EP2325378A1

EP2325378A1 - Washing machine with improved filter for the draining circuit

Info

Publication number: EP2325378A1
Application number: EP09176718A
Authority: EP
Inventors: Danny Buso; Mirko Gasparini; Valter Lazzer
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2009-11-23
Filing date: 2009-11-23
Publication date: 2011-05-25
Also published as: CN102071559A; CN102071559B

Abstract

Washing machine (1) comprising:
- a washing tub (5);
- a draining sump (9) fluidly communicating to the internal of the washing tub (5) and fluidly connected to a draining circuit (10);
- a filter (12), associated or associable to the draining sump (9) and provided with a filtering surface (19) adapted for allowing the passage of a liquid and for impeding the passage of bodies of fixed dimensions.

The filter (12) comprises at least one by-pass conduit (21) adapted for directing a flow of washing liquid from the washing tub (5) to the bottom of the draining sump (9), by-passing the filtering surface (19).

Description

The present invention relates to a laundry washing machine with an improved filter for the draining circuit.
It is underlined that in the present application the expression "washing machine" may as well indicate a "simple" washing machine (i.e. a washing machine which can only wash and rinse the laundry) and a washing-drying machine (i.e. a washing machine which can also dry the laundry).
Moreover, even if in the following the present invention will be described, purely by way of example, in relation to a front-loading laundry washing machine, it is clear that the present invention may be applied, substantially without any crucial modification, to a top-loading washing machine.
Nowadays washing machines generally comprise an external casing provided with a loading/unloading door which allows the access to a washing tub containing a rotatable perforated drum in which the laundry to be washed can be loaded.
Known washing machines comprise a water inlet circuit adapted for feeding water and washing/rinsing products (i.e. detergent, softener, etc.) into the tub.
Known washing machines also comprise a water outlet circuit, typically comprising a drain pump and some draining pipes, adapted for draining the washing/rinsing liquid (i.e. water and water mixed with washing and/or rinsing products) from the tub after the washing and rinsing phases.
The water outlet circuit usually comprises a filtering device, placed between the bottom of the tub and the drain pump, adapted to retain all undesirable bodies (for example buttons came off from the laundry, coins erroneously introduced into the washing machine, etc.) passed through the holes located on the periphery of the drum, or fell to the bottom of the tub by passing between the drum and the tub, which could damage or obstruct the drain pump.
The most common of these filtering devices consists of a cylindrical box attached to the base of the washing machine and containing a removable filter fluidly connected upstream of the drain pump. This box containing the filter is accessible through a quick-removable plug that allows the filter to be removed and cleaned, the plug being hidden by a gate located, depending on the case, on the front or back wall of the external casing of the washing machine.
There are also known washing machines comprising a draining sump, obtained on the lower region of the lateral surface of the tub (i.e. in the bottom of the tub), fluidly communicating with the internal of the latter and fluidly connected upstream of the drain pump.
A filter is placed in the draining sump for retaining all undesirable bodies which may be contained in the washing/rinsing liquid, so as to avoid that such bodies could reach the draining pump; this filter is typically a cup-shaped body provided with a filtering surface, i.e. a surface provided with a plurality of apertures which are dimensioned in order to allow the passage of the washing/rinsing liquid, but to impede the passage of foreign bodies of prefixed dimensions.
In this case the rotatable drum of the washing machine is provided with at least one opening, closed by a removable lid, adapted for allowing a user to reach the filter from the internal of the washing machine, for example for cleaning such filter; typically the filter may be removed from the sump, so as to facilitate its cleaning.
A prior art washing machine containing a filter used to prevent residual particles of dirt from reaching and obstructing the pump and its drainage duct, and which can be removed from the internal of the tub, for inspection, cleaning and replacement, is illustrated, for example, in GB 1197919 , which discloses a washing machine comprising a tank (i.e. a tub) for liquid with an opening in its base, a draining pump connected by a pipe to the opening of the tank, and a basket (i.e. a rotary drum) disposed within the tank; a cup-like filter element having filter openings in its side wall is removably seated in the tank opening, and an opening is provided in the basket, provided with a removable closure, to provide access to the filter element.
Another example of known washing machine provided with a filter which can be removed from the internal of the tub is illustrated in FR 2190966 , which discloses a top-loading washing machine comprising a tub containing a rotary drum provided, on its lateral surface, with a first door, adapted for loading/unloading the laundry, and with a second door, disposed opposite to the first door and adapted for allowing the recovering of linen which would have slipped between the tank and the drum. A connector is fixed to the bottom of the tub, such connector being provided, at his inferior region, with a duct adapted to receive one of the extremities of a discharging pipe. A housing is provided in the connector, adapted to receive a filter accessible by simultaneously opening the two doors of the drum.
A further known washing machine comprising a filter accessible from the internal of the tub is illustrated in the European patent n. EP 1849904 , which discloses a top-loading washing machine comprising a draining filter access apparatus integrated in a lifter diametrically opposite to the drum access door (i.e. to the internal lid allowing the access to the drum). The draining filter access apparatus comprises a body, including an opening aligned with an opening of the same shape and dimensions made in the body of the drum, and a lid, hinged to the body and locking on the body by a simple ratchet mechanism.
The above mentioned known washing machines provided with a sump in the bottom of the tub and with a filter placed in the sump for retaining all undesirable bodies which may be contained in the washing/rinsing liquid, have however a drawback, which will be explained at once; at the beginning of the washing cycle the detergent is typically admitted into the tub by a flow of cold water, and then the water starts being heated and the drum starts rotating; the increasing of the water temperature, and mainly the mechanical agitation due to the rotation of the drum, favour the dissolving of the detergent in the washing water. The problem with the known solutions is that sometimes the detergent, flown into the tub by the cold water, enters in the draining sump before dissolving in the water, and tends to accumulate in the bottom of the draining sump, where the effect of the mechanical agitation of the water is almost nullified by the shape of the sump and by the presence of the filter which reduces the velocity of the water flux traversing it.
Therefore a certain amount of detergent remains in the bottom of the sump without dissolving in the washing water, reducing the overall washing efficiency.
Since part of the detergent doesn't dissolve in the washing water, the actual amount of detergent required for obtaining a certain washing effect is higher than the amount which would be sufficient if all the detergent would dissolve, and therefore there is a waste of detergent.
Moreover the detergent which accumulates in the bottom of the draining sump may sometimes obstruct the passage for the washing/rinsing liquid, with the subsequent problems of possible flooding of the washing machine that this may create.
The aim of the present invention is therefore ensuring that substantially all the washing/rinsing products (i.e. detergent, softener, etc.) admitted into the washing tub of a washing machine dissolves in the washing water, so as to efficiently employ substantially all the amount of washing/rinsing products which is admitted in the washing tub in a washing cycle.
Within this aim, another object of the invention is avoiding that the washing/rinsing products would accumulate in the bottom of the washing sump obstructing the flow of the washing liquid towasrds the draining circuit.
Another object of the invention is to be applicable also to a known washing machine with only few modifications of the latter.
It is therefore an object of the present invention to solve the above-noted problems, thereby doing away with the drawbacks of the cited prior art.
The Applicant has found that by using a filter for the draining circuit of a washing machine comprising at least one by-pass conduit which by-passes the filtering surface of the filter, and which is adapted for directing a flow of washing liquid from the washing tub to the bottom of a draining sump which connects the washing tub with the draining circuit, and to which the filter is associated or associable, it is possible to sweep away the washing/rinsing products accumulated in the bottom of the draining sump, favouring the melting of these products in the washing water and the re-admission of the water containing these melted products in the washing tub.
In particular, the above-mentioned aim and objects, as well as others that will become better apparent hereinafter, are achieved by washing machine comprising:

a washing tub;
a draining sump fluidly communicating to the internal of the washing tub and fluidly connected to a draining circuit;
a filter, associated or associable to the draining sump and provided with a filtering surface adapted for allowing the passage of a liquid and for impeding the passage of bodies of fixed dimensions.

The filter comprises at least one by-pass conduit adapted for directing a flow of washing liquid from the washing tub to the bottom of the draining sump, by-passing the filtering surface.
Preferably the by-pass conduit comprises a conduit adapted for fluidly connecting the internal of the washing tub with the bottom of the draining sump, and which has an imperforate lateral surface, so that substantially all the washing liquid entering the conduit in the washing tub is flown into the draining sump.
Opportunely the shape and the dimensions the at least one by-pass conduit are adapted for allowing the passage of liquid and for avoiding the passage of foreign bodies of prefixed dimensions.
Advantageously the shape and the dimensions of the at least one by-pass conduit are such that if a foreign body can't pass through the filtering surface it can't neither pass through the by-pass conduit.
Preferably the at least one by-pass conduit is dimensioned in such a way that the speed of a liquid exiting the at least one by-pass conduit is higher than the speed of a liquid entering the at least one by-pass conduit.
Advantageously the cross-section of the outlet of the at least one by-pass conduit is smaller than the cross-section of the inlet of the by-pass conduit, so that the speed of the flux of liquid exiting the by-pass conduit is higher than the speed of the flux of liquid entering the by-pass conduit.
Preferably the inlet of the at least one by-pass conduit is positioned, when the filter is positioned in the draining sump, above the bottom of the washing tub, so as to be stricken by the flux of water moved by the rotatable drum during its rotation.
Opportunely the filter is removable from the draining sump.
The filter may advantageously comprise a coupling device adapted for fixing it in a removable way to the draining sump.
Preferably the filter comprises a grasping element adapted for allowing a user to easily remove the filter form the draining sump.
In a further aspect the invention comprises a filter for the draining circuit of a washing machine, comprising a filtering surface adapted for allowing the passage of a liquid and for impeding the passage of bodies of fixed dimensions; the filter comprises at least one by-pass conduit adapted for directing a flow of liquid from one side of the filtering surface to the other side of the filtering surface, by-passing the filtering surface.
Advantageously the shape and the dimensions of the at least one by-pass conduit are adapted for allowing the passage of liquid and for avoiding the passage of foreign bodies of prefixed dimensions.
Opportunely the shape and the dimensions of the at least one by-pass conduit are such that if a foreign body can't pass through the filtering surface it can't neither pass through the by-pass conduit.
Preferably the at least one by-pass conduit is dimensioned in such a way that the speed of a liquid exiting the at least one by-pass conduit is higher than the speed of a liquid entering the at least one by-pass conduit.
Opportunely the cross section of the outlet of the at least one by-pass conduit is smaller than the cross section of the inlet of the by-pass conduit, so that the speed of the flux of liquid exiting the by-pass conduit is higher than the speed of the flux of liquid entering the by-pass conduit.
Features and advantages of the present invention will anyway be more readily understood from the description that is given below by way of non-limiting example with reference to the accompanying drawings, in which:

Figure 1 is a schematic, lateral and partially sectioned view, of a washing machine according to the invention;
Figure 2 is an isometric view, with parts in section and parts removed for clarity, of the washing tub of a washing machine according to the invention;
Figure 3 is an enlarged particular of Figure 2;
Figure 4 is a sectional lateral view of the washing tub of Figure 2;
Figure 5 is an enlarged particular of Figure 4;
Figure 6 is sectional frontal view of the washing tub of Figure 2;
Figure 7 is an enlarged particular of Figure 6;
Figure 8 is a sectional lateral exploded view of the filter of the washing machine of Figure 2;
Figure 9 is a sectional lateral view of the filter of Figure 8;
Figure 10 is a exploded prospective view of the filter of Figures 8 and 9;
Figures 11 and 12 are two prospective views of a further embodiment of a filter of a washing machine according to the invention;
Figure 13 is a lateral view of the filter of Figures 11 and 12;
Figure 14 is a lateral view of the filter of Figure 13 sectioned along plane XIV-XIV of Figure 13;
Figures 15 and 16 are a prospective and a sectional lateral view of a further embodiment of a filter of a washing machine according to the invention;
Figures 17 and 18 are a prospective and a sectional lateral view of a further embodiment of a filter of a washing machine according to the invention;
Figures 19 and 20 are a prospective and a sectional lateral view of a further embodiment of a filter of a washing machine according to the invention;
Figures 21 and 22 are two prospective views of a further embodiment of a filter of a washing machine according to the invention;
Figure 23 is a lateral view of the filter of Figures 21 and 22;
Figure 24 is a lateral view of the filter of Figure 23 sectioned along plane XXIV-XXIV of Figure 23.

The washing machine 1 according to the invention which is illustrated in the enclosed Figures is advantageously of the front-loading type; it is however clear that the invention is applicable, substantially without any crucial modification, to a top-loading washing machine.
It is also clear that the invention can be applied, substantially without any modification, both to a "simple" washing machine (i.e. a washing machine which can only wash and rinse the laundry) and to a washing-drying machine (i.e. a washing machine which can also dry the laundry).
With reference to the enclosed Figures, the washing machine 1 according to the invention, schematically represented in Figure 1, comprises an external casing 2 in which frontal wall 2a an access opening 3 is obtained, provided with a loading/unloading door 4, which allows the access to a washing tub 5 contained in the external casing 2; the washing tub 5 contains a rotatable perforated drum 6 in which the laundry to be washed, not illustrated, can be loaded (in the enclosed Figures, the holes obtained in the lateral surface of the rotatable perforated drum 6 have not been represented).
The washing tub 5 is connected the external casing 2 preferably via a flexible bellows 7, connected between the frontal, opened, surface of the washing tub 5 facing the access opening 3, and the border of the latter.
The washing machine 1 comprises a water inlet circuit 8 adapted to feed water and washing/rinsing products (i.e. detergents, softeners, etc.) into the washing tub 5; the water inlet circuit 8 advantageously comprises a removable drawer 8a, adapted to be filled with washing and/or rinsing products, for example detersives, softener, bleaching substances, etc.
The water inlet circuit 8 comprises also an inlet duct 8b, connectable to water delivery mains present outside the washing machine 1, and adapted to deliver fresh water to the drawer 8a; the water inlet circuit 8 comprises also an outlet duct 8c, fluidly connecting the drawer 8a and the tub 5 and adapted to deliver water and washing/rinsing products into the washing tub 5. Advantageously the water inlet circuit 8 comprises also one or more valves, not represented, adapted to regulate the flow of water.
When fresh water is admitted into the drawer 8a via the inlet duct 8b, such fresh water washes away the washing/rinsing products contained in the drawer 8a, and delivers these products into the washing tub 5 via the outlet duct 8c.
In another embodiment, not illustrated, the water inlet circuit 8 comprises one or more reservoirs for one or more washing/rinsing products from which a certain amount of these washing/rinsing products, depending on the washing program, is automatically delivered to the washing tub 5.
The washing machine 1 comprises a draining sump 9, obtained preferably on the lateral surface 5a of the tub 5, fluidly communicating with the internal of the tub 5, and fluidly connected to a draining circuit 10 adapted to drain the washing/rinsing liquid (i.e. water and water mixed with washing and/or rinsing products) from the tub 5.
Advantageously the draining sump 9 is placed in the lower region of the washing tub 5, so that the liquid contained in the latter can be conveyed by gravity towards this draining sump 9, and therefore to the draining circuit 10.
Preferably the draining sump 9 is obtained in a single-piece construction with the lower region of the tub 5, advantageously by moulding of a plastic material.
The draining circuit 10 comprises a draining pump 11 provided with an impeller, not illustrated, housed in an impeller chamber 11 a which is preferably, but not necessarily, obtained in a single-piece construction with the draining sump 9 and with the washing tub 5, preferably in correspondence to an extension of the draining sump 9.
In a further embodiment, not illustrated, the draining circuit 10 can be also provided with a recirculation circuit, adapted to drain the washing/rinsing liquid from the bottom of the tub 5, and to re-admit such liquid into an upper region of the tub, for improving the wetting of the laundry. The recirculation circuit of a washing machine is well known in the art, and therefore will not be described in detail.
The washing machine 1 comprises a filter 12 associated or associable to the draining sump 9 and adapted for allowing the passage of washing liquid and for impeding the passage of bodies of fixed dimensions from the washing tub 5 to the draining circuit 10 (and therefore to the pump 11 of the latter). These bodies can be, for example, buttons came off from the laundry, coins or other little objects contained in the pockets of trousers or other clothes and erroneously introduced into the washing machine 1, lint, fluff, etc.
In the embodiments illustrated in the enclosed Figures, the filter 12 is box-shaped (or cup-shaped) and it is advantageously substantially cylindrical, but it may be also prismatic, or cubic, or parallelepiped, or may have any other box-shaped conformation.
The filter 12 advantageously comprises a filtering surface 19 adapted for allowing the passage of a liquid and for impeding the passage of bodies of fixed dimensions; the filtering surface 19 allows the passage of the washing liquid from the washing tub 5 to the draining circuit 10, but impedes the passage of bodies of prefixed dimensions, for example buttons, coins, etc.
In the embodiment illustrated in Figures 1 to 20, the filter 12 is substantially cylindrical, and the filtering surface 19 is comprised in the lateral cylindrical surface of the filter 12.
In a further embodiment, illustrated in Figures 21 to 24, the filtering surface 19 is advantageously part of the bottom surface 12a of the filter 12.
In a further embodiment, not illustrated, the filtering surface 19 is comprised both in the lateral cylindrical surface and in the bottom surface 12a of the filter 12.
Clearly the filter 12 may comprise a single filtering surface or a plurality of filtering surfaces.
Advantageously the filtering surface 19 is provided with a plurality of openings 20 adapted for allowing the passage of liquids, but for avoiding the passage of objects (e.g. coins, buttons, etc.) whose dimensions are higher than a prefixed value depending on the dimensions of the openings 20.
In all the embodiments illustrated in the enclosed figures, the filter 12 may be removed from the draining sump 9, for example for its cleaning, and it can be afterwards repositioned in the draining sump 9.
In this case the filter 12 comprises a coupling device adapted for fixing it in a removable way to the draining sump 9.
Advantageously the coupling device comprises an outwards-projecting peripheral flange 13, projecting from the upper border 12b of the filter 12 and adapted to be put in abutment against the border of the washing tub 5 surrounding the draining sump 9, while the rest of the filter 12 is positioned into the draining sump 9, for avoiding that such filter 12 would fall into the draining sump 9.
In the embodiment illustrated in Figures 2 to 10, the coupling device also comprises snap-fitting means adapted for allowing a snap-fitting connection of the filter 12 to the sump 9. Advantageously the snap-fitting means comprise two or more arms 14a, 14b, fixed to the lateral surface of the filter 12, and elastically deformable so that they may be elastically pressed in a radial direction with respect to the lateral cylindrical surface of the filter 12.
Advantageously, the arms may be connected to the filter 12 in proximity of the bottom surface 12a of the latter, as the arms numbered 14a in Figures 2 to 10, or they may be connected to the filter 12 in proximity of a central region of its lateral cylindrical surface, as the arms numbered 14b; clearly a filter 12 may comprise only arms connected to the filter 12 in proximity of the bottom surface 12a of the latter, or only arms 14b connected to the filter 12 in proximity of a central region of its lateral cylindrical surface, or one or more arms connected to the filter 12 in proximity of the bottom surface 12a of the latter and one or more arms connected to the filter 12 in proximity of a central region of its lateral cylindrical surface.
Advantageously at least part of a lower region 15 of the arms 14a, 14b is sloped in such a way that its distance from the lateral cylindrical surface of the filter 12 increases while approaching the upper border 12b of the filter 12.
Opportunely the free end 16 of the arms 14a, 14b is sloped in an opposite direction with respect to the lower region 15 of the same arm; in other words the arms 14a, 14b in proximity of their free ends 16 are sloped in such a way that their distance from the lateral cylindrical surface of the filter 12 decreases while approaching the upper border 12b of the filter 12.
In the embodiment illustrated in Figures 11 to 24, there are only arms 14b connected to the filter 12 in proximity of a central region of its lateral cylindrical surface; in these embodiments the lower region 15 of the arms 14b has a substantially saw-tooth shape.
An annular riddle 17 advantageously protrudes from the border of the washing tub 5 surrounding the draining sump 9, towards the internal of the latter. With reference to Figures 5 and 7, during the insertion of the filter 12 into the draining sump 9, the lower region 15 of the arms 14a, 14b slides against the annular riddle 17, and, due to the slope of such lower region 15, the arms 14a, 14b are elastically pushed towards the lateral cylindrical surface of the filter 12. After the free end 16 of the arms 14a, 14b goes beyond the annular riddle 17, the arms 14a, 14b elastically move towards the external of the filter 12, positioning with their free ends 16 below the annular riddle 17; the filter 12 is therefore locked to the draining sump 9.
For removing the filter 12 from the draining sump 9, a user has to pull the filter 12 in the opposite direction with respect to the draining sump 9; the free ends 16 of the arms 14a, 14b slide against the annular riddle 17, and, due to their particular slope, they cause the arms 14a, 14b to elastically move towards the lateral cylindrical surface of the filter 12, releasing the arms 14a, 14b from the annular riddle 17, and allowing the free removal of the filter 12.
In a further embodiment, not illustrated, the coupling device may comprise a thread, not illustrated, provided on the lateral cylindrical surface of the filter 12; this thread is adapted to engage a corresponding further thread, also not illustrated, provided on the internal surface of the draining sump 9, so that the filter 12 may be fixed to and removed from the draining sump 9 by screwing.
In a further embodiment, also not illustrated, the coupling device may comprise a bayonet coupling.
Advantageously the filter 12 comprises a grasping element, which will be better described in the following, adapted for allowing a user to easily remove the filter 12 form the draining sump 9.
In a further embodiment thereof, also not illustrated, the filter 12 is fixed to the draining sump 9 and/or obtained in a single-piece construction with the latter; in the last case a user can perform the cleaning of the filter 12 directly in the draining sump 9. It is clear that in the case in which the filter 12 is a single-piece construction with the draining sump 9, the filter 12 and the draining sump 9 partially or totally coincide.
The access to the filter 12, for example for its cleaning and/or replacement, is performed from the internal of the rotatable perforated drum 6 via a suitable aperture, not illustrated, provided on the lateral surface 6a of drum 6 so that in a particular angular position of the latter this aperture faces the draining sump 9; during the functioning of the washing machine this aperture is closed by a closing device 18, for example a lid or a porthole, adapted to selectively close the opening. In the embodiment illustrated in Figure 1, the closing device 18 advantageously comprises a lifter which is pivotable with respect to the lateral surface 6a of the drum 6, so that it can be lifted for allowing the access to the underlying aperture; when not lifted, this lifter operates as a traditional lifter, and it is therefore useful for improving the stirring of the laundry during the rotation of the drum 6.
Advantageously the filter 12 comprises at least a by-pass conduit 21 adapted to direct a flow of washing liquid from the washing tub 5 to the bottom of the draining sump 9, by-passing the filtering surface 19; this flow of washing liquid, therefore, sweeps away the washing/rinsing products which may have been accumulated in the bottom of the draining sump 9, favouring their melting in the washing water.
The flow of washing liquid entering the draining sump 9 via the by-pass conduit 21 crates also a vortical motion in the liquid contained in the draining sump 9 which causes such liquid (in which the washing/rinsing products previously accumulated in the bottom of the draining sump 9 are now melted) to go through the filtering surface 19, so as to reach the washing tub 5.
The by-pass conduit 21 is a conduit adapted for fluidly connecting the internal of the washing tub 5 with the bottom of the draining sump, and which has an imperforate lateral surface, so that substantially all the washing liquid entering the conduit in the washing tub 5 is flown into the draining sump 9.
In particular it is underlined that the by-pass conduit 21 doesn't belong to the filtering surface 19, i.e. it is not comprised in the latter.
Advantageously the shape and the dimensions of the by-pass conduit 21 are adapted for allowing the passage of liquid and for avoiding the passage of foreign bodies of prefixed dimensions, for example coins, rings, buttons and similar small objects; in particular the by-pass conduit 21 is dimensioned in such a way that if a foreign body can't pass through the filtering surface 19, it can't neither pass through the by-pass conduit 21.
Opportunely the by-pass conduit 21 is arranged in such a way that, during the rotation of the drum 6, the flux of washing liquid moved by the rotation of the drum 6 enters the by-pass conduit 21 and, because of the particular shape of the by-pass conduit 21, is accelerated towards the bottom and/or to the lateral surface of the draining sump 9, so as to hit the washing/rinsing products accumulated on the bottom of the draining sump 9 with a force sufficient to sweep them away and to promote their melting in the washing water.
Preferably, as it will be better explained in the following, the by-pass conduit 21 is arranged in such a way that its inlet is positioned, when the filter 12 is positioned in the draining sump 9, above the bottom of the washing tub 5, so as to be stricken by the flux of water moved by the rotatable drum (6) during its rotation.
In a first embodiment, illustrated in Figures 2 to 10, the filter 12 is substantially cylindrical, and the bottom surface 12a of the filter 12 is substantially frustum-conical, with an aperture 12c preferably provided in correspondence of the minor base of the frustum of cone.
In this case, as previously indicated, the filtering surface 19 is comprised in the lateral cylindrical surface of the filter 12.
The filter 12 advantageously comprises a hollow body 22, preferably tubular, projecting from the border of the aperture 12c provided at the bottom surface 12a of the filter 12, partially positioned internally to the lateral cylindrical surface of the filter 12 and extending with its upper end 22a above the upper border 12b of the filter 12, so that when the filter is positioned in the draining sump 9 the upper end 22a of the hollow body 22 protrudes above the bottom of the washing tub 5, so as to be stricken by the flux of water moved by the rotatable drum 6 during its rotation.
Moreover the hollow body 22, extending with its upper end 22a above the upper border 12b of the filter 12, may be grasped by a user in order to remove the filter 12 from the draining sump 9; in this case, therefore, the grasping element of the filter comprises the upper end 22a of the hollow body 22.
Advantageously, but not necessarily, the hollow body 22 is substantially concentric with the filter 12, that is the hollow body 22 is positioned in such a way that its longitudinal axis, not represented, substantially coincides with the longitudinal axis, also not represented, of the filter 12. In a further embodiment, not represented, the hollow body 22 is positioned in such a way that its longitudinal axis doesn't coincide with the longitudinal axis of the filter 12; for example the longitudinal axes of the hollow body 22 and of the filter 12 may be parallel one another, or may also be sloped one with respect to the other.
During the washing cycle, the washing liquid enters the filter 12 from the upper border 12b of the latter, and goes to the draining sump 9 traversing the filtering surface 19 (i.e. traversing the holes 20); foreign bodies contained in the washing liquid and which dimensions are bigger than the holes 20 remains trapped between the filtering surface 19, the bottom surface 12a of the filter 12 and the external surface of the hollow body 22.
In particular, a certain amount of washing/rinsing products (i.e. detergent) which is not yet melted in the washing water may reach the draining sump 9 via the holes 20, and so it may accumulate on the bottom of the draining sump 9.
A hollow guide 23, preferably substantially cylindrical, is advantageously fixed inside the hollow body 22, preferably, but not necessarily, concentrically to the latter, in such a way that there is a first gap 24 between the internal surface of the hollow body 22 and the external surface of the hollow guide 23; advantageously the by-pass conduit 21 comprises this first gap 24.
Opportunely, but not necessarily, the upper end 23a of the hollow guide 23 is opened, and it is placed in correspondence of the free end 22a of the hollow body 22.
Advantageously the hollow body 22 comprises one or more apertures 25, provided on its upper end 22a, fludily communicating with the first gap 24 and adapted for allowing the entrance of washing liquid from the washing tub 5 into the above mentioned first gap 24, and therefore into the by-pass conduit 21. Advantageously the apertures 25 are adapted for allowing the passage of liquids, but for avoiding the passage of objects (e.g. coins, buttons, etc.) whose dimensions are higher than a prefixed value depending on the dimensions of the apertures 25; in particular the dimensions of the apertures 25 are such that if a body can't pass through the filtering surface 19, it can't neither pass through the apertures 25 (in the embodiments illustrated in the enclosed figures, therefore, the dimensions of the apertures 25 are equal or smaller than the dimensions of the holes 20).
Advantageously the apertures 25 are positioned in such a way that when the filter 12 is in the draining sump 9, they are stricken by the flux of water moved by the rotatable drum 6 during its rotation.
Advantageously the filter 12 illustrated in Figures 2 to 10 comprises a sliding element 26 comprising a foot 27, preferably at least partially countershaped to the external surface of the bottom surface 12a of the filter 12, and therefore, in this embodiment, substantially frustum-conical.
Advantageously the sliding element 26 comprises also a pin 28, protruding from the foot 27, slidably arranged inside the hollow guide 23; the pin 28 may therefore slide from an internal position, illustrated in Figure 9, in which the foot 27 contacts a plurality of spacing elements 29 protruding from the external surface of the bottom surface 12a of the filter 12, and an external position, not illustrated, in which a stopping element 30 (for example an annular riddle) provided on the lateral surface of the pin 28, contacts an internal flange 31 protruding from a lower end 23b of the hollow guide 23, towards the internal of the latter.
When the pin 28 is in the internal position, a second gap 32 is therefore obtained between the external surface of the bottom surface 12a of the filter 12 and the foot 27; this second gap 32 fluidly communicates with the above mentioned first gap 24.
Advantageously the cross section of the second gap 32 is smaller than the cross section of the first gap 24, so that a liquid is accelerated when passes from the first gap 24 to the second gap 32.
More generally, the outlet of the by-pass conduit 21 has a cross section (in this embodiment it is the cross section of the second gap 32) which is smaller than the cross section of the inlet of the by-pass conduit 21. In this way the speed of the flux of liquid exiting the by-pass conduit 21 is higher than the speed of the flux of liquid entering the by-pass conduit 21; this ensures that the flux of liquid hits the washing/rinsing products accumulated on the bottom of the draining sump 9 with a force sufficient to sweep them away and to promote their melting in the washing water.
In the embodiment of figures 2 to 10 the by-pass conduit 21 advantageously comprises the apertures 25, the first gap 24 and the second gap 32.
As illustrated in Figures 5 and 7, when the filter 12 is inserted into the draining sump 9, the foot 27 contacts the bottom of the draining sump 9, and the pin 28 is therefore positioned in the internal position; in this position the by-pass conduit 21, comprising the apertures 25, the first gap 24 and the second gap 32, fluidly connects the washing tub 5 and the internal of the draining sump 9, by-passing the filtering surface 19 of the filter 12.
During the washing cycle the washing water, pushed by the rotation of the drum 6, enters the apertures 25 (which in this case corresponds to the inlet of the by-pass circuit 21), goes through the first gap 24 and to the second gap 32 (i.e. passes through the by-pass conduit 21), and is spurted towards the bottom and the lateral surface of the draining sump 9, so as to hit the washing/rinsing products which may be accumulated thereon, sweeping them away and favouring their melting in the washing water. As explained above, the liquid entering the draining sump 9 via the by-pass conduit 21 also causes a vortical motion which favours the re-admission of the water contained in the draining sump 9 (in which the washing/rinsing products previously accumulated in the bottom of the draining sump 9 are now melted) in the washing tub 5.
Advantageously the length of the pin 28 is such that when it is in the above mentioned internal position, illustrated in Figure 9, the free end 28a of the pin 28 protrudes from the upper end 23a of the hollow guide 23, so as to be visible from outside the filter 22. This feature allows a user to visually verify if the filter 12 has been correctly inserted into the draining sump 9; in fact if the filter 12 has not been fully inserted into the draining sump 9, the pin 28 isn't in the internal position, and the free end 28a of the pin 28 doesn't protrude from the upper end 23a of the hollow guide 23, and therefore a user, simply by looking at the upper end 22a of the hollow body 22, may know if the filter 12 is correctly positioned or not.
Figures 11 to 14 illustrate a second embodiment of a filter 12 according to the invention; in this case the filter 12 is substantially cylindrical, and the filtering surface 19 is comprised in the lateral cylindrical surface of the filter 12. The bottom surface 12a of the filter 12 is advantageously substantially frustum-conical.
Also in this case the filter 12 comprises a hollow body 22, preferably tubular, projecting from the border of the aperture 12c provided at the bottom surface 12a of the filter 12, partially positioned internally to the lateral cylindrical surface of the filter 12 and extending with its upper end 22a above the upper border 12b of the filter 12, so that when the filter is positioned in the draining sump 9 the upper end 22a of the hollow body 22 protrudes above the bottom of the washing tub 5, so as to be stricken by the flux of water moved by the rotatable drum 6 during its rotation.
Advantageously the hollow body 22 comprises one or more apertures 25, provided on its upper end 22a, positioned in such a way that when the filter 12 is in the draining sump 9, they are stricken by the flux of water moved by the rotatable drum 6 during its rotation.
From the upper end 22a of the hollow body 22 protrudes, internally to the latter, a septum 33, which subdivides the internal of the hollow body 22 in two first ducts 34a, 34b, each one fluidly communicating with at least one of the one or more apertures 25.
A base 35 protrudes from the end of the septum 33 opposite to the upper end 22a of the hollow body 22; the base 35 is preferably at least partially countershaped to the external surface of the bottom surface 12a of the filter 12, and therefore, in this embodiment, it is substantially frustum-conical.
Between the external surface of the bottom surface 12a of the filter 12 and the base 35 there is a second duct 36, fluidly communicating with the first ducts 34a, 34b. Advantageously the cross section of the second duct 36 (in particularly of the outlet of the second duct 36) is smaller than the sum of the cross sections of the first ducts 34a and 34b, so that a liquid is accelerated when passes from the first ducts 34a, 34b to the second duct 36.
In this second embodiment the by-pass conduit 21 advantageously comprises the apertures 25, the first ducts 34a, 34b, and the second duct 36.
Figures 15 and 16 illustrate a third embodiment of a filter 12 according to the invention; in this case the filter 12 differs from the filter illustrated in Figures 11 to 14 because in the filter 12 illustrated in Figures 15 and 16 the bottom surface 12a of the filter 12 is substantially inverted funnel-shaped (i.e. it is substantially a frustum of cone with its lateral surface rounded), and the base 35 is substantially flat; this results in a different shape of the second duct 36, and therefore of the outlet of the by-pass conduit 21.
Figures 17 and 18 illustrate a fourth embodiment of a filter 12 according to the invention; in this case the filter 12 differs from the filter illustrated in Figures 11 to 14 because in the filter 12 illustrated in Figures 17 and 18 the septum 33 isn't provided with a base, and the first ducts 34a and 34b converge in proximity to the aperture 12c provided at the bottom surface 12a of the filter 12; in this case the by-pass conduit 21 comprises the apertures 25 and the first ducts 34a, 34b, and the aperture 12c.
In addition in this case the filter 12 differs from the filter illustrated in Figures 11 to 14 also because in the filter 12 illustrated in Figures 17 and 18 the bottom surface 12a of the filter is also substantially frustum conical, but the lateral surface of the frustum of cone has an opposite slope with respect to the one of Figures 11 to 14; in other words, from a point of view placed outside the filter 12, the bottom surface 12a of the latter is substantially convex.
Figures 19 and 20 illustrate a fifth embodiment of a filter 12 according to the invention; in this case the filter 12 differs from the filter illustrated in Figures 17 and 18 because in the filter 12 illustrated in Figures 19 and 20 the bottom surface 12a of the filter 12 is substantially inverted funnel-shaped (i.e. it is substantially a frustum of cone with its lateral surface rounded), and because the septum 33 reaches the bottom surface 12a of the filter, in such a way that the first channels 34a and 34b remains separate; in this case, therefore, there are two by-pass circuits 21, one by-pass circuit 21 comprising one of the first ducts 34a and the corresponding aperture 25, and the other by-pass circuit 21 comprising the other first duct 34b and the corresponding aperture 25.
Figures 21 to 24 illustrate a sixth embodiment of a filter 12 according to the invention; in this case the filter 12 is substantially cylindrical, and the filtering surface 19 is comprised in the bottom surface 12a of the filter 12; in particular the filtering surface 19 (and therefore the bottom surface 12a of the filter 12) is provided with a plurality of openings 20 adapted for allowing the passage of liquids, but for avoiding the passage of objects (e.g. coins, buttons, etc.) whose dimensions are higher than a prefixed value depending on the dimensions of the openings 20.
The bottom surface 12a of the filter 12 in this case preferably, but not necessarily substantially flat.
In this case the filter 12 comprises one or more bulkheads 37a, 37b associated to the lateral surface of the filter in such a way that a channel 38a, 38b is defined between each bulkhead 37a, 37b, the lateral surface of the filter 12, and the bottom surface 12a of the filter; the position of the bulkheads 37a, 37b is such that the portion of the bottom surface 12a of the filter 12 defining the channel 38a, 38b doesn't comprise the filtering surface 19.
The channels 38a, 38b are opened in correspondence of the upper border 12b of the filter, so that the washing liquid contained in the washing tub 5 may enter into the channels 38a, 38b; at least one outlet aperture 39 is provided on the bottom surface 12a and/or on the lateral surface of the filter 12 in correspondence of the channels 38a, 38b, so that a liquid may flow out of a channel 38a, 38b via this aperture 39.
In this embodiment, therefore, there are two by-pass conduits 21, each one comprising one of the channels 38a and 38b and the respective outlet opening 39.
Clearly the filter 12 may as well comprise only one channel, and therefore only one by-pass conduit 21, or it may comprise two or more channels, and therefore two by-pass conduits 21.
Preferably, but not necessarily, the upper end 40 of the bulkheads 37a, 37b extends above the upper border 12b of the filter 12, so that when the filter 12 is positioned in the draining sump 9 the inlets of the channels 38a, 38b protrudes above the bottom of the washing tub 5 so as to be stricken by the flux of water moved by the rotatable drum 6 during its rotation.
Advantageously the upper end 40 of the bulkheads 37a, 37b have a curved shape, so as to favour the entrance of the washing liquid into the respective by-pass circuit 21.
Advantageously also in this case the filter 12 comprises a grasping element adapted for allowing a user to easily remove the filter 12 form the draining sump 9; in this embodiment the grasping element comprises a handle 41, preferably fixed to the upper ends 40 of the bulkheads 37a, 37b.
In a further embodiment, not illustrated, the handle 41 may connect two regions of the upper border 12b of the filter 12.
In another embodiment, not illustrated, the by-pass conduit may comprise one or more pipes or ducts connected for example to the lateral surface of the filter 12 and adapted to direct a flow of washing liquid from the washing tub 5 to the bottom of the draining sump 9, by-passing the filtering surface 19 of the filter 12; these one or more pipes or ducts may be associated to the external side of the lateral surface of the filter, or to the internal side of the lateral surface of the filter, or one or more pipes or ducts may be associated to the external side of the lateral surface of the filter, and one or more other pipes or ducts may be associated to the internal side of the lateral surface of the filter.
In another embodiment, also not illustrated, one or more by-pass conduits, adapted to direct a flow of washing liquid from the washing tub to the bottom of the draining sump by-passing the filtering surface of the filter, may be obtained inside the lateral surface of the filter (i.e. these one ore more by-pass conduits pass through the lateral surface of the filter), for example by a suitable moulding of the latter.
It is seen therefore how the invention achieves the proposed aim and objects, there being provided a washing machine which, thanks to the one or more by-pass conduits provided on the filter for directing a flow of washing liquid from the washing tub to the bottom of the draining sump, by-passing the filtering surface, allows sweeping away the washing/rinsing products accumulated in the bottom of the draining sump, favouring the melting of these products in the washing water and the re-admission of the water containing these melted products in the washing tub.
This allows obtaining an efficient usage of the detergent and of the other washing/rinsing products, optimizing in this way the consumptions of the washing/rinsing products, and therefore reducing also the environmental pollution.
Moreover the one or more by-pass conduits ensuring the removal of the washing/rinsing products accumulated in the bottom of the draining sump, avoids that these accumulated washing/rinsing products could obstruct the draining circuit, reducing in this way the risk of flooding of the washing machine.
In addition, a filter according to the invention, provided with one or more by-pass conduits, may be used, instead of a traditional filter, in a known washing machine, so as to obtain, also in this known washing machine, the sweeping away of the washing/rinsing products accumulated in the bottom of the draining sump, so as to favour the melting of these products in the washing water and the re-admission of the water containing these melted products in the washing tub.

Claims

Washing machine (1) comprising:
- a washing tub (5);

- a draining sump (9) fluidly communicating to the internal of said washing tub (5) and fluidly connected to a draining circuit (10);

- a filter (12), associated or associable to said draining sump (9) and provided with a filtering surface (19) adapted for allowing the passage of a liquid and for impeding the passage of bodies of fixed dimensions;
characterized in that
said filter (12) comprises at least one by-pass conduit (21) adapted for directing a flow of washing liquid from said washing tub (5) to the bottom of said draining sump (9), by-passing said filtering surface (19).
Washing machine (1), according to claim 1, wherein said by-pass conduit (21) comprises a conduit adapted for fluidly connecting the internal of said washing tub (5) with the bottom of said draining sump (9), and which has an imperforate lateral surface, so that substantially all the washing liquid entering said conduit in the washing tub (5) is flown into said draining sump (9).
Washing machine (1), according to claim 1 or 2, wherein the shape and the dimensions of said at least one by-pass conduit (21) are adapted for allowing the passage of liquid and for avoiding the passage of foreign bodies of prefixed dimensions.
Washing machine (1), according to one or more of the previous claims, wherein the shape and the dimensions of said at least one by-pass conduit (21) are such that if a foreign body can't pass through said filtering surface (19) it can't neither pass through said by-pass conduit (21).
Washing machine (1), according to one or more of the previous claims, wherein said at least one by-pass conduit (21) is dimensioned in such a way that the speed of a liquid exiting said at least one by-pass conduit (21) is higher than the speed of a liquid entering said at least one by-pass conduit (21).
Washing machine (1), according to claim 5, wherein the cross-section of the outlet of said at least one by-pass conduit (21) is smaller than the cross-section of the inlet of said by-pass conduit (21), so that the speed of the flux of liquid exiting said by-pass conduit (21) is higher than the speed of the flux of liquid entering said by-pass conduit (21).
Washing machine (1), according to claim 6, wherein the inlet of said at least one by-pass conduit (21) is positioned, when said filter (12) is positioned in said draining sump (9), above the bottom of said washing tub (5), so as to be stricken by the flux of water moved by said rotatable drum (6) during its rotation.
Washing machine (1), according to one or more of the previous claims, wherein said filter (12) is removable from said draining sump (9).
Washing machine (1), according to claim 8, wherein said filter (12) comprises a coupling device adapted for fixing it in a removable way to said draining sump (9).
Washing machine (1), according to claim 8 or 9, wherein said filter (12) comprises a grasping element adapted for allowing a user to easily remove said filter (12) form said draining sump (9).
Filter (12) for the draining circuit of a washing machine (1), comprising a filtering surface (19) adapted for allowing the passage of a liquid and for impeding the passage of bodies of fixed dimensions, characterized in that said filter (12) comprises at least one by-pass conduit (21) adapted for directing a flow of liquid from one side of said filtering surface (19) to the other side of said filtering surface (19), by-passing said filtering surface (19).
Filter (12), according to claim 11, wherein the shape and the dimensions of said at least one by-pass conduit (21) are adapted for allowing the passage of liquid and for avoiding the passage of foreign bodies of prefixed dimensions.
Filter (12), according to claim 11 or 12, wherein the shape and the dimensions of said at least one by-pass conduit (21) are such that if a foreign body can't pass through said filtering surface (19) it can't neither pass through said by-pass conduit (21).
Filter (12), according to one or more of claims 11 to 13, wherein said at least one by-pass conduit (21) is dimensioned in such a way that the speed of a liquid exiting said at least one by-pass conduit (21) is higher than the speed of a liquid entering said at least one by-pass conduit (21).
Filter (12), according to one or more of claims 11 to 14, wherein the cross section of the outlet of said at least one by-pass conduit (21) is smaller than the cross section of the inlet of said by-pass conduit (21), so that the speed of the flux of liquid exiting said by-pass conduit (21) is higher than the speed of the flux of liquid entering said by-pass conduit (21).