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Title:
AIR TREATMENT DEVICE
Document Type and Number:
WIPO Patent Application WO/2017/222457
Kind Code:
A1
Abstract:
The present specification relates to an air treatment device adapted to be arranged to be fluidly connected to an opening in an element comprised by an envelope of a building, the element comprising a first surface adapted to face an exterior space outside of the building and a second surface adapted to face an interior space of the building, the opening extending between the first and second surface. The air treatment device comprises a housing comprising an inlet, and an outlet and an air treatment section arranged in the housing operable to treat a flow of air drawn from the exterior of the building into the interior space of the building, comprising means for generating the flow of air, a filter and an ionizing unit. The ionizing unit is arranged upstream of the filter with respect to a direction of flow from the exterior space to the interior space.

Inventors:
HELGESSON, Klas (Postbox, 104 51 Stockholm, 104 51, SE)
HELIN, Emil (Postbox, 104 51 Stockholm, 104 51, SE)
KORLING, Sebastian (Postbox, 104 51 Stockholm, 104 51, SE)
SKÅNTORP, Johan (Postbox, 104 51 Stockholm, 104 51, SE)
Application Number:
SE2017/050667
Publication Date:
December 28, 2017
Filing Date:
June 20, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
BLUEAIR AB (Karlavägen 108, Stockholm, 115 26, SE)
International Classes:
B03C3/155; A61L9/22; F24F3/16; F24F7/013; B01D46/10; F24F1/02
Domestic Patent References:
WO2001028692A12001-04-26
Foreign References:
US4884416A1989-12-05
EP1433516A22004-06-30
DE202013100972U12014-06-12
GB1587983A1981-04-15
US3422263A1969-01-14
GB2308320A1997-06-25
Attorney, Agent or Firm:
AWAPATENT AB (Box104 30 Stockholm, 104 30, SE)
Download PDF:
Claims:
CLAIMS

1 . Air treatment device (1 ) adapted to be arranged to be fluidly connected to an opening in an element comprised by an envelope of a building, such as a wall, a window or a roof, said element comprising a first surface adapted to face an exterior space outside of the building and a second surface adapted to face an interior space of the building, said opening extending between said first and second surface, said air treatment device comprising: a housing (100) comprising:

an inlet;

an outlet; and an air treatment section (200) arranged in said housing between said inlet and said outlet, said air treatment section being operable to treat a flow of air drawn from the exterior of the building into the interior space of the building, said air treatment section comprising:

a cylindrical portion (122);

means for generating said flow of air (220);

a filter (21 1 ; 212; 213); and

an ionizing unit (230) arranged in said cylindrical portion; wherein said ionizing unit is arranged upstream of said filter with respect to a direction of flow from said exterior space to said interior space and said ionizing unit is comprising

at least one emitting electrode (231 );

at least one collecting electrode; and

wherein said collecting electrode is arranged on the internal surface of the cylindrical portion. Air treatment device according to claim 1 , wherein said housing comprises a first portion adapted to be arranged at least partly within said opening defined between said first and second surface.

Air treatment device according to claim 1 or 2, wherein said housing comprises a second portion adapted to be arranged at least partly in said interior space.

Air treatment device according to claim 3, wherein at least one of said means for generating said flow of air and said filter is/are arranged in said second portion.

Air treatment device according to any of the preceding claims 2-4, wherein at least one of said means for generating said flow of air and said ionizing unit is/are arranged in said first portion of said housing.

Air treatment device according to any of the preceding claims, wherein said first portion of said housing is adapted to be arranged at least party in said exterior space outside of said building.

Air treatment device according to any of the preceding claims, wherein said device is adapted to be arranged such that a continuous fluid path is formed by said opening and said inlet.

Air treatment device according to any of the preceding claims, wherein said means for generating said flow of air comprises a fan.

Air treatment device according to any of the preceding claims, further comprising a controller configured to control said air treatment section.

10. Air treatment device according to claim 10, wherein said controller is adapted to control said air treatment section based on received sensor data, wherein said sensor data is indicative of at least one condition of the air present in said interior space.

Description:
AIR TREATMENT DEVICE

Field of the invention

The present invention generally relates to the field of air treatment 5 devices. In particular, the present invention relates to air treatment devices adapted to be arranged in an opening in an envelope of a building, such as a wall or a window.

Technical background

Air pollution levels, where examples of hazardous pollutants include Particular Matter (PM), Volatile Organic Compounds (VOC) and carbon dioxide (CO2), are increasing all over the world, especially in urban areas. For5 example air pollution levels in many large Asian cities are now well above recommendations made by the World Health Organization.

Since many people spend a considerable amount of their life indoors, many solutions proposed to the problem of hazardous pollutions are related to treatment, i.e. cleaning, of indoor air. For example, in order to improve the0 quality of indoor air, air treatment devices are used for example for cleaning of indoor air in indoor spaces of for example buildings. Conventional air treatment devices normally comprise an air treatment section adapted to remove pollutants from an air stream guided through the device. Typically, the air treatment section in such devices comprises a fan for generating the air5 stream to be treated by the air treatment section. Further, such an air

treatment section commonly comprises one or more filters such as HEPA- filters and/or filters comprising active carbon.

Such air treatment devices and filters enable control over particular matter and VOC:s in the air, the CO2-concentration however may only be0 affected by an air exchange. This is many cases provided by simply

introducing outdoor air into the indoor space by means of for example opening a window. However, although the C02-levels are typically lowered by means of such an introduction, there is a considerable risk that the pollutants levels, for example PM-values, may be increased. Also, the more efficient the decrease of the C02-levels is due to introduced outside air, the more the pollutants level potentially rise.

In order to alleviate some of these drawbacks, solutions have been proposed to introduce outdoor air into indoor spaces of for example buildings comprising different solutions for removing pollutants. Examples include so called HVAC-systems, where air is introduced for example by means of ventilation duct systems and may be treated, i.e. cleaned, by means of equipment comprised by the system. Such systems however tend to be large and complicated and therefore expensive to install. Further, due to a high number of comprised components, such systems generally require large amounts of energy for their operation. Hence both investment- and operating costs for providing the outdoor air tend to be high. Further, installing such systems in an existing building may require large and costly modifications to the building.

Summary of the invention

Accordingly, it would be desirable to be able to provide outdoor air to an indoor environment in a less costly and less complicated manner. In particular, it would be desirable to provide air fulfilling requirements relating to health concerns, such as levels of pollutants present in the air, in a manner requiring little effort for a user with regards to installation, maintenance and the like.

To better address one or more of these concerns a system and a method for managing a condition of air in an enclosed environment as defined in the independent claim are provided. Preferred embodiments are defined in the dependent claims.

According to one aspect of the invention, an air treatment device adapted to be arranged to be fluidly connected to an opening in an element comprised by an envelope of a building, such as a wall, a window or a roof, is provided. The element comprising a first surface adapted to face an exterior space outside of the building and a second surface adapted to face an interior space of the building, the opening extending between the first and second surface. The air treatment device comprises a housing comprising an inlet, and an outlet and an air treatment section arranged in the housing between the inlet and the outlet, the air treatment section being operable to treat a flow of air drawn from the exterior of the building into the interior space of the building. The air treatment section comprises means for generating the flow of air, a filter and an ionizing unit, wherein the ionizing unit is arranged upstream of the filter with respect to a direction of flow from the exterior space to the interior space.

According to the first aspect, the air treatment device provides an inventive solution to the concerns described above derived from the

realization that the desired characteristics may be provided by a design wherein an air treatment device is adapted to be arranged to be fluidly connected to an opening in an element comprised by an envelope of a building, such as a wall, a window or a roof, while also comprising an air treatment section adapted to treat the air drawn from the outside. Hereby, outside air may for example be drawn directly from the outside space into the air treatment device in order to be treated, for example by removal of pollutants such as particular matter and/or VOC:s, before being discharged into the interior space. Accordingly, for example, the CO2 levels in the interior space may be reduced by the introduction of outdoor air, while the pollutants levels in the room simultaneously may be kept at a desired, low level by means of the efficient treatment, or cleaning, of the outside air before allowing the air to enter the interior space. In some cases, levels of certain VOC:s primarily generated indoors, where examples include formaldehyde, may also be advantageously reduced by such an introduction of outside air.

Further, the design wherein the air treatment device comprises a housing in which the air treatment section is arranged and through which the outdoor air may be drawn, provides a convenient, possibly self contained, arrangement which is easy for a user to install for example in a room in a building or office space and further has a discrete and pleasing appearance. The disclosed air treatment device is suitable for use in any type of interior space in for example a building such as a room in an apartment building, a room in a detached- or terrace house, an office or other business premises. More particularly, the air treatment device is adapted to be arranged in fluid contact with an opening in an envelope of such a building, wherein examples include an outer wall, a ceiling, an entrance door or a window. In the latter case, embodiments are conceivable wherein the opening is an opening such as a hole in a window glass or where the opening constitutes a removed portion of the window. Accordingly, examples include embodiments arranged at least partly within an outer wall, embodiments adapted to extend through a hole in a window glass sheet and freestanding embodiments adapted to be arranged in a window opening.

Further, in some embodiments, the air treatment device and/or the housing may be adapted to be arranged in proximity of the opening and/or possibly at least partly covering the opening. The opening may in such embodiments be covered on or at the first surface of the building element, the second surface of the building element or both.

Suitable material for structural parts of the air treatment device includes metal, such as sheet metal, particularly for parts of the air treatment device visible to a user when installed. For some embodiments and/or parts, plastics such as polypropylene may be suitable.

The air treatment section may comprise one or more filters, where examples include filters adapted for filtering the air stream from particles as well as filters adapted to remove gaseous pollutants. Examples include non- woven polypropylene particle filters, activated carbon filters, and combined filters. In some embodiments, the filter comprises a material adapted to attract charged particles. For example, the filter medium may include a dielectric material, such as polypropylene.

The air treatment section further comprises an ionizing unit, which as described above, is arranged upstream of the filter. This is advantageous for example in that the ionizing unit may charge particles flowing by in the air stream which may increase the likelihood for the particles to be subsequently trapped by the filter. The means for generating the air stream may however be arranged on any side of the ionizing unit, as well as on any side of the filter. Accordingly, in some embodiment, the air may be drawn through the filter by for example a fan arranged downstream of the filter whereas in other embodiment, the air may be pushed through the filter by means of for example a fan arranged upstream of the filter.

The air treatment device may further be adapted to be connected to an electricity supply network. In some embodiment, the air treatment device may comprise a cord and for example a plug contact to provide such a connection. In other embodiment, cords adapted for a fixed connection to a network may be provided. In some embodiments, energy may be supplied to the air treatment device from a solar cell or solar panel. Such a solar cell or panel may for example be arranged on the exterior second surface of the building element, possibly in vicinity of the opening, and be suitably connected to the device.

The air treatment device in some embodiment comprises suitable fastening means for attaching the device to for example a wall, such means may be arranged for example on a surface adapted to face the wall or window or the like. Examples of such means include screws and adhesives. In some embodiments, the air treatment device comprises means adapted to mate, or cooperate, with corresponding fastening means arranged on the wall or similar structure. According to one embodiment, the housing comprises a first portion adapted to be arranged at least partly within said opening defined between said first and second surface. In some embodiments, the first portion of the housing may extend from the first surface to the second surface, in other embodiment the first portion may extend along a portion of the path defined through the opening. This is advantageous for example in that the air treatment device may be easily arranged in the opening in for example a wall, hereby conveniently providing a flow of outdoor air into an indoor space, while at the same time purifying the introduced air thereby providing high quality air into the indoor environment. Further, in some embodiment, the first portion may form part of a suspension arrangement adapted to hold the air treatment device, for example on a wall, at least in proximity of the opening by means of a form fitting or the like between the first portion and the opening. According to one embodiment, the housing comprises a second portion adapted to be arranged at least partly in the interior space. For example, a portion of the housing may be adapted to be arranged on or at the second surface of the element of the building, such as on the wall or window, i.e. on an interior side thereof. In some embodiments, the second portion of the housing may be adapted to be arranged in proximity of the opening and/or possibly covering the opening.

According to one embodiment, at least one of the means for generating the flow of air and the filter is/are arranged in the second portion. This is advantageous at least in that the filter and/or air flow capacity of the air treatment device may be chosen independent of the size of the opening in for example a wall, since no constraints are put on the size and shape of the second portion of the housing adapted to be arranged in the interior space. Further, a convenient layout for the user may be achieved in that the filter is easily accessible for example when the filter has to be changed.

According to one embodiment, at least one of the means for generating the flow of air and the ionizing unit is/are arranged in the first portion of the housing. This is advantageous for example in that possible noise generated by means of the means for generating the flow of air may be suppressed or damped. Further, in some environments, the discrete appearance provided by such an embodiment is required. Moreover, the ionization or the air may in some embodiments benefit from being arranged in an opening having a suitable shape such as a circular shape.

Accordingly, in some embodiments, the housing may comprise a first and a second portion such that the air treatment device is adapted to be arranged partly in the opening in the envelope of the building and partly within the interior space of the building and/or the exterior of a building. For example, in one exemplary embodiment, the air treatment device comprises a housing having a first portion adapted to extend into the opening, possibly comprising an ionizing unit and a second portion adapted to be arranged in the interior space, possibly comprising a fan and a filter.

In other embodiment, the air treatment device may be arranged completely within the opening extending through for example the wall.

Accordingly, the filter, ionizing unit and for example a fan may be arranged within the opening, i.e. in the space within the building element.

In yet other embodiments, the air treatment device may be arranged completely within the internal space, for example a room. Accordingly, the filter, ionizing unit and for example a fan may be arranged for example in a housing arranged in the room, but however in fluid contact with the opening such that a flow of air may be drawn from the outside.

According to one embodiment, the second portion is adapted to be removably attached to the first portion. The first and second portion may be attached for example by means of form fit, press fit or other geometrical fittings or by means of separate attachment means.

In many embodiments however, the first and second portion constitute integral parts of a housing structure. In one embodiment, the air treatment device further comprises a pipe shaped structure adapted to extend between the first and second side, thereby forming a fluid channel through the opening in the element comprised by an envelope of the building. Examples include a pipe, a hose or similar.

In one embodiment, the air treatment device further comprises a protecting element adapted to be arranged adjacent to said opening in the exterior space outside of the building. Examples of advantageous designs include a weather protection cover adapted to protect the opening in the wall from for the elements outside such as wind or rain. Such a protecting element may be adapted to be removably attached to the opening as such, to a pipe extending through the opening and/or to the first portion described above. The protecting element may in some embodiment form part of the first portion of the housing.

In some embodiments, the air treatment device may comprise an exterior portion adapted to be arranged at least partly in the exterior space, such that at least one of the fan and the filter may be arranged in the exterior portion.

According to one embodiment, a portion of the housing comprises a circular cross section, wherein the radius of the cross section lies in a range between 50 and 200 mm, preferably between 75 and 150 mm. Such a sizing is advantageous in that the portion may be arranged in a vent hole of a common, or even standardized, size which facilitates installation of the device.

According to one embodiment, the device is adapted to be arranged such that a continuous fluid path is formed by the opening and the inlet.

Accordingly, in some embodiment, the housing is adapted to be arranged such that a continuous fluid path is formed by the opening and the inlet. By continuous fluid path should be understood a direct, immediate coupling between the inlet and the opening, together forming the continuous fluid path. For example, the inlet may be arranged to extend into the opening. In other embodiments, the inlet may be adapted to form a continuous continuation of the fluid path formed by the opening between the first and second surface of the building element. Advantages include a compact design as well as lower flow losses since the utilized fluid path may be kept as short as possible.

In one embodiment, the device is adapted to be arranged such that a fluid path is formed between the opening and the inlet by means of an additional component such as a hose, a pipe or a conduit. Advantages include a greater degree of freedom with regards to placement of the device in the interior space.

According to one embodiment, the means for generating the flow of air comprises a fan. Examples of suitable fans include axial fans and radial fans. Fans are however well known in the art and will not be described as such in further detail. The dimensions of the fan may in some embodiments be adapted to the dimensions of the opening in the building element.

In other embodiments, any other suitable means adapted to create, induce, or draw a flow of air, particularly through said air filter are however conceivable within the scope of the present invention. Examples include a compressor or a heat exchanger.

According to one embodiment, the ionizing unit is a unit adapted to charge air borne particles, said unit comprising at least one emitting electrode, at least one collecting electrode and means for applying a voltage to said at least one emitting electrode.

When voltage is applied over the emitter electrode and the collector electrode, an electric field is obtained between the emitter electrode and the collector electrode. Hereby, a phenomena known as corona discharges may occur at the emitter electrode, whereby molecules in the air get charged, i.e. ionized, and turn into ions. The ions travel in the electric field towards the collector electrode and collide with particles present in the air flow conducted by the collector electrode, whereby these particles get charged, i.e. ionized. The particles may then be collected by means of the filter.

According to one embodiment, the emitter electrode is a needle electrode or a carbon fibre brush.

In one embodiment, the collector electrode and/or the emitter electrode may be adapted to be arranged in the opening in the building envelope.

The emitter electrode may in some embodiments be adapted to be arranged so as to be centred with respect to the circular cross section of the inlet and/or the opening in the element comprised by the building envelope.

According to one embodiment, the shape of the collector electrode is adapted to the shape of a circular cross section of the inlet and/or the opening in the element comprised by the building envelope.

Further, other exemplary means for treatment of air that may be comprised by the air treatment device, where examples include devices using ultraviolet radiation, means for humidification of air and/or means for heating or cooling of air. Such means may be arranged such that the flow of air drawn from the outside is for example heated or cooled before entering the interior space.

According to one embodiment, the air treatment device further comprises a controller configured to control said air treatment section. Such control may include, among others, choice of fan speed and ionization current or any other parameter suitable for the air treatment section in question.

In some embodiments, the air treatment device further comprises a user interface such as a graphical user interface, for example a display device or one or more LEDs by which the user may control the air treatment device and/or by means of which information may be provided to the user. Examples include a choice of fan speed by the user, or the provision of an indication of a need for a filter change. Any commands, selections or adjustments by the user may be performed using conventional means such as a button, knob or touch button manoeuvred by the user. Other embodiments may comprise the user interacting with touch- or pressure-sensitive areas of the interface.

According to one embodiment, the controller is adapted to control the air treatment section based on received sensor data, wherein the sensor data is indicative of at least one condition of the air present in the interior space.

In one embodiment, the air treatment device comprises such a sensor arranged to measure for example an average pollutant concentration in the interior space. The air treatment device may however also comprise means for receiving data from an externally arranged sensor arranged to measure an average pollutant concentration in the interior space. Sensors adapted to measure an average pollutant concentration are as such generally known in the art and will not be described in detail, suitable types of sensors however include particle sensors and/or a gas sensor adapted to measure for example VOC or CO2 concentrations.

The air treatment device may in some embodiments comprise means for communication with at least one additional device, such as a sensor, another air treatment device, a server or similar by means of a wired or a wireless connection. Examples include means for providing a WIFI- connection.

According to a second aspect of the invention, a system comprising an air treatment device according to any of the embodiments described in the foregoing and a server is provided. The air treatment device may

communicate by means of a wired or a wireless connection. In some embodiments, the system may comprise additional elements such one or more external sensors, one or more additional air treatment devices and a user terminal such as a smart phone adapted to communicate with the air treatment device and/or the server and to control the air treatment device. Further objectives, advantages and features of the system conceivable within the scope of the third aspect of the invention are readily understood by the foregoing discussion referring to the first aspects of the invention. Further objectives of, features of and advantages with the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims. Those skilled in the art realize that different features of the present invention can be combined to 5 create embodiments other than those described in the following.

Brief description of the drawings

The invention will be better understood through the following illustrative0 and non-limiting detailed description of preferred embodiments, with

reference to the appended drawings, on which:

Figure 1 a is a perspective view of an air treatment device according to one embodiment arranged on a wall;

5 Figure 2 is an exploded view of an air treatment device according to one embodiment;

Figure 3a is a schematic front view of an air treatment device according to one embodiment;

Figure 3b is a schematic cross sectional view of an air treatment0 device according to one embodiment, viewed from above;

All figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.

5

Detailed description of embodiments

An air treatment device 1 according to one embodiment is shown in fig. 1 arranged on a wall W. The illustrated embodiment has the approximately0 dimensions of 200x350 mm and extends about 80 mm from the interior wall surface when mounted. Means for providing electricity to the device (not shown) comprising a cord and for example a plug contact should be provided at a suitable location.

Figure 2 is an exploded view of the embodiment of the air treatment device shown in fig. 1 . The device 1 comprises a housing 100 and an air treatment section 200.

In the illustrated case, the air treatment device comprises a plastic pipe 300 having a circular cross section. The pipe 300 is adapted be arranged in, e.g. extend through, an opening in for example a wall, the opening extending from an exterior space, i.e. outdoors, to an interior space such as a room.

A portion 120 of the housing 100 is adapted to be arranged at least partly, in the illustrated case mainly, within the interior space for example a room. The second portion comprises a boxed shaped, open portion 121 and a tube shaped portion 122 extending, when arranged on the wall, in a direction towards the outside and adapted to be attached to the plastic pipe 300. In other words, the cylindrical portion is adapted to be arranged within the opening in the wall. The box shaped portion constitutes the visual part of the air treatment device, when installed, and is accordingly adapted to be arranged in the interior space, e.g. in a room on the wall. In the illustrated embodiment, the cylindrical portion 122 further constitutes an inlet of the housing.

A front cover 123, preferably made of metal, is adapted to be arranged on the box shaped portion 121 in order to close the structure 121 , 123. The cover may be fastened by means of screws or similar. For safety reasons, the current is turned off should the cover be removed when the air treatment device operates.

The boxed shape portion 121 further comprises a plurality of air openings 121 ' which together constitute an outlet of the air treatment device trough which air is introduced into the room. The openings 121 'are arranged on three sides of the air treatment device, i.e. a left, right and upper surface of the housing oriented as shown in fig. 2.

The back of the box shaped portion preferably comprises suitable fastening means, such as screws or holes adapted to receive screws, such that the device may be securely fastened to a wall or similar.

As shown in fig. 1 , the lower side of the housing comprises a user interface 500 adapted to allow the user to control the device as well as to provide feedback to the user. In the illustrated embodiment, the interface comprises buttons 51 Oa-d for regulation of for example airspeed and a feedback LED-bar 520 adapted to indicate a C02-level to the user. Further, a need for a filter change may be indicated by means of a second LED-indicator (not shown). Turning again to fig. 2, a weather protection cover 400 is adapted to be arranged at least partly, in the illustrated case mainly, in the exterior or outside space. The cover 400 comprising a first square shaped portion 410 in the form of a protecting plate comprising openings 410' adapted to allow a flow of air to be drawn into the pipe 300 and further into the room via the second portion 120 of the housing 100. A tube shaped portion 420 extends, when arranged on the wall, in a direction towards the inside and is adapted to be attached to the plastic pipe 300.

The air treatment section 200 comprises a filter 210, a fan adapted to create a flow of air (not shown in fig. 2) and an ionizing unit (also not shown in fig. 2). The filter 210, or filter unit 210, is arranged in the boxed shape portion 121 of the second portion 120 of the housing 100.

Fig. 3a and b are schematic illustrations of the embodiment of the air treatment device 1 shown in fig. 2 and 3 in front view and top view in cross section respectively. Fig. 3a shows a schematic front view of the embodiment of the air treatment device 1 , more particularly, the interior of the box shaped portion 121 is illustrated comprising a fan 220 arranged to be substantially centred with respect to the cylindrical portion 122, and consequently to the opening in the wall when mounted, and three filter units 21 1 , 212, 213. The three filter units are elongated filter units extending, when installed, along an upper side U and along the respective sides S1 , S2. The filters may be any type of filters suitable to catch for example particles and/or gas molecules.

The fan 220 is a radial fan, i.e. adapted to draw a flow of air from the outside through the pipe 300, i.e. en an axial direction of the fan, and to distribute the air sideways, i.e. in a radial direction of the fan such that the air flows through the filters 21 1 , 212, 213 before leaving the device through the openings 121 ' in the surrounding walls of the box shaped portion 121 .

At a fourth side B, i.e. the bottom side when arranged on the wall, a chamber 140 is provided, this chamber is adapted to accommodate logics and electronics, e.g. the controller of the device (not shown). Other example of electronics which may be arranged in the chamber or compartment is a printed circuit board, PCB, LED:s, buttons and sensors and communication means such as a radio transceiver, a WIFI-transceiver and or means for providing a wired communication connection. The adjacent, lower side of the housing advantageously comprises a user interface (shown in fig. 1 ), hereby only a short distance has to be covered by wiring connecting the user interface and the electronics.

Turning to fig. 3b, the layout of the embodiment of the device when arranged in the opening O, in the illustrated case an opening O in a wall W is further elucidated in cross section. In the illustrated case, the opening O extends between a first surface WO adapted to face an exterior space outside of the building and a second surface Wl adapted to face an interior space of the building such as a room. Fig. 3 hereby shows the box shaped structure 120, the plastic pipe 300 and the weather protecting cover 400 and further how the elements 120 and 400 are connected to the plastic pipe 300 by means of the respective cylindrical portions of elements 120, 130 being inserted into the pipe. If necessary in order to provide an air tight seal, gaskets or similar structures may be provided at the interface between the respective cylindrical portion and the pipe. Further, insulation may optionally be arranged around, i.e. on the outside of, the pipe in order to prevent any air from entering into the building.

The device 1 is arranged such that the fan 220 is placed centred in front of the pipe 300 such that a flow of air may be drawn through the pipe 300, whereas the filter units 21 1 , 212, 213 are arranged around the fan such that a flow of air in a radial direction is provided through the filters 21 1 , 212, 213 and into the room. This flow of air is illustrated by the dashed arrows in fig. 3b. An ionizing unit 230 is arranged in the tube shaped portion 122 extending into plastic pipe 1 10. A cathode, or emitting electrode 231 , is arranged at the centre of the tube shaped portion, on the internal surface of the tube shape portion a cylindrical collecting electrode, for example in the form of a metallic tape, is arranged further functioning as a ground for the ionizing cathode. This creates a magnetic field over the cross section of the pipe charging particles flowing by in the air stream which in turn increases the likelihood for the particles to be subsequently trapped by the filter.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. The skilled person understands that many modifications, variations and alterations are conceivable within the scope as defined in the appended claims.

Additionally, variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.