MICROPLASTIC FILTER FOR A WASHING MACHINE

Abstract

A microplastic filter (also referred herein as fluid filter) for a washing machine has a filter housing, a first filter screen, a second filter screen, an inlet opening 16, and an outlet opening. The inlet and outlet openings communicate with each other through the first filter screen to define a direction of fluid flow. The first filter chamber has a retentate outlet, is particularly easy to handle if the second filter screen is arranged in a cavity of the filter housing, the inlet and outlet openings communicate with each other through the second filter screen, and the retentate outlet is arranged on a side of the second filter screen that faces the fluid flow.

Claims

1. A fluid filter comprising: with a filter housing, a first filter screen, a second filter screen, an inlet opening, and an outlet opening, wherein: the filter housing encloses a cavity and has at least the inlet opening and the outlet opening, the first filter screen is arranged in the cavity, the first filter screen at least partially delimits a first filter chamber and the second filter screen at least partially delimits a second filter chamber, the inlet outlet openings communicate with each other through the first filter screen such that a fluid can flow from the inlet opening through the first filter screen to the outlet opening, thereby defining a direction of the fluid flow, the first filter chamber has a retentate outlet, the second filter screen is arranged in the cavity of the filter housing, the inlet outlet openings communicate with one another through the second filter screen and the retentate outlet is arranged on a side of the second filter screen that faces the fluid flow.

2. A fluid filter according to claim 1, wherein the filter housing has a maintenance opening that is closed with a maintenance cover, and wherein the second filter screen is fastened to the maintenance cover.

3. A fluid filter according to claim 1, wherein the first filter screen and the second filter screen are arranged parallel with respect to the direction of the fluid flow.

4. A fluid filter according to claim 1, wherein the first filter chamber and the second filter chamber are arranged in series with respect to a retentate flow.

5. A fluid filter according to claim 1, wherein at least a part of the second filter screen at least partially delimits a second filter chamber, wherein the second filter chamber has a corresponding second filter chamber inlet opening which is attached to a retentate outlet, whereby a retentate passage is formed from the first filter chamber into the second filter chamber.

6. A fluid filter according to claim 5, wherein the fluid filter comprises a closure for the second filter chamber inlet opening, the closure is movable between an open position and a closed position, the closure in the closed position closing at least a section of the second filter chamber at least in a retentate-tight manner.

7. A fluid filter according to claim 6, wherein the closure is biased into the closed position, when the maintenance cover is closed, the closure is transitioned into the open position by a connecting piece of the fluid filter, when the maintenance cover is opened, the connecting piece releases the path of the closure to transition the closure into the closed position.

8. A fluid filter according to claim 1, wherein the fluid filter has at least one movable compression means configured to be moveable from a neutral position into a compression position, the compression means deforming the second filter screen in the compression position and thereby compressing the second filter chamber and/or separating at least one section of the second filter chamber from at least one other section of the second filter chamber.

9. A fluid filter according to claim 6, wherein the fluid filter has at least one movable compression means configured to be moveable from a neutral position into a compression position, the compression means deforming the second filter screen in the compression position and thereby compressing the second filter chamber and/or separating at least one section of the second filter chamber from at least one other section of the second filter chamber, wherein the maintenance cover has a locking mechanism which at least inhibits opening of the maintenance cover, wherein the locking mechanism is in operative connection with the closure for the second filter chamber inlet opening and/or the compression means, and wherein a movement of the closure into the closed position and/or a movement of the compression means into the compression position releases the locking mechanism.

10. A fluid filter according to claim 1, further comprising an agitator mounted movably relative to the first filter screen.

11. A fluid filter according to claim 10, further comprising bristles attached to the agitator to point in a direction of the first filter screen, wherein at least some of the bristles bear against the first filter screen, and wherein paths of movements of the bristles are defined by trajectories.

12. A fluid filter according to claim 11, wherein at least a part of a fluid flow facing side of the second filter screen is arranged outside the trajectories of the bristles.

13. A fluid filter according to claim 11, wherein the bristles are made of plastic and have a fiber diameter d smaller than or equal to d.sub.max, wherein d.sub.max/mm?{0.14; 0.12; 0.1, 0.09; 0.08; 0.05}, and wherein d?5 ?m.

14. A fluid filter according to claim 1, wherein the first filter screen and/or the second filter screen comprises at least one mesh with a mesh width m.sub.1 or m.sub.2 wherein u?m.sub.i?o and u?U={20 ?m, 30 ?m, 40 ?m, 45 ?m, 50 ?m} and o?O={50 ?m, 55 ?m, 60 ?m, 70 ?m, 80 ?m, 90 ?m, 100 ?m} and i?{1, 2}.

15. A fluid filter according to claim 1, housed in a washing machine housing of a washing machine, wherein the washing machine housing comprises at least one washing water drain connection, at least one fluid basin with a pump sump and at least one pump.

16. A fluid filter according to claim 15, wherein Washing machine the inlet opening is connected to the pump sump in a fluid-tight manner, and/or the outlet opening is connected to a suction side of the pump in a fluid-tight manner, and/or the pump is connected fluid-tight to a waste water pipe on a discharge side of the pump, and/or the waste water pipe has an end facing away from the pump, said end forming a wash water drain connection, and/or the wash water drain connection is located above the pump sump.

17. A fluid filter according to claim 16, wherein there is a reservoir located between the fluid filter and the suction side of the pump, a reservoir volume corresponding at least to the volume of the waste water pipe, and/or there is at least one non-return valve connected to an outlet side of the first filter screen and/or the second filter screen, said at least one non-return valve configured to only allow a flow from the outlet side of the first filter screen and/or the second filter screen to the suction side of the pump.

18. A maintenance cover for a fluid filter according to claim 2, wherein: the maintenance cover includes the second filter screen, wherein at least a section of the second filter screen forms at least a section of the first filter chamber with the inlet opening; at least one fluid-tight wall is located at a distance from the second filter screen such as to surround the second filter screen with the inlet opening of the second filter screen remaining free; a closure of an opening of the second filter chamber is configured to be moveable between a closed position and an open position such as to close at least the inlet opening of the second filter screen in at least retentate-tight fashion in the closed position.

19. A maintenance cover according to claim 18, wherein the following conditions are satisfied: wherein there is a gap between at least one section of the wall and at least one section of the first filter screen, said wall having a corresponding outlet opening, further comprising an outlet valve affixed to the at least one fluid-tight wall, the outlet valve containing a valve means that is movable between a corresponding open position and a corresponding closed position, wherein the valve means is preloaded into said corresponding closed position, wherein the valve means has an abutment or is connected to said abutment, wherein the abutment is configured such that a force applied to the abutment moves the valve means from the corresponding closed position to the corresponding open position.

20. A combination of a first filter screen according to claim 1 and at least one brush with bristles configured to clean said first filter screen, wherein the bristles are made of plastic and have a fiber diameter d smaller than or equal to d.sub.max, wherein d.sub.max/mm?{0.14; 0.12; 0.1, 0.09; 0.08; 0.05} and wherein d?5 ?m, and/or the first filter screen comprises at least one filter mesh with a mesh size m.sub.1, wherein u?m.sub.1o, u?U, o?O and U={20 ?m, 30 ?m, 40 ?m, 45 ?m, 50 ?m} and O={50 ?m, 55 ?m, 60 ?m, 70 ?m, 80 ?m, 90 ?m, 100 ?m}, and/or the bristles have a free fiber length/such that a ratio d/l of the fiber diameter d of the bristles to the free fiber length I of the bristles is about $\frac{1}{20}\mathrm{to}\frac{1}{200}.$

21. A combination according to claim 20, wherein the combination is a part of a fluid filter according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the following, the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment and with reference to the drawings.

[0033] FIG. 1 shows a first example of the fluid filter.

[0034] FIG. 2 shows a second example of the fluid filter.

[0035] FIG. 3 shows a third example of the fluid filter.

[0036] FIG. 4 shows a fourth example of the fluid filter.

[0037] FIG. 5 shows a maintenance cover for the fluid filter.

[0038] FIG. 6 shows a fourth example of the fluid filter.

[0039] FIG. 7 shows a maintenance hatch with a filter screen.

[0040] Generally, the drawings are not to scale. Like elements and components are referred to by like labels and numerals. For the simplicity of illustrations, not all elements and components depicted and labeled in one drawing are necessarily labels in another drawing even if these elements and components appear in such other drawing.

[0041] While various modifications and alternative forms, of implementation of the idea of the invention are within the scope of the invention, specific embodiments thereof are shown by way of example in the drawings and are described below in detail. It should be understood, however, that the drawings and related detailed description are not intended to limit the implementation of the idea of the invention to the particular form disclosed in this application, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION

[0042] FIG. 1 shows a fluid filter 1 with a filter housing 10. The filter housing 10 includes a maintenance opening, which in FIG. 1 is closed by a maintenance cover 11. The closure may preferably be fluid-tight or configured to be substantially fluid impenetrable. This can be achieved, for example, by a seal, a labyrinth seal or the like clamped between the maintenance cover 11 and an edge of the filter housing 10 bounding the maintenance opening. Like in FIG. 1, the maintenance cover may be attached to the edge of the housing and fixed in place by a friction fit. Alternatively, however, other connection techniques can also be used, such as a threaded connection, bayonet lock, snap-in lock, swivel connection, . . . , i.e. all these examples can be replaced by any other, preferably detachable fastening technique.

[0043] The filter housing 10 may include an inlet opening 16 and an outlet opening 17. The inlet opening 16 can, for example, be connected via a line to a pump sump or the pressure side of a pump of a washing machine or another machine. The outlet opening 17 can, for example, be connected to the suction side of a pump for pumping out a fluid. Both, the inlet opening 16 and the outlet opening 17 allow access to a cavity 15 enclosed by the filter housing 10. A first filter screen 21 and a second filter screen 22 are preferably arranged in the cavity 15 of the filter housing. The first filter screen 21 may delimit a first filter chamber 25, which communicates with the inlet opening 16. As in the example shown, the first filter screen 21 may be barrel-shaped and the first filter chamber 25 may correspondingly be at least approximately a circular cylinder with a longitudinal axis 2. However, other geometries of the first filter chamber are also possible. In order to keep the figure clearer, only the cut surface of the filter screens 21, 22 is shown (applies to all figures); the interior view of the two filter screens actually shown in the sectional drawings has been omitted, because the other details would hardly be recognizable against the grid background.

[0044] On the side facing away from the inlet opening 16, the first filter chamber 25 may include a retentate outlet. Like in the example shown, the retentate outlet may be the passage opening of a sealing ring 23, which may at the same time form the inlet opening of a second filter chamber 26. The second filter chamber 26 may be bounded by the second filter screen 22, similar to the way in which the first filter chamber 25 may be bounded by the first filter screen 21. The first filter screen 21 and the second filter screen 22 may be connected by a seal 23 (e.g. by said sealing ring 23) to form a filter element 20. A wall, e.g. that of the housing cover 11, preferably delimits the second filter chamber 26 on the side opposite the inlet opening 23 of the second filter chamber 26. Alternatively, the second filter chamber 26 can also be delimited by a separate base and/or the second filter screen 22 instead of the wall. The second filter screen can, for example, form a filter basket.

[0045] Preferably, the fluid filter 1 includes an agitator 30. Particularly preferably, the agitator 30 includes an agitator shaft 31, to which bristles 34 may be attached. The free ends of the bristles 34 may sweep over the side of the first filter screen 21 facing the first filter chamber 25 when the agitator 30 moves. For this purpose, the agitator can, for example, have webs 32, to the radial end of which at least one bristle holder 33 may be attached. The bristles 34 may be attached to the bristle holder 33 on the side of the bristle holder 33 facing the first filter screen 21. If the agitator shaft 31 may set in rotation by an optional drive 80, then the bristle holders 33 may be entrained via the webs 32, so that the bristles 34 sweep over the side of the first filter screen 21 facing the first filter chamber and thereby clean off retentate adhering to the first filter screen 21, e.g. microplastic particles. As in the example shown, the bristles 34 preferably do not sweep over the second filter screen 22, or at least not completely. As a result, during operation of the fluid filter 1, retentate accumulates in the second filter chamber on the side of the second filter screen 22 facing the second filter chamber 26.

[0046] The retentate can be transported on the one hand by the fluid flow from the inlet opening 16 to the outlet opening 17 and/or by the agitator 30. For example, the bristle holders 33 can be arranged in a spiral or spiral segment shape, so that the agitator resembles a screw conveyor. At this point, it should be noted that two bristle holders 33 are shown in the drawing, but that this number is merely exemplary and is to be understood in the sense of at least one bristle holder.

[0047] During operation, a fluid to be filtered, e.g. washing water to be filtered from a washing machine or another machine, may be fed into the first filter chamber 25 via the inlet opening 16 and also into the second filter chamber 26 through the retentate outlet opening. Part of the fluid flows through the first filter screen 21 and the second filter screen 22 and may be drawn off at the outlet opening 17. Impurities carried along by the fluid may be retained by and may hence remain on both the first filter screen 21 and the second filter screen 22.

[0048] The impurities deposited on the first filter screen 21 are cleaned off by the bristles 34 of the agitator 30, so that the first filter screen 21 is kept free. Retentate cleaned by the bristles 34 passes through the flow and preferably through the agitator 30 into the second filter chamber 26, where it may again be separated, but this time on the second filter screen 22. The cleaned fluid, i.e. the filtrate, can leave the fluid filter 1 through the outlet opening 17. Preferably, before the second filter chamber 26 is completely filled with retentate, the fluid flow through the inlet may preferably be stopped at least briefly, with any remaining fluid residues preferably being drawn off through the outlet opening 17. The maintenance cover 11 can now be opened and the retentate can be removed from the second filter chamber. In a preferred embodiment, as shown, the second filter screen may be firmly connected to the maintenance cover 11, so that when the maintenance cover is opened, retentate collected in the second filter chamber 26 can be removed together with the second filter screen. This unit can then be disposed of in accordance with local regulations and replaced by a new maintenance cover 11 with filter screen 22 attached to it.

[0049] FIG. 2 shows a further fluid filter 1 which is largely similar to the fluid filter 1 according to FIG. 1, so that the description of FIG. 1 can be read in its entirety to FIG. 2. In addition, the fluid filter 1 in FIG. 2 includes an optional compression means 40 with which retentate accumulated in the second filter chamber 26 can be compressed. As a result, on the one hand, the maintenance intervals of the fluid filter can be extended and, on the other hand, the retentate in the second filter chamber 26 can be compressed with the compression means 40, so that fluid still contained therein drains through the filter element 20, whereby undesired dripping of fluid from the maintenance cover 11 or from the second filter chamber 26 can be prevented or at least reduced. The compression means 40 preferably includes a grid 41 which, as indicated by the double arrow, can be moved parallel to the wall of the second filter screen. As in the example shown, the grid may be located at the free end of a piston rod of the agitator 30. It should also be mentioned that the mesh width of the grid 41 may be larger than the screen width of the filter element 20, so that cleaned retentate can be transferred through the meshes of the grid 41 into the second filter chamber 26.

[0050] FIG. 3 shows another fluid filter 1 and the description of FIG. 1 can again be read (almost) in full for the fluid filter 1 in FIG. 3. Only the differences are explained to avoid repetition. The fluid filter in FIG. 3 differs from the fluid filter in FIG. 1 only in that the first filter chamber and the second filter chamber are not arranged coaxially, but at an angle to each other. As a result, the retentate collects at the bottom of the second filter chamber 26, at least also due to gravity.

[0051] FIG. 4 shows a further fluid filter in longitudinal section along the longitudinal axis 2. The description of FIG. 1 can also be read (almost) completely onto FIG. 4, so that only the differences between the two fluid filters 1 are discussed below. In FIG. 4, the first filter screen 21 tapers on the side facing away from the inlet opening 16 in a section 27 referred to as taper 27 to form a nozzle, the open end of which forms the retentate outlet 29. The connecting piece 28 with the retentate outlet may project into the second filter chamber 26 through a seal 23 which may lie at least largely sealingly against the outside of the connecting piece 28. The seal 23 may delimit the second filter chamber 26 on the inlet side. The seal 23 can (other than shown) be attached to the second filter screen 22, for example. Like in the example shown, the seal 23 may be attached to the maintenance cover 11. For example, the seal 23 can be a sealing membrane that may be attached to an inlet-side section of an optional annular web 42. Inlet side here refers to the inlet of the second filter chamber 26, wherein the inlet is the opening of the second filter chamber 26 facing the inlet 16 of the filter housing 10 (with respect to the flow direction). As in the example shown, the seal 23 may span the second filter chamber on the inlet side. At least the optional section of the seal 23 between the second filter screen 22 and the optional annular web 42 of the maintenance cover 11 can be designed as a rigid wall. At least the section of the seal 23 through which the connecting piece 28 protrudes or in which it engages may preferably be made of an elastic material, e.g. a rubber-elastic material.

[0052] The optional annular web 42 can, for example, enclose the second filter screen and the second filter chamber 26 together with the base of the maintenance cover 11, as shown in FIG. 4. In order to improve the drainage of the filtrate, the annular web 42 can preferably have at least one drip opening 47 in its area facing the inlet.

[0053] If the maintenance cover in FIG. 4 is removed, the base of the maintenance cover 11 with its annular web 42 may form a basin that prevents unwanted dripping of residual fluid from the second filter chamber. Any filtrate escaping from optional drip openings 47 can, for example, be retained by an optional edge web 117 (see FIG. 5), which can, for example, have a thread or a joint 48 (see, for example, FIG. 7) for connecting the maintenance cover 11 to a base body of the filter housing 10.

[0054] Optional elastic flaps 231 on the seal 23 can, as shown in FIGS. 5 to 7, at least largely close the inlet to the second filter chamber, i.e. they may form a closure 231 of the inlet to the second filter chamber, which greatly simplifies a clean replacement of the second filter screen. When the second filter screen 22 is inserted into the housing, the connecting piece 28 acts as an opening device for the closed inlet of the second filter chamber 26. In addition, the optional flaps 231 can prevent improper emptying of the filter, for example by washing it out. The elastic flaps 231 serve here as an example of a closure of the inlet opening that may preferably be biased into its closed position, similar to a duckbill valve. Alternatively, the closure can be designed as a duckbill valve. As a further alternative, the closure can have at least one closure flap or the like, e.g. hinged, which may preferably be movable into the second filter chamber. Particularly preferably, the closure flap may be biased in the direction of its closed position when in the open position.

[0055] As shown in FIG. 6, the second filter screen 22 can also be detachably connected to the maintenance cover 11, so that correspondingly less waste is produced. For this purpose, the second filter chamber may be delimited by a base 13, which can be inserted into a receptacle in the maintenance cover 13. A snap-in connection between the base 13 and the maintenance cover 11 may be preferred, but other fastenings are also possible, such as bayonet, screw thread, etc. p. The optional base 13 can also be part of the second filter screen 22. The optional base 13 can also be provided in the embodiments of FIGS. 1 to 5. Incidentally, the description of FIGS. 4 and 5 can also be read with reference to FIG. 6.

[0056] FIG. 7 is largely identical to FIG. 6 and differs only in that the maintenance cover 11 is not fastened to the base body with a screw connection, but with a joint 48. Incidentally, the description of FIG. 6 can also be read onto FIG. 7.

[0057] It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide a fluid filter. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.

LIST OF REFERENCE NUMERALS

[0058] 1 fluid filter [0059] 2 longitudinal axis [0060] 10 filter housing [0061] 11 housing cover/maintenance flap/maintenance cover [0062] 117 edge web [0063] 12 housing web [0064] 13 base/floor [0065] 15 cavity [0066] 16 inlet opening/inlet [0067] 17 outlet opening/outlet [0068] 20 filter insert [0069] 21 first filter screen [0070] 22 second filter screen [0071] 23 seal/inlet opening of second filter chamber [0072] 231 closure/elastic flaps [0073] 25 first filter chamber [0074] 26 second filter chamber [0075] 27 tapered section/taper [0076] 28 connecting piece/opening device [0077] 29 retentate outlet [0078] 30 agitator [0079] 31 shaft [0080] 32 webs [0081] 33 brush holder [0082] 34 bristles [0083] 40 compression means [0084] 41 grid [0085] 42 ring/ring shaped web [0086] 47 drip opening [0087] 48 Joint [0088] 80 drive/motor