Washing machine and method for operating a washing machine

Abstract

A washing machine has a drum housing containing a round drum, the inner shape of which is not perfectly cylindrical. The drum maintains a radial distance from the drum housing along its circumference, with the housing designed such that this distance varies continuously and without discontinuity. The distance is smaller at the top of the drum than at its midpoint, and greatest at the bottom, between the lowest point of the drum and one-third of its vertical height. A drain lip may be present at the bottom of the drum to facilitate the removal of water adhering to the outside.

Description

FIELD OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a washing machine and a method for operating such a washing machine.

[0002] WO 2005 / 003268 A1 discloses a washing machine with a so-called flooding system. Water is introduced into a drum located in a drum receptacle not from the outside by partially flooding the drum receptacle, but rather directly into the drum via a pipe through a rotating axis. This allows for a lower water level in the lower area of ​​the drum receptacle. This can reduce foam formation, particularly between the drum receptacle and the drum.

[0003] DE 10 2016 204 347 A1 describes a washing machine with the problem of foam formation during the spin cycle. This results in further problems with draining the wash solution, which contains a large amount of foam. This can lead to a reduction in the drive power of a pump in the washing machine for draining the foam and a decrease in the pump's efficiency. Furthermore, the foam can hardly be pumped out and disrupts the wash cycle. TASK AND SOLUTION

[0004] The invention is based on the object of creating a washing machine as mentioned above and a method for operating the same as mentioned above, with which problems of the prior art can be solved and in particular it is possible to operate a washing machine efficiently and preferably to reduce foam formation during a washing process or during spinning.

[0005] This object is achieved by a washing machine having the features of claim 1 and by a method for operating the same having the features of claim 13 or 14. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are described only for the washing machine or for a method. However, they are intended to be applicable both to such a washing machine and to such a method independently and independently of one another. The wording of the claims is incorporated into the content of the description by express reference.

[0006] The washing machine has a drum for washing laundry therein, wherein the drum is arranged in a drum receptacle so as to be rotatable about a rotation axis. Such a drum receptacle is also generally referred to as a tub. Furthermore, the washing machine has a water guide with a water inlet from an external water supply into the washing machine, with water pipes and valves, and with a water outlet from the washing machine. An inlet device for water into the drum is provided, as well as one or two container drains at the bottom of the drum receptacle through which water can drain from the drum receptacle. The washing machine also has a pump which is connected by water pipes on the one hand to the container drain(s) and on the other hand to the inlet device; it can optionally also have an integrated heating device.It also has a washing machine control system that is connected to the pump, advantageously also with other functional units.

[0007] According to the invention, the outer shape of the drum is round-cylindrical or round, preferably it can even run circularly around a rotational axis of the drum. In contrast, the inner shape of the drum receiving container is not round-cylindrical or it is not round, so that the drum has a radial distance along a circumferential direction of the drum from the drum receiving container, wherein the drum receiving container is designed such that this distance changes continuously in some regions and / or has no discontinuity. In an uppermost region of the drum, the distance is smaller than at the middle vertical height of the drum. In a lower region of the drum, between a lowest point on the drum and one-third of the vertical height of the drum, i.e. approximately in the lower third of the drum receiving container, the distance is greatest.At the lowest point of the drum, the distance is smaller than in the lower part of the drum, which is vertically above the lowest point or adjacent to it at the top. In the circumferential direction, the distance between the drum and the drum receiving container is greatest in front of and behind the lowest point, where one of the container outlets from the drum receiving container is located.

[0008] This design of the distance between the drum and the drum receptacle reduces unwanted foam formation, as water and resulting foam can be collected, especially in the lower area, thanks to the relatively larger distance. Collecting water also reduces the amount of water around the drum, and the water can be quickly drained downwards between the drum and the drum receptacle and, if necessary, drain away, thus contributing less to foam formation.

[0009] In an embodiment of the invention, it can be provided that in the lower region or at the lowest point of the drum, at least one tear-off edge or an upwardly curved tear-off body for water located on the outside of the drum is formed on the inside of the drum receiving container, or the drum receiving container has such a tear-off edge, preferably as a separately formed and attached part. The distance between the drum receiving container and the drum can be smallest at the tear-off edge or at the tear-off body, with this distance being particularly advantageously 5 mm to 20 mm. It can also be less than 5 mm, but if spring action is desired on the drum, it should not be too small to ensure that the drum does not drag or strike against the drum receiving container under any circumstances.The water on the outside of the rotating drum, which is entrained by the rotation and clings to the outside as a film of water, can be scraped off at the separation edge. If the separation edge is positioned close to a container drain, preferably at a distance of less than 10 cm or less than 5 cm, the water can drain away immediately and is thus removed, thus preventing any foam formation. A container drain is preferably positioned upstream of the separation edge in the direction of rotation of the drum.

[0010] In an embodiment of the invention, the tear-off edge can be mirror-symmetrical, in particular with respect to a vertical mirror axis. The vertical mirror axis can run through the rotation axis. Such a symmetrical tear-off edge can achieve the same effect regardless of the drum's rotation direction. In this case, it is preferably provided that a container outlet is provided on both sides of the tear-off edge and at the aforementioned short distance in front of it.

[0011] Advantageously, a valve can be arranged at one or each container outlet on the drum receiving container, particularly advantageously at each of two container outlets. These valves can seal the drum receiving container watertight and airtight. Alternatively, only a single valve can be provided for both container outlets or all container outlets. For this purpose, the container outlets can be joined slightly below the drum receiving container and then connected to the valve.

[0012] In a possible development of the invention, the drum receiving container can be designed to be shape-changing, at least in the lower region, whereby the distance to the drum can be varied over time and in a controlled manner. In this way, it can be changed to suit possible measures to reduce or prevent foam formation. For this purpose, the drum receiving container or its wall can have or consist of non-rigid material, at least in the lower region. Such material can advantageously be elastic plastic or rubber, which also facilitates sealing. The shape of the drum receiving container with regard to its distance from the drum, in particular in the lower region, can be changed by means of actuators. This can take place in particular in the region of the aforementioned tear-off edge, so that the shape of this tear-off edge can also be changed if necessary.For example, it can be small or even not there at all if it is not needed, for example because there is no risk of foam forming or little water is being used at the current stage of the wash cycle. If, on the other hand, foam is starting to form or a lot of water is being used, it can be made larger or higher towards the drum to wipe off water from the outside. This can be done continuously, depending on the required effect. Alternatively, it can be done in two stages or even just in one stage to make control and / or actuators easier. Control is preferably handled by the washing machine control system. The actuators or individual actuators are advantageously designed to be electrically operated, either by means of an electromagnet or an electric motor.

[0013] In one embodiment of the invention, a filter can be arranged behind the tank drain and upstream of the pump, advantageously behind a valve mentioned above, which can be arranged particularly advantageously close to the tank drain or directly behind it. This allows water escaping from the drum receiving container to be filtered, especially before it reaches the pump and could cause problems there. Such filters are known in washing machines. The filter can also be designed to be backwashable. Advantageously, a filter comprises a filter housing and a filter element therein.

[0014] In a further advantageous embodiment of the invention, the washing machine has a dosing device for detergent substances. This can be part of the water supply or connected to it. It can be a conventional drawer in the upper area of ​​the washing machine, and the detergent substances can be flushed along by flowing water on its way into the drum receiving container or into the drum. Alternatively, a dosing device can also be arranged in a water path between the drum receiving container or container drain and the pump, which allows for particularly good and efficient mixing with water.

[0015] In a further embodiment of the invention, a valve can be arranged at the container outlet on the drum receiving container, which seals the drum receiving container in a watertight and airtight manner. In particular, water can be drained from the bottom of the drum receiving container via this valve or not. An air inlet is provided in the upper area of ​​the drum receiving container, which can be sealed airtight using an air inlet valve. Alternatively or additionally, one or more check valves can also be provided at the air inlet, possibly with different flow directions.

[0016] Advantageously, the air inlet in the upper area of ​​the drum container has a cross-section that is larger than the sum of all the container outlets at the bottom of the drum container. This allows foam, for example, to be directed to the air inlet and, in some cases, even removed from the washing machine entirely.

[0017] The air inlet can preferably be arranged in the upper third of the drum receptacle, preferably in the upper fifth. It can particularly preferably be arranged at the uppermost point of the drum receptacle.

[0018] Advantageously, at least one non-return valve is provided in or on the upper region of the drum receptacle or at the aforementioned air inlet. Such a non-return valve can be designed to allow air, water, or foam to escape from the drum receptacle, in particular through to the water outlet. The non-return valve then points out of the drum receptacle. Such foam then no longer causes any problems, particularly if it can be removed from the washing machine via the water outlet. Allowing air to escape can also be advantageous, particularly to prevent a type of pumping inside the washing machine caused by rapidly changing pressure conditions. This can occur when the drum moves due to an imbalance during rapid rotation, for example during spinning.

[0019] An alternative or possible additional check valve can be designed to allow air to pass into the drum receptacle. Its flow direction then extends into the drum receptacle. Preferably, exactly two check valves can be provided in the upper area of ​​the drum receptacle, which are particularly advantageously designed and arranged in opposite directions. Their flow directions are thus opposite.

[0020] Advantageously, a cross-sectional constriction within a check valve or throttle check valve can be fixed or adjustable. If the flow diameter or cross-section is variable, the check valve is either adjustable or adjustable. In controlled check valves or throttle check valves, the cross-section is determined by a reference variable. A combination of an air inlet check valve and a throttle can be used here.

[0021] If the flow diameter is merely statically reduced, the throttle check valve is called an unregulated one-way valve. Optimal adaptation to the specific application is achieved by varying the various sizes (e.g., length and diameter) of the throttle check valve.

[0022] In one embodiment of the invention, the opening cross-section of the two check valves can be different. It can be provided that the opening cross-section of a first check valve with a flow direction out of the drum receiving container is larger than the opening cross-section of a second check valve with a flow direction into the drum receiving container.

[0023] In a method according to the invention for operating a washing machine as described above with a shape-changing tear-off edge, the shape of the tear-off edge can be generally changed in order to influence the removal of water and / or foam from the outside of the drum during its rotation. The tear-off edge can be moved towards the drum or made higher in order to remove more water from the outside of the drum. The tear-off edge can be moved away from the drum or made smaller in order to remove less water from the outside of the drum, for example because this has been recognized as necessary or advantageous. A change in the shape or height of the tear-off edge can be stepped or continuous, as previously explained.

[0024] Furthermore, to reduce foam in the drum, valves on the container drains can be closed completely or at least 50%. This can be done by the washing machine's control system.

[0025] In a further embodiment of the invention, water can be temporarily stored in the filter described above, which is then pumped into the drum as needed. For this purpose, the filter can have a larger volume. This prevents the pump from running dry or starting dry.

[0026] In a method for operating a previously described washing machine with an air inlet in the upper region of the drum receptacle, a valve on at least one container outlet can be opened to pump water out of the drum receptacle. Advantageously, the air inlet valve in the upper region of the drum receptacle is also opened, which can also be achieved by appropriately designed check valves or by the check valve with a flow direction into the drum receptacle.

[0027] To reduce foam in the drum, which would disrupt and negatively impact the washing process, a valve on at least one container drain can be closed completely or at least 50%. This prevents the foam from spreading further through the system or water line, especially toward the pump. This allows the pump to continue operating reliably.

[0028] These and other features emerge not only from the claims but also from the description and the drawings. The individual features may be implemented individually or in combination in an embodiment of the invention and in other fields, and may represent advantageous and individually protectable embodiments for which protection is claimed here. The division of the application into individual sections and subheadings does not limit the generality of the statements made therein. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Further advantages and aspects of the invention emerge from the claims and from the description of exemplary embodiments of the invention, which are explained below with reference to the figures. In the figures: Fig. 1A washing machine according to the invention in a schematic representation, Fig. 2 to 4an enlarged representation of the drum receiving container with drum in different variants. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In the Fig. 1 A washing machine 11 according to the invention is shown in a very simplified manner, comprising a housing 12. The washing machine 11 has a rotatable drum 14 with a rotation axis 15, which is arranged within a drum receiving container 17. The drum receiving container 17 is in the Fig. 2shown in an enlarged view. It has a lower section 17', which merges downwards into a base 17". Just above the base 17" and directly below the drum 14 is a tear-off body 19 that is curved upwards. An upper edge 19' forms, so to speak, the aforementioned tear-off edge. It can be seen that the tear-off body 19 is mirror-symmetrical to a vertical mirror axis, but this need not be the case.

[0031] The washing machine 11 has a water inlet WE and a water outlet WA. A water guide has several water lines I inside the washing machine 11, in which five valves V1 to V5 are also arranged. A water line leads from the valve V1 to a spray nozzle 16 inside the drum receiving container 17 or inside the drum 14, in order to introduce or spray water into the drum 14. A container drain 22 on a water line I2 leads to a valve V3, which is connected to a filter 27. The water inlet WE is connected to the filter 27 by means of a valve V3. By means of another water line, the filter 27 is connected to a pump 25, which in turn is connected to the valve V1 by means of a water line. A dosing device 29 for detergent substances leads into the water line between the filter 27 and the pump 25 by means of a valve V4.This is known from the prior art and requires no further explanation; the addition of detergent substances is not the subject of the present invention. In addition to its filtering function, the filter 27 can also serve as a water volume for the return of water from the drum 14 or from the drum receptacle 17.

[0032] Located at the top of the drum receptacle 17 is a top air inlet 24, which leads to two check valves D1 and D2 via a water line I1 and an air inlet valve V5. The check valve D1 allows water, air, and foam to pass through in a direction away from the drum 14 or the drum receptacle 17, but not in the opposite direction. A corresponding water line leads to the water outlet WA. The check valve D2 allows air to pass through towards the drum receptacle 17, particularly for pressure equalization or ventilation. This air is sucked in through an air inlet LE, which opens into the interior of the washing machine 11. Since its housing 12 is not airtight, air can be sucked in from outside. Air, water, or foam cannot escape in the opposite direction due to the check function. Both check valves D1 and D2 operate in opposite directions, i.e., with opposite flow directions.This allows pressure equalization at the drum receiving container 17, and upwardly escaping foam can be discharged through the check valve D1 to the water outlet WA. The air inlet valve V5 can be used to close the top air inlet 24, in particular to seal it airtight. If the air inlet valve V5 is opened, the two check valves D1 and D2 can operate in opposite directions. The opening cross-section of the check valve D1 is larger than the opening cross-section of the check valve D2. This allows large-volume foam, in particular, to be more effectively discharged through the check valve D1, while the check valve D2 should actually only allow air to enter the system.

[0033] The air inlet valve V5 can be used to close the top air inlet 24, specifically to seal it airtight. When the air inlet valve V5 is opened, the two check valves D1 and D2 can operate in opposite directions. The opening cross-section of the check valve D1 is larger than the opening cross-section of the check valve D2. This allows large-volume foam, in particular, to be more effectively discharged through the check valve D1, while the check valve D2 should only allow air to enter the system.

[0034] A controller 31 is connected to the pump 25, the dosing device 29, and the valve V4, as well as, in a manner not shown, to the other valves for their control. The controller 31 can also be connected to a control device (not shown) for the washing machine and, if necessary, to an electronic converter for a drum drive motor.

[0035] During the washing process, the drum 14 rotates, and washing liquor, i.e., water mixed with detergent substances, is sprayed into the drum 14 via the spray nozzle 16. The composition of the washing liquor can be adjusted by the control unit 31 via the dosing device 29. Valve V1 can be used to set whether the washing liquor is introduced into the drum 14 or pumped out of the washing machine 11 via the water outlet WA. Valve V2 allows the water flow from the drum 14 to be shut off via the container drain 22 back into the filter 27 and thus back into the circuit.

[0036] The check valve D1 is used to allow air, water, or foam to escape from the drum 14 or the drum receptacle 17 to the outside via the top air inlet 24, line I1, and valve V5 if there is excess pressure or too much foam in the drum 14 or the drum receptacle 17. This excess foam can cause the washing process to have to be stopped until the foam slowly breaks down or collapses. Operating the pump 25 with too much foam in the circuit is not possible, or at least very problematic. Air, water, or foam can also be discharged down to the water outlet WA. The check valve D2 is blocked in this case. The opposite-direction check valve D2 allows air into the drum receptacle 17 or into the drum 14. This allows any negative pressure there to be equalized. However, air, water, or foam cannot escape here.If foam builds up during the washing process, for example due to incorrect detergent dosage, excessively high speed or possibly too little laundry in the drum 14, i.e. due to excessive washing mechanics due to, on the one hand, excessively high speed of the drum 14 and / or, on the other hand, too little laundry load, the foam can escape to the outside via line I1 through the check valve D1 when the air inlet valve V5 is open. In particular, the foam escapes into the water line to the water outlet WA. The valve V2 can support this process by being closed or by regulating an air flow depending on the amount of laundry in the drum 14, the speed of the drum 14 and the amount of water available in the system.

[0037] The top air inlet 24 is designed to facilitate foam drainage. Thus, the opening cross-sections at the bottom of the drum receiving container 17 can be smaller overall than those at the top or at the top air inlet 24. Additionally, the water flow and air flow can be regulated via valves V2 and V5.

[0038] To achieve a stable condition, fresh water can be supplied from the outside at the water inlet WE via valve V3. The wash liquor can also be partially removed from the system via valves V2 and V1 using the pump to the water outlet WA. This also allows the concentration of detergent in the water in the system to be adjusted. At the same time, the speed of drum 14 can be reduced, and pump 25 can be used exclusively for pumping out foam or wash liquor.

[0039] Once the foam has been sufficiently reduced, air exchange can be achieved again via the check valve D2 alone. Nothing more then needs to escape from the drum receptacle 17 through the check valve D1.

[0040] From the enlarged view of the Fig. 2the non-circular shape of the drum receptacle 17 is easier to see. The distance between the inside of the drum receptacle 17 and the drum 14 is smallest in the upper area below the top air inlet 24, but increases evenly to the left and right. In the lower area 17' of the drum receptacle 17, the distance is approximately twice as large as at the top. Due to the special shape of the drum receptacle 17 in this lower area 17', the distance quickly becomes much larger again before the lower area 17' merges into the base 17". The tear-off body 19 is located on this base 17". The tear-off edge formed by the upper edge 19' leads, as can be seen from the arrows illustrating the water flow, to a greater extent of water being removed from the outside of the drum 14, as explained at the beginning. This is the function of a tear-off edge.This water first escapes through small openings in the drum 14, as is known to exist. Thus, container drains 22a and 22b are formed on the left and right sides of the demolition body 19, which merge into a drain line 23. As previously explained, valve V2 is located in one of these drain lines 23. This allows water to be selectively drained from the drum's receiving container 17, but possibly also allows air to be admitted or discharged.

[0041] The Fig. 3 shows a similar structure for a drum receiving container 17, whereby two drain lines 23a and 23b, each with a valve V2a and V2b, are provided in the lower area 17' behind the container drains 22a and 22b. Such separate drainage allows for additional functionality.

[0042] Regarding the tear-off body 19, it should also be noted that the drum 14 is round-cylindrical or circular-cylindrical in the plane of the drawing. Similarly, the tear-off body 19 should have a cylindrical or constant cross-section in the direction parallel to the rotation axis 15. Thus, the distance between the tear-off body 19 or the upper edge 19' on the one hand and the drum 14 on the other hand is always the same.

[0043] In the Fig. 4 is based on the representation of the Fig. 2a further alternative embodiment of the invention is shown. The shape of the drum receiving container 17 is the same as previously described. The tear-off body 19, on the other hand, is adjustable or variable, in particular height-adjustable. This can be achieved by connecting an adjusting actuator 20 to the upper edge 19' by means of an adjusting rod 21. This allows it to be brought into an upwardly curved shape (shown in dashed lines), in which it reaches very close to the drum 14. The distance here can be between 5 mm and 15 mm. Accordingly, the adjusting actuator 20 can also move the upper edge 19' downwards using the adjusting rod 21, thus making the tear-off body 19 flatter, for example into the shape shown in dashed lines. The distance to the drum 14 is then greater than, for example, in the upper region of the drum 14. The adjusting actuator 20 can be controlled accordingly by the controller 31 for this purpose.It can have an electric motor or an electromagnet for operation.

Claims

1. Washing machine comprising: - a drum for washing laundry therein, - a drum receptacle in which the drum is arranged to rotate about a rotation axis, - a water guide comprising: + a water inlet from an external water supply into the washing machine, + water pipes and valves, + a water outlet from the washing machine, + an inlet device for water into the drum, + at least one container drain at the bottom of the drum receptacle, + a pump connected by water pipes on the one hand to the container outlet and on the other hand to the inlet device, + a washing machine control system to which the pump is connected, characterized in that: - the outer shape of the drum is round-cylindrical or round, preferably circular around a rotational axis of the drum, - the inner shape of the drum receiving container is not round-cylindrical oris not round, - the drum has a radial distance along a circumferential direction of the drum to the drum receiving container, wherein the drum receiving container is designed such that this distance: + changes continuously in some areas and / or has no discontinuity, + is smaller in an uppermost area of ​​the drum than at the middle vertical height of the drum, + is greatest in a lower area of ​​the drum between a lowest point of the drum and a third of the vertical height of the drum, + is smaller at the lowest point of the drum than in the lower area of ​​the drum which lies above the lowest point in the vertical direction, + is greatest in the circumferential direction in front of and behind the lowest point between the drum and the drum receiving container, wherein the container outlet from the drum receiving container is arranged here.

2. Washing machine according to claim 1, characterized in thatin the lower region or at the lowest point of the drum of the drum receiving container, a tear-off edge is formed for water located on the outside of the drum, wherein preferably the distance from the drum receiving container to the drum is smallest at the tear-off edge, wherein in particular the tear-off edge is formed mirror-symmetrically to a vertical mirror axis.

3. Washing machine according to claim 1 or 2, characterized in that a valve is arranged at each of the two container outlets on the drum receiving container, wherein the valves preferably seal the drum receiving container in a watertight and airtight manner.

4. Washing machine according to one of the preceding claims, characterized in thatthe drum receiving container is designed to be variable in shape in the lower region, wherein the drum receiving container preferably has or consists of non-rigid material in the lower region, wherein the shape of the drum receiving container is variable with respect to a distance of the drum receiving container to the lower region of the drum by means of electrically operated actuators, in particular in the region of the tear-off edge according to claim 2.

5. Washing machine according to one of the preceding claims, characterized in that a filter is arranged behind the tank drain and in front of the pump.

6. Washing machine according to one of the preceding claims, characterized by a dosing device for detergent substances which is part of the water supply or is connected to the water supply.

7. Washing machine according to one of the preceding claims, characterized in that- a valve is arranged on the container outlet on the drum receiving container, which seals the drum receiving container in a watertight and airtight manner, - an air inlet is arranged in the upper area of ​​the drum receiving container, - the air inlet can be closed airtight by means of an air inlet valve.

8. Washing machine according to claim 7, characterized in that the air inlet in the upper area of ​​the drum receiving container has a cross-section that is greater than or equal to the sum of all cross-sections of the container outlets at the bottom of the drum receiving container.

9. Washing machine according to claim 7 or 8, characterized in that the air inlet is arranged in the upper third of the drum receiving container, preferably in the upper fifth, in particular at the uppermost point of the drum receiving container.

10. Washing machine according to one of the preceding claims, characterized in thatat least one non-return valve is provided at the upper region of the drum receiving container, wherein preferably a non-return valve allows air and / or foam to pass out of the drum receiving container, in particular towards the water outlet.

11. Washing machine according to claim 10, characterized in that a further check valve is provided at the upper region of the drum receiving container, in particular at the air inlet, which allows air to pass into the drum receiving container, wherein preferably exactly two check valves are provided in the upper region of the drum receiving container, which are arranged in opposite directions.

12. Washing machine according to claim 11, characterized in thatan opening cross-section of the two check valves is different, wherein preferably an opening cross-section of a check valve with a passage direction out of the drum receiving container is larger than an opening cross-section of a check valve with a passage direction into the drum receiving container.

13. A method for operating a washing machine according to any one of claims 7 to 12, characterized in that For pumping water out of the drum receptacle, a valve is used to open at least one container outlet from the drum receptacle, whereby the air inlet valve in the upper area of ​​the drum receptacle is also opened.

14. A method for operating a washing machine according to any one of claims 7 to 12, characterized in that To reduce foam in the drum, a valve is used to close at least one container drain completely or at least 50%.

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