Air filtering device and vehicle air-conditioning equipment equipped with air filtering device

Abstract

The invention relates to an air filter device and a vehicle air conditioning system equipped with the air filter device. A flow path (32) of an air flow (30) from air passes through the air filter device (1), having an ionizer (10) arranged in the flow path and an electrostatically charged filter element (20) arranged downstream of the ionizer in the flow path (32) for filtering the air flow (30), such that the air flow (30) from air can flow through the ionizer (10) and the filter element (20), the ionizer (10) has an electrode (11), which is connected or can be connected in an electrically conductive manner to a high-voltage source (4) of the air filter device (1), for generating a corona discharge in the air flow (30), and a counter electrode (15), which is associated with at least one electrode (11). The counter electrode (15) is connected in an electrically conductive manner to an electrically conductive flat filter layer (21) of the filter element (20).

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 aforementioned type is known from WO 2020 263 171 A1. Other 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 aforementioned type are intended for cleaning the air of impurities such as fine dust, toxic gases (hydrocarbons, nitrogen oxides) and unpleasant odors (ammonia, trimethylamine, hydrogen sulfide, etc.). They are used in particular in vehicle air conditioning systems of vehicles, where they clean the outside air introduced from the environment into the passenger compartment of the vehicle. This makes it possible to provide a pleasant, healthy air climate and a high air quality in the passenger compartment.

[0004] Urban environments are a challenge for such air filters. Under certain weather conditions, the outside air there can have unusually high levels of fine dust pollution, which can be harmful to health. For example, in large cities, it is known that the daily average observed fine dust pollution exceeds the daily average of 15 μg / m3 recommended by the World Health Organization (WHO). 3 PM 2.5 These conditions place high demands on air filter units, especially in such urban environments, which should be able to ensure a high filter performance (separation rate) for the corresponding fine dust particles in the longest possible, maintenance-free operation.

[0005] In order to achieve this, manufacturers of corresponding air filter devices have already begun to apply static electricity to the filter elements installed in the air filter devices during their manufacturing process. As a result, such filter elements have an electrostatic field, through which particles carried in the external air (which are often also electrostatically charged) can be electrostatically charged, attracted and deposited on the filter element if necessary. Through this so-called electrostatic separation, for example, the smallest particles, especially dust particles with a size of <0.3μm, can be reliably separated from the air.

[0006] Unfortunately, the static electricity applied to the filter element becomes weaker over time, especially as the filter element ages and / or as contamination on the filter element increases. As a result, the specific gravity of the electrostatic separation decreases.

[0007] In order to counteract the reduction of the static charge on the filter element, ionizers are used in known air filter devices. They charge the gas molecules of the outside air with static electricity by generating a negative corona discharge or a positive corona discharge. The ionized gas molecules then combine with the particles carried in the air flow from the outside air, thereby improving the electrostatic separation by the filter element. However, these current air filter devices can no longer meet the requirements, in particular with regard to the required filter performance, after more or less long periods of operation. As a result, it is necessary to maintain the filter element in advance and, if necessary, replace the filter element. Summary of the invention

[0008] The object of the present invention is therefore to provide an improved or at least a different 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] It is known in the art that the filter performance of the filter element and the service life of the filter element can be increased by improving the polarization of the air filter device.

[0011] Therefore, an air filter device is proposed, in particular a vehicle cabin air filter device for a vehicle air conditioning device, wherein the flow path of the air flow from the air passes through the air filter device. The air filter device has an ionizer arranged in the flow path for ionizing the air flow, and an electrostatic filter element arranged downstream of the ionizer in the flow path for filtering the air flow, so that the air flow from the air can flow through the ionizer and the filter element. According to an appropriate manner, no other components are arranged upstream of the ionizer in the flow path. In addition, it is provided that the ionizer has at least one electrode connected to or can be connected to the high-voltage source of the air filter device in an electrically conductive manner for generating corona discharge in the air flow, and at least one counter electrode assigned to at least one electrode. Importantly, at least one counter electrode is connected to the electrically conductive surface filter layer of the filter element in an electrically conductive manner. Thus, the air filter device is arranged so that during the operation of the air filter device, a polarization effect can be formed between the ionizer and the filter element, and even if the filter element has been relatively obviously aged, the polarization effect also significantly improves the filtering performance of the filter element and the service life of the filter element.

[0012] Here, those skilled in the art understand that the ionization of the airflow refers to the static electricity of the gas molecules of the air and the particles carried in the airflow.

[0013] Suitably, during operation of the air filter, a first potential can be applied or applied to at least one electrode, for example in combination with a high voltage source, and a second potential different from the first potential can be applied or applied to at least one counter-electrode and the filter layer. Thus, during operation of the air filter, an electrostatic field is established between the ionizer and the filter element, which in particular exerts a polarizing effect on the ions generated in the airflow during the corona discharge and other particles carried in the air. This effect can significantly increase the separation of the filter element even if the filter element has aged.

[0014] In addition, it can be provided that the first potential is the supply potential and the second potential is the matching potential. In particular, an inverted solution is conceivable, wherein the first potential is the matching potential and the second potential is the supply potential. The matching potential can be obtained, for example, by connecting at least one counter electrode and the filter layer of the filter element to ground (for example, grounding). The matching potential can in particular be a zero potential.

[0015] According to suitable provisions, during the operation of the air filter device, a positive or negative 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 and the filter layer on the other hand. The potential difference is determined in a suitable manner by the difference between the first potential and the second potential.

[0016] In particular, it can be provided that the negative potential difference is in the range of -5 kV to -15 kV or preferably -7 kV or in particular -11 kV. Thus, at least one electrode can realize a negative corona discharge, which leads to an improved ionization of particles carried in the airflow compared to a positive corona discharge, and thus leads to a better separation rate of the air filter. However, the air filter can be arranged and operated as follows, that is, at least one electrode in the airflow realizes a positive corona discharge.

[0017] It can be provided in a suitable manner that the ion generator has a first spacing relative to the filter element arranged downstream, which is in the range of 0 mm to 30 mm, preferably 7 mm. If the spacing between the ion generator and the filter element is in the range of 0 mm to 30 mm, a relatively large volume of electrostatic field can be provided between the ion generator and the filter element, so that the polarization effect can be maintained for a relatively long time, and thus a good separation effect can be obtained. At the same time, the air filter device is relatively compactly constructed in a given area, so that the size of the air filter device with respect to the installation space required in the vehicle air conditioning device can be maintained. The present invention particularly recognizes that if the spacing between the ion generator and the filter element is 7 mm, an optimized ratio can be set between the polarization effect achievable by the electrostatic field on the one hand and the structural size of the air filter device on the other hand.

[0018] It can also be provided in an appropriate manner that the filter element has a dielectric layer for particle separation. The dielectric layer is suitably made of a weakly conductive material or an electrically insulating material. In particular, it can form an electrostatic field.

[0019] It is suitable here that the dielectric layer is arranged on the filter layer on the filter element inflow side facing the ionizer and the airflow of the filter element. Thus, the dielectric layer is located upstream of the filter layer with respect to the airflow, and is thus washed by air before the filter layer. The dielectric layer can be a part of the filter layer, or the whole filter layer can be the dielectric layer itself. In addition, it can be provided that the dielectric layer is arranged on the filter layer on the filter element outflow side facing away from the ionizer and the airflow and away from the filter element inflow side of the filter element. In addition, it can be provided that the dielectric layer forms a filter layer for separating particles or forms a dielectric layer for the filter layer for separation.

[0020] Furthermore, it can be provided that the filter layer comprises an electrically conductive layer, in particular an activated carbon layer, or is formed from an electrically conductive layer, in particular an activated carbon layer. In combination with such a filter layer, harmful gases (such as hydrocarbons or nitrogen oxides) and unpleasant odors (such as ammonia, trimethylamine, hydrogen sulfide, etc.) carried in the air flow can be reliably removed from the air flow.

[0021] Furthermore, it is expedient if the filter element is pleated, ie arranged in folds.

[0022] Different designs are conceivable with respect to the at least one electrode and the at least one counter-electrode. It is advantageous, however, that at least one electrode has a needle-shaped or conical electrode body defining a central axis, and that at least one counter-electrode has an annular or cylindrical counter-electrode body delimiting an internal volume. The electrode body can be arranged with respect to the counter-electrode body in such a way that the central axis of the electrode body is parallel and preferably coaxial with respect to the central axis of the counter-electrode body. Here, the electrode body can be arranged approximately completely or completely in the internal volume of the counter-electrode body, and the tip of the needle-shaped or conical electrode body faces the gas flow. Furthermore, it may be appropriate that the diameter of the counter-electrode body is in the range of 40 mm to 90 mm or preferably is 50 mm. Furthermore, if the inexpensive availability of the at least one electrode and the at least one counter-electrode should be ensured, it may be provided that the electrode body and the counter-electrode body are made of stainless steel.

[0023] It is further appropriate that the air filter device has two or more electrodes and two or more counter-electrodes respectively assigned to the electrodes, wherein the electrodes are connected to each other in an electrically conductive manner, and wherein the counter-electrodes are connected to each other in an electrically conductive manner. 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. Here, at least one electrode and at least one other electrode are connected to each other in an electrically conductive manner. In addition, at least one counter-electrode and at least one other counter-electrode are connected to each other in an electrically conductive manner. Therefore, the air filter device has a system consisting of at least two electrodes and a system consisting of at least two counter-electrodes, and the counter-electrodes are respectively assigned to one of the at least two electrodes. It can also be provided that the air filter device has a plurality of electrodes and a plurality of counter-electrodes, wherein the counter-electrodes are respectively connected to each other in an electrically conductive manner, wherein the electrodes are respectively connected to each other in an electrically conductive manner, and wherein the counter-electrode is assigned to each electrode.

[0024] According to another concept of the present invention, a vehicle air conditioning system is provided for a vehicle, which is installed in the vehicle and is provided for air conditioning 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. This provides an advantageous vehicle air conditioning system, which, due to the at least one air filter device installed in the passenger compartment, can provide a room climate with high air quality over a relatively long operating time.

[0025] In summary, it should be observed that the present invention preferably relates to an air filter device, through which the flow path of an air flow from air passes, wherein the air filter device has an ionizer arranged in the flow path and an electrostatically charged filter element arranged in the flow path downstream of the ionizer for filtering the air flow, so that the air flow from the air can flow through the ionizer and the filter element, wherein the ionizer has an electrode that is or can be connected in an electrically conductive manner to a high-voltage source of the air filter device for generating a corona discharge in the air flow, and a counter-electrode assigned to at least one of the electrodes. It is important for the present invention that the counter-electrode is connected in an electrically conductive manner to a conductive surface filter layer of the filter element. The present invention particularly relates to a vehicle air conditioning system for a vehicle, which is equipped with at least one such air filter device.

[0026] Further important features and advantages of the invention are apparent from the dependent claims, the drawings and the associated description of the figures in conjunction with the drawings.

[0027] It is understood that the features mentioned above and those yet to be explained below can be used not only in the respectively given combination but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Preferred exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals designate identical or similar or functionally identical components.

[0029] The figure shows respectively:

[0030] Figure 1 is a simplified perspective view of a preferred embodiment of an air filtration device;

[0031] Figure 2 is based on Figure 1 A cross-sectional view of an air filter device. Specific implementation plan

[0032] Figure 1 and Figure 2 A preferred and greatly simplified embodiment of an air filter device, designated overall by reference numeral 1 , is shown, which is preferably designed as a vehicle cabin 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 2 As can be seen in Figure 1 and Figure 2 The airflow 30 from the air indicated by the arrow is only Figure 2 The flow path 32 drawn in the figure passes through the air filter device 1. Specifically, the air flow 30 comes from the outside air, which is sucked in from the vehicle's surroundings and introduced into the passenger compartment (also not shown). The air flow 30 from the outside air, especially in urban environments, carries undesirable particles, such as dust, which should be separated from the air flow 30 from the outside air in conjunction with 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 32 for ionizing the air flow 30 and a filter element 20 electrostatically charged on the manufacturer's side, arranged in the flow path 32 downstream of the ionizer 10, for filtering the air flow 30. In conjunction with Figure 1 and Figure 2 It can be seen that the air flow 30 from the outside air flows completely through the ionizer 10 and the filter element 20. In a suitable manner, the gases in the air flow 30 are ionized by means of the ionizer 10, wherein these ionized gases then attach to the approximately 10 4 The charged particles are then responsible for increasing the particle separation in the filter element 20 downstream, as will be explained below.

[0034] The ion generator 10 of the air filter device 1 has a plurality of electrodes 11 located in a common plane, which are respectively arranged to generate a positive corona discharge or a negative corona discharge in the air flow 30. Figure 1 and Figure 2 The electrode bodies 12 are needle-shaped or cone-shaped and are made of stainless steel and are represented by simple triangles. Here, the electrode bodies 12 define a central axis 13 in their respective main extension directions and also have a tip 14 facing the gas flow 30, see Figure 2 The corresponding electrode 11 can be provided in large quantities at low cost. In addition, it is provided that the electrode 11 is combined with Figure 1 and Figure 2 The first electrical conductor 5 shown is connected to the air filter device 1 Figure 1 and Figure 2 A high voltage source 4, which is represented by a simple box in the figure, is connected in an electrically conductive manner. The high voltage source 4 is provided for applying a relatively high potential to the electrode 11.

[0035] In addition to the electrodes 11, the ion generator 10 also has a plurality of counter-electrodes 15, which are located in a common plane and are assigned to each electrode 11. The counter-electrodes 15 each have a counter-electrode body 16 in the form of a ring or hollow cylinder, whose inner diameter 17 is in the range of 40 mm to 90 mm or preferably 50 mm. In addition, the counter-electrode body 16 respectively delimits an inner volume 26. The counter-electrode body 16 is also made of stainless steel for cost reasons in order to improve stability, just like the electrode 11. Figure 1 and Figure 2 1 and 2, it can be seen that the counter-electrode 15 and the electrode 11 are assigned to one another in such a way that the electrode bodies 12 are each centered with respect to the counter-electrode body 16 and are arranged approximately completely or completely within the respective interior volume 26 of the counter-electrode body 16. In this case, the electrode bodies 12 in the respective interior volume 26 are oriented in such a way 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 filter element 20 of the air filter device 1 can be pleated and / or one-piece. Here, it has a layer structure, which includes a conductive surface filter layer 21 and a dielectric layer 22 for particle separation. Other layers are conceivable. The filter layer 21 can have an activated carbon layer or be completely composed of an activated carbon layer. The dielectric layer 22 is provided by a weakly conductive or electrically insulating material in an appropriate manner, and it is further appropriate to arrange it on the filter layer 21 on the filter element inflow side of the filter element 20 facing the ion generator 10 and the air flow 30. As a result, the dielectric layer 22 is located upstream of the filter layer 21 with respect to the air flow 30, and is thus flushed by air before the filter layer 21. The dielectric layer 22 is or preferably forms a particle separation layer, especially the filter layer 21. The known hybrid filter is basically composed of two separation layers, such as a polymer fiber layer for separating particles and an activated carbon layer for separating gases. The activated carbon layer can be electrically contacted with the counter electrode, because the activated carbon has a high electrical conductivity. The dielectric layer 22 can also be arranged additionally or alternatively on the filter layer 21 on the filter element outflow side of the filter element 20 facing away from the ionizer 10 and the gas flow 30 and facing away from the filter element inflow side.

[0037] The ionizer 10 is arranged relative to the filter element 20 in such a way that a first distance 36 is provided between them, which first distance 36 is in the range of 0 mm to 30 mm, preferably 7 mm.

[0038] The essence of the present invention is now that the counter electrode 15 is connected to the conductive filter layer 21 of the filter element 20 in an electrically conductive manner via the second electrically conductive conductor 6. Thus, the electrode 11 is loaded with the first potential 33 in combination with the high voltage source 4 during the operation of the air filter device 1, and at the same time, a second potential 34 different from the first potential 33 can be applied or applied to the counter electrode 15 and the filter layer 21. For example, the first potential 33 can be a supply potential, and the second potential 34 can be a matching potential. The latter is implemented here as follows, that is, the second electrical conductor 6 is connected to a point 7, which is grounded, for example. Thus, a negative potential difference is preferably obtained between the first potential 33 and the second potential 34. It can be located in the range of -5kV to -15kV, or preferably just at -7kV and especially -11kV.

[0039] The following purpose is achieved thereby: during the operation of the air filter device 1, an air flow 30 from the outside air flows through the air filter device 1, wherein undesirable particles such as fine dust, harmful gases and unpleasant odors are guided through the electrode 11. As described above, they are loaded with a first potential 33, thereby obtaining a potential difference of, for example, -7 kV between the electrode 11 and the counter electrode 15 and the filter layer 21. Thus, a corona discharge is generated in the air flow 30 within a close range around the electrode 11, so that the gas molecules of the air flow 30 are electrostatically charged (ionized). Then, the ionized gas molecules are combined with the undesirable particles carried in the air flow 30, so that they can also be regarded as electrostatically charged (ionized). The counter electrode 15 and the filter layer 21, both located at the matching potential, form a matching potential relative to the electrode 11. Thus, during the operation of the air filter device 1, an electrostatic field is established between the electrode 11 and the filter layer 21, which supports the electrostatic charging of the filter element 20 and / or applies a polarization effect, in particular, to the particles carried by the electrostatic charge. This makes it possible to achieve a preferred separation of particles even in the event of filter aging.

[0040] It is expediently provided that the electrode 11 is held by the electrical conductor 5, in such a way that the electrical conductor 5 forms the carrier element. Further expediently, Figure 1 and Figure 2 The ion generator 10 shown can only be operated when the electric conductor 5 is installed before the electrode 11, for example, the electric conductor 5 is arranged before the ion generator 10 in the air flow direction 30. In this construction mode, the spacing between the ion generator 10 and the filter element 20 can preferably be 7 mm. If necessary, the electric conductor 5 can be arranged between the ionizer 10 and the filter element 20, that is, in the area below the ionizer 10 and the surface of the filter layer 21. In a suitable manner, in this construction mode, an electric polarization field can be generated between the ionizer 10 and the filter surface. Further suitably, in this construction mode, an electric polarization field can be generated between the electric conductor 5 and the filter surface. Here, in a suitable manner, no electric field is generated between the electrode 11 and the filter surface.

Claims

1. An air filter device (1), in particular a vehicle cabin air filter device for a vehicle air conditioning system (2), through which a flow path (32) of an air flow (30) from the air passes, - in, The air filter device (1) comprises an ionizer (10) arranged in a flow path (32) for ionizing the airflow (30), in particular ionizing particles in the airflow, and an electrostatically charged filter element (20) arranged downstream of the ionizer (10) in the flow path (32) for filtering the airflow (30), so that the airflow (30) from the air can flow through the ionizer (10) and the filter element (20). - wherein the ion generator (10) comprises at least one electrode (11) which is or can be connected in an electrically conductive manner to a high-voltage source (4) of the air filter device (1) for generating a corona discharge in the air flow (30), and at least one counter-electrode (15) associated with the at least one electrode (11), Features The at least one counter electrode (15) is electrically conductively connected to the electrically conductive flat filter layer (21) of the filter element (20).

2. The air filter device (1) according to claim 1, It is characterized in that - During operation of the air filter device (1), a first potential (33) can be or is applied to the at least one electrode (11), and a second potential (34) different from the first potential (33) can be or is applied to the at least one counter electrode (15) and the filter layer (21).

3. The air filter device (1) according to claim 1 or 2, It is characterized in that The first potential (33) forms a supply potential, and the second potential (34) forms a matching potential relative to the supply potential.

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

5. The air filter device (1) according to claim 4, It is characterized in that - The negative potential difference is in the range of -5 kV to -15 kV or preferably -7 kV.

6. Air filter device (1) according to one of the preceding claims, It is characterized in that The ionizer (10) has a first distance (36) relative to the filter element (20) arranged downstream, the first distance being in the range of 0 mm to 30 mm, preferably 7 mm.

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

8. The air filter device (1) according to claim 7, It is characterized in that - the dielectric layer (22) is arranged on the filter layer (21) on the filter element inflow side of the filter element (20) facing the ionizer (10) and the air flow (30), and / or The dielectric layer (22) is arranged on the filter layer (21) on the filter element outflow side of the filter element (20) facing away from the ionizer (10) and the air flow (30).

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

10. The air filter device (1) according to one of the preceding claims, It is 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 an annular or cylindrical counter-electrode body (16) 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 respect to the central axis (35) of the counter-electrode body (16), - wherein the electrode body (12) is arranged substantially completely or 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 (30).

11. The air filter device (1) according to one of the preceding claims, It is characterized in that - providing two or more electrodes (11) and two or more counter-electrodes (15) which are to be respectively assigned to the electrodes (11), - wherein the electrodes (11) are connected to one another in an electrically conductive manner, - wherein the counter electrodes (15) are connected to one another in an electrically conductive manner. 12 . A vehicle air conditioning system ( 2 ) of a vehicle, which is equipped with at least one air filter device ( 1 ) according to one of the preceding claims.

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