Diffuser device for a device for determining particle emissions from brakes and device

Abstract

A diffuser device (1) for a device (3) for determining particle emissions from brakes is shown and described. The diffuser device (1) comprises a housing (5) extending along a flow direction (9), which defines an interior space (11) widening along the flow direction (9) and separates the interior space (11) from an environment (13) of the diffuser device (1) perpendicular to the flow direction (9). The housing also includes a subdivision unit (7) extending along the flow direction (9) that divides the interior space (11) into several sections perpendicular to the flow direction (9). A corresponding device (3) is also shown and described.

Description

[0001] The present invention relates to a diffuser device for a device for determining particle emissions from brakes and a corresponding device.

[0002] Diffuser devices for measuring brake particle emissions, and corresponding devices for measuring brake particle emissions, are known in the art. These devices for measuring brake particle emissions can also be referred to as brake test benches. Brake test benches with appropriate measuring technology are used to measure particle emissions, for example, from disc and / or drum brakes in cars, trucks, and / or rail vehicles. A brake can be driven by a test bench motor, and real brake load profiles can be simulated. Vehicle mass simulation can be achieved by combining a real flywheel with torque control of the test bench motor. Various speeds, as well as uphill and downhill driving, can also be simulated.The brake can be operated during the test run via a hydraulic actuator or, in the case of electromechanical brake systems, via a corresponding electrical control.

[0003] To measure particle emissions, the brake can be placed within a closed air duct. The area of ​​the brake test stand where the brake is positioned can also be referred to as the test specimen enclosure. An airflow, controlled with respect to volume flow, relative humidity, and temperature, is directed horizontally in the direction of travel and along a defined flow path over the brake within the test stand. This is intended to carry the emitted particles away from the brake and into a downstream measurement tunnel. Here, the number and size of the particles can be evaluated based on a partial volume flow. For example, the entire air duct, from particle generation to measurement, is operated under negative pressure compared to the test setup location, both to protect the operator and to increase measurement accuracy.The measuring tunnel, located downstream of the test specimen enclosure (viewed in the direction of flow), typically has a significantly smaller cross-section than the enclosure in which the brake under test is mounted. This ensures, firstly, a completely or fully developed, undisturbed flow profile within the measuring tunnel, even if turbulent flow conditions initially develop (viewed in the direction of flow), thus enabling isokinetic sampling across the entire cross-section of the measuring tunnel. Secondly, the time required for particle conglomerates to form can be reduced by increasing the flow velocity. Typically, the cross-section of the measuring section within the measuring tunnel (viewed in the direction of flow) and the cross-section of the air duct (viewed in the direction of flow) are of the same dimensions (viewed in the direction of flow) as the cross-section of the air duct (viewed in the direction of flow) upstream of the test specimen enclosure.Therefore, a rapid widening of the cross-section in a diffuser device or in a diffuser of the brake test stand, viewed in the direction of flow, is often necessary in front of the test specimen or in front of the test specimen enclosure.

[0004] In general, for diffuser devices and devices with such a diffuser device, it is desirable to optimize the airflow at the device, especially in a test specimen enclosure of the device downstream of the diffuser device in the direction of flow.

[0005] It is therefore the object of the present invention to optimize the airflow at the device, in particular in a test specimen enclosure of the device downstream of the diffuser device in the direction of flow, in a simple manner.

[0006] According to a first aspect of the invention, the aforementioned problem is solved by a diffuser device with the features of claim 1. The diffuser device is configured for a device for determining particle emissions from brakes. The diffuser device has a housing extending along a flow direction. The housing defines an interior space that widens along the flow direction. The housing separates the interior space from the surrounding area of ​​the diffuser device perpendicular to the flow direction. The diffuser device also has a subdivision unit extending along the flow direction. The subdivision unit divides the interior space into several sections perpendicular to the flow direction.The subdivision unit has several guide vanes extending along the flow direction, spaced apart perpendicular to the flow direction, and dividing the interior into several sections perpendicular to the flow direction. Each guide vane has a rectangular circumferential cross-sectional area extending along a plane perpendicular to the flow direction.

[0007] The diffuser assembly is configured for the device used to determine particle emissions from brakes. The diffuser assembly is configured for installation in the device and preferably includes fastening means for attaching it to a component of the device located upstream of the diffuser assembly (viewed from the flow direction), such as a straight pipe section of the device, and to a component of the device located downstream of the diffuser assembly (viewed from the flow direction), such as a test specimen housing of the device. The fastening means may include a first flange section located upstream of a flat section of the housing (viewed from the flow direction), and a second flange section located downstream of the flat section of the housing (viewed from the flow direction).Preferably, the planar section of the housing has an inner wall facing the interior.

[0008] The diffuser assembly comprises a housing extending along the direction of airflow. The direction of airflow is preferably defined by the direction along which an airflow is guided through the diffuser assembly incorporated into the device when measuring particle emissions from brakes. Because the housing extends along the direction of airflow, it limits the airflow at least along a portion of the path it travels when measuring particle emissions.In connection with the present invention, if a component of the diffuser device or apparatus extends along the direction of flow, it is preferably understood that the component extends from a corresponding first end to a corresponding second end, wherein the first end is arranged in a first plane extending perpendicular to the direction of flow and the second end is arranged in a second plane extending perpendicular to the direction of flow, and viewed along the direction of flow, the first plane is first passed by the airflow moving along the direction of flow, and subsequently the second plane is passed by the airflow.

[0009] The housing defines the interior space, which widens along the flow direction. By defining this interior space, the housing ensures that the flow cross-section widens along the flow direction. Preferably, the housing is configured such that the interior space widens continuously along the flow direction, which ensures particularly optimal airflow. Continuous widening of the interior space is preferably achieved by the housing having an inner wall facing the interior space, designed such that the area defined by the inner wall and lying in a plane perpendicular to the flow direction continuously increases in the flow direction.

[0010] The housing separates the interior from the surroundings of the diffuser device perpendicular to the flow direction. This separation, perpendicular to the flow direction, ensures that no particles from the interior can escape into the surroundings and vice versa. This allows for particularly precise measurement results with the brake particle test bench in which the diffuser device is installed.

[0011] The diffuser device also features a subdivision unit extending along the direction of airflow. Because the subdivision unit extends along the direction of airflow, it limits the airflow, at least along a portion of the path the airflow travels when measuring particle emissions. This can contribute to optimizing airflow at the device, particularly in a test specimen enclosure located downstream of the diffuser device along the direction of airflow.

[0012] The partition unit divides the interior space into several sections perpendicular to the flow direction. By dividing the interior space into several sections perpendicular to the flow direction, the partition unit ensures that the airflow passing through the diffuser is divided into multiple airflow segments. This allows for targeted control and optimization of the flow behavior of these airflow segments, significantly simplifying the optimization of airflow at the device, particularly in a test specimen enclosure located downstream of the diffuser along the flow direction. The partition unit can preferably also be referred to as a guide vane unit or guide vane insert.The subdivision unit preferably provides planar sections along which the airflow flows, thereby avoiding or at least significantly reducing turbulence in the airflow.

[0013] In summary, it can be stated that the airflow at the device, especially in a test specimen enclosure of the device located downstream of the diffuser device in the direction of flow, can be easily optimized using the diffuser device.

[0014] In one embodiment, the partition unit is designed such that the multiple sections of the interior widen along the direction of airflow. By designing the partition unit in such a way that the multiple sections of the interior widen along the direction of airflow, the partition unit ensures that each cross-section of each airflow segment widens along the direction of airflow. Preferably, the partition unit is configured such that the multiple sections of the interior widen continuously along the direction of airflow, which ensures particularly optimal airflow.A continuous widening of the several sections of the interior is preferably ensured by the fact that the subdivision unit has several walls which are designed in such a way that the surfaces defined by the walls and lying in a plane perpendicular to the flow direction continuously increase in the flow direction.

[0015] In one embodiment, the housing has first connecting means and the partition unit has second connecting means, wherein the housing and the partition unit can be detachably connected to one another by means of the first and second connecting means. Due to the detachable connection, the housing and the partition unit can be easily disassembled and, in the event of particle contamination, cleaned outside the device using suitable cleaning methods.

[0016] In one embodiment, the partition unit has a guide plate extending along the flow direction, which divides the interior into several sections perpendicular to the flow direction. Alternatively, the partition unit may simply have a guide plate extending along the flow direction, dividing the interior into several sections perpendicular to the flow direction. This provides a particularly material-friendly alternative.

[0017] According to the invention, the partition unit comprises several guide vanes extending along the flow direction, spaced apart from one another perpendicular to the flow direction, and dividing the interior space into several sections perpendicular to the flow direction. By having several guide vanes extending along the flow direction, spaced apart from one another perpendicular to the flow direction, and dividing the interior space into several sections perpendicular to the flow direction, backflow, i.e., the movement of air currents against the flow direction, can be prevented or at least the probability of its occurrence significantly reduced.Furthermore, by having the subdivision unit with several guide plates extending along the direction of flow, spaced apart perpendicular to the direction of flow and dividing the interior into several sections perpendicular to the direction of flow, large-scale vortices within the diffuser device can be prevented or at least the probability of their occurrence significantly reduced.

[0018] According to the invention, each guide plate of the guide plates has a rectangular circumferential cross-sectional area extending along a plane arranged perpendicular to the flow direction. Preferably, each guide plate of the guide plates has a square circumferential cross-sectional area extending along a plane arranged perpendicular to the flow direction. A rectangular, and in particular square, circumferential cross-sectional area can also be referred to as a rectangular, and in particular square, and hollow cross-sectional area. The rectangular, and in particular square, cross-sectional area of ​​each guide plate preferably circumferentially extends along a straight line along which the flow direction runs.Because each guide vane has a rectangular, in particular square, circumferential cross-sectional area extending along the plane perpendicular to the flow direction, at least some airflow segments can be guided by the diffuser device in such a way that, viewed along the flow direction, they also assume a rectangular, in particular square, circumferential shape, at least in part. A rectangular, in particular square, circumferential shape of at least some airflow segments has resulted in particularly optimal flow behavior in a test specimen enclosure located downstream of the diffuser device in the flow direction.Preferably, each guide plate of the guide plates has a rectangular, and in particular square, circumferential cross-sectional area along its entire extent in the direction of flow, extending along a corresponding plane arranged perpendicular to the direction of flow, thereby enabling particularly optimal flow behavior within the test specimen enclosure. The special case of the square circumferential cross-sectional area has resulted in particularly optimal flow conditions.

[0019] In one embodiment, the guide vanes are rectangular in shape and arranged in relation to each other such that a first straight line of two straight lines, which lie in a plane perpendicular to the flow direction and intersect in a straight line along which the flow direction runs, intersects two opposite corner points of each guide vane, and a second straight line of the two straight lines intersects the other two opposite corner points of each guide vane.By shaping the guide vanes into a rectangular form and arranging them such that a first line of two lines lying in a plane perpendicular to the flow direction and intersecting in a line along which the flow direction runs intersects two opposite corners of each guide vane, and a second line of the two lines intersects the other two opposite corners of each guide vane, a particularly optimal flow behavior is achieved. Preferably, each guide vane has a square circumferential cross-sectional area, and the two lines lying in the plane perpendicular to the flow direction and intersecting in the line along which the flow direction runs form a right angle between them. This results in a particularly optimal flow behavior.

[0020] In one embodiment, the diffuser device has a first rectifier unit extending perpendicular to the flow direction, which is arranged upstream of the dividing unit when viewed along the flow direction. Because the first rectifier unit extends perpendicular to the flow direction, it is ensured that the airflow strikes the first rectifier unit perpendicularly. Furthermore, because the first rectifier unit is arranged upstream of the dividing unit when viewed along the flow direction, the flow characteristics upstream of the dividing unit can be adjusted using the first rectifier unit.

[0021] Preferably, the first rectifier unit has a plurality of bores. These bores ensure that high-velocity areas within the airflow, guided along the flow direction, are decelerated and low-velocity areas are accelerated. For this purpose, the bores preferably have different diameters, which can be adapted to the geometry of the other sections of the device, and in particular the diffuser assembly. Furthermore, the bores ensure a pressure drop along the flow direction at the first rectifier unit when an airflow is present, thus preventing or at least reducing any secondary Dean vortices that may occur.The first rectifier unit preferably has a central section, preferably square, in which the plurality of bores are arranged. The bores are preferably arranged such that they are positioned along parallel rows and along columns perpendicular to the rows and parallel to each other. This arrangement of the bores has resulted in particularly optimal flow characteristics. The number of bores along each row is preferably identical, which allows for particularly uniform flow characteristics. Furthermore, the number of bores along each column is preferably identical, which also allows for particularly uniform flow characteristics. The first rectifier unit preferably has a boundary region that preferably extends around the preferably square central section.In the edge area, mounting holes are preferably provided, by means of which the first rectifier unit can be attached to a preferably circumferential flange section of the housing using connecting elements, such as preferably screws or rivets.

[0022] In one embodiment, the diffuser device includes a second rectifier unit extending perpendicular to the flow direction and located downstream of the dividing unit when viewed along the flow direction. The perpendicular orientation of the second rectifier unit ensures that the airflow strikes it perpendicularly. Furthermore, the downstream position of the second rectifier unit allows for adjustment of the flow characteristics downstream of the dividing unit.

[0023] Preferably, the second rectifier unit has a plurality of bores. The plurality of bores in the second rectifier unit ensures a pressure drop along the flow direction at the second rectifier unit when an airflow is present, thereby further homogenizing the flow characteristics. The diameters of the bores in the second rectifier unit are preferably identical, which ensures particularly uniform flow characteristics. The second rectifier unit preferably has a central section extending along a plane perpendicular to the flow direction. Because the central section extends along a plane perpendicular to the flow direction, it is ensured that the airflow strikes the central section perpendicularly.

[0024] Preferably, the second rectifier unit has a first edge section on a first side of the central section and a second edge section on a second side of the central section opposite the first side. The first edge section and the second edge section are preferably shaped to optimally match the shape of other components of the device. Preferably, the first edge section is connected to the central section and extends along a second plane on a side of the plane extending perpendicular to the flow direction that is arranged opposite to the flow direction. The second edge section is preferably connected to the central section and extends along a third plane on a side of the plane extending perpendicular to the flow direction that is arranged opposite to the flow direction.The second and / or third plane preferably intersect the plane extending perpendicular to the flow direction. The central section preferably has a first part of the plurality of bores, the first edge section preferably has a second part of the plurality of bores, and the second edge section preferably has a third part of the plurality of bores. The first edge section and / or the second edge section, as described, ensure that the airflow is optimally prepared for a cylindrically shaped component located downstream of the diffuser. The second rectifier unit thus configured can preferably also be described as having a top and bottom offset, with the first edge section forming a first offset region and the second edge section forming a second offset region.The bores in the central section, the bores in the first edge section, and the bores in the second edge section are preferably arranged such that they are positioned along parallel rows and along columns perpendicular to the rows and parallel to each other. This arrangement of the bores has resulted in particularly optimal flow characteristics.

[0025] Preferably, the second rectifier unit does not have an edge region with mounting holes, so that a particularly large area for the plurality of holes can be provided in the second rectifier unit compared to an embodiment in which such an edge region is provided. Preferably, projections are provided on a guide plate, each projection extending in the flow direction away from the corresponding guide plate and towards a distal end in which a hole is provided. Preferably, in an assembled state, each projection protrudes through a corresponding hole of the plurality of holes in the second rectifier unit, preferably the holes in the central section, such that the holes at the distal ends of the projections are exposed on a side of the second rectifier unit opposite the corresponding guide plate.To attach the second rectifier unit to the subdivision unit, the diffuser assembly preferably has fastening means, preferably designed as fastening clips. In the assembled state, a straight section of each fastening clip preferably extends through a corresponding bore in a corresponding distal end, so that the subdivision unit and the second rectifier unit are secured against relative movement to each other in the direction of flow. Preferably, a curved section of each fastening clip rests against two opposite sides of a corresponding distal end, so that the fastening clips are secured against slipping out of the corresponding bores in the distal ends perpendicular to the direction of flow.The mounting clips and the holes in the distal ends allow the subdivision unit and the second rectifier unit to be detachably connected. This detachable connection enables the subdivision unit and the second rectifier unit to be easily disassembled and, in the event of particle contamination, cleaned outside the device using appropriate cleaning methods.

[0026] According to a second aspect of the invention, the aforementioned problem is solved by a device with the features of claim 10. The device is designed for determining particle emissions from brakes. The device comprises a diffuser assembly according to the first aspect and a test specimen enclosure. The diffuser assembly is arranged upstream of the test specimen enclosure along the flow direction. By arranging the diffuser assembly upstream of the test specimen enclosure along the flow direction, the airflow at the test specimen enclosure can be optimally adjusted using the diffuser assembly. The features, technical effects, and / or advantages described in connection with the diffuser assembly according to the first aspect of the invention also apply, at least analogously, to the device according to the second aspect of the invention, so a corresponding repetition is omitted here.

[0027] The diffuser assembly and the device enable rapid cross-sectional expansion within the diffuser assembly, while simultaneously allowing the flow to follow the diffuser contour at the volume flows required for brake testing. Furthermore, the diffuser assembly and the device prevent or at least significantly reduce the likelihood of pronounced core flow, flow separation at the edges, and the formation of dead zones. Additionally, the diffuser assembly and the device prevent large-scale vortex formation and thus backflow within the test specimen enclosure. Finally, the diffuser assembly and the device ensure uniform flow around the brake under test, allowing particles to be removed from the brake over a large area rather than just at specific points.The reproducibility of the flow conditions within the test specimen enclosure, and thus the measurement accuracy, is increased. Measurement errors caused by particle deposits within the enclosure are reduced. Therefore, the diffuser and the device ensure high reproducibility of particle measurements and reduced particle deposition on the walls of the test specimen enclosure. Preferably, the device is configured such that the airflow upstream of the diffuser is operated under positive pressure, thereby reducing measurement errors due to background concentration.

[0028] Further features, advantages, and applications of the present invention will become apparent from the following description of the exemplary embodiments and the figures. All features described and / or illustrated, individually and in any combination, constitute the subject matter of the invention, irrespective of their composition in the individual claims or their cross-references. In the figures, the same reference numerals denote identical or similar objects. Fig. 1 and Fig. Figures 2 each show a schematic representation of an embodiment of a diffuser device according to the invention and Fig. Figure 3 shows a schematic representation of an embodiment of a device according to the invention with a [missing information] in the Fig. 1 and Fig. 2 diffuser device shown.

[0029] Fig. 1 and Fig. Figures 2 and 2 each show a schematic representation of an embodiment of a diffuser device 1 according to the invention. Fig. Figure 3 shows a schematic representation of an embodiment of a device 3 according to the invention with a [missing information] in the Fig. 1 and Fig. The diffuser assembly 1 is shown in Figure 2. The diffuser assembly 1 is configured for the device 3. The device 3 is configured to determine particle emissions from brakes and can also be referred to as a brake particle test bench or a section of a brake particle test bench. The airflow at the device 3 can be optimized using the diffuser assembly 1. First, the following is considered: Fig. 1 and Fig. 2 Diffuser device 1 shown and then onto the one in the Fig. Device 3 shown is included.

[0030] The diffuser assembly 1 has a housing 5 and a Fig. The housing 5 extends along a flow direction 9. The flow direction 9 is defined by the direction along which an airflow is guided through the diffuser device 1 integrated into the device 3 when measuring particle emissions from brakes. By extending along the flow direction 9, the housing 5 limits the airflow at least along a portion of the path traveled by the airflow when measuring particle emissions.In connection with the present invention, when a component of the diffuser device 1 or apparatus 3 extends along the flow direction 9, it is understood that the component extends from a corresponding first end to a corresponding second end, wherein the first end is arranged in a first plane extending perpendicular to the flow direction 9 and the second end is arranged in a second plane extending perpendicular to the flow direction 9, and viewed along the flow direction 9, the first plane is first passed by the airflow moving along the flow direction 9, and subsequently the second plane is passed by the airflow.

[0031] Furthermore, the housing 5 defines an interior space 11 that widens along the flow direction 9. By defining the interior space 11 that widens along the flow direction 9, the housing 5 ensures that the flow cross-section widens along the flow direction 9. In the Fig. 1 and Fig. In the embodiment of the diffuser device 1 shown in Figure 2, the housing 5 is configured such that the interior space 11 expands continuously along the flow direction 9, ensuring particularly optimal airflow. This continuous expansion of the interior space 11 is achieved by the housing 5 having an inner wall facing the interior space 11, which is designed such that the surface defined by the inner wall and lying in a plane perpendicular to the flow direction 9 continuously increases in the flow direction 9.

[0032] Furthermore, the housing 5 separates the interior 11 from the environment 13 of the diffuser device 1, viewed perpendicularly to the flow direction 9. By separating the interior 11 from the environment 13 of the diffuser device 1, the housing 5 ensures that no particles from the interior 11 enter the environment 13 in the area of ​​the housing 5, and conversely, that no particles from the environment 13 enter the interior 11, thus enabling particularly precise measurement results to be obtained with the brake particle test bench in which the diffuser device 1 is installed.

[0033] The subdivision unit 7 also extends along the flow direction 9. By extending along the flow direction 9, the subdivision unit 7 limits the airflow at least along a portion of the path the airflow travels when measuring particle emissions and can thus contribute to optimizing the airflow at the device 3. Furthermore, the subdivision unit 7 divides the interior space 11 perpendicular to the flow direction 9 into several sections, each section 15 of which is divided into Fig. 1 is at least partially visible. By dividing the interior space 11 into several sections perpendicular to the flow direction 9, the subdivision unit 7 ensures that the airflow through the diffuser device 1 is divided into several airflow sections when viewed perpendicular to the flow direction 9, thereby allowing the flow behavior of these airflow sections to be specifically influenced and optimized. The subdivision unit 7 is designed such that the several sections of the interior space 11 widen along the flow direction 9. By designing the subdivision unit 7 such that the several sections of the interior space 11 widen along the flow direction 9, the subdivision unit 7 ensures that each flow cross-section of each airflow section widens along the flow direction 9. In the section described in the Fig. 1 and Fig. In the embodiment of the diffuser device 1 shown in Figure 2, the partition unit 7 is configured such that the several sections of the interior 11 widen continuously along the flow direction 9, ensuring particularly optimal airflow. This continuous widening of the several sections of the interior 11 is achieved by the partition unit 7 having multiple walls designed such that the surfaces defined by the walls and lying in a plane perpendicular to the flow direction 9 continuously increase in the flow direction 9.

[0034] The subdivision unit 7 of the in the Fig. 1 and Fig. The embodiment of the diffuser device 1 shown in Figure 2 can also be referred to as a guide vane unit or guide vane insert. The subdivision unit 7 provides planar sections along which the airflow flows, thereby preventing or at least significantly reducing turbulence in the airflow. The subdivision unit 7 has several guide vanes extending along the flow direction 9, spaced apart from each other perpendicular to the flow direction 9, and dividing the interior space 11 into several sections perpendicular to the flow direction 9. Fig. In Figure 1, each guide vane 17 is shown at least section by section. Because the subdivision unit 7 has several guide vanes extending along the flow direction 9, spaced apart from each other perpendicular to the flow direction 9, and dividing the interior space 11 into several sections perpendicular to the flow direction 9, backflows, i.e., a movement of air currents against the flow direction 9, can be prevented or at least the probability of their occurrence significantly reduced. Furthermore, because the subdivision unit 7 has several guide vanes extending along the flow direction 9, spaced apart from each other perpendicular to the flow direction 9, and dividing the interior space 11 into several sections perpendicular to the flow direction 9, large-scale vortices within the diffuser device 1 can be prevented or at least the probability of their occurrence significantly reduced.

[0035] In the Fig. 1 and Fig. In the embodiment of the diffuser device 1 shown in Figure 2, four guide vanes are provided. However, the present invention is not limited to four guide vanes; rather, only one guide vane 17, two guide vanes, three guide vanes, or more than four guide vanes can also be provided. The subdivision unit 7 can therefore also have only one guide vane 17 extending along the flow direction 9, which divides the interior space 11 into several sections perpendicular to the flow direction 9. This provides a particularly material-friendly alternative. This single guide vane 17 can, for example, be one of the ones shown in Figure 2. Fig. Guide plate 17 shown in 1. Fig. The four guide vanes shown in Figure 1 divide the interior 11 perpendicular to the flow direction 9 into five sections, whereby with a correspondingly different number of guide vanes, a different number of sections of the several sections of the interior 11 may also be provided.

[0036] The guide vane 17, which is arranged radially inward with respect to a straight line along which the arrow symbolizing the flow direction 9 extends, can also be called the first guide vane. The guide vane 17 that is arranged radially around the first guide vane with respect to the straight line can also be called the second guide vane. The guide vane 17 that is arranged radially around the second guide vane with respect to the straight line can also be called the third guide vane. The guide vane 17 that is arranged radially around the third guide vane with respect to the straight line can also be called the fourth guide vane. The first guide vane defines a first section of the interior 11, wherein the first section is section 15 of the interior 11, which is arranged radially inward with respect to the straight line.The first guide plate, together with the second guide plate, defines a second section of the interior 11, wherein the second section is section 15 of the interior 11, which is arranged radially around the first section with respect to the line. The second guide plate, together with the third guide plate, defines a third section of the interior 11, wherein the third section is section 15 of the interior 11, which is arranged radially around the second section with respect to the line. The third guide plate, together with the fourth guide plate, defines a fourth section of the interior 11, wherein the fourth section is section 15 of the interior 11, which is arranged radially around the third section with respect to the line.The fourth guide plate, together with the housing 5, specifically with the inner wall of the housing 5 facing the interior 11, defines a fifth section of the interior 11, wherein the fifth section is the section 15 of the interior 11 which is arranged next around the fourth section in the radial direction with respect to the straight line.

[0037] Each guide vane 17 is shaped and arranged such that the distances between the guide vanes increase along the flow direction 9, causing each section 15 of the interior space 11 to widen continuously along the flow direction 9. The first guide vane is thus shaped and arranged such that the first section of the interior space 11 widens continuously along the flow direction 9. The first and second guide vanes are shaped and arranged such that the second section of the interior space 11 widens continuously along the flow direction 9. The second and third guide vanes are shaped and arranged such that the third section of the interior space 11 widens continuously along the flow direction 9. The third and fourth guide vanes are shaped and arranged such that the fourth section of the interior space 11 widens continuously along the flow direction 9.The fourth guide plate and the housing 5 are shaped and arranged such that the fifth section of the interior 11 widens continuously along the flow direction 9. Because each section 15 of the interior 11 widens continuously along the flow direction 9, a particularly advantageous flow profile is achieved.

[0038] Each guide vane 17 of the guide vanes has a rectangular, in particular square, circumferential cross-sectional area extending along a plane arranged perpendicular to the flow direction 9. A rectangular, in particular square, circumferential cross-sectional area can also be referred to as a rectangular, in particular square, and hollow cross-sectional area. The rectangular, in particular square, cross-sectional area of ​​each guide vane 17 circumferentially extends along the straight line along which the arrow symbolizing the flow direction 9 extends.Because each guide vane 17 of the guide vanes has a rectangular, in particular square, circumferential cross-sectional area extending along a plane arranged perpendicular to the flow direction 9, at least some airflow sections can be guided by the diffuser device 1 in such a way that, viewed along the flow direction 9, they also assume a rectangular, in particular square, circumferential shape at least partially. A rectangular, in particular square, circumferential shape of at least some airflow sections leads to a particularly optimal flow behavior in a test specimen enclosure 47 downstream of the diffuser device 1 in the flow direction 9 (see . Fig. 3) led. In the case of the Fig. 1 and Fig. In the embodiment of the diffuser device 1 shown in Figure 2, each guide plate 17 of the guide plates has a rectangular, in particular square, circumferential cross-sectional area along its entire extent along the flow direction 9. This area extends along a corresponding plane arranged perpendicular to the flow direction 9, thereby enabling particularly optimal flow behavior within the test specimen housing 47. The special case of the square circumferential cross-sectional area has resulted in particularly optimal flow conditions.

[0039] The guide vanes are rectangular in shape and arranged in such a way that a first line of two lines, lying in a plane perpendicular to the flow direction 9 and intersecting in the line along which the arrow symbolizing the flow direction 9 extends, intersects two opposite corner points of each guide vane 17, and a second line of the two lines intersects the other two opposite corner points of each guide vane 17. This results in particularly optimal flow characteristics. In the Fig. 1 and Fig. In the embodiment of the diffuser device 1 shown in Figure 2, each guide plate 17 has a square circumferential cross-sectional area, and the two straight lines lying in the plane perpendicular to the flow direction 9 and intersecting in the line along which the arrow symbolizing the flow direction 9 extends form a right angle between them. This results in particularly optimal flow characteristics.

[0040] The guide vanes are rectangularly shaped and arranged along the entire extent of each guide vane 17 in the direction of flow 9 such that a first line of two lines, lying in a plane perpendicular to the direction of flow 9 and intersecting in the line along which the arrow symbolizing the direction of flow 9 extends, intersects two opposite corners of each guide vane 17, and a second line of the two lines intersects the other two opposite corners of each guide vane 17. This results in particularly optimal flow behavior along the entire extent of the guide vanes in the direction of flow 9. In the Fig. 1 and Fig. In the embodiment of the diffuser device 1 shown in Figure 2, each guide plate 17 is square along its entire extent along the flow direction 9, and the two straight lines lying in the plane perpendicular to the flow direction 9 and intersecting in the line along which the arrow symbolizing the flow direction 9 extends form a right angle between them. This results in particularly optimal flow characteristics along the entire extent of the guide plate 17 along the flow direction 9.

[0041] Viewed perpendicular to the flow direction 9, the guide vanes are spaced apart from one another, forming the sections of the interior 11 between them. The guide vanes are spaced such that the distance between any two guide vanes adjacent perpendicular to the flow direction 9 corresponds to the distance between any other guide vanes adjacent perpendicular to the flow direction 9. The distances between guide vanes adjacent perpendicular to the flow direction 9 are therefore identical for all guide vanes. Because the distances between guide vanes adjacent perpendicular to the flow direction 9 are identical for all guide vanes, a particularly uniform flow behavior can be ensured, especially downstream of the diffuser device 1 in the flow direction 9.

[0042] Furthermore, the diffuser device 1 comprises a first rectifier unit 19, which in the illustrated embodiment is designed as a rectifier plate, and a second rectifier unit 21, which in the illustrated embodiment is also designed as a rectifier plate. The first rectifier unit 19 extends perpendicular to the flow direction 9 and is arranged upstream of the partition unit 7 when viewed along the flow direction 9. Because the first rectifier unit 19 extends perpendicular to the flow direction 9, it is ensured that the airflow strikes the first rectifier unit 19 perpendicularly. Because the first rectifier unit 19 is arranged upstream of the partition unit 7 when viewed along the flow direction 9, the flow characteristics upstream of the partition unit 7 can be adjusted using the first rectifier unit 19.

[0043] The second rectifier unit 21 also extends perpendicular to the flow direction 9 and is located downstream of the subdivision unit 7 when viewed along the flow direction 9. Because the second rectifier unit 21 extends perpendicularly to the flow direction 9, the airflow strikes the second rectifier unit 21 perpendicularly. Because the second rectifier unit 21 is located downstream of the subdivision unit 7 when viewed along the flow direction 9, the flow characteristics downstream of the subdivision unit 7 can be adjusted using the second rectifier unit 21. Because the first rectifier unit 19 and the second rectifier unit 21 are both designed as rectifier plates, the diffuser assembly 1 can be designed to be particularly compact when viewed along the flow direction 9.

[0044] The first rectifier unit 19 has a plurality of bores. These bores ensure that, within the airflow directed along the flow direction 9, areas of high velocity are decelerated and areas of low velocity are accelerated. For this purpose, the bores have different diameters, which can be adapted to the geometry of the other sections of the device 3 and, in particular, the diffuser assembly 1. Furthermore, the bores ensure a pressure drop along the flow direction 9 at the first rectifier unit 19 when an airflow is present, thus preventing or at least reducing any secondary Dean vortices that may occur. The first rectifier unit 19 has a square central section in which the plurality of bores are arranged.The bores are arranged such that they are positioned along parallel rows and along columns perpendicular to the rows and parallel to each other. This arrangement of the bores has resulted in particularly optimal flow characteristics. The number of bores along each row is identical, thus achieving a particularly uniform flow. Furthermore, the number of bores along each column is identical, again resulting in a particularly uniform flow. The first rectifier unit 19 has a rim region 23 that extends around the square central section. Mounting bores are provided in the rim region 23, by means of which the first rectifier unit 19 can be attached to a circumferential flange section 25 of the housing 5 using fasteners such as screws or rivets, as shown in [reference]. Fig. 2 is shown.

[0045] The second rectifier unit 21 also has a multitude of bores. The multitude of bores in the second rectifier unit 21 ensures a pressure drop along the flow direction 9 at the second rectifier unit 21 when an airflow is present, thus further homogenizing the flow behavior. The diameters of the bores in the second rectifier unit 21 are identical, which ensures particularly uniform flow behavior. The second rectifier unit 21 has a central section 27 that extends along a plane perpendicular to the flow direction 9. Because the central section 27 extends along the plane perpendicular to the flow direction 9, it is ensured that the airflow strikes the central section 27 perpendicularly.

[0046] The second rectifier unit 21 has a first edge section 29 on a first side of the central section 27 and a second edge section 31 on a second side of the central section 27 opposite the first side. The first edge section 29 and the second edge section 31 can be shaped to optimally match the shape of other components of the device 3. The first edge section 29 is connected to the central section 27 and extends along a second plane on a side opposite the flow direction 9 of the plane extending perpendicular to the flow direction 9. The second edge section 31 is connected to the central section 27 and extends along a third plane on a side opposite the flow direction 9 of the plane extending perpendicular to the flow direction 9.The second and third planes intersect the plane extending perpendicular to the flow direction 9. The central section 27 has a first part of the plurality of bores, the first edge section 29 has a second part of the plurality of bores, and the second edge section 31 has a third part of the plurality of bores. The first edge section 29 and the second edge section 31, configured as described, ensure that the airflow is optimally prepared for a cylindrically shaped component located downstream of the diffuser assembly 1. The second rectifier unit 21 can also be described as having a top and bottom offset, with the first edge section 29 forming a first offset section and the second edge section 31 forming a second offset section.The bores in the central section 27, the bores in the first edge section 29, and the bores in the second edge section 31 are each arranged such that they are positioned along parallel rows and along columns perpendicular to the rows and parallel to each other. This arrangement of the bores has resulted in particularly optimal flow characteristics.

[0047] The second rectifier unit 21 does not have an edge region with mounting holes, so that in the second rectifier unit 21 a particularly large area can be provided for the multitude of holes compared to an embodiment in which a corresponding edge region is provided. Instead, projections are provided on the fourth guide plate, each projection 33 of the projections extending in the flow direction 9 away from the fourth guide plate and towards a distal end 35 in which a hole is provided. In the Fig. In the assembled state shown in Figure 2, each projection 33 protrudes through a corresponding bore of the plurality of bores in the second rectifier unit 21, specifically the bores in the central section 27, such that the bores of the distal ends of the projections 33 are exposed on a side of the second rectifier unit 21 opposite the fourth guide plate. To attach the second rectifier unit 21 to the subdivision unit 7, the diffuser assembly 1 has fastening means which, when inserted into the Fig. 1 and Fig. In the embodiment shown in Figure 2, the components are designed as fastening clips. In the assembled state, a straight section of each fastening clip 37 extends through a corresponding bore in a corresponding distal end 35, thus securing the subdivision unit 7 and the second rectifier unit 21 against relative movement in the direction of flow 9. A curved section of each fastening clip 37 rests against two opposite sides of a corresponding distal end 35, thus securing the fastening clips against slipping out of the corresponding bores in the distal ends perpendicular to the direction of flow 9. The subdivision unit 7 and the second rectifier unit 21 can be detachably connected to one another by means of the fastening clips and the bores in the distal ends.Due to the detachable connection, the subdivision unit 7 and the second rectifier unit 21 can be easily disassembled and, in case of particle contamination, cleaned outside the device 3 using suitable cleaning methods.

[0048] The housing 5 has first connecting means and the subdivision unit 7 has second connecting means. The housing 5 and the subdivision unit 7 can be detachably connected to each other using the first and second connecting means. Due to the detachable connection, the housing 5 and the subdivision unit 7 can be easily disassembled and, in the event of particle contamination, cleaned outside the device 3 using suitable cleaning methods. Fig. Figure 1 shows two of the second connecting means, each of the two second connecting means being designed as a flange section 39. Each flange section 39 has a first section extending perpendicularly away from the fourth guide plate and a second section extending perpendicularly away from the first section and parallel to a section of the fourth guide plate. Each flange section 39 has a one-sided open elongated hole in its second section. The two in Fig. The flange sections shown in Figure 1 are spaced apart from each other when viewed in the flow direction 9. The first sections of the flange sections extend along the same plane, and the second sections of the flange sections extend along a second plane perpendicular to this plane. The elongated holes are thus located in the second plane.In the flange section 39 arranged opposite to the flow direction 9, the elongated hole is open opposite to the flow direction 9, so that the subdivision unit 7 can be moved into the housing 5 opposite to the flow direction 9, and a projection extending from the housing 5 in the direction of the straight line along which the arrow symbolizing the flow direction 9 runs can be moved over the open section of the elongated hole into the elongated hole, so that this projection together with the second section of the flange section 39, in the assembled state, creates a relative movement between the housing 5 and the subdivision unit 7 perpendicular to the flow direction 9, namely in . Fig. 1 up and down, prevented. In the flange section 39 arranged in the flow direction 9, the elongated hole is perpendicular to the flow direction 9, namely in Fig. 1 downwards, opened, so that the subdivision unit 7 can be moved into the housing 5 by tilting it relative to the housing 5 and moving it against the flow direction 9, and a projection extending from the housing 5 in the direction of the straight line along which the arrow symbolizing the flow direction 9 runs can be moved over the opened section of the elongated hole into the elongated hole, so that this projection together with the second section of the flange section 39 in the assembled state allows a relative movement between the housing 5 and the subdivision unit 7 along the flow direction 9, namely in Fig. 1 to the left and right, prevented. In Fig. Figure 1 shows only two flange sections, however, similar to the projections 33, two correspondingly designed flange sections are also provided on the opposite side of the subdivision unit 7, so that a mechanically robust but detachable connection between the housing 5 and the subdivision unit 7 can be provided.

[0049] As already described, the in Fig. 3 device shown 3 which is in the Fig. 1 and Fig. The device 3 is configured to determine particle emissions from brakes. In addition to the diffuser 1, the device 3 comprises a first straight pipe section 41, a pipe bend 43 with integrated guide vanes attached to the first straight pipe section 41, a second straight pipe section 45 attached to the pipe bend 43, the diffuser 1 attached to the second straight pipe section 45, a test specimen housing 47 attached to the diffuser 1, and a nozzle assembly 49 attached to the test specimen housing 47. Filtered air is guided to the diffuser 1 via the first straight pipe section 41, the pipe bend 43, and the second straight pipe section 45. In the diffuser 1, the cross-section widens along the flow direction 9 towards the test specimen housing 47.The diffuser device 1 is arranged in front of the test specimen housing 47 along the flow direction 9, so that the flow conditions in the test specimen housing 47 can be optimized with the aid of the diffuser device 1. A brake to be tested is mounted in the center of the test specimen housing 47 and connected via a rear-mounted and inlet. Fig. 3 shafts (not shown) are driven. In the nozzle assembly 49, the particles are collected, the air volume flow is accelerated and directed towards a measuring tunnel of the device 3.

[0050] During operation of the device 3, an uneven velocity profile distributed across the cross-section can occur due to components of the device 3 arranged upstream of the diffuser assembly 1 (viewed along the flow direction 9) and / or due to the cross-sectional expansion from the second straight pipe section 45 towards the test specimen housing 47. The bores of the first rectifier unit 19, in particular the bore distribution and / or bore sizes, are designed such that velocity increases are slowed down and slow velocity ranges are accelerated. Likewise, if secondary Dean vortices are generated in the pipe bend 43, these are reduced by a high pressure drop at the first rectifier unit 19. The partition unit 7 forces a widening of the flow profile, with the multiple baffle partitions preventing backflow and large-scale vortices within the diffuser assembly 1.The second rectifier unit 21 at the outlet of the diffuser device 1 ensures a further pressure drop, thereby homogenizing the flow behavior. To conform to the cylindrical shape of the test specimen housing 47, the second rectifier unit 21 is cranked at the top and bottom. This reduces dead water areas within the test specimen housing 47.

[0051] The diffuser device 1 achieves a homogeneous flow profile in the test specimen housing 47, both in magnitude and direction. This is demonstrated in particular on a vertical plane that is tangential to the brake disc and, when the flow approaches the brake disc, touches the point on the brake disc that can also be referred to as the stagnation point. The vertical plane is therefore located in front of a mounted brake disc when viewed along the flow direction 9. As already described, both the second rectifier unit 21 and the subdivision unit 7 can be easily disassembled and, in the event of particle contamination, cleaned outside the device 3 using suitable cleaning methods.

[0052] The diffuser device 1 represents a flow restriction, resulting in a pressure drop. The device 3 is therefore preferably configured such that, when testing a brake and with the corresponding airflow, the pressure upstream of the diffuser device 1 is higher than the pressure downstream of the diffuser device 1. Preferably, the device 3 is configured such that a slight negative pressure is maintained within the test specimen enclosure 47, i.e., the pressure in the test specimen enclosure 47 is lower than the ambient pressure 13. Despite the pressure drop in the diffuser device 1, the relative pressure at the pipework, i.e., at the first straight pipe section 41, the pipe bend 43, and the second straight pipe section 45, can still be positive, and any leaks in this area do not lead to an increase in the background concentration, since no outside air enters the system.Preferably, the device 3 is configured such that an overpressure is set within the first straight pipe section 41, the pipe bend 43 and the second straight pipe section 45, i.e., the pressure in the first straight pipe section 41, in the pipe bend 43 and in the second straight pipe section 45 is greater than the pressure in the environment 13, thereby reducing measurement errors due to background concentration.

[0053] Preferably, all internal components, in particular all components of the diffuser device 1, such as the housing 5, the subdivision unit 7, the first rectifier unit 19, the second rectifier unit 21, each projection 33, each mounting clamp 37, each flange section 39, as well as the first straight pipe section 41, the pipe bend 43, the second straight pipe section 45, the test specimen enclosure 47 and the nozzle device 49 are electrically connected to a grounded component of the device 3, such as a grounded pipe guide, in order to prevent electrostatic effects and associated particle deposition.

[0054] By adjusting the bore distribution and size within the first rectifier unit 19 and the second rectifier unit 21, customized flow profiles can be generated in the test specimen housing 47. For example, an increase in velocity is provided in edge regions to reduce potential particle deposits on the walls of the test specimen housing 47 and the nozzle assembly 49. The turbulence intensity can also be controlled in the same way.

[0055] In the illustrated embodiment of the diffuser device 1, the first rectifier unit 19 and the second rectifier unit 21 are each designed as a rectifier plate with a plurality of bores. Alternatively, the first rectifier unit 19 and / or the second rectifier unit 21 can each be designed as a flow straightener with a honeycomb structure or as a tube bundle. In the illustrated embodiment of the diffuser device 1, the subdivision unit 7 has several guide vanes extending along the flow direction 9. Instead of the selected form of the subdivision unit 7 as a guide vane insert, the subdivision unit 7 can also have airfoil profiles, porous structures, and / or packings.Alternatively, the subdivision unit 7 can also have a diffuser grid with multiple horizontal and vertical subdivisions extending from a first section of the diffuser device 1, at which a diffuser inlet is provided and from which the diffuser device 1 extends along the flow direction 9 towards a second section, to the second section at which a diffuser outlet is provided.

[0056] Particularly preferred are the internal components, in particular all components of the diffuser device 1, such as the housing 5, the subdivision unit 7, the first rectifier unit 19, the second rectifier unit 21, each projection 33, each mounting clamp 37, each flange section 39, as well as the first straight pipe section 41, the pipe bend 43, the second straight pipe section 45, the test specimen housing 47 and the nozzle device 49, designed to be mechanically robust, so that the internal components can perform a containment function, so that if, for example, the brake disc breaks during the testing of a brake, the walls of the device 3 do not allow parts of the brake disc to escape from the test stand.Preferably, the components of the diffuser device 1 and the components of the device 3 are designed such that, in the event of a brake disc breakage, they withstand the centrifugal force of the detached part of the brake disc, preventing this part from injuring nearby persons. Preferably, each component has an impact strength equal to or greater than a predetermined minimum impact strength. Preferably, the device 3 includes a particle generator or a device for introducing test dust. Preferably, the particle generator or the device for introducing test dust is attached to a component of the device 3, in particular to a component of the diffuser device 1. Thus, a defined quantity of particles or dust can be introduced into the device 3 and detected, and the device 3 can be evaluated or tested based on this detection.

[0057] It should be further noted that "having" does not exclude any other elements or steps, and "a" or "an" does not exclude a plurality. It should also be noted that features described with reference to one of the above embodiments may also be used in combination with other features of other embodiments described above. Reference numerals in the claims are not to be considered as a limitation. Reference sign 1 Diffuser device 3 Device 5 cases 7 Subdivision unit 9 Flow direction 11 Interior 13 Environment Section 15 of the interior 17 Guide plate 19 first rectifier unit 21 second rectifier unit 23 Edge area 25 Flange section 27 Central section 29 first marginal section 31 second marginal section 33 lead 35 distal end of the projection 37 Mounting bracket 39 Flange section 41 first straight pipe section 43 pipe bends 45 second straight pipe section 47 Examinee enclosure 49 Nozzle assembly

Claims

[1] Diffuser device (1) for a device (3) for detecting particle emissions from brakes, wherein the diffuser device (1) is a housing (5) extending along a flow direction (9) which defines an interior space (11) widening along the flow direction (9) and separates the interior space (11) from an environment (13) of the diffuser device (1) perpendicular to the flow direction (9), a subdivision unit (7) extending along the direction of flow (9), which divides the interior space (11) into several sections perpendicular to the direction of flow (9), wherein the subdivision unit (7) has several guide plates extending along the direction of flow (9), which are spaced apart from each other perpendicular to the direction of flow (9) and which divide the interior space (11) perpendicular to the direction of flow (9) into the several sections, and wherein each guide plate (17) of the guide plates has a rectangular circumferential cross-sectional area extending along a plane arranged perpendicular to the flow direction (9). [2] Diffuser device (1) according to the preceding claim, wherein the subdivision unit (7) is designed such that the multiple sections of the interior (11) widen along the flow direction (9). [3] Diffuser device (1) according to one of the preceding claims, wherein the housing (5) has first connecting means and the subdivision unit (7) has second connecting means, wherein the housing (5) and the subdivision unit (7) can be detachably connected to each other by means of the first connecting means and second connecting means. [4] Diffuser device (1) according to one of the preceding claims, wherein the subdivision unit (7) has a guide plate (17) extending along the flow direction (9) which divides the interior space (11) perpendicular to the flow direction (9) into the several sections. [5] Diffuser device (1) according to one of the preceding claims, wherein the guide plates are rectangular in shape and arranged relative to each other such that a first straight line of two straight lines, which lie in a plane perpendicular to the flow direction (9) and intersect in a straight line along which the flow direction (9) runs, intersects two opposite corner points of each guide plate (17) and a second straight line of the two straight lines intersects the other two opposite corner points of each guide plate (17). [6] Diffuser device (1) according to one of the preceding claims, comprising a first rectifier unit (19) extending perpendicular to the flow direction (9) and arranged upstream of the subdivision unit (7) as seen along the flow direction (9). [7] Diffuser device (1) according to one of the preceding claims, comprising a second rectifier unit (21) extending perpendicular to the flow direction (9) and arranged downstream of the subdivision unit (7) as seen along the flow direction (9). [8] Device (3) for determining particle emissions from brakes, wherein the device (3) comprises a diffuser device (1) according to one of the preceding claims and a test specimen enclosure (47), wherein the diffuser device (1) is arranged in front of the test specimen enclosure (47) as seen along the flow direction (9).

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