household appliance

Abstract

A domestic appliance (100) is provided with a storage container (110) having a first upper end (111), a second lower end (112), and a wall (113). The domestic appliance (100) has an electric heating unit (120) inside the container (110), a first temperature sensor (160) on the outside of the wall (113), a second temperature sensor (132) in a protective tube (130) in the area of ​​the electric heating unit (120), and a limescale detection unit (140) which is suitable for comparing the temperature readings of the first and second temperature sensors (160, 161, 131, 132) in order to detect a temperature difference and compare it with a target value in order to detect limescale buildup.

Description

[0001] The present invention relates to a household appliance and a limescale detection method for a household appliance.

[0002] It is common to find household appliances that heat water within a storage tank. When the water in this tank is heated, limescale can form on an electric heating element.

[0003] DE 10 2004 014 024 A1 describes a method for detecting limescale buildup in an electric radiator. The hot radiator is switched off and connected to a measuring bridge. As the radiator cools down, the voltage drop across it is measured and compared with a reference voltage curve to determine whether the radiator is scaled up.

[0004] DE 10 2010 002 438 A1 describes a descaling method using two temperature sensors in a hot beverage preparation appliance. A first temperature sensor is located directly at the heating element, and a second temperature sensor is positioned at the outlet. The temperature difference between the two sensors is measured and compared to a target value. If the temperature difference exceeds the target value, a signal indicates that limescale has formed.

[0005] EP 0 683 633 B1 describes a limescale detection method for water-generating appliances. A temperature sensor is provided on a pipe between a heat generator and a heat consumer. This sensor repeatedly measures the temperature of the heated water in the hot water pipe and compares it to an initial temperature value that corresponds to that of a non-limescaled heating unit. If a differential threshold is exceeded, limescale buildup in the appliance is indicated.

[0006] It is an object of the present invention to provide a skin technology device and a calcification detection method which enables simple and robust calcification detection.

[0007] This task is solved by a household appliance according to claim 1 and by a limescale detection method according to claim 5.

[0008] Thus, a domestic heating appliance is provided with a storage tank and an electric heating unit inside the tank. The electric heating unit heats the water in the storage tank. A first temperature sensor is located on the outside of the tank and measures its temperature. A second temperature sensor is located in a protective tube near the heating unit and measures the temperature of the water inside the storage tank. Furthermore, a limescale detection unit is provided, which records the temperature measured by the first and second temperature sensors and calculates the temperature difference to determine the degree of limescale buildup in the heating element.

[0009] This allows the calcification status of a household appliance to be determined without the need for additional sensors.

[0010] According to one aspect of the present invention, the second temperature sensor is provided in a safety temperature limiter protective tube containing a safety temperature limiter. This allows the second temperature sensor to be easily integrated into an existing protective tube of the safety temperature limiter. This is advantageous because it eliminates the need to modify the design of the building services device. Optionally, a second temperature sensor can be retrofitted into a protective tube of the safety temperature limiter.

[0011] The first temperature sensor can be designed as an integral sensor on the wall or as a dome temperature sensor.

[0012] According to one aspect of the present invention, the first temperature sensor is designed as an integral sensor, which is arranged on a wall of the container. Thus, for the implementation of limescale detection, only a second temperature sensor needs to be integrated into the protective tube. The first temperature sensor, namely the integral sensor, is typically already provided in domestic hot water preparation appliances.

[0013] According to one aspect of the present invention, the storage container has a dome. A dome sensor is provided in the area of ​​the dome as part of the first temperature sensor. Optionally, the dome sensor can be used as a temperature sensor for limescale detection.

[0014] The protective tube of the safety temperature limiter, along with the safety temperature limiter and the second temperature sensor, can be integrated into or onto a heating flange with an electric heating element. The heating flange can be integrated at the bottom of the container. Therefore, only one component, namely the heating flange, along with the protective tube and the temperature sensors, needs to be installed.

[0015] The container has a first upper end and a second lower end, as well as a cylindrical wall. Furthermore, it has a cold water inlet and a hot water outlet.

[0016] The invention also relates to a limescale detection method in which the temperature of the container wall is measured. Furthermore, in the area of ​​a heating unit within a protective tube for a safety temperature limiter, a second temperature sensor measures the temperature.

[0017] Further embodiments of the invention are the subject of the dependent claims.

[0018] The advantages and embodiments of the invention are explained in more detail below with reference to the drawing. Fig. Figure 1 shows a schematic representation of a household appliance.

[0019] Fig. Figure 1 shows a schematic representation of a domestic appliance. The domestic appliance 100 has a container 110 with an upper end 111, a lower end 112, and a substantially cylindrical wall 113. Furthermore, the container 110 has a cold water inlet 114 and a hot water outlet 115. An opening is provided at the lower end 112 through which a heating flange 120 can be inserted and watertightly attached. The heating flange 120 has at least one heating element 121 and a pipe 130 for accommodating a temperature sensor 132 and the safety temperature limiter 131.

[0020] A first temperature sensor 160, for example in the form of an integrated sensor, is provided on the outside of the wall 113 of the container 110. The first temperature sensor 160 can have a dome sensor 161 in the area of ​​the upper end, namely the dome 111, of the container 110.

[0021] The output signals of the first and second temperature sensors 160 and 132 are analyzed in a scale detection unit 140 to detect scale buildup on the electric heating element 121. Specifically, the scale detection unit 140 is designed to determine the temperature difference between the readings of the second temperature sensor 132 and the readings of the first temperature sensor 160. Since the second temperature sensor 132 is located near the electric heating element 121, the temperature it detects will be higher than the temperature at the wall 113 of the container, which is detected by the first temperature sensor 160. The temperature difference determined by the scale detection unit 140 can be compared to a target value. For example, scale buildup can be indicated if the target value is exceeded.

[0022] The household appliance 100 can also have a control unit 150 with a display that can provide a warning about possible limescale buildup. This warning can be visual and audible.

[0023] Optionally, the limescale detection unit can have a wireless transmitter, so that the limescale information can be wirelessly transmitted to a smartphone, for example.

[0024] If limescale buildup or impending limescale buildup is detected in the heating unit, the limescale detection unit 140 can intervene in the operation of the heating unit 120 and reduce the user-selected setpoint for the water temperature at the water outlet 115 or the water temperature in the appliance. This is particularly advantageous because it prevents the safety temperature limiter from activating and allows the appliance to continue operating.

[0025] This is also advantageous because ignoring limescale buildup can trigger the safety temperature limiter and result in an unplanned service call. By intervening in the operation of the heating unit, the limescale detection unit can prevent such unplanned service calls. Instead, the appliance can continue to operate at a reduced setpoint temperature until maintenance can be performed. The limescale detection unit can, for example, notify the user of the restricted operation of the heating unit via the control panel.

[0026] The building technology device can be designed as a hot water storage tank, e.g. a wall-mounted storage tank. Reference symbol list 100 household appliances 110 storage containers 111 first upper end 112 second lower end 113 Wall 114 Cold water inlet 115 Hot water outlet 120 heating flange 121 Heating unit 130 pipe 131 Safety temperature limiter 132 Temperature sensor 140 calcification detection unit 150 Control unit 160 temperature sensor 161 Dome sensor QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2004 014 024 A1

[0003] DE 10 2010 002 438 A1

[0004] EP 0 683 633 B1

[0005]

Claims

Domestic appliance (100), comprising a storage container (110) with a first upper end (111), a second lower end (112) and a wall (113), an electric heating unit (120) inside the container (110), a first temperature sensor (160) on the outside of the wall (113), a second temperature sensor (132) in a protective tube (130) in the area of ​​the electric heating unit (120), and a limescale detection unit (140) which is suitable for comparing the temperature readings of the first and second temperature sensors (160, 161, 131, 132) in order to detect a temperature difference and compare it with a target value in order to detect limescale. Domestic technical device (100) according to claim 1, wherein the protective tube (130) is a protective tube for a safety temperature limiter (131), wherein the second temperature sensor (132) is arranged inside the protective tube (130) for the safety temperature limiter (131). Household appliance (100) according to claim 1 or 2, wherein the first temperature sensor (160) is provided as an integral sensor on the wall (113) of the container (110). Domestic appliance (100) according to one of claims 1 to 3, wherein the limescale detection unit (140) is designed to lower a target output temperature for the domestic appliance (100) when limescale is detected in the heating unit (110) in order to avoid switching off the domestic appliance by the safety temperature limiter (131) due to an increased temperature of the electric heating unit (121). Scale detection method for detecting scale buildup in an electric heating unit (121) of a domestic appliance (100), wherein the heating unit (121) is located inside a storage container (110) of the domestic appliance (100), comprising the steps of: detecting a temperature on a wall (113) of the storage container (110) by means of a first temperature sensor (160), detecting a temperature by means of a second temperature sensor (132), which is located inside a protective tube (130) in the area of ​​the electric heating unit (120), and calculating a temperature difference between the temperature values ​​of the second temperature sensor (132) and the temperature measurements of the first temperature sensor (160) and comparing them with a threshold value to detect scale buildup.

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