DE102011017682B4 - Cooker hood with filter element - Google Patents

Abstract

Extractor hood (1), which has a fan (13) for sucking air into the extractor hood (1) and at least one filter element (2) for filtering out odorous substances from the air, which includes an odor filter (3), characterized in that The filter element (2) is a hollow body, the filter element (2) has a cover (24) which consists of air-impermeable material and closes the filter element (2) at the top, and the odor filter (3) covers at least part of the side surface (21) of the Filter element (2) forms, the odor filter (3) has a waveform and in the main flow direction (S) of the air is downstream of the fan (13).

Description

The invention relates to an extractor hood with at least one filter element according to the preamble of claim 1.

In DE 3529640 A1 discloses an extractor hood which has an odor filter which is designed as a filter magazine consisting of a number of independent partial filters. The filter magazine can be rod-shaped or ring-shaped. In one exemplary embodiment, a ring-shaped filter magazine is inserted into a pot which has a wall interruption on its circumference, which corresponds to the outlet opening of a partial filter. In this embodiment, a cover is provided with setting markings, which enable the partial filter currently in operation to be checked. Filter magazine and pot represent two separate components.

Known filter elements in extractor hoods for filtering out or separating odorous substances usually have a structure in which a filter element loaded with activated carbon is covered with a fleece. Here, the activated carbon filter element is usually placed in a plastic frame to which the fleece material is welded on the top and bottom. Such an activated charcoal filter is installed in the direction of flow in front of the extractor hood fan. In the DE 10 2009 023 241 A1 describes, for example, an extractor hood having a housing with an upwardly extending chimney. A suction fan device is arranged in the chimney. The housing has a filter device with an annular filter element on the underside. In a preferred embodiment, the filter element is arranged in a filter cassette which has air inflow openings in the edge or peripheral area.

A disadvantage of this known odor filter of extractor hoods is that the size of the effective filter surface through which the air to be cleaned can enter the filter element is small. In order to nevertheless achieve adequate cleaning of odorous substances from the air, it may therefore be necessary to provide several filter elements. However, due to the installation space available in an extractor hood, this cannot be implemented or can only be implemented to a limited extent. Alternatively, the height or thickness of the filter element can be selected to be large. However, this leads to increased air resistance, which in turn leads to increased noise development. In addition, the inflow of the extractor hood is negatively influenced by this structure and there is a loss of performance or performance of the extractor hood, in particular with regard to the extraction rate or vapor trapping rate.

The object of the present invention is therefore to create an extractor hood with a filter element, with which reliable cleaning of odorous substances from contaminated air, in particular vapors and fumes, is possible and in which the disadvantages of the prior art are eliminated or at least reduced .

The invention is based on the finding that this object can be achieved by minimizing the flow resistance that is generated by the filter element. In particular, the effective filter surface forms a three-dimensional contour for this purpose in order to maximize the surface area exposed to the flow.

The object is achieved by an extractor hood with the features of claim 1.

The filter element of the extractor hood includes an odor filter and represents a hollow body, and the odor filter forms at least part of the side surface of the filter element.

Unless otherwise stated, directional information such as top and bottom and corresponding designations such as top and bottom refer to the filter element in the installed state in the extractor hood.

The part of the filter element that contains the actual filter medium is called the odor filter. The odor filter consists of a filter material. The filter material in turn can consist of the filter medium or be loaded with it. Adsorbents, preferably activated carbon, are used as filter media, for example. However, other filter means can also be used.

According to the invention, the filter element, which is also referred to as a high-performance filter, is a hollow body. A hollow body is a three-dimensional body that has an inlet opening on at least one side to an interior space formed in the body. In the filter element according to the invention, the inlet opening, which is also referred to as the inflow opening, is preferably located on the underside of the filter element. The surface that connects the top of the filter element to the bottom of the filter element is referred to as the side surface of the filter element. In this case, the side surface represents an outer surface of the filter element. The side surface can consist of a single side wall. In this case, the filter element has, for example, a round cross section and the side wall bil det the lateral surface of the filter element. Alternatively, the side surface can also consist of several side walls. This can be the case, for example, with an angular cross section of the filter element. In the case of a rectangular cross section, the side surface is formed by four side walls, for example. These can represent separate pieces of filter material or be formed from a single piece of filter material by shaping, for example by bending or by pressing.

According to the invention, at least part of the side surface of the filter element is formed by the odor filter. In the case of a filter element with a plurality of side walls, for example, one or more of the side walls can be formed by the odor filter. If the side surface consists of a single side wall, part of the lateral surface of the filter element can be formed by the odor filter, for example. In addition to the side surface, a cover or a cover surface, which closes off the filter element at the top, can also be formed by an odor filter. The top surface can be made of the same filter material as the odor filter on the side surface. However, it is also possible to produce the top surface from a denser filter material.

Since the side surface of a hollow body is at least partially formed by the odor filter in the filter element according to the invention, the effective filter surface can be maximized with given horizontal dimensions. This is advantageous for the filter element according to the invention, which is used in a fume hood, since the horizontal dimensions, i.e. the width and depth of the filter element, are usually determined by the corresponding dimensions of a chimney or other housing in which the filter element is accommodated should, are limited. The effective filter surface, which is also referred to as the effective filter surface, is the surface of the odor filter through which the air to be cleaned can enter the odor filter. In the filter element according to the invention, the effective filter surface is therefore on the inside of the side surface of the filter element in the area in which it is formed by the odor filter. In contrast to filter elements in which the odor filter is designed as a horizontal plate or block, the size of the effective filter surface can be maximized in the filter element according to the invention by choosing a suitable height of the filter element.

By increasing the effective filter surface, the thickness of the filter material of the odor filter can be reduced. This reduces the pressure loss that occurs when the air to be cleaned flows through the odor filter. On the other hand, the increase in the effective filter surface and the reduction in thickness, which is possible with the filter element according to the invention due to the increase in the effective filter surface, minimizes the noise that occurs when the air flows against and through the odor filter.

According to the invention, the odor filter has a waveform. The waveform is also referred to below as a meander. A wave shape or meander is a shape of the odor filter or its filter material, in which the material thickness of the odor filter is constant over the surface of the odor filter and yet there are elevations and depressions in the surfaces of the odor filter. The opposite wave maxima of the waveform of the odor filter are preferably of the same magnitude. Preferably, the waves of the odor filter are in the form of harmonic or sinusoidal waves. Because the odor filter has a wave shape, the size of the effective filter surface can be further increased without having to increase the installation space required for the filter element in the height, width or depth direction. Thus, the advantages mentioned above, which result from the enlargement of the effective filter area, are further reinforced in this embodiment.

With a wave-shaped odor filter in the filter element according to the invention, the wave troughs and wave crests of the wave-shaped odor filter particularly preferably extend in the longitudinal direction of the odor filter. The longitudinal direction is the direction that extends from the lower end of the filter element to its upper end. The longitudinal direction of the odor filter can be perpendicular to the inlet or inflow opening. In the case of a horizontally installed filter element in an extractor hood, the longitudinal direction is therefore generally vertical. The maximum deviations from a center line of a wave-shaped odor filter are referred to as wave troughs and wave crests. The wave troughs and wave crests are also referred to below as wave maxima. The wave troughs and wave crests, which according to the preferred embodiment extend in the longitudinal direction of the odor filter, preferably run over the entire height of the odor filter. If the side face of the filter element is perpendicular to the inflow opening of the filter element, the wave troughs and wave crests can also run perpendicular to the inflow opening. However, it is also within the scope of the invention that the wave troughs and wave crests run from the bottom to the top of the odor filter, but are inclined to the surface normal of the inflow opening. at a filter element that has a plurality of side walls and, for example, has a rectangular cross section, the wave troughs and wave crests can run diagonally, for example, in the respective side wall. Furthermore, it is possible that the odor filter is not perpendicular to the inflow opening, but is at an angle of less than 90° to it. For example, the side surface of the filter element can form a cone shape or a truncated pyramid shape, with the cross section of the filter element decreasing towards the top.

An advantage of providing wave troughs and wave crests in the odor filter is that, in addition to increasing the effective filter area, the stability of the odor filter is also increased. This makes it possible to use odor filters with a lower material thickness. In addition, by aligning the wave troughs and the wave crests in the longitudinal direction of the odor filter, the hindrance during the oncoming flow can be reduced. In particular, with this alignment of the wave troughs and wave crests, the inflow obstacle is reduced compared to an alignment of the wave troughs and wave crests in the circumferential direction of the filter element.

It has been shown that different parameters have to be taken into account in order to set optimal operating conditions for the filter element, in particular to set a low pressure loss on the filter element.

Surprisingly, the inventors found that setting a suitable ratio between the wavelength and the material thickness of the odor filter can result in low pressure losses in the filter element element and thus eliminate the disadvantages of the prior art, such as high pressure losses.

The ratio of the wavelength to the material thickness of the odor filter is preferably in the range from 3 to 7. A range from 4.5 to 5.5 has proven to be particularly preferred. The ratio of the wavelength to the material thickness of the odor filter can preferably be 5. The wavelength is the distance between two adjacent wave troughs or wave crests. In the case of a uniform waveform, in which the troughs and crests are equidistant from a center line of the wave, the wavelength also represents the distance between two adjacent starting points of waves. The wave here comprises a trough and a crest, starting from the center line and ends at the midline. The wavelength can thus also be referred to as a period of the wave. The material thickness of the odor filter is preferably constant over its area. The material thickness can also be referred to as the thickness of the material of the odor filter.

Although it would have to be assumed that the smallest possible wavelength would be advantageous in order to increase the effective filter surface, the inventors recognized that the wavelength can only be minimized by taking the material thickness into account, without causing an undesirable increase in the pressure drop across the odor filter.

With a ratio of the wavelength to the material thickness in the range of 3 to 7 and preferably 5, the lowest possible outflow velocity with relatively high uniformity was achieved with a relatively low pressure loss, and the advantages of the filter element according to the invention were thus optimally used. In the preferred ranges of the ratio of wavelength to material thickness, material compression at the troughs and crests of the wave shape, which would lead to an increase in pressure, can be avoided in particular. The material thickness of the odor filter is mainly limited by the manufacturing process or the manufacturing options.

In addition or as an alternative to the ratio of the wavelength to the material thickness, the wave height is preferably also taken into account according to the invention when optimally designing the odor filter. The filter element preferably has a ratio of the wavelength to the wave height of the odor filter in the range from 0.5 to 3. This ratio is particularly preferably in the range from 0.5 to 1.5 and more preferably 1. In the preferred ranges it can be ensured that the wave height compared to the wavelength does not have such a high value that the outflow is hindered of the cleaned air would lead to. If the wave height is too high and the wavelength remains the same, the outflow is impeded by neighboring waves.

According to one embodiment, the filter element has a box shape and the odor filter at least partially forms at least three side walls of the box shape. The box shape of this embodiment is preferably open at the bottom. This embodiment is advantageous because the filter element is usually accommodated in a housing of the extractor hood, which has a rectangular cross section. Since the filter element in this embodiment also has a box shape, ie has a rectangular cross section, the available space can be optimally used and the effective filter area in this space can be maximized. Lies the housing in which the filter element is provided is, on a mounting wall, for example with so-called wall mounts, the back of the filter element is preferably designed to be airtight. This means that the other three side walls of the box mold are available for air to escape. In addition, a top surface of the filter element, which closes off the box shape at the top, can also serve as an effective filter surface.

According to the invention, the filter element has a cover made of air-impermeable material. The cover is a part of the filter element that closes it off at the top. The cover here has the same shape as the upper cross section of the filter element. The cover can be present as a separate component or can be designed in one piece with the side surface. By closing the filter element upwards, the air that has entered the filter element is reliably guided to the side surface of the filter element, which at least partially consists of the odor filter. If the top surface of the filter element is made of an air-permeable material and thus also serves as an odor filter, the air in the filter element also flows through this surface. In this embodiment, however, the air permeability of the top surface is preferably lower than that of the side surface. Thus, in this embodiment as well, an exit of the air via the side surface can be further ensured.

The odor filter can be made from a wide variety of materials. For example, the odor filter can be a foam body that is loaded with filter media. Alternatively, the odor filter can be designed as a mat or fleece, for example, and have filter means, preferably activated carbon. These types of odor filter are advantageous because a low material thickness can be realized with a foam body, a mat or a fleece, each of which is loaded with activated carbon. The odor filter can also consist entirely of the filter medium, for example activated carbon. The material thickness is only limited by the manufacturability of the filter material. In addition, the required amount of filter medium to achieve the desired cleaning results of the air must be made available even with low material thickness.

In addition to the odor filter, the filter element can have support means, for example frames, which on the one hand keep the shape of the odor filter and on the other hand enable or facilitate installation in an extractor hood by being used to mount it on a housing of the extractor hood.

According to the invention, the extractor hood has a fan for sucking air into the extractor hood and at least one filter element for filtering out odorous substances from the air, the filter element representing a filter element according to the invention and being located downstream of the fan in the main flow direction of the air.

The arrangement of the filter element after the fan has the advantage that the air to be cleaned of odorous substances can be pressed through the odor filter. Because the filter element in the extractor hood according to the invention is provided with an odor filter, which represents at least part of the side surface of the filter element, the filter element has small dimensions, especially in the width and depth directions, but there is still a large filter surface. These small dimensions of the filter element make it possible to install the filter element in a position downstream of the fan. The air is routed from the fan to the filter element, for example via a pipe socket that is connected to the fan. The air that has passed through the filter element and is thus cleaned then exits via openings in a chimney or duct of the extractor hood that surrounds the fan and the filter element. Depending on the shape of the extractor hood, these outlet openings can be provided, for example, on three or four of the side surfaces of the duct. In the extractor hood according to the invention, the filter element can also be provided in a separate housing placed on the chimney instead of in the chimney of the extractor hood itself. The odor filter particularly preferably has a wave shape. The extractor hood is preferably a recirculation hood.

Advantages and features that are described with regard to the filter element used according to the invention apply--insofar as applicable--correspondingly to the extractor hood according to the invention and vice versa.

• 1: eine schematische Blockansicht einer Ausführungsform der erfindungsgemäßen Dunstabzugshaube;
• 2: eine perspektivische Unteransicht einer Ausführungsform des erfindungsgemäßen Filterelementes;
• 3: eine schematische Explosionsansicht der Ausführungsform des Filterelementes nach 2;
• 4: eine perspektivische Draufsicht auf eine Ausführungsform des erfindungsgemäßen Filterelementes mit Montagehilfe;
• 5: eine schematische Seitenansicht des Filterelementes nach 4;
• 6: eine schematische Schnittansicht des Filterelementes nach 5 entlang der Schnittlinie A-A;
• 7: eine schematische Schnittansicht des Filterelementes nach 5 entlang der Schnittlinie B-B; und
• 8: eine schematische, perspektivische Schnittansicht einer Ausführungsform des erfindungsgemäßen Filterelementes.

The invention is described in more detail below again with reference to the accompanying drawings. Show it:

• 1 : a schematic block view of an embodiment of the extractor hood according to the invention;
• 2 : a perspective bottom view of an embodiment of the filter element according to the invention;
• 3 : a schematic exploded view of the embodiment of the filter element according to FIG 2 ;
• 4 : a perspective plan view of an embodiment of the filter element according to the invention with an assembly aid;
• 5 : a schematic side view of the filter element 4 ;
• 6 : a schematic sectional view of the filter element 5 along section line AA;
• 7 : a schematic sectional view of the filter element 5 along section line BB; and
• 8th : a schematic, perspective sectional view of an embodiment of the filter element according to the invention.

In 1 an embodiment of an extractor hood 1 according to the invention is shown. The extractor hood 1 consists of a viewing screen 10 and a chimney 11 extending above the viewing screen 10, which can also be referred to as a channel. A grease filter 12 is provided in the viewing screen 10 . In the chimney 11, the fan 13, which is also referred to as the fan of the extractor hood, is arranged. In the illustrated embodiment, a pipe socket 14 is provided on the fan 13 and extends upwards from the fan 13 . A filter element 2 designed according to the invention is arranged above the pipe socket 14 in the upper region of the chimney 11 . The filter element 2 is accommodated in the chimney 11 in such a way that the inflow side 20 is directed downwards in the direction of the fan 13 .

Air from the room in which the extractor hood 1 is mounted is sucked into the extractor hood 1 via the fan 13 . Here, the air at the grease filter 12 is freed from droplet-shaped and solid impurities. The pre-cleaned air then reaches the fan 13 via which it is transported in the direction of the filter element 2 via the pipe socket 14 - if one is provided. The air which has been pre-cleaned but is still laden with odorous substances enters the filter element 2 via an inflow opening 20 which is located on the underside of the filter element 2 . Here, the air gets into the interior of the filter element 2 and leaves the filter element 2 via the side surface 21 of the filter element 2. This is in 1 indicated by the dashed arrows. After exiting the filter element 2 via the side surface 21, the air can be returned to the room in which the extractor hood 1 is operated via openings (not shown) on the chimney 11.

In 2 an embodiment of the filter element 2 according to the invention is shown in a perspective view. In the illustrated embodiment, the filter element 2 has an odor filter 3 which forms the entire lateral surface 21 of the filter element 2 . Furthermore, the filter element 2 comprises a lower frame 22 and an upper frame 23. The two frames 22, 23 are provided on the outside of the odor filter 3 at its upper end and its lower end. At the top is the filter element 2, as in 3 better seen, closed by a cover 24.

As can be seen from the 2 until 7 results, the odor filter 3 in the illustrated embodiment has a box shape. In this case, a hollow body is referred to as a box shape, which has an essentially rectangular cross section, the side surface of the hollow body having a corrugated shape. In the illustrated embodiment, the four side walls 21 ′ of the filter element 2 are each formed entirely by the filter material of the odor filter 3 . The area between the lower end of the upper frame 23 and the upper end of the lower frame 22 defines the height H of the effective filter area.

The odor filter 3 has a waveform. The wave troughs 31 and wave crests 32 forming the waves 30 extend over the entire height of the odor filter 3 and in particular over the height H of the effective filter surface. The wave maxima directed into the interior of the filter element 2 are referred to as wave troughs 31 . The frames 22, 23 have a shape on the inside that corresponds to the corrugated shape of the odor filter 3. As a result, the odor filter 3 is held in shape by the frames 22, 23 and is optionally also attached to the extractor hood via the frame or held in position there. For assembly purposes, as in 4 until 7 shown, an additional mounting core 4, which can consist of polystyrene, for example, can be used. The outside of the mounting core 4 corresponds to the inside shape of the odor filter 3, that is, the outside of the mounting core 4 has a wave shape. The mounting core 4 projects beyond the upper edge of the deodorizing filter 3 and the upper frame 23 . Before use in the extractor hood 1, however, the mounting core 4 is removed and the cover 24 is applied.

As in 6 more specifically, in the illustrated embodiment, the ratio of the depth T of the box-shaped body formed by the odor filter 3 to the wave height WH is 7.5. The ratio of the wavelength WL to the wave height WH is 2 in the illustrated embodiment. However, the ratio is preferably 1. The ratio of the wavelength WL to the material thickness D in the illustrated embodiment is approximately 5, in particular 4.8.

In the embodiment shown, the filter element 2 has four crests 32 and three troughs 31 on each of the side walls 21 . However, the invention is not limited to the number of wave crests 32 and wave troughs 31 shown. Rather, the number of shafts 30 is selected in particular as a function of other parameters of the odor filter 3, such as the material thickness and the available space.

In 8th a schematic representation of the flow conditions in the filter element 2 is shown. The filter element 2 is only shown schematically here, in particular no frames are shown. The air from which odorous substances are to be removed enters the interior of the filter element 2 via the inflow opening 20 . Since the filter element 2 is closed at the top by an airtight cover 24 , the air is guided to the side surface 21 of the filter element 2 . The side surface 21 consists of the odor filter 3. The air is therefore cleaned via the filter material of the odor filter 3 and leaves the filter element 2.

It has been shown that the best results can be achieved with a wavelength to material thickness ratio of 5 for all parameters considered, such as outflow velocity and pressure loss. At this optimum operating point, the wavelength and the wave height can each be 50 mm, for example.

With the present invention, the fact that the pressure loss in the corrugated cross section of the odor filter increases with increasing wave height, the outflow speed increases, but becomes more uniform, can be taken into account. In addition, the fact can be taken into account that as the wave height decreases, the pressure loss in the corrugated cross-section of the odor filter decreases, the outflow speed decreases, but becomes more uneven and the maximum filter surface is reduced. For this purpose, the wavelength to wave height ratio can be selected appropriately.

With the filter element according to the invention, suitable values can be achieved for the outflow velocity and the uniformity of the outflow velocity. As a result, the development of noise in the filter element according to the invention, in particular in a filter element with a corrugated odor filter with a wavelength to material thickness ratio of 3 to 7, can be minimized. The pressure loss at the odor filter is also kept low.

The filter element according to the invention has the best performance in a direct comparison to other standard filter elements that have been optimized in terms of geometry and production technology. In particular, the delivery volume of an extractor hood in which the filter element is used can be increased. The vapor trapping rate of the extractor hood is also increased and the noise level is minimised. This is primarily due to the low pressure losses due to the adjustment of the period length of the meander, i.e. the wavelength of the waves of the odor filter. This also makes it possible to bring more activated carbon into the volume flow and thus increase the service life / filter change time. The larger, unimpeded inflow surface ensures uniform utilization of the filter surface and lower flow losses. The flow simulation has confirmed the more uniform outflow with low pressure losses compared to alternative meander filters.

According to a preferred embodiment of the filter element, the odor filter material, in particular an activated carbon filter material, meanders in a defined ratio of the periodic length of the meander to the material thickness of the odor filter. This ensures that there is the largest possible surface area and minimal obstruction to the outflow.

• - Geringer Druckverlust im Filterelement und dadurch größtmögliches Fördervolumen der Dunstabzugshaube
• - Reduzierung der Geräuschkennwerte durch Dämpfung der Geräuschabstrahlung im Filterelement mittels Reflexion
• - Reduzierung der Geräuschkennwerte durch größtmögliche An- und Abströmfläche ohne Veränderung des Querschnitts
• - Lange Filterstandzeit (<1Jahr) durch größtmögliche Aktivkohlemenge bei geringer Aktivkohlefilter-Dicke (Vermeidung hoher Druckverluste)
• - Mindestens eine 3-seitige Abströmung

With the filter element according to the invention it is possible to meet the following requirements:

• - Low pressure loss in the filter element and thus the greatest possible delivery volume of the extractor hood
• - Reduction of the noise characteristics by attenuating the noise radiation in the filter element by means of reflection
• - Reduction of the noise characteristics through the largest possible inflow and outflow area without changing the cross section
• - Long filter service life (<1 year) due to the greatest possible amount of activated carbon with a low activated carbon filter thickness (avoidance of high pressure losses)
• - At least a 3-sided outflow

The present invention has a number of advantages. In particular, a possibility is created to create the largest possible filter surface in a horizontally limited installation space. On the one hand, this increases the reduction in odors and, on the other hand, the air flow in the extractor hood is only slightly affected, which minimizes the pressure drop across the filter element and thus also the noise development. Finally, the filter element according to the invention is easy to produce and in a fume hood hood, especially above the fan, mountable.

Reference List

1

extractor hood

10

screen

11

Chimney

12

grease filter

13

Fan

14

pipe socket

2

filter element

20

inflow opening

21

side face

21'

Side wall

22

lower frame

23

upper frame

24

lid

3

odor filter

30

Wave

31

trough

32

wave crest

4

assembly core

WL

wavelength

WH

wave height

D

Material thickness odor filter

T

Deep odor filter body

B

Wide odor filter bodies

H

Height of the effective filter area

S

main flow direction

Claims (6)

Extractor hood (1), which has a fan (13) for sucking air into the extractor hood (1) and at least one filter element (2) for filtering out odorous substances from the air, which includes an odor filter (3), characterized in that The filter element (2) is a hollow body, the filter element (2) has a cover (24) which consists of air-impermeable material and closes the filter element (2) at the top, and the odor filter (3) covers at least part of the side surface (21) of the Filter element (2) forms, the odor filter (3) has a waveform and in the main flow direction (S) of the air is downstream of the fan (13). Extractor hood (1) after claim 1 , characterized in that wave troughs (31) and wave crests (32) of the wave-shaped odor filter (3) extend in the longitudinal direction of the odor filter (3). Extractor hood (1) according to one of Claims 1 or 2 , characterized in that the ratio of a wavelength (WL) to a material thickness (D) of the odor filter (3) is in the range from 3 to 7 and is preferably 5. Extractor hood (1) after claim 3 , characterized in that the ratio of the wavelength (WL) to a wave height (WH) is in the range 0.5 to 3 and is preferably 1. Extractor hood (1) according to one of Claims 1 until 4 , characterized in that the filter element (2) has a box shape and the odor filter (3) at least partially forms at least three side walls (21 ') of the box shape. Extractor hood (1) according to one of Claims 1 until 5 , characterized in that the odor filter (3) is designed as a mat or fleece and preferably has activated carbon.

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