Air cleaner for removing air pollutants from an air stream

[0001] The present invention relates to an air purifying device that removes air pollutants from an air stream, such as a gas outlet / inlet in amusement machines, wherein the characteristic air purifier has an air filter having at least one filter layer held in the filter holder in the characteristic air flow, perpendicular to the main air flow direction and having a series of filter cartridges preferably having the shape of rods adjacent to each other.

[0002] An air purifying device of the known type is known from WO 2007/028176 A1 describing a filter device for removing air pollutants at the outlet of a device. This known device is equipped with a series of rod-shaped filters, attached at opposite ends in the filter housing and organized in a series of layers, one above the other, showing lateral displacement between the layers. The characteristic rod-shaped filter cartridges are made of a porous material such as plastic foam, moistened with a liquid such as silicone oil. These types of wet filters are a very effective solution to remove air pollutants, including ultra-fine particles and gaseous pollutants such as unpleasant odors, which are chemically absorbed and neutralized when they come into contact with liquid. A series of rod-shaped filter cartridges are enclosed in a filter housing forming a tube-like channel in which the filter cartridges are mounted. This pipe-like duct is intended to direct the flow of contaminated air through the system of filter cartridges and to prevent air from leaking out of the filter cartridges. This arrangement of filter cartridges, however, is disadvantageous in some embodiments, for example, it has turned out that the individual filter cartridges are loaded to varying degrees, in particular the filter load on the inner cartridges differs from the filter load on the external cartridges. In addition, this arrangement of filter cartridges is sensitive to the air flow rate.

[0003] Another filter device having wet filter cartridges for cleaning the exhaust air from office equipment is known from EP 1 345 669 and suggests keeping the filter cartridges vertically at their opposite ends so that the wetting fluid of the cartridges flows downwards along the cartridges filter, under the influence of gravity. The oil liquid is stored in the chamber above the filter cartridges, characterized in that the oil cartridge may be in the chamber.

[0004] In addition, EP 0 515 759 A1 describes an air filter device equipped with a cylindrical housing, the front and back of which are covered with mesh, whereby the purified air can flow through the housing in which the filter body, which may contain pellets, is placed. carbon. The filter housing is located on the back of the fan motor directing the air flow to the front, open plane of the filter housing.

[0005] The present invention aims to improve the said filters and to avoid the associated disadvantages. The object of the present invention is to provide an improved device that cleans the air of air pollutants present in the air flow, such as the air inlet / outlet, with high efficiency and equipped with a small size filter enabling its placement, for example, in a small interior.

[0006] According to the present invention, this object is achieved thanks to the air purifying device according to claim 1 and the amusement machine according to claim 15. Advantageous embodiments of the present invention are described in the dependent claims and explained in more detail below.

[0007] The filter device may not have a closed environment around the periphery of the filter layers, but it has an open side along at least a portion of the periphery of the filter layer. At least one fragment of the peripheral, lateral part of the filter layer parallel or tangential to the longitudinal axis of the outermost filter cartridge is formed as an open side without flow control elements surrounding the filter layer. In contrast to prior art solutions in which the filter layer is generally enclosed in a flow channel having the form of a tube, the present invention avoids the use of such flow control elements directing the air flow through the filter layer and / or preventing air flow divergence from filter layers, characterized in that, in particular, the filter layer on its open side has flow control elements, such as flow control surfaces, flow channel walls, fences, or enclosing walls surrounding a filter layer. Interestingly, such an open side increases the cleaning efficiency of the outermost cartridges because it is assumed that the flow disturbances are weaker there, and the air flows around the outermost elements in a more laminar way, without excessively high flow rates, which allows better absorption of air pollutants. Since the air flow is not accelerated through the housing channel with a limited cross section, but it can also diverge towards the periphery of the filter layer as it flows through the filter device, the outermost filter cartridges exhibit greater efficiency and thus provide a more uniform distribution of the filter load between all filter cartridges. In addition, the filtering device has a very compact structure with small dimensions, allowing the location of the air purifying device in small spaces, such as the inside of amusement machine cabinets.

[0008] The support device preferably has a rod or beam shape with which all filter cartridges forming the filter layer are rigidly connected. The holder preferably extends over the entire width of the filter layer, it is characterized in that the longitudinal axis of the holder can extend in a direction perpendicular to the longitudinal axis of the filter cartridges. However, according to another embodiment of the invention, the handle may extend diagonally through the filter elements, such that the longitudinal axis of the handle is at an angle relative to the longitudinal axis of the finltra inserts at an angle of about 30 ° to 90 °, preferably 30 ° to 60 °.

[0009] Filter cartridges may be supported at both ends by a pair of handles. In accordance with this embodiment, greater crack resistance of the filter cartridges is achieved. The end elements of the filter cartridges are rigidly connected to the respective holders, so that the opposite opposing sides of the filter layer are closed by the holders. However, the remaining fragments of the perimeter of the filter layer, i.e. the peripheral sides parallel to the longitudinal axis of the filter cartridges, may be open, without handles or fences or enclosure walls surrounding the filter layer.

[0010] In general, there may be different connections between filter cartridges and the characteristic holder. For example, the handle may have holes resembling holes corresponding to the cross-sectional shape of the filter cartridge. However, according to a preferred embodiment of the present invention, the at least one rod or beam-shaped handle has a bearing surface in which the filter cartridges with a supporting surface are embedded, characterized in that preferably, the supporting parts of the filter cartridges are only partially embedded in the supporting surface, thanks to why another part of the peripheral side of the filter cartridge projects from the bearing surface. Due to the presence of an unbuilt fragment (i.e. the non-built-in part) of the supporting part of the filter cartridges, the active surface of the filter is increased and the filter cartridges can absorb air pollution even on their supporting part, which ensures increased filter performance, regardless of the presence of the open side of the filter layer. To balance the desired increase in effective filter surface with the necessary supporting force, part¹Λπ to 3/2 π circumference of the supported part of the filter cartridges can be built into the support surface of the holder. Preferably, a circumference of 1π of the circumference is built-in, which allows easy removal of both the filter insert and the holder from the mold.

[0011] The holder may be formed of a material other than the material of the filter cartridges, it is characterized in that the support surface of the holder may have contours adapted to the shape of the peripheral side of the embedded filter cartridges so that the filter cartridges nest against the contours of the support surface. For example, if the filter cartridges have a cylindrical shape with a circular cross-section, the support surface of the handle may have a recess in the form of a groove with a cylindrical contour. To connect the filter cartridges to the holder, they can be pasted into the fixing contours.

[0012] According to another preferred embodiment of the invention, the holders can be formed with integrated filter cartridges in the form of one piece made of the same material, characterized in that sintering can advantageously be used to obtain it. In a further embodiment of the invention, the filter cartridges and the holder may be formed, potentially, in a foam forming process. For such an integral, one-piece structure of the handle and filter cartridges, said cantilever support structure is advantageous because it facilitates the removal of mold halves from the molded filter and cartridge cartridges. In particular, the one-piece structure including the handle and filter cartridges may have a shape without undercuts and meshing in the direction of the longitudinal axis of the filter cartridges and / or in the direction perpendicular thereto. In other words, the one-piece structure comprising the filter cartridges and the handle may be shaped such that there is a dividing plane, preferably extending perpendicular to the longitudinal axis of the filter cartridges. Preferably, all filter layers of the filter layer are formed as one piece with the handle (s) mounting the filter layer, they are characterized in that even filter cartridges of more than one filter layer can be formed as one piece with their handle.

[0013] Basically, different materials can be used to form the filter cartridges and, optionally, the holder, wherein according to a preferred embodiment the filter device is a wet filter device having a suitable liquid wetting the material of the filter cartridge construction. In other words, filter cartridges can be designed as a carrier medium for a chemically and / or physically active liquid that adsorbs or absorbs air pollutants. Advantageously, fluids such as oils, emulsions or liquids can be used, depending on the type of impurities present in the purified air. Optionally, antibacterial, antiviral, antifungal or fungicidal agents may be added to the wetting fluid. The basic material of the wetted filter cartridge may comprise various, preferably porous materials such as plastic foams, organic, inorganic or natural fibers such as cellulose or polyester, characterized in that in the preferred embodiment filter cartridges made of wetted PU foam are used silicone oil.

[0014] To allow the filter to be easily adapted to various operating conditions and to change the size and effect of the filtering surface, the filtering device is provided with a modular structure consisting of basic elements that can be combined with each other in a variable number and / or in a different orientation. According to a preferred embodiment of the invention, the filter cartridge fixing handle is designed such that it can be connected to an identical shape holder. In particular, the handle is equipped with a collarbone joint enabling at least two filter holders to be joined together to form two filter layers, one above the other. This means that it is possible to create stacks of filter layers simply by joining together the desired number of handles, each of which fixes a filter layer consisting of multiple filter cartridges.

[0015] To avoid configuring the filter cartridges in different filter layers in orientation one after the other, it is preferable to position the filter cartridges offset from said zwitterion in such a way that - when the two filter holders are connected together - the filter cartridges in the first filter layer cover with the spaces between the filter cartridges in the second layer, viewed from the airflow direction.

[0016] According to a particularly preferred embodiment, the characteristic support member of the handle has a characteristic double-shaped joint at the rear, opposite to the bearing surface in which the filter elements are embedded. Then, the two beam-shaped handles can be connected to each other so that their back planes face each other.

[0017] The rod-shaped filter cartridges may have substantially different geometries and shapes, for example, a length to diameter ratio greater than 5, in particular greater than 10, which means that the rod-shaped filter cartridges may have a length of at least five times the diameter filter cartridge. The cross-sectional shape can also be changed and can be adapted to the operating conditions. For example, the filter cartridges may have a triangular or multi-walled cross section, characterized in that in particular they may have a rectangular or rounded cross section. However, in accordance with a preferred embodiment of the invention, it is preferred that the filter cartridges have a rounded cross section, e.g., circular, oval or elliptical, allowing a smooth flow around the filter cartridges to enhance the absorption of contaminants.

[0018] According to a preferred embodiment of the invention, the filter cartridges are practically straight rods arranged parallel to each other in the filter layer. If the filtering device has several filter layers, the filter rods in different layers may be arranged in parallel with each other, so that the filter rods in different layers are shifted relative to each other so that the filter rods in the first layer match the voids between the filter rods in the second guard, looking in the direction of air flow.

[0019] The invention includes indirectly assembling the filter layer. According to an embodiment of the present invention, the filter layer of the filter device is placed in the mounting frame surrounding the filter layer around its periphery, the characteristic mounting frame has a recess completely overlapping with the predicted area of ​​the filter layer, looking in the direction of air flow, which allows insertion and removal of the filter layer in / out of the mounting frame, in the direction of air flow. Unlike solutions known in the art, this mounting structure significantly facilitates assembly, disassembly and replacement of the filter layer, as there is no need to screw the filter cartridges into the mounting recesses separately, which is the case with the described solutions, where the filter cartridges are placed in the direction perpendicular to the air flow direction and / or parallel to the direction of the stick rods of the filter.

[0020] The mounting recess in the mounting solution may have a window-shaped opening, roughly corresponding to the shape or circumference of the filter layer placed therein. Preferably, the attachment recess is defined by a cylindrical through hole through the mounting frame, characterized in that the inner periphery of the through hole essentially corresponds to the outer perimeter of the filter layer, such that the filter layer is trapped in the mounting depression. The mounting recess does not hold each side or the entire perimeter of the filter layer, but only holds the filter on opposite sides. If the filter layer consists of a series of parallel, practically simple rod-shaped filters, it is preferable to press into the mounting recess at the ends of the characteristic rod-shaped elements, while the other two sides of the filter layer parallel to the longitudinal axis of the cartridges may remain a short distance from the surrounding recess mounting. According to the invention, pressing the ends of the rod-shaped filters into the mounting holes and / or holders located at these ends of the rod-shaped filters in the mounting recess, uses the rod-shaped filters as columns or compression posts subject only to bending stress.

[0021] The air purification device is preferably located inside a cabinet, for example a gambling or entertainment machine, whereby the air is filtered inside the machine housing.

[0022] Amusement machines such as coin-operated gambling machines generally work in casinos and gambling rooms where the air is often polluted due to smoking, sweating people or the smell of food. Another problem is the exhaust gases produced by amusement machines, which are often equipped with electronic controllers and displays that produce hot exhaust air, often contaminated with dust or other particles. Thus, it would be beneficial to clean the air in rooms where such amusement machines are used, where it would be desirable to clean the inlet air to machines in order to avoid damaging the sensitive elements of the amusement machines, and, on the other hand, to clean the exhaust gases of such amusement machines to improve the air condition in the room where slot machines are working to improve the comfort of players using amusement machines.

[0023] This means that the air purifying device cleans both the inlet and the outlet of the entertainment machine, thereby improving the air quality in the casino or gambling room, thereby improving the comfort of visitors, and on the other hand, protects the electronic components of the entertainment machine from settling impurity particles present in the intake air. Although an air purifier is preferably used for the entertainment machine, it also has other potential applications. For example, an air cleaning device can be used in other office equipment, such as laser printers, for household appliances such as vacuum cleaners. Another preferred field of application are vehicles, in particular cars, in which the air purifying device can be used to clean the air in the passenger cabin or in the air field of air conditioning and heating systems, in vacuum cleaners and other household appliances that can use filters, in military equipment, aviation, industry steel and heavy metals, etc. Another advantageous field of application is the production of medicines in the medical industry.

[0024] The preferred embodiments of the present invention are described in more detail below, with reference to the respective drawings. The drawings show that:

Figure 1: a perspective view of a filter device in accordance with a preferred embodiment, characterized in that the rod-shaped filter cartridges are arranged in parallel with each other and are held in place by a handle at opposite ends,

Figure 2: a perspective view of the filter device shown in the figure, characterized in that the filter device is mounted on a fan forcing the air flow through the filter layer, characterized in that the filter cartridges are shown in an in-use condition with visible contamination of the filter cartridges,

Figure 3: a preferred embodiment of the fastener of the holder for the filter cartridges, characterized in that part of Figure 3 is a perspective view of the beam-shaped holder as such, i.e. without filter cartridges attached to it, whereby the groove-shaped support surface of the holder is visible, and part b of figure 3 shows a front view of the holder with filter cartridges mounted in the support surface of the holder.

Figure 4: Front view of the handle with rod-shaped filter inserts connected to the handle similar to figure 3, characterized in that the embodiment of figure 4 shows a slightly bent, still retaining the beam shape element having elastic properties and having a slightly concave rear surface in an unbent condition .

Figure 5: Front view of two handles with filter cartridges mounted in them and in contact with the rear in a retracted position, ready to connect two handles to them, characterized in that the zwitterions are shown.

Figure 6: Front view of the two fasteners of Figure 5, after being joined together.

Figure 7: a front view of two handles joined together in a similar manner to Figure 6, characterized in that the connecting solutions have through-drilled holes in both handles, which can be attached to each other by placing the mounting pins into the characteristic hollow holes,

Figure 8: Extensive view of two straight layers of filter cartridge rods held together by two attachment members at the ends, characterized in that the attachment members are provided with bearing surfaces on their opposite sides in which the filter inserts are placed.

Figure 9: Perspective view of a series of simple rod-shaped filters arranged in two layers, one above the other, with a handle attached to the central parts of the characteristic rod-shaped filter cartridges, which thus have two free, non-supporting horizontal.

Figure 10: Front view of the filter device of Figure 9 in the direction of air flow through the filter,

Figure 11: Front view of the ventilation solution forcing air flow through the filter,

Figure 12: A front view of the filter device of Figure 10 combined with the ventilation of Figure 11,

Figure 13: Plan of a filter layer similar to Figure 8 placed in the recess of the mounting frame for indirectly mounting the filter layer in the air stream.

[0025] Figure 1 shows a filter device 1 having a series of filter cartridges 5 formed in this example by simple rod-shaped filter cartridges 13. The filter cartridges 6 form a first filter layer 4a and a second filter layer 4b, one above the other, characterized in that the cartridges filter 6 extend practically parallel to each other. As can be seen from Figure 1, Figure 6 and Figure 7, the filter cartridges in the various layers are preferably offset relative to each other, so that the filter cartridges 6 in the first layer 4a overlap with the voids between the filter cartridges 6 in the second layer 4b. In particular, both filter layers 4a and 4b may have the same division between filter cartridges, characterized in that the offset perpendicular to the longitudinal axis of the filter cartridges corresponds to half the distance between two adjacent filter cartridges, cf. Figures 6 and 7.

[0026] Although the filter cartridges and the dividers may have different dimensions, the distances between adjacent filter cartridges 6 in one layer 4 have a width preferably and approximately corresponding to the diameter of the filter cartridge 6, see Figure 7. This means that if two layers 4a and 4b were in a common plane, the filter cartridges 6 would touch each other and form a closed panel. However, other structures and / or division between filter cartridges are also possible, which allows the formation of other geometric structures.

[0027] As can be seen in figures 6 and 7, the distance between the filter cartridges 6 in different filter layers 4a and 4b can also be a distance in the diameter range of the rod-shaped filter cartridges, characterized in that it is a preferred solution that the distance between the top edge of the first layer and the lower edge of the upper layer, measured in the direction of air flow, is slightly smaller than the diameter of the filter cartridges. Although different filter cartridges may have different diameters, it is preferable to keep the same diameter for all filter cartridges. As the figures show, the filter cartridges may have a cylindrical shape with a round cross-section.

[0028] According to a preferred embodiment, the filter cartridges 6 of the filter layer 4a are held in place by a filter holder 5 having at least one attachment element 9 preferably having the shape of a beam or rod, as shown in the figures. More specifically, the fixing element 9 can be used as a bearing surface 10 in which filter cartridges 6 with peripheral walls and supporting elements 6d are placed.

[0029] As shown in figure 3, the bearing surface 10 of the mounting element 9 may have contours adapted to the contour of the filter element circumference 6. In particular, the characteristic bearing surface may have grooves in the shape of grooves in which the supporting elements 6d of the filter inserts 6 are nested, that there is two-dimensional contact between the filter elements 6 and the fixing element 9. If cylindrical rod-shaped filter inserts are used, the recesses in the bearing surface 10 of the fixing element 9 may be formed as cylindrical bearing grooves.

[0030] As can be seen from figure 3, the filter cartridges 6 are located in the bearing surface 10 of the mounting element 9 only partially so that a portion of the peripheral surface of the filter cartridges 6 is secured in the mounting element 6 while the remaining part of the peripheral surface of the filter cartridges is not is placed and / or can protrude above the bearing surface 10. For the embodiments shown in the figures, the filter cartridges 6 are located in the mounting element 9 by half their diameter. In other words, a 1/2 π part is built in, see figure 3.

[0031] The rear surface of the fastening element 9 opposite the built-in filter elements 6 forms a practically flat mounting surface 11 allowing the two fastening elements 9 to be joined together by rear planes, as shown in figures 5-7. In this way a modular filter 6 is created, characterized in that the multiple layers of the filter 4 can be stacked on top of each other easily.

[0032] As shown in figures 5 and 6, the fastening element 9 can be provided with a twin-connector 12, allowing the identically formed fastening elements 9 to be joined together. For the embodiments shown in figures 5 and 6, the twin-connector 12 has a connecting pin 32 and a connecting hole 33 on opposite sides of the bearing surface 10, characterized in that the connecting pin 32 and the connecting hole 33 are at the same distance from the element 9 so that the fastening elements 9 can be mounted on top of each other in a consistent manner.

[0033] As can be seen from the example of Figures 5 and 6, the filter cartridges 6 are offset relative to the center of the fastener 9 and / or the center of the joints by connectors 12, characterized in that the offset is perpendicular to the longitudinal axis of the filter cartridge 6. In particular, the significant shift is such that the filter cartridges 6 of one layer 4a overlap with the voids 17 between the filter cartridges 6 of the outer filter layer 4b when the two fasteners 9 are installed and connected together as shown in figure 6.

[0034] To reinforce the frictional force blocking both fasteners 9, the latter can be made of flexible material and / or have a slight bend in figure 4, due to which they undergo plastic deformation when combined with another fastener 9.

[0035] As an alternative to the connecting pin 32 and the connecting holes 33 shown in Figures 5 and 6, other connecting elements 12 can also be provided. For example, the fastening elements 9 can be provided with through holes 34 in which the connecting pins or screws can be placed or other connecting elements as shown in figure 7. Preferably, the characteristic through holes 34 are arranged such that the through holes of the various fastening elements 9 are mutually coordinated when the distinctive different fastening elements 9 are arranged side by side in a coherent manner with the back planes facing each other.

[0036] As can be seen in figure 8, two fastening elements can be connected to opposite ends 6a and 6b of the filter cartridges 6 so that both ends of the filter cartridges 6 are supported and seated in place.

[0037] In the alternative embodiment shown in figure 9, the filter cartridges 6 are supported on brackets, whereby the filter cartridges 6 have free, unsupported terminals 6a and 6b. As can be seen in Figure 9A, a single carrier can be connected to the central portion 6c of the filter cartridges 6, so that the filter cartridges 6 have free, unsupported terminals 6a and 6b. Such bracket-based support of the filter cartridges 6 not only reduces the size of the filter holder 5, but at the same time increases the effective filtering surface of the filter cartridge 6, and facilitates the production of the filter cartridge 6 and mounting element 9 in the molding process. In particular, such a support structure as shown in figure 9 facilitates the step of removing the mold and the mold halves from the filter cartridges 6 and the mounting element 9, even when the filter cartridges 6 and the mounting element 9 form an integrated, single element. As can be seen from Figure 9, the one-piece structure including the fastener 9 and the filter cartridge 6 may have a shape without undercuts and depressions in the direction of the longitudinal axis of the filter cartridges, so that there is a dividing plane perpendicular to the longitudinal axis of the rod-shaped filter cartridges.

[0038] As can be seen in figures 9b and 9c, the mold halves 29 and 30 used for sintering the filter cartridges 6 and the fastener 9 in one piece can be removed by moving the halves 29 and 30, set apart, in a virtually equal direction longitudinal axis of 25 filter cartridges 6.

[0039] In order to maximize the effective filter surface, the mounting element 9 can be made of the same material as the rod-shaped filter cartridges, which further facilitates the cooling process. However, even when a significant integral one-piece structure is provided, the fastener 9 and filter cartridge 6 can be made of various materials, for example in a two-component molding process. This allows the fastener 9 to be made of a more rigid material and / or reinforced material.

[0040] Figures 10-12 show an embodiment in which a series of simple rod-shaped filters 13 have received support in the form of a common support beam in the central part 6c, similar to the embodiment in figure 9. In contrast to the embodiment shown in figure 9, filter cartridges 6 are fixed in the bearing surface 10 of two fastening elements 9, connected to each other by back sides, as explained with reference to figure 7.

[0041] In order to pass the purified air through the filter 1, a ventilation element 2 can be provided, the ventilation element 2 has a ventilation wheel 19 rotating about the axis of the fan 20 and having a series of fan blades 15 connected to the axis of the fan 20. Furthermore, the ventilation solution 20 has a drive unit 16, which can generally be an electric motor mounted inside the housing 21, supported on the drive unit handle.

[0042] The filtering device 1 is arranged before the ventilation solution 2 with the filter layers 4 practically perpendicular to the axis of the fan 20 and / or perpendicular in the main direction of the air flow created by the fan blades 15. In the embodiment shown, the filter 1 is positioned in front of the ventilation wheel 19 , alternatively or additionally it can be positioned at the rear of the drive unit 16 opposite the ventilation wheel as shown in figure 18. Thanks to this solution (s), the filter 1 can replace any protective grille that may be required as protection against undesirable contact or contact, of the fan blades 15, especially when the element is rotating.

[0043] As shown in Figure 13, a mounting frame 26 is used, which may have a ring enclosed in a ring, as already shown in Figure 13, but it may also have an open configuration, for example by having two or three of the four legs 31 of the mounting frame 26 of Figure 22. The characterizing mounting frame 26 is provided for the purpose of indirectly mounting the layer 4 filter to any suitable support structure, such as the characteristic fan drive unit.

[0044] As shown in Figure 13, the mounting frame 26 has a mounting recess 27 that completely coincides with the provided area 28 of the filter layer 4 when viewed in the direction of airflow 3 and / or perpendicular to the plane defined by the filter layer 4. This allows the layer to be removed and removed filter 4 from the mounting frame 26 in the direction of air flow 3 and / or perpendicular to the plane defined by the filter layer 4.

[0045] Preferably, the size and / or dimensions of the attachment recess 27 are selected according to the size and / or dimensions and / or shape of the filter layer 4, such that the filter layer 4 is embedded in the attachment recess by pressing. In particular, the width of the mounting recess 27 corresponds to the length of the filter layer 4 towards the longitudinal axis of the straight rod-like filter cartridges. This means that the rod-shaped filter cartridges can be used as pressure columns to provide the necessary friction at the ends of the rod-shaped filter cartridges to secure the filter layer 4 to the mounting frame 26. In the transverse direction, i.e. perpendicular to the longitudinal axis of the sticky filter cartridges, the mounting recess can be formed wider than the filter layer 4, so that the rod-shaped filter cartridges positioned perpendicular to its longitudinal axis are not pressurized.