CLEANING DEVICE AND USE OF A FLOW DIVERSION ELEMENT

Description

[0001] The invention relates to a cleaning device comprising at least one noise source and an air guidance device with at least one flow deflection element, wherein the at least one flow deflection element has a first tube arm with a first opening and a second tube arm with a second opening, and wherein the second tube arm is oriented transversely to the first tube arm.

[0002] DE 10 2018 108 559 A1 discloses a cleaning device comprising at least one noise source, a sound-affected air guide, and a noise reduction device integrated into the air guide. The noise reduction device comprises a combination of at least one perforated plate resonator and a flow deflection element.

[0003] DE 20 2011 108 261 U1 discloses a vacuum cleaner main body with a fan insert capable of generating an airflow and with an air discharge circuit arranged downstream of the fan assembly, defining a variable flow cross-section along its path to the outlet area. At least one intermediate bend is provided between the fan assembly and the outlet area, into which a section of the discharge circuit connects. In this section of the discharge circuit, a homogenizing agent is arranged downstream of the at least one bend, which ensures the reduction of airflow turbulence.

[0004] WO 2011 / 051002 A1 reveals a radial fan.

[0005] WO 2018 / 068850 A1 discloses a cleaning device comprising at least one noise source and an air guidance device with at least one flow deflection element, wherein the at least one flow deflection element has a first arm with a first inlet pipe and a second arm with an outlet pipe, the outlet pipe is oriented transversely to the inlet pipe, the inlet pipe has an inlet with an extent in a first depth direction and in a first width direction, the outlet pipe has an outlet with a depth in a second depth direction and a width in a second width direction, the first depth direction and the second depth direction are oriented parallel to each other, and the first width direction and the second width direction are oriented transversely to each other, wherein the width in the second width direction is at least 1.2 times the depth in the second depth direction.

[0006] From WO 2015 / 043641 A1, a suction device is known, comprising a blower device for generating a suction airflow and an air guide device, which has at least one flow deflection element with an inlet pipe and an outlet pipe, wherein the outlet pipe is oriented transversely to the inlet pipe. A sound reflector device is arranged at a transition area between the inlet pipe and the outlet pipe, at which sound is reflected and / or absorbed.

[0007] From WO 2016 / 112959 a suction device is known, comprising a suction unit, a dirt collection container, a filter device and a cleaning device for the filter device, wherein the cleaning device forms a noise source for noise emissions in a frequency range below 2000 Hz, and at least one perforated plate resonator is assigned to the cleaning device.

[0008] The invention is based on the objective of providing a cleaning device of the type mentioned above in which effective sound attenuation of sound emitted by the at least one noise source is provided with high flow efficiency for fluid guidance.

[0009] This problem is solved in the cleaning device of the type described above by the fact that the ratio of a first width of the first opening to a second width of the second opening is greater than 1.

[0010] It has been shown that this results in a relatively large overall transmission loss for sound pressure (integrated over all frequencies).

[0011] This is due to the emergence of evanescent modes, i.e., modes that cannot propagate, resulting in an increased transmission loss.

[0012] In this context, explicit and full reference is made to the unpublished dissertation "Acoustic and aerodynamic phenomena in duct bends" by Dominik Scholl, Institute for Acoustics and Building Physics of the University of Stuttgart, 2021.

[0013] In order to achieve relatively large (total) transmission losses with respect to sound pressure, it is advantageous if the ratio is greater than or equal to 1.2 and in particular greater than or equal to 1.4 and in particular greater than or equal to 1.5.

[0014] It has been shown that the influence on the flow rate can be kept relatively low if the ratio is less than or equal to 3, and in particular less than or equal to 2.8, and in particular less than or equal to 2.6, and in particular less than or equal to 2.5.

[0015] In an advantageous embodiment, in which an effective overall transmission loss with respect to sound pressure is achieved and good flow efficiency is achieved, the ratio is between (inclusive) 1.5 and (inclusive) 2.

[0016] It is specifically designed that the first opening is an inlet opening for sound and the second opening is an outlet opening for sound, and that during operation of the cleaning device, sound propagation occurs from the first opening to the second opening. Sound is, in effect, coupled in at the first opening and (attenuated) coupled out at the second opening. With regard to sound propagation, the first opening is then closest to the at least one noise source. In principle, it is possible for air to flow from the first opening to the second opening. However, it is also possible for air to flow in the opposite direction, from the second opening to the first opening. The influence of the airflow direction in the at least one flow deflection element on sound propagation is relatively small.

[0017] It is advantageous if at least one of the following is provided: The first pipe arm extends in a first direction of extension, which is normal to the first opening; the second pipe arm extends in a second direction of extension, which is normal to the second opening; the first direction of extension and the second direction of extension are transverse and, in particular, perpendicular to each other; a first lateral direction, in which the first width is measured, is transverse and, in particular, perpendicular to the first direction of extension; a second lateral direction, in which the second width is measured, is transverse and, in particular, perpendicular to the second direction of extension; the first lateral direction and the second direction of extension are at least approximately parallel to each other; the second lateral direction and the first direction of extension are at least approximately parallel to each other;The first opening has an extension in a first depth direction, which is perpendicular to the first latitude direction and transverse and, in particular, perpendicular to the second latitude direction; the second opening has an extension in a second depth direction, which is oriented perpendicular to the second latitude direction and transverse and, in particular, perpendicular to the first latitude direction; the first latitude direction and the second latitude direction lie in a plane to which the first depth direction and the second depth direction are oriented transversely and, in particular, perpendicularly.

[0018] The flow deflection element is designed as a sound angle, with the first and second pipe arms being perpendicular to each other. Due to these geometric relationships, the first and second openings are oriented transversely to each other.

[0019] The basic principle is that the first width of the first opening refers to a rectangular envelope with sides extending in a first width direction and in a depth direction perpendicular to that first width direction, and that the second width of the second opening refers to a rectangular envelope with sides extending in a second width direction and in a second depth direction perpendicular to that second width direction. The first and second openings do not necessarily have to be rectangular or square, respectively. The first and second widths are then defined in relation to the rectangular envelope.

[0020] For the same reason, it is advantageous if the first opening has a rectangular envelope which has sides extending in a first latitude direction and in a first depth direction perpendicular to the first latitude direction, and the second opening has a rectangular envelope which has sides extending in a second latitude direction and in a second depth direction perpendicular to the second latitude direction.

[0021] It is advantageous if at least one of the following is provided: The first pipe arm has a uniform cross-section extending from the first opening to a transition area to the second pipe arm; the second pipe arm has a uniform cross-section extending from the second opening to a transition area to the first pipe arm.

[0022] This makes it easy to manufacture and dimension the corresponding flow deflection element.

[0023] In a structurally advantageous simple embodiment, at least one of the following is provided: The first opening has a rectangular or square cross-section; the first pipe arm has a rectangular or square inner cross-section; the second opening has a rectangular or square cross-section; the second pipe arm has a rectangular or square inner cross-section.

[0024] In an advantageous embodiment, the at least one flow deflection element is flat. This provides at least one of the following: The second width of the second opening is at least 1.2 times greater than a second depth of the second opening in a second depth direction perpendicular to a second latitude direction in which the second width is measured, and is in particular at least 1.9 times greater; the first width of the first opening is at least 1.2 times greater than a first depth of the first opening in a first depth direction perpendicular to a first latitude direction in which the first width is measured, and is in particular at least 1.9 times greater.

[0025] This results in high flow efficiency and also broadband noise attenuation. Reference is made in this context to WO 2018 / 068850 A1.

[0026] In an advantageous embodiment, the first and second pipe arms share a common edge at an outer corner, extending in a depth direction transverse to a first width direction and transverse to a second width direction. This allows for effective sound attenuation at the transition between the first and second pipe arms. In particular, this creates a type of sound reflection, generating transverse modes. Effective sound pressure reduction is achieved.

[0027] In an advantageous embodiment, a transition area between the first pipe arm and the second pipe arm has a curved wall, in particular with at least one of the following: The curved wall lies opposite a common edge of the first pipe arm and the second pipe arm; an inner radius on the curved wall is larger than half the hydraulic diameter of the first pipe arm.

[0028] This results in high flow efficiency. Pressure losses during the flow through the at least one flow deflection element can be kept low.

[0029] In particular, at least one of the following is provided for: The noise source is a blower or a pump; the air guidance device is a guidance device for process air or cooling air; the air guidance device is a guidance device for cleaning air and especially blowing air; the air guidance device is a guidance device for drying air.

[0030] In particular, the air guidance device is connected to the at least one noise source as a blower, and the blower, in addition to its design as a noise source, is also a source, in particular, for a blowing airflow or a suction airflow.

[0031] The cleaning device advantageously includes an application tool for the surface to be cleaned. This application tool can be a nozzle (such as a pressure nozzle or suction nozzle), like a suction nozzle on a vacuum cleaner or a pressure nozzle on a leaf blower. It can be a roller, which is, for example, vacuumed, or a squeegee on a scrubbing machine.

[0032] In one embodiment, at least one application tool is coupled to the air supply system. With a corresponding nozzle, this is directly coupled to the air supply system. For example, in wet floor cleaning, a cleaning roller may be designed to be suctioned and thus coupled to the air supply system.

[0033] The cleaning device can be designed as a portable cleaning unit or as a stationary cleaning unit such as a washing portal. The cleaning device can be self-propelled and self-steering, or it can be a vehicle. It can be handheld and / or hand-guided.

[0034] For example, the cleaning device is designed as a high-pressure cleaner, sweeper, floor cleaning machine, scrubber, vacuum cleaner, window vacuum cleaner, handheld and / or hand-guided wet floor cleaning machine, leaf blower, steamer, or washing portal.

[0035] With high flow efficiency, effective noise reduction is achieved if, during operation of the cleaning device, sound propagation occurs from the first pipe arm to the second pipe arm and a mode filter device for transverse modes of sound propagation is arranged on the at least one flow deflection element, with at least one mode filter positioned on the second pipe arm.

[0036] The flow deflection element guides the flow, and in particular directs the airflow. Furthermore, sound propagation occurs within the at least one flow deflection element.

[0037] In principle, sound can propagate in the at least one flow deflection element as a fundamental mode, as a transverse mode of the first order, and as transverse modes of higher order.

[0038] Transverse modes are generated at a transition zone between the first pipe arm and the second pipe arm, which then propagate into the second pipe arm.

[0039] It has been shown that if a mode filter for transverse modes is arranged on the second pipe arm, transverse modes can be suppressed accordingly, resulting in effective sound attenuation.

[0040] In this context, reference is made to the unpublished dissertation "Acoustic and aerodynamic phenomena in duct bends" by Dominik Scholl, Institute of Acoustics and Building Physics, University of Stuttgart, 2021. The dissertation is explicitly and fully referenced.

[0041] In particular, the at least one flow deflection element has a sound deflection zone for sound propagation from the first pipe arm to the second pipe arm, and with respect to sound propagation, at least one mode filter for transverse modes is located downstream of the sound deflection zone. Transverse modes are generated at the sound deflection zone, which can be effectively dampened by the corresponding mode filter on the second pipe arm.

[0042] It is advantageous if at least one of the following is provided: The at least one mode filter, which is positioned on the second pipe arm, is spaced away from a sound deflection area; the at least one mode filter, which is positioned on the second pipe arm, is spaced away from the first pipe arm;The spacing of the at least one mode filter, which is arranged on the second pipe arm, is at least 0.1 times and in particular at least 0.15 times (and preferably at least 0.2 times, and preferably at least 0.3 times, and preferably at least 0.4 times, and preferably at least 0.5 times, and preferably at least 0.6 times, and preferably at least 0.7 times, and preferably at least 0.8 times) of a first width of the first pipe arm in a first lateral direction or of a second width of the second pipe arm in a second lateral direction, wherein the spacing is parallel to a first lateral direction and is referenced to a side of the first pipe arm which lies at an inner corner region of the at least one flow deflection element.

[0043] It has been shown that this allows for effective mode filtering for transverse modes with effective sound attenuation.

[0044] The mode filtering device may also include at least one mode filter for transverse modes, which is arranged on the first pipe arm. A mode filter for transverse modes, arranged on the second pipe arm, is more effective due to the generation of transverse modes during sound deflection.

[0045] It is particularly advantageous if, during sound propagation through the at least one flow deflection element in the operation of the cleaning device, transverse modes with propagation in a first lateral direction and a second lateral direction, as well as transverse modes with propagation in a first depth direction and a second depth direction, can fundamentally form. Transverse modes generally have a cutoff frequency. Below this cutoff frequency, these modes are evanescent and cannot propagate (i.e., their frequency decays exponentially).

[0046] It is specifically designed that at least one mode filter is installed on the second pipe arm to filter transverse modes in the second lateral direction. These are the first transverse mode, the second transverse mode, and so on. Transverse modes in the second depth direction are also present, but they do not play a significant role in sound attenuation.

[0047] A mode filter of the mode filtering device for transverse modes is or includes at least one of the following: an absorption silencer; a chamber silencer; a perforated device positioned in an interior space of the at least one flow deflection element.

[0048] The absorption silencer, chamber silencer, or perforated plate is typically located on the second pipe arm. It is also possible to arrange a corresponding mode filter on the first pipe arm. In principle, it is also possible to use several types of these mode filters simultaneously.

[0049] In an advantageous embodiment, the absorption silencer incorporates sound absorption material, which is arranged in particular as an absorption layer. This allows for effective sound attenuation of transverse modes.

[0050] It is specifically designed that the absorption material is flush with an inner surface of the at least one flow deflection element or recessed relative to an inner surface of the at least one flow deflection element. If recessed, the absorption silencer can also be designed as a chamber silencer (with appropriate dimensions). This allows for effective mode filtering of transverse modes.

[0051] In particular, the absorption silencer has at least one of the following parameters: The thickness of the absorption material is at least 0.1 times, and in particular at least 0.15 times, and in particular at least 0.2 times, and in particular at least 0.25 times, the width of the first or second pipe arm; the length of the absorption silencer parallel to a direction of extension of the pipe arm on which the absorption silencer is arranged is at least 1.5 times, and in particular at least 2 times, and in particular at least 2.3 times, the width of the first or second pipe arm; the distance of the absorption silencer, which is arranged on the second pipe arm, is at least 0.1 times the width of the first or second pipe arm.

[0052] If at least one of these parameters is met, effective mode filtering for transverse modes results, and consequently a high transmission loss for sound pressure, i.e., effective sound attenuation.

[0053] In one embodiment, the chamber silencer has a chamber that forms a cross-sectional expansion on the pipe element to which the chamber silencer is attached. With appropriate dimensioning, effective mode filtering can be achieved.

[0054] In particular, the chamber silencer has at least one of the following parameters: The width of the chamber is at least twice the width of the first or second pipe arm; the length of the chamber silencer parallel to a direction of extension of the pipe arm on which the chamber silencer is arranged is at least 1.2 times the width of the first and second pipe arms; the distance of the chamber silencer, which is arranged on the second pipe arm, to the first pipe arm is at least 0.1 times, and in particular at least 0.15 times, and in particular at least 0.5 times, the width of the first or second pipe arm.

[0055] If at least one of these parameters is present, effective mode filtering results.

[0056] It is advantageous if at least one of the following is present in the perforated device: Openings in the perforated device have an opening width of less than or equal to 1 mm; the opening density is greater than or equal to 10 openings per square centimeter; the wall thickness of the perforated device transverse to a width direction of the pipe arm on which the perforated device is arranged is at least 1 mm.

[0057] A mode filter for transverse modes can also be implemented by appropriately designing the perforated device. In particular, the perforated device is positioned within the flow path of the corresponding pipe arm.

[0058] It is advantageous if at least one of the following is provided: The perforated device is or comprises one or more plates with openings; the perforated device comprises one or more open-pore structures; an open-pore structure is formed as a block; an open-pore structure is a foam structure and in particular an absorber foam structure and / or a fibrous material structure such as a nonwoven structure.

[0059] This allows for the simple implementation of a mode filter. For example, the perforated device comprises one or more plates that are perforated (provided with openings). Specifically, the openings are open along the width of the respective pipe arm on which the perforated device is mounted. For instance, a plate is positioned centrally within the pipe arm and aligned parallel to the pipe arm's length. Alternatively, multiple plates, spaced apart from one another, can be positioned within the interior. In this case, fluid flow is possible in the space between the plates.

[0060] The perforated device can also incorporate one or more open-pore structures to create a suitable mode filter. In particular, an open-pore structure is formed as a block and then in a plate-like form. An open-pore structure can be, for example, a foam structure, especially an absorber foam structure, or a fiber material structure. Using an absorber foam structure also allows for sound absorption at the perforated device. The fiber material structure can be, for example, a non-woven structure. In principle, a woven or knitted structure is also possible.

[0061] It may be designed so that the absorption silencer, chamber silencer, or perforated device is only designed to attenuate transverse modes in a width direction. In particular, it then lacks any design for attenuating transverse modes in the depth direction, which play only a minor role.

[0062] A significant reduction in noise is achieved when the first pipe arm and the second pipe arm share a common edge at an external corner.

[0063] A high flow efficiency is achieved if an installation wall is arranged in an interior space of the at least one flow deflection element, which covers the edge in the interior space, the installation wall faces a flow area in the interior space, and the installation wall is designed to be flow-guiding and sound-permeable.

[0064] The collision of the first and second pipe arms with the edge at the outer corner area results in effective noise reduction through corresponding sound damping.

[0065] By designing the mounting wall to be sound-permeable, the effective noise reduction achieved through the edge design is maintained. The flow-guiding function of the mounting wall results in high flow efficiency, as the fluid flow, which is guided through the at least one flow deflection element, does not have to flow past the edge, but is instead directed by the mounting wall in front of it.

[0066] According to the invention, a flow deflection element is provided which achieves effective sound attenuation with high flow efficiency. In this context, reference is made to the unpublished dissertation "Acoustic and aerodynamic phenomena in duct bends" by Dominik Scholl, Institute for Acoustics and Building Physics, University of Stuttgart, 2021.

[0067] It is advantageous if the installation wall rests against the inside of the first pipe arm and the inside of the second pipe arm. This results in effective flow guidance.

[0068] In one embodiment, at least one of the following is provided: The transition of the installation wall to the inside of the first pipe arm and the second pipe arm is smooth and, in particular, edgeless; the installation wall is curved towards the flow area and, in particular, is concavely curved.

[0069] This results in an effective flow guidance function with high flow efficiency. In particular, turbulence in the fluid flow at the transition from the installation wall to the inner side of the pipe arm can be kept to a minimum.

[0070] It is advantageous if at least one of the following is present: The installation wall is or comprises a perforated element, and in particular a perforated surface element or block element; the installation wall is or comprises a porous foam element or fiber material element; the opening width of openings in the installation wall towards the edge is at least λ / 50, where λ is an upper sound wavelength relevant for noise emission; the opening width of openings in the installation wall towards the edge is at least 1 mm.

[0071] The installation wall includes openings that are permeable to sound. The installation wall can be a perforated element, and in particular a flat element such as a sheet metal element or a block element. It is also possible that the installation wall is or comprises a porous foam element or fiber material element, and, for example, fills the entire space from the airflow area to the edge.

[0072] It is advantageous if the opening width of any openings (e.g., perforations or pores) in the installation wall is at least λ / 50 for a sound wavelength relevant to noise emission. This allows for sound transmission towards the edge. In particular, the opening width should be at least 1 mm.

[0073] The edge is, in particular, a connecting line between opposite outer corners of the at least one flow deflection element. It is advantageous if the first pipe arm and the second pipe arm lie at an angle between 70° and 110°, and especially at an angle between 80° and 100°, at the edge.

[0074] In an advantageous embodiment, the first pipe arm and the second pipe arm meet at right angles to each other.

[0075] In a structurally simple embodiment, the installation wall has a constant curvature, meaning that, particularly towards the flow path, it has the shape of a cylindrical shell section. This results in simple manufacturability with high flow efficiency.

[0076] It is advantageous if the center of curvature of the mounting wall lies between the first and second pipe arms. This results in a structurally simple design.

[0077] It has proven advantageous if a transition area from the first pipe arm to the second pipe arm has a curved wall at an inside corner area opposite the outside corner area, leading to the interior of at least one flow deflection element. This results in high flow efficiency.

[0078] In particular, the curved wall faces the installation wall, and a flow-through zone lies between the curved wall and the installation wall within the interior. The installation wall and the curved wall are flow-conducting for the flow passing through the flow-through zone.

[0079] In an advantageous embodiment, the curved wall has a constant curvature.

[0080] It has proven advantageous for high flow efficiency if a circle of curvature for the curved wall has an inner radius that is larger than half the hydraulic diameter of a first opening of the first pipe arm.

[0081] In a structurally advantageous embodiment, the curved wall and the installation wall are aligned parallel and, in particular, have a common center point.

[0082] In particular, the installation wall is oriented parallel to a first depth direction and / or parallel to a second depth direction and has a uniform height in the first and / or second depth direction, respectively. This results in high flow efficiency.

[0083] According to the invention, a flow deflection element is provided which has a first pipe arm with a first opening and a second pipe arm with a second opening, wherein the second pipe arm is oriented transversely to the first pipe arm and the ratio of the first width of the first opening to the second width of the second opening is greater than 1, which according to the invention is used in a cleaning device with a noise source.

[0084] This use offers the advantages already explained in connection with the cleaning device according to the invention.

[0085] Further advantageous embodiments have also already been explained in connection with the cleaning device according to the invention.

[0086] In particular, during operation of the cleaning device, the flow deflection element is permeated with air. The flow deflection element redirects the airflow and also ensures a corresponding redirection of sound propagation.

[0087] The following description of preferred embodiments, in conjunction with the drawings, serves to further explain the invention. The drawings show: Figure 1 shows an embodiment of a flow deflection element in perspective view; Figure 2 shows a schematic and exemplary flow conditions for a flow deflection element according to Figure 1 in sectional view; Figure 3 also schematically shows flow conditions at a flow deflection element according to Figure 1in perspective view; Figure 4 schematically shows fundamental modes (1) which occur in a pipe arm at different frequencies f1, f2, f3 during sound propagation in a pipe arm of the flow deflection element according to Figure 1can form first transverse modes (2) and second transverse modes (3) in a lateral direction at the corresponding different frequencies (evanescent transverse modes that cannot propagate in the tube arm at the corresponding frequency are marked with a cross); Figure 5 a diagram of the total transmission loss for a flow deflection element as a function of the ratio of a first width to a second width of the flow deflection element; Figures 6(a) to (d) different geometric configurations of the flow deflection element; Figure 7(a) schematically a cross-section of an embodiment of a flow deflection element which is provided with a first embodiment of a mode filter; Figure 7(b) a similar view to Figure 6(a) with a second embodiment of a mode filter; Figure 7(c) a similar view to Figure 6(a)with a third embodiment of a mode filter; Figure 8 a diagram of a transmission loss as a function of a normalized frequency for a flow deflection element according to Figure 7(a)Figure 9(a) schematically shows an embodiment of a flow deflection element with an edge; Figure 9(b) schematically shows an embodiment of a flow deflection element without an edge; Figure 10 schematically shows an embodiment of a flow deflection element according to the invention with an insert; Figure 11 a schematic representation of another embodiment of a flow deflection element according to the invention; Figures 12 to 15 schematically show an embodiment of a suction device with different flow deflection elements according to the invention; Figures 16 to 19 schematically show an embodiment of a high-pressure cleaning device with different flow deflection elements according to the invention; Figures 20 to 23 schematically show an embodiment of a hand-held (wet) floor cleaning device with different embodiments of a flow deflection element according to the invention;Figures 24 to 27 schematically show an embodiment of a window vacuum cleaner with different embodiments of flow deflection elements according to the invention; Figures 28 to 31 show an embodiment of a leaf blower with different embodiments of flow deflection elements according to the invention; Figures 32 to 35 schematically show an embodiment of a ride-on sweeper with different embodiments of flow deflection elements according to the invention; Figures 36 to 39 schematically show an embodiment of a walk-behind scrubber with different embodiments of flow deflection elements according to the invention; Figures 40 to 43 schematically show an embodiment of a municipal vehicle with different embodiments of flow deflection elements according to the invention; and Figures 44 to 47 show an embodiment of a car wash portal with different embodiments of flow deflection elements according to the invention.

[0088] A cleaning device according to the invention, of which exemplary embodiments are described in the Figures 12 to 47 The system shown and explained in more detail below includes (at least) one noise source. The noise source is a sound generator.

[0089] An example of such a noise source is a blower with at least one rotating impeller. Depending on the application, the blower serves, for example, to generate a suction flow or a blowing flow. The cleaning device includes an air guide to direct the airflow. The air guide is coupled to the noise source, and sound can propagate within the air guide.

[0090] The air guidance system has (at least) one flow deflection element connected to it or includes such an element within it.

[0091] An embodiment of such a flow deflection element is shown in Figure 1 The flow deflection element 10 is shown and labelled 10. It serves to reduce the noise emission of the cleaning device. Such flow deflection elements are therefore also referred to as sound deflectors. The task of the flow deflection element 10 is to achieve the highest possible acoustic loss. At the same time, however, the flow rate at the air guide should not be significantly impaired by the flow passing through the at least one flow deflection element 10.

[0092] Furthermore, it is advantageous if flow noise generated in the flow deflection element 10 itself during operation of the cleaning device is as low as possible.

[0093] The flow deflection element 10 is designed as a pipe 12 with a flowable interior 14. The flow deflection element 10 has a first pipe arm 16 and a second pipe arm 18.

[0094] In one embodiment, the first pipe arm 16 extends in a first direction 20. The second pipe arm 18 extends in a second direction 22.

[0095] In particular, the first pipe arm 16 extends outside a transition area 24 into the second pipe arm 18 straight along the first extension direction 20. Similarly, the second pipe arm 18 extends outside the transition area 24 into the first pipe arm 16 straight along the second extension direction 22.

[0096] The first pipe arm 16 and the second pipe arm 18 are oriented transversely and, in particular, perpendicularly to each other. The first extension direction 20 and the second extension direction 22 are transverse to each other and, in particular, perpendicular to each other.

[0097] The first pipe arm 16 has a first opening 26. The first opening 26 is spaced apart from the transition area 24. The second pipe arm 18 has a second opening 28. This is spaced apart from the transition area 24.

[0098] Sound is coupled into the pipe 12 at the first opening 26. Sound is coupled out of the pipe 12 at the second opening 28.

[0099] The first opening 26 can be an inlet opening for an airflow and the second opening 28 an outlet opening for the airflow, or the second opening 28 is an inlet opening for the airflow and the first opening 26 is an outlet opening.

[0100] The flow deflection element 10 is acoustically connected to the air guide of the cleaning device via the first opening 26, specifically on the inlet side for sound propagation. Furthermore, the flow deflection element 10 is acoustically connected to the air guide of the cleaning device via the second opening 28, specifically on the outlet side. This will be explained in more detail below with reference to embodiments of cleaning devices.

[0101] An airflow 30 flows in one direction during operation of the cleaning device, for example from the first opening 26 to the second opening 28, or from the second opening 28 to the first opening 26.

[0102] A (surface) normal of the first opening 26 is parallel to the first extension direction 20. A (surface) normal of the second opening 28 is parallel to the second extension direction 22.

[0103] The first opening 26 and the second opening 28 are aligned transversely and, in particular, perpendicularly to each other, according to the orientation of the extension directions 20 and 22.

[0104] In the embodiment according to Figure 1 The first opening 26 and the second opening 28 each have a square or rectangular cross-section, respectively. The first opening 26 and the second opening 28 each have an envelope at the respective opening 26 or 28, which is square or rectangular, respectively, with sides of this envelope coinciding with boundary sides of the respective opening 26 or 28.

[0105] The first pipe arm 16 has a uniform cross-section corresponding to the cross-section at the first opening 26, at least up to the transition area 24. Furthermore, the second pipe arm 18 has a uniform cross-section corresponding to the cross-section of the second opening 28, at least up to the transition area 24.

[0106] The first opening 26 has a first latitude H 1 in a first latitude direction 32. In a first depth direction 34, the first opening 26 has a first depth T 1. The first depth direction 34 is perpendicular to the first latitude direction 32.

[0107] The first opening 26 extends with a width H 1 in the first latitude direction 32 and with a depth T 1 in the first depth direction 34.

[0108] Accordingly, the second opening 28 has a width H 2 in a second latitude direction 36 and a depth T 2 in a second depth direction 38. The second depth direction 38 is perpendicular to the second latitude direction 36.

[0109] The first latitude direction 32 and the second latitude direction 36 lie transversely and, in particular, perpendicularly to each other.

[0110] The first depth direction 34 and the second depth direction 38 are at least approximately parallel to each other. The first depth direction 34 and the second latitude direction 36 are perpendicular to each other. The second depth direction 38 and the first latitude direction 32 are perpendicular to each other.

[0111] The first latitude direction 32 and the first depth direction 34 are each perpendicular to the first extent direction 20. The second latitude direction 36 and the second depth direction 38 are each perpendicular to the second extent direction 22.

[0112] The first latitude direction 32 is at least approximately parallel to the second extent direction 22. The first depth direction 34 is perpendicular to the second extent direction 22. The second latitude direction 36 is at least approximately parallel to the first extent direction 20. The second depth direction 38 is perpendicular to the first extent direction 20.

[0113] The flow deflection element 10 has a first boundary plane 40 and an opposing, spaced-apart second boundary plane 42. In one embodiment, the first boundary plane 40 and the second boundary plane 42 are parallel to each other ( Figure 1 The first width direction 32 and the second width direction 36 preferably lie on the same plane and are parallel to the first boundary plane 40 and the second boundary plane 42.

[0114] The first depth direction 34 and the second depth direction 38 lie transversely and, in particular, perpendicularly to the first boundary plane 40 and to the second boundary plane 42.

[0115] The flow deflection element 10 has an external corner region 44 and an internal corner region 46 at the transition region 24. At the external corner region 44, an edge 48 is formed between the first pipe arm 16 and the second pipe arm 18 for noise reduction. This edge 48 is a (straight) connecting line between opposite corners 50a, 50b of the flow deflection element 10. Corners 50a, 50b are located at a connection region of the first pipe arm 16 with the second pipe arm 18. Corner 50a lies on the second boundary plane 42, and corner 50b lies on the first boundary plane 40.

[0116] In one embodiment, an installation wall 52 is arranged in the interior space 14, which guides the flow along it and, with respect to the flow path, covers the edge 48 in the interior space 14. The installation wall 52 is flow-conducting and sound-permeable.

[0117] In particular, the installation wall 52 is curved towards the interior 14 with a radius R 0.

[0118] However, with regard to sound absorption, edge 48 is effective due to the sound permeability of the installation wall 52.

[0119] In one embodiment, the flow deflection element 10 comprises a curved wall 54 at the transition region 24 at the inner corner region 46. The wall 54 is curved at least towards the interior space 14 and is, for example, constantly curved and has a radius R 1.

[0120] In one embodiment, the inner radius R 1 of this curved wall 54 is greater than half the hydraulic diameter of the first pipe arm 16.

[0121] In principle, the first pipe arm 16 and the second pipe arm 18 can be positioned at an angle α to each other with respect to their extension directions 20, 22. Preferably, this angle α is 90°, meaning that the first extension direction 20 and the second extension direction 22 are perpendicular to each other.

[0122] In the Figures 2 and 3 The basic flow conditions that can develop during flow through the flow deflection element 10 (with edge 48 and an edge at the inner corner region 46) are shown schematically. In this context, reference is made to the unpublished discussion by Dominik Scholl, "Acoustic and aerodynamic phenomena in duct bends," Institute for Acoustics and Building Physics, University of Stuttgart, 2021, and in particular to Chapter 2, "Flow efficiency of duct bends." This document is expressly referenced.

[0123] A flow profile 56 during the flow of fluid through the first pipe arm 16 exhibits a near-wall velocity gradient.

[0124] In the outer corner area 44, a dead zone 58 for the flow zone can form. In the second pipe arm 18, a flow separation zone 60 can form at the transition area 24 following the inner corner area 46.

[0125] In the second pipe arm 18, a flow with a distorted flow profile 62 can generally form.

[0126] In particular, a secondary flow 64 can also occur in the second pipe arm 18 (compare Figure 3 ) form. In principle, turbulent flows that can form ( Figures 2 and 3 ), leading to undesirable pressure losses. Such pressure losses can be minimized by appropriate flow guidance, particularly with the curved wall 54 and the installation wall 52.

[0127] By coupling the flow deflection element 10 to the air guide device of the cleaning device, whereby the air guide device is in turn coupled to the noise source of the cleaning device, sound waves can in principle propagate through the pipe 12.

[0128] Sound waves fundamentally possess a basic mode that propagates in the x-direction (along the direction of propagation 20 or 22). Basic modes are in Figure 4 shown schematically in the row labelled (1).

[0129] In addition, transverse modes can form, which extend in a y-direction according to Figure 4 (see also Figure 1 ) and can propagate in a z-direction.

[0130] The x-direction is parallel to the latitude direction 32 or 36, the z-direction is parallel to the depth direction 34 or 38. Among the transverse modes, there are "latitude transverse modes," which propagate in the y-direction, and "depth modes," which propagate in the z-direction. The depth modes play a subordinate role in sound attenuation and will therefore not be discussed further. The depth modes are also in Figure 4 not shown.

[0131] Columns (2) and (3) show corresponding (wide) transverse modes (1st transverse mode, 2nd transverse mode) of sound propagation for different frequencies.

[0132] The frequency f1 is 3300 Hz, the frequency f2 is 6700 Hz, and the frequency f3 is 8000 Hz. The sound pressure level is shown. Transverse modes include the first order ("the first transverse mode") and higher orders, such as the second transverse mode, etc.

[0133] Transverse modes have a lower cutoff frequency below which they do not propagate or at which evanescent sound propagation occurs. Figure 4 A cross next to the sound pressure level curve indicates that the mode is evanescent, meaning it cannot propagate. This means, for example, that at frequency f1, the first fundamental mode (row (2)) and the second fundamental mode (row (3)) cannot develop, but only the fundamental mode.

[0134] It can be seen that at frequency f 2 the fundamental mode and the first transverse mode can form, and at frequency f 3 the fundamental mode, the first transverse mode and the second transverse mode can form.

[0135] A key element of the sound attenuation provided by the flow deflection element 10 is that fundamental modes at the transition region 24 and, in particular, at the outer corner region 44, are at least partially transformed into transverse modes. This results in a reduction of sound pressure or a transmission loss for sound pressure when exiting at the second opening 28 as the air passes through the flow deflection element 10.

[0136] In this context, reference is made to the dissertation by Dominik Scholl, details of which are given above.

[0137] Particularly to reduce pressure losses in the flow, it is advantageous if the flow deflection element 10 is designed to be flat, such that the second width H2 is greater than the depth T2, and in particular at least 1.2 times greater, and preferably at least 1.9 times greater. Correspondingly, the width H1 is designed to be greater than the depth T1. Reference is made in this context to WO 2018 / 068850 A1, to which explicit reference is made.

[0138] In a first aspect of the solution according to the invention, the first width H1 at the first opening 26 is larger than the second width H2 at the second opening 28, that is, the ratio H1 / H2 is greater than 1. It has proven advantageous if this ratio is greater than or equal to 1.2 and, in particular, greater than or equal to 1.4 and, in particular, greater than or equal to 1.5.

[0139] Furthermore, in order to still allow sufficient flow, it is advantageous if this ratio H1 / H2 is less than or equal to 3 and in particular less than or equal to 2.8 and in particular less than or equal to 2.6 and in particular less than or equal to 2.5.

[0140] It has been shown that it is particularly advantageous to achieve both sufficient flowability and sufficient sound reduction if the ratio H1 / H2 is in the range between (inclusive) 1.5 and 2.

[0141] In Figure 5 The total transmission loss TL for the sound pressure during flow through pipe 12 (with rectangular shape) is shown. The total transmission loss is the transmission loss integrated over all frequencies. Its dependence on the parameter H1 / H2, that is, on the ratio of the first width H1 to the second width H2, is shown.

[0142] This results in a total transmission loss of more than 5 dB(A) if this ratio is greater than 1. Generally, the greater this ratio, the greater the total transmission loss. However, large values ​​of this ratio no longer allow sufficient airflow (just as very small values ​​of this ratio do).

[0143] It is therefore advantageous if this ratio is greater than 1 and in particular greater than or equal to 1.5 and preferably less than or equal to 3 and in particular less than or equal to 2.

[0144] With optimized flow guidance (and relatively low pressure losses), this results in effective sound attenuation.

[0145] The transmission losses (integrated over all frequencies) due to the larger width H1 of the first aperture 26 compared to the width H2 of the second aperture 28 are attributable to the excitation of evanescent modes, particularly in the first tube arm 16. This results in additional peaks in the frequency-resolved transmission loss spectrum. Reference is made in this context to the aforementioned dissertation by Dominik Scholl, and in particular to sections 1.2.4 and 1.2.5.

[0146] The above relationships were described using square and rectangular cross-sections of the flow deflection element 10 (compare Figure 6(a) ). They also apply to other cross-sectional shapes of the flow deflection element 10.

[0147] In the Figures 6(b), (c), (d) Flow deflection elements 10' or 10" or 10‴ are shown.

[0148] In the case of the flow deflection element 10' according to Figure 6(b)The rectangular shape is rounded. The first opening 26' and the second opening 28' each have an envelope 66 (in Figure 6(b) (shown only for the second opening 28'), which is a rectangle. The widths H2 and H1 refer to this respective envelope 66.

[0149] In Figure 6(c) A flow deflection element 10" is shown, which has an oval or circular shape.

[0150] The first opening 26" and the second opening 28" each have a rectangular envelope 68. The widths H2 and H1 refer to the widths of this envelope 68.

[0151] In Figure 6(d)A flow deflection element 10‴ is shown, the cross-section of which has a recess and the shape of a figure eight lying on its side. The first opening 26‴ and the second opening 28‴ each have a rectangular envelope 70. The second width H 2 and the first width H 1 are each referred to this envelope 70.

[0152] The first aspect of the solution according to the invention, according to which the ratio of the first width H 1 and the second width H 2 is greater than 1, relates, if the corresponding openings are not themselves square or rectangular, to corresponding square or rectangular envelopes 66, 68, 70 at the respective openings 26' and 28' or 26" and 28" or 26‴ and 28"'.

[0153] In a second aspect of the solution according to the invention, transverse modes in the second tube arm 18 are selectively damped ( Figure 7 , 8 ).

[0154] The corresponding flow deflection element 10 is equipped with a mode filter device 72 for transverse modes. At least one mode filter 74 ( Figure 7(b) ) provided for transverse modes, which is arranged on the second tube arm 18.

[0155] The mode filter device 72 is specifically designed for the formation of transverse modes, that is, for transverse modes which occur under the geometric conditions according to Figure 4 propagate in the direction y.

[0156] Through the transition zone 24, propagating transverse modes can form in the second pipe arm 18, as described above. The mode filter device 72 with a mode filter 74 on the second pipe arm 18 allows for the targeted filtering of transverse modes to achieve a reduction in sound level (sound attenuation).

[0157] In principle, it is possible that a corresponding mode filter for transverse modes is also arranged on the first tube arm 16, whereby the decisive influence of a mode filter 74 for transverse modes lies in its positioning on the first tube arm 16.

[0158] In a first embodiment of a mode filter 74 for transverse modes, this mode filter 74 is designed as an absorption silencer 76. The absorption silencer 76 comprises sound absorption material 78, such as a foam material. The absorption material 78 is, in particular, designed or arranged as a layer.

[0159] The absorption material 78 is arranged on an inner side 80 of the second tube arm 18 such that it is flush with this inner side 80 or is recessed relative to this inner side.

[0160] It can generally be provided that the absorption material 78 is arranged over the entire inner cross-section on the inside 80 of the second tube arm 18.

[0161] It is also possible, and generally sufficient for filtering latitude transverse modes, if the mode filter 74 is positioned only along the second depth direction 38 for these transverse modes.

[0162] The absorption material 78 in its layer arrangement has a certain thickness M.

[0163] Furthermore, it has an extension with a length L in the second extension direction 22.

[0164] In principle, the mode filter 74 is designed to be spaced apart from the first pipe arm 16 by a distance D. The distance D lies between the mode filter 74 and an intersection area between the first pipe arm 16 and the second pipe arm 18 at the inner corner area 46.

[0165] It has proven advantageous if, in order to obtain effective filtering of transverse modes, this distance D is at least 0.1 times and preferably at least 0.15 times the first width H 1 of the first tube arm 16.

[0166] In particular, a spacing direction for this distance D is parallel to the second extension direction 22 or parallel to the first latitude direction 32 and perpendicular to the second latitude direction 38.

[0167] This distance is furthermore related to a side 82 of the first tube arm 16 at the inner corner area 46.

[0168] It has proven advantageous if the length L is at least 1.5 times and preferably at least 2.5 times the first width H 1 or the second width H 2.

[0169] In one embodiment, it is provided that the length L is at most 2.5 times the first width H 1 or the second width H 2.

[0170] It has also proven advantageous if the thickness M of the absorption material 78 is at least 0.1 times the first width H1 or the second width H2. In one embodiment, this thickness M is at most 0.3 times the first width H1 or the second width H2.

[0171] In a specific embodiment where the first width H 1 and the second width H 2 are equal, the thickness M is 0.2 H 1, the length L is 2·H 1, and the distance D is 0.2 H 1.

[0172] In Figure 8 The transmission loss over a normalized frequency fc for the arrangement shown is according to the arrangement as per Figure 7(a) The mode filter 74 is shown. The normalized frequency fc is dimensionless and defined as 2 fH 1 / c, where c is the speed of sound and f is the frequency.

[0173] In Figure 8The transmission loss for sound propagation from B to A (i.e., from the first opening 26 towards the second opening 28) and in the reverse direction (i.e., from the second opening 28 to the first opening 26) is shown. The effectiveness of increasing the transmission loss by providing the mode filter 74 on the second tube arm 18 when the flow is from the first opening 26 to the second opening 28 is evident.

[0174] The comparison of the diagrams reveals the effectiveness of the sound attenuation through the transition area 24 (due to the transverse arrangement of the first tube arm 16 and the second tube arm 18) and then from Figure 8 the effectiveness of the mode filter 74 on the second tube arm 18, whereby the flow then exits at the second opening 28 on the second tube arm 18.

[0175] In this context, reference is made to the above-mentioned dissertation by Dominik Scholl, and in particular to chapter 1.4.2.

[0176] In one embodiment, the mode filter device 72 comprises a mode filter 84 for transverse modes, which is a chamber silencer ( Figure 7(b) ).

[0177] The mode filter 84 comprises a chamber 86, which is arranged on the second tube arm 18 and is spaced at a distance D from the first tube arm 16 and is located on a side 88 of the first tube arm 16, which is located at the inner corner area 46.

[0178] The chamber 86 forms, in a sense, an extension of the second tube arm 18. The chamber 86 has a width W which is greater than the second width H 2 of the second tube arm 18 outside the chamber 86; the chamber 86 forms a cross-sectional extension of the second tube arm 18.

[0179] In principle, this extension can be located on any side. For mode filtering of lateral and transverse modes, it is sufficient if the chamber 86 has the same depth T 2 as the second tube arm 18 and is only extended in the second lateral direction 36.

[0180] The mode filter 84 (the chamber silencer 84) has a length L parallel to the second extension direction 22.

[0181] It is specifically provided that the distance D is at least 0.1 times and preferably at least 0.3 times the width H1 or H2.

[0182] In a specific embodiment, the distance D is located at H1 or H2.

[0183] It is provided that the width W of chamber 86 in the second lateral direction 36 is greater than the first width H 1 or the second width H 2. In particular, the width W is at least twice as large as the first width H 1 or the second width H 2.

[0184] In one specific embodiment, the width W is 3.15 H 1 and in another specific embodiment, the width W is 2.87 H 2, where in this specific embodiment the first width H 1 and the second width H 2 are the same.

[0185] Furthermore, it is provided that the length L of chamber 86 is greater than the first width H 1 or the second width H 2 and is at least 1.2 times greater.

[0186] In one specific embodiment, the length is L = 1.42 x H1 (with W = 3.15 H1). In another specific embodiment, the length is L = 4.2 H1 (with W = 2.7 H1).

[0187] In both of the aforementioned specific embodiments, the distance D = H 1 .

[0188] The mode filter device 72 with the mode filter 84 for transverse modes has basically the same effects as the mode filter 74. Transverse modes of the first order and also of higher orders are attenuated by the mode filter 84.

[0189] Another embodiment of a mode filter is a device (90) provided with perforations, which is arranged on the second tube arm 18 ( Figure 7(c) ).

[0190] This 90° mode filter for transverse modes is used in one embodiment ( Figure 7(c) ) a plate 93 provided with openings 91. The plate 93 is arranged within the second tube arm 18 and is oriented, in particular, parallel to the second depth direction 38; the mode filter 90 with the perforated plate 93 is oriented transversely and, in particular, perpendicularly to the first width direction 32. A plane of the mode filter 90 is, in a sense, spanned by vectors in the second depth direction 38 and the second extension direction 22.

[0191] Preferably the perforated plate 93 is arranged centrally such that its distance to opposite sides 92a, 92b of the second tube arm 18 is equal.

[0192] The mode filter 90 (the plate 93) is located at a distance D from the first tube arm 16 (see above for mode filters 74 and 84).

[0193] This distance D is in particular at least 0.1 times the first width H 1 or the second width H 2 .

[0194] The openings 91 of the plate 93 are arranged in particular such that they are open in the second width direction 36.

[0195] It is intended that the openings 91 in the plate 93 have an opening width which is less than or equal to 1 mm.

[0196] It is further specifically stipulated that the opening density should be greater than or equal to 10 openings per square centimeter.

[0197] Furthermore, it is stipulated that the wall thickness (parallel to the second width direction 36) of the plate 93 shall be at least 1 mm.

[0198] At the in Figure 7(c) In the illustrated embodiment, the perforated plate 93 is arranged within the second tube arm 18. Fluid flow can pass over the plate 93 on both sides. It is also possible to provide a plurality of such plates, which are arranged in the interior space 14. In particular, adjacent plates 93 are spaced apart from each other, and fluid can flow between adjacent plates. It is specifically provided that each of these plates 93 is aligned parallel to the second extension direction 22.

[0199] A corresponding plate 93 is, for example, designed as a sheet metal part.

[0200] Alternatively or additionally, the perforated device 90 may also comprise one or more open-pore structures. The corresponding pores in the open-pore structure form openings which preferably have the parameters mentioned above (opening width less than or equal to 1 mm; opening density greater than or equal to 10 openings per square centimeter; wall thickness greater than or equal to 1 mm). The open-pore structure is, for example, designed as a block which is arranged accordingly in the interior 14 on the second tube arm 18. The open-pore structure is, for example, a foam structure and, in particular, an absorber foam structure. When an absorber foam structure is provided, sound absorption (in addition to the "cross-mode cancellation") can also take place at the perforated device 90.

[0201] The open-pore structure can also be, for example, a fiber material structure such as a nonwoven fabric, a woven fabric or a knitted fabric.

[0202] In a third aspect of the solution according to the invention, the installation wall 52 is provided (compare Figure 10 ).

[0203] Basically, it is intended that, as described above, the first pipe arm 16 and the second pipe arm 18 of the flow deflection element 10 meet at the outer corner area 44 in an edge 48 (compare Figure 9(a) This results from effective sound dampening.

[0204] For flow guidance, it is advantageous to have a "smooth" wall along which the flow is guided and which is particularly free of edges ( Figure 9(b) ).

[0205] In the third aspect of the solution according to the invention, it is provided that the first pipe arm 16 and the second pipe arm 18, as already described above, are connected by means of the flow deflection element 10 according to Figure 1 described, with an edge 48 meeting in an outer corner area 44.

[0206] The mounting wall 52 is arranged in the interior space 14. The mounting wall 52 covers the edge 48 in the interior space 14.

[0207] In one embodiment, the installation wall 52 is curved towards a flow area 94, which is located in the interior 14 (and concave towards the flow area 94).

[0208] The installation wall 52 fits smoothly and, in particular, without edges against a corresponding wall 96 of the first pipe arm 16, and against a corresponding wall 98 of the second pipe arm 18.

[0209] The installation wall 52 transitions tangentially into the wall 96 and the wall 98; if the transition is described by a corresponding curve, this curve is continuously differentiable at the transition.

[0210] The airflow, which is guided through the corresponding flow deflection element 10, is directed along a side 100 of the installation wall 52, which is located upstream of the edge 48 and which faces the flow area 94. The flow is thereby "kept away" from the edge 48.

[0211] The installation wall 52 is designed to be flow-conducting and permeable to sound (at the sound frequencies occurring at the corresponding noise source). This permeability is achieved through perforations (openings).

[0212] In one embodiment, the installation wall is formed by a wall element 102, which is, for example, a perforated sheet metal part. This is then positioned accordingly in the interior 14 of the flow deflection element 10.

[0213] The perforations are openings from the flow area 94 towards the edge 48.

[0214] The width of the corresponding openings is in particular greater than λ / 50, where λ is a typical upper sound wavelength for which sound attenuation is to take place.

[0215] In an alternative embodiment, the installation wall 52 is formed by a porous element 104 and a porous foam element. This has openings from side 100 to edge 48, the width of which is particularly greater than λ / 50.

[0216] In a specific embodiment, the installation wall on side 100 is constantly curved, i.e., circularly curved. A center point 106 of a corresponding circle of curvature lies between the first pipe arm 16 and the second pipe arm 18.

[0217] As described above, it is advantageous if the corresponding transition wall at the inner corner area 46 is also curved (curved wall 54). It can be provided that this curved wall 54 has a constant curvature R 1 (which is, in particular, greater than half the hydraulic diameter of the first opening 26 of the first pipe arm 16).

[0218] In one embodiment, the center point of the corresponding circle of curvature of the curved wall 54 coincides with the center point 106.

[0219] This results in effective flow guidance.

[0220] In a specific embodiment, side 100 and an inside side of the curved wall 54 are parallel to each other.

[0221] If the first width H1 is greater than the width H2, it may also be provided that side 100 and the inside of the curved wall 54 are not parallel.

[0222] The installation wall 52 has an extent in the first depth direction 34 and the second depth direction 38. The circle of curvature is, in a sense, a curved cylinder with a cylinder axis parallel to the first depth direction 34 and the second depth direction 38.

[0223] In another embodiment (compare Figure 11 An installation wall 52' is provided, which is not curved and runs straight between the first pipe arm and the second pipe arm. The installation wall 52' is formed, for example, by a surface element positioned between the first pipe arm and the second pipe arm, or is realized by a corresponding prismatic element made, for example, of a foam or fiber material.

[0224] The foam material or fiber material can also be designed as an absorber material for sound absorption.

[0225] A flow deflection element 10 in the third aspect of the solution according to the invention with the installation wall 52 results in effective flow guidance, in which pressure losses can be kept low.

[0226] For sound insulation, edge 48 is located in the interior. 14 Effective. In a sense, the disadvantage for airflow caused by edge 48 into the interior is thus eliminated. 14 The flow is compensated for by the installation wall 52. The flow guidance during the flow through the flow deflection element 10 is improved, while effective sound attenuation is still maintained.

[0227] Above, three aspects for effective sound attenuation (while minimizing pressure losses during flow guidance) were discussed: firstly, an increased first width H1 compared to the second width H2; secondly, the provision of one or more mode filters for transverse modes on the second pipe arm 18; and thirdly, the provision of the installation wall 52, which defines the edge 48 in the interior. 14 for flow guidance while remaining sound-permeable.

[0228] These aspects are fundamentally independent of each other, and no interfering effects of these different designs were found. Therefore, it can be expected that a combination of these aspects will result in sound attenuation. It is possible to combine the first aspect with the second, the second aspect with the third, the first aspect with the third, or all three aspects together.

[0229] In Figure 11 A flow deflection element 108 is shown schematically, in which all three aspects are realized.

[0230] A width H 1 at a first opening 110 of a first pipe arm 112 is greater than a width H 2 at a second opening 114 of a second pipe arm 116. The second pipe arm 116 is oriented transversely and, in particular, perpendicularly to the first pipe arm 112, with an edge 120 at an outer corner region 118.

[0231] A mode filter 122 for transverse modes (first transverse modes, second transverse modes, etc.) is arranged on the second pipe arm 116, in particular spaced apart from the first pipe arm 112.

[0232] A curved mounting wall 126 is arranged in an interior space 124 of the flow deflection element 108. This wall covers the edge 120 in the interior space 124 towards a flow area 128 and is flow-guiding. The mounting wall 126 is permeable to sound, thus providing effective sound attenuation.

[0233] At an inside corner area 130, a corresponding transition wall 132 is curved (in particular with an inside radius which is larger than half the hydraulic diameter of the first opening 110).

[0234] In principle, it can also be provided that the flow deflection element 108 is designed "flat", as described above, with the widths H 1 , H 2 being greater than depths perpendicular to them (compare WO 2018 / 068850 A1).

[0235] With regard to the aforementioned aspects of the invention, explicit and full reference is made to the dissertation by Dominik Scholl, details of which are shown above.

[0236] A flat design of the flow deflection element can be advantageous for flow efficiency and also for broadband transmission losses.

[0237] In the Figures 12 to 47 These are exemplary embodiments of cleaning devices with (at least) one corresponding flow deflection element in which one or more of the above-mentioned aspects of the invention are implemented.

[0238] One embodiment of a cleaning device is a suction device 134 ( Figures 12 to 15The vacuum cleaner 134, for example, is a stand-alone vacuum cleaner. This vacuum cleaner includes a blower 136, which generates a suction flow. This suction flow is applied to a suction hose 138. A filter unit 140 is provided, through which the suction flow from the cleaning device 134 passes.

[0239] An air distribution unit 142 is connected to the blower 136. Process air is discharged through this air distribution unit 142. This process air is the exhaust air from the blower 136. It is air that has been cleaned by the filter unit 140.

[0240] This air guidance device 142 has a flow deflection element 10 as described above. In the schematic embodiment according to Figure 12The air guidance device 142 is formed by such a flow deflection element, wherein the first opening 26 is directly connected to an outlet of the blower 136, and wherein the second opening 28 opens into the outside space.

[0241] The air guidance device 142 can also include such a flow deflection element 10 as a component.

[0242] The blower 136 itself, which generates the corresponding airflow in the air guidance device 142, is in this case also the noise wave which is sound-emitting.

[0243] The flow deflection element 10 of the air guidance device 142 provides appropriate sound attenuation, whereby, as described above, the pressure loss is minimized during flow guidance.

[0244] In Figure 12A sound deflection element 10 is shown schematically, in which the ratio of the first width H 1 at the first opening 26 to the second width H 2 at the second opening 28 is greater than 1.

[0245] The blower 136 comprises a blower motor 144, to which a cooling fan 146 is assigned. The cooling fan serves to cool the blower motor 144, in particular with air; the blower motor 144 is air-cooled.

[0246] A corresponding air guidance device 148 is provided for this purpose, which may also be equipped with a flow deflection element 150. There, the direction of sound propagation is opposite to the direction of the flow.

[0247] For example, a mode filter 74 can be arranged on the second pipe arm 18 of the flow deflection element 10 or 150 ( Figure 13 , 14 ).

[0248] It is also possible, for example, that the flow deflection element 10 is provided with an installation wall 52.

[0249] The flow deflection element 150 can also be equipped with a mode filter for transverse modes on a flow arm, which is an inlet arm.

[0250] In the Figures 16 to 19 A high-pressure cleaner 152 is shown schematically as an embodiment of a cleaning device. It includes a motor 154 as a noise source. The motor 154 is air-cooled, and an air guide device 156 is provided.

[0251] The air guidance device 156 includes in particular a flow deflection element 10, which is located downstream of the motor 154 on the inlet side and leads to the outside space on the outlet side.

[0252] The flow deflection element 10 can be designed as described above and, for example, have a greater width at a first opening 26 than at a second opening 28 ( Figure 16 It may be equipped with a mode filter 74 ( Figure 17 , 18 It can be equipped with a mounting wall 52 ( Figure 19 ).

[0253] Another embodiment of a cleaning device is a wet floor cleaner 158, which is in particular hand-held or hand-guided ( Figures 20 to 23 In particular, a standing operator can guide this wet floor cleaner 158 over a floor to be cleaned.

[0254] The wet floor cleaner 158 comprises at least one cleaning roller 160, which is in particular a textile roller. Cleaning fluid is supplied to the at least one cleaning roller.

[0255] A blower 162, which is a suction blower, is provided. This blower is used to draw fluid from the cleaning roller 160. The fluid is cleaning fluid containing dirt particles.

[0256] A corresponding dirt collection container 164 with an associated and, for example, integrated separator is provided.

[0257] The blower 162 comprises a blower motor 166 as the noise source. This motor is air-cooled. An air guidance device 168 is provided, which includes a flow deflection element 10 according to the invention.

[0258] In the illustrated embodiment, the flow deflection element 10 itself forms the air guide device 168.

[0259] It can then be provided in particular that a first width of the flow deflection element 10 on the inlet side is larger than an outlet-side opening 28 ( Figure 20 ). A mode filter 74 can be attached to the corresponding second pipe arm 18 ( Figure 21 , 22 ) are planned.

[0260] A mounting wall 52 can be arranged on the flow deflection element.

[0261] Another embodiment of a cleaning device according to the invention is a window vacuum cleaner 170 ( Figures 24 to 27 ).

[0262] This window vacuum cleaner includes a blower 172 in the form of a suction blower.

[0263] Exhaust air from the blower is discharged into an air distribution device 174. The blower 172 (with a blower and / or a corresponding impeller) is a noise source.

[0264] The air guidance device 174 comprises a flow deflection element 10, on which at least one of the aspects according to the invention (ratio of the first width to the second width, mode filter for transverse modes on the second tube arm, installation wall) is realized.

[0265] Another embodiment of a cleaning device according to the invention is a leaf blower 176 ( Figures 28 to 31 ).

[0266] This leaf blower comprises a blower 178, which generates a blowing stream 180. Air (for generating the blowing stream 180) is supplied to the blower 178 via an air guide device 182.

[0267] The air guidance device 182 is or comprises a flow deflection element 10 which is designed according to at least one of the aspects mentioned above.

[0268] Another embodiment of a cleaning device according to the invention is a sweeper 184, which is located in the Figures 32 to 35 The embodiment of a ride-on sweeper is shown schematically. This sweeper 184 includes a blower 186 as a noise source. An air guidance device 188 is connected to the blower 186, which is or comprises a sound angle 10 according to the invention.

[0269] In particular, an input width is larger than an output width ( Figure 32 ), and / or a mode filter for cross modes is provided ( Figures 33 ,34 ), and / or a built-in wall 52 is provided ( Figure 35 ).

[0270] Another embodiment of a cleaning device according to the invention is a scrubbing machine 190, wherein in the Figures 36 to 39 A trailed floor cleaning machine is shown. This machine includes a blower 192 for generating a suction flow. The blower 192 forms the noise source. The blower 192 includes an air guide 194 for exhaust air. This air guide 194 is or includes a flow deflection element 10 according to the invention.

[0271] Another embodiment of a cleaning device according to the invention is a municipal vehicle 196 ( Figures 40 to 43 This is, for example, designed as an articulated vehicle. It comprises a blower 198 with an air guide for exhaust air, wherein a flow deflection element is connected to this air guide.

[0272] Another embodiment of a cleaning device according to the invention is a washing portal 200, particularly for vehicles ( Figures 44 to 47 This washing portal 200 includes a blower 202, which generates a blowing stream 204. A vehicle can be dried using this blowing stream 204.

[0273] For the airflow, a corresponding air guidance device 206 is provided, which is equipped with a flow deflection element 10 according to the invention.

[0274] Furthermore, an air guide device 208 is provided, through which air is supplied to the blower 198. A flow deflection element 10 according to the invention can also be located on this air guide device 208. Reference symbol list

[0275] 10, 10', 10", 10‴Flow deflection element 12Pipe 14Interior 16, 16', 16", 16‴First pipe arm 18, 18', 18", 18‴Second pipe arm 20First extension direction 22Second extension direction 24Transition area 26, 26', 26", 26‴First opening 28, 28', 28'', 28‴Second opening 30Airflow 32First width direction 34First depth direction 36Second width direction 38Second depth direction 40First boundary plane 42Second boundary plane 44Outer corner area 46Inner corner area 48Edge 50aCorner 50bCorner 52, 52'Installation wall 54 Curved wall 56 Flow profile 58 Dead zone 60 Flow separation zone 62 Flow profile 64 Secondary flow 66 Envelope 68 Envelope 70 Envelope 72 Mode filter device 74 Mode filter (absorption silencer) 76 Absorption silencer 78 Absorption material 80 Inside 82 Side 84 Mode filter (chamber silencer) 86 Chamber 88 Side 90 Mode filter (perforated device) 91 Opening 92a Side 92b Side 93 Plate 94 Flow area 96 Wall 98 Wall 100 Side102 Wall element 104 Porous element 106 Center point 108 Flow deflection element 110 First opening 112 First pipe arm 114 Second opening 116 Second pipe arm 118 External corner area 120 Edge 122 Mode filter 124 Interior 126 Mounting wall 128 Flow-through area 130 Internal corner area 132 Transition area 134 Vacuum unit 136 Blower 138 Suction hose 140 Filter unit 142 Air guide unit 144 Blower motor 146 Cooling fan 148 Air guide unit 150 Flow deflection element 152 High-pressure cleaner 154 Motor 156 Air guide unit 158 ​​Wet floor cleaner 160 Cleaning roller 162 Blower 164 Dirt collection container 166 Blower motor 168 Air guide device 170 Window vacuum 172 Blower 174 Air guide device 176 Leaf blower 178 Blower 180 Blowing stream 182 Air guide device 184 Sweeper 186 Blower 188 Air guide device 190 Scrubber 192 Blower 194 Air guide device 196 Municipal vehicle 198 Blower 200 Wash gantry 202 Blower 204 Blowing stream 206 Air guide device 208 Air guide device

Claims

1. Cleaning apparatus, comprising at least one noise source, and an air guidance device having at least one flow deflection element (10), wherein the at least one flow deflection element (10) has a first duct arm (16) with a first opening (26) and a second duct arm (18) with a second opening (28), and wherein the second duct arm (18) is oriented transversely to the first duct arm (16), characterized in that a ratio (H1 / H2) of a first width (H1) of the first opening (26) to a second width (H2) of the second opening (28) is greater than 1.

2. Cleaning apparatus as claimed in claim 1, characterized in that the ratio (H1 / H2) is greater than or equal to 1.2, and in particular greater than or equal to 1.4 and in particular greater than or equal to 1.5.

3. Cleaning apparatus as claimed in claim 1 or 2, characterized in that the ratio (H1 / H2) is less than or equal to 3, and in particular less than or equal to 2.8, and in particular less than or equal to 2.6, and in particular less than or equal to 2.5.

4. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that the ratio (H1 / H2) is between 1.5 and 2.

5. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that at least one of the following applies: - the first duct arm (16) extends in a first direction (20) of extent that is a direction normal to the first opening (26); - the second duct arm (18) extends in a second direction (22) of extent that is a direction normal to the second opening (28); - the first direction (20) of extent and the second direction (22) of extent are transverse and in particular perpendicular to one another; - a first width direction (32), in which the first width (H1) is measured, is transverse and in particular perpendicular to the first direction (20) of extent; - a second width direction (36), in which the second width (H2) is measured, is transverse and in particular perpendicular to the second direction (22) of extent; - the first width direction (32) and the second direction (22) of extent are at least approximately parallel to one another; - the second width direction (36) and the first direction (20) of extent are at least approximately parallel to one another; - the first opening (26) has an extent in a first depth direction (34) that is perpendicular to the first width direction (32) and is transverse and in particular perpendicular to the second width direction (36); - the second opening (28) has an extent in a second depth direction (38) that is perpendicular to the second width direction (36) and is transverse and in particular perpendicular to the first width direction (32); - the first width direction (32) and the second width direction (36) lie in a plane to which the first depth direction (34) and the second depth direction (38) are oriented transversely and in particular perpendicularly.

6. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that at least one of the following applies: - the first width (H1) of the first opening (26) relates to a rectangular envelope (66; 68; 70) which has sides having an extent in a first width direction (32) and in a first depth direction (34) perpendicular to the first width direction (32), and the second width (H2) of the second opening (28) relates to a rectangular envelope (66; 68; 70) which has sides having an extent in a second width direction (36) and in a second depth direction (38) perpendicular to the second width direction (36); - the first opening (26) has a rectangular envelope (66; 68; 70) which has sides having an extent in a first width direction (32) and in a first depth direction (34) perpendicular to the first width direction (32), and the second opening (28) has a rectangular envelope (66; 68; 70) which has sides having an extent in a second width direction (36) and in a second depth direction (38) perpendicular to the second width direction (36).

7. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that at least one of the following applies: - the first duct arm (16) has a uniform cross section from the first opening (26) to a region (24) of transition to the second duct arm (18); - the second duct arm (18) has a uniform cross section from the second opening (28) to a region (24) of transition to the first duct arm (16); - the first opening (26) has a rectangular or square cross section; - the first duct arm (16) has a rectangular or square internal cross section; - the second opening (28) has a rectangular or square cross section; - the second duct arm (18) has a rectangular or square internal cross section.

8. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that at least one of the following applies: - the second width (H2) of the second opening (28) is at least 1.2 times as large as a second depth (T2) of the second opening (28) in a second depth direction (38) perpendicular to a second width direction (36) in which the second width (H2) is measured, and is in particular at least 1.9 times as large; - the first width (H1) of the first opening (26) is at least 1.2 times as large as a first depth (T1) of the first opening (26) in a first depth direction (34) perpendicular to a first width direction (32) in which the first width (H1) is measured, and is in particular at least 1.9 times as large.

9. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that, at an external corner region (44), the first duct arm (16) and the second duct arm (18) have a common edge (48) that extends in a depth direction (34; 38) transversely to a first width direction (32) and transversely to a second width direction (36).

10. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that a region of transition (24) between the first duct arm (16) and the second duct arm (18) has a curved wall (54), in particular having at least one of the following: - the curved wall (54) lies opposite a common edge (48) of the first duct arm (16) and the second duct arm (18); - an internal radius (R1) at the curved wall (54) is greater than half of a hydraulic diameter of the first duct arm (16).

11. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that at least one of the following applies: - the at least one noise source is a fan or pump; - the air guidance device is a guidance device for process air or cooling air; - the air guidance device is a guidance device for cleaning air, and in particular blown air; - the air guidance device is a guidance device for drying air; - at least one tool for application to a surface that is to be cleaned is provided which is is coupled to the air guidance device in particular.

12. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that, during operation of the cleaning apparatus, there is sound propagation from the first duct arm (16) to the second duct arm (18), and in that a mode filter device (72) for transverse modes of sound propagation is arranged at the at least one flow deflection element (10), having at least one mode filter (74; 84; 90) that is positioned at the second duct arm (18).

13. Cleaning apparatus as claimed in any one of the preceding claims, characterized in that the first duct arm (16; 112) and the second duct arm (18; 116) have a common edge (48; 120) at an external corner region (44; 118), in that arranged in an interior (14; 124) of the at least one flow deflection element (10; 108) is a built-in wall (52; 52'; 26) which covers the edge (48; 120) in the interior (14; 124), in that the built-in wall (52; 52'; 126) faces a through-flow region (128) in the interior (14; 124), and in that the built-in wall (52; 52'; 126) takes a form such that it guides flow and is sound-permeable.

14. Use of a flow deflection element (10) that has a first duct arm (16) with a first opening (26) and a second duct arm (18) with a second opening (28), wherein the second duct arm (18) is oriented transversely to the first duct arm (16) and a ratio (H1 / H2) of a first width (H1) of the first opening (26) to a second width (H2) of the second opening (28) is greater than 1, in the case of a cleaning apparatus with a noise source.

15. Use as claimed in claim 14, characterized in that the ratio (H1 / H2) is between 1.5 and 2.