FILTER HAVING A COIL ARRANGEMENT AND FILTER ASSEMBLY HAVING SUCH A FILTER

A filter for filtering an air flow, including a filter element with a bellows made of a pleated filter medium, wherein a coil arrangement is integrated into the filter element. A surface of the filter element is provided with the coil arrangement for inducing an electrical voltage. The surface having the coil arrangement is a surface of the bellows on an untreated gas side.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit to German Patent Application No. DE 10 2023 101 829.9, filed on Jan. 25, 2023, which is hereby incorporated by reference herein.

FIELD

The present invention relates to a filter and to a filter assembly having such a filter.

BACKGROUND

A very wide variety of filters which are used in air filtration are known from the prior art. Filters having pleated filter media are used in the air filtration for vehicle cabins. The filter media can have various layers here, e.g. electrically conductive layers. A layer having an electrostatic layer, which increases the degree of separation of the filter, can also be provided.

WO 2010/049 052 A1 discloses a filter element which is configured as what is referred to as a combination filter. Such a filter element filters particles and adsorbs gases. Filter elements of this type can be used to substantially keep passenger compartments free from harmful substances.

There is the requirement to bring about a particularly high filtration capacity and to admit only very well cleaned air into the passenger compartment. This requirement is met only with difficulty with well-known filter media. Particularly the decrease in the filtration capacity and in particular in the degree of separation causes problems over time.

EP 1 913 990 A1 describes a filter cartridge which has a coil arrangement. By means of the coil arrangement, the filter cartridge can be supplied with electrical energy using electromagnetic induction. For this purpose, a further coil arrangement is provided in a housing of the filter cartridge. The electrical energy can be stored in the filter cartridge and used, for example, for a sensor located there.

SUMMARY

In an embodiment, the present disclosure provides a filter for filtering an air flow, comprising a filter element with a bellows made of a pleated filter medium, wherein a coil arrangement is integrated into the filter element.

DETAILED DESCRIPTION

In an embodiment, the present invention provides a filter and a filter assembly having a good degree of particle separation over a relatively long period of use.

According to an embodiment of the invention, it has been recognized as being advantageous to provide the filter element with a coil arrangement such that a voltage can be induced in the filter element.

The filter according to an embodiment of the invention serves for filtering a fluid flow, in particular an air flow, wherein the filter has a filter element with a bellows made of a pleated filter medium. The filter element can furthermore also have edge strips—alternatively referred to as edge tapes—which delimit the bellows.

According to an embodiment of the invention, a coil arrangement is integrated into the filter element, for inducing an electrical voltage. This permits what is referred to as inductive energy transfer or inductive coupling. The coil arrangement may also be referred to as a secondary coil or receiver coil. The voltage induced in the coil arrangement can be used to increase the electrostatic charging of the filter element and thus to increase the degree of particle separation.

Since the coil arrangement is located integrated directly in or on the filter element, particularly simple manufacturing of the filter is possible. A complicated attachment of a coil arrangement is avoided.

The coil arrangement having its conductive elements can have a very wide variety of geometrical configurations as long as it can carry out the function of an electric coil. Lattice-like or serpentine-shaped or meandering coil geometries are thus conceivable.

In an advantageous embodiment, the surface of the filter element is provided with the coil arrangement.

According to a first embodiment variant of the filter, the surface having the coil arrangement is the surface on the untreated gas side, i.e. that surface of the bellows which is placed upstream in the direction of flow of the fluid flow.

The coil arrangement can extend here over part of the surface of the bellows and can be attached to the surface.

According to a second embodiment variant of the filter, the filter element has at least one edge strip and the at least one edge strip is fastened to the bellows. In an advantageous manner, the surface having the coil arrangement is a surface of the edge strip, in particular an outer surface.

In an advantageous embodiment of the filter, the coil arrangement is formed by a print on the filter element. The print can be made with an electrically conductive dye or paste, either on the filter medium before the latter is pleated, or on the edge strip.

In a refinement of the filter, the coil arrangement is formed by a nonwoven layer of the filter medium or of the edge strip, which is provided with metallic fibers or with metallic particles.

In a development of the filter, the coil arrangement is formed by concentric lines on the filter element, i.e. the bellows or edge tape.

In an advantageous embodiment of the filter, the surface of the filter element is provided with conducting elements, which are electrically conductively connected to the coil arrangement or are part of the coil arrangement. The purpose of this is that the coil arrangement is able to receive voltage induced from a mating coil, and then distributes charge across the conducting elements on the surface of the bellows. The conducting elements form a conductive layer of the filter medium, said layer ideally lying on the incident flow side of the filter. The induction of additional charge thus enables the degree of particle separation to be particularly readily increased. Alternatively, an arrangement on the discharge flow side is also provided. This is advantageous in particular in the case of a progressive building up of the filter medium.

The filter medium can be formed from nonwoven material, multilayer nonwoven material, multilayer nonwoven material with microfiber, multilayer nonwoven material with an active carbon layer, multilayer nonwoven material with a functional finish against allergens and microbiological substances, or from multilayer nonwoven material with an active carbon layer and with a functional finish against allergens and microbiological substances.

The coil arrangement can be formed from metallic fibers or from fibers with metallic particles or from a paste with electrically conductive particles, e.g. graphenes or graphene oxides, or metal particles or other electrically conductive particles.

An embodiment of the invention also relates to a filter assembly comprising a filter as described above and a housing in which the filter is accommodated. The housing can also be configured as a frame, shaft or the like.

According to an embodiment of the invention, the housing is equipped with a coil arrangement for generating an electromagnetic field, wherein the coil arrangement may be referred to as a primary coil or transmission coil. The coil arrangement of the housing and the coil arrangement of the filter element are positioned relative to each other in such a way that generation of an induced voltage in the coil arrangement of the filter element is made possible. That is to say, there is no direct power-conducting contact between the coil arrangements, and the latter are spaced apart from one another, preferably by less than 2 cm. A particularly good inductive energy transmission is then made possible.

In a development of the filter arrangement, the induced voltage generated in the coil arrangement of the filter element is distributed by a line system having conducting elements on the surface of the bellows, so that an increased electrical charge is generated on the surface of the bellows, which increases the degree of particle separation. In particular, the particle separation rate according to DIN 71460-1 for NaCl particles is thus increased by at least 20% compared to the state without a coil arrangement. In a development, the degree of particle separation is increased by at least 30% by high voltage being produced.

An embodiment of the invention also relates to the use of a filter assembly as previously described as an interior air filter for the cabin of a motor vehicle.

The described embodiments of the invention and the described advantageous developments of the invention are also advantageous developments of the invention in combination with one another, if this is technically feasible.

With regard to further advantages and in a structural and functional respect of advantageous refinements of the invention, reference is made to the description of exemplary embodiments with reference to the attached figures.

Embodiments of the invention will be explained in more detail below with reference to attached figures. Mutually corresponding elements and components are provided with the same reference signs in the figures. For better clarity of the figures, an illustration true to scale has been omitted.

FIG.1illustrates a perspective view of a filter. The filter10serves for filtering an air flow L, wherein the filter10has a filter element3with a bellows1made of a pleated filter medium7, and the filter element3has two edge strips2, and the edge strips2are fastened to the bellows1.

The surface of the filter element3is provided with a coil arrangement4for inducing an electrical voltage. The coil arrangement4can be attached to the surface of the bellows1on the untreated gas side101(position5) or to a surface of the edge strip2(position6).

FIG.2aillustrates a top view of a filter element. In this exemplary embodiment, the coil arrangement4is formed by concentric lines on the bellows1of the filter element3. In the variant ofFIG.2c, it is formed by a lattice-like geometry.

FIG.2billustrates a view of an edge strip. In this exemplary embodiment, the coil arrangement4is formed by concentric lines on an edge tape2of the filter element3. In the variant ofFIG.2d, it is formed by a reduced meandering shape.

FIG.3illustrates a schematic view of a filter assembly. The filter assembly1000comprises a filter10and a housing20in which the filter100is accommodated. The housing20is equipped with a coil arrangement21for generating an electromagnetic field, and the coil arrangement21of the housing20and the coil arrangement4of the filter element3are positioned relative to each other in such a way that generation of an induced voltage in the coil arrangement4of the filter element is made possible.

FIG.4aillustrates a cross section through a filter medium having a plurality of layers. The coil arrangement4is formed by a print on the filter medium7.

The uppermost layer of the filter medium7and therefore the surface of the filter medium7is provided with conducting elements which are electrically conductively connected to the coil arrangement4.

As a result, the induction voltage produced in the coil arrangement4of the filter element can be distributed by a line system having conducting elements on the surface of the bellows1, so that an increased electrical charge is generated on the surface of the bellows1, which increases the degree of particle separation.

The filter medium7illustrated is formed from a multilayer nonwoven material with a central active carbon layer.

In the variant ofFIG.4b, the coil arrangement4is attached to the surface of the filter medium7on the pure gas side. The filter medium7can have a progressive buildup here. This means that the layers of the filter medium become ever finer—in the throughflow direction of the air flow L.

In the variant ofFIG.4c, the coil arrangement4is attached to the surface of a layer8of the filter medium7, the layer8being an interior layer of the filter medium7.

In an alternative refinement of a filter assembly, the charging of the surface of the filter element could also be generated by a high voltage being applied to conducting elements of the filter element. The transmission can be undertaken by wired connection, e.g. copper cables. A high voltage is understood here as meaning an electrical voltage of greater than 5 kV, in particular of 10 kV with a low current strength of below 10 mA.