Method for operating a cleaning system for a cooking appliance

Abstract

Method for operating a cleaning system for a cooking appliance, comprising the following steps: - Water is introduced into a cleaning chemical reservoir (28) to rinse out a cleaning agent stored therein and to create a cleaning solution, - the chemical concentration in the generated cleaning solution is measured, - when the reservoir (28) is empty, an emptying process is started in which water is introduced into the reservoir (28) and the water exiting the reservoir (28) is analyzed to determine whether there are still residues of the cleaning agent in the water, If any cleaning agent residue is still detected, another emptying process is started. - if no residues of the cleaning agent are detected, the reservoir (28) is released for replacement.

Description

[0001] The invention relates to a method for operating a cleaning system for a cooking appliance, in which water is introduced into a cleaning chemical reservoir to rinse out a cleaning agent stored therein and to produce a cleaning solution.

[0002] The cooking appliance equipped with such a cleaning system is designed for professional use, such as in restaurants, canteens, and large-scale catering establishments. The cleaning system uses an automated cleaning program to clean the appliance. For this purpose, the system contains a supply of cleaning chemicals from which a cleaning solution can be prepared. This solution then circulates within the cooking appliance to achieve the desired cleaning effect. For example, the cooking chamber of the appliance can be cleaned and / or descaled, or a steam generator can be descaled.

[0003] The cleaning solution is generated by a cleaning chemical assembly, which includes a collection tank, a distributor, and usually several reservoirs containing the cleaning chemical. A pump draws water into specific reservoirs, dissolving and rinsing a portion of the cleaning chemical. This solution then flows back into the collection tank, where it is drawn in again and pumped to the reservoirs. Once the collection tank contains a cleaning solution with the desired concentration of cleaning chemical, it can be pumped either to a recirculation circuit within the cooking appliance for cleaning or descaling the cooking chamber, or to a steam generator for descaling.

[0004] Regarding the details of such a cleaning chemical assembly, reference is made to DE 10 2020 117 842 A1, which is fully referenced with regard to the design and operation of the cleaning chemical assembly.

[0005] When the cleaning agent in a reservoir is depleted, it should be replaced. This can be done by monitoring whether the concentration of cleaning agent in the cleaning solution changes as expected when water is pumped into a particular reservoir. If the concentration of cleaning agent changes less than expected, there will be very little cleaning agent left in the reservoir, and therefore very little cleaning agent can be rinsed out with the added water. A notification can then be displayed to the user indicating that the reservoir should be replaced with a new one. This is also described in EP 3 298 946 A1.

[0006] A disadvantage here is the risk that a user might replace the reservoir while it still contains traces of the cleaning agent. While this is theoretically possible, the user must then take special precautions to prevent contact with the cleaning agent.

[0007] German patent DE 10 2020 117 844 A1 discloses a cleaning chemical system comprising a collection container and a conductivity sensor arranged in the collection container. The water hardness of the liquid is determined based on a change in the conductivity of a liquid rinsed into the collection container.

[0008] DE 10 2020 117 841 A1 discloses a cleaning chemical assembly with storage containers containing different cleaning chemicals and a means for detecting the cleaning chemical in the respective storage container.

[0009] The object of the invention is to simplify the process of replacing an empty storage container.

[0010] To solve this problem, the invention provides a method for operating a cleaning system for a cooking appliance, comprising the following steps: When a cleaning agent stored in a cleaning chemical reservoir is to be rinsed out to produce a cleaning solution, water is introduced into the reservoir. The chemical concentration in the resulting cleaning solution is then measured. When the reservoir is empty, a draining process is initiated, during which water is introduced into the reservoir and the water exiting the reservoir is analyzed to determine whether any cleaning agent residues remain. If cleaning agent residues are detected, another draining process is initiated. If, however, no cleaning agent residues are detected, the reservoir is released for replacement.

[0011] The emptying process has the advantage of ensuring that the reservoir is completely empty and pH-neutral when a user replaces it. This eliminates any risk of the user coming into contact with the cleaning chemicals, and there is no need to take any special protective measures. The removed reservoir can then be recycled. It is not necessary to dispose of the reservoir (due to any potential residues of the cleaning chemicals) in the general waste. A further advantage of the method according to the invention is that the emptying process ensures that the reservoir is removed completely empty, while the cleaning chemical assembly remains fully functional at all times.The emptying process is initiated when a control system detects that the cleaning agent in the reservoir is running low, but a small amount of cleaning agent remains. This allows for the continuation of a cleaning solution, while still ensuring the reservoir can be safely removed after the emptying process is complete.

[0012] According to one embodiment of the inventive method, the emptying process is automatically started when the chemical concentration in the generated cleaning solution indicates that the reservoir is empty. "Empty" in this context means that the cleaning agent in the reservoir is so depleted that it takes an excessively long time to produce a cleaning solution with the desired concentration. The reservoir is therefore not yet so empty that no cleaning solution can be produced at all (and thus the cleaning chemical assembly would no longer function), but rather empty enough that replacing it with a new reservoir would be advisable. The emptying process can then be started without any external input. Once completed, the user is notified that a specific reservoir can now be replaced with a new one.

[0013] According to an alternative embodiment of the method according to the invention, the emptying process is initiated when a user indicates via a user interface that the reservoir should be replaced. This allows a user to continue using a nearly empty reservoir for a while longer, for example, if a replacement reservoir is not yet available, instead of having it automatically emptied and thus rendered unusable. Only when the replacement reservoir is available does the user initiate the emptying process to replace the then completely empty reservoir.

[0014] Preferably, a maximum number of emptying cycles is specified, with a warning signal being issued if residues of the cleaning agent are still detected after the last of the maximum specified emptying cycles. This prevents the emptying process from being repeated repeatedly in the event of a malfunction of the sensor that detects the chemical concentration in the water exiting the reservoir during emptying, even if the reservoir is already completely empty.

[0015] According to one embodiment, the same sensor used to monitor the generation of the cleaning solution is also used to detect cleaning agent residues. This results in a simpler design and lower costs for the cleaning chemical assembly.

[0016] Residues of the cleaning agent are preferably detected based on the measured conductivity of the water exiting the reservoir. This can be done with readily available sensors with minimal effort. Alternatively, a pH sensor can be used to detect whether any cleaning agent remains in the water exiting the reservoir during emptying.

[0017] The invention is explained below with reference to the accompanying drawings. These show: - Fig. 1 schematically a cooking appliance with a cleaning chemical assembly with which the method according to the invention can be carried out; - Fig. 2 a cross-section through the cleaning chemical assembly of Fig. 1; - Fig. 3 a longitudinal section along plane III-III of Fig. 1; and - Fig. 4 a flowchart of the method according to the invention.

[0018] In Fig. Figure 1 schematically shows a cooking appliance 10, which is used to cook food or dishes. The cooking appliance 10 is a device intended for professional use in restaurants, canteens, or large-scale catering establishments.

[0019] The cooking appliance 10 has a cooking chamber 12 into which the food to be cooked can be placed. There, it can be cooked in a cooking chamber atmosphere that is dry air, air with a controllable humidity level, or steam. It is also possible to introduce microwave radiation into the cooking chamber 10. The necessary components for this, such as a steam generator, heating element, circulation device, or microwave generator, are included in Fig. 1 not shown, as they are not necessary for understanding the invention.

[0020] Below the cooking chamber 12 is a cleaning box 14, which is connected to the floor of the cooking chamber 12 by a drain opening 16. Liquids, cooking residues, cleaning solution (the so-called washing liquor), etc., flow from the cooking chamber 12 into the cleaning box 14 through the drain opening 16.

[0021] The contents of the cleaning box 14 can be pumped (not shown) to a wastewater outlet 18 when the cleaning box 14 needs to be emptied. Alternatively, the contents of the cleaning box 14 can be pumped into the cooking chamber 12 via a circulation pump 20, from where they return to the cleaning box 14. This circulation is used to clean the cooking chamber by circulating a cleaning solution through the chamber 12 until it is clean.

[0022] For safety reasons, a free overflow is also provided, but it is not visible here.

[0023] A cleaning chemical assembly 22 is provided to supply the cleaning solution. For details of the assembly, full reference is made to the contents of DE 10 2020 117 842 A1.

[0024] In general terms, the cleaning chemical assembly 22 comprises a collection container 24, a distributor 26, and several storage containers 28 for cleaning chemicals. Water can be supplied via a fresh water connection 29.

[0025] A pump 30 is used to spray water from the collection container 24 into the storage containers 28, causing some of the cleaning chemicals contained therein to dissolve and flow into the collection container 24. The process of rinsing the cleaning chemicals from the storage containers 28 is continued until the desired concentration of cleaning chemicals is reached in the collection container 24.

[0026] This is detected by a sensor 40, which provides a signal about the chemical concentration in the cleaning solution to a controller (not shown here). This signal can be the conductivity of the cleaning solution. The pH value of the cleaning solution can also be detected.

[0027] The water level remaining in distributor 26 and in collection tank 24 when pump 30 is switched off is indicated here by reference numeral 41.

[0028] The cleaning chemical, once prepared at the desired concentration, can be pumped into the cleaning box via line 32 if it is a cleaning solution, or to a steam generator via line 34 if it is a descaling fluid.

[0029] The function of the distributor 26 is to direct the solution supplied by the pump 30 either to one or more of the storage containers 28 for cleaning chemicals or to open the outlets to the lines 32, 34 by means of various valves.

[0030] The corresponding valves are in the Fig. 2 and Fig. 3 with the reference number 36.

[0031] If water is sprayed into reservoir 28 to rinse out cleaning agents, but the concentration of cleaning chemicals in the cleaning solution does not increase at the expected rate, this is an indication that the corresponding reservoir 28 is nearly empty.

[0032] Step S1 in Fig. 4 symbolizes that the control system of the cooking appliance detects that the concentration of cleaning chemicals in the cleaning solution is not increasing as quickly as expected.

[0033] If this is the case, an emptying process is initiated for the corresponding reservoir 28 (step S2). The emptying process consists of spraying water into the corresponding reservoir for a predetermined duration or spraying a predetermined volume of water into the reservoir to remove any remaining cleaning chemicals from reservoir 28. Simultaneously, the chemical concentration in the water collected in collection tank 24 is measured. The same sensor 40 used to measure the concentration of the cleaning chemicals can be used for this purpose.

[0034] In step S3, the signal is evaluated via the chemical concentration to determine whether the water in the collection container 24 is free of cleaning chemicals.

[0035] If this is the case (branch J), it is a reliable indicator that the storage container 28 is completely empty. A display on the cooking appliance can then inform the user that the corresponding storage container can now be safely removed. Recycling information can also be displayed.

[0036] If the detected signal indicates that there is still cleaning chemical in the water (branch N after step S3), step S2 is repeated, i.e., water is sprayed into the corresponding reservoir again to empty it completely.

[0037] This loop is repeated until either the reservoir is completely emptied or a termination criterion is reached, in particular a predefined maximum number of emptying operations. In this case, a warning message may be issued advising the user to exercise particular caution when replacing reservoir 28.

Claims

[1] A method for operating a cleaning system for a cooking appliance, comprising the following steps: - water is introduced into a cleaning chemical storage container (28) in order to rinse out a cleaning agent stored there and to produce a cleaning solution, - the chemical concentration in the cleaning solution produced is measured, - when the storage container (28) is empty, an emptying process is started in which water is introduced into the storage container (28) and the water leaving the storage container (28) is analyzed to determine whether residues of the cleaning agent are still present in the water, - if residues of the cleaning agent are still detected, another emptying process is started, - If no residues of the cleaning agent are detected, the storage container (28) is released for replacement. [2] Method according to claim 1, characterized bythat the emptying process is started automatically when the chemical concentration in the cleaning solution produced detects that the storage container (28) is empty. [3] Method according to claim 1, characterized by that the emptying process is started when a user inputs via a user interface that the storage container (28) should be replaced. [4] Method according to one of the preceding claims, characterized by that a maximum number of emptying cycles is specified and a warning signal is issued if residues of the cleaning agent are still detected after the last of the maximum number of emptying cycles provided. [5] Method according to one of the preceding claims, characterized by that the same sensor (40) is used to detect residues of the cleaning agent as is used to monitor the production of the cleaning solution. [6] Method according to one of the preceding claims, characterized by that residues of the cleaning agent are detected on the basis of the determined chemical concentration in the water leaving the storage container (28). [7] Method according to one of the preceding claims, characterized by that the chemical concentration is recorded by measuring the conductivity. [8] Method according to one of claims 1 to 6, characterized by that the chemical concentration is determined by measuring the pH value.

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