Cabin air filtration devices and components

Abstract

A gas purification device comprises a filter cartridge having a filter medium (220) and at least a first filter terminal (232), a duct comprising a filter support, wherein the filter support removably supports the filter cartridge in a duct volume between a gas inlet and a gas outlet, and a gas ionizer (300), wherein the gas ionizer (300) provides enhanced intrinsic safety against malfunction, ozone release and electric shock of maintenance personnel in case of insertion of the filter cartridge into the filter support, if the first duct terminal (131) is in contact with the first filter terminal and a first ionization terminal (331) is electrically connected with the first duct terminal via the first filter terminal. In case of removal of the filter cartridge, the electrical connection between the gas ionizer (300) and the duct terminal is interrupted.

Description

TECHNICAL FIELD

[0001] The present invention relates to a passenger compartment air filtration system, or more generally, to a gas purification device comprising a filter cartridge having a filter medium and at least a first filter terminal for providing electrical contact with a first duct terminal of a duct. The duct can further comprise a duct wall enclosing a duct volume having an upstream gas inlet and a downstream gas outlet. The filter cartridge can be removably supported in the duct volume between the gas inlet and the gas outlet by a filter support. The gas purification device can further comprise a gas ionizer for ionizing at least a portion of the gas flow through the duct. The gas ionizer can comprise at least a first ionization electrode and a second ionization electrode, a first ionization terminal and a second ionization terminal. The first ionization terminal can be electrically connected to the first electrode and the second ionization terminal electrically connected to the second electrode. BACKGROUND

[0002] The passenger compartment air filtration system removes pollutants from ambient air and provides purified air to the interior of the passenger compartment of a vehicle. Essentially the same technology can be used in other fields, for example in building ventilation.

[0003] Generally, "filtration" refers to the removal of particulate matter from a gas flow by sieving the gas flow using a fibrous filter - a sieve. Purifying air based on sieving alone requires a balance between the size of the smallest particles that are blocked in the sieve and the pressure drop of the sieving element - the fibrous filter medium. The removal of particulate matter from a gas flow by filtration appears to be the result of many actions, including interception, diffusion, inertial impaction. It has been proposed to improve the removal of particles from a gas flow by means of an electret filter using electrostatic forces. However, the particle removal of these electret filters appears to weaken with increasing particle deposition on the fibers. To address this shortcoming, it has been proposed to exert an external electric field on the filter medium by positioning the filter medium as a dielectric between two air-permeable electrodes. Using this technology, even uncharged sub-micron particles can be effectively removed from a gas flow. This technology is known as active field polarized medium air purification, which is different from electrostatic precipitation filters and passive electrostatic filters (electret filters).

[0004] These active field polarized medium gas purifiers generally have a gas filter housing having a receptacle for a gas filter and a high voltage (HV) power supply connected to the electrodes of the gas filter. Once the service life of the gas filter is reached, it is removed from the housing and replaced by another gas filter. The housing therefore has at least two electrical contacts for removably contacting corresponding electrical contacts of the gas filter, thereby enabling the provision of an electrical connection of the gas filter to the HV power supply.

[0005] US 2007 / 0199450 Al proposes an air filter with two air-permeable ground electrodes and an air-permeable HV electrode between the two ground electrodes. Between each ground electrode and the HV electrode is a dielectric filter medium. The HV field between the electrodes polarizes both the particles and the fibers of the dielectric medium.

[0006] While these active field polarizing medium air purifiers allow efficient removal of even sub-micron particles, air ionization enables disinfection of the air and removal of odors on a molecular scale. Air ionization requires about 5 kV - depending on the distance of the electrodes, and typically a current of 10 mA to 10 mA - depending on the size of the air ionizer. Corona discharge air purifiers are an example of air ionizers. Gas ionizers of industrial scale can accordingly have a larger current.

[0007] WO 2020 / 263171 Al proposes to use the electrically conductive filter medium of a filter cartridge as electrode for a gas ionizer. A plurality of isolated supports for the emission electrodes with a tip pointing in the upstream direction are attached to the upstream side of the filter element. The emission electrodes are supplied with about 7 kV to 10 kV while the filter medium is grounded. The voltage between the filter medium and the emission electrodes leads to a corona discharge which helps particle removal in the gas stream through the filter element. The power supply is directly attached to the filter cartridge and removed with the filter cartridge when the filter cartridge is replaced. The power supply can then be removed from the used filter cartridge and mechanically attached to the support structure of a new filter cartridge. Furthermore, the output terminals of the power supply are to be connected with the emission electrodes of the gas ionizer via cables. The ground electrode is embedded in the center of the filter medium and can be, for example, an activated carbon layer or a carbon fiber layer of the filter medium. The ground electrode layer is contacted by a needle which is passed through the layered filter medium. The needle is connected with the ground connector of the power supply by a wire.

[0008] US 2019 / 160475 Al proposes an electrostatic air filter with reduced ozone and nitrogen oxide emissions. The electrostatic air filter includes an air flow passage having an inlet with an ionizer including corona electrodes and accumulation electrodes. The corona electrodes are electrically connected to each other and the accumulation electrodes are electrically connected to each other while the accumulation electrodes are insulated from the corona electrodes such that a corona discharge occurs between the corona electrodes and the accumulation electrodes. The corona discharge ionizes contaminant particles present in air flowing through the passage. The contaminant particles are separated downstream using input electrodes and output electrodes. The air flows through both electrodes toward the passage outlet. The electric field strength in the space between the input electrodes and the output electrodes is opposite in direction to the electric field strength in the space between the ionizer and the input electrodes.

[0009] KR2020 / 0057523 addresses the problem of sparking in an electric filter by proposing an ionization unit comprising a discharge electrode applying an anode voltage and a counter electrode plate applying a cathode voltage. Dust is ionized by these electrodes and collected by a dust collecting unit having an anode plate and a cathode plate, the anode plate being disposed at a rear side of the ionization unit, the dust collecting unit being configured to collect dust ionized when passing through the ionization unit. The anode plate and the cathode plate are alternately stacked while being vertically spaced apart from each other. The electrode plates comprise a metal plate and an insulating layer for protecting the electrode plates from contact with moisture.

[0010] JPH0691199A relates to an electric osmosis dewatering method of sludge, wherein the sludge is heated before electric osmosis dewatering. SUMMARY

[0011] The problem to be solved by the present invention is to reduce waste, to facilitate recycling of used filters, and to improve the operational safety of a gas purification device having a gas ionizer.

[0012] The solution to the problem is described in the independent claims. The dependent claims relate to further improvements of the invention.

[0013] For example, the solution can be a cabin air purifier, or more generally, a gas purification device, and components thereof, either combined or separate. The gas purification device can comprise an optional filter cartridge. The filter cartridge can have a filter medium and at least a first filter terminal and / or a second filter terminal. Each of the filter terminals can be used to connect the filter cartridge to a power supply. In this context, connecting means providing an electrical connection between the filter terminals and respective connectors of the power supply in the usual way.

[0014] Preferably, the filter medium can comprise at least a capacitor having a first filter electrode and a second filter electrode. At least one of the filter electrodes can be electrically connected to the respective filter terminal. An electric medium can be located between the first filter electrode and the second filter electrode. For example, the first filter terminal can be electrically connected (short: connected) to the first filter electrode, and / or the second filter terminal can be connected to the second filter electrode. Via the first filter terminal and / or the second filter terminal, the filter electrodes can be connected to the power supply, but other ways of connecting the first electrode and / or the second electrode to an output port of the power supply can also be used.

[0015] In the usual way, the at least one filter medium is permeable to a fluid, e.g. a gas, in particular air, but impermeable to particles above a given particle size. Thus, the filter medium can be regarded as a sieve.

[0016] The gas purification device can further comprise a duct. The duct can be defined by and / or comprise a duct wall. The duct wall can enclose a duct volume having an upstream gas inlet and a downstream gas outlet. Thus, in a usual manner, a gas stream to be purified can enter the gas inlet, flow through the duct, and exit the duct via the gas outlet. Thus, the gas inlet can be considered as an upstream end, while the gas outlet can be considered as a downstream end of the duct.

[0017] The duct can further comprise a filter support, wherein the filter support is configured to removably support a filter cartridge in the duct volume between the gas inlet and the gas outlet in an operational position. In other words, the gas flowing from the gas inlet passes through the filter medium before exiting the duct via the gas outlet. For example, the filter support can be a tray configured to receive a filter cartridge and to hold the filter cartridge in position between the gas inlet and the gas outlet during normal operation of the gas purification device.

[0018] Removable means that the filter cartridge can be moved from an "inserted position", which can also be referred to as an operational position, to a removed position, which is a so-called "non-inserted" position. In other words, preferably, the filter cartridge is configured to be moved between an inserted position and a non-inserted position. In the non-inserted position, the filter cartridge can but need not be supported by the filter support.

[0019] Generally, it can be assumed that in the inserted position, the gas flowing through the duct passes through the filter medium of the filter cartridge, preferably the entire gas stream passes through the filter medium. However, in some applications, a bypass of the gas stream can be accepted and / or unavoidable and / or even possibly required. In other words, in the inserted position, preferably, the filter cartridge is configured to provide a first percentage of a given gas stream passing through the duct to pass through the filter element of the filter cartridge, while in the non-inserted position, the filter cartridge is configured to not filter or to filter only a reduced second portion of the gas stream passing through the duct. Thus, the second portion that is filtered corresponds to a percentage that is lower than the first percentage. For example, the lower percentage can designate a significantly lower percentage, which can be considered to be equal to or less than 50% of the first gas stream. In a preferred example, the filter cartridge is completely removed from the duct with the filter cartridge in its non-inserted position.

[0020] The duct can further comprise a first duct terminal and / or a second duct terminal. In case of an inserted filter cartridge into the filter support, the first duct terminal can be in contact with the first filter terminal and / or the second duct terminal can be in contact with the second filter terminal. Thus, a voltage can be provided to the filter cartridge via at least one of the filter terminals. For the avoidance of doubt, “inserted” describes a state in which the insertion of the filter cartridge into the filter support is completed. It can also be said that in case of an already inserted filter cartridge into the filter support, the first duct terminal can be in contact with the first filter terminal and / or the second duct terminal can be in contact with the second filter terminal. If the filter has been removed, i.e. no filter cartridge is inserted, the first duct terminal can not be in contact with the first filter terminal and / or the second duct terminal can not be in contact with the second filter terminal. Thus, in a state in which the filter cartridge is not inserted into the filter support, i.e. in a removed state, the first duct terminal is electrically disconnected from the first filter terminal and / or the second duct terminal is electrically disconnected from the second filter terminal.

[0021] The gas purification device can further comprise a gas ionizer. The gas ionizer can at least comprise a first ionization electrode and a second ionization electrode, a first ionization terminal and a second ionization terminal, wherein the first ionization terminal is preferably electrically connected to the first electrode and the second ionization terminal is preferably electrically connected to the second electrode. Thus, by applying a respective voltage to the first ionization terminal and / or the second ionization terminal, a corona discharge can be observed. Such a corona discharge occurs if the electric field in the vicinity of the ionization electrode exceeds the dielectric strength of a fluid, e.g. a gas, in the duct volume, preferably the fluid can be air. Depending on the design of the ionization electrode, typical voltages for air purification by corona discharge are in the range of a few kV (e.g. 2 kV to 12 kV, typically 3 kV to 7 kV).

[0022] A corona discharge in air produces ozone (O3). However, O3 is considered to cause irritation to mucous and respiratory tissues of passengers in the passenger cabin. Thus, preferably, the ionization electrode is located upstream of the filter cartridge, because by this ordering of the ionization electrode and the filter cartridge, at least a major part of the O3 is converted to O2 when passing through the filter medium. For example, if activated carbon and / or polymers and / or carbon fibers are included in the filter medium, the O3 concentration in the air stream is significantly reduced when passing through the filter cartridge.

[0023] Preferably, the gas ionizer is located upstream of the filter element. For example, the gas ionizer can also be supported in the duct. In another example, the gas ionizer can be located in or can define a separate conduit, preferably in fluid communication with an upstream facing side of the filter element. For the sake of simplicity only, in the present document it is assumed that such a separate conduit and an optional valve for controlling the gas flow are part of the duct.

[0024] The ducts can likewise mechanically support the gas ionizer. Alternatively, the gas ionizer can be supported by other components. For example, the gas ionizer can be supported by a bracket, which can extend, for example, via at least one hole of the duct, and which can itself be supported by a support structure, such as a base, a chassis, a floor, a ceiling, a wall, a door leaf, etc. The manner of attachment is not important for the operation of the gas purification device and can be adapted to the respective application or use position of the gas purification device, which is most suitable.

[0025] Preferably, the filter cartridge provides an electrical connection between the first duct terminal and the first ionization terminal and / or between the second duct terminal and the second ionization terminal, if the filter cartridge is inserted into the filter support. Thus, the gas ionizer is disconnected from the power supply, if the filter cartridge is removed. Obviously, at least two ports or connectors of the power supply can be connected to the first duct terminal and / or to the second duct terminal. In a preferred example, at least one, preferably both, power supply ports (terminals) are provided by one or more duct terminals, respectively.

[0026] The first electrical connection can be provided by a first filter conductor of the filter cartridge, which is in contact with the first duct terminal and the first ionization terminal. In this sense, the first ionization terminal can be in contact with the first duct terminal via the first filter terminal, if the filter cartridge is inserted. The expression "via the first filter terminal" shall not exclude additional conductive ways in the electrical circuit between the first filter terminal and the first ionization terminal. For example, the first ionization terminal can contact a contact surface of any conductive element, which is electrically connected with the first filter terminal. The conductive element, which is contacted by the first ionization terminal, can be part of the filter cartridge, and / or part of the duct, or part of any other element of the gas purification device, as long as the first filter terminal is connected in series between the first duct terminal and the first ionization terminal, and thus in series between the first duct terminal and the first ionization electrode.

[0027] The second electrical connection can be provided by a second filter conductor of the filter cartridge, which is in contact with the second duct terminal and the second ionization terminal. In this sense, the second ionization terminal can be in contact with the first duct terminal via the first filter terminal, if the filter cartridge is inserted. The expression "via the second filter terminal" shall not exclude additional conductive ways in the electrical circuit between the second filter terminal and the second ionization terminal. For example, the second ionization terminal can contact a second contact surface of a second conductor, which is electrically connected with the second filter terminal. The conductive element, which is contacted by the second ionization terminal, can be part of the filter cartridge, and / or part of the duct, or part of any other element of the gas purification device, as long as the second filter terminal is connected in series between the second duct terminal and the second ionization terminal, and thus in series between the second duct terminal and the second ionization electrode.

[0028] In both cases, removal of the filter cartridge interrupts the connection of one or more of the duct terminals to its respective ionization terminal. Since the filter is removed, the electrical connection between the gas ionizer and the power supply is interrupted, and thus the risk of accidental release of O3 via the duct gas outlet into, for example, the passenger compartment of a vehicle or an office or living room or any other space in which humans or animals can be present is reduced accordingly. For the purpose of illustration only, to ensure the interruption function of the electrical current through the ionizer, it is sufficient that one of the first ionization terminal and the second ionization terminal is electrically connected to the respective duct terminal via the respective filter terminal. The respective other ionization terminal can be directly connected to the respective port of the high-voltage power supply, where "directly" in this sentence means in any way that does not include the respective filter terminal.

[0029] In a preferred example, the first duct terminal is in contact with the first filter terminal. Furthermore, it is preferred that the first ionization terminal is electrically connected to the first duct terminal via the first filter terminal. It is particularly preferred that the first duct terminal is in contact with the first filter terminal, and the first ionization terminal is in contact with the first filter terminal. Similarly, it is preferred that the second duct terminal is in contact with the second filter terminal, and the second ionization terminal is electrically connected to the second duct terminal via the second filter terminal. Removal of the filter cartridge automatically disconnects at least one of the first ionization terminal and the second ionization terminal from the power supply.

[0030] It is particularly preferred that the first duct terminal is in contact with the first filter terminal at the same time as the first ionization terminal is in contact with the first filter terminal, i.e. only when the first ionization terminal is in contact with the first filter terminal; and / or that the second duct terminal is in contact with the second filter terminal at the same time as the second ionization terminal is in contact with the second filter terminal. In any of the three possible cases, the voltage drop over the filter cartridge is reduced. This contributes to a direct reduction in operating and installation costs, since the size of the high-voltage power supply connected to the first duct terminal and / or the second duct terminal for providing electrical power to the gas ionizer can be correspondingly smaller.

[0031] For example, a first surface portion of the first filter terminal can be in electrical contact with the first duct terminal, and a second surface portion of the first filter terminal can be in electrical contact with the first ionization terminal. Similarly, a first surface portion of the second filter terminal can be in electrical contact with the second duct terminal, and a second surface portion of the second filter terminal can be in electrical contact with the second ionization terminal.

[0032] In any of the above examples, removal of the filter cartridge from the filter support provides a situation in which the first duct terminal is not in contact with the first filter terminal, and thus the first ionization terminal is at least electrically disconnected from the first duct terminal; and / or in which the second duct terminal is not in contact with the second filter terminal, and thus the second ionization terminal is at least electrically disconnected from the second duct terminal.

[0033] As mentioned above, it is preferred that the filter element further comprises a first polarization electrode, a second polarization electrode and a second filter terminal, wherein the first filter terminal is electrically connected with the first polarization electrode and the second filter terminal is electrically connected with the second polarization electrode. If the filter cartridge is inserted into the filter support, the second filter terminal is preferably in contact with the second duct terminal.

[0034] The second filter terminal and the second duct terminal can be omitted, for example, by providing a direct connection of the second polarization electrode with a respective port of the power supply, for example a ground terminal.

[0035] In a preferred example, the first filter terminal can be electrically connected to the branching point via a first resistor. Further, the second filter terminal can be electrically connected to the same branching point via a second resistor. The first polarization electrode can likewise be electrically connected to the branching point and the second polarization electrode can be electrically connected to the second filter terminal. This allows to adjust the voltage over the polarization electrodes by adjusting the ratio of the first resistor and the second resistor, thereby adapting it to the size and material of the filter medium between the filter electrodes. Thus, the polarization voltage can be adjusted according to the specific filter medium without the need to adjust the voltage provided by the power supply via at least the first duct terminal. This allows to adjust, for example, the filter medium according to different environmental conditions. For example, in humid climatic conditions, it can be desirable to use a filter different from a dry dust climate. This change in filter layout can require a change in polarization voltage which can be obtained by simply adjusting the first resistor and the second resistor which can be comprised in or by the filter cartridge. Further, a single high voltage power supply providing a single voltage can be used to power the gas ionizer as well as the gas polarizer.

[0036] For example, the first filter terminal and / or the second filter terminal can be made of, consist of, or comprise an electrically conductive polymer and / or an electrically conductive ceramic and / or an electrically conductive compound. The resistors and connections between the first filter terminal and the first polarization electrode and / or between the second filter terminal and the second polarization electrode can be made of the same material. These materials are not considered electronic waste and can thus be recycled or stored like normal garbage. If the terminals, resistors, etc. are typical electronic components, for example mounted on a printed circuit board, more resources are required and recycling is more difficult and costly.

[0037] As will have become apparent, it is preferred that the first filter terminal and / or the first resistor and / or the second filter terminal and / or the second resistor and / or the branching point are integral. These components can be made as a single piece which can be attached to the support structure of the filter cartridge. For example, the single piece can be attached to a side wall of the filter cartridge. For example, the optional side wall of the filter cartridge can define at least one narrow side of the filter cartridge and can be configured to close the gap between the duct wall and the filter cartridge.

[0038] The first and / or second filter terminal can have at least a first and / or second injection opening. The first injection opening can be in contact with the first duct terminal and / or the second injection opening can be in contact with the second duct terminal. This allows to reduce the contact resistance between the terminals in contact with each other, since the core of the electrically conductive polymer and / or electrically conductive ceramic and / or electrically conductive compound typically exhibits a reduced electrical resistivity compared to the electrical resistivity in the outer region, i.e. near the "normal" housing surface. At the injection opening position, the core reaches the housing surface and thus is accessible, i.e. in this region the contact resistivity is reduced.

[0039] Additionally or alternatively, the first duct terminal and / or the first ionization terminal is a blade inserted into the first filter terminal, respectively, and / or the second duct terminal and / or the second ionization terminal is a blade inserted into the second filter terminal, respectively. Thus, the blade can cut through the outer layer of the first and / or second filter terminal, thereby contacting the core portion of the terminal. This contact is particularly safe and reliable and provides a particularly low contact resistance.

[0040] In a preferred example, at least one of the first filter terminal, the second filter terminal, the first duct terminal and the second duct terminal is / are an electrically conductive pin and / or comprises an electrically conductive pin, wherein the pin is contacted by the respective terminal of the respective other entity. The electrically conductive pin can be accommodated by a first or second recess of the filter terminal or duct, respectively, and optionally, the recess can be delimited by a non-conductive recess wall. The respective terminal of the other entity can contact the pin inside the recess. To make it more vivid, if the pin is the first filter terminal, this pin can be referred to as first filter pin. In this case, the recess can be formed by the duct, e.g. by the duct wall, and / or the recess can be part of the filter support. Thus, the first filter terminal can be engaged into the recess at least together with a distal portion of the first filter pin, and upon engagement, the first filter pin can be in contact with the first duct terminal. Thus, in case of filter core removal, e.g. during maintenance, the recess wall can mechanically support the first filter pin and / or provide a shock protection for the duct terminal. Preferably, the first ionization terminal can be in contact with a proximal portion of the first filter pin. In case the electrically conductive pin is the second filter terminal, just replace first by second in the last five sentences. Proximal refers to the portion of the pin closer to the filter medium, i.e. the end of the pin which is in contact with the respective duct terminal.

[0041] As is apparent from the previous paragraph, the electrically conductive pin can be comprised by the filter cartridge and can be contacted by the first pipe terminal inside the recess. In this case, it is preferred that the distance between the first pipe terminal and the first ionization terminal, and / or the distance between the first pipe terminal and the edge of the recess wall facing the filter cartridge, is larger than the distance between the first ionization electrode and the second ionization electrode. Each of these measures increases the intrinsic safety: by the choice of these distances, a spark between the first ionization terminal and the first pipe terminal can be avoided in the case that the filter cartridge is not installed and the power supply is not switched off in the prescribed manner for any reason (e.g. a defective switch, a software error, etc.). Furthermore, the risk of an electric shock for a maintenance person replacing the filter cartridge is reduced.

[0042] The gas purification device can comprise a power supply, herein also referred to as a high voltage power supply. The high voltage power supply has a first power supply terminal and a second power supply terminal. The high voltage power supply can have a voltage supply housing. The voltage supply housing can be attached to the pipe and / or at least partially integrated in the pipe. For example, a part of the pipe wall can also be part of the power supply housing, and / or the power supply housing can be attached to the pipe wall. The first power supply terminal can be electrically connected to and / or identical to the first pipe terminal, and optionally, the second power supply terminal can be electrically connected to and / or identical to the second pipe terminal. For example, the first pipe terminal can be connected to a high voltage output terminal of the power supply (i.e. the first power supply terminal), and the second pipe terminal can be connected to a ground terminal of the power supply (i.e. the second power supply terminal), or vice versa, the first pipe terminal can be connected to a ground terminal of the power supply, and the second pipe terminal can be connected to a high voltage output terminal of the power supply. The power supply and / or the pipe can have additional terminals. None of these terminals necessarily has to be a ground terminal, but at least one of these terminals can be a ground terminal.

[0043] Another solution to the above problem is provided by a method for connecting (and / or disconnecting) a first ionization terminal of a gas ionizer with a first pipe terminal of a gas pipe of a gas purification device, wherein the first filter terminal is electrically connected (and / or disconnected) with the pipe terminal and simultaneously connected (and / or disconnected) with the first ionization terminal. Preferably, the connection and disconnection is obtained by contacting and releasing the previously provided contact, respectively.

[0044] For example, the method can be performed by assembling a gas purification device as described above and / or shown in the figures, by inserting the filter cartridge into the filter support, electrically connecting the first filter terminal to the first pipe terminal, and by removing the filter cartridge from the filter support, to disconnect the connection.

[0045] Just to avoid any confusion, let us recall that the term "terminal" generally designates a point, in fact a piece having a contact surface, at which a conductor from a component, device or network ends (see for example https: / / en.wikipedia.org / wiki / Terminal_(electronics) Alternatively, it can be said that the terminals are electrical contacts. Examples of terminals are male pin connectors and / or corresponding female sleeve connectors and / or simple contact pads.

[0046] In the present text, bringing two parts into contact means providing electrical contact between the two parts by bringing them into direct contact. The connection therein is an electrical connection, i.e. the two electrically conductive parts of the connection are in contact, either indirectly or directly. An indirect connection can for example be provided by means of an electrical conductor in contact with both parts. In the case of a direct connection, the two electrically conductive parts are in contact with each other.

[0047] In the present text, a conductor is an electrical conductor (e.g. a metal), which of course can have an electrical resistivity. A conductor is distinguished from an insulator in that an insulator has a band gap ΔE between the Fermi level E f and the conduction band, wherein the band gap is larger than K β T (ΔE » K β T), T being the operating temperature, and K β the Boltzmann constant. A semiconductor (ΔE « K β T) should be considered a conductor. In short, a conductor is electrically conductive during normal operation, whereas an insulator is electrically non-conductive.

[0048] In the present text, the terms electrically conductive polymer and / or electrically conductive ceramic not only include polymers and / or ceramics that are conductors or semiconductors, but also include composites based on a matrix of electrically non-conductive polymer and / or electrically non-conductive ceramic material, in which electrically conductive material, such as metal and / or carbon fibers and / or graphite, etc., is integrated. Thus, an electrically conductive composite can have an electrically non-conductive matrix in which electrically conductive fibers are embedded, so that the electrical conductivity of the composite can be attributed to, for example, electrically conductive fibers (which can also be electrically conductive filaments, particles, beads, etc.) that are randomly distributed in the matrix. Of course, electrically non-conductive fibers can likewise be embedded in an electrically conductive matrix. In both cases, the composite material is capable of conducting electrical current. BRIEF DESCRIPTION OF DRAWINGS

[0049] Without limiting the general inventive concept, examples of embodiments of the invention will be described below by way of example with reference to the accompanying drawings.

[0050] Figure 1 A perspective sectional view of a gas filter device is shown.

[0051] Figure 2 A gas filter cartridge and a gas ionizer of the gas filter device of Figure 1 are shown.

[0052] Figure 3 The gas filter cartridge and the gas ionizer of Figure 1 are shown with a power supply in a top view.

[0053] Figure 3 A shows Figure 3 detail C of

[0054] Figure 3 B shows Figure 3 detail D of

[0055] Figure 4 A cross-sectional view taken along Figure 3 plane A-A of detail D of B is shown.

[0056] Figure 5 A cross-sectional view taken along Figure 3 plane B-B of detail C of A is shown.

[0057] Figure 6 A simplified view of the filter medium and the connection of the filter electrode to the respective terminal is shown. DETAILED DESCRIPTION

[0058] Figure 1 An example gas purification device 1 is shown in a perspective cross-sectional view. The gas purification device 1 has a duct 100 with a duct wall 110. By way of example only, the duct wall 110 can comprise a front wall 111, a back wall 113 and two side walls 112. In Figure 1 , one of the two side walls 112 is removed for illustration purposes only. The duct wall 110 has an upstream facing end face 3 and a downstream facing end face 4. The inner edge of the upstream facing end face 3 delimits an intake opening and the inner edge of the downstream facing end face 4 delimits an outtake opening.

[0059] The duct 100 can comprise or form a filter support which can accommodate a filter cartridge 200. The filter cartridge 200 has a filter medium 220. Preferably, the filter medium 220 is part of a capacitor, even more preferably, the filter medium 220 forms a capacitor. For example, the filter medium 220 can comprise a first polarization electrode 221 and a second polarization electrode 222. Between the two polarization electrodes 221, 222 can be a dielectric 223 (see Figure 6 ). The first polarization electrode 221 can be a first filter layer 221 and the second polarization electrode 222 can be a second filter layer 222.

[0060] From Figure 2It can be seen that the filter cartridge 200 can comprise an electrical module 240. The electrical module 240 can be made of, or comprise, and be attached to the filter cartridge 200, electrically conductive polymer wires and / or electrically conductive ceramic wires and / or electrically conductive compounds. Preferably, the electrical module 240 is a one-piece item. The filter cartridge 200 can further comprise a first filter terminal 231 connected to the first filter layer 221 and a second filter terminal 232 connected to the second filter layer 222. As depicted, the electrical module 240 can comprise the first filter terminal 231 and the second filter terminal 232 and can further comprise conductors connecting the first filter terminal 231 with the first filter layer 221 and the second filter terminal 232 with the second filter layer 222. Preferably, the first filter terminal 231 is connected with the branching point BR via a first portion (first resistor R1) of the electrical module 240. Further, preferably, the branching point BR can be connected with the second filter terminal 232 via a second portion R2 of the electrical module 241. The branching point BR can further be connected with the first filter layer 221 via a third portion R3 of the electrical module, i.e. via a third resistor R3. Further, as shown (see also Figure 6 ), preferably, the second filter terminal 232 can be connected to the second filter layer 222 by a fourth portion R4 of the module 240.

[0061] Upstream of the filter cartridge 200 can be a gas ionizer 300 (see Figures 1 to 3 ). Preferably, the gas ionizer 300 is likewise supported by the duct 100, but of course the gas ionizer 300 can likewise be supported by and / or attached to other components. In a particularly preferred example, the gas ionizer 300 can be supported independently of the filter cartridge 200, but again it is noted that such independence is not a requirement, although it simplifies maintenance. In this context, independent support means that the gas ionizer 300 can remain in place if the filter cartridge 200 is removed, e.g. taken out of a support (tray).

[0062] The gas ionizer 300 can have one or more first ionization electrodes 321 (regardless of the number, simply referred to as: first ionization electrodes 321) and one or more second ionization electrodes 322 (regardless of the number, simply referred to as: second ionization electrodes 322). The first ionization electrodes 321 can be electrically connected with a first ionization terminal 331 via a conductor. Similarly, the second ionization electrodes 322 can be electrically connected with a second ionization terminal 332 via a conductor. As can be seen, i.e. in Figure 2In this context, the first ionization terminal 331 can preferably be in direct contact with the first filter terminal 231 and / or the second ionization terminal 332 can preferably be in direct contact with the second filter terminal 232. As can be seen from this example, at least one ionization terminal, preferably both ionization terminals 321, 322, can preferably be in contact, preferably directly, with the outer peripheral surface of the respective filter terminal 231, 232. As shown in the depicted example, it is preferred that at least one of the first filter terminal 231 and the second filter terminal 232, shown as both, is a first pin 231 having a longitudinal axis 2311 and a second pin 232 having a longitudinal axis 2322, which longitudinal axes 2311, 2322 extend parallel to the direction of movement when the filter cartridge 200 is inserted into or removed from the duct 200, respectively. In this example, the direction of movement is indicated by the double-headed arrow 9 (see Figure 1 ). Just to rephrase, the first filter terminal 231 can have the shape of the first pin 231 and the second filter terminal 232 can have the shape of the second pin 232.

[0063] As can best be seen from Figure 2 , the filter cartridge 200 can have a front filter medium support 211 and / or a rear filter medium support 213. Preferably, the electrical module 240 is at least partially attached to the front filter medium support 211 and / or the rear filter medium support 213. Preferably, the front filter medium support 211 and / or the rear filter medium support 213 are made of an insulating material, such as paperboard, wood, insulating plastic, etc.

[0064] Furthermore, the gas purification device 1 can comprise a power supply 400 (see Figure 1 and Figure 3 ). The power supply 400 can provide a high voltage (e.g. 5 kV, more generally 3 kV to 7 kV, even more generally 1 kV to 10 kV, depending on the distance of the ionization electrodes) to the pair of duct terminals 131, 132, which can be seen in Figure 1 , Figure 4 and Figure 5 . As will be explained in more detail below, the first ionization terminal 321 is preferably connected with and / or via the first filter terminal 212 to the first duct terminal 121 and thus to the power supply 400. Similarly, the second ionization terminal 322 can be connected with and / or via the second filter terminal 222 to the second duct terminal 122. Thus, if the filter cartridge 200 is removed from the duct, the gas ionizer 300 is disconnected from the power supply 400 and generation of O3 into the passenger cabin in case no filter cartridge is installed can be avoided.

[0065] In Figure 3 , a top view (i.e. the viewing direction is parallel to the plane of the drawing) of the filter cartridge 200, the gas ionizer 300 and the power supply 400 is shown.Figure 1 the gas flow direction 2 in the middle is parallel). For illustrative purposes, Figure 4 and Figure 5 the pipe wall is omitted in the middle. Figure 3 A and Figure 3 B show Figure 3 details C and D of the first filter terminal 231, wherein two cross sections, namely A-A and B-B, are indicated. The cross section A-A extends through the first filter terminal 231 and the cross section B-B extends through the second filter terminal 232. The respective cross-sectional views are shown in Figure 4 and Figure 5 .

[0066] It can be seen from Figure 2 and Figure 4 that the first pipe terminal 131 can be an electrically conductive protrusion located in a first recess 161 of the pipe 100 (see Figure 4 ). As shown in Figure 4 , the power supply housing can provide a portion of the pipe wall 110 or can be partially integral with at least a portion of the pipe wall 110. The first recess 161 is delimited by a recess wall, and the first pipe terminal 131 can protrude through the bottom of the recess wall. In a preferred example, the first pipe terminal 131 can comprise an electrically conductive elastic element, for example a spring, which is preferably compressed in the event of insertion of the first filter terminal 131 into its final position in the first recess 161, thereby ensuring reliable electrical contact between the first pipe terminal 131 and the first filter terminal 231. In the final position of the first filter terminal 231, as depicted, the first filter terminal 231 engages into the first recess 161, thereby coming into contact with the pipe terminal 131. It can be seen from Figure 4 that the first ionization terminal 331 can be pressed against the housing wall by a shoulder of the first filter terminal 231. Thereby, the contact between the first filter terminal 231 and the first ionization terminal 331 is particularly good. Additionally or alternatively, at least one of the first ionization terminal 331 and the first pipe terminal 131 can be a blade that cuts into the first filter terminal 231.

[0067] Figure 5A very similar arrangement of a second conduit terminal 132, a second filter terminal 232 and a second ionization terminal 332 is shown. The second conduit terminal 132 can be an electrically conductive protrusion located in a second recess 162 of the conduit 100. As shown, the power supply housing can provide a portion of the conduit wall, or can be partially integral with at least a portion of the conduit wall 110. The second recess 162 is bounded by a recess wall, and the second conduit terminal 132 can protrude through the bottom of the second recess wall. In a preferred example, the second conduit terminal 132 can comprise an electrically conductive resilient element, for example a spring, which is preferably compressed in the event of insertion of the second filter terminal 132 into its final position in the second recess 162, thereby ensuring reliable electrical contact between the second conduit terminal 132 and the second filter terminal 232. In the final position of the second filter terminal 232, as depicted, the second filter terminal 232 can be engaged into the second recess 162, thereby making contact with the second conduit terminal 132. From Figure 5 It can be seen that the second ionization terminal 332 can be pressed against the housing wall by a shoulder of the first filter terminal 232. Thereby, the contact between the second filter terminal 232 and the second ionization terminal 332 is particularly good. Additionally or alternatively, at least one of the second ionization terminal 332 and the second conduit terminal 132 can be a blade that cuts into the second filter terminal 232.

[0068] From Figure 2 And Figure 6 It can be seen that the filter medium 220 can comprise one or more layers of sheets 221, 222, 223, but this is only a preferred example. Other types and shapes of filter medium 220 can equally be used. Preferably, the filter medium 220 can comprise at least three layers: two polarized electrode layers 221, 222 and a dielectric layer 223 located between the electrode layers 221 and 222. Thus, each of the polarized electrode layers 221, 222 can be regarded as an electrode 221, 222 of a capacitor 220, wherein the dielectric layer 223 is a dielectric 223 between the two polarized electrodes 221, 222 of the capacitor. Figure 6 Thus, the filter medium 220 can be a capacitor, and / or comprise a capacitor, and / or form a capacitor.

[0069] List of reference signs

[0070] 1 gas purification device

[0071] 2 flow direction

[0072] 3 upstream-facing side / end surface 3

[0073] 4 downstream-facing side / end surface

[0074] 100 conduit / gas filter housing

[0075] 110 pipe wall / housing wall

[0076] 111 front side wall / front wall

[0077] 112 side wall

[0078] 113 rear side wall / rear wall

[0079] 131 first pipe terminal / first pipe protrusion (optional)

[0080] 132 second pipe terminal / second pipe protrusion (optional)

[0081] 161 first recess (optional)

[0082] 162 second recess (optional)

[0083] 200 filter cartridge

[0084] 220 filter medium / capacitor (optional)

[0085] 221 first polarized electrode / first conductive filter layer

[0086] 222 second polarized electrode / second conductive filter layer

[0087] 223 dielectric (optional)

[0088] 231 first filter terminal / first pin (optional)

[0089] 2311 first terminal axis

[0090] 232 second filter terminal / second pin (optional)

[0091] 2311 second terminal axis

[0092] 240 electrical module (optional)

[0093] 300 gas ionizer (optional)

[0094] 321 first ionization electrode (optional)

[0095] 322 second ionization electrode (optional)

[0096] 331 first ionization terminal (optional)

[0097] 332 second ionization terminal (optional)

[0098] 400 power supply / high voltage power supply

[0099] R1 resistance / resistor between branch point BR and first filter terminal 231

[0100] R2 resistance / resistor located between the branching point BR and the second filter terminal 232

[0101] R3 resistance / resistor located between the branching point BR and the first polarization electrode 221

[0102] R4 resistance / resistor located between the branching point BR and the second polarization electrode 222

[0103] BR branching point

Claims

1. A gas purification device (1) comprising: - a filter cartridge (200) having a filter medium (220) and at least a first filter terminal (231), - a duct (100) comprising a duct wall (110) enclosing a duct volume having an upstream gas inlet and a downstream gas outlet, a filter support removably supporting the filter cartridge (200) in the duct volume between the gas inlet and the gas outlet, and at least a first duct terminal (131), - a gas ionizer (300) comprising at least a first ionization electrode (321) and a second ionization electrode (322), a first ionization terminal (331) and a second ionization terminal (332), wherein the first ionization terminal (331) is electrically connected to the first ionization electrode (321) and the second ionization terminal (332) is electrically connected to the second ionization electrode (322), characterized in that (i) in a state where the filter cartridge (200) is inserted into the filter support, the first duct terminal (131) is in contact with the first filter terminal (231) and the first ionization terminal (331) is electrically connected with the first duct terminal (131) via the first filter terminal (231), and (ii) in a state where the filter cartridge (200) is not inserted into the filter support, the first duct terminal (131) is not in contact with the first filter terminal (231) and the first ionization terminal (331) is electrically disconnected from at least the first duct terminal (131).

2. The gas purification device (1) according to claim 1, characterized in that the filter cartridge (200) further comprises a first polarization electrode (221), a second polarization electrode (222) and a second filter terminal (232), wherein the first filter terminal (231) is electrically connected to the first polarization electrode (221) and the second filter terminal (232) is electrically connected to the second polarization electrode (222) and, in case the filter cartridge (200) is inserted into the filter support, the second filter terminal (232) is in contact with a second duct terminal (132).

3. The gas purification device (1) according to claim 2, characterized in that the first filter terminal (231) is electrically connected to a branching point (BR) via a first resistance (R1), the second filter terminal (232) is electrically connected to the branching point (BR) via a second resistance (R2), the first polarization electrode (221) is electrically connected to the branching point (BR) and the second polarization electrode (222) is electrically connected to the second filter terminal (232).

4. The gas purification device (1) according to claim 2, characterized in that the first filter terminal (231) and / or the second filter terminal (232) consists of or comprises an electrically conductive polymer and / or an electrically conductive ceramic.

5. The gas purification device (1) according to claim 2, characterized in that the first filter terminal (231) and / or the second filter terminal (232) consists of or comprises an electrically conductive compound.

6. The gas purification device (1) according to claim 3, characterized in that At least two of the first filter terminal (231) and the first resistance (R1) and the second filter terminal (232) and the second resistance (R2) and the branching point (BR) are integral.

7. The gas cleaning device (1) according to any of claims 1 to 6, characterized in that A first surface portion of the first filter terminal (231) is in electrical contact with the first pipe terminal (131) and a second surface portion of the first filter terminal (231) is in electrical contact with the first ionization terminal (331).

8. The gas cleaning device (1) according to any one of claims 2 to 6, characterized in that A first surface portion of the second filter terminal (232) is in electrical contact with the second pipe terminal (132) and a second surface portion of the second filter terminal (232) is in electrical contact with the second ionization terminal (332).

9. The gas purification device (1) according to any one of claims 2 to 6, characterized in that: - at least one of the first filter terminal (231), the second filter terminal (232), the first pipe terminal (131) and the second pipe terminal (132) is and / or comprises an electrically conductive first pin, wherein the first pin is contacted by a respective terminal of a respective other entity, - the electrically conductive first pin is respectively received by the first filter terminal (231) or a first recess (161) of the pipe (100), and - the first recess (161) is delimited by an electrically non-conductive recess wall, and - the respective terminal of the other entity contacts the first pin inside the first recess (161).

10. The gas purification device (1) according to claim 9, characterized in that the filter cartridge (200) comprises the first pin and the first pin contacts the first pipe terminal (131) inside the first recess (161), and - a distance between the first pipe terminal (131) and the first ionization terminal (331) is greater than a distance between the first ionization electrode (321) and the second ionization electrode (322), and / or - a distance between the first pipe terminal (131) and an edge of the recess wall facing the filter cartridge (200) is greater than a distance between the first ionization electrode (321) and the second ionization electrode (322).

11. The gas cleaning device (1) according to any one of claims 2 to 6, characterized in that The first filter terminal (231) has a first injection inlet and / or the second filter terminal (232) has a second injection inlet; and the first injection inlet is in contact with the first pipe terminal (131) and / or the second injection inlet is in contact with the second pipe terminal (132).

12. The gas cleaning device (1) according to any one of claims 2 to 6, characterized in that A high-voltage power supply having a first power supply terminal and a second power supply terminal is attached to the pipe (100), wherein the first power supply terminal is electrically connected to and / or identical with the first pipe terminal (131) and / or, the second power supply terminal is electrically connected to and / or identical with the second pipe terminal (132).

13. The gas cleaning device (1) according to any one of claims 2 to 6, characterized in that The first pipe terminal (131) and / or the first ionization terminal (331) are blades inserted into the first filter terminal (231) respectively, and / or the second pipe terminal (132) and / or the second ionization terminal (332) are blades inserted into the second filter terminal (232) respectively, thereby providing the first pipe terminal (131) and / or the first ionization terminal (331) with electrical contact with the core material of the first filter terminal (231) respectively, and / or providing the second pipe terminal (132) and / or the second ionization terminal (332) with electrical contact with the core material of the second filter terminal (232) respectively.

14. Method for assembling a gas purification device (1) according to any one of claims 1 to 13, characterized in that, The method comprises electrically connecting the first filter terminal (231) to the first pipe terminal (131) by inserting the filter cartridge (200) into the filter support; and the first filter terminal (231) is electrically connected to the first pipe terminal (131) and simultaneously electrically connected to the first ionization terminal (331).

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