IT202100017543A1 - FILTER GROUP FOR WASHING MACHINE - Google Patents

Description

DESCRIPTION

Field of application

[0001] The present invention relates to a filter assembly for a washing machine. Furthermore, the present invention relates to a washing machine comprising said filter assembly.

[0002] In particular, the present invention relates to the domestic and/or industrial washing sector of fabrics and consequently of fabric products, such as for example garments. In further detail, the present invention directs its attention to the washing of synthetic fabrics, ie fabrics which in their entirety, or in a portion thereof, are made of polyester, polypropylene, polyamide and/or acrylic. In still further detail, the present invention directs its attention to washings in which synthetic fabrics are washed simultaneously with fabrics made at least partially of natural fibers, such as for example cotton or linen or wool.

[0003] In particular, with the term ?washing machine? it also generically means a washer-dryer.

State of the art

[0004] In the state of the art are known a plurality of washing machine solutions whose operation of washing operations ? well known.

[0005] ? It has been ascertained that in known washing machines, during the washing operations of the fabrics, these fabrics produce fibers of micrometric dimensions which are discharged into the exhaust systems and therefore into the environment, polluting it. In particular, the production of microfibers ? mostly due to the washing method, the action of the spin cycle (and in particular to the increasingly high spin speeds), the type of detergent, the hardness of the water, etc.

[0006] The washing of synthetic fabrics involves the production of synthetic microfibres. These synthetic microfibres are not biodegradable and therefore cause water pollution by microplastics (by which term we mean particles/fibers characterized by a length of less than 5mm or even 1mm).

[0007] The increase in items of clothing in synthetic fabrics has led to the diffusion of the quantity of synthetic microfibers of micrometric dimensions in the waste water and therefore in the environment, causing greater environmental pollution. In particular ? an increase in synthetic particles/microfibres of micrometric dimensions, i.e. having a length of less than 5 mm, has been observed in the waters.

[0008] In the state of the art, also in the name of the same Applicant, solutions of filter units for washing machines have been disclosed which have the specific aim of carrying out filtration operations on synthetic microfibres.

[0009] The problem that ? been found in these known solutions? linked to the fact that typically natural fiber fabrics, such as cotton, are also washed together with synthetic fabrics. In other words, in addition to synthetic microfibres, natural fibers are also present in waste water. Given the particular nature of fabrics in natural fibers, such as cotton, or linen or wool, the fibers released by these fabrics have dimensions and shapes among the most? different. In some cases, natural fibers are in the order of a micrometre, ie they have dimensions substantially similar to those of synthetic microfibres, while in other cases they have dimensions in the order of a nanometre.

[00010] ? It has been verified that the different characteristics of natural fibers compared to synthetic microfibres lead to an acceleration of clogging of the microfiber filter, requiring maintenance/replacement of the filter unit.

[00011] In particular, ? It has been verified that these natural fibers agglomerate creating aggregates of fibers which obstruct the flow of water through the filter unit.

Solution of the invention

[00012] Due to the above? The need to solve this problem is strongly felt by supplying a filter group which effectively filters the waste water after the washing operations of synthetic and/or natural material fabrics, preferably cotton, linen and/or wool, not requiring frequent maintenance and replacement operations.

[00013] The object of the present invention is, therefore, to provide a new filter unit for a washing machine and a new washing machine comprising this filter unit which satisfy this requirement.

[00014] This purpose? achieved by means of a filter unit in accordance with what is claimed in claim 1. Similarly, this aim is achieved by a washing machine claimed in claim 18.

Description of the drawings

[00015] Further characteristics and advantages of the invention will appear from the following description of preferred embodiments thereof, given by way of non-limiting example, with reference to the attached figures in which:

[00016] - figure 1 shows a perspective view of a filter unit in accordance with the present invention;

[00017] ? figures 2, 2a and 2? respectively show a side view, a rear view, and a view along the sectional plane A-A of Figure 2, of a filter unit, according to a preferred embodiment of the present invention;

[00018] ? figures 3 and 3a show a longitudinal sectional view and a perspective view of some components of a filter unit according to a preferred embodiment in accordance with the present invention;

[00019] ? figures 4 and 4a show a longitudinal sectional view and a perspective view of some components of a filter unit according to a further preferred embodiment in accordance with the present invention;

[00020] ? figures 5 and 5a show a longitudinal sectional view and a perspective view of some components of a filter unit according to a still further preferred embodiment in accordance with the present invention;

[00021] ? Figure 6 and Figure 6a respectively illustrate a perspective view broken away and a longitudinal sectional view of the filter assembly in accordance with the present invention, according to another embodiment;

[00022] ? Figure 7 shows a perspective view with separate parts of a filter unit in accordance with the present invention, in a variant embodiment;

[00023] ? Figure 8 and Figure 8a illustrate respectively a side view and a longitudinal sectional view of the filter unit of Figure 7;

[00024] ? figures 9a and 9b are two perspective views of a pre-filter according to a preferred embodiment, included in the filter assembly solution of figure 7;

[00025] ? figure 10 ? a longitudinal sectional view of the pre-filter of figures 9a and 9b;

[00026] - figure 11 shows an enlarged microscopic view of a portion of a screen included in a pre-filter included in the filter unit in accordance with the present invention;

[00027] - figure 12 shows a schematization of a washing machine in accordance with the present invention. Detailed description

[00028] With reference to the attached figures, with the reference number 900 ? indicated a washing machine in accordance with the present invention. In addition, always with reference to the figures attached with the number 1 ? indicated a filter unit for a washing machine which is in turn the object of the present invention.

[00029] In accordance with the present invention, the washing machine 900 comprises a drum 910 in which the washing operations are performed. Note that the present invention is not limited to the type, shape, size, positioning, orientation, i.e. axis of rotation, mode? operational (for example the rotation speed and the centrifuge) of the basket.

[00030] In accordance with the present invention, the washing machine 900 comprises a discharge duct 950 fluidly connected to the drum 910 (or more generally to the drum housing) and fluidly connectable to a domestic or industrial discharge system for discharging the ?water used in the 910 drum.

[00031] In accordance with a preferred embodiment, the washing machine 900 comprises a drain pump assembly 960 positioned along the discharge duct 950 to discharge the water from the drum 910. In accordance with a preferred embodiment, said pump assembly discharge pump 960 operates under suction with respect to the basket 910. Preferably, the discharge pump unit 960 comprises an impeller 965 whose rotation controls the suction action.

[00032] Filter group 1 ? positioned along said discharge duct 950 dividing it into a first section 951 and a second section 952. The first section 951 is fluidically connected to the basket 910 and the second section 952 fluidly connectable to the discharge system. In the first section 951 does ?dirty? water flow? i.e. containing water, dissolved detergents, dirt and above all said synthetic microfibres and said natural fibers, while in the second section 952 flows ?filtered water? that is, cleaned from synthetic microfibers and natural fibers.

[00033] In accordance with the present invention, the filter group 1 ? suitable for filtering water from natural fibers and synthetic microfibres by performing a two-phase action.

[00034] The filter group 1 in fact comprises a pre-filter 10 and a main filter 20.

[00035] According to a preferred embodiment, the pre-filter 10 and the main filter 20 are positioned fluidically in series in the direction of flow of the water.

[00036] The presence of the pre-filter 10 and the main filter 20 entails a synergistic effect which allows the achievement of the object set for the present invention by performing an effective filtration of the waste water from the natural fibers and from the synthetic microfibres respectively generated from fabrics made at least partially in natural materials such as, for example, cotton, but also linen and wool and from fabrics made at least partially in synthetic material.

[00037] According to a preferred embodiment, the filter unit 1 performs two distinct actions in series aimed at cleaning the water discharged, first of all from the natural fibers and secondly from the synthetic microfibres. In particular, as extensively described below, the filter unit 1 object of the present invention exploits the different chemical nature of natural fibers and synthetic fibers to separate them from the water stream.

[00038] As mentioned, as a result of circulation through the pre-filter 10, the natural fibers dispersed in the water agglomerate, creating fiber aggregates, or a pulp which? retained on the dirty side of the pre-filter 10 not reaching the main filter 20.

[00039] Synthetic fibers dispersed in water behave differently from natural fibers. In fact, they do not tend to agglomerate. These fibers are transported by the water current crossing the pre-filter 10 and reach the main filter 20 where they are blocked and retained, and then filtered by the water current.

[00040] In accordance with a preferred embodiment, the pre-filter 10 separates the natural fibers referred to in natural fiber fabrics, for example cotton, linen or wool, from the water, while the main filter 20 filters and retains the synthetic microfibres referred to in synthetic fabrics.

[00041] In accordance with the present invention, the filter group 1 filters synthetic microfibres having a diameter greater than 1 micron and a length greater than 50 microns, preferably comprised between 50 microns and 5 mm.

[00042] In accordance with the present invention, the filter unit 1 is suitable for filtering synthetic microfibres of micrometric dimensions, ie having a diameter greater than 10 microns and a length greater than 50 microns, preferably between 50 microns and 5 mm.

[00043] In accordance with the present invention, the filter assembly 1 extends along the X-X axis.

[00044] In turn, in the modalities? described below, both the pre-filter 10 and the main filter 20 develop with respect to the X-X axis.

[00045] In fact, according to the present invention, both the pre-filter 10 and the main filter 20 develop around the X-X axis and perform the filtration operations in a radial direction.

[00046] In fact, the pre-filter 10 identifies a dirty pre-filter region 11 and a clean pre-filter region 12 radially separated.

[00047] Similarly, the main filter 20 in turn identifies a dirty filter region 21 and a clean filter region 22 radially separated. The pre-filter clean region 12 ? fluidly connected with the dirty filter region 21.

[00048] In accordance with the present invention, the pre-filter 10 comprises a micrometric mesh 100 which develops around the axis X-X, which can be crossed radially by the water.

[00049] Said micrometric mesh 100 ? a fabric composed of monofilament threads.

[00050] According to a preferred embodiment, said micrometric mesh 100 ? a fabric composed of monofilament threads woven according to a weave comprising weft monofilament threads and warp monofilament threads.

[00051] According to a preferred embodiment, each monofilament has a wire diameter Df of between 15 and 150 microns.

[00052] In accordance with a preferred embodiment, the monofilament yarns are woven so as to form a micrometric mesh having a thickness of between 0.003 and 1 mm. Monofilament threads can be woven into a single layer or a multilayer structure.

[00053] Preferably, in the reciprocal crossing between the monofilament threads, i.e. in the reciprocal crossing between the weft monofilament threads and the warp monofilament threads, mesh openings Ar are delimited.

[00054] Preferably, in the reciprocal crossing between the monofilament threads, net openings Ar of quadrangular shape, preferably of rectangular shape, are delimited.

[00055] Preferably, each Ar mesh opening defines a passage area between 2500 micron^2 and 250000 micron^2.

[00056] In accordance with a preferred embodiment, the micrometric mesh 100 comprises a passage section Sp comprised between 40% and 70% of the total surface of the micrometric mesh 100.

[00057] In other words, the passage section Sp ? the sum of all the transit areas, i.e. ? the sum of all Ar network openings.

[00058] Preferably, in the embodiment with square net openings Ar, each net opening Ar has an opening side Lr. Preferably, the value of the passage section Sp, as a percentage, ? calculated as follows:

[00059] In other words, the value of the passage section Sp ? the ratio between the passage surface available for the passage of water and the total surface of the micrometric mesh. In further other words, the passage section Sp ? therefore the ratio between the passage area defined by a mesh opening and the total surface of the micrometric mesh in correspondence with said mesh opening also considering the surface occupied by the wire.

[00060] It is emphasized that in the present discussion, the permeability values, described below with reference to the micrometric mesh 100 of the pre-filter 10 and to the non-woven fabric 200 of the main filter 20, are measured in accordance with the EN standard ISO 9237:1995 on a sample with an area equal to 20cm<2 > at 200 Pascal.

[00061] According to a preferred embodiment, the micrometric mesh 100 has permeability equal to or greater than 4000 l/(m<2>s).

[00062] According to a preferred embodiment, the micrometric mesh 100 has permeability between 4000 l/m<2 >s) and 17000 l/(m<2 >s).

[00063] According to a preferred embodiment, the micrometric mesh 100 has permeability including 8000 l/m<2 >s) and 11000 l/(m<2 >s).

[00064] According to a preferred embodiment, the monofilament threads of the micrometric mesh 100 are made of polymeric material.

[00065] According to a preferred embodiment, the monofilament threads of the micrometric mesh 100 are made of polyester, polybutylene terephthalate, polyamide, polypropylene or a combination thereof.

[00066] In accordance with the present invention, the filter unit 1 comprises a tubular-type filter media 200 which extends along a filter axis X-X.

[00067] In particular, does the filtering media 200 identify a cavity? filter 250.

[00068] The filter media 200 ? traversed radially by the flow of water.

[00069] In accordance with the present invention, the filter media 200 ? crossed radially from inside to outside: in other words, the cavity? filter 250 defines the ?dirty side? of the filter unit 1, (ie the dirty filter region 21) while the ?clean side? ? outside it (that is, the clean filter region 22 of the main filter 20 corresponds to the circulation region positioned outside the filter media 200).

[00070] In accordance with the present invention, the filter media 200 ? in a non-woven fabric suitable for filtering synthetic microfibers of micrometric dimensions. By synthetic microfibres of micrometric dimensions is meant fibers having a diameter greater than 1 micron, preferably 10 micron, and a length greater than 50 micron, preferably comprised between 50 micron and 5 mm.

[00071] In other words, the non-woven fabric has open tortuous passages through which the ?dirty? flows towards the downstream side of the filter media while the synthetic microfibers are blocked by means of the tortuosity? defined by the reciprocal interweaving of the synthetic fibers that make up the non-woven fabric of the filter media 200. In particular, due to their relatively high length, the synthetic microfibres remain trapped on the inlet surface of the non-woven fabric and/or in the tortuosity? of the non-woven fabric without being able to reach the outlet side of the filter and therefore reach the exhaust system.

[00072] According to a preferred embodiment, the filter media 200? obtained with a sheet of filtering material, preferably non-woven fabric, arranged in a star shape. Preferably, the star-shaped filter media 200 has a large filter surface, as well as a large filter surface. presents a series of spaces that can be occupied by microfibres (compared to tubular or panel filters of equal dimensions).

[00073] According to a preferred embodiment, the filter media 200? obtained with a sheet of filtering material, preferably non-woven fabric, wrapped in the shape of a tube or cylinder.

[00074] According to a preferred embodiment, the non-woven fabric is in synthetic fibers of PLA (polylactic acid).

[00075] In accordance with a preferred embodiment, the non-woven fabric is made of synthetic fibers made of polypropylene and/or polyester and/or polyamide or a combination thereof. Preferably, the non-woven fabric is in synthetic fibers of recycled polyamide. Preferably, the non-woven fabric is in single-component synthetic fibers. Preferably, the non-woven fabric is in two-component synthetic fibers. In accordance with a preferred embodiment, the non-woven fabric comprises a polypropylene-coated polyester core. In accordance with the above, and in accordance with what can also be deduced below, thanks to the random-type structure of the non-woven fabric, the filtering media 200 has high permeability? to water without limiting the filtering effectiveness: in fact, the filtering structure? extremely efficient, i.e. with a very permeable fibrous structure (with low pressure drop) at the same time while being able to capture synthetic microfibers of smaller diameter than the average diameter of the pores that make up the filtering material.

[00076] According to a preferred embodiment, the filter media 200 and in particular the sheet of non-woven fabric ? produced using spunbond, air laid, spun-laid or melt-blown methods. Thanks to these processing technologies, the synthetic fibers that make up the filtering media 200 are joined/welded, preferably mutually intertwined in a random manner, one to the other, creating a porous structure useful for the filtration of the polluting microfibers and at the same time capable of minimizing the release into the environment of the fibers of the filter media 200. According to a preferred embodiment, the filter media 200 and in particular the sheet of non-woven fabric ? produced through spun-bond with two-component synthetic fibers with polyester core (PET or PBT) and polypropylene (PP) coating. This combination makes it possible to give the synthetic fibers certain mechanical characteristics of bulk (useful, for example, for the workability of the media, in particular the foldability) and specific properties? surfaces useful for water filtration.

[00077] In accordance with a preferred embodiment, moreover, the filtering media 200 has a permeability value of equal to or greater than 1500 l/(m<2>s). In accordance with a preferred embodiment, moreover, the filtering media 200 has a permeability value of equal to or greater than 2000 l/(m<2>s). Preferably, the filter media 200 has a permeability value equal to or greater than 2900 l/(m<2>s). Preferably, the filter media 200 has a permeability value equal to or greater than 2500 l/(m<2>s). Preferably does the filter media 200 have permeability? between 2900 l/(m<2>s) and 4000 l/(m<2>s).

[00078] According to a preferred embodiment, the filter media 200 of the main filter 20 has a permeability bottom of the micrometric mesh 100 of the pre-filter 10.

[00079] According to a preferred embodiment, the relationship between the permeability? of the micrometric network 100 and the permeability? of non-woven fabric 200 ? less than 11.

[00080] Preferably, the relationship between the permeability? of the micrometric network 100 and the permeability? of non-woven fabric 200 ? less than 3.

[00081] According to a preferred embodiment, the main filter 20 has a greater filtering surface than the pre-filter 10. The greater available filtering surface of the non-woven fabric allows the use of a filter media with less permeability than the pre-filter 10. bottom, and take advantage of a main filtration stage capable of effectively filtering synthetic microfibers and accumulating an adequate quantity of fibers.

[00082] Preferably, the ratio between the filtering surface of the main filter 20 and the filtering surface of the pre-filter 10 ? greater than or equal to 5.

[00083] Preferably, the ratio between the filtering surface of the main filter 20 and the filtering surface of the pre-filter 10 ? greater than or equal to 10.

[00084] In accordance with a preferred embodiment, the main filter 20 comprises a main support structure 25 on which ? mounted the filter media 200.

[00085] Preferably, the main support structure 25 comprises two end plates 251, 252 arranged at the ends? axial of the filtering media 200, for example a first end plate? 251 and a second course at the end? 252. Preferably, the end plates? 251, 252 are welded at the ends? of the filter media 20.

[00086] In accordance with a preferred embodiment, the first end plate 251 is located fluidly upstream from the second end plate? 252. In other words, the first course at the end? 251 ? intercepted by the dirty water before the second course at the end? 252.

[00087] Preferably, depending on the direction of the flow, and on the various components also described below, the first end plate? 251 comprises a first through opening 2510. Preferably the second end plate? 252 ? closed. Preferably, the second end dish? 252, axially delimits the cavity? filter 250 included in the filter media 200. Preferably, the cavity? filter 250 ? reached by the water to be filtered through the through opening 2510.

[00088] According to a preferred embodiment, the first through opening 2510 is obtained on the first plate d? end? 252 in correspondence with the X-X filter axis.

[00089] In accordance with some variant embodiments, the main support structure 25 comprises an internal structure 255 which extends into the cavity? filter 250 and connects the two end plates? 251, 252.

[00090] Preferably, the internal structure 255 has a substantially reticular structure to allow the passage of the water flow in a radial direction.

[00091] In accordance with a preferred embodiment, said main support structure 25? in a plastic material, thus being recyclable.

[00092] According to a preferred embodiment, the pre-filter 10 ? positioned along the X-X axis axially adjacent to the main filter 20 and the micrometric mesh 100 ? traversable from outside to inside.

[00093] According to a preferred embodiment, the pre-filter 10 is in fluidic communication with the cavity? filter 250 defined by filter media 200.

[00094] In other words, the clean region 11 of the prefilter 10 ? in fluidic communication with the cavity? filter 250 defined by the filter media 200. According to a preferred embodiment, the pre-filter 10 comprises a support frame 150 suitable for supporting the micrometric mesh 100.

[00095] Preferably, said support frame 150 comprises a plurality of of longitudinal ribs 151 on which the micrometric mesh 100 rests. Preferably, said longitudinal ribs 151 are angularly spaced from each other.

[00096] In particular, the support frame 150 supports the micrometric mesh 100 in such a way as to present some passage windows 1500 through which the water passes through the micrometric mesh 100 and some impermeable portions 152 in which the transit of the water flow? prevented.

[00097] For example, the waterproof portions 152 extend between two longitudinal ribs 151, preventing the passage of water between two longitudinal ribs 151.

[00098] In accordance with a preferred embodiment, the support frame 150 provides a structural abutment to the micrometric mesh 100 in such a way as to prevent the action of water from breaking or bending it.

[00099] According to a preferred embodiment, the pre-filter 10 has a cylindrical, or tubular, or conical, or frusto-conical shape. That is, the pre-filter 10 extends parallel to the X-X axis or extends inclined to the X-X axis.

[000100] In accordance with a preferred embodiment, the support frame 150 is suitable for supporting the micrometric mesh 100 in such a way as to form a body with a hollow shape (cylindrical or tubular or conical or truncated cone).

[000101] In accordance with a preferred embodiment, the micrometric mesh 100 ? arranged parallel to the X-X axis, i.e. in a cylindrical shape. Preferably, the support frame 150 therefore has a substantially cylindrical arrangement and in turn the micrometric mesh 100 has a substantially cylindrical shape.

[000102] According to a preferred embodiment, the micrometric mesh 100 ? arranged inclined with respect to the X-X axis, i.e. in a truncated cone shape, tapered towards the main filter 20 or tapered in the opposite direction to the main filter 20. Preferably, the support frame 150 therefore has a substantially inclined arrangement so to identify inclined support walls for the micrometric mesh 100.

[000103] According to a preferred embodiment, the support frame 150 is formed in plastic material by moulding, preferably injection moulding.

[000104] Preferably, the micrometric mesh 100 ? integrated to the support frame 150 by overmoulding.

[000105] Alternatively, the micrometric mesh 100 ? fixed to the support frame 150 by welding, for example ultrasonic welding or infrared welding.

[000106] According to a preferred embodiment, the support frame 150 also comprises radial barriers 153 which extend in the radial direction forming a water obstacle.

[000107] Preferably, said radial barriers 153 extend radially beyond the micrometric mesh 100 in the dirty pre-filter region 11 and are such as to force and direct the motion of the water.

[000108] According to a preferred embodiment, the filter unit 1 comprises a filter body 3 comprising an inlet port 31 and an outlet port 32. Dirty water and water to be filtered from the washing machine drum 910 flows through the inlet port 31. The water filtered by the micrometric fibers flows towards the drain through the outlet mouth 32.

[000109] In accordance with a preferred embodiment, the inlet mouth 31 is positioned with respect to the X-X axis and with respect to the micrometric mesh 100 in such a way as to favor a flow of water in a tangential direction. That is to say that the entry of the water through the inlet mouth 31 is directed in such a way that it reaches the micrometric mesh 100 in a direction tangential to its development with respect to the X-X axis.

[000110] That is to say that inside the filter body 3, in a region which houses the pre-filter 10, the water has a spiral motion from the outside to the inside, crossing with a radial component from the outside to inside the micrometric mesh 100.

[000111] According to a preferred embodiment, the presence, position and shape of the impermeable portions 152 and/or of the passage windows 1500 and/or of the radial barriers 153 also favor said tangential motion of the water.

[000112] In accordance with a preferred embodiment, the filter body 3 comprises a first body 310 on which ? housed the pre-filter 10 and a second body 320 in which? the main filter 20 is housed, in which the second body 320 comprises the outlet mouth 32, in which the first body 310 and the second body 320 are fluidly connected to each other in a sealed manner.

[000113] According to a preferred embodiment, the inlet mouth 31 is positioned on the first body 310.

[000114] According to a preferred embodiment, the main body 3 comprises a recirculation mouth (not shown) suitable for recirculating the water being filtered from the filter unit 1 inside the basket 910.

[000115] According to a preferred embodiment, the main body 3 comprises a recirculation mouth in fluid communication with the clean filter region 22 and suitable for recirculating the water filtered by the filter unit 1 inside the drum 910.

[000116] According to a preferred embodiment, said recirculation mouth ? made on the second body 320.

[000117] Preferably, the pre-filter 10 ? which can be coupled to the main filter 20. The two filters are fixed to the first body 310 and subsequently the assembly made up of the first body 310, pre-filter 10 and main filter 20? engaged to the second corps 320.

[000118] In other words, the first body 310 ? suitable for supporting the pre-filter 10, the main filter 20 and for serving as a cover.

[000119] In accordance with a further preferred embodiment, the pre-filter 10? positioned along the X-X axis inside the main filter 20, in which the micrometric mesh 100 ? traversable from inside to outside.

[000120] In other words, the micrometric mesh 100 and the filtering media 200 are crossed by the water in the same radial direction.

[000121] In other words, the micrometric mesh 100 ? housed inside the cavity? filter 250.

[000122] According to a preferred embodiment, the pre-filter 10 comprises a support frame 150 suitable for supporting the micrometric mesh 100.

[000123] Preferably, said support frame 150 comprises a plurality of of longitudinal ribs 151 on which the micrometric mesh 100 rests. Preferably, said longitudinal ribs 151 are angularly spaced from each other.

[000124] In other words, the support frame 150 ? suitable for supporting the micrometric mesh 100 in such a way as to form a fluidically permeable hollow body (cylindrical or tubular or conical or frustoconical) delimiting respective water circulation zones in the dirty pre-filter region 11 and in the clean pre-filter region 12, mutually separated by the micrometric mesh 100.

[000125] In addition, the support frame 150 ? suitable for providing a structural abutment to the micrometric mesh 100 in such a way as to prevent the action of water from breaking or bending it.

[000126] In accordance with a preferred embodiment, the micrometric mesh 100 ? arranged parallel to the X-X axis, i.e. in a cylindrical shape. Preferably, the support frame 150 therefore has a substantially cylindrical arrangement and in turn the micrometric mesh 100 has a substantially cylindrical shape.

[000127] In particular, also in this embodiment, the support frame 150 supports the micrometric mesh 100 in such a way as to present some passage windows 1500 through which the water passes through the micrometric mesh 100 and some impermeable portions 152 in the what is the flow transit ? prevented.

[000128] For example, the waterproof portions 152 extend between two longitudinal ribs 151, preventing the passage of water between two longitudinal ribs 151.

[000129] According to a preferred embodiment, the impermeable portions 152 of the pre-filter are provided in the bottom region with the micrometric mesh. Preferably, the impermeable portions 152 close the end? of the cavity? circulation defined by the micrometric mesh in the dirty pre-filter 11 region of the pre-filter 10.

[000130] According to this embodiment in which the micrometric mesh 100 ? housed in the main filter 20, the pre-filter 10 comprises a conveyor structure 159 positioned along the X-X axis adjacent to the support structure 150. Preferably, said conveyor structure 159 conveys the incoming water towards the dirty pre-filter 11 region of the pre-filter 10.

[000131] In accordance with a preferred embodiment, the conveyor structure 159 conveys the incoming water inside a cavity pre-filter defined by the micrometric mesh 100 corresponding to the pre-filter 11 dirty region of the pre-filter 10. Preferably said pre-filter 11 cavity/dirty region of the pre-filter 10 is housed inside the cavity? filter 250.

[000132] According to a preferred embodiment, the conveyor structure 159 comprises walls and channel slides able to convey the water in a region proximal to the X-X axis to then start the filtration operations from inside to outside.

[000133] In accordance with this preferred embodiment, the filter unit 1 comprises a filter body 3 comprising an inlet port 31 and an outlet port 32. Preferably, the inlet port 31? radially facing said conveyor structure 159.

[000134] Furthermore, according to a preferred embodiment, the conveyor structure 159 seals the filter body 3 by capping it at one end thereof. axial.

[000135] In other words, in accordance with a preferred embodiment, the conveyor structure 159 is suitable to act both as a conveyor and as a closing lid.

[000136] According to a preferred embodiment, the conveyor structure 159 is operatively coupled to the pre-filter 10. Preferably, the conveyor structure 159 and the pre-filter 10 are integrated in a single component. Preferably, the conveyor structure 159 and pre-filter 10 are integrated in a single component also suitable for acting as a closing lid of the main body 3.

[000137] Preferably, the conveyor structure 159 and pre-filter 10 are integrally formed by molding, preferably injection molding.

[000138] Preferably, the conveyor structure 159 and the pre-filter 10 are operatively connected by mechanical coupling.

[000139] According to a preferred embodiment, the main body 3 comprises a recirculation mouth (not shown) suitable for recirculating the water being filtered from the filter unit 1 inside the basket 910.

[000140] According to a preferred embodiment, the main body 3 comprises a recirculation mouth in fluid communication with the clean filter region 22 and suitable for recirculating the water filtered by the filter unit 1 inside the drum 910.

[000141] According to a preferred embodiment, the filter unit 1 comprises a removable plug element 55 to allow access to the dirty side 11 of the micrometric mesh 100 in order to be able to carry out cleaning operations, in particular of the pre-filter 10.

[000142] In a preferred embodiment said cap element 55 also comprises a brush suitable for cleaning the entrance surface of the micrometric mesh 100.

[000143] According to a preferred embodiment, the pre-filter 10 and the main filter 20 do not affect the operation of the drain pump assembly 960. In particular, in accordance with a preferred embodiment, the drain pump assembly 960 ? of the type comprising a pump of the standard type, equipped with an impeller 965 whose rotation is? electrically controlled, preferably, with a maximum flow rate of 1000 l/h, suction head between 80 and 200 mbar.

[000144] In accordance with a preferred embodiment, the pre-filter 10 and the main filter 20 do not involve a pressure drop which causes a stall situation of the drain pump unit 960. In further other words, the presence of the il prefilter 10 and the main filter 20 do not require the need? to have a drain pump unit 960 with greater power than a washing machine solution such as those of the known art in which it is not? there is a filter unit 10 in accordance with what has been described above.

[000145] In accordance with a preferred embodiment, the drain pump assembly 960 is operatively coupled to the filter body 3, in an area proximal to the outlet mouth 32.

[000146] In accordance with a preferred embodiment, the drain pump unit 960 is positioned inside the filter body 3, in an area proximal to the outlet mouth 32.

[000147] According to a preferred embodiment, the washing machine 900 also comprises a pressure sensor unit 980 suitable for detecting the pressure of the water flow, preferably suitable for detecting the difference in water pressure between the inlet and the outlet of the filter unit 1.

[000148] In accordance with a preferred embodiment, the pressure sensor unit 980 detects the water pressure difference between the clean region and the dirty region of the filter unit 1.

[000149] In accordance with a preferred embodiment, the pressure sensor assembly 980 detects the water pressure difference between the clean region of the main filter 20 and the dirty region of the pre-filter 10. In other words, the pressure sensor assembly pressure 980 ? suitable for detecting the pressure drop due to the presence of the pre-filter 10 and the main filter 20.

[000150] According to a preferred embodiment, the washing machine 900 comprises a unit command that ? operatively connected with said pressure sensor unit 980, in such a way that the latter is suitable for sending a signal to said unit? command function of what was detected. For example:

- a filter pre-clogging signal, i.e. filter running out, with the pressure value detected (preferably pressure differential) higher than a first pre-set value and lower than a second pre-set value;

- an occluded filter signal, i.e. exhausted filter, with a detected pressure value (preferably pressure differential) higher than said second predetermined value;

- a clogged filter and washing machine stop signal, i.e. filter to be replaced, with pressure difference higher than said second pre-established value.

[000151] According to a preferred embodiment, the unit? command ? connected or corresponds to a control panel included in the washing machine 900. In this way the operator can? be warned about the maintenance status of the filter group 1 through the lighting of one or more? indicator lights or through a display of the washing machine 900.

[000152] Innovatively, the filter unit and the washing machine which comprises it, object of the present invention largely fulfill the object of the present invention by solving the problems which have emerged in the typical solutions of the state of the art.

[000153] Advantageously, the filter assembly effectively filters the waste water from the natural fibers and synthetic microfibres.

[000154] Advantageously, the presence of the pre-filter and the main filter and their synergistic action, also allows mixed washing of natural fiber garments, synthetic garments or mixed natural/synthetic garments to be possible, without affecting the useful life of the filter unit.

[000155] Advantageously, ? avoided the? eventuality? that the natural fibers clog the tortuosity? of the non-woven fabric of the main filter.

[000156] Advantageously, thanks to the micrometric mesh obtained with monofilament threads, the pre-filter has a permeable, smooth, compact surface which can be washed away by the incoming water flow and which does not retain the natural fibers as occurs with threads obtained by means of a plurality? of woven threads or with pre-filters made of fibrous materials in the form of non-woven fabric. Advantageously, the washout effect is favored by means of a micrometric mesh with monofilament threads arranged in a cylindrical or truncated cone shape, ie presenting surfaces which facilitate the circulation of the water flow in the inlet region to the filter assembly.

[000157] Advantageously, the natural fibers, not being fixed to the micrometric mesh, are subject to the motions of the water by populating the dirty region.

Advantageously, these movements do s? that the inlet surface of the micrometric mesh is washed away by the flow of water entering the filter unit, avoiding clogging of the micrometric openings of the mesh. Such movements do s? that the microfibers agglomerate going to accumulate in a region far from the inlet.

[000158] Advantageously, the entry of water in a tangential direction with respect to the micrometric mesh favors said advantageous phenomenon of agglomeration of natural fibres.

[000159] Advantageously, the truncated cone shape of some embodiments of the pre-filter favors said advantageous phenomenon of agglomeration of the natural fibres.

[000160] In fact, the synthetic microfibers produced in the washing operations of synthetic fabrics are advantageously retained and are therefore not discharged into the waste systems and therefore into the environment.

[000161] Advantageously, the filter unit and the washing machine, object of the present invention obviate the problem of environmental pollution by microplastics presenting themselves with a long life cycle.

[000162] Advantageously, the filter unit operates without affecting the operation of the other components of the washing machine such as the drum and above all the drain pump unit.

[000163] Advantageously, the filter assembly operates efficiently in filtration as long as it is not saturated with synthetic microfibres. Advantageously, the filter media intercepts and accumulates a specific quantity? of microfibres allowing the normal functioning of the drain function (without overloading the drain pump unit).

[000164] Advantageously, the filter group ? made of recyclable materials.

[000165] Advantageously, the maintenance and replacement operations of the filter assembly are simple and intuitive.

[000166] Advantageously, the filter group ? a simple component with contained costs and which allows to keep the structure of the washing machine relatively simple.

[000167] Advantageously, the pre-filter in the form of a micrometric mesh made up of a fabric of monofilament threads allows the natural fibers to be retained and accumulated in the region of the dirty side, avoiding early clogging of the main filter and undesired interruptions of the washing cycle.

[000168] Advantageously, the filter unit with fabric pre-filter and main filter in non-woven fabric allows the life of the filtering system to be extended before any maintenance operations are required.

[000169] Advantageously, the filter assembly with the main filter made of star-shaped non-woven fabric makes it possible to adequately exploit the available spaces, maximize the filtering surface of the main filter with respect to the surface of the micrometric mesh, thus minimizing the impact on the pressure drops imposed on the discharge circuit. Advantageously, the filter unit with a cylindrical pre-filter installed inside a main filter with a star-shaped non-woven fabric makes it possible to adequately exploit the available spaces to obtain a pre-filter washout effect, maximize the surface filtering of the main filter with respect to the surface of the micrometric mesh allowing the installation of the filter group on the washing machine without substantial modifications to the drain circuit.

[000170] Advantageously, the pre-filter ? made in the form of a cleanable, reusable filter, reducing the number of parts subject to periodic replacement and making the maintenance procedure more efficient. simple and cheap.

[000171] Advantageously, the pre-filter ? integrated on the cover of the main body resulting in a non-replaceable component. In this way the main filter remains the only component subject to periodic replacement, minimizing the consumption of plastic and therefore improving the environmental impact associated with the production of the washing machine and its use.

[000172] Advantageously, the pre-filter ? integrated on the cover of the main body, simplifying the production operations of the filter group and assembly of the assembly.

[000173] Advantageously, does the filter unit have permeability? such as not to affect the drainage time of the washing water towards the drainage system, ensuring the containment of electricity consumption associated with the functioning of the washing machine.

[000174] Advantageously, the synthetic microfibres are accumulated on the inner side of the filtering media, avoiding the release of synthetic microfibres into the environment during maintenance operations.

[000175] It is clear that a technician in the sector, in order to satisfy contingent needs, could make modifications to the invention, all contained in the scope of protection as defined by the following claims.

Reference number list:

[000176]

1 filter group

10 pre-filter

11 pre-filter dirty region

12 clean region pre-filter

100 micrometric mesh

150 support frame

1500 pass window

151 longitudinal ribs

152 waterproof portions

153 radial barrier

159 conveyor structure

20 main filter

21 region dirty filter

22 clean region filter

200 filter media

250 cavities? filter

25 main support structure

251 first course of? end?

2510 through opening

252 second course of? end?

255 internal structure

3 filter body

31 inlet

32 outlet mouth

310 first body

320 Second Corps

900 washing machine

910 basket

950 exhaust pipe 951 first section

952 second stretch

960 drain pump assembly 965 impeller

980 pressure sensor Df Wire diameter

Ar net openings

Lr opening side

Sp Passage section

X-X filter axis

Claims (20)

1. A filter assembly (1) for a washing machine (900), for filtering the water leaving a washing machine drum (910) towards the drain system, in which the filter assembly (1) extends along an axis ( X-X) including: - a pre-filter (10) comprising a micrometric mesh (100) which develops around the axis (X-X), which can be traversed radially by the water, in which the micrometric mesh (100) is? a fabric composed of monofilament threads; - a main filter (20), fluidly positioned downstream of the pre-filter (10), suitable for filtering synthetic microfibres of micrometric dimensions comprising a tubular filter media (200), defining a cavity; filter (250), which can be crossed radially by the water from inside to outside, in which the filtering media (200) is ? in a non-woven fabric, preferably made of synthetic fibers. 2. Filter unit (1) in accordance with claim 1, wherein each monofilament wire has a wire diameter (Df) comprised between 15 and 150 microns, the monofilament wires in their mutual intersection delimit net openings (Ar), preferably of quadrangular shape, defined by opening sides (Lr), in which each mesh opening (Ar) defines a passage area between 2500 micron^2 and 250000 micron^2. 3. Filter assembly (1) in accordance with claim 2, wherein the micrometric mesh (100) comprises a passage section (Sp), the sum of all the passage areas, comprised between 40% and 70% of the surface total micrometric mesh (100). 4. Filter unit (1) according to any one of the preceding claims, wherein the monofilament threads of the micrometric mesh (100) are made of polymeric material, preferably, of polyester, polybutylene terephthalate, polyamide, polypropylene or a combination thereof. 5. Filter assembly (1) according to any one of the preceding claims, wherein the filter media (200) is in a non-woven fabric of synthetic fibers in polypropylene and/or polyester and/or polyamide. 6. Filter unit (1) according to claim 5, wherein the synthetic fibers of the non-woven fabric are bi-component, comprising a polypropylene coated polyester core. 7. Filter unit (1) according to any one of the preceding claims, wherein the filtering media (200) filters synthetic microfibres of micrometric dimensions, having a diameter greater than 1 micron and a length greater than 50 microns. 8. Filter assembly (1) according to any one of the preceding claims, wherein the filter media (200) is obtained with a sheet of non-woven fabric arranged in a star shape. 9. Filter assembly (1) according to any one of the preceding claims, wherein the pre-filter (10) is? positioned along the axis (X-X) axially adjacent to the main filter (20), in which the micrometric mesh (100) is? passable from outside to inside, in which the pre-filter (10) ? in fluidic communication with the cavity? filter (250) defined by the filter media (200). The filter assembly (1) according to claim 9, wherein the pre-filter (10) comprises a support frame (150) adapted to support the micrometric mesh (100), wherein the pre-filter (10) extends parallel to the axis (X-X), i.e. in a cylindrical shape, or extends at an angle to the axis (X-X), i.e. in a truncated cone shape, tapered towards the main filter (20) or tapered away from the main filter (20) . 11. Filter unit (1) according to claim 10, wherein the support frame (150) comprises passage windows (1500) through which the water flows, through the micrometric mesh (100) and impermeable portions (152 ) in which the transit of the water flow? prevented. 12. Filter assembly (1) according to any one of claims 9 to 11, comprising a filter body (3) comprising an inlet port (31) and an outlet port (32), wherein the inlet port ( 31) ? positioned with respect to the axis (X-X) in such a way as to favor a flow of water in a tangential direction with respect to the micrometric mesh (100). 13. Filter assembly (1) according to claim 12, wherein the filter body (3) comprises a first body (310) on which? housed the pre-filter (10) and a second body (320) in which ? the main filter (20) is housed, in which the second body (320) comprises the outlet mouth (32), in which the first body (310) and the second body (320) are mutually engaged in a fluidly connected seal. 14. Filter assembly (1) in accordance with any one of claims from 1 to 8, wherein the pre-filter (10), preferably of a cylindrical shape, is positioned along the axis (X-X) in the cavity? filter (250) defined by the filter media (200), wherein the micrometric mesh (100) is traversable from inside to outside. The filter assembly (1) according to claim 14, wherein the pre-filter (10) comprises a support frame (150) adapted to support the micrometric mesh (100) and comprises a conveyor structure (159) positioned along the axis (X-X) adjacent to the support frame (150), in which the conveyor structure (159) conveys the incoming water inside the micrometric mesh (100). 16. Filter assembly (1) according to claim 15, comprising a filter body (3) comprising an inlet port (31) and an outlet port (32), wherein the inlet port (31) is? radially facing said conveyor structure (159). 17. Filter assembly (1) according to claim 12 or claim 16, comprising a removable cap element (55) to access the micrometric mesh (100) in order to be able to perform cleaning operations. 18. A washing machine (900) comprising a washing machine drum (910) and a drain duct (950) suitable for joining the washing machine drum (910) to a drain system and including a filter assembly (1) according to any of the claims 1 to 17, positioned along said discharge duct (950). The washing machine (900) according to claim 18, comprising a drain pump assembly (960) positioned along the drain conduit (950) for drawing water from the drum (910), wherein the drain pump assembly ( 960) ? positioned fluidically downstream of the filter unit (1), in which the filter media (200) has a permeability value? equal to or greater than 1500 l/(m<2>s), preferably equal to or greater than 2000 l/(m<2>s), preferably equal to or greater than 2900 l/(m<2>s), preferably equal to or higher than 2500 l/(m<2>s), preferably between 2900 l/(m<2>s) and 4000 l/(m<2>s). 20. Washing machine (900) according to any one of claims 18 to 19, further comprising a pressure sensor assembly (980) suitable for sensing the pressure of the water flow, preferably adapted for sensing the water pressure difference between the inlet and outlet of the filter group (1).