Professional espresso coffee machine

Abstract

A beverage preparation machine includes: - at least one brewing assembly for producing a beverage by brewing a brewing substance with a brewing liquid; - a brewing liquid supply line for supplying the brewing liquid to the brewing assembly; and - an electronic control unit for controlling the operation of the beverage preparation machine; the brewing assembly includes: - a brewing liquid dispenser for dispensing the brewing liquid; and - a filter holder having one or more beverage dispensing nozzles, the filter holder internally defining a brewing chamber that can be filled with a brewing substance to be brewed with the brewing liquid to prepare a beverage, and the filter holder being manually connectable to the brewing liquid dispenser to receive the brewing liquid therefrom; the brewing liquid supply line includes: - a brewing liquid flow rate regulation system for regulating the flow rate of the brewing liquid supplied to the brewing assembly; and - a brewing liquid flow meter for measuring... The electronic control unit (ECU) is configured to: - store functional data required to control the brewing liquid flow rate regulation system during the beverage preparation cycle, and, for example, allow determination of the presence of one or more predetermined characteristics of the brewing liquid flow rate supplied to the brewing assembly during the beverage preparation cycle; and - control the brewing liquid flow rate regulation system during the beverage preparation cycle based on the stored functional data and the electrical output of the brewing liquid flow rate meter to perform the steps of pre-brewing the brewing substance located in the brewing chamber with the brewing liquid, followed by the step of pressurizing the brewing chamber and the subsequent step of brewing the brewing substance located in the brewing chamber with the brewing liquid. The electronic control unit is also designed to perform the pressurized brewing chamber step by: - ​​controlling the brewing liquid flow regulation system to increase the flow rate of brewing liquid supplied to the brewing assembly; - determining, based on the electrical output of the brewing liquid flow meter, whether the flow rate of brewing liquid supplied to the brewing assembly exhibits one or more first predetermined characteristics, wherein the one or more first predetermined characteristics indicate that the brewing chamber is properly filled with brewing liquid; and - when it is determined that the flow rate of brewing liquid supplied to the brewing assembly exhibits one or more first predetermined characteristics, maintaining the brewing liquid flow regulation system in a predetermined stable operating state.

Description

[0001] Citations of relevant applications

[0002] This patent application claims priority to Italian patent applications No. 102021000007517 and No. 102021000007541, filed on March 26, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention generally relates to beverage preparation machines, and in particular to machines capable of brewing hot beverages with pressurized hot water through a brewing substance, such as coffee-based beverages (e.g., espresso, instant coffee, espresso with water, or "freshly brewed" coffee), tea-based beverages, or beverages based on barley or other grains.

[0004] The present invention finds advantageous, but not only, applications in automatic or semi-automatic professional espresso machines. For ease of description, the following description will refer to such automatic or semi-automatic professional espresso machines without losing its generality. Background Technology

[0005] Coffee is widely recognized for its immense popularity among the public and the food and beverage industry (also known as Ho.Re.Ca, an acronym for hotel, restaurant, and coffee shop). Interest in this beverage has steadily grown among consumers, and the number of drinks dedicated to its flavor and experience has multiplied, but a crisis has emerged. In fact, coffee consumption has increased from 80 million 60kg bags to 160 million 60kg bags in the past 40 years, with millennials driving this growth, even in traditional markets and less developed markets where the coffee industry is starting from scratch, such as China or the Far East.

[0006] Today, the focus in this sector is on "premiumization" (i.e., the trend of consumers buying high-priced, high-quality products) and "specialization," with espresso accounting for 10% of the value of large chain businesses.

[0007] In the field of professional espresso machines, there are different technologies used to control the coffee brewing process in order to ensure the good quality of the dispensed product.

[0008] For example, some of these technologies are described in EP1867262B1, EP2313182B1, EP2313183B1, EP2575561B1, EP2642906B1, EP2991530B1, EP3364826A1, WO2015 / 124592A1 and US2015 / 110935A1.

[0009] Specifically, WO2015 / 124592A1 discloses a coffee machine comprising: at least one hydraulic brewing circuit including at least one water supply pump; at least one water heater hydraulically cascaded to the water supply pump; at least one brewing assembly hydraulically cascaded to the water heater, such that hot water flows through the brewing assembly at a flow rate to perform a brewing cycle; means for regulating the water flow rate; means for measuring the water flow rate; and a feedback controller connected to the regulating means and the measuring means, configured to measure in real time the current value of the water flow rate measured by the measuring means and a corresponding reference value, and configured to control the regulating means to eliminate any deviation of the current value of the water flow rate from the corresponding reference value of the water flow rate.

[0010] US2015 / 110935A1 relates to regulating the flow rate in an espresso machine during a multi-stage brewing process including a pre-brewing stage and an extraction stage. During the pre-brewing stage, ground coffee is slowly pre-wetted and / or deaerated with a first volume of water delivered at a first flow rate. During the extraction stage, a second volume of water is delivered at a second flow rate to extract espresso, wherein the second volume of water is delivered at a pressure generally greater than the first volume. The second flow rate is greater than the first flow rate. The flow rate, volume, and pressure are regulated by the espresso machine, which includes a flow regulation assembly comprising a first flow path and a second flow path, and a first valve and a second valve. A barista can change the flow rate, volume, and pressure of water throughout the brewing process by opening, closing, or otherwise adjusting at least one valve.

[0011] EP2575561B1 discloses a beverage dispensing machine including a first hydraulic line comprising a water source, a first pump, a first water heating device, a brewing device selected from a brewing chamber and a capsule, the brewing device having an inlet and an outlet, and a beverage collection device for collecting brewed beverage exiting the brewing device and dispensing the beverage into a container. The beverage dispensing machine also includes a second hydraulic line comprising a second pump and a second water heating device, the outlet of which is connected to the first hydraulic line at a location downstream of the brewing device relative to the water flow in the first line. The first hydraulic line also includes means for maintaining a substantially constant pressure in the brewing device for a preset time, the pressure being less than the opening pressure of the brewing device.

[0012] The applicant has experienced that, while the professional espresso machines described in the prior art references listed above are satisfactory in many respects, there is still considerable room for improvement in the control of the coffee brewing process, which is a fundamental factor in the quality of the dispensed beverage.

[0013] Therefore, the applicant's WO2021 / 005570A1 proposes a beverage preparation machine, which includes at least: a brewing component configured to brew a beverage with a brewing liquid through a brewing substance; a brewing liquid supply line for supplying the brewing liquid to the brewing component; and an electronic control unit for controlling the operation of the beverage preparation machine.

[0014] The brewing liquid supply line includes: a brewing liquid flow regulating solenoid valve for regulating the flow rate of brewing liquid supplied to the brewing assembly; and a brewing liquid flow meter for measuring and indicating the amount of brewing liquid supplied to the brewing assembly and outputting an electrical output indicating that amount.

[0015] The electronic control unit is electrically connected to the brewing liquid flow meter to receive its electrical output and electrically connected to the brewing liquid flow regulating solenoid valve to provide it with an electrical command. It is configured to store data presenting at least a target brewing liquid flow rate curve, which indicates the time evolution of the brewing liquid flow rate intended to be supplied to the brewing assembly during the beverage preparation cycle. It also performs closed-loop control of the brewing liquid flow regulating solenoid valve based on the electrical output of the brewing liquid flow meter and the target brewing liquid flow rate curve, so that the current brewing liquid flow rate supplied to the brewing assembly follows the target brewing liquid flow rate curve. Summary of the Invention

[0016] The applicant has experienced that while the beverage preparation machine disclosed in WO2021 / 005570A1 is very satisfactory in many respects, there is still room for improvement in the control of the coffee brewing process.

[0017] Therefore, the object of the present invention is to provide a professional espresso machine that improves upon known coffee machines in terms of control over the coffee brewing process.

[0018] According to the present invention, a beverage preparation machine as claimed in the appended claims is provided. Attached Figure Description

[0019] Figure 1 , Figure 2 and Figures 7 to 11 The time curves of the physical quantities involved in beverage preparation in a professional espresso machine are shown.

[0020] Figure 3a , Figure 3b and Figure 3c The diagram schematically illustrates the pre-brewing stage, pressurization stage, and brewing stage of the beverage preparation cycle.

[0021] Figure 4 This is a 3D diagram of the applicant's professional espresso machine.

[0022] Figure 5 , Figure 6a and Figure 6b schematically shown Figure 4 The professional espresso machine shown has different hydraulic circuits and electronic control structures. Detailed Implementation

[0023] The invention will now be described in detail with reference to the accompanying drawings to enable those skilled in the art to implement and use it. Various modifications to the described embodiments will be apparent to those skilled in the art, and the general principles described can be applied to other embodiments and applications without departing from the scope of protection of the invention as defined in the appended claims. Therefore, the invention should not be considered limited to the described and illustrated embodiments, but is given the widest possible scope of protection according to the described and claimed features.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly used by one of ordinary skill in the art to which this invention pertains. In the event of conflict, the definitions provided herein shall be binding. Furthermore, these embodiments are provided for illustrative purposes only and should not be considered limiting.

[0025] Specifically, the block diagrams in the accompanying drawings and described below should not be construed as representations of structural features (i.e., construction limitations), but rather as representations of functional features (i.e., inherent characteristics of the device), and are defined by the effects obtained (i.e., functional limitations), which can be achieved in different ways in order to protect their function (operational possibilities).

[0026] To facilitate understanding of the embodiments described herein, reference will be made to specific embodiments, and specific terminology will be used to describe them. The terminology used in this document is intended to describe specific embodiments only and is not intended to limit the scope of the invention.

[0027] In short, the present invention relates to a technique referred to below as DFC (representing Dynamic Flow Control) for dynamically adjusting the flow rate of water supplied to the brewing components of a professional espresso machine in order to dynamically change the coffee dispensing state and thereby correspondingly change the sensory properties of the beverage in the cup.

[0028] DFC technology differs from other existing technologies based on water flow regulation because it does not apply a predetermined water flow rate during different beverage preparation steps after the pre-brewing of the brewing substance.

[0029] Specifically, the DFC technology stems from the applicant's observation that there is no ideal water flow rate that corresponds to all coffees: in fact, it is almost impossible to obtain two identical dispensing results from two coffee capsules, even if they are very similar, while maintaining the same water flow rate throughout the entire beverage preparation cycle. Furthermore, attempts are made to minimize as many of the variables involved as possible that may alter the preparation conditions, variables that cannot be completely eliminated.

[0030] The particle size of the ground coffee, the amount of ground coffee, the distribution of the coffee powder, the compression force within the filter holder (whether obtained manually or with a pressure press), and the uniformity of compression are all variables that even the most professional baristas cannot fully control using the best available equipment. Under these variable conditions, applying a predetermined water flow rate throughout the beverage preparation cycle can be counterproductive.

[0031] Let's consider a scenario where, after the coffee grinder has been calibrated, it has been found that the flow rate Q of water supplied to the brewing unit during espresso preparation is a definite function of time Q(t) or the volume of water dispensed Q(v), or even considered a constant Q(t) = K or Q(v) = K starting from a certain point in the beverage preparation. Therefore, Q can generally be defined as the flow rate of water that ensures the beverage in the cup meets the requirements of the dispensed coffee (flavor, texture, creaminess).

[0032] Existing technologies on the market attempt to regulate water flow to precisely reproduce the Q function, thereby imposing predetermined operating conditions without considering that the variables involved would make the beverage in the cup extremely unstable.

[0033] However, the applicant has experienced that the pressure inside the filter holder can vary significantly if, for example, the compressed coffee capsule in the filter holder contains a fraction of a gram less than the nominal amount (grinder error), or if it is not properly compressed (human error), or if the ground coffee has different characteristics in terms of moisture, particle size, composition, etc., while maintaining the same flow rate Q(t) or Q(v). Coffee capsules that tend to "give way" (e.g., due to channeling effects, or because the coffee is overripe and rapidly "wears out") offer less resistance to water flow, and the regulating system operates by braking the water flow, which would naturally tend to increase, in order to maintain the predetermined function Q(t) or Q(v). This can drastically reduce the water pressure during preparation to values ​​completely outside the desired range, which guarantees optimal extraction.

[0034] To demonstrate this phenomenon, Figure 1 An example is shown in the graphs displaying them:

[0035] -Curve (1): It is a typical optimal water flow curve, defined by the user, and it will be reproduced by a conventional water flow regulation system for all coffees dispensed with this specific predetermined characteristic;

[0036] -Curve (2): It is the pressure of the water supplied to the brewing components under the optimal condition Q(t), which will ensure that the coffee extract reflects sensory requirements;

[0037] - Curve (3): It is the “natural” water flow that will cause the coffee capsule to pass through at a constant water pressure under the constant water pressure given by the bypass of the water pump, as happens in most coffee machines with a single water pump.

[0038] -Curve (4): It is the water pressure that will occur naturally if the water flow regulation does not intervene.

[0039] -Curve (5): It is the water pressure generated after adjusting the water flow rate.

[0040] As can be understood by analyzing the graphs, because the coffee capsule has less resistance to water flow and forces the water flow regulation system to intervene by reducing the water flow rate, the water pressure (curve (5)) tends to drop significantly at the end of the beverage preparation cycle. Although it has the same water flow rate Q(t) as the optimal case, this beverage preparation cycle results in water pressure (and therefore the beverage in the cup) that is completely different from what is expected.

[0041] While simple water flow control techniques can accurately reproduce the flow rate curve Q(t) under optimal conditions, water pressure in various beverage preparation processes can vary significantly from these optimal conditions. This is because, as described, the resistance of the coffee capsule to water flow varies in a completely unpredictable manner throughout the beverage preparation cycle, depending not only on the characteristics of the coffee (grinding, compression, mixing, etc.) but also on the pressure of the water supplied to the brewing components.

[0042] In summary, in order to keep the water flow rate Q(t) at the set value, the adjustment of the water flow rate inevitably affects the pressure of the water supplied to the brewing components, which in turn impairs the reproducibility of the beverage in the cup.

[0043] Therefore, the applicant has experienced that it is preferable to operate with a fixed water pressure, rather than any type of water pressure regulation, to ensure that the beverage in the cup is as close to optimal as possible, rather than perfectly replicating the water flow curve Q(t) and thus completely losing control over the water pressure. In fact, conventional professional coffee machines without any regulation system can maintain good repeatability of the beverage in the cup with certain tolerances in terms of both water pressure and water flow, even when many variables are involved. This is because, structurally, through the bypass of the water pump, conventional professional coffee machines eliminate the variable represented by water pressure, keeping it almost constant, which is very important for the results in the cup.

[0044] Furthermore, in recent years, the market has been observed to be moving towards solutions that allow users to customize their beverage servings, and towards greater flexibility aimed at enhancing certain coffee characteristics or concealing any potential defects. Customizing the servings requires the ability to control measurable physical quantities during coffee preparation, such as water pressure, temperature, and flow rate.

[0045] Regarding water flow control, as mentioned above, the main problem is that water flow control alone cannot guarantee the repeatability of coffee extraction. This is because the total loss in controlling the water pressure supplied to the brewing components leads to significant variations in the final result within the cup. It is necessary to enable users to even customize the reference distribution of the water flow that the system must reproduce in order to generate water flow rates Q1(t), Q2(t)...Q n The need for different reference distributions of (t) can lead to completely uncontrollable in-cup results, thus deviating from the main market requirements: customization and repeatability.

[0046] DFC (Digital Flow Control) technology aims to address customization and repeatability by intervening with a limited number of parameters and dynamically controlling the water flow to adapt the water distribution to the state of the coffee capsule. In fact, DFC technology does not define a correct water flow (which, given the numerous variables involved, practically doesn't exist), but rather defines an extraction pattern.

[0047] In fact, DFC technology gives users the ability to prepare beverages according to predetermined standards, allowing them to freely change its characteristics and choose whether to maintain a constant water flow rate at specific beverage preparation steps. In this way, the system can adapt to the variables involved, and in cases where a constant water flow rate is required, this is not predetermined by the user, because, as can be seen, there is no such thing as an ideal water flow rate; rather, it is calculated in real time by the system at specific moments during beverage preparation.

[0048] In traditional professional coffee machines, pre-brewing and water pressure variations are not considered. Furthermore, because the hydraulic characteristics of the water supply line remain constant, the water flow rate is determined solely by the state of the coffee capsule in the filter holder. In essence, traditional professional coffee machines offer only one method of coffee extraction: a fixed pre-brewing time and constant water pressure, both in terms of duration and water flow rate.

[0049] DFC technology falls into this category, but it has the potential to change the way beverages are prepared, playing a role in its three main steps: pre-brewing, pressurization, and brewing.

[0050] Figure 2 The common time distribution of water pressure (curve (6)) and water flow rate (curve (7)) in traditional professional coffee machines is shown.

[0051] exist Figure 2In the text, the three main beverage preparation steps are further identified using frames:

[0052] - Pre-brewing (left-hand frame): Water supplied to the filter holder seeps from the nozzle under low pressure and begins to wet the top layer of the coffee capsule. The water flow rate is almost constant and depends entirely on the hydraulic pressure characteristics of the water supply line;

[0053] - Pressurization (Center Frame): Water has filled the space between the coffee capsule and the nozzle, and resistance is found within the capsule as it wets and expands within the filter holder. Water pressure in the brewing chamber increases and the water flow reaches its peak. Then, as the volume between the nozzle and the filter holder becomes completely filled with the brewed beverage, the water flow begins to decrease. The water flow then reaches its lowest level (due to the fully filled brewing chamber, the release of carbon dioxide, and the formation of cream), and the water pressure reaches its highest level. From this point on, the beverage exits the filter holder and is dispensed into the cup. In traditional espresso machines, the water pump operates at a constant pressure, and pressurization always occurs at the same rate.

[0054] - Brewing (right-hand frame): Coffee flows from the filter holder and into the cup; the water flow increases slightly after reaching the minimum level necessary for pressurization; the coffee capsule tends to wear down, altering the resistance opposite to the water flow until the beverage preparation process is complete. In traditional espresso machines, the water pressure is constant, while the water flow depends solely on the state of the wet coffee capsule at that point.

[0055] DFC technology allows for the alteration of the three beverage preparation steps by applying several common parameters to the three steps:

[0056] -Pre-brewing:

[0057] √ Initial wetting flow

[0058] √Duration

[0059] -Pressure:

[0060] √Pressure application rate (slope of the pressure-adjusted bend)

[0061] - Brewing:

[0062] √ Stable flow brewing

[0063] √ Free flow brewing

[0064] After defining the beverage preparation mode, a combination of user-modifiable parameters is used, and the water pressure has been set via a bypass of the water pump, ensuring that the beverage in the cup will have repeatability exactly like that of a traditional espresso machine.

[0065] The following will refer to Figure 4The professional espresso machine shown Figure 5 The flowchart shown discusses the three beverage preparation steps mentioned above in detail.

[0066] like Figure 4 and Figure 5 As shown, the professional espresso machine, generally indicated by reference numeral 1 in the attached figure, includes:

[0067] - One or more brewing components 2, configured to perform a similar brewing process to brew a brewing substance (considered in the form of pressurized hot water in the embodiment) with a brewing liquid (considered in the form of coffee powder in the embodiment) in order to produce a similar coffee-based beverage in the same or different amounts, considered in the form of espresso, such as coffee or espresso with water, wherein the coffee powder is of any same or different type in terms of coffee type (Arabic coffee, Robusta coffee), coffee blend, coffee particle size determination, coffee undergoing processes (e.g., decaffeination, flavoring, etc.);

[0068] - Water supply line 3 is used to supply pressurized hot water necessary for brewing espresso to brewing unit 2;

[0069] - User interface 4, corresponding to each brewing component 2, to allow the user to select the beverage; and

[0070] - Electronic control unit 5, used to control the operation of professional espresso machine 1 in response to beverage user selection.

[0071] Each brewing component 2 includes:

[0072] - A pressurized hot water distributor 6, in the form of a shower head or sprayer; and

[0073] - Filter holder 7, having one or more espresso dispensers 8, and adapted to hold coffee grounds in use, which will be brewed with pressurized hot water to prepare espresso, and adapted to be manually connected in use to a pressurized hot water dispenser 6 to receive pressurized hot water from it.

[0074] Water supply line 3 includes:

[0075] - Pump 9, conveniently an electric variable-speed pump, and considered common to all brewing components 2 in a non-limiting embodiment, can supply cold water from a cold water source (not shown), which can alternatively be a common water supply main or a water tank, which can be housed inside or outside the professional espresso machine 1 and fluidly connected to it and fluidly connected to the common water supply main to receive cold water from it, and is operable to supply pressurized cold water; and

[0076] - A water supply branch 10 for each brewing component 2 is arranged downstream of the water pump 9 and fluidly connected between the delivery section of the water pump 9 and the corresponding brewing component 2 to supply pressurized hot water to the corresponding brewing component 2.

[0077] Optionally, the water supply line 3 may include a water preheater (not shown), which is conveniently a continuous flow preheater, arranged downstream of the water pump 9 and located between the water pump and the water supply branch 10, to preheat the water supplied to the water supply branch.

[0078] Each water supply branch 10 includes, in the direction of water flow from the water pump 9 to the corresponding brewing component 2, the following:

[0079] - A water flow regulating solenoid valve 11, and optionally, a pressure regulator 12 disposed upstream of the water flow regulating solenoid valve 11, to regulate the water flow in the water supply branch 10; and

[0080] - Water flow meter 13, for measuring and outputting an electrical output indicating the volume of water supplied to water supply branch 10; and

[0081] - Water heater 14, for (further) heating the water in the water supply branch 10.

[0082] In a preferred embodiment, the water flow regulating solenoid valve 11 is a motorized solenoid valve with a stepper motor to allow discontinuous regulation of the water flow.

[0083] In different implementations, the water flow regulating solenoid valve 11 is a motorized solenoid valve utilizing a stepper motor to allow substantially continuous regulation of the water flow.

[0084] The electronic control unit 5 is electrically connected to the water flow meter 13 to receive from it an electrical signal indicating the water flow in the corresponding inlet branch 10, electrically connected to the user interface 4 to receive from it an electrical signal indicating beverage selection, and electrically connected to the water pump 9, electrically connected to the water flow regulating solenoid valve 11, electrically connected to the water heater 14, and, if provided, electrically connected to the water preheater to provide electrical control signals to it.

[0085] Electronic control unit 5 is programmed as follows:

[0086] -Storing functional data required to control each water flow regulating solenoid valve 11 during the beverage preparation cycle, and for example allowing the determination of the occurrence of one or more predetermined characteristics of the water flow supplied to the corresponding brewing component 2 during the beverage preparation cycle;

[0087] - Based on the stored functional data and the electrical output of the associated water flow meter 13, each water flow regulating solenoid valve 11 is controlled during the beverage preparation cycle to perform the step of pre-brewing the brewing substance located in the brewing chamber with water, followed by the step of pressurizing the brewing chamber and the subsequent step of brewing the brewing substance located in the brewing chamber with water.

[0088] In different implementations Figure 4 The professional espresso machine shown may have different water flow regulation structures or systems, and its simplified block diagram is shown in Figure 6a As shown in the image. In order to... Figure 5 Comparison, Figure 6b It also shows Figure 5 The water flow regulation structure shown is, but in accordance with... Figure 6a The same simplified form.

[0089] If it is understandable, in Figure 5 and Figure 6b The water flow regulation structure shown provides a single water pump shared by all brewing components, which has a stable delivery pressure via a bypass route, as in a conventional coffee machine, and each water supply branch has a water flow meter and a conventional motorized proportional solenoid valve, which changes the water flow segment, increases the local pressure drop, and thus changes the water flow rate.

[0090] exist Figure 6a In the illustrated water flow regulation structure, a water pump is provided for each brewing component, and the water flow rate is regulated by adjusting the rotational speed of the water pump. When a gear-driven water pump is used, for example, the delivery pressure can be increased or decreased by changing the rotational speed of the drive motor, and thus the water flow rate can be increased or decreased. In this case, even if the upstream pressure is not stable through the bypass route, the operating point of the water pump will be checked using direct or indirect methods to maintain the water distribution pressure within the expected water distribution pressure range.

[0091] Returning to the three beverage preparation steps mentioned above, the following text will refer to... Figure 6b A detailed analysis of the water flow regulation structure shown clearly demonstrates that, with necessary modifications, this... Figure 6a The water flow regulation structure shown is also effective.

[0092] 1. Pre-brewing

[0093] During the pre-brewing step, the electronic control unit 5 is programmed to appropriately control (conveniently via PID (proportional-integral-derivative) control technology) the flow rate of water supplied to each brewing component 2 by means of the electrical output of the associated water flow meter 13 and the associated water flow regulating solenoid valve 11 in a closed loop, so that the water flow regulating solenoid valve 11 introduces a local pressure drop to reduce the water flow rate to the desired value.

[0094] Specifically, the electronic control unit 5 is programmed to allow the operator to set the flow rate of water supplied to each brewing component 2 and the duration of each pre-brewing step, during which water then flows out of the nozzle at an extremely limited flow rate compared to that allowed by the hydraulic system. Without the aid of a pre-brewing chamber as in a conventional espresso machine, without encountering any resistance from the coffee capsule, the water flows out at atmospheric pressure, and the water flow rate is determined solely by the pressure drop in the hydraulic lines, with the pressure of the water supplied by the water pump 9 remaining virtually constant.

[0095] The electronic control unit 5 is also programmed to control the flow rate of water supplied to each brewing component 2 in a closed loop by following a target water flow rate curve, which indicates the time process of the expected water flow rate Q(t) supplied to the brewing component 2 during the pre-brewing step in the coffee preparation cycle.

[0096] The electronic control unit 5 is also programmed to allow the operator to program the pre-brewing water flow distribution and pre-brewing duration for each brewing component 2. Conveniently, but not necessarily, to simplify programming the pre-brewing step, the electronic control unit 5 is programmed to allow the operator to select the pre-brewing water flow rate and pre-brewing duration from different (e.g., three) constant pre-brewing water flow rates and durations stored in the electronic control unit 5, such as... Figure 7 As shown.

[0097] 2. Pressurization

[0098] As mentioned earlier, at this step, water has been added to the coffee capsule, and the brewing chamber (nozzle and filter holder) must be filled. The operator can choose how quickly water pressure is achieved in the brewing chamber, ranging from the minimum level (close to atmospheric pressure) presented in the pre-brewing step to the maximum supply pressure from the water pump.

[0099] Therefore, the electronic control unit 5 is programmed to perform open-loop control of each water flow regulating solenoid valve 11 to achieve... Figure 8 The pressurization distribution shown is without any closed-loop control of water flow.

[0100] Specifically, during the pressurization step of the brewing chamber, the electronic control unit 5 is programmed to continuously monitor the water flow based on the electrical output of the corresponding water flow meter 13, and to determine when it exhibits a predetermined characteristic indicating that one or more brewing chambers are properly filled with water.

[0101] In a preferred embodiment, the electronic control unit 5 is programmed to determine that the water flow exhibits one or more of the following predetermined characteristics: having or approaching a maximum value, starting to decrease after reaching a maximum value, and having a derivative within a predetermined range.

[0102] To achieve this, the electronic control unit 5 is programmed to calculate the change in water flow over time (discrete-time derivative) and determine when the change in water flow becomes substantially zero or within a certain range, for example, below a predetermined change threshold (±0.2 ml / s).

[0103] When the water flow exhibits one or more of the aforementioned predetermined characteristics, it means that the brewing chamber is completely filled and water passes through the filter holes, which introduces a further and significant pressure drop, causing the water flow to begin to decrease sharply, and thus the pressurization step of the brewing chamber ends.

[0104] For ease of implementation, the electronic control unit 5 is programmed to control each water flow regulating solenoid valve 11 in PWM (Pulse Width Modulation) mode, as is known. This causes the water flow regulating solenoid valve 11 to alternately close and open over time until the maximum water flow is reached. From the start of the maximum water flow until the end of the pressurization step, the water flow regulating solenoid valve 11 remains constantly open at a predetermined water flow segment, preferably the water flow segment present when the water flow exhibits one or more of the characteristics described above, so as to allow the water flow meter 13 to limit the water flow to be used during the brewing step without interference (PWM pulsation introduces reading errors).

[0105] During the pre-brewing step, in the predetermined water flow section, i.e., in the case of closed-loop controlled water flow section, the water flow regulating solenoid valve 11 remains constantly open, and the water flow gradually increases due to the change in the opposite hydraulic resistance of the brewing substance in the brewing chamber to the water flow.

[0106] In different implementations, the electronic control unit 5 can be programmed to control each water flow regulating solenoid valve 11, rather than in PWM mode, through different controls, such as according to additionally defined gradual opening and more or less complex curves, the purpose of which is always to more or less rapidly pressurize the brewing chamber, thereby giving the operator the possibility of choosing between different possibilities.

[0107] For this purpose, the electronic control unit 5 is programmed to allow the operator to program the pressurization distribution of the brewing chamber for each brewing component 2. Conveniently, but not necessarily, to simplify programming the pressurization step, the electronic control unit 5 is programmed to allow the operator to select from three PWM levels in the initial bend phase step (water flow increase), such as... Figure 9 As shown, the water flow section of the water flow regulating solenoid valve 11 maintained at the end of the pressurization step is conveniently the same in all three levels.

[0108] If possible Figure 9Understandably, the water pressure curve is approximately linear. The different curves illustrate how pressurization is achieved after pre-brewing using different bends with varying slopes; among the three different PWM levels, the higher the PWM level, the greater the slope. The water flow rates obtained for the three PWM levels indicate that; clearly, the faster the brewing chamber is pressurized, the faster the water flow rate reaches its maximum level.

[0109] 3. Brewing

[0110] The two beverage preparation steps mentioned above, namely pre-brewing and pressurization, can be defined as preparation steps because the coffee capsules are moistened and pressurized before the actual beverage is prepared and dispensed into the cup. In traditional espresso machines, this final beverage preparation step, known as brewing, typically occurs under constant water pressure, and the resulting water flow rate depends on how the coffee capsules were prepared in the previous steps and the pressure of the water pump.

[0111] Therefore, the electronic control unit 5 is programmed to allow the operator to customize the brewing process by selecting between different brewing modes, conveniently but not limited to the following two modes described below.

[0112] 3.1 Constant water pressure brewing

[0113] For the brewing step only, this brewing mode is exactly the same as conventional brewing, in which the water pump is operated to distribute water at a constant pressure defined by its bypass path. The water flow rate is allowed to increase freely, and the water flow regulating solenoid valve 11, which remains open at the predetermined water flow segment, does not interfere.

[0114] 3.2 Controlled water flow rate for rinsing

[0115] At the end of the pressurization step, as described above, the flow regulating solenoid valve 11 remains open at the predetermined water flow segment. Considering espresso, as mentioned above, there is typically a minimum water flow rate when the filter is completely filled with water and the coffee releases a significant amount of carbon dioxide to form foam. Subsequently, the coffee capsule begins to lose consistency as the water removes fats, proteins, and all substances that will constitute the beverage in the cup. Generally, there is a slight tendency for the water flow rate to increase (more pronounced in the case of freshly roasted coffee, and less noticeable in the case of very mature or old coffee).

[0116] Therefore, the electronic control unit 5 is programmed to allow the operator to select this brewing mode, wherein brewing is completed with a stable water flow rate due to the gradual and progressive closing of the water flow regulating solenoid valve 11. Starting from the water flow segment present at the end of the pressurization step, the water flow regulating solenoid valve 11 is controlled in an open loop to perform a slow closing motion to counteract the natural tendency of water flow to increase in the event of an increase in water flow: in fact, the more the water flow regulating solenoid valve 11 is closed, the more it acts as a brake, thereby introducing a load loss that tends to slow down the water flow.

[0117] Therefore, also during the brewing step, the electronic control unit 5 is programmed to continuously monitor the water flow based on the electrical output of the flow meter 13, and to determine when the water flow exhibits one or more predetermined characteristics indicating a stable water flow, in particular when the change of water flow over time (discrete-time derivative) becomes substantially zero or within a specific range of change, such as below a certain threshold of change (±0.2 ml / s).

[0118] When the water flow exhibits one or more of the above-mentioned states, especially when the water flow stabilizes at a certain value, the electronic control unit 5 is programmed to initiate closed-loop control of the water flow using PID regulation technology in an attempt to maintain the last observed value, such as... Figure 10 As shown.

[0119] Therefore, basically, since the coffee capsules of compressed coffee are always different from one another, the water flow rate stabilized by the movement of the water flow regulating solenoid valve 11 when extracting the best part of the coffee will always be different, but will be equal to the water flow rate stabilized in the first part of the brewing step.

[0120] As envisioned, for most of the brewing process, using DFC technology, the pressure of the water supplied to each brewing component 2 will be at the pressure defined by the bypass path of the water pump 9, and will tend to decrease slightly during brewing. Using water at reduced pressure instead of a constant pressure and preparing coffee at a controlled flow rate will result in variations in the beverage, such as increased sweetness and reduced bitterness and astringency, which in conventional espresso machines might be due to over-extraction of the coffee during the final portion of the brewing process at constant water pressure.

[0121] Finally, since operators unfamiliar with the trajectory of the water flow curve Q(t) may find it difficult to obtain useful information by reading such a curve, the electronic control unit 5 is programmed to display on the user interface 4 of each brewing component 2 during beverage preparation. Figure 11 The graph shown illustrates the amount of water supplied to the brewing unit 2, where the operator can easily control the gradient of water increase in the three beverage preparation steps (the water always increases cumulatively), and where the three beverage preparation steps are identified by different curves: the (PB) curve for pre-brewing, the (PR) curve for pressurization, and the (BR) curve for brewing.

[0122] Based on what has been described, the advantages that DFC technology allows for are understandable.

[0123] As mentioned earlier, the primary market demand is for the ability to customize coffee preparation while maintaining the reproducibility of the beverage in the cup. In other words, the distribution of a particular beverage preparation means the distribution of water pressure or water flow, or more generally, the distribution of quantities involved in the beverage preparation process. For the beverage preparation process to be controlled and successfully achieve a certain in-cup result, certain characteristics of the supplied coffee must be enhanced, and these characteristics must actually be present in all coffees prepared with that particular distribution.

[0124] DFC technology allows for selection of beverage preparation modes by having only a few parameters that can be changed by the operator, ensuring flexibility and repeatability.

[0125] Specifically, as with traditional espresso machines, the bypass pressure of the water pump is a fixed baseline in DFC technology. However, unlike traditional espresso machines, DFC technology allows for flexible and repeatable customization of how the bypass pressure is reached in the brewing chamber and how the coffee preparation ends. In fact, once the bypass pressure of the water pump is set, the control system is completely independent of the water pressure throughout the entire coffee preparation process, as there are no pressure sensors installed and therefore no way is the water pressure monitored.

[0126] Finally, in DFC technology, the pressure of the water supplied to each brewing component is slightly reduced during brewing, thereby increasing the sweetness of the coffee and reducing bitterness and astringency, which in conventional machines are caused by over-extraction of the coffee in the later part of the brewing process under constant water pressure.

Claims

1. A beverage preparation machine (1), comprising: - At least one brewing component (2) for producing a beverage by brewing a brewing substance with a brewing liquid; - A brewing liquid supply line (3) for supplying brewing liquid to the brewing assembly (2). as well as - Electronic control unit (5) for controlling the operation of the beverage preparation machine (1); The brewing component (2) includes: - A brewing liquid dispenser (6) for dispensing brewing liquid; and - A filter holder (7) having one or more beverage dispensing nozzles (8) internally defining a brewing chamber capable of being filled with a brewing substance, which is then brewed with a brewing liquid to prepare a beverage, and the filter holder being manually connected to the brewing liquid dispenser (6) to receive brewing liquid from the brewing liquid dispenser; The brewing liquid supply line (3) includes: - A brewing liquid flow rate regulation system for regulating the flow rate of the brewing liquid supplied to the brewing assembly (2); and - A brewing liquid flow meter (13), the amount of brewing liquid measured by the brewing liquid flow meter indicates the amount of brewing liquid supplied to the brewing assembly (2), and the brewing liquid flow meter outputs an electrical output indicating the measured amount; The electronic control unit (5) is designed to communicate with the brewing liquid flow meter (13) to receive the electrical output of the brewing liquid flow meter, and to communicate with the brewing liquid flow regulation system to provide electrical commands to the brewing liquid flow regulation system; The electronic control unit (5) is also designed to be configured as follows: - Storing functional data required to control the brewing liquid flow rate regulation system during the beverage preparation cycle, allowing determination of the presence of one or more predetermined characteristics of the brewing liquid flow rate supplied to the brewing assembly (2) during the beverage preparation cycle; and - During the beverage preparation cycle, the brewing liquid flow regulation system is controlled based on the stored functional data and the electrical output of the brewing liquid flow meter (13) to perform the step of pre-brewing the brewing substance located in the brewing chamber with the brewing liquid, followed by the step of pressurizing the brewing chamber and the subsequent step of brewing the brewing substance located in the brewing chamber with the brewing liquid. The electronic control unit (5) is characterized in that it is further designed to perform the step of pressurizing the brewing chamber in the following manner: - Control the brewing liquid flow rate regulation system to increase the flow rate of brewing liquid supplied to the brewing component (2); - Determine whether the flow rate of the brewing liquid supplied to the brewing assembly (2) exhibits one or more first predetermined characteristics based on the electrical output of the brewing liquid flow meter (13), wherein the first predetermined characteristics indicate that the brewing chamber is properly filled with brewing liquid; and - When it is determined that the flow rate of the brewing liquid supplied to the brewing component (2) exhibits one or more of the first predetermined characteristics, the brewing liquid flow rate regulation system is maintained in a predetermined stable operating state.

2. The beverage preparation machine (1) according to claim 1, wherein, The electronic control unit (5) is also designed to increase the flow rate of the brewing liquid supplied to the brewing assembly (2) during the step of pressurizing the brewing chamber by controlling the brewing liquid flow rate regulation system in an open loop.

3. The beverage preparation machine (1) according to claim 1, wherein, The one or more first predetermined characteristics are defined by the brewing liquid flow rate supplied to the brewing component (2) exhibiting one or more of the following characteristics: exhibiting or approaching a maximum value, starting to decrease after having exhibited a maximum value, and having a derivative of the brewing liquid flow rate within a predetermined range.

4. The beverage preparation machine (1) according to any one of the preceding claims, wherein, The electronic control unit (5) is also designed to: - Based on the electrical output of the brewing liquid flow meter (13), determine whether the flow rate of the brewing liquid supplied to the brewing assembly (2) exhibits one or more second predetermined characteristics indicating the presence of an appropriate state, in order to begin the step of brewing the brewing substance located in the brewing chamber with the brewing liquid; and - When it is determined that the flow rate of the brewing liquid supplied to the brewing assembly (2) exhibits one or more of the second predetermined characteristics, the brewing liquid flow rate regulation system is controlled to begin the step of brewing the brewing substance located in the brewing chamber with the brewing liquid.

5. The beverage preparation machine (1) according to claim 4, wherein, The one or more second predetermined characteristics are defined by the flow rate of the brewing liquid supplied to the brewing assembly (2), which exhibits a minimum, near minimum, or begins to stabilize at a minimum during a period of decrease after reaching a maximum value.

6. The beverage preparation machine (1) according to any one of claims 1 to 3, wherein, The electronic control unit (5) is also designed to perform the step of brewing the brewing substance located in the brewing chamber with brewing liquid by implementing a controlled brewing liquid flow brewing mode, the controlled brewing liquid flow brewing mode including: - Control the brewing liquid flow rate regulation system to counteract the natural tendency of the brewing liquid flow rate supplied to the brewing assembly (2); - Based on the electrical output of the brewing liquid flow meter (13), determine whether the brewing liquid flow rate supplied to the brewing assembly (2) exhibits one or more third predetermined characteristics indicating that the brewing liquid flow rate supplied to the brewing assembly (2) has been substantially stable; - When it is determined that the flow rate of the brewing liquid supplied to the brewing assembly (2) exhibits one or more of the third predetermined characteristics, the brewing liquid flow rate regulation system is closed-loop controlled based on the electrical output of the brewing liquid flow meter (13) to maintain a stable flow rate of the brewing liquid supplied to the brewing assembly (2).

7. The beverage preparation machine (1) according to claim 6, wherein, The electronic control unit (5) is also designed to counteract the natural tendency of the flow rate of the brewing liquid supplied to the brewing assembly (2) to increase during the step of brewing the brewing substance located in the brewing chamber with the brewing liquid by controlling the brewing liquid flow regulation system in an open loop.

8. The beverage preparation machine (1) according to claim 6, wherein, The one or more third predetermined characteristics are defined by the variation of the flow rate of the brewing liquid supplied to the brewing assembly (2) within a predetermined range.

9. The beverage preparation machine (1) according to claim 6, wherein, The electronic control unit (5) is also designed to allow the user to customize the brewing process of the brewing substance by selecting between the controlled brewing liquid flow brewing mode and the constant brewing liquid pressure brewing mode.

10. The beverage preparation machine (1) according to any one of claims 1 to 3, wherein, The brewing liquid flow regulation system includes an electronically controllable flow regulation solenoid valve (11) or an electronically controllable variable speed supply pump (9).

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