CN112127120A

CN112127120A - Laundry care appliance with a pump device and method for operating a laundry care appliance

Info

Publication number: CN112127120A
Application number: CN202010580622.1A
Authority: CN
Inventors: K·哈恩; R·勒默尔; S·韦策尔
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2019-06-25
Filing date: 2020-06-23
Publication date: 2020-12-25
Anticipated expiration: 2040-06-23
Also published as: EP3757273B1; DE102019209149A1; CN112127120B; PL3757273T3; EP3757273A1

Abstract

The invention relates to an operating method and a laundry care appliance having a lye container with a discharge opening and an inlet element, a pump device, a discharge line connecting the discharge opening to the pump device, a pump-out line connecting the pump device to an area outside the laundry care appliance, a circulating pump line connecting the pump device to the inlet element. The pump device has a first pump for pumping washing liquid out of the lye container via the pump-out line and out of the laundry care appliance, and the pump device has a second pump for re-feeding washing liquid out of the lye container via the circulating pump-out line and via the inlet element. During a first period of time, a pump is activated to pump the washing liquid to the liquid level in the pump-out line or in the circulation pump line. During a second period of time, a further pump is activated, which pumps the washing liquid from the pump-out line or the circulation pump line to a liquid level in the respective other line.

Description

Laundry care appliance with a pump device and method for operating a laundry care appliance

Technical Field

The invention relates to a laundry care appliance having a pump device and to a method for operating such a laundry care appliance.

Background

In conventional laundry care appliances, laundry care substances (e.g. different detergents or softeners) are applied by the user to the wash-in housing of the laundry care appliance. Water is supplied to the rinsing housing via a water connection of the laundry care appliance, wherein the laundry care substance is rinsed out of the rinsing housing by the supplied water and is supplied to the lye container. The laundry care substance, which is present in most cases as a powder, then forms a solution with the amount of water flushed in the lye container. This dissolution process is mainly carried out in a diffusive manner (difusionstartig) and therefore requires a certain period of time. This period of time can be shortened by: the water which is introduced is set in motion in the lye container, for example by the rotation of the drum, so that the dissolution process additionally also takes place in a convective manner (konvektionsarig). In the case of an improper overdosing of the laundry care substance by the user, the laundry care substance dissolving process can be prolonged or the powdered laundry care substance is not completely dissolved. Undissolved laundry care substances in the lye container can in some cases damage the laundry to be treated in high concentrations and can lead to discoloration of the laundry, in particular when the detergent residues come into contact with the laundry.

GB 2099462 a discloses a washing machine in which excessive consumption of laundry care substances is to be avoided. The washing machine is configured to: during the washing process, the pump is switched on briefly and at intervals in order to feed the washing liquid with the laundry care substance into the pump-out hose, wherein the washing liquid alternately rises and sinks in the pump-out hose, whereby the laundry care substance is to be dissolved.

In the circulation pumping system in conventional laundry care appliances, the washing liquid is pumped out of the lye container by means of a second pump (in particular a circulation pump) and is resupplied to the laundry via the circulation pumping line and via the inlet element.

In conventional circulation pumping systems in laundry care appliances, the lye container overflow closure mechanism is usually dispensed with

This is because there is no fear of detergent loss due to the presence of the circulation pumping system, and in the case of detergent loss, the detergent concentration in the washing liquid becomes small. Undissolved, usually still powdery detergent, which, as a result of gravity, has left the lye container through its opening without taking part in the washing process, can be immediately resupplied to the lye container and thus to the laundry as a result of the activation of the circulation pump, wherein the detergent should here already be present in dissolved form, in particular to the greatest extent, in order to prevent fading damage to the laundry. With the circulation pump system in conventional laundry care appliances, after the laundry care process has ended, the spent washing liquid is pumped out of the laundry care appliance by means of a first pump (in particular a pump-out pump) via a pump-out line.

In WO 2017/039549 a1 a method for dissolving detergent in a washing machine with a circulation pumping system is disclosed. In the method, during the washing process, the pump is switched on and off at short intervals in order to convey the washing liquid with the washing agent into the circulating pumping hose, wherein the pump is stopped before the washing liquid reaches the highest point in the circulating pumping hose.

In the methods according to GB 2099462 a and WO 2017/039549 a1, it is disadvantageous that after the pump (or circulation pump) has been switched off, the washing liquid flows back uncontrollably, as a result of which it may happen that washing liquid with detergent that has not yet dissolved may flow back into the laundry drum. This cannot reliably prevent: contact of highly concentrated detergent with the laundry and local laundry fading.

Disclosure of Invention

The object of the present invention is, in particular, to provide a laundry care appliance and a method for operating such a laundry care appliance, in which the advantageous dissolution of the laundry care substance in the washing liquor is improved (in particular ensured). In addition, the laundry care appliance and the operating method according to the invention enable an improved self-cleaning effect of the pump device and the liquid conducting path connected thereto.

This object is achieved by the subject matter having the features according to the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the description and the drawings, wherein advantageous embodiments of the laundry care appliance can simultaneously realize advantageous embodiments of the method for operating the laundry care appliance and vice versa.

According to a first aspect, the object is achieved according to the invention by a laundry care appliance having: a lye container for receiving washing liquor, wherein the lye container has a discharge opening and an inlet element (in particular an inlet nozzle); a pump device for pumping a washing liquid; a discharge line connecting the discharge opening to the pump device in terms of fluid technology; a pump-out line which fluidically connects the pump device to an outer region of the laundry care appliance; a circulating pumping line fluidically connecting the pump device to the inlet element, wherein the pump device has a first pump which is designed to: the washing liquid is pumped out of the laundry care appliance (in particular with a calibrated pumping power) from the lye container via the discharge opening, via the discharge line and via the pump-out line, wherein the pump device has a second pump which is configured for: pumping washing liquid (in particular with a calibrated pumping power) from the lye container via the discharge opening and via the discharge line into the circulation pumping line, and resupplying washing liquid from the circulation pumping line and via the inlet element to the lye container, and the laundry care appliance having a control device for controlling the pump device, wherein the control device is configured for: activating one of the pumps of the pump device for pumping washing liquid during a first time period (in particular with a reduced pumping power) in order to pump washing liquid to the liquid level in the pump-out line or to the liquid level in the circulating pump line, and wherein the control device is configured for: in a second time period following the first time period (in particular with a reduced pumping power), another of the pumps of the pump device for pumping the washing liquid is activated in order to pump the washing liquid from the respective pump-out line or circulation pump line and to pump the pumped washing liquid to a liquid level in the respective other line (i.e. circulation pump line or pump-out line) of the pump-out line or circulation pump line.

This achieves the technical advantage that: a more effective and faster dissolution of the laundry care substances in the washing liquor can be ensured, since the laundry care substances are not only dissolved by the slower diffusion process, but also the process can be superimposed by additional convection. In this case, it is particularly advantageous if, by means of the conveying (or reversing) of the washing liquid between the pump-out line and the circulation pump line, a higher flow velocity can be generated by a smaller line cross section of the pump-out line (or circulation pump line) relative to the discharge line, and thus the convection effect can be increased. Furthermore, wetting of the laundry by means of the not yet completely dissolved detergent is avoided, since this counteracts a backflow of the washing liquid into the lye container. Furthermore, by means of the resulting flow of washing liquid, contaminants or blockages which may accumulate in the lines and/or the pump are dissolved, whereby a self-cleaning effect on the line course can be achieved.

Preferably, the control device is configured in particular to: activating a delivery mode of operation of a first pump with reduced pumping power for a first period of time

In order to pump (or lift) the washing liquid to a liquid level (flssigkeitspegel) in the pump-out line, and the control device is configured in particular for: the second pump is activated with a reduced pumping power for a second time period following the first time period in order to pump washing liquid from the pump-out line and to pump (or lift) the pumped washing liquid to a liquid level in the circulation pump line. In this connection, it is possible to use,the first pump is switched off, in particular, in response to the activation of the second pump.

Alternatively, the control device is in particular designed to: the second pump is activated in a delivery mode of operation with a reduced pumping power for a first period of time in order to pump the washing liquid to a liquid level in the circulation pumping line, and the control device is configured in particular to: the method further comprises activating a delivery operating mode of the first pump with a reduced pumping power during a second time period following the first time period in order to pump the washing liquid from the circulation pumping line and to pump the pumped washing liquid to a liquid level in the pump-out line without forming a delivery flow when the liquid level is reached. In this case, the second pump is switched off, in particular, in response to activation of the first pump.

In particular, by activating the additional pump for a second time period following the first time period, such a technical advantage is achieved: by pumping (or lifting) the washing liquid by the respective pump for a first period of time and by subsequently (in particular actively) conducting the pumped washing liquid back there by the further pump, an effective dissolution of undissolved residues of the laundry care substance in the washing liquid is achieved. The advantageous dissolution of the laundry care substance is ensured by the strong convection of the washing liquid with the laundry care substance, which occurs when the washing liquid actively flows through the pump device, wherein the strong convection is caused in particular by the high flow speed of the washing liquid on the respective pump impeller of the respective pump.

The dissolution process of the laundry care substances in the washing liquor is thereby improved by a multiple of this convection and is therefore achieved more rapidly than in the case of the convection-type dissolution processes known from the prior art or in the case of dissolution processes which proceed diffusely.

In conventional laundry care appliances, the laundry care substance is pre-dosed into the rinsing housing by the user. Water is flushed into the flushing-in housing via a water connection of the laundry care appliance, and a mixture of laundry care substance and water is flushed as washing liquid from the feed line into the lye container. In most cases, the still powdered detergent is deposited at the bottom in the lye container and is dissolved diffusely and conditionally very slowly with the washing liquor. In general, the dissolution process of the powdery laundry care substances is improved slightly in a convective manner by the rotation of the washing drum.

In particular, because of the excessive improper dosing by the user, the laundry care substance present in the washing liquor cannot be completely dissolved, so that undissolved residues of the laundry care substance (for example, powdered detergent) may remain in the washing liquor. Undissolved residues of laundry care substances can cause discoloring damage at high concentrations on the laundry to be treated and should therefore be avoided.

A circulation pumping system and a method for detergent dissolution are known from WO 2017/039549 a1, but such fading damage cannot be reliably avoided with such laundry care appliances.

In the laundry care appliance according to the invention, the respective pump pumps the washing liquid into the pump-out line or into the circulation pump line for a first period of time until the pumped washing liquid reaches a liquid level in the respective line, so that the flow of the supply fluid is interrupted and only one liquid column on the pressure side is formed. By performing a delivery interruption (or delivery reduction) or a liquid column exclusively built up on the pressure side after the first period of time, it is possible to prevent: the pumped washing liquid is either supplied from the circulation pumping line to the laundry via the inlet element or pumped out of the laundry care appliance via the pump-out line during the first period of time. In this case, the first or second pump of the circulation pumping system is operated, in particular, with a reduced impeller speed, so that the liquid column on the pressure side is lifted, and a continuous conveying flow is not established here.

After the end of the first time period, in a second time period, another of the pumps is activated, wherein washing liquid is pumped from the respective pump-out line or circulation pump line and the pumped washing liquid is pumped to the liquid level in the respective other line of the pump-out line or circulation pump line (i.e. the circulation pump line or pump-out line). In this case, a reduced impeller speed can again be used for the pump drive, so that a transport flow is built up in a short time, which occurs as soon as a water column of the desired liquid level has been formed in the respective other pressure line on the pressure side.

The pumps therefore pump the washing liquid back and forth between the pressure-side pump-out line (first water drain) and the pressure-side circulation pump line (further water drain) during the first and second time periods, as a result of which a favorable dissolution of the laundry care substance in the washing liquid is achieved as a result of corresponding convection currents (which are achieved by the flow velocity in the pressure-side water drain), as a result of which the washing liquid can be supplied to the laundry in the laundry drum during the subsequent circulation pumping without damage or discoloration to the laundry being caused by undissolved residues of the laundry care substance. In particular, this method is characterized in that after the first pump has been switched off, a further pump is activated in a targeted manner in order to convey the washing liquid which has returned as a result of the switching off of the first pump from one discharge element in the pressure-side discharge system to the other discharge element on the pressure side in a controlled manner. This has the advantage, in addition to the high flow velocity in the drainage parts, which is determined by the cross section: the washing liquid can be prevented from flowing back into the lye container uncontrollably.

In order to prevent the washing liquid from being pumped out of the laundry care appliance, the liquid level in the pump-out line is located in particular below the outlet opening. If the pump-out line has a section, which is determined by the user-specific installation conditions, which extends above the outlet opening (i.e. at a geodetically higher potential), the liquid level is in particular located below the section of the pump-out line which extends above the outlet opening. Furthermore, the pump-out line can be designed such that it is divided into a line section on the pump side and a line section on the outlet side, wherein the line section on the pump side and the line section on the outlet side are connected to one another in the upper region of the laundry care appliance. This embodiment is also known as "waterscape" (Wasserberg). In this embodiment, the pumping-out of the washing liquid is prevented if it is ensured that the liquid level in the pump-side line section of the pump-out line lies in particular below the upper point of the pump-out line (in particular the connection point between the pump-side line section and the line section on the discharge side). This embodiment has the advantage that: the discharge opening can also be located below the liquid level.

In order to prevent the washing liquid from being resupplied to the laundry via the inlet element (in particular the spray nozzle) before the detergent has completely dissolved, the second liquid level in the circulation pumping line is in particular located below the inlet element. If the circulation pumping line has a section which extends above the inlet element (i.e. at a geodetically higher potential), the liquid level is in particular located below the section of the circulation pumping line which extends above the inlet element.

In view of this increased level of liquid in the previously described section, the detergent dissolution described here can be optimized, since, on the one hand, increased flow velocities occur, which promote convection for the detergent dissolution. On the other hand, the delivery must be longer in time, as a result of which an increased liquid level is formed in the pressure lines of the hydraulic circuit system and the hydraulic evacuation system, so that the relationship between the pumping time and the holding time at the vibration reversal point is improved in the case of maximum vibration amplitudes at the reached liquid level. Eventually, the pumping time is extended while the holding time at the reversing point remains the same, so that this proportion in time becomes larger.

In order to ensure that the washing liquid pumped by the respective pump during the first (or second) time period does not exceed the respective liquid level in the circulation pumping line or the pump-out line and thus is not supplied to the laundry (or is not pumped out of the laundry care appliance) via the inlet element, the respective pump can be activated only briefly, wherein the activation duration (or operating duration) is less than the nominal (nominal) operating duration of the respective pump for circulating the washing liquid (or pumping out) in the case of normal (or nominal) operation. The activation duration may be predetermined for the first (or another) time period depending on the pumping power of the respective pump. Alternatively, the activation duration can also be determined as a function of the measured pumping power, or the respective pump can be deactivated upon confirmation of the attainment of the respective liquid level within the first (or second) time period. The normal operating conditions of the pump are understood to mean the states: in this state, the washing liquid conveyed by the pump is returned to the lye container during the circulating pumping or is conveyed out of the laundry care appliance during the pumping out.

Furthermore, in order to ensure that the washing liquid pumped by the respective pump reaches the respective liquid level in the circulating pumping line or the pump-out line after the first (or second) period of time, the above-mentioned reduced pumping power of the respective pump can be in particular greater than the counter-flow of the washing liquid in the pump-out line or the circulating pumping line caused by gravity.

In order to ensure that the washing liquid pumped by the respective pump during the first (or second) time period does not exceed the respective liquid level in the circulation pumping line or the pump-out line and is therefore not supplied to the laundry (or is not pumped out of the laundry care appliance) via the inlet element, the above-mentioned reduced pumping power of the respective pump is in particular less than the nominal pumping power of the respective pump for circulating (or pumping out) the washing liquid in the case of normal (or nominal) operation.

In particular, the above-mentioned reduced pumping power of the respective pump is sufficient, whereby the pumping pressure exerted on the washing liquid by the respective pump and the oppositely directed counter-flow on the washing liquid caused by gravity are in equilibrium at the respective liquid level, so that the liquid column in the respective pressure line can briefly remain at the respective desired maximum liquid level.

In particular, the control device is configured to: when the washing liquid has reached the liquid level in the circulation pump line or the pump-out line, the first time period is ended and the other of the pumps is activated for a second time period, and/or the control device is configured in particular for: the second time period ends when the pumped-out washing liquid has reached the liquid level in the respective other line of the circulation pump line or the pump-out line, i.e. the pump-out line or the circulation pump line.

The detergent dissolution is carried out over time until all the washing material is completely dissolved in the liquid phase of the washing liquid. In order to evaluate the detergent dissolution time, in particular, the torque-generating drive current or the phase bypass current (phasestrangstrom) of the three-phase synchronous pump drive can additionally be evaluated. In the temporally high-resolution current profile, it can be recognized that: whether the medium is present in two or one phase. If the fluid is present in two phases (i.e. the powdered detergent and the washing liquid have not yet formed a solution), the mixture will exhibit a different time-torque profile during the transport than if the fluid was present in a single phase, since the solid phase (in particular the powdered detergent) is already dissolved in the washing liquid when the fluid is present in a single phase. The width of the fluctuation around the time average for the torque is less pronounced for single-phase fluids than for two-phase mixtures. This behavior can also be highlighted if the density difference between the solid and liquid phases is also more pronounced and therefore also significantly represented in the temporally high-resolution torque profile.

A laundry care appliance is understood to be an appliance (for example a washing machine or a washer dryer) which is used for laundry care. Such a laundry care appliance is understood to be, in particular, a household laundry care appliance. Namely, such a laundry care appliance: the laundry care appliance is used in the household sector and treats household-used amounts of laundry with the aid of the laundry care appliance.

Furthermore, washing liquor is understood to be such a liquid medium which is supplied to a laundry care appliance for treating laundry: the liquid medium is supplied with laundry care substances (detergents, detergent ingredients, softeners, enhancers, etc.) or already contains laundry care substances. Such a liquid medium is preferably water or an aqueous solution. Washing liquid is understood in particular not only as washing liquid which is supplied during a washing process time period, but also as liquid which is supplied during other time periods of a laundry care process (for example soaking time periods or rinsing time periods).

In an advantageous embodiment of the laundry care appliance, the pump device has a common suction chamber which is fluidically connected (in particular via a suction line) to the discharge line, the pump device has a circulating pumping pressure chamber which is fluidically connected (in particular via a circulating pumping pressure line) to the circulating pumping line, and the pump device has a pump-out pressure chamber which is fluidically connected (in particular via a pump-out pressure line) to the pump-out line, wherein the circulating pumping pressure chamber is fluidically connected via a circulating pumping suction line to the common suction chamber, wherein the pump-out pressure chamber is fluidically connected via a pump-out suction line to the common suction chamber, wherein the first pump comprises a pump-out pressure chamber, and wherein, the second pump includes a cyclical pumping pressure chamber.

This achieves the technical advantage that: it is ensured that a first pump (in particular an evacuation pump) of the pump device can suck in washing liquid from the common suction chamber via the pump-out suction tube and pump it into the pump-out line via the pump-out pressure chamber, and that a second pump of the pump device can suck in washing liquid from the common suction chamber via the circulation pump-out suction tube and pump it into the circulation pump line via the circulation pump-out pressure chamber. If the first pump is first actuated with the above-described reduced pumping power during the corresponding time period, the first pump sucks in the rinsing liquid from the discharge line, from the common suction chamber, from the pump-out suction line and also from the deactivated pressure line, and pumps the sucked-in rinsing liquid from the pump-out pressure chamber up to the liquid level in the pump-out line.

If the second pump (in particular the circulation pump) is then operated with the above-described reduced pumping capacity during the respective time period, the second pump sucks in the washing liquid only from the pump-out line on the pressure side and sucks in it via the common suction chamber via the circulation pumping suction line and pumps the sucked-in washing liquid via the circulation pumping suction line via the circulation pumping pressure chamber up to the liquid level in the circulation pumping line.

The first and second pumps of the pump device may each have a pump drive. Alternatively, the first and second pumps can be realized with only one pump drive, wherein, for example, a circulatory pumping can be realized by the first pump by rotation of the pump drive in a first rotational direction and a pumping can be realized by the second pump by rotation of the pump drive in the opposite rotational direction. Such a pump device with two pumps and only one pump drive can advantageously have a common suction chamber with a suction connection and a common pressure chamber, wherein the common pressure chamber can have a pump-out pressure connection and a circulating pump-up pressure connection, which are arranged such that the feed of washing liquid via the one or the other pressure connection is dependent on the direction of rotation of the common pump drive. Alternatively, the selection can be made as a function of the direction of rotation by providing blocking devices on the pressure side in the circuit pump feed line and the pump-out feed line. Such a pump arrangement with a single pump drive for the first and second pumps can be realized particularly cost-effectively. Thus, according to the invention, a first pump and a second pump are understood as being such pumps, respectively: the pump is provided for pumping out (or for circulating pumping) the washing liquid, wherein the first pump and the second pump may be physically provided in one or both pump devices.

In an advantageous embodiment of the laundry care appliance, the control device is configured to: after the end of the second time period, the first time period and a second time period following the first time period are repeated in order to pump washing liquid alternately back and forth by the pumps of the pump device between a liquid level in the pump-out line and a liquid level in the circulating pump line, wherein the control device is configured in particular for: the first and second time periods are repeated periodically in order to pump washing liquid back and forth by the pumps of the pump device in a periodic manner alternately between a liquid level in the pump-out line and a liquid level in the circulating pump line.

This achieves the technical advantage that: the wash liquid may be conveyed back and forth between the conduits by the pumps a plurality of times by one or more repetitions of the first and second time periods. The dissolution efficiency of the undissolved laundry care substance can be improved in that not only the diffusion process, but also the diffusion process is superimposed on the convection process during the dissolution of the laundry care substance, and the dissolution rate can thus be increased by a multiple.

During the reciprocating pumping, the washing liquid does not reach the suction region of the pump device, since the exchange of washing liquid only takes place between the pressure side of the first pump, the pump-out pressure chamber, the pump-out suction line, the common suction chamber, the circulation pump-out suction line, the circulation pump-out pressure chamber, and the pressure side of the second pump, and therefore the washing liquid no longer flows back into the suction line connection of the suction chamber and also into the discharge line.

In an advantageous embodiment of the laundry care appliance, the control device is configured to: after the end of the first or second time period, a subsequent second or first time period is started directly in order to pump washing liquid from the respective pump-out line or circulation pump line by the pump of the pump device in a non-intermittent manner and to pump the pumped-out washing liquid into the respective other line (i.e. circulation pump line or pump-out line) of the pump-out line or circulation pump line, or the control device is configured to: during the time period between the first and second time periods and/or during the time period between the second and first time periods, the pump activated during the previous time period continues to be operated in order to keep the washing liquid at the respective liquid level in the pump-out line or the circulation pump line during this time period.

This achieves the technical advantage that: if there is no time section between these periods, the washing liquid can be pumped back and forth between the pump-out line and the circulation pump line in a manner that is not intermittent. In contrast thereto, if the washing liquid is held at the respective liquid level during the time sections between the above-mentioned time periods, for example: too quickly, the washing liquid flows back and forth and air may be sucked in connection therewith.

In an advantageous embodiment of the laundry care appliance, the control device is configured to: the pumps which are activated during the first and/or second time periods, respectively, are activated in a periodically staggered manner with reference to the natural period of the washing liquid column which oscillates at the natural frequency between the pump-out line and the circulation pump line.

This achieves the technical advantage that: by activating the respective pumps in a periodically staggered manner, a wobbling of the oscillating water column (Aufschaukeln) caused by resonance effects can be avoided.

In an advantageous embodiment of the laundry care appliance, the washing liquid column oscillates between the pump-out line and the circulation pump line during a first and a second time period at a natural frequency ω, which is given by the following equation: omega ═ 2g/h)^1/2Wherein g is the gravitational acceleration on the earth, and wherein h is the height of the respective liquid level in the pump-out line or the circulation pump line relative to the zero point of the washing liquid in the respective circulation pump line or pump-out line, wherein the control device is configured for: the pumps are alternately activated during the first and second time periods at an activation frequency that is different from the natural frequency of the vibrating wash liquor.

This achieves the technical advantage that: the rocking of the water column caused by resonance is avoided.

In an advantageous embodiment of the laundry care appliance, the control device is configured to: directly (in particular with a high speed gradient) increasing the pumping power of the respective pump to the reduced pumping power at the beginning of the respective time period, in order to deliver the washing liquid with the reduced pumping power without a delay at the beginning of the respective time period, or the control device is designed to: the pumping power of the respective pump is continuously increased (in particular with a small rotational speed gradient) to the above-mentioned reduced pumping power during the pumping period (Pumpzeitraum) at the beginning of the respective time period.

This achieves the technical advantage that: depending on the specific requirements, the pumping power of the pump can be increased to the above-mentioned reduced pumping power immediately and without delay, or the pumping power can be increased continuously. In particular, a high revolution gradient comprises a value of 30001/min/s. In particular, a small revolution gradient includes a value of 2501/min/s.

In an advantageous embodiment of the laundry care appliance, the laundry care appliance has a power detection element for detecting an electrical power characteristic of the respective pump, wherein the control device is designed to: comparing the detected electrical power characteristic with a reference power characteristic of the respective pump, wherein the control device is configured to: the corresponding time period is ended based on the comparison of the detected electric power characteristic with the reference power characteristic.

This achieves the technical advantage that: the reference power characteristic corresponds here to such a power characteristic of the respective pump: in the case of the power characteristic, the respective pump pumps the washing liquid to the respective liquid level in the pump-out line or the circulation pump line. If the detected electrical power characteristic in particular corresponds to the reference power characteristic or lies within a tolerance range of the reference power characteristic, the control device can recognize: the washing liquid has reached the respective liquid level and the control device can end the respective time period. It is assumed here that: if the two-phase medium is still pumped out first and the medium is present completely in a single phase after the detergent dissolution process, the power requirement changes significantly. Even though the power requirements may vary only slightly during the detergent dissolution process, high frequency fluctuations in the motor power may occur due to the presence of the first solid phase in the liquid phase.

In an advantageous embodiment of the laundry care appliance, the laundry care appliance has a power detection element for detecting a further electrical power characteristic of the respective pump, wherein the control device is designed to: comparing the detected further electrical power characteristic with a further reference power characteristic of the respective pump, wherein the control device is configured to: based on the comparison of the detected further electrical power characteristic with the further reference power characteristic, a second pump for pumping washing liquid is activated with a calibrated pumping power during a third time period following the second time period, in order to re-feed washing liquid to the lye container via the circulating pumping line and via the inlet element.

This achieves the technical advantage that: when the laundry care substance is advantageously (in particular completely) dissolved in the washing liquor, this can be detected by comparing the detected further electrical power characteristic of the lye pump with the further reference power characteristic. This is the case when the further reference power characteristic corresponds to the detected further electrical power characteristic.

In an advantageous embodiment of the laundry care appliance, the power detection element comprises a current sensor for detecting the supply current and/or the torque-generating current of the respective pump.

In an advantageous embodiment of the laundry care appliance, the laundry care appliance has a level sensor for detecting a level of washing liquid in the circulation pump line, wherein the control device is designed to: if the detected washing liquid level corresponds to the liquid level in the circulation pump line, the corresponding time period is ended, and/or the laundry care appliance has a further level sensor for detecting a further washing liquid level in the pump-out line, wherein the control device is designed to: the respective time period is ended when the detected washing liquid level corresponds to a further liquid level in the pump-out line.

This achieves the technical advantage that: the end of the respective time period can advantageously be indicated to the control device by means of at least one level sensor.

According to a second aspect of the invention, the object is achieved by a method for operating a laundry care appliance, wherein the laundry care appliance has a lye container for receiving washing liquor, wherein the lye container has a discharge opening and an inlet element, wherein the laundry care appliance has: a pump device for pumping washing liquid, a discharge line connecting the discharge opening fluidically to the pump device, a pump-out line connecting the pump device fluidically to an outer region of the laundry care appliance, a circulation pump line connecting the pump device fluidically to the inlet element, and a control device for controlling the pump device, wherein the pump device has a first pump which is designed to: the washing liquid is pumped out of the lye container (in particular with a calibrated pumping capacity) via the discharge opening, via the discharge line and via the pump-out line from the laundry care appliance, wherein the pump device has a second pump which is designed to: the washing liquid is pumped (in particular with a calibrated pumping capacity) from the lye container via the discharge opening and via the discharge line into the circulating pumping line, and the washing liquid is resupplied from the circulating pumping line and via the inlet element to the lye container, wherein the method has the following method steps: one of the pumps of the pump device for pumping washing liquid is activated by the control device (in particular with reduced pumping power) during a first time period in order to pump washing liquid to the liquid level in the pump-out line or to the liquid level in the circulation pump line, and another of the pumps of the pump device for pumping washing liquid is activated by the control device (in particular with reduced pumping power) during a second time period following the first time period in order to pump the pumped-out washing liquid to the liquid level in the respective other line (i.e. circulation pump line or pump-out line) of the pump-out line or circulation pump line.

This achieves the technical advantage that: a more effective and faster dissolution of the laundry care substances in the washing liquor can be ensured, since the laundry care substances are not only dissolved by the slower diffusion process, but also the process can be superimposed by additional convection.

In an advantageous embodiment of the method, the method has the further method steps: during a first time period following the second time period, one of the pumps of the pump device for pumping washing liquid is reactivated by the control device with a reduced pumping capacity in order to pump washing liquid from the respectively corresponding other line of the pump-out line or the circulation pump line (i.e. the circulation pump line or the pump-out line) and to re-pump the pumped washing liquid to the liquid level in the pump-out line or to the liquid level in the circulation pump line; and in a second time period following the first time period, another of the pumps of the pump device for pumping washing liquid is reactivated by the control device with a reduced pumping power in order to pump the pumped washing liquid to a liquid level in the respective other line of the pump-out line or the circulation pump line (i.e. the circulation pump line or the pump-out line).

In an advantageous embodiment of the method, the method comprises: the liquid level in the pump-out line and the liquid level in the circulating pump line are alternately (in particular periodically) pumped back and forth, wherein such periodic alternating pumping back and forth comprises in particular a sinusoidal oscillation.

In an advantageous embodiment of the method, the activation of the respective pumps is carried out by the control device in a periodically staggered manner with reference to the natural period of the washing liquid column oscillating at the natural frequency between the pump-out line and the circulating pump line.

Drawings

Further embodiments are explained with reference to the attached drawings. The drawing shows that:

fig. 1 shows a schematic view of a laundry care appliance;

fig. 2 shows a schematic view of a laundry care appliance with a pump device;

FIG. 3 shows a diagrammatic illustration of the pumping process of the pump device in a laundry care appliance; and

fig. 4 shows a schematic representation of a method for dissolving laundry care substances in a laundry care appliance.

Detailed Description

Fig. 1 shows a schematic view of a generic laundry care appliance 100, such as for example a washing machine. The laundry care appliance 100 comprises a rinsing housing 101, into which rinsing housing 101 a laundry care substance, such as, for example, a detergent, can be injected. The laundry care appliance 100 comprises a door 103 for loading the laundry care appliance 100 with laundry.

Fig. 2 shows a schematic view of a laundry care appliance with a pump device.

The laundry care appliance 100 has a lye container 105 for receiving washing liquor. The laundry care appliance 100 has a laundry drum 107 for receiving laundry. The lye container 105 has a discharge opening 109 for the discharge of washing liquid from the lye container 105. The laundry care appliance 100 has an inlet element 111 (in particular an inlet nozzle), which inlet element 111 is configured for: the circulated pumped washing liquid is fed to the lye container 105 (or to the laundry received in the laundry drum 107).

The laundry care appliance 100 has a discharge line 113, which discharge line 113 fluidically connects the discharge opening 109 to a pump device 115 for pumping washing liquid. The laundry care appliance 100 furthermore has a pump-out line 117, which pump-out line 117 fluidically connects the pump device 115 to an outer region 119 of the laundry care appliance 100, which is only schematically illustrated in fig. 2. The outlet opening 121 of the laundry care appliance 100 is shown here schematically. The laundry care appliance 100 furthermore has a circulation pumping line 123, which circulation pumping line 123 fluidically connects the pump device 115 to the inlet element 111.

The pump apparatus 115 has a first pump 125-1, the first pump 125-1 configured to: washing liquid is pumped out of the laundry care appliance 100 from the lye container 105 via the discharge opening 109, via the discharge line 113 and via the pump-out line 117 with a calibrated pumping power in order to remove spent washing liquid from the laundry care appliance 100 temporally after the washing process.

The pump apparatus 115 has a second pump 125-2, the second pump 125-2 being configured to: the washing liquid is pumped with a calibrated pumping capacity from the lye container 105 via the discharge opening 109 via the discharge line 113 into the circulation pumping line 123, and the pumped washing liquid is resupplied from the circulation pumping line 123 via the inlet element 111 to the lye container 105 in order to re-wet the laundry with the washing liquid within the framework of the circulation pumping process or to re-saturate the already wetted laundry for improving the cleaning process (or the washing process).

As shown in fig. 2, the pump devices 115 have a common suction chamber 127, the suction chamber 127 being fluidically connected (in particular via a suction connection) to the discharge line 113, the pump devices 115 have a circulating pumping pressure chamber 129, the circulating pumping pressure chamber 129 being fluidically connected (in particular via a circulating pumping pressure connection) to the circulating pumping line 123, and the pump devices 115 have a pump-out pressure chamber 131, the pump-out pressure chamber 131 being fluidically connected (in particular via a pump-out pressure connection) to the pump-out line 117. Here, the first pump 125-1 comprises a pump-out pressure chamber 131 and a pump-out suction line, not shown in particular in fig. 2, and the second pump 125-2 comprises a circulating pump-out pressure chamber 129 and a circulating pump-out suction line, not shown in particular in fig. 2.

The laundry care appliance 100 furthermore has a control device 133 for controlling the pump device 115, which control device 133 is configured to: the first pump 125-1 or the second pump 125-2 of the pump device 115 for pumping the washing liquid is activated.

During a laundry care process, the user supplies a laundry care substance, for example a detergent, into a rinsing housing 101, not shown in fig. 2, of the laundry care appliance 100. Water is introduced into the rinsing-in housing 101 via the household water connection of the laundry care appliance 100 by means of a solenoid valve, wherein the laundry care substance is supplied together with the water via a feed line, not shown in fig. 2, to the lye container 105 and accumulates in the lower region of the lye container 105 in the vicinity of the discharge opening 109.

During the washing process, the laundry drum 107 is moved and the dissolution of the laundry care substance is promoted mainly by diffusion processes and convection processes (due to the drum rotation), whereby a homogeneous washing liquid is obtained in a relatively time-consuming manner. Since undissolved highly concentrated laundry care substances on the laundry can cause fading damage, a rapid and complete dissolution of the laundry care substance is necessary, for example, in order not to damage the laundry during the washing process if the user improperly feeds the laundry care substance into the flush-in housing 101 (e.g., overdosing).

In conventional laundry care appliances 100 without a circulation pumping system, a lye container seal is usually arranged on the discharge opening 109, which prevents an unintentional outflow of washing liquor from the lye container 105 via the discharge opening 109, as a result of which, without a circulation pumping system, the laundry care substance can be lost and the washing process carried out can no longer have the expected washing result.

In the circulation pumping system shown in fig. 2, the lye container seals are usually dispensed with and the loss of laundry care substance is compensated for by the washing-technical process design (for example by additional components) in order to ensure favorable washing results. For this purpose, the detergent dissolved in the washing liquid is always supplied again to the laundry by the circulation function by activating the circulation pump.

The control device 133 is designed to: one of the pumps 125-1,125-2 of the pump means 115 for pumping washing liquid is activated with a reduced pumping power during a first period of time in order to pump washing liquid to the liquid level 135-1 in the pump-out line 117 or to the liquid level 135-2 in the circulation pump line 123.

The control device 133 is designed to: the other one of the pumps 125- < 1 > < 125 > < 2 > of the pump means 115 for pumping washing liquid is activated with a reduced pumping power during a second time period following the first time period in order to pump washing liquid from the respective pump-out line 117 or circulation pump line 123 and to pump the pumped washing liquid to the liquid level 135- < 1 > < 135 > < 2 > in the respective other one of the pump-out line 117 or circulation pump line 123, i.e. the circulation pump line 123 or the pump-out line 117.

Thus, the washing liquid located in the discharge line 113 is pumped back and forth between the circulation pump line 123 and the pump-out line 117 by the temporal activation of the two pumps 125-1,125-2 of the pump device 115, so that the process of diffusive dissolution of the laundry care substance is accelerated considerably by corresponding convection. The washing liquid pumped back and forth here flows through the pressure chambers 129,131 of the pump device 115 and the common suction chamber 127, in particular between the circulation pump line 123 and the pump-out line 117, while the washing liquid pumped back and forth here cannot enter the lye container 105 via the discharge opening 109, so that contact of undissolved laundry care substances with the laundry in the laundry drum 107 can be prevented during the dissolving process.

Here, however, unlike the pump-out process (or the cyclical pumping process), the respective pumps 125-: the washing liquid pumped by the first pump 125-1 is pumped only to the liquid level 135-1 in the pump-out line 117, without being pumped beyond the liquid level 135-1 out of the laundry care appliance 100 via the outlet opening 121, and the washing liquid pumped by the second pump 125-2 is pumped only to the liquid level 135-2 in the circulation pump line 123, without being fed beyond the liquid level 135-2 to the laundry in the laundry drum 107 via the inlet element 111.

In one embodiment, control device 133 is configured to: the first pump 125-1 of the pump device 115 for pumping washing liquid is activated with a reduced pumping power for a first period of time in order to pump washing liquid to the liquid level 135-1 in the pump-out line 117, and the control device 133 is configured for: the second pump 125-2 of the pump device 115 for pumping washing liquid is activated with a reduced pumping power for a second time period following the first time period in order to pump washing liquid from the pump-out line 117 and to pump the pumped washing liquid to the liquid level 135-2 in the circulating pump line 123.

In a further embodiment, the control device 133 is designed to: activating the second pump 125-2 of the pump device 115 for pumping washing liquid with a reduced pumping power for a first period of time in order to pump washing liquid to the liquid level 135-2 in the circulating pumping line 123, and the control device 133 is configured for: the first pump 125-1 of the pump device 115 for pumping washing liquid is activated with a reduced pumping power for a second time period following the first time period in order to pump washing liquid from the circulation pumping line 123 and to pump the pumped washing liquid to the liquid level 135-1 in the pumping-out line 117.

In order to prevent the washing liquid from being pumped out of the outlet opening 121, the liquid level 135-1 in the pump-out line 117 is located in particular below the outlet opening 121. If the pump-out line 117 has a section extending above the outlet opening 121, the liquid level 135-1 is located in particular below the section of the pump-out line 117 extending above the outlet opening 121.

In order to prevent the washing liquid from being resupplied to the laundry via the inlet element 111, a liquid level 135-2 in the circulation pumping line 123 is located in particular below the inlet element 111. If the circulation pumping line 123 has a section extending above the inlet element 111, the liquid level 135-2 is in particular located below the section of the circulation pumping line 123 extending above the inlet element 111.

In order to ensure a particularly advantageous dissolution process of the laundry care substance, the control device 133 is designed to: after the end of the second time interval, the first time interval and the second time interval following the first time interval are repeated, wherein the control device 133 is designed in particular to: the first and second time periods are periodically repeated in time.

The control device 133 thus alternately activates the first and second pumps 125 and 125-2 of the pump device 115 in order to pump washing liquid back and forth, in particular periodically back and forth, between the liquid level 135-1 in the pump-out line 117 and the liquid level 135-2 in the circulation pump line 123, whereby a favorable dissolution of the laundry care substance can be ensured.

The control device 133 is designed in particular to: the subsequent second or first period starts directly after the end of the first or second period, so that the washing liquid is not pumped intermittently by the pumps 125-.

Alternatively, the control device 133 is configured in particular for: during the time segment between the first and second time segments, and/or during the time segment between the second and first time segments, the pump 125-. Undesired resonance of the oscillating washing liquid column between the pump-out line 117 and the circulating pump line 123 can be counteracted by the respectively corresponding further pump 125-.

In particular, the control device 133 is designed to: the pumps 125-.

In particular, the column of washing liquid oscillates between the pump-out line 117 and the circulation pump line 123 during the first and second periods of time with a natural frequency ω, which is given by the following equation: omega ═ 2g/h)^1/2, wherein g is the gravitational acceleration on earth, and wherein h is the height of the respective liquid level 135-: these pumps 125-1,125-2 are activated alternately during the first and second time periods at an activation frequency which is different from the natural frequency of the washing liquid in which the vibration occurs.

The control device 133 is designed to: the pumping power of the respective pump 125-.

Alternatively, the control device 133 is configured to: the pumping power of the respective pump 125-. In particular, the reduced pumping power is greater than the counter-flow of the washing liquid in the pump-out line 117 or the circulation pump line 123 caused by gravity, since the flow in a system with vibration capability is frictional.

The laundry care appliance 100 has, in particular, a power detection element 137 for detecting the electrical power characteristic of the respective pump 125-: comparing the detected electrical power characteristic with a reference power characteristic of the respective pump 125-: the corresponding time period is ended based on the comparison of the detected electric power characteristic with the reference power characteristic. The power characteristic may comprise, for example, a supply current and/or a motor torque of the respective pump motor.

Here, the reference power characteristic corresponds to such power characteristic of the respective pump 125- "1, 125-2: in the case of the power characteristic, the respective pump 125-. If the detected electrical power characteristic is particularly identical to the reference power characteristic or within a tolerance range of the reference power characteristic, the control device 133 can recognize: the washing liquid has reached the respective liquid level 135-.

The power detection element 137 is furthermore especially configured for detecting further electrical power characteristics of the respective pump 125-. Here, the control device 133 is configured to: the detected further electrical power characteristic is compared with a further reference power characteristic of the respective pump 125-. The control device 133 is designed in particular to: based on the comparison of the detected further electric power characteristic with the further reference power characteristic, the second pump 125-2 for pumping washing liquid is activated with a calibrated pumping power during a third time period following the second time period in order to pump washing liquid via the discharge opening 109 and via the discharge line 113 into the circulation pumping line 123 and to re-feed washing liquid pumped into the circulation pumping line 123 to the lye container 105 through the inlet element 111.

Here, the power detection element 137 has identified a power threshold value of: at this power threshold, the initially undissolved two-phase washing liquor, which comprises the solid, powdery washing additive and the liquid fluid, ends up completely monophasically and can be fed to the washing batch without problems, without the risk of the laundry fading.

Since there is a high temporal resolution in the detection of the motor torque (i.e. in the detection of the current forming the torque), it can be detected by means of a further power characteristic by the power detection element 137: whether there is still undissolved residue of the laundry care substance (for example powdery residue of detergent) in the washing liquid pumped by the pump device 115. When the laundry care substance has been completely dissolved in the washing liquid, the control means 133 can be identified by a comparison of the detected further electrical power characteristic of the respective pump 125-.

If the detected further electrical power characteristic corresponds to the further reference power characteristic, the control device 133 may operate the second pump 125-2 at the calibrated pumping power for a subsequent third time period after the end of the second time period and ensure an efficient supply of washing liquid into the lye container 105 via the inlet element 111 within the framework of the circulating pumping process.

In one embodiment, the laundry care appliance 100 has, in particular, a fill level sensor for detecting the fill level of the washing liquid in the circulation pump line 123, wherein the control device 133 is designed to: if the detected washing liquid level corresponds to the liquid level 135-2 in the circulation pump line 123, the corresponding time period is ended, and/or the laundry care appliance 100 has, in particular, a further level sensor for detecting a further washing liquid level in the pump-out line 117, wherein the control device 133 is designed to: the corresponding time period is ended when the detected washing liquid level corresponds to the liquid level 135-1 in the pump-out line 117.

By alternately pumping (or transporting back) the washing liquid by the pump device 115 during the first (or second) time period, an advantageous dissolution of the laundry care substance in the washing liquid is achieved. In this way, damage to the laundry by undissolved laundry care substance can be avoided in the event of an incorrect dosing of the laundry care substance.

Fig. 3 shows a diagrammatic representation of the pumping process of the pump device in the laundry care appliance.

The diagram (a) of fig. 3 shows the pumping power of the second pump 125-2, in particular the circulation pump, of the pump arrangement 115 along the ordinate axis 139, wherein the pumping power is shown on the basis of time, which is given along the abscissa axis 141. Diagram (b) of fig. 3 shows the pumping power of the first pump 125-1 (in particular the pump-out pump) of the pump device 115 along the ordinate axis 139, wherein the pumping power is shown on the basis of time, which is given along the abscissa axis 141.

Diagram (c) of fig. 3 shows along the ordinate axis 139 the height of the washing liquid column in the circulation pumping line 123 fluidically connected to the second pump 125-2, wherein this height is shown on the basis of time, which is indicated along the abscissa axis 141. Diagram (c) of fig. 3 shows along a further ordinate axis 140 the height of the washing liquid column in the pump-out line 117 fluidically connected to the first pump 125-1, wherein this height is shown on the basis of time, which is shown along the abscissa axis 141.

During a first time period 143-1, the second pump 125-2 is activated by the control device 133 of the laundry care appliance 100 and the washing liquid is pumped into the circulation pumping line 123 with a reduced pumping power 145-1 until the level of washing liquid in the circulation pumping line 123 reaches a liquid level 135-2 in the circulation pumping line 123.

During a second time period 143-2 following the first time period 141, the second pump 125-2 is deactivated and the first pump 125-1 is activated and washing liquid is pumped into the pump-out pump 117 with a reduced pumping power 145-1 until the level of washing liquid in the pump-out line 117 reaches the liquid level 135-1 in the pump-out line 117.

The first time segment 143-1 is again followed after the second time segment 143-2 and the second time segment 143-2 is again followed after this new first time segment 143-1, wherein the control device 133 repeats these time segments 143 and 143-2, in particular for so long as the laundry care substance is completely dissolved or until these time segments 143 and 143-2 are stopped after a certain number of repetitions.

As a first method step, the method 200 comprises: one of the pumps 125-1,125-2 of the pump device 115 for pumping scrubbing liquid is activated 201 by the control means 133 with a reduced pumping power 145-1 during a first time period 143-1 in order to pump scrubbing liquid to the liquid level 135-1 in the pump-out line 117 or to the liquid level 135-2 in the circulation pump line 123.

As a second method step, the method 200 comprises: the other one of the pumps 125- < 1 > < 125 > -2 of the pump means 115 for pumping scrubbing liquid is activated 203 by the control device 133 with a reduced pumping power 145-1 during a second time period 143-2 following the first time period 143-1 in order to pump the pumped scrubbing liquid to the liquid level 135- < 1 > < 135 > < 2 > in the respective other one of the pump-out line 117 or the circulation pump line 123, i.e. the circulation pump line 123 or the pump-out line 117.

All features explained and illustrated in connection with a single embodiment of the invention can be provided in different combinations in the subject-matter according to the invention in order to achieve their advantageous effects at the same time.

The scope of protection of the invention is derived from the claims and is not limited by the features explained in the description or shown in the drawings.

List of reference numerals

100 washing nursing device

101 punch-in shell

103 door

105 lye container

107 washing drum

109 discharge opening

111 inlet element

113 discharge line

115 pump apparatus

117 pump-out line

119 outer region

121 discharge opening

123 circulation pumping pipeline

125-1 first pump

125-2 second pump

127 common suction chamber

129 cycle pumping pressure chamber

131 pump out pressure chamber

133 control device

135-1 level of liquid in the pump-out line

135-2 level of liquid in the circulating pumping line

137 power detecting element

139 ordinate axis

140 further axis of ordinates

141 axis of abscissa

143-1 first time period

143-2 second time period

145-1 reduced pumping power

200 method for dissolving laundry care substances

201 first method step: activating one of these pumps

203 second method step: activating another of the pumps

Claims

1. A laundry care appliance (100) having:

-a lye container (105) for receiving washing liquor,

wherein the lye container (105) has a discharge opening (109) and an inlet element (111),

-a pump device (115) for pumping a washing liquid,

a discharge line (113) which fluidically connects the discharge opening (109) to the pump device (115),

a pump-out line (117) which fluidically connects the pump device (115) to an outer region (119) of the laundry care appliance (100),

wherein the pump device (115) has a first pump (125-1) configured for: pumping washing liquid out of the lye container (105) from the laundry care appliance (100) via the discharge opening (109), via the discharge line (113) and via the pump-out line (117), and

-control means (133) for controlling the pump device (115),

wherein the control device (133) is configured to: activating a first pump (125-1) of the pump device (115) for pumping washing liquid up to a liquid level (135-1) in the pump-out line (117),

it is characterized in that the preparation method is characterized in that,

the laundry care appliance (100) is configured with a circulation pumping line (123) which fluidically connects the pump device (115) to the inlet element (111),

wherein the pump device (115) has a second pump (125-2) configured for: pumping washing liquid from the lye container (105) via the discharge opening (109) and via the discharge line (113) into the circulating pumping line (123) and re-feeding the washing liquid from the circulating pumping line (123) and via the inlet element (111) to the lye container (105),

the control device (133) is designed to: activating one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for a first period of time (143-1) for pumping washing liquid in order to pump washing liquid up to the liquid level (135-1) in the pump-out line (117) or up to the liquid level (135-2) in the circulation pump line (123), and

the control device (133) is designed to: activating, in a second time period (143-2) following the first time period (143-1), another one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for pumping washing liquid from the respective pump-out line (117) or circulation pump line (123) and pumping the pumped washing liquid up to a liquid level (135-1, 135-2) in the respective other pump-out line (117) or circulation pump line (123).

2. Laundry care appliance (100) according to claim 1,

it is characterized in that the preparation method is characterized in that,

the first pump (125-1) is configured to: pumping washing liquid from the lye container (105) out of the laundry care appliance (100) via the pump-out line (117) with a calibrated pumping capacity,

the second pump (125-2) is configured to: re-feeding washing liquid from the lye container (105) via the inlet element (111) to the lye container (105) with a calibrated pumping power,

the control device (133) is designed to: activating one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) with a reduced pumping power (145-1) for the first period of time (143-1) for pumping washing liquid, and

the control device (133) is designed to: activating another one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) with a reduced pumping power (145-1) for the second period of time (143-2) for pumping washing liquid.

3. Laundry care appliance (100) according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the pump device (115) has a common suction chamber (127) which is connected to the discharge line (113) in terms of fluid technology, in particular by means of a suction connection,

the pump device (115) has a circulating pumping pressure chamber (129) which is connected to the circulating pumping line (123) in terms of fluid technology, in particular by means of a circulating pumping pressure line connection, and

the pump device (115) has a pump-out pressure chamber (131) which is connected to the pump-out line (117) in terms of fluid technology, in particular by means of a pump-out pressure pipe connection,

wherein the circulating pumping pressure chamber (129) is fluidically connected to the common pumping chamber (127) by a circulating pumping line,

wherein the pump-out pressure chamber (131) is fluidically connected to the common suction chamber (127) by means of a pump-out suction line,

wherein the first pump (125-1) comprises the pump-out pressure chamber (131), and

wherein the second pump (125-2) comprises the cyclical pumping pressure chamber (129).

4. The laundry care appliance (100) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the control device (133) is designed to: repeating the first time period (143-1) and a second time period (143-2) following the first time period (143-1) after the end of the second time period (143-2) in order to alternately pump washing liquid back and forth between the liquid level (135-1) in the pump-out line (117) and the liquid level (135-2) in the circulating pump line (123) by the above-mentioned pumps (125-1, 125-2) of the pump device (115),

wherein the control device (133) is configured in particular to: -periodically repeating the first and second time periods (143-1, 143-2) for periodically alternately pumping back and forth washing liquid through the above-mentioned pump (125-1, 125-2) of the pump device (115) between the liquid level (135-1) in the pump-out line (117) and the liquid level (135-2) in the circulating pump line (123).

5. The laundry care appliance (100) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the control device (133) is designed to: starting a subsequent second or first time period (143-2, 143-1) directly after the end of the first or second time period (143-1, 143-2) in order to pump washing liquid from the respective pump-out line (117) or circulation pump line (123) by means of the above-mentioned pump (125-1, 125-2) of the pump device (115) in a non-intermittent manner and to pump the pumped washing liquid into the respective other line of the pump-out line (117) or circulation pump line (123), or

The control device (133) is designed to: during the time section between the first time period and the second time period (143-1, 143-2) and/or during the time section between the second time period and the first time period (143-2, 143-1), the pump (125-1, 125-2) activated during the previous time period (143-1, 143-2) continues to be operated in order to keep the washing liquid at the respective liquid level (135-1, 135-2) in the pump-out line (117) or the circulation pump line (123) during this time section.

6. The laundry care appliance (100) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the column of washing liquid oscillates between the pump-out line (117) and the circulation pump line (123) during the first and second periods of time (143-1, 143-2) at a natural frequency ω, which is given by the following equation: omega ═ 2g/h)^1/2，

Wherein g is the acceleration of gravity on the earth, and

wherein h is the height of the respective liquid level (135-1, 135-2) in the pump-out line (117) or the circulation pump line (123), relative to the zero point of the washing liquid in the respective circulation pump line (123) or pump-out line (117),

wherein the control device (133) is configured to: -activating the above-mentioned pump (125-1, 125-2) during the first and second periods of time (143-1, 143-2) alternately at an activation frequency which is different from the natural frequency of the washing liquid in which the vibration occurs.

7. The laundry care appliance (100) according to any of claims 2 to 6,

it is characterized in that the preparation method is characterized in that,

the control device (133) is designed to: increasing the pumping power of the respective pump (125-1, 125-2) to the reduced pumping power (145-1) directly at the beginning of the respective time period (143-1, 143-2), in particular with a high speed gradient, in order to deliver the washing liquid at the reduced pumping power (145-1) without a delay at the beginning of the respective time period (143-1, 143-2), or

The control device (133) is designed to: the pumping power of the respective pump (125-1, 125-2) is increased to the reduced pumping power (145-1) continuously, in particular with a small rotational speed gradient, during the pumping period at the beginning of the respective time period (143-1, 143-2).

8. The laundry care appliance (100) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the laundry care appliance (100) has a power detection element (137) for detecting an electrical power characteristic of the respective pump (125-1, 125-2),

wherein the control device (133) is configured to: comparing the detected electrical power characteristic with a reference power characteristic of the respective pump (125-1, 125-2),

wherein the control device (133) is configured to: ending the respective time period (143-1, 143-2) based on a comparison of the detected electrical power characteristic with the reference power characteristic.

9. The laundry care appliance (100) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the laundry care appliance (100) having a power detection element (137) for detecting a further electrical power characteristic of the respective pump (125-1, 125-2),

wherein the control device (133) is configured to: comparing the detected further electrical power characteristic with a further reference power characteristic of the respective pump (125-1, 125-2),

wherein the control device (133) is configured to: based on the comparison of the detected further electrical power characteristic with the further reference power characteristic, the second pump (125-2) is activated with a calibrated pumping power during a third time period following the second time period (143-2) for pumping washing liquid for re-feeding washing liquid to the lye container (105) via the circulating pumping line (123) and via the inlet element (111).

10. Laundry care appliance (100) according to claim 8 or 9,

it is characterized in that the preparation method is characterized in that,

the power detection element (137) comprises a current sensor for detecting the supply current and/or the torque-forming current of the respective pump (125-1, 125-2).

11. The laundry care appliance (100) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the laundry care appliance (100) has a fill level sensor for detecting a fill level of washing liquid in the circulation pump line (123), wherein the control device (133) is designed to: ending the respective time period (143-1, 143-2) and/or when the detected level of washing liquid corresponds to a level of liquid (135-2) in the circulation pumping line (123)

The laundry care appliance (100) has a further fill level sensor for detecting a further fill level of washing liquid in the pump-out line (117), wherein the control device (133) is designed to: the respective time period (143-1, 143-2) is ended when the detected washing liquid level corresponds to a further liquid level (135-1) in the pump-out line (117).

12. A method (200) for operating a laundry care appliance (100),

wherein the laundry care appliance (100) has a lye container (105) for receiving washing liquor,

wherein the laundry care appliance (100) has:

-a pump device (115) for pumping a washing liquid,

-control means (133) for controlling the pump device (115),

wherein the method (200) comprises the steps of:

-activating (201) a first pump (125-1) of the pump device (115) for pumping washing liquid in order to pump washing liquid up to a liquid level (135-1) in the pump-out line (117),

it is characterized in that the preparation method is characterized in that,

wherein the laundry care appliance (100) has a circulation pumping line (123) which fluidically connects the pump device (115) to the inlet element (111), and

the method (200) comprises the following method steps:

-activating (201), by means of the control device (133), one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for pumping washing liquid for a first period of time (143-1), for pumping washing liquid up to the liquid level (135-1) in the pump-out line (117) or up to the liquid level (135-2) in the circulation pump line (123), and

-activating (203), by means of the control device (133), another one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for pumping washing liquid in a second time period (143-2) following the first time period (143-1), in order to pump the pumped washing liquid up to a liquid level (135-1, 135-2) in the respective other one of the pump-out line (117) or the circulation pump line (123).

13. The method (200) of claim 12,

it is characterized in that the preparation method is characterized in that,

the second pump (125-2) is configured to: re-feeding washing liquid from the lye container (105) to the lye container (105) via the inlet element (111) with a calibrated pumping power, and

the method (200) has the further method steps of:

-activating (201) one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for pumping washing liquid with a reduced pumping power (145-1) by the control means (133) during the first time period (143-1), and

-activating (203), by means of the control device (133), in a second time period (143-2) following the first time period (143-1), another one of the above-mentioned pumps (125-1, 125-2) of the pump arrangement (115) with a reduced pumping power (145-1) for pumping washing liquid.

14. The method (200) of claim 12 or 13,

it is characterized in that the preparation method is characterized in that,

the method (200) has the further method steps of:

-in a first time period (143-1) following the second time period (143-2), re-activating (205), by means of the control device (133), one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for pumping washing liquid, in order to pump washing liquid from the respective other line of the pump-out line (117) or the circulation pump line (123), and re-pumping the pumped washing liquid up to the liquid level (135-1) in the pump-out line (117) or up to the liquid level (135-2) in the circulation pump line (123); and is

-in a second time period (143-2) following the first time period (143-1), reactivating (207), by means of the control device (133), another one of the above-mentioned pumps (125-1, 125-2) of the pump device (115) for pumping washing liquid, in order to pump the pumped washing liquid up to a liquid level (135-1, 135-2) in the respective other one of the pump-out line (117) or the circulation pump line (123).

15. The method (200) of any of claims 12 to 14,

it is characterized in that the preparation method is characterized in that,

the method (200) comprises: alternately, in particular periodically, alternately pumping back and forth between a liquid level (135-1) in the pump-out line (117) and a liquid level (135-2) in the circulating pumping line (123), wherein the periodically, alternately pumping back and forth comprises in particular a sinusoidal oscillation.

16. The method (200) of any of claims 12 to 15,

it is characterized in that the preparation method is characterized in that,

the activation (201, 203, 205, 207) of the respective pump (125-1, 125-2) is performed by the control device (133) in a periodically staggered manner with reference to the natural period of the washing liquid column oscillating at the natural frequency between the pump-out line (117) and the circulation pump line (123).