Domestic appliance for guiding a fluid

Abstract

The invention relates to a method for operating a domestic appliance for guiding a fluid, the domestic appliance having a filter unit for filtering the fluid, the fluid being pumped by at least one pump unit, a filter membrane of the filter unit being cleaned by a cleaning unit, the method essentially comprising at least one filtering process, the filtering process comprising at least one first phase and at least one second phase, during the filtering, the fluid flows through the filter membrane in the form of a volume flow, and during the cleaning of the filter membrane, the filter membrane is cleaned by the cleaning unit, in the at least one first phase, the volume flow flows through the filter membrane at a speed v1, and in the at least one second phase, the volume flow flows through the filter membrane at a speed v2, wherein the filter membrane is cleaned in the at least one second phase, and the speed v2 of the volume flow is different from the speed v1 of the volume flow.

Description

Technical Field

[0001] This invention relates to a method for operating a household appliance that guides fluid and to a household appliance that guides fluid.

[0002] In household appliances used for treating laundry, different types of fluids or different fluid-like substances flow within the appliance. In a dryer, the fluid may consist essentially of steam or process air. In the case of a washing machine, the fluid essentially comprises a water-soap mixture, also known as detergent or lye. Both fluids, steam and / or process air, and the water-soap mixture are used in a washer-dryer for cleaning and drying. Furthermore, the fluid may include fabric softener or other laundry treatment agents known to those skilled in the art.

[0003] Similar to washing machines, dishwashers also use a fluid substance, which is also composed of a water-soap mixture and / or process air used to dry dishes.

[0004] During the cleaning and / or drying process, the fluid from the household appliances that guide the fluid, as exemplarily mentioned above, is also mixed with particles dissolved from the processed items. These particles can be, for example, dust and / or food residue, hair, grease, sand, and / or other dirt particles. Furthermore, fibers, especially microplastic fibers contained particularly in wool garments, are shed from the laundry. In this case, the primary focus is on the fibers that are gradually shed from the laundry during these processes. To achieve good cleaning or drying results or to provide an environmentally friendly cleaning and / or drying process, these fibers must be removed from the fluid again.

[0005] These dirt particles or fibers can be filtered by a filtration unit during and / or after the cleaning or drying process. During the cleaning or drying process, one or more pump circulation processes can be performed, in which fluid is circulated by a pump, dirt particles are washed away, and the fluid is reintroduced into the cleaning or drying process. After the cleaning or drying process, a so-called residual fluid rich in dirt particles remains. This residual fluid is generally no longer needed and is separated from the household appliance that directs the fluid. The residual fluid is fed into an outlet or outflow line. Before being fed into the outlet, the fluid is again directed through the filtration unit, thereby reducing or eliminating the entry of dirt particles into the wastewater or wastewater system. Dirt particles are removed separately from the household appliance that directs the fluid. Background Technology

[0006] DE 10 2005 054 684 A1 discloses an apparatus for drying laundry by means of an airflow. In this apparatus, the airflow is guided in a downward direction through a section constructed on the downstream side of a drum. A screen is arranged in this section to remove lint from the airflow. The screen has arched grooves. A scraper is provided for cleaning the screen. The screen is arranged horizontally and has arched grooves in the downward direction. The scraper is spring-loaded on the screen and substantially corresponds to the grooves.

[0007] A position detection unit is disclosed in DE 10 2013 224 968 A1, which identifies whether a filter unit is installed in a laundry handling device and is functioning properly.

[0008] Filtration systems in washing machines are known in particular from document WO 201720725 A1. This document describes a washing machine with a filtration unit arranged between an alkali container and an inlet pipe leading to the alkali container. The filtration unit consists of multiple filter elements arranged side-by-side. Each of these filter elements has a first membrane structure with large pores and a second membrane structure with small pores, wherein the second membrane structure is adapted to filter out microfibers.

[0009] Another document, WO 2013068300 A1, discloses a filter unit for a washing machine or dishwasher. This filter unit has multiple individual filter assemblies, which are arranged either in a row, partially sequentially, or side-by-side. Each filter assembly has a filtrate conduit that substantially directs fluid to an alkaline solution container. Each individual filter assembly has a filter membrane with a different pore size.

[0010] As is known from the aforementioned literature, various filtration systems are known in existing technology for household appliances that guide water, filtering out dirt particles and fibers from the fluid. Because filters become clogged very quickly, forced and continuous cleaning of these filters, especially the filter membrane, is necessary. Summary of the Invention

[0011] The objective of this invention is to design a household appliance for guiding fluids, having a filtration unit that has improved efficiency in terms of filtration and / or cleaning capabilities while also achieving a longer service life.

[0012] According to one aspect of the invention, the objective of the invention is achieved by a method for operating a household appliance that guides fluid, the appliance having a filtration unit for filtering the fluid, wherein the fluid is pumped by at least one pump unit, and wherein the filter membrane of the filtration unit is cleaned by a cleaning unit. The method essentially comprises at least one filtration process, wherein a filtration process includes at least one first stage and at least one second stage, wherein during filtration, the fluid flows through the filter membrane in the form of a volumetric flow, and during cleaning of the filter membrane, the filter membrane is cleaned by a cleaning unit, wherein in at least one first stage the volumetric flow flows through the filter membrane at a velocity v1, and in at least one second stage the volumetric flow flows through the filter membrane at a velocity v2, wherein the filter membrane is cleaned in at least one second stage, and the velocity v2 of the volumetric flow is different from the velocity v1 of the volumetric flow.

[0013] Volumetric flow here refers to a physical parameter derived from fluid dynamics. This physical parameter indicates how much volume of medium is transported through a given cross-section per time interval.

[0014] By using different velocities v1 and v2 of the volumetric flow, in order to achieve the desired processing flow, fluid filtration, and cleaning of the filter membrane, the most suitable fluid quantity for each stage of the filtration process, which includes at least one first stage and at least one second stage, is supplied.

[0015] Advantageously, the at least one second phase is performed before and / or after the at least one first phase.

[0016] The second stage essentially involves cleaning the filter membrane. The more frequently the filter membrane is cleaned, the better and more fluid can be filtered by it. Here, filtration is generally understood as the removal of contaminant particles, such as hair, lint, and fibers, from the fluid, leaving a essentially contaminant-free fluid after filtration. These contaminant particles are primarily deposited on the filter membrane.

[0017] In a filtration process, preferably at least one first time period is provided, during which the volumetric flow flows toward the filter membrane at a first velocity v1. Furthermore, in the filtration process, at least one second time period is provided, during which the volumetric flow flows toward the filter membrane at a second velocity v2, wherein the first and second time periods are implemented in any order.

[0018] The filtration process is divided into two time periods: at least one first time period and at least one second time period. Different velocities are set in the at least one first time period and the at least one second time period, so that the volumetric flow flows at a velocity v1 that is substantially higher than velocity v2. Velocity v1 is essentially present during fluid filtration. This allows for the filtration of large volumes of fluid in a short time. During the at least one second time period, the filtration unit, particularly the filter membrane, is cleaned. To clean the filter membrane as effectively as possible and remove all contaminant particles accumulated on it, the filter membrane must be as flat as possible, meaning it exists flat and is substantially without curvature. Due to the reduced velocity v2, the volumetric flow through the filter membrane is smaller, thereby reducing or preventing membrane deflection.

[0019] Preferably, the velocity v2 of the volumetric flow is less than the velocity v1 of the volumetric flow. By utilizing the lower velocity of the volumetric flow, the volumetric flow has a smaller force or pressure that acts on the filter membrane as it flows through it, thereby reducing the bending or deflection of the filter membrane in the direction of the volumetric flow.

[0020] The lower the velocity of the volumetric flow, the less the flexure of the filter membrane, so that the filter membrane is cleaned by the cleaning unit essentially over the entire filter membrane or on the surface of the filter membrane, wherein the velocity v2 is advantageously essentially 0.

[0021] Advantageously, at least one first stage and at least one second stage are performed at pre-defined time intervals. This means that the volumetric flow is pulsed and, for example, follows at least one first stage followed by at least one second stage and / or vice versa. The at least one first stage is performed at least twice and / or more times in a filtration process. The at least one second stage is performed at least twice and / or more times in a filtration process. By manipulating the volumetric flow through these pre-defined time intervals, a velocity v2 dominates during at least one second stage, which is substantially less than velocity v1 and / or even zero. This substantially prevents flexure or adverse flexure of the filter membrane, allowing the cleaning unit to clean the filter membrane across the entire surface.

[0022] Advantageously, at least one pump unit generates a countercurrent, so that the volumetric flow passes through the filter membrane in the opposite direction, wherein the countercurrent is generated substantially in at least one second stage.

[0023] At least one pump unit essentially comprises a suction mechanism for drawing fluid and / or a pressure mechanism for squeezing or pushing the fluid. The pump unit may consist of a pump device capable of implementing both mechanisms and / or multiple pump devices. Advantageously, one pump device or arrangement of pump devices is provided for each mechanism. Pump devices configured for the suction mechanism are preferably arranged in the region of the front surface of the filter membrane. Pump devices configured for the pressure mechanism are preferably arranged in the region of the rear surface of the filter membrane. The front surface of the filter membrane is the surface on which fluid is first loaded, or the surface from which contaminant particles are filtered or aggregated.

[0024] By generating a countercurrent, the volumetric flow flows in the opposite direction to the volumetric flow flowing at velocities v1 and / or v2. This causes the filter membrane to bend towards the cleaning unit, allowing the cleaning unit to clean the filter membrane substantially without residue. Furthermore, it is possible to ensure that filter cake accumulated on / at the filter membrane is at least partially lifted from the filter membrane by the volumetric flow flowing in the opposite direction or by a reverse volumetric flow.

[0025] Preferably, the pressure on the filter membrane and / or the volumetric flow in the region of the filter membrane is determined by means of a sensor unit, which essentially includes a pressure sensor and / or a volumetric flow measurement sensor, and the velocity v2 is adjusted according to the determined pressure and / or volumetric flow. In other words, the velocity v2 is adjusted according to the sensor signals transmitted or determined by the sensor unit, particularly by the pressure sensor and / or the volumetric flow measurement sensor, in the region of the filter membrane. Other sensors are conceivable.

[0026] Volumetric flow measurement sensors typically measure the volumetric flow or flow rate of fluid passing through, for example, a filter unit. In this invention, the volumetric flow measurement sensor specifically measures the volumetric flow or flow rate that actually flows through the filter membrane.

[0027] The pressure sensor measures the so-called stagnation pressure, which is applied to the filter membrane when volume flow is present. Specifically, the stagnation pressure is measured by taking the difference (Delta) between the value "before" and "after" the flow through the filter membrane. The "stagnation pressure" is defined as the increase in pressure at the stagnation point of the flow-through volume relative to the static pressure of the fluid. In other words, if the measured pressure exceeds a predetermined value, the volume flow or its velocity v2 is adjusted in at least a second stage to reduce the pressure below that predetermined value, thereby substantially preventing membrane deflection during cleaning.

[0028] Another aspect of the invention provides a fluid-guiding household appliance having a filter unit for filtering the fluid. The fluid-guiding household appliance substantially comprises a receiving container, which includes: an inlet opening for fluid and an outlet opening for fluid; at least one pump unit for substantially pumping the fluid; a drive unit for substantially driving the pump unit; and a control unit for operating the drive unit. Furthermore, the fluid-guiding household appliance includes a cleaning unit configured to clean the filter membrane of the filter unit. The fluid-guiding household appliance with the filter unit is adapted to perform the method according to the above aspects, wherein the filter unit is substantially arranged between the inlet opening and the outlet opening of the receiving container, and the inlet opening and the outlet opening are fluidically interconnected.

[0029] This configuration of household appliances that guide fluids enables large volumes of fluid to be effectively filtered at any time, thereby removing contaminant particles from the fluid.

[0030] Preferably, the fluid flows out of the receiving container through the outflow opening, passes through the filter unit, and flows back into the receiving container and / or flows into the outflow line in a filtered manner through the inflow opening. Attached Figure Description

[0031] Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.

[0032] Figure 1 A front view of a household appliance that guides fluid;

[0033] Figure 2 A fluid circulation scheme for a household appliance that guides fluid is shown in a very simplified view;

[0034] Figure 3a A partial side view of the filtration unit of a household appliance with a flexible filter membrane that guides fluid.

[0035] Figure 3b A partial top view of the filter unit of a household appliance that guides fluid;

[0036] Figure 4 A partial side view of a filtration unit of a household appliance with a fluid-guiding membrane in contact with the filter membrane is shown. Detailed Implementation

[0037] exist Figure 1The diagram shows a schematic front view of a fluid-guided household appliance 1, particularly a washing machine 2. The fluid-guided household appliance 1 can be a washing machine, but it can also be a dryer and / or a washer-dryer. Furthermore, the fluid-guided household appliance 1 can also be a coffee maker and / or a dishwasher, but it can also be a refrigeration and / or freezing appliance and / or a refrigeration-freezing combination, wherein ice preparation and ice output, as well as water cooling and water output, are important in the refrigeration or freezing appliance. For simplicity, the fluid-guided household appliance 1 is described below only in the form of a washing machine 2.

[0038] Figure 1 The household appliance 1, which guides fluid, has a front wall 3 for washing machines. A movable inlet shell 5 and a washing machine display unit 7 are substantially arranged on the front wall 3, wherein washing and care substances, such as detergent and / or fabric softener and / or similar substances, can be injected into the inlet shell, and the washing machine display unit allows for the setting of washing programs and process parameters. Furthermore, a washing machine door 9 is provided, which is swingably arranged on the front wall 3, and a cleaning hatch (not shown) is covered by a cleaning hatch cover 11.

[0039] Therefore, in Figure 2 The diagram schematically illustrates a fluid circulation scheme for a fluid-directing household appliance 1, drawn in a highly simplified style. The fluid-directing household appliance 1 has a receiving container 13 for objects to be cleaned and / or dried, such as laundry or dishes. During the cleaning and / or drying process, fluid 14 is located in the receiving container 13. During pump circulation and / or pumping out, fluid 14 is pumped from the receiving container 13 via an outlet opening 17 into the pump circulation or pumping out line 19 by means of a pump unit 15.

[0040] Pump unit 15 is driven by drive unit 21, which is driven or controlled by control unit 23. Drive unit 21 is coupled to control unit 23 via transmission element 25. Pump unit 15 pumps fluid 14 to filter unit 27, where fluid 14 is filtered. After filter unit 27, fluid 14 either flows into outflow line 29 and is separated from the fluid-guiding appliance 1, or flows via return line 31 to inflow opening 33, which guides fluid 14 back to the receiving container 13 of fluid-guiding appliance 1. However, it is also conceivable that fluid 34 is guided, for example, in washing machine 2, through flushing shell 5 and mixed there, for example, with detergent and / or fabric softener.

[0041] exist Figure 3aThe image shows a partial side view of the filter unit 27 of a household appliance 1 that guides fluid. The filter unit 27 essentially comprises a cleaning unit 35 and a filter membrane 39. The cleaning unit includes at least one scraper unit 37, and the filter membrane is configured to filter fluid 14. The scraper unit 37 is substantially abutted against the filter membrane 39, such that the filter membrane 39 is scraped by manipulating the scraper unit 37.

[0042] The scraper unit 37 essentially includes at least one scraper arm 41. Figure 3b In this embodiment, the scraper unit 37 preferably includes three scraper arms 41 substantially constructed on the scraper shaft 43. In a top view of the scraper unit 37, the scraper arms 41 have a curved shape. However, it is also conceivable that the scraper arms 41 are constructed as straight and / or curved. The scraper arms 41 can have any configuration. The scraper unit 37 is substantially rotatably arranged in the filter unit 27. Importantly, the filter membrane 39 is scraped by the rotational movement of the scraper unit 37 and therefore by the rotational movement of at least one scraper arm 41. The term "scraping" is understood to mean that the filter membrane 39 is removed of contaminant particles, so that the membrane surface 45 of the filter membrane 39 is substantially free of contaminants, thereby allowing as much fluid 14 as possible to flow through the filter membrane 39 and be filtered in a short time.

[0043] The scraper unit 37 may have its own drive and / or be driven by an additional drive assembly arranged in the fluid-guiding appliance 1. However, it is also conceivable that the scraper unit 37 is coupled to the drive unit 21 and / or the control unit 23 in terms of control technology.

[0044] Pump unit 15 generates a volumetric flow of fluid 14, which causes fluid 14 to flow toward filter unit 27, particularly through filter membrane 39. As fluid 14 flows through filter membrane 39, contaminant particles are removed.

[0045] exist Figure 3a The embodiment exemplarily illustrates a first stage in which fluid 14 flows through and is filtered via filter membrane 39. Fluid 14 flows out of receiving container 13 and is driven by pump unit 15. Fluid 14 flows toward filter unit 27 in the form of a volumetric flow (arrow V indicates the direction of fluid or volumetric flow). The volumetric flow has a velocity v1 in at least one first stage. Scraper unit 37 is arranged closer to receiving container 13 than filter membrane 39 in the direction of fluid 14 flow. Fluid 14 flows around scraper arm 41 of scraper unit 37 and then flows through filter membrane 39. Dirt particles accumulate on / on the side of filter membrane 39 where scraper unit 37 is arranged.

[0046] Pressure is generated on the filter membrane 39 by the volumetric flow, causing the filter membrane 39 to bend in the direction of the fluid 14 or the volumetric flow. This creates a gap A between the filter membrane 39 and the scraper unit 37, which is referred to below as the deposition space 47. If the scraper unit 37 is to be activated in the second stage of the filtration process, all the dirt particles located in the deposition space 47 will not be scraped off together.

[0047] exist Figure 4 The image shows a partial side view of a filter unit 27 with a fitted filter membrane 39 in a household appliance 1 that guides fluid. Figure 4 In the middle, the scraper unit 3 is attached to the filter membrane 39, so that the filter membrane 39 is almost completely scraped when the scraper unit 37 is activated.

[0048] exist Figure 4 The second stage of the filtration process is particularly shown. The volumetric flow in the second stage has a velocity v2. This velocity v2 differs from the velocity v1 of the volumetric flow in the first stage of the filtration process. The velocity v2 in at least one second stage of the filtration process is preferably less than the velocity v1 of the volumetric flow in at least one first stage of the filtration process. The velocity v2 in at least one second stage of the filtration process is preferably 0. By reducing the velocity v2 of the volumetric flow or by bringing the volumetric flow to a substantially zero velocity v2, it is ensured that the scraper unit 37 adheres to the filter unit 39 to scrape the filter membrane 39 or substantially the entire membrane surface 45.

[0049] Other implementation methods or embodiments may also be considered in order to make the velocity v2 of the volume flow substantially 0 or as small as possible in at least one second stage.

[0050] It is conceivable that at least one first stage and at least one second stage are performed at pre-defined time intervals. This means that the at least one first stage is performed within time period t1, and the at least one second stage is performed within time period t2. As mentioned above, fluid 14 is filtered in the first stage, and the filter membrane 39 is cleaned in the second stage. The order of the at least one first stage and the at least one second stage can be arbitrarily chosen and performed at different frequencies as needed. Preferably, the second stage should be set before and / or after each first stage. In order to filter fluid 14 as much as possible and as quickly as possible, it is suitable that the time period t1 of the at least one first stage of the filtration process is longer than the time period t2 of the at least one second stage of the filtration process. This means that the at least one first stage is implemented for a longer period than the at least one second stage.

[0051] Furthermore, it is conceivable that at least one pump unit 15 generates a backflow (indicated by arrow G in the figures, which shows the direction of fluid flow in the presence of a backflow), causing a volumetric flow to pass through the filter membrane 39 in the opposite direction, wherein the backflow is generated substantially in at least one second stage. This backflow causes the filter membrane 39 to bend "in a sensible manner" toward the scraper unit 37. Thus, the scraper unit 37 is almost permanently pressed against the filter membrane 39, thereby achieving or ensuring good cleaning of the filter membrane 39. The backflow is shown only schematically. If a backflow is present, it is clear that the volumetric flow is essentially zero. This also applies to the backflow when a volumetric flow is present.

[0052] Sensor unit 49, designated by reference numeral 49, includes at least one pressure sensor and / or at least one volumetric flow measurement sensor. Referring also to sensor unit 49 below, sensor unit 49 relates to the aforementioned sensors, pressure sensor and / or volumetric flow measurement sensor. It is conceivable that, with the aid of a pressure sensor (in... Figure 4 (As shown in the diagram) the pressure of the volume flow hitting or impacting the filter membrane 39 is determined, and the velocity v2 is adjusted according to the determined pressure. This means that a sensor unit 49 with a pressure sensor is arranged in the region of the filter membrane 39, which measures the pressure acting on the filter membrane 39 through the volume flow. If the pressure exceeds a predetermined pressure or value, then the pressure sensor of the sensor unit 49 sends a pressure sensor signal.

[0053] Volumetric flow can also be measured using a sensor unit 49 that includes at least one volumetric flow measuring sensor. Here, the volumetric flow measuring sensor measures the volumetric flow flowing through the filter membrane 39. If the volumetric flow measuring sensor obtains a deviating value, a second stage can be introduced, and / or the velocity v2 of the volumetric flow can be adjusted so that the filter membrane 39 can be cleaned according to the above-described criteria, or it can be implemented such that the scraper unit 37 is substantially in contact with the filter membrane 39.

[0054] The volumetric flow measurement sensor can identify whether the filter membrane 39 needs to be cleaned and whether the filter membrane 39 is excessively flexed. The latter is achieved by comparing the flexure of the filter membrane 39 due to its characteristics and material composition at a given flow rate (typically in l / min) of the fluid through the filter membrane 39.

[0055] Pressure sensors and volumetric flow measurement sensors may be included in sensor unit 49 and / or alternatively and / or separately constructed side-by-side. When there is a deviation from the predetermined value obtained by the corresponding sensor in sensor unit 49, a sensor signal is transmitted or output to pump unit 15 and / or drive unit 21 and / or control unit 23. Subsequently, the volumetric flow or its velocity v2 is matched in at least one second stage such that the pressure on filter membrane 39 is placed or brought to a predetermined pressure. This ensures that scraper unit 37 is substantially in contact with filter membrane 39.

[0056] List of reference numerals

[0057] 1. Household appliances for guiding fluids

[0058] 2. Washing machine

[0059] 5. Plunge into the shell

[0060] 7. Display Unit

[0061] 9. Washing machine door

[0062] 11. Clean the hatch cover

[0063] 13. Receiving Container

[0064] 14. Fluid

[0065] 15. Pump Unit

[0066] 17. Outflow opening

[0067] 19. Pump circulation / pumping pipeline

[0068] 21. Drive Unit

[0069] 23. Control Unit

[0070] 25. Transmission element

[0071] 27. Filtering unit

[0072] 29. Outflow pipe

[0073] 31. Return pipeline

[0074] 33. Inflow opening

[0075] 35. Cleaning Unit

[0076] 37. Scraper Unit

[0077] 39. Filter membrane

[0078] 41. Scraper arm

[0079] 43. Scraper shaft

[0080] 45. Membrane surface

[0081] 47. Sedimentation space

[0082] 49. Sensor Unit

[0083] A Spacing

[0084] B. Flow direction of the fluid in volumetric flow

[0085] C. The direction of fluid flow in countercurrent.

Claims

1. Method for operating a domestic appliance (1) for guiding a fluid, the domestic appliance having a filter unit (27) for filtering a fluid (14), wherein, The fluid (14) is pumped by at least one pump unit (15), the filter membrane (39) of the filter unit (27) is cleaned by a cleaning unit (35), wherein the cleaning unit (35) comprises at least one scraper unit (37) which essentially lies against the filter membrane (39) such that by manipulating the scraper unit (37) the entire membrane surface (45) of the filter membrane (39) is brushed and wherein the pump unit (15) generates a volume flow of the fluid (14) which causes the fluid (14) to flow in the direction of the filter unit (27), wherein the method comprises at least one filtration process, wherein the filtration process comprises at least one first phase and at least one second phase, wherein during filtration the fluid (14) flows in the form of a volume flow through the filter membrane (39) and during cleaning of the filter membrane (39) the filter membrane (39) is cleaned by the cleaning unit (35), wherein in the at least one first phase the volume flow flows through the entire membrane surface (45) of the filter membrane (39) with a speed v1 and in the at least one second phase the volume flow flows through the entire membrane surface (45) of the filter membrane (39) with a speed v2, wherein the entire membrane surface (45) of the filter membrane (39) is cleaned in the at least one second phase and the speed v2 of the volume flow is smaller than the speed v1 of the volume flow.

2. The method of claim 1, wherein, The at least one second phase is carried out before and / or after the at least one first phase.

3. The method according to claim 1 or 2, characterized in that, At least one first time period is provided during the filtration process, in which the volume flow flows in the direction of the filter membrane (39) with the speed v1, and at least one second time period is provided during the filtration process, in which the volume flow flows in the direction of the filter membrane (39) with the speed v2, wherein the first time period and the second time period are realized in any order.

4. The method according to claim 1 or 2, characterized in that, The speed v2 is essentially 0.

5. The method according to claim 1 or 2, characterized in that, The at least one first phase and the at least one second phase are carried out in each case at a time interval which can be predefined.

6. The method according to claim 1 or 2, characterized in that, The at least one pump unit (15) generates a counterflow such that the volume flow flows through the filter membrane (39) in the opposite direction, wherein the counterflow is essentially generated in the at least one second phase.

7. The method according to claim 1 or 2, characterized in that, The pressure acting on the filter membrane (39) and / or the volume flow in the region of the filter membrane (39) is determined by means of a sensor unit (49) which comprises a pressure sensor and / or a volume flow measuring sensor, and the speed v2 is adjusted in dependence on the determined pressure and / or volume flow. The at least one second phase is carried out before and / or after the at least one first phase. At least one first time period is provided during the filtration process, in which the volume flow flows in the direction of the filter membrane (39) with the speed v1, and at least one second time period is provided during the filtration process, in which the volume flow flows in the direction of the filter membrane (39) with the speed v2, wherein the first time period and the second time period are realized in any order. The speed v2 is essentially 0. The at least one first phase and the at least one second phase are carried out in each case at a time interval which can be predefined. The at least one pump unit (15) generates a counterflow such that the volume flow flows through the filter membrane (39) in the opposite direction, wherein the counterflow is essentially generated in the at least one second phase. The pressure acting on the filter membrane (39) and / or the volume flow in the region of the filter membrane (39) is determined by means of a sensor unit (49) which comprises a pressure sensor and / or a volume flow measuring sensor, and the speed v2 is adjusted in dependence on the determined pressure and / or volume flow.

8. A domestic appliance (1) for guiding a fluid, having a filter unit (27) for filtering the fluid (14), wherein The fluid-conducting household appliance (1) comprises a receiving vessel (13), wherein the receiving vessel (13) comprises an inflow opening (33) for a fluid (14) and an outflow opening (17) for the fluid (14), at least one pump unit (15) for substantially pumping the fluid (14), a drive unit (21) for substantially driving the pump unit (15), a control unit (23) for operating the drive unit (21), a cleaning unit (35) which is provided for cleaning a filter membrane (39) of the filter unit (27), wherein the fluid-conducting household appliance (1) with the filter unit (27) is adapted to carry out the method according to any one of claims 1 to 7, wherein the filter unit (27) is substantially arranged between the inflow opening (33) and the outflow opening (17) of the receiving vessel (13) and the inflow opening (33) and the outflow opening (17) are fluidically connected to one another, wherein the cleaning unit (35) comprises at least one scraper unit (37) which is substantially applied against the filter membrane (39) such that, by operating the scraper unit (37), the entire membrane surface (45) of the filter membrane (39) is wiped and wherein the pump unit (15) generates a volume flow of the fluid (14) which causes the fluid (14) to flow in the direction of the filter unit (27).

9. The fluid-guiding household appliance (1) as claimed in claim 8, characterized in that The fluid (14) flows out of the receiving vessel (13) through the outflow opening (17) and through the filter unit (27) and back into the receiving vessel (13) and / or into the outflow line (29) through the inflow opening (33) filtered.

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