Air filtration device with adsorption product and assembly method

Abstract

Disclosed is an air filtration device for purifying a target area to be ventilated, in particular for a vehicle passenger compartment, having a filtration assembly including granular product for capturing volatile compounds. This product is stored between two air-permeable walls, extending transversely with respect to a flow of untreated air to be filtered which enters the internal chamber lined with adsorption product through a holder (2) such as a frame. At least one of the permeable walls (5'), which is flexible, is connected by its outer surface to a reinforcing portion (4b) attached to the holder (2). This outer surface has base lines in the corrugated wall profile, and support by the reinforcing portion (4b) is provided at a plurality of support members, in the form of spaced-apart bars (7b, 7d), which are secured along fold lines including the base lines (LP1).

Description

AIR FILTRATION DEVICE WITH ADSORPTION PRODUCT AND ASSEMBLY METHOD Technical field

[0001] The invention relates to air filtration equipment in areas sheltered from external weather conditions, in particular passenger compartment air filtration systems, for example to enable the air in a passenger compartment of a vehicle, in particular a motor vehicle, to be purified during, before or after its operation. Technological background

[0002] In cabin air filtration applications, it is known to use filter elements to filter fluid flows or gaseous fluids, for example to filter an air flow that is supplied inside the cabin of a motor vehicle. The filter element is integrated into an air supply circuit from outside, with ventilation and / or air conditioning functions. In the automotive field, ventilation and temperature control equipment is commonly referred to as HVAC (Heating, Ventilation and Air-Conditioning). This system can be formed at the front of the vehicle and associated with controls accessible by the driver.

[0003] The increase in air pollution, especially in large cities, associated with the use of such air conditioning equipment in vehicles, causes a very significant deterioration in the quality of the air present / admitted into the vehicle's passenger compartment if the air is not purified and treated, by means of the filters of this HVAC equipment. For example, particle filters, odor filters or a combination of these are provided, which must filter or adsorb as best as possible suspended matter, particles and odors contained in the ambient air. Document US 2009 / 064862 shows an example of a monolithic multi-layer assembly filter incorporating an adsorbent such as activated carbon. The assembly incorporates a superposition of layers to achieve the separation of impurities and requires three manufacturing phases: first the formation of fine cuts in the respective layers each based on a flexible material, then obtaining a stack of the layers, and finally a longitudinal stretching carried out at the ends, making it possible to elongate the stack (compared to its unstretched shape) and to deform and convert the cuts into wider openings. The multi-layer structure is complex to obtain and the quantity of adsorbent material is relatively small, which leads to a rapid reduction in the duration of the purification efficiency.

[0004] Document WO2017 / 220691 describes an example of assembly for producing filters including pleated non-woven materials, for air filtration, by using a particular adsorption layer with integrated activated carbon, this layer being glued to the middle of a multi-layer structure, especially between two fibrous layers. The filter structure can be compact.

[0005] A disadvantage of filtration using a filter of the type described in WO2017 / 220691 is that the effective surface area available for adsorption remains limited. This limits the filter's effectiveness over time. Summary

[0006] In order to improve the situation, an air filtration device is proposed according to the invention, comprising: - a support having two ends distant from each other; - two air-permeable walls, substantially parallel to each other, each extending from one to the other of the two ends of the support; - a chamber, intended to contain an adsorption medium (such as activated carbon, for example), delimited between the two air-permeable walls, a first of the two air-permeable walls allowing a flow of raw air to be filtered to penetrate into the chamber, between the two ends of the support; in which a first wall among the two permeable walls, flexible and / or capable of being folded, is connected to at least one reinforcing part fixed to the support and connecting to the first wall selectively on a face of the first wall which is an outer face relative to the chamber, and in which the outer face has rectilinear bottom lines or zones in a corrugated profile of said first wall, the first wall being supported in a conformation with said corrugated profile by the reinforcing part which includes a plurality of support members secured to the first wall along the rectilinear bottom lines or zones.

[0007] The permeable walls can be spaced apart from each other within the integration compartment / space formed by the support. Such a filtration device allows for compact integration of the adsorption medium with the possibility of increasing the amount of product in the adsorption layer by dimensional adjustment of the spacing between the two walls. The total surface area for the passage of air into and / or out of the chamber can further be increased due to the corrugated profile on at least one of the (air-permeable) walls delimiting the chamber receiving the adsorption medium.

[0008] The support members may be directly or indirectly connected to the support, by a rigid fixing. These support members may include bars that are more rigid than the material of the first wall. The support members may be spaced and arranged parallel to each other. They may form bars (spaced and parallel to each other, preferably rigid) that may have at least two types of cross-section. The support members form all or part of a conformation-maintaining means connected to the support and making it possible to maintain and structure a corrugated profile conformation of the first wall, by a connection on the first wall which is discontinuous and distributed along rectilinear lines or zones of cusp in the corrugated profile of the first wall. Such a maintaining means has, for example, a peripheral portion for its attachment to a frame or similar support.

[0009] For one and / or the other of the permeable walls (upstream of the adsorption medium and downstream of this medium depending on the direction of air circulation), a bar structure, preferably in one piece, possibly molded from plastic material, can make it possible to bring together all the bars connected to the outer face of the permeable wall in question. Some of the bars can have a blade format to extend to the bottom lines of the outer face of the air-permeable wall. More generally, it is understood that the outer face of a first permeable wall is regularly connected to bars spaced and parallel to each other, forming at least the support members in the reinforcement part and making it possible to maintain and structure the corrugated profile conformation of this first wall. The bars do not pass through or bypass the permeable wall, these being adapted to be selectively / only connected to the outer face to achieve the bar-air-permeable wall connection. Typically, a bar side face serves for fixing against the permeable wall, preferably along a fold line made of a material constituting the first permeable wall. In other words, the bars are adapted to be selectively connected, each by a bar side face, to a face of the first wall which is an outer face relative to the chamber.

[0010] It is understood that the reinforcing part with the bars constitutes a means of maintaining conformation connected to the support which can avoid covering the permeable material (non-woven forming canvas or membrane) of the permeable wall considered, except for the fold zones, without cluttering the interior volume forming the chamber. Optionally, at least a portion of the bars may be connected to the bottom rectilinear lines or areas in the corrugated profile, while another portion of the bars may be connected to the ridge lines of the outer face in this same corrugated profile.

[0011] According to a feature, the two air-permeable walls can be adapted to extend transversely with respect to a flow of raw air to be filtered entering the chamber via one of these two walls, between the two ends of the support. The two permeable walls have four edges, which are for example inscribed in a virtual rectangle, these four edges each being linked to a flank constituting a part side of the frame or an inner frame portion configured to run along an outer frame of the filtration device intended to support the two reinforced permeable walls.

[0012] Thanks to these provisions, it is possible to adjust the depth (thickness) of the adsorption material layer according to needs, by adjusting the distance between the two permeable walls, while having a corrugated wall structured by bars that interfere with the air flow and can contribute to limiting the passage speed. In other words, the effective surface available for adsorption can be large and the passage time in the adsorption layer also increased. This makes it possible to optimize the filter efficiency and its durability.

[0013] Of course, the first permeable wall and possibly also the other wall called the second permeable wall may consist of fabrics or membranes having a pleated or undulating profile. This profile may result from a conformation with a succession of hollows / concavities as seen from the outside (opposite the chamber). In this way, the first permeable wall may locally widen the chamber towards an inlet face or an outlet face of the filtration device.

[0014] When the two walls are corrugated or pleated, the facing sides via the chamber can be parallel two by two. In this way, each V or U shape of a permeable membrane / wall can be in correspondence with the same shape (without mirror effect), so that the spacing provided to form the chamber can remain substantially constant. The spacings of the partitioning elements, in the direction of air circulation are then constant. As a result, the filling layer can have a homogeneous, substantially constant thickness, since the entire volume of the chamber is filled with product including / formed by the adsorption medium.

[0015] The support members, for example in the form of bars or elongated members following the direction of the folds / lines in the corrugated profile, are for example fixedly / rigidly attached to the wall, without relative mobility of the reinforcement part with respect to the support. The support members may form bars arranged transversely with respect to lateral, typically flat, flanks of the reinforcement part. A spar, parallel to the flanks and located in an intermediate position between the two flanks, may optionally be provided in the reinforcement part.

[0016] Optionally, the spar participating in the reinforcement extends in the direction of a pleating of the first permeable wall and generally follows the contour of the fold zones which it covers from the outside and of the inclined side panels / surfaces formed between two consecutive folds. In other words, the spar can extend in the folds, for example along an X axis parallel to a direction of extension common to both permeable walls defined by the front of the machine. The spar may comprise a plurality of reliefs projecting / returning towards the chamber 210. A flat portion of the spar may extend rectilinearly, forming a common base for the reliefs, which for example each have a triangular shape with a point oriented with a bottom fold line in the external face of the first permeable wall. This type of structure, with or without a stringer, can be used to reinforce each of the two permeable walls, depending on the option.

[0017] Advantageously, one of the permeable walls is supported from the outside (outside the chamber) which allows for an optimized volume for the adsorption medium. In options, there is a complete use of the space between the permeable walls, for example two canvases, the reinforcing means (with spacer effect of the folds) which supports the canvas or similar permeable wall (flexible or capable of folding) being on the outside. Each spacer / reinforcing means may consist of a piece of plastic material, forming bars having two types of depth following a direction of circulation of the air flow in the chamber. Each permeable wall can be made from a single piece, with a homogeneous, possibly constant, thickness which is typically submillimetric, for example ranging from 0.05 to a few millimeters.

[0018] Typically, the chamber for the absorption media may be limited by a frame and / or between two permeable walls, each having a corrugated profile and a spacer means provided with bars. It is understood that the filtration device has greater gas filtration efficiency without having too high a footprint in terms of filter thickness. Indeed, the corrugation of the permeable / filtering walls to delimit the chamber, makes it possible, in a given volume, to increase the air passage surface and thus reduce the pressure drop that can be induced by the increase in the mass of absorbent products, for example activated carbon. In embodiments, the device has one or more of the following features / arrangements: - at least one of the permeable walls has a corrugated profile with a submillimeter thickness. - a second wall among the two permeable walls is connected to bars which form a subgroup of support members entirely distinct from the support members connected to the first wall. - the support members consist of bars which preferably have the same length to define an identical length of fixing on the permeable wall to which they are attached. - in each bar structure, a spar (at least one spar) may be provided, parallel to two elongated sides of a peripheral frame, forming crossed junctions, typically at 90°, with an intermediate section (central section for example) of the respective bars which are distributed at regular intervals from one to the other of the two opposite ends / sides of the support provided in the form of a frame. - the first wall and the second wall, permeable to air, are kept spaced apart by a distance which may be directly proportional or substantially equal to a predetermined spacing. - the predetermined spacing is provided / defined within respective pairs of bars each including, on the one hand, a bar connected to a bottom line of the external face of one of the air-permeable walls, and on the other hand, a bar connected to a projecting line of the external face of the other permeable wall. - the two bars in such a pair can be located directly above each other for a generally horizontal arrangement of the two permeable walls. - the permeable walls have an identical undulating profile, so as to be superimposed with a stable / constant spacing, each of the bars fixed to one wall being arranged coplanar with another bar fixed to the other wall, thus forming a pair of bars. - between two adjacent pairs of coplanar bars, the air-permeable walls form two inclined sides parallel to each other whose dimensions are identical. - the two permeable walls are capable of forming, with the adsorption medium, a filtration stage to separate gases including volatile organic compounds. - the two permeable walls are parallel (generally parallel to each other) and distributed on either side of the same reference plane extending into the chamber. - the support members, preferably all in the form of bars, are divided into at least two groups with a differentiation in their height (or depth) as measured in a Z direction perpendicular to the reference plane. - the two permeable walls, made of flexible material and with a wavy profile, are each associated with a bar structure. - each bar structure, provided in / forming a reinforcement part directly in contact with the outer face of one of the permeable walls, is provided with parallel bars. - in each bar structure, a first type of bars is provided, for which each bar is attached and linked to a bottom line of the corresponding outer face, and a second type of bars, for which each bar is attached and linked to a projecting line of the corresponding outer face. - the bars of the first type can be wider / thicker than the bars of the second type, following a crossing direction perpendicular to the two walls air-permeable, for example so that the bars of the first type and the second type are flush at the same level. - all or part of the bars may possibly form deflector or air flow guide means, allowing a slowdown to increase the passage time of fluid in the chamber filled with adsorption media. - the adsorption media is stored in bulk between the two permeable walls. - the bulk adsorption media may further be stored within the circumferential boundary of a frame constituting all or part of the support. - a gap between the two permeable walls is greater than or equal to 5 mm. - the first wall is a pre-filter in relation to the adsorption layer filling the chamber, with for example an ability of the first permeable wall to separate particles of submillimetric diameter or characteristic size.

[0019] In embodiments, the support of the permeable walls extends peripherally around the chamber, for example with an annular format extending around a central axis. Optionally, the frame forming the support has a fixed or attached sealing portion for sealing a lateral access opening to the chamber. The sealing portion may extend peripherally, making it possible to close the annular shape of the frame. The access opening is the one that has made it possible to fill the chamber with adsorption media. Either the sealing corresponds to a weld, a glue or a similar permanent closure, or the sealing portion closes removably.

[0020] According to a feature, the two permeable walls each have an outer face at which a corresponding bar structure is fixed, preferably overmolded or welded, so as to obtain two preassembled elements. These elements are designed separately and can be held in a chamber-delimiting configuration with peripheral contact made against a common frame and / or using frame parts which join together with a position hold. Optionally, the frame is arranged to delimit a compartment in which are kept: - a first pre-assembled element which contains the first air-permeable wall; and - a second pre-assembled element which contains the other air-permeable wall.

[0021] The frame may include an internal face providing the attachment of the two pre-assembled elements. Optionally, the first pre-assembled element and the second pre-assembled element are mutually spaced by the frame, preferably by a portion of the frame including two elongated sides of this frame, so that the two bar structures are located only outside the chamber.

[0022] In embodiments, the filtration device has air deflection means integrated into the same compartment where the two permeable walls are housed, for example in a hollow interior space delimited by a frame forming all or part of the support. These deflection means may include all or part of the support members, for example by using a blade shape in bars constituting some of the support members. More generally, at least part of the support members may consist of partitioning bars of the passage section corresponding to the frame or support on which the air-permeable walls are mounted. Each of the partitioning bars having, for example: - two deflection faces oriented in opposite directions and extending parallel to each other from a first deflecting edge, preferably rectilinear, to a second edge, opposite the first deflecting edge, which defines a junction zone with a rectilinear cusp line or zone obtained by pleating as the bottom line of the first permeable wall (bottom line of the external face of the permeable wall), - an orientation of the two deflection faces opposite two adjacent portions of the first permeable wall, preferably rectangular, these two adjacent portions meeting at the junction zone.

[0023] In the filtration device, the two permeable walls and an adsorption layer including the adsorption medium make it possible to form a first filtration stage for separating gases. The device may further comprise a second filtration stage, for example in the form of a filter element carried by the support and / or attached to the support members which are connected, outside the chamber, to one of the permeable walls which has a corrugated profile. The second stage may make it possible to separate solid dust / fine particles. Optionally, the filter element is generally parallel to the first filtration stage or to the reference plane and adapted to separate solid particles and / or dust passing through the first filtration stage. The filter element is thus located downstream of the chamber in a direction of circulation going from one to the other of the two permeable walls.

[0024] The device's filtration stage, with activated carbon, with carbon used alone or combined with other materials in the chamber, allows it to retain not only certain particles but also sulfur oxides, exhaust gases and odors. This filtration stage can reduce the concentration of harmful gases inside the car, which can cause headaches and irritations. The design of the filtration stage can optionally consist of three filtration layers, two of which are reinforced from the outside: a layer based on activated carbon - the one that captures gases and odors - placed between two layers of so-called "non-woven" media, which retain large solid particles.

[0025] According to a particular feature, the filtration device may further comprise a second filtration stage, in the form of a filter element with non-woven media (possibly pleated media), this filter element being carried by the support and / or attached to the bars which are connected, outside the chamber for the adsorption media, to one of the permeable walls (which preferably has a corrugated profile). The filter element may be parallel / generally extend parallel to the reference plane provided in the chamber, possibly being adapted to separate solid particles and / or dust passing through the first filtration stage.

[0026] In embodiments of the device it may be provided to integrate one or more of the following provisions: - the adsorption medium is granular activated carbon, possibly suitable for recycling (for reuse), for example via a thermal reactivation type process. - the size of the adsorption media grains is between approximately 0.1 or 0.2 mm and 2 or 3 mm.

[0027] According to one aspect, there is provided an air filtration arrangement for a vehicle cabin, comprising: - a receptacle, for example in the form of a duct or a housing, provided with an inlet for raw air and an outlet for purified air; and - the filtration device as mentioned above, mounted internally in the receptacle, so as to separate an upstream zone of the filtration in communication with the inlet, and a downstream zone in communication with the outlet; in which the adsorption medium is stored in bulk in the chamber delimited between the two permeable walls, forming a layer of thickness at least equal to 5 mm.

[0028] Typically, the circumference of the chamber is delimited by a frame which delimits an access opening following a plane, on the side of the upstream zone, the frame supporting: - two air-permeable walls provided in the filtration device, by means of two respective bar structures, including the one connected to said first wall, the two bar structures extending parallel to the plane of the opening of the frame while being kept spaced from each other by the frame; and - an annular seal or a sealing lip for annular contact on a complementary inner face located in the receptacle and participating in separating the upstream zone from the downstream zone.

[0029] With an integrated arrangement of the bar structures, which are entirely contained within a compartment defined by the frame, the filtration device is compact to allow minimizing certain dimensions of the receptacle. The chamber filled with adsorption product / media can have an average depth less than the depth of the frame and greater than or equal to one-third of the depth of the frame.

[0030] The arrangement may belong to a system for purifying the air in a passenger and / or driver's cabin, in particular in a motor vehicle cabin, the system comprising: - an air purifying filter medium separating at least the classes of fine particles PM0.3 and PM0.1, said filter medium preferably being of class H13, and at least one layer for the capture of volatile compounds, in particular by molecular adsorption. - a filtration chamber in which the permeable walls extend so that the filtering arrangement delimits an upstream zone in communication with one or more intake channels of the system, to bring in a flow of fresh outside air; - a means of circulating air; - optionally a pre-filter to capture solid and / or liquid particles upstream of the filtration chamber (according to a direction of air circulation which can be selectively permitted by the air circulation means).

[0031] In embodiments, the support is common to two filtration stages: a first filtration stage for separating / adsorbing gases, consisting of the multilayer structure including the two preassembled elements (each with their permeable wall or membrane) and the adsorption media layer interposed between these two elements. End bars of complementary depth and joined by their distal edge to the permeable walls may be provided in the two bar structures, for example on two short sides of the device, parallel to the general direction of extension of the fold lines.

[0032] Two elongated, rigid flanges may be provided to border the long sides of each of the fabrics or similar non-woven elements forming an air-permeable wall. In options, the spar is an intermediate element of identical structure to the two flanges and can be placed midway between these two elongated and parallel flanges.

[0033] According to a particular feature, the air purifying media is part of a filter element: held between two sides of the frame surrounding the two flanks of the reinforcing part; and / or which is placed against the other of the two permeable walls. This filter element forms a second filtration stage and is suitable for separating solid particles and / or dust passing through the first filtration stage (i.e. downstream of the chamber).

[0034] The arrangement allows to advantageously combine the advantages of mechanical filtration (filtration size) and the adsorption capacity of volatile / odorous compounds.

[0035] The presence of a HEPA type filter element (for high efficiency airborne particle filtration), which has a suitable filter media, for example with at least one integrated ePTFE membrane layer, to meet the criteria of filter class H13, offers an advantage in avoiding (re)circulating unwanted fine particles into the passenger compartment.

[0036] In embodiments utilizing a frame, one or more of these arrangements may optionally be employed for the filtration device: - the opening of the frame is adapted to open internally into the chamber, between the two air-permeable walls (walls capable, for example, of retaining the grains / solid particles of the adsorption medium). - the frame can be rectangular or polygonal. - the support may have a shape with roundings or curves. - two elongated flanges cover / overlap the ends of the fold lines, these fold lines may be shorter than the two flanges.

[0037] In a parallelepiped format option, the filtration device can: - constitute a cassette filter, for example sliding linearly into a housing of the receptacle, with a removable attachment in this receptacle; - and / or include a layer of adsorption media with an air-purifying effect delimited by two permeable walls whose thickness is substantially identical, the adsorption layer preferably having a substantially constant thickness. - fully integrate the undulations of one and / or the other of the permeable walls into the thickness of a frame, the layer extending in an essentially flat manner between the two ends of its support which constitutes a frame.

[0038] The layer may correspond to an activated carbon-based layer for capturing volatile compounds. At least one additional filtration medium, possibly of the HEPA type, may be arranged upstream or downstream of this layer, preferably extending into the same filtration chamber delimited by a receptacle or a ventilation duct (HVAC type for example).

[0039] In some embodiments, the permeable walls may have a generally tubular or half-tube conformation while having a corrugated profile, at least for the first wall. In this case, the support may consist of a elongated support along the longitudinal direction of the tubular shape and opposite parts or flanges axially covering the chamber delimited between the permeable walls.

[0040] In a tubular or curved / arched format option, the air-purifying adsorption media layer may extend annularly (partially annularly) around a central axis and is designed to allow air filtration, for example towards a center of curvature or centripetal type, forming a layer for the capture of volatile compounds. Two flanges covering the ends of the fold lines may be provided. A possible filtration media, possibly of the HEPA type, may be arranged internally or externally with respect to this layer, extending around a hollow space, the hollow space preferably forming part of the downstream area of ​​the filtration chamber delimited in a receptacle where the filtration device is housed.

[0041] In embodiment options, one or more of the following features are provided for the filter medium of the second filtration stage: - the filter medium is parallelepipedal and / or is configured to separate particles of submillimetric diameter or characteristic size, for example of size less than or equal to 0.1 or 0.2 mm. - the filter medium has a circumference corresponding to a perimeter substantially identical to a perimeter of the first filtration stage, defined by the different sides of the first air-permeable wall.

[0042] Optionally, the second-stage filter media is or is part of a HEPA H13 or higher filtration grade filter. The filter media can be of the rectangular pleated type.

[0043] In the options for producing air-permeable flexible walls, a wide variety of permeable structures, perforation and / or pore sizes can be used, preferably with homogeneity in the distribution of mesh sizes or microperforations, so that pressure drop effects are identical or similar over the entire surface of these walls.

[0044] According to another aspect, there is provided a method of assembling an air filtration device as above-mentioned, the method comprising the steps essentially of: - assembling, during an assembly step, a first air-permeable wall and a first bar structure, so as to maintain or structure a pleated or wavy conformation of the first permeable wall, which may be flexible, whereby a first pre-assembled element is obtained; - provide a second air-permeable wall, which can be flexible; - surrounding the first pre-assembled element and the second permeable wall by a frame forming a support having two sides or ends distant from each other, during a step of placing the frame, so as to produce a fixing which keeps the second permeable wall oriented parallel (therefore parallel) to the first permeable wall, parallel to an opening of the frame and extending from one to the other of the two ends of the support, whereby a chamber delimited between the first permeable wall and the second permeable wall and surrounded by the frame is obtained; - after the step of placing the frame, filling the chamber with an adsorption medium, for example via an opening in the frame, to form a layer made of or based on said adsorption medium which extends transversely with respect to a flow of raw air to be filtered entering the chamber through / via one of these two walls, between the two ends of the support; knowing that thanks to the assembly step, the first wall is connected to bars of said structure which form support members spaced apart and parallel to each other, in order to support and structure the pleated or undulating conformation of the first wall, by making a connection of the bars on the first wall by a lateral face of bar respectively for each of these bars, against the same face of the first wall, in a discontinuous manner and distributed along rectilinear lines or zones of cusp in an undulating profile of the first wall.

[0045] With this type of assembly, it is possible to obtain an air-permeable wall, for example in the form of a canvas or membrane, which is delimited by a perimeter reduced in length compared to a length of this wall in a deployed state, while allowing the adsorption media to form a significant layer in the chamber directly delimited by this (typically flexible) wall with a corrugated profile.

[0046] The step of setting up the frame is carried out in such a way that the face of the first wall, on which the bars are connected, is an external face with respect to the chamber (selective connection of the bars to this external face). In this way, none of these bars are in the chamber and the adsorption layer can be in contact with the majority of the internal surface of the permeable wall, optimizing the active surface available in the chamber. Rectilinear lines or areas at the bottom of the external face are part of the cusp zones (in the corrugated profile) on which the reinforcement / support part is connected, via the bars.

[0047] Additionally, the bars of the bar structure may include bars, external to the chamber, having a comparatively reduced depth dimension compared to other bars of greater depth, so that the first permeable wall is linked to the bar structure in base lines (by the more extended bars following a direction perpendicular to the walls) and in ridge / projecting lines (by the other comparatively thinner and / or less deep bars) of its external face.

[0048] The filling step is followed by a closure to seal the opening that allowed the filling, this opening being arranged laterally in the frame. The closure part used for this closure can be mounted removable so as to make the filtration device rechargeable, for example rechargeable by a single opening of the frame / support from the side. More generally, the filter is rechargeable and / or provided with an adsorption medium that can be purged or rinsed, if necessary with the possibility of total or partial recharging using a frame opening, which is possibly the opening for the initial filling.

[0049] According to a particular feature, the spacing between two salient lines corresponding to two successive crest folds (at least in the pleated or undulated profile of the first air-permeable wall) is greater than or equal to a portion width defined in the first permeable wall between one of these two crest folds and a bottom line corresponding to a bottom fold interposed between the two crest folds considered. Additionally or alternatively, a bar of the bar structure has a connecting edge with the bottom line of the first permeable wall extending, in a direction away from the chamber (direction which is perpendicular to the first wall), to another opposite edge projecting outwards, which is preferably projecting at least at the same level as the crest folds or at least the two crest folds adjacent to / closest to the bottom line in question in the same (first) permeable wall. This arrangement can be applied to the second air-permeable wall, also associated with a reinforcing part whose structure is bar-like.

[0050] A fabric and the bar structure can be overmolded, for example at the same time or immediately after the fabric has been shaped with a corrugated profile. The result is a pre-assembled element with a reinforcing and protective effect to maintain the corrugated conformation of the air-permeable layer / wall. Permeable walls can be fibrous, for example based on synthetic fibers and / or polyester.

[0051] When the support is annular or frame-shaped, the spacing direction between the bars may be parallel to an extension axis of the support from one to the other of two axial ends, one of which may be opened during a step of filling with adsorption media. The support is for example elongated along this extension axis, optionally being at least two or three times as long as it is wide. It can also be at least two or three times as wide as it is deep. Brief description of the drawings

[0052] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Figure 1 is a perspective view of an air filter according to one embodiment of the invention, illustrating the zig-zag profile of a first permeable wall secured to a first support structure and making it possible to retain an adsorption product. Figure 2 is a sectional view of the air filter of Figure 1 having a two-wall permeable arrangement having the zigzag profile. Figure 3A is a perspective view of two respective pre-assembled elements and an associated frame, before an assembly phase, making it possible to illustrate a second permeable wall making it possible to retain the adsorption product as well as an associated reinforcement part. Figure 3B is a perspective view of a reinforcing portion that may be associated with either of the corrugated profile permeable walls / sheets. Figure 4 illustrates a detail of a multi-layer filtration arrangement, at least one of which is used to filter dust and / or provide H13 level filtration. Figure 5 is a schematic view of an example of integration of a filtration device in a housing. Description of embodiments

[0053] With reference to Figures 1, 2 and 5, there is illustrated a filtration device 1 intended for the purification of a flow of raw air F (possibly pre-filtered) coming from the outside and intended to be transmitted into a target location such as a vehicle interior, a room of a premises or the like. The device 1 may be part of an air conditioning system. A support such as a frame 2, provided in the device 1, may constitute a peripheral part which extends around at least two layers. A material 3 for filtration and / or retention of solid particles may be visible on the side of an openwork inlet face of the filtration device 1, here with multiple openings 04 formed within a wide opening delimited by the frame 2.

[0054] The frame 2 may be elongated and provided with two ends E1, E2 which may optionally define a width of the filtration device 1. The wide, axially opposite openings of the frame 2 may be of comparable or identical dimensions, delimited by the frame 2 which extends annularly around a central axis A. At least one bar structure, serving as a reinforcing part 4a, is coupled to the fabric or flexible retaining element / wall 5 which extends across the frame 2. The wall 5 makes it possible to cover (from the inside of the frame) the passages or openings 04 formed by the reinforcing portion 4a and is kept spaced apart to form at least one compartment for adsorption media M. For example, as in the non-limiting case of Figures 4 and 5, a single chamber is formed, corresponding to an interior volume V delimited between two thin retaining elements corresponding to the wall 5 and another wall 5' facing each other. The wall 5' forming the outlet side for the air passing through the layer of adsorption media M via the openings 04.

[0055] With reference to Figure 2 and Figure 4 in particular, the reinforcement can be carried out from the outside, outside the chamber V. For example, the incoming pressure on the flexible wall 5 deforms the canvas or similar flexible material (non-woven or other) constituting this wall 5 very little, due to the junctions J5 between the external face F5 and the reinforcing part 4a whose position remains fixed relative to the support / frame 2. The reinforcing part used can be formed in a single piece, for example molded from a block of plastic material. In one option, as visible in Figure 2, an annular seal 6, for example made of compressible plastic, elastomer or suitable material, can be sandwiched laterally between the rigid frame 2 and sides or flanges 41, 42 formed laterally on two reinforcing parts 4a, 4b associated / coupled with the walls 5, 5'.More generally, it is possible to create an annular seal around the edges of the walls 5, 5', against an inner face of the frame 2 or similar support.

[0056] Regardless of the specifically chosen use, the air filtration device 1 may have an adsorption layer structure delimited between two air-permeable fabrics, membranes or elements covering this layer and adapted for retaining the granular or loose adsorption material M provided in this adsorption layer. The adsorption material M includes, for example, activated carbon. The two retaining elements are referred to hereinafter as air-permeable walls or permeable walls 5, 5', which define an air passage surface in the filtration device 1. The frame 2 may surround these two permeable walls 5, 5' and constitutes an open / through frame (typically without a part covering the useful surface of the air-permeable walls 5, 5').

[0057] As clearly visible in Figures 1 and 3A, the frame 2 or support makes it possible to delimit a section of air passage open at two opposite ends, without allowing the air to escape laterally relative to the direction of the central axis A, which may correspond to the direction of air flow. The geometric shape presented here for the frame 2 is rectangular but this is in no way limiting. A support shape having a direction of extension along an axis of elongation may be preferred, with for example the presence of two end pieces 2a and two straight, parallel edges or sides 2b, which may cover edges of the permeable walls 5, 5', at least one of which is corrugated. These two sides 2b extend from one to the other of the end pieces 2a which are parallel to each other and parallel to the folds provided in the wall(s) 5, 5'. Obtaining a reinforced air-permeable element

[0058] Before starting the assembly of the filtration device 1 using the support / frame, the walls 5, 5' are prepared and supplied in a suitable format. It is typically provided to provide a canvas or similar textile / medium material permeable to air, possibly using a continuous roll or similar. This material may constitute the permeable wall 5 and possibly the other permeable wall 5'. A cut may possibly be made to obtain the desired width, in a splitting station. Folds are then formed, for pleating or obtaining a corrugation: a corrugated profile may thus already be obtained. The material may possibly be preheated in a heating station (infrared or other means) to facilitate the processing to obtain this corrugated profile.

[0059] In the non-limiting examples illustrated, the two permeable walls 5, 5', optionally with rectangular circumference, have a wavy profile with fold lines LP1, LP2, so that these walls 5, 5' form reliefs / peaks, for example regularly spaced at the level of their protruding crests / fold lines LP2.

[0060] To reinforce the walls 5, 5', a weld or overmolding can be carried out to attach the reinforcing and holding part 4a or 4b constituted by the bar structure. With reference to figures 1 and 5, at least one flexible wall among the two permeable walls 5, 5' is kept folded / corrugated by being attached to a corresponding reinforcing part 4a or 4b mounted internally in the support. With this attachment, it is easier to mount the two permeable walls 5, 5' on a support such as a frame 2. The walls 5, 5' can extend transversely with respect to a flow of raw air F to be filtered entering the chamber V via one of these two walls 5, between the two ends E1, E2 of the support / frame 2.

[0061] During the bonding step, continuous contact against the structure forming the reinforcing part 4a or 4b, on two undulating edges of the flexible wall. This contact resulting from the fixing can optionally be obtained at the level of the flanges 41, 42 of the reinforcing part 4a, 4b. These flanges 41, 42 which can be toothed (with the same orientation, towards the inside, of the triangular-shaped teeth) and possibly at the level of a contact zone with a spar 17a, 17b also toothed. There can be a correspondence of undulating shape / profile between the rigid toothed structure provided in the reinforcing part 4a or 4b and the undulating profile of the corresponding permeable wall 5, 5'. This type of arrangement is clearly visible for example in Figures 3A or 3B. When a spar 17a, 17b (at least one spar) is provided in the structure to bars, parallel to the elongated flanks 41, 42, such a spar 17a, 17b can form crossed junctions, typically at 90°, with an intermediate section (central section for example) of the respective bars which are distributed at regular intervals from one to the other of the two opposite ends / sides of the structure / reinforcing part 4a, 4b considered.

[0062] In addition or as an alternative, the reinforcing part 4a, 4b has elongated support members parallel to the general direction of the folds of the reinforced wall 5, 5', which are connected directly to the outer face F5, F5' (relative to the internal chamber V) of this flexible and permeable wall. This part 4a or 4b can thus be selectively connected to this outer face F5 or F5' at the level of lines LP1 or rectilinear bottom zones in the corrugated profile of the permeable wall 5 or 5'. The support effect can be obtained by carrying out these fixings of the reinforcing part 4a, 4b on all of the fold lines LP1, LP2, namely the bottom lines LP1 and the crest lines LP2 of the pleated / corrugated outer face F5, F5'.

[0063] The fixing can be done by maintaining the structure 4a or 4b sandwiched between two pressure or containment elements, for example with pressure elements distributed on the outside of this welded or overmolded assembly. The connections (structure 4a or 4b - external face F5 or F5'), distributed discontinuously, can be obtained simultaneously in the form of several strips (for example each continuous) oriented in a direction parallel to those of the pleating lines LP1, LP2 which form fold or cusp lines: respectively hollows and peaks in the corrugated profile. In the case illustrated in Figure 4, it can be seen that the pleating has been carried out in a similar or identical manner for the two permeable walls 5, 5'. In addition, the connection with the reinforcing part 4a, 4b can make it possible to obtain a pair of identical preassembled elements or with identical geometry for the air-permeable part 5, 5' of these elements.

[0064] In assembly options, each bar structure extends along the XY plane as seen in Figure 2 in particular, including an interior frame part or suitable peripheral portion, so as to present: - two flanges 41, 42 for lateral support of the corrugated edges of the walls 5, 5'; - two termination ends (which are two complementary opposite sides of the two flanges 41, 42) parallel to the folds and supporting the other edges, typically straight, of the walls 5, 5'. The two flanges 41, 42 here form two interior faces F2 facing each other, in a rectangular structure for example (possibly with the presence of a beveled angle in a variant).

[0065] In options, the reinforcing portion 4a, 4b may optionally be bonded to the support / frame 2 using a variety of techniques, such as overmolding / bonding or thermal welding, adhesive bonding or ultrasonic bonding. In embodiments, the station for welding / bonding may be located downstream of a rotary pleating device, with use of a guide ensuring the desired spacing between the lines on which the bars 7a, 7b, 7c, 7d or similar support members are laterally fixed. At least one bar 7a, 7b of the reinforcement structure / part 4a, 4b may have a joining edge welding / adhering to said bottom line LP1 in a rectilinear joining zone J5, as illustrated in particular in FIG. 4. The bar 7a, 7b provided with this edge may extend, in a direction away from the chamber V which is perpendicular to the reinforced wall, to another opposite edge projecting outwards, which is preferably projecting at least at the same level as the two crest folds LP2.

[0066] In one embodiment, the pleating of a fabric / wall 5, 5' can be carried out at the same time as a fixing, for example by welding or overmolding, between the fabric forming the permeable wall 5, 5' and the bars 7a, 7b, 7c, 7d of the reinforcing part 4a, 4b. This fixing is done at the fold lines LP1, LP2 of the fabric and also on the two elongated edges shaped in a zig-zag, by using two elongated flanges 41, 42 included in the reinforcing part 4a, 4b, as visible for example in Figures 3A and 3B. In certain options, a pinch can be provided for holding the wavy elongated edges. By sealing these wavy edges and the transverse straight edges to a continuous peripheral portion of the reinforcing part 4a, 4B, optionally using a hardening and / or physically setting resin or adhesive, the adsorption medium M can be effectively and simply prevented from flowing out at the edges.

[0067] With the reinforcing part 4a, 4b fixed on the corresponding permeable wall 5, 5', it is possible to fix / rigidify the plurality of folds defining, in each permeable wall 5, 5': - the plurality of protruding edges or fold peaks (LP1 fold lines); - the plurality of bottom lines (LP2). These fold lines LP1, LP2 delimit between them the inclined surface sections extending towards the interior of the chamber V from the protruding edges / protruding lines LP2 which are perpendicular to the pleating direction (direction of the pleating operation in the pleating device).

[0068] The juxtaposition of two elements thus pre-assembled makes it possible to form / delimit the chamber V. We obtain an adsorption unit including the parts of reinforcement / support 4a, 4b and delimiting the chamber V, which consists of the two pre-assembled elements, for example juxtaposed using a frame part. Each canvas forming a membrane 5, 5' may have the same elementary pattern 15 which is repeated. Such a pattern 15 may have a "V" shape in profile view, as shown for example in Figure 4. For example, an angle a5 of between 95 and 160° is obtained internally at the fold line LP2, this angle a5 being measured between the adjoining / meeting sides (planes) at this line LP2 on the interior / chamber side.

[0069] With reference to figures 2, 3A, 3B and 4, an example of a bar structure 7a, 7b, 7c, 7d is shown which can be used to maintain the undulating profile of a permeable wall 5 or 5'. The bars 7a, 7b, 7c, 7d extend parallel to each other in the manner of purlins of a roof frame, with a triangular arrangement in profile view for the three free edges of three successive bars. This can be made possible by a blade structure of some of the bars 7a, 7b bearing on the fold lines LP1, which are alternated with other bars 7c, 7d which are less deep in the direction of circulation of the air flow (direction Z recalled in figure 2) and thus less protruding in the direction of the chamber V.

[0070] This type of structure, which is not limiting, can be made for supporting and maintaining the conformation of the two permeable walls 5, 5', which can be identical or similar. A reinforcing part 4a can form the inlet face of a filtration stage by using the adsorption medium (activated carbon or similar for molecular adsorption), with the openings 04 delimited between bars 7a, 7b, while another reinforcing part 4b can form the outlet phase of this filtration stage, with the openings 04' (visible in FIG. 3A) delimited between the bars 7c, 7d. Optionally, activated carbon can be deposited / supported on an air-permeable substrate. It is understood that the adsorption medium M is held between the two walls 5, 5' and surrounded by a lateral / peripheral structure without opening during operation of the device 1.

[0071] Options for obtaining a reinforced element for delimiting an internal face in contact with the adsorption medium have been set out above, by using a single canvas or flexible wall whose external face is directly fixed to a reinforcement part 4a or 4b. Two pre-assembled reinforced elements can thus be obtained. Of course, it is also possible to provide only one reinforced element of this type, for example to form the interface through which the raw air flow F enters the adsorption layer. On the rear / downstream side of this adsorption layer, it is possible to use another type of reinforcement, for example with a more conventional grid and / or the use of locally stiffened portions (at the level of folds for example) on the other permeable wall 5'. Non-limiting examples of geometric / dimensional parameters

[0072] In the device illustrated in Figure 1, the number of fold lines LP1, LP2 is greater than ten, for example greater than or equal to fifteen, which can apply to at least one of the walls 5, 5'. The angle formed by each fold and the distance between two folds (forming a width of the sides) can be chosen so that an air-permeable corrugated wall 5, 5' has a height (which can correspond substantially to the height L7 of a blade-shaped bar) less than 9 mm, for example less than or equal to 5 or 6 mm.

[0073] For a spacing between permeable walls of between 5 and 15 mm, the total extension in height of the adsorption part can be between 15 mm and 33 mm. In Figure 5, a compartment area C1 corresponding to such a height of the adsorption part is illustrated. When an additional filter element 8 is provided to form a second filtration stage, the height H of the device 1 with two filtration stages can be approximately twice the height of the adsorption part, possibly without exceeding a threshold height of 60 or 70 mm.

[0074] With reference to Figures 1 and 5, the media of the element 8 is pleated, shaped in a parallelepiped manner, between two faces 8a, 8b, with a thickness similar or equal to that of the adsorption stage. The filtering media 8 can extend inside a housing or receptacle 30 by being inserted in a single block with the adsorption part. A thin cassette is thus formed (in Figure 5, the thickness dimension is exaggerated for the purposes of illustration). Here, an arrangement 10 is formed, capable of separating an upstream zone Z1 from a downstream zone Z2 in the filtration chamber delimited by the housing / receptacle 30. The air to be purified F, coming from the outside, is conveyed into the chamber via an inlet 1a of the housing 30 communicating with the upstream zone Z1. The inlet may open into the housing 30 opposite an inlet face formed by the reinforcing portion 4a, which is locked in position by the frame 2 or by an annular fastener for connection to the frame 2.An elongated shape may be preferred, for example with end pieces 2a twice or three times shorter than a length L5 of the reinforced elements 4a, 5 and 4b, 5'. To allow the height offset (along the Z direction) of the fold lines LP1, LP2, the bars 7a, 7b have a height L7 much higher than the height L7' of the bars 7c, 7d, for example with an excess / differential height of at least 3 or 4 mm. Example(s) of composition of multilayer structures with adsorption media

[0075] The permeable walls 5, 5', preferably flexible, may include or consist of a polyester fabric. Regardless of the choice of the material of the permeable wall 5, 5' to delimit the interior chamber / volume V, a common mesh size or similar (preferably identical) may be chosen. By way of non-limiting example, each permeable wall 5, 5' may have mesh sizes between 200 and 340 pm, for example ranging from 210 or 250 to 300 pm.

[0076] The reinforcing part(s) 4a, 4b may consist of a molded part, made of a plastic material that is more rigid than the material constituting the walls 5, 5' with a corrugated profile. Apart from elongated flanges 41, 42 (on two sides) and one or more optional longitudinal members 17a that may define a thin corrugated surface, locally matching the outer face F5 or F5', the structure of these parts 4a, 4B consists essentially of parallel bars 7a, 7b, 7c, 7d that are compatible with plastic welding and / or overmolding. The walls 5, 5' may also include or consist of a plastic material, for example at least one polyester or synthetic fibers. The reinforced element(s) may be devoid of a metallic component.

[0077] The adsorption media M, in bulk, can have a powder / granular consistency. As seen in particular in Figures 4 and 5 showing a filled state of the chamber V, the activated carbon or adsorbent media is typically in bulk / granular state, with a chamber spacing / thickness that can reach or exceed 5 or 8 mm. A thickness of 14 mm may be suitable to accommodate a high ventilation / air renewal flow rate.

[0078] The adsorption medium M may be granular and have a porosity allowing a physisorption effect (type of adsorption of gases when these are lodged in pores of the adsorption medium). Activated carbon may be contained in the filling material, in the chamber V. The retention of the adsorption medium M does not require fixing, gluing or the like against the walls 5, 5' or against any peripheral delimiting wall (such as the flanges 41, 42 or the transverse blades which join the ends of the flanges 41, 42). By using a cloth or a fibrous / textile material with sufficiently fine meshes (for example from 210 to 300 μm), the adsorption medium M may be retained in the chamber V.

[0079] In the walls 5, 5' and / or in a filter medium of the element 8, an agent with an antimicrobial and / or anti-allergenic effect may be provided. The rigid frame 2 may support the filter element 8 solely mechanically, by pinching for example, or may include an adhesive fixing component. Optionally, the filter element 8 may be fixed interchangeably.

[0080] The media of the filter element 8, possibly provided with pleats, may be multi-layered. It may be fibrous, based on cotton, cellulose, synthetic fibers for example or a mixture of fibers. In embodiments, at least one of the filtering medium of this element 8 and the fabrics constituting the walls 5, 5' is of the type subjected to a heat treatment, to maintain a pleating due to a hardening effect. In options, a layer of microfibers (e.g., ultrafine microfibers) in the filter element 8 is capable of separating more than 98% of fine dust and soot particles that may be suspended in the outside air. The filter element 8 may also have a specific antimicrobial layer that acts against viruses and bacteria, e.g., of level H13 or better, and which optionally prevents the growth of mold and fixes allergens and pollen in the filter layer. Assembly of the filtration device

[0081] The reinforcing parts 4a, 4b each have a peripheral portion called in the following the inner frame part. The two frame parts can form, by superposition, an annular insertion portion having a polygonal section, inserted through a large opening delimited by the frame 2, until it abuts the shoulder 2e, internal edge or similar reliefs. Optionally, the deformable seal 6 visible in Figure 2 can first be attached / put in place around the two frame parts, then the insertion of the annular portion is carried out, so as to allow the seal 6 to be sandwiched, for example with a compression effect caused by the frame 2.

[0082] The frame 2 thus delimits an adsorption filtration compartment C1. At least one of the two frame parts may include a slot or opening for filling with adsorption media M, which is carried out at a later stage. In one option, these two parts are inner frame parts that complement each other to obtain a polygonal circumference corresponding to the geometry of the frame and that are mounted in the outer frame 2. In this case, it may be provided first to superimpose the two inner frame parts, forming an opening on one side for access to the inner chamber / volume V delimited between the permeable walls 5, 5'.

[0083] Alternatively, the frame 2 may be assembled by assembly, for example by fixing several external frame parts around the juxtaposed pre-assembled elements with a gap permitted by the spacer elements T1, T2 included at the periphery with the reinforcing parts 4a, 4b.

[0084] In the non-limiting case of figures 3A and 3B, the two flanges 41, 42 can have several types of spacing elements oriented inwardly when mounted in the frame 2: - first spacer elements T1 formed on a top of the teeth of one of the flanges 41 or 42, thus being laterally offset on one side by the walls 5, 5' ; and - second bracing elements T2, for example constituting end bars T2 in the form of a blade in the reinforcement part 4a or 4b, which are positioned along the end pieces 2a of the frame 2, having a width equal to that of the walls 5, 5'. Such spacer elements serve to keep the walls 5, 5' at a constant distance from each other, with a sufficient spacing to allow the capacity of the chamber V to be increased, while preventing the structure of the parts 4a, 4b from extending into the chamber. The re-entrant teeth are only provided on one side, with the possible exception of the teeth of the spar 17a, which is thin, for example having a width less than or equal to 2 mm.

[0085] The illustrated options are given by way of example and, in the general method of assembly, it is provided at least to assemble a flexible wall / canvas 5 or 5' to a reinforcing part 4a, 4b, so as to maintain a pleated or corrugated conformation of this permeable wall, whereby a first pre-assembled element. With the other air-permeable wall, the chamber V can be delimited by surrounding the first pre-assembled element and the second permeable wall by a frame or similar support, during a step of placing the frame 2, so as to achieve a fixation which locks the relative position of the walls 5, 5' between them, independently of the presence or not of a reinforcing structure designed separately for the other permeable wall.

[0086] The walls 5, 5' are then maintained in parallel and access remains free, laterally, for filling the chamber V thus created. One side of the frame 2 is open in the cassette obtained before loading with adsorption medium M. This open side allows filling with carbon or similar adsorption medium. It is closed after filling, for example by a fixed or attached shutter 24.

[0087] In embodiments and as illustrated for example in Figure 3A, the spacing e4 between two salient lines LP2 corresponding to two successive crest folds can be greater than or equal to a portion width L (width of the flat-shaped panel) defined in the wall considered 5 or 5'. Such a panel, typically rectangular, is delimited between one of these two crest folds LP2 and a bottom line which is that of the fold inserted between the two crest folds.

[0088] In practice, during normal operation of the filtration device 1, the air admitted into the upstream zone Z1 is oriented onto an openwork face of the first reinforced element, onto the inlet face / external surface F5 of the wall 5 with a corrugated profile and can only reach the downstream zone Z2 by passing through the outlet face defining the external surface F5' of the wall 5'. The sides are inclined with two alternating orientations relative to the plane P of the access face of the frame 2, so that the flow F is deflected (in part) by the bars 7a, 7c and guided obliquely through the permeable wall 5, before reaching the interaction surface of the adsorption material M in the chamber V.

[0089] The frame 2 may carry, via a groove G for example, an annular seal J or a sealing lip for annular contact on a complementary inner face located in the receptacle 30 and participating in separating the upstream zone Z1 from the downstream zone Z2. As in the non-limiting case of FIG. 2, the seal J which extends for example along the XY plane may include two thinned lips or contact portions PC1, PC2, which may rest on an inner rim of the receptacle 30. The fixing region RF may be offset inwards, substantially at the same level (along the direction of the Z axis) as the fixing zone of this seal J on the frame 2. An inner annular skirt of the frame, offset inwards relative to a lower edge of the frame 2 where the seal J is secured, may be interposed between the seal J and the top of the filter element 8. Use of an additional filter element

[0090] As visible in Figures 1 and 2, the two permeable walls 5, 5' can be mounted internally in an already assembled frame 2. A first filtration stage can thus be formed to separate gases. A reference plane P of this first filtration stage can extend into the chamber V, intermediately between the 2 walls which extend parallel to each other. The device 1, optionally while retaining a general cassette format, can integrate a second filtration stage in the form of a filter element 8 carried by the support / frame 2.

[0091] A compartment C1 may be delimited by the frame 2 to allow the juxtaposed mounting of the two reinforcement parts 4a and 4b. This compartment 01 may correspond to a hollow space of the frame 2, delimited at the level of a shoulder 2e (visible in figure 3A) of the frame 2 allowing the formation of a double RF fixing region.

[0092] In one embodiment of the frame-shaped support, such an inner edge or shoulder 2e makes it possible to constitute an annular seat zone where a bar structure rests, here the second reinforcing part 4b associated with the wall 5' delimiting the rear of the adsorption media layer M. A rectangular base of this reinforcing part 4b can thus come into contact on top of the edge or shoulder 2e. The first reinforcing part 4a can be placed on the second reinforcing part, possibly using spacer elements T1, T2 arranged on the periphery.

[0093] In Figures 3A and 3B, the non-limiting case of contact at the ends of the parts 4a, 4b which are adjacent to the end pieces 2a of the frame 2 is illustrated, with the use of direct contact at an edge B7 of blade-shaped bars. when a bottom fold LP 1 is formed at this end of the pre-assembled reinforced element 4a, 5 or 4b, 5'. The arrangement is compact and facilitates the addition of the filter element 8 by carrying it by the same frame 2

[0094] On the underside of the inner edge or shoulder 2e, a fixing for the second filtration stage may be provided. More generally, it may be provided to include a second filtration stage, for example in the form of a filter element 8 carried by the support / frame 2 using an annular fixing zone. Optionally, all or part of a filter medium of this second stage or an associated support structure may be fixed and / or attached to / against the support members, for example the bars 7b, 7d, which belong to the second reinforcement part 4b.

[0095] The filter element 8 may extend generally parallel to the reference plane P1 and may include, in a medium for separating solid particles, in particular fine particles, fold lines parallel to those provided in the first filtration stage. The medium may be chosen for solid particles and / or dust passing through the first filtration stage.

[0096] With reference to Figures 4 and 5, it can be seen that the filter element 8 may be of the pleated type. In options, it may be provided to integrate several different layers gathered into a single constituent block of the filter element 8. A media, for example pleated, may constitute all or part of this filter element 8, having for example on its own a level H13. Using a filter element 8 having a level H13 (filtration class H13 according to standard ISO 29463 or EN 1822 or better) for the filtration of fine particles, it is ensured that the indoor air F' admitted into the target space via the outlet 1 b of the filtration arrangement 10 including this type of device 1 with several filtration stages is cleaned.

[0097] In a case of a multi-layer structure, at least one of the other layers, distinct from a wall reinforced by the reinforcing part 4a and / or 4b, may be pleated. In the case of Figure 4, a filtration device 1 is shown with a frame 2 forming the support without a layer that can constitute a pre-filter upstream of the assembly with two permeable walls 5, 5' enclosing the adsorption media layer M. Of course, such a layer forming a pre-filter can be added in variants, possibly in a detachable and / or washable manner in a receptacle 30 such as that illustrated in Figure 5 or the like, or even further upstream (for example in an HVAC system). Such a pre-filter can be designed separately from the frame 2. By detaching separately from the panel filter arrangement 10 or by being mounted separately, it can then be selectively reused after treatment and / or washing. Effectiveness test

[0098] The structure for delimiting the adsorption chamber is compatible with good gas filtration efficiency, durable, without having too high a footprint in terms of thickness of the device 1 (remaining for example at less than 20 mm for the adsorption part including the two flexible permeable walls, and less than 30 or 35 mm when an additional filter element is integrated in the cassette). The filtration device can have a cassette or panel format, not very thick. The adsorption part can have a larger air passage surface, thanks to the corrugated walls, in order to reduce the pressure drop that can be induced by the high level of mass of activated carbon (or similar adsorbent). The following table illustrates the advantage of this compact arrangement, the last column corresponding to the use of two corrugated permeable walls each having 16 folds, with a cassette / panel footprint (total height) of around 24 mm. [Table 1]

[0099] The use of a single corrugated wall can already be sufficient to increase the mass of coal significantly for a given volume flow rate, with however the risk of accentuating the pressure drop on the side of the wall with a non-corrugated geometry (even if a suitable curved geometry can also contribute to increasing the delimiting wall surface).

[0100] When two canvases forming the corrugated walls are used, with a constant spacing in this example between the walls 5, 5', an increase in the volume of coal is obtained in a given section / perimeter footprint with full use of the space between the two canvases. The reinforcing part (here with thin bars and blade-shaped bars), for example made of plastic, which supports the canvas is outside the chamber.

[0101] Control of the pressure drop is observed: - by reducing the air speed in the chamber thanks to the structure of parallel bars (distributed like a comb), which causes a slight deviation of the air flow, and thanks to the larger air passage surface; - by increasing the mass of coal (x2.8) without increasing the thickness too much (x2). In addition, this device 1 is space-saving.

[0102] It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed.

Claims

CLAIMS 1. Air filtration device (1), comprising: - a support (2) having two ends (E1, E2) distant from each other; - two air-permeable walls (5, 5'), substantially parallel to each other, each extending from one to the other of the two ends (E1, E2) of the support; - a chamber (V), intended to contain an adsorption medium (M) by a filling step, the chamber (V) being delimited before the filling step between the two air-permeable walls (5, 5'), the two air-permeable walls being adapted to extend transversely with respect to a flow of raw air (F) to be filtered entering the chamber (V) via one of these two walls (5), between the two ends (E1, E2) of the support (2); in which a first wall among the two permeable walls, flexible and / or capable of being folded, is connected to at least one reinforcing part (4a; 4b) fixed to the support (2) and connecting to the first wall selectively on a face of the first wall which is an outer face (F5; F5') with respect to the chamber (V), and in which the outer face (F5;F5') has rectilinear bottom lines (LP1) or zones in a corrugated profile of said first wall, the first wall being supported in a conformation with said corrugated profile by the reinforcing part (4a; 4b) which includes a plurality of support members secured to the first wall along the rectilinear bottom lines (LP1) or zones.; 2. Device according to claim 1, in which the outer face (F5; F5') of the first wall is connected to bars (7a, 7b, 7c, 7d) spaced apart and parallel to each other, preferably rigid, forming at least the support members in the reinforcing part (4a; 4b) and making it possible to maintain and structure the corrugated profile conformation of the first wall, and in which said bars (7a, 7b, 7c, 7d) are adapted to be selectively connected to said outer face (F5; F5'), each by a bar lateral face, preferably along a folding line made of a material constituting the first permeable wall.

3. Device according to claim 1 or 2, in which the two permeable walls (5, 5'), made of flexible material and whose conformation is of undulating profile, are each associated with a bar structure forming a respective reinforcing part (4a, 4b), so that there is provided in each bar structure: - a first type of bars, for which each bar (7a, 7b) is joined and linked to a bottom line (LP1) of the corresponding outer face (F5, F5'); and - a second type of bars, for which each bar (7c, 7d) is attached and linked to a line (LP2) projecting from the corresponding external face (F5, F5').

4. Device according to any one of the preceding claims, in which the adsorption medium (M) is stored in bulk between the two air-permeable walls (5, 5') and in the circumferential delimitation of a frame constituting all or part of the support (2), and in which a spacing between the two permeable walls (5, 5') is greater than or equal to 5 mm.

5. Device according to claim 4, in which the frame has a fixed or attached sealing part (24) for sealing an opening (02) for lateral access to the chamber (V), said opening (02) having made it possible to fill the chamber (V) with adsorption media (M).

6. Device according to claim 4 or 5, in which the two permeable walls (5, 5') each have an outer face (F5, F5') at which a corresponding bar structure, forming a reinforcing part (4a, 4b), is fixed and preferably overmolded or welded, so as to obtain two preassembled elements, and in which the frame is arranged to delimit a compartment (C1) in which are held: - a first pre-assembled element chosen from the two pre-assembled elements, comprising the first wall (5); and - a second pre-assembled element chosen from the two pre-assembled elements, comprising the other wall called second wall (5') of the permeable walls; the first pre-assembled element and the second pre-assembled element being mutually spaced by the frame, preferably by a part of the frame including two elongated sides (2b) of this frame, so that the two bar structures (4a, 4b) are located only outside the chamber (V).

7. Device according to any one of the preceding claims, in which a second wall (5'; 5) among the two permeable walls is connected to bars (7a, 7b, 7c, 7d) which form a subgroup of support members entirely distinct from the support members connected to the first wall (5; 5').

8. Device according to claim 7, in which the support members consist of bars (7a, 7b, 7c, 7d) which preferably have the same length to define an identical length of attachment on the permeable wall (5, 5') to which they are attached, and wherein the first permeable wall (5) and the second permeable wall (5') are kept spaced apart by a distance which is directly proportional or substantially equal to a predetermined spacing provided within respective pairs of bars (7a, 7b, 7c, 7d) each including: - a bar (7a; 7b) connected to a bottom line of the external face (F5; F5') of one of the first or second permeable walls; and - a bar (7d; 7c) connected to a projecting line of the external face (F5'; F5) of the other permeable wall.

9. Device according to claim 7 or 8, in which the two air-permeable walls (5, 5') are capable of forming, with the adsorption medium (M), a filtration stage for separating gases including volatile organic compounds, the two permeable walls (5, 5') being parallel and distributed on either side of the same reference plane (P1) extending in the chamber (V), and in which the support members, preferably all in the form of bars (7a, 7b, 7c, 7d), are distributed in at least two groups with a differentiation in their height (L7, L7') as measured in a direction (Z) perpendicular to the reference plane (P1).

10. Device according to claim 9, in which the filtration stage is a first filtration stage, the device (1) further comprising a second filtration stage in the form of a filter element (8) carried by the support (2) and / or attached to the support members (7b, 7d) which are connected, outside the chamber (V), to one of the permeable walls (5, 5') which has a corrugated profile, the filter element (8) being generally parallel to the reference plane (P1) and adapted to separate solid particles and / or dust passing through the first filtration stage.

11. Device according to any one of the preceding claims, in which at least part of the support members consists of partitioning bars (7a, 7b) each having: - two deflection faces oriented in opposite directions and extending parallel to each other from a first deflecting edge (B7), preferably rectilinear, to a second edge, opposite the first deflecting edge, which defines a junction zone (J5) with a rectilinear cusp line or zone obtained by pleating as a bottom line (LP1) of the first permeable wall, - an orientation of the two deflection faces opposite two adjacent portions of the first permeable wall (5, 5'), preferably rectangular, said two adjacent portions meeting at the junction zone (J5).

12. Air filtration arrangement (10) for the passenger compartment of a vehicle, comprising: - a receptacle (30) in the form of a conduit or a housing, provided with an inlet (1a) for raw air (F) and an outlet (1b) for purified air (F'); and - the filtration device (1) according to any one of the preceding claims, mounted internally in the receptacle (30), so as to separate an upstream zone (Z1) of the filtration in communication with the inlet (1 a), and a downstream zone (Z2) in communication with the outlet; in which the adsorption medium (M) is stored in bulk in the chamber (V) delimited between the two permeable walls (5, 5'), forming a layer of thickness at least equal to 5 mm, a circumference of the chamber (V) being delimited by a frame which delimits an access opening along a plane (P), on the side of the upstream zone (Z1), the frame supporting: - two air-permeable walls (5, 5') provided in the filtration device (1), by means of two respective bar structures, the one connected to said first wall (5), the two bar structures extending parallel to the plane (P) of the opening of the frame while being kept spaced from each other by the frame; and - an annular seal (J) or a sealing lip for annular contact on a complementary inner face located in the receptacle (30) and participating in separating the upstream zone (Z1) from the downstream zone (Z2).

13. A method of assembling an air filtration device (1) as defined in claim 1 or 2, the method comprising the steps essentially consisting of: - assembling, during an assembly step, a first air-permeable wall (5, 5') with a first bar structure, so as to maintain a pleated or wavy conformation of the first permeable wall, whereby a first pre-assembled element is obtained; - provide a second air-permeable wall; - surround the first pre-assembled element and the second permeable wall by a frame forming a support (2) having two ends (E1, E2) distant from each other, during a step of setting up the frame, so as to achieve a fixing which keeps the second permeable wall parallel to the first permeable wall, parallel to an opening of the frame and extending from one to the other of the two ends (E1, E2), whereby a chamber (V) delimited between the first permeable wall and the second permeable wall and surrounded by the frame is obtained; - after the step of placing the frame, filling the chamber (V) with an adsorption medium (M), preferably via an opening (02) of the frame, to form a layer made up of or based on said adsorption medium (M) which extends transversely with respect to a flow of raw air (F) to be filtered entering the chamber (V) via one of these two walls (5), between the two ends (E1, E2) of the support (2); wherein during the assembly step, the first wall is connected to bars (7a, 7b, 7c, 7d) of said structure which form support members spaced apart and parallel to each other, in order to support and structure the pleated or undulating conformation of the first wall, by making a connection of the bars on the first wall by a respective bar lateral face, against the same face of the first wall, and wherein the step of placing the frame is carried out in such a way that the face of the first wall on which said bars (7a, 7b,7c, 7d) or an outer face (F5, F5') relative to the chamber (V), connection of the bars on the first wall being carried out selectively on said outer face (F5, F5'), discontinuously and distributed along lines (LP1, LP2) or rectilinear zones of cusp in an undulating profile of the first wall (5, 5'), of which lines (LP1) or rectilinear zones of the bottom of the outer face (F5, F5') form part., 14. Assembly method according to claim 13, wherein the spacing (e4) between two projecting lines corresponding to two successive crest folds (LP2) in the pleated or corrugated profile of the first permeable wall (5, 5') is greater than or equal to a portion width (L) defined in the first permeable wall between one of these two crest folds (LP2) and a bottom line (LP1) corresponding to a bottom fold interposed between the two crest folds, and wherein a bar (7a, 7b) of the bar structure has a joining edge with said bottom line (LP1) extending, in a direction away from the chamber (V) which is perpendicular to the first wall, to another opposite edge (B7) projecting outwards, which is preferably projecting at least at the same level as the two crest folds (LP2).

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