown in the cross-section of Fig. 3.

[0055] The pressurized water, which may be pre-heated, is introduced into the coffee boiler CB. It is heated to the temperature of use and is directed towards coffee powder puck CP (typically pressed) in the filter FL. In embodiments, the water entering the coffee boiler may be pre-heated in a pre-heater which uses the heat of the water present in the steam boiler.

[0056] According to the present invention, a first solenoid valve EV1 and a second solenoid valve EV2 are provided along a hydraulic circuit HC between the coffee boiler CB and the filter FL, downstream of the first solenoid valve EV1 , and operate as schematically illustrated in the various Figures 4A, 4B, 4C and 4D. The first solenoid valve EV1 may be of the two-way type, with a first inlet port and a second outlet port. The first solenoid valve may be of the on / off type. The first solenoid valve may be of the non -proportional type.

[0057] The second solenoid valve EV2 may of the three-way type so as to allow discharging of the water at the end of dispensing. The second solenoid valve EV2 comprises a first in let port, a second outlet port and a third discharge port.

[0058] Fig. 4A shows the standby and draining phase where the system and the solenoid valves are at the end of a dispensing operation. During this phase, the first solenoid valve EV1 and the second solenoid valve EV2 are closed. In th is way, the pressurized hot water stops flowing outfrom the coffee boiler CB. The discharge outlet of the second solenoid valve EV2 (the third port of EV2) is open so as to discharge the residual waterwhich is still present in the circuit and in the infusion chamber.

[0059] Fig. 4B shows the phase where filling of the water for pre-infusion is performed. During this phase, there takes place the simultaneous opening of the first solenoid valve EV1 (the first port and the second port are in communication with each other) and the second solenoid valve EV2 (the first port and the second port are in communication with each other).

[0060] This phase results in the wetting of the coffee puck with water by gradually filling the infusion chamber IC (Fig. 5) and the circuit part situated between the secondsolenoidvalve andthe infusion chamberlC. For as long as the infusion chamber and the aforementioned circuit part are not completely filled the pressure does not increase. The expression “infusion chamber” comprises the free space between the upper surface of the coffee puck and the shower screen from which the water flows out for extraction of the coffee.

[0061] Fig. 4C shows the pre-infusion phase during which the first solenoid valve EV1 is closed (the first port and the second port are not in communication with each other) and the second solenoid valve EV2 is open (the first port EV2-1 and the fourth port EV2-2 are open and in communication with each other). When the first solenoid valve EV1 is closed, water does not flow out from the coffee boiler CB. In th is way, the water introduced into the infusion chamber IC during thewater filling phase (Fig.4B) remains infused with the coffee inside the coffee puck.

[0062] The duration of this phase may be determined beforehand (by the manufacturer or the user). For example, it may be in the region of one or more seconds. Alternatively, the duration of this phase may be variable. A device may be provided for detecting a variation in a value of a parameter which indicates the degree of filling of the pre-infusion chamber so that the espresso coffee dispensing phase may be started depending on the detected variation in the value of the filling parameter.

[0063] The device could comprise a volumetric meter, configured to detect slowing down of the water flow. Slowing down of the water flow indicates that the preinfusion chamber is becoming full.

[0064] The device could comprise a pressure transducer.

[0065] Fig. 4D illustrates the dispensing phase. During this phase, thefirst solenoid valve EV1 is open again (the first port and the second port are in communication with each other), allowing theflow of pressurized hot water to act on the coffee puck and continue with the extraction phase. Obviously, during the extraction phase, the second solenoid valve EV2 remains open as during the pre-infusion phase (the first port and second port are in communication with each other).

[0066] Fig. 4E shows the draining phase which may be advantageously performed at the end of dispensing. During this phase, the first solenoid valve EV1 and the second solenoid valve EV2 are closed (the first port is not in communication with the second port). In this way, the pressurized hot water stops flowing out of the coffee boiler CB. The discharge outlet of the second solenoid valve EV2 (the third port of EV2) is opened so as to discharge the residual water which is still present in the circuit and in the infusion chamber. Therefore, the water is discharged at the end of (and not before) extraction. It is not discharged at the end of pre-infusion.

Claims

CLAIMS1 . An espresso coffee mach ine (1 ) comprising a coffee boiler (CB) configured to contain water, a dispensing group (GR) and a hydraulic circuit (HC) between the coffee boiler (CB) and the dispensing group (GR), wherein the dispensing group (GR) comprises an engaging member (CM) for releasably engaging a filter holder (PF) which holds a filter (FL) with a coffee powder puck (FP), wherein the hydrauliccircuit (HC) comprises a first two-way solenoid valve (EV1 ) and a second three-way solenoid valve (EV2) which is arranged in the circuit downstream of thefirst solenoid valve (EV1 ).

2. The machine (1 ) of claim 1 , wherein thefirst solenoid valve and the second solenoid valve (EV1 , EV2) can be operated independentlytoopen or close a port of the first and second solenoid valves.

3. The machine (1 ) of claim 1 or 2, wherein the first solenoid valve (EV1 ) does not comprise a proportional valve.

4. The machine (1 ) of claim 1 , 2 or 3, wherein the first solenoid valve (EV1 ) comprises a first in let port and a second outlet port and wherein the second solenoid valve (EV2) is a solenoid valve comprising a first inlet port, a second outlet port and a third discharge port.

5. The machine (1 ) of claim 4, wherein, during a phase of filling the infusion chamber (IC), the first port and the second port of the first solenoid valve (EV1 ) are open and in fluid communication and wherein thefirst port and the second port of the second solenoid valve (EV2) are open and in fluid communication, so that water flows from the coffee boiler (CB) to the filter (FL).

6. The machine (1 ) of claim 4 or 5, wherein , during a pre-infusion phase, the first solenoid valve (EV1 ) is kept closed and the second solenoid valve (EV2) is kept open such th at the water flows and wets the coffee puck (CP) in the filter (FL).

7. The machine (1 ) of claims 4, 5 or 6, wherein , during an extraction or dispensing phase, the first port and the second port of the first solenoid valve (EV1 ) are in fluid communication and wherein thefirst port and thesecond port of the second solenoid valve (EV2) are in flu id commun ication, such th at the water flows from the first solenoid valve (EV1 ) to the second solenoid valve (EV2) and then to the coffee puck (CP) in the filter (FL).

8. The machine (1 ) of any one of claims 4-7, wherein, during a phase following the extraction or dispensing phase, the first port and the second port of the first solenoid valve (EV1 ) are not in communication with each other, the first port and second port of the second solenoid valve (EV2) are not in communication with each other and the third port of the second solenoid valve (EV2) is open in a drain ing configurationfordischargingthe residual water.

9. A method in an espresso coffee machine (1 ) for carrying out a pre-infusion phase and a subsequent extraction or dispensing phase, wherein the espresso coffee machine (1 ) comprises a coffee boiler (CB) configured to contain water, a dispensing group (GR) and a hydraulic circuit (HC) between the coffee boiler (CB) and the dispensing group (GR), wherein the dispensing group (GR) comprises an engaging memberfor engaging in releasable mannera filter holder (PF) holding a filter (FL) with a coffee powder puck (FP), the method comprising: providing a first two-way solenoid valve (EV1 ) and a second three-way solenoid valve (EV2) arranged in the hydraulic circuit downstream of the first solenoid valve (EV1 ); carrying out a first phase of filling the infusion chamber (IC) at least in an empty space above the coffee puck (CP) by keeping the first solenoid valve (EV1 ) and the second solenoid valve (EV2) open; and carrying out a pre-infusion phase by closing the first solenoid valve (EV1 ).

10. The method of claim 9, wherein the pre-infusion phase is followed by a dispensing or extraction phase in which the first and second solenoid valves (EV1 , EV2) are set open.

11. The method of claim 10, wherein the dispensing or extraction phase is followed by a draining phase for discharging the residual water, wherein during the draining phase the first and second solenoid valves (EV1 , EV2)are set closed and one discharge outlet of the second solenoid valve (EV2) is set open.

12. The method of claim 9, 10 or 11 , wherein the first solenoid valve (EV1 ) does not comprise a proportional valve.

13. The method of claims 9, 10, 11 or 12, wherein the first phase of filling the infusion chamber (IC) is carried out for a predetermined time period.