EP2333148B1 - Method for cleaning process air in a laundry dryer and laundry dryer - Google Patents

Description

The invention relates to a method for cleaning a process air flow of a laundry drying apparatus during a drying operation by means of at least one lint filter, wherein the process air stream is passed through a plurality of lint filters, wherein at least one lint filter for retaining hair and at least one other lint filter for retaining short-fiber lint is set up and a clothes drying device, which is set up to carry out the method.

Such a method and such a laundry drying device will be apparent from the document DE 10 2007 012 071 A1 , There, a laundry drying device with a plurality of lint filters is described, which lint filter can be flowed through successively by a process air flow and lint different size catching filter materials. These lint filters may in particular be combined in a filter cassette.

A lint filter for a clothes dryer, e.g. a washer-dryer or a tumble dryer, is typically used in a process air duct of the laundry dryer to retain from a load laundry or textiles in a drying process entrained finely divided particles and fibers, referred to collectively as fluff, so that they are not also located in the process air duct functional units such as blower , Contaminate or even clog pumps, heaters, heat exchangers, waterways, airways, etc. For this purpose, lint filters have hitherto been a flat lint filter made of material, in particular plastic gauze, a small-pored foil or a lattice. In order to remove the lint adhering to the lint filter, the lint filter is usually removable and can be cleaned after removal by a user.

A lint filter of this type is from the Scriptures WO 2007/057264 A1 known, where there is additionally an odor filter, eg with activated carbon, is present.

From the Scriptures WO 2008/110451 A1 shows an arrangement comprising a first lint filter and a second lint filter, wherein the first lint filter and the second lint filter are arranged one behind the other and to flow through successively process air. The second lint filter forms a permeable for the process air wall of a filter cartridge.

A disadvantage of the conventional lint filters is that still a certain amount of lint and the like foreign bodies such as long fibers and especially hair can pass through the lint filter. This is because the filter material for retaining lint must be designed so that a free passage area of about 35% to 45% and a mesh size of 100 to 200 microns are guaranteed because otherwise the lint filter is added too quickly and the air resistance becomes too high. A significantly finer filter material would cause the drying process would extend significantly, since the heater due to the high air resistance and the associated low volume flow heats up strongly towards the end and therefore must be operated with a significantly reduced heating power. Finer filter material with a mesh size of significantly less than 150 microns also tends to clog quickly during the drying process by particles from detergent or lime residues in the laundry. This means, however, that the hair in the process air, which have a diameter between 10 .mu.m and 60 .mu.m, especially in domestic animals and 35 microns to 120 microns in humans, through the conventional filter material and into the downstream air ducts and components (eg heating, Heat exchanger, blower, etc.) can enter and enter the water supply and cause problems in the usually very simple condensate pumps (eg blockages through hair bundles). Also, hair can wrap around a drive shaft of a blower and block this blower. In addition, hair in the water tend to stick together and form clumps so that they can also attach to this short-fiber lint, thereby forming clumps of hair and lint, which lead to blockages in pumps and pipelines located behind. Thus, while short-fuzz lint usually pass easily through the pump, especially long-fiber foreign bodies and especially hair is an extreme problem.

It is the object of the present invention to avoid the abovementioned disadvantages and, in particular, to provide a possibility for the effective retention of hair in a process air duct of a laundry drying apparatus.

This object is achieved by a method and a laundry drying apparatus according to the features of the respective independent claim. Preferred embodiments are the respective dependent claims and the following description and the accompanying drawings removable; preferred embodiments of the method correspond to preferred embodiments of the laundry dryer and vice versa, and this even if it is not explicitly indicated herein.

The object is achieved according to the invention by a method for cleaning a process air flow of a laundry dryer during a drying process by means of at least one lint filter, wherein the process air flow is passed through a plurality of lint screens, wherein at least one lint filter for retaining hair and at least one other lint filter for retaining short-fiber Furthermore, the lint filter for retaining the hair has a mesh size of more than 20 microns and less than 60 microns, the at least one other lint filter for retaining short-fiber lint has a mesh size of 100 .mu.m to 200 .mu.m and a free passage area of 36% to 45%, and the process air flow during the drying process first flows through the at least one lint filter to retain the hair and then the at least one other lint filter for retaining the short-fiber lint.

As a result, hair can be removed separately from lint from the process air stream. The lint-retaining lint may retain the lint without an increased risk of clogging, while the lint-retaining lint can effectively remove it from the process air stream. Here and below can be understood by hair and other pet hair, human hair and / or long-fiber fluff.

According to the invention, the lint filters have different mesh sizes, wherein the at least one lint filter for retaining hair has a mesh width of less than 60 μm. Through this mesh size, a large part of the hair can be filtered out. In addition, according to the invention, the at least one lint filter for retaining the hair has a mesh width of more than 20 μm. This prevents clogging of this lint filter from filtering out the hair in practice.

According to the invention, during a drying process, at least the at least one lint filter for retaining the hair flows through the process air and then the at least one other lint filter for retaining the lint. This embodiment makes the property of hair own, that although they are hygroscopic (and therefore adhere well to damp, to be dried laundry), but the water is bound to the surface of the hair only relatively weak. It results itself that on the laundry to be dried adhesive hair are dried on their surfaces after a short period in the drying process and can be easily replaced by the volume flow of process air from the laundry. Consequently, the hair gets to the lint filter before other lint from the textiles get there. Thus, when the process air stream is first passed over the at least one lint filter to hold the hair, almost all of the hairs can be retained there without this lint filter being clogged with lint. As a result, the mesh size can be kept comparatively small, which further increases a retention effectiveness for the hair. The lint filter used thereafter for retaining the lint filters a process air substantially free of hair.

It is a preferred embodiment that the lint screens have gauze as the filter material.

It is also a preferred embodiment that at least one air guide, in particular air guide plate, is adjusted for the alternating passage of the process air flow through the plurality of lint filters.

It is a particular preferred embodiment that the at least one lint filter for retaining the hair is flowed through by the process air for 5 to 15 minutes, in particular about 10 minutes. It has been found that essentially all hair reaches the lint filter during this time, as long as they are not held in place by mechanical forces (jamming in gaps, etc.). As a result, a precise temporal separation between the separation of the hair and the deposition of the lint and other residues (detergent residues, etc.) is possible.

The at least one lint filter is traversed to retain the hair, for example, from the beginning of the drying process of the process air.

The object is also achieved by a laundry drying apparatus which is adapted to perform such a method, and which comprises: a central control unit, a process air duct with at least two parallel branches, each of the branches has a respective lint filter, and a through the central control unit controllable air guiding means for deflecting a in the Process air duct guided process air between the branches. The controllable air guiding means is controllable by means of a central control unit of the laundry drying apparatus. The time-controlled guidance system makes the filtering of hair even more effective. Hair tends to thread into the mesh of the gauze and work its way through the gauze slowly through process air support. By the timed control system, this behavior is advantageously interrupted, so that even threaded hair stuck in the gauze and can be easily removed by the user after drying.

It is a preferred and advantageous development for simple handling and cleaning, that the lint filters are combined in a common, removable unit.

Fig.1

ein mögliches Ablaufdiagramm zur Implementierung des Verfahrens; und

Fig.2

eine skizzierte Schnittdarstellung einer Seitenansicht eines Wäschetrocknungsgeräts, das dazu eingerichtet ist, das Verfahren aus Fig.1 durchzuführen.

In the figures of the accompanying drawing a preferred embodiment of the invention is shown schematically and will be described below. In the drawing, the same or equivalent elements are provided with the same reference numerals for clarity. In the drawing show:

Fig.1

a possible flowchart for implementing the method; and

Fig.2

a sketched sectional view of a side view of a laundry drying apparatus, which is adapted to the process from Fig.1 perform.

Referring to both figures, in a first step S1, a drying process of the clothes dryer 1 is started. In this case, a process air blower 2 is activated in the tumble dryer 1, which circulates process air P in a process air duct K. The process air channel K comprises in succession, but not necessarily in this order, a - e.g. rotatable - drying drum 3 for holding laundry to be dried, a heater for heating the process air (not shown) and a condensation unit for condensing out of the wash water (not shown), both of which are also activated. A tumble dryer with these components is known.

In contrast to known tumble dryers, the process air duct K of the tumble dryer 1 shown here is provided with two parallel branches Ka and Kb, each of the branches Ka, Kb having a respective lint filter 4, 5. In detail, a first lint filter 4, which is set up for retaining hair, is introduced into a first branch Ka. In a second branch Kb a second lint filter 5 is introduced, which is adapted to retain lint. The first lint filter 4 is extensively equipped with a plastic gauze, which has a mesh size of more than 20 microns and less than 60 microns. This hair can be retained particularly effective. The second lint filter 5 is flat with a conventionally used one Plastic gauze equipped, which has a passage area of about 36 - 45% and a mesh size of 100 microns to 200 microns.

The tumble dryer 1 further comprises an air guide in the form of a movable air baffle 6, by means of which the process air flow can be selectively directed either by the first branch Ka or by the second branch Kb.

After or with the start of the drying process in step S1, the air guide plate 6 is set so that the process air P flows through the first branch Ka and thus through the first lint filter 4. The second branch Kb is blocked. At the beginning of the drying process, the surface of the laundry or textiles is first dried, so that typically adhering hair can dissolve there and be entrained with the process air P. Fluffs, on the other hand, still stick in practice. The offset with the hair air flows through the first lint filter 4, where the hair is held back. Since virtually no lint is present in the process air P, the first lint filter 4 does not clog up, and a sufficiently high volume flow can be maintained.

After about 10 minutes (depending on, for example, the type of laundry and heating stage), most of the hair is removed from the laundry and deposited on the first lint 4. Now the lint starts to get out of the laundry. Therefore, in a step S3, the air baffle 6 is switched or changed so that the process air P now flows through the second branch Kb and thus through the second lint filter 5. The first branch Ka, however, is blocked. Now the lint-laden process air P is guided in a conventional manner by the second lint filter 5 and filtered there, but the process air is hair-free.

In a following step S4, the drying process can be ended.

Thereafter, in a step S5, the lint filters 4 and 5 are removed for cleaning. Since the lint screens 4, 5 are combined in a common, removable unit, for example, have a common frame, the removal and cleaning are user friendly.

Of course, the present invention is not limited to the embodiment shown.

Thus, the lint filter or the lint filters can also be accommodated in a door of the drying device. Also, the lint filter or the lint filters can be arranged above or next to the drying drum.

LIST OF REFERENCE NUMBERS

1

clothes dryer

2

Process air fan

3

dryer drum

4

first lint filter

5

second lint filter

6

Air baffle

P

process air

K

Process air duct

ka

first branch

kb

second branch

Claims (6)

1. Method of cleaning a process air flow (P) of a laundry drier (1), during a drying process, by means of at least one lint filter (4, 5), in which the process air flow (P) is conducted through a plurality of lint filters (4, 5), wherein at least one lint filter (4) is arranged for retaining hairs and at least one other lint filter (5) is arranged for retaining short-fibred lint, characterised in that:

   - the lint filter (4) for retaining hairs has a mesh size of more than 20 µm and less than 60 µm;

   - the at least one other lint filter (5) for retaining short-fibred lint has a mesh size of 100 µm to 200 µm as well as a free passage area of 36% to 45%; and

   - the process air flow (P) during the drying process initially flows through the at least one lint filter (4) for retaining hairs and thereafter the at least one other lint filter (5) for retaining short-fibred lint.
2. Method according to any one of the preceding claims, in which the lint filter (4, 5) comprises gauze as filter material.
3. Method according to one of the preceding claims, in which at least one air guide means (6), particularly air guide plate (6), is adjusted for alternate conduction of the process air flow (P) through the plurality of lint filters (4, 5).
4. Method according to any one of the preceding claims, in which the at least one lint filter (4) for retaining hairs is flowed through by the process air flow (P) for 5 to 15 minutes, particularly approximately 10 minutes.
5. Laundry drier (1) which is equipped for performing a method according to any one of the preceding claims and which comprises:

   - a central control unit;

   - a process air channel (KI) with at least two parallel branches (Ka, Kb), wherein each of the branches (Ka, Kb) has a respective lint filter (4, 5), and

   - an air guide means (6), which is controllable by the central control unit, for deflecting a process air (P), which is guided in the process air channel (K), between the branches (Ka, Kb).
6. Laundry drier according to claim 5, in which the lint filters (4, 5) are combined in a common removable unit.

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