Air filter device and vehicle air conditioning system equipped with the same

Abstract

The invention relates to an air filter device and a vehicle air conditioning system equipped with the air filter device. A flow path (30) of an air flow formed by air is guided through the air filter device. The air filter device has an ionizer (10) arranged in the flow path (30) and an electrostatically charged filter element (20) arranged downstream of the ionizer (10) in the flow path (30) such that an air flow can flow through the ionizer (10) and the filter element (20). Furthermore, the ionizer (10) has an electrode (11) for generating a corona discharge, which electrode can be electrically conductively connected to a high-voltage source (4) of the air filter device (1), a counter electrode (15) associated with the electrode (11), and an electrically conductive grid element (40) arranged upstream of the ionizer (10) in the current path (30). It is essential for the invention that the counter electrode (15) is electrically conductively connected to the electrically conductive, planar filter layer (21) of the filter element (20) and to the grid element (40).

Description

Technical Field

[0001] The invention relates to an air filter device according to the preamble of claim 1. The invention also relates to a vehicle air conditioning system equipped with at least one air filter device. Background Art

[0002] An air filter device of the type mentioned at the outset is known from WO 2020 263 171 A1. Further air filter devices are described in EP 3 056 364 B1, US 20 210 021 107 A1, WO 2021 226 639 A2, KR 102 205 159 B1, EP 3 488 933 A1 and US 2016 229 267 A1.

[0003] Air filter devices of the above type are provided for removing pollutants such as fine dust, harmful gases and unpleasant odors from the air. Air filter devices are used in particular in vehicle air conditioning systems of vehicles, where they purify in particular the outside air introduced from the environment into the passenger compartment of the vehicle. As a result, a comfortable and healthy interior atmosphere with high air quality can be provided in the passenger compartment.

[0004] Urban areas present challenges for such air filtration devices. The outside air there can have very high and possibly health-damaging fine dust pollution. For example, in large cities, pollution is known that, on a daily average, is significantly above the PM 500 level of 15 μg / m3 recommended by the World Health Organization. 2.5 Such conditions place high demands on air filter devices, in particular they should be able to ensure a high filter separation rate for the corresponding particles in such urban areas, in a maintenance-free operation that is as long as possible.

[0005] In order to achieve this, manufacturers of corresponding air filter devices strive to introduce static electricity into the filter elements installed in the air filter devices during the manufacture of the air filter devices. As a result, particles carried in the external air can be separated not only mechanically at the filter element, but also by electrostatic effects. By electrostatic separation, the smallest particles, especially fine dust particles, can be reliably separated from the air.

[0006] The static charge introduced into the filter element undesirably weakens over time, in particular as the filter element ages and / or as the filter element is loaded. This reduces the weight of electrostatic separation, which usually accounts for the largest share of all separation methods in today's filters.

[0007] Corona discharge ionizers are used to enhance the electrostatic separation of filter elements. The ionizer generates a corona discharge (positive or negative polarity), which results in the generation of electrons and ions that ionize the gas molecules. The ionized gas molecules then combine with the particles carried in the air flow, thereby improving the electrostatic separation of the filter element. However, known air filter devices, after a more or less operating time, are no longer able to meet the requirements in particular with regard to the required filter performance. Therefore, early maintenance and, if necessary, replacement of the filter element are required. If this does not happen, the vehicle occupants may be exposed to high particle contamination, depending on the aging state of the filter. Summary of the invention

[0008] Therefore, the object of the present invention is to provide an improved or at least another embodiment of an air filter device. In particular, a vehicle air conditioning system having at least one such air filter device should be described.

[0009] In the invention, this object is achieved in particular by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims and the description.

[0010] The present invention recognizes that the separation effect of the filter element and the service life of the filter element can be increased by combining improved polarization of the air filter device with optimized ionization / particle charging.

[0011] Therefore, an air filter device is proposed, especially a cabin air filter device for a vehicle air conditioning device, wherein the flow path of an air flow formed by air is guided through the air filter device. The air filter device has an ionizer arranged in the flow path for ionizing the air flow and a filter element with electrostatic charge for filtering the air flow arranged downstream of the ionizer in the flow path, so that the ionizer and the filter element can be flowed through by the air flow formed by the air. In addition, it is provided that the ionizer has at least one electrode for generating corona discharge in the air flow, which is electrically connected or can be electrically connected to a high voltage source of the air filter device, at least one counter electrode assigned to at least one electrode, and an electrically conductive and planar grid element arranged upstream of the electrode and the counter electrode in the current path, which grid element is suitably used as a counter electrode. Importantly, at least one counter electrode is electrically conductively connected to the conductive, planar filter layer and the grid element of the filter element. Thus, the air filter device is designed so that during the operation of the air filter device, an electric field is generated between the ionizer and the filter element, which leads to a significant improvement in the separation effect of the filter element through the polarization phenomenon, and ensures its service life even if the filter element ages. An upstream grid element, which expediently serves as a counter-electrode for at least one electrode, ensures an improved electrostatic charging of the particles entrained in the air flow, whereby, in combination with the polarization effect, an improvement in the separation effect of the filter element can be achieved.

[0012] It is clear to the person skilled in the art that the mentioned ionization of the air flow means only the electrostatic charging of the gas molecules of the air and of the particles entrained in the air flow.

[0013] It is suitable that, in the operation of the air filter, for example, by means of a high voltage source, a first potential is applied or can be applied to at least one electrode, and a second potential different from the first potential is applied or can be applied to at least one counter electrode, filter layer and grid element. Thus, in the operation of the air filter, an electric field is established between the ionizer and the filter element, and the ionizer is composed of at least one electrode, counter electrode and grid element as mentioned above. Because the potential of the counter electrode is additionally present on the filter element, a polarization effect can be achieved in the filter element. This effect can ensure a significant increase in the separation effect of the filter element, even if the filter element is aged.

[0014] Furthermore, it can be provided that the first potential is the supply potential and the second potential is the counter potential. In particular, the reverse solution is conceivable, wherein the first potential is the counter potential and the second potential is the supply potential. The first potential can be a negative high voltage potential, wherein in this case the counter potential is a positive counter potential. Alternatively, it is conceivable that the first potential is a positive high voltage potential and the counter potential is a negative counter potential.

[0015] It is conveniently provided that, during operation of the air filter device, a negative or positive potential difference (voltage potential) is applied or can be applied between at least one electrode on the one hand and at least one counter-electrode, the filter layer and the grid element on the other hand. The potential difference mentioned is conveniently determined by the difference between the first potential and the second potential.

[0016] In particular, it can be provided that the voltage or potential difference is in the range of -5 kV to -11 kV, or preferably -7 kV. Thus, at least one electrode can generate a negative corona discharge, which leads to an improved ionization of particles carried in the air flow compared to a positive corona discharge, and thus to a better separation effect by the air filter. The air filter can still be designed and operated as follows, so that at least one electrode achieves a positive corona discharge in the air flow.

[0017] It can be conveniently provided that the ionizer has a first spacing in the range of 0 mm to 30 mm, preferably 7 mm, with the filter element arranged downstream. In addition, at least one electrode can have a second spacing in the range of 20 mm to 50 mm, preferably 30 mm, with the grille element arranged upstream. Thus, ionization is achieved in the air filter device, and the particles in the air flow are charged by ionization. In addition, a favorable polarization effect is thus produced in the filter element. These effects are combined to ensure a high degree of particle separation. At the same time, the air filter device is compactly constructed in the described area, so that the structural space dimensions of the air filter device required for use in a vehicle air conditioning device can be complied with. The present invention is particularly aware that if the spacing between the ionizer and the filter element is 7 mm and the spacing between the ionizer and the grille element is 30 mm, a better relationship between the improved particle separation effect on the one hand and the structural dimensions of the air filter device on the other hand can be adjusted.

[0018] Preferably, the grid element has a grid width in the range of 1 mm to 6 mm, and preferably 3 mm. In this case, the invention appropriately understands "grid width" as the clear distance between two adjacent grid nodes of the grid element. The grid element can also have a grid area in the range of 1x1 mm² to 6x6 mm², and preferably 3x3 mm². In this case, the grid area refers to the area size of the grid openings of the grid element. It can also be provided that the grid element is made of stainless steel for stable implementation.

[0019] It can further be arranged that the filter element has a layer for particle separation. The layer is suitably provided by a weakly conductive material or an electrically insulating material. In particular, the layer can form an electrostatic field.

[0020] It is suitable here that the layer (i.e. the dielectric layer) is arranged on the filter layer at the filter element inlet side facing the ionizer and the air flow. Thus, the dielectric layer is placed in front of the filter layer with respect to the air flow and is therefore flushed by air in front of the filter layer. The dielectric layer is preferably a particle separation layer of the filter element.

[0021] In addition, it can be provided that the filter layer has an activated carbon layer or is formed by an activated carbon layer. With the help of such a filter layer, harmful gases and unpleasant odors carried in the air flow can be reliably removed from the air flow. The activated carbon layer is preferably connected downstream of the dielectric layer with respect to the air flow.

[0022] Furthermore, it is expedient if the filter element is embodied in a pleated manner, ie is arranged in a folded manner.

[0023] With respect to at least one electrode and at least one counter-electrode, different designs are conceivable. However, it is advantageous that at least one electrode has a pointed (needle-shaped or conical) electrode body defining a central axis, and at least one counter-electrode has an annular or cylindrical counter-electrode body delimiting an internal volume. Here, the electrode body can be arranged with respect to the counter-electrode body so that the central axis of the electrode body is parallel to the central axis of the counter-electrode body and is preferably oriented coaxially. Here, the electrode body can be arranged completely or substantially completely in the internal volume of the counter-electrode body. In addition, the tip of the needle-shaped or conical electrode body can face the air flow. In addition, it may be appropriate that the diameter of the counter-electrode body is in the range of 40 mm to 90 mm, or preferably 50 mm. In addition, if the stable availability of at least one electrode and at least one counter-electrode should be ensured, it can be provided that both the electrode body and the counter-electrode body are made of stainless steel. In addition, the grid element used as the counter-electrode can also preferably be made of stainless steel.

[0024] Further preferably, the air filter device has two or more electrodes and two or more counter electrodes respectively assigned to the electrodes, wherein the electrodes are conductively connected to each other, and wherein the counter electrodes are conductively connected to each other. In addition, it can be provided that the air filter device has at least one other electrode and at least one other counter electrode assigned to at least one other electrode. At least one electrode and at least one other electrode are conductively connected to each other. In addition, at least one counter electrode and at least one other counter electrode can be conductively connected to each other. Therefore, the air filter device has an arrangement consisting of at least two electrodes and an arrangement consisting of at least two counter electrodes, which are respectively assigned to one of the at least two electrodes. It can also be provided that the air filter device has a large number of electrodes and a large number of counter electrodes, wherein the counter electrodes are conductively connected to each other, wherein the electrodes are conductively connected to each other, and wherein the counter electrodes are respectively assigned to the electrodes.

[0025] According to a further concept of the invention, a vehicle air conditioning system for a vehicle is provided, which is installed in the vehicle and is designed for air conditioning of the passenger compartment of the vehicle. It is important that it is equipped with at least one air filter device according to the above description. Thus, an advantageous vehicle air conditioning system is described, which, due to the at least one air filter device installed in the passenger compartment, can provide a vehicle interior atmosphere with a high air quality for a relatively long operating period.

[0026] In summary, it should be pointed out that the present invention preferably relates to an air filter device, through which the flow path of the air flow formed by air is guided. The air filter device has an ionizer arranged in the flow path and an electrostatic filter element arranged downstream of the ionizer in the flow path, so that the ionizer and the filter element can flow through. In addition, the ionizer has an electrode for generating a corona discharge that can be electrically connected to a high voltage source of the air filter device, a counter electrode assigned to the electrode, and a conductive grid element arranged upstream of the electrode in the current path, which grid element is preferably used as an additional counter electrode. It is important for the present invention that the counter electrode is electrically connected to the conductive surface filter layer and the grid element of the filter element. The present invention particularly relates to a vehicle air conditioning device having at least one such air filter device.

[0027] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated description of the figures with the aid of the drawings.

[0028] It goes without saying that the features mentioned above and those 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 protection of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Preferred embodiments of the present invention are shown in the drawings and are explained in detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0030] Figure 1 A simplified perspective view of a preferred embodiment of an air filter device is shown, and

[0031] Figure 2 The cross-sectional view shows Figure 1 Air filtration device. DETAILED DESCRIPTION

[0032] Figure 1 and Figure 2 A preferred simplified embodiment of an air filter device, which is designated overall by reference numeral 1 , is shown, which is preferably designed as a passenger compartment air filter device and is installed in a housing 3 of a vehicle air conditioning system 2 of a vehicle (not shown).

[0033] exist Figure 1 and Figure 2In the embodiment, air flows through the air filter device 1 in the direction indicated by the arrow 30. Specifically, the air is an air flow from outside air or circulating air or a mixed air consisting of outside air and circulating air, which is sucked from the environment surrounding the vehicle and guided into the passenger compartment, which is also not shown. The air flow carries unwanted particles, harmful gases and unpleasant odors, which are to be separated from the air flow by means of the air filter device 1. For this purpose, it is provided that the air filter device 1 has an ionizer 10 arranged in the flow path 30 for ionizing the air flow and a filter element 20 for filtering the air flow, which is electrostatically charged on the manufacturer's side and is arranged downstream of the ionizer 10 in the flow path 30. With the help of Figure 1 and Figure 2 It can be seen that the air flow flows completely through the ionizer 10 and the filter element 20 .

[0034] The ionizer 10 of the air filter device 1 has a plurality of electrodes 11 located in a common plane, each of which is designed to generate a corona discharge. The electrodes each have a needle-shaped or cone-shaped electrode body 12, which is Figure 1 and Figure 2 The electrode bodies 12 in the present case each define a central axis 13 in their respective main extension direction and also each have a tip 14 facing the air flow, see Figure 2 In addition, it is provided that the electrode 11 is provided with Figure 1 and Figure 2 The first electrical conductor 5 shown in FIG. 1 is connected to the air filter device 1 in Figure 1 and Figure 2 The high-voltage source 4 shown in FIG. 1 by a simple box is electrically connected. The high-voltage source 4 is designed to apply an electrical potential to the electrode 11 .

[0035] In addition to the electrode 11, the ionizer 10 also has a plurality of counter-electrodes 15, which are located in a common plane and are respectively assigned to the electrode 11. The counter-electrodes 15 each have an annular or hollow cylindrical counter-electrode body 16, which has a clear diameter 17 in the range of D=40 mm to D=90 mm or preferably D=50 mm. Furthermore, the counter-electrode body 16 each delimits an inner volume 26. For reasons of stability, the counter-electrode body 16, like the electrode 11, is also made of stainless steel. Figure 1 and Figure 2 It can be seen that the counter-electrode 15 and the electrode 11 are assigned to one another so that the electrode bodies 12 mentioned are each arranged centrally with respect to the counter-electrode body 16 and completely or substantially completely in the respective inner volume 26 of the counter-electrode body 16. In this case, the electrode bodies 12 are suitably oriented in the respective inner volume 26 so that their central axes 13 are parallel and in particular coaxial with respect to the central axis 35 defined by the counter-electrode body 16.

[0036] The ionizer 10 of the air filter device 1 also has a grid element 40 which is arranged upstream of the electrode 11 in the flow path 30 and which is flat in shape and made of a conductive material, such as stainless steel. The grid element has a mesh width in the range of 1 mm to 6 mm and preferably 3 mm, so that the grid element can be advantageously flowed through by the air flow in a fluid dynamic manner. In addition, the grid element acts as an additional counter-electrode, which ensures effective ionization of particles in the air flow.

[0037] The filter element 20 of the air filter device 1 can be pleated and / or integrally implemented. At present, the filter element has a layer structure including a conductive filter layer 21 and a dielectric layer 22 for particle separation. Other layers are also conceivable. The filter layer 21 can have an activated carbon layer or be formed entirely by an activated carbon layer. Suitably, the dielectric layer 22 is provided by a weakly conductive material or an electrically insulating material and is arranged on the filter layer 21 at the filter element inflow side 23 of the filter element 20 facing the ionizer 10 and the air flow. Thus, the dielectric layer 22 is pre-placed with respect to the air flow direction 30, and is therefore flushed by air before the filter layer 21.

[0038] The ionizer 10 is arranged relative to the filter element 20 in such a way that a first distance 36 in the range of 0 mm to 30 mm, preferably 7 mm, is provided between them.

[0039] Furthermore, the grid elements 40 are arranged relative to the electrode tips 14 in such a way that a second distance 41 ( H1 ) is provided between them in the range of H1 =20 mm to H1 =50 mm, preferably H1 =30 mm.

[0040] The minimum distance 44 (H2) between the counter electrode 15 and the electrode 11 in the direction of air flow (arrow 30) is equal to or greater than half the inner diameter of the electrode body 16, for example, the minimum distance is H2 = 20 mm to H2 = 45 mm, preferably H2 = 25 mm.

[0041] It is now important for the present invention that the counter electrode 15 is electrically conductively connected to the conductive filter layer 21 of the filter element 20 and the grid element 40 acting as an additional counter electrode by means of the second electrical conductor 6. It is therefore possible that, during the operation of the air filter device 1, the electrode 11 is loaded with a first potential 33 by means of the high voltage source 4, while a second potential 34 different from the first potential 33 is applied or can be applied to the counter electrode 15, the filter layer 21 and the grid element 40. For example. The first potential 33 can be a supply potential, and the second potential 34 can be a counter potential. The counter potential is currently achieved by connecting the second electrical conductor 6 to the counter potential point 7. As a result, a potential difference is preferably generated between the first potential 33 and the second potential 34. The potential difference can be in the range of -5 kV to -11 kV or preferably -7 kV.

[0042] This achieves that during the operation of the air filter device 1, an air flow flows through the air filter device 1, wherein undesirable particles, such as fine dust, harmful gases and unpleasant odors, are guided through the ionizer 10. The electrode 11 is loaded with a first potential 33, so that a potential difference of, for example, -7 kV is generated between the electrode 11 and the counter electrode 15, the filter layer 21 and the grid element 40. As a result, a corona discharge is generated in the air flow in the vicinity of the electrode tip 14, so that the gas molecules are ionized in an electrostatic manner. Subsequently, the ionized gas molecules combine with the particles carried in the air flow, so that they can also be seen to be electrostatically charged. The counter electrode 15, the filter layer 21 and the grid element 40 (all of which are in the reverse potential) form a reverse potential relative to the electrode 11. Therefore, during the operation of the air filter device 1, an electrostatic field is established between the electrode 11 and the filter element 20. This electrostatic field ensures the polarization of the filter element 20. Due to the corona discharge particle charge and the electrostatic polarization phenomenon in the filter element layer, this leads to an increase in the separation of charged particles.

Claims

1. An air filter device (1), in particular a cabin air filter device for a vehicle air conditioning system (2), - a flow path (30) of an air stream formed by air passing through the air filter device, - in, The air filter device (1) comprises an ionizer (10) arranged in the flow path (30) for ionizing an air flow and an electrostatically charged filter element (20) arranged in the flow path (30) downstream of the ionizer (10) for filtering the air flow, so that an air flow formed by air can flow through the ionizer (10) and the filter element (20). - wherein the ionizer (10) comprises at least one electrode (11) which is electrically or conductively connected to a high-voltage source (4) of the air filter device (1) for generating a corona discharge in the air flow, at least one counter-electrode (15) associated with the at least one electrode (11), and an electrically conductive and flat grid element (40) which is arranged upstream of the at least one electrode (11) in the current path (30), It is characterized in that The at least one counter electrode (15) is electrically conductively connected to the electrically conductive, flat filter layer (21) of the filter element (20) and to the grid element (40).

2. The air filter device (1) according to claim 1, characterized in that: - During operation of the air filter device (1), a first potential (33) is or can be applied to the at least one electrode (11), and a second potential (44) different from the first potential (33) is or can be applied to the at least one counter electrode (15), the filter layer (21) and the grid element (40).

3. The air filter device (1) according to claim 1 or 2, characterized in that: - The first potential (33) is the supply potential and the second potential is the counter potential (34) thereof, or vice versa.

4. The air filter device (1) according to any one of the preceding claims, characterized in that - During operation of the air filter device (1), a negative or positive potential difference is or can be applied between the at least one electrode (11) on the one hand and the at least one counter electrode (15) on the other hand, the filter layer (21) and the grid element (40).

5. The air filter device (1) according to claim 4, characterized in that: The negative potential difference is in the range of −5 kV to −11 kV or preferably −7 kV.

6. The air filter device (1) according to any one of the preceding claims, characterized in that The ionizer (10) has a first distance (36) from the filter element (20) arranged downstream in the range of 0 mm to 30 mm, preferably 7 mm, and / or The electrode (11) has a second distance (41) from the grid element (40) arranged upstream in the range of 20 mm to 50 mm, preferably 30 mm.

7. The air filter device (1) according to any one of the preceding claims, characterized in that The filter element (20) has a dielectric layer (22).

8. The air filter device (1) according to claim 7, characterized in that: The dielectric layer (22) is arranged on the filter layer (21) at a filter element inflow side (23) of the filter element (20) facing the ionizer (10) and the air flow.

9. The air filter device (1) according to any one of the preceding claims, characterized in that The filter layer (21) comprises an activated carbon layer or is formed by an activated carbon layer.

10. The air filter device (1) according to any one of the preceding claims, characterized in that - the at least one electrode (11) has a needle-shaped or cone-shaped electrode body (12) defining a central axis (13), - the at least one counter-electrode (15) has a counter-electrode body (16) in the form of an annular or hollow cylinder which delimits an inner volume (26), - wherein the electrode body (12) is arranged relative to the counter-electrode body (16) in such a way that the central axis (13) of the electrode body (12) is parallel and preferably coaxial with the central axis (35) of the counter-electrode body (16), - wherein the electrode body (12) is arranged completely or substantially completely in the inner volume (26) of the counter-electrode body (16), and - wherein the tip (14) of the needle-shaped or cone-shaped electrode body (12) faces the air flow.

11. The air filter device (1) according to any one of the preceding claims, characterized in that - two or more electrodes (11) and two or more counter electrodes (15) respectively associated with the electrodes (11) are provided, - wherein the electrodes (11) are electrically conductively connected to one another, - wherein the counter electrodes (15) are electrically conductively connected to one another. 12 . A vehicle air conditioning system ( 2 ) of a vehicle, comprising at least one air filter device ( 1 ) according to claim 1 .

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