Fresh air system with air filter assembly and method for replacing multiple filter elements

Abstract

The invention relates to an air filter arrangement (1) for cleaning a bitumen-containing volume flow (V), comprising at least a first filter element (2) and a second filter element (3), which are arranged as sequentially acting filter elements (2, 3) for cleaning the bitumen-containing volume flow (V), wherein the first filter element (2) and the second filter element (3) are rigidly connected to each other. The invention further relates to a method for performing the replacement of several filter elements (2, 3).

Description

[0001] The present invention relates to an air filter arrangement according to claim 1 and to a method for replacing a plurality of used filter elements according to claim 15.

[0002] The unpublished European patent application No. 22 184 913.6 describes a fresh air system for a road paver with an attached filter unit designed to clean a bitumen-containing flow. The filter unit comprises a filter housing and several filter elements, which are individually inserted one after the other in a predetermined sequence within the filter housing. With such a multi-part design, changing the filter elements is a relatively complex process. To change the filters, the filter housing must first be opened with a suitable tool. Then, the individual filter elements must be removed and disposed of one by one. Furthermore, before installing new filter elements, it is often necessary to clean the filter housing, particularly the recesses for the individual filter elements.Afterwards, the new filter elements can be installed individually, one after the other, to finally close the housing. This results in several work steps that delay the actual installation process on the construction site. The time required leads to undesirable downtime on the site, which can cause the installation material to cool down. Due to the handling of the filter replacement process described above, it also happens that the new filter elements are installed in the housing in the wrong order, thus failing to achieve the desired filtration effect. When installing several individual filter elements, there is a particular risk that a fine particle filter intended as a downstream filter stage will be mistakenly installed as a pre-filter, i.e., as an inlet filter stage.A filter cake can easily form on the surface of the fine particle filter at this point, potentially clogging the intake path. An incorrect order of the filter elements can therefore also negatively affect the fan unit connected to the filter unit.

[0003] The object of the invention is to provide a more manageable air filter arrangement for use on construction sites, in view of the problem described above, which can be installed and dismantled on the construction site within a short time, reliably for cleaning a bitumen-containing volume flow.

[0004] This problem is solved using an air filter arrangement according to claim 1 and by means of a method according to claim 15.

[0005] Advantageous further developments of the invention are given by the respective subject matter of the dependent claims.

[0006] The invention 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 sequentially acting filter elements for cleaning the bitumen-containing volume flow. According to the invention, the first filter element and the second filter element are rigidly connected to one another. This results in a rigid connection of several filter elements to form a filter unit. Such a filter unit can be advantageously used on a road construction site at a fresh air supply system to filter bitumen-containing vapors and / or aerosols from the air in several filter stages and to provide the resulting cleaned airflow as fresh air at a workplace.

[0007] According to the invention, a connection is established between the two filter elements, by which the two filter elements are held together with a predetermined holding force. The two filter elements are therefore not separate individual parts, but together form an inseparable unit. This allows the two filter elements, which may have different filter properties, to be removed and installed as a single unit.

[0008] In the air filter arrangement according to the invention, the two filter elements are not arranged as separate individual filters in a series. Rather, the air filter arrangement according to the invention forms a cohesive unit of individual filter elements. This makes the individual filter elements easier to handle together, allows them to be removed as a single unit, and enables them to be replaced with new filter elements assembled according to the invention with minimal effort. This reduces the time required for filter changes on the construction site and makes filter changes simpler and less prone to errors overall.

[0009] Because the two filter elements are firmly connected to each other in the air filter assembly according to the invention, the overall design of the air filter assembly is also compact. Such a one-piece air filter assembly, assembled from several filter elements, can be installed more easily, especially in hard-to-reach places, for example behind a control panel or overhead.

[0010] Preferably, the two filter elements are connected to each other by a material-bonded, form-fit, and / or force-fit connection. It would be conceivable to connect the two filter elements at their facing outer edges by fusing them and by the resulting intermolecular or chemical bonding forces, optionally via additives. In particular, a welding, soldering, or adhesive bond joining the filter elements would be suitable for this purpose. Preferably, the first filter element and the second filter element are bonded together. This allows the two filter elements to form a robust unit.

[0011] One variant involves bonding the facing, outwardly formed edges of the respective filter elements together airtight all around. Such bonded joints between the filter elements require no further sealing. An adhesive strip applied for this purpose can hold the two filter elements together in such a way that they can only be separated by destroying the adhesive strip.

[0012] In particular, the outer walls of the joined filter elements form an airtight enclosure, at least in some areas. This enclosure functions as a filter housing, eliminating the need for a separate housing to mount the air filter assembly. This means that the two filter elements, through their combined outer surface, form a housing for the air filter assembly.

[0013] It is conceivable that the entire air filter assembly could be configured as a single-piece, attachable module for tool-free installation on a fan unit. Specifically, the air filter assembly could be a self-contained, stable filter unit comprised of several filter elements, eliminating the need for a separate filter housing. The outer walls of the assembled filter elements could themselves form the housing of the air filter assembly. This reduces cleaning effort on the construction site, as separate housing structures, especially those for individual filter elements, always provide a surface for contamination. Such an attachable module could also be a disposable item.

[0014] According to one embodiment of the invention, the first filter element and / or the second filter element has a zigzag, wavy, rectangular, studded, and / or pyramidal filter fabric. This increases the filter area of ​​the filter element(s). It is conceivable that the first filter element and / or the second filter element forms a filter surface that is a filter profile with heights and depths. When both filter elements are assembled, the respective profiles can be aligned with each other such that their heights and depths are offset. It is conceivable that the filter profile is designed in the form of a studded profile or a pyramidal profile.A particularly large filter area, despite limited installation space, is achieved when both filter elements have a zigzag, wave-shaped, rectangular filter fabric and / or the filter profile described above. The filtering of aerosols from the bituminous volume flow passing through them can be reliably accomplished by the two filter elements, especially when their opposing filter structures are oriented offset from each other in the direction of the volume flow. This maximizes the filter effect; in particular, it ensures that aerosols not captured by the first filter element are captured by the filter element positioned behind it.

[0015] The filter performance can be further improved by using activated carbon filters in the first and / or second filter element. The activated carbon contained in the filter elements binds aerosols particularly effectively.

[0016] Advantageous filtration of the bitumen-containing volume flow is achieved by using identical filter elements, i.e., having comparable filter properties, for example, two joined, zigzag-shaped activated carbon filters. This also offers advantages for recycling.

[0017] It would be advantageous for the air filter assembly to include a third filter element as a pre-filter, which is permanently or detachably connected to the first and second filter elements, preferably bonded to them. Regardless of whether the pre-filter is permanently or detachably connected to the two filter elements, it can be removed and installed together with the first and second filter elements as a single unit. Such a three-layer air filter assembly saves even more time during filter changes if it can be handled as a single unit during installation and removal. Above all, this facilitates filter changes in hard-to-reach places, for example, behind or below a console.

[0018] A robust unit consisting of the three individual filter elements is achieved primarily through their bonding. Such a three-layer adhesive composite of individual filter elements can be attached to a fan unit as a single unit. However, it would be conceivable for the third filter element to be detachably connected to the other two for long-term use, allowing the third filter element, which acts as a pre-filter, to be replaced sooner than the other two.

[0019] One option involves using a third filter element with a smooth surface. This allows for easy cleaning of the third filter element, which acts as a pre-filter. For example, a film of coarse particles, known in technical circles as filter cake, that accumulates on the smooth surface can be easily wiped away. It would also be conceivable for the third filter element to be a foam filter. Such a filter element can be very effectively used as a coarse particle filter at the front of the air filter assembly. Alternatively, a fleece filter could also be used instead of a foam filter.

[0020] According to one embodiment of the invention, the respective filter elements are arranged as filter layers on top of one another. The air filter assembly thus has a layered structure consisting of several filter elements, resulting in a compact design. In particular, the respective filter elements can be in the form of filter mats arranged on top of one another.

[0021] Preferably, the air filter assembly forms an inlet side and an outlet side, with a sealing element provided on the inlet side and / or the outlet side. The sealing element enables the air filter assembly to be securely attached to a fan unit. The sealing element is, in particular, a rubber lip or rubber bead and can be adhered to the edge of the externally positioned filter element, especially the edge of the externally positioned, zigzag-shaped activated carbon filter. In the case of a round filter shape, the sealing element can be a rubber ring.

[0022] Preferably, the sealing element is designed as a snap-in element for tool-free attachment to a fan housing. In this variant, the sealing element simultaneously serves as a fastening element for attaching the air filter assembly.

[0023] One variant involves the sealing element forming a tapered bead that can be pressed against a housing surface of a fan unit, acting as a sealing lip. The sealing element can also have a projection configured as a locking element, which can be held in place by tension against a housing projection of the fan unit. It is conceivable that the sealing element is press-fitted onto the filter element forming the outlet side, particularly onto the outlet-positioned, zigzag-shaped activated carbon filter.

[0024] A particularly dimensionally stable air filter assembly suitable for three-stage filtration is achieved by assembling the three interconnected filter elements to form a sheath that acts as an airtight casing. This casing can be made of the same material used to bond the individual filter elements. Such a casing also serves as weather protection, preventing the accumulation of moisture within the filter elements. The sheath formed by the joined surfaces of the three filter elements simultaneously creates a flow channel for the intake or exhaust of bitumen-containing air.

[0025] It is conceivable that the airtight casing is achieved through an outer fabric structure of the filter elements. The outer walls of the filter elements have a highly dense fabric structure, but can essentially be made of the same fabric material as the filter structure itself.

[0026] According to one embodiment, an externally formed, extended wall section of the central filter element serves as a receptacle for the filter element used as a pre-filter in the air filter assembly. A foam filter, for example, designed as a pre-filter, could be press-fitted into this receptacle. This would allow the pre-filter to be attached to the other two, preferably identical, filter elements without a material bond and to be easily separated from them for recycling or simple replacement.

[0027] It is advantageous if the filter elements, which are permanently connected to each other, together form a self-supporting air filter assembly. Separate brackets are therefore not required for positioning the air filter assembly.

[0028] The invention further relates to a fan unit with a fan housing that forms an intake opening to which an air filter assembly according to the invention is detachably attached. The air filter assembly according to the invention can be attached directly to the intake opening of the fan housing without being contained within a fan or filter housing. For example, a sealing element attached to the outlet side of the air filter assembly forms a snap-in element that can be pressed into a recess formed at the intake opening of the fan housing in order to attach the air filter assembly to the fan housing with a desired holding force. A sealing effect already achieved by the assembly can be further enhanced during operation by the intake of air through the air filter assembly, so that the air filter assembly remains securely attached to the fan unit.

[0029] A fresh air system for a road construction machine, in the form of a paver or a feeder vehicle for a paver, would be advantageous, comprising at least one fan unit with a detachably attached air filter assembly according to the invention. The air filter assembly forms a unit that can be quickly and easily installed and removed for a fresh air system provided on the paver or feeder vehicle.

[0030] It would be conceivable for the road construction machine to have a (driver's) seat console with a console base, preferably mounted on a pivot, on the underside of which the fan unit, including the attached air filter assembly, is arranged. As a pivoting console, the console base, when pivoted outwards, is located outside the operator's platform of the road construction machine, allowing the entire air filter assembly to be installed or removed overhead by an operator positioned underneath.

[0031] It is conceivable that the air filter assembly according to the invention could be used in another fresh air system of the road construction machine, for example, in the fresh air system of an operator panel. For instance, the air filter assembly could be located behind a driver's control panel. In this arrangement as well, it is advantageous that the air filter assembly according to the invention can be installed and removed as a single unit. The used air filter assembly can simply be pulled downwards off the fan unit. Conversely, a new air filter assembly can easily be attached to the fan unit in place of the used one.

[0032] Furthermore, the invention relates to a method for replacing a plurality of used filter elements in a fresh air system provided on a road paver or a feeder vehicle, which are used as sequentially acting filter elements for cleaning a bitumen-containing volume flow. The method according to the invention provides that the plurality of used filter elements are permanently connected to one another, removed together, and replaced by a plurality of new, permanently connected filter elements. According to the invention, several filter elements can thus always be installed and removed at once, eliminating the need to assemble or remove them piece by piece as individual parts. This enables simple installation and removal with just a few steps within a short time.Because several filter elements can be installed and removed at once, i.e., assembled in one piece, in the method according to the invention, it is also easier to achieve proper use or installation of the filter elements.

[0033] The invention will be explained in more detail with reference to the exemplary embodiments shown in the following figures. These show: Fig. 1 an air filter arrangement according to the invention, Fig. 2 a road construction machine in the form of a road paver, Fig. 3 a road construction machine in the form of a feeder vehicle for a road paver, Fig. 4 a seat console with a fresh air device, and Fig. 5 a control panel with a fresh air device.

[0034] Identical technical features are consistently identified in the figures using the same reference symbols.

[0035] Figure 1Figure 1 shows an air filter assembly 1 for cleaning a bitumen-containing volume flow V flowing in direction R through the air filter assembly 1. The air filter assembly 1 has a first filter element 2 and a second filter element 3. The first and second filter elements 2, 3 are arranged directly above one another and have mutually facing, firmly connected edges 4, 5. The mutually facing edges 4, 5 of the two filter elements 2, 3 can, for example, be bonded together airtight.

[0036] The outer wall sections a, b of the two filter elements 2, 3, which are firmly connected to each other, together form an airtight casing 6. This casing 6 extends essentially over the entire surface area of ​​the casing created by the two filter elements 2, 3.

[0037] In Figure 1The two filter elements 2, 3 are each an activated carbon filter with a zigzag-shaped filter fabric 7, 8. The opposing tips 9, 10 of the two filter elements 2, 3 are positioned side by side, offset in the direction of flow R. This means that the respective tips 9 of the first filter element 2 lie between the respective adjacent tips 10 of the second filter element 3 in the flow direction R, and vice versa. This allows aerosols from the volume flow V to be bound more reliably in the filter fabric 7, 8 via the two filter elements 2, 3. This also means that the two filter elements 2, 3 wear more uniformly.

[0038] Figure 1 Figure 1 further shows that the air filter assembly 1 includes a third filter element 11, which serves as a pre-filter for the air filter assembly 1. The third filter element 11 can, for example, be a foam filter with a smooth surface 12 that is easy to clean.

[0039] The third filter element 11 can be detachably or permanently connected to the other two filter elements 2 and 3. One possibility is that the third filter element 11 is clamped in a receptacle 13 by a press fit, the receptacle 13 being formed by an extended wall section c of the middle filter element 3. Alternatively, a purely form-fit attachment of the pre-filter, for example to a tapered cross-section of the middle filter element 3, would be conceivable. Another alternative is that the second, i.e., middle, filter element 3 could be formed without a receptacle 13, and the third filter element 11 could be bonded to it along an edge zone 14.

[0040] The air filter assembly 1 also has a sealing element 15. Figure 1 The sealing element 15 is provided on an outlet side A of the air filter assembly 1. It would be conceivable that a comparable sealing element 15 is attached to an inlet side E of the air filter assembly. According to Figure 1 The sealing element 15 simultaneously serves as a snap-in element with a projection 16, which acts as a snap-in means to engage the sealing element 15 with a fan housing 40 (see Figure 5 ) to attach.

[0041] According to Figure 1 In the air filter arrangement 1 shown therein, the respective filter elements 2, 3, and 11 are arranged as filter layers S1, S2, and S3, one above the other. The third filter element 11, which functions as a pre-filter at the bottom, is configured, for example, as a coarse particle filter. The filter layers S1 and S2 arranged above it each form activated carbon fine particle filters. Together, the filter elements 2, 3, and 11 thus act sequentially to clean the bitumen-containing volume flow V in the direction R.

[0042] Figure 2Figure 17 shows a road construction machine, which is in the form of a road paver 18. The road paver 18 is configured to produce a new paving layer 22 from paving material 20 stored within a material hopper 19, using its screed 21. The road paver 18 is made of Figure 2 is controlled by a driver F. The driver F sits on a swiveled-out driver's seat console 23, which has a swiveling console base 24. In Figure 2 This console base 24 is positioned laterally, swivelling out over a driver's operating platform 25. To control the operation of the road paver 18, the driver F uses a driver's control panel 26.

[0043] Figure 3 Figure 27 shows another road construction machine, configured as a feeder vehicle 28. In practice, such a feeder vehicle 28 is used to supply a road paver 18 according to... Figure 2to supply with paving material 20. For this purpose, the feeder vehicle 28 drives in the direction of travel in front of the road paver 18 and throws paving material 20 into the material hopper 19 of the road paver 18 following behind it by means of a conveying device 29 fitted to the feeder vehicle 28.

[0044] According to Figure 3 The feeder vehicle 28 has a driver's control panel 30. In front of this is a seat console 31 with a swiveling console base 32. The driver's control panel 30 is in Figure 3 Positioned behind a windshield of the feeder vehicle 28, it can, however, together with the seat console 31, be brought into a position next to the driver's control station, i.e., swivel beyond its driver's control platform like the seat console from 23. Figure 2 .

[0045] Figure 4Figure 1 shows the (driver's) seat console 23, 31 in an isolated view. The (driver's) seat console 23, 31 includes a fresh air system 33 with several nozzle units 34, 35, which are provided on both sides of the (driver's) seat console 23, 31. A fan unit 36 ​​is mounted on the underside of the console base 24, 32. The air filter assembly 1 is attached to the fan unit 36. The fan unit 36 ​​and the air filter assembly 1 are contained within a stage 37 formed by the console base 24, 32.

[0046] In the Figure 2 In the shown swung-out position of the driver's seat console 23, an operator can remove the air filter assembly 1 in one piece from below the driver's seat console 23 overhead and replace it with a new air filter assembly 1.

[0047] Figure 5Figure 26, 30 shows the driver control panel in an isolated view with a fresh air system 38 provided thereon, which includes a fan unit 39, to whose fan housing 40 the air filter assembly 1 is attached. Even in this position, the one-piece, i.e., continuous, construction of the air filter assembly 1 is very advantageous for installation and removal.

Claims

1. Air filter arrangement (1) for cleaning a bitumen-containing volume flow (V), comprising at least a first filter element (2) and a second filter element (3), which are arranged as successively acting filter elements (2, 3) for cleaning the bitumen-containing volume flow (V), characterized in that the first filter element (2) and the second filter element (3) are firmly connected to one another.

2. Air filter arrangement according to claim 1, characterized in that the first filter element (2) and the second filter element (3) are connected to one another by a material-locking, positive-locking and / or non-positive connection, preferably glued to one another.

3. Air filter arrangement according to claim 1 or 2, characterized in that the first filter element (2) and / or the second filter element (3) has a zigzag-shaped, wave-shaped, rectangular, knob-shaped or pyramid-shaped filter fabric (7, 8).

4. Air filter arrangement according to one of the preceding claims, characterized in that the first filter element (2) and / or the second filter element (3) is an activated carbon filter.

5. Air filter arrangement according to one of the preceding claims, characterized in that the air filter arrangement (1) comprises a third filter element (11) as a pre-filter, which is fixedly or detachably connected to the first and the second filter element (2, 3), preferably glued to them.

6. Air filter arrangement according to claim 5, characterized in that the third filter element (11) has a smooth surface (12).

7. Air filter arrangement according to claim 5 or 6, characterized in that the third filter element (11) is a foam filter or a fleece filter.

8. Air filter arrangement according to one of the preceding claims, characterized in that the respective filter elements (2, 3, 11) are present as filter layers (S1, S2, S3) arranged one above the other.

9. Air filter arrangement according to one of the preceding claims, characterized in that the air filter arrangement (1) forms an inlet side (E) and an outlet side (A), wherein a sealing element (15) is provided on the inlet side (E) and / or on the outlet side (A).

10. Air filter arrangement according to claim 9, characterized in that the sealing element (15) is designed in the form of a snap-in element for tool-free attachment to a fan housing (40).

11. Air filter arrangement according to one of the preceding claims, characterized in that the filter elements (2, 3, 11) which are firmly connected to one another together form an airtight casing (6).

12. Air filter arrangement according to one of the preceding claims, characterized in that the filter elements (2, 3, 11) which are firmly connected to one another together form a self-supporting air filter arrangement (1).

13. Fan unit (36, 39) with a fan housing (40) which forms an intake opening to which an air filter arrangement (1) according to one of the preceding claims is detachably fastened.

14. Fresh air system (33, 38) for a road construction machine (17, 27) in the form of a road paver (18) or a feeder vehicle (28) for a road paver (18), comprising at least one fan unit (36, 39) according to claim 13.

15. Method for replacing a plurality of used filter elements (2, 3, 11) of a fresh air system (33, 38) provided on a road finisher (18) or on a feeder vehicle (28), which are used as successively acting filter elements (2, 3, 11) for cleaning a bitumen-containing volume flow (V), characterized in thatthe plurality of used filter elements (2, 3, 11) are firmly connected to one another, removed together and replaced by a plurality of new, firmly connected filter elements (2, 3, 11).