EP3255195B1 - Method for improving the washing performance of a washing machine and washing machine suitable for this method - Google Patents

Description

The invention relates to a method for operating a washing machine with a tub, a drum arranged therein for receiving items of laundry, a drive motor, at least one water supply device for supplying water to the tub, a pumping system with a drain pump and a pumping line, and a control device in which at least one operating program is stored, the operating program comprising at least one pretreatment phase and a subsequent washing phase. The invention also relates to a washing machine suitable for carrying out the method.

The focus of the research and development of washing machines is moving, in addition to increasing automation of such devices, more and more into the area of sustainable washing machines, which have a good energy and ecological balance. This development is triggered in particular by the enactment of EU standards, which are implemented, among other things, by specifying label programs. Such labels are directly visible to a consumer when buying a washing machine and thus certainly play a major role in a purchase decision.

Particular attention is paid to the energy and water consumption of washing machines. But the efficient use of treatment agents such as detergents also plays a role. Not only because of the existing EU standards, but also for reasons of sustainability and environmental protection, it is therefore desirable to continue to develop energy- and water-saving washing machines.

Energy and / or water-saving washing machines are already known.

1. 1. Nach dem Einlegen des Waschgutes in die Waschtrommel wird diese mit dem trockenen Waschgut zunächst auf eine einen Wäschering in der Waschtrommel bildende Drehzahl gebracht,
2. 2. danach wird die Waschtrommel stillgesetzt,
3. 3. nach dem Stillsetzen der Waschtrommel wird Benetzungsflüssigkeit und ggf. Waschmittel über die Waschmittel-Einspüleinrichtung dem Laugenbehälter zugeführt,
4. 4. die freie Flotte im Sumpf des Laugenbottichs wird bei weiterhin stillgesetzter Waschtrommel auf eine vorgegebene Temperatur erwärmt,
5. 5. nach Erreichen der vorgegebenen Temperatur wird für die Waschtrommel ein Reversiervorgang eingeleitet und das Waschgut wird mit der vorerwärmten Benetzungsflüssigkeit durchfeuchtet,
6. 6. nach der Durchfeuchtungsphase wird die freie Flotte im Sumpf des Laugenbottichs auf die eingestellte Waschprogramm-Endtemperatur aufgeheizt.

The publication DE 197 30 422 A1 describes a method for wetting laundry in a program-controlled washing machine for the household, whose Washing drum is rotatably arranged in a tub, which is equipped with a fresh water inlet, a water level regulator and a detergent dispensing device, the method having the following features:

1. 1. After the laundry has been placed in the washing drum, it and the dry laundry are first brought to a speed that forms a laundry ring in the washing drum,
2. 2. then the washing drum is stopped,
3. 3. After the washing drum has come to a standstill, the wetting liquid and, if necessary, detergent are fed to the tub via the detergent dispensing device,
4. 4. the free liquor in the sump of the tub is heated to a specified temperature while the washing drum is still switched off,
5. 5. After reaching the specified temperature, a reversing process is initiated for the washing drum and the laundry is moistened with the preheated wetting liquid,
6. 6. After the moistening phase, the free liquor in the sump of the tub is heated to the set final washing program temperature.

The publication EP 0 501 240 A1 describes a method for washing laundry in a program-controlled washing machine with a washing drum rotating in a tub and a device for automatic dosing and supply of preferably pumpable detergent components, in which the washing process is divided into a prewash or soaking phase I, a washing phase II and a rinsing phase III is divided and the washing phase II is composed of a heating-up period C for the wash liquor and a post-washing period D, with the laundry in the prewash or soaking phase I during a period A of high washing mechanics and during a period B is exposed to a low washing mechanism and the time segment B with the lower washing mechanism is longer than the time segment A with the higher washing mechanism and after the end of the time segment B with the lower washing mechanism, the heating-up time segment C to reach a preselected or p The program-specific wash liquor temperature begins with the program-specific wash mechanics, and the detergent components for wash phase II are supplied during this heating-up period C.

The publication DE 101 11 081 A1 describes a method for washing laundry in a program-controlled washing machine with a laundry drum moved in a tub, which runs through at least known program sections soaking and main wash one after the other, the average caustic temperature during the main wash being higher than the caustic temperature during the soaking. The main wash program section is carried out before the soak, with the detergent solution from the main wash being used for the soak.

The publication DE 38 11 365 A1 describes a method for reducing the amount of rinsing water, especially in washing machines with an electromagnetic valve for supply water, a pump with a water meter for waste water installed at the pump outlet, with a drive motor, with a regulating and control unit with time and rev counter, with a sensor line for determining the type of laundry and amount and with an input and program selection device for type of laundry, laundry amount and specified spin time. The amount of waste water removed from the laundry after the program step "prewash" by spinning is measured by the water meter, fed to the regulating and control unit as measured variable Q and consequently a variable control time logically linked to the measured variable Q for the electromagnetic valve of the supply water in the rinsing program step of the following Rinse water inlet provided.

1. 1) nach dem Einlegen des Waschgutes in die Waschtrommel wird diese mit dem trockenen Waschgut zunächst auf Schleuderdrehzahl gebracht,
2. 2) mit Erreichen der Schleuderdrehzahl wird Frischwasser über die Einspritzvorrichtung in das Zentrum der Waschtrommel gespritzt,
3. 3) mit Beginn des Frischwasser-Einspritzvorganges wird die Drehzahl der Waschtrommel laufend reduziert,
4. 4) der Frischwasser-Einspritzvorgang wird bis zum Ansprechen des Wasserstandsreglers durchgeführt,
5. 5) nach Ansprechen des Wasserstandsreglers wird die Waschtrommel auf Waschdrehzahl heruntergefahren,
6. 6) mit Erreichen der Waschdrehzahl wird über die Einspülvorrichtung das Waschmittel eingespült,
7. 7) nach Beendigung des Waschmittel-Einspülvorganges wird dem Waschgut weiteres Frischwasser über die Einspritzeinrichtung bis zu dessen Sättigung zugeführt.

The publication DE 40 09 046 C2 describes a method for wetting laundry in a program-controlled drum washing machine for the household, the washing drum of which is rotatably arranged in a tub, which is equipped with a fresh water inlet, a water level regulator, a detergent dispensing device and a washing water injection device, the method having the following features having:

1. 1) after the laundry has been placed in the washing drum, it is first brought to spin speed with the dry laundry,
2. 2) when the spin speed is reached, fresh water is injected into the center of the washing drum via the injection device,
3. 3) with the start of the fresh water injection process, the speed of the washing drum is continuously reduced,
4. 4) the fresh water injection process is carried out until the water level regulator responds,
5. 5) after the water level regulator has responded, the washing drum is lowered to washing speed,
6. 6) When the washing speed is reached, the detergent is washed in via the dispenser,
7. 7) After the detergent dispensing process has ended, the items to be washed are supplied with additional fresh water via the injection device until it is saturated.

The disclosure document DE 1 410 140 describes a method for rinsing laundry in fully automatic washing machines by diluting lye, the lye being gradually diluted by the admission of pure water using inlet and outlet valves, which optionally work together with a suction and pressure pump. After completion of the washing process in continuation of the washing program, the detergent solution drops from its normal level to an adjustable lower level, for example by opening the outlet valve or pumping out. Then the high level is reached again after closing the outlet valve or switching off the pump by filling it with pure water, so that the temperature decreases with increasing caustic dilution and this game can be repeated as often as required. The method described is designed for rinsing the laundry after a washing process has taken place, which is why no washing process can be improved with this method.

The publication EP 1 657 344 A1 describes a method for washing sportswear in a washing machine which includes a laundry drum which is rotatably arranged in a tub. The method includes: a main wash phase including rotating the laundry drum at a main wash speed; a pre-wash phase which is carried out before the main wash phase, the pre-wash phase including washing the sportswear in cold water without any detergent and rotating the laundry drum at a pre-wash speed that is lower than the main washing speed in order to remove dirt that has adhered to the sportswear, to remove; a dirt settling phase, which is carried out after said prewash phase, said dirt settling phase stopping the rotation of the laundry drum and the Includes holding the laundry drum in a stationary position for a predetermined time so that the dirt removed by the pre-wash phase settles on the bottom of the tub; and a water removal phase performed after the soil settling phase, the water removal phase including removing the cold water from the laundry drum. The disadvantage of this process is that the water from the pretreatment phase is completely removed. In other words, the method described is basically a normal prewash program, which can otherwise be used as a program option before a washing program.

1. a) Bereitstellen eines Reservoirs für Waschflüssigkeit;
2. b) Bereitstellen einer Continuous-Batch-Waschmaschine mit einem Innenraum zur Aufnahme von Textilartikeln und einer Vielzahl von Modulen, und einem Einfülltrichter, um das Hinzufügen von Textilartikeln zum Innenraum zu ermöglichen, wobei ein Modul ein Einlassmodul und ein Modul ein Auslassmodul ist;
3. c) Einbringen von zu waschenden Textilstücken in das Einlassmodul;
4. d) Fortlaufender Transfer von Textilstücken von einem Modul zu einem anderen Modul bis die Textilstücke vom Einlassmodul zum Auslassmodul und durch Module mit doppelter Verwendung wandern;
5. e) Pumpen der Waschflüssigkeit vom Reservoir zum Innenraum der Waschmaschine in Schritt (d);
6. f) Gepulstes Strömen der Flüssigkeit zu den Textilstücken für eine ausgewählte Zeitspanne in einem oder mehreren der Doppelverwendungs-Module, welche als Spülmodule fungieren; und
7. g) worin Flüssigkeit vom Einlassmodul zum Einfülltrichter zirkuliert wird.

Ein solches Verfahren eignet sich nicht für eine Trommelwaschmaschine, insbesondere nicht für einen Haushalts-Waschmaschine, welche notorisch als Trommelwaschmaschine ausgebildet ist.The publication US 2013/0291314 A1 describes a method for washing textile pieces, comprising the steps:

1. a) providing a reservoir for washing liquid;
2. b) providing a continuous batch washing machine with an interior for receiving textile articles and a plurality of modules, and a filling funnel to enable the addition of textile articles to the interior, wherein one module is an inlet module and one module is an outlet module;
3. c) introducing textile pieces to be washed into the inlet module;
4. d) Continuous transfer of textile pieces from one module to another module until the textile pieces migrate from the inlet module to the outlet module and through modules with double use;
5. e) pumping the washing liquid from the reservoir to the interior of the washing machine in step (d);
6. f) pulsed flow of the liquid to the textile pieces for a selected period of time in one or more of the dual-use modules, which function as rinsing modules; and
7. g) wherein liquid is circulated from the inlet module to the hopper.

Such a method is not suitable for a drum washing machine, in particular not for a household washing machine, which is notoriously designed as a drum washing machine.

• eine Phase der Behandlung mit Chemie, in welcher eine Behandlungschemie in die Behandlungskammer eingebracht wird, wobei die Behandlungschemie mindestens einen wasserlöslichen Absorber für einen kationischen Farbstoff; ein oberflächenaktives System, welches mindestens ein oberflächenaktives Mittel umfasst; und einen Emulgator umfasst; und
• eine Spülphase, welche der Phase der Behandlung mit Chemie folgt, in welcher der Behandlungskammer eine Spülflüssigkeit zugeführt wird, um die Wäsche der Behandlungschemie zu spülen;

worin während der Anwendungsphase mit Behandlungschemie das mindestens eine oberflächenaktive Mittel in einer Konzentration oberhalb der kritischen Micellbildungskonzentration (CMC) des mindestens einen oberflächenaktiven Mittels anwesend ist.The US 2014/0259441 A1 describes a cycle of operation with reduced dye transfer for a laundry treating appliance with a treating chamber for the Receiving laundry for treatment where the dye transfer reduced duty cycle comprises:

• a phase of treatment with chemistry, in which a treatment chemistry is introduced into the treatment chamber, the treatment chemistry at least one water-soluble absorber for a cationic dye; a surfactant system comprising at least one surfactant; and comprises an emulsifier; and
• a rinsing phase which follows the chemical treatment phase in which a rinsing liquid is supplied to the treatment chamber in order to rinse the laundry of the treatment chemistry;

wherein during the application phase with treatment chemistry, the at least one surfactant is present in a concentration above the critical micelle concentration (CMC) of the at least one surfactant.

The EP 2 703 548 A1 describes a washing machine, comprising a tub outside a rotatable washing drum for receiving laundry, a water supply circuit to provide water in the tub; a supply unit for detergents / rinsing products to provide them in the tub, and a water drain for draining liquid from the tub to the outside. The washing machine has two pumping circuits, one of which conveys liquid from the tub directly back to the tub and the other conveys the liquid from the tub via the detergent / rinsing product supply unit back into the tub.

Against this background, it was the object of the present invention to provide a method for operating a washing machine, in particular a domestic washing machine in the form of a drum washing machine, with improved washing performance with a good ecological balance provide. A treatment phase of an operating program should preferably be improved. For this purpose, sensors should preferably also be able to be used. In addition, a washing machine suitable for carrying out the method is to be provided. The washing machine should preferably operate quietly.

This object is achieved according to this invention by a method and a washing machine suitable for carrying out the method with the features of the corresponding independent claims. Preferred embodiments of the method according to the invention and the washing machine according to the invention are listed in the respective dependent claims. Preferred embodiments of the method according to the invention correspond to preferred embodiments of the washing machine according to the invention and vice versa, even if this is not explicitly stated herein.

The invention thus relates to a method for operating a washing machine with a tub, a drum arranged therein for receiving items of laundry, a drive motor, at least one water supply device, generally for supplying water to the tub, a pumped circulation system with a drain pump and a pumped circulation line, and a control device in which at least one operating program is stored, the operating program comprising a pretreatment phase and a subsequent washing phase, wherein in the pretreatment phase, preferably at the beginning of the pretreatment phase, a first predetermined volume V _start of an aqueous liquid, preferably water, is introduced into the tub, with part of the aqueous liquid being taken up by the laundry items and the part of the aqueous liquid not taken up by the laundry items as free liquor pumped out of the tub by means of the pumping system mpt and is then fed back to it, and wherein the drum is driven at least during the pretreatment phase by means of the drive motor in at least one first drive step, and before the washing phase, generally at the end of the pretreatment phase, a second predetermined volume V _{rem of} the aqueous liquid the tub is pumped out, which is smaller than the volume of the free liquor and is therefore generally not returned to the tub, and wherein in the Washing phase, preferably at the beginning of the washing phase, a third volume V _add of aqueous liquid, in particular water, is fed to the tub.

Furthermore, a load amount of laundry items for a respective operating program is predetermined as a nominal load amount or determined by means of a measuring device, for example a load sensor, the first volume V _start from the product of a load amount in kg and a first load-specific volume V ' _start and / or the second volume V _{rem is determined} from the product of a load in kg and a second load-specific _{volume V 'rem.}

The invention has numerous advantages. In particular, the washing performance of an operating program can be increased by the method according to the invention. Since a proportion of dirt is washed out of the laundry items already in the pretreatment phase and is pumped out with part of the treatment liquid, the washing phase can be made more effective. As a result of the improved washing performance, the overall duration of the operating program can be shortened, which enables particularly energy-saving operation. In addition, an improved washing performance also leads to a more hygienic cleaning of the laundry.

The term "operating program" is to be interpreted broadly. Operating programs include programs that can be carried out as standard in a washing machine, the parameters of which are previously stored in the control device as default values, so-called standard operating programs, as well as operating programs with additional options, i.e. with program parameters modified by a user compared to standard settings. Additional options can be specifications such as a delayed start, a program sequence designed to meet other specifications such as speed, e.g. a washing program that runs as quickly as possible, or a washing program designed for energy efficiency, a hygiene step or, for example, a washing program adapted to individual levels of soiling, such as for blueberry or red wine stains.

In any case, the operating program according to the invention comprises at least one pretreatment phase and a subsequent washing phase, which are automatically followed by the Pretreatment phase is carried out. The operating program is preferably stored as a basic program in the control device, with no further additional options having to be selected in order to select a basic program. Several such operating programs according to the invention can also be stored in the control device, each with different predetermined parameters, which are adapted, for example, to the types of fabric to be washed. Thus, the inventive method can advantageously with only a single setting one for one Tissue type predetermined basic program can be selected by an operator. This also simplifies the operation of the washing machine.

The drum is preferably driven by means of the drive motor in a first drive step for a first time period Δt ₁ at a first speed D ₁ and in at least a second drive step for a second time period Δt ₂ at a second speed D ₂ , the first speed D _{1 being} less than one Application speed at which the items of laundry come into contact with a jacket of the drum, and the second speed D _{2 is} greater than the first speed D ₁ , in particular greater than the application speed. The first and the second driving step are preferably carried out several times. The periods of time Δt ₁ and Δt ₂ thus define the duration of the drive step in which the drive motor is switched on, that is, is rotated. When the drum rotates at a speed lower than the application speed, the items of laundry are lifted inside the drum and fall back to a lower area in the drum, whereby a mechanism that promotes cleaning is advantageously introduced onto the items of laundry. In addition, when the drum rotates at a higher speed, in particular at a speed above the application speed, the laundry items are placed against the jacket of the drum and the liquid absorbed by the laundry is conveyed out or spun out. As a result, the loosened dirt is advantageously carried away from the laundry items together with the liquid that is conveyed out more quickly.

Furthermore, the drum can advantageously rotate in opposite directions, that is to say reversing, it being possible for the first time period Δt _{1 of} the first drive step and the second time period Δt _{2 of} the second drive step to be set differently. In addition, several time periods for the first time period Δt ₁ and second time period Δt ₂ can be stored in the control device for the pretreatment phase and the washing phase, the first and second time periods (Δt ₁ and Δt ₂ ) preferably depending on the type and / or Amount of laundry items to be washed and / or is selected from the selected operating program and / or from a point in time within the pretreatment phase and / or washing phase from the time periods stored in the control device.

Furthermore, it is preferred if at least during one of the two treatment phases, that is to say the pretreatment phase and the washing phase, the direction of the laundry drum is changed generally every 3 to 10 seconds.

The two drive steps can also be carried out in a different order, so that the terms “first” and “second” used here serve in particular to differentiate the content of the two drive steps. However, it is preferred that a first drive step is carried out before a second drive step.

According to the invention, a pretreatment phase is a treatment phase which precedes a washing phase. In the case of operating programs with several washing phases, it is preferred that the pretreatment phase take place before the first washing phase. The pretreatment phase is preferably the first treatment phase, which is run through in an operating program. The term “treatment” here relates to the treatment of the laundry items placed in the drum with an aqueous liquid and / or treatment agents such as, in particular, detergents. The treatment agent is preferably supplied to the tub by means of a metering device for the treatment agent included in the washing machine.

The "pretreatment phase" described herein is thus distinguished from the actual "washing phase" in particular in that aqueous liquid is pumped out between the two phases and, in particular, treatment agent is used in the washing phase, only part of the aqueous liquid not bound by the laundry items being pumped out becomes. The pretreatment phase is preferably carried out without treatment _{agent and an amount M T} of treatment agent is not added to the tub until the washing phase, in particular at the beginning together with the third volume V _add of aqueous liquid. As a result, the washing effect can be increased without additional treatment agents, which saves resources and the environment. Treatment agent can also be fed to the tub in the pretreatment phase, in which case the amount of treatment agent for the washing phase is preferably reduced compared to an operating program with a pretreatment phase without treatment agent. The use of treatment agents in the The pretreatment phase has the advantage that the washing effect can be increased even further in the pretreatment phase.

In the preferred embodiment of the method according to the invention, in which an amount M _PT of treatment agent is fed to the tub at the beginning of the pretreatment phase, the form in which the treatment agent is fed is not further restricted according to the invention. The amount M _PT of treatment agent can, for example, be part of the total amount of the amount of treatment agent provided for the respective operating program, preferably the proportion of which is 0.5 to 5% of the total amount of treatment agent. In this way the total amount of treatment agent remains unchanged. The treatment agent is generally flushed into the tub using an aqueous liquid.

If gray water is fed to the tub in the pretreatment phase, preferably at the beginning, as part or as the entire amount of the volume V _start , then the fact that the gray water generally already contains a small amount of treatment agent can advantageously be used. This takes account of the environmental protection concept in particular, since in this way a treatment agent that has already been dosed once can be used a second time.

The inventors have found that in this way some of the soiling is advantageously washed out of the laundry items in the pretreatment phase. A very small amount of treatment agent can be sufficient for this purpose. A treatment agent usually contains at least one surfactant component (detergent component) which, even in very low concentration ranges, lowers the interfacial tension of water in such a way that a washing effect can be achieved.

In a preferred embodiment of the method according to the invention, at the end of the pretreatment program, the drum is _{stopped for a period of time Δt still} before the volume V _rem of aqueous liquid is pumped out of the tub. In this way it is advantageously made possible that solid dirt particles on the bottom of the Collect the tub and then be pumped out together with the volume V _rem before the start of the washing phase.

In the method according to the invention, a volume V _{rem is} pumped out of the tub at the end of the pretreatment phase. This aqueous liquid is generally discarded and not returned to the tub. With this volume V _rem , part of the dirt washed out of the laundry items, in particular also the insoluble part of the dirt, is transported away, so that a subsequent washing phase can proceed more efficiently, in that the treatment agent in particular can be used more efficiently.

This has two advantages. On the one hand, the dirt in the laundry items is already loosened overall at the beginning of the washing phase following the pretreatment phase, so that the washing performance can be increased in the washing phase. In addition, the washing performance can be further increased by using gray water, since overall, more treatment agents are available for washing out dirt.

In a further preferred embodiment of the method according to the invention, the washing machine used has a heating device and the aqueous liquid is additionally heated in the tub during the pretreatment phase _{to a predetermined temperature value T start} , where T ≤ T _wash preferably applies, where T _{wash is the temperature during the washing phase} means. The heating device is generally arranged in the lower part of the tub. Alternatively, the heating device could also be provided in a circulation line of the washing machine. This has the advantage that the space for the heating device can be omitted in the tub, whereby the free liquor in the tub is reduced. In this way, the amount of liquid required for treatment can advantageously be reduced and thus contributes to conserving resources.

The height of the temperature value T _start, the invention is not limited, but preferably depends on the washing temperature T _wash of the selected operating program, the value T ie _start is either equal to the washing temperature T _wah, approaches this to or at a value below the wash temperature T kept _wash. This ensures that items of laundry for which a certain washing temperature is intended are not damaged by exceeding this temperature. On the other hand, however, the washing performance can advantageously be further increased by heating the aqueous liquid in the pretreatment phase.

The lye pump of the pumping system is usually only switched on after the introduction of aqueous liquid, in particular water, in the pretreatment phase, in particular after the first volume V _{Start has been introduced} into the lye container.

According to the method according to the invention, in the pretreatment phase, generally at the beginning of the pretreatment phase, a predetermined volume V _start of aqueous liquid, in particular water, is introduced into the tub. This can be fresh water, but also process water, which can be stored in the washing machine in the form of gray water, for example, or a mixture of fresh water and gray water. Gray water is understood to mean wastewater that is free of faeces and has a low level of pollution. For example, the liquid of the last rinse cycle of a treatment program of the washing machine could not be pumped into the waste water line, but could be temporarily stored in a container of the washing machine. In a subsequent treatment program, the temporarily stored liquid could be flushed into the tub at the beginning of a pretreatment phase. This has the advantage that fresh water is saved, which saves resources for treating the laundry items. In a preferred embodiment of the method according to the invention, fresh water is supplied to the tub.

In general, the specified first volume V _start is selected such that it is sufficient for wetting and pretreatment of the laundry items. Since the first volume V _start is essentially dependent on the amount of laundry items, called the load quantity for short, the first volume V _{start is determined} as the product of the load quantity in kg and a first load- _{specific volume V 'start} , which is preferably between 2 and 2 , 5 L / kg is selected. Furthermore, a minimum volume for filling waterways of the washing machine and the other structural design of the washing machine must be taken into account. With today's standard designs of Household washing machines, in the preferred embodiment of the method according to the invention, result in the specified first volume V _start 15 to 25 liters, particularly preferably 17 liters, generally based on a capacity of the drum for laundry items in the range of 6 to 10 kg, in particular 7 to 9 kg laundry items , whereby, due to the required minimum volume, a larger specific volume of aqueous liquid may be required in the case of a small load.

For the reasons set out above, the second volume V _{rem is determined} as the product of the load amount in kg and a second load- _{specific volume V 'rem} , which is preferably selected between 0.05 and 0.7 L / kg. Thus, for example, in household washing machines customary today and the preferred specific volume, the second volume V _{rem is} in a range from 0.5 to 4 L, more preferably in a range from 1 to 3 L, based on a capacity of the drum for laundry items in the range of 6 to 10 kg, in particular 7 to 9 kg items of laundry. The second volume V _rem is particularly preferably 2 L. This is the case in particular when fresh water is used for the starting volume at the beginning of the pretreatment phase.

A plurality of values for the second volume V _{rem to be} pumped are preferably stored in the control device, which values take into account, for example, the degree of soiling of the items of laundry and the amount of load in the drum. For this purpose, the washing machine according to the invention can advantageously have sensors which are used to determine these parameters, for example turbidity sensors with which a degree of contamination of the aqueous liquid can be determined.

In a preferred method it is provided that at the beginning of the washing phase a third volume V _add of aqueous liquid, in particular water, preferably an amount M _Twash of treatment agent, which is required for the subsequent washing phase, is supplied to the _{tub with the third volume V add} becomes. The third volume can also be determined as a function of the loading quantity.

The added third volume V _add of water is preferably essentially equal to the second volume V _rem , the ratio V _add / V _rem preferably being in the range from 0.2 to 2, particularly preferably in the range from 0.5 to 1.5, lies. _{V add} V _remin applies very particularly preferably. It is particularly advantageous if the third volume is determined in such a way that the amount of aqueous liquid thus determined is sufficient to supply the treatment agent to the tub.

Furthermore, it is preferred that when using fresh water in an amount of V _start in the pretreatment phase, the third volume V _add is essentially equal to the second volume V _rem . Taking into account the previously described preferred embodiment of the second volume V _{rem , V add} = 2 L results, for example. In this way, the fresh water consumption for the implementation of the entire operating program can be kept low.

However, if, for example, gray water is used as the starting volume, then V _rem preferably assumes a large value.

However, V _add can also be greater than V _rem when using fresh water if, for example, the degree of soiling of the items of laundry and thus the degree of soiling of the aqueous liquid is high. In a preferred embodiment, the degree of contamination of the aqueous liquid can be precisely determined by means of a dirt sensor.

Furthermore, depending on the selected operating program, a maximum volume V _wash of aqueous liquid can be fixed, for example if a total water consumption is not to be exceeded. In such a case, the third volume V _{add is set in} such a way that the maximum volume V _{wash is} not exceeded. Such an embodiment of the preferred method can be used particularly advantageously in a basic operating program or also in an eco program in order to limit the consumption of aqueous liquid to a maximum value.

In a preferred method, the lye pump of the pumping system is generally switched on at least temporarily during the pretreatment phase, so that treatment liquid is pumped out of the lye container at one point and is returned to the lye container and in particular into the drum at another point. The aqueous liquid is preferably pumped out at the bottom of the tub and returned to an upper point of the tub, so that the items of laundry in the drum are exposed to the returned aqueous liquid from above. The point at which pumped treatment liquid is supplied to the tub is also referred to below as the tub inlet of the pumping system.

Alternatively, the treatment liquid can also be returned directly to the drum and thus to the laundry items. In this alternative case, the tub inlet of the pumping system can be arranged in the area of a loading opening of the drum.

In a preferred embodiment of the method according to the invention, the duration of the at least one second time period Δt ₂ , in which the drive motor _{drives the drum at speed D 2} , is in the range from 10 to 30 seconds. The second time period Δt ₂ preferably follows the first time period Δt ₁ , in which the drive motor drives _{the drum at the speed D 1.} In a preferred embodiment of the method according to the invention, this sequence is run through more than once; this sequence is preferably run through at least three times in succession.

The length of the first time period Δt ₁ is otherwise based on the total length of the pretreatment phase. In a particularly preferred embodiment of the method according to the invention, the duration of the pretreatment phase is 15 minutes.

The length of the pretreatment phase can vary depending on the load, the degree of soiling of the items of laundry, the type of textile and the selected operating program. A pretreatment phase is longer with a high load and / or heavy soiling than, for example, for lightly soiled items of laundry or sensitive textiles. This variation can do that The operating program is coordinated particularly well with the textiles to be treated, which enables better resource conservation.

In a preferred embodiment of the method according to the invention, the speed D _{1 is} less than the application speed and is in particular in a range from 30 to 60 1 / min. In this speed range, the effect is advantageously used that the laundry falls into the drum, so that a washing effect can be intensified here by the agitation, ie the input of mechanical energy.

In a further preferred embodiment of the method according to the invention, the speed D _{2 is} greater than the first speed D ₁ and is in particular in a range from 60 to 250 1 / min, particularly preferably in the range from 100 to 230 1 / min. In this speed range, the laundry items generally no longer fall into the drum, so that a spin effect can advantageously be used here. When operating at this speed, part of the aqueous liquid bound by the items of laundry is advantageously spun out and returned to the free liquor. As a result, the laundry is wetted with the liquid more quickly, in particular if the free liquor is pumped around and the laundry items are fed back to the laundry while the drum is rotating. Furthermore, the dirt loosened from the laundry items is advantageously carried away with the liquid from the laundry items, so that even more dirt can be removed when the second volume of liquid is pumped out. Thus then the washing efficiency can be increased even further.

The specified speed values for D1 and D2 apply to a drum diameter for holding items of laundry of essentially 500 mm. If the method is to be used in washing machines which have a drum with a different diameter, the preferred speed values are to be converted proportionally to the diameter.

The invention also relates to a washing machine with a tub, a drum arranged therein for receiving items of laundry, a drive motor, at least one water supply device, a pumping system with a drain pump and a pumping line, and a control device in which at least one operating program is stored Operating program a Pre-treatment phase and a subsequent washing phase, the control device being set up to carry out a method in which, in the pre-treatment phase, a predetermined first volume V _Start of an aqueous liquid, in particular fresh water, is introduced into the tub, in which part of the aqueous Liquid is absorbed by the laundry items and the part of the aqueous liquid not absorbed by the laundry items is pumped as free liquor out of the tub by means of the pumping system and then returned to it, in which the drum is at least during the pretreatment phase by means of the drive motor in at least one first drive step is driven, in which, before the washing phase, a predetermined second volume V _{rem of} the aqueous liquid, which is smaller than the volume of the free liquor, is pumped out of the tub, in which a third in the washing phase tth volume V _add of aqueous liquid is supplied to the tub and in which a load of laundry items for a respective operating program is predetermined as the nominal load or determined by means of a measuring device, the first volume V _start from the product of the load in kg and a first load-specific Volume V ' _start and / or the second volume V _{rem is determined} from the product of the load in kg and a second load-specific _{volume V' rem.}

The first volume V _start can preferably be fresh water and / or gray water at the beginning of the treatment phase. According to the invention, the at least one water supply device is therefore not restricted. Water supply device here means only the possibility of supplying water, ie gray water and / or fresh water, to the tub by means of the device.

The at least one water supply device can comprise, for example, a container for storing gray water, a feed line to the tub and a pump for conveying the gray water. Particularly preferably, the feed line to the tub has a flow sensor for determining the volume of gray water introduced.

The at least one water supply device can also be, for example, a valve-controlled fresh water connection, the valve preferably being provided by the Control device is controllable. Particularly preferably, the fresh water supply line to the tub then additionally has a flow sensor for determining the fresh water volume introduced.

The washing machine preferably has a dorsing device for treatment agents. The metering device is not restricted according to the invention; it is used in any case for metering treatment agent and enables the treatment agent to be flushed into the tub. In a preferred embodiment of the washing machine according to the invention, the metering device is an automatic metering device, which is preferably controllable by means of the control device. In this way, the treatment agent can be dosed as required, so that the resources can advantageously be used for laundry treatment in an even more needs-based and efficient manner.

The drive motor for the laundry drum is also restricted according to the invention only insofar as it has to be suitable for carrying out the method according to the invention.

In a preferred embodiment, the drive motor is a brushless motor. In this way, the method can also be carried out with little noise, which is advantageous in particular when carrying out drive steps at a speed greater than an application speed.

The brushless drive motor can also have a torque sensor that determines the force required to rotate the drum at the respective point in time. In this way, an efficient and thus energy-saving way of working is also possible. The torque can also be determined indirectly by means of the electrical drive parameters and control variables, such as speed, voltage, current, power and / or energy. The load quantity can advantageously also be determined with the torque of the motor. In such a case, an additional load sensor can advantageously be dispensed with.

In a preferred embodiment of the washing machine according to the invention, the washing machine has a dirt sensor. The type of dirt sensor is not restricted according to the invention, but an optical sensor is preferably used which, for example, measures the turbidity of the aqueous liquid, that is to say is a turbidity sensor. The dirt sensor is advantageously arranged in the tub or in the pumping system. In the preferred embodiment, the dirt sensor is used in particular to determine the degree of pollution of the aqueous Liquid in the pre-treatment phase. In this way, the second volume V _rem pumped out at the end of the treatment phase can be adapted particularly precisely to the degree of contamination of the aqueous liquid. For this purpose, a relationship between the degree of contamination of the aqueous liquid and the second volume V _{rem is} preferably stored in the control device.

To determine the second volume V _rem actually pumped out, a flow sensor which is connected to the control device can additionally be arranged in a tub outflow line.

In a further preferred embodiment of the washing machine according to the invention, the washing machine additionally has a load sensor. The load sensor is advantageously arranged in the tub and connected to the control device. The load sensor is preferably used to determine the mass of laundry items in the laundry drum. This enables, in particular, a determination of the loading amount for operating programs, with a total water consumption for the loading amount being specified and stored in the control device. Then, in particular, an exact adaptation of the size of the first volume V _start of aqueous liquid is also possible in the pretreatment phase. This has the advantage that if the loading amount is precisely known, the first, second and third volumes can be selected without exceeding the total amount of water predetermined for the loading amount. This further reduces the resources required for treating the laundry items.

In a further preferred embodiment of the washing machine according to the invention, the washing machine additionally has a heating device for heating the aqueous liquid in the tub and a temperature sensor for measuring the temperature of the aqueous liquid in the tub. Alternatively, the heating device, in particular in the form of a flow heater, can also be arranged in a circulation line. The heating device and the temperature sensor can advantageously be controlled by the control device. In this way, both the temperature T _{Start of} the aqueous liquid in the pretreatment _{phase and the temperature T Wash} in the washing phase can be determined and thus precisely controlled by the control device.

In addition, a high level of washing mechanics that is generated periodically loosens the dirt in the textile fibers so well that the washing performance is further improved in the washing phase that follows the pretreatment phase. Finally, the treatment agent used can be used more efficiently in the washing phase, so that there can also be savings in, for example, washing agents (detergents).

Figur 1

zeigt eine schematische Darstellung einer zur Durchführung des erfindungsgemäßen Verfahrens geeigneten Waschmaschine.

Further details of the invention emerge from the following description of a non-limiting embodiment of a washing machine according to the invention. Reference is made to the Figure 1 .

Figure 1

shows a schematic representation of a washing machine suitable for carrying out the method according to the invention.

The washing machine 1 shown schematically contains a rotatably mounted drum 2 with items of laundry 8 in a tub 3. The washing machine 1 also has a fresh water supply device, which consists of a valve 5 controllable by the control device 4, a flow sensor 15 and a fresh water supply line 6. The fresh water supply line 6 is routed via the dosing device 7 for treatment agent, so that, if required, treatment agent can be flushed from the dosing device 7 into the tub 3 by means of fresh water supply via the fresh water supply line 6.

The drum 2 is driven by the drive motor 11. In this non-limiting embodiment, the drive motor 11 is a brushless and therefore low-noise drive motor 11.

The washing machine 1 also has a pump circulation system consisting of a pump circulation line 9, a tub outlet 10, a tub inlet 14 and a tub 12. By means of the pumping system 9, 10, 12, 14, an aqueous liquid, for example a pretreatment liquid in the pretreatment phase or a washing liquor in the washing phase, can be pumped out of the tub 3 by the drain pump 12 via the tub outlet 10 and via the pumping line 9 and the tub inlet 14 back in the tub 3 to be led back. In this way, circulation of the aqueous liquid is made possible.

The drain pump 12 is also connected to a sewer line 13. A three-way valve, not shown here, which can be controlled by the control device 4, enables the pumping operation to be switched from the pumping system 9, 10, 12, 14 to the sewage line 13. In this way, if necessary, aqueous liquid can be pumped out of the tub 3 and disposed of, in particular also the volume V _rem . Instead of the three-way valve, a second drain pump can alternatively be used.

To carry out an embodiment of the method according to the invention, a volume V _start of 17 L fresh water is introduced into the tub 3 via the fresh water supply line 6 at the beginning of the pretreatment phase. To this end, the control device 4 controls the valve 5. To determine the volume V _{Start introduced} , the fresh water supply line 6 has the flow sensor 15, which is connected to the control device 4.

In this non-limiting embodiment, use is made of the fact that dirt accumulated on the laundry items 8 can be loosened and absorbed by the aqueous liquid through the mechanics generated by the drum rotation and the aqueous liquid.

During the pretreatment phase, if there is sufficient aqueous liquid in the tub 3, the tub 12 is switched on so that the aqueous liquid is circulated through the tub outlet 10 via the pumping line 9 and the tub inlet 14. The tub inlet 14 is arranged in such a way that the items of laundry 8 are exposed to the aqueous liquid from above. This enables a particularly efficient use of the aqueous liquid for wetting and finally for washing the laundry items 8.

In an alternative washing machine, not shown, the tub inlet connected to the circulation line can be at a loading opening of the The tub and the drum, in particular on a cuff arranged between the tub and the housing of the washing machine for sealing the loading opening. With such an arrangement, the aqueous liquid returned to the tub can be brought directly into the drum and thus onto the items of laundry. It is advantageous if the drum is rotated at a speed greater than the application speed, since the returned liquid is then brought onto the items of laundry lying on the jacket of the drum and is pressed through the items of laundry due to the forces acting during the rotation of the drum . This promotes rapid wetting of the items of laundry, detachment and removal of dirt from the items of laundry.

During the pretreatment phase, the drive motor 11 initially drives the drum 2 for a first time segment Δt ₁ = 4 min at a speed D ₁ of 30 1 / min. Then the speed of the drum 2 is increased by the drive motor 11 to D ₂ = 200 1 / min and maintained for a period of time Δt ₂ = 30 s. The sequence Δt ₁ , D ₁ and Δt ₂ , D ₂ is repeated at least twice in this way, it being possible to change the direction of rotation, in particular also during the first time segment Δt ₁ .

After the last time it passes through the period .DELTA.t ₂ with the values of D _2, the drive motor 11 is stopped and thus the drum for a period of time .DELTA.t = 5 min _silent, that is held in position.

A volume V _rem = 2L of the aqueous liquid and thus, in addition to dissolved impurities, in particular also insoluble dirt particles, is then pumped into the sewage line 13 with the aid of the drain pump 12.

After the volume V _{rem has been pumped out} , a volume V _add = 2 L is supplied to the tub 3 via the fresh water supply line 6. The fresh water is passed over the metering device 7 in such a way that the amount of treatment _agent M TWash contained therein is also flushed into the tub 3. Then the washing phase starts.

The numerical values given in this exemplary embodiment apply to an exemplary operating program for treating 8 kg of laundry in a washing machine with a drum diameter of 500 mm.

Reference number

1

Washing machine

2

Drum, laundry drum

3

Suds container

4th

Control device

5

Fresh water supply valve

6th

Fresh water supply line

7th

Dosing device for treatment agents

8th

Laundry items

9

Circulation line

10

Tub outlet

11

Drive motor, brushless drive motor

12th

Drain pump

13th

Sewer

14th

Lye container inlet of the pumping system

15th

Flow sensor

16

Heater

Claims (15)

1. Method for operating a washing machine (1) with an outer tub (3), a drum (2), arranged therein, for receiving items of laundry (8), a drive motor (11), at least one water supply apparatus (5, 6), a repumping system (9, 10, 12, 14) with a drain pump (12) and a repumping line (9), and a control facility (4), in which at least one operating program is stored, wherein the operating program comprises a pre-treatment phase and a subsequent washing phase, wherein in the pre-treatment phase a first predetermined volume V_start of an aqueous liquid, in particular fresh water, is introduced into the outer tub (3),

   - some of the aqueous liquid is absorbed by the items of laundry (8) and the part of the aqueous liquid not absorbed by the items of laundry (8) is pumped out of the outer tub (3) as free liquor by means of the repumping system (9, 10, 12, 14) and is then returned thereto,

   - at least during the pre-treatment phase the drum (2) is driven by means of the drive motor (11) in at least one first drive step,

   - before the washing phase a second volume of the aqueous liquid, which is smaller than the volume of the free liquor, is pumped down out of the outer tub (3),

   characterised in that
   the second volume is a predetermined volume V_rem and that in the washing phase a third volume V_add of aqueous liquid is fed to the outer tub (3),
   and that a load size of items of laundry (8) is predetermined for a respective operating program as a nominal load size or is determined by means of a measuring facility, wherein the first volume V_start is ascertained from the product of a load size in kg and a first load-specific volume V'_start and the second volume V_rem is ascertained from the product of a load size in kg and a second load-specific volume V'_rem.
2. Method according to claim 1, characterised in that at the start of the pre-treatment phase and/or in the washing phase, a quantity M_PT of treatment agent is fed to the outer tub (3) by means of a dosing apparatus for treatment agent (7).
3. Method according to one of the preceding claims, characterised in that at the end of the pre-treatment program the drum (2) is stopped for a period of time Δt_Still before the second volume V_rem of aqueous liquid is pumped down out of the outer tub (3).
4. Method according to one of the preceding claims, characterised in that the washing machine (1) has a heating apparatus (16) and the aqueous liquid in the outer tub (3) is heated up to a predetermined temperature value T_start during the pre-treatment phase.
5. Method according to one of the preceding claims, characterised in that the drum (2) is driven by means of the drive motor (11) in the first drive step for a first period of time Δt₁ with a first speed D₁ and in at least one second drive step for a second period of time Δt₂ with a second speed D₂, wherein the first speed D₁ is lower than an application speed, in which the items of laundry (8) rest against a shell of the drum (2), and the second speed D₂ is higher than the first speed D₁, in particular higher than the application speed.
6. Method according to claim 5, characterised in that the duration of the second period of time Δt₂ lies in the range of 10 to 30 s.
7. Method according to claim 5 or 6, characterised in that the second speed D₂ lies in the range of 60 to 250 1/min, in particular in the range of 100 to 230 1/min.
8. Method according to one of the preceding claims, characterised in that the duration of the pre-treatment phase is less than or equal to 15 min.
9. Method according to one of the preceding claims, characterised in that the first load-specific volume V'_start is greater than or equal to 2L/kg and less than or equal to 2.5 L/g and/or that the second load-specific volume V'_rem is greater than or equal to 0.05 L/kg and less than or equal to 0.7 L/kg.
10. Washing machine (1) with an outer tub (3), a drum (2), arranged therein, for receiving items of laundry (8), a facility for ascertaining or determining a load size of items of laundry (8), a drive motor (11), at least one water supply apparatus (5, 6), a repumping system (9, 10, 12, 14), with an outer pump (12) and a repumping line (8), and a control facility (4), in which at least one operating program is stored, wherein the operating program comprises a pre-treatment phase and a subsequent washing phase, wherein the control facility (4) is configured to carry out a method,

    - in which in the pre-treatment phase a first predetermined volume V_start of aqueous liquid, in particular fresh water, is introduced into the outer tub (3),

    - in which some of the aqueous liquid is absorbed by the items of laundry (8) and the part of the aqueous liquid not absorbed by the items of laundry (8) is pumped out of the outer tub (3) as free liquor by means of the repumping system (9, 10, 12, 14) and is then returned thereto,

    - in which at least during the pre-treatment phase the drum (2) is driven in at least one first drive step by means of the drive motor (11),

    - in which before the washing phase a second volume of the aqueous liquid, which is smaller than the volume of the free liquor, is pumped down out of the outer tub (3),

    characterised in that with the method the second volume is a predetermined volume V_rem and in the washing phase a third volume V_add of aqueous liquid is fed to the outer tub (3) and that the load size of items of laundry (8) is predetermined for a respective operating program as a nominal load size or is determined by means of a measuring facility, wherein the first volume V_start is ascertained from the product of the load size in kg and a first load-specific volume V'_start and the second volume V_rem is ascertained from the product of the load size in kg and a second load-specific volume V'_rem.
11. Washing machine (1) according to claim 10, characterised in that the washing machine (1) has a dirt sensor for determining the degree of contamination of the aqueous liquid.
12. Washing machine (1) according to claim 11 or 12, characterised in that the washing machine (1) has a load sensor.
13. Washing machine (1) according to one of claims 10 to 12, characterised in that the washing machine (1) has at least one flow sensor (15).
14. Washing machine (1) according to one of claims 10 to 13, characterised in that the washing machine additionally has a heating apparatus (16) for heating the aqueous liquid in the outer tub (3) and a temperature sensor for measuring the temperature of the aqueous liquid in the outer tub (3).
15. Washing machine according to one of claims 10 to 14, characterised in that the control facility (4) is configured to carry out a method, in which, a first speed D₁ is driven in at least the first drive step for a first period of time Δt₁ and a second speed D₂ is driven in at least a second drive step for a second period of time Δt₂, wherein the first speed D₁ is lower than an application speed, in which the items of laundry (8) rest on a shell of the drum (2) and the second speed D₂ is higher than the first speed D₁, in particular higher than the application speed.

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