TECHNICAL FIELD

The present invention relates to an air purification device for separating airborne particles from a flow of air in an air duct.

BACKGROUND

Within many different technical fields, like for example different types of vehicles or buildings, air filtration systems are used to ensure the desired air quality within the cabin or building or other closed space.

Such filtration systems may comprise an air purification device for separating airborne particles from a flow of air in an air duct, where said air purification device comprises an ionizing unit that is configured to produce an ionizing volume for electrically charging particles in the air, and a filter medium arranged downstream the air flow path, said filter medium being arranged to attract at least a subset of the charged airborne particles.

Such an ionizing unit may comprise an emitter electrode having one or more corona discharge protrusions, and a collector electrode. The collector electrode may be connected to ground, such that ions are produced in a volume surrounding a corona discharge protrusion of the emitter electrode when a high voltage is applied over the emitter electrode and the collector electrode. The volume in which ions are produced is referred to as ionizing volume and the emitter and collector electrodes are preferably arranged such that the ionizing volume spans the flow path. When particles pass through the ionizing volume at least a portion of the particles are charged. The charged particles then adhere to the filter medium downstream the air flow path. Air ducts, e.g. air ducts in heating, ventilation and air conditioning systems (HVAC), are commonly provided in non-conductive material, usually plastics. During an ionizing operation, some of the ions by charging said emitter electrode may get stuck on surfaces within the air duct, e.g. surfaces of such air ducts made non-conductive plastics, depressing the corona discharge process needed to create the ionizing volume.

WO201 9182504 A1 discloses an ionizing arrangement for electrically charging particles in an air flow in an air duct, said ionizing arrangement comprising a shielding electrode arranged within the air duct, said shielding electrode being arranged to provide shielding of an electromagnetic field emanating from a corona electrode. The shielding electrode is configured to provide a Faraday cage, providing a more controlled electrical environment. Such an ionizing arrangement may require more space and a complex design. Further, control of the Faraday cage potential may be required in order to avoid current runaway.

There is thus a need for providing an air purification device facilitating efficient ionization operation and may be provided such that it may be applied where space for the ionizing unit of the air purification device is restricted.

OBJECTS OF THE INVENTION

An object of the present disclosure is to provide an air purification device which seeks to mitigate, alleviate, or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination.

An object of the present invention is to provide a space efficient air purification device which facilitates efficient ionization operation. SUMMARY

These and other objects, apparent from the following description, are achieved by an air purification device as set out in the appended independent claim. Preferred embodiments of the air purification device are defined in appended dependent claims.

Specifically, an object of the invention is achieved by an air purification device for separating airborne particles from a flow of air in an air duct. The air purification device comprises an ionizing unit arranged, during an ionizing operation, to produce an ionizing volume for charging airborne particles present in the flow of air. The ionizing unit comprises at least one emitter electrode having at least one emitter discharge protrusion and being configured to be charged for generating ions, and at least one collector electrode. The air purification device comprises a filter medium arranged to attract at least a subset of the charged airborne particles. Said ionizing unit comprises one or more neutralizing discharge protrusions having a different potential than said emitter electrode, said one or more neutralizing discharge protrusions being arranged such that, if one or more surfaces within said air duct are charged by means of at least a subset of said ions generated by charging said at least one emitter electrode, generation of ions with an opposite charge to the ions generated by charging said at least one emitter electrode is facilitated based on said one or more charged surfaces, so as to facilitate at least partly neutralizing said one or more charged surfaces within said air duct. Said generation, by means of said one or more discharge protrusions of said at least one collector electrode, of ions with an opposite charge to the ions generated by charging said at least one emitter electrode, is based on said opposite charge of said one or more charged surfaces within said air duct. Neutralization of surfaces here refers to the charge of said one or more surfaces being reduced due to ions of opposite polarity being attracted to the one or more charged surfaces, the opposite polarities providing said neutralization. Hereby an air purification device which facilitates efficient ionization operation is provided. Hereby an air purification device which may be applied where space for the ionizing unit of the air purification device is restricted and facilitates providing efficient air purification during an ionizing operation. Such an air purification device may be space efficiently designed and still facilitate efficient ionizing operation for efficient air purification. Hereby an ionizing operation is facilitated, which stabilizes on a given potential of the surroundings within said air duct, where ions of opposite polarity, i.e. positive and negative ions, balances each other.

According to an aspect of the air purification device, said one or more neutralizing discharge protrusions are arranged such that, during said ionizing operation, when one or more surfaces within said air duct are charged by means of at least a subset of said ions generated by charging said at least one emitter electrode, a potential difference between said one or more charged surfaces and said one or more neutralizing discharge protrusions is created. Said potential difference generates said oppositely charged ions in connection to said one or more neutralizing discharge protrusions based on said created potential difference, wherein said oppositely charged one or more surfaces attract ions of said oppositely charged ions so as to facilitate said at least partly neutralization of said one or more surfaces. Hereby an air purification device which facilitates efficient ionization operation is provided. Hereby a space efficient air purification device which facilitates efficient ionization operation may be provided. Hereby an ionizing operation is facilitated, which stabilizes on a given potential of the surroundings within said air duct, where ions of opposite polarity, i.e. positive and negative ions, balances each other on said one or more surfaces.

According to an aspect of the air purification device, said one or more neutralizing discharge protrusions are arranged such that, during said ionizing operation, when one or more surfaces within said air duct are charged by means of at least a subset of said ions generated by charging said at least one emitter electrode, an additional electrical field is created in connection to said one or more neutralizing discharge protrusions based on said charged one or more surfaces. Said ions with opposite charge to the ions generated by charging said at least one emitter electrode are hereby generated in connection to said one or more neutralizing discharge protrusions based on said created additional electrical field, wherein said charged one or more surfaces attract ions of said oppositely charged ions so as to facilitate said at least partly neutralization of said one or more surfaces. Hereby an air purification device which facilitates efficient ionization operation is provided. Hereby a space efficient air purification device which facilitates efficient ionization operation may be provided. Hereby an ionizing operation is facilitated, which stabilizes on a given potential of the surroundings within said air duct, where ions of opposite polarity, i.e. positive and negative ions, balances each other on said one or more surfaces.

According to an aspect of the air purification device, during said ionizing operation, when said at least one emitter electrode having at least one emitter discharge protrusion is configured to be charged for generating ions, said ions are generated based on an electrical field created in connection to said at least one emitter discharge protrusion. When one or more surfaces within said air duct are charged by means of at least a subset of said ions generated by charging said at least one emitter electrode, said electrical field, having the same polarity as the thus charged one or more surfaces, is supressed. Hereby ions with opposite charge are generated, in connection to said one or more neutralizing discharge protrusions, by means of said electrical field thus created based on said charged one or more surfaces. Said charged one or more surfaces attract ions of said oppositely charged ions so that at least partly neutralisation of said charged one or more surfaces is facilitated and thereby facilitating re-building the supressed electrical field so that generation of ions in connection to said at least one emitter discharge protrusion is facilitated. Hereby an air purification device which facilitates efficient ionization operation is provided. Hereby a space efficient air purification device which facilitates efficient ionization operation may be provided. Such a solution with provision of neutralizing discharge protrusions for collector electrodes of the ionizing unit facilitates easy modification of existing air purification devices in that it is only required to add discharge protrusion for said collector electrode(s) in order to facilitate improved efficiency in the ionization operation. Hereby an ionizing operation is facilitated, which stabilizes on a given potential of the surroundings within said air duct, where ions of opposite polarity, i.e. positive and negative ions, balances each other on said one or more surfaces.

According to an aspect of the air purification device, said at least one emitter electrode is connected to a negative voltage and the at least one collector electrode to ground or a positive voltage, or wherein the at least one emitter electrode is connected to a positive voltage and the at least one collector electrode to ground or a negative voltage. Thus, said at least one collector electrode has a different potential than said at least one emitter electrode. According to a preferred aspect of the present disclosure, said at least one emitter electrode is connected to a negative voltage and the at least one collector electrode is connected to ground. According to an aspect of the present disclosure, said one or more neutralizing discharge protrusions are associated with said at least one collector electrode so that they have essentially the same potential as said at least one collector electrode. According to an aspect of the present disclosure, said one or more neutralizing discharge protrusions are conductively connected to said at least one collector electrode. According to an alternative aspect of the present disclosure, said one or more neutralizing discharge protrusions have a potential different than the potential of said at least one emitter electrode and a different potential than said at least one collector electrode. According to an aspect said one or more neutralizing discharge protrusions may be connected to a positive voltage or connected to ground or to a negative voltage, given that said one or more neutralizing discharge protrusions has a different potential than said at least one emitter electrode and hence a different potential than said one or more emitter discharge protrusions. According to an aspect the air purification device further comprises: a power supply device, a first connector arrangement connecting the power supply device to the at least one emitter electrode; and a second connector arrangement connecting the power supply to the at least one collector electrode. According to an aspect, said power supply device, said first connector arrangement, and said second connector arrangement are comprised in said ionizing unit of said air purification device. According to an aspect of the present disclosure, if said one or more neutralizing discharge protrusions are configured to have a different potential than said at least one emitter electrode and a different potential than said at least one collector electrode, said air purification device further comprises a third connector arrangement connecting the power supply to said one or more neutralizing discharge protrusions. According to an aspect of the present disclosure, the potential of said one or more neutralizing discharge protrusions is controlled by connection to a specific potential.

According to an aspect of the air purification device, said power supply device comprises a current regulator configured to operate said ionizing unit by means of an essentially constant current. By thus operating said ionizing unit by means of an essentially constant current the ionization operation may be performed without the efficiency of the ionization operation being negatively affected. Said power supply device, e.g. said current generator of said power supply device, may, during an ionization operation, need to make certain adaption of the voltage in order to keep said essentially constant current. According to an aspect of the present disclosure said power supply device comprises or is operably connectable to an electronic control unit configured to facilitate controlling said current regulator based on determined information comprising moisture content of the flow of air. Such an electronic control unit is according to an aspect an integrated part of said current regulator. Such an electronic control unit is according to an aspect operably connectable to said current regulator. According to an aspect of the air purification device, said one or more of said one or more neutralizing discharge protrusions are configured to be arranged in connection to one or more of said surfaces within said air duct so as to facilitate generating, based on the charge of said charged one or more surfaces, a proper amount of oppositely charged ions to be attracted to said one or more charged surfaces for facilitating at least partly neutralizing said one or more surfaces within said air duct. Hereby more efficient ionizing operation is facilitated in that said at least partly neutralization of charged surface(s) within said duct is facilitated due to the thus arranged neutralizing discharge protrusions in connection to said surface(s). Hereby avoidance of neutralization of already charged particles in the flow of air by means of oppositely charged ions is facilitated due to the thus arranged neutralizing discharge protrusions in connection to said surface(s). Hereby avoidance of oppositely charging particles in the flow of air by means of oppositely charged ions is facilitated due to the thus arranged neutralizing discharge protrusions in connection to said surface(s). According to an aspect of the present disclosure, said one or more neutralizing discharge protrusions are arranged closer to one or more surfaces of said surfaces within said air duct than said one or more emitter discharge protrusions of said at least one emitter electrode, for facilitating more efficient ionization operation.

According to an aspect of the air purification device, said one or more of said one or more neutralizing discharge protrusions are configured to be directed towards said one or more of said surfaces within said air duct. Hereby more efficient ionizing operation is facilitated in that said at least partly neutralization of charged surface(s) within said duct is facilitated due to the thus arranged neutralizing discharge protrusions in connection to said surface(s). Hereby avoidance of neutralization of already charged particles in the flow of air by means of oppositely charged ions is facilitated due to the thus arranged neutralizing discharge protrusions in connection to said surface(s). Hereby avoidance of oppositely charging particles in the flow of air by means of oppositely charged ions is facilitated due to the thus arranged neutralizing discharge protrusions in connection to said surface(s).

According to an aspect of the air purification device, said one or more surfaces within said air duct comprises one or more inner surfaces of said air duct and/or one or one or more surfaces of said filter medium.

According to an aspect of the air purification device, the number of emitter discharge protrusions of said at least one emitter electrode is larger than the number of neutralizing discharge protrusions of said one or more neutralizing discharge protrusions. Hereby more efficient ionizing operation is facilitated in that said at least partly neutralization of charged surface(s) within said duct is facilitated due to the thus reduced number of neutralizing discharge protrusions relative to the number of emitter discharge protrusions. Hereby avoidance of neutralization of already charged particles in the flow of air by means of oppositely charged ions is facilitated due to the thus reduced number of neutralizing discharge protrusions relative to the number of emitter discharge protrusions.

According to an aspect of the air purification device, said ionizing unit comprises a support arrangement for supporting said at least one emitter electrode and said at least one collector electrode.

According to an aspect of the air purification device, one or more neutralizing discharge protrusions of said one or more neutralizing discharge protrusions is connected to said support arrangement. Hereby more efficient ionizing operation is facilitated in that said at least partly neutralization of charged surface(s) within said duct is facilitated due to the thus connected neutralizing discharge protrusions to said support arrangement. Hereby avoidance of neutralization of already charged particles in the flow of air by means of oppositely charged ions is facilitated due to the connected neutralizing discharge protrusions to said support arrangement. Hereby avoidance of oppositely charging particles in the flow of air by means of oppositely charged ions is facilitated due to the connected neutralizing discharge protrusions to said support arrangement.

According to an aspect of the air purification device, said one or more neutralizing discharge protrusions are associated with said at least one collector electrode. According to an aspect of the present disclosure, said one or more neutralizing discharge protrusions have essentially the same potential as said at least one collector electrode. According to an aspect of the present disclosure, said one or more neutralizing discharge protrusions are conductively connected to said at least one collector electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present disclosure reference is made to the following detailed description when read in conjunction with the accompanying drawings, wherein like reference characters refer to like parts throughout the several views, and in which:

Fig. 1 a-c schematically illustrates a view in the air flow direction of a of an air purification device, arranged within an air duct, at different stages of an ionizing operation according to an aspect of the present disclosure;

Fig. 2a schematically illustrates a view in the air flow direction of an air purification device according to an aspect of the present disclosure;

Fig. 2b schematically illustrates a cross-sectional view of the air purification device in fig. 2a according to an aspect of the present disclosure;

Fig. 3 schematically illustrates a perspective view of an air purification device arranged within an air duct according to an aspect of the present disclosure;

Fig. 4 schematically illustrates a perspective view of an ionizing unit of an air purification device according to an aspect of the present disclosure; Fig. 5 schematically illustrates a perspective view of an air purification device arranged within an air duct according to an aspect of the present disclosure; and,

Fig. 6 schematically illustrates a perspective view of an air purification device according to an aspect of the present disclosure.

DETAILED DESCRIPTION

Herein “flow of air” refers to air that passes through the air purification device in use. The flow of air may be actively generated in that it is driven by a fan or other such air displacement means, or it may be passive in that it is generated by way of the air being directed through the filter of the air purification device while a vehicle comprising such an air purification device is being driven. The flow of air may also be driven by an air conditioning system of a vehicle.

The term “ionizing unit” is used herein to denote a combination of an emitter electrode and a collector electrode.

The term “emitter electrode” may also be denoted “emitter” or “sender electrode”.

The term “collector electrode” may also be denoted “collector”, “receiver electrode” or “receiver”.

The ionizing volume generated on application of a voltage to the emitter may be positive or negative. The voltage applied to the emitter electrode may be any suitable voltage. The voltage applied to the emitter electrode may e.g. be between -12 and 12 kV DC, preferably between -8 and 8 kV DC.

Herein the term “discharge protrusion” refers to a corona discharge protrusion configured to produce an ionizing volume based on a charge. Such a corona discharge protrusion may be any suitable protrusion such as a point, a tip, a carbon brush or the like. Such an ionizing volume may be produced by means of such discharge protrusion where a density of an electrical field is sufficient for such production.

Such discharge protrusions, i.e. corona discharge protrusions, associated with emitter electrode, may be one or more discharge protrusions. Such corona discharge protrusions are herein denoted emitter discharge protrusions. In the case were there are more than one emitter discharge protrusion, e.g. a plurality of emitter discharge protrusions, the plurality of emitter discharge protrusions may be arranged on a single emitter electrode in which case they are electrically connected to one another. Such emitter electrodes may be one or more emitter electrodes. In the case were there are more than one emitter electrode, e.g. a plurality of emitter electrodes, said plurality of emitter electrodes may be electrically separate from one another, but configured to work together to generate an electric field driving the ionizing operation. Each emitter electrode may comprise a plurality of emitter discharge protrusions.

Such discharge protrusions, i.e. corona discharge protrusions, having a different potential than an at least one emitter electrode, may be corona discharge protrusions associated with an at least one collector electrode, and may be one or more discharge protrusions. Such corona discharge protrusions are herein denoted neutralizing discharge protrusions due to their intended purpose. In the case were there are more than one such neutralizing discharge protrusion, e.g. a plurality of neutralizing discharge protrusions associated with an at least one collector electrode, the plurality of neutralizing discharge protrusions may be arranged on a single collector electrode in which case they are electrically connected to one another. Such collector electrodes may be one or more collector electrodes. In the case were there are more than one collector electrode, e.g. a plurality of collector electrodes, said plurality of collector electrodes may be electrically separate from one another, but configured to be operably connected to one or more emitter electrodes for providing a potential difference so as to facilitate generating electric field(s) during ionizing operation. Said one or more neutralizing discharge protrusions associated with said collector electrodes are arranged and configured to, during an ionizing operation where one or more surfaces are charged by means of ions generated by charging said at least one emitter electrode, based charge of said one or more charged surfaces, generate ions with an opposite charge to the ions generated by charging said at least one emitter electrode so as to facilitate neutralizing said one or more charged surfaces within said air duct. One or more of said one more collector electrodes may comprise one or more neutralizing discharge protrusions.

Such discharge protrusions, i.e. corona discharge protrusions, having a different potential than an at least one emitter electrode, may be corona discharge protrusions having a different potential than both emitter electrode and collector electrode, and may be one or more discharge protrusions. Such corona discharge protrusions are herein denoted neutralizing discharge protrusions due to their intended purpose. In the case were there are more than one such neutralizing discharge protrusion, e.g. a plurality of neutralizing discharge protrusions, the plurality of neutralizing discharge protrusions may be arranged on one or more conductive elements having a potential different to the potential of both emitter electrode and collector electrode. Such one or more conductive elements may be connected to a positive voltage or a negative voltage or to ground. Such one or more neutralizing discharge protrusions may be directly or indirectly connected to a positive voltage or a negative voltage or to ground. Said one or more neutralizing discharge protrusions associated having different potential than both emitter electrode and collector electrode are arranged and configured to, during an ionizing operation where one or more surfaces are charged by means of ions generated by charging said at least one emitter electrode, based on charge of said one or more charged surfaces, generate ions with an opposite charge to the ions generated by charging said at least one emitter electrode so as to facilitate neutralizing said one or more charged surfaces within said air duct. According to an aspect of the present disclosure, in order to obtain positive discharge from said one or more neutralizing discharge protrusions, the potential of said one or more neutralizing discharge protrusions is higher than said one or more emitter discharge protrusions, where said one or more emitter discharge protrusions, by means of the at least one emitter electrode, is configured to generate negative ions.

Fig. 1 a-c schematically illustrates a view in the air flow direction of a of an air purification device 100, arranged within an air duct 50, at different stages of an ionizing operation according to an aspect of the present disclosure.

Said air purification device 100 is configured to separate airborne particles from a flow of air in said air duct 50.

The air purification device 100 comprises an ionizing unit II arranged, during an ionizing operation, to produce an ionizing volume for charging airborne particles present in the flow of air.

The ionizing unit II comprises an emitter electrode 10. Said emitter electrode 10 comprises an emitter discharge protrusion 12. Said emitter electrode 10 is configured to be charged for generating ions. In the schematic example in fig. 1 a-c, one emitter electrode 10 having one discharge protrusion 12 is shown. However, said ionizing unit may comprise one or more emitter electrodes 10, where said one or more emitter electrodes 10 may comprise at least one emitter discharge protrusion 12.

The ionizing unit II further comprises collector electrodes 20, here a pair of collector electrodes 20. The respective collector electrode 20 comprises a neutralizing discharge protrusion 22.

According to the schematic example illustrated in fig. 1 a-c, the air purification, the emitter electrode 10 is connected to a negative voltage -HV and the collector electrode 20 is connected to ground G. The air purification device 100 comprises a power supply device, not shown, configured to provide power, via connections to the emitter electrode and collector electrode 20, so as to facilitate charge of said emitter electrode.

The air purification device 100 comprises a filter medium 30 arranged to attract at least a subset of the charged airborne particles. Said filter medium 30 is according to an aspect configured to be arranged downstream of at least said emitter electrode of said ionizing unit II in relation to the flow of air. Said filter medium comprises surfaces S configured to face said emitter electrode 10.

According to an alternative aspect, not shown, said filter medium may be a filter medium comprising a conductive material and being configured to act as collector electrode. According to this alternative aspect, said collector electrode is thus an integrated part of said filter medium. According to this alternative aspect, said at least one neutralizing discharge protrusion is operably connected to said filter medium.

Said air duct 50 is configured allow said flow of air to flow within said air duct 50 towards and passed said ionizing unit II and filter medium 30 of said air purification device 100. Said air duct has inner surfaces S being arranged in connection to and some at least partly facing towards said air purification device 100 when arranged within said air duct 50. According to an aspect of the present disclosure, said surfaces S are at least partly non-conductive surfaces. According to an aspect of the present disclosure, said surfaces S may have no conductivity or low conductivity. According to an aspect of the present disclosure, said surfaces S may be conductive and not connected to any specific potential.

Fig. 1 a schematically illustrates a view in the air flow direction of said air purification device 100, arranged within said air duct 50, at a first stage of an ionizing operation according to an aspect of the present disclosure.

During this first stage of the ionizing operation, said emitter electrode 10 having said emitter discharge protrusion 12 is being charged for generating ions so as to create an ionizing volume V1 for charging airborne particles present in the flow of air. Said ions are generated based on an electrical field created in connection to said emitter discharge protrusion 12. Said electrical field is generated by means of the negative high voltage -HV applied to said emitter electrode 10, providing a potential difference between the grounded G collector electrodes 20. The thus created ionizing volume V1 comprises negative ions -I, i.e. negatively charged ions -I.

During this first stage of the ionizing operation, one or more surfaces S within said air duct 50 are charged by means of a subset of said negative ions -I generated by charging said emitter electrode 10 so that said surfaces S become negatively charged.

Fig. 1 b schematically illustrates a view in the air flow direction of said air purification device 100, arranged within said air duct 50, at a second stage of said ionizing operation according to an aspect of the present disclosure.

During this second stage of the ionizing operation, said electrical field created in connection to said emitter discharge protrusion 12, which is a negative electrical field and thus has the same polarity as the thus negatively charged one or more surfaces S, is supressed.

Further, during this second stage of the ionizing operation, ionising volumes V2, V3 with ions +l with positive charge are generated in connection to said neutralizing discharge protrusions 22 associated with said collector electrodes 20. Said positive ions +l are generated by means of said electrical field thus created based on said negatively charged one or more surfaces S providing a potential difference between said grounded G neutralizing discharge protrusions 22 and said negatively charged one or more surfaces S.

Further, during said second stage of the ionizing operation, said charged one or more surfaces S attract at least a subset of said positive ions +l. Fig. 1c schematically illustrates a view in the air flow direction of said air purification device 100, arranged within said air duct 50, at a third stage of said ionizing operation according to an aspect of the present disclosure.

During this third stage of the ionizing operation, which is a transition from said second stage, said charged one or more surfaces S, having attracted at least a subset of said positive ions +l so that neutralisation of said charged one or more surfaces S is facilitated. As said one or more surfaces S are being at least partly neutralized, the supressed negative electrical field created in connection to said emitter discharge protrusion 12 is re-built so that generation of negative ions in connection to said emitter discharge protrusions 12 is facilitated.

Following this third stage of the ionizing operation, said ionizing operation stabilizes on a given potential of the surroundings, e.g. one or more surfaces S, within said air duct 50, where positive ions +l and negative ions -I, balances each other on said one or more surfaces. Thus, the physics of the problem, i.e. the charged one or more surfaces S of the surrounding within said air duct causing reduced ion density in the ionizing volume produced by means of said ionizing unit II during an ionizing operation, is utilized to achieve an automatic electrical stabilization inside surroundings with surfaces S being at least partly non-conductive, e.g. non-conductive or with low conductivity, or surfaces not connected to any specific potential.

Fig. 2a schematically illustrates a view in the air flow direction of an air purification device 100 according to an aspect of the present disclosure; and fig. 2b schematically illustrates a cross-sectional view of the air purification device 100 in fig. 2a according to an aspect of the present disclosure.

Said air purification device 100 is configured to separate airborne particles from a flow of air A in said air duct 50. The air purification device 100 comprises an ionizing unit II arranged, during an ionizing operation, to produce an ionizing volume for charging airborne particles present in the flow of air A.

The ionizing unit II comprises an emitter electrode 10. Said emitter electrode 10 comprises a plurality of emitter discharge protrusions 12. Said emitter electrode 10 has according to the embodiment schematically illustrated in fig. 2a an elongated configuration, provided as an elongated member such as a bar or the like. Said plurality of emitter discharge protrusions 12 are, according to the embodiment schematically illustrated in fig. 2a, configured to be distributed along said elongated emitter electrode 10. Said plurality of emitter discharge protrusions 12 are, according to the embodiment schematically illustrated in fig. 2a, configured to point away from said filter medium 30. Said emitter electrode 10 is configured to be charged for generating ions.

The ionizing unit II further comprises collector electrodes 20, here a pair of collector electrodes 20. The respective collector electrode 20 comprises neutralizing discharge protrusion 22, here a pair of neutralizing discharge protrusions 22. The respective collector electrode 20 has according to the embodiment schematically illustrated in fig. 2a an elongated configuration, provided as an elongated member such as a bar or the like.

According to the schematic example illustrated in fig. 2a-b the one of said elongated collector electrodes 20 is arranged at one side at a distance from said elongated emitter electrode 10 and configured to run essentially parallel to said elongated emitter electrode 10, and the other of said elongated collector electrodes 20 is arranged at the opposite side at a distance from said elongated emitter electrode 10 and configured to run essentially parallel to said elongated emitter electrode 10.

The air purification device 100 comprises a power supply device P configured to provide power, via connections C1 , C2 to the emitter electrode and collector electrode 20, so as to facilitate charge of said emitter electrode 10. The air purification device 100 comprises a first connector arrangement C1 connecting the power supply device P to the emitter electrode 10, and a second connector arrangement C2 connecting the power supply device P to said collector electrodes 20. According to an aspect of the present disclosure, said power supply device P comprises a power operation unit P1 .

Said emitter electrode 10 may be connected to a negative voltage and said at collector electrodes 20 to ground or a positive voltage, or, alternatively, said emitter electrode 10 may be connected to a positive voltage and said collector electrodes 10 to ground or a negative voltage. According to a preferred embodiment, the emitter electrode 10 is connected to a negative high voltage and the collector electrode 20 is connected to ground.

According to an aspect of the present disclosure, said ionizing unit II comprises a support arrangement 40 for supporting said at least one emitter electrode 10 and said at least one collector electrode 20. Such a support arrangement may have any suitable shape and configuration. According to an aspect of the present disclosure, said support arrangement 40 is configured to be adapted to the shape of the air duct 50 so as to facilitate assembly of said air purification device 100 within said air duct. According to the schematic example illustrated in fig. 2a-b, said support arrangement 40 has a frame like configuration, here shaped as a rectangular frame member, having a first side 42, a second side 44 opposite to said first side 42, a third side 46 orthogonal to said first and second sides 42, 44 and a fourth side 48 opposite to said third side 46, said sides 42, 44, 46, 48 forming said frame shaped support arrangement 40.

According to the schematic example illustrated in fig. 2a-b, said emitter electrode 10 is configured to be centrally connected at its respective end to the frame like support arrangement 40 between said first side 42 and opposite second side 44 of said frame like support arrangement 40, wherein one of said collector electrodes 20 being configured to run along the third side 46 and the other of said collector electrodes 20 being configured to run along the fourth side 48, said collector electrodes running essentially parallel at each side of said emitter electrode 10.

The air purification device 100 comprises a filter medium 30 arranged to attract at least a subset of the charged airborne particles. Said filter medium 30 is according to an aspect configured to be arranged downstream of at least said emitter electrode of said ionizing unit in relation to the flow of air. Said filter medium comprises surfaces S configured to face said emitter electrode 10.

The filter medium has a first side 30a configured to face towards the flow of air A and an opposite second side 30b. Said first side 30a of said filter medium 30 may be denoted upstream side and said second side 30b of said filter medium 30 may be denoted downstream side. Said first side 30a of said filter medium 30 has a surface S or surfaces S. Said upstream side 30a of said filter medium 30 is, according to the embodiment illustrated in fig. 2b, configured to face towards said ionizing unit II comprising said emitter electrode 10 and collector electrodes 20.

According to an aspect of the present disclosure, as illustrated in fig. 2b, the filter medium 30 has a crimped configuration, i.e. a wavy configuration.

Said plurality of emitter discharge protrusions 12 are, according to the embodiment schematically illustrated in fig. 2a, configured to point away from said filter medium 30.

Said air duct 50 is configured to allow said flow of air A to flow within said air duct 50 towards and passed said ionizing unit II and filter medium 30 of said air purification device 100. Said air duct has inner surfaces S being arranged in connection to and some at least partly facing towards said air purification device 100 when arranged within said air duct 50. According to an aspect of the present disclosure, said surfaces S are at least partly non-conductive surfaces. According to an aspect of the present disclosure, said surfaces S may have no conductivity or low conductivity. According to an aspect of the present disclosure, said surfaces S are conductive and not connected to any specific potential. Said neutralizing discharge protrusions 22 are, according to the embodiment schematically illustrated in fig. 2a, configured to point away from said filter medium 30.

As described above with reference to fig. 1a-c, during an ionizing operation, said emitter electrode 10 having said emitter discharge protrusions 12 is being charged for generating an ionizing volume for charging airborne particles present in the flow of air A. Said ions are generated based on an electrical field created in connection to said emitter discharge protrusion 12. Said electrical field is generated by means of high voltage applied to said emitter electrode 10 by means of said power supply device P, providing a potential difference between the grounded collector electrodes 20. One or more surfaces S within said air duct 50 may hereby be charged by means of a subset of said ions generated by charging said emitter electrode 10 so that said surfaces S become charged.

Said neutralizing discharge protrusions 22 associated with said at least one collector electrode 20 are arranged such that, during said ionizing operation, when one or more surfaces S within said air duct 50 are charged by means of at least a subset of said ions generated by charging said at least one emitter electrode 10, a potential difference between said one or more charged surfaces S and said neutralizing discharge protrusions 22 is created. This potential difference generates oppositely charged ions in connection to said neutralizing discharge protrusions 22 based on said created potential difference.

Said one or more surfaces S charged, e.g. negatively charged, by means of said subset of ions generated by charging, e.g. negatively charging, said at least one emitter electrode 10, attract ions of said oppositely charged ions generated in connection to said neutralizing discharge protrusion 22, wherein at least partly neutralization of the charge of said one or more charged surfaces S is facilitated. Said neutralizing discharge protrusions 22 of said at collector electrodes 20 are, in the exemplified embodiment illustrated in e.g. fig. 2a-b, configured to be arranged in connection to surfaces S of said air duct 50 so as to facilitate generating, based on the charge of said surfaces S, a proper amount of oppositely charged ions to be attracted to said one or more charged surfaces S for facilitating neutralizing said one or more surfaces S within said air duct 50.

According to an aspect of the present disclosure, as illustrated in exemplified embodiment in e.g. fig. 2a-b, the number of emitter discharge protrusions 12 of said emitter electrode 10 is larger than the number of neutralizing discharge protrusions 22 of said one or more neutralizing discharge protrusions 22 associated with said at least one collector electrode 20. Hereby avoidance of neutralization of already charged particles in the flow of air A by means of oppositely charged ions is facilitated due to the thus reduced number of neutralizing discharge protrusions 22 relative to the number of emitter discharge protrusions 12. Hereby avoidance of oppositely charging particles in the flow of air A by means of oppositely charged ions is facilitated due to the thus reduced number of neutralizing discharge protrusions 22 relative to the number of emitter discharge protrusions 12.

According to an aspect of the air purification device 100, said power supply device P comprises an electronic control unit 200. According to an aspect of the air purification device 100, said power operation unit P1 of said power supply device P comprises said electronic control unit 200. Said electronic control unit 200 is according to an aspect of the present disclosure configured to control the ionizing operation of said ionizing unit II of said air purification device 100.

According to an aspect of the air purification device 100, said power supply device P comprises a current regulator CR configured to operate said ionizing unit II by means of an essentially constant current. According to an aspect of the air purification device 100, said power operation unit P1 of said power supply device P comprises said current regulator CR. Said power supply device, e.g. said current generator of said power supply device, may, during an ionization operation, need to make certain adaption of the voltage in order to keep said essentially constant current.

Said electronic control unit 200 is according to an aspect an integrated part of said current regulator. Said electronic control unit 200 is according to an aspect operably connected to said current regulator CR.

By thus operating said ionizing unit II by means of controlling said current regulator CR at an essentially constant current the ionization operation may be performed without the efficiency of the ionization operation being negatively affected.

Fig. 3 schematically illustrates a perspective view of an air purification device 100 arranged within an air duct 50 according to an aspect of the present disclosure. The air purification device 100 illustrated in fig. 3 differs from the air purification device 100 in fig. 2a-b in that the power supply device is not shown and that the there is no support arrangement according to fig. 2a-b shown.

Fig. 4 schematically illustrates a perspective view of an ionizing unit II of an air purification device according to an aspect of the present disclosure. The ionizing unit essentially corresponds to the ionizing unit of the air purification device 100 illustrated in fig. 2a-b.

Fig. 5 schematically illustrates a perspective view of an air purification device arranged within an air duct according to an aspect of the present disclosure; and. The air purification device 100 illustrated in fig. 5 differs from the air purification device 100 in fig. 2a-b in that the power supply device is not shown.

Fig. 6 schematically illustrates a perspective view of an air purification device 100 according to an aspect of the present disclosure. The air purification device 100 differs from the air purification device 100 illustrated e.g. in fig. 2a-b in that neutralizing discharge protrusions 22 are connected to said support arrangement 40. In the embodiment according to fig. 6, the collector electrodes 20 are comprised in said support arrangement 40. Thus, said discharge protrusions 22 are operably connected to said support arrangement integrated collector electrodes 20 so that they have the same potential. The neutralizing discharge protrusions 22 as illustrated in fig.

6 are arranged closer to surfaces S of said air duct 50, compared to e.g. the neutralizing discharge protrusions 22 of the air purification device 100 illustrated in fig. 2a-b.

The foregoing description of the preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications suited to the particular use contemplated.