Air filtering device for filtering of air and method of maintaining an air filtering device

Abstract

The present disclosure relates to an air filtering device (1) for filtering of air and to a method of maintaining the air filtering device (1), the air filtering device (1) comprising an air moving unit (6) and a first air filter unit (7) which comprises at least one first air filter (13), which is arranged in air flow direction (4) upstream of the air moving unit (6), the at 5 least one first air filter (13) comprises electrostatically chargeable fibers (14), wherein the first air filter unit (7) is directly or indirectly movable interconnected to the air moving unit (6), such that the first air filter unit (7) is by a movement (25, 26) movable from an operating position (23) to a maintenance position (24), in which the first air filter unit (7) is positioned to enable maintenance access to the at least one first air filter (13).

Description

[0001] AIR FILTERING DEVICE FOR FILTERING OF AIR AND METHOD OF MAINTAINING AN AIR FILTERING DEVICE

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to an air filtering device for filtering air and to a method of maintaining an air filtering device. In particular, the present disclosure relates to an air filtering device for filtering air comprising an air moving unit and a first air filter unit, which is directly or indirectly movable interconnected to the air moving unit and to a method of maintaining the air filtering device by moving the first air filter unit from an operating position in an maintenance position and by replacing at least one first air filter from the first air filter unit.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Air filtering devices suitable to be arranged in a volume of air are known. The conventional air filtering devices mostly comprise an air moving unit, like a fan, which guides an air flow through at least one filter for filtering the respective air volume. After a predetermined time and in particular in dependence of the contamination degree of the filtered air the air filter needs to be replaced. The replacement is conventionally done in predetermined time intervals by respective personnel, which determines the replacement intervals according to their personal experience. The conventional result is that many times the replaced filter is not contaminated enough which would justify its replacement or the filter is contaminated too much which results in a poor cleaning of the air. The overall result is that the maintenance personnel controls and maintains the respective air filter devices more often as necessary to avoid a poor cleaning result. This further results in high maintenance costs because manually checking the different air filtering devices is labor intensive. Known air filtering devices, in particular in industrial applications, are large devices, which are positioned on the ground or on a ceiling e.g. in an industrial facility. Replacing the air filters of these devices is in particular challenging, because they are placed in remote or hostile areas of the facility or on the ceiling e.g. several meters from the floor.

[0006] In the conventional air filtering devices the replacement of a filter is a challenging task, which often requires specific skills and tools. The maintenance personnel needs e.g. to climb below the air filtering device, needs to remove screws and I or housing parts of the air filtering device, needs to remove the contaminated filter along the narrow opening and needs to put the contaminated filter on a predetermined bag e.g. arranged on a belt. This entire process is extremely labor intensive and dangerous for the maintenance personnel, in particular if the filter comprises harmful particles for the operator.

[0007] SUMMARY OF THE DISCLOSURE

[0008] It is an object of the present disclosure to provide an air filter device, in particular an air filter device for filtering of air and a method of maintaining the air filtering device. In particular, it is an object of the present disclosure to provide an air filtering device and a method of maintaining the air filtering device, which address at least some of the known disadvantages from the prior art.

[0009] According to the present disclosure, an air filtering device for filtering of air is specified. The air filtering device comprises an air moving unit and at least one first air filter unit. The air filtering device may further comprise a second or additional air filter units or further components.

[0010] The air moving unit may determine partially a outer hull of the air filtering device. In other words, the air moving unit may form at least partially the outer housing of the air filtering device. The air moving unit is configured to move air through the air filtering device. The air moving unit may comprise a fan or a blowing device, which is configured to move air from point A to point B. The air moving unit of the air filtering device forms an air stream through the air filtering device and is preferably arranged on the suction side of the air filter device, i.e. down-stream with respect to the air filtering device.

[0011] The air filtering device further comprises the first air filter unit, which usually or may determines partially the outer hull of the air filtering device. In other words, the first air filter unit preferably forms partially the outer contour or housing of the air filtering device. It is also conceivable that the first air filter unit or the further air filter units are arranged in an air filter unit housing, which forms partially the outer contour or housing of the air filtering device. The first air filter unit comprise at least one first air filter, which is arranged in air flow direction upstream of the air moving unit and which is configured to filter air during operation of the air filtering device. The first air filter may comprise electrostatically chargeable fibers, which are connected via a connecting portion to the respective first air filter and at least one of their ends is arranged loose. With respect to the air flow direction, usually a downstream end of the fibers is arranged loose, such that it can move freely in the air flow during the operation of the air filtering device. The fibers are further connected via the connecting portion of the respective first air filter. The electrostatically chargeable fibers are in particular advantageous for filtering small particles from the air, which is further increased by arranging them lose in the air stream.

[0012] The first air filter unit is directly or indirectly movable interconnected to the air moving unit, such that the first air filter unit is by a movement movable back and forth from an operating position to a maintenance position and vice-versa. In the direct interconnected variation, the first air filter unit may be immediately interconnected to the air moving unit. In the indirect interconnected variation, the first air filter unit is not immediately interconnected to the air moving unit, e.g. a second air filter unit or other units are arranged between the first air filter unit and the air moving unit. Further, the air filter unit housing may be arranged between the first air filter unit and the air moving unit.

[0013] In the operating position, the first air filter unit is positioned to enable the operation of the air filtering device, in particular in that the air stream is guided through the at least one first air filter unit and I or the additional air filter units. In the maintenance position, the first air filter unit is positioned to enable maintenance access to the at least one first air filter. The air filtering device is preferably characterized in that the entire first air filter unit is moveable from the operating position in the maintenance position, thereby enabling the advantageous access for maintenance personnel to replace the at least one first air filter. The first air filter unit forms in a variation part of the outer hull of the air filtering device, this part of the hull is therefore also moved when the first air filter unit is moved to the maintenance position. It is therefore not required to first remove some housing parts or to open some hatches or the like to arrive at the first air filter. In a further variation, the at least one or plurality of first air filter units are moveable, in particular completely, out of the air filter unit housing, thereby enabling the desired access to the air filter arranged in the at least one first air filter unit. The air filtering device according to the present disclosure enables to advantageously access the first air filter for a fast and simple replacement, in particular in hostile environments or in hanging air filtering devices. The entire first air filter unit is moved, preferably via a respective mechanism, with respect to the air moving unit such that e.g. an opening to the first air filter is made accessible. The air filtering device according to the present disclosure enables that few movements of the first air filter carrying first air filter unit provide access to the first air filter, which highly increases the maintainability of the air filtering device.

[0014] In an advantageous variation the first air filter unit is directly or indirectly pivotable interconnected via a hinge to the air moving unit. The hinge connects the first air filter unit to the air filtering device in a pivotal manner. The first air filter unit is by a pivot movement pivotable from the operating position to the maintenance position. The pivot movement may move the first air filter unit by 45°, 90° or 180° +-10% around a pivot axis thereby enabling the required maintenance access.

[0015] In a variation the first air filter unit is via a track system directly or indirectly slideably interconnected to the air moving unit. In this variation, the track system connects the first air filter unit to the air filtering device. The at least one first air filter unit is in this variation by a slide movement or transversal movement moveable from the operating position to the maintenance position. The track system comprises e.g. tracks or rails and corresponding rollers or profiles arranged at the at least one first air filter unit and the other connecting part respectively, like the air moving unit or the air filter unit housing.

[0016] In an additional variation, the movement of the first air filter unit from the operating position to the maintenance position may be a combination of a pivot and slide movement.

[0017] A particular smooth movement from the operating position to the maintenance position may be realized, when the movement is damped e.g. via springs or dampers or a spring damper system, e.g. at least one gas pressure spring. The air filtering device may be highly polluted and contaminated. A fast and uncontrolled movement from the operating position to the maintenance position may stir up the dirt and may harm thereby the operator or may further pollute the air filtering device or the environment. Damping the movement advantageously reduces the potential pollution due to the maintenance itself.

[0018] In a variation, the air filtering device comprises a drive engine, preferably an electric drive engine, which is configured to move the first air filter unit from the operating position to the maintenance position and back. The drive engine may be remotely controllable by the operator. E.g. by pushing a button (a virtual button) on an application of a smart device of the operator, the first air filter unit is moved from the operating position to the maintenance position. The movement is e.g. damped as described above. The drive engine may only release a lock, which holds the first air filter unit at the air filtering device. Releasing the lock could trigger the movement from the operating position to the maintenance position.

[0019] In a variation the at least one first air filter is via guiding rails of the first air filter unit slideably insertable to and slideably removable from the first air filter unit. In other words, guiding rails are provided in the first air filter unit, which are configured to accommodate the first air filter, when they are arranged in the first air filter unit. The first air filter may comprise respective protrusions and / or depressions, which correspond to the guiding rails. In a further variation, rollers may be arranged, which advantageously improve the slide or transversal movement. In a simple form, the guiding rails are nuts arranged in the housing of the first air filter unit and the first air filter comprises protrusions, which correspond to the nuts. The guiding rails or the guiding system are arranged such that the first air filter are advantageously insertable, removable and positioned in the first air filter unit.

[0020] In another variation, the at least one first air filter is along the main air flow direction insertable into the first air filter unit till a contact portion of the first air filter reaches a counterpart shoulder portion of the first air filter unit and the first air filter is against the main air flow direction removable out of the first air filter unit. The contact portion of the first air filter may form a stop which is configured to engage with the counterpart shoulder of the first air filter unit forming the counter-stop.

[0021] A particular advantageous replacement of the at least one first air filter is realizable when the at least one first air filter is in the maintenance position of the first air filter unit slideably insertable and slideably removable from the first air filter unit along the gravitational direction. In other words, in the maintenance position of the first air filter unit, the first air filter is replaceable by sliding them out of and into the first air filter unit along the vertical direction. Removing of the first air filter may entirely happen automatically by gravity when the first air filter are e.g. unlocked from the first air filter unit. In a further variation, the first air filter unit may be slidably removed out of the air filter unit housing, preferably in gravitational direction or perpendicular to the gravitational direction. In a next step, the air filter is removed from the air filter unit, e.g. in that the first air filter unit is turned upside down, the lock mechanism may be released and the air filter slides out of the first air filter unit due to gravity.

[0022] It is also advantageous to replace the first air filter when the at least one first air filter is in the maintenance position slideably insertable and slideably removable from the first air filter unit in a direction perpendicular with respect to the gravitational direction.

[0023] A particular advantageous filter is realizable when the electrostatically chargeable fibers are at least partially made from polypropylene. Polypropylene provides the desired electrostatic properties for capturing the particles from the air.

[0024] In a further variation, the counterpart shoulder portion of the first air filter unit forms at least a portion of the track system enabling the slide movement for moving the first air filter unit from the operation position to the maintenance position and vice versa. The counterpart shoulder portion may be a protrusion extending laterally outward from unit housing wall. The contact portion of the of the air filter may be configured to be arranged at the protrusion. Further, the protrusion may extend even further laterally outward such that it may engage with a corresponding depression or nut in the air filter unit housing for slidable inserting and removing the first air filter unit into and from the air filter unit housing. In a variation, the electrostatically chargeable fibers hang at least in the maintenance position in the first air filter unit such that the loose end of each fiber is arranged below the connecting portion with respect to the gravitational direction. In the operating position and in particular during the operation of the air filtering device, the lose end of the fibers may be arranged above the connecting portion, which respect to the gravitational direction. During the movement of the first air filter unit, the lose end of the fibers is positioned, in this variation, such that it is arranged below the connecting portion. This has the advantage that when the first air filter is removed, the particles or the dust captured in the fibers is released during the removing process.

[0025] In a variation, the fibers of the at least one first air filter extend along the main air flow direction beyond the first air filter unit in the operating position. The fibers may extend into another unit of the air filtering device in the operating position. In the maintenance position, the fibers hang out of the air filtering device and out of the first air filter unit enabling advantageous access of the first air filter.

[0026] In a further variation, the air moving unit is configured to be switched on when the first air filter unit is moved from the maintenance position to the operating position, for positioning the fibers in the air filtering device. According to this variation, the fibers are advantageously sucked into their desired position and do not get stuck between the housing of the first air filter unit and the corresponding unit when the first air filter unit is moved from the maintenance position to the operating position. This is in particular advantageous when the first air filter unit is with respect to the gravitational direction arranged below the air moving unit. In this configuration, the first air filter unit may form the bottom of the air filtering device. In other configurations, e.g. when the first air filter unit is arranged above the air moving unit and the first air filter unit may form the top of the air filtering device it could also be advantageous to switch on the air moving unit to simplify the positioning of the loose fibers. In a further advantageous variation, each of the first air filters comprises elongated la- mellas, on which the fibers are connected via the connecting portion, and two bands, which hold the lamellas together thereby forming the first air filter.

[0027] The plurality of adjacently arranged elongated lamellas provide the basis on which the fibers are connected via the connecting portion. The fibers are e.g. stitched or glued onto the lamellas. The lamellas are e.g. an elongated bar, which comprise openings, through which the fibers are guided and connected. In another embodiment, the lamellas are just a rope or a piece of fabric on which the fibers are connected. The connecting portion of the fibers is the portion, e.g. one end of the respective fiber or a middle section of the fibers, which is connected to the lamella.

[0028] Further, the first air filter may comprise two bands or bars, on which the lamellas are arranged and / or connected. The band is e.g. made out of a metal or a plastic material and forms a rigid bar on which the lamellas are connectable. One of the bands is connected to one longitudinal end of the elongated lamellas and the other one is connected to the other longitudinal end of the elongated lamellas. The lamellas are arranged next to each other with respect to their main extension direction. It is preferred that the lamellas are slightly spaced apart such that air can stream though them. Further, on both longitudinal ends of the lamellas is the respective band arranged, which connects the lamellas and holds them together and in place. The fibers may extend beyond the bands.

[0029] An advantageous positioning of the first air filter is realizable when the bands comprises a cross section profile, which corresponds at least partially with the portion of the first air filter unit, in particular which forms the guiding rails, for slideably inserting and slideably removing of the at least one first air filter. In other words, the band comprises a nut or protrusion, which is configured to engage with a corresponding portion of the first air filter unit, e.g. its outer housing. It is in particular simple and easy to insert and remove the respective first air filter according to this variation.

[0030] Further, the bands may comprise a cross section profile, which forms at least partially the contact portion of the air filter configured to contact he counterpart shoulder portion of the first air filter unit. In another embodiment, a bar or a protrusion may be arranged at the band, which forms the contact portion.

[0031] It is preferred that the first air filter unit comprises a plurality of adjacently arranged first air filters, wherein a sealing is arranged between the adjacently arranged first air filter and I or between a housing wall of the first air filter unit and the first air filters for reducing bypass flow in operation of the air filtering device. A respective sealing may also be arranged if the first air filter unit only comprises one first air filter.

[0032] In another variation, a plurality of first air filter units each comprising the first air filter are arranged adjacent in the air filter unit housing. The plurality of first air filter units arranged in parallel enables to filter a larger air flow stream and to individually remove and maintain the different first air filter units. A sealing may be arranged between the plurality of first air filter units and I or between the plurality of the air filter unit housing for reducing leakages.

[0033] In a variation, the fibers of two adjacently arranged first air filters are configured to interfere with each other during operation of the air filtering device. In other words, no barrier is arranged between fibers of two adjacently arranged first air filters. It is thereby possible that the fibers of two neighboring first air filters can overlap and interfere with each other. This is in particular advantageous because bypass stream, which might flows between the two first air filter is still filtered by the overlapping fibers. In an alternative variation, in which the plurality of first air filter units is arranged adjacent in the air filter unit housing, the fibers of two adjacently arranged first air filters are separated during operation of the air filtering device by the plurality of first air filter units, in which the first air filters are arranged. In other words, the housing walls of the first air filter units separate the fibers of the different air filters from each other.

[0034] A particular advantageous and simple removing of the at least one first air filter is realizable when the first air filter unit comprises a releasable lock mechanism. The releasable lock mechanism is configured to rigidly position the at least one first air filter within the first air filter unit in the operating position and is further configured to release the at least one first air filter in the maintenance position such that the at least one first air filter is removable from the first air filter unit. The lock mechanism comprises e.g. a hock or a rod, which engaged with the at least one first air filter to hold the first air filter in position in the operating position and during the movement from the operating position to the maintenance position. Once the first air filter unit has reached the maintenance position, the lock mechanism is released, which unlocks the at least one first air filter from the first air filter unit. Either the first air filter falls automatically out of the first air filter unit due to gravity or is manually removed from the first air filter unit. The lock mechanism ensures that the at least one first air filter is kept in place as long as required. The lock mechanism may comprise an electric motor, which automatically releases, when it receives the respective command via wire or wireless from the operator. The maintenance operator may press a button on his device and the lock mechanism releases, which triggers that the first air filter slide in gravitational direction out of the first air filter unit.

[0035] Further, the air filter unit housing may comprise a releasable lock mechanism, which is configured to rigidly position the at least one first air filter unit within the air filter unit housing and to release the first air filter unit, such that it is moveable out of the air filter unit housing. A particular contamination avoiding replacement of the first air filter is realizable when the first air filter unit comprises mounts or a bracket or a plurality of brackets, which are configured to enable to mount in the maintenance position of the first air filter unit a filter bag, in which the at least one first air filter is disposable. After the first air filter is displaced to the maintenance position, the filter bag may be arranged on the mounts or brackets. As a next step, the lock mechanism, which holds the at least one first air filter in position is unlocked and the first air filters slide into the filter bag. The operator only needs to mount the filter bag; the rest is controllable remotely, which highly reduces the risk of contaminating himself.

[0036] In a variation, the air filtering device further comprises at least one additional air filter unit comprising at least one additional air filter, arranged in air flow direction downstream with respect to the first air filter unit and configured to filter air during operation of the air filtering device. The additional air filter unit may comprise a different kind of air filter for filtering another kind of contamination from the air. The additional air filter unit may comprises at least one of: a HEPA filter, a compact filter or a bag filter.

[0037] In a preferred variation, the additional air filter unit is also movable interconnected, in particular pivotable interconnected, to the air filtering device, such that the additional air filter unit is by a movement, in particular by a pivot and / or slide movement, moveable from its operating position to its maintenance position enabling access to the at least one additional air filter. The first air filter unit may be via the hinge interconnected to the additional air filter unit. And the additional air filter unit is via a second hinge interconnected to the air moving unit. All of the features described above and hereinafter with respect to the first air filter unit may also apply mutatis mutandis to the additional air filter unit. The movement of the additional air filter unit from the operating position to the maintenance position may also move the first air filter unit attached to the additional air filter unit. It is preferred when the air filtering device comprises an air flow channel extending through the air filtering device and being configured for guiding the air through the air filtering device, and wherein the first air filter unit covers the entire air flow channel for filtering of the air flowing along the air flow channel through the first air filter unit in operation of the air filtering device. In other words, when the first air filter unit is positioned in the maintenance position, the air flow channel has an opening either in the air moving unit in the additional air filter unit or in any other unit respectively arranged between the first air filter unit and the air moving unit. This opening of the air flow channel is entirely covered by the first air filter unit when it is in its operation position. In the variation in which the plurality of first air filter units is arranged in the air filter unit housing the different first air filter units form a portion of the air flow channel. In other words, the air flow stream is separated into the plurality of first air filter units.

[0038] It is preferred that the first air filter unit forms a circumferential portion of the outer hull of the air filtering device. The first air filter unit forms e.g. the bottom or top part of the entire air filtering device and therefore a circumferential portion of the outer hull of the air filtering device. In the variation in which the plurality of first air filter units is arranged in the air filter unit housing, the air filter unit housing may form the circumferential portion of the outer hull of the air filtering device.

[0039] The air filter unit housing may comprise a hatch or a detachable or pivotable housing part providing access to the first air filter units.

[0040] It is even more preferred when the first air filter unit forms partially the outer hull of the air filtering device in all directions, besides the direction which is directed to the air moving unit when the first air filter unit is in its operation position. E.g. the air filtering device may have a box like elongated shape and the bottom is formed by the first air filter unit. In this case, each of the four sides of the outer hull of the air filtering device are partially formed by the first air filter unit and the bottom, is entirely formed by the first air filter unit, when the first air filter unit is in its operating position.

[0041] In a variation has the air filtering device a rectangular cross-section with respect to a main air flow direction, in particular the first air filter unit and further units of the air filtering device have the same rectangular cross section with respect to the main air flow direction. In other words, the first air filter unit, the second air filter unit, any additional units and the air moving unit have according to this variation the same lateral rectangular extensions, which respect to the main flow direction of the air filtering device. The main flow direction is the direction of air flow through the air filtering device, which has the longest extension with respect to other air flow directions.

[0042] In a variation, the air filtering device has a cuboid or box like shape, which is at least build up by a cuboid or box like shaped first air filter unit and a cuboid or box like shaped air moving unit and / or a cuboid or box like shaped additional air filter unit. The different units are preferably are stacked onto each other and interconnected via respective mechanisms with respect to each other.

[0043] An advantageous detection of maintenance is realizable when the air filter device comprises at least one pressure sensor, which is arranged in the air filtering device, and which is configured to provide a pressure signal, which is characteristic for the pressure of the air streaming through the air filtering device in its operation. The pressure signal is used to determine if maintenance of the air filtering device is required. Throughout the operation of the air filtering device, the pressure varies in particular in dependence of the contamination degree of the filters. The higher the contamination degree, the higher or lower the pressure signal (depending on the positioning of the pressure sensor). The pressure signal is e.g. constantly monitored and constantly compared to a threshold. When the pressure signal fulfills e.g. reaches the threshold the replacement of the filter is required. A respective alert or notification is transmitted which triggers further steps. It is not required anymore to constantly manually check the contamination degree or to check the contamination degree in predetermined time intervals, which highly reduces the maintenance costs, in particular because personnel is only sent when required.

[0044] In a further preferred variation, the first air filter unit comprises a unit housing wall, which forms at least partially a streaming channel within which the electrostatically chargeable fibers of the air filter are at least partially arranged. The unit housing wall of the first air filter unit covers preferably at least 50 % of the extension of the electrostatically chargeable fibers, more preferably 100% of the extension of the electrostatically chargeable fibers, even more preferably the unit housing wall extends beyond the electrostatically chargeable fibers, when the first air filter is arranged in the first air filter unit. Furthermore, the unit housing wall, which may comprise four wall sections, is e.g. circumferentially closed, thereby forming a closed streaming channel. The unit housing wall may further comprise reinforcing corrugations. It is thereby possible to control or increase the density of the electrostatically chargeable fibers in the first air filter unit, for improving the filtering.

[0045] In a further variation, the unit housing wall is arranged tapered along the electrostatically charged fibers. In other words, the distance from one sidewall to the diametrically opposed sidewall decreases along the air flow direction trough the first air filter unit. It is thereby ensured that the electrostatically chargeable fibers are distributed evenly across the stream channel and further it is possible to control the density of the electrostatically chargeable fibers.

[0046] In a further variation, at least one housing wall is arranged moveable, which enables to control the shape of the streaming channel and in particular the flow area. The movement of at least one housing wall may be automatically controlled and performed via a control unit and a respective drive motor. Different contamination degrees may require to change the flow area such that a constant filtering result is achievable. The signal from the pressure sensor may be used to control the moveable housing wall. Movement of the housing wall outwardly may reduce the density of the electrostatically chargeable fibers and movement of the housing wall inwardly may increase the density of the electrostatically chargeable fibers, which may determine the pressure drop across the first air filter.

[0047] According to a further aspect of the present disclosure a method of maintaining an air filtering device is specified. The method comprising the steps of:

[0048] • Providing or having an air filtering device as described above and hereinafter.

[0049] • Moving the first air filter unit form the operating position in the maintenance position. This may be performed manually or automatically via the electric motor.

[0050] • Replacing at least one of the first air filters from the first air filter unit. The replacing is done e.g. after the filter bag is arranged by unlocking the lock mechanism.

[0051] It is further preferred when the method comprises the step of determining if maintenance of the air filtering device is required, in particular by using the pressure signal from the pressure sensor. The pressure signal is e.g. constantly or in predetermined intervals compared to a preset threshold value. When the pressure signal fulfills the threshold, a respective alert or notification is sent to an operator to initiate the maintenance of the air filtering device.

[0052] It is further preferred when the method comprise the step of washing the contaminated air filter and reusing it in the same or in a different air filtering device.

[0053] It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

[0054] BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing: Fig. 1 a first perspective view of an air filtering device according to a first embodiment;

[0056] Fig. 2 a second perspective view of an air filtering device according to a second embodiment;

[0057] Fig. 3 a third perspective view of the air filtering device as shown in Figure 1 , wherein a first air filter unit is displaced in the maintenance position;

[0058] Fig. 4 a fourth perspective detail view of the air filtering device as shown in Figure 1 , indicating first air filters according to a first embodiment;

[0059] Fig. 5 a fifth perspective detail view of the air filtering device as shown in Figure 1 , indicating first air filters according to a second embodiment; Fig. 6 a sixth perspective view of the air filtering device as shown in Figure 2, wherein the first air filter unit is displaced in the maintenance position according to a first embodiment;

[0060] Fig. 7 a seventh perspective view of the air filtering device as shown in Figure 2, wherein the first air filter unit is displaced in the maintenance position according to a second embodiment;

[0061] Fig. 8 a first perspective view of the first air filter unit according to a first embodiment;

[0062] Fig. 9 a second perspective view of the first air filter unit according to a second embodiment;

[0063] Fig. 10 a third perspective view of the first air filter unit according to a third embodiment;

[0064] Fig. 11 a first perspective view of a first air filter according to a first embodiment;

[0065] Fig. 12 a second perspective view of a first air filter according to a second embodiment;

[0066] Fig. 13 an eight perspective view of the air filtering device as shown in Figure 2, wherein the first air filter unit is displaced in the maintenance position according to the second embodiment and a filter bag is arranged on the first air filter unit;

[0067] Fig. 14 a flow chart showing a sequence of steps of a method of maintaining an air filtering device Fig. 15 a perspective view of the first air filter unit according to a fourth embodiment arranged in an air filter unit housing;

[0068] Fig. 16 a perspective view of the first air filter unit according to the fourth embodiment of Figure 15 showing advantageously the plurality of the first air filter units arrangeable in the air filter unit housing;

[0069] Fig. 17 a perspective view of the air filter unit housing of the Figures 15 and 16;

[0070] Fig. 18 a perspective view of the first air filter unit according to the fourth embodiment;

[0071] Fig. 19 a perspective view of the air filter unit housing accommodating three first air filter units according to the fourth embodiment.

[0072] DETAILED DESCRIPTION OF THE DRAWINGS

[0073] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0074] Figure 1 shows a first perspective view of an air filtering device 1 according to a first embodiment. Figure 2 shows a second perspective view of an air filtering device 1 according to a second embodiment. Figure 3 shows a third perspective view of the air filtering device 1 as shown in Figure 1 , wherein a first air filter unit 7 is moved in the maintenance position 24. Figure 4 shows a fourth perspective detail view of the air filtering device 1 as shown in Figure 1 , indicating first air filters 13 according to a first embodiment. Figure 5 a fifth perspective detail view of the air filtering device 1 as shown in Figure 1 , indicating first air filters 13 according to a second embodiment Figure 6 shows a sixth perspective view of the air filtering device 1 as shown in Figure 2, wherein the first air filter unit 7 is displaced in the maintenance position 24 according to a first embodiment. Figure 7 a seventh perspective view of the air filtering device 1 as shown in Figure 2, wherein the first air filter unit 7 is displaced in the maintenance position 24 according to a second embodiment. Figure 8 shows a first perspective view of the first air filter unit 7 according to a first embodiment. Figure 9 shows a second perspective view of the first air filter unit 7 according to a second embodiment. Figure 10 shows a third perspective view of the first air filter unit according to a third embodiment. Figure 11 shows a first perspective view of a first air filter 13 according to a first embodiment. Figure 12 shows a second perspective view of a first air filter 13 according to a second embodiment. Figure 13 shows an eight perspective view of the air filtering device 1 as shown in Figure 2, wherein the first air filter unit 7 is displaced in the maintenance position 24 according to the second embodiment and a filter bag 22 is arranged on the first air filter unit 7. Figure 14 shows a flow chart showing a sequence of steps of a method of maintaining the air filtering device 1. Figure 15 shows a perspective view of the first air filter unit 7 according to a fourth embodiment arranged in an air filter unit housing 35. Figure 16 shows a perspective view of the first air filter unit 7 according to the fourth embodiment of Figure 15 showing advantageously the plurality of the first air filter units 7 arrangeable in the air filter unit housing 35. Figure 17 is a perspective view of the air filter unit housing 35 of the Figures 15 and 16. Figure 18 is a perspective view of the first air filter unit according to the fourth embodiment and Figure 19 is a perspective view of the air filter unit housing accommodating three first air filter units according to the fourth embodiment. Figure 1 shows the air filtering device 1 in a perspective view. The air filtering device 1 has a cuboid or box like shape. The air filtering device 1 comprises a plurality of different units, in the present embodiment an air moving unit 6, which is configured to move air through the air filtering device 1 , a first air filter unit 7, which is configured to filter air during operation of the air filtering device 1 and two additional air filter units 12, which are arranged between the air moving unit 6 and the first air filter unit 7. The first air filter unit 7 is therefore indirectly interconnected to the air moving unit 6. The two additional air filter units 12 are also configured to filter air during operation of the air filtering device 1 , e.g. by using different kind of filters or filter technologies compared to the first air filter unit 7. Figure 1 further shows schematically the air flow through the air filtering device 1 in operation. The air inflow 2 is arranged in the first air filter unit 7. The air inflow 2 is e.g. an opening in the first air filter unit 7. The air further streams through the air filtering device 1 through the air flow channel 5 along the main air flow direction 4 passing through the first air filter unit 7, the additional air filter unit 12 and reaches the air moving unit 6, which produces the required negative pressure for the air flow. The air moving unit 6 comprises openings, which form the air outflow 3 out of the air filtering device 1 . Figure 1 further advantageously shows hinges 8, which are arranged between the first air filter unit 7 and the additional air filter units 12 and between the two additional air filter units 12 and between the additional air filter unit 12 and the air moving unit 6. The hinges 8 enable a pivot movement with respect to a pivot axis 28 between the different units. A releasable fastener 31 is e.g. arranged on one or more sides between the different units to hold them together during operation. The fastener 31 , may be automatically or manually released to enable the movement of the different units from an operating position 23, as shown in Figure 1 , to a maintenance position 24, as shown e.g. in Figure 3. The air filtering device 1 as shown in Figure 1 is e.g. arranged on a ceiling of an industrial facility for filtering the air in this facility. The air filtering device 1 may comprise attachment arrangements for chains or ropes. Figure 1 and many of the following Figures further show that the first air filter unit 7, the air moving unit 6 and / or the additional air filter units 12 form at least partially the outer hull 32 of the air filtering device 1. E.g. the first air filter unit 7 and the air moving unit 6 form the bottom or the top of the air filtering device 1 and vice versa. The additional air filtering units 12 form the middle section of the air filtering device 1 , and in particular the middle section of the outer hull 32. All the units have according to the embodiments of the Figures a box like shape and are stacked onto each other forming the cuboid shape of the air filtering device 1. In the embodiment of the first air filter unit 7 shown in the Figures 15 to 17, the first air filter units 7 do not form the outer hull of the air filtering device 1. In this embodiment is the outer hull of the air filtering device 1 formed by the air filter unit housing 35, in which the plurality of first air filter units 7 is slidable arranged.

[0075] Figure 2 shows also an air filtering device 1 according to a second embodiment. This air filtering device 1 may be configured to be placed on the floor of the industrial facility. The main air flow direction 4 follows the gravitational direction 27 and is arranged opposite with respect to the embodiment of Figure 1 . Further, the air filtering device 1 of Figure 2 differs from Figure 1 in the hinge 8. The hinge 8 enables a pivot movement 25 around the pivot axis 28, which is arranged parallel to the gravitational direction. The pivot movement 25 according to this embodiment is explained in more detail with respect to Figure 6. The air filtering device 1 also comprises a fastener 31 , which releasably interconnects the first air filter unit 7 with the additional air filter unit 12.

[0076] Figure 3 shows the air filtering device 1 according to the embodiment shown in Figure 1 , wherein the first air filter unit 7 is arranged in the maintenance position 24. Figure 3 advantageously shows the pivot movement 28 around the pivot axis 28 of the first air filter unit 7. An electric engine (not shown) may move the first air filter unit 7, after the (automatical and remote) releasing of the fastener 31 , from the operating position 23 to the maintenance position 24. The pivot movement 25 fulfills a rotation of 180° degree according to this embodiment. In other embodiment the rotation angle may be different e.g. 45°, 90°, 135° etc. Figure 3 further advantageously shows that interior of the first air filter unit 7 gets accessible by the pivot movement 25. The single pivot movement 25 enables to access the interior of the first air filter unit 7.

[0077] Figure 4 shows the air filtering device 1 of Figure 3 in a detailed view. Figure 4 in particular indicates first air filters 13, which are arranged and positioned in the first air filter unit 7. According to this embodiment, the first air filter unit 7 comprises three first air filters 13 arranged next to each other. Figure 4 further advantageously shows the replacement movement 29 of the first air filters 13. The replacement movement 27 is arranged parallel to the gravitational direction 27. In other words, the first air filters 13 are removed from the first air filter unit 7 in gravitational direction 27. New first air filters 13 may be inserted into the first air filter unit 7 in opposite direction, indicated in Figure 4. The first air filters 13 may be insertable and removable from the first air filter unit 7 along guiding rails 10 (shown e.g. in Figure 8), which are arranged in the housing of the first air filter unit 7. Further, the first air filter 13 might be locked into the first air filter unit 7 by a lock mechanism 20, which positions them into the first air filter unit 7. The lock mechanism 20 is releasable, e.g. by rotating a bar or by pushing a button, which triggers that the first air filters 13 slide out of the fist air filter unit 7, e.g due to gravity or a motor.

[0078] Figure 5 shows a similar detail embodiment as shown in Figure 4. The difference lies in that the pivot movement 25 fulfilled only a rotation of 90°. Figure 5 indicates two possible replacement movements 29 of the first air filters 13. In a first variation, the first air filters 13 are removed by the replacement movement 29 perpendicular to the gravitational direction. In a second variation, the first air filters 13 are removed by the replacement movement 29 parallel to the gravitational direction. In the second variation, a flap or a hatch arranged on the outer hull of the first air filter unit 7 might have to be released to access the first air filter 13. It is of course also conceivable that the first air filter 13 forms partially the outer hull 32 itself.

[0079] Figure 6 shows the air filtering device 1 of Figure 2, wherein the first air filter unit 7 is arranged in the maintenance position 24. The first air filter unit 7 is rotated via the hinge 8 around the pivot axis 28 by ca. 180°. Other rotation angles e.g. 90° would of course also be conceivable. Figure 6 further advantageously shows four first air filters 13 arranged in the first air filter unit 7 and further shows the replacement movement 29 of these first air filters 13 along the gravitational direction 27.

[0080] Figure 7 shows a similar embodiment to Figure 6. Figure 7 differs from Figure 6 in that the movement of the first air filter unit 7 from the operating position 23 to the maintenance position 24 is a slide movement 26 or transversal movement 26. In this embodiment, the first air filter unit 7 is connected to the respective additional air filter unit 12 via a rail or track system 9, which enables the slide movement 26. The track system 9 may comprise rails on the additional air filter unit and rollers arranged on the first air filter unit 7 or vice versa. A sealing or sealing system may be arranged to ensure air tightness between the different units in the operating position 23. The other embodiments might also comprise a respective sealing or sealing system. The rail system 9 further might comprise an engine to remotely control the movement of the first air filter unit 7. Figure 7 additionally shows the replacement movement 29 of the three first air filters 13.

[0081] Figure 8 shows an embodiment of the first air filter unit 7. The first air filter unit 7 comprises three first air filter 13, which are slideably arranged via guiding rails 10 in the first air filter unit 7. The first air filter unit 7 comprises an outer housing 30, which also comprises slots or depressions forming the guiding rails 10 for inserting and removing of the first air filters 13. The first air filters 13 on the other side comprise structures, which correspond to the guiding rails 10. The first air filters 13 are positioned in the first air filter unit 7 via the lock mechanism 20, which holds them in position as long as the lock mechanism 20 is not unlocked. The lock mechanism 20 may be controlled via an electric signal received by a drive engine preferably remotely. In another embodiment, the lock mechanism 20 may be manually unlockable. The first air filter 13 comprise a plurality of electrostatically chargeable fibers 14, which are connected by a connecting portion 16 to lamellas 17. At least one end 15 of the fibers 14 is arranged loose. The lamellas 17 are connected to two bands 18, in particular at their longitudinal end. The assembly forms the first air filter 13.

[0082] Figure 9 shows another embodiment of the first air filter unit 7. In the preceding embodiment, described above, the first air filter 13 is at least circumferentially surrounded by the housing of the first air filter unit 7. In the embodiment shown with respect to Figure 9 this is not the case. The first air filter unit 7 comprises only a small housing on which the first air filter 13 are arranged. In particular, the fibers 14 extend beyond the first air filter unit 7. In the operating position 23, the fibers 14 are arranged in the additional air filter unit 12 as indicated in Figure 9. In order to arrange all of the fibers 14 in the air filtering device 1 as desired when the first air filter unit 7 is moved back from the maintenance position 24 to the operating position 23, the air moving unit 6 might be turned on such that the fibers 14 are sucked in and are not trapped between the first air filter unit 7 and the additional air filter unit 12. Figure 9 further indicates the replacement movement perpendicular to the gravitational direction 27 for replacing the first air filter 13. It would be of course also conceivable that the replacement movement is parallel to the gravitation direction 27, in particular when the pivot movement 25 is e.g. not 180° as shown in Figure 9 but 90°.

[0083] Figure 10 shows a further embodiment of the first air filter unit 7, which is arranged at the top of the air filtering device 1 and which has a similar structure as presented with respect to Figure 9. The fibers 14 of the first air filters 13 extend at least in the operating position 23 of the first air filter unit 7 into the additional air filter unit 12 arranged below. Figure 10 further indicates possible replacement movements 29 to replace the first air filter 13.

[0084] Figure 11 shows a detailed perspective view of the first air filter 13 as presented in the Figures 9 and 10. The fist air filter 13 comprises a plurality of the electrostatically chargeable fibers 14, which are connected via the connecting portion 16 to the lamellas 17. The lamellas 17 are e.g. rigid bars, a fabric, a rope or a filament, on which the fibers 14 are connectable. At least one end 15 of the fibers 14 is arranged loose in the air flow. The first air filter 13 further comprises a band 18 or a lateral bar, which forms the basis on which the lamellas 17 are connected, in particular their longitudinal ends. The bars 18 are e.g. made out of plastic or metal material and comprise a respective profile for engaging in the guiding rails 10 of the first air filter unit 7. The bars 18 might also comprise a respective structure to receive a hook of the lock mechanism 20.

[0085] Figure 12 shows a second detailed perspective view of the first air filter 13 according to the embodiment shown in Figure 8. The embodiment of Figure 12 differs in particular from the embodiment of Figure 11 in that the lamellas 17 are made out of solid material, e.g. plastic material.

[0086] Figure 13 shows the air filtering device 1 according to Figure 7 and further shows a filter bag 22 arranged on the first air filter unit 7. The filter bag 22 is e.g. arranged on dedicated brackets 11 arranged on the first air filter unit 7, in particular on the outer side of the first air filter unit 7. Figure 13 further shows advantageously the entire process of removing contaminated first air filters 13 from the air filtering device 1 according to the present disclosure. First, it is determined that it is required to replace the contaminated first air filters 13. This is either done by a manual inspection or by using the pressure signal of the pressure sensor 21 of the air filtering device 1 . Next, the first air filter unit 7 is moved from the operating position 23 into the maintenance position 24 enabling access to the first air filter 13. The movement might be a pivot movement 25, a slide movement 26 or a combination thereof. Further, the movement is e.g. damped, manually or automatically, via an electric engine, executed. The first air filter 13 are kept in position e.g. by the lock mechanism 20 during the movement. In a next step, the filter bag 22 is positioned on the bracket 11. The lock mechanism 20 is afterwards unlocked (manually or electrically), which triggers that the first air filters 13 fall out of the first air filter unit 7 into the filter bag 22. The operator might control this step remotely such that his contamination is avoided. In the last step, the filter bag 22 is removed, new first air filters 13 are installed and the first air filter unit 7 is moved back into its operating position 23.

[0087] Figure 14 shows schematically a flow chart depicting the different steps of maintaining the air filtering device 1 as also described above with respect to Figure 13.

[0088] In a first step S1 , the air filtering device 1 as described above and hereinafter is provided or used for filtering air.

[0089] In a second step S1a, it is determined if maintenance of the air filtering device 1 is required. This might be performed via manual inspection or automatically using pressure signal from the pressure sensor 21.

[0090] In a third step S2, in case it is determined that maintenance is required, the first air filter unit 7 is moved from the operating position 23 into the maintenance position 24.

[0091] In a fourth step S3, the at least one first air filter 13 is replaced.

[0092] The method described with respect to Figure 14 might further comprise additional steps as indicated above or hereinafter, in particular with respect to the different features, providing certain functionalities, of the air filtering device 1 described above and hereinafter.

[0093] The Figures 15 to 19 show a further variation of the air filtering device 1. In this variation, the first air filter unit 7 does not form partially the outer hull 32 of the air filtering device 1. The plurality of first air filter units 7 comprising the first air filter 13 are arranged adjacent to each other in an air filter unit housing 35, which houses the first air filter units 7 and which forms the outer hull 32 of the air filtering device 1. The air filter unit housing 35 may comprise a hatch or a detachable housing portion, through which the first air filter units 7 are insertable and removable from the air filter unit housing 35, thereby connecting the first air filter units 7 directly or indirectly with the air moving unit 6. When the air filter units 7 are arranged in the air filter unit housings 35 they are in the operating position 23 and when they are moved out of the air filter unit housing 35 they are in the maintenance position 24, enabling access to the first air filters 13 arranged in the first air filter units 7. The Figures 15 to 17 show that the first air filter units 7 comprise a track system 9, which enables that the first air filter units 7 are slidably insertable into the air filtering device 1 , in particular into the air filter unit housing 35. The track system 9 comprises housing guiding rails 34 arranged in the air filter unit housing 35. The housing guiding rails 34 are for example depressions on the housing walls, along which the first air filter units 7 are insertable. The track system 9 further comprises a corresponding track counterpart arranged or formed at the first air filter units 7. In the variation shown in the Figures 15 to 19, a counterpart shoulder portion 37 extends laterally outwards from a unit housing walls 38 of the first air filter units 7. The counterpart shoulder portion 37 forms a protrusion, which is configured to engage with the housing guiding rails 34, for slidably inserting and removing of the air filter unit housing 35. Another track system 9, comprising e.g. rollers, may also be conceivable. Figure 15 further advantageously shows the first air filter 13, which is moveable into the first air filter unit 7 along the main air inflow direction 4. The first air filter unit 7 comprises an air flow inlet opening and an air flow outlet opening. The unit housing wall 38 extends between the inlet opening and the outlet opening. The unit housing wall 38 comprises preferably a plurality of sidewalls, e.g. four sidewalls forming an air flow channel portion 33. The intel opening or the upstream portion of the unit housing wall 38 further forms a holding portion or a positioning portion for positioning of the first air filter 13 in the first air filter unit 7. The holding portion is according to the variation shown in the figures the counterpart shoulder portion 37, which also forms partially the track system 9. The first air filter 13 comprises a contact portion 36, which is configured to engage with the counterpart shoulder portion 37 for positioning the first air filter 13 in the first air filter unit 7. The contact portion 36 may be a bar or a strip arranged at the band 18 of the first air filter 13. Further, the band 18 may have a cross section profile, which forms the contact portion 36. The first air filter 13 is insertable into the first air filter unit 7 till the contact portion 36 engages with the holding portion, in particular the counterpart shoulder portion 37. The shape of the contact portion 36 corresponds in particular with the shape of the counterpart shoulder portion 37, such that the first air filter 13 is advantageously placeable in the first air filter unit 7. The counterpart shoulder portion 37 forms in this variation simultaneously the holding portion and the track system 9.

[0094] The Figures 15 and 16 further advantageously show that the three first air filter units 7 are insertable adjacently, in parallel with respect to the main airflow direction 4, through an opening in the air filter unit housing 35, into the air filter unit housing 35. Each of the first air filter units 7 comprises a handle enabling to move the first air filter unit 7 into and out of the air filter unit housing 35. Further, the adjacently arranged air filter units 7 may also be connected with each other e.g. via a rope or chain such that they are removable together. In a further variation, the first air filter 7 may house a plurality of first air filters 14. In other words, the three first air filter 7 are e.g. welded or glued together or are formed out of one mold.

[0095] Figure 16 further advantageously shows that the air flow stream is separated into three parallel arranged air flow channel portions 33, which are formed by the three first air filter units 7, in particular by the three unit housing walls 38. The unit housing walls 38 are e.g. tapered towards the air outflow end 3 thereby compressing at least partially the electrostatically chargeable fibers 14 of the first air filter 13. The unit housing wall 38 may comprise corrugations, which improve the stiffness, in particular the bending stiffness, of the respective side walls 38. The improved bending stiffness is important such that the side walls 38 keep their shape even if the air stream at one side forms a negative pressure. The first air filter unit 7 are e.g. stackable into each other due to the tapered housing walls 38, thereby improving the transportability.

[0096] The lock mechanism 20 may releasably position the first air filter units 7 in the air filter unit housing 35. Further, the first air filters 13 may also be releasably locked by a locking mechanism into the first air filter units 7.

[0097] Figure 17 shows a variation of the air filter unit housing 35 in which the three first air filter units 7 are removable independently, which means that each of the first air filter units 7 is removable without removing any other. The track system 9 comprises the respective housing guiding rails 34.

[0098] Figure 18 advantageously shows the first air filter unit 7 with all its details. Figure 18 in particular show the unit housing wall 38, comprising four sidewalls, forming the air flow channel portion 33, the counterpart shoulder portion 37, which forms part of the track system 9. Figure 18 further shows the air inflow 2 along the main air flow direction 4 through the air intel opening formed by the upstream portion of the unit housing wall 38 and the air outflow 3 along the main air flow direction 4 through the air outflow opening formed by the downstream portion of the unit housing wall 38.

[0099] Figure 19 shows the air filter unit housing 35 comprising three first air filter units 7. The three first air filter units 7 are adjacently arranged next to each other, in particular they contact each other thereby reducing any bypass air flow. Further, a sealing may be arranged at the contact portion to further reduce any bypass air flow.

[0100] The Figures 15 to 19 advantageously show that the three first air filter units 7 are after a predetermined usage time comprising the contaminated first air filters 13 movable into the maintenance position 24 out of air filter unit housing 35. During the movement the dirt and the particles in the first air filters 13 are kept relatively safe due to the surrounding unit housing wall 38. In other words, the maintenance movement does not stir up the dirt and the particles, which helps to increase the safe handling and replacing of the contaminated first air filters 13.

[0101] LIST OF REFERENCE SYMBOLS

[0102] 1 Air filtering device 23 Operating position

[0103] 2 Air inflow 24 Maintenance position

[0104] 3 Air outflow 25 Pivot movement

[0105] 4 Main air flow direction 26 Slide movement

[0106] 5 Air flow channel 30 27 Gravitational direction

[0107] 6 Air moving unit 28 Pivot axis

[0108] 7 First air filter unit 29 Replacement movement

[0109] 8 Hinge 30 Housing of the first air filter

[0110] 9 T rack system unit

[0111] 10 Guiding rails 35 31 Fastener

[0112] 11 Bracket 32 Outer hull of the air filtering

[0113] 12 Additional air filter unit device

[0114] 13 First air filter 33 Air flow channel portion

[0115] 14 Electrostatically chargeable 34 Housing guiding rails fibers 40 35 Air filter unit housing

[0116] 15 Lose end of the fibers 36 Contact portion

[0117] 16 Connecting portion of the fi37 Counterpart shoulder porbers tion

[0118] 17 Lamella 38 Unit housing wall

[0119] 18 Band 45 S1 Providing

[0120] 19 Sealing S1a Determining

[0121] 20 Lock mechanism 52 Moving

[0122] 21 Pressure sensor 53 Replacing

[0123] 22 Filter bag

Claims

PATENT CLAIMS1. Air filtering device (1) for filtering of air, the air filtering device (1) comprising: a. an air moving unit (6), which is configured to move air through the air filtering device (1); b. a first air filter unit (7), which comprises at least one first air filter (13), which is configured to filter air during operation of the air filtering device (1), the at least one first air filter (13) comprises electrostatically chargeable fibers (14), which are connected via a connecting portion (16) to the respective first air filter (13) and at least one of their ends (15) is arranged loose; c. wherein the first air filter unit (7) is directly or indirectly movable interconnected to the air moving unit (6), such that the first air filter unit (7) is by a movement (25, 26) movable from an operating position (23), in which the first air filter unit (7) is positioned to enable the operation of the air filtering device (1), to a maintenance position (24), in which the first air filter unit (7) is positioned to enable maintenance access to the at least one first air filter (13).

2. The air filtering device (1) according to claim 1 , wherein the first air filter unit (7) is via a hinge (8) directly or indirectly pivotable interconnected to the air moving unit (6), such that the first air filter unit (7) is by a pivot movement (25) pivotable from the operating position (23) to the maintenance position (24) and / or wherein the first air filter unit (7) is via a track system (9) directly or indirectly slideable interconnected to the air moving unit (6), such that the first air filter unit (7) is by a slidemovement (26) moveable from the operating position (23) to the maintenance position (24).

3. The air filtering device (1) according to any one of the preceding claims, wherein the first air filter unit (7) determines partially the outer hull (32) of the air filtering device (1), or wherein the first air filter unit (7) is arranged in an air filter unit housing (35), which forms at least partially the outer hull (32) of the air filtering device (1).

4. The air filtering device (1) according to any one of the preceding claims, wherein the at least one first air filter (13) is via guiding rails (10) of the first air filter unit (7) slideably insertable to and slideably removable from the first air filter unit (7), or wherein the at least one first air filter (13) is along the main air flow direction (4) insertable into the first air filter unit (7) till a contact portion (36) of the first air filter (13) reaches a counterpart shoulder portion (37) of the first air filter unit (7) and is against the main air flow direction (4) removable out of the first air filter unit (7).

5. The air filtering device (1) according to claim 4, wherein the at least one first air filter (13) is in the maintenance position (24) of the first air filter unit (7) slideably insertable and slideably removable from the first air filter unit (7) along the gravitational direction (27), or wherein the at least one first air filter (13) is in the maintenance position (24) of the first air filter unit (7) slideably insertable and slideably removable from the first air filter unit (7) in a direction perpendicular with respect to the gravitational direction (27).

6. The air filtering device (1 ) according to claim 4 or 5, wherein the counterpart shoulder portion (37) of the first air filter unit (7) forms at least a portion of the track system (9) enabling the slide movement (26) for moving the first air filter unit (7) from the operation position (23) to the maintenance position (24).

7. The air filtering device (1) according to any one of the preceding claims, wherein at least in the maintenance position (24) the electrostatically chargeable fibers (14) hang in the first air filter unit (7) such that the loose end (15) of each fiber (14) is arranged below the connecting portion (16) with respect to the gravitational direction (27).

8. The air filtering device (1) according to any one of the preceding claims, wherein the fibers (14) of the at least one first air filter (13) extend along the main air flow direction (4) beyond the first air filter unit (7) in the operating position, and wherein the air moving unit (6) is configured to be switched on when the first air filter unit (7) is moved from the maintenance position (24) to the operating position (23), for positioning the fibers (14) in the air filtering device (1).

9. The air filtering device (1) according to any one of the preceding claims, wherein each of the first air filters (13) comprises: a. a plurality of adjacently arranged elongated lamellas (17), on which the fibers (14) are connected via the connecting portion (16), b. two bands (18), one of which being connected to one longitudinal end of the elongated lamellas (17) and the other one of which being connected to the other longitudinal end of the elongated lamellas (17) thereby forming the first air filter (13).

10. The air filtering device (1) according to claim 9, wherein the bands (18) comprises a cross section profile, which corresponds at least partially with the portion of the first air filter unit (7), in particular which forms the guiding rails (10), for slideably inserting and slideably removing of the at least one first air filter (13) to and fromthe first air filter unit (7), or wherein at least one of the bands (18) form at least partially the contact portion (36) of the first air filter (13).11 . The air filtering device (1) according to any one of the preceding claims, wherein the first air filter unit (7) comprises a plurality of adjacently arranged first air filters (13), wherein a sealing (19) is arranged between the adjacently arranged first air filter (13) and I or between a housing wall of the first air filter unit (7) and the first air filters (13) for reducing bypass flow in operation of the air filtering device (1), or wherein a plurality of first air filter units (7) each comprising the first air filter (13) are arranged adjacent in the air filter unit housing (35).

12. The air filtering device (1) according to any one of the preceding claims, wherein the fibers (14) of two adjacently arranged first air filters (13) are configured to interfere with each other during operation of the air filtering device (1) or wherein the fibers (14) of two adjacently arranged first air filters (13) are separated during operation of the air filtering device (1) by the plurality of first air filter units (7), in which the first air filters (13) are arranged.

13. The air filtering device (1) according to any one of the preceding claims, wherein the first air filter unit (7) comprises a releasable lock mechanism (20), configure to rigidly position the at least one first air filter (13) within the first air filter unit (7) in the operating position (23) and configured to release the at least one first air filter (13) in the maintenance position (24) such that the at least one first air filter (13) is removable from the first air filter unit (7).

14. The air filtering device (1) according to any one of the preceding claims, wherein the first air filter unit (7) comprises a bracket (11) or a plurality of brackets (11), which are configured to enable to mount in the maintenance position (24) of thefirst air filter unit (7) a filter bag (22), in which the at least one first air filter (13) is disposable.

15. The air filtering device (1) according to any one of the preceding claims, wherein the first air filter unit (7) forms a circumferential portion of the outer hull (32) of the air filtering device (1), in particular wherein the first air filter unit (7) forms the outer hull of the air filtering device (1) in all directions, besides the direction which is directed to the air moving unit (6) when the first air filter unit (7) is positioned in its operation position (23).

16. The air filtering device (1) according to any one of the preceding claims, wherein the air filtering device (1) further comprises at least one pressure sensor (21), which is arranged in the air filtering device (1), and which is configured to provide a pressure signal, which is characteristic for the pressure of the air streaming through the air filtering device (1) in its operation, wherein the pressure signal is used to determine if maintenance of the air filtering device (1) is required.

17. The air filtering device (1) according to any one of the preceding claims, wherein the first air filter unit (7) comprises a unit housing wall (38), which forms at least partially a streaming channel within which the electrostatically chargeable fibers (14) of the air filter (13) are at least partially arranged.

18. The air filtering device (1) according to claim 17, wherein the unit housing wall (38) is arranged tapered along the electrostatically charged fibers (14), thereby compressing at least partially the electrostatically charged fibers (14) of the air filter (13).

19. A method of maintaining an air filtering device (1), the method comprising the steps of:a. Providing (S1) an air filtering device (1) according to any one of the preceding claims; b. Moving (S2) a first air filter unit (7) of the air filtering device (1) form an operating position (23) in a maintenance position (24); c. Replacing (S3) at least one of the first air filters (13) of the first air filter unit (7).

20. The method according to claim 16, wherein the method further comprises the step of: a. Determining (S1 A) if maintenance of the air filtering device (1) is required, in particular by using the pressure signal from the pressure sensor (22).

Images