RU2780788C1 - Coffee grinding machine configured to provide different particle size profiles and a corresponding method - Google Patents

Abstract

FIELD: preparation of coffee.

SUBSTANCE: proposed are a coffee grinding machine and an espresso-making machine. System of a coffee grinding machine and an espresso-making machine, wherein the coffee grinding machine comprises a first grinder and a second grinder; wherein at least one from the first and the second grinders is configured to rotate; wherein the grinders interact to grind coffee beans, producing a first dose of ground coffee in the first grinding cycle; wherein the coffee grinding machine comprises an electric engine rotating one of the grinders relative to the other grinder at a speed of rotation; wherein the coffee grinding machine is configured to change the grinding parameter in order to perform the second grinding cycle wherein a second dose of ground coffee is produced; wherein the grinding parameter is changed depending on the quantitative information received from the espresso-making machine and is based on the coffee preparation cycle executed with the first dose of ground coffee; wherein the grinding parameter includes the speed of rotation; wherein the quantitative information contains at least one of the following: the consumption value measured by the flow meter of the espresso-making machine, and the brewing ratio value.

EFFECT: ensured coffee grinding and preparation of espresso.

12 cl, 7 dwg

Description

Prerequisites for the invention

The present invention relates to a machine for grinding coffee beans. The coffee bean grinder may be a stand-alone machine or may be integrated into a coffee-based beverage machine. Such a coffee bean grinder is also known simply as a "coffee grinder", "coffee grinder", or "grinder". The present invention also relates to an espresso coffee machine cooperating with said coffee grinder and to a method for grinding coffee in the form of beans.

State of the art

As you know, to make espresso coffee, a specific amount of ground coffee is used, commonly referred to as a "dose". A dose of ground coffee is loaded into the filter, usually in the form of a cup that is open at the top and has a bottom with micro-perforations. Typically, a dose of coffee is pressed into the interior of the filter to form a puck of coffee powder. The filter, in turn, is supported by a portafilter configured to be removably engaged with the dispensing assembly of the espresso coffee machine. Espresso coffee is made by passing pressurized hot water through a washer of coffee powder.

Coffee powder is obtained using a coffee grinder. In a known coffee grinding machine, coffee beans are ground by passing them through grinding elements. Known grinding elements of a flat, conical or cylindrical type. Typically, the grinding elements of a coffee grinding machine include a stationary element and an element rotating relative to the stationary element. For example, in a coffee grinder with conical grinders, one grinder is fixed and stationary while the other grinder is rotated by an electric motor. Some coffee grinders are capable of varying the distance between the grinders to change the particle size of the coffee powder.

WO 2013/112732 A1 describes an automatic coffee grinder adjustment system.

WO 2009/010190 A1 describes a method for controlling a coffee grinder.

WO 2013/121438 A1 describes a method and a machine for making coffee.

EP 3 042 591 A1 describes a method for adjusting the grinding degree of a coffee grinder.

WO 2014/207281 A1 describes a coffee grinder control device.

Disclosure of invention

The Applicant has experimented with ground coffee powder. For the purposes of the present invention, it is considered that the ground coffee powder is formed essentially by particles or granules that have a theoretical characteristic size. This theoretical characteristic dimension will also be referred to hereinafter as "equivalent diameter". In addition, the expression "ground coffee" can be used as an alternative to the more complete expression "ground coffee powder" or "coffee powder".

The Applicant has found that all known coffee grinding machines, regardless of the manufacturer or type of grinding elements or the particular mechanism used, produce ground coffee containing granules that vary widely in size. The range of equivalent diameters includes three orders of magnitude, from a few microns to more than one millimeter.

The relative abundance of granules can be expressed as a particular profile, called "particle size profile", which has a progression (regardless of the coffee grinder used) similar to the progression shown in FIG.

The curve that shows the particle size profile is called the bimodal profile. The large peak (on the right) is called the "first form", while the small peak (on the left) is called the "second form".

As briefly mentioned above, the purpose of ground coffee is to be used in an espresso machine to dispense coffee drinks.

As is apparent, particle sizes when there are a large number of fine particles result in less water flow and therefore coffee that is "stronger" for the same dosing time compared to particle sizes when there are more large particles.

As a general rule, each barista adjusts their coffee grinder accordingly to obtain the particle size they feel provides the optimum beverage.

Whether the machine has flat grinders, conical grinders or cylindrical grinders, the smaller the distance between the grinding elements, the larger the amount of fine particles and the smaller the amount of coarse particles. By increasing the distance between the grinding elements, the opposite result is obtained.

As a rule, many manufacturers of known coffee grinding machines have used the same system for changing the particle size, ie changing the distance between the grinding elements.

The Applicant has found that changing the distance between the grinding elements not only changes the relative amount of larger and smaller parts of ground coffee, but also shifts the peak of the first form horizontally, when the distance between the grinders is increased, the peak moves to the right (toward larger particle sizes), whereas as the distance between the grinders decreases, the peak moves to the left (toward fine particle sizes).

In commercially available systems, changing the spacing between shredders can be done manually or electrically using an electric drive (usually an electric motor).

Applicant has identified the goal of providing a coffee grinder capable of providing a dose of ground coffee having a predetermined particle size profile to obtain a predetermined flow rate (in terms of volume flow or mass flow) when the dose is used to make espresso coffee in an espresso machine. In turn, the ratio between consumption and dose affects the ratio during cooking.

For the purposes of the present specification and claims, the expression "brewing ratio" (concentration or concentration ratio of the beverage) or "brewing ratio" is understood to mean the ratio between the mass of ground coffee used and the mass of the final beverage dispensed.

The Applicant has found that different grinder rotation speeds create different particle size profiles. In particular

as the speed decreases, finer powders are obtained on average, and

as the speed increases, coarser powders are obtained on average.

In accordance with the present invention, a coffee grinding machine is described in which different particle size profiles are obtained by appropriately varying the rotational speed of the grinders depending on external information, such as information relating to flow (volume flow or mass flow).

According to the first aspect, a coffee grinder and an espresso machine are described,

wherein the coffee grinder comprises a first grinder and a second grinder, wherein at least one of the first and second grinders is rotatable, said grinders cooperating with each other to grind coffee beans, producing a first dose of ground coffee during the first grinding cycle, wherein said coffee grinding machine comprises an electric motor that rotates one of the grinders relative to the other grinder at a rotational speed, wherein the coffee grinding machine is configured to change the grinding parameter to carry out a second grinding cycle in which a second dose of ground coffee is obtained,

wherein said grinding parameter varies depending on quantitative information received from said espresso coffee machine and is based on a coffee brewing cycle carried out with said first dose of ground coffee,

wherein said grinding parameter contains the rotation speed,

wherein said quantitative information comprises at least one of the following: a flow value measured by a flow meter of said espresso coffee machine and a brewing ratio value.

The espresso coffee machine is connected or connected to the coffee grinder and forms a unit or complex.

For the purposes of the present specification and the appended claims, the expression "brewing ratio" (concentration or strength of beverage) or "brewing ratio" is understood to mean the ratio between the mass of ground coffee used and the mass of the final beverage dispensed.

For the purposes of the present description and the appended claims, two beverages have the same brewing ratio when the above ratio is identical or differs by a certain percentage (in absolute terms) of less than 10%, preferably less than 5%, and even more preferably less than 2-3%.

According to embodiments, the first dose is milled during the milling cycle just before the second dose is milled.

According to embodiments, a connection module for co-connecting an espresso coffee machine and a coffee grinder is also described.

The connection module may be configured to wirelessly connect the coffee grinder to the espresso coffee machine.

Preferably, a comparator may be installed to compare the flow rate to the flow reference, and a speed variator may be installed to (i) decrease the motor speed if the flow is greater than the reference flow, (ii) increase the motor speed if the flow is less than the reference flow rate, and (iii) maintaining the motor speed if the flow rate value is substantially the same as the flow reference value.

According to embodiments, a first device for measuring the mass of said first dose of ground coffee, a second device for measuring the mass of brewed espresso coffee, and a processor for calculating a brewing ratio corresponding to the ratio between said mass of the first dose and said mass of espresso coffee prepared with said first dose.

In accordance with embodiments, a comparator for comparing a brew ratio value with a reference brew ratio value and a speed variator are also described, wherein said speed variator is configured to (i) reduce the motor speed if the brew ratio value is greater than the reference brew ratio value. , (ii) increasing the motor speed if the brew ratio is less than the flow rate reference, and (iii) maintaining the motor speed if the brew ratio is substantially the same as the reference brew ratio.

According to another aspect, a method for grinding coffee beans is described, comprising:

providing first and second grinders cooperating with each other, wherein at least one of the first and second grinders is rotatable, said grinders cooperating with each other to grind coffee beans, obtaining a first dose of ground coffee during the first grinding cycle,

providing an electric motor for rotating one of the shredders relative to the other at a rotation speed,

changing the grinding parameter for performing a second grinding cycle in which a second dose of ground coffee is obtained, wherein said grinding parameter changes depending on the quantitative information received from the coffee machine and based on the coffee preparation cycle with said first dose of ground coffee,

wherein said grinding parameter contains the rotation speed,

wherein said quantitative information comprises at least one of the following: a flow rate value and a cooking ratio value.

The first dose is preferably crushed during the grinding cycle immediately prior to grinding the second dose.

The method may also include the step of comparing the flow rate value with a reference flow rate value and

(i) decreasing the motor speed if the flow rate is greater than the reference flow rate,

(ii) increasing the motor speed if the flow rate is less than the reference flow rate, and

(iii) maintaining the rotational speed of the motor if the flow rate is substantially the same as the reference flow rate.

The method may also include the step of measuring the mass of said first dose of ground coffee, measuring the mass of brewed espresso coffee and calculating the brewing ratio corresponding to the ratio between said mass of the first dose and said mass of espresso coffee prepared with said first dose.

A step may also be provided for comparing the cooking ratio value with a reference cooking ratio value, and

(i) decreasing the motor speed if the brew ratio value is greater than the reference brew ratio value,

(ii) increasing the motor speed if the brew ratio value is less than the reference brew ratio value, and

(iii) maintaining the rotation speed of the motor if the cooking ratio value is substantially the same as the cooking ratio reference value.

Brief description of the drawings

Now follows a detailed description of the invention, presented as a non-limiting example, which should be read with reference to the accompanying drawings, in which

- Fig. 1 is a graph showing an example of a particle size profile plotted on a logarithmic scale;

- Fig. 2 is a graph showing particle size profiles plotted on a logarithmic scale;

- Fig. 3 is a graph showing three particle size profiles plotted on a linear scale;

- Fig. 4 is a schematic view of a coffee grinder according to an embodiment of the present invention;

- Fig. 5 is another schematic view of a coffee grinder according to the present invention in association with an espresso coffee machine;

- Fig.6 is a diagram of the sequence of operations of the operating mode; and

- Fig. 7 is an exemplary view of an espresso coffee machine with weighing and processing devices for calculating the brewing ratio value.

Detailed description of the invention

Figure 1, which has already been briefly referred to above, is a graph showing an example of a granulometric dose profile of coffee powder. The curve that shows the particle size profile is called the bimodal profile. The high peak (on the right, referring to larger particles) is called the "first form", while the low peak (on the left, referring to smaller particles) is called the "second form".

Figures 2 and 3 show the influence of the speed of rotation of the grinders relative to the size of the particles. In particular, figures 2 and 3 show three particle size curves obtained by maintaining a constant distance between the grinders and by changing the rotation speed. The two drawings show the same profiles plotted on a logarithmic scale to highlight differences in the second shape and on a linear scale to highlight differences in the first shape.

As can be seen, at a lower speed (150 rpm) the first shape shifts to the left and its relative magnitude decreases in favor of the second shape.

At a higher speed (300 rpm), the first shape moves to the right and increases its relative value.

In the case of FIG. 2 (which shows only an example), the first waveform at 150 rpm is located at about 425 µm, while the first waveform at 300 rpm is located at about 475 µm.

Speed change is achieved with a suitable electronic speed controller for electric motors. Many devices of this type, which differ depending on the type of motor used, are commercially available. According to an embodiment of the present invention, the coffee grinder comprises a three-phase asynchronous electric motor and, for speed control, an inverter or any known frequency variator.

Figure 4 schematically shows the main elements of the machine 10 for grinding coffee in accordance with embodiments of the present invention.

The machine 10 includes a grinding chamber 12 with a top inlet for coffee to be ground, a first grinder 14A and a second grinder 14B cooperating with the first grinder 14A, and an outfeed conveyor 16 which receives ground coffee from grinders 14A and 14B and moves it to collect and use. For example, as shown in FIG. 4, ground coffee may be moved into a filter 21 supported by any known type of portafilter 20.

According to the embodiment of FIG. 4, the first grinder 14A is a fixed grinder, while the second grinder 14B is movable, such as rotating.

The coffee grinder includes a motor 30 for rotating the second grinder 14B at a specific rotation speed. According to embodiments, the motor is a single-phase motor. For example, a motor is a motor containing one of the following types: universal, DC, single-phase or three-phase AC, brushless, brushless DC, stepper, or other type of motor.

Preferably, the coffee grinder further comprises a frequency variator 40 for adjusting the rotation speed. For example, this frequency variator contains an inverter. This frequency variator 40 provides a change in the grinding speed to ensure a constant grinding at the first speed or at the second speed.

According to embodiments, the coffee grinder further comprises an angle position sensor, such as a rotation angle sensor 50, coupled to the motor to accurately measure the rotational speed of the motor 30.

In accordance with embodiments, the rate change may be performed by the barista through a suitable interface 70 (FIG. 5). The interface 70 may, for example, comprise a button (or a plurality of buttons) for selecting a set rotation speed, a rotary knob for selecting (continuous or intermittent) a plurality of rotation speeds, or a touch screen for selecting from the various options/speeds available. Interface 70 is connected to inverter 40 (directly or through other devices such as processor 60 shown schematically in FIG. 5) to change the frequency of the motor 30 and hence the speed of the latter. Preferably, it may be possible to select the rotation speed from among the rotation speeds offered by the manufacturer or the speed selected by the user. Preferably, a memory can be installed to store rotational speed values.

In accordance with other embodiments, a control unit (processor 60) is installed, configured to set the rotation speed of the electric motor 30 depending on external signals, for example, supplied by the coffee machine 90 connected/associated with the said coffee grinder 10. According to embodiments, the external signals that affect the rotational speed of the motor 30 are not environmental signals (pressure, humidity, or temperature), but are related to the operation of the espresso coffee machine.

The connection between the coffee machine 90 and the coffee grinder 10 may be via a cable (eg, a standard data cable or fiber optic cable) or may be via a wireless connection, such as based on the industry technical standard for wireless personal area networking. For example, the connection may be via the Bluetooth standard or the like. The connection can also be optical and based on a wireless network. FIG. 5 schematically shows a wireless connection between coffee machine 90 and coffee grinder 10 via a communication module (eg, receiver or transceiver).

In accordance with embodiments, the speed of the motor 30 varies depending on information related to the amount of flow measured in the espresso machine 90. The consumption information is preferably consumption information obtained during an espresso coffee brewing cycle using machine 90 using a dose of coffee powder ground during the grinding step prior to performing the grinding process. Preferably, the preceding grinding step is the grinding step immediately preceding the execution of the grinding step. The flow rate can preferably be measured using the flow meter 91 of the espresso machine 90 . The flowmeter 91 may be located in any position in the hydraulic circuit of the machine 90, for example, near the metering unit of the machine 90.

Fig. 6 schematically shows a possible way of carrying out the steps by which the rotation speed of the motor 30 is changed depending on the consumption information received from the respective coffee machine.

After receiving the flow rate information from the espresso machine (step 100), an evaluation is performed to check if the measured flow rate is outside a predetermined tolerance range (step 101), that is, if it is different from the (required) reference value plus or minus the threshold value .

If the measured flow rate relative to the standard dose is within the tolerance range, no change in the motor speed (step 102) is performed, and therefore the dose reduction is performed in the same way as for the reduction of the standard dose, i.e., as a rule, the reduction of the previous doses.

If the measured flow rate relative to the standard dose is greater than the desired value (taking into account also the tolerance range), the rotational speed of the motor is increased (steps 103 and 105).

If the measured flow rate relative to the standard dose is less than the desired value (taking into account also the tolerance range), the rotational speed of the motor is reduced (steps 103 and 104).

In accordance with other embodiments, the speed V of the electric motor 30 varies depending on information related to the brew ratio value measured in the espresso machine 90. The brew ratio information is preferably the brew ratio information obtained during the espresso coffee brewing cycle with the machine 90 using the dose of coffee powder ground during the grinding step prior to performing the grinding process. Preferably, the preceding grinding step is the grinding step immediately preceding the grinding step in progress.

According to embodiments, machine 90 as shown in FIG. 7 includes means for calculating a brewing ratio between the weight (or weight) of the amount of ground coffee used to make espresso coffee and the weight (or weight) of espresso coffee actually brewed. As is known, consumers require espresso coffee in dosages and/or diluted to varying degrees, depending on their particular habits and tastes and/or depending on the usual practice of the place where they are. Thus, the consumer may require strong coffee, regular coffee, less intense coffee, etc. The consumer can also order single, double, triple, etc., espresso coffee.

Said means for calculating the brewing ratio may include a first weighing device 95 for measuring the mass of ground coffee (for example, directly in the filter supported by portafilter 20), a second weighing device 96 for measuring (directly in the cup) the mass of brewed espresso coffee, and a processing device (processor ) configured to at least obtain a ground coffee weight measurement and a brewed espresso coffee weight measurement and obtain said brewing ratio from the two weight measurements. Figure 7 also shows a schematic view of two metering units 99, made with the possibility of engagement with the portafilter 20.

Therefore, the motor speed is selected depending on the quantitative information received from the coffee machine for which the ground coffee is intended. Preferably, the value derived from the dose is used to select what to maintain or change the grinding parameters (eg, grinding speed) of the next dose.

The system can perform the function both in an open loop, i.e., without measuring the actual speed V of rotation of the electric motor, and in a closed loop, i.e., determining the speed of the electric motor using a special device, for example, a speed sensor 50 (rotation angle sensor ).

Preferably, in accordance with the present invention, the problem of determining the balance in particle size in grinding between single coffee and double coffee can be solved. For example, two buttons may be provided, one for single dose grinding and one for double dose grinding. In accordance with the present invention, for single dose grinding, the coffee grinder can be programmed such that a particular speed V1 (to obtain a particular particle size) and a first quantity W1 are associated with a corresponding button. Similarly, in accordance with the present invention, for double dose grinding, the coffee grinder can be programmed such that a particular speed V2 (to obtain a particular particle size) and a second amount W2 are associated with the appropriate button.

Even if there is a need to alternate single coffee at V1 and double coffee at V2, the system will not suffer as a result.

Such flexibility is highly desirable. In fact, currently the particle size chosen by the barista is necessarily a compromise between a single dose and a double dose. With the present invention, this limitation is eliminated.

Claims (27)

1. System from a machine (10) for grinding coffee and an espresso machine, moreover, the machine (10) for grinding coffee contains a first grinder (14A) and a second grinder (14B), while at least one (14B) of the first and second grinders (14A, 14B) is rotatable, and the grinders (14A, 14B) interact with each other to grind coffee beans, obtaining the first dose of ground coffee during the first grinding cycle, and the machine (10) for grinding coffee contains an electric motor (30) that rotates one (14B) of the grinders relative to the other grinder (14A) with a rotation speed, while the machine (10) for grinding coffee is configured to change the grinding parameter to perform a second grinding cycle, in which a second dose of ground coffee is obtained, wherein the grinding parameter varies depending on the quantitative information received from the espresso coffee machine and is based on the coffee brewing cycle performed with the first dose of ground coffee, in this case, the grinding parameter includes the rotation speed, wherein the quantitative information comprises at least one of the flow rate measured by the flow meter of the espresso coffee machine and the brewing ratio value. 2. The system of claim. 1, in which the first dose is crushed during the grinding cycle immediately before grinding the second dose. 3. The system according to claim 1 or 2, further comprising a connection module for connecting together the espresso machine and coffee grinder (10). 4. System according to claim 3, wherein the connection module is configured to wirelessly connect the coffee grinder (10) to the espresso coffee machine. 5. The system according to any one of the preceding claims, comprising a comparator for comparing the flow rate with the reference flow rate and a speed variator (40) configured to (i) reduce the speed of rotation of the motor (30) if the flow rate is greater than the reference flow rate, (ii ) increasing the speed of the motor (30) if the flow rate is less than the reference flow rate, and (iii) maintaining the speed of the motor (30) if the flow rate is substantially the same as the reference flow rate. 6. The system according to any one of the preceding claims, also comprising a first device (95) for measuring the mass of the first dose of ground coffee, a second device (96) for measuring the mass of the prepared espresso coffee, a processor (CPU) for calculating the brewing ratio corresponding to the ratio between the mass the first dose and the mass of espresso coffee prepared with the first dose. 7. The system according to claim 6, comprising a comparator for comparing the cooking ratio value with the cooking ratio reference value and a speed variator configured to (i) reduce the rotation speed of the electric motor (30) if the cooking ratio value is greater than the cooking ratio reference value. cooking, (ii) increasing the rotation speed of the motor (30) if the cooking ratio value is less than the reference flow rate, and (iii) maintaining the rotation speed of the electric motor (30) if the cooking ratio value is substantially the same as the reference ratio when cooking. 8. Method for grinding coffee beans, including: providing first and second grinders (14A, 14B) interacting with each other, wherein at least one (14B) of the first and second grinders (14A, 14B) is rotatable, the grinders interacting with each other to grind coffee beans, receiving the first dose of ground coffee during the first grinding cycle, providing an electric motor (30) for rotating one (14V) of the grinders relative to the other (14A) at a rotation speed, changing the grinding parameter to perform a second grinding cycle in which a second dose of ground coffee is obtained, the grinding parameter changing depending on the quantitative information received from the coffee machine and based on the coffee preparation cycle performed with the first dose of ground coffee, wherein the grinding parameter contains the rotation speed, moreover, the quantitative information contains at least one of the following: the value of the flow rate and the value of the relationship when cooking. 9. The method of claim. 8, wherein the first dose is ground during the grinding cycle immediately prior to grinding the second dose. 10. The method according to claim 8 or 9, further comprising the step of comparing the flow rate with the reference flow rate and (IV) decrease the rotation speed of the motor (30) if the flow rate is greater than the reference flow rate, (V) increasing the speed of the motor (30) if the flow rate is less than the reference flow rate, and (VI) maintaining the rotational speed of the motor (30) if the flow rate is substantially the same as the reference flow rate. 11. The method according to paragraphs. 8, 9 or 10, including the step of measuring the mass of the first dose of ground coffee, the step of measuring the mass of the prepared espresso coffee and calculating the brewing ratio corresponding to the ratio between the mass of the first dose and the mass of the espresso coffee prepared with the first dose. 12. The method of claim 11, further comprising the step of comparing the cooking ratio value with the reference cooking ratio value, and (IV) decreasing the rotation speed of the motor (30) if the brewing ratio value is greater than the brewing ratio reference value, (V) increasing the rotation speed of the motor (30) if the brew ratio value is less than the reference brew ratio value, and (VI) maintaining the rotation speed of the motor (30) if the cooking ratio value is substantially the same as the cooking ratio reference value.

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