EP2118355B1

EP2118355B1 - Laundry washing machine with filter in the wash tub

Info

Publication number: EP2118355B1
Application number: EP08719185A
Authority: EP
Inventors: Luisa D'alessandro; Dino Bongini; Paolo Faraldi; Costantino Mariotti
Original assignee: Indesit Co SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2007-03-02
Filing date: 2008-02-29
Publication date: 2012-11-21
Anticipated expiration: 2028-02-29
Also published as: WO2008107762A3; PL2118355T3; WO2008107762A2; ITTO20070157A1; EP2118355A2; ES2399369T3

Description

The present invention relates to a washing machine according to the preamble of claim 1, and is particularly applicable to the field of household laundry washing and washing/drying machines, as shown from GB 725123A , UK 20040019857A , JP 07275591A , JP 59077893A , JP 01230394A .
In these machines, textile items are loaded into a wash tub wherein they are suitably treated by means of a wash liquid, which is typically pure water or water containing dissolved detergents, according to the various phases of the operating cycle.
In fact, the laundry treatment takes place in several phases, which comprise at least one wash phase and at least one rinse phase; usually each phase includes a wash liquid supply step and a wash liquid drain step.
The temperature of the wash liquid in the tub varies according to the type of laundry to be washed and to the type of dirt to be removed: in particular, the more resistant the dirt deposits to be removed from the textiles, the higher the temperature used.
In some cases, when using high wash temperatures (e.g. a temperature of 50°- 60° or higher), coloured items fade, and the colour disperses into the wash liquid and is then absorbed by the other textile items contained in the tub. In short, a phenomenon takes place which is called "bleeding" by those skilled in the art of laundry washing machines, this phenomenon being a serious problem because those textile items that absorb the colour dispersed in the wash liquid get irreversibly damaged.
In order to prevent this problem from occurring, the user of a washing or washing/drying machine must necessarily select the laundry items according to their colour.
Moreover, when the laundry is very dirty, the wash liquid tends to get saturated with impurities, so that the treatment carried out during a certain wash phase may become gradually less effective due to the pollution in the liquid.
Patent application JP2000-185191 has disclosed a household laundry washing machine comprising a device providing anodic oxidation of the dyestuff dispersed in the wash liquid; said device comprises an electrolytic cell capable of separating dyestuff and/or contaminating substances when a direct voltage is applied across its two electrodes.
The device described in patent application JP2000-185191 has a number of drawbacks: in the first place, it is too costly to be actually applied to household washing or washing/drying machines; secondly, the electric power required for activating the electrolytic cell has a strong effect on machine consumption; thirdly, the device is difficult to maintain, so that its effectiveness decreases with time and wear.
It is an object of the present invention to provide a laundry washing or washing/drying machine which is alternative to the one described in patent application JP2000-185191 and therefore not suffering from the drawbacks associated with the latter, and which allows to carry out a more effective wash treatment by removing impurities released into the wash liquid during the wash and/or rinse phases, in particular by removing any dyestuff residues, thus reducing the textile dyestuff phenomenon during the wash and/or rinse phases.
It is another object to provide a laundry washing or washing/drying machine which allows to solve the above-mentioned problems through a low-cost solution applicable to household machines.
These and other objects are achieved by means of a washing machine incorporating the features set out in the appended claims.
The general idea at the basis of the present invention is to provide a washing machine, in particular a household laundry washing or washing/drying machine, which comprises filtering means adapted to filter the wash liquid contained in the tub. To this end, the Applicant has thought of associating filtering means with a component being present inside the machine, which meets the requirement of coming in contact with the wash liquid when the machine is operating.
In particular, the Applicant has found the so-called "lifter" (i.e. the element applied to the drum and adapted to drag and/or lift the textile items during the treatments) to be the component most suited to being associated with wash liquid filtering means.
Further objects and advantages will become apparent from the following detailed description pertaining to a preferred but non-limiting embodiment example as shown in the annexed drawings, wherein:

Fig. 1 schematically shows a laundry washing machine according to the present invention;
Fig. 2 and Fig. 3 are a front view and a top view, respectively, of a lifter of the washing machine of Fig. 1;
Fig. 4 and Fig. 5 are two different schematic sectional views of the lifter shown in Fig. 2 and Fig. 3;
Fig. 6 schematically shows the washing machine of Fig. 1 during the execution of a laundry wash treatment.

In the above-listed drawings, the same reference numerals are used in order to designate equivalent items; they are not scale drawings.
Fig. 1 shows a washing machine 1, in particular adapted to carry out at least one wash treatment on textile items and to be used within a household environment, which represents a possible embodiment of the present invention.
The washing machine, designated 1 as a whole in Fig. 1, will hereafter be referred to as "laundry washing machine": it is worth specifying that the term "laundry washing machine" includes any machine which is capable of carrying out at least one wash treatment on textile items (and therefore also that machine which is traditionally called "washing/drying machine"), whether the front-loading or top-loading type. Preferably, the machine called "laundry washing machine" can also carry out a rinse treatment on textile items, wherein the quantity of washing agents remaining after the execution of a previous wash treatment is removed from the textile items.
As a non-limiting example of washing machine 1 according to the present invention, Fig. 1 shows a front-loading laundry washing machine 1.
The latter comprises an external structure 10, a tub 2 arranged inside said structure and adapted to contain wash liquid (the "wash liquid" being water or any solution of water and washing agents), a drum 3 rotating inside tub 2 and adapted to contain the textile items to be treated, and at least one element 9 applied to the inner surface of drum 3 and adapted to drag and/or lift the textile items during a wash and/or rinse treatment. According to the present invention, element 9 comprises filtering means adapted to filter the wash liquid contained in tub 2 during at least one phase of the wash or rinse treatment. Said filtering means perform the function of at least partly removing the dyestuff and/or contaminating substances dispersed in the wash liquid by absorbing and/or neutralizing and/or separating said substances.
Hereafter dragging and/or lifting element 9 will be referred to as "lifter", this name being commonly used in this technical field.
Lifter 9 is a special one since it comprises filtering means; typically, there are also a plurality of traditional lifters 80; 90, which may be made of plastic preferably coated with a layer of a soft and/or elastic material: thus, the textile items will not be subject to possible slight damage due to hitting and/or friction against lifters 80; 90 during the rotation of drum 3.
There may also be a lifter comprising means for containing washing agents and/or additives, similar to the one described in patent application WO90/00641 ; lifters 9; 80; 90 are so sized that the centre of gravity of lifter system 9; 80; 90 lies in the axis of rotation 8 of drum 3, thus not causing any unbalance which might damage laundry washing machine 1 when drum 3 is rotating at high speed (e.g. during the spin phase, wherein drum 3 may reach angular speeds exceeding 1,000 rpm).
Lifter 9 is secured to drum 3 in such a way that it is adjacent to the inner surface of drum 3, in particular to the inner surface of the sides of drum 3; like any other lifter 80;90 possibly present in laundry washing machine 1, lifter 9 may be made of plastic material coated with a layer of a soft and/or elastic material. However, it may differ in shape and volume from any other lifter 80;90 being present in washing machine 1.
Laundry washing machine 1 comprises a hydraulic circuit adapted to supply and drain water or wash liquid to/from tub 2; the schematic representation of Fig. 1 only shows a few elements of said hydraulic circuits, among which drain duct 15 and pump 13, adapted to generate the drain flow.
Upstream of pump 13 there is a trap filter 14, the main function of which is to stop any solid particles entering drain duct 15 before they can reach pump 13, which would otherwise be seriously damaged. Laundry washing machine 1 must be maintained periodically by cleaning trap filter 14, i.e. by removing the solid particles accumulated thereon, which represent an obstacle to the wash liquid flow in drain duct 15.
Laundry washing machine 1 may be of the type described in patent application EP1057922 , wherein pump 13 is integrated into tub 2; for further detail, reference should be made to this document, the contents of which are assumed to be incorporated in the present description.
Advantageously, the hydraulic circuit of laundry washing machine 1 comprises a recirculation duct 20 adapted to bring back into the tub 2 the wash liquid previously taken from said tub 2, thus generating a liquid flow against the textile items contained in drum 3. In order to supply recirculation duct 20, a diverter valve 22 is located downstream of pump 13, which valve is adapted to direct the wash liquid flow generated by pump 13 into recirculation duct 20 or duct 15.
Figs. 2-5 show some views of a lifter 9 manufactured according to the teachings of the present invention and comprising filtering means.
More precisely, Fig. 2 is a side view of lifter 9, Fig. 3 is a view of lifter 9 (i.e. it shows lifter 9 as viewed by an observer looking in the direction of the axis of rotation 8 of drum 3 from the inner surface of drum 3, lifter 9 being interposed between the observer and axis 8), and Figs. 4-5 are two sectional views of lifter 9 along respective planes called section plane A and section plane B, which are orthogonal to axis of rotation 8 of drum 3. The filtering means, the function of which is to filter the wash liquid in tub 2 by removing at least partly any dispersed dyestuff and/or contaminating substances, comprise a filter 23 having a matrix or substrate adapted to exert a chemical and/or physical filtering action on said dyestuff and/or contaminating substances by means of active sites provided on the filter itself.
As shown in Figs. 2-5, filter 23 is housed in a first chamber 12 obtained within lifter 9; in addition, filter 23 can be removed from lifter 9: thus, the user of laundry washing machine 1 is given the possibility of removing filter 23 when it has become exhausted, in order to replace it with a new one.
To this end, means for accessing first chamber 12 are provided which in the example shown in Figs. 2-5 consist of a chamber lid 31 fitted with suitable means (e.g. a pair of hinges) allowing it to rotate about an axis 7, which is parallel to axis of rotation 8 of drum.
In order to replace filter 23, the user first opens lid 31 (this step may be facilitated by grip means 32, such as, for example, a particular shape of the free end of lid 31), and then extracts exhausted filter 23 and replaces it with a new one; finally, he/she closes lid 31 again.
As an alternative to the above-described procedure, filter 23 may be replaced by removing whole lifter 9, which is detachable from drum 3, or else (according to a solution verified by the Applicant to be particularly efficient in view of an ergonomic use of laundry washing machine 1) the filter may be replaced by translating filter 23 in the axial direction (i.e. the direction in which lifter 9 extends), thus sliding said filter 23 through an aperture (which can preferably be re-closed) obtained in front wall 40 of lifter 9.
With this solution, the extraction of exhausted filter 23 and the subsequent insertion of a new filter into first chamber 12 may be made easier by providing laundry washing machine 1 with a system for hooking lifter 9, which allows the user to raise at least the front portion of lifter 9 relative to the surface of drum 3 and/or to move it forwards.
As aforementioned, filter 23 consists of a material substrate which makes it capable of exerting a physical filtering action on dyestuff and/or contaminating substances dispersed in the wash liquid contained in tub 2, and/or a chemical filtering action through active sites provided on the surface of filter 23 (which typically adsorb said dyestuff and/or contaminating substances); for this purpose, its geometry is such that the area/volume ratio is maximized.
A cellulose fabric having a cationized surface is a preferred example of a suitable substrate which may be used for manufacturing filter 23: other materials may however be used as well (e.g. even activated carbon, although laboratory tests carried out by the Applicant have shown that cationized cellulose should be preferred over activated carbon because it is more effective in absorbing and/or neutralizing and/or separating dyestuff and/or contaminating substances).
The substrate used for manufacturing filter 23 may be either a rigid material (as shown in the drawings annexed to the present description) or a flexible material; in the latter case, filter 23 is held in its housing inside lifter 9 by means of an inert support (e.g. a rigid plastic frame).
The filtering means may comprise, as an alternative to or in association with filter 23, a different filtering element such as, for example, an ultraviolet ray source (lamp or LED), which may be housed within lifter 9.
Such a source, in fact, is suitable for purifying the wash liquid neutralizing by dissociation a part of the contaminating substances dispersed in said liquid.
It is also possible to obtain a synergic effect by using, in association with the ultraviolet ray source, a filter including a material which can be activated by ultraviolet light, e.g. titanium dioxide: said filter releases particles in the wash liquid which, when illuminated by an ultraviolet radiation, become capable of effectively removing any dyestuff and/or contaminating substances dispersed in the wash liquid.
For filter 23 housed in lifter 9 to be able to carry out its filtering action, it is necessary that, when laundry washing machine 1 is in operation, it comes directly in contact with the wash liquid contained in tub 2. For this purpose, lifter 9 is provided with a series of apertures which allow liquid substances to flow inside of it and lap or cross the surface of filter 23.
Lifter 9 also comprises means for spraying the textile items contained in drum 3 during a wash or rinse treatment.
To this end, lifter 9 shown in Figs. 2-5 can also be used as a sprayer, since it can collect wash liquid inside (which wash liquid is loaded when lifter 9 goes through the wash bath as drum 3 rotates) and can subsequently release the collected wash liquid (which preferably has also been filtered) through one or more jets flushing from above the textile items contained in drum 3.
In particular, lifter 9 comprises a plurality of outlet channels 83 through which (during the operating phases of laundry washing machine 1 wherein drum 3 is rotating about its axis 8) the wash liquid, after having entered first chamber 12 and having been filtered by filter 23, is then released back into tub 2, thus improving the soaking of the textile items contained in drum 2 and making the wash liquid filtering action more homogeneous. Outlet channels 83 may have any shape (e.g. they may have a circular section) and may be distributed freely on the surface of lifter 9 (e.g. they may be arranged in several rows, preferably offset to one another).
Lifter 9 is particularly suitable for use as a sprayer when laundry washing machine 1 comprises, as in the case shown in Fig. 1, a recirculation duct 20.
In fact, lifter 9 comprises a through hole 88 obtained in its back surface, through which wash liquid can be introduced into first chamber 12 from recirculation duct 20; a recirculation step which may be carried out by laundry washing machine 1 according to the present invention is shown in Fig. 6.
Recirculation flow P is conveyed through through hole 88 from recirculation duct 20 to lifter 9, where it is filtered by filter 23 and is then divided into a plurality of spouts S exiting lifter 9 through outlet channels 83 and hitting textile items 11 contained in the drum.
The above-described recirculation step is adapted to maximize the quantity of wash liquid that is filtered when laundry washing machine 1 is in operation, thereby also maximizing the quantity of dyestuff and/or contaminating substances absorbed and/or neutralized and/or separated by the filtering means comprised in lifter 9.
Laundry washing machine 1 shown in Fig. 6 is therefore particularly effective in countering the so-called "bleeding" of textile items 11 during wash and/or rinse treatments; the effectiveness of laundry washing machine 1 can be improved even further by arranging auxiliary filtering means along recirculation duct 20: these auxiliary filtering means may comprise a filter which is similar to filter 23 and/or a filtering device of a different type.
Lifter 9 also comprises means for inspecting and/or maintaining at least one component of laundry washing machine 1; according to the embodiment of lifter 9 shown in Figs. 2-5, in fact, said lifter may also be used in a laundry washing machine 1 as an inspection device. It is worth specifying that the presence of said inspection and/or maintenance means in lifter 9 according to the present invention is absolutely optional.
To this end, lifter 9 comprises a movable element which, if opened when laundry washing machine 1 is off and lifter 9 is in the position shown in Fig. 1, allows the user to inspect the condition of trap filter 14 located upstream of pump 13 and to remove any solid deposits accumulated on trap filter 14.
In the example shown in Figs. 2-5, the movable element consists of a second lid 70 fitted with suitable means (e.g. a pair of hinges) which allow it to rotate about axis 77, said axis 77 being in particular parallel to or coinciding with axis of rotation 7 of first lid 31; second lid 70 can be opened easily thanks to second grip means 72 associated therewith. After having raised second lid 70, the user has maintenance access to trap filter 14 through an aperture 71 obtained in the bottom of lifter 9, which is above trap filter 14 when lifter 9 is in the position of Fig. 1. The dimensions of aperture 71 are preferably such that a hand can pass through it.
Lifter 9 shown in Figs. 2-5 comprises a second chamber 78, separated from first chamber 12 by a dividing wall 79; however, it is also possible to provide a lifter 9 comprising a single inner chamber which houses filter 23 and through which one can reach aperture 71 in order to maintain trap filter 14.
If drum 2 is mounted in laundry washing machine 1 in such a manner that its axis of rotation 8 is inclined relative to the horizontal plane, said inclination being approximately 10°, lifter 9 according to the present invention will advantageously have at least one port adapted to allow the wash liquid to flow out of drum 2.
Said port is located in that portion of lifter 9 which is lowest when lifter 9 is in the position of Fig. 1: in the non-limiting example shown in Figs. 2-5, it has been assumed that said portion is the lower part of second chamber 78, and that said port is provided by means of a slit 76 obtained under second grip means 72 of second lid 70.
The important results and advantageous effects of the invention are apparent from the above description.
First of all, it allows to overcome the drawbacks of the laundry washing machine described in patent application JP2000-185191 . As a matter of fact, the washing machine according to the present invention offers a low-cost, easy-to-maintain system for filtering dyestuff and/or contaminating substances dispersed in the wash liquid and for countering the textile bleeding phenomenon.
Secondly, it provides a washing machine comprising a "multifunction" lifter, i.e. a lifter capable of combining traditional functions with a number of additional functions, such as:

i) filtering element, the inside of the lifter being accessible to the wash liquid and comprising a filtering means capable of, among other things, absorbing and/or neutralizing and/or separating any dyestuff released by textile items during the wash;
ii) sprayer, the lifter comprising a plurality of outlet channels through which the wash liquid flowing out of the lifter is divided into a plurality of spouts flushing the textile items contained in the drum, and
iii) inspection device, the lifter comprising a movable element through which the drain pump filter can be reached when the lifter is in a predetermined position.

Claims

Washing machine (1), in particular a household laundry washing or washing/drying machine, capable of carrying out at least one wash and/or rinse treatment on textile items, comprising:
- a tub (2) adapted to contain wash liquid;

- a drum (3), rotating inside said tub (2) and adapted to contain textile items to be treated;

- at least one element (9) applied to the inner surface of said drum (3) and adapted to stir the textile items as the drum (3) rotates in the tub, said element (9) comprising filtering means adapted to filter the wash liquid within said tub (2),
characterized in that
said element (9) comprises means for spraying the textile items contained in the drum (3) during said wash and/or rinse treatment.
Washing machine (1) according to claim 1, wherein said element (9) comprises a plurality of outlet channels (83) through which a wash and/or rinse liquid is released back into the tub (2), in particular after having been filtered by said filtering means.
Washing machine (1) according to claim 1 or 2, wherein said filtering means can remove at least a part of the dyestuff and/or contaminating substances dispersed in the wash liquid by absorbing and/or neutralizing and/or separating said substances.
Washing machine (1) according to claim 3, wherein said filtering means comprise a filter (23) having a substrate adapted to exert a chemical and/or physical filtering action on said dyestuff and/or contaminating substances by means of active sites provided thereon.
Washing machine (1) according to claim 4, wherein said filter (23) can be removed from said element (9), so that it can be replaced when exhausted.
Washing machine (1) according to claim 5, wherein an aperture, which can preferably be re-closed, is obtained in the front wall (40) of said element (9) in order to allow the filter (23) to be removed and replaced, said washing machine (1) additionally comprising a system for hooking said element (9), which allows at least the front portion of said element (9) to be raised relative to said drum (3) and/or moved forwards when replacing said filter (23).
Washing machine (1) according to any of claims 4, 5 or 6, wherein said filter (23) is made of cellulose fabric having a cationized surface.
Washing machine (1) according to any of claims 4, 5, 6 or 7, wherein the material used for manufacturing said filter (23) is a flexible one, and said filter (23) is held in its housing inside said element (9) by means of an inert support.
Washing machine (1) according to any of the preceding claims, wherein said filtering means comprise an ultraviolet ray source.
Washing machine (1) according to any of the preceding claims, wherein said element (9) comprises means for inspecting and/or maintaining at least one component of said laundry washing machine (1).
Washing machine (1) according to claim 10, wherein said component to be inspected and/or maintained is a trap filter (14) associated with a pump (13) of the laundry washing machine (1), said pump (13) being preferably integrated into said tub (2).
Washing machine (1) according to any of the preceding claims, which comprises a recirculation duct (20) adapted to bring back into said tub (2) the wash liquid previously taken from said tub (2).
Washing machine (1) according to claim 12, comprising a diverter valve (22) adapted to direct the wash liquid flow generated by a pump (13) of the laundry washing machine (1) into the recirculation duct (20) or a drain duct (15).
Washing machine (1) according to claim 12 or 13, wherein auxiliary filtering means are arranged along said recirculation duct (20).