Washing machine

Abstract

The invention proposes to design a washing machine (11) with a first microplastic filter (16) in a drain line (13) and with a second microplastic filter (20) in a circulation line (19) that leads from a tub (3) back to the tub (3). The second microplastic filter (20) filters microplastics from the washing solution multiple times during a wash and rinse cycle.

Description

[0001] The invention relates to a washing machine having the features of the preamble of claim 1.

[0002] Washing machines are generally well-known. As so-called drum washing machines, they have a tub – typically a hollow cylinder – in which a perforated and typically also hollow-cylindrical laundry drum, arranged coaxially within the tub, is driven by an electric motor to rotate around its axis. A solenoid valve allows water to be fed from a water inlet into the tub, to which detergent is added. After washing, the water or washing solution is pumped from the tub into a water drain by a water pump, commonly referred to as a drain pump.

[0003] A lint filter, located in the same direction of flow between the drain container and the drain pump, protects the drain pump from coarse particles. The lint filter is usually accessible for cleaning through a cover on the front of the washing machine's casing.

[0004] In so-called "front loaders", the tub and the laundry drum have a horizontal axis and the laundry drum is open at one front end and accessible through a - usually glass - door in the front of the washing machine's housing for adding and removing laundry.

[0005] In so-called "top loaders," the tub and the washing drum have a vertical or horizontal axis; the tub and the washing drum are open at the top and accessible through a lid on the top of the washing machine's casing.

[0006] The invention is not limited to the above-mentioned designs of washing machines.

[0007] German Patent Application DE 10 2017 215 132 A1 discloses a front-loading washing machine in which a microplastic filter, instead of a lint filter, is arranged between a tub and a drain pump. The purpose of the microplastic filter is to prevent microplastics that detach from laundry items containing synthetic fibers when washing them from being pumped out with the washing solution and thus entering the wastewater.

[0008] Microplastics are particles that are inherently smaller than fibers, lint, fluff, and the like, and which, unlike fibers, lint, fluff, and the like, largely pass through the lint filter of a washing machine. There is an overlap between fibers, lint, fluff, and the like on the one hand and microplastics on the other. Microplastics are understood here to be plastic particles that detach from laundry items containing synthetic fibers during washing in a washing machine, and that have a length between 50 µm and 5 millimeters and a thickness or diameter of no more than 10 µm. A microplastic filter is accordingly a filter that filters out at least 80 to 90% of the microplastics from the washing solution of a washing machine or from any liquid in general. A microplastic filter has a mesh size or pore size of, for example, between 5 and 200 µm.This means that the mesh size or pore size can be larger than the microplastic.

[0009] International patent application WO 2020 / 089 727 A1 discloses a washing machine in which a cylindrical microplastic filter is arranged coaxially behind a lint filter in a cylindrical tubular filter housing. The filter housing is located near the bottom of the washing machine's casing and is accessible for cleaning or replacement, together with the microplastic filter, through a cover at a front end of the filter housing in a front side of the washing machine's casing. A drain pump is also arranged coaxially at a rear end of the filter housing. The microplastic filter is located between the lint filter and the drain pump.

[0010] The object of the invention is to propose a washing machine with improved filtration of microplastics.

[0011] This object is achieved according to the invention by the features of claim 1. The washing machine according to the invention comprises a tub, a drain line, and a first microplastic filter arranged in the drain line. The drain line is connected to the tub such that a washing solution or, in general, a liquid can be removed from the tub. The first microplastic filter filters microplastics from the washing solution, which flows out of the tub through the drain line, is pumped out, or removed in another way before the washing solution or liquid exits the washing machine and, for example, enters a water drain or a wastewater connection.

[0012] Furthermore, the washing machine according to the invention has a second microplastic filter arranged in a circulation line. The circulation line is also connected to the tub and leads back to the tub. The return of washing liquor or, in general, a liquid from the tub back to the tub can improve washing results and / or reduce water consumption. The microplastic filter in the circulation line filters microplastics from the washing liquor or liquid during washing and rinsing. The washing liquor or liquid from the tub of the washing machine is preferably conveyed repeatedly or continuously through the circulation line back to the tub during washing or rinsing, flows through the second microplastic filter, and is filtered in the process, which improves the filtering out of microplastics from the washing liquor or liquid.Fewer microplastic filters from the washing machine end up in a water drain, a wastewater connection or in other ways in the environment.

[0013] The dependent claims relate to advantageous embodiments and further developments of the invention.

[0014] The washing machine according to the invention preferably has a drain pump in the drain line and / or a circulation pump in the circulation line. The drain pump, which can be equated with a so-called drain pump of a conventional washing machine, and the circulation pump are water pumps, which are referred to as drain pumps and circulation pumps for their differentiation and clear designation. The drain pump can be used to remove the washing solution from the washing machine's tub and pump it, for example, into a water drain or a wastewater connection. The circulation pump pumps the washing solution or the liquid from the tub during washing and rinsing through the second microplastic filter back into the tub.

[0015] In one flow direction, the microplastic filters are preferably arranged in front of the pumps, i.e. the first microplastic filter is preferably arranged in the flow direction between the lye container and the drain pump and the second microplastic filter is preferably arranged in the flow direction between the lye container and the circulation pump, specifically on a side on which the washing liquor flows out of the lye container and into the circulation pump.

[0016] To remove coarse particles from the wash liquor, one embodiment of the invention provides a first lint filter upstream of the first microplastic filter in the drain line and / or a second lint filter upstream of the second microplastic filter in the circulation line. A lint filter is understood here to be a filter, sieve, or separator that filters out particles from the wash liquor that are larger than microplastics. The lint filters filter out, for example, 80 to 90% of fibers, lint, and fluff, or, for example, 80 to 90% of particles that are longer than 1 mm or a few millimeters, from the wash liquor. The lint filters keep coarse particles away from the microplastic filters and protect the microplastic filters from damage caused by coarse particles.

[0017] A further development of the invention provides for the microplastic filters to be accommodated in installation spaces provided in the washing machine for lint filters. Equipping the washing machine with the microplastic filters is thus simple and does not require any modifications to the washing machine. There is also no need to arrange the microplastic filters on the outside of the washing machine or outside the washing machine. In this embodiment of the invention, the washing machine has a housing in which the tub is arranged. The washing machine also has a first installation space for the first lint filter and / or a second installation space for the second lint filter within its housing. The microplastic filters are or are arranged in the installation spaces for the lint filters. If the installation spaces are available, the microplastic filters according to the invention do not require any modifications to the washing machine.Preferably, the microplastic filters are housed together with the lint filters or replacement lint filters in the lint filter compartments within the washing machine's housing. For cleaning or replacement, the lint filters and microplastic filters are accessible through openings in the front or top of the washing machine and can be removed from the compartments.

[0018] A preferred embodiment of the invention comprises a first filter control device that checks the permeability of the first microplastic filter and / or a second filter control device that checks the permeability of the second microplastic filter. The filter control device measures, for example, a pressure differential across the microplastic filters, a pressure in an inlet or inlet of the microplastic filter when pumping the washing solution or liquid through, or measures the time required to pump the washing solution from the tub through the microplastic filter. Increasing differential pressure, pressure in the inlet or inlet of the microplastic filters, and / or a longer flow time are an indication of increasing contamination of the microplastic filters.If the differential pressure or pressure at the microplastic filters, or the flow time of the wash liquor or liquid, exceeds a specified or predeterminable value, the microplastic filters must be cleaned or replaced. The second filter control device is sufficient for the permeability of the second microplastic filter in the circulation line, because this microplastic filter becomes contaminated more quickly. The water flows through it several times during washing and rinsing, filtering most of the microplastics and larger particles from the wash liquor before the wash liquor or liquid flows through the first microplastic filter when pumped out of the tub.

[0019] If the permeability of the microplastic filter falls below a predetermined or adjustable value, the washing machine according to the invention preferably issues a filter cleaning, filter blockage message or signal or the like so that the microplastic filters are cleaned or replaced.

[0020] All features mentioned in the description and / or illustrated in the drawings can be implemented individually or in any combination in embodiments of the invention. Embodiments of the invention that include only a portion of the features of a claim, including the independent claim, are possible.

[0021] The invention is explained in more detail below using an exemplary embodiment illustrated in the drawing. The single figure shows a front view of a washing machine according to the invention. The figures are schematic and simplified representations for understanding and explaining the invention.

[0022] The washing machine 1 according to the invention shown in the drawing has a cuboid-shaped housing 2 in which a hollow-cylindrical tub 3 is arranged, in which a likewise hollow-cylindrical washing drum 4 is arranged. The washing drum 4 is arranged coaxially in the tub 3 and can be driven to rotate about its axis by an electric motor 5—in the exemplary embodiment via a belt drive 6.

[0023] In the exemplary embodiment, the washing machine 1 is a so-called "front loader," meaning the laundry drum 4 has a horizontal axis and a rotational axis, and its interior is accessible for inserting and removing laundry items through a door 7 in a front side 25 of the housing 2 of the washing machine 1. For inserting and removing laundry items, the laundry drum 4 and the tub 3 are open at the front ends facing the door 7. In the exemplary embodiment, the door 7 is a porthole-like glass door.

[0024] The washing machine 1 has an inlet line 8, which can be connected, for example, to a faucet 9 of a drinking or service water line 10. The inlet line 8 leads in the housing 2 of the washing machine 1 through a solenoid valve 11 and an inlet box 12 from above to the suds container 3. In the inlet box 12, a detergent can be added to the water in such a way that a washing suds solution is created.

[0025] Furthermore, the washing machine 1 according to the invention has a drain line 13, which is connected to the bottom of the tub 3 and which can be connected to a wastewater connection 14 of a domestic plumbing system. Arranged in the drain line 13—in the housing 2 of the washing machine 1—are a first lint filter 15, a first microplastic filter 16, and a water pump, which is referred to here as a drain pump 18 to distinguish it from a circulation pump 17. The first lint filter 15, the first microplastic filter 16, and the drain pump 18 are arranged in the drain line 13 in the order mentioned, starting from the tub 3. This means that washing liquor or general liquid from the tub 3 flows first through the first lint filter 15, then through the first microplastic filter 16, and then through the drain pump 18.

[0026] Furthermore, the washing machine 1 according to the invention has a circulation line 19, which is connected to the suds container 3 at the bottom and leads back—preferably at the top—to the suds container 3. A second lint filter 20, a second microplastic filter 21, and the circulation pump 17, which is also a water pump, are arranged in the circulation line 19. From the connection of the circulation line 19 at the bottom to the suds container 3 to its return at the top to the suds container 3, the second lint filter 20, the second microplastic filter 21, and the circulation pump 17 are arranged in the circulation line 19 in the order mentioned. This means that the washing solution or general liquid from the suds container 3 flows first through the second lint filter 20, then through the second microplastic filter 21, and then through the circulation pump 17.

[0027] The drain line 13 and the circulation line 19 can be connected together or separately to the bottom of the suds container 3.

[0028] The two lint filters 15, 20 are filters or sieves for fibers, lint, fluff and the like and for coarse particles with a length of, for example, 1 mm or more.

[0029] The two microplastic filters 16 and 21 are filters for microplastics, i.e., plastic particles that detach from laundry items containing synthetic fibers during washing in the washing machine 1 and that have a length between 50 µm and 5 millimeters and a thickness or diameter of no more than 10 µm. The microplastic filters 15 and 21 filter at least 80 to 90% of the microplastics from the washing solution or liquid.

[0030] In the exemplary embodiment of the invention, the microplastic filters 16, 21 comprise filter bags as the filter medium, which are made of a heat-set plastic mesh with an average mesh size in the range between 5 µm and 200 µm. The filter bags are arranged in or on a sieve-like filter basket, which in the exemplary embodiment is cylindrical and which, together with the filter bag, forms the microplastic filter 16, 21 (not shown).

[0031] The circulation pump 17 circulates the washing solution or liquid from the tub 3 of the washing machine 1 according to the invention repeatedly or continuously during a wash or rinse cycle, i.e., it is pumped from the tub 3 through the second lint filter 20 and the second microplastic filter 21 back into the tub 3. As a result, the microplastics are filtered out of the washing solution or liquid in the tub 3 during the washing and rinsing cycles and several times during the washing and rinsing cycles. The multiple filtering achieves a very effective removal of microplastics from the washing solution or liquid in the tub 3 in general.

[0032] After washing and rinsing in the washing machine 1 according to the invention, the washing solution or, in general, the liquid from the tub 3 is pumped by the drain pump 18 through the first lint filter 15 and the first microplastic filter 16 out of the washing machine 1 into, for example, the wastewater connection 14. The first microplastic filter 16 filters out any microplastics still contained in the washing solution or, in general, the liquid.

[0033] The washing machine 1 according to the invention has a first installation space 22—tubular in the exemplary embodiment—for the first lint filter 15 and a second installation space 23—also tubular in the exemplary embodiment—for the second lint filter 20. These installation spaces are arranged in the housing 2 and each has an opening in the front side 25 of the housing 2 through which they can be removed for cleaning or replacement. The installation spaces 22, 23 are sealed in a liquid-tight manner with lids (not shown) on the front side 25 of the housing 2.

[0034] On or in the front 25 of its housing 2, the washing machine 1 also has operating elements 29 and a display 30.

[0035] The two microplastic filters 16, 21 are arranged together with the lint filters 15, 20 in the installation spaces 22, 23 for the lint filters 15, 20 and can be removed from the installation spaces 22, 23 for cleaning or replacement - preferably together with the lint filters 15, 20 - through the openings in the front 25 of the housing 2 of the washing machine 1 according to the invention. It is also possible to arrange one or both installation spaces 22, 23 in the housing 2 of the washing machine 1 with the opening in a top side 26 of the housing 2 such that the lint filters 15, 20 and the microplastic filters 16, 21 are easily accessible from the top side 26 of the housing 2 of the washing machine 1.

[0036] The washing machine 1 according to the invention has a second filter control device 28 for the permeability of the second microplastic filter 20 in the circulation line. The filter control device 28 measures, for example, a pressure increase or a pressure difference at the second microplastic filter 20. "Pressure increase" means an increase in the pressure in the liquid upstream of the microplastic filter 20 as the liquid is pumped through the microplastic filter 20. If the pressure difference or pressure increase is too great, this means that the microplastic filter 20 is "full" and must be cleaned or replaced. According to the invention, the washing machine 1 then issues a preferably visual filter cleaning or filter blockage message.

[0037] The washing machine 1 can also have a first filter control device 27 for the first microplastic filter 16 in the drain line 13, which, like the second filter control device 28, measures, for example, the pressure difference or the pressure increase at the first microplastic filter 16. At this point, it is also possible to measure a pumping time, i.e., the time required by the drain pump 18 to empty the tub 3. If the pumping time is too long, this is also an indication that the first microplastic filter 27 is full.

[0038] Because the second microplastic filter 20 filters more microplastics from the wash liquor, it clogs up more quickly and must be cleaned or replaced before the first microplastic filter 16. The first microplastic filter 16 can be cleaned or replaced at the same time as the second microplastic filter 20, or even every third or fifth cleaning or replacement of the second microplastic filter 20, for example, which is why a design of the washing machine 1 with only one filter control device, in particular the second filter control device 28, is also possible.

Claims

1. Washing machine with a tub (3), a drain line (13) connected to the tub (3), and with a first microplastic filter (16) arranged in the drain line (13), characterized in that the washing machine (1) has a circulation line (19) which is connected to the suds container (3) and which leads back to the suds container (3), wherein a second microplastic filter (21) is arranged in the circulation line (19).

2. Washing machine according to claim 1, characterized in that the washing machine (1) has a drain pump (18) in the drain line (13) and / or a circulation pump (17) in the circulation line (19).

3. Washing machine according to claim 1 or 2, characterized in thatthe washing machine (1) has a first lint filter (15) in a flow direction upstream of the first microplastic filter (16) in the drain line (13) and / or a second lint filter (20) in a flow direction upstream of the second microplastic filter (21) in the circulation line (19).

4. Washing machine according to claim 3, characterized in thatthe washing machine (1) has a housing (2) in which the tub (3) is arranged, and in that the housing (2) has a first installation space (22) for the first lint filter (15) within the housing (2), in which the first lint filter (15) and the first microplastic filter (16) are arranged and / or in that the housing (2) has a second installation space (23) for the second lint filter (20), in which the second lint filter (20) and the second microplastic filter (21) are arranged, and in that the installation spaces (22, 23) have an opening (24) in a front side (25) or a top side (26) of the housing (2), through which the lint filter (15, 20) and the microplastic filter (16, 21) can be removed.

5. Washing machine according to one or more of the preceding claims, characterized in thatthe washing machine (1) has a first filter control device (27) which checks a permeability of the first microplastic filter (16), and / or that the washing machine (1) has a second filter control device (28) which checks a permeability of the second microplastic filter (21).

6. Method for operating a washing machine according to claim 5, characterized in that if the permeability of the second microplastic filter (20) is reduced, a filter cleaning message or a filter blockage message is issued.

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