Filter material for filtering air in filter element and filter element having filter material

Abstract

The utility model relates to a filtering material for filtering air in a filtering element and the filtering element with the filtering material. The filter material (10) is equipped with a pre-filter layer (2) on the inflow side, an activated carbon layer (3) and a composite layer (1) which is designed as a fine filter layer having nanofibers. According to the utility model, the layers are connected with one another in a material locking manner. Since the pre-filter layer and the composite layer with nanofibers are combined in one filter material, a high dust storage capacity and a high mass coefficient are advantageously achieved at the same time.

Description

Technical Field

[0001] The utility model relates to a filter material for filtering air in a filter element, which comprises a pre-filter layer on the inflow side, an activated carbon layer and a composite layer, wherein the composite layer is constructed as a fine filter layer with nanofibers, and the utility model relates to a filter element with the filter material. Background Art

[0002] Known filters for filtering fluids, particularly air, are known from the prior art. For this reason, a filter element is usually inserted into a filter housing and is flowed through by air.

[0003] Different filter elements for filtering interior air are known from the prior art. For example, DE 10 2013 011 457 A1 describes an interior air filter element for driving cabins of agricultural and working machines.

[0004] The interior air filter element comprises an adsorption filter layer with activated carbon, a fine filter layer (in particular for separating aerosols) and a surrounding seal for separating the unfiltered side and the clean side when installed in the filter housing. Such multi-stage filters are also called multi-stage filters. By providing a pleated pre-filter layer, it is possible to protect the adsorption layer and the fine filter layer from excessive dust loads and to ensure their function for as long as possible. The disadvantage of this design is that the pre-filter layer requires additional structural space and the filter element is less compact. Utility Model Content

[0005] The object of the present invention is to provide a filter material which, compared with known filter materials, has a more stable filter efficiency over the use period, while the installation space requirement remains unchanged.

[0006] Technical Solutions

[0007] This object is achieved by the filter material described and claimed below.

[0008] The utility model relates to a filter material for filtering air in a filter element, comprising a pre-filter layer on the inflow side, an activated carbon layer and a composite layer, wherein the composite layer is constructed as a fine filter layer with nanofibers, the pre-filter layer, the activated carbon layer and the composite layer are connected to each other in a material-locked manner, and the composite layer comprises at least one covering layer, a nanofiber layer and a carrier layer.

[0009] According to the invention, it is found to be advantageous to combine the prefilter layer, the activated carbon layer as adsorption layer and the composite layer with nanofibers in one filter material.

[0010] The filter material according to the utility model is used for filtering air in a filter element. It comprises a pre-filter layer on the inflow side configured as a coarse dust filter layer, an activated carbon layer as an adsorption layer, and a composite layer as a mechanical filter medium. The composite layer is configured as a fine filter layer with nanofibers, which can be configured to have EPA (high efficiency particulate air) properties, for example.

[0011] According to the utility model, the composite layer has a nanofiber layer on a carrier layer, and the nanofiber layer is provided with a cover layer on the other side thereof. The layers are connected to each other in a material-locked manner. The carrier layer can be composed of coarse fibers, and the cover layer is composed of coarse fibers and / or microfibers.

[0012] According to the invention, the pre-filter layer, the activated carbon layer and the composite layer are also connected to each other in a material-locking manner. Thus, the layers are not connected in a form-locking manner by co-pleating, i.e., not by folding the layers together, but are connected in a material-locking manner. Such a material-locking connection is also referred to as "laminating one another".

[0013] The material-locking connection can be achieved by any type of lamination or coating, by means of bonding (polymer threads, powders, M-webs, reactive or thermal adhesives, such as thermoplastic hot melts, etc.), by hot pressing (calendering with / without fused fiber components) or by means of ultrasonic welding or calendering. The material-locking connection can be present over the entire surface or in spots on the layer surface. The advantage of the material-locking connection compared to the pleated connection of the individual layers is that a higher mechanical stability can be observed. Another advantage is the higher temperature stability: after heat storage in the filter material, a smaller increase in pressure loss can be observed compared to pleated filter materials of otherwise identical construction. The filter material can also be pleated well as a whole with its material-locking connected layers. Without a material-locking connection, usually at most two layers can be pleated together. The other layer must then be pleated separately, so that the filter element consists of two layers, namely the pleated layer and the pleated layer. However, such a filter element consisting of multiple layers therefore requires more structural space. Due to the material-locking connection of all layers, a filter medium having three or more layers can be provided which requires less installation space during subsequent pleating than a co-pleated filter medium.

[0014] Due to the combination of a pre-filter layer and a composite layer with nanofibers in one filter material, a high dust storage capacity and a high quality factor are simultaneously achieved. In terms of its thickness, this material offers good value: By using this filter material in the filter, good filter efficiency can be achieved without increasing pressure loss.

[0015] Compared to coarser fibers, nanofibers have the advantage that they have a larger surface area and can therefore achieve an increased filter performance and a longer filter service life. The higher barrier effect (interception effect) due to the smaller fiber diameter has a particularly positive effect here. In contrast to electrostatic separation, the effects attributed to mechanical separation are largely retained over the operating duration of the filter. In addition, filter media made of nanofibers have a lower pressure loss, which is accompanied by a lower energy requirement for the filter element.

[0016] The filter material according to the invention has an adsorption layer configured as an activated carbon layer, ie a layer having a certain proportion of activated carbon as an adsorbent. A filter element made of such a filter material is referred to as a combined filter.

[0017] In a particularly advantageous embodiment of the filter medium, the individual layers are connected by gluing using a polyolefin hot melt adhesive as a thermoplastic fusion adhesive. This has the following advantages:

[0018] - good adhesion properties on the substrate to be bonded,

[0019] ->High thermal stability of 105℃,

[0020] - stability with respect to oxidatively active degradation processes,

[0021] - High ageing resistance, and

[0022] - Less noticeable in terms of fogging and odor.

[0023] Polyolefin hot melt adhesives may also be used to bond the layers of the composite to each other.

[0024] In a further development of the invention, in the filter material, the pre-filter layer and / or the composite layer are electrostatically charged, for example, by corona or high-voltage technology, thereby further increasing the dust storage capacity.

[0025] In one possible design variant of the filter material, the activated carbon layer is provided with a permanently adhesive adhesive mesh. The permanently adhesive adhesive mesh can also be referred to as a mesh adhesive layer, which is introduced into the activated carbon layer. The adhesive layer can be produced using a polyolefin hot melt adhesive, which has filaments with a diameter of 5 to 20 micrometers that form the adhesive mesh. The permanently adhesive adhesive mesh can advantageously separate particularly coarse dust particles, thereby protecting the subsequent layers. Another function of the adhesive mesh is to attach and fix the adsorbed particles of the activated carbon layer.

[0026] In an extension of the filter material, the filter material has an additional coarse filter layer, which can also be called a coarse dust filter layer. The function of the coarse dust filter layer is, on the one hand, to provide a support structure for the activated carbon layer or to provide a support structure for the composite layer, and on the other hand to perform a filtering effect. The advantages of this filter material are therefore a higher stability and a higher dust storage capacity. The higher dust storage capacity helps to keep the increase in pressure loss of the filter element as low as possible during the use period, especially despite the presence of highly separating nanofibers. For this purpose, the coarse dust filter layer can be arranged upstream of the composite layer in terms of the flow direction.

[0027] In one possible embodiment of the filter material, the prefilter layer or the (possibly present) coarse filter layer forms the carrier and thus the support structure for the activated carbon layer. The activated carbon layer can also consist, in particular, of activated carbon particles bonded to one another.

[0028] In the case of an activated carbon layer with a large number of individual activated carbon particles, in the prior art, a bulk of these particles is usually applied to a support structure and fixed by bonding. If, as described here, a pre-filter layer or a (possibly present) coarse filter layer is used as a carrier, a filtering function can also be achieved by the pre-filter layer or the (possibly present) coarse filter layer, which further increases the filtering performance of the filter material.

[0029] Different variants of the filter material are conceivable, which differ in their structure. Here, the structure of the composite layer is uniform as follows when viewed in the flow direction: carrier layer, nanofiber layer, cover layer.

[0030] In a first variant, the filter material has a prefilter layer on the inflow side, a composite layer on the outflow side and an activated carbon layer located therebetween.

[0031] The following sequence of layers is thus visible in the flow direction:

[0032] 1) Pre-filtration layer

[0033] 2) Activated carbon layer

[0034] 3) Composite layer

[0035] In a second variant, the filter material comprises a prefilter layer on the inflow side, a coarse filter layer on the outflow side with an activated carbon layer applied thereto, and a composite layer located therebetween, wherein in particular the prefilter layer and the composite layer are designed as a unit which is materially connected to one another, for example by thermal welding. Thus, the following sequence of layers is visible in the throughflow direction:

[0036] 1) Pre-filtration layer

[0037] 2) Composite layer

[0038] 3) Activated carbon layer

[0039] 4) Coarse filter layer

[0040] In a third variant, the filter material comprises a pre-filter layer on the inlet side with an activated carbon layer applied thereon (the activated carbon layer being located downstream of the pre-filter layer), a composite layer on the outlet side and a coarse filter layer situated therebetween, wherein in particular the coarse filter layer and the composite layer are constructed as units which are materially connected to each other and are bonded to each other, for example, using a thermoplastic hot melt adhesive.

[0041] The following sequence of layers is thus visible in the flow direction:

[0042] 1) Pre-filtration layer

[0043] 2) Activated carbon layer

[0044] 3) Coarse filter layer

[0045] 4) Composite layer

[0046] In a fourth variant, a pre-filter layer on the inflow side, a coarse filter layer with an activated carbon layer applied upstream thereto, a further coarse filter layer and a composite layer on the outflow side are provided. In particular, the further coarse filter layer and the composite layer are constructed as a unit that is materially connected to each other, for example by thermal welding.

[0047] The following sequence of layers is thus visible in the flow direction:

[0048] 1) Pre-filtration layer

[0049] 2) Activated carbon layer

[0050] 3) Coarse filter layer

[0051] 4) Coarse filter layer

[0052] 5) Composite layer.

[0053] In the second, third and fourth variants, the unit that is materially connected to one another means that the pre-filter layer and the composite layer or the coarse filter layer and the composite layer have already been materially connected to one another by a previous process and are then materially connected to other layers in a further process step. The materially connected connection of the pre-filter layer or the coarse filter layer to the composite layer can be achieved thermally over the entire surface and / or by spot layer welding.

[0054] This allows the filter material to have a particularly high strength and good processability.

[0055] In one possible embodiment of the filter material, the filter material has a progressive structure, so that the porosity of the individual layers: pre-filter layer, activated carbon layer and composite layer from the inflow side (untreated gas side) to the outflow side (clean gas side) of the filter material gradually decreases from one layer to the next. The porosity here refers to the ratio of the cavity volume of the individual nonwoven layers to the total volume. Or in other words, the progressive structure means that the layers become finer and finer when viewed in the flow direction. This filter material provides particularly good dust filtration, and the pressure difference of the filter material is stable over time.

[0056] The utility model also relates to a filter element with the pleated filter material.

[0057] According to the filter element of the present invention having a filter material, the filter material is pleated, and the edge strip or the frame element is attached to the pleated filter material.

[0058] In one possible embodiment of the filter element, an edge band or a frame element can be attached to the pleated filter material, which edge band or frame element can stabilize the filter element and serve as a sealing element for a filter housing that accommodates the filter element.

[0059] The utility model also relates to the use of the filter element as an interior air filter for filtering and cleaning cabin supply air in a vehicle, in particular a passenger car, a commercial vehicle or a bus.

[0060] The invention and the advantageous refinements of the invention also constitute advantageous refinements of the invention in combination with one another, insofar as this is technically advantageous.

[0061] With regard to further advantages and structurally and functionally advantageous embodiments of the invention, reference is made to the description of the exemplary embodiments in the attached drawings.

[0062] Advantageously, the pre-filter layer and / or the composite layer are electrostatically charged.

[0063] Advantageously, the activated carbon layer is provided with a permanently adhesive adhesive network.

[0064] Advantageously, the filter material has an additional coarse filter layer.

[0065] Advantageously, the prefilter layer or the coarse filter layer forms the support for the activated carbon layer.

[0066] Advantageously, the activated carbon layer consists of activated carbon particles bonded to one another.

[0067] Advantageously, the filter material has the following construction: an inflow-side prefilter layer, an outflow-side composite layer, and an activated carbon layer located between the inflow-side prefilter layer and the outflow-side composite layer.

[0068] Advantageously, the filter material has the following construction: an inflow-side prefilter layer, an outflow-side coarse filter layer with an activated carbon layer applied thereto, and a composite layer between the inflow-side prefilter layer and the activated carbon layer.

[0069] Advantageously, the prefilter layer and the composite layer are designed as a unit which is materially connected to one another.

[0070] Advantageously, the filter material has the following construction: an inflow-side prefilter layer, an outflow-side composite layer, and at least one coarse filter layer and an activated carbon layer located between the inflow-side prefilter layer and the outflow-side composite layer.

[0071] Advantageously, the activated carbon layer is applied upstream of the first coarse filter layer.

[0072] Advantageously, the second coarse filter layer and the composite layer are designed as a unit which is materially bonded to one another.

[0073] Advantageously, the pre-filter layer, the activated carbon layer and the composite layer of the filter material have a progressive construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The present invention will be described in detail with reference to the accompanying drawings. Corresponding elements and components have the same reference numerals in the drawings. For greater clarity, the drawings are not drawn to scale.

[0075] In the schematic diagram

[0076] Figure 1 A sectional view showing a first embodiment variant of the filter material,

[0077] Figure 2 A sectional view showing a second embodiment variant of the filter material,

[0078] Figure 3 A sectional view showing a third embodiment variant of the filter material,

[0079] Figure 4 A sectional view showing a fourth embodiment variant of the filter material,

[0080] Figure 5 A view showing a portion of a pleated filter material,

[0081] Figure 6 A spatial schematic diagram of a filter element with filter material is shown. DETAILED DESCRIPTION

[0082] Figure 1A cross-sectional view of a first embodiment variant of a filter material 10 is shown. The flow direction of the air flow is indicated by an arrow L. The filter material 10 has a pre-filter layer 2 on the inflow side, an activated carbon layer 3 in the middle, and a composite layer 1 on the outflow side, which is constructed as a fine filter layer with nanofibers. The composite layer 1 has a plurality of layers, namely a cover layer, a nanofiber layer, and a carrier layer, each of which is connected to each other by material locking. Only the cover layer and the carrier layer are marked in the figure. Other embodiments described below also include this structure of the composite layer 1. The pre-filter layer 2, the activated carbon layer 3, and the composite layer 1 are connected to each other by material locking with a thermoplastic hot melt adhesive (not shown). The cover layer, the nanofiber layer, and the carrier layer of the composite layer 1 can also be connected to each other with a thermoplastic hot melt adhesive or by thermal welding.

[0083] Figure 2 The second embodiment variant of the filter material 10 is shown in section. An inflow-side prefilter layer 2, an outflow-side coarse filter layer 4 with an activated carbon layer 3 applied upstream thereto and a composite layer 1 located therebetween are provided.

[0084] The pre-filter layer 2 and the composite layer 1 are connected to each other by thermal welding. The composite layer 1, the activated carbon layer 3 and the coarse filter layer 4 are connected to each other by material locking with a thermoplastic hot melt adhesive. The cover layer, the nanofiber layer and the carrier layer of the composite layer 1 can be connected to each other by thermoplastic hot melt adhesive or thermal welding.

[0085] Figure 3 The sectional view shows a third embodiment variant of the filter material 10. Here, a prefilter layer 2 on the inflow side, a composite layer 1 on the outflow side and a coarse filter layer 4 located therebetween with an activated carbon layer 3 applied thereto are used, wherein the activated carbon layer 3 is arranged upstream of the coarse filter layer 4.

[0086] The coarse filter layer 4 and the composite layer 1 are connected to each other with a thermoplastic hot melt adhesive. The pre-filter layer 2, the activated carbon layer 3 and the coarse filter layer 4 are connected to each other with a thermoplastic hot melt adhesive. The cover layer, the nanofiber layer and the carrier layer of the composite layer 1 can be connected to each other with a thermoplastic hot melt adhesive or by thermal welding.

[0087] Figure 4 A cross-sectional view of a fourth embodiment variant of the filter material 10 is shown. Figure 3 In contrast to the variant of FIG. 1 , an additional filter layer, namely a coarse filter layer 4 , is used, which is positioned upstream of the composite layer 1 .

[0088] The coarse filter layer 4 and the composite layer 1 are connected to each other by thermal welding. The pre-filter layer 2, the activated carbon layer 3 and the two coarse filter layers 4 are connected to each other by material locking with a thermoplastic hot melt adhesive. The cover layer, the nanofiber layer and the carrier layer of the composite layer 1 can be connected to each other by thermoplastic hot melt adhesive or thermal welding.

[0089] Figure 5The illustration shows a portion of a filter material 10 after pleating, regardless of how many layers it is constructed from. The fold edge 11 is denoted by 11 as an example.

[0090] Figure 6 1 shows a spatial schematic diagram of a filter element 100 having a filter material 10. The filter element 100 having the filter material 10 (which can be as Figures 1 to 4 The structure shown and has been Figure 5 The pleats shown have edge strips 20 attached to the pleated filter material 10 , which contribute to stabilizing the filter element 100 and enable sealing relative to a filter receptacle (not shown here).

[0091] Reference numerals list

[0092] 1 Composite layer with nanofiber layer

[0093] 2 Pre-filter

[0094] 3 Activated carbon layer

[0095] 4 Coarse filter layer

[0096] 10 Filter material

[0097] 11 Folding edges

[0098] 20 Edge band

[0099] 100 Filter elements

[0100] L Air flow direction

Claims

1. A filter material for filtering air in a filter element, comprising an inflow-side prefilter layer (2), an activated carbon layer (3) and a composite layer (1), the composite layer being configured as a fine filter layer with nanofibers, characterized in that: The pre-filter layer (2), the activated carbon layer (3) and the composite layer (1) are connected to each other in a material-locking manner, and The composite layer (1) comprises at least one cover layer, a nanofiber layer and a carrier layer.

2. The filter material according to claim 1, characterized in that The pre-filter layer (2) and / or the composite layer (1) are electrostatically charged.

3. The filter material according to claim 1, characterized in that The activated carbon layer (3) is provided with a permanently sticky adhesive mesh.

4. The filter material according to any one of claims 1 to 3, characterized in that The filter material (10) has an additional coarse filter layer (4).

5. The filter material according to claim 4, characterized in that: The pre-filter layer (2) or the coarse filter layer (4) forms a support for the activated carbon layer (3).

6. The filter material according to any one of claims 1 to 3, characterized in that The activated carbon layer (3) consists of activated carbon particles bonded to each other.

7. The filter material according to any one of claims 1 to 3, characterized in that The filter material (10) has the following structure: A pre-filter layer (2) on the inflow side, a composite layer (1) on the outflow side, and an activated carbon layer (3) located between the pre-filter layer on the inflow side and the composite layer on the outflow side.

8. The filter material according to claim 4, characterized in that The filter material (10) has the following structure: A pre-filter layer (2) on the inflow side, a coarse filter layer (4) on the outflow side, an activated carbon layer (3) applied on the coarse filter layer on the outflow side, and a composite layer (1) located between the pre-filter layer on the inflow side and the activated carbon layer.

9. The filter material according to claim 8, characterized in that The prefilter layer (2) and the composite layer (1) are designed as a unit which is materially connected to one another.

10. The filter material according to claim 4, characterized in that The filter material (10) has the following structure: A pre-filter layer (2) on the inflow side, a composite layer (1) on the outflow side, and at least one coarse filter layer (4) and an activated carbon layer (3) located between the pre-filter layer (2) on the inflow side and the composite layer (1) on the outflow side.

11. The filter material according to claim 10, characterized in that An activated carbon layer (3) is applied upstream to the first coarse filter layer.

12. The filter material according to claim 11, characterized in that The second coarse filter layer and the composite layer (1) are designed as a unit which is materially connected to one another.

13. The filter material according to any one of claims 1 to 3, characterized in that The pre-filtration layer (2), the activated carbon layer (3) and the composite layer (1) of the filter material have a progressive structure.

14. A filter element comprising a filter material according to any one of claims 1 to 13, characterized in that The filter material (10) is pleated and the edge strip (20) or the frame element is attached to the pleated filter material (10).

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