Washing machine and method for operating a washing machine

Abstract

A washing machine has a drum (14) for washing laundry and a drum housing (17) in which the drum (14) is rotatably mounted about a pivot axis and at the bottom of which a drain (22) is provided. A valve (V2) is arranged at the drain (22) on the drum housing (17), which seals the drum housing (17) at the bottom in a watertight and airtight manner. An air inlet is provided in the upper part of the drum housing (17), which can be sealed airtight by means of an air inlet valve and two counter-clockwise arranged check valves.

Description

SCOPE 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] From WO 2005 / 003268 A1, a washing machine with a so-called recirculation system is known, in which water is not introduced into a drum located in a drum housing from the outside by partially flooding the drum housing, but directly into the drum through a rotating axis. This allows for a lower water level in the lower part of the drum housing, thereby reducing foam formation.

[0003] German patent DE 10 2016 204 347 A1 discloses a washing machine with a problem of foam formation during the spin cycle. This results in a further problem for pumping out the wash water, which contains a large amount of foam. This can lead to a reduction in the pump's drive power and thus a decrease in its efficiency. Additionally, the foam can be difficult to pump out and disrupts the washing process.

[0004] From US patent 2018 / 298538 A1, a washing machine is known with a drum in a drum housing that rotates around a vertical axis. Accordingly, access to the drum is provided from above, which can be closed with a corresponding lid. The drum housing is equipped with a drain at the bottom, which can be closed by means of a drain valve.

[0005] US patent 2005 / 0011234 A1 describes another washing machine with a drum housing in which a drum is rotatably mounted, but around a horizontal axis. Access to the drum is from the front of the washing machine via a familiar door. It can be assumed that this door provides a watertight and airtight seal to the drum housing.

[0006] From US 2014 / 0283312 A1, CN 113564880 A and DE 1911523 U, further washing machines with a drum emerge, each having a drum in a drum container, a device for introducing water into the drum and a container drain at the bottom of the drum container. TASK AND SOLUTION

[0007] The invention is based on the objective of creating a washing machine and a method for operating it, 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.

[0008] This problem is solved by a washing machine with the features of claim 1 and by a method for operating it with the features of claim 9. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. Some of the features are described only for the washing machine or for the method. However, they should be able to apply independently to both such a washing machine and to such a method. The wording of the claims is incorporated into the description by express reference.

[0009] The washing machine comprises a drum for washing laundry, a drum housing in which the drum is rotatably mounted about a pivot axis, and a water system. The water system includes a water inlet from an external water supply into the washing machine, water pipes and valves, a water outlet from the washing machine, a water inlet device for the drum, at least one drain at the bottom of the drum housing, a pump connected by water pipes to both the drain outlet and the inlet device, and optionally a filter for filtering the water flowing through it. Furthermore, the washing machine has a control unit connected to the pump, advantageously to all controllable functional units of the washing machine.

[0010] According to the invention, a valve is arranged at the outlet of the drum receiving container, which seals the drum receiving container watertight and airtight; 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 by means of an air inlet valve. Additionally, according to the invention, one or more check valves are provided here, optionally with different flow directions.

[0011] Advantageously, the air inlet in the upper part of the drum housing has a cross-section that is larger than the sum of all the cross-sections of the drains at the bottom of the drum housing. This allows, for example, foam to be drawn towards the air inlet and, if necessary, even completely removed from the washing machine.

[0012] The air inlet can preferably be arranged in the upper third of the drum receiving container, preferably in the upper fifth. It is particularly preferred that it be arranged at the very top of the drum receiving container.

[0013] According to the invention, at least one check valve is provided in or on the upper part of the drum housing or at the aforementioned air inlet. Such a check valve is designed to allow air and foam to escape from the drum housing, particularly through the water outlet. One direction of flow through the check valve is outwards from the drum housing. This prevents such foam from causing problems, especially if it can be removed from the washing machine via the water outlet. Releasing air can also be advantageous, particularly to avoid a kind of pumping action within the washing machine caused by rapidly changing pressure conditions. These can occur when the drum moves due to an imbalance during rapid rotation, for example, during the spin cycle.

[0014] A further possible check valve can be designed to allow air to pass into the drum receiving container. Its flow direction then points into the drum receiving container. Preferably, exactly two check valves can be provided in the upper region of the drum receiving container, which are particularly advantageously designed and arranged in opposite directions. Their flow directions are therefore opposite.

[0015] Advantageously, the 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, it is a controllable or adjustable check valve. In controlled check valves or throttle check valves, the cross-section is determined by a reference variable. This can involve a combination of an air inlet check valve and a throttle.

[0016] If the flow diameter is simply reduced statically, the throttle check valve is called unregulated. Optimal adaptation to the specific application is achieved by varying the different dimensions (e.g., length and diameter) of the throttle check valve.

[0017] 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.

[0018] In a method for operating a previously described washing machine, a valve on at least one outlet of the drum container is opened to pump water out. Advantageously, the air inlet valve in the upper part of the drum container is also opened, which can also be achieved by appropriately designed check valves or by a check valve with a flow direction into the drum container.

[0019] To reduce foam in the drum, which would disrupt and negatively affect the washing process, a valve on at least one container drain can be completely or at least 50% closed. This prevents the foam from spreading further within the system or water flow, especially towards the pump. This ensures the pump can continue to operate reliably.

[0020] These and other features are evident not only from the claims but also from the description and the drawings, whereby the individual features, either alone or in combination, may be implemented in one 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 general validity of the statements made therein. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages and aspects of the invention will become apparent from the claims and from the description of exemplary embodiments of the invention, which are explained below with reference to the figure. The figure shows Fig. 1 A washing machine according to the invention in schematic representation. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0022] In the Fig. 1In a highly simplified form, a washing machine 11 according to the invention is shown with a housing 12. The washing machine 11 has a rotatable drum 14 with a pivot axis 15, which is arranged within a drum housing 17. The washing machine 11 has a water inlet WE and a water outlet WA. A water guide system has several water lines l inside the washing machine 11, in which five valves V1 to V5 are also arranged. A water line leads from valve V1 to a spray nozzle 16 inside the drum housing 17 or inside the drum 14 to introduce or spray water into the drum 14. A container drain 22 to a water line l2 as a drain line 23 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.The filter 27 is connected to a pump 25 via a further water line, which in turn is connected to the valve V1 via another water line. A dosing device 29 for detergent substances introduces water into the water line between the filter 27 and the pump 25 via a valve V4. This is known from the prior art and does not require further explanation; the dosing 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 reservoir for the return of water from the drum 14 or from the drum receiving container 17.

[0023] At the top of the drum housing 17 is a top air inlet 24, which leads via a water line l1 and an air inlet valve V5 to two check valves D1 and D2. Check valve D1 allows water, air, and foam to pass in one direction away from the drum 14 or the drum housing 17, but not in the opposite direction. A corresponding water line leads to the water outlet WA. Check valve D2 allows air to pass towards the drum housing 17, particularly for pressure equalization or ventilation. This air is drawn in through an air inlet LE that opens into the interior of the washing machine 11. Since its housing 12 is not airtight, air can be drawn in from the outside. Due to the check valve function, air, water, or foam cannot escape in the opposite direction. 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. Furthermore, any foam escaping upwards 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, and in particular 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 check valve D1 is larger than the opening cross-section of check valve D2. This allows particularly large volumes of foam to be discharged more effectively through check valve D1, while check valve D2 is intended to allow only air into the system.

[0024] A control unit 31 is connected to the pump 25, the dosing unit 29, and the valve V4, as well as, in a manner not shown, to the other valves for their control. The control unit 31 can also be connected to an operating unit (not shown) for the washing machine and, if necessary, to an inverter for a drum drive motor.

[0025] During the washing process, the drum 14 rotates, and washing solution, i.e., water mixed with washing-active substances, is sprayed into the drum 14 via the spray nozzle 16. The composition of the washing solution can be adjusted by the control unit 31 via the dosing device 29. Valve V1 determines whether the washing solution is introduced into the drum 14 or pumped out of the washing machine 11 to the water outlet WA. Valve V2 allows the water flow from the drum 14, via the container drain 22, back into the filter 27 and thus back into the cycle.

[0026] The check valve D1 allows air, water, or foam to escape from the drum 14 or the drum hopper 17 to the outside via the top air inlet 24, line l1, and valve V5 if there is overpressure or excessive foam in the drum 14 or drum hopper 17. This excess foam can necessitate stopping the washing process until the foam gradually dissipates or collapses. Operating the pump 25 with too much foam in the circuit is either impossible or extremely problematic. Air, water, or foam can also be discharged to the water outlet WA. In this case, the check valve D2 is closed. The reverse check valve D2 allows air into the drum hopper 17 or the drum 14, thus equalizing any negative pressure within it. However, air, water, or foam cannot escape through this opening.If foam forms during the washing process, for example due to incorrect detergent dosage, excessive spin speed, or possibly insufficient laundry load in drum 14—that is, due to excessive washing action caused by both excessively high drum speeds and / or insufficient laundry load—the foam can escape to the outside via line l1 through the non-return valve D1 when the air inlet valve V5 is open. Specifically, the foam escapes into the water line leading to the water outlet WA. Valve V2 can assist this process by closing or by regulating the airflow depending on the amount of laundry in drum 14, the drum speed, and the amount of water in the system.

[0027] The design of the top air inlet 24 is such that foam drainage is facilitated. Thus, the opening cross-sections at the bottom of the drum receiving container 17 can be smaller in total than those at the top or at the top air inlet 24. Additionally, water flow and air flow can be regulated via valves V2 and V5, respectively.

[0028] To achieve a stable state, fresh water can be supplied from the outside via valve V3 at the water inlet WE. The washing solution can also be partially removed from the system to the water outlet WA via valves V2 and V1 using the pump. This allows the detergent concentration in the system water to be adjusted. Simultaneously, the drum speed 14 can be reduced, and pump 25 can be used exclusively for pumping out foam or washing solution.

[0029] Once the foam has been sufficiently reduced, air exchange can again be achieved solely via the check valve D2. Nothing then needs to escape from the drum receiving container 17 through the check valve D1.

Claims

1. A washing machine (11) comprising: - a drum (14) for washing laundry therein, - a drum-receiving container (17) in which the drum (14) is rotatably arranged about a rotational axis (15), - a water flow system which has: + a water inlet (WE) from an external water supply into the washing machine (11), + water pipes (11, l2, 23) and valves (V1 - V5), + a water outlet (WA) from the washing machine (11), + a feed device (16) for feeding water into the drum (14), + at least one container drain (22) at the bottom of the drum-receiving container (17), + a pump (25) which is connected by means of water pipes (12, 23) to the container drain (22) on one side and to the feed device (16) on the other side, + a washing machine controller (31) to which the pump (25) is connected, - a valve (V2) is arranged at the container drain (22) on the drum-receiving container (17) and is designed to seal the drum-receiving container (17) in a watertight and airtight manner, - an air inlet (24) is arranged in the upper region of the drum-receiving container (17), characterized in that - the air inlet (24) can be sealed in an airtight manner by means of an air inlet valve (V5), it being possible to open and close the air inlet valve (V5), - at least one check valve (D1, D2) is provided on the upper region of the drum-receiving container (17) in addition to the air inlet valve (V5), - the check valve (D1) allows air and foam to pass through it out of the drum receiving-container (17).

2. The washing machine according to claim 1, characterized in that the air inlet (24) in the upper region of the drum-receiving container (17) has a cross section that is greater than or equal to the sum of all cross sections of the container drains (22) at the bottom of the drum-receiving container (17).

3. The washing machine according to claim 1 or 2, characterized in that the air inlet (24) is arranged in the upper third of the drum-receiving container (17).

4. The washing machine according to claim 3, characterized in that the air inlet (24) is arranged in the upper fifth of the drum-receiving container (17), in particular at the topmost point of the drum-receiving container (17).

5. The washing machine according to one of the preceding claims, characterized in that the check valve (D1) allows air and / or foam to pass through it out to the water outlet (WA) from the drum-receiving container (17).

6. The washing machine according to one of the preceding claims, characterized in that at least one further check valve (D2) is provided on the upper region of the drum-receiving container (17), which valve allows air to pass through it into the drum-receiving container (17).

7. The washing machine according to one of the preceding claims, characterized in that exactly two check valves (D1, D2) are provided in the upper region of the drum-receiving container (17), which valves are arranged in opposite directions.

8. The washing machine according to claim 6 or 7, characterized in that the opening cross section of the two check valves (D1, D2) is different, the opening cross section of a check valve (D1) with a flow direction out of the drum-receiving container (17) preferably being greater than the opening cross section of a check valve (D2) with a flow direction into the drum-receiving container (17).

9. A method for operating a washing machine (11) according to one of the preceding claims, characterized in that in order to pump water out of the drum-receiving container (17), a valve (V2) on the at least one container drain (22) out of the drum-receiving container (17) is opened, the air inlet valve (V5) in the upper region of the drum-receiving container (17) also being opened additionally.

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