Method for operating, in particular for calibrating, a coffee machine

Abstract

The invention relates to a method for operating or calibrating a coffee machine (1) and comprises four measures a) to d). According to a first measure a), the coffee machine (1) is provided. This comprises a storage container (2) for holding water (W), which communicates fluidly with a brewing device (4) via a water channel (3) through which the water (W) flows. Arranged in the water channel (3) are a conveying device (5) for conveying the water (W) from the storage container (2) into the brewing device (4) and a heating device (6) for heating the water (W) conducted through the water channel (3). In a second measure b), water (W) is conveyed from the storage container (2) through the water channel (3) into the brewing device (4) at a predetermined set target conveying capacity (PF-S) of the conveying device (5).The water conducted through the water channel (3) is heated by setting a specific target heating output (PH-S) for heating the water (W) in the heating device (6). According to a third measure c), the time period (T) that has elapsed since the activation of the heating device (6) until a temperature increase (TEMP+) was detected in the pumped water due to its heating by the heating device (6) is determined using a temperature sensor (7a). In a fourth measure d), the time period (T) determined in measure c) is compared with a stored reference time period (T-REF) and an actual pumping output (PF) of the pumping device (5) is determined from this comparison.

Description

The invention relates to a method for operating, in particular for calibrating, a coffee machine, in particular a fully automatic coffee machine, and to a coffee machine or a fully automatic coffee machine which is set up / programmed for carrying out this method. The invention also relates to a computer program product and a data carrier for executing the method.Methods for operating a coffee machine are known, for example, from DE 10 2007 059 769 A1 and DE 10 2011 079 542 B3.Coffee machines in the form of so-called fully automatic coffee machines are equipped with a storage container for storing water, which is connected fluidically via a water channel to a brewing chamber for preparing a coffee hot beverage from coffee beans and the heated water.For transporting the water into the brewing chamber, a conveying device, often in the form of an electric water pump, is typically arranged in the water channel. The quality of the hot coffee beverage prepared in the brewing chamber depends to a considerable extent on the amount of water used in the brewing chamber for preparation. The amount of water conveyed into the brewing chamber is in turn dependent on the conveying capacity of the conveying device arranged in the water channel. Therefore, accurate knowledge of the conveying capacity of the conveying device is important. In particular, it is important to know tolerance-related deviations of individual conveying devices in coffee machines of the same series in order to be able to take these into account when activating the conveying device.It is therefore an object of the present invention to provide an improved method for operating, in particular for calibrating a coffee machine, which takes into account the above-mentioned problem.This object is achieved by the subject matter of the independent claims. Preferred embodiments are the subject of the dependent claims.The basic idea of the invention is accordingly to calibrate the conveying device of each individual manufactured coffee machine individually with respect to its conveying capacity. For this purpose, at a specific set setpoint conveying capacity of the conveying device, a heating device arranged in the water channel is activated. By means of a temperature sensor arranged downstream of the heating device in the water channel, it can be determined which time period has elapsed since the activation of the heating device until the temperature of the water guided through the water channel begins to increase due to the heating that takes place, starting from an initial temperature of the water before the beginning of the heating process. This time duration correlates with the delivery rate of the delivery device: the greater the actual delivery rate, the shorter the time duration that passes until an increase in the water temperature occurs. The lower the conveying capacity of the conveying device, the greater this time duration.By comparing the actually determined time duration with a stored reference time duration, which was determined in a calibrated reference coffee machine, it is possible to determine whether the actual delivery rate of the delivery device of the coffee machine to be calibrated matches the set desired delivery rate-as is the case with the reference coffee machine-or deviates therefrom. In the latter case, the deviation of the actual delivery rate from the set setpoint delivery rate determined with the aid of the method according to the invention can be taken into account during operation of the coffee machine, and thus during the brewing process and during the transport of water into the brewing chamber. By means of the calibration described above, it is thus ensured that in all coffee machines calibrated in this way, the desired amount of water is also actually transported from the storage container into the brewing chamber, so that the initially mentioned quality losses during the preparation of the coffee hot beverage are avoided.The method according to the invention serves for operating or calibrating a coffee machine and comprises four measures a) to d). According to a first measure a), the coffee machine is provided. This comprises a storage container for receiving water, which communicates with a brewing device via a water channel through which the water can flow. Typically, the water received in the storage container has ambient temperature. In the water channel, a conveying device for conveying the water from the storage container into the brewing device and a heating device for heating the water guided through the water channel are arranged.In a second measure b), water is conveyed from the storage container through the water channel into the brewing device under a predetermined set setpoint conveying capacity of the conveying device. In the present case, "delivery rate" can mean an amount of water delivered through the channel cross section at a specific position of the water channel per unit time.The water guided to the brewing device is heated in the water channel by setting a specific desired heating power in the heating device for heating the water. The setpoint heating power can be, for example, an electrical power supplied to the heating device if the heating device is an electrical heating device. According to a third measure c), the time period that has elapsed since the activation of the heating device until a temperature increase starts in the conveyed water due to its heating is determined with the aid of a temperature sensor. In a fourth measure d), the time duration determined in measure c) is compared with a stored reference time duration and an actual conveying capacity of the conveying device is determined from this comparison-this can deviate from the set desired conveying capacity. This results in the calibration of the conveying device of the coffee machine carried out in measures a) to d).In a preferred embodiment of the process according to the invention, the temperature increase ascertained in measure c) can be arbitrarily small compared to the starting temperature. This means that, in order to determine the time period that has elapsed since the start of the heating process, the detected temperature increase is essentially defined by the measurement accuracy of the temperature sensor. As soon as the temperature sensor detects an increase in temperature relative to the initial temperature of the water at the beginning of the heating process, this time is used to determine the time duration that has elapsed from the start of the heating process. The period of time that has elapsed between the starting time and the time of detecting a temperature increase can then be assumed as the period of time.Alternatively, however, it can also be provided that the temperature increase ascertained in measure c) has to have exceeded a predetermined threshold value compared to the starting temperature. As soon as the temperature sensor detects an increase in the temperature of the water by said threshold value relative to the initial temperature of the water at the beginning of the heating process, this time is used to determine the time duration that has elapsed from the start of the heating process. In this alternative variant too, the period of time that has elapsed between the starting time and the time of detecting the temperature increase is assumed as the period of time.According to an advantageous development of the method according to the invention, the actual conveying rate is determined as a function of a difference between the determined time duration and the stored reference time duration. If the determined time duration is thus unambiguously assigned to that coffee machine in which this time duration was determined, the deviation of the actual delivery rate from the predefined setpoint delivery rate can be taken into account individually in this way when controlling the delivery device for each individual coffee machine.For the unique assignment of the time duration determined for a specific coffee machine by means of the method according to the invention to this coffee machine, it is therefore proposed according to a further preferred embodiment to store the time duration determined in measure c) in a storage unit of the coffee machine. It is thus available as a calibration value for setting the delivery rate of the delivery device during operation of the coffee machine.Particularly preferably, as a function of the actual delivery rate calculated in measure d), a volume flow of the water through the water channel can be calculated by means of a stored transfer function. Further operating parameters of the coffee machine can also be included in this transfer function.According to an advantageous development of the method according to the invention, a calibration of the heating device is also carried out taking into account the calibration of the conveying device carried out in measures a) to d). In other words, the calibration of the heating device presupposes a previously performed calibration of the conveying capacity of the conveying device in order to at least counteract an undesired propagation of errors during the calibration of the heating device, caused by an uncalibrated conveying device.Particularly preferably, three measures k 1), k 2) and k 3) can be carried out one after the other in order to calibrate the heating device. According to a first measure k 1), a predetermined setpoint heating power is set in the heating device. According to a second measure k2), the temperatures TEMPor TEMP* of the water W conveyed through the water channel by means of the conveying device are measured both upstream (TEMP*) and downstream (TEMP) of the heating device.In a third measure k3), a difference DIFF between the two temperature values TEMP, TEMP* measured in measure k2) is determined, i.e. DIFF=TEMP-TEMP*. In addition, in measure k3), an actual heating power PH of the heating device is determined by comparing the difference DIFF with a stored reference difference DIFF-R between the two temperature values TEMP, TEMP*. The calibration of the heating device thus takes place in principle in a manner analogous to the previous calibration of the conveying device. The difference DIFF determined can therefore also be stored in the memory unit of the open-loop / closed-loop control device and can thus be taken into account as an individual calibration value in each coffee machine produced when actuating the heating device.Preferably, the execution of measure k3) is started only after the temperature TEMP measured downstream of the heating device has converged to a predetermined limit value TEMP-G. In this way, it is excluded that the calibration or the accuracy of the calibration process can be significantly disturbed by short-term temperature fluctuations in the temperature of the water flowing through the water channel.In another preferred embodiment, before performing measure k1), the water channel is rinsed with water at ambient temperature. In this way, a uniform starting temperature advantageous for the calibration process is set in the water channel including the storage container and thus also in the water located there.The invention further relates to a coffee machine, in particular a fully automatic coffee machine. The coffee machine according to the invention comprises a storage container for receiving water, which communicates fluidically with a brewing device of the coffee machine via a water channel of the coffee machine through which the water can flow. In the water channel, a conveying device of the coffee machine with adjustable (nominal) conveying capacity for conveying the water from the storage container into the brewing device and a heating device of the coffee machine with adjustable (nominal) conveying capacity for heating the water guided through the water channel are arranged. Preferably, the conveying device is arranged upstream of the heating device in the water channel. The delivery device can be a conventional, in particular electrically driven, water pump. Furthermore, the coffee machine according to the invention comprises a control / regulating device for setting a setpoint conveying capacity in the conveying device and for setting a setpoint heating capacity in the heating device. The control / regulation device is thus set up / programmed for controlling both the conveying device and the heating device. According to the invention, the open-loop / closed-loop control device is set up / programmed for carrying out the method according to the invention presented above. The advantages of the method according to the invention explained above are therefore transferred to the coffee machine according to the invention.In a preferred embodiment of the coffee machine according to the invention, it comprises a first temperature sensor for measuring the temperature of the water conducted through the water channel downstream of the heating device and a second temperature sensor for measuring the temperature of the water upstream of the heating device. The two temperature sensors are connected in a data-transmitting manner to the control / regulating device of the coffee machine, so that the latter can process and evaluate sensor data respectively generated by the two temperature sensors relating to the measured temperature TEMPor TEMP*.The invention further relates to a computer program product configured for executing the method, in particular by means of the control / regulation device of the coffee machine.The computer program product contains commands which, when the computer program product is executed by a computer system, cause the computer system and / or by the control / regulation device of the coffee machine to execute the method.Finally, the invention relates to a computer-readable data carrier for carrying out the method.The data carrier comprises instructions which, when executed, cause a computer system and / or the deep learning system to execute the method according to the invention explained above.Further important features and advantages of the invention are evident from the dependent claims, from the drawing and from the associated description of the figures with reference to the drawings.It is understood that the features mentioned above and those still to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.Preferred exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally the same components.They show, in each case schematically: FIG. 1 shows an example in a coffee machine according to the invention in a roughly schematic partial view, FIG. 2 shows a flow chart illustrating the method according to the invention by way of example.FIG. 1 shows a schematic partial illustration of an example of a coffee machine 1 according to the invention for producing a coffee hot beverage, which can be designed as a fully automatic coffee maker for this purpose. The coffee machine 1 comprises a storage container 2 for receiving water W, which communicates fluidically via a water channel 3 of the coffee machine 1 through which the water W can flow with a brewing device 4 which. Arranged in the water channel 3 are a conveying device 5 of the coffee machine 1 with adjustable desired conveying capacity PF-S for conveying the water W from the storage container 2 into the brewing device 4 and a heating device 6 of the coffee machine 1 with adjustable desired heating capacity PH-S for heating the water W guided through the water channel 3. In the example, the conveying device 5 is arranged upstream of the heating device 6 in the water channel 3. The delivery device 5 can be formed by an electrically driven water pump 5 a.The coffee machine 1 further comprises a first temperature sensor 7a for measuring the temperature TEMP of the water conducted through the water channel 3 downstream of the heating device 6 and a second temperature sensor 7b for measuring the temperature TEMP* of the water W upstream of the heating device 6.The coffee machine further comprises a control / regulating device 10 for setting a setpoint conveying capacity in the conveying device 5 and for setting a setpoint heating capacity in the heating device 6. In addition, the control / regulation device 10 is connected to the two temperature sensors 7 a, 7 bin a data-transmitting manner, so that it can process and evaluate sensor data generated by the two temperature sensors 7 a, 7 bin each case relating to the measured temperatures TEMPor TEMP*. The control / regulation device 10 of the coffee machine 1 is also set up / programmed for carrying out the method according to the invention.Further components of the coffee machine 1, such as a grinding mill for grinding coffee beans, are not relevant to the method according to the invention and are therefore not explained in more detail.The method according to the invention is explained below by way of example with reference to the flow chart shown in FIG. 2.The method according to the invention serves for operating or calibrating the coffee machine 1 and comprises four measures a) to d).According to a first measure a), the coffee machine 1 to be calibrated is provided. As already explained with reference to FIG. 1, this therefore comprises a storage container 2 for receiving water W, which communicates with a brewing device 4 via a water channel 3 through which the water W can flow. In the water channel 3 there are arranged a conveying device 5 for conveying the water W from the storage container 2 into the brewing device and a heating device for heating the water guided through the water channel.In a second measure b), water is conveyed from the storage container 2 through the water channel 3 into the brewing device 4 under a predetermined set setpoint conveying rate PF-S of the conveying device 5. In this case, the water W conducted through the water channel 3 is heated starting from an initial temperature TEMP-0, which can be the ambient temperature of the coffee machine 1. For this purpose, a specific setpoint heating power PH-S for heating the water W is set in the heating device 6. According to a third measure c), the time duration T that has elapsed since the activation of the heating device 6 until an increase in temperature TEMP+ that has occurred is determined in the conveyed water W due to the heating by the heating device 6 is determined with the aid of a temperature sensor 7 aarranged downstream of the heating device 6 in the water channel 3. In a fourth measure d), the time duration T determined in the measure is compared with a stored reference time duration T-REF, and an actual conveying capacity PF of the conveying device 5-this can deviate from the set setpoint conveying capacity PF-S-is determined from this comparison.In the example scenario, the temperature increase TEMP+ relative to the initial temperature TEMP-0 of the water W determined in measure c) must have exceeded a predetermined threshold value TEMP-S before heating. Said time duration T is thus the time difference between the time of detecting the temperature increase TEMP+and the time at which the heating process was started.The actual delivery rate PF for the control of the delivery device can thus be determined as a function of a difference ΔT between the determined time duration T and the stored reference time duration T-REF. In addition, the time duration T determined in measure c) can be stored in a memory unit 8 of the coffee machine 1 (cf. FIG. 1 ).On the basis of the calibration of the conveying device 5 carried out in measures a) to d), in a further measure e), a volume flow V of the water W through the water channel 3 can be calculated by means of a stored transfer function UF as a function of the actual conveying capacity PF calculated in measure d). This volume flow V can be taken into account when controlling the conveying device 5 in connection with a brewing process in the brewing device 4 for preparing a coffee hot beverage.In the example scenario, a calibration of the heating device 6 is carried out taking into account the calibration of the conveying device carried out in the measures a) to d).In order to calibrate the heating device 6, three measures k 1), k 2) and k 3) are carried out one after the other according to FIG. 2. According to measure k 1), a predetermined setpoint heating power PH-S is set in heating device 6. In measure k2), a temperature TEMPor TEMP* of the water W conveyed through the water channel 3 by means of the conveying device 5 is measured both upstream and downstream of the heating device. In measure k3), a difference DIFF=TEMP-TEMP* of the two temperature values measured in measure k1) is determined. In addition, in measure k 3), an actual heating power PH of the heating device 6 is determined by comparing the difference DIFF with a stored reference difference DIFF-R. The execution of measure k3) is only started after temperature T measured downstream of heating device 6 has converged to a predetermined temperature limit value TEMP-G.Optionally, before performing measure k 1), the water channel 3 can be rinsed with water W at ambient temperature. The ambient temperature may be the initial temperature TEMP- 0 of the water W before heating.List of reference characters1 Coffee machine 2 Storage container 3 Water channel 4 Brewing device 5 Conveying device 6 Heating device 7 a, 7b first / second temperature sensor 8 storage unit 10 control / regulating device W water V volume flow UF transfer function PF-S setpoint delivery rate PH-S setpoint heating rate PF actual delivery rate PH actual heating rate T time duration T-REF reference time duration ΔT difference between the determined time duration T and the stored reference time duration T-REF T0 reference time duration TEMP-G temperature limit value TEMP-0 starting temperature DIFF difference DIFF-R reference difference TEMP temperature (downstream of the heating device) TEMP* temperature (upstream of the heating device) TEMP+ increased temperature TEMP-S temperature threshold value

Claims

Method for operating, in particular calibrating, a coffee machine (1) comprising the following measures: a) providing the coffee machine (1) comprising a storage container (2) for receiving water (W) which communicates with a brewing device (4) via a water channel (3) through which the water (W) can flow, wherein a conveying device (5) for conveying the water (W) from the storage container (2) into the brewing device (4) and a heating device (6) for heating the water (W) guided through the water channel (3) are arranged in the water channel (3), b) conveying water (W) from the storage container (2) through the water channel (3) into the brewing device (4) by means of a predetermined setpoint conveying power (PF-S) of the conveying device (5) set in the conveying device (5), wherein the water (W) guided through the water channel (3) is heated by setting a specific setpoint heating power (PH-S) for heating the water (W) in the heating device (6), c) determining that time duration (T) with the aid of a temperature sensor (7a) which has elapsed since the activation of the heating device (6) until a temperature increase (TEMP+) is detected in the conveyed water on the basis of the heating, d) Comparison of the determined time duration (T) with a stored reference time duration (T-REF) and determination of an actual conveying capacity (PF) of the conveying device (5) from this comparison.Method according to Claim 1, characterized in that - the temperature increase (TEMP+) with respect to the starting temperature TEMP-0 determined in measure c) can be arbitrarily small; or in that - the temperature increase (TEMP+) with respect to the starting temperature TEMP-0 determined in measure c) must have exceeded a predetermined threshold value TEMP-S.Method according to Claim 1 or 2, characterized in that the actual conveying capacity (PF) is determined as a function of a difference (ΔT) between the determined time duration (T) and the stored reference time duration (T-REF).Method according to one of Claims 1 to 3, characterized in that at least the time duration (T) determined in measure c) is stored in a memory unit (8) of the coffee machine (1).Method according to one of the preceding claims, characterized in that, as a function of the actual delivery rate (PF) calculated in measure d), a volume flow (V) of the water (W) through the water duct (3) is calculated by means of a stored transfer function (UF).Method according to one of the preceding claims, characterized in that a calibration of the heating device (6) is carried out taking into account the calibration of the conveying device (5) carried out in the measures a) to d).Method according to one of the preceding claims, characterized in that the following measures k1), k2), k3) are carried out for calibrating the heating device (6): k1) setting a predetermined setpoint heating power (PH-S) in the heating device (6), k2) measuring the temperature (TEMP, TEMP*) of the water (W) conveyed through the water duct (3) by means of the conveying device (5), both upstream and downstream of the heating device (6), k3) determining a difference (DIFF = TEMP-TEMP*) between the two temperature values (TEMP, TEMP*) measured in measure k2) and determining an actual heating power (PH) of the heating device (6) by comparing the difference (DIFF) with a stored reference difference (DIFF-R).Method according to Claim 7, characterized in that the action k3) is not started until the temperature (TEMP) measured downstream of the heating device (6) has converged to a predetermined limit value TEMP-G.Method according to Claim 7 or 8, characterized in that, before carrying out measure k1), the water duct (3) is rinsed with water (W) at ambient temperature.Coffee machine (1), in particular fully automatic coffee machine, - having a storage container (2) for receiving water (W) which communicates fluidically via a water channel (3) of the coffee machine (1) through which the water (W) can flow with a brewing device (4) of the coffee machine (1), wherein a conveying device (5) of the coffee machine with adjustable desired conveying capacity (PF-S) for conveying the water (W) from the storage container (2) into the brewing device (4) and a heating device (6) of the coffee machine with adjustable desired heating capacity (PH-S) for heating the water (W) guided through the water channel (3) are arranged in the water channel (3), - with a control / regulation device (10) for setting a setpoint conveying power (PF-S) in the conveying device (5) and for setting a setpoint heating power (PH-S) in the heating device (6), - wherein the control / regulation device (10) is set up / programmed for carrying out the method according to one of the preceding claims.Coffee machine (1) according to claim 10, characterised in that the coffee machine (1) comprises a first temperature sensor (7a) for measuring the temperature (TEMP) of the water (W) guided through the water channel (3) downstream of the heating device (6) and a second temperature sensor (7b) for measuring the temperature (TEMP*) of the water (W) upstream of the heating device (6), wherein preferably the two temperature sensors (7a, 7b) are connected to the control / regulation device (10) in a data-transmitting manner.Computer program product which contains instructions which, when the computer program product is executed by a computer system, cause this computer system and / or the control / regulation device (10) of the coffee machine (1) according to Claim 10 or 11 to carry out the method according to one of Claims 1 to 9.Data carrier containing commands which, when executed by a computer system and / or by the control / regulation device (10) of the coffee machine (1) according to claim 10 or 11, cause the computer system or the control / regulation device (10) to execute the method according to one of claims 1 to 9.

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