EP3090097A1

EP3090097A1 - Washing/drying machine with cleaning device for a drying air filter

Info

Publication number: EP3090097A1
Application number: EP14830710.1A
Authority: EP
Inventors: Giovanni Bombardieri; Gianluca Ferro; Lorenzo Verdini
Original assignee: Indesit Co SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2013-12-31
Filing date: 2014-12-18
Publication date: 2016-11-09
Also published as: WO2015101892A1; ITTO20131101A1

Abstract

The invention relates to a washing/drying machine equipped with a system to prevent the drying air filter ( 26 ) from being clogged by the filaments coming off garments during the washing/drying cycle. To this aim, a cleaning device (30) is provided at the filter location, said filter having nozzles (31) spraying water against the filter (26) to remove the filaments that have built up thereon.

Description

"WASHING/DRYING MACHINE WITH CLEANING DEVICE FOR A DRYING AIR FILTER"

DESCRIPTION

The present invention relates to a washing/drying machine, that is to say those appliances used for household or even industrial/commercial applications devised to wash and dry laundry in general.

These machines have, therefore, some elements in common with washing machines, e.g., the tub or washing chamber wherein a basket or rotary drum is housed; garments or laundry to be treated are loaded into the basket either through a frontal or top door according to the type of machine.

The basket rotation keeps the laundry moving during washing and/or drying phases, in which the tub is supplied with water or air, respectively.

During the washing/drying machine operating cycle, the load - consisting of garments, laundry and the like - generally releases filaments that are evacuated through the drain, which takes place simply and directly during the washing phases. Indeed, water is loaded and discharged many times during such phases, with washing liquids or rinsing water etc., so that filaments coming off fabric are removed from the laundry and evacuated together with the water being drained.

Differently, during laundry drying the filament fluff produced by friction between garments and the internal wall of the basket (inc easingly as moisture decreases), are dragged from the air flow circulating within the machine and brushing against the garments being dried in the basket; said filaments cannot be evacuated in the same way they are during washing, since no water is supplied to the basket during drying .

It can thus be understood that drying air must be cyclically filtered in order to prevent the fan and related electrical resistance from being damaged. To this aim, it is known in the art to take air from the wa shi ng / dryi ng tub, filtering it, reducing its humidity and sending it back into the tub.

For the filtering air is sent through a filter comprising a mesh or net made of metal, plastic or the like, fitted onto a wall of the washing/drying chamber (in particular, on the back wall right at the outlet to the drying circuit) , said mesh or net being enough close-meshed to hold the filaments coming off fabric. It can be easily understood that filament fluff that build up onto the filter reduces its air- passage section and cause load pressure losses that slow down the air flow, which results in a limitation of the overall efficiency of the laundry drying cycle .

The present invention aims to overcome this problem affecting the prior art.

Therefore, the technical problem underlying the present invention is that of providing a washing/drying machine having structural and functional features such that it can maintain regular and efficient air filtering, thereby ensuring a proper laundry drying cycle.

The idea for solvering said problem is that of removing from the filter the bulk of filaments taken away from laundry dried by the air that circulates through the washing/drying machine: in this way it is possible to prevent the filter from getting clogged quickly, thereby preserving its efficiency and reducing load losses for a longer time. To achieve this result the teaching of the invention is that of spraying water where filaments build up along the drying air flow path.

The features of the invention as a whole are set out specifically in the claims appended to this description .

Said features will become more apparent from the following description of a preferred, but non exclusive, embodiment shown in the annexed drawings, wherein :

- Fig. 1 is a perspective view of a washing/drying machine according to the invention;

- Fig. 2 is a perspective view of the washing/drying tub or chamber of the machine shown in Fig. 1, with the drying circuit associated thereto;

- Fig. 3 is a perspective view of the washing/drying tub of the machine shown in Fig. 1, seen from a different angle than in Fig. 2;

- Fig. 4 shows the tub of figures 2 and 3 with a wall removed, so as to make its internal parts visible.

- Fig. 5 is a detailed view of a system for cleaning the filter of the washing/drying machine shown in previous figures;

- Fig. 6 is a partial sectional view of the detail of Fi gure 5 ;

- Fig. 7 shows a different embodiment of the tub from Figures 2 and 3 with a wall removed, so as to make its internal wall visible;

Fig. 8 shows some possible variants of surface finish of the wall for the tub shown in fig. 7.

With reference to the figures listed hereabove, in drawings the reference numeral 1 indicates as a whole a washing/ drying machine according to the present invention, comprising an outer structure shaped substantially like a parallelepipedon cabinet, with a frontal panel 3 where controls are found (e.g. Push^¬ buttons, knobs, etc.) for users and different indicators, warning lights, screens (e.g., display) or other means such as the washing liquid dispenser drawer, used for controlling and operating the machine 1.

It is opportune to note that for the sake of simplicity and clarity, in this description reference will be made to the components of the washing/drying machine 1 useful to understand the invention; however, for further information reference can be made to what is known in the art, e.g. the washing/drying machines manufactured by the current applicant or described in European patent applications EP 2116647, EP 2281081, EP1907616, EP 1775368, EP 1647621 and others, which are here set out in full and whose content is deemed to be incorporated in this description, given its applicability.

Frontally in cabinet structure 2 there is the washing/drying machine aperture 4 for loading, closed by a door 5.

Inside the structure 2 of the machine, a washing/drying chamber or tub 10 is housed wherein a basket 11 for loading laundry to be treated is supported in a manner known per se. Said chamber or tub 10 is intended for the washing and drying (in short, washing/drying) of laundry, since in a machine such as the one being considered here, the chamber or tube performs a dual function of a water container during washing phases, and of a drying chamber during drying .

The basket is conventionally shaped as a drum with a perforated wall to allow the passage of water as can be seen from figures 1 and 4, said basket being fitted with vanes or inner protrusions 12 to stir the load following rotation, with machine 1 in operation .

Said chamber 10 comprises a substantially cylindrical skirt or side wall 15 - which can also be slightly convex - posteriorly closed by a rear or back wall 16, whereas frontally it has a collar 17 onto which a sealing gasket 18 is applied with aperture 4 of the casing 12 of the washing/drying machine.

Externally to the washing/drying chamber 10 there is a circuit 20 for air drying, which comprises a suction line 21 also acting as a condenser and a supply line 22, between which a fan is operated 23 for air circulation .

In particular, the supply line 22 extends from the collar 17 of the chamber 10 to the fan 23 while the suction line extends from said fan 23 to an inlet formed in the back wall 16 of the chamber 10 where the filter 26 is located.

Said filter is in a slightly eccentric position with respect to the rotation axis of the basket, wherein on the chamber 10 back wall 16 the support and/or rotation means 28 of the basket 11 such as the shaft, the roller bearings, the pulleys etc. (not shown in the drawings as known per se) are located.

The filter (26) is made in any appropriate manner, e.g., with a grating or net made of metal or plastics whose mesh is suitably sized to hold filaments coming off garments treated in the washing/drying machine 1; the mesh can be polygonal in shape (i.e., square, rectangular, hexagonal) circular or else, with a passage space of less than 1 mm². Externally to chamber 10, on filter 26 there is a device 30 for cleaning the filaments, which comprises a series of nozzles 31 arranged on a matrix having a similar shape to that of the filter itself, against which their respective water jets are directed, so as to hit the filter's back surface and cause filaments held thereby, to detach due to the impact of said water jets against the surface.

As shown in figures 5 and 6, in this example said nozzles are supported by a header 32 connected to a hydraulic system for water supply, comprising a solenoid valve 35 associated to the water mains to which the washing/drying machine is connected, said header 32 being also connected in an advantageous embodiment to a branch 36 for recirculating water drained from the bottom of the washing/drying chamber 10 through a first drain 33. The connection between said solenoid valve 35 and the header 32 can be with or without pressure head, thereby guaranteeing that jets coming out of the nozzles 31 have enough pressure to effectively hit the filter 26.

Said header 32 with nozzles 31 is housed in the suction line or condenser 21, fastened to the back wall 16 of the washing chamber 10; according to an advantageous embodiment, in the low portion of the suction line 21 a second drain is found 37 for the water sprayed by the nozzles 31, as well as for the condensation water building up in the condenser 21, which consists of a hole in the back wall 16 of the chamber 10.

In this way, the water collected on the bottom of the line 21 is evacuated to chamber 10 from which it exits through the first drain 33. Alternatively, the hole on the condenser 21 can communicate directly with the drainage pump 38. The water built up on the bottom of the tub 10 during drying is drained by means of the pump 38: in this way, the filaments dispersed in water are expelled from the machine.

According to a preferred embodiment, the cleaning device 30 of the filter 26 provides for the recirculation of water especially condensation water created during laundry drying through branch 36 by a pump 38 with enough pressure to effectively hit the filter 26.

In this case, the hydraulic circuit also features a diverter valve 39 directing the flow either to the drain or to the recirculation branch 36, to be sent back to the nozzles 31. Indeed, if water turns out to be contaminated with filaments it is sent by the valve to the drain, thereas if that is not the case, it is used again for the filter cleaning cycle. From what has been described above it is possible to understand how the washing/drying machine 1 solves the technical problem previously outlined and underlying the present invention.

Indeed, when the filter 26 is found to be clogged by filaments removed from laundry being treated during machine operation, the cleaning device 30 is activated and water is sprayed by the nozzles 31 against the filter 26 so as to remove filaments therefrom.

Continuous functioning can be provided for the cleaning device 30 during the drying phase or, for optimized water consumption, intermittent and/or pulsed functioning whereby said device 30 is activated only at special time intervals during drying phases, or alternatively in one or more sub- phases specifically aimed to cleaning oh filter 26.

Preferably, the device 30 is activated at the end of a drying cycle or anyway before a new washing cycle starts; under such circumstances, with the machine unloaded or with laundry contained in the basket 11, water is supplied to nozzles 31 from the water mains by actuating the inlet valve 35.

According to a preferred manner of operating, said device 30 is activated when relative humidity in the chamber 10 falls below a preset threshold. Indeed, it is only from that moment onwards that filaments or lint start coming off laundry in significant amounts. For instance, a pulsed activation of the device 30 can be provided when residual humidity in the camber 10 reaches 10%, and with a duty cycle that depends on the pressure and/or volume of water supplied to the shower head 32. Residual humidity in the chamber is measured in a manner and with means known in the art, e.g. using the teachings of patent application GB2154721A.

The filter, then, is washed with water from the mains that is evacuated from the bottom of the tub through the drain 33; in this case, the diverter valve 39 sends the washing water from the nozzles directly to the drain.

Differently, if no filaments are detected in the water, it can be reused to wash the filter 26; this operating cycle can be performed either in a programmed manner, that is to say timed, or after a given number of drying cycles of the machine 1, or even in a controlled manner with sensors.

Let us consider for instance the measurement of load losses in the drying air circuit 20; said measurement can be performed by means of suitable pressure sensors or by measuring the trends in electrical power consumption of the electrical motor actuating the fan 23.

Power consumption reaching preset levels indicates that the filter is clogged and filaments that have built up on the filter, have to be removed.

Alternatively, the filter 26 conditions can be monitored by means of optical sensors: the presence of filaments deposits on the filter prevents light signals from passing through it, which condition can be detected through optical sensors so that a cleaning cycle is started according to what explained right hereabove.

Of course other variants of the invention different from the one described above are also possible.

Indeed, even though the example shown in previous drawings is structurally and functionally simple thus being preferable in that it is economically advantageous, different solutions to be implemented concerning the nozzles or their supply system cannot be ruled out.

For example, indicatively nozzles could be provided that are supplied separately and which spray water only on filter areas set in advance, as they turn out to be clogged.

Another possible variant of the washing/drying machine 1 is shown in figures 7 and 8; according to said variant, in addition to the cleaning device 30 for the filter 26, the washing/drying machine 1 is also equipped with a system to hold filaments within the washing/drying chamber 10.

To this aim, the inner walls of the chamber 10, and in particular at least a portion of the side wall 15 of the chamber 10 have a surface finish that is rough or otherwise jagged, rugged or the like.

Said finish can be obtained by means of any processing that is fit for said purpose, be it mechanical or of a different nature (e.g. chemical, electrical, electrochemical processing) , with or without material removal, performed manually or by means of machining tools suitable for the purpose.

Some examples of suitable processing are hereby provided: knurling (with or without chip removal), lapping, grinding, milling, moulding, abrasion, electrical discharge machining and so forth; they can be employed depending on the material used for the wall 15 of the tub 10, on its thickness, on the type of surface to be treated and other manufacturing-related factors e.g. costs, time, etc.

Advantageously, said surface finish is obtained on the piece together with the rest of the tub wall where it is found, through one single moulding operation.

Figure 8 shows some examples of possible surface finish for the wall 15 obtained, respectively, by means of moulding, knurling and grinding; also the asperities 40, are differently profiled (wavy, saw-tooth, conical) . It is wurth to emphasive that said finish can follow a regular or irregular pattern.

Usually, the wall 15 of the tub 10 is made of a plastic material, or, alternatively, of stainless steel, with a thickness that may range from 1.8 to 2.5-3 mm; the rough surface of the side wall 15 has, preferably, asperities (40) whose height is less than 50% - preferably between 10 % and 40 %- of the washing/drying tub's 11 wall 15 thickness. Therefore, the aforementioned thickness range will produce asperities whose height is less than 1 mm, , preferably between 0.2 e 0.8 mm; under these circumstances, it has however to be noted that also the back wall 16, especially the portion thereby surrounding the filter 26 and /or the collar 17 of the washing/drying chamber 10, may have a rough surface finish according to the explanation provided hereabove .

Even though preferable, whereas not necessary, the surface finish of the back wall 16 and collar 17 may differ from that of the cylindrical side wall 15, depending on various factors such as the size and shape of the washing/drying chamber 10, the configuration of the air circuit i.e. the suction and supply lines 22, 21, the fan 23 etc the filter (26) characteristics and so on.

Regardless of the above, the washing/drying machine 1 described hitherto works as follows.

For drying the laundry, the activation of the fan 23 generates an air flow that is sucked into the chamber 10 by the suction line 21 and then sent back to the same chamber 10 through the supply line 22; as it travels outside the chamber, air is dehumidified within the condenser 21 and possibly heated up with heating means (e.g. by means of an electrical resistance placed in the supply line 22), not shown in the picture as they are known in the art.

Inside the chamber 10 the air flow generated by the fan 23 in addition to removing moisture from the laundry and garments loaded, also removes different fibers and filaments: however, differently than in prior art, these are held by the superficial asperities 40 of the cylindrical side wall 15 of the chamber 10 and, possibly, of the back wall 16 and collar 17.

Consequently, when the air flow directed towards the external circuit 20 reaches the filter 26, it carries a reduced amount of filaments given that these have been held upstream by the walls of the washing/drying chamber 10.

The filter 26 thus only effects a more accurate removal of the residual filaments in the air flow, so that there is no risk of clogging by fluff or larger limit formations, as is the case with known washing/drying machines.

This reduces, therefore, load pressure losses generated by the filter, provides for air circulation and consequently increases the overall efficiency of the entire drying cycle. Filaments held by the wall 15,16 and 17 of the washing/drying chamber 10 are then easily removed by supplying water to the same chamber: this can preferably be done at the beginning of the following washing cycle of the machine 1.

These explanations make it possible to understand that the machine overcomes the technical problem underlying the invention .

Indeed the ability to hold filaments with means that are different from the conventional filters set in the drying air circuit, avoids or at least reduces the risk of clogging that filters are usually subjected to.

This result is achieved thanks to the rough aspect given to the washing/drying chamber 10 with no need for further special additional devices that may present with a drawback in that they would make the machine 1 more complex.

Of course, further variants of the invention different than the second embodiment just considered are possible. As already mentioned, it is possible to have a rough surface finish not only on the cylindrical side wall 15, but also on the back wall 16 and/or on the collar 17 of the chamber 10; it has, however, to be considered that the principle whereby filaments can be held using the surface finish of portions of the washing/drying machine, can be extended to other portions of the same machine.

For instance, this principle could be applied to the external wall of the basket 11; that is to say, let us consider the creation of a rough surface finish, according to the explanations provided above, on the basket's external surface: this way the filaments would be held by that, too, in addition to being held by the washing chamber, so as to improve the results achieved by said washing chamber.

Other variants can be obtained using air circuits 20 that are more complex than that in the case shown in the drawings. At any rate, all these variants fall within the scope of the following claims.

Claims

1. Washing/drying machine comprising a washing/drying chamber (10), a circuit (20, 21, 22, 23) for circulating air taken from the chamber (10) and reintroduced therein, filtering means (26) for filtering the air along the circuit (20-23) , characterized in that it comprises a device (30) for cleaning the filtering means (26) with water.

2. Machine according to claim 1, wherein the cleaning device (30) is arranged in the air circulation circuit (20, 21, 22, 23) and sprays water against the filtering means (26) .

3. Machine according to claims 1 or 2, wherein the filtering means (26) are arranged on a wall (16) of the washing/drying chamber (10) , and the cleaning device (30) comprises a plurality of nozzles (31) external to the chamber (10) , which are adapted to spray liquid against the filtering means (26) .

4. Machine according to any one of the preceding claims, wherein the cleaning device (30) comprises a branch (36) for recirculating water exiting the tub (10), connected to the circuit that supplies water to spray nozzles (31) for spraying water against the filtering means (26) .

5. Machine according to any one of the preceding claims, wherein the nozzles (31) are arranged in a header (32) supplied with mains water or with water recirculated from the tub (10) .

6. Machine according to any one of the preceding claims, wherein the cleaning device (30) is activated when the load loss values detected through the filtering means (26) exceed a preset level.

7. Machine according to any one of the preceding claims, wherein the activation of the cleaning device (30) is timed .

8. Machine according to any one of the preceding claims, comprising surface means (11, 15, 16, 17, 40) for holding the filaments removed from the laundry and borne by the air, which means are arranged along the air path comprising the chamber (10) and the circuit (20-23) .

9. Machine according to claim 8, wherein the means for holding the filaments comprise at least one rough surface portion (15, 16, 17, 40) .

10. Machine according to claim 9, wherein the rough surface portion is obtained on at least one wall (15, 16, 17) of the washing/drying chamber (10) .

11. Machine according to claim 10, wherein the side wall (15) of the chamber has a roughness with asperities (40) smaller than 50%, preferably between 10% and 40%, of the thickness of the side wall.

12. Machine according to any one of claims 8 to 11, comprising a drum (11) for loading laundry to be treated, housed in said chamber (10) , wherein the outer surface of the drum (11) for loading laundry comprises a rough surface portion.

13. Machine according to any one of claims 8 to 12, wherein the means for holding the filaments comprise a rough surface portion (11, 15, 16, 17) with asperities smaller than 0.8 mm.

14. Machine according to any one of claims 8 to 13, comprising an operating step wherein the filaments held by said surface means (11, 15, 16, 17, 40) are removed by the cleaning device (30) .

15. Machine according to any one of the preceding claims, wherein the cleaning device (30) is activated, preferably in a pulsed manner, upon detecting a predetermined relative humidity value in said chamber (10) , said predetermined humidity value being in particular equal to 10%.