Oversprayfiltermedium

Abstract

The innovation is an overspray filter medium (10), referred to briefly as filter medium (10), having at least two layers (12, 14), wherein the layers (12, 14) are not connected to one another, merely lie on top of one another within the overspray filter medium (10), and at least one layer (12, 14) has flat, punched, through-openings (16), and is provided in a separation device or for use with a separation device for filtering particles entrained with a raw gas stream from the raw gas stream.

Description

[0001] The innovation proposed here concerns the technical field of filtering particles (ranging from coarse dust to fine dust) entrained in an air stream (raw gas stream), in particular the filtering of paint or varnish particles entrained in a so-called paint mist as a raw gas stream. Paint mist that occurs when painting objects, such as vehicle bodies or the like, is also referred to as overspray in technical terminology. The overspray filter medium proposed here can also be referred to as a paint mist filter medium.

[0002] Devices for separating particles entrained in a raw gas stream, namely air stream separation devices (in short: separation devices), are already known, for example in the form of the separation device described in EP 2 532 409 B and referred to therein as a filter module or in the form of the separation device described in DE 10 2014 003 608 A1 and also referred to therein as a filter module.

[0003] Overspray separation media, namely media for separating particles entrained in a raw gas stream, are also generally known. An example is a so-called paper scrim, as mentioned in EP 2 532 409 B.

[0004] DE 20 2015 104 109 U1 discloses a web-shaped medium that functions as a filter or separation web. This web is slitted multiple times and then stretched to open the slits. The slits, opened by stretching, form openings in the medium.

[0005] Filter media with openings in at least one layer encompassed therein are also known, namely for example from WO 95 / 11073 A1, WO 2011 / 013121 A1, WO 2012 / 069172 A2 or WO 2013 / 068073 A1.

[0006] A filter medium is also known from DE 69 409 964 T2, which belongs to the patent family WO 95 / 11073 A1. This filter medium comprises two layers. One of the layers has openings created by prior slitting and subsequent stretching of the respective material. This layer is attached to another layer, for example, glued to the other layer, and the two layers together form a fluid filter.

[0007] One object of the proposed innovation is to provide a new form of an overspray filter medium, hereinafter sometimes referred to briefly as filter medium, which is intended for use, for example, with or in an air stream separation device and is in any case usable for filtering particles entrained with a raw gas stream.

[0008] The object outlined above is achieved according to the invention by means of a filter medium (overspray filter medium) having the features of claim 1.

[0009] The filter medium then comprises at least two layers, which are referred to as the first layer and the second layer for differentiation.

[0010] The layers – i.e., all layers encompassed by the filter medium; at least the first and second layers, and any additional layers, if applicable – are not connected to each other and simply lie on top of each other within the filter medium. However, this does not preclude the possibility that a single layer, or possibly multiple layers, themselves have a layer-like structure, and that the layers encompassed by these layers are connected to each other within a layer.

[0011] Each layer has an upper surface and a lower surface (surfaces), as well as a length, a width, and a thickness, with the thickness being measured between the upper surface and the lower surface, i.e., between the two surfaces. The length and width of all layers encompassed by the filter medium are the same or at least substantially the same.

[0012] Because the layers encompassed by the filter medium are not connected to one another but simply lie one upon the other, two surfaces of the successive layers within the filter medium are in contact with each other. In a filter medium with exactly two layers—i.e., a lower first layer and an upper second layer resting on top of it—the second layer rests with its downward-facing surface on the upward-facing surface of the first layer. In a filter medium with more than two layers, this applies accordingly to the remaining layers.

[0013] At least one layer of the filter medium has flat, punched, continuous openings. A flat, punched opening is different from, for example, a slot, as described in DE 20 2015 104 109 U1. In a flat, punched opening, its edge lines enclose a surface, for example, a circle, but in principle, any shape. In a slot, its edge lines lie adjacent to each other—until it expands—and do not enclose any surface.

[0014] Furthermore, a flat-punched opening is and remains an opening in the respective layer, regardless of any possible stretching of the layer. Stretching of the layer with the flat-punched openings is neither necessary nor intended. Rather, the layers encompassed by the filter medium simply lie on top of one another within the filter medium and are expressly not connected to one another.

[0015] The flat punched openings are continuous openings in that they extend from the upper surface to the lower surface of the respective layer, i.e. from one surface of the layer to the opposite other surface.

[0016] In addition to the at least one layer with continuous openings, the filter medium has at least one closed layer, i.e. a layer without continuous, punched openings.

[0017] To obtain such a filter medium (overspray filter medium), through-holes are punched into at least one of the layers, and the layers are placed on top of one another without any connection between the layers. The openings can be created entirely before the layers are laid on top of one another. The openings can also be created during the layering process, such that the openings are created spatially upstream of the location at which the layers come into contact with one another during the layering process. The layering can take place as part of a continuous or quasi-continuous process, such that the at least two layers each run off a roll or the like, and the resulting combination is then separated into individual filter media by cutting transversely to the longitudinal direction.The stacking can also be done by cutting the at least two layers to the desired length before stacking them and placing them flush on top of each other.

[0018] Advantageous embodiments of the innovation proposed here are the subject matter of the further claims. References within the claims indicate the further development of the subject matter of the referenced claim through the features of the respective dependent claim. They are not to be understood as a waiver of the right to independent protection for the features or combinations of features of a dependent claim. Furthermore, with regard to the interpretation of the claims and the description, if a feature in a dependent claim is specified in more detail, it must be assumed that such a limitation is not present in the respective preceding claims or in a more general embodiment of the device in question. Accordingly, any reference in the description to aspects of dependent claims is to be expressly read as a description of optional features, even without a specific reference.

[0019] In an advantageous embodiment of the filter medium proposed here, at least the or each layer having continuous openings is made of an air-permeable material with filtration properties (the layer consists of an air-permeable material with filtration properties or comprises an air-permeable material with filtration properties). Examples of such a material are generally all materials with or made of natural and / or synthetic fibers, in particular high-loft, nonwoven, fluid-permeable padding, stabilized, high-loft, nonwoven, fibrous media, or materials made of natural and / or synthetic fibers, such as glass, cotton, polyester, or propylene, as well as metal mesh, synthetic fibers, glass fibers, paper scrims, or natural fibers such as hemp and coconut shells.Optionally, all layers comprised by the filter medium proposed here are made of such materials, in particular, all layers comprised by the filter medium proposed here are made of the same material. The or each layer without through-openings is at least air-permeable and is made of or comprises a corresponding material, for example, a material as mentioned above.

[0020] In a preferred embodiment of the filter medium proposed here, a special design of the at least one layer with through-openings is provided, or such a special design of at least one of several layers with through-openings is provided. This special design consists in the layer, or at least one of the layers, having at least one continuous region running in the longitudinal direction of the respective layer and free of openings. Such a region free of openings is referred to here and below as a web.

[0021] The layers encompassed by the filter medium lie on top of each other. Each layer can itself consist of two or more layers. However, because the layers are only stacked and not connected to each other, each layer within the filter medium can be lifted off from a layer below it. This does not prevent the layers from being temporarily fixed relative to each other, for example, by means of stitching threads or the like. The layers are then nevertheless not connected to each other, because after the removal of such means, the layers are once again completely independent of each other, yet still lie on top of each other.

[0022] Each layer has a thickness measured in one spatial direction and a width and length measured in the other two spatial directions. Each layer is in the form of an elongated sheet, i.e., the length of the layer is significantly greater than its width, for example, at least twice as large or more than twice as large. The longitudinal direction of a respective layer or sheet runs in the direction of its greatest extent. In this longitudinal direction, the respective layer having continuous openings has at least one web.

[0023] At least one continuous web of this type advantageously prevents the respective layer from stretching in the longitudinal direction, and the shape of the through openings encompassed by the layer thus remains stable. If stretching of the layer were possible without at least one such web, stretching would not only change the shape of the openings, but the stretching would also lead to a reduction in the width of the (stretched) layer. A reduction in width may be accompanied by the possibility of air flow around the layer on its long sides. If air flow around a layer on its long sides, the filtering effect is no longer present, and color particles can pass through the layer on its long sides.

[0024] In an advantageous embodiment of a filter medium of the type proposed here with at least one web, the at least one layer (layer with through-openings) has the at least one web in the center. A central web is sufficient to counteract unwanted stretching. A central web absorbs any tensile forces symmetrically – unlike a single, edge-side web – and ensures sufficient shape retention of the layer.

[0025] In an advantageous embodiment of a filter medium of the type proposed here with at least one web, it is provided that the at least one layer (layer with through-openings) has the at least one web in the form of two edge-side webs. Edge-side webs, i.e. webs along the edge of the respective layer and along its entire length, have the advantage that they enable good sealing with an adjacent frame or the like, for example an adjacent frame of an air flow separation device. Especially when using the filter medium proposed here with such edge-side webs in an air flow separation device, the sealing with sections of the inner surface of a frame enclosed by the air flow separation device is important so that the raw gas flow does not flow past the sides of the filter medium and between the filter medium and the inner surface of the frame.In addition, the two edge-side webs also advantageously prevent the respective layer from stretching in the longitudinal direction and the shape of the through openings encompassed by the layer thus remains stable.

[0026] Optionally, it can also be provided that the at least one layer has a web in the middle as well as a web on each edge.

[0027] The innovation proposed here is also an airflow separation device with a filter medium of the type proposed here. The airflow separation device is intended and configured for separating particles entrained in a raw gas stream. The aforementioned EP 2 532 409 B describes an airflow separation device. The special feature of the airflow separation device proposed here is that it comprises a filter medium, namely a filter medium (overspray filter medium) as described here and below. Specifically, the airflow separation device comprises a frame and a filter medium, wherein the filter medium is arranged in the frame and the frame accommodates the filter medium.

[0028] The filter medium is in the form of an elongated web, and the filter medium comprises at least two unconnected layers that simply lie on top of one another, with at least one of the layers having flat, punched, through-holes. As already mentioned, each layer—and thus also the filter medium formed by the layers—has a thickness, a width, and a length. The length of the filter medium corresponds to the length of the layers it encompasses. The width of the filter medium corresponds to the width of the layers it encompasses. The thickness of the web / filter medium corresponds to the sum of the thicknesses of the layers it encompasses.

[0029] The frame has - like the frame in EP 2 532 409 B or at least similarly thereto - two opposing large-area openings in its side surfaces. When the air stream separation device is used to separate particles entrained with a raw gas stream, these openings function as an inlet opening and an outlet opening. The raw gas stream enters the air stream separation device and its frame through the inlet opening and there encounters, for example, one or more separation stages, but at least the filter medium. In the case of at least one separation stage together with the filter medium in the frame, the filter medium is located - with respect to a flow direction of the raw gas stream - preferably downstream of the or at least one separation stage, in particular downstream of the or each separation stage comprised by the air stream separation device. The filter medium filters the raw gas stream.The raw gas stream, freed or at least substantially freed from previously entrained particles and the like, exits the air stream separation device through the outlet opening.

[0030] The side surfaces with the inlet and outlet openings are referred to as the front and rear of the frame—just to distinguish them. The frame is, for example, cuboid-shaped, especially cube-shaped. The frame thus has—like any cuboid—three mutually perpendicular main axes. One of these main axes runs through the inlet opening and the outlet opening. The distance between these two openings (and thus the distance between the front and rear of the frame) is the depth of the frame. The width and height of the frame are measured along the other two main axes.Which dimension of the frame is to be referred to as width is defined below with reference to the filter medium and its attachment in the frame as follows: The filter medium has a width and the width of the frame is the dimension of the frame in the direction of the width of the filter medium, in particular in the direction of the width of the filter medium already completely or at least partially attached in the frame.

[0031] This defines the directions in which the depth and width of the frame are measured. The dimension of the frame along the remaining main axis is its height. The two side surfaces of the frame, whose distance defines the width of the frame, are referred to as wall surfaces for the sake of distinction. The two remaining side surfaces of the frame, whose distance defines the height of the frame, are referred to as base surfaces and individually as floor and lid surfaces for the sake of distinction.

[0032] The above applies accordingly to other possible frame shapes. Examples of other possible frame shapes are prisms with, in particular, an isosceles trapezoid as the base, or hollow cylinder segments with a circular ring sector as the base or a circular ring sector-shaped base. Hollow cylinder segment-shaped frames / air flow separation devices are described, for example, in EP 3 062 909 B1.

[0033] The filter medium, which is in the form of an elongated web, is significantly longer than its width. When the filter medium is attached to the frame, its width is aligned in the direction of the frame's width and then arranged three-dimensionally in the frame, for example in the form of a web folded over several times. This creates bends in the web or filter medium at the turning points of the web folded over several times (at the turning points of the filter medium folded over several times), and a pocket in the web or filter medium is created between each two bends pointing in the same direction. The bends and pockets point towards the inflow and outflow openings in the frame. The pockets created by the multiple folding are each delimited by mutually facing surface sections of the filter medium (web sections of the filter medium).To ensure a distance between the mutually facing surface / web sections and to keep the pockets open, spacers or spacer means are preferably provided, for example spacers which are placed on individual surface / web sections of the filter medium during the three-dimensional attachment of the filter medium in the frame.

[0034] Preferably, a width of the filter medium arranged three-dimensionally in the frame of the air flow separation device or of the filter medium to be arranged three-dimensionally there is at least slightly larger than a frame width measured between the corresponding inner surfaces of the wall surfaces of the frame. The filter medium is therefore at least slightly oversized in terms of its width compared to this frame width. Due to this oversize, the filter medium is accommodated in its three-dimensional arrangement by the frame in a snug fit. Here and in the following, "oversize" and "slightly wider" mean, for example, that the filter medium is 1% to 5% wider than the frame width measured between the inner surfaces of the wall surfaces of the frame. With this oversize, the filter medium arranged three-dimensionally in the frame seals particularly well against the adjacent inner surfaces of the wall surfaces of the frame.Particularly preferably, the filter medium arranged three-dimensionally in the frame also has such an excess dimension in relation to the height of the frame. When the frame is closed, the filter medium arranged three-dimensionally in the frame is then compressed so that the frame can be closed. With this excess dimension, the filter medium arranged three-dimensionally in the frame seals particularly well against the adjacent inner surfaces of the base and cover area of ​​the frame. This excess dimension is a question of the length of the web, the number of folds and pockets resulting from the length of the web and / or the dimension of any spacers present. To achieve this excess dimension, the length of the web and / or the dimension of any spacers present are suitably selected.

[0035] Preferably, in an airflow separation device and a filter medium arranged three-dimensionally therein, at least one of the layers encompassed by the filter medium and having through-openings has at least one through-web running in the longitudinal direction of the respective layer. Such a web can serve as a support surface on a spacer or for a spacer, particularly if the at least one layer has the at least one web in the center. In the case of two edge-side webs, these provide a particularly good seal against the adjacent inner surfaces of the frame, because in the area of ​​the webs there are (by definition) no through-openings that could even be open to the edge at the edge of a layer.Due to the presence of edge webs, there are no such openings open to the edge, and generally due to the lack of through openings in the area of ​​the webs, such a layer has sufficient material through the edge webs to provide a good seal against the adjacent interior surfaces of the frame. Here, too, a combination is possible and encompassed by the description presented here, according to which a layer with at least one web can have both a central web and two edge webs.

[0036] An exemplary embodiment of the proposed innovation is explained in more detail below with reference to the drawing. Corresponding objects or elements are provided with the same reference symbols in all figures. For the sake of clarity, in the case of elements that occur multiple times, not all elements are often designated by the respective reference symbol. In this respect, reference is made to the designated elements or to any designation of the same element in other figures.

[0037] The exemplary embodiment is not to be understood as a limitation of the invention. Rather, additions and modifications are also entirely possible within the scope of the present disclosure, in particular those that, for example, can be derived by a person skilled in the art with regard to solving the problem through the combination or modification of individual features or method steps described in the general or specific description, as well as in the claims and / or the drawings, and that lead to a new subject matter or to new method steps or method step sequences through combinable features.

[0038] It shows Fig. 1 and Fig. 2 a filter medium with two layers, Fig. 3 the layers of the filter medium Fig. 1, Fig. 2, Fig. 4 a special embodiment of a layer and Fig. 5 a snapshot of the insertion of a filter medium into a frame designed to hold it.

[0039] The representations in Fig. 1 and Fig. 2 show, by way of example and in a schematically simplified form, an embodiment of a filter medium 10 according to the approach presented here. The illustration in Fig. 1 shows the filter medium 10 in a plan view of one of its surfaces. The illustration in Fig. 2 shows the filter medium 10 in a side view.

[0040] In the side view it can be seen that the filter medium 10 comprises at least two layers 12, 14 - first layer 12, second layer 14. The illustration in Fig. 3 shows the layers 12, 14 in a side view as well as individually and at a distance from each other.

[0041] The representation in Fig. Figure 2 shows that the layers 12, 14 combined to form a filter medium 10 lie on top of each other within the filter medium 10. Thus, they each touch one another with one of their large surfaces. However, the layers 12, 14 are not connected to each other. They simply lie on top of each other within the filter medium 10.

[0042] The representation in Fig. Figure 1 shows the filter medium viewed from the surface of one of the layers 12, 14, namely, viewed from the surface of the first layer 12. It is particularly clearly visible here that the filter medium 10 proposed here is designed for at least one of the layers 12, 14—here, the first layer 12—to have flat, punched, continuous openings 16. The layer 12 with flat, punched, continuous openings 16, or generally any layer with such openings 16, is hereinafter referred to as a 3D layer 12 for differentiation.

[0043] In the illustration, only one opening 16 is designated and the reference line points to the center of the opening 16. It can be seen that the 3D layer 12 has a plurality of openings 16. In the side views ( Fig. 2, Fig. 3) the openings 16 - here also open at the sides - are illustrated by means of the shown structure of the layer 12.

[0044] The (or each) 3D layer 12 has, for example, a plurality of openings 16 that are identical in terms of their geometric shape. Diamond-shaped openings are shown in the figures as examples. Other shapes (circular openings, triangular openings, polygonal openings) are also possible. In principle, openings 16 with any desired edge lines are possible, and the shapes of well-known symbols (e.g., star, club, heart, spade, etc.) can also be considered as shapes. In fact, the respective shape of the openings 16 depends only on the tool used to create the openings 16 in the respective 3D layer 12. A punching tool, for example, can be used to create the openings 16. Another possibility for creating the openings 16 is a so-called laser cut. This shows that openings 16 of different shapes are also possible in one layer 12.Openings 16 created by laser cutting or the like are also considered / referred to as punched openings 16.

[0045] A 3D layer 12 with through-openings 16 can be combined with one or more additional 3D layers 12 with through-openings 16. Advantageously, a progression in the size of the openings 16 is provided, in that the openings 16 of a first 3D layer 12 are larger than the openings of a second 3D layer 12. With more than two 3D layers, this applies accordingly, in that at least in two 3D layers 12, the openings 16 become smaller from one 3D layer 12 to the immediately adjacent 3D layer 12. A progression in this sense is present, for example, when the size of the openings decreases from 3D layer to 3D layer. The sequence of the sizes of the openings 16 in the individual 3D layers can then be written as G1, G2, G3, G4 for four 3D layers 12 and a symbolic designation of different sizes of the openings 16 with G1, G2, G3, G4 (G1 > G2 > G3 > G4). This applies accordingly for more or fewer 3D layers.A progression in this sense also occurs when the size of the openings decreases only from one 3D layer to the immediately following 3D layer. The sequence of the sizes of the openings 16 in the individual 3D layers can then be written as Ga, Gb, Gc, Gd with a=[1..4], b

[0046] The representation in Fig. ​4 shows, with a view of the surface of its 3D layer 12, a particular embodiment of a filter medium 10 according to the approach presented here. Everything described above applies accordingly to such an embodiment. The special feature of this embodiment is that the 3D layer 12 has webs 18 (at least one web 18). A web 18 is an area free of through-openings 16; an area without through-openings 16. A web 18 runs in the longitudinal direction of the 3D layer (and thus also in the longitudinal direction of the filter medium 10). The 3D layer 12 shown as an example has three webs 18, namely a central web 18 and a web 18 at each edge. A 3D layer 12 with three (or more) webs 18 is an option. The special embodiment is characterized by a 3D layer 12 with at least one web 18 (central or edge). Optionally, two edge webs 18 can be provided.In principle, however, three webs 18 can also be considered, for example - as shown - on both sides at the edge and in the middle, or more than three webs 18.

[0047] The representation in Fig. 5 shows, on the one hand, a filter medium 10 of the type proposed here, namely its at least two layers 12, 14, and, on the other hand, a frame 20, in particular a cuboid-shaped frame, intended to receive the filter medium 10. The frame 20 has, in a manner known per se (see, for example, EP 2 532 409 B1), large openings in opposite side surfaces (front, back), which are referred to as inflow openings and outflow openings for differentiation and according to their respective functions. This applies accordingly to possible other frame shapes, as described above. The frame 20 is, for example, a frame 20 as described in EP 2 532 409 B1 and receives the filter medium 10, for example, in a similar way to that described there, namely in a three-dimensional arrangement in the form of a repeatedly turned web with spacers located between each individual web section.

[0048] The frame 20 can be, for example, a conventional or essentially conventional folding box (carton) - apart from the inlet and outlet openings - i.e., a folding box that could otherwise be used for packaging and / or shipping purposes. Possible materials for the frame 20 include cardboard, paperboard (especially solid board or corrugated board), plastic, metal (especially pyrolysis-resistant metal), or the like.

[0049] The frame 20 accommodates the filter medium 10 in a form-fitting or at least substantially form-fitting manner. This means that the frame 20 is designed with respect to the three-dimensionally arranged filter medium 10 and / or the filter medium 10 in a three-dimensional arrangement with respect to the frame 20 such that the interior of the frame 20 or an interior volume delimited by the frame 20 accommodates the filter medium 10. Apart from the areas with the inflow opening and the outflow opening, the filter medium 10 extends to every interior surface of the frame 20 or at least substantially to every one of these interior surfaces of the frame 20. Preferably, the frame 20 accommodates the filter medium 10 not only in a form-fitting manner, but also with a snug fit. For this purpose, the filter medium 10 is slightly oversized with respect to the interior of the frame 20 or the interior volume delimited by the frame 20.

[0050] In a method for obtaining a filter medium 10 according to the approach proposed here, flat, punched, through openings 16 are introduced into at least one of the layers 12, 14 and the layers 12, 14 are placed on top of one another without connecting the layers 12, 14 to one another. The representation in Fig. 3 can be seen as an example of a snapshot when placing the layers 12, 14 on top of each other. The stacking can also take place when inserting the filter medium 10 into a frame 20 intended for its reception, as shown in the illustration in Fig. 5 is shown schematically simplified.

[0051] A filter medium 10 placed in a frame 20, together with the frame 20, forms a filter and / or separation device, referred to here and below collectively as a separation device (air flow separation device). A plurality of such separation devices arranged next to and / or one above the other is typically used—as described, for example, in EP 2 532 409 B1—in a shelf-like structural element of an extraction wall or an extraction floor of a painting system or the like. As a shelf-like structural element, the structural element comprises a plurality of compartments arranged next to and / or one above the other, and each compartment is designed to accommodate a respective separation device.

[0052] Individual, prominent aspects of the description presented here can thus be briefly summarized as follows: An overspray filter medium 10, referred to here as filter medium 10, is specified, having at least two layers 12, 14, wherein the layers 12, 14 are not connected to one another and merely lie on top of one another within the filter medium 10, and at least one layer 12, 14 has flat, punched, through-openings 16. The filter medium 10 is provided in a separation device or for use with a separation device for filtering particles entrained with a raw gas stream from the raw gas stream.

[0053] Overall, the innovation proposed here is also the use of a filter medium (overspray filter medium) 10 as described above and defined in the claims, an air flow separation device with such a filter medium 10 or a painting system with at least one such air flow separation device for filtering particles entrained with a raw gas flow from the raw gas flow. List of reference symbols 10 overspray filter medium, filter medium 12 first layer, 3D layer 14 second layer 16 Opening 18 jetty 20 frames QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2 532 409 B [0002, 0003, 0027, 0029] DE 10 2014 003 608 A1

[0002] DE 20 2015 104 109 U1 [0004, 0013] WO 95 / 11073 A1 [0005, 0006] WO 2011 / 013121 A1

[0005] WO 2012 / 069172 A2

[0005] WO 2013 / 068073 A1

[0005] DE 69 409 964 T2

[0006] EP 3 062 909 B1

[0032] EP 2 532 409 B1 [0047, 0051]

Claims

[1] Overspray filter medium (10) with at least two layers (12, 14) - first layer (12), second layer (14) - wherein the layers (12, 14) are not connected to one another and merely lie on top of one another within the overspray filter medium (10) and wherein at least one layer (12, 14) has flat punched, through openings (16). [2] Overspray filter medium (10) according to claim 1, wherein at least the or each layer (12, 14) having through openings (16) is made of an air-permeable material having filtration properties. [3] Overspray filter medium (10) according to claim 1 or 2, wherein the at least one layer (12, 14) with through openings (16) or at least one of several layers (12, 14) with through openings (16) has at least one continuous web (18) running in the longitudinal direction of the respective layer (12, 14) and free of openings (16). [4] Overspray filter medium (10) according to claim 3, wherein the at least one layer (12, 14) with through openings (16) has the at least one web (18) centrally. [5] Overspray filter medium (10) according to claim 3 or 4, wherein the at least one layer (12, 14) with through openings (16) has the at least one web (18) in the form of two edge-side webs (18). [6] Air flow separation device for separating particles entrained in a raw gas flow, comprising a frame (20) and an overspray filter medium (10) received by the frame (20) according to one of claims 1 to 5. [7] Painting system with a structural element and a plurality of air flow separation devices placed in receiving compartments of the structural element according to claim 6.

Images