Patent Application
20240279861
This application claims priority to German Application No. 10 2023 201 349.5, filed Feb. 16, 2023, the contents of which are hereby incorporated herein in its entirety by reference.
The invention relates to a method for operating a washing machine and to such a washing machine, wherein the method is primarily concerned with drenching items of laundry in the washing machine with water in a controlled manner and to the desired extent.
It is known from US 2022/145517 A1 to drench laundry with water in a washing machine not in a partially filled drum receptacle as is conventional in the prior art, but instead to apply water from above into the drum and onto the items of laundry. In this way, water can be applied more directly onto the items of laundry. Less water is required overall, as the drum receptacle around the drum does not first have to be filled to a specific level so that the items of laundry can as it were soak up water from below.
The object of the present invention is to provide a method for operating a washing machine as stated above and a washing machine suitable therefor, with which prior art problems can be solved and it is in particular possible to make drenching laundry or items of laundry simple and practical and preferably also possible to carry out in a precisely controllable manner.
This object is achieved by a method for operating a washing machine having the features of claim 1 and by a washing machine having the features of claim 22. Advantageous and preferred embodiments of the invention are the subject matter of further claims and are explained in greater detail below. Some of the features are only described for the method or only for the washing machine. Regardless of this, however, they are intended to be applicable separately and mutually independently both to such a method and to such a washing machine for carrying it out. The wording of the claims is incorporated by express reference into the content of the description.
The washing machine of the invention has a drum receptacle in which a drum for accommodating laundry or items of laundry is rotatably arranged therein, wherein a drive motor for the drum is provided for the rotation thereof. It has a power supply for the drive motor, preferably with power electronics or in the form of an inverter. It has an injection device, either in the upper region on the drum receptacle or close to a door or in a door seal. Water is introduced or injected into the drum from above using the injection device. The drum receptacle has a drain with drain valve, preferably at the bottom. The drain may be closed by way of the drain valve in such a way that the drum receptacle can be filled with water at least in a lower region. Drenching may thus be carried out from below as known.
The washing machine has a water routing system with water lines, valves, a fresh water inlet into the washing machine, a waste water drain from the washing machine, a pump, the drum receptacle, the drain from the drum receptacle, sensors and the injection device. Further means such as for example filters, water tanks or the like may additionally be provided. It furthermore has a washing machine controller which is connected to the power supply for the drive motor and to the valves and pump for driving them.
The steps described below are carried out in the method according to the invention. First, in a step A, a dry weight of items of laundry is detected in the drum, for example by way of a weighing means on the washing machine or on the drum or on the drum receptacle. This may alternatively take place by rotating the drum with the items of laundry therein and monitoring and evaluating a motor current of the drive motor. A laundry/water ratio which is to be achieved, i.e. as it were a degree of drenching of the items of laundry, is furthermore specified. This can preferably be specified by a washing program or washing process set on the washing machine by a user and be dependent on the washing program, i.e. differ, for example, in terms of washing temperature and, above all, the nature of the items of laundry, in particular in terms of fiber type.
In a subsequent step B, with the drain valve open, water is introduced from below through the drain into the drum receptacle and into the drum with the items of laundry therein, preferably via the fresh water inlet, wherein the water pressure prevailing at the fresh water inlet is advantageously used or sufficient for this purpose. In this case, no water needs to be pumped by the pump. A water level in the drum receptacle or in the drum may amount to a few cm, advantageously less than 10 cm and more than 2 cm, such that the lower items of laundry are in the water and thus drenched or can absorb water. The volume of water introduced via the fresh water inlet is detected or known, possibly by way of a flow sensor or a volumetric flow sensor as it flows through, or alternatively by detecting a water level in the drum receptacle or for example in the above-stated filter. Then, either after or during the introduction of water, the drum is rotated slowly or in a plurality of substeps, preferably by a total of exactly one revolution. This ensure that constantly different items of laundry or regions of items of laundry are immersed in the water located at the bottom and are thus wetted or drenched.
In a subsequent step C, water, advantageously via the fresh water inlet or fresh water from outside, is applied from above onto the items of laundry in the drum by way of the injection device. Since at least some of the items of laundry are drenched, the laundry will at least partially collapse, creating a free space in the upper region of the drum, the drum no longer as it were being completely filled to the top. In this upper region, the injection device can apply water onto the items of laundry. The drain from the drum receptacle is here closed by way of the drain valve and the drum is preferably not rotated. In so doing, the volume of water introduced via the injection device may be detected, advantageously in a similar manner to that previously described by way of a flow sensor or volumetric flow sensor at the fresh water inlet. By closing the drain, it is possible to ensure that any water escaping downward from the items of laundry remains in the drum receptacle and can contribute to drenching the items of laundry from below. According to one option, provision may be made for the water previously introduced into the drum receptacle from below to be drained away and, for example, temporarily stored, preferably in the filter which may be arranged downstream of the drain valve. The two volumes of water can then be kept separate from one another.
In a subsequent step D, the drum with the items of laundry therein is rotated by way of the drive motor, advantageously at a relatively low speed of rotation or a speed of rotation of 70 rpm to 100 rpm. This relatively low speed of rotation should be selected such that items of laundry are also present in the region of an axis of rotation of the drum or exactly on the axis of rotation, i.e. in the central region of the drum. The intention is thus to ensure that items of laundry do not largely rest against the inner wall of the drum due a higher or relatively high speed of rotation and to prevent a free tunnel without items of laundry in it from forming around the axis of rotation. In this step D, the drain valve is advantageously open and the presence of water and the volume of water draining away through the drain can be detected. Since the total volume of water introduced into the washing machine and onto the items of laundry is known as previously described, and it is now also known how much water has drained out of the drum receptacle, it is possible to determine how much water is in the laundry or has been absorbed by the items of laundry by simply calculating the difference.
In a subsequent step E, the drum is again not rotated while, with the drain valve closed, water is applied from above onto the items of laundry by way of the injection device. The items of laundry are thus rewetted, specifically again from above.
In a subsequent step F, the procedure is similar or even identical to that as previously in step D in that the drum is rotated while the drain valve is open in order to allow water to drain away from the drum receptacle through the drain. Again, the volume of water draining or drained away through the drain is detected, advantageously as previously described.
In a subsequent step G, the total overall volume of water introduced into the drum and applied onto the items of laundry or the total volume of fresh water admitted into the washing machine and the volumes of water drained away through the drain are detected and compared, in particular the volume of water most recently drained away through the drain. This determines how much water has been absorbed by the items of laundry in the drum or how much water is in the items of laundry. The remaining fresh water admitted into the washing machine must then have drained out through the drain. This water may for example be collected in the above-stated filter thanks to the large volume thereof and this volume of water can then be determined. If the ratio of this volume of water absorbed by the items of laundry to the weight of the items of laundry present in the drum does not yet correspond to the specified laundry/water ratio from the above-stated step A, water is again applied from above onto the items of laundry by way of the injection device. Water still present in the water routing system may be used for this purpose, or alternatively further fresh water could be supplied. If need be, this can be repeated until the specified laundry/water ratio has been achieved.
In a subsequent step H, a specified washing process for the items of laundry begins as soon as the ratio of the volume of water absorbed by the items of laundry in the drum to the weight of the items of laundry present in the drum corresponds to the laundry/water ratio from step A corresponding to this specified washing process. The items of laundry then have the level of drenching appropriate to or specified for this washing process in accordance with the specified ratio.
In one development of the invention, a quantity of additive, in particular laundry detergent, required for a washing process can be calculated on the basis of the volume of water known to be present in the washing machine and the known water absorption of the items of laundry, i.e. their level of drenching. The settings of a washing program set or selected for the washing process may be factored in for this purpose. A specified quantity of additives may accordingly be achieved for a specified level of drenching. The washing process can thus take place as optimally as possible.
In a further development of the invention, a point in time for addition of the additives, in particular of the laundry detergent, during the washing process, can be adjusted and thus optimized. This can also be based on the fact that the volume of water in the washing machine or in the drum and in the items of laundry present therein as well as the weight of the items of laundry are known. The time for which the additive acts can accordingly be optimized.
In one advantageous development of the invention, between individual steps B to H, the items of laundry can be rearranged or tumbled in accordance with step B. This advantageously takes place by moving the drum in accordance with step B. The drum's direction of rotation can particularly advantageously be reversed here. Such a reversal in the drum's direction of rotation can in general be provided at intervals in order to loosen up the items of laundry better and/or distribute them more evenly. A speed of rotation can be set as previously described.
In one development of the invention, the introduced volume of water can be set such that the weight of the items of laundry is twice to five times that of the weight of the introduced water. This can thus correspond to a specified laundry/water ratio of 2:1 to 5:1. In this range, items of laundry are considered to be drenched, either with a high degree of drenching close to a ratio of 2:1 or with a low degree of drenching close to a ratio of 5:1.
In one development of the invention, water can be introduced permanently and uniformly into the drum receptacle during step B, wherein the drum is either permanently moved or, on rotation in substeps, stops for at most 0.5 seconds to 5 seconds after each 10° to 45° rotation of the drum. This occurs in particular after each 20° to 35° rotation of the drum. Thanks to the avoidance of rapid rotation of the drum, the items of laundry are tumbled or rearranged without water being spun out of them.
In a further development of the invention, after step B and before step C, the drum can be rotated in the opposite direction to step B, i.e. the direction of rotation can be reversed as stated above. The drum is here advantageously rotated slowly or in a plurality of substeps as previously described.
In one possible development of the invention, water can be introduced into the washing machine in step C as fresh water from outside in addition to the water introduced in step B. Alternatively, only water which has already been admitted into the washing machine may be used for drenching the items of laundry from above, but this is of course only possible if sufficient water has drained out of the drain.
In a further development of the invention, it is advantageously possible in step D to use a tunnel sensor device to detect whether items of laundry are present in the region of the axis of rotation of the drum or exactly on the axis of rotation. This should be avoided or, if such is the case, the speed of rotation should be reduced somewhat, at least until items of laundry are present there again. A speed of rotation of 70 rpm to 100 rpm as already mentioned above can in many cases fulfill this condition. The tunnel sensor device may advantageously be configured such that it operates optically. Particularly advantageously, it can take the form of a light barrier or reflection light barrier with a direction of illumination along the axis of rotation or parallel to the axis of rotation. Alternatively, it may have a camera and be provided or operated with appropriate image processing.
In an advantageous further development of the invention, in step D, the drum can be rotated at a speed of rotation which is 5% to 50%, preferably 10% to 30%, below that speed of rotation at which a region of 3 cm around the axis of rotation of the drum is free of items of laundry. It can thus be ensured that the speed of rotation is below a speed of rotation at which a distinct tunnel forms in the items of laundry in the drum. Provision may here be made for the drum to be rotated and the speed of rotation increased until a region of 3 cm around the axis of rotation of the drum is free of items of laundry and/or remains free of items of laundry for a period of at least 3 seconds to 10 seconds. This can be detected by way of the tunnel sensor device. Starting from this point, the speed of rotation can then be reduced again by 5% to 50% or by 10% to 30% as desired. If the stated region around the axis of rotation of the drum only remains free briefly or for a few seconds until this has been identified by the sensor device, and then items of laundry are present there again by reducing the speed of rotation, there is no negative impact.
In a further development of the invention, the drain valve can be opened in step D and/or in step F, wherein the volume of water then draining away from the drum receptacle through the drain is determined. No water should be added by whatever route to the drum or onto the items of laundry during this draining The volume of water flowing away through the drain can advantageously be identified via an appropriately configured volume sensor, for example a capacitively or optically operating sensor. In one development of the invention, the volume sensor can be arranged on or in a filter downstream of the drain through which the water flows downstream of the drain and is filtered. The volume sensor may be a filling level sensor and advantageously a plurality of filling level sensors can be provided on or in the filter. These may preferably be capacitively operating sensors or turbidity sensors. The volume of water can accordingly be determined by a specific filling level being achieved. Alternatively, a flow rate sensor as known from the prior art may be provided.
In the stated step E, the water present in the water routing system can first be applied onto the items of laundry by way of the injection device. This may continue for as long as a laundry/water ratio specified in step A is not yet achieved. Water can then be admitted into the fresh water inlet, wherein the applied water may be drawn from the water routing system or from a reservoir arranged in the water routing system. In each case, it is important for the volumes of water to be detected and known, such that it is always known in total how much water has been admitted into the washing machine and how much water has not been absorbed by the laundry but is present separately, for example stored in the above-stated filter. It is accordingly always possible to calculate the difference which is then present in the laundry in accordance with the laundry/water ratio. For the purposes of achieving the specified laundry/water ratio, the motor current of the drive motor can in general additionally be monitored in order to determine the weight of wet items of laundry in the drum. If the weight of the dry items of laundry is known, it is thus possible additionally to determine the weight and thus the volume of water in the items of laundry for verification.
These and further features are found in the description and in the drawings as well as in the claims, wherein the individual features can each be realized singly or severally in the form of sub-combinations in one embodiment of the invention and in other fields, and can represent embodiments advantageous and protectable per se, for which protection is claimed here. The subdivision of the application into individual sections and sub-headings does not limit the statements made thereunder in their general validity.
Further advantages and aspects of the invention can be found in the claims and in the description of exemplary embodiments of the invention that are explained in the following on the basis of the figures, in which:
The schematically illustrated washing machine 11 with a washing machine controller 12 has a drum 13 with a drive motor 14. As is conventional, the drum 13 is arranged in a drum receptacle 15, also denoted tub. At the bottom, a drain 17 leads out of the drum receptacle 15, downstream of which is arranged a drain valve Vl. A filter 20 is arranged downstream of the drain valve V1, which filter advantageously has different filter stages, particularly advantageously is configured for coarse filtering and fine filtering. Appropriate filter screens or the like are arranged in a large housing of the filter 20. A filling level sensor 21 is schematically arranged on the filter 20; advantageously, there may be a plurality of filling level sensors which can identify different filling levels of the filter 20 and thus different volumes of water.
A water line 22a leads from the filter 20 to a pump 24 with a heater 25. Corresponding pumps are known as “motor heating pumps”. A further water line 22b leads from the pump 24 to a feed line valve V2 which takes the form of a three-way valve. A water path leads to a waste water drain 27 from the washing machine 11 to the outside for pumping water out of the washing machine 11. Another water path leads by way of a feed line 29 to an injection device 31 at the top of the drum receptacle 15. Such injection devices for washing machines are also known, in particular for “recirculation” washing machines. The injection device 31 may for example be arranged close to a door or a door seal. Under certain circumstances they may be configured to be controllable or adjustable in their injection direction. An above-stated tunnel sensor device, advantageously on or in the drum 13, is not shown but is readily conceivable. This too can possibly be arranged close to the door or close to a door seal.
At the bottom left, a fresh water inlet 33 leads into the washing machine 11. A first flow sensor 34 is mounted on its water line. This flow sensor 34 can detect the volume of water which has flowed through the line. This is used, in addition or alternatively to a measurement with the filling level sensor 21, to detect the volume of water admitted into the washing machine 11 or present therein. A fresh water valve V3 is used to control the supply of fresh water. The admitted fresh water first enters the filter 20. From there, in can flow onward to the pump 24, in particular in order to be injected from above into the drum 13 as water F onto the items of laundry W via the injection device 31. Alternatively, the water can be admitted into the bottom of the drum receptacle 15 through the drain valve V1 and the drain 17 in order to wet items of laundry W in the drum 13 from below.
The washing machine controller 12 is here schematically connected only to the drive motor 14, the pump 24 and the feed line valve V2. In practice, of course, it is connected to all functional units and sensors. Furthermore, it is either connected to a separate weighing device of the washing machine 11 in order to determine the weight of the items of laundry W in the dry state. Alternatively, this can be achieved by evaluating a motor current at the drive motor 14 or at its driver or power supply.
In phase 2 according to
Using the steps described above for calculating or determining the laundry/water ratio, it is possible to determine this ratio until has been achieved. The appropriate washing program or washing process can then be started with the items of laundry optimally wetted for this purpose. This may not only save time and water, but advantageously prevent excessively dry or wet items of laundry. This could disrupt a washing process or lead to an inadequate washing result, which can be avoided with the invention.
The drum 13 then stops, the drain valve V1 is closed, while the fresh water valve V3 is opened for a period of time t3. Possibly assisted by the pump 24 or solely under water pressure, water is admitted in circulation and, according to step C, sprayed from above onto the items of laundry W by way of the injection device 31. According to
Next, according to step F, the drain valve V1 is opened again and the volume of water flowing out through the drain 17 is detected. The water may have been expelled or spun out of the items of laundry W by rotation. By rotation of the drum at a low speed of rotation, for example below 100 rpm, the items of laundry can be tumbled in order to modify or loosen up the density of the textiles. It may be noted that steps C and E, and D and F are similar.
The drum then stops. Then, according to step G, the laundry/water ratio or degree of wetting for a specific washing program is calculated or determined on the basis of the previously detected volumes of water. If this corresponds to the specified value, see step A, then according to step H either wetting can be considered to have been achieved and completed and a specified washing process for the items of laundry, for example a full wash cycle or a delicate wash cycle, can begin. If the ratio does not yet correspond to the specified value, i.e. the laundry is still inadequately wetted or drenched, then it is best to continue with step C or step E by admitting more water or using available water and in any event wetting the items of laundry.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 201 349.5 | Feb 2023 | DE | national |
