Air filter device for air conditioning system

Abstract

The invention relates to an air filter device for an air conditioning system, in particular for separating particles, preferably dirt particles, from air. The air filter device includes: an air path through which air can flow in a flow direction; an ion generator arranged in the air path for generating ions in the air path; and a grid structure made of an electrically conductive material arranged in the air path upstream of the ionizer with respect to the flow direction and constituting a first electrode. A filter element is arranged in the air path downstream of the ionizer with respect to the flow direction, the filter element having a layer forming a second electrode. Furthermore, the air filter device comprises a high voltage source having an electrical terminal and an electrical counter terminal for generating a high voltage between the terminal and the counter terminal. The terminal is electrically connected to the ionizer or to an injection electrode of the ionizer, and the counter terminal is electrically connected to the first and second electrodes.

Description

Technical Field

[0001] The invention relates to an air filter device for air conditioning facilities. Background Art

[0002] Modern air conditioning systems for air conditioning the vehicle interior of a motor vehicle typically include filter elements which serve to remove pollutants, harmful gases, dust particles and unpleasant odors from the air conducted into the vehicle interior.

[0003] What is proved to be problematic here is precisely the high dust load in the surrounding environment of the motor vehicle and then the surrounding environment of the air conditioning device, which just needs to realize filtering dust from the air to be introduced into the vehicle interior space and puts forward a particularly high requirement. For this reason, it is known that a filter element with a fiber filter layer is used to clean dust particles. Since the structure space for the use of air conditioning devices in modern motor vehicles is typically limited, the structure space provided to such filter elements in the air conditioning devices is relatively small. However, in order to still ensure that a large amount of air can be transported to the vehicle interior space by means of air conditioning devices, the filter element must have a lower flow resistance so that the pressure loss generated in the air is also kept lower. For this reason, traditional filter elements are usually equipped with an open-pore filter fiber layer for particle separation, so that the mechanical dust separation efficiency of the filter element realized thus appears relatively low.

[0004] To solve this problem, it is known to improve the separation of dust particles by electrostatic charging. However, the electrostatic reserve generated during the production process causes the filter element to fail relatively quickly in actual operation as the filter element ages and is thus increasingly loaded with dust. Summary of the invention

[0005] Therefore, the task of the present invention is to point out a new path in the development of air filter devices. In particular, an improved embodiment should be provided for such air filter devices, so that the air filter devices utilize the above-mentioned working principle of electrostatic charging and achieve improved particle separation throughout the life cycle of the filter element.

[0006] This object is achieved by the subject matter of the independent patent claims. Preferred embodiments are the subject matter of the dependent patent claims.

[0007] The basic idea of ​​the invention is therefore to arrange a counter electrode upstream of an ion generator having a plurality of so-called ejection electrodes (the relevant technicians also refer to the ejection electrodes as "corona ejection electrodes"), and the counter electrode is arranged in the air path electrically separated from the ejection electrodes. In this way, an electric field can be generated in the air path, by which particles present in the air can be ionized.

[0008] According to the invention, the electrostatically chargeable filter element arranged downstream of the ejection electrode of the ionizer is electrically connected to the counter electrode arranged upstream of the ionizer, thereby creating a further counter electrode downstream of the ionizer in addition to the counter electrode arranged upstream of the ionizer.

[0009] As a result, an electric field is generated between the ejection electrode of the ionizer and the counter electrodes, which leads to improved charging of the particles and a polarization effect in the filter element. In addition, due to the polarization effect of the filter element, the efficiency of particle separation is improved during long-term operation of the air filter device, even when the filter element has previously been loaded with a large number of particles.

[0010] As a result, the above-described measures provide an air filter device in which an efficient separation of particles, in particular dirt particles, from air conducted through the air path is ensured over the entire service life of the air filter device or of a filter element used in the air filter device.

[0011] Specifically, the air filter device according to the present invention comprises an air path through which air can flow in the flow direction. An ionizer for generating ions in the air path is arranged in the air path of the air filter device, and the ionizer preferably has an ejection electrode. In the air path, a grid structure made of a conductive material is arranged upstream of the ionizer with respect to the flow direction, and the grid structure constitutes a first electrode. The first electrode constitutes a counter electrode relative to the ejection electrode and charges the particles upstream of the ejection electrode.

[0012] In the air path, downstream of the ionizer in terms of the flow direction, a filter element is arranged, which has a layer forming the second electrode. The layer is made of or includes an electrically conductive material. The filter element can preferably be configured as a pleated bellows, ie, has a bellows-like geometry.

[0013] In addition, the air filter device also includes a high voltage source having an electrical terminal and an electrical counter-terminal for generating a high voltage preferably between -5 kV and -15 kV between the electrical terminal and the electrical counter-terminal. According to the invention, the terminal of the high voltage source is electrically connected to the ionizer, and the counter-terminal of the high voltage source is electrically connected to the first and second electrodes.

[0014] Preferably, in order to generate the corona discharge, a DC voltage with negative polarity is applied; this is because compared with the corona discharge with positive polarity, the corona discharge with negative polarity ensures that the corona flow from the electrons has a higher stability and a higher value. Therefore, it is preferred to configure the electric terminal of the high voltage source as a negative terminal and the electric counter terminal as a positive terminal of the high voltage source.

[0015] Alternatively to this, however, it is also possible within the scope of the invention to configure the electrical terminal of the high-voltage source as the positive terminal of the high-voltage source and the electrical counter-terminal as the negative terminal of the high-voltage source.

[0016] In a preferred embodiment, the filter element comprises a layer of electrically insulating material, in particular dielectric material, through which air can flow for separating particles from the air, the layer of electrically insulating material being arranged in the air path upstream or downstream of the layer forming the second electrode. Particularly expediently, the second layer is designed to be electrostatically chargeable. This improves the filtering effect of the second layer and thus of the entire filter element.

[0017] According to an advantageous development, the electrically conductive layer of the filter element which forms the second electrode is formed from activated carbon or at least comprises such activated carbon.

[0018] Particularly expediently, the two layers of the filter element are stacked one behind the other in the flow direction. The electric field generated by the electrically conductive layer causes the ionized particles to strike the electrically insulating layer and be filtered out of the air by the electrically insulating layer.

[0019] According to an advantageous improvement, the grid structure comprises at least two, preferably a plurality of, first grid bars arranged at a distance from each other, which extend transversely, preferably orthogonally, to the flow direction in the air path. In this improvement, the grid structure comprises at least two, preferably a plurality of, second grid bars arranged at a distance from each other, which extend transversely, preferably orthogonally, to both the first grid bars and the flow direction in the air path. The grid structure forming the first electrode can be made of a wire made of stainless steel. The grid structure can have openings between 1 mm × 1 mm and 10 mm × 10 mm, preferably between 3 mm × 3 mm and 6 mm × 6 mm. The diameter of the wire forming the grid must be selected so that the grid has the required mechanical stability. Furthermore, it must be provided that the corona discharge is generated in such a way that there is no spark discharge between the grid and the sharp-edged electrode bars. Furthermore, it must be provided that the generation of a reverse corona discharge from the grid is excluded.

[0020] In a preferred embodiment, the first electrode or the grid structure is electrically connected to the second electrode (ie the conductive layer in the filter element), so that both electrodes have the same electrical potential, which has a favorable effect on the field line course of the electric field generated by the two electrodes and the polarization to be achieved.

[0021] It is therefore particularly preferred that the first and second electrodes can be electrically connected directly to one another so that they have the same electrical potential.

[0022] In a further preferred embodiment, the ionizer comprises an ionizer electrode for generating ions in the air path. The ionizer electrode can in turn have a plurality of so-called spray electrodes.

[0023] Particularly preferably, the ionizer electrode comprises at least one electrode strip, from which protrudes toward the first electrode, preferably counter to the flow direction, at least one electrode tip, particularly preferably configured as a needle, for generating ions. Preferably, the electrode tips extend respectively counter to the flow direction. Each electrode tip can form a respective ejection electrode of the ionizer. With this geometry of the ionizer electrode, extremely high electric fields with field strengths between 10 kV / mm and 40 kV / mm can be generated, which is conducive to generating a large number of ions and thus charging particles in the gas flow.

[0024] In a further preferred embodiment, at least one electrode strip extends in the air path, in particular in a straight line, along a direction of extension transversely, preferably orthogonally, to the flow direction.

[0025] According to an advantageous refinement, at least two, preferably a plurality of electrode tips protrude from at least one electrode strip, which are preferably arranged spaced apart from one another along the extension direction of the electrode strip. In this way, ions can be generated over the entire path cross section of the air path.

[0026] In another preferred embodiment, the ionizer electrode comprises at least two, preferably a plurality of electrode strips arranged spaced apart from each other, which preferably extend parallel to each other. This measure is also conducive to the generation of ions over the entire cross section of the air path. Particularly preferably, the electrode tip extends in the opposite direction of the flow.

[0027] Particularly preferably, at least two, preferably a plurality, particularly preferably all adjacent electrode strips are arranged at a spacing, measured orthogonally to the extension direction, of between 20 mm and 60 mm, preferably between 25 mm and 35 mm. This ensures that the pressure drop in the air caused by the ionizer is relatively low.

[0028] Particularly preferably, at least two, preferably a plurality, particularly preferably all adjacent electrode tips are arranged at a distance from one another measured in the extension direction of between 1 mm and 30 mm, preferably between 5 mm and 9 mm. This prevents the electrode strip from causing a strong pressure drop in the air that strikes the electrode strip or flows past it.

[0029] Particularly expediently, the electrode tips are arranged in a grid-like manner in the air path. This measure leads to an improved field line profile of the corona field in the air path.

[0030] According to an advantageous development, at least one electrode tip tapers toward the first electrode, in particular conically, ie, thus particularly preferably counter to the flow direction. This preferably applies to a plurality of electrode tips, particularly preferably to all electrode tips.

[0031] The effectiveness of the polarization effect applied by the electric field to the filter element depends on the strength of the electric field generated by the electrodes. The higher the strength of the electric field, the greater the polarization effect generated. Therefore, the corona discharge electrode should be as close as possible to the inlet surface of the filter element. In another preferred embodiment, the distance between the ionizer, in particular the electrode strips of the ionizer and the filter element is at most 30 mm, preferably at most 7 mm.

[0032] Particularly preferably, the material of the grid structure or the material of the (first and / or second) grid bars can be steel, in particular stainless steel or include steel. Alternatively or additionally, in this variant, the material of the ionizer or the material of the ionizer electrodes can be steel, in particular stainless steel or include steel, in particular stainless steel.

[0033] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated description of the figures in conjunction with the drawings.

[0034] It is understood that the features mentioned above and yet to be explained below can be used not only in the respectively stated combination but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0036] In which respectively schematically:

[0037] Figure 1 A perspective view showing an example of an air filter device according to the present invention;

[0038] Figure 2 Show Figure 1 A side view of an air filter assembly;

[0039] Figure 3 Show Figure 1 and Figure 2 Top view of a section of an air filter device. DETAILED DESCRIPTION

[0040] Figure 1 A perspective view showing an example of an air filter device 1 according to the invention, Figure 2 is shown in side view, and Figure 3 Shown in top view. Figure 1 and Figure 2 The air filter device 1 comprises an air path 2 through which air L can flow along a flow direction S. In addition, the air filter device 1 further comprises an ion generator 3 arranged in the air path 2 for generating ions in the air path 2. In addition, the air filter device 1 further comprises a grid structure 4 made of a conductive material, which is arranged upstream of the ion generator 3 in the air path 2 with respect to the flow direction S and constitutes a first electrode 5a.

[0041] like Figures 1 to 3 It can be seen that the grid structure 4 has a plurality of first grid bars 11a arranged at a distance from each other, which extend in the air path 2 orthogonally to the flow direction S. In addition, the grid structure 4 also includes a plurality of second grid bars 11b arranged at a distance from each other, which extend in the air path 2 orthogonally both to the first grid bars 11a and to the flow direction S. Steel, in particular stainless steel, is a possible material for the grid structure 4 or the first and second grid bars 11a, 11b. The first and second grid bars 11a, 11b can be spread out in a plane extending perpendicularly to the flow direction S.

[0042] Furthermore, the air filter device 1 comprises a filter element 6 which is arranged downstream of the ionizer 3 in the air path 2 with respect to the flow direction S. The filter element 6 in turn comprises a layer 7 which forms a second electrode of the air filter device 1. In the present example, this layer 7 is made of an electrically conductive material, for example.

[0043] In the example of the figures, the filter element 6 further comprises a layer 9 made of an electrically insulating material through which the air L can flow and which serves to separate particles from the air L. The layer 9 is arranged in the air path 2, for example, upstream of the layer 7 forming the second electrode 5 b. The layer 7 of the filter element 6 forming the second electrode 5 b consists of activated carbon 10. The two layers 7, 9 of the filter element 6 can be stacked one after the other in the flow direction S.

[0044] In addition, the air filter device 1 also includes a high voltage source 8 having an electrical terminal 8a and an electrical counter-terminal 8b, which is used to generate a high voltage between the terminal 8a and the counter-terminal 8b. Suitably, a voltage between 5 kV and 15 kV can be provided between the terminal 8a and the counter-terminal 8b by the high voltage source 8. As shown in the figure, the terminal 8a is preferably configured as a negative terminal, and the counter-terminal 8b is configured as a positive terminal. However, an inverted configuration can also be imagined, and therefore, in this inverted configuration, the terminal 8a is configured as a positive terminal, and the counter-terminal 8b is configured as a negative terminal (not shown).

[0045] according to Figure 1 The terminal 8a configured as the negative terminal is electrically connected to the ion generator 3, and the negative terminal 8b configured as the positive terminal is electrically connected to the first and second electrodes 5a, 5b.

[0046] The ionizer 3 has an ionizer electrode 14 including an ejection electrode 17 for generating ions. The ionizer electrode 14 comprises a plurality of electrode strips 12 arranged at a distance from each other, wherein a plurality of electrode tips 13 each configured in a needle shape protrude from each electrode strip 12 toward the first electrode 5a, from which the ions for charging the particles can be generated. The electrode tips 13 constitute the ejection electrode 17. The electrode tips 13 extend away from the respective electrode strips 12 respectively in the opposite direction of the flow direction S toward the grid structure 4.

[0047] like Figures 1 to 3 As shown in the figure, the electrode tip 13 can be arranged in the air path 2 in a grid shape, and can also taper conically toward the first electrode 5a. The material of the ionizer 3 or the ionizer electrode 14 and its electrode strips 12 can be steel, such as stainless steel. The individual electrode strips 12 extend in a straight line in the air path 2 along a common extension direction E extending orthogonally to the relative flow direction S. The distance between the electrode strips 12 of the ionizer 3 and the filter element 6 is at most 30 mm, preferably at most 7 mm.

[0048] In the exemplary embodiment, all adjacent electrode strips 12 are arranged at a spacing A1 measured orthogonally to the extension direction E, which is between 15 mm and 60 mm, preferably between 25 mm and 35 mm. In addition, in the exemplary embodiment, all adjacent electrode tips 13 are arranged at a spacing measured along the extension direction E, which is between 1 mm and 30 mm, preferably between 5 mm and 9 mm.

Claims

1. An air filter device (1) for an air conditioning system, the air filter device being used in particular for separating particles, preferably dirt particles, from air (L), the air filter device comprising: - an air path (2) through which air (L) can flow in the flow direction (S), - an ion generator (3) arranged in the air path (2) for generating ions in the air path (2), preferably having a plurality of ejection electrodes (17), - a grid structure (4) made of an electrically conductive material, arranged upstream of the ionizer (3) in the air path (2) with respect to the flow direction (S) and constituting a first electrode (5a), - a filter element (6) arranged downstream of the ionizer (3) in the air path with respect to the flow direction (S), the filter element having a layer (7) constituting the second electrode (5b), the layer comprising or consisting of an electrically conductive material, - a high-voltage source (8) having an electrical terminal (8a) and an electrical counter-terminal (8b), the high-voltage source being used to generate a high voltage (HV), in particular between 5 kV and 15 kV, between the terminal (8a) and the counter-terminal (8b), - in, The terminal (8a) is electrically connected to the ion generator (3), and the counter terminal (8b) is electrically connected to the first and second electrodes (5a, 5b).

2. The air filter device according to claim 1, It is characterized in that - the electrical terminal (8a) is configured as a negative terminal of the high voltage source (8) and the electrical counter terminal is configured as a positive terminal of the high voltage source, or - the electrical terminal (8a) is configured as a positive terminal of the high voltage source (8), and the electrical counter terminal is configured as a negative terminal of the high voltage source.

3. The air filter device according to claim 1 or 2, It is characterized in that The filter element (6) comprises a layer (9) of electrically insulating material through which air can flow for separating particles from the air (L), the layer of electrically insulating material being arranged in the air path upstream or downstream of the layer (7) forming the second electrode (5b).

4. The air filter device according to claim 3, It is characterized in that The layer (7) of the filter element (6) forming the second electrode (5b) is formed from activated carbon (10) or comprises activated carbon (10).

5. An air filter device according to any one of the preceding claims, It is characterized in that - the grid structure (4) comprises at least two, preferably a plurality of, first grid bars (11a) arranged spaced apart from one another, and extending in the air path (2) transversely, preferably orthogonally, to the flow direction (S), The grid structure (4) comprises at least two, preferably a plurality of, second grid bars (11b) arranged at a distance from one another, which extend in the air path (2) transversely, preferably orthogonally, both to the first grid bars (11a) and to the flow direction (S).

6. An air filter device according to any one of the preceding claims, It is characterized in that The first electrode (5a) or the grid structure (4) is electrically connected to the second electrode (5b).

7. An air filter device according to any one of the preceding claims, It is characterized in that The grid structure (4) and the filter element (6) are electrically connected to one another.

8. An air filter device according to any one of the preceding claims, It is characterized in that The ionizer (3) comprises an ionizer electrode (14) for generating ions in the air path (2).

9. An air filter device according to any one of the preceding claims, It is characterized in that The ionizer electrode (14) comprises at least one electrode strip (12), from which at least one electrode tip (13), preferably designed in the form of a needle, projects toward the first electrode (5a) for generating ions.

10. The air filter device according to claim 9, It is characterized in that The at least one electrode strip (12) extends in the air path (2), in particular in a straight line, along an extension direction (E) transversely, preferably orthogonally, to the flow direction (S).

11. The air filter device according to claim 8 or 9, It is characterized in that - at least two, preferably a plurality of, electrode tips (13) protrude from at least one electrode strip (12), preferably arranged spaced apart from one another along the extension direction (E) of the electrode strip (12), wherein at least one electrode tip (13), preferably all electrode tips (13), extend counter to the flow direction (S).

12. An air filter device according to any one of the preceding claims, It is characterized in that The ionizer electrode (14) comprises at least two, preferably a plurality of, electrode strips (12) which are arranged spaced apart from one another and preferably extend parallel to one another.

13. The air filter device according to claim 12, It is characterized in that At least two, preferably a plurality, particularly preferably all adjacent electrode strips (12) are arranged at a spacing (A1) measured orthogonally to the extension direction (E) between one another, which spacing (A1) is between 15 mm and 60 mm, preferably between 25 mm and 35 mm.

14. The air filter device according to any one of claims 11 to 13, It is characterized in that At least two, preferably a plurality, particularly preferably all adjacent electrode tips (13) are arranged at a distance from one another measured in the extension direction (E) of between 1 mm and 30 mm, preferably between 5 mm and 9 mm.

15. The air filter device according to any one of claims 11 to 14, It is characterized in that The electrode tips (13) are arranged in a grid-like manner in the air path (2).

16. An air filter device according to any one of claims 11 to 15, It is characterized in that At least one, preferably a plurality, particularly preferably all of the electrode tips (13) tapers toward the first electrode (5a), in particular conically, preferably counter to the flow direction (S).

17. An air filter device according to any one of the preceding claims, It is characterized in that The distance between the ionizer (3), in particular the electrode strips (12) of the ionizer (3), and the filter element (6) is at most 30 mm, preferably at most 7 mm.

18. An air filter device according to any one of the preceding claims, It is characterized in that - the material of the grid structure (4) or the material of the (first and / or second) grid bars (11a, 11b) is steel, in particular stainless steel, or comprises steel; or / and The material of the ionizer (3) or the material of the ionizer electrode (14) is steel, in particular stainless steel, or comprises steel, in particular stainless steel.

Images