Method for cleaning / descaling a hot beverage maker and hot beverage maker for carrying out the method

Abstract

The invention relates to a method for cleaning and / or descaling a hot beverage maker, comprising the following steps: a) detecting an activation request for the cleaning and / or descaling method on the hot beverage maker (I), b) detecting a user input regarding the cleaning and / or descaling method (II), and c) executing a cleaning / descaling program associated with the user input (IV), characterized in that the user input consists in specifying the cleaning / descaling agent to be used. The invention also relates to a corresponding hot beverage maker (1) for carrying out the method according to the invention.

Description

[0001] The invention relates to a method for cleaning and / or descaling a hot beverage maker, comprising the following steps: a) activating the cleaning and / or descaling method on the device, b) detecting a user input regarding the cleaning and / or descaling method, and c) executing a cleaning / descaling program associated with the user input. The invention also relates to a corresponding hot beverage maker with an activation unit, an input unit, and a control unit, in particular a fully automatic coffee machine or a capsule machine, preferably for household purposes.

[0002] DE 20 2013 012 459 U1 describes a cleaning system for a cooking appliance with a combi steamer, in which the operator can change several parameters of a cleaning parameter set. This requires a high level of operator expertise.

[0003] From DE 10 2011 081 010 A1 a beverage dispenser with a cleaning device for carrying out a cleaning and / or descaling process is known.

[0004] The invention is based on the object of providing an improved method for cleaning and / or descaling a hot beverage maker and a corresponding hot beverage maker for carrying out the method, whereby a more efficient use of active ingredients and / or a faster execution of the service process is possible.

[0005] The invention achieves this object in the above-mentioned method in that the user input consists in specifying the cleaning and / or descaling agent to be used and the cleaning / descaling program is carried out according to the user input.

[0006] Most hot beverage makers have a pre-set and factory-set cleaning and / or descaling program. A cleaning program can be used, in particular, to free all fluid paths of the hot beverage maker from deposits that accrue during coffee preparation, such as grease, oil, solids, as well as mold spores, germs, and bacteria. Alternatively or additionally, a descaling program can be used to remove water-insoluble limescale deposits that form in tap water at elevated temperatures. The cleaning program and the descaling program can be selected and run individually or together. If one or both of the programs are referred to below without a specific distinction, they are collectively referred to as the service program or service procedure.

[0007] The service program for a hot beverage maker is usually designed and specified for each machine. Furthermore, the user of the hot beverage maker is not always free to choose a cleaning or descaling agent in terms of manufacturer, form (solid or liquid), concentration, and chemical composition. However, failure to follow the manufacturer's specifications may result in suboptimal results, depending on the agent used. Using unsuitable agents can cause long-term damage to the hot beverage maker, for example, through metal corrosion or damage to seals.

[0008] The inventive method comprises steps a) to c), which are carried out in the hot beverage maker. It is also referred to below as a 'hot beverage device' or, for simplicity, as a 'device'.

[0009] Activating the cleaning and / or descaling process on the hot beverage maker in step a) is done in a conventional manner after switching on the hot beverage maker by selecting and entering a menu or by pressing or turning a corresponding button. Acoustic activation is also possible. The device's menu can also be accessed remotely, for example, using an application on a smartphone wirelessly connected to the device ("app").

[0010] According to the invention, the user input recorded in step b) does not consist of specific parameter values, but rather of the cleaning / descaling agent intended for the immediately following service procedure. The user therefore only needs to specify the product they have selected for the service program. The user does not need any technical knowledge, especially process engineering, to do this, but still receives optimal results from the subsequent service program.

[0011] This means, for example, that the user doesn't have to adjust the mixing ratio themselves or extend the contact time if they use a weaker cleaning / descaling agent than recommended. Instead, the device automatically sets all necessary and / or favorable parameters using the parameters pre-stored for the selected product, ensuring the process is not only efficient but also as environmentally friendly as possible.

[0012] To make it easier for the user to select the desired cleaning / descaling agent, after switching on the device and accessing the "Clean / Descale" menu item, a display unit on the device can provide a selection of various cleaning / descaling agents, allowing the user to simply select the desired agent. Once the user has selected the cleaning / descaling agent they want to use from the displayed list, they can confirm their selection, for example, by starting the program.

[0013] Instead of selecting from a playback, the user can alternatively enter an identification code for the selected cleaning / descaling agent. The input can be made manually or acoustically. Alternatively, the input can be simplified for the user through machine assistance, for example, visually through object, font, barcode, or QR code recognition. Recognition can be camera-based, with the camera or a scanner being used on the device or in a smartphone application (“app”). Alternatively, it can be done wirelessly, for example by detecting an NFC or other RFID code, again by the hot beverage device itself or in an app.

[0014] In step c), the device now executes the service program based on the information about the product that the user has selected for the service program.

[0015] In general, a service program follows a standard procedure and is essentially divided into three main process steps: "dissolving / diluting," "allowing to take effect," and "rinsing." The "dissolving / diluting" process can take different lengths of time depending on the state of the cleaning / descaling agent, particularly the degree of compression or grain size of solid agents, or the concentration of liquid agents. The "allowing to take effect" process serves to dissolve dirt or limescale deposits and lasts for different lengths of time depending on the effectiveness of the agent. During "rinsing," the dissolved contaminants and the agents used to remove them are flushed out of the fluid paths. Parameters for carrying out the procedure can be assigned to each process step.

[0016] According to an advantageous embodiment of the invention, after specifying the cleaning / descaling agent to be used in step b), the device calls up a specific parameter set for executing a service program. The parameter set is assigned to the cleaning / descaling agent selected and to be used by the user and relates, for example, to the dissolution time, the concentration to be achieved, the contact time of the cleaning / descaling agent, the flow time of a cleaning / descaling solution, its temperature, the amount of water to be used for rinsing, or other parameters relevant to the execution of the service program.

[0017] The specific parameter set is called up on the device side from a parameter memory in which the service program parameters individually linked to the respective cleaning / descaling agent have been stored at the factory. This eliminates the need for the user to adjust the service program to the agent used, which would often be overwhelming. Instead, the hot beverage machine provides the parameters that promise the best cleaning and / or descaling results with the respective agent. The manufacturer has previously determined and stored the parameters for each cleaning / descaling agent through series of tests.

[0018] For a third-party product, a standard parameter set consisting of generously selected parameters can be stored on the device. However, to enable efficient execution of the service program, the hot beverage maker can initiate a more detailed query regarding the properties of a third-party product when the user selects a third-party product, for example, its dosage form as a tablet, powder, or liquid. This can then be followed by a query regarding the quantity, for example, in grams or milliliters, etc. Suitable parameters can then be assigned to the information obtained from the third-party product, allowing a customized and suitable parameter set to be compiled for the third-party product on the device.

[0019] If a user input indicates an unsuitable cleaning / descaling agent, the device can display a corresponding warning for protection. For example, if a user wants to use pure citric acid in liquid form, the device can display the message: "Use is not recommended for this device."

[0020] Advantageously, the parameter set called up by a device's control unit for a specific cleaning / descaling agent can differ in only one parameter—such as the contact time—from a parameter set available for another selectable cleaning / descaling agent. This can result in a certain amount of time savings, as adjusting just one parameter by the device is straightforward and doesn't take long.

[0021] If the cleaning / descaling agent is known to the device, a total duration for the service program to be performed in step c) can usually be displayed during the display. Otherwise, with other selection procedures, e.g., with the above-mentioned code capture or similar, and particularly with third-party products, according to a further advantageous embodiment, a total duration for the service program to be performed in step c) can be displayed after the selection and specification of a cleaning / descaling agent in step b) or after a possible detailed specification of its properties. Thus, the total duration of process step c) is determined by the recorded user input in step b). Thus, after specifying the cleaning / descaling agent to be used, the user is shown a possibly modified total duration on the device. This provides the user with information as to when the device will be available again for beverage preparation.

[0022] The total duration can be displayed directly on the playback unit, e.g., a display, and appear immediately after specifying the cleaning / descaling agent to be used. Alternatively, or additionally, the total duration can be displayed in the app in which the cleaning / descaling agent to be used was entered.

[0023] Advantageously, step c) is only carried out when the selected cleaning / descaling agent is confirmed again by a user input after its total duration has been displayed.

[0024] Based on the total duration displayed, the user can decide which cleaning / descaling agent to use – possibly during a later service. If the total duration displayed seems too long, they can select a different product.

[0025] As a further variant, the user can first specify a desired duration for the service program, following which one or more suitable cleaning / descaling agents are suggested. The duration can be specified as a maximum duration, i.e., the maximum time available. This variant is particularly advantageous prior to a purchasing decision, when a limited time window available for completing the service program should serve as the basis for the purchase decision for the cleaning / descaling agent.

[0026] According to a further advantageous embodiment, this information can be accessed via a smartphone application (“app”). The user can then make their decision about the cleaning / descaling agent to purchase from a location separate from the hot beverage maker, for example, directly during the purchase.

[0027] According to a further advantageous embodiment, step c) above is followed by step d), in which the descaling performance of the current service process is detected, stored if necessary, compared with an expected result, and a display corresponding to the result of the comparison is output. Such a step d) occurs in particular if a third-party product, e.g., designated as "Other" on the display, was selected in step b). This has the advantage that the user can directly read the efficiency of the product unknown to the device after the service program has been completed.

[0028] Programs for detecting the descaling performance are known from EP 2 080 461 B1, DE 10 2019 217 640 A1 and EP 4 033 161 A1.

[0029] According to a further advantageous embodiment, after the descaling performance has been detected and, if necessary, saved, it is compared with an expected result, and in a corresponding subsequent service procedure, at least one parameter of the procedure is adjusted depending on the comparison. In this embodiment, the device "learns" the actual descaling performance of a cleaning / descaling agent. The device uses a predefined standard set of parameter values to perform the service procedure for the first time and, in a subsequent procedure using the same cleaning / descaling agent, adjusts one or more parameters of the service procedure so that an optimal service result is achieved for the device.

[0030] A deviation from the expected result may arise from the fact that a third-party product was used as a cleaning / descaling agent which is not known to the manufacturer, for which no parameter values have been determined and which is therefore not suggested by the device.

[0031] This means that even unknown cleaning / descaling agents can be used with the greatest possible safety against damage to the device.

[0032] Deviations from the expected result can also arise when selecting a known cleaning / descaling agent due to environmental or other conditions unexpected by the manufacturer or not taken into account by the device, for example, due to water hardness that deviates significantly from the usual, an unusual water temperature, a change in the formulation of the cleaning / descaling agent, or the absolute altitude of the device's installation location above sea level. Such changes can therefore also be detected and taken into account according to the invention. Environmental aspects such as water and electricity consumption can also be considered.

[0033] In any case, the user doesn't have to make any adjustments, so no expertise is required if they want to use a new cleaning / descaling agent of their choice or to accommodate different conditions. Rather, the device automatically optimizes its service program to ensure efficient descaling and prevent damage to seals or similar components in the device.

[0034] Advantageously, step d) for detecting the descaling performance can only be performed when a third-party product is selected or specified. A third-party product is a cleaning / descaling agent that the hot beverage maker is unfamiliar with and therefore does not automatically suggest. If the descaling performance is only performed when performing the service procedure with a third-party product, the program sequence can be shortened, at least for the device, even if the user may not gain any time as a result.

[0035] According to a further advantageous embodiment, the parameter that is adjusted depending on a comparison of the achieved or expected descaling performance in a corresponding subsequent process can be, for example, the mixing ratio of cleaning / descaling agent to water in the "dissolving / diluting" process step, the exposure time of the cleaning / descaling solution in the "allowing to act" process step, the temperature of the acting cleaning / descaling solution, and / or a service interval. If, for example, the descaling performance is poorer than expected, the mixing ratio can be adjusted so that the concentration of descaling agent is higher. Likewise, the mixing ratio can be maintained and the exposure time selected to be longer.An increase in temperature can also lead to an increase in descaling performance, so that an adjustment of just one of the parameters leads to an adjustment of the overall descaling performance; adjusting several parameters simultaneously can have both an additive and synergistic effect on the descaling performance.

[0036] If all of the above-mentioned parameters are to be maintained, the time interval between descaling with the detected descaling performance and the subsequent descaling process can also be shortened or extended. For example, if the descaling performance was rated as unexpectedly good, increasing the time interval until the next descaling can save not only descaling agent but also water and energy.

[0037] The object underlying the invention is also achieved by a hot beverage maker with an activation unit, an input unit, and a control unit. According to the invention, the hot beverage maker comprises a memory unit containing a link between cleaning / descaling agents and associated service programs or parameter sets that define the respective service programs. The hot beverage maker is suitable for carrying out the above-mentioned method.

[0038] The hot beverage maker is used for the automatic preparation of hot beverages, for example, as a fully automatic coffee machine or as a capsule or pod coffee machine, preferably for domestic use. Especially for users with little or no technical, particularly process-related, knowledge, it is extremely advantageous if the hot beverage maker offers a link between specific cleaning / descaling agents and corresponding service programs, allowing for optimal service processes simply by specifying the respective cleaning / descaling agent.

[0039] The activation unit of a hot beverage maker is generally a device for activating the appliance, for example, by pressing, turning, touching, or by an acoustic signal. Activation via an external device, such as a smartphone application ("app"), is also possible.

[0040] The input unit can be designed in a variety of ways and includes a user interface through which a user can make an input. The input can be made via a device-side user interface, for example with buttons and / or a touchscreen. Alternatively or additionally, the user's selection and input can be possible via an external or remote control panel, such as an application on a smartphone ("app") or other mobile device, or via an acoustic signal. Alternatively, the hot beverage device can be equipped with a camera or scanner or a device for capturing an NFC or other RFID code in order to capture user input regarding the selection of the cleaning / descaling agent.

[0041] The user interface may also include a display unit that, for example, presents the user with various cleaning / descaling agents on the device and allows them to choose between them, so that the user only needs to select the desired agent.

[0042] The information can be visual, written, or audible. Users can choose from either proprietary brand cleaning / descaling agents or those from other manufacturers. These can be solid products in tablet or powder form, or liquid cleaning / descaling agents.

[0043] The control unit is a central component of the computer located in the hot appliance and controls all functions such as the heating processes or the water feed, pumping and dispensing processes and all other processes of the preparation and service programs.

[0044] According to the invention, the hot beverage maker comprises a memory unit containing a link between cleaning / descaling agents and associated service programs. The memory unit contains a specific parameter set for executing a service program, which is linked to a selectable cleaning / descaling agent. The parameter set is therefore assigned to the selected cleaning / descaling agent to be used and relates, for example, to the dissolution time, the concentration, the exposure time, the flow time, the temperature, the amount of water flushed, or other parameters relevant to executing the service program. This makes it possible for the first time to carry out a method as described above, in which a specific cleaning / descaling program (service program) is executed depending on a selected cleaning / descaling agent, without the user having to make any further settings themselves.

[0045] According to a further advantageous embodiment, the input unit of the hot beverage maker comprises a user interface in which, with the aid of the aforementioned display unit, various cleaning / descaling agents can be displayed for user selection. The display can be provided, for example, in written and / or graphic form. This makes it particularly easy for the user to have the hot beverage maker perform a service program suitable for the cleaning / descaling agent, since they only need to select one from the displays.

[0046] According to a further advantageous embodiment, the hot beverage maker comprises a device for detecting the descaling performance, as described, for example, in EP 2 080 461 B1, DE 10 2019 217 640 A1, or EP 4 033 161 A1. In this device, a calcification status is determined either based on changing temperature differences or based on changing temporal behavior, e.g., an increased duration until a certain temperature value is reached. The hot beverage maker also has a comparison unit in which the detected descaling performance is compared with an expected descaling performance, and the result of the comparison is processed for a subsequent descaling process. Based on the result of the comparison, the control unit adjusts the parameters for a subsequent descaling process and saves them.

[0047] The device can thus determine the descaling performance of a third-party product by detecting the degree of descaling and comparing this value with, for example, a previously saved standard value. This allows the effectiveness of the third-party product to be determined and, upon reuse, leads to the desired result. The data determined for the third-party product can be marked and saved by the user so that it can be accessed in a later process.

[0048] The invention effectively optimizes cleaning and descaling performance by adapting it to the cleaning / descaling agent used, thereby potentially shortening the duration of the cleaning / descaling process. Due to the improved cleaning and descaling performance, the lifespan of a hot beverage maker is extended and the environment is protected.

[0049] The principle of the invention is explained in more detail below using a drawing as an example. The drawing shows: Fig. 1: a flowchart of a first method according to the invention, Fig. 2: a flowchart of a second method according to the invention, and Fig. 3: a schematic structure of a hot beverage maker according to the invention

[0050] Fig. 1 shows a flowchart of the method according to the invention, in which a user selects a cleaning / descaling agent from a series of products known to the device.

[0051] First, the user turns on the device using a start button on the device or another switching device. After starting up the device, the user accesses the "Clean / Descale" menu item in step 1, which activates the service procedure. This can be done, for example, by pressing a corresponding button or key.

[0052] A user interface on the device then uses a display unit in step 1a to display various cleaning / descaling agents known to the device and available for selection. The selection can be continually expanded to include new products via software updates. It also offers an option for unknown cleaning / descaling agents, labeled, for example, 'Other'. The known cleaning / descaling agents can be the device manufacturer's own products or products from other manufacturers. For the known cleaning / descaling agents, suitable parameters were stored in the device through prior test series; these parameters determine a process sequence for cleaning and / or descaling the device.

[0053] The display can, for example, consist of images of known products and their names. The user then selects one of the displayed cleaning / descaling agents by making an input on the device's user interface in step II, for example, by touching a touch-sensitive screen of the user interface.

[0054] The display unit then displays the total duration of the service program stored for this selected product in step IIa. Based on this information, the user can adjust their current or future cleaning / descaling agent selection.

[0055] If the user agrees with the displayed time period, he confirms his entry from step II by entering it again in step III, for example by touching the touchscreen again at the point of his choice.

[0056] If the user does not agree with the total duration displayed in step IIa and does not confirm the input made in step II, the device returns to step la after a defined period of time, for example 5 seconds, and again displays the cleaning / descaling agents available for selection, including the option for 'Other'.

[0057] Once the user has made their selection and specified it in step III, the hot beverage maker then automatically executes the service program corresponding to the selected cleaning / descaling agent in step IV, using the parameters stored in the device. The user does not need to perform any further steps, because by selecting the cleaning / descaling agent, they have already indirectly communicated to the device the parameters for executing the service program that are expected to achieve optimal service results based on the selected cleaning / descaling agent.

[0058] Once the service procedure is complete, the appliance prompts the user to perform service activities such as emptying a residual water tray and / or rinsing a water reservoir and then either switches itself off immediately or returns to a standby mode for a certain period of time.

[0059] Fig. 2 shows a flowchart of a method according to the invention in which a user wishes to use a cleaning / descaling agent unknown to the device.

[0060] As in the procedure described above with reference to Fig. 1, the user switches on the device and activates the service program 'Clean / Descale' in step I in the device menu.

[0061] As after Fig. 1, various cleaning / descaling agents are then displayed in step 1a. These can be either the manufacturer's own products or products from other manufacturers, for which parameters have been stored in the device through prior testing. An option for unknown third-party products for which no specific parameters have yet been stored is also displayed, for example, displayed as 'Other'.

[0062] If the user now selects the option 'Other' and makes the corresponding entry in step II, a parameter check is carried out in step IIIb to determine whether the parameter memory already contains values or data from a previous procedure with a third-party product.

[0063] If the parameter memory indicates no ("-"), the device executes a service program in step IV using default parameters stored in the device for this case. These are set at the factory based on tests.

[0064] In the following step V, the descaling performance of the last service program carried out is determined using a program for recording the descaling performance and in step VI it is compared with a predefined service result in a comparison unit.

[0065] If the comparison in step VI shows that the descaling performance was OK (symbol “+”), the standard parameters that were used for the third-party product in the service procedure are left unchanged and stored for the use of the next third-party product.

[0066] If the comparison in step VI reveals that the descaling performance was insufficient, i.e., worse (symbol "-"), the applied standard parameters are adjusted in step VII, and the adjusted parameters are stored in memory for the next use of a third-party product. A third-party product can also be individually saved together with the associated, adjusted process, so that the third-party product is recognized during subsequent use, resulting in a customized device setting.

[0067] Once the service procedure is complete, the device prompts the user to perform service activities such as emptying a residual water tray and / or rinsing a water reservoir and then either switches itself off immediately or goes into standby mode for a certain period of time.

[0068] If, however, it is determined in step IIIb that values from a previous procedure with a third-party product are already available ("+"), these values are retrieved from memory in step IIIc, and the service procedure is carried out in step IV using the stored parameter values. Optionally (not shown), the descaling performance can also be determined in step V using a program for recording the descaling performance. In step VI, this can be compared with a previously defined service result. The parameter values used can be adjusted and then saved if necessary.

[0069] After the device has performed the service procedure in step IV, the device prompts the user to perform service activities such as emptying a residual water tray and / or rinsing a water reservoir and then either switches itself off directly or goes into standby mode for a certain period of time.

[0070] Fig. 3 shows a schematic structure of a hot beverage maker 1 according to the invention as a coffee machine, which is suitable for carrying out the method according to the invention.

[0071] The coffee machine has a touch-sensitive screen 6, on which touch-sensitive fields are displayed, represented as buttons 5 and 7. The start button 5, which turns on the coffee machine 1, is located on the far left edge as the beginning of a row of selection buttons 7 on the right.

[0072] The screen 6 also includes a rectangular display field 8, which, after the device is switched on, displays several cleaning / descaling agents available to the user in the form of product images and / or in words. Below the display field 8, the screen 6 contains touch-sensitive fields 7 configured as buttons, which can be used to select and confirm one of the cleaning / descaling agents shown in the display 8.

[0073] The coffee machine 1 has a computing unit 2 inside and includes a memory unit 3 in which, among other things, the parameters are stored. The computing unit 2 further includes a comparison unit in which measured values are compared with predetermined values, and a device for detecting the descaling performance (both not shown), which is connected to the comparison unit.

[0074] The coffee machine 1 also includes a control unit 4. The control unit 4 is a central component of the computer located in the coffee machine and controls all functions and processes of the preparation and service programs.

[0075] Since the above-described embodiments are examples, they can be modified to a wide extent by those skilled in the art in the usual way without departing from the scope of the invention. In particular, for example, a descaling performance can also be recorded for cleaning / descaling agents known to the device in order to record product or recipe changes and adjust the parameters accordingly, or the arrangement of operating elements can be designed in a different form if this is necessary for reasons of space or design. Furthermore, the use of the indefinite article "a" or "an" does not exclude the possibility that the features in question can also be present multiple times or multiple times. List of reference symbols I Activation of the service procedure Ia Display cleaning / descaling agent II Input by user IIa Display total duration III Confirmation by user IIIa no confirmation by user IIIb Checking whether values from previous procedures are available Illc Retrieving values IV Execution of service program V Detection of descaling performance VI Comparison of descaling performance values VII Changing parameter values 1 coffee machine as hot drink maker 2 computing unit 3 storage unit 4 Control unit 5 Start button 6 screen 7 selection buttons 8 Display field

Claims

[1] Method for cleaning and / or descaling a hot beverage maker, comprising the steps: a) detecting an activation request for the cleaning and / or descaling procedure on the hot beverage maker (I), b) Recording a user input regarding the cleaning and / or descaling procedure (II), c) Executing a cleaning / descaling program assigned to the user input (II) (IV), characterized by that the user input (II) consists in specifying the cleaning / descaling agent to be used. [2] Method according to claim 1, characterized by that after specifying the cleaning / descaling agent to be used (II), a specific set of parameters for the selected cleaning / descaling agent is called up by the device for implementation in step c). [3] Method according to one of the above claims, characterized bythat the process step c) is determined and displayed with regard to its total duration by the recorded user input (II) in step b). [4] Method according to one of the above claims, characterized by that after step c) in a step d) the descaling performance is detected, stored, compared with an expected result (V, VI) and a corresponding display is output. [5] Method according to one of the above claims, characterized by that after step c) in a step d) the descaling performance is detected, stored, compared with an expected result (V, VI) and in a corresponding subsequent cleaning / descaling process at least one parameter of the process is adapted depending on the comparison (VII). [6] Method according to claim 5, characterized by that the parameters are a mixing ratio, an exposure time, a temperature and / or a descaling interval. [7] Hot beverage maker (1) with an activation unit (5), an input unit (7) and a control unit (4), characterized by that the hot beverage maker comprises a storage unit (3) containing a link between cleaning / descaling agents and associated cleaning / descaling programs for carrying out a method according to one of the above claims. [8] Hot beverage maker according to claim 7, characterized by that it is a fully automatic coffee machine or a capsule machine. [9] Hot beverage maker according to claim 7 or 8, characterized by that the input unit (7) comprises a user interface in which various cleaning / descaling agents can be displayed for user selection. [10] Hot beverage maker according to one of claims 7 to 9, characterized bya device for detecting the descaling performance and a comparison unit in which the detected descaling performance is compared with an expected descaling performance and the result of the comparison can be retrieved and processed for a subsequent descaling process.

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