Air filtering device

Abstract

The invention concerns an air filtering device (1) comprising: a housing (2), a separator plate (3) that separates an interior of the housing into an unclean compartment (4) and a clean compartment (5), a first filter aperture (6), a mounting arrangement configured to allow mounting of a first replaceable air filter (100) at the first filter aperture (6), an air inlet (8) for uncleaned air and an air outlet (9) for clean air, wherein the mounting arrangement comprises first and second moveable rail members (10, 11) exhibiting a supporting surface (10A, 11A) directed towards the clean compartment (5), wherein each supporting surface (10A, 11A) is arranged to form a support for a corresponding flange (101, 102) arranged on an outer side (103) of a filter end structure (104) of the first air filter (100), wherein the first and second rail members (10, 11) are connected to an actuator system (12, 13, 14) located in the clean compartment (5) of the housing (2), wherein the actuator system (12, 13, 14) is configured to set the first and second rail members (10, 11) in: i) a first position where the supporting surfaces (10A, 11A) are located at a distance from the separator plate (3); and ii) a second position where the supporting surfaces (10A, 11A) are located closer to the separator plate (3) than in the first position and / or are located at the clean side (5) of the separator plate (3) so as to press the outer side (103) of the filter end structure (104) of the first air filter (100) against the separator plate (3) around the first filter aperture (6).

Description

[0001] Air filtering device

[0002] TECHNICAL FIELD

[0003] This invention relates to an industrial air filtering device for removing dust, dry particles and similar from a flow of air. The invention also relates to an air filter for use in such a device.

[0004] BACKGROUND OF THE INVENTION

[0005] Industrial air filtering devices / dust collecting systems for removing dust, dry particles and similar from a flow of air are used in a variety of industrial facilities. Such devices generally include a housing, a separator plate dividing an interior of the housing into an unclean compartment and a clean compartment, one or more openings in the separator plate allowing air to flow from the unclean compartment into the clean compartment, one or more replaceable air filters arranged at corresponding openings in the separator plate, a main air inlet for uncleaned air arranged in fluid communication with the unclean compartment, a main air outlet for clean air arranged in fluid communication with the clean compartment and a dust collecting compartment usually arranged in a lower portion of the housing.

[0006] An example of such an air filtering device is disclosed in US2013 / 0091811A1.

[0007] Although a device of the type exemplified in US2013 / 0091811A1 works well in principle, there is a general need for improvements, for instance with regard to installation and removal of the air filter, operational performance as well as production efficiency (reduction of cost and time).

[0008] SUMMARY OF THE INVENTION

[0009] The invention concerns an air filtering device for removing dust, dry particles and similar from a flow of air, said device comprising: a housing, a separator plate that separates an interior of the housing into an unclean side with an unclean compartment and a clean side with a clean compartment, at least a first filter aperture in the separator plate allowing air to flow from the unclean compartment into the clean compartment, a mounting arrangement configured to allow mounting of a first replaceable air filter at the first filter aperture at the unclean side of the separator plate so that air flowing from the unclean compartment into the clean compartment via the first filter aperture is forced to flow through the first air filter when installed in the air filtering device, an air inlet for uncleaned air arranged in fluid communication with the unclean compartment, and an air outlet for clean air arranged in fluid communication with the clean compartment.

[0010] The mounting arrangement comprises first and second moveable rail members that extend along opposite sides of the first filter aperture, wherein each of the first and second rail members exhibits a supporting surface directed towards the clean compartment, wherein each supporting surface is arranged to form a support for a corresponding flange arranged on an outer side of a filter end structure of the first air filter.

[0011] The first and second rail members are connected to an actuator system located in the clean compartment of the housing, and the actuator system is configured to set the first and second rail members in: i) a first position where the supporting surfaces are located at a distance from the separator plate at the unclean side thereof so as to allow positioning the first air filter in relation to the first filter aperture in the separator plate by moving the first air filter and its flanges along the supporting surfaces; and ii) a second position where the supporting surfaces are located closer to the separator plate than in the first position and / or are located at the clean side of the separator plate so as to, when the first air filter is arranged with its corresponding flanges positioned onto said supporting surfaces, press the outer side of the filter end structure of the first air filter against the separator plate around the first filter aperture. An air filtering device of the above type allows a new air filter to be installed in a two-step process where the filter in a first step is arranged with its flanges located at the rail member supporting surfaces without being fixed to the device, which means that the position of the air filter can be adjusted along the rail members so as to align the air filter with the filter aperture, and where the filter in a second step is fixed to the device by activating the actuator system and setting the rail members in the second position. Removal of the air filter is carried out in the reverse order. This provides for easy installation and removal of the air filter. A further advantage is that the actuator system is located in the clean compartment and thus not exposed to the dust present in the unclean compartment.

[0012] When the rail members start to move from the first position towards the second position, the supporting surfaces move closer to the separator plate and thus move the air filter closer to the separator plate. When the rail members reach the second position, the supporting surfaces are typically closer to the separator plate than in the first position. However, depending on the specific design of the rail members, which e.g. depends on the design of the flanges of the filter end structure, it may be that the rail members extend through the filter aperture and into the clean compartment so that the supporting surfaces become located relatively far into the clean compartment when the rail members reach the second position, i.e. further away from the separator plate than when the rail members are in the first position.

[0013] The above air filtering device design is particularly advantageous when the clean compartment is located above the unclean compartment with the separator plate oriented horizontally, the rail member supporting surfaces face upwards, and the air filters are to be installed in a vertical manner with the filter end portion forming a top portion. In such a case the air filter can be suspended onto the rail members with the flanges placed onto the supporting surfaces, and the air filter can easily be moved in a sliding manner along the rail members for alignment with the filter aperture. The first and second moveable rail members typically extend in parallel along the opposite sides of the first filter aperture.

[0014] In an embodiment, the actuator system comprises first and second rotatable shafts extending along opposite sides of the first filter aperture and substantially in parallel with a corresponding rail member, wherein each rail member and / or its connection to the actuator system extends through the filter aperture and connects to a corresponding rotatable shaft so that rotation of a shaft leads to a movement of the corresponding rail member that forces the supporting surface to move towards or away from the separator plate depending on the direction of the rotation.

[0015] The first and second rotatable shafts are thus located in the clean compartment. Rotation of the shafts may be achieved manually. To avoid having to rotate the shafts individually, the two shafts may be connected via a mechanism that causes both the first and second shaft to rotate (in different directions) simultaneously, e.g. when rotating a single additional shaft connected to the first and second shafts. Alternatively, rotation of the first and second shaft may be achieved by electric motors or hydraulic or pneumatic equipment.

[0016] The rail members may have the form of folded sheet metal plates where one edge or side end part of the plate extends along the corresponding rotatable shaft and is fixed thereto and where the opposite edge or side end part forms the supporting surface. When the shaft is rotated also the entire folded sheet metal plate rotates. If the supporting surface is fixed to the shaft by such a rigid connection and if the supporting surface is flat so as to be parallel to a plane, an angle between this plane and, for instance, the separator plate will change when rotating the shaft. Such a change is typically acceptable if not too large since the rail member can still hold the air filter in place. To reduce the change in inclination of the plane of the supporting surface, the rail member may be connected to the rotatable shaft via a hinged connection arranged to allow the rail member, and thus the supporting surface, to be oriented in (substantially) the same way even when rotating the actuating shaft and thereby moving the rail member and the supporting surface towards or away from the separator plate. The rail member may be oriented so that the supporting surface is kept parallel to the separator plate.

[0017] One or more of the rail members may comprise two (or more) sub-members arranged in a row where each sub-member contributes with a part of the total length of the supporting surface. A purpose of using such sub-members is that a common size of rail members may be used both for smaller air filters in a smaller air filtering device where shorter rail members are needed (corresponding to one sub-member) as well as for larger filters in larger devices where longer rail members are needed (corresponding to two, or more, sub-members arranged in a row). Thereby, a fewer number of unique components (rail members with different lengths) are needed.

[0018] In an embodiment, the clean compartment is located above the unclean compartment.

[0019] In an embodiment, the device is provided with a second filter aperture located further away than the first filter aperture in relation to a door side of the housing at which door side the air filters are to be introduced into and taken out from the housing when exchanged, wherein the mounting arrangement comprises third and fourth moveable rail members that extend along opposite sides of the second filter aperture and that are arranged in a way corresponding to that of the first and second rail members.

[0020] That is, the first filter aperture forms an outer aperture located relatively close to the door side and the second filter aperture forms an inner aperture located further away from the door side. In addition, a pair of rail members are positioned also at the second filter aperture and this pair is arranged in a similar way as the pair of rail members positioned at the first filter aperture.

[0021] In an embodiment, both the first and second rail members as well as the third and fourth rail members extend in parallel along opposite sides of their corresponding filter aperture, wherein the first and third rail member are aligned with each other and the second and fourth rail member are aligned with each other, and wherein all of said rail members extend in a direction towards / away from the door side of the air filtering device.

[0022] This means that when an air filter is positioned with its flanges onto the first and second rail members and is pushed and slided along these rail members in a direction away from the door side towards the second filter aperture, it is aligned with the third and fourth rail members and may be pushed further onto the third and fourth rail members and be aligned with the second filter aperture without changing its direction of movement. Thus, if the inner and outer pair of rail members are located sufficiently close together in relation a side length of the filter end structure, an filter can be suspended on the outer pair of rail members (at the first / outer filter aperture) close to the door side of the housing and simply be pushed or slided in a straight path to the inner pair of rail members (at the second / inner filter aperture).

[0023] In an embodiment, a pair of stationary rail members are arranged between the first and second filter apertures, wherein the stationary rail members are aligned with the first and third rail member and with the second and fourth rail member, respectively, and wherein upwardly directed supporting surfaces of the stationary rail members are vertically aligned with either the supporting surfaces of the first, second, third and fourth rail members when set in the first, lower position, and / or with a lower side of the filter end structure of the first air filter when the rail members are set in the first, lower position. When the movable rail members are set in their lower position, this allows a suspended air filter to be pushed / slided all the way in its path along the rail members from close to the door side to the second (inner) filter aperture even if there is a relatively large gap between the first and third (and second and fourth) rail members in the path, i.e. a gap that is at least partly filled by the stationary rail members. A further pair of stationary rail members may be arranged between the first (outer) filter aperture and the door side to extend the system of rail members to a position close to the door side and thus simplify mounting and demounting of air filters to and from the rail system.

[0024] The slide path provided by the rail system is particularly advantageous when about to install air filters at both the inner and outer filter apertures. Two air filters suspended in the rail system may be connected with an elongated connection member that has a length adapted to the distance between the first and second filter apertures so that when one of the filters is aligned with its corresponding filter aperture also the other filter is aligned. By connecting the filters via such a connection member, the whole package containing the two filters and the connection member can then be pushed / slided as one common unit along the rail system until both filters are aligned simultaneously with the corresponding filter aperture. This procedure is also described further below.

[0025] A stop lug may be provided in the device housing at the inner end of the rail system, wherein the stop lug is positioned such as to define an inner end position for the inner air filter when the filter end structure of that filter reaches the stop lug. In this inner end position, the inner filter is aligned with the second (inner) filter aperture and, because of the connection member, also the other filter is aligned with its aperture. Such a stop lug may be used even if no connection member is used or when there is only one filter aperture (and no second aperture inside of a first aperture). The air filtering device may comprise one, two, three or even more rows of inner and outer filter apertures arranged as described above, where the rows are arranged side by side as seen from the door side of the device. Such an air filtering device is thus designed for installation of two, four, six or even more air filters. It is also possible to arrange one or more additional filter apertures in each row so that one row comprises, for instance, three filter apertures.

[0026] In an embodiment, the third and fourth rail members are connected to the same actuator system as the first and second rail members.

[0027] In an embodiment, the first and second rotatable shafts extend also along opposite sides of the second filter aperture and substantially in parallel with a corresponding rail member, wherein each of the third and fourth rail member extends through the second filter aperture and is connected to a corresponding rotatable shaft so that rotation of a shaft leads to a rotation of the corresponding rail members at both the first and second filter apertures, wherein the rotation forces the supporting surface of the connected rail members to move towards or away from the separator plate.

[0028] In an embodiment, the first filter aperture has a rectangular shape. A straight side of the filter aperture simplifies the connection between a straight rail member located in the unclean compartment and, for instance, a straight rotatable shaft located in the clean compartment where the connection extends through the filter aperture. The air filter to be used is preferably provided with a rectangular filter end structure that is slightly larger than the filter aperture. Where the device is provided with more than one filter aperture, all apertures may have a rectangular shape and have the same dimensions.

[0029] The invention also concerns an air filter for an air filtering device configured to remove dust, dry particles and similar from a flow of air, said air filter comprising: a filter element configured to allow through-flow of air and to prevent through-flow of dust, dry particles and similar; and a filter end structure connected to the filter element.

[0030] The filter end structure is arranged to be detachably attached to the air filtering device, wherein the filter end structure has an outer side that faces away from the filter element, wherein the filter end structure is provided with a filter outlet opening that allows air that has flown into the air filter through the filter element to exit the air filter through the filter end structure.

[0031] The outer side of the filter end structure is provided with first and second flanges that extend on opposite sides of the filter outlet opening, wherein each of the first and second flanges extend outwardly from the outer side of the filter end structure and sideways in a direction away from the filter outlet opening so as to form an elongated contact surface that is located at a distance above the outer side of the filter top structure and that is directed downwards towards the outer side of the filter end structure, and wherein the flanges exhibit a sufficient strength to hold the air filter in place when installed in the air filtering device with the contact surface of each flange arranged onto a corresponding supporting surface arranged in the air filtering device.

[0032] The air filter may be fixed to the air filtering device in different ways. An example is that the supporting surfaces in the air filtering device are movable so that the outer side of the filter end structure can be pressed against a component of the air filtering device, such as a separator plate. A sealing may be arranged between the outer side of the filter end structure and the component it is pressed against. Another example is that some other component is arranged around the flanges and the filter outlet opening that fixes and seals the air filter. In a typical example the filter element comprises an elongated filter body with circular cross section and an end cap provided at one end thereof, and the filter end structure is arranged at the other end of the filter body.

[0033] The air filtering device may be arranged so that the air filter(s) to be installed therein is / are to be oriented vertically with the filter end structure forming a filter top structure. That means typically that both the flange contact surfaces and the corresponding supporting surfaces of the air filtering device extend in a horizontal plane with the flange contact surfaces facing downwards and the corresponding supporting surfaces facing upwards. The air filter may then be suspended in a vertical direction with the contact surface of each flange arranged onto a corresponding supporting surface, where the flanges carry the air filter. When set in this position, the air filter may be slidably moved along the supporting surfaces, e.g. for aligning the air filter with a filter aperture in the air filtering device. Such a sliding movement of the air filter is simplified if the first and second flanges extend in parallel on opposite sides of the filter outlet opening and if the pair of supporting surfaces in the air filtering device also extend in parallel.

[0034] In an embodiment, there is a distance between each of the first and second flanges and an outer perimeter of the outer side of the filter end structure so that a portion of the outer side circumferentially surrounds the first and second flanges and the filter outlet opening.

[0035] This allows the first and second flanges to project through a filter aperture in the air filtering device but still allows the outer portion of the outer side of the filter end structure to be pressed against the material that surrounds the filter aperture, such as a plate that separates a clean and an unclean compartment in a housing of the air filtering device. The dimensions of the filter aperture should of course be adapted to the dimensions of the filter end structure of the air filter to be used. In an embodiment, the filter end structure is provided with a recess adapted for snap-on connection with an elongated air filter connection member, wherein the recess is located on a side portion of the filter end structure so as receive a connection member that extends in parallel to the outer side of the filter end structure.

[0036] Such a recess, and such an associated connection member, is particularly useful where the air filtering device is adapted for vertically oriented air filters and where first and second (or more) air filters are to be installed at first and second (or more) filter apertures located in a row in the air filtering device but at different distances inside the device in relation to a door side of a housing of the device at which side the air filters are introduced into and taken out from the housing when exchanged. That is, the first filter aperture forms an outer aperture located relatively close to the door side and the second filter aperture forms an inner aperture located further away from the door side. When installing new air filters they must be aligned with the corresponding filter aperture before being fixed to the air filtering device. To lean into an unclean compartment of such a device and try to align an air filter is not a pleasant job.

[0037] To get full advantage of the recess and associated connection member, the air filtering device should be provided with a rail system or similar forming a pair of supporting surfaces (i.e. the surfaces that provide support for the contact surfaces of the flanges of the filter end portion) that extend horizontally on opposite sides of the first and second filter apertures from close to the door side to a position at the far side (inner side) of the second (inner) filter aperture. The recess and associated connection member may then be used as follows: First the second air filter (i.e. the air filter to be located farthest into the device) is suspended onto the supporting surfaces relatively closely to the door side of the housing. Then, or before suspending the second / inner air filter, an inner end of the connection member is snapped in place in the recess of the second filter. After that, the first / outer filter is suspended onto the supporting surfaces and the outer end of the connection member is snapped in place in the recess of the first / outer filter so that the two filters are connected via the connection member. The length of the connection member is adapted to the air filter device to be used so that it defines a distance between the filters that corresponds to the distance between the first and second filter apertures in the air filtering device. So, when one filter is aligned with its corresponding aperture, also the other filter is aligned with its corresponding aperture. The two air filters and the connection member can now be pushed in a sliding manner along the rail system / supporting surfaces into the housing of the device as one package. When the outer air filter has been aligned with its corresponding outer filter aperture, it can be concluded that also the inner air filter is aligned and the positioning of the air filters is finished without having to lean into the device housing.

[0038] In an embodiment, the recess is open at a lower side of the filter end structure so as to allow release of the connection member by forcing the connection member to extend in a direction that is not in parallel to the outer side of the filter end structure.

[0039] For instance, if the two air filters and the connection member are suspended vertically onto the support surfaces as one package with the connection member extending horizontally as described above, the outer air filter may be disconnected from the connection member by moving the lower part of the air filter towards the door side and thus setting the entire air filter in an angle that deviates from the vertical direction, which means that the outer side of the filter end structure is set in a plane that deviates from the horizontal plane. The outer air filter may then be taken out from the device housing without having to simultaneously handle also the connected inner air filter, which would lead to more complex manoeuvre. In an embodiment, a gasket is arranged on the outer side of the filter end structure, wherein the gasket is in the form of a closed loop that is located circumferentially outside of the filter outlet opening and of the first and second flanges.

[0040] In an embodiment, the filter element has an elongated shape, such as a tubular shape, and the filter end structure is located at one end of the filter element.

[0041] In an embodiment, the filter end section has a rectangular shape.

[0042] The filter element typically comprises a corrugated filtering material made of e.g. polyester and / or cellulose, an end cap and a supporting cage arranged on the inside of the filtering material. Such filter elements are well known as such. The filter end section may be made out of a polymeric material, such as polyamide.

[0043] The invention also concerns a method for installing an inner and an outer air filter of the above type in an air filtering device of the above type, the method comprising:

[0044] - arranging the inner and outer air filters with the recesses facing each other and with each contact surface of the flanges facing downwards and being placed onto corresponding supporting surfaces of the mounting arrangement;

[0045] - connecting the inner and outer air filters by fixing an elongated connection member into the recesses; and

[0046] - moving the connected inner and outer air filters along the support surfaces so as to align the air filters with the filter apertures.

[0047] The steps of arranging the filters onto the supporting surfaces and connecting the connection member may be carried out in different ways. Typically, the connection member is connected to the inner air filter before it is arranged onto the supporting surfaces, and then the outer filter is arranged on the supporting surfaces followed by connecting the connection member also to the outer filter.

[0048] In a further embodiment of the air filtering device, the housing comprises at least a first and a second substantially flat housing plate arranged side by side in the same plane and being connected to each other along adjacent outer portions. Each of the first and second housing plates is formed into an L-shape at its outer portion so that an edge portion of each housing plate is directed perpendicular to a main portion of the housing plate, wherein the outer portions extend along each other with the edge portions protruding in the same direction. A sealing member is arranged along a common outermost edge of the protruding edge portions and a sealing plate that partly or fully surrounds the protruding edge portions and the sealing member is arranged along the protruding edge portions. The sealing plate is attached to the first and second housing plates along the protruding edge portions so as to press the sealing member onto the outermost edge of the protruding edge portions.

[0049] Sealing of the housing is important since leakage leads to decreased cleaning efficiency and / or decreased energy efficiency of the air filtering device. Leakage also leads to pollution of dust around the device. The above housing structure provides for producing the housing by bending plates to form the protruding end portions (flanges) and to form the sealing plate and then assemble the housing by screwing the housing plates together along the flanges and screwing the sealing plate to the housing plates. Such a process is less time-consuming and more cost-efficient than welding plates together. Moreover, the sealing may be arranged by using e.g. a sealing strip made of rubber that is placed along the outermost edge of adjacent edge portions. To use such sealing strips is less complicated than using sealing foam, paste or similar sealing compounds. A (self-adhering) sealing strip may be attached to an inner wall of the sealing plate intended to press against the outermost edge of adjacent edge portions. Sealing between the two housing plates will then be provided in an efficient manner when fastening the sealing plate to the housing plates. The above structure and procedure for connecting the housing plates is well adapted for module-based air filtering devices.

[0050] In an embodiment, the first and second housing plates are fastened to each other by a first set of screws arranged in the edge portions. Screw holes in the edge portion / flange of each housing plate may be positioned so as to be aligned when the two housing plates are properly positioned in relation to each other.

[0051] In an embodiment, the sealing plate is fastened to the first and second housing plates by a second set of screws. For this purpose, corresponding screw holes may be arranged in the housing plate, typically relatively close to the protruding edge portion, as well as in the sealing plate. These screws may be fastened from a backside / inside of the housing plate to allow fastening to a flange of the sealing plate that is not accessible from the front side / outside of the housing plate. As further described below, screw holes for fastening to the housing plates may alternatively be arranged by providing cut-outs in an intermediate plate positioned between the protruding edges of adjacent housing plates.

[0052] In an embodiment, the sealing member is attached to an inner wall of the sealing plate. That is, the sealing member is properly positioned in relation to the sealing plate and will be properly positioned in relation to the slit between the protruding edge portions of the housing plates when fastening the sealing plate.

[0053] In an embodiment, the edge portions of the first and second housing plates are arranged in direct contact with each other. This option may be used for housing plate joints that run perpendicular to the plane of the separator plate. In an embodiment, the edge portions of the first and second housing plates are arranged in indirect contact with each other via an intermediate plate member. In a variant, the intermediate plate member is the separator plate. A sealing must somehow be provided between the separator plate and the housing. In this variant, an edge of the separator plate is included in the sealed connection of the housing plates. A similar structure can be used also, or alternatively, for a housing end plate, such as a top plate or a bottom plate.

[0054] In an embodiment, the intermediate plate is provided with cut-outs distributed along its edge so as to form holes for screws between the edge portions of the first and second housing plates for fastening of the sealing plate to the housing plates. Outwardly directed screw holes are thus defined by the sides of the cut-out and the housing plate edge portions that surround the cut-out on opposite sides. Corresponding screw holes aligned with the cut-outs are arranged in the sealing plate. The cut-outs can relatively easy be made in the separator plate by e.g. punching).

[0055] In an embodiment where the clean compartment is located above the unclean compartment, the air inlet comprises: an outer air inlet opening arranged on a side wall of the clean compartment; an inner air inlet opening provided in the separator plate, and an air guiding channel located in the clean compartment. The air guiding channel connects the outer and inner air inlet openings and extends through the clean compartment in a curved manner so as to direct an incoming air flow downwards towards the unclean compartment and force incoming air to enter the unclean compartment in a downwards direction.

[0056] Unclean air that enters the outer air inlet opening in a horizontal direction is thus forced to turn downwards and enter the unclean compartment from the top thereof while flowing in a downwards direction. The air guiding channel thus creates a down-flow in the unclean compartment. The down-flow forces a significant portion of dust particles present in the unclean compartment to accumulate at the bottom of the unclean compartment, and further to accumulate in a dust collector arranged below the unclean compartment, instead of whirl round or stick to the air filters, which is often the case when the incoming unclean air enters the unclean compartment from the side or from below. The down-flow is particularly advantageous when the device is provided with a pneumatic system arranged in the clean compartment and being capable of generating pulses of pressurized air into the air filters for the purpose of cleaning the air filters by blowing off particles that have adhered to filtering material at an outside of the filters. When such a pulse is generated, large amounts of dust particles are released from the filtering material. If the air filtering device is not in operation, these released dust particles may fall to the bottom of the unclean compartment as desired. However, when the pressure pulse is generated and the air filtering device is in operation, most dust particles will simply return to the filtering material if the incoming flow of unclean air enters the unclean compartment from the side or bottom. The down-flow created in the device according to this disclosure prevents to a large extent the dust particles from returning to the filtering material since the air flow forces the particles downwards.

[0057] Locating the outer air inlet opening on the side wall of the housing, instead of locating it on an upper side of the housing, has the advantage that a further filter module (if a further cleaning / filtration stage is desired) and / or a fan module may be arranged on top of the clean compartment without having to make any special adaptations to the outer air inlet opening.

[0058] In an embodiment, an air distribution plate is arranged in the unclean compartment below the inner air inlet opening, wherein the air distribution plate is provided with a plurality of openings allowing through flow of air and wherein the air distribution plate has a curved cross section with a concave side facing the inner air inlet opening. The air distribution plate spreads the downwardly directed flow of incoming air sideways so that it becomes laterally distributed but still generally directed downwards in the unclean compartment. This means that a down-flow can be created in various parts of the unclean compartment and not just below the inner air inlet opening. The curved (concave) shape of the air distribution plate distributes the air better sideways, and creates less air streams directed upwards, than a flat air distribution plate.

[0059] In an embodiment, the air guiding channel is provided with a plurality of air deflecting plates that define a plurality of separated curved air flow paths through the air guiding channel, wherein the separated curved air flow paths are arranged on top of each other as seen from the outer air inlet opening.

[0060] When the separator plate is horizontal and the outer air inlet opening is arranged in a vertical wall, each separated curved air flow path will typically define a curved 90° turn (from horizontal flow to downward flow). A first flow path located on top of a second flow path as seen from the outer air inlet opening will form a path that is longer and that has a larger radius than the second flow path (since the first flow path forms an outer curve and the second flow path an inner curve). The air deflecting plates may thus be arranged so that a radius of a first curved air flow path is larger than that of a second air flow path.

[0061] An effect of arranging air deflecting plates according to above is that flow of incoming air can be more evenly distributed in the air guiding channel and thereby also more evenly distributed when exiting the inner air inlet opening and entering the unclean compartment. In the absence of such air deflecting plates, the mass flow rate of the incoming air is more likely to be unevenly distributed when entering the unclean compartment, which may lead to a less efficient down-flow. The exact design of the air deflecting plates may depend on the particular geometry of the air guiding channel and the unclean compartment, the intended mass flow rate of incoming air, etc. BRIEF DESCRIPTION OF DRAWINGS

[0062] In the description of the invention given below reference is made to the following figure, in which:

[0063] Figure 1 a shows a perspective view of an example embodiment of an air filtering device.

[0064] Figure 1 b shows another perspective view of the embodiment of figure 1 .

[0065] Figure 1 c shows a view similar to figure 1 a but without a housing door and an upper fan module.

[0066] Figure 2 shows an example of an air filter for use in the exemplified air filtering device.

[0067] Figure 3 shows a top view of a filter end structure of the air filter of figure 2.

[0068] Figure 4 shows a side view of the filter end structure of figure 3.

[0069] Figure 5 shows a lower side of the filter end structure of figure 3 and an elongated air filter connection member.

[0070] Figures 6a and 6b show how two air filters are connected by means of the elongated air filter connection member.

[0071] Figures 7a and 7b show how two air filters are installed in the air filtering device.

[0072] Figures 8a-8d show a filter mounting arrangement of the air filtering device and how the air filter is mounted thereto.

[0073] Figure 9 shows a view from below of four air filters installed in the air filtering device.

[0074] Figure 10 shows how adjacent housing plates are connected and sealed.

[0075] Figures 11a and 11 b show details of a first variant of the housing plate connection.

[0076] Figures 12a-12d show details of a second variant of the housing plate connection.

[0077] Figure 13 shows a side view of the air filtering device with the near side housing side wall removed.

[0078] Figure 14 shows an alternative design of a movable rail member and its connection to a rotatable shaft. DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

[0079] Figures 1-13 show an air filter device 1 and replaceable air filters 100, 200, 300, 400 for use in such device. Figures 2-6 focus on the air filters and figures 7-8 focus on the procedure for installing the filters in the device. Remaining figures show various aspects of the air filtering device 1.

[0080] The exemplified air filtering device 1 is configured to be provided with four air filters 100, 200, 300, 400 and comprises in general a housing 2, a separator plate 3 that separates an interior of the housing into an unclean side with an unclean compartment 4 and a clean side with a clean compartment 5, four rectangular filter apertures (of which a first and a second are denoted 6 and 16 in the figures, respectively) in the separator plate 3 allowing air to flow from the unclean compartment 4 into the clean compartment 5 through the corresponding air filter.

[0081] The device 1 further comprises a mounting arrangement configured for mounting of the air filters 100, 200, 300, 400 at the corresponding filter aperture 6, 16 at the unclean side of the separator plate 3. An air inlet 8A, 81 , 8B for uncleaned air is arranged in fluid communication with the unclean compartment 4 and an air outlet 9 for clean air arranged in fluid communication with the clean compartment 5.

[0082] The air filtering device 1 is vertically arranged with the clean compartment 5 located on top of the unclean compartment 4 and with the separator plate 3 extending horizontally.

[0083] As shown in figures 1a and 1 b, a fan module 31 is arranged on top of the clean compartment 5. The fan module 31 comprises e.g. a fan motor 32 that, together with other parts of the fan that are not shown, generates a suction force and provides the incoming flow of unclean air to the device 1. In an alternative variant a further filtering module may be placed on top of the clean compartment with the fan module placed on top of the further filtering module.

[0084] A dust collector 33 is placed at the bottom of the unclean compartment 4. Figure 1c shows that a pneumatic system 34 for generation of pulses of pressurized air may be provided in the clean compartment 5. Such a system is used to release dust particles from the air filters so the particles can fall down and (via a hopper) accumulate in the dust collector 33. This is further described below in relation to the air inlet.

[0085] As shown in figures 7-8, the mounting arrangement comprises first and second moveable rail members 10, 11 that extend along opposite sides of the first filter aperture 6. Each of the first and second rail members 10, 11 exhibits a supporting surface 10A, 11A directed towards the clean compartment 5 and each supporting surface 10A, 11A forms a support for a corresponding flange 101 , 102 arranged on an outer side 103 of a filter end structure 104 of the first air filter 100 (see figures 2-6).

[0086] A similar rail arrangement is provided also at the three other filter apertures. As can be seen in the figures and as further described below, the mounting arrangements at the first and second filter apertures 6, 16 are interconnected so as to handle first and second air filters 100, 200 simultaneously. The mounting arrangements at the two other filter apertures are interconnected in a similar way. The device 1 may comprise only or more than two such sets of interconnected mounting arrangement. The special mounting arrangement at, for instance, the first filter aperture 6 is useful also for a single air filter without interconnection to any other mounting arrangement.

[0087] As best seen in figures 8a-8d, the first and second rail members 10, 11 are connected to an actuator system 12, 13, 14 located in the clean compartment 5 of the housing 2. The actuator system comprises first and second rotatable shafts 12, 13 extending along opposite sides of the first filter aperture 6 and substantially in parallel with a corresponding rail member 10, 11. Each rail member 10, 11 is in the form of an elongated folded plate that extends “sideways” through the filter aperture 6 and is connected to a corresponding rotatable shaft 12, 13 located in the clean compartment 5. Rotation of a shaft leads to a rotation of the corresponding rail member 10, 11 that in turn forces the supporting surface 10A, 11A to move towards or away from the separator plate 3 depending on the direction of the rotation. The actuator mechanism 14 is in this example arranged such when turning the lever, the shafts 12, 13 are simultaneously rotated at the same speed in different directions (figures 8a and 8d). Alternatively, the shafts 12, 13 may be rotated individually and / or be rotated by means of an electric motor, a pneumatic system or other driving source.

[0088] The actuator system 12, 13, 14 is configured to, by rotating the shafts 12, 13, set the first and second rail members 10, 11 in: i) a first position (see figures 8a and 8b) where the supporting surfaces 10A, 11 A are located at a distance away from the separator plate 3 at the unclean side thereof so as to allow positioning the first air filter 100 in relation to the first filter aperture 6 in the separator plate 3 by moving / sliding the first air filter 100 and its flanges 101 , 102 along the supporting surfaces 10A, 11A (see e.g. figure 7b); and ii) a second position (see figures 8c and 8d) where the supporting surfaces 10A, 11A are located closer to the separator plate 3 than in the first position, and in this case also located partly at the clean side 5 of the separator plate 3, so as to press the outer side 103 of the filter end structure 104, in this case a gasket 115, against the lower side of the separator plate 3 around the first filter aperture 6.

[0089] When set in the second position, the shafts 12, 13 are rotationally locked and the air filter 100 is set in its operational position with the gasket 115 sealing around the filter aperture 6. As already noted above, the device 1 is provided with a second filter aperture 16 located further away than the first filter aperture 6 in relation to a door side 2A (see figure 1a) of the housing 2 at which door side 2A the air filters 100, 200, 300, 400 are to be introduced into and taken out from the housing 2 when exchanged.

[0090] The mounting arrangement comprises third and fourth moveable rail members 20, 21 that extend along opposite sides of the second filter aperture 16 and that are arranged in a way corresponding to that of the first and second rail members 10, 11. Both the first and second rail members 10, 11 as well as the third and fourth rail members 20, 21 extend in parallel along opposite sides of their corresponding filter aperture 6, 16, wherein the first and third rail members 10, 20 are aligned with each other and the second and fourth rail members 11 , 21 are aligned with each other, and wherein all of said rail members extend in a direction towards / away from the door side 2A of the air filtering device 1 .

[0091] As shown in e.g. figure 7b, a pair of stationary rail members 17, 18 are arranged between the first and second filter apertures 6, 16. The stationary rail members 17, 18 are aligned with the first and third rail members 10, 20 and with the second and fourth rail members 11 , 21 , respectively. Upwardly directed supporting surfaces 17A, 18A of the stationary rail members 17, 18 are vertically aligned with a lower side 105 of the filter end structure 104 of the air filter 100, 200 when the rail members are set in the first, lower position (see figures 8b and 8d). A further pair of stationary rail members is in this case provided between the first filter aperture 6 and the door side 2A (see figures 7b and 9.

[0092] An air filter, or two connected air filters as described below, may thus be suspended on the stationary and movable rail members and be slided along the rail members into the housing 2 away from the door side 2A, see figure 7b.

[0093] As shown in e.g. figure 7a, the third and fourth rail members 20, 21 are connected to the same actuator system 12, 13, 14 as the first and second rail members. The first and second rotatable shafts 12, 13 extend also along opposite sides of the second filter aperture 16 and, similar to the arrangement of the first and second movable rail members 10, 11 , each of the third and fourth rail member 20, 21 extends through the second filter aperture 16 and is connected to a corresponding rotatable shaft. Rotation of a shaft thus leads to a rotation of the corresponding rail members at both the first and second filter apertures 6, 16.

[0094] As shown in figures 2-6, each of the air filters 100, 200, 300, 400 (exemplified by the first air filter 100 in figures 2-5) comprises: a filter element 107 configured to allow through-flow of air and to prevent through-flow of dust, dry particles and similar; and a filter end structure 104 connected to the filter element 107, where the filter end structure 104 has a rectangular shape and forms the part arranged to be detachably attached to the air filtering device 1 . The filter element 107 has in this case a conventional elongated tubular shape and the filter end structure 104 is located at one end of the filter element 107.

[0095] The filter end structure 104 has an outer side 103 that faces away from the filter element 107 and it is provided with a filter outlet opening 108 that allows air that has flown into the air filter through the filter element to exit the air filter 100 through the filter end structure 104. The outer side 103 of the filter end structure 104 is provided with first and second flanges 101 , 102 that extend on opposite sides of the filter outlet opening 108. Each of the first and second flanges 101 , 102 extend outwardly from the outer side 103 and sideways in a direction away from the filter outlet opening 108 so as to form an elongated contact surface 101 A, 102A that is located at a distance above the outer side 103 and that is directed downwards towards the outer side 103 of the filter end structure 104. The flanges 101 , 102 exhibit a sufficient strength to hold the air filter 100 in place when installed in the air filtering device 1 with the contact surface 101 A, 102A of each flange 101 , 102 arranged onto the supporting surfaces of the rail members as described above.

[0096] As indicated in figure 3, there is a distance between each of the first and second flanges 101 , 102 and an outer perimeter of the outer side 103 of the filter end structure 104 so that a portion 103A of the outer side 103 circumferentially surrounds the first and second flanges and the filter outlet opening 108. This outer portion 103A is pressed against the separator plate 3 when the air filter 100 is mounted in its operational position in the air filtering device. As shown in figure 3, a gasket 115 in the form of a closed loop is arranged in this outer portion 103A to provide a seal when the air filter 100 is mounted in its operational position. Alternatively, or as a complement, a sealing member may be attached to the separator plate 3 around the filter aperture 6 so as to be pressed onto by the outer portion 103A of the outer side 103 of the filter end structure 104.

[0097] Figures 4-7 show that the filter end structure 104 is provided with a recess 110 adapted for snap-on connection with an elongated air filter connection member 111. The recess is located on a side portion 112 of the filter end structure 104 so as receive a connection member 111 that extends in parallel to the outer side 103 of the filter end structure 104. The recess 110 is open at a lower side 105 of the filter end structure 104 (see e.g. the magnified view in figure 5) so as to allow release of the connection member 111 by forcing the connection member to extend in a direction that is not in parallel to the outer side 103 of the filter end structure 104.

[0098] The recess 110 and the connection member 111 are useful when installing (and removing), for instance, first and second air filters 100, 200 at the first and second filter apertures 6, 16 as indicated in figures 6-7. With the notations used here the second air filter 200 forms an inner filter and the first air filter 100 forms an outer in the device 1 , where “inner” means the filter will be located further away from the door side 2A of the housing 2.

[0099] A purpose of the recess 110 and the connection member 111 is to define a given distance between two air filters connected via the same connection member 111 (which has a given length). The length of the connection member 11 is adapted to the geometry of the air filtering device 1 so that both air filters will be aligned with their corresponding filter apertures when the package of the two connected air filters has been slided / inserted an appropriate distance into the housing 2. The appropriate position is in this case defined by a stop lug 35 positioned such as to define an inner end position for the inner air filter when the filter end structure of that filter reaches the stop lug.

[0100] A further purpose of the recess 110 and the connection member 111 is that the inner filter can be moved inwards and outwards by moving the outer air filter, which dispenses with the need for an operator to lean into the unclean compartment 4 to handle the inner filter.

[0101] When removing the two connected air filters from the device 1 , the open lower side of the recess 110 provides for easy release of the outer air filter from the connection member 111 by setting the outer filter in an inclined position. That is, first the connected air filters may be slided together as far as possible towards the door side 2A and then a lower end of the outer air filter is moved towards the door side 2A so that the connection member 111 comes loose from the outer air filter.

[0102] The housing may have a height of 2-3 m and its width and depth (from the side wall 2A) may be more than 1 m. Each air filter may have a height / length of more than 1 m. The device 1 has a modular structure and its dimensions, both horizontally and vertically, depend on the type and number of modules included.

[0103] A method for installing an inner and an outer air filter in the air filtering device 1 , where the first air filter 100 forms the outer air filter and the second air filter 200 forms the inner air filter, may comprise the following steps:

[0104] 51 - arranging the first and second air filters 100, 200 with the recesses 110 facing each other and with each contact surface 101 A, 102A of the flanges 101 , 102 facing downwards and being placed onto corresponding supporting surfaces of the mounting arrangement.

[0105] The “corresponding supporting surfaces of the mounting arrangement” may be supporting surfaces on the stationary and / or the movable rail members.

[0106] 52 - connecting the first and second air filters 100, 200 by fixing an elongated connection member 111 into the recesses 110.

[0107] As indicated in figure 7b, the connection member 111 may be connected to the second air filter 200 already before positioning that air filter in the device 1. The second air filter 200 is pushed / slided a suitable distance into the housing 2 along the various rail members and then the first air filter 100 is connected to the outer end of the connection member 111 so as to set the defined distance between the two air filters and allow both air filters to be moved by pushing only the first air filter 100. Step S2 may thus form part of step S1 (the air filters may be connected before both air filters are placed onto the supporting surfaces).

[0108] 53 - moving the connected first and second air filters 100, 200 along the support surfaces so as to align the air filters with the filter apertures 6, 16. As noted above, step S3 is completed when the filter end structure 104 of the second (inner) air filter 200 reaches the stop lug 35.

[0109] Figures 10-12 show that the housing 2 comprises several pairs of first and second substantially flat housing plates 41 , 42, 43, 44 arranged side by side in the same plane and that are connected to each other along adjacent outer portions. Figure 10 shows magnified views of two types of connections: the upper view shows a first type of plate pair where the connection in this case extends vertically; the lower view shows a second type of plate pair where the connection in this case extends horizontally and where the separator plate 3 is involved. More details are shown in figures 11a-11b (first type) and 12a-12d (second type).

[0110] In general, each of the first and second housing plates 41 / 42, 43 / 44) is formed into an L-shape at its outer portion so that an edge portion 41 A, 42A, 43A, 44A)of each housing plate is directed perpendicular to a main portion of the housing plate. The outer portions extend along each other with the edge portions 41 A, 42A, 43A, 44A protruding in the same direction. A sealing member 45 is arranged along a common outermost edge of the protruding edge portions 41 A, 42A, 43A, 44A and a sealing plate 46, 47 that surrounds the protruding edge portions 41 A, 42A, 43A, 44A and the sealing member 45 is arranged along the protruding edge portions 41 A, 42A, 43A, 44A. The sealing plate 46, 47 is attached to the first and second housing plates 41 , 42, 43, 44 along the protruding edge portions 41 A, 42A, 43A, 44A so as to press the sealing member 45 onto the outermost edge of the protruding edge portions 41 A, 42A, 43A, 44A.

[0111] The first and second housing plates 41 , 42, 43, 44 are fastened to each other by a first set of screws 48 arranged in the edge portions 41 A, 42A, 43A, 44A and the sealing plate 46, 47 is fastened to the first and second housing plates 41 , 42, 43, 44 by a second set of screws 49. The sealing member 45 is a rubber sealing strip attached to an inner wall of the sealing plate 46, 47.

[0112] As shown in figures 11a-11b, the edge portions 41 A, 42A in the first pair type of first and second housing plates 41 , 42 are arranged in direct contact with each other.

[0113] As shown in figures 12a-12b, the edge portions 43A, 44A of the second pair type of first and second housing plates 43, 44 are arranged in indirect contact with each other via an intermediate plate member in the form of the separator plate 3. As shown in figures 12a, 12b and 12d, the separator plate 3 is provided with cut-outs 50 distributed along its edge so as to form holes for screws 49 between the edge portions 43A, 44A of the first and second housing plates 43, 44 for fastening of the sealing plate 47 to the housing plates.

[0114] Several figures, such as figures 1c, 7a, 9 and 13, show that the air inlet comprises: an outer air inlet opening 8A arranged on a side wall of the clean compartment 5; an inner air inlet opening 8B provided in the separator plate 3; and an air guiding channel 81 located in the clean compartment 5. The air guiding channel 81 connects the outer and inner air inlet openings 8A, 8B and extends through the clean compartment 5 in a curved manner so as to direct an incoming air flow downwards towards the unclean compartment 4 and force incoming air to enter the unclean compartment 4 in a downwards direction.

[0115] An air distribution plate 82 is arranged in the unclean compartment 4 below the inner air inlet opening 8B. The air distribution plate 82 is provided with a plurality of openings 83 allowing through flow of air and wherein the air distribution plate 82 has a curved cross section with a concave side facing the inner air inlet opening 8B. The air distribution plate 82 is hold in place by supports 87 that are attached to the separator plate 3. The supports 87 comprises plates provided with a plurality of holes.

[0116] Figure 13 shows that the air guiding channel 81 is provided with a plurality of air deflecting plates 84 that define a plurality of separated curved air flow paths 85, 86 through the air guiding channel 81 . The separated curved air flow paths 85, 86 are arranged on top of each other as seen from the outer air inlet opening 8A. This provides for an even distribution of the air flow when it enters the unclean compartment 4 at the inner air inlet opening 8B.

[0117] The air guiding channel 81 is located close to a wall (the back side) of the clean compartment 5. This leaves room for placing other components, such as the pneumatic system 34, inside the clean compartment 5.

[0118] All in all the air inlet structure described above provides for an evenly distributed down-flow of incoming air through the unclean compartment 4. That is, the incoming unclean air flows in general in a downwards direction from the separator plate 3 towards the bottom of the unclean compartment, and the air deflecting plates 84 together with the air distribution plate 82 distributes in a favourable way the down-flow laterally in the unclean compartment 4.

[0119] As already described further above, a main advantage of such a down-flow is that dust particles released from the air filters when operating the pneumatic system 34 to clean the filters while there is a flow of incoming air to the air filtering device 1 (i.e. while the device 1 is in operation) can to a large extent be forced to fall down to the bottom of the unclean compartment 4 (instead of swirling around and stick to the filter again, which is more likely if the incoming air flow instead enters the unclean compartment 4 from the side). Arranging the outer air inlet opening 8A on the side of the clean compartment 5 and thus on a side wall of the housing 2 has the advantage that the fan module 31 (or other module) can be placed on top of the housing 2.

[0120] Figure 14 shows an alternative design of a movable rail member 210 and its connection to a rotatable shaft 212. The design of figure 14 works in principle in the same way as the rail members described in relation to e.g. figures 8a- 8d. A difference compared to figures 8a-8d is that the rail member 210 comprises two sub-members 221 , 222 that are arranged in a row so as to together form one main rail member 210. A further difference is that the rail member 210 is connected to the rotatable shaft 212 via a hinged connection. The hinged connection comprises a rail-supporting shaft 215 that is arranged in parallel with the rotatable shaft 212 and that is connected to the rotatable shaft 212 via first connection elements 216. The rail member 210, i.e. the two sub-members 221 , 222, is / are hinged to the rail-supporting shaft 215 via second connection elements 218 so that the rail member 210 can be oriented in the same way when the shaft 212 is rotated and the rail member 210 is moved upwards or downwards.

[0121] The invention is not limited by the embodiments described above but can be modified in various ways within the scope of the claims. For instance, the rail members may be connected to the actuator system in different ways, including various rigid or non-rigid (e.g. hinged) connections.

[0122] Figure references

[0123] 1 - air filtering device

[0124] 2 - housing

[0125] 2A - door side of housing

[0126] 3 - separator plate

[0127] 4 - unclean compartment

[0128] 5 - clean compartment

[0129] 6 - first filter aperture

[0130] 8 - air inlet (8A - outer air inlet opening, 8B - inner air inlet opening)

[0131] 9 - air outlet

[0132] 10 - first moveable rail member

[0133] 10A - supporting surface of 10

[0134] 11 - second moveable rail member

[0135] 11 A - supporting surface of 11

[0136] 12 - first rotatable shaft

[0137] 13 - second rotatable shaft

[0138] 14 - actuator

[0139] 16 - second filter aperture

[0140] 17, 18 - stationary rail members

[0141] 17A, 18A - supporting surfaces of stationary rail members

[0142] 20 - third moveable rail member

[0143] 21 - fourth moveable rail member

[0144] 31 - fan module

[0145] 32 - fan motor

[0146] 33 - dust collector

[0147] 34 - pneumatic system for generation of pulses of pressurized air

[0148] 35 - stop lug

[0149] 41 / 42, 43 / 44 - first and second housing plates arranged side by side

[0150] 41 A, 42A, 43A, 44A - edge portion of each housing plate (outer portion of L- shape) 42B - screw hole in housing plate

[0151] 45 - sealing member

[0152] 46, 47 - sealing plate

[0153] 46A - sealing plate flange

[0154] 46B - screw hole in sealing plate flange

[0155] 47A - screw hole in sealing plate

[0156] 48 - screw for connection of housing plate edge portions

[0157] 49 - screw for connection of sealing plate 47 to housing plate edge portions

[0158] 50 - screw hole / cut-out in separator plate 3

[0159] 81 - air guiding channel

[0160] 82 - air distribution plate

[0161] 83 - openings in air distribution plate

[0162] 84 - air deflecting plates in air guiding channel

[0163] 85, 86 - separated curved air flow paths defined by air deflecting plates

[0164] 87 - supports for air distribution plate

[0165] 100 - first air filter

[0166] 200, 300, 400 - second, third and fourth air filters

[0167] 101 , 102 - first and second flanges

[0168] 101 A, 102A - elongated contact surfaces of flanges

[0169] 103 - outer side of filter end structure

[0170] 103A - outer portion of outer side

[0171] 104 - filter end structure

[0172] 105 - lower side of filter end structure

[0173] 107 - filter element

[0174] 108 - filter outlet opening

[0175] 110 - recess of filter end structure

[0176] 111 - elongated air filter connection member

[0177] 112 - side portion of filter end structure

[0178] 115 - gasket 210 - rail member (alternative example)

[0179] 212 - rotatable shaft

[0180] 221 , 222 - sub-members of rail member 210

[0181] 215 - rail-supporting shaft in hinged connection 216 - first connection elements

[0182] 218 - second connection elements

Claims

35CLAIMS1. An air filtering device (1) for removing dust, dry particles and similar from a flow of air, said device comprising:- a housing (2),- a separator plate (3) that separates an interior of the housing into an unclean side with an unclean compartment (4) and a clean side with a clean compartment (5),- at least a first filter aperture (6) in the separator plate (3) allowing air to flow from the unclean compartment (4) into the clean compartment (5),- a mounting arrangement configured to allow mounting of a first replaceable air filter (100) at the first filter aperture (6) at the unclean side of the separator plate (3) so that air flowing from the unclean compartment (4) into the clean compartment (5) via the first filter aperture (6) is forced to flow through the first air filter (100) when installed in the air filtering device (1 ),- an air inlet (8) for uncleaned air arranged in fluid communication with the unclean compartment (4), and- an air outlet (9) for clean air arranged in fluid communication with the clean compartment (5), wherein the mounting arrangement comprises first and second moveable rail members (10, 11) that extend along opposite sides of the first filter aperture (6), wherein each of the first and second rail members (10, 11) exhibits a supporting surface (10A, 11A) directed towards the clean compartment (5), wherein each supporting surface (10A, 11A) is arranged to form a support for a corresponding flange (101 , 102) arranged on an outer side (103) of a filter end structure (104) of the first air filter (100), wherein the first and second rail members (10, 11 ) are connected to an actuator system (12, 13, 14) located in the clean compartment (5) of the housing (2), wherein the actuator system (12, 13, 14) is configured to set the first and second rail members (10, 11) in:36 i) a first position where the supporting surfaces (10A, 11A) are located at a distance from the separator plate (3) at the unclean side thereof so as to allow positioning the first air filter (100) in relation to the first filter aperture (6) in the separator plate (3) by moving the first air filter (100) and its flanges (101 , 102) along the supporting surfaces (10A, 11 A); and ii) a second position where the supporting surfaces (10A, 11A) are located closer to the separator plate (3) than in the first position and / or are located at the clean side (5) of the separator plate (3) so as to, when the first air filter (100) is arranged with its corresponding flanges (101 , 102) positioned onto said supporting surfaces (10A, 11 A), press the outer side (103) of the filter end structure (104) of the first air filter (100) against the separator plate (3) around the first filter aperture (6).

2. The air filtering device according to claim 1 , wherein the actuator system comprises first and second rotatable shafts (12, 13) extending along opposite sides of the first filter aperture (6) and substantially in parallel with a corresponding rail member (10, 11 ), wherein each rail member and / or its connection to the actuator system extends through the filter aperture (6) and connects to a corresponding rotatable shaft (12, 13) so that rotation of a shaft leads to a movement of the corresponding rail member (10, 11) that forces the supporting surface (10A, 11 A) to move towards or away from the separator plate (3) depending on the direction of the rotation.

3. The air filtering device (1 ) according to claim 1 or 2, wherein the clean compartment (5) is located above the unclean compartment (4).

4. The air filtering device (1 ) according to claim 3, wherein the device (1 ) is provided with a second filter aperture (16) located further away than the first filter aperture (6) in relation to a door side (2A) of the housing (2) at which door side (2A) the air filters are to be introduced into and taken out from the housing (2) when exchanged, wherein the mounting arrangement comprises third and fourth moveable rail members (20, 21 ) that extend along oppositesides of the second filter aperture (16) and that are arranged in a way corresponding to that of the first and second rail members (10, 11 ).

5. The air filtering device (1 ) according to claim 4, wherein both the first and second rail members (10, 11 ) as well as the third and fourth rail members (20, 21) extend in parallel along opposite sides of their corresponding filter aperture (6, 16), wherein the first and third rail members (10, 20) are aligned with each other and the second and fourth rail members (11 , 21 ) are aligned with each other, and wherein all of said rail members extend in a direction towards / away from the door side (2A) of the air filtering device (1 ).

6. The air filtering device (1 ) according to claim 5, wherein a pair of stationary rail members (17, 18) are arranged between the first and second filter apertures (6, 16), wherein the stationary rail members (17, 18) are aligned with the first and third rail members (10, 20) and with the second and fourth rail members (11 , 21 ), respectively, and wherein upwardly directed supporting surfaces (17A, 18A) of the stationary rail members (17, 18) are vertically aligned with either the supporting surfaces of the first, second, third and fourth rail members (10, 11 , 20, 21) when set in the first, lower position, and / or with a lower side (105) of the filter end structure (104) of the first air filter (100) when the rail members are set in the first, lower position.

7. The air filtering device (1 ) according to any of claims 4-6, wherein the third and fourth rail members (20, 21 ) are connected to the same actuator system (12, 13, 14) as the first and second rail members.

8. The air filtering device (1 ) according to claim 2 and 7, wherein the first and second rotatable shafts (12, 13) extend also along opposite sides of the second filter aperture (16) and substantially in parallel with a corresponding rail member, wherein each of the third and fourth rail member (20, 21) extends through the second filter aperture (16) and is connected to a corresponding rotatable shaft so that rotation of a shaft leads to a rotation ofthe corresponding rail members at both the first and second filter apertures (6, 16), wherein the rotation forces the supporting surfaces of the connected rail members to move towards or away from the separator plate (3).

9. The air filtering device (1 ) according to any of the above claims, wherein the first filter aperture (6) has a rectangular shape.

10. An air filter (100) for an air filtering device (1 ) configured to remove dust, dry particles and similar from a flow of air, said air filter (100) comprising:- a filter element (107) configured to allow through-flow of air and to prevent through-flow of dust, dry particles and similar;- a filter end structure (104) connected to the filter element (107), wherein the filter end structure (104) is arranged to be detachably attached to the air filtering device (1 ), wherein the filter end structure (104) has an outer side (103) that faces away from the filter element (107), wherein the filter end structure (104) is provided with a filter outlet opening (108) that allows air that has flown into the air filter through the filter element to exit the air filter (100) through the filter end structure, wherein the outer side (103) of the filter end structure (104) is provided with first and second flanges (101 , 102) that extend on opposite sides of the filter outlet opening (108), wherein each of the first and second flanges (101 , 102) extend outwardly from the outer side (103) of the filter end structure (104) and sideways in a direction away from the filter outlet opening (108) so as to form an elongated contact surface (101 A, 102A) that is located at a distance above the outer side (103) of the filter end structure (104) and that is directed downwards towards the outer side (103) of the filter end structure (104), wherein the flanges (101 , 102) exhibit a sufficient strength to hold the air filter (100) in place when installed in the air filtering device (1 ) with the contact surface (101 A, 102A) of each flange (101 , 102) arranged onto a39 corresponding supporting surface (10A, 11A) arranged in the air filtering device (1 ).

11. The air filter (100) according to claim 10, wherein there is a distance between each of the first and second flanges (101 , 102) and an outer perimeter of the outer side (103) of the filter end structure (104) so that a portion (103A) of the outer side (103) circumferentially surrounds the first and second flanges and the filter outlet opening (108).

12. The air filter (100) according to claim 10 or 11 , wherein the filter end structure (104) is provided with a recess (110) adapted for snap-on connection with an elongated air filter connection member (111 ), wherein the recess is located on a side portion (112) of the filter end structure (104) so as receive a connection member (111 ) that extends in parallel to the outer side (103) of the filter end structure (104).

13. The air filter (100) according to claim 12, wherein the recess (110) is open at a lower side (105) of the filter end structure (104) so as to allow release of the connection member (111 ) by forcing the connection member to extend in a direction that is not in parallel to the outer side (103) of the filter end structure (104).

14. The air filter (100) according to any of claims 10-13, wherein a gasket (115) is arranged on the outer side (103) of the filter end structure (104), wherein the gasket (115) is in the form of a closed loop that is located circumferentially outside of the filter outlet opening (108) and of the first and second flanges (101 , 102).

15. The air filter (100) according to any of claims 10-14, wherein the filter element (107) has an elongated shape, such as a tubular shape, and wherein the filter end structure (104) is located at one end of the filter element (107).4016. The air filter (100) according to any of claims 10-15, wherein the filter end structure (104) has a rectangular shape.

17. A method for installing an inner and an outer air filter (100, 200), each arranged according to claim 12 in an air filtering device (1) according to claim 5, the method comprising:- arranging the inner and outer air filters (100, 200) with the recesses (110) facing each other and with each contact surface (101 A, 102A) of the flanges (101 , 102) facing downwards and being placed onto corresponding supporting surfaces (10A, 11 A) of the mounting arrangement;- connecting the inner and outer air filters (100, 200) by fixing an elongated connection member (111 ) into the recesses (110);- moving the connected inner and outer air filters (100, 200) along the support surfaces so as to align the air filters with the filter apertures (6, 16).

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