Patent Application
20240325962
This application claims foreign priority benefits under 35 U.S.C. ยง 119 (a)-(d) to European patent application number EP 23164329.7, filed Mar. 27, 2023, which is incorporated by reference in its entirety.
The present disclosure relates to an air filter arrangement and to a method of replacing a plurality of used filter elements.
In the not yet published European patent application no. 22 184 913.6, a fresh air device with a filter unit attached to it, which is configured to clean a bitumen-containing volume flow, is de-scribed for a road paver. The filter unit has a filter housing as well as several filter elements, which are accommodated individually in a predetermined sequence one behind the other in the filter housing. With such a multi-part structure, replacing the filter elements involves a relatively high level of effort. When replacing the filter, the filter housing must in fact first be opened using a suit-able tool. Then the respective filter elements must be removed piece by piece, that is, individually one after the other, and disposed of. Furthermore, before installing new filter elements, it is often necessary to clean the filter housing, in particular the receptacles provided for the respective filter elements. The new filter elements can then be installed individually one after the other to finally close the housing. In total, this results in several work steps that delay the actual installation process on the construction site. The time required for this leads in particular to undesirable down-times on the construction site, which can cause the installation material to cool down. Due to the handling of the filter replacement process described above, it can also occur that the new filter elements are installed in the housing in the wrong order, which means that the desired filter effect can no longer be achieved. When installing several individual filter elements, there is in particular the risk that a fine particle filter that is actually provided as a downstream filter stage is inadvertently installed as a pre-filter, i.e., as an inlet filter stage. At this point, a filter cake can easily form on the surface of the fine particle filter, which can clog the intake path. An incorrect order of the filter elements can therefore also have a negative effect on the fan unit connected to the filter unit.
An object of the disclosure is to provide a better manageable air filter arrangement for construction site use with regard to the problem described above, which can be reliably installed and dis-mantled on the construction site within a short time for cleaning a bitumen-containing volume flow.
This problem is solved by means of an air filter arrangement according to the disclosure and by means of a method according to the disclosure.
The disclosure relates to an air filter arrangement for cleaning a bitumen-containing volume flow, wherein the air filter arrangement comprises at least one first filter element and at least one second filter element, which are arranged as filter elements acting in succession for cleaning the bitumen-containing volume flow. According to the disclosure, the first filter element and the second filter element are firmly connected to one another. This results in a fixed connection of several filter elements to form a filter unit. Such a filter unit can be preferably used on a fresh air device on a road construction site to filter bitumen-containing vapors and/or aerosols from the air in several filter stages and to provide the purified air flow obtained from this as fresh air at a workplace.
In accordance with the disclosure, a connection is made between the two filter elements, by means of which the two filter elements are held together with a predetermined holding force. The two filter elements are thus not present as separate individual parts, but together form an inseparable unit. This means that the two filter elements, which may have different filter properties, can be removed and installed in one piece.
In the air filter arrangement according to the disclosure, the two filter elements are not present as individual filters arranged in series one behind the other in separate form. Rather, the air filter arrangement according to the disclosure forms a coherent composite of individual filter elements. As a result, the respective filter elements are better manageable together, can be removed in particular in one piece and can be replaced with new filter elements joined together according to the disclosure with little effort. This reduces the time required to replace filters on the construction site and makes filter replacement easier and less error-prone overall.
The fact that the two filter elements of the air filter arrangement according to the disclosure are firmly connected to one another also results in a compact overall structure of the air filter arrangement. Such a one-piece air filter arrangement consisting of several filter elements can be installed in a better way, especially in places that are difficult to access, for example behind a control panel or overhead.
Preferably, the two filter elements are connected to one another by a material bond, form-fit and/or force-fit connection. It would be conceivable to join the two filter elements together at their outer edges facing each other by fusing and by the resulting intermolecular or chemical bonding forces, if necessary by means of additives. In particular, a welding, soldering or adhesive connection joining the filter elements together could be considered for this purpose. Preferably, the first filter element and the second filter element are glued together. This allows the two filter elements to form a robust unit.
One variant provides that the edges of the respective filter elements facing each other and formed on the outside are glued together all around in an airtight manner. Separation points between the filter elements glued together in such a way do not need to provide any further sealing. An adhesive strip applied for this purpose can hold the two filter elements together such that they can only be separated by cutting the adhesive strip.
In particular, an airtight coating is formed at least in some areas by external walls of the joined filter elements. This coating fulfills the function of a filter housing so that no separate housing is required to attach the air filter arrangement. This means that the two filter elements form a housing for the air filter arrangement due to their combined shell surface.
It is conceivable that the air filter arrangement as a whole could be configured as a one-piece clip-on module for tool-free attachment to a fan unit. In particular, the air filter arrangement is a stable filter unit made up of several filter elements, which does not require a separate filter housing. In this case, the outer walls of the combined filter elements can themselves form the housing of the air filter arrangement. This reduces the amount of cleaning required on the construction site, as separate housing structures, in particular housings for receiving individual filter elements, always provide a surface for contamination. A clip-on module such as this can in particular be disposable.
According to one embodiment of the disclosure, the first filter element and/or the second filter element has a zigzag-shaped, undulating, rectangular, nub-shaped and/or pyramid-shaped filter mesh. This allows the filter surface of the filter element(s) to be enlarged. It would be conceivable for the first filter element and/or the second filter element to form a filter surface that is present as a filter profile with heights and depths. In the assembled state of both filter elements, the respective profiles can be aligned with each other such that their heights and depths are offset from each other. It would be conceivable that the filter profile is configured in the form of a nubby profile or a pyramid profile. A particularly large filter surface, despite limited installation space, is achieved if both filter elements have a zigzag-shaped, undulating, rectangular filter mesh and/or the filter profile described above. The filtering of aerosols from the bitumen-containing volume flow passing through them can be carried out reliably by the two filter elements in particular if their mutually facing filter structures are aligned offset to one another in the direction of the volume flow. This allows the filter effect to be maximized; in particular, aerosols that are not bound by the first filter element can be bound by the filter element positioned behind it.
In addition, the filter properties can be improved if the first filter element and/or the second filter element is an activated carbon filter. Aerosols can be bound particularly effectively by means of activated carbon contained in the filter elements.
Preferred filtration of the bitumen-containing volume flow results from the fact that the two filter elements are identical filter elements, that is, they have comparable filter properties, for example two zigzag-shaped activated carbon filters joined together. This also results in advantages for recycling.
It would be useful if the air filter arrangement included a third filter element as a pre-filter, which is firmly or detachably connected to the first and second filter elements, preferably glued to them. Regardless of whether the pre-filter is firmly or detachably connected to the two filter elements, it can be removed and installed in one piece together with the first and second filter elements. Such an air filter arrangement formed in three layers saves even more time during a filter replacement if it is manageable in one piece during installation and removal. Above all, this makes it easier to replace filters in places that are difficult to access, for example behind or underneath a console.
A robust unit consisting of the three individual filter elements is created in particular by gluing these filter elements together. Such a three-layer bonded unit consisting of the respective filter elements can be attached to a fan unit in one piece. However, it would be conceivable for the third filter element to be detachably coupled to the other two filter elements for long-term use, so that the third filter element used as a pre-filter can be replaced earlier than the other two filter elements.
One variant provides that the third filter element has a smooth surface. This allows the third filter element used as a pre-filter to be easily cleaned. For example, a film of coarse particles that has collected on the smooth surface, known as filter cake in specialist circles, can be easily wiped off the smooth surface. It would be conceivable for the third filter element to be a foam filter. Such a filter element can be used very well as a coarse particle filter at the foremost position of the air filter arrangement. As an alternative to a foam filter, a fleece filter could also be considered.
According to one embodiment of the disclosure, the respective filter elements are present as filter layers arranged one above the other. Accordingly, the air filter arrangement has a layered structure comprising several filter elements, resulting in a compact structure. In particular, the respective filter elements can be in the form of filter mats arranged one above the other.
Preferably, the air filter arrangement forms an inlet side and an outlet side, wherein a sealing element is provided on the inlet side and/or on the outlet side. The sealing element enables the air filter arrangement to be attached to a fan unit in a sealing manner. The sealing element is provided in particular as a rubber lip or rubber bead and can be glued to the edge of the externally positioned filter element, in particular to the edge of the externally positioned, zigzag-shaped activated carbon filter. In the case of a round filter shape, the sealing element can be provided as a rubber ring.
Preferably, the sealing element is configured in the form of a latching element for tool-free attachment to a fan housing. In this variant, the sealing element also has the function of serving as a fastening means for attaching the air filter arrangement.
One variant provides that the sealing element forms a tapered bead that can be pressed against a housing surface of a fan unit as a sealing lip. The sealing element can form a projection configured as a latching means or latching element that can be held against a housing projection of the fan unit when pulled. It would be conceivable for the sealing element to be pushed onto the filter element forming the outlet side by means of a press fit, in particular onto the zigzag-shaped activated carbon filter positioned at the outlet.
A particularly dimensionally stable air filter arrangement suitable for three-stage filtration results from the fact that the three interconnected filter elements form a shell surface as a result of their assembly, which is present as an airtight coating. This coating can be made of the same material as a material used for gluing the respective filter elements. Such a coating also serves as weather protection and ensures that no weather-related moisture accumulates in the filter elements. A coating formed by the joined shell surfaces of the three filter elements simultaneously forms a flow channel for the bitumen-containing air that is sucked in or blown through.
It would be conceivable for the airtight coating to be created by an outer mesh structure of the filter elements. The outer walls of the filter elements have a mesh structure with high impermeability, but can essentially be made of the same mesh material as the filter structure.
According to one embodiment, an externally formed, extended wall section of the central filter element is available as a receptacle for the filter element used as a pre-filter on the air filter arrangement. For example, a foam filter provided as a pre-filter could be placed in this receptacle with a press fit. This would allow the pre-filter to be attached to the other two, preferably similar, filter elements without a material connection and could be easily separated from them for recycling or simply to be replaced.
It is practical if the firmly connected filter elements together form a self-supporting air filter arrangement. Separate holders are therefore not required for positioning the air filter arrangement.
The disclosure moreover relates to a fan unit with a fan housing that forms an intake opening to which an air filter arrangement according to the disclosure is detachably attached. The air filter arrangement according to the disclosure can be attached directly to the intake opening of the fan housing without being received within a fan or filter housing. For example, a sealing element attached to the outlet side of the air filter arrangement forms a latching element that can be pressed into a depression formed at the intake opening on the fan housing in order to fasten the air filter arrangement to the fan housing with a desired holding force. A sealing effect already achieved by the assembly can be further reinforced during operation by the intake of air through the air filter arrangement, so that the air filter arrangement remains securely attached to the fan unit.
A fresh air system for a road construction machine, which is in the form of a road paver or a feed-er vehicle for a road paver, which has at least one fan unit with an air filter arrangement detachably attached thereto in accordance with the disclosure, would be expedient. The air filter arrangement forms a quickly and easily installable and removable unit for a fresh air system provided on the road paver or feeder vehicle.
It would be conceivable for the road construction machine to have a (driver's) seat console with a preferably pivotably mounted console base, on the underside of which the fan unit and the air filter arrangement attached to it are arranged. As a pivoting console, the console base is located out-side a driver's operating platform of the road construction machine when pivoted outwards, so that the air filter arrangement can be installed or removed in its entirety overhead by an operator positioned underneath.
It would be conceivable for the air filter arrangement according to the disclosure to be used in another fresh air system of the road construction machine, e.g., in a fresh air system of a control panel. For example, the air filter arrangement could be arranged behind a driver's control panel. With this arrangement, it is also preferred that the air filter arrangement according to the disclosure can be installed and removed in one piece. The used air filter arrangement can thereby simply be removed downwards from the fan unit. Conversely, a new air filter unit as a whole can easily be attached to the fan unit in place of the used air filter arrangement.
Furthermore, the disclosure relates to a method for replacing a plurality of used filter elements of a fresh air system provided on a road paver or on a feeder vehicle, which are used as filter elements acting in sequence for cleaning a bitumen-containing volume flow. The method according to the disclosure provides that the plurality of used filter elements are firmly connected to one an-other, removed together and a plurality of new, firmly connected filter elements are installed in their place. According to the disclosure, several filter elements can always be installed and re-moved at the same time and therefore do not need to be installed or removed as individual parts piece by piece. This enables simple installation and removal with just a few hand movements within a short time. The fact that the method according to the disclosure allows several filter elements to be installed and removed at once, that is, assembled in one piece, also means that proper use of the filter elements or proper installation of the filter elements can be achieved in a better way.
The disclosure is explained in more detail with reference to the embodiments shown in the following Figures:
Identical technical features are provided with the same reference signs throughout the Figures.
Outer wall sections a, b of the two filter elements 2, 3, which are firmly connected to each other, together form an airtight coating 6. This coating 6 extends essentially over the entire shell surface created by the two filter elements 2, 3.
In
The third filter element 11 can be detachably or firmly connected to the other two filter elements 2, 3. It would be conceivable for the third filter element 11 to be clamped in a receptacle 13 by a press fit, wherein the receptacle 13 is formed by an extended wall section c of the central filter element 3. A purely form-fitting attachment of the pre-filter, for example to a tapered cross-section of the central filter element 3, would be conceivable as an alternative. Alternatively, the second, i.e., central filter element 3 can be formed without a receptacle 13 and the third filter element 11 is glued to it along an edge zone 14.
The air filter arrangement 1 also has a sealing element 15. In
According to
According to
According to
In the swiveled-out position of the driver's seat console 23 shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 23164329.7 | Mar 2023 | EP | regional |
