WO2015159173A1

WO2015159173A1 - Method for cleaning an air filter in a washing/drying machine and machine for its execution

Info

Publication number: WO2015159173A1
Application number: PCT/IB2015/052393
Authority: WO
Inventors: Giovanni Bombardieri; Lorenzo Verdini; Gianluca Ferro
Original assignee: Indesit Company S.P.A.
Priority date: 2014-04-17
Filing date: 2015-04-01
Publication date: 2015-10-22
Also published as: EP3132081A1; EP3132081B1

Abstract

The invention relates to a method for cleaning the air filter (26) of a washing/drying machine (1) for preventing it from getting clogged by filaments released by the laundry during the drying cycle. The method provides for a step that follows the spinning step for drying the load, wherein the basket (11) is rotated in order to generate an air flow for removing the filaments. The invention further comprises a washing/drying machine implementing the method.

Description

"Method for cleaning an air filter in a washing/drying machine and machine for its execution"

DE SCRI PT ION

The present invention relates to a washing/drying machine, that is to say machines for household, industrial or commercial uses intended for washing and drying laundry in general.

These machines, therefore, have some elements in common with washing machines, such as, for example, the washing tub that houses a rotary basket or drum; the clothing or laundry to be treated is loaded into the basket through a door, which may be located at the front or at the top, depending on the machine type.

The rotation of the basket keeps the load moving during the washing and/or drying phases, when the tub is supplied with water and air, respectively. In the course of the working cycle of the washing/drying machine, the load, consisting of clothing, laundry and the like, normally releases filaments that are evacuated through the drain. This occurs in a simple and direct manner during the wash, in that water is supplied and drained several times for washing, rinsing, etc., so that the filaments released by the fabrics are removed from the laundry and evacuated together with the water being drained.

When the laundry is dried, instead, the filamentous fluffs that are dragged by the air flow circulating in the machine and lapping the clothes contained in the basket for drying them, cannot be drained in the same way because the air flows within a closed circuit and goes through all of the elements that make up the air cooling, heating and pressurizing system (usually a motorized fan) . As can be easily understood, the air flow needs to be cyclically filtered to avoid that the filamentous fluffs might accumulate and obstruct the air flow in the circuit.

To this end, it is known to take air from the washing and drying tub, to cool it in an exchanger to condense the moisture removed from the laundry, to filter it, and then to supply it again into the tub after heating.

The air is filtered as it flows through a grid made of metal, plastic or the like, arranged on a wall of the washing/drying chamber, the mesh of which is sufficiently tight to trap the filaments released by the fabrics; it can be easily understood that the filamentous fluffs progressively depositing onto the filter will reduce the air passage section thereof and will cause pressure head losses that will slow down the air flow, resulting in a general reduction of the efficiency of the laundry drying cycle.

The present invention aims at overcoming these^' problems that affect the state of the art.

Therefore, the technical problem underlying the invention is to provide a method for cleaning the air filter of a washing/drying machine in a simple and effective manner, such that it can also be carried out on existing wa s h i ng / dry i ng machines or anyway without requiring significant modifications to the machines and/or to their operating cycle. The idea for solving this problem is to exploit the basket of the washing/drying machine to generate an air flow inside the tub, which allows removing the filaments deposited on the filter grid: in this way it is possible to prevent the filter from getting clogged quickly, thereby keeping it efficient and reducing pressure head losses for a longer time.

For this reason, the method of the invention envisages an , operating step of the washing/drying machine wherein the basket is rotated for cleaning the filter .

The features of the method of the invention will be specifically set out in the claims appended to this description; in this regard, it must be pointed out that the invention comprises also a wa s h i ng / dr y i ng machine implementing the filter cleaning method, whose features are also set out in the appended claims .

Such features will become more apparent from the following description of a preferred but non- limiting embodiment as schematically shown in the annexed drawings, wherein:

- Fig. 1 is a perspective view of a wa s h i ng / dr y i ng machine according to the invention;

- Fig. 2 is a perspective view of the washing/drying tub of the machine of Fig. 1;

Fig. 3 is a perspective view of the washing/drying tub of the machine of Fig. 1, from a different angle than Fig. 2; - Fig. 4 shows the tub of Figures 2 and 3 with a part thereof removed to make the internal parts visible;

- Fig. 5 shows the tub of Figures 2 and 3 with a part thereof removed to make the inner wall visible;

Fig. 6 shows the basket of the wa sh i ng / dr y i ng machines of the preceding figures, from a different viewpoint;

- Fig. 7 shows some examples of a mesh of the air filter of the washing/drying . machine of the preceding figures.

With reference to the above-listed drawings, reference numeral 1 designates as a whole a washing/drying machine in accordance with the present invention, which comprises an external structure 2 substantially shaped like a parallelepiped cabinet, with a front panel 3 equipped with user controls (e.g. push-buttons, knobs, etc.) and various indicators, lights, displays, or other means such as detergent drawers, useful for the control and operation of the machine 1.

It is worth pointing out that reference will be made in this description, for simplicity and clarity, only to those elements of the washing/drying machine 1 which are useful for understanding the invention; for more information, reference can be made to the prior art, e.g. washing/drying machines created by the present Applicant or described in patent applications filed by the latter on this matter, such as European patent applications EP 2116647, EP 2281081, EP 1907616, EP 1775368, EP 1647621, and more, which are integrally recalled herein, and whose contents should be considered as incorporated in the present description, as applicable thereto.

At the front of the structure 2 there is the load opening 4 of the washing/drying machine, which is closed by a door 5.

The structure 2 of the wa s h i ng / dr yi ng machine internally houses a washing/drying chamber or tub 10, in which a basket 11 for loading laundry to be treated is supported in a per se known manner. The chamber or tub 10 is intended for washing/drying laundry, in that a machine like the one considered herein performs a dual function as a water tub during the washing cycle and as a drying chamber during the drying cycle.

The basket 11 has the typical drum-like configuration, with a perforated wall allowing water to flow through, as visible in Figures 1 and 4, and is equipped with inner ribs or lifters 12 for stirring the load while rotating when the machine l is in operation.

Externally, the basket 11 has, on its back wall 13, a series of protruding fins 14; advantageously, such fins can be formed on the spider 6 that stiffens the basket 11 and connects it to its drive shaft 7.

The fins 14 may have different shapes, depending on the configuration and dimensions of the basket 11 and of the washing chamber.

Preferably they extend, at least partly, radially relative to the axis of rotation of the basket, which in this case coincides with the shaft 7; preferably, the fins 11 has an aerodynamic shape that allows them to provide a "helix" effect, by means of which they can impart a thrust upon the air that is present in the washing chamber 10.

The fins 11 may be advantageously configured like the blades of an impeller of a fan, whether axial or radial, so as to impart on the air in the washing chamber 10 a speed that is useful for implementing the method of the invention, as will be further described below.

The chamber 10 comprises a substantially cylindrical skirt or side wall 15 (possibly slightly convex), closed at the rear by a back wall 16, while at the front it has a collar 17 on which a gasket 18 is applied, sealing the opening 4 of the cabinet 12 of the washing/drying machine 1.

Outside the washing/drying chamber 10 a drying air circuit 20 is arranged, which comprises an intake channel 21 and a delivery channel 22, between which a fan 23 is arranged for air circulation. In particular, the intake channel 21 extends from the collar 17 of the chamber 10 to the fan 23, whereas the delivery channel 22 extends from the fan 23 to an intake port formed in the back wall 16 of the chamber 10, where a filter 26 is arranged .

The latter is slightly eccentric relative to the axis of rotation of the basket 11, where the support and/or rotation means of the basket 11, such as shaft, bearings, pulleys, etc. (not shown in the drawings because they are per se known) are applied to the back wall 16 of the chamber 10.

The filter 26 may be designed in any appropriate manner, e.g. with a metal or plastic grid having a mesh suitable for trapping the filaments released by the laundry being treated in the washing/dr.ying machine 1; the mesh may have a polygonal (e.g. square, rectangular, hexagonal) or circular geometry, etc., the mesh size being in the range of 2-8 mm2.

Figure 7 shows some examples of mesh that can be used for making the filter 26.

The wall 15 of the tub 10 is usually made of plastics, with a thickness that may vary from 1.8 to 2.5-3 mm .

The operation of the washing/drying machine 1 described so far is as follows; also in the operation description reference will be made only to those operating steps which are useful for understanding the invention, and for further information reference should be made to prior-art machines . In order to dry the laundry, the fan 23 is activated and produces an air flow that is taken from the chamber 10 through the channel 21 and is then reintroduced into the same chamber 10 by means of the delivery channel 22; along its path outside the chamber, the air is dehumidified, by exchanging heat with a condenser, and possibly heated by heating means (e.g. electric resistors) , which are not shown in the drawings because they are known in the art.

In the chamber 10, the air flow generated by the fan 23, in addition to removing humidity from the load of laundry and various clothing, also removes the various fibers and filaments trapped in the filter 26.

Therefore, this increases the pressure head losses caused by the filter, countering air circulation and, consequently, impairing the efficiency of the drying cycle .

In order to prevent this situation from occurring, the filter 26 can be cleaned by rotating the basket 11, which, thanks to the fins 14 provided thereon, will generate an air blast in the washing chamber 10 to remove the filaments deposited on the grid of the filter 26.

In this respect, it must be pointed out that, depending on the configuration of the fins 14 and/or of the direction of rotation of the basket (clockwise or counterclockwise) , cleaning can be attained by blowing an air flow onto the filter or by creating a slight vacuum in the washing chamber 10, so as to remove the filaments trapped in the filter grid.

Ih fact, the shape of the fins may promote either situation, depending on the direction of rotation of the basket 11.

Preferably, in accordance with the invention, the operation of the washing/drying machine 1 includes a cycle for cleaning the filter 26 at the end of the laundry spinning step, which is carried out by turning the basket at high speed ( indica^'t i ve 1 y more than 90 rpm) at any time starting from moment when the load has reached a drying level of less than 20% until the beginning of the next washing cycle, so that the subsequent drying cycle will be carried out with a clean filter.

The cleaning cycle is executed by turning the basket 11 as explained above; even if the laundry is still in there, they will not release any water because they have already been spun.

It can however be understood that the cleaning can be carried out at any time in a controlled manner depending on various options; for example, it may be envisaged that the filter 26 should be cleaned at the end of every laundry drying cycle.

This option offers the advantage that, when the washing/drying machine is used again, it will rinse and then drain the washing chamber 10 to evacuate the filaments removed from the filter 26 during the cleaning cycle.

As an alternative to or in combination with this option, the cleaning of the filter 26 may be carried out as a function of the operating condition of the filter.

This is the case wherein the washing/drying machine 1 is equipped with means for detecting pressure losses in the filter 26; such means may be either of the direct type, such as pressure sensors arranged upstream and/or downstream of the filter and detecting the pressure of the drying air, or of the indirect type, i.e. indicating the filter condition on the basis of the electric energy consumption of the fan 23.

In fact, when pressure losses increase due to a clogged filter 26, the fan will require more power to keep the drying air flow constant.

It can be easily understood from the above description how the method for cleaning the filter in the washing/drying machine 1 can solve the technical problem addressed by the invention.

In fact, the latter teaches to exploit the rotation of the basket 11 in order to generate an air blast inside the washing chamber 10, which allows removing the filaments trapped in the filter grid.

^■This teaching can be implemented in the way explained in detail above, but also by adopting alternative solutions.

First of all, it is understandable that the shape, dimensions, number and arrangement of the fins 14 may be different from what is shown in the annexed drawings; in this regard, it must be pointed out that the fins may be arranged on the cylindrical skirt of the basket instead of, or in addition to, the back wall 13.

It should also be clarified t.hat the fins 14 may even be absent, as is the case when the rotation of the basket 11 can per se generate the air blast in the washing chamber 10, which is required for cleaning the filter 26 as previously explained. Among other things, this will depend on the shape and size of the washing chamber 10 and/or of the basket 11.; also the adopted basket rotation can contribute to this purpose.

In a preferred embodiment of the invention, in fact, the direction of rotation of the basket 11 for cleaning the filter 26 is opposite to the one used for spinning the laundry: by exploiting this condition, it is possible to obtain an improved filter cleaning effect, since the air is moved from the basket 11 to the washing chamber in an opposite manner.

In this frame, it must be pointed out that the revolution speed of the basket 11 for cleaning the filter may depend on various parameters, such as, for example, the shape, dimensions and number of the fins 14, the duration of the cleaning cycle, the degree of clogging of the filter. The latter can be detected, as aforesaid, as a function of various operating parameters, whether direct or indirect, of the washing/drying machine.

The speed of the basket is anyway preferably high, close to that of the laundry spinning cycle.

All of these variants will still fall within the scope of the following claims.

Claims

1. Method for cleaning an air filter (26) in a washing/drying machine (1) comprising a washing/drying chamber (10), a basket (11) for loading laundry, housed in said chamber (10), characterized in that it comprises at least one operating step wherein the basket (11) is rotated in order to generate an air displacement in the washing chamber (10) , so as to remove any fibers, filaments or similar elements trapped in the filter (26) .

2. Method according to claim 1, wherein said operating step is carried out after the spinning step.

3. Method according to claim 1 or 2, wherein said operating step is carried out after the drying step.

4. Method according to any one of the preceding claims, wherein the direction of rotation of the basket (11) during said operating cleaning step is opposite to the spinning direction.

5. Washing/drying machine comprising a washing/drying chamber (10), a rotary basket (11) for loading laundry housed in said chamber (10), a circuit (20, 21, 22, 23) for circulating air taken in from the chamber (10) and then reintroduced therein, a filter (26) for filtering the air along the circuit (20-23), characterized in that it comprises means (14) associated with the basket (11) for generating an air displacement in the washing chamber (10), so as to remove any fibers, filaments or similar elements trapped in the filter (26) .

6. Machine according to claim 5, wherein the means associated with the basket (11) comprise at least one fin (14) protruding therefrom, which, upon rotation of the basket (11), produces an air blast towards the filter (26) .

7. Machine according to claim 6, wherein said at least one fin (14) is arranged on a back wall (13) of the basket .

8. Machine according to claim 7, wherein said at least one fin (14) is formed on a stiffening spider (6) of the basket ( 11 ) .

9. Machine according to any one of claims 5 to 8, wherein the means associated with the basket (11) for generating the air displacement are adapted to rotate it after the spinning and/or drying steps.

10. Machine according to claim 9, wherein the direction of rotation of the basket (11) after the spinning and/or drying steps is opposite to the spinning and/or drying direction.