FILTER UNIT FOR AIR CLEANING DEVICE, AND AIR CLEANING DEVICE

Abstract

A filter unit for an air cleaning device includes an odor filter configured for odor neutralization and embodied as a device for plasma generation. The odor filter includes an air-permeable high-voltage electrode and an air-permeable counter electrode arranged behind one another in a direction of flow of air. Each of the air-permeable high-voltage electrode and the air-permeable counter electrode is formed by a panel element.

Claims

1.-14. (canceled)

15. A filter unit for an air cleaning device, said filter unit comprising an odor filter configured for odor neutralization and embodied as a device for plasma generation, said odor filter comprising an air-permeable high-voltage electrode and an air-permeable counter electrode arranged behind one another in a direction of flow of air, each of the air-permeable high-voltage electrode and the air-permeable counter electrode being formed by a panel element.

16. The filter unit of claim 15, further comprising an electrostatic filter which includes an ionization unit and a separation unit arranged downstream of the ionization unit in the direction of flow.

17. The filter unit of claim 16, wherein the separation unit of the electrostatic filter includes a live collecting electrode and a grounded collecting electrode, with the live collecting electrode and the grounded collecting electrode being air-impermeable plates or the live collecting electrode and the grounded collecting electrode being air-permeable electrodes.

18. The filter unit of claim 16, wherein the odor filter is arranged downstream of the electrostatic filter in the direction of flow.

19. The filter unit of claim 16, wherein the odor filter and the electrostatic filter are contained in a shared housing.

20. The filter unit of claim 15, wherein the air-permeable high-voltage electrode and the air-permeable counter electrode of the odor filter are arranged in an orientation which is inclined relative to the direction of flow.

21. The filter unit of claim 15, wherein at least one of the air-permeable high-voltage electrode and the air-permeable counter electrode of the odor filter has a surface on which an insulation coating is provided.

22. The filter unit of claim 15, wherein at least one of the high-voltage electrode and the counter electrode has a multilayered structure.

23. The filter unit of claim 15, wherein at least one of the high-voltage electrode and the counter electrode is made of an air-permeable material or an air-impermeable material with at least one air conduction opening.

24. The filter unit of claim 15, wherein at least one of the high-voltage electrode and the counter electrode is made of perforated plate, welded mesh, woven wire netting, expanded metal, sintered material and/or foamed material.

25. The filter unit of claim 15, wherein the high-voltage electrode and the counter electrode are arranged relative to each other in such a way that their structure is rotated about an axis in the plane of the respective one of the electrodes.

26. The filter unit of claim 15, wherein the odor filter includes a high-voltage transformer configured to generate a temporally changing high voltage for the high-voltage electrode of the odor filter.

27. An air cleaning device, comprising a filter unit, said filter unit comprising an odor filter configured for odor neutralization and embodied as a device for plasma generation, said odor filter comprising an air-permeable high-voltage electrode and an air-permeable counter electrode arranged behind one another in a direction of flow of air, each of the air-permeable high-voltage electrode and the air-permeable counter electrode being formed by a panel element.

28. The air cleaning device of claim 27, constructed in the form of a vapor extraction device, said filter unit being arranged upstream of the fan of the vapor extraction device.

29. The air cleaning device of claim 27, wherein the air-permeable high-voltage electrode and the air-permeable counter electrode of the odor filter are arranged in an orientation which is inclined relative to the direction of flow.

30. The air cleaning device of claim 27, wherein at least one of the air-permeable high-voltage electrode and the air-permeable counter electrode of the odor filter has a surface on which an insulation coating is provided.

31. The air cleaning device of claim 27, wherein at least one of the high-voltage electrode and the counter electrode has a multilayered structure.

32. The air cleaning device of claim 27, wherein at least one of the high-voltage electrode and the counter electrode is made of an air-permeable material or an air-impermeable material with at least one air conduction opening.

33. The air cleaning device of claim 27, wherein at least one of the high-voltage electrode and the counter electrode is made of perforated plate, welded mesh, woven wire netting, expanded metal, sintered material and/or foamed material.

34. The air cleaning device of claim 27, wherein the high-voltage electrode and the counter electrode are arranged relative to each other in such a way that their structure is rotated about an axis in the plane of the respective one of the electrodes.

Description

[0044] The invention is described again in greater detail with reference to the appended figures, in which:

[0045] FIG. 1 shows a schematic perspective view of an embodiment variant of the filter unit according to the invention;

[0046] FIG. 2 shows a schematic perspective view of a further embodiment variant of the filter unit according to the invention;

[0047] FIG. 3 shows a schematic perspective exploded view of an embodiment variant of the filter unit according to the invention;

[0048] FIG. 4 shows a schematic perspective exploded view of a further embodiment variant of the filter unit according to the invention;

[0049] FIG. 5 shows a schematic block diagram of an embodiment variant of the odor filter of the filter unit according to the invention;

[0050] FIG. 6 shows a schematic perspective view of an embodiment variant of the odor filter of the filter unit according to the invention;

[0051] FIG. 7 shows a schematic detail view of a further embodiment variant of the odor filter of the filter unit according to the invention;

[0052] FIGS. 8a, 8b and 8c show schematic illustrations of an embodiment variant of the electrode geometry of the odor filter of the filter unit according to the invention;

[0053] FIGS. 9a and 9b show schematic illustrations of a further embodiment variant of the electrode geometry of the odor filter of the filter unit according to the invention;

[0054] FIGS. 10a, 10b and 10c show schematic illustrations of a further embodiment variant of the electrode geometry of the odor filter of the filter unit according to the invention;

[0055] FIGS. 11a to 11d show schematic illustrations of possible voltage profiles of the voltage for the odor filter of the filter unit according to the invention;

[0056] FIGS. 12a and 12b show schematic illustrations of different geometries of the electrodes of the odor filter; and

[0057] FIG. 13 shows a schematic block diagram of an embodiment variant of a high-voltage transformer.

[0058] FIG. 1 shows a schematic perspective view of a first embodiment variant of the filter unit 1 according to the invention. The filter unit takes the form of an electrically ionizing filter unit 1 and is also referred to as a filter module/filter cartridge. The filter unit 1 consists of an odor filter 2, which is also referred to as a plasma filter, and an electrostatic filter 3. The function of the electrostatic filter 3 is to filter out solid and liquid particles (aerosols) from the airstream. The plasma filter 2 connected downstream thereof is used for odor neutralization of cooking odors and other VOCs in the airstream. The cited electrically ionizing filter module 1 consists of three segments as per FIG. 1. In particular, the filter unit 1 consists of a segment for particle charging which is also referred to as an ionization unit 30, a segment for particle separation which is also referred to as a separation unit 31, and the segment for odor neutralization which is also referred to as an odor filter 2 or plasma filter. All three segments 30, 31, 2 are spatially arranged one behind the other in the direction of air flow, this being indicated by a block arrow in the figures, and outwardly appear as an autonomous filter system.

[0059] Concerning the orientation of the individual segments 30, 31, 2 along the direction of air flow, the segment for particle charging 30 is arranged ahead of the segment for particle separation 31 in FIG. 1. The segment for odor neutralization 2 by means of plasma is preferably the last air treatment stage. This ensures that aerosols are filtered out of the cooking steam first, and the cooking odors are then neutralized. Alternatively, the segment for odor neutralization can also be spatially arranged between the other two segments or even in the first position ahead of the segment for particle charging.

[0060] FIG. 2 shows a further embodiment variant of the filter unit 1. This only differs from the embodiment variant shown in FIG. 1 in respect of the depth of the individual segments, i.e. their extent in the direction of flow.

[0061] The individual parts of the individual segments 2, 30, 31 of an embodiment variant of the filter unit 1 are illustrated in FIG. 3. For the purpose of particle filtration in the embodiment variant according to FIG. 3, use is made of an electrostatic filter 3 composed of the segment for particle charging 30 and the segment for particle separation 31. The particle charging is effected in the ionization unit 30 by means of a corona discharge. For this purpose, an emission electrode 300 is arranged in each case between two counter electrodes 301. In the ionization unit 30, the particles (solid and liquid) contained in the air are electrically charged by means of the corona discharge. In this case, the electrical particle charging of each individual particle is preferably achieved up to its maximum electrical saturation charge q.sub.s in the ionization unit 30.

[0062] The emission electrode 300 is exposed to an electrical high voltage in this case. Concerning said electrical voltage, either positive or negative voltage can be applied. A positive electrical voltage is preferred on the basis of the lower ozone emission. Concerning the voltage waveform, use can be made of either direct voltage with U>=1 kV DC (direct current) (see FIG. 11a) or alternatively impulse voltage with U.sub.peakvalue>=1 kV (see FIG. 11b) and a cycle duration T <=1 s. The impulse voltage can have a sinusoidal, rectangular, triangular or sawtooth voltage waveform. The grounded counter electrodes 301 are electrically connected to the electrical counter potential, to the protective conductor PE (protective earth) in this embodiment variant. Alternatively, it is also possible to apply a further mechanism for particle charging, which differs from the described principle of corona discharge, in the ionization unit 30 for the purpose of particle charging. Possibilities include particle charging by means of the dielectrically impeded barrier discharge (DBD) or photoemission.

[0063] The electrically charged particles then flow through the separation unit 31. The separation unit 31 takes the form of a plate separator in the embodiment variant according to FIG. 3. In the embodiment variant according to FIG. 4, the separation unit 31 is alternatively constructed using an air-permeable separation medium in the form of air-permeable electrodes 312, 313. Both options are possible and can be applied for the purpose of particle separation in the ionizing filter unit 1 according to intended use.

[0064] The plate separator is composed of at least one live plate-form collecting electrode plate 310 and at least one grounded plate-form collecting electrode plate 311, these being arranged alternately in each case. An electrical field strength E (=voltage/plate distance) forms between the alternately arranged plates 310, 311 during operation of the filter, and this in turn exerts an external force on the charged particle in each case. As a result, the charged particle is deflected towards the collecting electrodes 310, 311 and separated thereon. The particles collect on the surface of the plates 310, 311.

[0065] In the case of an air-permeable separation medium (see FIG. 4), the particle separation takes place at the live air-permeable collecting electrodes 312 and grounded air-permeable collecting electrodes 313, these being alternately arranged likewise. The illustrated air-permeable collecting electrodes 312, 313 can in principle be made of any air-permeable material/medium. Possible examples include welded mesh, wire cloth, fibrous materials, perforated plate, expanded metal, sintered plastics and foamed material or similar air-permeable media. If porous plastic media are used, they must be made in such a way as to be electrically conductive in respect of their specific properties, so that the electrical field can be established between the individual layers.

[0066] Concerning the voltage type, a positive or negative voltage can be used for the live collecting electrode plate 310 or the live air-permeable collecting electrode 312. Concerning the voltage waveform, it is possible to use either direct voltage with U>=1 kV DC (see FIG. 11a) or alternatively impulse voltage with U.sub.peakvalue>=1 kV (see FIG. 11b) and a cycle duration T<=1 s. The impulse voltage can have a sinusoidal, rectangular, triangular or sawtooth voltage waveform. The grounded collecting electrode plate 311 and the grounded air-permeable collecting electrode 313 respectively are electrically connected to the counter potential, here the protective conductor interface PE (protective earth).

[0067] The plasma filter 2 as per FIG. 3 and FIG. 4 consists of at least one air-permeable high-voltage electrode 20 (n>=1) and at least one air-permeable counter electrode 21 (n>=1). The porous electrodes 20, 21 illustrated in FIG. 3 and FIG. 4 can in principle be made of any material/medium which is air-permeable and electrically conductive or antistatic. Possible examples include perforated sheet metal, e.g. perforated plate, welded mesh, woven wire netting, expanded metal, sintered materials and foamed material.

[0068] For a better understanding, such geometries of the electrodes of the odor filter 2 are partially illustrated in FIGS. 8 to 10. In FIG. 8a, the air-permeable counter electrode 21 is formed by a woven wire netting which is shown in FIG. 8b. The air-permeable high-voltage electrode 20 in the embodiment variant according to FIG. 8a is formed by a welded mesh which is shown in FIG. 8c. The welded mesh is electrically insulated. In FIG. 9a, the air-permeable counter electrode 21 and the air-permeable high-voltage electrode 20 are each formed by a perforated plate which is shown in FIG. 9b. The perforated plate which forms the air-permeable high-voltage electrode 20 is preferably electrically insulated. In FIG. 10a, the air-permeable counter electrode 21 and the air-permeable high-voltage electrode 20 are each formed by an expanded metal. The expanded metal forming the air-permeable counter electrode 21 is shown in FIG. 10b and the expanded metal forming the air-permeable high-voltage electrode 20 is shown in FIG. 10c and is electrically insulated.

[0069] If plastic media are used as air-permeable material for the electrodes 20, 21 of the odor filter 2, at least one must be made in such a way as to be electrically conductive or antistatic having a surface resistance R<=10.sup.11 Ohms in respect of its specific properties, so that an electrical field can be established when an electrical voltage difference ΔU is applied between the electrodes 20, 21 and ionization takes place.

[0070] FIGS. 12a and 12b show further embodiment variants of the geometry of the electrodes of the odor filter. In FIG. 12a, each of the electrodes 20, 21 is pleated. In FIG. 12b, each of the electrodes 20, 21 has a wavy structure. Although the distance between the electrodes 20, 21 varies in FIG. 12b, the distance is preferably identical over the surface area of the electrodes.

[0071] FIG. 5 schematically shows the structure of the odor filter in a block diagram. The interval/distance d between the air-permeable counter electrode 21 and the air-permeable high-voltage electrode 20 is >=0 mm. The distance d is preferably between 0 and 6 mm. The distance is dependent on the magnitude of the electrical voltage applied to the live electrode 20. The plasma forms in the ionization zone 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 insulation coating 22 which forms the dielectric and can also be referred to as sheathing.

[0072] As shown in FIG. 6, the electrodes 20 and 21 are arranged alternately in relation to each other. The first and last electrode in the direction of flow can be either an air-permeable electrode 21 or an air-permeable high-voltage electrode 20.

[0073] Furthermore, the individual air-permeable counter electrode 21 shown in FIG. 5 can itself be composed of a plurality of air-permeable layers (n>=1). The same applies to the air-permeable high-voltage electrode 20.

[0074] Furthermore, the number of air-permeable electrodes 21 between two air-permeable high-voltage electrodes 20 can be greater than or equal to 1. The same applies in the opposite case likewise, i.e. the number of air-permeable high-voltage electrodes 20 between two air-permeable counter electrodes 21 is greater than or equal to 1.

[0075] Concerning the voltage waveform, an impulse voltage with U.sub.peakvalue>=500 V (see FIG. 11c) and a cycle duration T<=1 s is used for the air-permeable high-voltage electrode 20. The impulse voltage can be a positive or negative voltage type. Alternatively, a further possibility is an alternating voltage with U.sub.effectivevalue>=500 V (see FIG. 11d) and a cycle duration T>=1 s. Various voltage waveforms are possible for the alternating voltage and the impulse voltage. For example, a sinusoidal, rectangular, triangular or sawtooth voltage waveform can be used. The air-permeable counter electrode is connected to the electrical counter potential, so that a changing electrical voltage difference ΔU can be guaranteed between the high-voltage electrode 20 and the counter electrode 21.

[0076] Alternatively, the air-permeable counter electrode 21 can be grounded. For this, the air-permeable counter electrode 21 is electrically connected to the protective conductor PE (protective earth).

[0077] The odor filter 2 can have a high-voltage transformer 4, which is shown schematically as a block diagram in FIG. 13. This high-voltage transformer 4 supplies the high-voltage electrode 20 and counter electrode 21 with electrical high voltage or electrical energy on the secondary side 44 via the power cables 40, 41. Possible voltage profiles on the secondary side 44 of the high-voltage transformer 4 are shown in the FIGS. 11c and 11d. On the primary side 43, the electrical power supply to the high-voltage transformer 4 is provided via the connection interface or power cables 42, e.g. using direct current or alternating current.

[0078] Concerning the relative arrangement/orientation of the individual air-conducting electrodes 20, 21, these are preferably so arranged as to be offset relative to each other as shown in the FIGS. 8 to 10 in order to ensure optimal ionization of the air which flows through and is laden with odor molecules, thereby in turn ensuring optimal neutralization of the odorous substances/odor molecules.

[0079] Furthermore, in the installed state the individual electrodes can be offset in the plane about an axis of rotation from 0 to 360° relative to each other. This is shown by way of example in FIG. 7, in which the electrodes 20, 21 are so positioned as to be offset i.e. rotated by 45° relative to each other.

[0080] According to the concept of the dielectrically impeded barrier discharge (DBD), an electrical displacement current I is produced between two electrodes with at least one dielectric when a temporally changing electrical voltage U, the so-called ionization voltage U.sub.ionizationvoltage, is applied between these two electrodes under environmental conditions. The magnitude of the ionization voltage depends on many factors, e.g. the electrode geometry, the insulation material (dielectric), the gap width d, the voltage waveform, the gas composition, etc. Due to this ionization process in the ionization zone (plasma zone), reactive species are formed as a result of impact ionization processes, namely reactive oxygen species (ROS) and reactive nitrogen species (RNS). These reactive species are energetically highly reactive molecules which enter into chemical compounds with inter alia unpleasant odor molecules and other volatile organic compounds (VOCs), whereby these unpleasant odor molecules are chemically transformed into other chemical compounds. By means of chemical processes between the odor molecules and the reactive species, odors are consequently reduced or even eliminated completely. In accordance with this process/manner of functioning, air-permeable electrodes are used in the segment for odor neutralization within the inventive filter unit, resulting in ionization of the air between the electrodes in accordance with the principle of the dielectrically impeded barrier discharge.

[0081] This ionization of the air in the ionization zone (plasma formation) results in the depletion/neutralization of olfactorily unpleasant odor molecules and other volatile chemical compounds (VOCs).

[0082] The present invention has a range of advantages.

[0083] The subject matter of the present invention is a compact autonomous ionizing filter unit which can eliminate both particles and olfactorily unpleasant odor molecules from the air.

[0084] By virtue of its design with the porous electrodes for reducing odors, the ionizing filter unit requires considerably less space than plasma filters which are currently available on the market.

[0085] The plasma filter (system for odor neutralization) that is used according to the invention consists solely of air-permeable electrodes which are arranged one behind the other and through which the air flows. By virtue of this simple invention for odor reduction, the plasma unit is cost-efficient with regard to the material and manufacturing costs.

[0086] The plasma unit (segment for odor neutralization) that is used according to the invention consists of porous or air-permeable electrodes which are arranged one behind the other and, in comparison with other plasma filters, has a far greater efficiency in respect of odor reduction. This is because a plasma wall is established by the porous electrodes during operation, and the air laden with odor molecules flows through said plasma wall. When the odor molecules in the air flow through this ionization zone or “plasma wall”, these odor molecules undergo a complete chemical reaction with the reactive species. In other words, a complete intermixture of odor molecules and other reactive oxygen species (ROS) and reactive nitrogen species (RNS) occurs. Due to their geometric properties, the air-permeable electrodes of the plasma unit result in a better intermixture of the air flowing through.

[0087] As a result of the efficient intermixture of the air and consequently more efficient depletion of odor molecules and other VOCs, less electrical power (energy input) is required for the same filter efficiency in comparison with existing plasma systems.

[0088] The ionizing filter unit can be cleaned both in the dishwasher and by hand using detergent and water. The service life of such an ionizing filter unit is therefore unlimited. Both the air-permeable electrodes for odor reduction and the electrostatic filter can be rinsed of dirt and impurities. The existing plasma filters are not suitable for cleaning or even designed for this, depending on the manufacturer. This applies in particular to cleaning in the context of private domestic use.

LIST OF REFERENCE CHARACTERS

[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 zone

[0095] 3 Electrostatic filter

[0096] 30 Ionization unit

[0097] 300 Emission electrode

[0098] 301 Grounded counter electrode (ionization unit)

[0099] 31 Separation unit

[0100] 310 Live collecting electrode plate

[0101] 311 Grounded collecting electrode plate

[0102] 312 Live collecting electrode

[0103] 313 Grounded collecting electrode

[0104] 4 High-voltage transformer

[0105] 40 Power cable of the high-voltage electrode

[0106] 41 Power cable of the counter electrode

[0107] 42 Low-voltage connection interface

[0108] 43 Primary side

[0109] 44 Secondary side