EP3693506A1

EP3693506A1 - Laundry dryer and fluff trap

Info

Publication number: EP3693506A1
Application number: EP20154493.9A
Authority: EP
Inventors: Fabio Roncati; Paolo MANTICA
Original assignee: Candy SpA
Current assignee: Candy SpA
Priority date: 2019-02-08
Filing date: 2020-01-30
Publication date: 2020-08-12
Anticipated expiration: 2040-01-30
Also published as: EP3693506B1; IT201900001819A1

Abstract

A laundry dryer (1) comprises a housing (2) which houses a laundry compartment (3), an air circuit (4) which includes the laundry compartment (3) and a heat exchanger (5) for extracting moisture from the drying air (11), a fluff trap (6) positioned in the air circuit (4) downstream of the laundry compartment (3) and upstream of the heat exchanger (5), wherein the fluff trap (8) comprises a filter support structure (10), a sieve-filter wall (9) supported by the filter support structure (10) and a filter cleaning system (11), wherein the filter cleaning system (11) comprises:- one or more spray nozzles (12) supported by the filter support structure (10) and configured to spray one or more pressurized water jets (13) on the filter wall (9) to soak and detach fluff (14) from the filter wall (9), and- a scraping member (15) supported by the filter support structure (10) in a scraping position against the filter wall (9),- a filter movement device (16) configured to move the filter wall (9) with respect to the filter support structure (10) and with respect to the scraping member (15) so that the scraping member (15) brushes the soaked fluff (14) away from the filter wall (9).

Description

The present invention relates to a laundry dryer or combo washer dryer which provides for drying laundry by means of a drying air flow, in which the moist drying air from the laundry compartment passes through a fluff trap before entering into a heat exchanger for the moisture extraction by means of condensation.
In a closed drying circuit with an electrical resistor or a heat pump, the warm and dry drying air is conveyed into the laundry compartment, in particular a basket or drum, where, by passing through the wet laundry, it causes the evaporation of the water contained in the fabrics. After exiting the laundry compartment, the drying air loaded with moisture passes through a heat exchanger where it is cooled down, in order to extract the moisture therefrom by means of condensation. The dehumidified drying air is then sucked in again by the ventilator, heated and routed into the laundry compartment.
Upstream of the heat exchanger (where the moisture extraction occurs) a fluff trap is arranged to protect the heat exchanger from pollution and sedimentation of substances extracted from the laundry together with the moisture, for example hair, fabric fibers, detergent residues, which would otherwise reduce the heat exchange efficiency and therefore the performance of the dryer.
In the case of a laundry dryer with a heat pump, the fluff trap is arranged upstream of the cooling heat exchanger (embodied by the heat pump evaporator) to protect both the latter and a subsequent heating heat exchanger (embodied by the condenser of the heat pump) from pollution and sedimentation of substances extracted from the laundry together with the moisture, for example hair, fabric fibers, detergent residues, which would otherwise reduce the heat exchange efficiency and therefore the performance of the dryer.
The additional fluff traps must be regularly extracted from the laundry dryer and cleaned by the user (usually after each drying cycle). The positioning of the fluff traps in the lower part of the laundry dryer and the need to first open the base and extract and re-insert the fluff trap in a leaning posture create discomfort for the user.
Automatic fluff trap cleaning systems in laundry dryers are known, in which a flow of condensed water is allowed to flow along the fluff trap to soak and remove the fluff from the filter wall.
Automatic fluff trap cleaning systems in laundry dryers are also known, in which a movable scraping member is allowed to slide along a stationary filter wall to scrape away the fluff deposits.
The filtering systems of the background art and in particular the cleaning methods thereof are not yet satisfactory and it is desirable to have self-cleaning or partially self-cleaning fluff traps for laundry dryers, having features such as to obviate the need for frequent extractions, cleaning and re-insertions of the fluff trap into the household appliance.
This and other objects are achieved by a fluff trap and by a laundry dryer according to the appended claims.
According to an aspect of the invention, a laundry dryer comprises a housing which houses a laundry compartment, in particular a rotatable drum or basket, a drying air circuit which includes the laundry compartment, a heat exchanger for extracting moisture from the drying air, as well as a fluff trap positioned in the drying air circuit downstream of the laundry compartment and upstream of the heat exchanger, in which the fluff trap comprises a filter support structure, a sieve-filter wall supported by the filter support structure and a filter cleaning system configured to brush and/or scrape the fluff trap sieve-filter wall mounted in the laundry dryer,
characterized in that the filter cleaning system comprises:

one or more spray nozzles supported by the filter support structure and configured to spray one or more pressurized water jets on the filter wall to soak and detach fluff from the filter wall, and
a scraping member supported by the filter support structure in a scraping abutment against the filter wall,
a filter movement device configured to move the filter wall with respect to the filter support structure and with respect to the scraping member so as to brush the soaked fluff away from the filter wall.

By virtue of the combined effect of pressurized water jets and mechanical brushing, when moving the filter wall with respect to the scraping or brushing member:

it is not necessary to remove and clean the fluff trap manually at each drying cycle,
the mechanical and soaking effect of pressurized water provides a "prewash" of the filter wall, while the mechanical brushing removes fluff residues from the filter wall.
it is not necessary to perform movements or significant movements with the scraping member which solidly involves considerable space problems in the fluff trap area,
a movement of the filter wall, for example, in the development plane thereof along the scraping member (and not vice versa), does not require significant additional space and allows to perform a scraping or a brushing in the presence of a stationary or substantially stationary reaction support of the filter wall, which ensures a more reliable scraping pressure and avoids undesired deformations of the filter wall under the action of the scraping member.
by moving the filter wall with respect to the scraping member (and not vice versa) it is also easier to collect and control the further handling and transport of the fluff brushed away from the filter wall at the scraping member.

According to a further aspect of the invention, the laundry dryer comprises an electronic control system, which can be programmed by the user to select or set respectively one of a plurality of drying cycles, and is configured to automatically activate the filter cleaning system, for example, according to the execution of the drying cycles.
To better understand the invention and appreciate the advantages thereof, a number of non-limiting embodiments will be described below, with reference to the drawings, in which:

Figure 1 shows a diagrammatic representation of a closed drying circuit with a heat pump, implemented in a laundry washing machine or combo washer dryer in accordance with the invention;
Figure 2 shows a diagrammatic representation of a closed drying circuit with an electrical resistor, implemented in a laundry washing machine or combo washer dryer in accordance with the invention;
Figure 3 shows a diagrammatic side view, according to a vertical section plane, of the laundry dryer with the indication of the drying air flow;
Figure 4 shows a diagrammatic top view according to a horizontal section plane, of the laundry dryer in Figure 3 with the indication of the drying air flow (continuous arrows) and of a cooling air flow (dashed arrows);
Figure 5 shows a side view of a self-cleaning fluff trap according to an embodiment;
Figure 6 shows a front view of the self-cleaning fluff trap in Figure 5;
Figure 7 shows an enlarged view of a detail in Figure 5,
Figure 8 shows a diagrammatic view of a self-cleaning fluff trap according to a further embodiment.

With reference to Figures 1 to 4 , a laundry dryer 1 comprises a housing 2 which houses a laundry compartment 3, in particular a drum or basket rotatable by means of a motor 4, an air circuit 5 for the drying air 6 which includes the laundry compartment 3, a heat exchanger 7 for extracting moisture from the drying air 6, as well as a fluff trap 8 positioned in the air circuit 5 downstream of the laundry compartment 3 and upstream of the heat exchanger 7.
In accordance with the invention, the fluff trap 8 comprises a filter support structure 10, a sieve-filter wall 9 supported by the filter support structure 10 and a filter cleaning system 11 configured to brush and/or scrape the filter wall 9 (with the fluff trap 8 mounted in the laundry dryer 1).
The filter cleaning system 11 comprises:

one or more spray nozzles 12 supported by the filter support structure 10 and configured to spray one or more pressurized water jets 13 on the filter wall 9 to soak and detach fluff 14 from the filter wall 9, and
a scraping member 15 supported by the filter support structure 10 in a scraping position against the filter wall 9,
a filter movement device 16 configured to move the filter wall 9 with respect to the filter support structure 10 and with respect to the scraping member 15 so that the scraping member 15 brushes the soaked fluff 14 away from the filter wall 9.

By virtue of the combined effect of the pressurized water jets 13 and mechanical brushing, when moving the filter wall 9 with respect to the scraping member 15:

it is not necessary to remove and clean the fluff trap 8 manually at each drying cycle,
the mechanical and soaking effect of pressurized water provides a "prewash" of the filter wall 9, while the mechanical brushing removes fluff 14 residues from the filter wall 9,
it is not necessary to perform movements or significant movements with the scraping member 15 which would otherwise involve considerable space problems in the fluff trap area,
a movement of the filter wall 9, for example, in the development plane thereof along the scraping member 15 (and not vice versa), does not require significant additional space and allows to perform a scraping or a brushing in the presence of a stationary or substantially stationary reaction support of the filter wall 9, which ensures a more reliable scraping pressure and avoids undesired deformations of the filter wall 9 under the action of the scraping member 15.
by moving the filter wall 9 with respect to the scraping member 15 (and not vice versa) it is also easier to collect and control the further handling and transport of the fluff 14 brushed away from the filter wall 9 at the scraping member 15, which can be stationary or substantially stationary.

In accordance with an embodiment, the filter support structure 10 can comprise a filter housing, for example a frame or a grille made of plastic or metal material.
The filter housing may form an inlet opening 17 for the inlet of the air flow 6 coming from the laundry compartment 3, as well as one or more outlet openings 18 for the outlet of the air 6 after the filtering.
the filter support structure 10 or the filter housing supports the filter wall 9, for example at the inside thereof, so that an inlet surface 19 of the filter wall 9 faces against the direction of the flow of drying air 6 or, in other words, towards the inlet opening 17, and an opposite outlet surface 20 of the filter wall 9 faces in the direction of the flow of air 6 or, in other words, towards the outlet opening 18. Thereby, the fluff transported by the air flow 6 is deposited on the inlet surface 19 of the filter wall 9.
The filter wall 9 may consist of a mesh or a fabric made of a synthetic polymeric material, possibly reinforced with glass or carbon fibers or, alternatively, of a metal material, or of a perforated sheet of a synthetic or metal material. The fluff trap 8 is preferably positioned in a front area of the laundry dryer 1, below the laundry compartment 3.
According to one embodiment, the movement device 16 comprises one or more, preferably two but possibly three or more, spools 21 or drums, at least one, more or all of which can be actuated in rotation, for example, by means of one or more electric motors 22. The filter wall 9 is supported by said spools 21, for example wound about, or supported by and/or returned on, one or more of said spools 21, so that the rotary actuation of the one or more spools 21 moves the filter wall 9 in scraping or brushing contact against the scraping member 15.
According to an advantageous embodiment, the movement device 16 comprises two spools 21 spaced apart from each other, which can be actuated in rotation by means of a single electric motor 22. The filter wall 9 is supported by said spools 21, so that:

the rotary actuation of the two spools 21 in a first rotational direction 23 unwinds the filter wall 9 from a first spool 21' of the two spools 21 and winds the filter wall 9 on a second spool 21" of the two spools 21, keeping the filter wall 9 pulled/pull-tensioned between the first spool 21' and the second spool 21" and always in scraping or brushing contact against the scraping member 15,
the rotary actuation of the two spools 21 in a second rotational direction 24 unwinds the filter wall 9 from the second spool 21" of the two spools 21 and winds the filter wall 9 on the first spool 21' of the two spools 21, keeping the filter wall 9 pull-tensioned between the first spool 21' and the second spool 21" and possibly always in scraping or brushing contact against the scraping member 15.

Advantageously, the first spool 21' is arranged higher than, preferably vertically above, the second spool 21', so as to keep the filter wall 9 pull-tensioned in a vertical or at least approximately erected filtering plane 25 between said first 21' and second 21" spools.
The electric motor 22 can be coupled to a synchronization or differential transmission 26 which transmits the motion, in a planned manner, to the spools 21, 21', 21'.
Advantageously, the filter wall 9 is supported and pull-tensioned by the one or more spools 21, 21', 21" so as to be extending along an extension path 27 between end paths 28, in which, during the movement of the filter wall 9 in scraping contact against the scraping member 15, the extension path 27 remains substantially unchanged and at least one or more of the end paths 28 undergo a variation of the winding length.
The invariability of the extension path 27 saves space and allows an easier washing of the filter wall by means of the spray nozzles 12.
According to an embodiment, the scraping member 15 comprises one or more scrapers or brushes:

stationary, or
movable by means of a scraper actuator 29 thereof, for example, an electric motor, or
movable by means of the same actuator (motor 22) of the filter movement device 16,

inlet surface

filter wall

fluff

According to one embodiment, the fluff trap 8 forms a reaction surface 30 arranged at the scraping member 15, but on the side of the filter wall 9 opposite with respect to the side (inlet surface 19) on which the scraping member 15 acts, so as to form an abutment for the thrust of the scraping member against the filter wall 9 and avoid undesirable deformations of the latter.
According to one embodiment, the reaction surface 30 is formed by one of the spools 21 or by a portion of a filter wall wound on one of the spools 21.
According to an alternative embodiment, the reaction surface 30 is formed at a distance from the spool or spools 21.
According to a preferred embodiment, the scraping member 15 is kept in contact against the filter wall 9 at one of the spools 21, preferably at the aforesaid second (lower) spool 21".
Advantageously, the scraping member 15 is positioned below (preferably vertically below) the aforesaid second (lower) spool 21" and in contact from below against the filter wall 9.
According to one embodiment, the scraping member 15 comprises a linear brush extending in a direction transverse with respect to the movement direction of the filter wall 9 and/or extending parallel to the rotation axis of the spool 21 with which it is associated.
According to one embodiment, the scraping member 15 can be moved in a direction transverse with respect to the movement direction of the filter wall 9 and/or parallel to the rotation axis of the spool 21 with which it is associated. Thereby a bi-directional brushing effect is obtained.
According to an embodiment, the scraping member 15 can be moved in rotation and in contact with (the inlet surface 19 of) the filter wall 9, in particular, in rotation in the same direction of rotation of the spool 21 to which it is associated. Thereby the relative brushing speed between the scraping element 15 and the filter wall 9 increases.
According to one embodiment, the spray nozzles 12 are connected to a water supply system 31 which supplies mains water and/or washing water from a suitable water tank 32 and/or water condensed from the drying air flow 6.
According to one embodiment, the spray nozzles 12 are positioned in an upper part of the fluff trap 8 and spray from the top downwards against (the inlet surface 19 of) the filter wall 9.
The spray nozzles 12 direct pressurized water jets onto the (inlet surface 19 of) the filter wall 9, preferably at an impact angle 39 lower than 60°, preferably lower than 45° with respect to the plane of the filter wall 9 at the point of impact of the water jet.
Advantageously, the area in which the pressurized water jets impact on the filter wall 9 is arranged in an area in which the filter wall is free from supports, preferably in an area between two spools 21, 21', 21".
With a further advantage, the spray nozzles 12 direct the water jets substantially in the movement direction of the filter wall 9 and/or downwards. This facilitates the collection of water sprayed together with the fluff detached from the filter wall 9 in a lower area of the fluff trap 1.
The spray nozzles 12 can be stationary or can be actuated in movement, e.g., they can perform:

an alternating movement of the nozzle itself in a direction transverse with respect to the movement direction of the filter wall 9, or
an alternating rotary movement of the nozzle which generates an alternating movement of the water jet transverse with respect to the movement direction of the filter wall 9.

For the movement of the spray nozzles 12 a nozzle movement device 40 can be provided, for example, a fluid-dynamic device actuated by the pressure of the water supplied to the spray nozzles 12, or an electric motor, or a transmission which couples and/or synchronizes the movement of the spray nozzles 12 with the movement of the filter wall 9.
The filter cleaning system 11 further comprises a fluff transport system 33 with a fluff collection container 34, arranged below the scraping member 15 and adapted to collect the water sprayed by the spray nozzles 12 and the fluff separated from the filter wall 9, as well as with a transport duct 35, possibly equipped with a transport pump 36, which connects the fluff collection container 34 to a collection tray 37 which can be extracted and emptied by the user.
According to a further aspect of the invention, the laundry dryer 1 comprises an electronic control system 38, which can be programmed by the user to select or set one of a plurality of drying cycles, respectively, and configured to automatically activate the filter cleaning system 11, for example, according to the execution of the drying cycles, for example, after each drying cycle or after a predetermined number of hours of operation of the laundry dryer 1.
During the normal operation of the laundry dryer 1, the filter wall 9 remains stationary in a position, facing the flow of drying air 6, so as to trap the fluff on the surface 19 facing the air flow.
The fluff removal cycle 14, which will be defined within the drying cycle in terms of frequency and duration, consists of a first washing action of the filter wall 9 with the use of water applied by means of the spray nozzles 12 from the top downwards. In conjunction with this operation, a step is added of mechanical removal of the fluff 14 from the filter wall 9, by means of the scraping member 15 (preferably a stationary brush) positioned at a lower area of the filter wall 9 and which collects the fluff 14 remaining on the filter wall 9 which, sliding downwards, conveys such fluff 14 against the scraping member 15.
The fluff that is detached and collected at the scraping member 15 is deposited in the collection container 34 in the lower part of the filtering device 8 and evacuated by means of and together with the water dispensed by the spray nozzles 12.
The invention described so far can be advantageously implemented in laundry dryers with a closed air circuit, with an electrical resistor or with a heat pump.
In the embodiment with a closed drying circuit 5 and with an electrical resistor, the drying air 6 is conveyed by means of a ventilator 41 (activated by a motor 42), is heated by means of an electrical resistor 43 and is routed into the laundry compartment 3, in particular a rotatable basket or drum, where, by passing through the wet laundry, causes the evaporation of the water contained in the fabrics. After exiting the laundry compartment 3, the drying air 6 loaded with moisture passes through the heat exchanger 7, where it is cooled down, for example by means of a flow of cold water or of fresh air 44 conveyed by means of a second ventilator (preferably, but not necessarily, activated by means of the same electric motor 42), in order to extract the moisture therefrom by means of condensation. The condensation is collected in a condensation container which can be extracted, or drained by means of a drain pump and/or together with the cooling water. The dehumidified drying air 6 is then sucked in again by the ventilator 41, heated by means of the electrical resistor 43 and rerouted into the laundry compartment 3.
Upstream of the heat exchanger 7 (where the moisture extraction occurs) the fluff trap 8, with the cleaning system 11 described above, is arranged.
In the embodiment with a closed drying circuit 5 and with a heat pump, after exiting the laundry compartment 3, the drying air 6 loaded with moisture passes through a first (cold) heat exchanger 45 embodied by an evaporator 46 of the heat pump, where the air 6 is cooled down in order to extract the moisture therefrom by means of condensation. Also in this case, the condensation may be collected in a condensation container which can be extracted, or may be drained, e.g., by means of a drain pump. The dehumidified and cooled drying air 6 is then routed into a second (hot) heat exchanger consisting of a condenser 47 of the heat pump, where the air is heated up. The dehumidified and heated air is sucked in by means of a ventilator 41, and routed again into the laundry compartment 3 in order to continue the extraction of the moisture from the laundry.
The heat pump further comprises a compressor 48 which sucks in a refrigerant fluid through the evaporator 46, where the fluid itself evaporates at low pressure (absorbing the heat of the drying air 6), compresses the refrigerant fluid and pushes it inside the condenser 47 where the compressed and heated refrigerant fluid condenses and cools down at high pressure (releasing its heat to the drying air 6). After the condenser 47, the refrigerant fluid passes through a thermal expansion valve 49 which reduces the fluid pressure, with a consequent lowering of the temperature and, subsequently, enters again in the evaporator 46, restarting the cycle.
Even in the embodiment with the heat pump, upstream of the first heat exchanger 45 (evaporator 46) the aforesaid fluff trap 8 with the cleaning system 11 is arranged.
According to an embodiment, to allow the inspection, maintenance and, if necessary, the replacement of the filter wall 9, the fluff trap 8, or only the filter wall 9, may be assembled in the housing 2 in a manner extractable from the laundry dryer 1.
As it is known, the control system 38 is in signal connection with and controls the electrical supply of the individual functional groups of the laundry dryer 1, as diagrammatically shown in Figures 1 and 2 .
The control system 35 may further comprise an optical indicator, e.g., a LED, display, etc. or an acoustic indicator to signal to the user the need to extract the fluff collected in the collection tray 37.

Claims

A laundry dryer (1) comprising a housing (2) which houses:
- a laundry compartment (3),

- an air circuit (5) which includes the laundry compartment (3) and a heat exchanger (7) for extracting moisture from the drying air (6),

- a fluff trap (8) with a sieve-filter wall (9), positioned in the air circuit (5) downstream of the laundry compartment (3) and upstream of the heat exchanger (7),
wherein the fluff trap (8) comprises a filter support structure (10), said sieve-filter wall (9) supported by the filter support structure (10) and a filter cleaning system (11),
wherein the filter cleaning system (11) comprises:
- one or more spray nozzles (12) supported by the filter support structure (10) and configured to spray one or more pressurized water jets (13) on the filter wall (9) to soak and detach fluff (14) from the filter wall (9), and

- a scraping member (15) supported by the filter support structure (10) in a scraping abutment against the filter wall (9),

- a filter movement device (16) configured to move the filter wall (9) with respect to the filter support structure (10) and with respect to the scraping member (15) so that the scraping member (15) brushes the soaked fluff (14) away from the filter wall (9).
A laundry dryer (1) according to claim 1, wherein the movement device (16) comprises one or more spools (21) which can be actuated in rotation by means of one or more electric motors (22) and the filter wall (9) is supported by said one or more spools (21), so that the rotary actuation of the one or more spools (21) moves the filter wall (9) in brushing contact against the scraping member (15).
A laundry dryer (1) according to claim 2, wherein the movement device (16) comprises two spools (21) spaced apart from each other and the filter wall (9) is supported by said two spools (21), so that:
- the rotary actuation of the two spools (21) in a first rotational direction (23) unwinds the filter wall (9) from a first spool (21') of the two spools (21', 21") and winds the filter wall (9) on a second spool (21") of the two spools (21', 21"), keeping a portion of the filter wall (9) extending between the first spool (21') and the second spool (21") and keeping the filter wall (9) always in brushing contact against the scraping member (15),

- the rotary actuation of the two spools (21) in a second rotational direction (24) unwinds the filter wall (9) from the second spool (21") of the two spools (21', 21") and winds the filter wall (9) on the first spool (21') of the two spools (21', 21"), keeping a portion of the filter wall (9) extending between the first spool (21') and the second spool (21"),
wherein, the first spool (21') is arranged vertically above the second spool (21'), so as to keep the filter wall (9) pull-tensioned in a vertical filtering plane (25) between said first (21') and second (21") spools.
A laundry dryer (1) according to claim 2 or 3, wherein the electric motor (22) is coupled to a synchronization or differential transmission (26) which transmits the motion to the spools (21, 21', 21').
A laundry dryer (1) according to one of claims 2 to 4, wherein the filter wall (9) is supported and pull-tensioned by the one or more spools (21, 21', 21") so as to be extending along an extension path (27) between movement end paths (28), wherein during the movement of the filter wall (9) in contact against the scraping member (15), the extension path (27) remains substantially unchanged and at least one of the end paths (28) undergoes a variation of the winding length.
A laundry dryer (1) according to one of the preceding claims, wherein the scraping member (15) comprises one or more scrapers or brushes in contact with the filter wall (9) and:
A) said one or more scrapers or brushes are:
- stationary, or

- movable by means of an own scraper actuator (29), or

- movable by means of the same actuator (22) of the filter movement device (16),

B) the fluff trap (8) forms a reaction surface (30) arranged at the scraping member (15), but on the side of the filter wall (9) opposite with respect to the side on which the scraping member (15) acts, so as to form an abutment for the thrust of the scraping member against the filter wall (9).
A laundry dryer (1) according to claim 6 and 2, wherein the reaction surface (30) is formed by one of the spools (21) or by a portion of filter wall (9) wound on said spool (21).
A laundry dryer (1) according to claim 3, wherein the scraping member (15) is kept in contact against the filter wall (9) at the second lower spool (21").
A laundry dryer (1) according to claim 8, wherein the scraping member (15) is positioned below the second spool (21") and in contact from below against the filter wall (9), with the laundry washing machine (1) in the position of use.
A laundry dryer (1) according to any one of the preceding claims, as dependent on claim 2, wherein the scraping member (15) comprises a linear brush extending parallel to the rotation axis of the spool (21) with which it is associated.
A laundry dryer (1) according to any one of the preceding claims, wherein the scraping member (15) is movable:
- in a direction transverse with respect to the movement direction of the filter wall (9), or

- in rotation and in contact with the filter wall (9).
A laundry dryer (1) according to any one of the preceding claims, wherein:
A) the spray nozzles (12) are positioned in an upper part of the fluff trap (8) and spray from the top downwards against the filter wall (9), and/or

B) the spray nozzles (12) direct water jets at an impact angle (39) lower than 45° with respect to the plane of the filter wall (9) at the point of impact of the water jet,
wherein the area in which the pressurized water jets impact on the filter wall (9) is arranged in a region in which the filter wall (9) is free from supports, and/or

C) the spray nozzles (12) are stationary.
A laundry dryer (1) according to any one of claims 1 to 12, wherein the spray nozzles (12) are moved during the water dispensing.
A laundry dryer (1) according to any one of the preceding claims, wherein the filter cleaning system (11) comprises a fluff transport system (33) with:
- a fluff collection container (34) arranged below the scraping member (15) and adapted to collect the water sprayed by the spray nozzles (12) and the fluff separated from the filter wall (9),

- a transport duct (35) that connects the fluff collection container (34) to a collection tray (37) which can be extracted and emptied by the user.
A fluff trap (8) for a laundry dryer (1), wherein the fluff trap (8) comprises a filter support structure (10), a sieve-filter wall (9) supported by the filter support structure (10) and a filter cleaning system (11),
wherein the filter cleaning system (11) comprises:
- one or more spray nozzles (12) supported by the filter support structure (10) and configured to spray one or more pressurized water jets (13) on the filter wall (9) to soak and detach fluff (14) from the filter wall (9), and

- a scraping member (15) supported by the filter support structure (10) in a scraping position against the filter wall (9),

- a filter movement device (16) configured to move the filter wall (9) with respect to the filter support structure (10) and with respect to the scraping member (15) so that the scraping member (15) brushes the soaked fluff (14) away from the filter wall (9).