Filter unit for air purification device and air purification device

Abstract

The present invention relates to a filter unit for an air purification device, wherein the filter unit (1) comprises an odor filter (2) for neutralizing odors, the odor filter representing a device for generating plasma, characterized in that the odor filter (2) comprises at least one air-permeable high-voltage electrode (20) and at least one air-permeable counter electrode (21), each of which is formed by a planar element, and the at least one air-permeable high-voltage electrode (20) and the at least one air-permeable counter electrode (21) are arranged one after the other along the flow direction. In addition, an air purification device having such a filter unit (1) is described.

Description

Technical Field

[0001] The invention relates to a filter unit for an air purification device and an air purification device. Background Art

[0002] In particular, for range hoods in recirculating air operation, the filter efficiency of the installed filter medium is decisively responsible for the extent to which the smoke air generated during the cooking process and contaminated by very fine particles and cooking odors is filtered. This is important because the smoke air sucked in by the range hood is not transported to the outside to the open air, but circulated in a closed room (living room, kitchen, etc.). If the filter medium installed in the range hood has a low or unsatisfactory filter efficiency, the cooking vapor remains in the closed living room air, which contains aerosols and volatile organic compounds that are unpleasant to the sense of smell. Against this background, high requirements are placed on the filter medium installed in the range hood in terms of filter efficiency. The object of the present invention is to keep the air pure not only in the living room but also in the passenger compartment in the automotive field.

[0003] In range hoods, mechanical filters are used to filter aerosols (solid and liquid particles). The mechanical filters are expanded metal filters, perforated plate filters, baffle filters, nonwovens (fibrous materials), edge suction filters, sintered plastics and other porous media, etc. All of these filter media mentioned filter according to mechanical separation mechanisms, such as diffusion effect, barrier effect and decisively according to inertia effect. During separation according to inertia effect, the particles cannot follow the flow lines of the gas (air) around the individual filter fibers, expanded metal mesh layers, porous media, etc. due to their inertia and thus collide with them. Considering the odor filtration of cooking odors and other organically volatile compounds VOC's, activated carbon filters and zeolite filters in the form of filter cartridges (also called circulating air filters for range hoods in practice) are mainly used for circulating air operation. These filters are usually installed directly after the grease filter (or before the ventilation device) or after the ventilation device in the blow-out area of ​​the range hood. In addition to these mentioned adsorption devices, plasma filters are also used in practice as self-sufficient systems for odor neutralization. These systems, which are usually conceived as purchased parts, are installed as pipe heads on the exhaust pipe of the range hood (after the ventilation device). Usually, these plasma filters are designed in a cylindrical shape for application to the air exhaust pipe of the ventilation device housing.

[0004] The fact that the grease filter and the odor filter or the system for odor neutralization (plasma filter) are spatially separated from one another in the air flow direction is important for these described systems. Another disadvantage of currently available plasma filters is the fact that they require considerable space / installation space and cannot be combined with every range hood. In addition, both the adsorber (activated carbon filter, zeolite filter) and the plasma filter are not normally purifiable systems. Regenerable systems are available separately on the market. The service life of these odor filters or systems for odor neutralization (plasma filters) is lower than that of commercially available range hoods. Summary of the invention

[0005] It is therefore an object of the present invention to provide a solution by means of which a sufficient filter efficiency can be reliably ensured with a small space requirement.

[0006] According to a first aspect, the invention therefore relates to a filter unit for an air purification device, wherein the filter unit comprises an odor filter for odor neutralization, the odor filter representing a device for generating plasma. The filter unit is characterized in that the odor filter comprises at least one air-permeable high-voltage electrode and at least one air-permeable counter-electrode, each of which forms a free-form surface, and the at least one air-permeable high-voltage electrode and the at least one air-permeable counter-electrode are arranged one behind the other in the flow direction.

[0007] The filter unit is also referred to below as a filter module or filter box. The filter unit can be used in the air cleaning device, which can be a range hood or range hood or other smoke extraction device or an air cleaner for indoor use or for the passenger compartment in the automotive field.

[0008] The odor filter for odor neutralization is also referred to below as plasma filter, plasma unit, plasma module or plasma segment. The plasma filter is used to remove volatile organic compounds, VOC's for short, from the inhaled air flow.

[0009] According to the invention, the plasma filter has at least one air-permeable high-voltage electrode and at least one air-permeable counter-electrode. The electrodes of the plasma filter are respectively planar elements. The at least one air-permeable high-voltage electrode and the at least one air-permeable counter-electrode are arranged one behind the other along the flow direction. The throughflow direction, along which the sucked air flows through the filter unit, is referred to as the flow direction. The high-voltage electrode and the counter-electrode, that is to say the planar element, can be in the form of a flat surface. However, as an alternative, the planar element can also have, for example, an arched, corrugated or pleated shape. The electrodes of the plasma filter are preferably parallel to each other. For electrodes representing planar elements that differ from a flat surface, the high-voltage electrode and the counter-electrode have the same shape, that is, their curvature, the curvature of the individual corrugations or the slope of the tips of the pleats are the same. This ensures that the spacing between the electrodes is the same within the surface of the electrodes. When the filter unit is in operation, plasma is generated between the high-voltage electrode and the counter-electrode.

[0010] Regarding the voltage form applied to the electrodes of the odor filter, the high voltage electrode for the air permeability can be either a U 峰值 >=500V and a pulsed voltage with a period duration T<=1s. The pulsed voltage can be of positive or negative voltage type. As an alternative, a voltage having, for example, U 有效值 An alternating voltage of >=500V and a cycle duration T>=1s is possible. Different voltage forms are possible for the alternating voltage and the pulse-excited voltage. Here, for example, a sinusoidal, rectangular, triangular or sawtooth voltage form is used. The gas-permeable counter electrode is connected to a counter potential so that a variable voltage difference ΔU between the high-voltage electrode and the counter electrode can be ensured. As an alternative, the gas-permeable counter electrode can be grounded. For this application, the gas-permeable counter electrode is electrically connected to the ground wire PE (protective earth).

[0011] Since the electrodes each represent a planar element, a plasma wall is formed in the distance between the electrodes, through which plasma wall the air to be purified passes and is purified there.

[0012] The high-voltage electrode and the counter-electrode are permeable to air and are arranged one after the other in the flow direction, which allows a number of advantages to be achieved. In particular, a high efficiency can be achieved in terms of odor reduction. This is due to the fact that during operation, a plasma wall is formed by means of the at least one permeable high-voltage electrode and the at least one permeable counter-electrode, through which the air carrying the odor molecules flows. When the odor molecules in the air flow through this ionized region, which is called the "plasma wall", a sufficient chemical reaction of these odor molecules mentioned with the active species occurs. In other words, a sufficient mixing of the odor molecules with other reactive oxygen species (ROS) and reactive nitrogen species (RNS) takes place.

[0013] According to a preferred embodiment, the filter unit has an electrostatic filter, which has an ionization unit and a separation unit. The electrostatic filter is used to filter particles, so-called aerosols, such as grease, water or dirt from the air. The electrostatic filter is also called an electrostatic particle filter, a particle filter or a grease filter. The electrostatic filter has an ionization unit, which is also called an ionization stage or an ionization segment. In the ionization unit, the particles are charged, for example, by means of a so-called corona discharge. For this purpose, preferably at least one discharge electrode and at least one counter electrode are provided in the ionization unit. It is particularly preferred that a discharge electrode is provided between the two counter electrodes of the ionization unit. The particles that are to be separated in the electrostatic filter have no charge in their original state or have a charge that is insufficient for effective electrostatic separation. The particle charging of each individual particle is generated by the ionization unit, preferably until its maximum saturation charge q s The discharge electrode, which can represent a wire, for example, is preferably exposed to a high voltage. The voltage can be either a positive voltage or a negative voltage. Positive voltage is preferably used due to the lower ozone emissions. The voltage can be, for example, a direct current voltage with U>=1 kV DC or, as an alternative, a voltage with U 峰值 >=1kV and period duration T<=1s pulse excitation voltage. The pulse excitation voltage can not only be a sinusoidal, rectangular, triangular or sawtooth voltage form. The counter electrode of the ionization unit is preferably electrically connected to the counter potential. According to one embodiment, the counter electrode of the ionization unit is connected to the ground line PE (protective earth).

[0014] As an alternative to the described ionization units for charging the particles, which operate according to the principle of corona discharge, it is also possible to use ionization units in which other mechanisms for charging the particles are used. This includes ionization units in which the particle charging is carried out by means of dielectric barrier discharge (DBE) or photoelectric radiation.

[0015] The particles charged by the ionization unit flow through the separation unit, which is arranged behind the ionization unit in the flow direction and can also be called a separation section. In the separation unit, an electric field relative to each other is built up by at least two deposition electrodes under high voltage. The air flowing out of the ionization unit and carrying the charged particles flows into the separation unit. Due to the electric field built up there between the deposition electrodes, the particles are separated on the deposition electrodes and thus filtered out of the air.

[0016] The filter unit also has an electrostatic filter in addition to the odor filter, so that this embodiment unifies the functions of the particle filter and the odor filter in one system, that is, in the filter unit. By this embodiment, every impurity is removed from the air.

[0017] According to one embodiment, the separation unit of the electrostatic filter has at least one conductive deposition electrode and at least one grounded deposition electrode. The deposition electrodes are preferably arranged alternately in the separation unit. According to one embodiment, the deposition electrodes of the separation unit can be airtight plates. In this case, the separation unit can also be called a plate separator. During filtering operation, an electric field strength E (= voltage / plate spacing) is formed between the alternately arranged plates, which in turn applies an external force to the corresponding charged particles. As a result, the charged particles are turned in the direction of the deposition electrodes and separated on these deposition electrodes. The particles accumulate on the surface of the plates. The plates are preferably arranged parallel to the flow direction of the air through the filter unit.

[0018] According to an alternative embodiment, the deposition electrode represents a gas-permeable electrode. In this case, the particle separation is carried out on an electrically conductive gas-permeable deposition electrode and a grounded gas-permeable deposition electrode which are also arranged alternately. The deposition electrode is preferably designed as a planar element, for example as a flat planar element. In the case of a gas-permeable deposition electrode, the deposition electrode is preferably arranged in a direction which is inclined relative to the flow direction and preferably perpendicular to the flow direction.

[0019] According to a preferred embodiment, the odor filter of the filter unit is arranged in the flow direction after the electrostatic filter. This ensures that particles, in particular aerosols, are first removed from the polluted air, in particular cooking fumes, and that odors contained in the air, in particular cooking smells, are subsequently neutralized. As an alternative, the odor filter can also be arranged spatially between the segments of the electrostatic filter, that is, between the ionization segment and the separation segment. In another alternative, the odor filter is arranged in the flow direction before the electrostatic filter, in particular the ionization unit.

[0020] According to one embodiment, the odor filter and the electrostatic filter are received in a common housing. The housing can also be referred to as a frame. Preferably, the segments of the filter unit, in particular the ionization segment, the separation segment and the odor filter are releasably received in the housing. Here, all three segments can be taken out from the housing one by one. However, it is also possible that the segments of the electrostatic filter are connected to each other and can only be taken out from the housing together, while the odor filter can be taken out from the housing separately from the electrostatic filter. The housing can be fixedly fixed in the air purification device for the segments that can be releasably received. However, the segments of the filter unit can also be fixedly connected in the housing. In this case, the housing is preferably releasably held in the air purification device. Thus, the odor filter and the electrostatic filter can be taken out from the air purification device together. However, in this case, the housing can also be fixedly held in the air purification device. Each segment optionally has an independent filter housing. These filter housings are then connected to each other in a form-locked, force-locked or material-locked manner in this case.

[0021] For example, for maintenance or cleaning purposes, it may be necessary to remove one or more segments of the filter unit. For the form-locking and force-locking connections between the individual filter housings, the segments can be disassembled for maintenance and cleaning purposes for the user.

[0022] According to a preferred embodiment, the electrodes of the odor filter are arranged in a direction inclined relative to the main flow direction. Preferably, the electrodes of the odor filter are perpendicular to the flow direction. By such an orientation of the electrodes, on the one hand, the area of ​​the plasma wall generated by the electrodes can be maximized, without the depth of the filter unit, that is, its size in the flow direction, having to be increased. On the other hand, with such an orientation, it is possible to ensure that the air-permeable electrodes are passed through by the air to be purified and that the air is mixed, thereby ensuring effective removal of odor molecules and other VOC's with less energy input.

[0023] Preferably, at least one of the electrodes of the odor filter has an insulating coating on at least one surface.

[0024] The working mechanism of the odor filter for eliminating odors is a dielectric barrier discharge (DBE) solution according to the present invention. The insulating coating provided on at least one electrode of the odor filter can thus serve as a dielectric between the high-voltage electrode and the counter electrode.

[0025] The capacitive odor filter device is composed of at least two electrodes (high voltage electrode, counter electrode) with different potentials relative to each other and at least one dielectric between the two electrodes. The capacitive odor filter device causes a displacement current I when using a voltage difference ΔU between the two electrodes that changes over time, and the displacement current in turn causes ionization of the air through an ionization process. Through this ionization process in the ionization region (plasma region), active species, so-called reactive oxygen species (ROS) and reactive nitrogen species (RNS) are formed through impact ionization processes. These active species are energetically highly active molecules that, in particular, combine with unpleasant odor molecules and other volatile organic compounds (VOC's), whereby these unpleasant odor molecules are chemically converted into other compounds. Therefore, odor reduction or even complete odor elimination occurs through the chemical process between the odor molecules and the active species.

[0026] Based on this process / this principle of action, porous electrodes are used in the odor filter, that is, in the section for odor neutralization, which cause ionization of the air between the electrodes according to the principle of dielectric barrier discharge. This ionization of the air (plasma formation) in the ionization area causes the removal / neutralization of odor molecules and other volatile compounds (VOC's) that are olfactory unpleasant.

[0027] For this reason, at least one of the two electrodes of the odor filter has a surface-electrical insulation (dielectric) to prevent electrical spark discharges and short circuits between the two electrodes and to ensure the function of the plasma cell. Ideally, the gas-permeable high-voltage electrode is electrically insulating. As an alternative, the gas-permeable counter electrode can be electrically insulating or all electrodes have electrical insulation on their surfaces.

[0028] Possible coating methods for electrically insulating the electrodes of the odor filter include, for example, functional powder and ceramic coatings of the electrodes, fluidized bed coating methods, sol-gel methods, dip coating, glazing, painting or gluing.

[0029] The electrodes of the odor filter are preferably arranged alternately with each other. This means that each air-permeable high-voltage electrode is arranged relative to an air-permeable counter-electrode. The first and last electrodes along the flow direction can be either air-permeable counter-electrodes or air-permeable high-voltage electrodes.

[0030] According to one embodiment, at least one high-voltage electrode and / or at least one counter-electrode is of multilayer construction. In this embodiment, the respective electrode is composed of a plurality of gas-permeable layers (n>=1).

[0031] According to the invention, the electrodes of the odor filter are air-permeable. According to one embodiment, the at least one high-voltage electrode and / or the at least one counter-electrode are made of an air-permeable material. In this embodiment, the electrodes are also referred to as porous electrodes. The electrodes can all be made of the same air-permeable material. However, it is also within the scope of the invention that different electrodes are made of different materials. The advantage of using an air-permeable material for the electrodes of the odor filter is that, on the one hand, the manufacture of the odor filter becomes easier, because the required air permeability is produced by the material itself.

[0032] According to another embodiment, the electrodes of the odor filter are made of an airtight material having at least one air through hole. It is also possible that only some of the electrodes, such as only the high-voltage electrode or only the counter electrode, are made of such a material and the respective other electrodes are made of an airtight material.

[0033] Independently of whether the electrodes of the odor filter are made of an air-permeable material or of an air-impermeable material with air-through holes, the material of the electrodes is selected such that it is electrically conductive or antistatic.

[0034] The electrodes of the odor filter can be, for example, perforated sheets, such as perforated plates, welded grids, woven wire grids, expanded metal meshes, sintered materials and foam materials.

[0035] The electrodes of the odor filter are preferably arranged offset relative to one another in order to ensure an optimal ionization of the air flowing through and laden with odor molecules, which in turn leads to an optimal neutralization of the odor substances / odor molecules. An offset arrangement is an arrangement in which an opening in one electrode does not overlap an opening in an adjacent electrode.

[0036] According to one embodiment, the high-voltage electrode and the counter-electrode are arranged relative to one another in such a way that their structure is in the plane of the respective electrode in a manner twisted about an axis. This means that the individual electrodes are offset in the plane of the respective electrode in the installed state about a rotation axis perpendicular to the plane of the electrode by an angle of 0 to 360°.

[0037] According to a preferred embodiment, a high voltage is applied to the electrodes of the odor filter, and the high voltage changes over time. The high voltage can be, for example, an alternating voltage or a pulsed voltage. According to an embodiment, the odor filter therefore has a high voltage converter, through which a high voltage that changes over time can be generated for the electrodes of the odor filter, especially the high voltage electrodes of the odor filter. The high voltage converter is used to generate or produce the necessary high voltage. The high voltage converter can also be called a high voltage generator or a high voltage power supply part. This high voltage converter supplies high voltage or electrical energy to the electrodes of the odor filter, especially at least one high voltage electrode and at least one counter electrode, through a connecting line on the secondary side. On the primary side, the voltage supply of the high voltage converter is carried out through a connector or connecting line for a lower voltage. This lower voltage on the primary side of the high voltage converter can be a direct voltage of ≤1500 VDC or an alternating voltage of ≤1000 V AC.

[0038] According to a further aspect, the invention relates to an air cleaning device having at least one filter unit according to the invention.

[0039] The advantages and features described with regard to the filter unit apply correspondingly—as far as applicable—to the air cleaning device and vice versa.

[0040] The air cleaning device can be, for example, an air purifier for filtering indoor air, a device for filtering the air sucked in the passenger compartment in the automotive field, or a range hood for a kitchen. The air cleaning device can have a plurality of filter units according to the present invention according to the present invention. The at least one filter unit is preferably arranged on the intake side of the air cleaning device. However, it is also within the scope of the present invention to provide at least one filter unit on the air discharge side of the air cleaning device as a supplement or alternative.

[0041] According to a preferred embodiment, the air cleaning device represents an extractor hood and the at least one filter unit is arranged upstream of a blower of the extractor hood.

[0042] With regard to the range hood, the filter unit according to the invention, which can also be referred to as an ionizing filter unit / filter cartridge, is preferably arranged in the air intake region of the range hood in order to prevent the components of the range hood located therebelow from being soiled by cooking fumes / aerosols / dirt. However, such an ionizing filter unit can also optionally be arranged in the air outlet region of the range hood or between the inlet region and the outlet region of the range hood along the air flow guidance direction. The geometric dimensions (length, width and height) of such an ionizing filter module vary depending on the installation position or type and geometry of the range hood. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be described in detail again with reference to the accompanying drawings.

[0044] Figure 1 A schematic perspective view of an embodiment of the filter unit according to the invention is shown;

[0045] Figure 2 A schematic perspective view of another embodiment of the filter unit according to the invention is shown;

[0046] Figure 3 shows a schematic, three-dimensional exploded view of an embodiment of the filter unit according to the invention;

[0047] Figure 4 A schematic, three-dimensional exploded view of another embodiment of the filter unit according to the invention is shown;

[0048] Figure 5 A schematic block diagram shows an embodiment of an odor filter of the filter unit according to the invention;

[0049] Figure 6 A schematic perspective view of an embodiment of an odor filter of the filter unit according to the invention is shown;

[0050] Figure 7 A schematic detailed view of another embodiment of an odor filter of the filter unit according to the invention is shown;

[0051] Figure 8a , 8b 8c shows a schematic diagram of an embodiment of the electrode geometry of the odor filter of the filter unit according to the present invention;

[0052] Figure 9a and 9b A schematic diagram showing another embodiment of the electrode geometry of the odor filter of the filter unit according to the invention;

[0053] Fig.10a , 10b 10c and 10c show schematic diagrams of another embodiment of the electrode geometry of the odor filter of the filter unit according to the present invention;

[0054] Figures 11a to 11d A schematic diagram showing a possible voltage profile for a voltage of an odor filter of the filter unit according to the invention;

[0055] Fig.12a and 12b Schematic diagrams showing different geometric shapes of electrodes of the odor filter; and

[0056] Fig.13 A schematic block diagram of an embodiment of a high-voltage converter is shown. DETAILED DESCRIPTION

[0057] exist Figure 1 A schematic perspective view of a first embodiment of the filter unit 1 according to the invention is shown in . The filter unit represents an ionized filter unit 1 and is also referred to as a filter module / filter box. The filter unit 1 consists of an odor filter 2, also referred to as a plasma filter, and an electrostatic filter 3. The electrostatic filter 3 has the function of filtering solid and liquid particles (aerosols) out of the air flow. The plasma filter 2 arranged at the rear serves to neutralize cooking odors and other VOC's from the air flow. The ionized filter module 1 mentioned is based on Figure 1 The filter unit 1 is composed of three sections. In particular, the filter unit 1 is composed of a section for particle charging, also called ionization unit 30, a section for particle separation, also called separation unit 31, and the section for odor neutralization, also called odor filter 2 or plasma filter. All three sections 30, 31, 2 are arranged spatially one behind the other along the air flow direction indicated by block arrows in the figure and represent a self-sufficient filter system to the outside.

[0058] Regarding the orientation of the individual segments 30, 31, 2 along the air flow direction, Figure 1 The segment 30 for particle charging is arranged before the segment 31 for particle separation. The segment 2 for odor neutralization by means of plasma preferably forms the last air treatment stage. This ensures that aerosols are first filtered out of the cooking fumes and the cooking odors are subsequently neutralized. As an alternative, the segment for odor neutralization can also be arranged spatially between two other segments or first also before the segment for particle charging.

[0059] exist Figure 2Another embodiment of the filter unit 1 is shown in FIG. Figure 1 The embodiments shown in differ only in the depth of the individual segments, ie their extension in the flow direction.

[0060] exist Figure 3 FIG. 1 shows a single part of each segment 2, 30, 31 of an embodiment of the filter unit 1. Figure 3 In an embodiment of the invention, an electrostatic filter 3 is used for particle filtration, which consists of the segment 30 for particle charging and the segment 31 for particle separation. The particle charging is carried out in the ionization unit 30 by means of corona discharge. For this purpose, a discharge electrode 300 is arranged between two counter electrodes 301. In the ionization unit 30, the particles (solid and liquid) in the air are charged by means of corona discharge. In the ionization unit 30, the particle charging of each individual particle is achieved, preferably up to its maximum saturation charge qs.

[0061] The discharge electrode 300 is at a high voltage. Both positive and negative voltages can be used for the voltage. Positive voltages are preferably used due to lower ozone emissions. Both direct current voltages with U>=1 kV DC (direct current) (see Fig.11a ) or as an alternative can use a 峰值 >=1kV(See Fig.11b ) and a pulsed voltage with a period duration T <= 1s. The pulsed voltage can be not only a sinusoidal, rectangular, triangular or sawtooth voltage. The grounded counter electrode 301 is electrically connected to the counter potential, and in this embodiment is electrically connected to the ground wire PE (protective earth). As an alternative, for the ionization unit 30 for particle charging, in addition to the explained principle of corona discharge, other mechanisms for particle charging can also be used. This includes particle charging by means of dielectric barrier discharge (DBE) and the photoelectric radiation.

[0062] Then, the charged particles flow through the separation unit 31. The separation unit 31 is operated in accordance with Figure 3 In the embodiment of the present invention, the plate separator is formed. Figure 4 In an embodiment of , the separation unit 31 is alternatively constructed with a gas-permeable separation medium in the form of gas-permeable electrodes 312, 313. Both options are possible and can be used in an ionizing filter unit 1 for particle separation, depending on the intended use.

[0063] The plate separator is composed of at least one conductive plate-shaped deposition electrode plate 30 and at least one grounded plate-shaped deposition electrode plate 311, which are arranged alternately. During filtering operation, an electric field strength E (= voltage / plate spacing) is formed between the alternately arranged plates 310, 311, which in turn applies an external force to the corresponding charged particles. As a result, the charged particles are turned in the direction of the deposition electrodes 310, 311 and separated on these deposition electrodes. The particles accumulate on the surfaces of the plates 310, 311.

[0064] In the case of a permeable separation medium (see 4), the particle separation is carried out on conductive, permeable deposition electrodes 312 and grounded, permeable deposition electrodes 313, which are also arranged alternately. The permeable deposition electrodes 312, 313 shown can in principle be any permeable material / medium. As examples, welded grids, wire cloth, fiber materials, perforated plates, drawn metal meshes, sintered plastics and foam materials or similar permeable media are considered here. If porous plastic media are used, these porous plastic media must be conductive in terms of their special properties in order to be able to build up an electric field between the individual layers.

[0065] Regarding the type of voltage, a positive or negative voltage can be used for the conductive deposition electrode plate 30 or the conductive gas-permeable deposition electrode 30. Regarding the voltage form, not only a direct voltage with U>=1 kV DC (see Fig.11a ) or as an alternative can use a 峰值 >=1kV(See Fig.11b ) and a pulse-excited voltage with a period duration T <= 1s. The pulse-excited voltage can be not only a sinusoidal, rectangular, triangular or sawtooth voltage. The grounded deposition electrode plate 311 or the grounded gas-permeable deposition electrode 313 is electrically connected to the counter potential, the ground wire connector PE (protective earth).

[0066] according to Figure 3 and Figure 4 The plasma filter 2 is composed of at least one gas-permeable high-voltage electrode 20 (n>=1) and at least one gas-permeable counter electrode 21 (n>=1). Figure 3 and 4 The porous electrodes 20, 21 shown can in principle be any material / medium that is gas-permeable and electrically conductive or antistatic. Perforated sheets, such as perforated plates, welded grids, woven wire grids, expanded metal meshes, sintered materials and foam materials are considered here as examples.

[0067] For a better understanding, such a geometry of the electrodes of the odor filter 2 is partially shown in FIGS. 8 to 10 . Figure 8a The gas permeable counter electrode 21 is formed by Figure 8b The air permeable high voltage electrode 20 is formed by a woven wire grid as shown in FIG. Figure 8a In the embodiment of Figure 8c The welded grid is formed by the welded grid shown in FIG. The welded grid is electrically insulating. Figure 9a In the embodiment, the gas permeable counter electrode 21 and the gas permeable high voltage electrode 20 are respectively Figure 9b The perforated plate forming the gas-permeable high-voltage electrode 20 is preferably electrically insulating. Fig.10a The permeable counter electrode 21 and the permeable high voltage electrode 20 are respectively formed by drawing metal mesh. The drawn metal mesh forming the permeable counter electrode 21 is Fig.10b As shown in FIG. 1 , the drawn metal mesh forming the gas-permeable high-voltage electrode 20 is Fig.10c and are electrically isolated.

[0068] If a plastic medium is used as an air-permeable material for the electrodes 20, 21 of the odor filter 2, at least one of the electrodes must be electrically conductive due to its special properties or by virtue of a surface resistance R <= 10 11 The ohm is antistatic so that when a voltage difference ΔU is applied between electrodes 20 , 21 an electric field can be built up and ionization can take place.

[0069] exist Fig.12a and 12b Another embodiment of the geometry of the electrodes of the odor filter is shown in FIG. Fig.12a Each electrode 20, 21 is pleated. Figure 12b Each electrode 20, 21 is formed in a corrugated shape. Figure 12b The spacing between the electrodes 20, 21 varies, but preferably, the spacing is the same over the surface of the electrodes.

[0070] exist Figure 5 The structure of the odor filter is schematically shown in a block diagram. The spacing / distance d between the air-permeable counter electrode 21 and the air-permeable high-voltage electrode 20 corresponds to >=0mm. Preferably, the spacing d is between 0 and 6mm. The spacing depends on the value of the voltage applied to the conductive electrode 20. Plasma is formed in the ionization region 23 between the air-permeable counter electrode 21 and the air-permeable high-voltage electrode 20. The air-permeable high-voltage electrode 20 is provided with an insulating coating 22, which forms a dielectric and can also be referred to as a sheath.

[0071] As in Figure 6As shown in FIG. 1 , the electrodes 20 and 21 are arranged alternately with one another. The first and last electrode in the flow direction can be both a gas-permeable electrode 21 and a gas-permeable high-voltage electrode 20 .

[0072] In addition, Figure 5 The single gas-permeable counter electrode 21 shown in FIG. 1 can itself be constructed from a plurality of gas-permeable layers (n>=1). The same applies to the gas-permeable high-voltage electrode 20 .

[0073] Furthermore, the number of gas-permeable electrodes 21 between two gas-permeable high-voltage electrodes 20 can be greater than or equal to 1. This also applies in the opposite case, in which the number of gas-permeable high-voltage electrodes 20 between two gas-permeable counter electrodes 21 is greater than or equal to 1.

[0074] Regarding the voltage form, the gas permeable high voltage electrode 20 uses a voltage having U 峰值 >=500V(See Fig.11c ) and a pulsed voltage with a period duration T <= 1s. The pulsed voltage can be a positive or negative voltage type. As an alternative, with U 有效值 >=500V(See Fig.11d ) and an alternating voltage with a period duration T>=1s is possible. Different voltage forms are possible for the alternating voltage and the pulse-excited voltage. Here, for example, a sinusoidal, rectangular, triangular or sawtooth voltage form is used. The gas-permeable counter electrode is connected to a counter potential in order to ensure a variable voltage difference ΔU between the high-voltage electrode 20 and the counter electrode 21.

[0075] As an alternative, the gas-permeable counter electrode 21 can be grounded. For this application, the gas-permeable counter electrode 21 is electrically connected to the ground line PE (protective earth).

[0076] The odor filter 2 can have a high-pressure converter 4, which Fig.13 The high voltage converter 4 supplies high voltage or electrical energy to the high voltage electrode 20 and the counter electrode 21 via the connecting lines 40, 41 on the secondary side 44. The possible voltage variation curves on the secondary side 44 of the high voltage converter 4 are shown schematically as a block diagram. Fig.11c and 11d On the primary side 43 , the high-voltage converter 4 is supplied with voltage via the connection / connection line 42 , for example with direct current or alternating current.

[0077] With regard to the arrangement / orientation of the individual air-guiding electrodes 20, 21 relative to one another, these electrodes should preferably be arranged offset from one another as shown in FIGS. 8 to 10 in order to ensure optimal ionization of the air flowing through, which is laden with odor molecules, which in turn leads to optimal neutralization of the odor substances / odor molecules.

[0078] Furthermore, the individual electrodes can be offset relative to one another in the plane by 0 to 360° around the axis of rotation in the installed state. Figure 7 It is shown in Figure 7 The electrodes 20 , 21 are offset relative to each other by a rotation of 45°.

[0079] According to the concept of dielectric barrier discharge (DBE), when a time-varying voltage U, the so-called ignition voltage U, is applied between two electrodes having at least one dielectric under ambient conditions. 点火电压 , then a displacement current I appears between the two electrodes. The magnitude of the ignition voltage depends on many factors, such as electrode geometry, insulating material (dielectric), gap width d, voltage form, gas composition, etc. This displacement current I causes ionization of the air between the two electrodes. Through this ionization process in the ionization region (plasma region), active species, so-called reactive oxygen species (ROS) and reactive nitrogen species (RNS) are formed by impact ionization processes. These active species are energetically highly active molecules, which, in particular, combine with unpleasant odor molecules and other volatile organic compounds (VOC's), whereby these unpleasant odor molecules are chemically converted into other compounds. Therefore, odor reduction or even complete odor elimination occurs through the chemical process between odor molecules and active species.

[0080] Based on this process / this principle of action, in the filter unit according to the invention, air-permeable electrodes are used in the section for odor neutralization, which cause ionization of the air between the electrodes according to the principle of dielectric barrier discharge. This air ionization (plasma formation) in the ionization area causes the removal / neutralization of odor molecules and other volatile compounds (VOC's) that are olfactory unpleasant.

[0081] The present invention has a number of advantages.

[0082] The subject matter of the invention is a compact, self-sufficient ionizing filter unit which is able to remove both particles and also olfactory odor molecules from the air.

[0083] Due to its concept with porous electrodes for odor reduction, the ionizing filter unit requires significantly less space than plasma filters currently available on the market.

[0084] The plasma filter used according to the invention (system for odor neutralization) consists only of air-permeable electrodes arranged one after the other, through which the air flows. This simple invention designed for odor reduction makes the plasma unit cost-effective in terms of material and production costs.

[0085] The plasma cell (segment for odor neutralization) used according to the invention consists of porous or air-permeable electrodes arranged one after the other and has a much greater efficiency in odor reduction than other plasma filters. This is due to the fact that during operation, a plasma wall is formed by means of the porous electrodes, through which the air carrying the odor molecules flows. When the odor molecules in the air flow through this ionization area "plasma wall", a sufficient chemical reaction of these mentioned odor molecules with the active species occurs. In other words, a sufficient mixing of the odor molecules with other reactive oxygen species (ROS) and reactive nitrogen species (RNS) takes place. The air-permeable electrodes of the plasma cell cause better mixing of the air flowing through due to their geometrical properties.

[0086] Due to the effective mixing of the air and the resulting more effective removal of odor molecules and other VOC's therefrom, less electrical power (energy input) needs to be delivered for the same filtration efficiency compared to existing plasma systems.

[0087] The ionizing filter unit can be cleaned not only in a dishwasher but also by hand using a cleaning agent and water. As a result, the life of such an ionizing filter unit is unlimited. Both the gas-permeable electrode for odor reduction and the electrostatic filter can be washed in water to remove dirt and impurities. Currently available plasma filters are not suitable or are not intended for cleaning purposes according to the manufacturer's specifications. This applies in particular to cleaning uses in private households.

[0088] List of reference numerals:

[0089] 1 Filter unit

[0090] 2 Odor filter

[0091] 20 High voltage electrode

[0092] 21 Counter electrode (odor filter)

[0093] 22 Electrical insulation

[0094] 23 Ionization Region

[0095] 3 Electrostatic Filters

[0096] 30 Ionization Unit

[0097] 300 Discharge Electrode

[0098] 301 Grounded counter electrode (ionization cell)

[0099] 31 Separation unit

[0100] 310 Conductive deposition electrode plate

[0101] 311 Grounded deposition electrode plate

[0102] 312 Conductive deposited electrode

[0103] 313 Grounded deposition electrode

[0104] 4 High voltage converter

[0105] 40 High voltage electrode connection wire

[0106] 41 Connection wire for counter electrode

[0107] 42 Connectors for lower voltage

[0108] 43 Primary side

[0109] 44 Secondary side.

Claims

1. A filter unit for an air purification device, wherein the filter unit (1) comprises an odor filter (2) for neutralizing odors, the odor filter representing a device for generating plasma, characterized in that: The odor filter (2) comprises at least one air-permeable high-voltage electrode (20) and at least one air-permeable counter electrode (21), which are respectively formed by planar elements, and the at least one air-permeable high-voltage electrode (20) and the at least one air-permeable counter electrode (21) are arranged one after the other along the flow direction. The filter unit (1) comprises an electrostatic filter (3), wherein the electrostatic filter has an ionization unit (30) and a separation unit (31), The odor filter (2) is arranged after the electrostatic filter (3) along the flow direction. wherein at least one of the electrodes (20, 21) of the odor filter (2) has an insulating coating (22) on at least one surface, wherein the odor filter (2) has a high-voltage converter (4) by which a high voltage that varies over time can be generated for the high-voltage electrode (20) of the odor filter (2), The odor filter (2) and the electrostatic filter (3) are accommodated in a common housing, and the odor filter (2) and the electrostatic filter (3) can be removed from the housing.

2. A filter unit according to claim 1, wherein the separation unit (31) of the electrostatic filter (3) has at least one conductive deposition electrode (310, 312) and at least one grounded deposition electrode (311, 313), and the deposition electrode represents an airtight plate (310, 311) or the deposition electrode represents an air-permeable electrode (312, 313).

3. The filter unit according to claim 1 or 2, wherein the electrodes (20, 21) of the odor filter (2) are arranged along a direction inclined relative to the flow direction.

4. The filter unit according to claim 1 or 2, wherein at least one high-voltage electrode (20) and / or at least one counter electrode (21) are constructed in multiple layers.

5. The filter unit according to claim 1 or 2, wherein the at least one high-voltage electrode (20) and the at least one counter electrode (21) are made of an air-permeable material or an air-impermeable material having at least one air-through hole.

6. A filter unit according to claim 1 or 2, wherein at least one high-voltage electrode (20) and / or at least one counter electrode (21) is made of a perforated plate or a welded grid or a woven wire grid or a drawn metal mesh or a breathable sintered material or a breathable foam material.

7. The filter unit according to claim 1 or 2, wherein at least one high-voltage electrode (20) and a counter-electrode (21) are arranged relative to one another in such a way that their structures are located in the plane of the respective electrode in a manner twisted about an axis.

8. An air purification device, characterized in that: The air cleaning device comprises at least one filter unit (1) according to any one of claims 1 to 7.

9. The air purification device according to claim 8, characterized in that: The air purification device is a range hood device, and the filter unit (1) is arranged before a blower of the range hood device.

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