Filter housing, filter insert, and filter unit comprising a polarisation filter and an electrostatic precipitator

Abstract

The invention relates to a filter unit (1) comprising a power supply (20), a spray electrode (15), and a filter medium (115) located between a first electrode (110) and a second electrode (120), wherein the first electrode (110) is arranged between the spray electrode (15) and the second electrode (120), the power supply (20) has a spray electrode output (28) and an additional output (29), and the power supply (20) is designed to provide an ionisation current and to supply a voltage between the spray electrode output (28) and the additional output (29), the filter unit being particularly cost-effective to manufacture if the first electrode (110) and the second electrode (120) are connected, in parallel to one another, to the additional output (29) of the power supply (20).

Description

[0001] Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 1 / 27 July 19, 2024 Filter housing, filter insert, and filter unit with polarization filter and electrostatic precipitator Technical field The invention relates to a filter system, a filter housing, and a filter insert for a gas filter. State of the art An electrical polarization filter is known from US 2006 / 137527 A1. The polarization filter has a dielectric filter medium that, like a sieve, retains dust particles as they flow through the filter medium. A gas-permeable electrode is arranged on each of the upstream and downstream sides of the filter medium. A high voltage is applied between these electrodes (typically in the range of 0.5 to 1.5 V DC), which merely polarizes the dielectric; in electrical terms, the electrical polarization filter is a capacitor. The polarization of the dielectric filter medium increases dust separation (cf.Frank Jordan, "Investigations into the particle separation behavior of submicron particles in fiber filters in an electric field," dissertation, University of Duisburg (Germany), 2001. These electrical polarization filters are to be distinguished from so-called electrostatic precipitators, which are often also referred to as electrostatic filters (although they are not filters—only sieving gas purification is referred to as filtration herein). These filters are based on the fact that dust particles are first electrostatically charged and then deposited on a collecting electrode. Electrostatic precipitators have a spray electrode and a collecting electrode. Dust particles in the gas are charged by the charge carriers emitted by the scattering electrode and then deposited on the collecting electrode by Coulomb attraction. Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 2 / 27 19.07.The ionization voltage between the discharge electrode and the collecting electrode is typically between 5 kV and 8 kV, depending on their distance from each other, and the corresponding current, depending on the size and number of electrodes, is typically between about 10 µ^ and about 10^^, with 10 µ^ only being sufficient for relatively small systems, e.g., for incubators or the like, and 10^^ (or more) flowing in large industrial systems. It has been proposed (cf. US 2008 / 0190772 A1) to combine these two gas purification mechanisms, i.e., to first subject a gas stream to electrostatic precipitation and then to purify it with an electrical polarization filter. For this purpose, two different high-voltage sources must be provided: One high-voltage source that supplies the ionization voltage (typically about 5^^ to about 8^^) and another high-voltage source that supplies the polarization voltage (typically about 0.5^^ to about 1.5^^).Description of the invention The object of the invention is to reduce the costs for air purification using an electrostatic precipitator and an electrical polarization filter. This object is achieved by a filter unit according to claim 1 and a filter housing according to claim 3. Advantageous embodiments of the invention are specified in the subclaims. Preferably, the filter unit has at least one power supply, at least one spray electrode and at least one filter medium which is arranged between a first and a second electrode of the filter unit. The filter medium is therefore preferably located in a gap formed by the first and the second electrode. Preferably, the filter medium closes the gap, ie the filter medium can fill the gap. In a Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 3 / 27 July 19.In one example, the first electrode, the filter medium, and the second electrode form a laminate and / or a sandwich structure. In one example, the first electrode can be applied to a first side of the filter medium, and the second electrode can be applied to the second side of the filter medium, with the first side and the second side preferably being two sides of the filter medium facing away from one another. As already described at the beginning, the first electrode and the second electrode are preferably fluid-permeable. The filter medium can be one-piece, but it can also consist of several layers. A typical example of a filter medium is pleated filter paper. In simple terms, the filter medium is an insulator, i.e. a dielectric. The filter medium can have a plurality of (if necessary)microscopically small passages (“pores”) through which a fluid can flow from the first side to the second side, wherein particles larger than the pores are retained by the filter medium. The filter medium can in particular comprise activated carbon, either as a separate activated carbon layer or activated carbon particles integrated into a filter paper or a filter mat. In a particularly preferred embodiment, the second electrode comprises and / or consists of activated carbon. The activated carbon retains ozone produced during electrostatic deposition and simultaneously serves as a polarization electrode. A metallic grid electrode and / or a conductive plastic grid, for example, which would otherwise be used as a second electrode, can be omitted or at least made smaller, thereby correspondingly reducing resource consumption.The first electrode is preferably arranged spatially between the spray electrode and the second electrode. If the filter unit is arranged in a fluid channel, a fluid flow could consequently flow from an inlet of the fluid channel, preferably from the spray electrode to the first electrode, then through the filter medium and to the second electrode, to an outlet of the fluid channel. The filter unit can be designed as a fluid channel and / or integrated into a Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 4 / 27 July 19, 2024 fluid channel and / or have a fluid channel. For example, the fluid channel can be formed by a filter housing. There is preferably a distance between the spray electrode and the first electrode, ie the first electrode is preferably spaced from the spray electrode. The power supply preferably has a spray electrode output and a further output.In addition, the power supply is preferably configured to provide a (preferably preset) ionization current ^. ^^^ (ie the power supply is preferably a constant current source), as well as a (corresponding) voltage ^ ^^^between the spray electrode output and the further output. As the name suggests, the spray electrode output is preferably connected to the spray electrode or at least configured to be connected to at least one spray electrode. Particularly preferably, the first electrode and the second electrode are connected in parallel to each other to the further output of the power supply. Consequently, there is a first electrically conductive connection between the first electrode and the further output and a second electrically conductive connection between the second electrode and the further output, i.e., the first electrode and second electrode are connected to the same output of the power supply. Nevertheless, a voltage exists between the two electrodes of the polarization filter (i.e., between the first electrode and the second electrode) during operation. ^,^ on: The ionization current ^ ^^^flows from the spray electrode to the first electrode, whereby particles in the fluid stream are deposited at the first or also at the spray electrode. In addition, a voltage ^ is applied at the connection between the first electrode and the further output. ^,^ because this connection has a resistance greater than zero in practice. However, no voltage drops between the second electrode and the connection to the further output during operation, since no current flows through the second connection, ie only one power supply is sufficient to generate both an ionization voltage and an ionization voltage. ^^^ and a corresponding ionization current ^ ^^^ to provide as well as a polarization voltage. The polarization voltage ^ ^,^ can be caused by a resistor ^ ^between the first electrode and the other connection. For example, if the ionization current is ^ ^^^ e.g. ^ ^^^ = 0.05^^ and the resistance ^ ^ = 20^Ω the polarization voltage is ^ ^,^ = ^ ^^^ ⋅ ^ ^ = 1^^. This numerical example is for illustrative purposes only, the resistance ^ ^ is connected to the polarization filter (ie its design-specific polarization voltage) and the ionization current ^ ^^^ of the electrostatic precipitator. For smaller ionization currents, correspondingly larger resistances are necessary to achieve a given polarization voltage ^ ^,^ Based on the typical ionization currents given in the introduction (10^^ ≤ ^ ^^^ ≤ 10^^) results in setting a polarization voltage ^ ^,^ a resistance ^ ^ between 100^Ω ≥ ^ ^ When increasing or decreasing the specified polarization voltage ^ ^,^ the resistance increases ^ ^ proportional, ie Starting from a typical polarization voltage range of 0.5^^ to 1.5^^ (ie0.5^^ ≤ ^ ^,^ ≤ 1.5^^) results in 150^Ω ≥ ^ ^ ≥ 0.05^Ω. For very small polarization voltages of e.g. only 0.1KV, the lower limit of ^ ^ a value of 0.01^Ω, Due to the same technical connection, a filter housing which has at least one power supply, at least one spray electrode and at least one filter receptacle for a filter insert offers the same advantage as the filter unit. The filter receptacle is preferably configured to receive a filter insert with a filter element, wherein the filter element is arranged between a first electrode and a second electrode. The first and the second electrode can be part of the filter element, but also part of the filter housing. The only important thing is that the filter element is arranged between the first electrode and the second electrode during operation. The filter housing therefore has a first connection contact for the first electrode and a second connection contact for the second electrode or only exactly one connection contact for both electrodes.The power supply preferably has a discharge electrode output and another output. Furthermore, the power supply is preferably configured to provide an ionization current. ^^^ and a voltage ^ ^^^ between the discharge electrode output and the further output. As already described, the power supply is preferably a constant current source, ie during operation the voltage is varied so that a desired current (ie the ionization current ^ ^^^ ) flows between the spray electrode output and the further output. As can already be seen, the spray electrode output is preferably connected to the spray electrode. Preferably, the first connection contact and the second connection contact are connected in parallel to each other to the further output of the power supply. Particularly preferably, the first connection contact is connected via a first resistor ^ ^connected to the other output. Preferably, the second terminal is connected in parallel to the first resistor ^ ^ connected to the other output. This connection can include a second resistor ^ ^ , for which the above-described applies accordingly. For both the filter unit and the filter housing, it is preferable if the voltage drop ^ ^^ = ^ ^^^ ⋅ ^ ^ at the first resistance ^ ^ applies: ^ ^^ ≥ ^ ^ ^ ^ ^^ with ^ ^ ^ ^ ^^ / ^ ∈ {100, 300, 500, 700, 900, 1000, 1200, 1500}. The voltage drop across the first resistor ^ ^^ corresponds to the voltage ^ ^,^ between the first electrode and the second electrode, or the corresponding terminals. Consequently, the polarization voltage ^ '^( = ^ ^,^very Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 7 / 27 19.07.2024 simple, namely by the appropriate dimensioning of the resistor ^ ^ Preferably, the voltage drop is ^ ^^ at the first resistance ^ ^ between 50% and 99% of the breakdown voltage ^ ^ ) ^ of the filter element, i.e. ⋅ * ^ ⋅ ^ ^ ) ^ ≤ ^ ^^ ≤ * ^ ⋅ ^ ^ ) ^ , where * ^ ∈ B, * ^ ∈ B , β ^ ≤ * ^ and Β = {0.99; 0.975; 0.95; 0.8; 0.75; 0.7; 0.65; 0.6; 0.55; 0.50}. Preferably, the second electrode and / or the second terminal contact is parallel to the resistor ^ ^ connected to the other output. This increases operational reliability. This is especially true if the second electrode is connected via a resistor ^ ^ with the further output (parallel to the resistor ^ ^) is connected. The resistance ^ ^ makes it difficult for the dielectric filter medium, also called the filter element, to break down. Preferably, the resistance is ^ ^ therefore high resistance, particularly preferred is the resistance ^ ^ greater than or equal to the resistance ^ ^ (ie preferably ^ ^ ≥ ^ ^ ), because then an undesired breakdown is particularly reliably avoided or at least quickly extinguished, since the current path from the first electrode to the further output in the then in comparison also current path through the dielectric, the second electrode and the resistor ^ ^ has a lower resistance. The relation ^ ^ ≥ ^ ^ is not a necessary condition because the resistance ^ ^ in the current path to be avoided is only a partial resistance. In practice, even smaller values ​​for ^ ^ the desired technical effect, e.g. ^ ^ ≥ 0.75 ⋅ ^ ^. More generally, it is preferred if ^ ^ ≥ 0 ⋅ ^ ^ satisfies, where 0 ∈ A, A = { 0.75; 0.8; 0.9; 1; 1.5; 2; 2.5 } , dh0 can take any value of the quantity A, with larger values ​​being preferred. Preferably, the second electrode and / or the second terminal contact is connected via a second resistor ^ ^ connected to the further output and the first electrode parallel to the second resistor ^ ^connected to the further Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 8 / 27 July 19, 2024 output. As already described, this can increase operational reliability. A filter insert can be arranged in the filter receptacle of the filter housing, wherein the filter insert has at least one filter medium and wherein the filter medium is arranged between the first and the second electrode. These two electrodes can be part of the filter insert or also part of the filter housing. The first electrode is preferably connected to the further output via the first connection contact. The second electrode is preferably connected to the further output via the second connection contact. The first electrode is preferably arranged between the spray electrode and the filter medium and / or between the spray electrode and the second electrode.The invention also relates to a filter insert with a preferred flow direction, wherein the filter insert preferably has a first electrode, a second electrode, and an electrical mating contact. The mating contact is preferably configured such that, when the filter insert is inserted, it electrically contacts, preferably detachably contacts, a connection contact of a filter housing. Preferably, a dielectric filter medium is arranged between the first electrode and the second electrode, thereby forming a polarization filter. Preferably, the first electrode is electrically conductively connected to the mating contact via a first electrically conductive connection. Particularly preferably, the second electrode is electrically conductively connected to the mating contact via a second electrically conductive connection, wherein the first and second electrically conductive connections are connected in parallel to one another.Alternatively, the filter insert can also have only one connection contact, to which the two electrodes are connected in parallel. The resistance ^ is preferably connected between the first electrode and the one connection contact. ^ and / or between the second electrode and the one connection contact is preferably the resistance ^ ^ . One connection contact then serves as an additional power supply connection "routed" to the filter insert and is therefore at least configured to be connected to the additional power supply connection. In all embodiments, the first electrical connection can, for example, have a first resistance ^ ^ For example, the first resistor ^ ^ greater than or equal to 0.01^2, ie preferably ^ ^≥ 0.01^2. By choosing the resistor, the polarization voltage ^ ^,^ between the first electrode and the second electrode (assuming that an ionization current ^ ^^^ flows, see above). Preferably, the second electrical connection has a second resistance ^ ^ preferably the second resistor ^ ^ greater than or equal to the first resistance ^ ^ is, ie preferably ^ ^ ≥ ^ ^ . The relation ^ ^ ≥ ^ ^ is not a necessary condition because the resistance ^ ^ in the current path to be avoided is only a partial resistance. In practice, ^ ^ therefore also be smaller, e.g. ^ ^ ≥ 0.75 ⋅ ^ ^ . More generally, it is preferred if ^ ^ ≥ 0 ⋅ ^ ^is sufficient, where 0 ∈ A, A = {0.75; 0.8; 0.9; 1; 1.5; 2; 2.5}, ie0 can take on any value of the set A, with larger values ​​being preferred. The first connection and the second connection are preferably made of a conductive plastic. Conductive plastics can be incinerated; separation of metals or other electronic components from the filter insert is not necessary after the end of its service life. The costs for filter handling are reduced and filter handling is made easier. The manufacture of the filter insert is also simplified because the connections can be produced using the injection molding process. Description of the drawings The invention is described below without limiting the general inventive concept using exemplary embodiments with reference to the drawings.Figure 1 shows a schematic view of the structure of the filter unit. Figure 2 shows a schematic view of the structure of a second filter unit. Figure 3 shows a schematic view of the structure of a second filter unit. The filter unit 1 in Figure 1 preferably has a filter housing 10 which forms a fluid channel 13 with a preferred flow direction 3. The fluid channel 13 can, for example, be formed by at least one wall 14 and, corresponding to the preferred flow direction 3, preferably has at least one inlet opening 11 and at least one outlet opening 12. The filter unit preferably has a filter holder 18 for receiving a filter insert 100 in the fluid channel 13. Accordingly, during operation of the filter unit, the filter insert is flowed through in the preferred flow direction 3. The filter unit 1 also preferably has at least one spray electrode 15. The spray electrode 15, together with at least one counter electrode 110, preferably forms an electrostatic precipitator.The highly simplified Figure 1 shows several spray electrodes 15 arranged on a fluid-permeable support, the tips of which point toward the counter electrode 110. The number and orientation of the spray electrodes 15, as well as the arrangement on the support, are each preferred examples from which deviations may be made. The counter electrode 110 is preferably fluid-permeable; it can, for example, be designed as a grid electrode and / or have pores. Preferably, as shown in Fig.1 to Fig.3, the counter electrode 110 is the first electrode 110 of a preferably replaceable filter insert 100. The filter insert 100 also preferably has a dielectric filter medium 115 and / or a second electrode 120. Preferably, the first electrode 110 and the second electrode 120 are directly on the filter medium 115, iearranged on sides of the filter medium 115 facing away from each other. In this sense, the filter medium 115 is preferably located between the first electrode 110 and the second electrode 123. The first electrode 110 and the second electrode 123 are preferably fluid-permeable; for this purpose, they can have pores and / or be designed as a grid. The first electrode 110, the second electrode 120 and the filter medium 115 therefore preferably form a polarization filter, as shown. This can, for example, also have a lamination, sealing elements, a frame, or the like. As shown in Fig. 1, the filter insert 100 preferably has at least one first electrical connection 101 (e.g., a first plug contact) which is preferably connected at least to the first electrode 110. In addition, the filter insert 100 preferably has at least one second electrical connection 102 (e.g.,a second plug contact) which is preferably connected at least to the second electrode 120. Preferably, the spray electrode 15 is connected to a spray electrode output 28 of a power supply 20 via an electrically conductive spray electrode connection 25. A further output 29 of the power supply 20 is preferably connected to the first electrode via a first electrically conductive connection 21. The first electrically conductive connection 21 consequently includes the first electrical connection 101 and the corresponding counterpart 31 (first connection contact 31) on the filter housing 10. During operation, an ionization current ^ therefore flows. ^^^ from the power supply 20 via the spray electrode connection 25 to the spray electrode 15, from there to the first electrode 110 and then via the first connection to the further output 29. The first connection has a first resistance ^^ . This means that during operation a voltage drops at the first connection ^ ^^ = ^ ^^^ ⋅ ^ ^ and the resistance ^ ^ The second electrode 120 is preferably connected in parallel to the first electrode 110 by means of a second electrically conductive connection 22 to the further output 29 of the voltage supply 20. The second electrically conductive connection 22 consequently includes the second electrical connection 102 and the corresponding second counterpart 32 (second connection contact 32) on the filter housing 10. The potential of the further output 29 is thus applied to the second electrode 120. This further potential is shown as grounded here merely for illustrative purposes, but this is merely a preferred variant. Because during operation the voltage across the first resistor ^ ^^ drops, the voltage between the first electrode 110 and the second electrode 120 is ^ ^^ = ^ ^,^ = ^'^( Therefore, the dielectric filter medium 115 between the first electrode 110 and the second electrode 120 is polarized in the electric field between the first electrode 110 and the second electrode 120, and the filtering effect is improved accordingly. Therefore, only a power supply 20, preferably in the form of a constant current source, and a resistor ^ are required to operate the electrostatic precipitator and the polarization filter. ^ necessary, which drastically reduces manufacturing costs. Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 13 / 27 19.07.2024 Preferably, the second connection 22 has a second resistor ^ ^ .This is preferably high-impedance, e.g. ^ ^ ≥ 0.75 ⋅ ^ ^ (see above). Because no current flows through this resistor during trouble-free operation, a second resistor as high as possible worsens the ^the efficiency. However, if there is a breakdown through the filter medium 115 (ie a fault), then the second resistor ^ ^ as a current limiter and firstly prevents a breakdown and if this should occur, then the second resistor ^ ^ The larger the value of the second resistor ^ ^ the lower the risk of breakdown, the second connection 22 with the second resistor ^ ^ but must still allow a potential equalization between the further output 29 and the second electrode, ie the second resistor ^ ^must not be an insulator (for the difference between conductors and non-conductors, see Ashcroft Mermin, Solid State Physics, Saunders, Fort Worth, 1976, Chapter 12). Figure 2 shows a modification of the filter unit 1, which basically functions in the same way as the filter unit shown in Fig. 1. The description of Fig. 1 can also be applied to Fig. 2, except for the differences resulting from the following explanation. In simple terms, the filter unit according to Fig. 2 differs from that shown in Fig. 1 in that the first resistor ^ ^ and the second resistor ^ ^are arranged on the filter insert 100, i.e. between the first terminal 101 and the first electrode 110 or between the second terminal 102 and the second electrode 120. It is assumed herein that the other sections of the two connections 21, 22 have a resistance value that is negligible compared to the total resistance of the corresponding connection 21, 22. It is noted that in this embodiment, too, the resistance ^ ^ is optional, ie the total resistance of the second connection to ^ ^ can be neglected, but preferably ^ ^ ≥ 0.75 ⋅ ^ ^applies. Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 14 / 27 19.07.2024 Figure 2 therefore shows, among other things, a filter housing 10 having at least one power supply 20, at least one spray electrode 15 and at least one filter receptacle 18 for a filter insert 100, wherein the filter receptacle 18 is configured to receive a preferably replaceable filter insert 100. The filter housing 10 in Fig. 2 has a first connection contact 31 for the first electrode 110 and a second connection contact 32 for a second electrode 120. The power supply 20 preferably has a first spray electrode output 28 and a further output 29 and is preferably configured to generate an ionization current ^ ^^^ and a voltage ^ ^^^between the spray electrode outlet 28 and the further outlet 29. The spray electrode outlet 28 is therefore preferably connected to the spray electrode 15. The first connection contact 31 and the second connection contact 32 are preferably connected in parallel to one another to the further outlet 29 of the power supply 20. Figure 3 shows a further modification of the filter unit 1, which basically functions in the same way as the filter unit shown in Fig. 1 and Fig. 2. The descriptions of Figures 1 and 2 can also be read in Fig. 3, except for the differences resulting from the following explanation. In this modification, the further connection 29 is laid on the filter insert via a third electrical connection 23. The third electrical connection therefore replaces the part of the first and second connections 21, 22 which are required in the modifications according to Fig. 1 and Fig.2 run between the further connection 28 and the filter insert 100. Figure 3 therefore shows, among other things, a filter insert for the filter housing 10, wherein the filter insert 100 has a first electrode 110, a second electrode 120, and a third electrical connection 103, which is also referred to as a mating contact 103 (because it does not require a first or second connection). The mating contact 103 is preferably configured to electrically contact a connection contact 33 of the filter housing 10 when the filter insert 100 is inserted. The dielectric filter medium 115 is, as in the other variants, preferably arranged between the first electrode 110 and the second electrode 120.The first electrode 110 is preferably electrically connected to the mating contact 103 via the first electrically conductive connection 21, and the second electrode 120 is electrically connected to the mating contact 103 via the second electrically conductive connection 22, i.e., the first and second electrically conductive connections 21, 22 are connected in parallel. The optional connection point 29' is therefore at the same electrical potential as the further output 29 of the power supply 20. The optional resistors ^. ^ , ^ ^ can be part of the first or second connection 21, 22.

[0002] Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 16 / 27 19.07.2024 List of reference symbols 1 Filter unit (optional) 3 Preferred flow direction (optional) 10 Filter housing (optional) 11 Inlet opening (optional) 12 Outlet opening (optional) 13 Fluid channel (optional) 14 Wall (optional) 15 Spray electrode (optional) 18 Filter holder (optional) 20 Power supply (optional) 21 First connection (optional) 22 Second connection (optional) 25 Spray electrode connection (optional) 28 Spray electrode outlet (optional) 29 Additional outlet (optional) 31 First connection contact (optional) 32 Second connection contact (optional) 33 Connection contact (optional) 100 Polarization filter insert / filter insert (optional) 101 First connection (optional) 102 Second connection (optional) 103 Third connection / counter contact (optional) 110 first electrode (optional) 115 filter element / filter medium (optional) 120 second electrode (optional) ^ ^first resistance (optional) Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 17 / 27 19.07.2024 ^ ^ second resistor (optional) ^3third resistor (optional)

Claims

Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 18 / 27 19.07.2024 Patent claims 1. Filter unit (1) with at least one power supply (20), at least one spray electrode (15), at least one first electrode (110), at least one second electrode (120) and at least one filter medium (115), wherein - the filter medium is arranged between the first electrode (110) and the second electrode (120), - the first electrode (110) is arranged between the spray electrode (15) and the second electrode (120), - the power supply (20) has a spray electrode output (28) and a further output (29), - the power supply (20) is configured to generate an ionization current ^ ^^^ to give off, as well as a voltage ^ ^^^between the spray electrode output (28) and the further output (29), - the spray electrode output (28) is connected to the spray electrode (15), characterized in that the first electrode (110) and the second electrode (120) are connected in parallel to one another to the further output (29) of the power supply (20).

2. Filter unit (1) according to claim 1, characterized in that the first electrode (110) is connected via a first resistor ^ ^ is connected to the further output (29) and the second electrode (120) is connected in parallel to the first resistor ^ ^ is connected to the further output (29). Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 19 / 27 19.07.2024 3. Filter housing (10) comprising at least one power supply (20), at least one discharge electrode (15) and at least one filter receptacle (18) for a filter insert (100), wherein: - the filter receptacle (18) is configured to receive a filter insert (100) with a filter medium (115), wherein the filter medium (115) is arranged between a first electrode (110) and a second electrode (120), - the filter housing (10) comprises a first connection contact (312) for the first electrode (110), and the filter housing (10) comprises a second connection contact (32) for a second electrode (120), - the power supply (20) comprises a first discharge electrode output (28) and a further output (29), - the power supply (20) is configured to have an ionization current ^ ^^^ and a voltage ^ ^^^between the spray electrode output (28) and the further output (29), and - the spray electrode output (28) is connected to the spray electrode (15), characterized in that the first connection contact (31) and the second connection contact (32) are connected in parallel to one another to the further output (29) of the power supply (20).

4. Filter housing (10) according to claim 3, characterized in that the first connection contact (31) is connected via a first resistor ^ ^ is connected to the further output (29) and the second connection contact (32) is connected in parallel to the first resistor ^ ^ is connected to the further output (29). Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 20 / 27 19.07.2024 5. Filter unit (1) or filter housing (10) according to one of claims 1 to 4, characterized in that the power supply (20) is a constant current source.

6. Filter unit (1) or filter housing (10) according to claims 2 and 5 or 4 and 5, characterized in that for the voltage drop ^ ^^ = ^ ^^^ ⋅ at the first resistance applies: ^ ^^ ≥ ^ ^ ^ ^ ^^ with ^ ^ ^ ^ ^^ / ^ ∈ {100, 300, 500, 700, 900, 1000, 1200, 1500}.

7. Filter unit (1) or filter housing (10) according to claims 2 and 5 or 4 and 5 or 6, characterized in that the voltage drop ^ ^^ at the first resistance between 50% and 99% of the breakdown voltage ^ ^ ) ^ of the filter medium (115), ie0.5 ⋅ ^ ^ ) ^ ≤ ^ ^^ ≤ 0.99 ⋅ ^^ ) ^ .

8. Filter unit (1) or filter housing (10) according to one of the preceding claims, characterized in that the second electrode (120) is connected via a second resistor ^ ^ is connected to the further output (29) and the first electrode (110) is connected in parallel to the second resistor ^ ^ is connected to the further output (29).

9. Filter unit (1) or filter housing (10) according to claim 8, characterized in that for the value of the second resistor ^ ^ applies: ^ ^ ≥ α ⋅ ^ ^ , where 0 ∈ {0.75; 0.8; 0.9; 1; 1.5; 2; 2.5}.

10. Filter housing (10) according to one of claims 3 to 9, characterized in that: - a filter insert (100) is arranged in the filter receptacle (18), - the filter insert (100) has at least one filter medium (115), - the filter medium (115) is arranged between a first and a second electrode, Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 21 / 27 19.07.2024 - the first electrode (110) is connected to the further output (29) via the first connection contact (31), - the second electrode (120) is connected to the further output (29) via the first connection contact (31) and / or the second connection contact (32), and - the first electrode (110) is arranged between the spray electrode (15) and the filter medium (115) and / or between the spray electrode (15) and the second electrode.

11. Filter insert (100) for a filter housing (10), in particular for a filter housing (10) according to one of the preceding filter housing claims, wherein - the filter insert (100) has a first electrode (110), a second electrode (120), and an electrical counter-contact (101, 102, 103), - the counter-contact (101, 102, 103) is configured to detachably form a connection contact (31, 32,33) of a filter housing (10), - a dielectric filter medium (115) is arranged between the first electrode (110) and the second electrode (110), and - the first electrode (110) is electrically connected to the counter contact (101, 103) via a first electrically conductive connection (21), characterized in that the second electrode (120) is electrically connected to the counter contact (102, 103) via a second electrically conductive connection (22), and that the first electrically conductive connection (21) and the second electrically conductive connection (22) are connected in parallel to one another. Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 22 / 27 19.07.2024 12. Filter insert (100) according to claim 11, characterized in that the first electrical connection has a first resistance ^ ^ and that the first resistance ^ ^ greater than or equal to 0.01^Ω, ie ^ ^≥ 0.01^Ω.

13. Filter insert (100) according to claim 11 or 12, characterized in that the second electrical connection has a second resistance ^ ^ and that the second resistor ^ ^ is greater than or equal to 0.1^Ω, ie ^ ^ ≥ 0.1^Ω.

14. Filter insert (100) according to claim 12 and 13, characterized in that ^ ^ ≥ 0 ⋅ ^ ^, where 0 ∈ {0.75; 0.8; 0.9; 1; 1.5; 2; 2.5}.

15. Filter insert (100) according to one of claims 11 to 14, characterized in that the first connection and the second connection consist of a conductive plastic.

16. Method for applying a polarization voltage between a first electrode (110) of a polarization filter (100) and a second electrode (120) of the polarization filter (100), comprising the steps of: a. Generating a voltage drop in a first connection (21) between the first electrode (110) and a terminal (29, 29') by conducting an ionization current ^ ^^^ from an ionization voltage output (29) of the power supply via a spray electrode (15) and the first electrode (110) to the terminal (29), wherein one terminal (29, 29') is connected to another terminal (29) of the power supply or the other terminal (29) is Lohr, Jöstingmeier & Partner HEN 2023 / 01 WO Page 23 / 27 19.07.2024 b. Producing a second connection (22), wherein the second connection (22) electrically connects a second electrode (120) of the polarization filter (100) to the first terminal (29, 29'), whereby the level of the voltage drop in the first connection (21) is the polarization voltage.

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