Coffee machine and extraction pressure control method thereof

Abstract

The invention belongs to the technical field of coffee machines, and particularly provides a coffee machine and an extraction pressure control method thereof. The coffee machine is configured to be capable of compressing coffee powder and brewing the compressed coffee powder. The control method comprises the following steps: determining target extraction pressure Psd of the coffee machine according to set parameters; determining the current extraction pressure Psa of the coffee machine; judging whether the current extraction pressure Psa is equal to the target extraction pressure Psd or not; and if the current extraction pressure Psa is not equal to the target extraction pressure Psd, adjusting the brewing water pressure Psb and / or the pressing force F on the coffee powder, so that the current extraction pressure Psa is equal to the target extraction pressure Psd. The brewing water pressure of the coffee machine is adjustable, and the taste of the final coffee solution is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of coffee machines, and specifically provides a coffee machine and a method for controlling extraction pressure thereof. Background Art

[0002] A coffee machine is a machine that brews and extracts coffee powder into a coffee solution. Since coffee powder is loose, hot water will more easily flow through the less dense channels and bypass the denser parts when passing through the coffee powder. This uneven water flow will lead to uneven extraction, with some coffee powder being over-extracted and tasting bitter, and some coffee powder being under-extracted and tasting light, affecting the taste of the final coffee solution.

[0003] For this reason, some coffee machines are also equipped with a compression device to compress the coffee powder into a cake shape, making the density of the coffee powder more uniform. Furthermore, during the extraction process, especially during high-pressure extraction, the cake-shaped structure with uniform density can prevent the coffee powder from shifting or being dispersed under the impact of the high-pressure water flow. In addition, the compacted coffee powder can ensure that the brewing water pressure of the water flow is evenly distributed throughout the cake-shaped coffee powder. In this way, the brewing water pressure of the water flow is crucial to the extraction of substances such as oils and flavor substances in coffee.

[0004] However, existing coffee machines usually use a constant brewing water pressure to extract coffee powder in cake form, and the extraction rate of oil, flavor substances and other substances in the coffee cannot be controlled, which affects the taste of the final coffee solution. Summary of the invention

[0005] One object of the present invention is to solve the problem that the brewing water pressure of the existing coffee machine is constant and cannot be changed, which affects the taste of the final coffee solution.

[0006] A further object of the present invention is to make the current extraction pressure of the coffee machine consistent with the target extraction pressure.

[0007] To achieve the above object, the present invention provides, in a first aspect, a method for controlling extraction pressure of a coffee machine, wherein the coffee machine is configured to compress coffee powder and brew the compressed coffee powder; the control method comprises:

[0008] Determining a target extraction pressure Psd of the coffee machine according to set parameters;

[0009] Determining a current extraction pressure Psa of the coffee machine;

[0010] Determining whether the current extraction pressure Psa is equal to the target extraction pressure Psd;

[0011] If they are not equal, adjust the brewing water pressure Psb and / or the pressing force F on the coffee powder to make the current extraction pressure Psa equal to the target extraction pressure Psd.

[0012] Optionally, the setting parameters include at least one of the roasting degree of the coffee, the grinding level of the coffee, the type of coffee beans and the type of coffee brewing.

[0013] Optionally, determining the current extraction pressure Psa of the coffee machine comprises:

[0014] Psa=(1-x)·f·Psb Formula (1)

[0015] Wherein, x is the water permeability coefficient of the compressed coffee powder, and f is the water permeability correlation coefficient of the brewer of the coffee machine.

[0016] Optionally, the adjusting the brewing water pressure Psb and / or the pressing force F on the coffee powder comprises:

[0017] The target brewing water pressure Psbt is determined by the following formula (2);

[0018]

[0019] The working parameters of the water pump of the coffee machine are adjusted so that Psb=Psbt.

[0020] Optionally, when the working parameter of the water pump reaches the maximum, if Psa is still not equal to Psd, the brewing water pressure at this time is recorded as Psbmax;

[0021] The method of adjusting the brewing water pressure Psb and / or the pressing force F on the coffee powder further comprises:

[0022] The target pressing force Ft is determined by the following formula (3):

[0023]

[0024] Adjusting the compression device of the coffee machine for compressing the coffee powder so that the compression force of the compression device on the coffee powder is F=Ft;

[0025] Wherein, W is the setting parameter or is determined according to the setting parameter, and Fmax is the maximum compression force that the compression pack can provide to the coffee powder.

[0026] In a second aspect, the present invention provides a coffee machine, comprising:

[0027] A brewing device for containing coffee powder;

[0028] A compression device, used for compressing the coffee powder;

[0029] A water pump, used for supplying water to the brewer;

[0030] A pressure sensor, used to detect the brewing water pressure Psb of the water provided by the water pump;

[0031] The controller is configured to control the coffee machine to execute the control method described in any one of the first aspects.

[0032] Optionally, the coffee machine further comprises a boiler and a temperature sensor, wherein the boiler is connected in series downstream of the water pump and is used to heat the water therein; and the temperature sensor is used to detect the temperature of the water flowing out of the boiler.

[0033] Optionally, the coffee machine further comprises a waste water container and a reversing valve, wherein the waste water container is used to receive cold water; and the reversing valve is used to control the water flowing out of the boiler to flow to the waste water container or to the brewer.

[0034] Optionally, the coffee machine further comprises a water tank, and the water tank is connected in series upstream of the water pump.

[0035] Optionally, the coffee machine further comprises a flow sensor, and the flow sensor is used to detect the flow rate of water flowing from the water tank to the water pump.

[0036] Based on the foregoing description, those skilled in the art can understand that, in the aforementioned technical solution of the present invention, the target extraction pressure Psd of the coffee machine is determined according to the set parameters, so that the brewing water pressure of the coffee machine of the present invention is adjustable. By judging whether the current extraction pressure Psa is equal to the target extraction pressure Psd; and when they are not equal, by adjusting the brewing water pressure Psb and / or the pressing force F on the coffee powder to make the current extraction pressure Psa equal to the target extraction pressure Psd, the coffee machine of the present invention can make the current extraction pressure Psa consistent with the target extraction pressure Psd, thereby ensuring the taste of the final coffee solution.

[0037] Furthermore, the present invention determines the current extraction pressure Psa by Psa=(1-x)·f·Psb, so that the determination of the current extraction pressure Psa takes into account the brewing water pressure Psb, the characteristics of the compressed coffee powder, and the characteristics of the brewer. The value is more accurate and the coffee extraction effect is better. However, those skilled in the art usually only consider the brewing water pressure Psb, and make the brewing water pressure Psb and the target extraction pressure Psd tend to be consistent to extract coffee; they do not consider the characteristics of the compressed coffee powder and the characteristics of the brewer, so the present invention also overcomes this technical bias of those skilled in the art. Moreover, it is precisely because the present invention overcomes this technical bias that the brewing water pressure of the present invention can be adapted to the degree of compression of the coffee powder (water permeability coefficient x) and the water permeability correlation coefficient f of the brewer, so that the coffee powder can be extracted moderately, and the taste is neither too bitter nor too light.

[0038] Other beneficial effects of the present invention will be described in detail below in conjunction with the accompanying drawings so that those skilled in the art can more clearly understand the improved purposes, features and advantages of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solution of the present invention, some embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that the same reference numerals indicate the same or similar components or parts in different drawings; the drawings of the present invention are not necessarily drawn to scale.

[0040] In the attached figure:

[0041] Figure 1 It is a schematic diagram of the principle of the coffee machine provided by the present invention;

[0042] Figure 2 is a flow chart of the steps of a method for controlling the extraction pressure of a coffee machine in some embodiments of the present invention.

[0043] Description of reference numerals:

[0044] 100, coffee machine; 200, coffee powder;

[0045] 101. Brewing device; 102. Compression device; 103. Water pump; 104. Pressure sensor; 105. Controller; 106. Boiler; 107. Temperature sensor; 108. Waste water container; 109. Reversing valve; 110. Water tank; 111. Flow sensor; 112. Coffee nozzle. DETAILED DESCRIPTION

[0046] It should be understood by those skilled in the art that the embodiments described below are only some embodiments of the present invention, rather than all embodiments of the present invention, and these embodiments are intended to explain the technical principles of the present invention, rather than to limit the protection scope of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should still fall within the protection scope of the present invention.

[0047] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "top", "bottom", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the corresponding devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0048] Furthermore, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. For example, the terms "install", "connect", "connect" and "fix", unless otherwise specifically described, can specifically be any feasible connection form such as bolt connection, screw connection, welding, plug-in, riveting, melting, and clamping.

[0049] like Figure 1 As shown, in an example provided by the present invention, the coffee machine 100 includes a brewer 101, a compression device 102, a water pump 103, a pressure sensor 104 and a controller 105.

[0050] The brewer 101 is used to contain coffee powder 200. The brewer 101 can be a container as a whole, such as a cup with an open top. A plurality of filter holes (not shown in the figure) are arranged on the bottom wall of the brewer 101, so that water for brewing coffee powder 200 flows out from the filter holes.

[0051] The compression device 102 is used to compress the coffee powder 200 .

[0052] The water pump 103 is used to supply water to the brewer 101 .

[0053] The pressure sensor 104 is used to detect the brewing water pressure Psb of the water provided by the water pump 103. The pressure sensor 104 can be any feasible sensor such as a piezoresistive sensor, a ceramic sensor, a piezoelectric sensor, etc.

[0054] The controller 105 is configured to control the coffee machine 100 in any of the following embodiments.

[0055] In the present invention, the compression device 102 may be any feasible compression device 102, for example, including an electric push rod and a push plate driven by the electric push rod, so that the coffee powder 200 is squeezed by the push plate when the electric push rod is extended or retracted.

[0056] In the present invention, the controller 105 is an integrated circuit chip having the ability to process signals. The controller 105 may be a general-purpose processor, such as a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, microprocessors, and any other conventional processors. Furthermore, the controller 105 may also have a storage function to store computer programs and data that it can execute.

[0057] Furthermore, in the present invention, the controller 105 may be an integrated functional module or a split functional module. When the controller 105 is a split functional module, it may include a functional module with information processing capability and a functional module with storage capability.

[0058] exist Figure 1 In the example shown, the coffee machine 100 may also include a boiler 106 and a temperature sensor 107 .

[0059] The boiler 106 is connected in series downstream of the water pump 103 and is used to heat the water therein. The boiler 106 may specifically include a container and an electric heating wire arranged inside and / or outside the container to heat the water in the container through the electric heating.

[0060] The temperature sensor 107 is used to detect the temperature of water flowing out of the boiler 106. The temperature sensor 107 can be a resistance sensor or a thermocouple sensor.

[0061] exist Figure 1 In the example shown, the coffee machine 100 may further include a waste water container 108 for receiving cold water and a reversing valve 109 for controlling water flowing out of the boiler 106 to flow to the waste water container 108 or to the brewer 101 .

[0062] exist Figure 1 In the example shown, when the temperature sensor 107 detects that the water temperature has not reached a preset temperature (e.g., 50°C, 75°C, 80°C, 85°C, 95°C, 98°C, etc.), the reversing valve 109 controls the water flowing out of the boiler 106 to flow to the waste water container 108; when the temperature sensor 107 detects that the water temperature has reached a preset temperature, the reversing valve 109 controls the water flowing out of the boiler 106 to flow to the brewer 101, so as to brew the coffee in the brewer 101 at a constant temperature to ensure the taste of the coffee.

[0063] Furthermore, in the water flow path, the reversing valve 109 can be placed as close to the brewer 101 as possible to shorten the path of the hot water from the reversing valve 109 to the brewer 101, thereby preventing the hot water from being cooled due to the long path and affecting the brewing taste of the coffee.

[0064] Accordingly, the temperature sensor 107 is disposed between the reversing valve 109 and the boiler 106 and as close to the reversing valve 109 as possible to shorten the path of hot water from the temperature sensor 107 to the brewer 101 and prevent waste of hot water.

[0065] exist Figure 1 In the example shown, the coffee machine 100 may further include a water tank 110, which is connected in series upstream of the water pump 103. The water tank 110 is used to store and provide water for brewing the coffee powder 200.

[0066] exist Figure 1 In the example shown, the coffee machine 100 further includes a flow sensor 111 for detecting the flow rate of water flowing from the water tank 110 to the water pump 103 .

[0067] Those skilled in the art will appreciate that when the water flow rate detected by the flow sensor 111 suddenly decreases during the operation of the water pump 103, it indicates that the water in the water tank 110 is lacking or has been used up. At this time, the coffee machine 100 allows the user to add water to the water tank 110.

[0068] In the present invention, the flow sensor 111 may be a sensor of any form, such as a vane type, a vortex type, or a Karman vortex type.

[0069] exist Figure 1In the example shown, the coffee machine 100 may further include a coffee nozzle 112 disposed at the bottom side of the brewer 101, for receiving and discharging the coffee solution flowing out of the brewer 101. The coffee nozzle 112 can facilitate the user to receive the coffee solution and prevent the coffee solution from spilling.

[0070] exist Figure 1 In the example shown, the compression device 102, the water pump 103, the temperature sensor 107, the pressure sensor 104, the flow sensor 111, and the reversing valve 109 are electrically connected to the controller 105 respectively, so that the controller 105 obtains the signals of the temperature sensor 107, the pressure sensor 104 and the flow sensor 111, and controls the action or operation of the compression device 102, the water pump 103 and the reversing valve 109.

[0071] The following will refer to Figure 1 The coffee machine 100 shown in the figure is used to describe in detail the method for controlling the extraction pressure of the coffee machine 100 of the present invention.

[0072] It should be noted that Figure 1 This is only an example of the coffee machine 100 to be protected by the present invention. Based on the context of the present invention, those skilled in the art may also modify the coffee machine 100 as needed. Figure 1 Some components of the coffee machine 100 shown in the figure are reduced, replaced, or some components are added, such as adding a liquid level meter for measuring the water level of the water tank 110.

[0073] like Figure 2 As shown, in some embodiments of the present invention, the method for controlling the extraction pressure of the coffee machine 100 includes:

[0074] Step S100, determining the target extraction pressure Psd of the coffee machine 100 according to the set parameters.

[0075] Step S200, determining the current extraction pressure Psa of the coffee machine 100.

[0076] Step S300, determining whether the current extraction pressure Psa is equal to the target extraction pressure Psd.

[0077] Step S400, if they are not equal, adjust the brewing water pressure Psb and / or the pressing force F on the coffee powder 200 so that the current extraction pressure Psa is equal to the target extraction pressure Psd.

[0078] Those skilled in the art can understand that the target extraction pressure Psd of the coffee machine 100 is determined according to the set parameters, so that the brewing water pressure of the coffee machine 100 of the present invention is adjustable. By judging whether the current extraction pressure Psa is equal to the target extraction pressure Psd; and when they are not equal, by adjusting the brewing water pressure Psb and / or the pressing force F on the coffee powder 200, so that the current extraction pressure Psa is equal to the target extraction pressure Psd, the coffee machine 100 of the present invention can make the current extraction pressure Psa of the coffee machine 100 consistent with the target extraction pressure Psd, thereby ensuring the taste of the final coffee solution.

[0079] In step S100 of the present invention, the setting parameters include at least one of the roasting degree of coffee, the grinding gear of coffee, the type of coffee beans and the type of coffee brewing. The setting parameters can be set by the user, and can be determined by the user by operating the control panel or function keys of the coffee machine 100.

[0080] Furthermore, the set parameters correspond to the target extraction pressure Psd and are stored in a database, which may be stored in the controller 105, a memory connected to the controller 105, or a cloud server connected to the coffee machine 100. The database containing the correspondence may be established based on a large amount of experimental data and the experience of professional baristas, or may be determined by the formula (1) described below after setting the water permeability coefficient x of the coffee powder 200, the water permeability correlation coefficient f of the brewer 101 of the coffee machine 100, and the brewing water pressure Psb.

[0081] As an example 1, set the deep roast, the grinding level to medium, the coffee bean type to Arabica, and the brewing shape to espresso. The target extraction pressure Psd corresponding to these setting parameters is determined from the database to be 9 bar.

[0082] According to the common knowledge in the field of coffee extraction, those skilled in the art should know that the darker the roasting degree, the lower the extraction pressure required. The finer the grinding gear, the lower the extraction pressure can be to a certain extent. Different types of coffee beans have different optimal extraction pressures due to their internal structures and ingredients. Different brewing types, such as espresso, require higher pressure to quickly extract a rich coffee liquid, while American coffee requires relatively lower pressure.

[0083] As a second example, medium roasting, coarse grinding, Robusta coffee beans, and American coffee are set. The target extraction pressure Psd corresponding to these setting parameters is determined to be 6 bar from the above database.

[0084] According to common knowledge in the field of coffee extraction, those skilled in the art should know that medium roasted coffee beans require slightly higher pressure than deep roasted coffee beans, the coarse grinding position allows the coffee powder 200 to have a larger contact area with water, and extraction is relatively easy, the characteristics of Robusta coffee beans are different from those of Arabica, and American coffee does not require as high a pressure as espresso.

[0085] As example 3, light roasting, fine grinding, mixed coffee beans (including Arabica and Robusta), and brewing into latte coffee are set. The target extraction pressure Psd corresponding to these setting parameters is determined to be 8 bar from the above database.

[0086] According to common knowledge in the field of coffee extraction, those skilled in the art should know that light roasting requires higher pressure to fully extract the coffee flavor, fine grinding increases the difficulty of extraction but can improve the fineness of the coffee, the characteristics of mixed coffee beans are between the two, and latte requires higher pressure than American coffee to extract a sufficiently rich coffee liquid to mix with milk.

[0087] Those skilled in the art will appreciate that, since there is a certain distance between the detection position of the pressure sensor 104 and the coffee powder 200 in the brewer 101 and the pressure environment is different, the pressure generated when the coffee powder 200 in the brewer 101 is extracted by the water flow is different from the pressure detected by the pressure sensor 104. Therefore, in step S200 of the present invention, the current extraction pressure Psa can be determined by the following formula (1):

[0088] Psa=(1-x)·f·Psb Formula (1)

[0089] In formula (1), x is the water permeability coefficient of the compressed coffee powder 200, and its value range is (0,1). When x=0, it means that the compressed coffee powder 200 is completely impermeable to water; when x=1, it means that the compressed coffee powder 200 is completely permeable to water (equivalent to the fact that the coffee powder 200 does not exist). Therefore, x can be any feasible value such as 0.2, 0.4, 0.5, 0.7, 0.85, etc.

[0090] In the present invention, x can be determined by detecting the magnitude of the water flow before and after the coffee powder 200, or by the following formula:

[0091] x=K·M·N·Fmax÷F.

[0092] Among them, K is the grinding gear of the coffee beans. The finer the coffee beans are ground, the smaller the value of K is, and vice versa. For example, when the grinding gear is fine grinding, K is 0.5; when the grinding gear is medium grinding, K is 1; when the grinding gear is coarse grinding, K is 1.5.

[0093] Wherein, M is the coffee bean type correlation parameter. For example, when the coffee bean type is Robusta, M is 1; when the coffee bean type is Arabica, M is 0.9.

[0094] Where N is a parameter related to the roasting degree of coffee beans. For example, when roasted lightly, N is 0.7; when roasted medium, N is 0.8; and when roasted deeply, N is 0.9.

[0095] Among them, Fmax is the maximum compression force that the compression device 102 can provide to the coffee powder 200, which can be determined by arranging a pressure sensor in the brewer 101 and making the compression device 102 compress the coffee powder 200 at the maximum output power. Alternatively, the corresponding relationship between the input current, voltage and other parameters of the compression device 102 and the compression force F on the coffee powder 200 is determined through experiments, and then the input current, voltage and other parameters of the compression device 102 are obtained to determine the compression force F of the compression device 102 on the coffee powder 200.

[0096] Among them, F is the current compression force provided by the compression device 102 to the coffee powder 200, which can be specifically determined by the pressure sensor 104 provided in the brewer 101.

[0097] Furthermore, the specific values ​​of K, M, and N mentioned above can also be determined by those skilled in the art through multiple experiments.

[0098] In formula (1), f is the water permeability correlation coefficient of the brewer 101 of the coffee machine 100, and its value range is (0,1). When f=0, it means that the brewer 101 is completely impermeable to water; when f=1, it means that the brewer 101 is completely permeable to water (equivalent to the absence of coffee powder 200). Therefore, f can be any feasible value such as 0.2, 0.25, 0.3, 0.5, etc.

[0099] Furthermore, the specific value of f can be determined by calculating the ratio of the total area of ​​the filter holes on the bottom wall of the brewer 101 to the total area of ​​the bottom wall of the brewer.

[0100] For example, if x is 0.5, f is 0.8, and Psb is 6 bar, the current extraction pressure Psa is calculated to be 2.4 bar according to formula (1).

[0101] In step S400 of the present invention, the target brewing water pressure Psbt is first determined by the following formula (2):

[0102]

[0103] Then, the operating parameters of the water pump 103 of the coffee machine 100 are adjusted so that Psb=Psbt.

[0104] The working parameters of the water pump 103 are mainly the rotation speed or duty cycle of the water pump 103 .

[0105] For example, assuming that the current brewing water pressure Psb is 3 bar, the target brewing water pressure Psbt is calculated to be 8 bar according to formula (2). Then, the working parameters of the water pump 103 of the coffee machine 100 are adjusted, and during the adjustment process, the water pressure change is monitored in real time through the pressure sensor 104. When the water pressure reaches 8 bar, the adjustment of the working parameters of the water pump 103 is stopped.

[0106] When the working parameters of the water pump 103 reach the maximum and the water pump 103 operates at the maximum load, if Psa is still not equal to Psd, the brewing water pressure at this time is recorded as Psbmax. Then, the target pressing force Ft is determined by the following formula (3):

[0107]

[0108] Subsequently, the compression device 102 of the coffee machine 100 for compressing the coffee powder 200 is adjusted so that the compression force F of the compression device 102 on the coffee powder 200 is Ft.

[0109] Wherein, W is a setting parameter or is determined according to the setting parameter, for example, W=K·M·N. K, M, and N refer to the above description.

[0110] It should be noted that, in some embodiments of the present invention, steps S100 to S400 may be performed when the reversing valve 109 allows water to flow to the brewer 101, so as to ensure the extraction pressure of the coffee machine 100 on the coffee powder 200. Furthermore, the steps may be performed when the reversing valve 109 allows water to flow to the waste water container 108, so as to ensure the accuracy of the measured brewing water pressure Psb.

[0111] Furthermore, steps S100 to S400 are performed before or during the compression device 102 compresses the coffee powder 200, so as to avoid secondary compression of the coffee powder 200. In this way, the compression force F of the compression device 102 on the coffee powder 200 can be a value measured when the coffee machine 100 last extracted coffee, or a value set and pre-stored in the coffee machine 100 when the coffee machine 100 leaves the factory. The maximum compression force Fmax of the compression device 102 on the coffee powder 200 can be a value pre-stored in the coffee machine 100.

[0112] Alternatively, in some other embodiments of the present invention, steps S100 to S400 may be executed after the user sets parameters for the coffee machine 100, and the Psb, Psbt before adjustment, and the F and Fmax before adjustment are all pre-stored in the coffee machine 100. So that before the coffee machine 100 is operated, the current extraction pressure Psa when the coffee machine 100 is operated according to the four pre-stored parameters can be calculated. When the user sets the parameters, the coffee machine 100 can calculate the target extraction pressure Psd accordingly. Then, the coffee machine 100 compares Psa with Psd, and when Psa≠Psd, the working parameters of the water pump 103 and the compression device 102 are calculated in the manner described above, and then the water pump 103 and the compression device 102 are controlled to operate according to the calculated working parameters. That is, steps S100 to S400 may be executed before the coffee machine 100 is started, specifically, before the coffee machine 100 starts the compression device 102 and the water pump 103.

[0113] That is, in other embodiments of the present invention, the method for controlling the extraction pressure of the coffee machine 100 may further include a step after step S400: controlling the operation of the coffee machine 100 to compress and brew the coffee powder 200 .

[0114] In summary, the present invention can determine the target extraction pressure according to different set parameters, and by adjusting the brewing water pressure and / or the pressing force on the coffee powder 200, effectively make the current extraction pressure equal to the target extraction pressure, thereby achieving precise extraction of different types of coffee and improving the taste of coffee.

[0115] So far, the technical solution of the present invention has been described in combination with the above multiple embodiments, but it is easy for those skilled in the art to understand that the protection scope of the present invention is not limited to these specific embodiments. Without departing from the technical principles of the present invention, those skilled in the art can split and combine the technical solutions in the above embodiments, and can also make equivalent changes or replacements to the relevant technical features. Any changes, equivalent replacements, improvements, etc. made within the technical concept and / or technical principles of the present invention will fall within the protection scope of the present invention.

[0116] In the present invention, the term "communication" means fluid communication, so as to allow fluid (such as air, liquid) to flow between two connected objects. And the "communication" can be to allow the fluid to flow between the two connected objects without leakage, or to allow the fluid to flow between the two connected objects with a little leakage.

Claims

1. A method for controlling extraction pressure of a coffee machine, wherein the coffee machine is configured to compress coffee powder and brew the compressed coffee powder; the control method comprising: Determining a target extraction pressure Psd of the coffee machine according to set parameters; Determining a current extraction pressure Psa of the coffee machine; Determining whether the current extraction pressure Psa is equal to the target extraction pressure Psd; If they are not equal, adjust the brewing water pressure Psb and / or the pressing force F on the coffee powder to make the current extraction pressure Psa equal to the target extraction pressure Psd.

2. The control method according to claim 1, wherein: The setting parameters include at least one of the roasting degree of coffee, the grinding level of coffee, the type of coffee beans and the type of coffee brewing.

3. The control method according to claim 1, wherein: Determining the current extraction pressure Psa of the coffee machine comprises: Psa=(1-x)·f·Psb Formula (1) Wherein, x is the water permeability coefficient of the compressed coffee powder, and f is the water permeability correlation coefficient of the brewer of the coffee machine.

4. The control method according to claim 3, wherein: The adjusting of the brewing water pressure Psb and / or the pressing force F on the coffee powder comprises: The target brewing water pressure Psbt is determined by the following formula (2); The working parameters of the water pump of the coffee machine are adjusted so that Psb=Psbt.

5. The control method according to claim 4, wherein: When the working parameter of the water pump reaches the maximum, if Psa is still not equal to Psd, the brewing water pressure at this time is recorded as Psbmax; The method of adjusting the brewing water pressure Psb and / or the pressing force F on the coffee powder further comprises: The target pressing force Ft is determined by the following formula (3): Adjusting the compression device of the coffee machine for compressing the coffee powder so that the compression force of the compression device on the coffee powder is F=Ft; Wherein, W is the setting parameter or is determined according to the setting parameter, and Fmax is the maximum compression force that the compression pack can provide to the coffee powder.

6. A coffee machine, comprising: A brewing device for containing coffee powder; A compression device, used for compressing the coffee powder; A water pump, used for supplying water to the brewer; A pressure sensor, used to detect the brewing water pressure Psb of the water provided by the water pump; A controller configured to control the coffee machine to execute the control method according to any one of claims 1 to 5.

7. The coffee machine according to claim 6, further comprising a boiler and a temperature sensor, The boiler is connected in series downstream of the water pump and is used to heat the water therein; The temperature sensor is used to detect the temperature of water flowing out of the boiler.

8. The coffee machine according to claim 7, further comprising a waste water container and a reversing valve. The waste water container is used to receive cold water; The reversing valve is used to control the water flowing out of the boiler to flow to the waste water container or to the brewer.

9. The coffee machine according to claim 6, further comprising a water tank, wherein the water tank is connected in series upstream of the water pump.

10. The coffee machine according to claim 9, further comprising a flow sensor for detecting a flow rate of water flowing from the water tank to the water pump.

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