Laundry care appliance with a control device

Abstract

The present invention relates to a laundry care appliance 100 with a tub 105 for holding washing liquid, wherein the tub 105 has a drain opening 111 and a feed element 113, a pump 117 which is fluidly connected to the drain opening 111 and the feed element 113, a washing liquid feed device 118-1 for supplying washing liquid to the tub 105, a washing drum 107 for holding laundry, wherein the washing drum 107 is arranged in the tub 105, a level sensor 121 which is configured to detect a level of washing liquid in the tub 105, a heating element 123 for heating the washing liquid held in the tub 105 and a control unit 119 which is controllably connected to the washing liquid feed device 118-1, the level sensor 121, the heating element 123 and is connected to pump 117.The control unit 119 is designed, among other things, to activate the heating element 123 during an evaporation period 147 when the detected fill level of washing liquid in the alkaline container 105 is between a minimum and a maximum fill level threshold value 131, 127, and to regulate the heating element 123 in such a way that an increased target temperature is reached in order to evaporate part of the washing liquid during the evaporation period 147 and to create a water vapor atmosphere in the alkaline container 105.

Description

[0001] The present invention relates to a laundry care appliance with a control system.

[0002] In conventional laundry care appliances, the laundry in the washing drum must be heated to ensure a sufficiently high cleaning effect upon contact with the washing liquid. This is achieved in conventional laundry care appliances by introducing a significant amount of washing liquid into the tub, sufficient to move the rotating laundry drum through the washing liquid, thus ensuring contact between the washing liquid and the laundry in the drum. If the washing liquid in the tub is then heated, the heated washing liquid transfers heat to the laundry in the drum. This type of heating of the laundry is also referred to below as "conventional heating" of the laundry.

[0003] This conventional heating of a significant amount of washing liquid, which is usually carried out in conventional laundry care appliances, has the disadvantage that a large amount of water is consumed for each laundry care process and also a large amount of energy is consumed for heating.

[0004] The object underlying the invention is to provide a laundry care appliance which can be operated with reduced water and energy consumption.

[0005] This object is achieved by the subject matter having the features according to the independent claims. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0006] According to a first aspect, the object of the invention is achieved by a laundry care appliance, comprising a tub for holding washing liquid, wherein the tub has a drain opening and a feed element, a pump which is fluidically connected to the drain opening and the feed element, a washing liquid feed device which is designed to feed washing liquid to the tub, a laundry drum for holding laundry, wherein the laundry drum is arranged in the tub, a fill level sensor which is designed to detect a fill level of washing liquid in the tub, a heating element for heating the washing liquid held in the tub, and a controller which is connected for control purposes to the washing liquid feed device, the fill level sensor, the heating element, and the pump, wherein the controller is designedto activate the washing liquid supply device for supplying washing liquid into the tub during a supply period, wherein the control is designed to activate the pump for pumping the supplied washing liquid out of the drain opening and for re-feeding the pumped-out washing liquid through the feed element into the tub during the supply period and / or a wetting period following the supply period, in which in particular the washing liquid supply device is deactivated, in order to circulate the washing liquid and wet the laundry held in the laundry drum with the circulated washing liquid, and wherein the control is designed to activate the heating element during an evaporation period following the supply period or the wetting period,When the washing liquid level in the tub detected by the level sensor lies between a minimum level threshold and a maximum level threshold, the controller is configured to regulate the heating element such that an elevated target temperature is reached, which causes a portion of the washing liquid to evaporate during the evaporation period and a water vapor atmosphere to form in the tub. The elevated target temperature is preferably greater than a washing temperature at which the laundry is to be washed in a subsequent washing period of a laundry care program of the washing machine. The washing temperature can be determined by a temperature set by a customer or by the selected washing program.

[0007] This achieves the technical advantage that the steam atmosphere that forms in the tub effectively heats the laundry in the washing drum using the steam generated.

[0008] This is ensured by ensuring that a sufficient amount of washing liquid is supplied to the tub during the supply period and is circulated by the pump during the supply period and / or the wetting period (also referred to as a pumping process) to effectively wet the laundry in the drum. Part of the circulated washing liquid is retained by the laundry, and the remainder of the washing liquid collects in the lower part of the tub.

[0009] During the evaporation period following the supply period or the wetting period, the controller activates the heating element to heat the remaining washing liquid in the tub to the elevated target temperature and at least partially evaporate it to create the water vapor atmosphere in the tub. For this purpose, the elevated target temperature of the washing liquid is, in particular, at least more than 70°C, in particular more than 80°C.

[0010] In particular, the control system uses a temperature sensor of the laundry care appliance to detect when the temperature of the washing liquid in the tub has reached the increased target temperature.

[0011] Alternatively or additionally, the increased target temperature can be controlled, in particular, via the heating period during which a hysteresis is active.

[0012] Since the laundry is sufficiently moistened during the pumping process, effective heat transfer from the water vapor generated in the tub to the laundry in the washing drum can be achieved without direct contact between the laundry and the washing liquid in the tub.

[0013] During the evaporation period, it is ensured that the heating element is only activated by the control when the level of the washing liquid in the tub is between the minimum level threshold and the maximum level threshold.

[0014] The maximum fill level threshold is below the lowest area of ​​the washing drum to ensure that the washing liquid heated to the increased target temperature does not come into direct contact with the laundry in the washing drum, in order to avoid the burning in of stubborn dirt or to prevent damage to the textiles.

[0015] The minimum fill level threshold is above the heating element, ensuring that the heating element does not run dry and become damaged. The heating element is located in a lower area, specifically the sump, of the laundry appliance's tub.

[0016] Since the filling level of the washing liquid does not exceed the maximum filling level threshold during the evaporation period, a significantly reduced amount of water and also significantly reduced energy for heating the laundry are required compared to conventional laundry care processes, so that the water consumption in the washing process and the overall energy consumption of the laundry care appliance can be significantly reduced.

[0017] During the evaporation period, the laundry is preferably heated to a washing temperature that is lower than the elevated target temperature. For this purpose, the duration of the evaporation period is preferably determined depending on a selected wash program, a selected wash temperature, a selected or detected laundry type, and / or a detected laundry quantity. The specified duration can be determined from experiments and is stored in the control system as a parameter.

[0018] A laundry care appliance is a device used for laundry care, such as a washing machine or a washer-dryer. In particular, such a laundry care appliance is a household laundry care appliance. That is, a laundry care appliance used in household management and used to treat laundry in normal household quantities.

[0019] In an advantageous embodiment, the laundry care appliance has a drum drive for rotating the laundry drum, wherein the control is designed to activate the drum drive for rotating the laundry drum during the feed time period and / or during the wetting time period and / or during the evaporation time period, in particular to rotate the laundry drum alternately in both directions of rotation.

[0020] This achieves the technical advantage that the laundry is moved in the laundry drum by the rotation of the laundry drum, so that complete wetting of the laundry is achieved during the feed time period and / or the wetting time period, or so that complete heating of the laundry is achieved during the evaporation time period.

[0021] In particular, the control is designed to activate the drum drive to rotate the laundry drum at a reduced drum speed during the feed time period and / or during the wetting time period and / or during the evaporation time period, wherein the reduced drum speed is lower than a system speed at which the laundry rests against the laundry drum due to the centrifugal force acting on it in order to prevent the washing liquid from being expelled from the laundry again.

[0022] In an advantageous embodiment, the controller is designed to heat the heating element during the evaporation period to an elevated target temperature of more than 70°C, preferably more than 75°C, more preferably more than 78°C, even more preferably more than 80°C, and most preferably to an elevated target temperature of 82°C.

[0023] This achieves the technical advantage that the corresponding increased target temperatures of the scrubbing liquid are necessary to ensure that a sufficient amount of water vapor is generated.

[0024] In an advantageous embodiment, the laundry care appliance comprises a temperature sensor which is arranged in the tub and is designed to detect a temperature of the washing liquid in the tub, wherein the controller is designed to heat the heating element during the evaporation period during a heating interval until the temperature detected by the temperature sensor corresponds to the target temperature, and wherein the controller is designed to keep the heating element at the target temperature for a predetermined period of time after the target temperature has been reached.

[0025] This achieves the technical advantage that by maintaining the target temperature for a predetermined period of time, it is ensured that a sufficient amount of washing liquid is evaporated to form an effective water vapor atmosphere in the tub.

[0026] In particular, the controller is configured to heat the heating element during the evaporation period during the heating interval until the temperature detected by the temperature sensor is within a target temperature range limited by a minimum target temperature threshold and a maximum target temperature threshold, wherein the controller is configured to keep the heating element in the target temperature range for a predetermined period of time after reaching the target temperature range.

[0027] This provides the technical advantage that a certain deviation or hysteresis can be tolerated within the target temperature range.

[0028] In an advantageous embodiment, the controller is designed to end an active evaporation period, to deactivate a heating element activated during the evaporation period, and to activate the heating element during a heating period if the fill level of washing liquid in the tub detected by the fill level sensor exceeds the maximum fill level threshold before or during the evaporation period, wherein the controller is designed to regulate the heating element during the heating period such that a reduced target temperature is reached which is sufficient to effectively heat the laundry due to direct contact of the washing liquid with the laundry, wherein the reduced target temperature is in particular in a range between 20°C and 65°C, preferably between 40°C and 60°C.The reduced target temperature is lower than the increased target temperature and may also preferably be equal to the washing temperature at which the laundry is to be washed in the following washing time period.

[0029] This achieves the technical advantage that if, after wetting the laundry during the feed period, the fill level of washing liquid in the tub is above the maximum fill level threshold and there is therefore contact between the washing liquid and the laundry in the laundry drum, the heating element is not heated to the increased target temperature in order to avoid damaging the laundry. Instead, in this case, the heating element is heated to a reduced target temperature, so that the washing liquid is only heated to a reduced target temperature, which, however, is sufficient to effectively heat the laundry due to the direct contact between the washing liquid with the high fill level and the laundry. A heating period is understood to be the period in which the washing liquid is heated to the reduced target temperature by the heating element.in which the laundry is heated conventionally.

[0030] In an advantageous embodiment, the controller is designed to activate the washing liquid supply device at least once before or during the evaporation period to supply a further amount of washing liquid into the tub if the filling level of washing liquid in the tub detected by the filling level sensor falls below the minimum filling level threshold value, wherein the controller is designed to activate the heating element during the evaporation period if the filling level of washing liquid in the tub detected by the filling level sensor lies between the minimum filling level threshold value and the maximum filling level threshold value after the at least one supply of the further amount of washing liquid, and wherein the controller is designed to regulate the heating element such that the increased target temperature is reached.

[0031] This achieves the technical advantage that, by adding the additional amount of washing liquid to the tub at least once, sufficient wetting of the laundry can be ensured and effective evaporation compensation for washing liquid evaporated during the evaporation period is achieved. The additional amount of washing liquid can be added several times before or during the evaporation period, in particular twice, three times, or four times.

[0032] In an advantageous embodiment, the controller is designed to activate the washing liquid supply device at least once before or during the heating period to supply a further amount of washing liquid into the tub if the filling level of washing liquid in the tub detected by the filling level sensor falls below the maximum filling level threshold value, and to activate the heating element during the heating period and to regulate the heating element in such a way that the reduced target temperature is reached if the filling level of washing liquid in the tub detected by the filling level sensor exceeds the maximum filling level threshold value after the at least one supply of the further amount of washing liquid, wherein the reduced target temperature is in particular in a range between 20°C and 65°C, preferably between 40°C and 60°C.

[0033] This achieves the technical advantage that sufficient washing liquid is available during the heating period to heat the laundry through direct contact with the washing liquid. For this reason, in this case, the washing liquid is only heated to the reduced target temperature by the control unit using the heating element, or at least an additional amount of washing liquid is added, thus ensuring contact between the washing liquid and the laundry in the washing drum.

[0034] In an advantageous embodiment, the laundry care appliance has a drum drive for rotating the laundry drum. The control system is configured to activate the drum drive to rotate the laundry drum at an expulsion speed, which is in particular between 80 revolutions per minute and 160 revolutions per minute, after the additional amount of washing liquid has been added to the tub at least once and before the heating element is activated, in order to at least partially expel washing liquid from the laundry. In particular, the rotation of the laundry drum at the expulsion speed can also be repeated several times before the heating element is activated.

[0035] This achieves the technical advantage that a portion of the washing liquid bound in the laundry and the excess washing liquid not bound in the laundry can be returned to the tub. This allows the returned washing liquid to provide an additional quantity, in particular a significant portion of the additional washing liquid supplied, for heating with the heating element, and also promotes exceeding the minimum fill level threshold. This also promotes lower water consumption. Furthermore, effective fill level detection by the control system can advantageously be performed after the washing liquid has been expelled.

[0036] In an advantageous embodiment, the controller is configured to activate the washing liquid supply device at least once during a section for heating the washing liquid to supply an additional amount of washing liquid to the tub if the washing liquid level in the tub detected by the level sensor falls below the minimum level threshold. The additional amount of washing liquid can be supplied several times during the section, in particular twice, three times, or four times.

[0037] This provides the technical advantage of achieving effective evaporation compensation and preventing the heating element from running dry each time the washing liquid is heated with the heating element.

[0038] In an advantageous embodiment, the control is designed to deactivate the heating element after the target temperature has been reached, in particular after the predetermined time period, and to end the evaporation period.

[0039] This provides the technical advantage that effective heating of the laundry is achieved after the evaporation period.

[0040] In an advantageous embodiment, the control is designed to activate the pump during a washing period following the evaporation period in order to circulate the washing liquid and to wet the laundry held in the washing drum with the circulated washing liquid.

[0041] This provides the technical advantage of achieving an effective temperature balance between the temperature of the laundry in the washing drum and the washing liquid during the washing period.

[0042] In an advantageous embodiment, the laundry care appliance has a drum drive for rotating the laundry drum, wherein the control is designed to activate the drum drive for rotating the laundry drum during the washing period, in particular at an expulsion speed at which the laundry is applied to the laundry drum due to the centrifugal force acting on it in order to expel washing liquid bound to the laundry.

[0043] This achieves the technical advantage that the washing liquid collected in the tub is cooled by the expulsion before it is subsequently brought into contact with the laundry during the pumping process.

[0044] In an advantageous embodiment, the maximum fill level threshold is below the lowest area of ​​the laundry drum.

[0045] This achieves the technical advantage of avoiding direct contact between the washing liquid heated to the target temperature and the laundry in the washing drum.

[0046] In an advantageous embodiment, the minimum fill level threshold lies above the uppermost area of ​​the heating element.

[0047] This has the technical advantage of preventing the heating element from running dry.

[0048] In an advantageous embodiment, the laundry care appliance has a drum drive for rotating the laundry drum. The control system is configured, after activating the pump during the feed time period and / or the wetting time period and before activating the heating element, to activate the drum drive to rotate the laundry drum at an expulsion speed, which is in particular between 80 revolutions per minute and 160 revolutions per minute, in order to at least partially expel washing liquid from the laundry. In particular, the rotation of the laundry drum at the expulsion speed can also be repeated several times before activating the heating element.

[0049] This achieves the technical advantage of ensuring that there is a sufficient amount of washing liquid in the tub that can be heated before the heating element is activated for the first time.

[0050] Here, the control is particularly designed, after activation of the drum drive, in particular after activation of the drum drive for partially expelling washing liquid from the laundry, to activate the washing liquid supply device at least once to supply a predetermined amount of washing liquid, for example 0.5 liters, into the tub, if the filling level of washing liquid in the tub detected by the filling level sensor after rotation of the laundry drum at the expulsion speed falls below the minimum filling level threshold, wherein the control is designed to activate the heating element if the filling level of washing liquid in the tub detected by the filling level sensor after the at least one supply of the predetermined amount of washing liquid lies between the minimum filling level threshold and the maximum filling level threshold, and wherein the control is designedto regulate the heating element in such a way that an increased target temperature is achieved.

[0051] Thus, by detecting the fill level after activating the drum drive, the saturation of the laundry can be checked, and by adding the predetermined amount of washing liquid, it can be ensured that the laundry is sufficiently saturated and that the fill level of washing liquid in the tub is within the desired range. The predetermined amount of water is preferably determined such that the maximum fill level threshold cannot be exceeded when adding the washing liquid, i.e., the predetermined amount of washing liquid is smaller than the volume between the minimum and maximum fill level threshold resulting from the geometry of the tub. In particular, the predetermined amount of washing liquid is selected from a range of 0.25 to 1 liter.Here, too, the at least one-time supply of the predetermined amount of washing liquid particularly includes the multiple supply of the predetermined amount of washing liquid, in particular the two, three, or four-time supply of the predetermined amount of washing liquid. By supplying the predetermined amount of washing liquid, complete laundry saturation can advantageously be achieved in small steps, thereby avoiding unnecessary supply of washing liquid.

[0052] If the fill level of washing liquid in the tub detected by the fill level sensor continues to be below the minimum fill level threshold after the predetermined amount of washing liquid has been supplied at least once, the controller is designed in particular to deactivate a heating element activated during an evaporation period, to terminate the evaporation heating period and to activate the heating element during a subsequent heating period if the fill level of washing liquid in the tub detected by the fill level sensor is above the maximum fill level threshold after a further supply of washing liquid, and wherein the controller is designed to regulate the heating element in the subsequent heating period such that a reduced target temperature is reached.

[0053] If, even after repeated predetermined additions of washing liquid, it cannot be ensured that the fill level is optimal for washing liquid evaporation, a reduced target temperature is used. An optimal fill level for washing liquid evaporation is reached when the heating element is completely covered with washing liquid and the fill level is below the drum.

[0054] According to a second aspect, the object of the invention is achieved by a method for heating laundry in a laundry care appliance, wherein the laundry care appliance comprises a tub for holding washing liquid, wherein the tub has a drain opening and a feed element, a pump which is fluidically connected to the drain opening and the feed element, a washing liquid feed device which is designed to feed washing liquid to the tub, a laundry drum for holding laundry, wherein the laundry drum is arranged in the tub, a fill level sensor which is designed to detect a fill level of washing liquid in the tub, a heating element for heating the washing liquid held in the tub, and a controller which is control-wise connected to the washing liquid feed device, the fill level sensor, the heating element, and the pump.wherein the method comprises the following method steps: activating the washing liquid supply device by the controller during a supply period for supplying washing liquid into the tub, activating the pump by the controller during the supply period and / or a wetting period following the supply period, during which in particular the washing liquid supply device is deactivated, for pumping the supplied washing liquid out of the drain opening and for re-feeding the pumped-out washing liquid through the supply element to the tub in order to circulate the washing liquid and wet the laundry held in the laundry drum with the circulated washing liquid, and activating the heating element by the controller during an evaporation period following the supply period or the wetting period,If the level of washing liquid in the tub detected by the level sensor is between a minimum level threshold and a maximum level threshold, regulating the heating element by the controller such that an increased target temperature is reached, which causes part of the washing liquid to evaporate during the evaporation period and a water vapor atmosphere to form in the tub.

[0055] This achieves the technical advantage of ensuring that the laundry is heated effectively.

[0056] In particular, the control system checks the saturation of the laundry with washing liquid after the pumping process and before activating the heating element.

[0057] In particular, this results in the washing liquid being expelled by a sufficiently high rotation of the washing drum, thus ensuring that the laundry is sufficiently wetted. This can be achieved, for example, by detecting the fill level by checking whether the fill level is still below the minimum fill level threshold after expulsion, in which case it is assumed that the laundry is not sufficiently wetted, and by checking whether the fill level is above the maximum fill level threshold after this step, in which case it is assumed that the laundry is over-wetted. Secondly, this ensures the ideal fill level without adding large quantities of washing liquid or having to pump out a certain amount of washing liquid.

[0058] The embodiments identified as advantageous embodiments for the laundry care appliance according to the first aspect are also advantageous embodiments for the method according to the second aspect and vice versa.

[0059] Embodiments of the invention are illustrated in the drawings and are described in more detail below.

[0060] They show: Fig. 1 shows a schematic view of a laundry care appliance; Fig. 2 shows a schematic view of a laundry care appliance with a control system according to an embodiment; Fig. 3 shows a schematic view of different fill levels of washing liquid in a tub according to an embodiment; Fig. 4 shows a graphical representation of an evaporation period following a supply period according to an embodiment; Fig. 5 shows a schematic representation of a method for heating laundry in a laundry care appliance; and Fig. 6 shows a further schematic representation of a method for heating laundry in a laundry care appliance.

[0061] Fig. 1 shows a schematic view of a general laundry care appliance 100, such as a washing machine. The laundry care appliance 100 includes a dispenser tray 101 into which laundry care substance, in particular detergent or other liquid substances, can be poured. The laundry care appliance 100 has an appliance housing 102. The laundry care appliance 100 includes an appliance door 103 for loading the laundry care appliance 100 with laundry.

[0062] Fig. 2 shows a schematic view of a laundry care appliance with a control system according to one embodiment. The laundry care appliance 100 has a tub 105 for holding washing liquid, and has a laundry drum 107 for holding laundry. The laundry drum 107 is arranged in the tub 105. The laundry care appliance 100 has a drum drive 109 for rotating the laundry drum 107. The tub 105 has a drain opening 111. The laundry care appliance 100 has a feed element 113. The drain opening 111 is fluidly connected to the feed element 113 by a liquid line 115, wherein a pump 117 for pumping washing liquid through the liquid line 115 is arranged in the liquid line 115.

[0063] The pump 117 can pump washing liquid through the drain opening 111 from the tub 105 during a Fig. 2 pumping process (not shown) into the liquid line 115 and resupply the washing liquid through the liquid line 115 and through the supply element 113 to the tub 105 and the laundry drum 107. This allows the washing liquid to be effectively pumped through the liquid line 115 during a laundry care process or during the execution of a laundry care program and resupplied to the laundry in the laundry drum 107.

[0064] The laundry care appliance 100 has a washing liquid supply device 118-1 for supplying washing liquid into the tub 105, wherein the washing liquid supply device 118-1 is connected to the tub 105 by a supply line 118-2.

[0065] In particular, the washing liquid supply device 118-1 comprises a Fig. 2 not shown dispenser tray 101 of the laundry care appliance 100 and / or a Fig. 2 not shown fresh water connection of the laundry care appliance 100, wherein the controller 119 is designed to activate a washing liquor inlet via the dispenser tray 101 and / or the fresh water connection in order to supply washing liquor and / or fresh water as washing liquid into the laundry drum 107.

[0066] The laundry care appliance 100 further comprises a fill level sensor 121, which is designed to detect a fill level of washing liquid in the tub 105, and further comprises a heating element 123 for heating the washing liquid held in the tub 105.

[0067] The laundry care appliance 100 further comprises a controller 119, which is connected to the pump 117, which is connected to the drum drive 109, to the washing liquid supply device 118-1, the fill level sensor 121 and the heating element 123, each by a control connection 120.

[0068] The laundry care appliance 100 further comprises an outlet line 125, which is fluidically connected to the liquid line 115. The pump 117 is designed to Fig. 2 not shown, to pump washing liquid through the drain opening 111 from the tub 105, through the liquid line 115 and through the outlet line 125 from the laundry care appliance 100, wherein in particular two separate pumps 117 are used, one pump 117 for the pumping process through the outlet line 125 and another pump 117 for the pumping process.

[0069] Fig. 3 shows a schematic view of different filling levels of washing liquid in a tub according to an embodiment.

[0070] In the Fig. 3 a laundry drum 107 arranged in a tub 105 and a heating element 123 arranged in the tub 105 are shown only schematically.

[0071] The present invention aims to ensure a significant reduction in water consumption and energy consumption during a laundry care process by heating the laundry held in the laundry drum 107 not with warm water, but with steam, whereby the amount of water required can be reduced by up to 40% and whereby a significant energy saving effect can also be achieved.

[0072] In order to generate water vapor, the heating element 123 must heat the washing liquid held in the tub 105 to a target temperature, in particular of more than 80°C, so that part of the washing liquid evaporates and a water vapor atmosphere is generated in the tub 105, which can effectively heat the laundry held in the laundry drum 107.

[0073] However, it must be prevented that a washing liquid heated to the increased target temperature comes into direct contact with the laundry, so that the level of the washing liquid during a corresponding heating must always be below the lowest area of ​​the washing drum 107. A correspondingly Fig. 3 The maximum fill level threshold value 127 shown is therefore below the lowest area 129 of the laundry drum 107.

[0074] In addition, the heating element 123 must be prevented from running dry, so that the level of the washing liquid must always be above the heating element 123 during a corresponding heating. A corresponding Fig. 3 The minimum fill level threshold value 131 shown is thus above the heating element 123.

[0075] In order for the heating element 123 to be operated in such a way that an increased target temperature is reached, which causes part of the washing liquid to evaporate during the evaporation period and a water vapor atmosphere to form in the tub 105, the target fill level 133 represented by a dashed line must lie between the minimum fill level threshold value 131 and the maximum fill level threshold value 127.

[0076] In the Fig. 3 Furthermore, an additional fill level threshold 134 is shown, which can also be taken into account by the controller 119, in particular for checking the saturation of the laundry. For example, this additional fill level threshold 134 is below the heating element 123. If the additional fill level threshold 134 is not reached, it can be determined that there is no free washing liquid in the lower area of ​​the tub 105. In particular, if the additional fill level threshold 134 is not reached after a supply of a predetermined amount of water, for example 0.5 liters, and after rotation of the laundry drum 107 with the pump 117 possibly activated to pump the washing liquid around, this indicates that the laundry is not yet fully saturated. If, on the other hand, the additional fill level threshold 134 is exceeded, it can be determined that part of the washing liquid is no longer being absorbed by the laundry, i.e.the laundry is completely saturated.

[0077] Alternatively, the saturation can also be checked in an analogous manner by checking the minimum fill level threshold value 131.

[0078] Fig. 4 shows a graphical representation of an evaporation period following a supply period according to an embodiment.

[0079] Fig. 4 shows a temporal representation of a temperature of the washing liquid in a tub 105 (see the first curve 135 highlighted by circles), a quantity of washing liquid supplied to the tub 105 by a washing liquid supply device 118-1 (see the second curve 137 highlighted by squares) and the fill level of washing liquid in the tub 105 (see the third curve 139 highlighted by triangles), which are plotted along the ordinate axis 141 as a function of time, which is indicated along the abscissa axis 143.

[0080] The Fig. 4 The process shown begins with a feed time period 145 during which the control 119 of the laundry care appliance 100 activates a washing liquid feed device 118-1 for feeding washing liquid into the tub 105, as indicated by the rise of the second curve 137 and as indicated by the rise of the fill level in the tub 105 according to the third curve 139 from the Fig. 4 can be removed.

[0081] During the supply period 145, the controller 119 further activates the pump 117 so that the washing liquid supplied during the supply period 145 is pumped out of the drain opening 111 and the pumped-out washing liquid is fed again to the tub 105 by the feed element 113 in order to circulate the washing liquid and to wet the laundry held in the laundry drum 107 with the circulated washing liquid.

[0082] This can be seen from the drop in the level of the washing liquid following the increase, as shown in the third curve 139 from the Fig. 4 be taken.

[0083] During a wetting period 146 following the supply period 145, during which the washing liquid supply device 118-1 is deactivated, the pump 117 remains activated for pumping. This can be seen from the third curve 139 from the Fig. 4 The supply period 145 and the wetting period 146 can also be understood together as a supply period in which the washing liquid supply device 118-1 is only activated temporarily. In this case, the wetting period can also be omitted.

[0084] During an evaporation period 147 following the wetting period 146 or the supply period 145, the controller 119 activates the heating element 123 if the filling level of washing liquid in the tub 105 detected by the filling level sensor 121 lies between the minimum filling level threshold value 131 and the maximum filling level threshold value 127.

[0085] This can be recognized from the first curve 135 by a significant increase in the temperature of the washing liquid up to a target temperature, in particular to a target temperature of more than 80°C, which causes part of the washing liquid to evaporate during the evaporation period 147 and a water vapor atmosphere to form in the tub 105.

[0086] The steam atmosphere ensures a particularly effective energy transfer to the laundry in the washing drum, and the water and energy consumption of the laundry care appliance 100 can be significantly reduced, while at the same time advantageously moistening the laundry and achieving an advantageous laundry care result.

[0087] In the Fig. 4 In a case not shown, when the filling level of washing liquid in the tub 105 detected by the filling level sensor 121 falls below the minimum filling level threshold value 131, the controller 119 activates the washing liquid supply device 118-1 at least once before and / or during the evaporation period 147 to supply a further amount of washing liquid into the tub 105.

[0088] Subsequently, if necessary after one or more rotations of the laundry drum 107, the controller 119 checks whether the fill level of washing liquid in the tub 105 detected by the fill level sensor 121 lies between the minimum fill level threshold value 131 and the maximum fill level threshold value 127 after the additional amount of washing liquid has been added at least once, whereupon the controller 119 activates the heating element 123 during the evaporation period 147 to heat to the increased target temperature.

[0089] If necessary, the control unit 119 can supply a further amount of washing liquid into the tub 105 several times, in particular up to four times, wherein in this case the drum drive 109 is activated in particular to rotate the laundry drum 107 at different speeds.

[0090] If, after repeated, in particular four times, supply of washing liquid, the minimum fill level threshold 131 is still undershot or the maximum fill level 127 is still exceeded, the controller 119 is designed to deactivate a heating element 123 activated during the evaporation time section 147, to terminate the evaporation heating section 147 and to continue during a subsequent, not in Fig. 4 to activate the heating element 123 during the heating period shown, wherein the controller 119 is designed to regulate the heating element 123 such that a reduced target temperature is reached during the heating period, wherein the reduced target temperature is in particular in a range between 20°C and 65°C, preferably in a range between 40°C and 60°C. It is also possible that at least a further amount of washing liquid is supplied before the activation of the heating element 123, so that direct contact is established between the washing liquid and the laundry in the laundry. Thus, conventional heating of the laundry takes place if, after the washing liquid has been supplied several times, in particular four times, the minimum fill level threshold value 131 is still undershot or the maximum fill level 127 is exceeded.

[0091] The reduced target temperature prevents temperature-related damage to the laundry.

[0092] As in the Fig. 4 As shown, the evaporation period 147 is followed by the washing period 149, during which the pump 117 is activated to circulate the washing liquid and wet the laundry held in the laundry drum 107 with the circulated washing liquid. The level of washing liquid in the tub drops, and the temperature of the washing liquid is also equalized by contact between the laundry and the washing liquid.

[0093] Fig. 5 shows a schematic representation of a method 200 for heating laundry in a laundry care appliance.

[0094] The method 200 comprises, as a first method step, the activation 201 of the washing liquid supply device 118-1 by the controller 119 during a supply time period 145 for supplying washing liquid into the tub 105.

[0095] The method 200 comprises, as a second method step, the activation 203 of the pump 117 by the controller 119 during the supply time period 145 to pump out the supplied washing liquid from the drain opening 111 and to resupply the pumped-out washing liquid through the supply element 113 to the tub 105 in order to circulate the washing liquid and to wet the laundry held in the laundry drum 107 with the circulated washing liquid.

[0096] In particular, the washing liquid is expelled by a sufficiently high rotation of the washing drum 107, thus ensuring that the laundry is sufficiently wetted. This can be achieved, for example, by detecting the fill level by checking whether the fill level after this step is still below the minimum fill level threshold 131, in which case it is assumed that the laundry is not sufficiently wetted, or by checking whether the fill level after this step is above the maximum fill level threshold 129, in which case it is assumed that the laundry is too heavily wetted. On the other hand, the ideal fill level is provided in this way without adding large quantities of washing liquid or having to pump out a certain amount of washing liquid.

[0097] The method 200 comprises, as a third method step, the activation 205 of the heating element 123 by the controller 119 during an evaporation time period 147 following the supply time period 145, when the filling level of washing liquid in the tub 105 detected by the filling level sensor 121 lies between a minimum filling level threshold value 131 and a maximum filling level threshold value 127.

[0098] The method 200 comprises, as a fourth method step, the regulation 207 of the heating element 123 by the controller 119 such that an increased target temperature is reached, which causes a portion of the washing liquid to be evaporated during the evaporation period 147 and a water vapor atmosphere to form in the tub 105.

[0099] The method 200 may include a further step not included in the second method step 203 and the third method step 205. Fig. 5 shown method step for wetting the laundry held in the laundry drum 107 with washing liquid, in which the washing liquid supply device 118-1 is deactivated and in which the pump 117 can be activated for wetting the laundry with the pumped-over washing liquid.

[0100] Fig. 6 shows a further schematic representation of a method 300 for heating laundry in a laundry care appliance.

[0101] The Fig. 6 The method 300 shown includes the Fig. 5 shown process steps 201, 203, 205 and 207. Before the first process step 201, a first process decision is made by querying 301 initial parameters, which can be setting values, such as a treatment temperature, a program setting (cotton / colored, easy-care, wool, etc.) of a selected laundry care program, and / or measured values ​​recorded at the beginning of a laundry care program, such as load quantity, type of laundry. Depending on this initial query 301, the Fig. 5 shown method 200 comprising the method steps 201, 203, 205 and 207 for heating the washing liquid to an increased target temperature or a method for heating the washing liquid to a reduced target temperature (conventional heating of the laundry) comprising a fifth method step 309 for activating the washing liquid supply device 118-1 and a sixth method step 311 and for activating and regulating the heating element 123 to the reduced target temperature.

[0102] In particular, the query 301 of the initial parameters can be used to ensure that the laundry is only heated by evaporating the washing liquid if the laundry or type of laundry to be treated is suitable for this or if there is no particularly large amount of laundry to be treated for which no or only a small saving of water and / or energy is to be expected.

[0103] In method step 309, a fill level of washing liquid is set in the tub 105 or in the laundry drum 107 that is sufficient to allow heating of the laundry through direct contact of the washing liquid with the laundry. Such a fill level is reached, for example, when the fill level in the tub 105 is above the maximum fill level threshold value 127.

[0104] In method 300, after the second method step 203, in particular after washing liquid has been expelled by rotating the laundry drum 107, the fill level is detected using the fill level sensor and compared with the minimum fill level threshold 131 in a second method decision 303. If the detected fill level is less than the fill level threshold 131, the laundry has not yet been fully used, and method steps 201 and 203 are repeated n times, with a predetermined amount being added again upon repeated activation of the washing liquid supply device 118-1, for example, 0.5 liters. A third method decision 305 then queries whether n (number of repetitions) is equal to the maximum number N.If the minimum fill level threshold value 131 is exceeded in the second process decision 303 or the nth repetition of process steps 201 and 203 is reached in the third process decision 305, a fourth process decision 307 checks whether the fill level is between the minimum fill level threshold value 131 and the maximum fill level threshold value 127. If it is determined that the detected fill level is between the minimum fill level threshold value 131 and the maximum fill level threshold value 127, process steps 205 and 207 are carried out to heat the washing liquid to the increased target temperature, or otherwise a conventional heating of the laundry is carried out with process steps 309 and 311 to heat the washing liquid to the reduced target temperature, wherein process step 309 can be omitted if the maximum fill level threshold value 127 has already been exceeded.

[0105] In Fig. 6 It is not shown that a washing time section 149 can follow method step 207 or method step 311.

[0106] All features explained and shown in connection with individual embodiments of the invention can be provided in different combinations in the subject matter according to the invention in order to simultaneously realize their advantageous effects.

[0107] The scope of the present invention is given by the claims and is not limited by the features explained in the description or shown in the figures. Bezugszeichenliste

[0108] 100 Laundry care appliance 101 Dispenser tray 102 Appliance housing 103 Appliance door 105 Tub 107 Laundry drum 109 Drum drive 111 Drain opening 113 Feed element 115 Liquid line 117 Pump 118-1 Washing liquid feed device 118-2 Feed line 119 Controller 120 Control connection 121 Fill level sensor 123 Heating element 125 Outlet line 127 Maximum fill level threshold 129 Bottom area of ​​the laundry drum 131 Minimum fill level threshold 133 Target fill level 134 Additional fill level threshold 135 First curve 137 Second curve 139 Third curve 141 Ordinate axis 143 Abscissa axis 145 Feed time period 146 Wetting time period 147 Evaporation time period 149 Washing time period 200 Method for heating laundry 201 First method step: Activating the washing liquid supply device 203 Second method step: Activating the pump 205 Third method step: Activating the heating element 207 Fourth method step: Regulating the heating element 300 Further method for heatingLaundry 301First process decision: Query the initial parameters 303Second process decision: Detected fill level less than maximum fill level threshold 127? 305Third process decision: Maximum number N reached? 307Fourth process decision: Detected fill level between minimum fill level threshold 131 and maximum fill level threshold 127 309Fifth process step: Activation of the washing liquid supply device 311Sixth process step: Activation and control of the heating element

Claims

1. Laundry care appliance (100) with a tub (105) for holding washing liquid, wherein the tub (105) has a drain opening (111) and a feed element (113), a pump (117) which is fluidically connected to the drain opening (111) and the feed element (113), a washing liquid feed device (118-1) which is designed to feed washing liquid to the tub (105), a laundry drum (107) for holding laundry, wherein the laundry drum (107) is arranged in the tub (105), a fill level sensor (121) which is designed to detect a fill level of washing liquid in the tub (105), a heating element (123) for heating the washing liquid held in the tub (105) and a controller (119) which is control-technically connected to the washing liquid feed device (118-1), the level sensor (121), the heating element (123) and the pump (117), characterized in thatthe controller (119) is designed to activate the washing liquid supply device (118-1) for supplying washing liquid into the tub (105) during a supply time period (145), that the controller (119) is designed to activate the pump (117) for pumping the supplied washing liquid out of the drain opening (111) and for feeding the pumped-out washing liquid back into the tub (105) through the supply element (113) during the supply time period (145) and / or a wetting time period (146) following the supply time period (145), in which in particular the washing liquid supply device (118-1) is deactivated, in order to circulate the washing liquid and to wet the laundry held in the laundry drum (107) with the circulated washing liquid, and that the controller (119) is designed,to activate the heating element (123) during an evaporation period (147) following the supply period (145) or the wetting period (146) if the fill level of washing liquid in the tub (105) detected by the fill level sensor (121) lies between a minimum fill level threshold value (131) and a maximum fill level threshold value (127), wherein the controller (119) is designed to regulate the heating element (123) such that an increased target temperature is reached, which causes part of the washing liquid to evaporate during the evaporation period (147) and a water vapor atmosphere to form in the tub (105).

2. Laundry care appliance (100) according to claim 1, characterized in thatthe laundry care appliance (100) has a drum drive (109) for rotating the laundry drum (107), wherein the controller (119) is designed to activate the drum drive (109) for rotating the laundry drum (107) during the feed time period (145) and / or during the wetting time period (147) and / or during the evaporation time period (147), in particular to rotate the laundry drum (107) alternately in both directions of rotation.

3. Laundry care appliance (100) according to claim 1 or 2, characterized in that the controller (119) is configured to heat the heating element (123) during the evaporation period (147) to an elevated target temperature of more than 70°C, preferably more than 75°C, more preferably more than 78°C, even more preferably more than 80°C, and most preferably to an elevated target temperature of 82°C.

4. Laundry care appliance (100) according to one of the preceding claims, characterized in thatthe laundry care appliance (100) has a temperature sensor which is arranged in the tub (105) and is designed to detect a temperature of the washing liquid in the tub (105), wherein the controller (119) is designed to heat the heating element (123) during the evaporation period (147) during a heating interval until the temperature detected by the temperature sensor corresponds to the target temperature, and wherein the controller (119) is designed to keep the heating element (123) at the target temperature for a predetermined period of time after the target temperature has been reached.

5. Laundry care appliance (100) according to one of the preceding claims, characterized in thatthe controller (119) is designed to end an active evaporation period (147), to deactivate a heating element (123) activated during the evaporation period (147), and to activate the heating element (123) during a heating period if the fill level of washing liquid in the tub (105) detected by the fill level sensor (121) exceeds the maximum fill level threshold value (127) before or during the evaporation period (147), wherein the controller (119) is designed to regulate the heating element (123) during the heating period such that a reduced target temperature is reached which is sufficient to effectively heat the laundry due to direct contact of the washing liquid with the laundry, wherein the reduced target temperature is in particular in a range between 20°C and 65°C, preferably between 40°C and 60°C.

6. Laundry care appliance (100) according to one of the preceding claims, characterized in that the controller (119) is designed to activate the washing liquid supply device (118-1) at least once before or during the evaporation period (147) to supply a further amount of washing liquid into the tub (105) if the filling level of washing liquid in the tub (105) detected by the filling level sensor (121) falls below the minimum filling level threshold value (131), wherein the controller (119) is designed to activate the heating element (123) during the evaporation period (147) if the filling level of washing liquid in the tub (105) detected by the filling level sensor (121) lies between the minimum filling level threshold value (131) and the maximum filling level threshold value (127) after the at least one supply of the further amount of washing liquid, and wherein the controller (119) is designed to regulate the heating element (123) such that the increased Target temperature is reached.

7. Laundry care appliance (100) according to claim 5, characterized in thatthe controller (119) is designed to activate the washing liquid supply device (118-1) at least once before or during the heating period to supply a further amount of washing liquid into the tub (105) if the filling level of washing liquid in the tub (105) detected by the filling level sensor (121) falls below the maximum filling level threshold value (131), wherein the controller (119) is designed to activate the heating element (123) during the heating period if the filling level of washing liquid in the tub (105) detected by the filling level sensor (121) exceeds the maximum filling level threshold value (127) after the at least one supply of the further amount of washing liquid, and wherein the controller (119) is designed to regulate the heating element (123) such that the reduced target temperature is reached, wherein the reduced target temperature is in particular in a range between 20°C and 65°C,preferably between 40°C and 60°C.

8. Laundry care appliance (100) according to claim 6 or 7, characterized in that the laundry care appliance (100) has a drum drive (109) for rotating the laundry drum (107), wherein the control (119) is designed, after the at least one supply of the further amount of washing liquid into the tub (105) and before the activation of the heating element (123), to activate the drum drive (109) for rotating the laundry drum (107) at an expulsion speed which is in particular between 80 revolutions per minute and 160 revolutions per minute, in order to expel washing liquid at least partially from the laundry.

9. Laundry care appliance (100) according to one of the preceding claims, characterized in thatthe controller (119) is designed to activate the washing liquid supply device at least once during a section for heating the washing liquid to supply a further amount of washing liquid into the tub (105) if the filling level of washing liquid in the tub (105) detected by the filling level sensor (121) falls below the minimum filling level threshold value (131).

10. Laundry care appliance (100) according to one of the preceding claims, characterized in that the controller (119) is designed to deactivate the heating element (123) after reaching the target temperature, in particular after the predetermined time period, and to end the evaporation period (147).

11. Laundry care appliance (100) according to one of the preceding claims, characterized in thatthe control (119) is designed to activate the pump (117) during a washing time period (149) following the evaporation time period (147) in order to pump the washing liquid around and to wet the laundry held in the laundry drum (107) with the pumped-around washing liquid.

12. Laundry care appliance (100) according to claim 11, characterized in that the laundry care appliance (100) has a drum drive (109) for rotating the laundry drum (107), wherein the controller (119) is designed to activate the drum drive (109) for rotating the laundry drum (107) during the washing time section (149), in particular at an expulsion speed in order to expel washing liquid bound to the laundry.

13. Laundry care appliance (100) according to one of the preceding claims, characterized in that the maximum fill level threshold (127) is below the lowest area (129) of the laundry drum (107).

14. Laundry care appliance (100) according to one of the preceding claims, characterized in that the minimum fill level threshold (131) is above the uppermost area of ​​the heating element (123).

15. A method (200) for heating laundry in a laundry care appliance (100), wherein the laundry care appliance (100) comprises a tub (105) for receiving washing liquid, wherein the tub (105) has a drain opening (111) and a feed element (113), a pump (117) which is fluidically connected to the drain opening (111) and the feed element (113), a washing liquid feed device (118-1) which is designed to supply washing liquid to the tub (105), a laundry drum (107) for receiving laundry, wherein the laundry drum (107) is arranged in the tub (105), a fill level sensor (121) which is designed to detect a fill level of washing liquid in the tub (105), a heating element (123) for heating the washing liquid received in the tub (105), and a Control (119) which is control-technically connected to the washing liquid supply device (118-1), the level sensor (121),the heating element (123) and the pump (117), characterized in thatthe method (200) comprises the following method steps: activating (201) the washing liquid supply device (118-1) by the controller (119) during a supply time period (145) for supplying washing liquid into the tub (105), activating (203) the pump (117) by the controller (119) during the supply time period (145) and / or a wetting time period (146) following the supply time period (145), in which in particular the washing liquid supply device (118-1) is deactivated, for pumping the supplied washing liquid out of the drain opening (111) and for feeding the pumped-out washing liquid again through the supply element (113) to the tub (105) in order to circulate the washing liquid and to wet the laundry held in the laundry drum (107) with the circulated washing liquid,and activating (205) the heating element (123) by the controller (119) during an evaporation period (147) following the supply period (145) or the wetting period (146) when the fill level of washing liquid in the tub (105) detected by the fill level sensor (121) lies between a minimum fill level threshold value (131) and a maximum fill level threshold value (127), regulating (207) the heating element (123) by the controller (119) such that an increased target temperature is reached, which causes a portion of the washing liquid to evaporate during the evaporation period (147) and a water vapor atmosphere to form in the tub (105).

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