DE3740091A1 - FILTER MATERIAL - Google Patents

Abstract

An air filter (20) for the air which is fed to the passenger cabin of a motor vehicle includes a plurality of filter bodies (10) which support one or more catalysts for the catalytic conversion of gas-like harmful substances into less harmful products. The dimensions of the filter bodies are such that they will not escape through a mesh structured wall (28) of the chamber in which the bodies are stored. The surfaces of the filter bodies are preferably corrugated and/or ribbed to provide large surface areas and to minimise contact with adjacent filter bodies. The filter bodies may be produced from thermoplastic material by heating it up in a hot gas stream containing catalyst particles which become embedded in the filter bodies' surfaces. <IMAGE>

Description

The invention relates to a filter material according to the Ober Concept of claim 1.

The ventilation systems of motor vehicles contain in the intake away from the air filter supplied to the passenger compartment Filter out dust from the air. Especially in the stop and-go traffic in the city and in traffic jams are handled through the air supplied to the passenger compartment is also considerably harmful Quantities introduced, so that usually the fresh air supply must be turned off. But also where the The pollutant content of the fresh air supplied is not direct it is evident that pollutants get into it to a greater extent Inside the passenger compartment.

For use in breathing apparatus, filter cartridges are known per se, which not only filter the air mechanically, but also treat it chemically, admix it with oxygen released from oxides, for example, or remove its CO ₂ and water vapor. Such filters, however, consume relatively quickly and are therefore only suitable for short emergencies.

It is also known to reduce the pollutant emissions of internal combustion engines by post-combustion of CO, mitrose gases N O _x and unburned hydrocarbons CH _x using catalysts and thus converting them into more chemically stable, less harmful products. Such catalysts have a monolithic ceramic basic structure, which is coated with a noble metal. Due to their large block-shaped geometry, they are poorly suited for use in the ventilation system of a motor vehicle, since the corresponding air ducts are very angled and their geometry changes greatly from one vehicle to another. In addition, exhaust gas catalysts work at very high gas temperatures, such as are inconceivable for ventilation systems in motor vehicles.

The present invention is therefore intended to provide a filter material be created, which is easy on reception chambers adapts to different geometries and the advantages a catalyst-assisted conversion of gaseous Pollutants in less harmful products also for that Cleaning the passenger compartment of a motor vehicle fresh air supplied usable.

According to the invention, this object is achieved by a filter material according to claim 1.

In the filter material according to the invention is the catalyst material worn by bodies in at least two Directions a dimension of a few millimeters to a few centimeters. In practice, these can Dimensions e.g. are between about 3 mm and 2-5 cm. In In practice, the named dimension of the corpuscles is like this chosen that taking into account the prospect taken admission chambers still considered a filling that can be done without sorting simply by in give the body a fill in the receiving chamber forms with air vents, thereby ensuring at the same time is that the filter material is not meshed or a Grid can escape from the receiving chamber.

By placing the catalyst material on corpuscles orders, can also be carried by different bodies put different catalyst materials together, that would interfere with each other from home. Attached to discrete bodies exist between such different catalyst materials only small point contacts under low pressing force, so that none Deterioration of the catalyst effect of the various  Catalyst materials are to be feared.

Advantageous developments of the invention are in Unteran sayings.

The development of the invention according to claim 4 is in With regard to the most economical use of catalyst materials an advantage.

The development of the invention according to claim 5 is in With a view to easy manufacture of the catalyst material supporting bodies using finely ground powder shaped catalyst material of advantage, which thus is effective with a large surface.

According to claim 6, the base body is made of thermoplastic chemical plastic material, so this reason body not only very cheap and easy in difference Manufacture the smallest geometry, you can also the basic body particularly easy on the surface in the sticky state bring to an inflated hold and stick Ensure catalyst powder.

With the development of the invention according to claim 7 a particularly economical and simple heating the body surface and when admixing the kata Analyzer powder to warm air flow at the same time heating get the catalyst powder, which is a particularly good Attach the individual powder particles to the base body surface guaranteed.

With the development of the invention according to claim 8 ensures a particularly large surface of the body; at the same time there are extensive contacts between neighboring ones Body cleared out.

The developments of the invention according to the claims  9 and 11 serve to reduce the contact areas between neighboring bodies with unsorted pouring of the filter material in a receiving chamber.

With the development of the invention according to claim 10 is achieved when there are two adjacent bodies coincidentally the same geometry but parallel come to rest, also no flat contact between is possible for them. Rather, they remain between the corrugations of the two bodies due to the spacing ribs.

The development of the invention according to claim 12 allows it, various incompatible catalyst materials in the same pourable filter material give. This makes handling considerably easier.

The development of the invention according to claim 13 is with a view to a particularly simple manufacture of the Filter material is an advantage, as there are powder mixtures more easily reproducible than mixtures macroscopic body. It is also microscopic Neighborhood of powder particles from different Catalyst material is sometimes advantageous because it is inexpensive synergistic effects between different Kataly sator materials can result. E.g. can only be a minor one compliant exothermic reaction or a somewhat endothermic reaction from a strongly exothermic reaction in its immediate Neighborhood benefit.

The developments of the invention according to the claims 14-41 give preferred compositions for that of one Body worn catalyst materials.

For the production in very large series it is not complicated geometry of the ventilation system shafts a motor vehicle is also possible, according to formange fit to produce large basic bodies, which then with such  Coated catalyst materials or catalyst mixtures can be, which do not interfere with each other. A corresponding development of the invention is counter state of claim 42.

As far as catalyst materials are mutually negative influence, they will be used according to claim 43 large open-pored bodies on different Base bodies arranged, which then flow behind are arranged in the path of the air to be cleaned.

The development of the invention according to claim 45 is with a view to the largest possible with catalyst mate rial coatable surface of the open-pored body advantageous. Leave open-pore plastic foam parts themselves using inexpensive foam molds easy to manufacture.

The invention will now be described with reference to embodiments play explained with reference to the drawing. In this show:

Fig. 1 shows a longitudinal section through a disc-shaped body of a pourable filter material on a catalyst base;

Fig. 2 is a plan view of the disc-shaped filter body according to claim 1;

Fig. 3 is a section similar to Fig 1 through a modified disc-shaped filter body.

Fig. 4 is a section similar to Fig 1 through a further modified disc-shaped filter body. and

Fig. 5 is a perspective view of an air filter for the ventilation system of a motor vehicle.

In Fig. 1, 10 denotes a disk-shaped filter body, which has a diameter of about 1 cm and a thickness of about 4 mm.

The filter body 10 consists of a molded body made of thermoplastic material 12 and in the upper surface embedded fine particles 14 made of a catalyst material. In practice, the particles 14 can have a grain size of a few 100 μm.

The embedding of the particles 14 is effected in the surface of the base body 12 so that the base body 12 at its surface by blowing or pumping in a warm air current in the tacky state and brings the same time the particles 14 blows against the surface. This is preferably done using a warm air stream to which the particles 14 have been added. This hot air flow is fed to a circulating drum in which the base body 12 is contained. After the base body 12 has cooled again, the particles 14 are then melted to the surface.

As can be seen from FIGS. 1 and 2, the base bodies 12, seen in cross-sectional view, have triangular parallel corrugations 16 to enlarge the surface and the thickness of the filter body 10 .

In order to prevent different filter bodies 10 from being aligned parallel to one another in a bed and then lying directly against one another with their corrugated surfaces, spacer ribs 18 , likewise triangular in cross-section, extend perpendicular to the corrugations 16 , so that the base body 12 has an overall waffle-like structure. The spacer ribs 18 , however, have a slightly lower height than the corrugations 16 , so that adjacent filter bodies 10 align somewhat with one another and get caught together, but passages running parallel to the corrugations 16 definitely remain free.

The corrugations 16 together with the spacing ribs 18 form a stiffening of the base body 12 , so that they need only have a small wall thickness. This is an advantage with regard to the lowest possible weight. Low weight of additional units is generally desirable in vehicle construction, but also keeps the inertial forces low, so that the filter bodies are only subjected to low shock loads during driving. Since the base bodies 12 are injection molded from plastic, they also withstand shocks and vibrations which constantly occur when motor vehicles are being driven.

The flat abutment of filter bodies 10 can also be avoided by mixing filter bodies of different geometry.

So Fig. 3 shows a modified filter body 10 ', which is provided with sinusoidal corrugations 16 ', so that a flat contact with filter bodies 10 is excluded even with the same pitch of the corrugation.

Fig. 4 shows a further modified filter body 10 '', in which corrugations 16 '' are geometrically similar to the corrugations 16 of Fig. 1, but have other gradations. This also makes surface contact between the filter bodies 10 '' and the filter bodies 10 and, of course, Lich also avoided between the filter bodies 10 '' and the filter bodies 10 '.

FIG. 5 shows a filter, designated overall by 20 , for use in the ventilation system of a motor vehicle, which filter is constructed from two cartridges 22 , 24 . The cartridges 22 , 24 each have a housing 26 which is closed on the front and rear by a grid 28 . The mesh size of the grid 28 is slightly smaller than the diameter of the filter body 10 , 10 'and 10 '', so that the latter can be easily poured into the interior of the housing through an opening 30 in the upper wall of the housing 26 . After this filling of the housing, the opening 30 is permanently closed by a lid 32 , wherein an elastically compressible material layer 34 , for example made of foam rubber, can be inserted between the lid and the surface of the bed, which holds the bed under tension.

In the cartridge 22 such filter bodies 10 are filled, which produce gaseous other products from gaseous pollutants, which are carried out of the cartridge 22 with the circulated air. In the cartridge 24 such filter bodies are introduced, which produce solid other products from supplied pollutants, so that the filter bodies are used up over time. Such filter bodies are, for example, those which convert SO _x into elemental sulfur. The cartridge 24 can thus be replaced at intervals, while the cartridge 22 can be used for very long periods of time.

In a modification of the example described above, the filter body 10 can also be formed as spherical balls and their surface covered with catalyst particles in the manner described.

In a further modification of the invention, the filter body 10 can also be pressed massively from catalyst material, the compact then preferably being subjected to a sintering treatment.

Various examples of mixtures of catalyst material which are compatible with one another and can be accommodated on a filter body 10 are given below. All percentages are in percent by weight.

Example 1:
60 percent by weight manganese dioxide (MnO₂)
40 weight percent copper (II) oxide (CuO)

Example 2:
80 percent by weight di-vanadium pentoxide (V₂O₅)
20 weight percent silver oxide (Ag₂O)

Example 3:
15% by weight copper dichloride (CuCl₂)
85% by weight brown dieis trioxide pigment (Fe₂O₃)

Example 4:
5% by weight cobalt (II) molybdate (CoMoO₄)
10 percent by weight iron (III) molybdate (Fe₂ (MoO₄) ₃)
Rest: a bismuth molybdate

Example 5:
10 percent by weight of thorium dioxide (ThO₂)
80 percent by weight zinc oxide (ZnO)
10 weight percent aluminum oxide (Al₂O₃)

Example 6:
40 percent by weight dichromium (III) trioxide (Cr₂O₃)
60 percent by weight dialuminium trioxide (Al₂O₃)

Example 7:
20% by weight cobalt oxide (CoO)
10 percent by weight nickel oxide (NiO)
70% by weight dieis trioxide (Fe₂O₃)

Example 8:
33 percent by weight of iron (III) molybdate (Fe₂ (MoO₄) ₃)
33% by weight cobalt (II) molybdate (CoMoO₄)
33% by weight bismuth (III) molybdate (Bi₂ (MoO₄) ₃)

Example 9:
80 weight percent aluminum oxide (Al₂O₃)
6.6 weight percent silver (Ag)
6.6 wt% platinum (Pt)
6.6 percent by weight rhodium (Rh)

Other examples of catalyst materials for the filter body 10 are particles of alpha alumina, which are provided on their surface with a thin layer of precious metal. This surface covering can be done, for example, by vacuum deposition, sputtering or the like.

Example 10:
Alpha aluminum oxide vaporized with 1 percent by weight ruthenium (Ru)

Example 11:
Alpha aluminum oxide vaporized with a total of 2 percent by weight with equal proportions of metallic platinum (Pt) and rhodium (Rh)

Example 12:
Particles of alpha aluminum oxide on the surface are vaporized with two percent by weight of platinum (Pt) and ruthenium (Ru) in equal proportions

Other suitable catalyst materials for the filter body 10 include pure substances:

Example 13:
Dichromium (III) trioxide (Cr₂O₃)

Example 14:
Titanium (IV) vanadate (Ti₃ (VO₄) ₄)

Example 15:
Diantimone tetroxide (Sb₂O₄)

Combination filters can be Filter materials by combining different filters body with catalyst materials according to the examples above Just put together 1-15. Below are some preferred examples of such filter body mixtures given:  

Example A:
1/3 filter body according to Example 1
1/3 filter body according to example 2
1/3 filter body according to example 3

Example B
1/4 filter body according to Example 1
1/4 filter body according to example 3
1/4 filter body according to example 4
1/4 filter body according to example 13

Example C
1/4 filter body according to Example 1
1/4 filter body according to example 4
1/4 filter body according to Example 5
1/4 filter body according to example 13

Example D
1/3 filter body according to example 6
1/3 filter body according to Example 7
1/3 filter body according to example 10

Example E:
1/3 filter body according to Example 8
1/3 filter body according to example 10
1/3 filter body according to Example 11

Example F
1/4 filter body according to example 6
1/4 filter body according to Example 9
1/4 filter body according to example 10
1/4 filter body according to Example 11

Example G
1/4 filter body according to example 2
1/4 filter body according to example 4
1/4 filter body according to example 8
1/4 filter body according to example 12

Example H
1/5 filter body according to example 6
1/5 filter body according to Example 9
1/5 filter body according to Example 10
1/5 filter body according to Example 11
1/5 filter body according to Example 14

Example I:
1/4 filter body according to example 8
1/4 filter body according to example 10
1/4 filter body according to Example 11
1/4 filter body according to Example 15

In a modification of the exemplary embodiments described above, cartridges of a combi filter, which have different catalyst materials carried by a base body, can also be produced from a monolithic filter block, which is then inserted into an outer housing in a manner similar to that for a pourable filter material with reference name above Fig. 5 described in more detail.

Such a monolithic filter block can e.g. by Foaming polyurethane in such a foam form generated, which is the geometry of a cartridge housing corresponds. Such foam shapes can be proportionate produce moderately inexpensive even for complicated geometries, so that you can also use appropriate filter inserts on curvatures and sections having cross-sectional changes of Air ducts of the ventilation system of the motor vehicle under can bring.

The catalyst material can be the plastic to be foamed even before foaming or in the course of foaming (However, in the case of pores which have already formed, it has not yet solidified Plastic material) can be added. Has the open pore Basic body very large pores, you can see the coating even after the plastic material has hardened Applying a suspension of the catalyst mixture or apply by immersion in such a suspension.

Claims (45)

1. Filter material based on catalyst, in particular for cleaning the air supplied to the passenger compartment of motor vehicles, characterized in that at least one catalyst material is carried by bodies ( 10 ), the dimension of which in at least two directions is a few millimeters to a few centimeters. 2. Filter material according to claim 1, characterized in that the bodies ( 10 ) consist of pressed catalyst particles. 3. Filter material according to claim 2, characterized in that the catalyst particles are sintered together. 4. Filter material according to claim 1, characterized in that the bodies ( 10 ) consist of a pre-geometry base body ( 12 ) and a coating ( 14 ) made of the catalyst material. 5. Filter material according to claim 4, characterized in that on the base body ( 12 ) powdery catalyst material is inflated in the sticky state. 6. Filter material according to claim 5, characterized in that the base body ( 12 ) are made of thermoplastic material and have been brought into the sticky state by heating. 7. Filter material according to claim 6, characterized in that the base body ( 12 ) have been heated by a hot air stream, which is preferably also admixed with the catalyst powder. 8. Filter material according to one of claims 1-7, characterized in that the bodies ( 10 ) have corrugations ( 16 ). 9. Filter material according to claim 8, characterized in that perpendicular to the corrugations ( 16 ) spacer ribs ( 18 ) on the body ( 10 ) are provided. 10. Filter material according to claim 9, characterized in that the spacer ribs ( 18 ) have a smaller height than corrugations ( 16 ). 11. Filter material according to one of claims 8-10, characterized in that among the bodies ( 10 ) are those with different pitch and / or different geometry of the corrugations ( 16 ). 12. Filter material according to one of claims 1-11, characterized in that different catalyst materials which are necessary together for a complete removal of CO, NO _x and CH _x and SO _x from air, but adversely affect each other, for example poison each other, on different bodies ( 10 ) are arranged. 13. Filter material according to one of claims 1-12, characterized in that at least one of the catalyst materials is a mixture of such catalysts, which by themselves either for the oxidation of CO, the oxidation of NO _x , the reduction of SO _x or the catalytic combustion of CH _{x are} particularly suitable, but do not interfere with each other, are arranged together on a body ( 10 ). 14. Filter material according to claim 13, characterized in that the catalyst mixture contains MnO ₂ and CuO. 15. Filter material according to claim 14, characterized in that the proportion of MnO₂ about 60 percent by weight and  the proportion of CuO is about 40 percent by weight. 16. Filter material according to claim 13, characterized in that a mixture component V ₂ O ₅ and a second mixture component is Ag ₂ O. 17. Filter material according to claim 16, characterized in that the proportion of V ₂ O _{5 is} approximately 80 percent by weight and the proportion of Ag ₂ O is approximately 20 percent by weight. 18. Filter material according to claim 13, characterized in that one of the mixture components comprises CuCl ₂ and a second of the mixture components Fe ₂ O ₃ . 19. Filter material according to claim 18, characterized in that the proportion of CuCl _{2 is} about 15 weight percent and the proportion of Fe ₂ O _{3 is} about 85 weight percent. 20. Filter material according to claim 13, characterized in that a mixture component CoMoO ₄ , a second mixture component Fe ₂ (MoO ₄ ) ₃ and a third mixture component Bi ₂ (MoO ₄ ) ₃ . 21. Filter material according to claim 20, characterized in that the proportion of CoMoO _{4 is} about 5 percent by weight and the proportion of Fe ₂ (Mo ₄ ) _{3 is} about 10 percent by weight, the remaining portion is Bi ₂ (MoO ₄ ) ₃ . 22. Filter material according to claim 13, characterized in that one of the mixture components ThO ₂ , a second of the mixture components ZnO and a third mixture component is Al ₂ O ₃ . 23. Filter material according to claim 22, characterized in that the proportion of ThO _{2 is} approximately 10 percent by weight, the proportion of ZnO is approximately 80 percent by weight and the proportion of Al ₂ O _{3 is} approximately 10 percent by weight. 24. Filter material according to claim 23, characterized in that one of the mixture components is Cr ₂ O ₃ and a second of the mixture components is Al ₂ O ₃ . 25. Filter material according to claim 24, characterized in that the proportion of Cr ₂ O _{3 is} approximately 40 percent by weight and the proportion of Al ₂ O _{3 is} approximately 60 percent by weight. 26. Filter material according to claim 13, characterized in that a mixture component is CoO, a second mixture component NiO and a third mixture component Fe ₂ O ₃ . 27. Filter material according to claim 16, characterized in that the proportion of CoO is approximately 20 percent by weight, the proportion of NiO is approximately 10 percent by weight and the proportion of Fe ₂ O _{3 is} approximately 70 percent by weight. 28. Filter material according to claim 13, characterized in that one of the mixture components comprises alpha-Al ₂ O ₃ , which is vapor-coated with Ru on the surface. 29. Filter material according to claim 28, characterized in that the proportion of Ru is about 1 percent by weight. 30. Filter material according to claim 13, characterized in that one of the components is alpha-Al ₂ O ₃ , which is coated with Pt and Rh on the surface. 31. Filter material according to claim 30, characterized in that Pt and Rh were evaporated in equal parts by weight are. 32. Filter material according to claim 30 or 31, characterized characterized in that the total proportion of Pt and Rh is about 2 percent by weight.   33. Filter material according to claim 13, characterized in that one of the mixture components alpha-Al ₂ O ₃ , a second mixture component Ag, a third mixture component Pt and a fourth mixture component Rh. 34. Filter material according to claim 33, characterized in that the proportion of alpha-Al ₂ O _{3 is} approximately 80 percent by weight and the proportion of noble metals is approximately 20 percent by weight. 35. Filter material according to claim 33 or 34, characterized records that the weight fractions of Ag, Pt, Rh about are the same size. 36. Filter material according to claim 13, characterized in that one of the mixture components comprises alpha-Al ₂ O ₃ , which is surface-evaporated with Pt and Ru. 37. Filter material according to claim 36, characterized in that that the weight proportions of Pt and Ru are about the same are great. 38. Filter material according to claim 36 or 37, characterized characterized in that the total weight proportion of the noble metals is about 2%. 39. Filter material according to one of claims 1-12, characterized in that one of the catalyst materials is Cr ₂ O ₃ . 40. Filter material according to one of claims 1-12, characterized in that one of the catalyst materials is Ti ₃ (VO ₄ ) ₄ . 41. Filter material according to one of claims 1-12, characterized in that one of the filter materials is Sb ₂ O₄. 42. Filter block based on catalyst, in particular for cleaning the air supplied to the passenger compartment of a motor vehicle, characterized in that various catalyst materials, which together are necessary to completely remove CO, NO _x and CH _x and SO _x from air, adversely affect one another , eg poison each other, are arranged on various large open-pored bodies. 43. Filter block on a catalyst basis, in particular for cleaning the air supplied to the passenger compartment of a motor vehicle, characterized in that at least one open-pore base body carries a mixture of such catalysts, which on their own either for the oxidation of CO, the oxidation of NO _x , the reduction of SO _x or the catalytic combustion of CH _{x are} particularly suitable, but do not affect each other. 44. Filter block according to claim 43, characterized by a catalyst mixture according to one of the claims 14-41. 45. Filter block according to one of claims 42-44, characterized characterized in that the open-pored body Open-pore plastic foam part is, in particular open-pore foamed polyurethane.