Indoor air filter module and filter assembly

Abstract

The invention relates to an indoor air filter module (1) comprising a particle filter element (2), an adsorption filter element (3) and a frame (4) surrounding the particle filter element (2) and the adsorption filter element (3). The frame (4) has a radially protruding sealing flange (5), the particle filter element (2) comprising a folded pack formed of a plurality of layers of a filter material (15) folded in a zigzag shape, at least one layer (2B) comprising an aerosol separation filter medium. The particle filter element (2) comprises a first layer (2A) on the inlet side and a second layer (2B) on the outlet side, folded on top of each other to form a folded pack. The adsorption filter element (3) comprises at least one shaped body (3A-3E) configured as a honeycomb body and adsorbing at least hydrocarbons. The sealing flange (5) is arranged laterally around the adsorption filter element (3) at its circumferential outer wall (14).

Description

[Technical field]

[0001] The present invention relates to a filter element, in particular an interior air filter module for filtering air supplied to the cab of a vehicle, agricultural machine, construction machine, or work machine, and further to a filter assembly for and comprising such a filter element. [Background technology]

[0002] A filter module or filter insert is generally understood as an insert consisting of at least one filter element made of a filter medium, usually a structure for carrying or supporting the filter medium, and in most cases a seal, which is arranged replaceably as a unit in a filter housing. Each filter medium generally has a limited service life. For this reason, the filter module needs to be replaced periodically as a unit.

[0003] Nowadays, the air entering the vehicle interior is as completely free of pollutants as possible. These can be, for example, particulate matter, pollen, soot, harmful gases, aerosols, etc. Filtration of such pollutants is particularly important in applications where these substances are present in high concentrations in the ambient air due to the use of plant protection agents or liquid fertilizer application devices. For this purpose, various filter media are available. Typically, for example, particle filters, activated carbon filters, HEPA filters, etc. are used. These are combined in different layers and in different arrangements in order to obtain the desired filtering effect on the interior air.

[0004] EP 3520878 A1 discloses a filter module for filtering indoor air with three filter layers, which are arranged in a common frame assembled from extruded profile strips. One of the filter layers consists of an adsorption filter configured as a honeycomb body, the other two filter layers consist of particle filters. The particle filter layers consist of separate filter bellows through which fluids can flow in series, one of the filter bellows consisting of HEPA filter material. The profile strips of the frame hold the filter layers on the inside, while on the outside the filter module is hermetically fixed by the frame to the housing.

[0005] The filter module of EP 3520878 A1 comprises a circumferentially extending sealing flange formed on the profile strip, which projects radially outward in the region of the two particle filter elements. Since honeycomb bodies are generally massive equipment parts, the position of the sealing flange disclosed in this document is technically disadvantageous in view of the effects of vibration loads. The profile strip also has two circumferentially extending collar parts which project inward and respectively support two of the filter layers. This construction, in combination with the arrangement of the particle filter layers which are separate filter bellows, requires a relatively large installation space in the axial direction.

[0006] The demand for high integration of the various mechanical components and long filter life results in conflicting goals for the layout and construction of the interior air filter. For high integration, a very compact construction and a filter volume as small as possible are advantageous. On the other hand, a long service life usually requires a large filter volume. Furthermore, a safe fixation and stability of the filter module must be guaranteed, even against vibrations and shocks during vehicle operation. In particular, many filter modules of the prior art do not guarantee stability against vibrations.

[0007] It is therefore desirable to provide a filter module that operates reliably even under the influence of vibrations during vehicle operation and requires a reduced installation space. Summary of the Invention

[0008] Against this background, the present invention aims to provide an improved filter element or filter module.

[0009] Therefore, a filter module, in particular a room air filter module, is proposed which comprises a particle filter element, an adsorption filter element and a frame which circumferentially surrounds the particle filter element and the adsorption filter element and has a radially projecting sealing flange.

[0010] In this regard, the particle filter element preferably comprises a folded pack formed from a plurality of layers of filter media folded in a zigzag manner.

[0011] In particular, at least one layer comprises an aerosol separation filter medium.

[0012] The adsorptive filter element preferably comprises a shaped body for adsorbing at least hydrocarbons, the shaped body can also be configured to adsorb other harmful gases, such as NH3 and / or H2S.

[0013] The sealing flange preferably laterally surrounds or is arranged to surround the adsorptive filter element at its circumferentially extending outer wall. A seal can be arranged on the sealing flange. The seal can in particular be injection molded on the sealing flange or can be attached to the sealing flange as a separate part. Alternatively or additionally, the seal can comprise a first part arranged on a first axial surface of the sealing flange and a second part arranged on a second axial surface of the sealing flange facing away from the first axial surface of the sealing flange. In this way, in the installed state of the filter module, an inner sealing of the untreated air area against the clean air area and an outer sealing against the environment can be achieved. In other words, the seal can be a biaxial seal.

[0014] Such an arrangement of the sealing flange is advantageous in the operation of the filter module according to the invention, since the sealing flange is arranged in the axial direction as close as possible to the center of mass of the filter module, which increases the reliability of the filter module, in particular since the risk of the frame being damaged by forces due to vibration loads is reduced.

[0015] In particular, the particle filter element and the adsorptive filter element are arranged in the filter module according to the invention in such a way that the fluids can flow in series. In particular, the particle filter element and the adsorptive filter element are arranged upstream of the adsorptive filter element in such a way that the air flow passing through the filter module according to the invention first flows through the particle filter element and then through the adsorptive filter element. This is advantageous in that the air from which the particles have been removed flows through the adsorptive filter element, and the pores and channels of the adsorptive filter element are not clogged by the particles, thereby improving the adsorptive performance of the adsorptive filter element, especially taken into account over time.

[0016] The proposed filter module allows for a compact construction for use in applications with limited installation space and, in particular, the frame configuration with sealing flanges in the area of ​​the adsorption filter elements ensures a reliable installation and reliable filtering even in the face of vibrations during operation.

[0017] In this context, the interior air filter module is suitable as a replaceable part for the interior air filter of the cab of agricultural machines or working machines, in particular those equipped with spraying or scattering devices for plant protection agents or fertilizers, and can be mounted in a filter housing fixed to the vehicle.

[0018] Each layer of the filter medium used in the particle filter element can be configured in a folded or pleated form. For example, zigzag or W-fold pleats are known. The filter medium can be embossed and then folded at the embossed edge at an acute angle to form the folded edge. Starting from a flat filter sheet material, the corresponding shape can be formed.

[0019] Each filter medium is, for example, a woven filter cloth, a filter fabric, or a nonwoven filter cloth. In particular, the filter medium can be manufactured by a spunbonding method or a meltblown method. Furthermore, the filter medium can be felted or needled. The filter medium can include natural fibers such as cotton, synthetic fibers such as polyester, polyphenylene sulfide, or polytetrafluoroethylene. During processing, the fibers can be oriented obliquely and / or transversely to the machine direction.

[0020] In addition, an adsorbent such as activated carbon may be contained in or between the layers. Furthermore, the filter medium may have antibacterial and / or antiallergic effects. Examples of antibacterial substances include zinc pyrithione and silver microparticles, and examples of antiallergic substances include polyphenols.

[0021] The corresponding filter module serves to filter a fluid, i.e. a gaseous medium and / or a liquid medium, for example air, where the gaseous medium or air also includes a mixture of gas or air with solids and / or a mixture of gas or air with liquids. For example, an air conditioning system may be provided with a filter element.

[0022] In particular, open-type filter media have a filtration rate of 3,000 l / m (determined in accordance with ISO 9237 at 200 Pa) at a filtration speed of 0.05 to 0.30 m / s on the surface of the filter media. 2 The filter can be configured to remove particles of test dust A4 according to ISO 12103-1 from the air flow with a permeability of more than 1.5 mm. The determination of the filtration characteristic value can be carried out, for example, according to 14269-4.

[0023] Particularly high-separation filter media have a filtration rate of 170 l / m (determined in accordance with ISO 9237 at 200 Pa) at a filtration rate of 0.05 to 0.30 m / s on the filter media surface. 2 s from the air flow. The determination of the filtration characteristic values ​​can be carried out, for example, in accordance with DIN 14269-4.

[0024] In some embodiments, one of the layers of the particle filter element comprises an aerosol-separating particle filter medium of filter class H13 or H14 according to DIN EN1822-1. In other words, at least one of the layers of the particle filter element may comprise a HEPA filter medium. This may involve the use of a plastic material or a nonwoven material of glass fiber. In some embodiments, the downstream aerosol filter layer is formed from a HEPA aerosol medium made of ePTFE.

[0025] The particle filter element comprises a first layer on the inlet side and a second layer on the outlet side, which are folded or pleated together on top of one another to form a folded pack, where "on top of one another" is understood to include not only direct contact but also indirect contact via further structures, such as adhesive layers or adhesive tracks.

[0026] The first layer on the inlet side can hold the maximum amount of dust, while the second layer on the outlet side can be configured as an aerosol medium, which reduces clogging of the aerosol layer with particles.

[0027] As the first layer, also called pre-filter layer, for example, an epoxy-impregnated cellulose filter medium is used. Preferably, the cellulose filter medium has a density of 80 to 140 g / m 2 , preferably 100 to 120 g / m 2 In a preferred embodiment, the filter medium has a maximum pore size in the range of 30-40 μm and / or a mesh size of about 100-400 l / m2, measured at a pressure difference of 200 Pa (hereinafter preferably measured according to DIN EN ISO 9237). 2 s, preferably 200 to 300 l / m 2 It has an air permeability of .s. This can protect the subsequent layers from dust accumulation and ensure their function. In a further embodiment, the impregnation amount, i.e., the weight ratio of the impregnating agent to the basis weight of the filter medium, is 15 to 30%.

[0028] As the nonwoven fabric filter material of the prefilter layer, a combination of a spunbond layer and a meltblown layer (meltblown synthetic fiber nonwoven fabric) can be preferably used. Each of these layers can be made of polyamide (PA), polyester (PES) or polypropylene (PP). The nonwoven fabric filter material has a density of 60 to 140 g / m 2 , preferably 80 to 120 g / m 2 and / or a thickness in the range of 0.5 to 1 mm, particularly preferably 0.5 to 0.8 mm. 2s, particularly preferably 1,200 to 1,800 l / m 2 It is even more preferable that the material has an air permeability of 0.5 to 1.0 s.

[0029] In some embodiments, the prefilter layer has a degree of separation of 99% for test dust A2 or A4 according to ISO 12103-1, particularly according to ISO 5011.

[0030] In a preferred embodiment, the prefilter layer has a thickness of 75 to 125 g / m 2 Preferably, the filter material of the prefilter layer has a basis weight of 100 to 200 l / m at a pressure difference of 200 Pa. 2 It has an air permeability of s.

[0031] The second layer, also called fine filter layer, can be designed as a HEPA bellows layer. In one embodiment, a filter medium with glass fibers in a glass fiber layer in an initially unfolded state is used as the fine filter layer. In this connection, for example, a glass fiber nonwoven fabric or glass fiber paper can be used. It is also preferable that a cover layer made of a spunbond nonwoven fabric is laminated on one or both sides. This allows, in particular, mechanical protection of the generally sensitive glass fiber medium. This is particularly advantageous when the glass fiber layer is folded, since it can protect the medium from damage due to folding, which can lead to localized leaks and cracks. Moreover, such a cover layer serves to improve the mechanical stability of the fine filter layer.

[0032] In one embodiment of the fine filter layer, the glass fibers have a fiber diameter in the range of 800 nm to 5 μm. Preferably, 90% of the fibers have a fiber diameter in this range. Preferably, the fiber diameter is substantially within the fiber diameter range throughout. Preferably, the average fiber diameter is within the above range. The fiber diameter can be measured, for example, according to the method described in DE 102009043273 A1 or US 2011 / 0235867 A1. Preferably, the filter material of the fine filter layer has a fiber weight of 60 to 100 g / m2 , particularly preferably 75 to 90 g / m 2 The glass fiber layer has a basis weight of 0.2 to 1 mm, and particularly preferably 0.3 to 0.6 mm. Particularly preferably, a glass fiber layer is used that generates a resistance in the range of 300 to 600 Pa, preferably 400 to 500 Pa, at an inflow velocity of 7.5 cm / s. The air permeability (permeability) is 25 to 45 l / m at a pressure difference of 200 Pa. 2 The pressure loss at a flow rate of 5.3 cm / s is preferably in the range of 200 to 700 Pa, particularly preferably 450 to 600 Pa, or 270 to 480 Pa. The pore size is preferably in the range of 5 to 12 μm, particularly preferably 8 to 10 μm.

[0033] Instead of glass fibers, synthetic fibers can also be used in the fine filter layer. In one embodiment, such synthetic HEPA media are used instead of the glass fiber media described above. As materials, for example, polyester or polypropylene or polyamide can be used. The fiber layer is preferably designed as a nonwoven fabric and can be manufactured, for example, by electrospinning, meltblowing, etc. Preferably, an electret medium is used. Depending on the material properties of the synthetic filter medium, the cover layer and the protective layer can be omitted. Preferably, the basis weight is, for example, 80 to 160 g / m 2 , preferably 80 to 120 g / m 2 For example, a meltblown polyester nonwoven layer having a thickness of about 0.4-1 mm is used. More preferably, this layer is applied on a carrier layer. The carrier layer can be, for example, a plastic support grid or a spunbonded nonwoven. Further properties correspond to those of the fine filter layer with glass fibers described above.

[0034] The particle filter element has an aerosol transmission, measured in particular in accordance with EN 15695, of ≦0.05%.

[0035] Compared to the prior art, this structure of integrated pre-filter and fine filter layers in a particle filter element offers the advantage that the required installation space in the axial direction can be significantly reduced while the filtering performance is substantially maintained: compared to the embodiment using separate filter bellows as pre-filter and fine filter layers, the advantage in the installation space in the axial direction reaches up to 50%.

[0036] In some embodiments, the particle filter element comprises a frame circumferentially surrounding the folded pack, including side bands attached to the pleats of the folded filter media and a headband attached to the end pleats of the folded pack.

[0037] Specifically, the side bands are bonded to the pleats to form a seal, and the headband also forms a hermetic seal.

[0038] The pleat spacing of the folded pack is, for example, 3 to 5 mm, and the pleat height is 16 to 30 mm. In some embodiments, there may be 100 to 150 pleats.

[0039] In some embodiments, the frame is manufactured from a plastic material, in particular a rigid plastic material, and the partial filter elements (particle filter elements and adsorption filter elements) for forming in particular the indoor filter module are in direct abutment with one another and are sealingly connected to one another by the frame.

[0040] In particular, the frame can be provided as an injection-molded plastic frame, which can accommodate the partial filter elements that are prefabricated and glued or welded into the frame, or alternatively, the frame can be designed as an overmolded frame, in which the partial filter elements are placed in a mold and the frame is injection-molded around them, so that on hardening the respective material is permanently connected to the partial filter elements.

[0041] It is further contemplated that the frame may be formed from a potting compound containing polyurethane (PUR) or other cast polymers, in particular expanded polyurethane, ie polyurethane foam.

[0042] In some embodiments, the indoor filter module further comprises an auxiliary frame that at least partially laterally surrounds and fixes the particle filter element and the adsorption filter element to one another, which allows for improved handling of the semi-finished parts and components of the filter module and simplifies the manufacture of the indoor filter module. The auxiliary frame can be connected to the frame, in particular by gluing or foam molding. Alternatively or additionally, the particle filter element and the adsorption filter element can be glued to the auxiliary frame.

[0043] In particular, the auxiliary frame can completely surround the particle filter element and the adsorptive filter element in the circumferential direction. In particular, the auxiliary frame can include or consist of a nonwoven material. The nonwoven material of the auxiliary frame can in particular be thicker than the filter medium of the particle filter element. Alternatively or additionally, the nonwoven material of the auxiliary frame can have a higher bending stiffness than the filter medium of the particle filter element.

[0044] In some embodiments of the room filter module, an intermediate filter layer is further arranged on the outlet side of the adsorption filter element. The intermediate filter layer is in particular formed as the last filter stage on the outlet side of the inventive filter module. This makes it possible to prevent, for example, particulate adsorbent from escaping in the event of undesirable mechanical or abrasive forces. This is important in order to prevent the adsorbent from escaping from the honeycomb body to the clean side and reaching the room during operation. Furthermore, the intermediate filter layer prevents the adsorbent from being "lost" from the adsorption filter element and ensures that the adsorption capacity of the filter module is maintained over its planned service life.

[0045] In some embodiments, the adsorptive filter element includes a plurality of molded bodies connected to one another, particularly by a thermosetting potting compound.

[0046] As shaped bodies there come into consideration in particular honeycomb bodies, as described in EP-A-2 946 827 (incorporated by reference).

[0047] At least one formed body in some embodiments is at least partially formed of a ceramic material, an activated carbon material, an ion exchanger material, a molecular sieve material, a zeolite material, an organometallic support material, and / or a metallic material.

[0048] Thus, as materials for the shaped body, in particular the materials disclosed in paragraphs 0006 to 0012 of EP-A-2 946 827 come into consideration. The shape and the internal structure of the shaped body are designed in particular as described for the honeycomb bodies in EP-A-2 946 827 (see, for example, paragraphs 0014 to 0031 of EP-A-2 946 827).

[0049] The use of honeycomb bodies as adsorptive filter elements has the advantage that the flow resistance is very low compared to known embodiments of adsorptive filter elements, such as folded, stacked or rolled layers of filter media with adsorbent or bulk filling (so-called combined filter media). Furthermore, honeycomb bodies can provide very high adsorption capacities, so that they can be used for quite long periods before gas breakthrough occurs.

[0050] The honeycomb body is in particular formed as an extrusion body consisting of channels and walls arranged between them. The channels penetrate the honeycomb body and are in particular open at both ends, so that the air to be filtered can flow between the inlet and the outlet. The resulting pressure loss is mainly due to the friction effect of the air on the walls of the channels, and no clogging effect occurs as in "conventional" filter media.

[0051] In this respect, the use of honeycomb bodies is already surprising to those skilled in the art and cannot be compared to alternative adsorptive filters, especially layers of combined filter media folded, stacked or rolled.

[0052] In some embodiments, the honeycomb body has a channel wall thickness of 200 μm to 400 μm. Such channel dimensions are advantageous for obtaining a honeycomb body with a large number of channels, which has a large contact surface for the air to be filtered.

[0053] The number of channels in the honeycomb body is between 40 and 100 per square centimeter. This channel density has been found to be advantageous for achieving high adsorption capacity and minimal pressure loss.

[0054] The honeycomb body may be made from or may contain activated carbon. Activated carbon can be easily extruded to form the honeycomb body in the form of a paste or as part of a paste which, in addition to activated carbon particles, also contains at least a suitable binder material. The proportion of activated carbon in the honeycomb body is, for example, 50-80% by weight. When producing a honeycomb body, the pasty starting material after extrusion is first subjected to one or several drying steps and then sintered at high temperature. In this case, the binder contained in the paste is pyrolyzed, leaving behind the porous structure of the activated carbon. The aforementioned paste composition has been found to be advantageous, on the one hand, in order to be able to introduce a sufficient amount of activated carbon into the honeycomb body and, on the other hand, to ensure the mechanical stability of the honeycomb body.

[0055] In some embodiments, the honeycomb body includes an impregnant to improve separation of non-hydrocarbon harmful gases, in particular, the impregnant can improve separation of NH3 and / or H2S.

[0056] In some embodiments, the particle filter element, the adsorptive filter element, the molding and / or the indoor air filter module itself are each configured in a cubic shape, which can be advantageously combined with the filter module and allows for efficient use of the installation space.

[0057] Furthermore, especially in the case of a cube-shaped outline, mirror symmetry exists with respect to a given plane passing through the filter module, which allows a favorable mass distribution of the filter module. It has been found to be advantageous to adjust the center of gravity of the filter module with respect to the attachment or mount of the filter housing so as to reduce only the mechanical loads due to vibrations and movements of the vehicle.

[0058] In some embodiments, the sealing flange defines a sealing surface and is positioned such that the sealing surface extends through an interior of the molding.

[0059] For example, a protruding sealing flange circumferentially surrounds the circumferential side of the frame as a protruding flat collar, optionally with one or more seals following the contour of the flange, to be retained between corresponding sealing surfaces of the housing, separating the untreated air region from the clean air region.

[0060] The sealing surface can be understood as a spatial plane in which the sealing flange or an additional seal is located in the installed state. Such a (virtual) plane divides the filter module into a first part and a second part. Each of the two parts has a mass proportion, the sum of these two mass proportions being the total mass of the filter module.

[0061] Thus, in some embodiments, the sealing flanges define corresponding sealing surfaces dividing the indoor air filter module into a first part and a second part, the sealing flanges being arranged such that the ratio between the mass of the first part of the indoor air filter module and the mass of the second part of the indoor air filter module has a predetermined value. This value is, for example, between 0.5 and 1.5, preferably between 0.6 and 1.4, particularly preferably between 0.8 and 1.2. More preferably, this value is between 0.9 and 1.1. In an embodiment with a value of 1.0, the centre of mass of the indoor air filter module is located at the sealing surface.

[0062] With regard to the axial and radial directions of a filter module, "axial" is understood as the flow direction. For example, the axial direction is perpendicular to the inlet or inlet face of a cubic-shaped filter module. "Radial" is understood in particular as the normal direction to the side or side wall of the frame or to the side of a cubic-shaped filter element.

[0063] In addition to the filter module, a filter assembly is proposed which includes a filter housing which houses at least one filter module as described above or below, the filter housing having first and second seal portions which follow the contours of the seal flanges and / or seals.

[0064] In some embodiments, the sealing flange and / or seal is axially compressed between the two housing portions when the filter module is intended to be placed within the filter housing.

[0065] The filter assembly is preferably designed for filtration according to category 4 in accordance with DIN EN 15695-1. The use of the filter module as an interior air filter in the cab of agricultural and working machines, such as tractors, combines, harvesters, in particular equipped with spraying or spreading devices for plant protection agents or fertilizers, is therefore proposed.

[0066] The norms and standards set forth above and below are understood to be current as of the filing date of this application.

[0067] Further embodiments of the invention include not expressly mentioned combinations of the features disclosed above or below with respect to the exemplary embodiments, and the person skilled in the art will be able to add individual aspects as improvements or supplements to each basic form of the invention.

[0068] Further embodiments of the invention are the subject of the dependent claims as well as the embodiments of the invention described below.The invention is explained in more detail below with the aid of embodiments and with reference to the attached figures. [Brief description of the drawings]

[0069] [Figure 1] 1 is a partial vertical cross-sectional view showing an embodiment of an indoor air filter module of the present invention. [Diagram 2] 1 is a cross-sectional view of an embodiment of an indoor air filter module. [Diagram 3] FIG. 3 is an exploded perspective view of the indoor air filter module of FIGS. 1 and 2. [Figure 4] FIG. 4 is a perspective cross-sectional view of an embodiment of a filter assembly including the indoor air filter module of FIGS. 1 to 3. [Diagram 5] FIG. 5 is a cross-sectional view of the filter assembly of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] In the drawings, identical or functionally identical elements are provided with the same reference symbols unless otherwise stated.

[0071] In the following, an embodiment of the filter module as an interior filter module for the air supply of the cab of an agricultural vehicle and its use in a corresponding filter assembly are described. In figures 1 to 3 the interior air filter module is shown from different angles, while in figures 4 and 5 the interior air filter module arranged in a filter housing is shown as a filter assembly for realizing an interior filter of category 4 of the European standard DIN EN 15695. For the protection of the driver, in addition to dust, mainly airborne aerosols and gaseous pollutants are prevented from entering the cab.

[0072] In the flow direction L (see top to bottom direction in FIG. 3), the room filter module 1 comprises a particle filter element 2 corresponding to filter class H13 or H14 according to DIN EN 1822. A HEPA filter (suspended particle filter or high efficiency particulate air filter) is thus provided which passes only gaseous air pollutants. The particle filter element 2 consists of a folded pack formed of two layers of flat filter material folded in a zigzag manner and a circumferentially extending edge formed by two head bands 12A and two side bands 12B. This gives the particle filter element 2 a flattened cubic shape.

[0073] The folded pack or folded bellows is shown in FIG. 1 with a partial enlarged view. The first layer 2A (prefilter layer) and the second layer 2B (fine filter layer) of the filter medium 3 are loosely arranged relative to each other in the initial stage of manufacture and are then folded in a zigzag pattern. The side bands 12B are glued to maintain the pleated shape. The end pleats are each provided with a headband 12A, resulting in an easy-to-handle partial filter element 2. The prefilter layer 2A is made of a nonwoven fabric made of a synthetic plastic material such as PET, PP or PC. The fine filter layer 2B is made of an ePTFE material. The composite filter medium of the layers 2A and 2B has an air permeability of about 87 l / m. 2 s. Fig. 1 shows a partial longitudinal section along the length direction of the rod-shaped cube of the indoor filter module 1 shown in Fig. 3, and Fig. 2 shows a cross section perpendicular to the length direction LO.

[0074] Downstream of the particle filter element 2, an adsorption filter element 3 is arranged, which is formed from honeycomb bodies 3A-3E. The cubic honeycomb bodies 3A-3E are hermetically fixed to one another by a potting compound. During operation of the indoor filter module 1, pre-purified air passes through each honeycomb body 3A-3E, where at least hydrocarbons are adsorbed. For example, the honeycomb bodies 3A-3E described in EP 2 946 827 A1 are used.

[0075] The particle filter element 2 and the adsorption filter element 3 are held together by an auxiliary frame 7 on four sides. The lower side of the particle filter element 2 and the upper side of the adsorption filter element 3 are in contact with each other, and the two partial filter elements 2, 3 are held together by the auxiliary frame 7, which is made of a nonwoven fabric or a side band material and is laterally attached to the side band 12B and the head band 12A, as well as to the outer surfaces of the honeycomb bodies 3A to 3E (see reference numeral 14 in FIG. 3).

[0076] Under the adsorptive filter element 3, a flat intermediate filter layer 8, for example made of a nonwoven material, is provided in order to prevent the escape of adsorptive particles from the adsorptive filter element 3. The intermediate filter layer is made of a nonwoven material, which in particular has a higher air permeability than the filter medium of the particle filter element. The intermediate filter layer 8 is in particular a flat layer, in particular not folded.

[0077] The auxiliary frame 7 and the intermediate filter layer 8 further improve the stability and ease of handling of the indoor filter module 1. Furthermore, the filter module 1 becomes more resistant to accelerations such as vibrations, shaking and shocks.

[0078] The cubic-shaped unit of partial filter elements 2, 3, connected to one another by an auxiliary frame 7 and closed downwards by an intermediate filter layer 8, is laterally surrounded by a plastic frame 4 with radially projecting sealing stays or sealing flanges 5. In the figure, the axial direction A is indicated by a dashed line and the radial direction R by a broken line. When inserted in the housing, the sealing stays 5 are axially clamped between two corresponding housing parts 9, 10 by means of a seal 6 (see FIG. 5).

[0079] In the filter assembly 100 shown in Figures 4 and 5, the filter housing is formed from an upper housing part 9 and a lower housing part 10. The lower housing part 10 has a U-shaped receiving stay 11 protruding laterally outward for the seal 6 of the indoor filter module 1. The upper housing part 9 has a corresponding profile stay 12 which axially presses the seal 6 arranged around the sealing flange 5 against the receiving stay 11 to provide an airtight seal.

[0080] In this way, an untreated air region RO and a clean air region RE exist within the filter assembly 100. Air to be filtered, potentially containing dust and gas, enters the untreated air region RO from an inlet (not shown), passes through the two partial filter elements 2, 3 due to a pressure difference, and is collected in the clean air region RE as clean air for the vehicle cabin. The clean air in the clean air region RE is supplied to the vehicle cabin from an outlet (not shown).

[0081] The sealing flange 5 and the seal 6 as well as the housing parts 11, 12 have a rectangular shape. As shown in Figure 4, there is a sealing surface DE passing through the internal space of the housings 9, 10 and the internal volume of the cubic shaped adsorptive filter element 3. The sealing surface DE corresponds to the illustrated radial direction R in Figures 1 and 2.

[0082] The sealing surface DE in this embodiment passes through the centre of mass of the indoor filter module 1 in order to achieve a balanced mass ratio upon mounting of the indoor filter module 1 via the seal stays 5 / seals 6 in the housing parts 9, 10. More precisely, the sealing surface DE defined by the position of the sealing flanges 5 divides the total mass of the indoor filter module 1 into an upper half OM and a lower half UM. If the mass of the first part OM of the indoor air filter module 1 and the mass of the second part UM of the indoor filter module 1 are equal, the indoor filter module 1 is fixed in the housing 9, 10 in a stable manner, especially against accelerations.

[0083] If the mass proportion of the indoor air filter module 1 is unevenly distributed with respect to the sealing surface DE, the risk of tension due to accelerations is higher than in the proposed "equilibrium state". If the plane defined by the sealing flange is considered as the dividing surface (sealing surface DE), it can be said that the first part or upper half OM of the indoor air filter module 1 is approximately the same weight as the second part or lower half UM of the indoor air filter module 1. In this case, certain tolerances on the mass ratio are allowed.

[0084] In this embodiment, the sealing flange 5 surrounds the adsorption filter element 3 and is arranged opposite each side surface 14 of the moldings 3A-3E or the auxiliary frame 7 at the height of the honeycomb bodies 3A-3E of the adsorption filter element 3. Depending on the axial mass distribution of the composite of the partial filter elements 2, 3, it is also possible to arrange the sealing flange 5 at a biased axial height of the filter element composite.

[0085] Overall, the lateral outer mounting in the housing provides a reliable filter module with efficiently used filter media which is particularly robust against vibrations. [Explanation of symbols]

[0086] 1 Indoor Air Filter Module 2 Particle filter elements 2A Pre-filter layer 2B HEPA layer 3. Adsorption filter element 3A~3E Molded object 4 Frames 5 Seal flange 6 Seal 7 Auxiliary frame 8. Intermediate Filter Layer 9, 10 Housing parts 11 Seal housing 12A Headband 12B Sideband 13 Seal part 14 Circumferentially extending wall of the adsorption filter element 15 Filter media 100 Filter Assembly A axis direction DE seal surface R Radial direction L Flow direction LO Length direction OM upper mass UM bottom mass RE Clean side RO Untreated side

Claims

1. An indoor air filter module (1), comprising: A particle filter element (2), an adsorption filter element (3), and a frame (4) that circumferentially surrounds the particle filter element (2) and the adsorption filter element (3) and has a radially protruding seal flange (5), The particle filter element (2) comprises a folded pack formed of a plurality of layers of zigzag-folded filter media (15), at least one layer (2B) comprising an aerosol separation filter media; The particle filter element (2) comprises a first layer (2A) on the inlet side and a second layer (2B) on the outlet side, folded against each other to form the folded pack, The adsorption filter element (3) is configured as a honeycomb body and includes at least one molded body (3A to 3E) that adsorbs at least hydrocarbons, and the sealing flange (5) is arranged so as to laterally surround the adsorption filter element (3) at its circumferentially extending outer wall (14).

2. 2. The indoor air filter module according to claim 1, wherein the sealing flange (5) defines a sealing surface (DE), and the sealing flange (5) is arranged such that the sealing surface (DE) extends through the interior of the molding (3A-3E) configured as a honeycomb body.

3. 3. The indoor air filter module according to claim 1 or 2, wherein the sealing flange (5) defines a sealing surface (DE) dividing the indoor air filter module (1) into a first part (OM, UM) and a second part (OM, UM), and the sealing flange (5) is arranged such that the ratio of the mass of the first part (OM) of the indoor air filter module (1) to the mass of the second part (UM) of the indoor air filter module (1) is between 0.6 and 1.4, preferably between 0.8 and 1.

2.

4. 4. The indoor air filter module according to claim 1, further comprising an auxiliary frame (7) which surrounds the particle filter element (2) and the adsorption filter element (3) at least partially laterally and connects them to each other, the auxiliary frame (7) being connected to the frame (4), in particular glued to the frame (4).

5. The indoor air filter module according to any one of the preceding claims, further comprising an intermediate filter layer (8) arranged on the outlet side of the adsorptive filter element (3).

6. 6. The indoor air filter module according to claim 1, wherein the particle filter element (2) comprises a frame surrounding the folded pack, the frame including side bands (12B) provided on the pleats of the folded filter media (15) and a head band (12A) provided on the end pleats of the folded pack.

7. 7. The indoor air filter module according to claim 1, wherein one of the layers (2A, 2B) of the particle filter element (2) comprises an aerosol-separating particle filter medium (2A) of filter class H13 or H14 according to DIN EN 1822-1.

8. 8. An indoor air filter module according to any one of the preceding claims, wherein the adsorptive filter element (3) comprises a number of moulded bodies (3A-3E) connected to one another, in particular by means of a thermosetting potting compound.

9. 9. The indoor air filter module according to claim 1 , wherein the at least one shaped body (3A-3E) configured as a honeycomb body is at least partially made of a ceramic material, an activated carbon material, an ion exchanger material, a molecular sieve material, a zeolite material, an organometallic support material and / or a metallic material.

10. 10. The indoor air filter module according to claim 1, wherein the particle filter element (2), the adsorption filter element (3), the shaped body (3A-3E) configured as a honeycomb body and / or the indoor air filter module are each configured in a cubic shape.

11. Indoor air filter module according to any one of the preceding claims, further comprising a seal (6) attached to the sealing flange (5).

12. 12. The indoor air filter module according to claim 1, wherein the particle filter element (2) and the adsorption filter element (3) are arranged in the indoor air filter module (1) in fluid series, in particular the particle filter element (2) is arranged upstream of the adsorption filter element (3).

13. A filter assembly (100), comprising: A filter assembly comprising a filter housing (9, 10) accommodating at least one indoor air filter module (1) according to any one of claims 1 to 12, said filter housing having first and second sealing portions (11, 12) following the contour of said sealing flange (5) and / or seal (6).

14. 14. A filter assembly according to claim 13, wherein the sealing flange (5) and / or the seal (6) are axially compressed between two housing parts (9, 10) when the indoor air filter module (1) is positioned in the filter housing (9, 10) as intended.

15. The filter assembly according to claim 13 or 14, wherein the filter assembly (100) is designed for filtration according to category 4 according to DIN EN 15695-1.

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