Filter insert for a filter system

Abstract

The invention relates to a filter insert (10) for a filter system (100) which comprises an ionizer (102), comprising an electrically insulating filter material (14), at least one electrically conductive polarization element (16a, 16b) to which an electric voltage can be applied in order to polarize the filter material (14), and a current collector (20) which is designed to protect the filter material (14) from an overload produced by an electrical breakdown and from the damage resulting therefrom.

Description

[0001] Filter insert for a filter system

[0002] The invention relates to a filter insert for a filter system comprising an ionizer, with an electrically insulating filter material and at least one electrically conductive polarizing element to which an electrical voltage can be applied to polarize the filter material.

[0003] Furthermore, the invention relates to a filter system with a filter insert and an ionizer.

[0004] In filter systems with an ionizer and filter media polarization, electrical arcing from the ionizer into the filter medium can occur. Such arcing is favored, for example, by moisture, which cannot be completely avoided in these types of filter systems.

[0005] An electrical arc can cause high local temperatures, which can damage the filter medium. Damage to the filter medium carries the risk of a permanent short circuit between the polarization elements. This short circuit prevents a voltage difference from being established between the electrodes, resulting in a loss of polarization. Furthermore, the ionizer may malfunction.

[0006] The object underlying the invention is therefore to reduce the risk of electrical flashover during the operation of electrified filter systems. This object is achieved by a filter insert of the type mentioned above, wherein the filter insert according to the invention has a current collector designed to protect the filter material from an overcurrent caused by a voltage breakdown and the resulting damage.

[0007] The voltage breakdown can be caused by an electrostatic discharge. For example, if the voltage between the ionizer and a polarizing element facing the ionizer is higher than the breakdown voltage of the insulating air space between the ionizer and the polarizing element, an electrical breakdown occurs, which is also referred to as a voltage breakdown. Damage to the filter material can lead to a short circuit between two polarizing elements. The voltage breakdown can originate, for example, from the ionizer. The current collector acts as a lightning rod on the filter element, protecting it from damage caused by flashovers.

[0008] In an alternative embodiment, the current collector can also be part of another component of the filter system, for example, the current collector can be part of a housing of the filter system into which the filter insert is inserted.

[0009] The filter insert according to the invention is advantageously further developed in that the polarizing element is designed as a polarizing layer. The polarizing layer preferably runs parallel to the electrically insulating filter material and / or is in planar contact with the electrically insulating filter material. The filter material is preferably an electret material or comprises an electret material.

[0010] Furthermore, a filter insert according to the invention is preferred in which two electrically conductive polarizing elements, each designed as a polarizing layer, are separated from one another by the electrically insulating filter material. An electrical voltage can be applied to the polarizing layers to polarize the filter material. The electrically insulating filter material and the two electrically conductive polarizing layers preferably form a pleated layer composite. The layer composite can further comprise one or more additional layers with additional functions, for example, an activated carbon layer and / or an anti-allergenic layer and / or an antibacterial layer and / or a nanofiber layer.

[0011] In another preferred embodiment of the filter insert according to the invention, the current collector comprises a collector device designed to collect the overcurrent caused by a voltage breakdown. Collecting the overcurrent caused by the voltage breakdown enables the dissipation of electrical charges beyond the filter material. Damage, in particular carbonization, of the filter material due to excessive discharge power caused by an electrical flashover is thus effectively prevented.

[0012] The filter insert according to the invention is further advantageously developed in that the catching device projects beyond the polarizing element. In particular, the catching device projects beyond the polarizing element to the outside and / or toward the ionizer and / or on the upstream side of the filter insert. The catching device projecting beyond the polarizing element locally reduces the separation distance between the ionizer and the polarizing element, thereby intercepting the overcurrent before it is introduced into the polarizing element. The catching device thus defines a flashover point.

[0013] Furthermore, a filter insert according to the invention is advantageous in which the collecting device is formed from a cured electrically conductive adhesive. The collecting device can be a cured electrically conductive adhesive strip. In particular, a plastic material can be used as the electrically conductive adhesive, which has a specific electrical resistance of 10 at 20 °C. 6Q*m or less. The polarizing element can be electrically contacted via the cured electrically conductive adhesive. The cured electrically conductive adhesive is preferably applied to the polarizing element and serves to fix a contact segment of a conductor carrier. The electrically conductive adhesive locally reduces the electrode spacing so that arcing can be conducted, for example, directly into a contact tab of a conductor carrier. Alternatively, the arresting device can be an electrically conductive arresting tip, for example made of an electrically conductive plastic or metal.

[0014] A filter insert according to the invention is also preferred in which the current collector comprises an electrical discharge path, via which an overcurrent caused by a voltage breakdown can be discharged beyond the insulating filter material and / or the polarizing element. A high current flow through the filter material and / or the polarizing element, which could lead to damage, is thus effectively avoided. The electrical resistance of the discharge path is comparatively low relative to the filter material or at least a dielectric layer of the filter material. The current along the discharge path can be reduced by a braking resistor outside the filter insert.

[0015] In another preferred embodiment of the filter insert according to the invention, the discharge path is formed, at least in sections, by a voltage divider of the filter insert, which serves to set a polarization voltage. In the event of a flashover, the voltage divider serves as a discharge path beyond the filter material. The voltage divider can be carried by a conductor carrier, such as a carrier film or a carrier label, applied to the outside of the filter insert, for example, on the side lamination. The conductor carrier can comprise at least one contacting segment for electrically contacting the conductor carrier with the polarization element. The contacting segment can be formed by a contacting tab.The contacting segment rests on the polarizing element and thus projects beyond the surface of the polarizing element, whereby the distance between the contacting segment and the ionizer is smaller than the distance between the polarizing element contacted via the contacting segment and the ionizer.

[0016] The filter insert according to the invention is further advantageously further developed by a series resistor, which is designed to reduce the current flow through the filter material caused by a short circuit. The series resistor is preferably a high-ohm electrical resistor. The series resistor is preferably connected upstream of the polarization element. With the series resistor, the discharge power caused by an electrical flashover is significantly reduced. The short circuit can be a short circuit between the polarization elements. The series resistor and the reduced current flow reduce the short-circuit-induced heat input into the filter medium, thereby protecting the filter medium from heat-related damage, such as carbonization.

[0017] The object underlying the invention is further achieved by a filter system of the type mentioned above, wherein the filter insert of the filter system according to the invention is designed according to one of the embodiments described above. With regard to the advantages and modifications of the filter system according to the invention, reference is therefore first made to the advantages and modifications of the filter insert according to the invention.

[0018] Alternatively or in addition to the current collector, the ionizer can be limited in power by means of a series resistor to protect the filter material from an overcurrent caused by a voltage breakdown and the resulting damage.

[0019] Alternatively or in addition to the current collector, the ionizer can comprise two plates to protect the filter material from an overcurrent caused by a voltage breakdown and the resulting damage. The plates can be spaced closer together than the ionizer electrodes. The ionizer electrodes can, for example, be spaced between 10 mm and 30 mm, for example 20 mm. The plates can, for example, be spaced between 2 mm and 10 mm, in particular between 6 mm and 8 mm. The ionizer operates, for example, with a voltage difference of between 0.2 kV / mm and 2 kV / mm between the electrodes. With comparatively pointed spray electrodes, a functioning and sufficiently high ionization of the air flowing through can occur at around 0.4 kV / mm, for example.A significant increase in humidity beyond the saturation limit, which can lead to droplet formation and / or fogging, can trigger a chain reaction in the ionized air, which can cause an electrical arc between the electrodes. The two plates prevent the arc from passing through or along the filter material, thus preventing localized carbonization and a resulting short circuit.

[0020] The filter system according to the invention is further advantageously developed in that the ionizer has an electrode unit with one or more discharge electrodes, wherein the electrode unit is preferably arranged adjacent to the filter insert. The electrode unit can be an electrode frame with one or more discharge electrodes. The polarizing element and the filter material preferably form a multi-layer composite. The composite layer has an inflow side and an outflow side. The electrode unit is preferably arranged on the inflow side of the composite layer.

[0021] Furthermore, a filter system according to the invention is advantageous in which the ionizer has a collecting electrode, wherein the collecting electrode is a component of the filter insert. One layer of the layer composite of the filter insert can serve as the collecting electrode of the filter insert. Preferably, the polarizing element of the filter insert serves as the collecting electrode of the ionizer. The polarizing element serving as the collecting electrode preferably has a lower potential or a zero potential to ground compared to another polarizing element. The polarizing element serving as the collecting electrode is preferably located on the side facing the ionizer or its electrode unit. As a result, no other layer of the layer composite will flash through when the flashover occurs.

[0022] A filter system according to the invention is also advantageous in which the ionizer has a collecting electrode, wherein the collecting electrode is arranged beyond the filter insert and / or is part of the electrode unit. This embodiment has the advantage that the collecting electrode can be replaced independently of the filter insert.

[0023] In a further preferred embodiment, the filter system according to the invention comprises an electrical supply module configured to supply the ionizer and the filter insert with current and / or an electrical voltage. The electrical supply module is preferably configured to provide a high voltage to the ionizer. The high voltage provided to the ionizer is preferably reduced to a lower voltage level by a voltage divider of the filter insert before the voltage is applied to the polarization elements for polarizing the filter material.

[0024] Preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying drawings.

[0025] Fig. 1 shows a filter insert according to the invention in a perspective view;

[0026] Fig. 2 is a detailed view of a current collector of a filter insert of a filter system according to the invention; and

[0027] Fig. 3 is a detailed view of a current collector of a filter insert of another filter system according to the invention.

[0028] Figure 1 shows a filter insert 10 of a filter system 100 that can be used in a motor vehicle. The filter system 100 serves, for example, as an interior air filter of the motor vehicle.

[0029] The filter insert 10 comprises a pleated layered composite 12 consisting of several layers. The layered composite 12 comprises an electrically insulating filter material 14 and two electrically conductive polarizing elements 16a, 16b. The polarizing elements 16a, 16b are designed as polarizing layers. A lower polarizing layer 16a is located below the filter material 14. An upper polarizing layer 16b is located above the filter material 14. Material strips 18a, 18b run along the lateral outer edges of the pleated layered composite 12. The material strips 18a, 18b form the side laminations of the filter insert 10 and are integrally bonded, for example, by adhesive bonding, to the pleated layered composite 12.

[0030] On the outer side of the material strip 18a is a conductor receiving surface 24, on which a conductor carrier 28 is arranged. The conductor carrier 28 is a carrier film or a carrier label. The conductor carrier 28 is glued to the conductor receiving surface 24.

[0031] The conductor carrier 28 runs along a total of three sides of the filter insert 10. The conductor carrier 28 runs along the top side of the filter insert 10, along the bottom side of the filter insert 10, and along a side surface of the filter insert 10. The conductor carrier 28 allows electrically conductive contact between the filter insert 10 and an electrical supply module of the filter system 100.

[0032] The filter insert 10 further comprises a current collector 20, which is designed to protect the filter material 14 arranged between the polarizing elements 16a, 16b from an overcurrent caused by a voltage breakdown and the resulting damage. If the filter insert 10 is used in a filter system 100 comprising an ionizer 102, a voltage breakdown can originate from the ionizer 102. For example, if a voltage is present between the ionizer 102 and the polarizing element 16b facing the ionizer 102 that is higher than the breakdown voltage of the insulating air space located between the ionizer 102 and the polarizing element 16b, an electrical breakdown, which is also referred to as a voltage breakdown, occurs.

[0033] The current arrester 20 essentially acts as a lightning rod on the filter insert 10. The current arrester 20 comprises an arresting device 26 and a discharge path 22. The arresting device 26 serves to arrest the overcurrent caused by a voltage breakdown. The overcurrent caused by the voltage breakdown can be discharged via the discharge path 22 beyond the insulating filter material and the polarization elements 16a, 16b.

[0034] The catching device 26 is a cured, electrically conductive adhesive strip. The catching device 26 projects beyond the upper polarizing element 16b in such a way that the separation distance between the ionizer 102 and the catching device 26 is locally reduced, thereby intercepting the excess current before it is introduced into the polarizing element 16b.

[0035] The cured electrically conductive adhesive of the arresting device 26 is applied to the polarization element 16b and serves to fix a contacting segment 30 of the conductor carrier 28. The contacting segment 30 is a contacting tab of the conductor carrier 28. The electrically conductive adhesive locally reduces the electrode spacing so that arcing is conducted directly into the contacting tab.

[0036] The discharge path 22 runs in a meandering shape in sections and is formed in some areas by a voltage divider of the filter insert 10, which serves to set a polarization voltage. In the event of a flashover, the voltage divider thus serves as the discharge path 22 beyond the filter material 14.

[0037] Figs. 2 and 3 show filter systems 100 with a filter insert 10 and an ionizer 102. Furthermore, the filter systems 100 comprise an electrical supply module (not shown) which serves to supply power to the ionizer 102 and the filter insert 10.

[0038] The ionizer 102 has an electrode unit 104 with a plurality of discharge electrodes, wherein the electrode unit 104 is arranged adjacent to the filter insert 10. The electrode unit 104 comprises an electrode frame on which the plurality of discharge electrodes are arranged.

[0039] The layered assembly 12, consisting of the filter material 14 and the polarizing elements 16a, 16b formed as polarizing layers, has an inflow side and an outflow side. The electrode unit 104 of the ionizer 102 is arranged on the inflow side of the layered assembly 12. In the embodiment shown in Fig. 2, the ionizer 102 has a collecting electrode 106, wherein the collecting electrode 106 is formed as a grid frame and is arranged beyond the filter insert 10. The collecting electrode 106 formed as a grid frame is a component of the electrode unit 104.

[0040] In the embodiment shown in Fig. 3, the ionizer 102 has a collecting electrode 32, wherein the collecting electrode 32 is a component of the filter insert 10. In this case, one layer of the layer composite 12 of the filter insert 10 serves as the collecting electrode 32. The polarizing element 16b, which serves as the collecting electrode 32 and is designed as a polarizing layer, is located on the side facing the electrode unit 104 of the ionizer 102. A separate collecting electrode outside the filter insert 10 is therefore not absolutely necessary in this case.

[0041] Reference symbol

[0042] 10 Filter insert 12 Layer composite 14 Filter material 16a, 16b Polarizing elements 18a, 18b Material strips 20 Current conductor 22 Discharge path 24 Conductor receiving surface 26 Air termination device

[0043] 28 Conductor carrier 30 Contact segment 32 Collecting electrode

[0044] 100 Filter system 102 Ionizer 104 Electrode unit 106 Collecting electrode

Claims

Claims 1. A filter insert (10) for a filter system (100) comprising an ionizer (102), comprising an electrically insulating filter material (14); and at least one electrically conductive polarizing element (16a, 16b) to which an electrical voltage can be applied to polarize the filter material (14); characterized by a current collector (20) configured to protect the filter material (14) from an overcurrent caused by a voltage breakdown and resulting damage.

2. Filter insert (10) according to claim 1, characterized in that the polarizing element (16a, 16b) is designed as a polarizing layer.

3. Filter insert (10) according to claim 1 or 2, characterized by two electrically conductive polarizing elements (16a, 16b) each designed as polarizing layers, which are separated from one another by the electrically insulating filter material (14).

4. Filter insert (10) according to one of the preceding claims, characterized in that the current collector (20) has a capturing device (26) which is designed to capture the overcurrent caused by a voltage breakdown.

5. Filter insert (10) according to claim 4, characterized in that the capture device (26) projects beyond the polarization element (16a, 16b), in particular outwards and / or in the direction of the ionizer (102) and / or on the upstream side of the filter insert.

6. Filter insert (10) according to claim 4 or 5, characterized in that the catching device (26) is formed from a cured electrically conductive adhesive.

7. Filter insert (10) according to one of the preceding claims, characterized in that the current collector (20) comprises an electrical discharge path (22) via which an overcurrent caused by a voltage breakdown can be discharged beyond the insulating filter material (14) and / or the polarizing element (16a, 16b).

8. Filter insert (10) according to claim 7, characterized in that the discharge path (22) is formed at least in sections by a voltage divider of the filter insert (10) serving to set a polarization voltage.

9. Filter insert (10) according to one of the preceding claims, characterized by a series resistor which is designed to reduce the current flow through the filter material (14) caused by a short circuit.

10. A filter system (100) comprising a filter insert (10) and an ionizer (102), characterized in that the filter insert (10) is designed according to one of the preceding claims.

11. Filter system (100) according to claim 10, characterized in that the ionizer (102) has an electrode unit (104) with one or more spray electrodes, wherein the electrode unit (104) is preferably arranged adjacent to the filter insert (10).

12. Filter system (100) according to claim 11, characterized in that the ionizer (102) has a collecting electrode (32), wherein the collecting electrode (32) is a component of the filter insert (10).

13. Filter system (100) according to claim 11, characterized in that the ionizer (102) has a collecting electrode (106), wherein the collecting electrode (106) is arranged beyond the filter insert (10) and / or is a component of the electrode unit (104).

14. Filter system (100) according to one of claims 10 to 13, characterized by an electrical supply module which is designed to energize the ionizer (102) and the filter insert (10) and / or to supply them with an electrical voltage.

Images