Patent Application
20250099889
This application claims benefit to European Patent Application No. EP 23199850.1, filed on Sep. 26, 2023, which is hereby incorporated by reference herein.
The invention relates to a filter for cleaning an air flow.
Filter elements such as pocket filters, cassette filters, panel filters, edge glue filters or flat filters are known from the prior art. They are used for the filtration of fluids, in particular air. For this purpose, the filter elements are usually inserted into filter housings and locked in place by means of fastening elements, e.g. screwed or latched. To ensure efficient filtration, the connection between the filter and filter frame must have a high degree of tightness. To ensure this, additional seals are usually used. One such filter is described in EP 3 453 441 B1.
US 2016/0 114 275 A1 shows various configurations of filter cartridges that propose a cylindrical filter element and a conical filter element accommodated therein.
DE 10 2013 011 457 A1 describes a filter element for the interior air of a driver's cab of agricultural and work machinery, particularly with sprinkling or spraying devices for pesticides or fertilizers. The interior air filter element comprises an adsorption filter layer with activated carbon, a fine filter layer, particularly for separating aerosols, and a circumferential seal for separating the raw gas side from the clean gas side while being installed in a filter housing.
If the different filter stages consist of different filter elements, each filter element must be securely sealed against the receiving filter housing. When mounting all filter elements, care must also be taken to ensure that the seals of the filter elements are not damaged.
In an embodiment, the present disclosure provides a filter for cleaning an air flow, comprising at least one first filter element for a first filter stage and a second filter element for a second filter stage. The second filter element is provided with a circumferential sealing element. The sealing element is materially connected to the second filter element. The sealing element includes an outer circumferential sealing surface configured for sealing with respect to a filter receptacle and an inner circumferential sealing surface configured for sealing with respect to the first filter element.
Subject matter of the present disclosure will be described in even greater detail below based on the exemplary figures. All features described and/or illustrated herein can be used alone or combined in different combinations. The features and advantages of various embodiments will become apparent by reading the following detailed description with reference to the attached drawings, which illustrate the following:
In an embodiment, the present invention provides a filter having at least two filter elements for at least two filter stages, which is manufactured using a minimum amount of material and which enables simple and secure mounting in a filter receptacle.
According to the present disclosure, it was recognized as advantageous to provide a sealing element which permits a sealing of the first filter element to the second filter element and a sealing of the second filter element to the filter receptacle.
The filter is used to clean an air flow with at least a first filter element for a first filter stage and a second filter element for a second filter stage. The second filter element is provided with a circumferential sealing element which is materially connected to the second filter element. The material connection of the circumferential seal can be realized, for example, by bonding or by integrated production, so that a secure seal between the filter element and the filter receptacle can be ensured.
According to the present disclosure, the sealing element has at least one external, circumferential sealing surface for sealing against a filter receptacle. The shape of the sealing surface thus corresponds to the shape of the filter receptacle. The filter receptacle can be a filter housing or an air duct. The external, circumferential sealing surface is used for radial sealing of the filter relative to the filter receptacle. Radial thereby means radial to the extent and the flow direction of the filter.
The sealing element has an opening in the middle through which the fluid to be filtered flows during filtration, the opening having an internal, circumferential sealing surface for sealing against the first filter element. The sealing element is therefore shaped in such a way that it surrounds both the first filter element and the second filter element in a frame-like manner. With just one sealing element, the first filter element is thus sealed to the second filter element and the second filter element is sealed to the filter holder.
In an advantageous embodiment of the invention, the first filter element is accommodated in a press seat in the sealing element and the internal sealing surface lies against the first filter element with a press fit.
The inner sealing surface of the sealing element is preferably formed by a sealing lip.
In an undeformed state, i.e. before the first filter element is inserted into the seal, the sealing lip can have an overlap of at least 1 millimeter relative to the mating surface of the first filter element. The sealing element and the first filter element are friction-locked together. For this purpose, the fit between the sealing element and the first filter element is selected in such a way that a press fit is ensured. A press fit can also be referred to as an interference fit. The press fit ensures that the first filter element is held securely in its mounting position, even under mechanical stress during operation.
It has been found that it is advantageous to provide the sealing element with a circumferential compensation groove configured as a circumferential depression arranged on the inflow side. The compensation groove can advantageously reduce restoring forces. In particular, the combination of sealing lip and compensation groove contributes to a leakage-free installation of the filter with very high tightness.
In an embodiment, the sealing element can be injection-molded onto the second filter element, i.e. configured as an injection-molded part made of injection-moldable material, in particular polyurethane or silicone.
It has been found that a Shore hardness A greater than 20 of the sealing element material provides a good seal. In particular, the Shore hardness A can be in the range 20 to 50, with standardized measurements according to DIN ISO 7619-1 or ISO 868 or ASTM D2240.
In an embodiment of the filter, the first filter element and, if applicable, also the second filter element is configured as a bellows made of a pleated filter medium and provided with edge strips all around. If the filter element has a rectangular shape when viewed from above, it is provided with edge strips on its four sides. The first filter element is configured in such a way that it has a certain inherent rigidity so that the circumferential edge strips fit snugly against the inner sealing surface and are not deformed by the sealing surface.
In an embodiment of the filter, the edges of the two end pleats of the filter medium of the first filter element are oriented towards an inflow side of the filter. If an air flow to be cleaned flows through the first filter element, the air flow pushes the respective end pleat of the filter medium and the edge strip radially outwards and a corresponding force is exerted on the sealing element.
In an embodiment of the filter, the first filter element is configured as a particle filter element and/or the second filter element is configured as an adsorption filter element. The adsorption filter element can, for example, have activated carbon as the adsorbent.
The present disclosure also relates to a filter assembly with a filter as described above and a filter housing for accommodating the filter.
In an embodiment of the filter assembly, it has a frame-shaped cap that can be connected to the filter housing or, alternatively, a housing upper part as part of the filter housing, each of which serves to fix the filter in the filter housing. This also prevents the first filter element from slipping out of the sealing element.
The present disclosure also relates to the use of a filter assembly as described above as an interior air filter assembly for filtering and cleaning the cabin inlet air in a vehicle or as an inlet air filter in a fuel cell unit.
In the interior air filter assembly, the cabin air is filtered and cleaned in a vehicle that may be subject to increased pollution, particularly in a commercial vehicle, a heavy-duty vehicle or an off-road vehicle. The vehicles can be, for example, trucks, construction machinery, rollers, tracked vehicles, road milling machines, bulldozers, tracked loaders, excavators, cranes, harvesting machines, agricultural machinery, combine harvesters, chaff cutters, tractors, self-propelled field sprayers, forestry vehicles or similar.
The embodiments of the invention described and the advantageous further embodiments of the invention described represent advantageous further embodiments of the invention also in combination with one another, insofar as this is technically expedient.
Regarding further advantages and constructively and functionally advantageous embodiments of the invention, reference is made to the description of the exemplary embodiments with reference to the accompanying figures.
Embodiments of the invention will be explained in more detail with reference to the attached figures. Corresponding elements and components are provided with the same reference numbers in the figures. For the sake of clarity, the figures have not been drawn to scale.
The circumferential sealing element 3 is materially connected to the second filter element 2, e.g. bonded. The circumferential sealing element 3 has a further sealing surface, namely an external sealing surface 4. This serves to seal the filter 10 against a filter receptacle 20.
An air flow L flows through the filter 10 from an inflow side A to an outflow side B and the air flow L is cleaned in the process.
The circumferential sealing element 3 has a compensation groove 7, i.e. a depression, on its inflow side.
In order to hold the filter 10 with the first filter element 1 securely in the filter receptacle 20, even in the event of vibrations, a cap 30 is provided, which, after the mounting of the filter 10, is attached to the filter receptacle 20. As indicated in the figure, the cap 30, the circumferential sealing element 3 and the filter receptacle 20 can be screwed together.
While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23199850.1 | Sep 2023 | EP | regional |
