DE102010005114A1 - Filtering element, preferably interior filter, useful for motor vehicles, comprises first layer with activated carbon particles, filtering material layer, second layer with activated carbon particles and catalytic material to degrade ozone - Google Patents

Abstract

Filtering element (1), preferably interior filter comprises: a first layer (3) with activated carbon particles to adsorb contaminants and to provide purified interior air; a filtering material layer (2); a second layer (4) with the activated carbon particles; and/or a catalytic material for degrading ozone. An independent claim is also included for a filter system comprising the filtering element, a filtering element holder to hold the filtering element and an ozone generating device (6), where the second layer of the filtering element is arranged towards the ozone generating device.

Description

Technical area

The present invention relates to a filter element, in particular an interior air filter for motor vehicles. Furthermore, a method for producing filter elements will be described.

To z. For example, in the automotive field, to filter fluids such as fuels, other equipment, or indoor air, pleated or non-woven filter fabrics are often used. In order to achieve a reduction of odors and harmful gases, activated carbon particles are often applied in layers or on the filter fleece materials. The activated carbon then acts as an adsorbent. The filtered and cleaned air is also usually brought in an air conditioning or heating to the desired temperature for the vehicle interior.

In particular, when using motor vehicle air conditioning systems, it is necessary to disinfect the evaporator used at regular intervals, as condensed water forms, which allows the growth of germs, fungi, bacteria or algae. In the past, in particular ozone was used as a disinfectant, which usually kills the germs. However, the reactive ozone can attack the filter materials even on contact with the filter elements. In particular, it is possible for ozone to decompose or degrade activated carbon particles stored in the filter element.

On the one hand, sufficiently high ozone concentrations are necessary for reliable disinfection of the air conditioning or air distribution system. On the other hand, the high ozone concentrations also attack the cabin air filters, in particular their potentially present activated carbon constituents. Thereby, the adsorption effect and thus efficiency with respect to the purification and treatment of the air through the filter can be reduced. In this respect, the ozone disinfection leads to a shorter service life of filter elements.

State of the art

To counteract the degradation of Aktivkohleadsorbens, for example, in the DE 102 19 966 A1 proposed to impregnate the activated carbon particles used. For example, activated carbon particles have been impregnated with an organic acid and bromide or iodide salts to increase the resistance to ozone.

In the DE 10 2004 030 998 A1 It has been proposed to provide air dampers in the air distribution system which close when ozone released for disinfection is present.

In addition, from the DE 100 05 197 A1 known to arrange ozone catalysts at the air inlet or air outlet openings of air supply ducts, heating or air conditioning systems of a motor vehicle.

The aforementioned known measures do not prevent the filter elements used in the air distribution system and equipped with activated charcoal particles from being exposed to ozone, and this partly adversely affects the adsorption capacity of the filter elements.

Against this background, the object of the present invention is to provide an improved filter element.

Disclosure of the invention

This object is achieved by a filter element according to claim 1.

Accordingly, a filter element is proposed, which is in particular a cabin filter for a motor vehicle, which comprises a first layer with activated carbon particles for adsorbing contaminants and for providing purified indoor air. The filter element further comprises a filter material layer and a second layer with activated carbon particles and / or a catalyst material for the decomposition of ozone.

Due to the presence of the second layer, which can also be referred to as the ozone sacrifice layer, it is largely prevented that the filter element used is impaired in its functionality during ozone purge operations. Namely, the second layer is preferably installed with activated carbon particles or with the catalyst material in the direction of the ozone-containing air. This means that at most the sacrificial layer is attacked by the reactive ozone and thereby protects the ozone-removed first layer and the filter material layer.

It is possible to provide the first layer and / or the second layer with a carrier material, such as filter fleece, to carry the activated carbon particles or the catalyst material. It is also possible to design the filter material layer as a carrier material for the activated carbon particles for adsorbing contaminants and at the same time as a carrier material layer for activated carbon particles for the degradation of ozone or the catalyst material for the degradation of ozone. A layer can also be understood to mean a flat region of particles on a carrier material.

The filter material layer and the first layer with activated carbon particles preferably form an adsorption layer for the retention of odor and contaminants. In this case, specifications are preferably fulfilled with regard to the retention of test gases, such as n-butane, toluene, sulfur dioxide or nitrogen oxides.

In one embodiment of the filter element, the first layer comprises in particular activated carbon particles which are produced from coconut shells. There are z. B. CCl ₄ activities of 50-70% in coconut shells as starting material for activated carbon. The resulting pore distribution is then matched to the retention of the aforementioned test gases, for example. The activated carbon particles of the first layer preferably have a higher degree of activation than the activated carbon particles of the second layer.

The second layer, especially when it is equipped with activated carbon particles, is at least partially degraded in contact with ozone. This sacrificial layer, or the second layer with activated carbon particles does not serve the fulfillment of requirements specification regarding the retention of test gases, but only the degradation of ozone. The sacrifice day protects the actual activated carbon layer for adsorbing contaminants or gases. The material of the sacrificial layer or second layer with activated carbon particles can be activated carbon particles based on other organic materials such. B. peat, wood or hard coal have. In particular, a specific surface area and / or a pore distribution of the (inferior) activated carbon particles of the second layer are preferably adapted for ozone depletion. In the sacrificial layer, in particular, it is not necessary to meet the usual requirements for interior activated carbons. Therefore, inexpensive activated carbon materials can be used, since a filter and odor adsorption effect is not necessary in principle.

Alternatively, the second layer comprises a catalyst material with manganese dioxide, iron oxide hydrate or similar metals. Particularly suitable as catalysts are MnO ₂ , moss, CuO, Fe ₂ O ₃ , Ag ₂ O, NiO, CO ₃ O ₄ , WO ₃ , V ₂ O ₅ , SnO ₂ , Pt or Pd. Also redox-active surfaces such as gold, silver or platinum are conceivable. Transition metals such as manganese, iron, vanadium, platinum metals or lead dioxide as well as mixed oxides based on titanium / aluminum or iron / barium are suitable for the second layer as the catalyst material. The second layer protects the first Adsorberlage when flushing with ozone.

In one embodiment of the filter element, the first layer, the filter material layer and the second layer are connected to one another. For example, the layers can be attached to each other, for example by means of adhesive strips, and processed into a pleated bellows.

In a further embodiment of the filter element, the second layer is designed such that the second layer can be exchanged without destroying the first layer or the filter material layer. In this case, the second sacrificial layer can be applied to the first filter material layer, for example with fastening means or punctually provided adhesive sites. It is also conceivable that the first layer and the filter material layer are folded and pleated because of the desired high surface area, while the second sacrificial layer layer is merely glued onto the resulting fold edges.

The second layer may also be formed as a removable from the first layer of the filter material layer grid. This results in a particularly simple replacement, so that different exchange intervals for the actual filtering adsorption on the one hand and the sacrificial layer on the other hand can be realized.

It is further proposed a filter assembly with a filter element as described above, which comprises a filter element receptacle for holding the filter element and an ozone generating device. In this case, the second layer of the filter element is arranged ozone generating device side.

The filter arrangement can be used, for example, in an air distribution system of a motor vehicle, wherein the ozone generating device serves to form ozone and thus to disinfect further devices present in the air distribution system. It is Z. B. possible that a heat exchanger of an air conditioner is present in the vicinity of the ozone generating device and its fins or structures are disinfected by the ozone. In this respect, the second layer or sacrificial layer or sacrificial layer is provided on the clean air side of the filter element. In this respect, untreated air, from the outside, flows through the pipe system of the filter arrangement, the filter element first through the first layer and the filter material.

The filter arrangement is preferably set up such that ozone generated by the ozone generating device can be transported exclusively by diffusion to the second layer. In this respect, it is preferably ensured that in the case of ozone purge processes, for example for air conditioning disinfection, no active flow takes place with the aid of a fan of the interior filter, but the higher ozone concentration is present only on the side of the sacrificial layer. Any mass transfer then takes place mainly by diffusion.

The ozone generating means is preferably arranged to cause ozone purge at regular intervals.

In a further development, the filter arrangement further comprises an evaporator device, and the ozone generating device is provided between the heat exchanger and the second layer of the filter element.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments of the filter element or the filter arrangement described above or below with regard to the exemplary embodiments. The skilled person will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further embodiments of the invention are the subject of the dependent claims and the embodiments of the invention described below. Furthermore, the invention will be explained in more detail by means of embodiments with reference to the accompanying figures.

Brief description of the drawings

It shows:

1 a cross-sectional view of a filter assembly with a first embodiment of a filter element;

2 : Cross-sectional views of a second embodiment of a filter element; and

3 : Cross-sectional views of details of several layers of further embodiments of a filter element.

In the figures, identical or functionally identical elements, unless otherwise indicated, have been given the same reference numerals.

Embodiment (s) of the invention

1 shows a cross-sectional view of a filter assembly, as z. B. can be used for indoor air purification and conditioning for a motor vehicle. The filter assembly is used for cleaning and conditioning of external raw air RO, which is passed as clean air RE, for example, in a passenger compartment. In this respect, a housing 17 provided with an inlet opening 8th and an exit opening 9 ,

The air conditioning of the raw air is basically done by an air conditioning module 7 , which usually includes an evaporator, condenser, compressor and an expansion device. The evaporator which cools the air often produces condensation water which, together with contaminants that have been introduced, is suitable as a breeding ground for germs and must be sterilized. In order to regularly perform a disinfection, therefore, an ozone generating device is provided, which supplies reactive disinfecting ozone O ₃ .

Furthermore, a filter holder with fasteners 5 provided, in which a filter element 1 is introduced. The filter element 1 It cleans the incoming raw air RO and removes dust particles, odors and noxious gases.

This includes the filter element 1 a first location 3 , which is equipped with odor and gas adsorbing activated carbon particles. The filter element 1 includes a second layer on the ozonizer side 4 , which is equipped with other activated carbon particles or includes a catalyst material for the degradation of ozone. The in the second position 4 potentially present activated carbon particles are used for the degradation of ozone O ₃ , which in the disinfecting or rinsing phase in concentrations, for example, up to 100 ppm between the filter element 1 and the climate module 7 is present. The filter element also has a filter material layer 2 between the first (cleaning) position 3 and the sacrificial situation 4 ,

At the in 1 The arrangement shown is largely prevented that for the purification and adsorption of present in the raw air odors or pollutants activated carbon particles are attacked by the ozone. Rather, sacrificial layer side takes place a degradation of the ozone O ₃ by the (rather inferior) activated carbon particles in the second layer 4 : C + ₂ O ₃ → CO ₂ + 2O ₂ . An attack on the pore structure, which binds odors and noxious gases in the cleaning layer 3 is present, is therefore largely prevented, so that no impairment of the adsorption occurs.

The cleaning situation 3 or position referred to as the first layer with activated carbon particles for reducing pollutants is also referred to below as the odor adsorption layer, cleaning layer, filter layer or adsorbent layer. The ozone-depleting layer is also referred to as sacrificial or ozone protection.

2 shows cross-sectional views of an embodiment of a filter element.

2A shows in cross section a filter element 1 which is in the orientation of 2A from the bottom of RO air is flowed through and clean air RE issues upwards. In comparison to 1 it can be seen that ozone O3 can be present on the clean air side during disinfection intervals. The filter element comprises a pleated or multiply zigzag-folded filter medium, which is constructed as a double-layered and between the layers of activated carbon particles, which are made of coconut shells, for example. The activated carbon particles of the filter layer 3 are configured with regard to the pore distribution and the degree of activation, that a good retention of particular n-butane, toluene, SO ₂ and NO _x takes place.

Sideways are sidebands 11 , For example, provided from a suitable nonwoven filter material, which give the filter element stability. On the fold edges of the pleated filter medium 3 is a sacrificial layer 4 applied. This second location 4 is equipped with activated carbon particles, which are intended only for the purpose of ozone depletion. The second layer therefore serves as an ozone protective layer for the actual filter layer 3 ,

In an alternative embodiment, the ozone protection layer 4 be equipped exclusively or in addition to the activated carbon particles with catalyst materials that decompose ozone efficiently. In the 2 B a detail is shown in more detail. It can be seen that the ozone protection 4 Activated carbon particles 4C and / or catalyst material 4C for example, in lattice form or other suitable geometries between a dihedral material 4A . 4B having.

The material layers can alternatively be formed from simple nonwoven layers. The pleated multiple zigzag folded filter material 3A . 3B serves as a carrier layer for activated carbon particles, which serves as adsorbent for pollutants. The activated carbon particles 3C between the filter fleece sheets 3A . 3B to meet requirements for the retention of noxious gases, for example based on coconut shells.

For activated carbon particles of the sacrificial layer 4 can also cheaper, less well adsorbing coals based on other organic materials such. As peat, wood or hard coal can be used. In particular, for the provided in the sacrificial layer activated carbon particles and lower activation levels of z. 5-10%. There are less requirements for uniform pore size distributions, high specific surface areas, uniform bulk densities, etc.

The layers or layers for the filter element can also be directly connected to each other or placed on each other and then folded into the appropriate shape. It would be conceivable in particular, although the sacrificial layer 4 folded is formed.

3 shows some alternative embodiments of layer sequences for the filter elements. In each case, the sequence of layers or layers to the clean air side or potentially ozone-saturated side is described below for the layer sequence.

3A shows a carrier layer 12 , an adsorbent layer for odor or pollutant retention 3C , a sacrificial layer 4C and another carrier layer 13 , The latter carrier layer 13 is potentially contaminated with ozone. The two carrier layers 12 . 13 can be made of a suitable filter material, for example a dense filter fleece, which retains dirt particles such as dust. The carrier layer 12 , which faces the raw air RO, z. B. have a lower density than the clean air RE facing carrier material 13 , The particles of the actual adsorbent layer, ie activated carbon particles 3C , For example, about surface adhesive or adhesive threads with the carrier layer 12 get connected. Likewise, activated carbon particles can be used 4C which fulfill the function of the ozone victims, suitable for the carrier or filter material layer 13 apply and fix.

3B shows a similar structure as 3A however, between the adsorbent layer 3C and the sacrificial layer 4C a separator 14 made of nonwoven material is provided. Of course, further layers can be added that define the flow resistance of the filter element. At the same time, the addition of additional layers or the omission of filter fleece layers can be used to set the desired retention or filter quality.

3C shows an embodiment in which a carrier layer 12 is provided, to which the adsorbent layer is applied with activated carbon particles for adsorbing contaminants and for cleaning the raw air of odors and harmful gases. On the clean air side is a single carrier or particle layer with activated carbon or catalyst equipment 15 shown. The clean air side position 15 For example, it may comprise a fine grid of catalyst material, which is the actual adsorbent layer combination 12 . 13C is removable. For example, then the location 15 be replaced separately and individually. In this respect, separate change intervals for the actual adsorbent layer 12 . 13 and the ozone donor layer 15 will be realized. The ozone sacrificial layer can also be understood as a carrier layer with activated carbon particles or configured in this way.

Finally shows 3D a further alternative layer sequence for media used in a filter element. It is raw air side, the actual filter layer of a carrier material 12 and the activated carbon particles selected and designed for odor and gas adsorption 3C intended. Furthermore, it is a sacrificial situation 16 provided, which as a nonwoven material with activated carbon and / or Catalyst particles is equipped for ozone depletion. It may also be a grid layer or a foam layer. Finally, on the clean air side, another carrier layer 13 be provided.

The proposed measures for filter elements and filter arrangements make it possible to prevent the destruction of filter-active substances by ozone in an inexpensive and low-cost manner. Since only inexpensive activated carbon or catalyst materials are provided for the sacrificial layer, there is a constant over the entire life period filtering dirt or adsorption of odors and harmful gases through the raw air side filter layer. In particular in the automotive sector, for example for vehicle air conditioning systems, the prescribed invention can be used.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10219966 A1 [0005]
• DE 102004030998 A1 [0006]
• DE 10005197 A1 [0007]

Claims (15)

Filter element ( 1 ), in particular cabin filter for a motor vehicle, which has a first position ( 3 ) with activated carbon particles for adsorbing contaminants and for providing purified indoor air, a filter material layer ( 2 ) and a second layer ( 4 ) with activated carbon particles and / or a catalyst material for the degradation of ozone. Filter element ( 1 ) according to claim 1, wherein the first layer ( 3 ) and / or the second layer ( 4 ) a carrier material ( 3A . 3B . 4A . 4B ) for the activated carbon particles ( 3C . 4C ) and / or the catalyst material. Filter element ( 1 ) according to claim 1 or 2, wherein the filter material layer ( 2 ) and the first layer ( 3 ) form with activated carbon particles an adsorption layer for the retention of odors and contaminants. Filter element ( 1 ) according to one of claims 1 to 3, wherein the first layer ( 3 ) Activated carbon particles, which are made of coconut shells comprises. Filter element ( 1 ) according to any one of claims 1 to 4, wherein the activated carbon particles of the first layer ( 3 ) have a higher degree of activation than the activated carbon particles of the second layer ( 4 ). Filter element ( 1 ) according to one of claims 1 to 5, wherein the second layer ( 4 ) is degraded at least partially in contact with ozone. Filter element ( 1 ) according to one of claims 1 to 6, wherein the second layer ( 4 ) Has activated carbon particles of hard coal, charcoal or olive pits. Filter element ( 1 ) according to one of claims 1 to 7, wherein a specific surface area and / or a pore distribution of the activated carbon particles of the second layer ( 4 ) are adapted for ozone depletion. Filter element ( 1 ) according to one of claims 1 to 8, wherein the second layer ( 4 ) Manganese dioxide, iron oxide, or precious metals as a catalyst material. Filter element ( 1 ) according to one of claims 1 to 9, wherein the first layer ( 3 ), the filter material layer ( 2 ) and the second layer ( 4 ) are interconnected. Filter element ( 1 ) according to one of claims 1 to 10, wherein the second layer ( 4 ) is configured such that without destroying the first layer ( 3 ) or the filter material layer ( 2 ) the second layer can be replaced. Filter element ( 1 ) according to one of claims 1 to 11, wherein the second layer ( 4 ) as one of the first layer ( 3 ) or the filter material layer ( 2 ) Removable grid is formed. Filter arrangement ( 10 ) with a filter element ( 1 ) according to one of claims 1 to 12, a filter element receptacle ( 5 ) for holding the filter element ( 1 ) and an ozone generating device ( 6 ), the second layer ( 4 ) of the filter element ( 1 ) Ozone generator side is arranged. Filter arrangement ( 10 ) according to claim 13, wherein the filter arrangement ( 10 ) is set up such that the ozone generating device ( 6 ) produced by diffusion exclusively to the second layer ( 4 ) is transported. Filter arrangement ( 10 ) according to claim 13, further comprising an evaporator device ( 7 ), and wherein the ozone generating device ( 6 ) between the evaporator device ( 7 ) and the second layer ( 4 ) of the filter element ( 1 ) is provided.

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