FAN MODULE AND ARRANGEMENT OF ONE OR MORE SUCH FAN MODULES IN A FLOW CHANNEL

Description

[0001] The present invention relates to a fan module and the arrangement of one or more such fan modules in a flow channel or a comparable air handling system, wherein the fan module has a device on the pressure side for reducing or suppressing a backflow of the outgoing air.

[0002] The term "fan" is to be understood in the broadest sense. It typically refers to radial, diagonal, or axial fans. When used in modular systems, such fans are arranged in housings or connected on the pressure side to flow channels that direct the airflow, usually in an axial direction. These flow channels typically have a rectangular cross-section, especially a square or round one.

[0003] In practice, flow channels often have a relatively small cross-section compared to the fan diameter, or the side walls of the flow channels, which deflect the air flowing from the fan in the axial direction, are positioned relatively close to the fan outlet. This results in significant flow losses in free-running fans. For example, in a square or rectangular channel, the distance between opposing side walls is equal to or less than 1.6 times the maximum fan blade diameter of an installed fan. These flow losses are due to the formation of a backflow in a central or axially close area behind the fan, which induces a large, torus-shaped vortex. This leads to significant power losses and noise generation. The losses increase with the narrower or smaller the channel.Similarly, losses occur when adjacent, parallel-connected radial or diagonal fans are close together, causing the outgoing air to be quickly deflected along the axis. To counteract these losses, it is already known in practice to use guide vanes to remove the swirl from the flow, thereby significantly reducing flow losses. The use of guide vanes is structurally complex. Furthermore, the use of guide vanes increases noise emissions. For an example of the relevant prior art, reference is made to DE 195 23 339 A1, which specifically describes an axial fan arranged in a housing with a guide vane, intended to stabilize the airflow generated by the impeller. Accordingly, the guide vane is located on the pressure side of the fan.

[0004] From EP 0 497 296 B1, a generic arrangement is known in which a fan is arranged in a housing. On the pressure side, several relatively thick partition walls are provided, forming two square annular channels with a small flow cross-section, arranged concentrically. A filter is located downstream on the pressure side. The inner wall sections consist of a sound-absorbing material for the purpose of noise reduction of the unit. Furthermore, the nested annular channels ensure a uniform flow distribution.

[0005] From DE 3 513 902 A1, a space-saving arrangement of a fan and filter for use in cleanroom areas is known. To improve the efficiency of the fan and filter arrangement, an intermediate guide vane arrangement is provided between the fan and the filter element, which influences a radial airflow between the fan and the filter element. A sound-insulating and damping material is provided on the back of the intermediate guide vane arrangement.

[0006] A low-noise fan filter unit is known from DE 299 12 274 U1. The fan filter unit has a noise reduction device with a flow guide plate located below the fan and extending radially along the fan. The flow guide plate forms a curved air channel by directing the airflow, which moves radially along the fan, towards the filter. Additionally, a noise reduction plate is provided between the flow guide plate and the filter.

[0007] A disadvantage of the previously described arrangement is that the provision of the wall sections and the creation of relatively narrow ring channels result in significant flow losses. If the partition walls were not made of sound-absorbing material, considerable flow noise would be generated.

[0008] Furthermore, due to their geometry and arrangement, the partition walls have a considerable axial extent, requiring a significant amount of axial installation space together with the fan. This is particularly disadvantageous when the fan is to be housed in a modular enclosure.

[0009] In light of the foregoing, the present invention aims to eliminate, as far as possible, the disadvantages known in the prior art. In particular, it should enable quiet operation while avoiding flow losses. Furthermore, the fan module and the arrangement of fan modules should differ from competing products in design and construction.

[0010] The foregoing problem is solved by the features of dependent claims 1 and 7. According to these claims, the fan module comprises a fan arranged in a housing. An arrangement consists of one or more fan modules, which are arranged in a modular combination to form a blower wall, and, depending on the embodiment, a flow channel or a comparable air handling system into which the fan module(s) is / are installed, wherein the flow channel regularly has a rectangular, square, or round cross-section.

[0011] On the pressure side, a device is provided to reduce or suppress backflow, which serves to equalize the outgoing air.

[0012] The device consists of a mechanical backflow preventer positioned approximately centrally in the flow path, blocking a portion of the flow cross-section. The backflow preventer is a compact component with a relatively flat design and a small axial size.

[0013] The backflow restrictor is designed as a flat box (flat in the axial direction) whose effective surface runs transversely or orthogonally to the flow direction. The backflow restrictor presents an obstacle in the flow path but does not itself create any additional flow paths or channels. With respect to the airflow, the backflow restrictor is self-contained. Specifically, the backflow restrictor blocks a portion of the flow cross-section, leaving an annular channel between the side walls of the housing and the restrictor as an air passage. In the area of ​​the annular channel, the backflow restrictor has an axial height greater than 5% of the width of the housing and is no greater than 20% of the axial height of the fan module.

[0014] In a further advantageous embodiment, the backflow preventer has essentially the same or a similar contour or cross-sectional shape as the housing or the flow channel. This means that, for example, with a square flow channel, the backflow preventer has a square base. With a circular flow channel, the backflow preventer is correspondingly equipped with a circular cross-section.

[0015] In a particularly advantageous embodiment, the backflow preventer has a preferably central recess or passage. When the backflow preventer is installed, a portion of the fan motor projects into or through this recess, allowing the backflow preventer to be arranged or positioned so that it does not protrude beyond the end of the fan on the pressure side. This design has the significant advantage that the overall size of the assembly is not increased in the axial direction by the inclusion of the backflow preventer, meaning the assembly can have a maximum axial size equal to that of the fan.

[0016] Furthermore, it is conceivable that the backflow preventer is designed in a frame-like form, with the portion of the fan projecting into or through the backflow preventer located within the frame legs on the pressure side and protected at least laterally. In addition, the surrounding frame promotes the formation of the flow path while preventing turbulence.

[0017] The backflow blocker is advantageously dimensioned such that it reduces the effective flow cross-section within the housing or flow channel by 40 to 70%, preferably by about 55%.

[0018] Compared to the state of the art, the backflow preventer achieves a significantly lower velocity spread and a homogeneous flow towards downstream components. This allows for a reduced distance to downstream components such as filters or heat exchangers. The homogeneous flow pattern also improves the functionality of downstream components due to the homogeneous flow, while at least slightly reducing pressure-side noise.

[0019] In principle, the backflow preventer can be manufactured from a sheet metal part, preferably with a flange or bent edge. It can also be made of plastic, either as a single piece or in multiple parts, with the individual components joined together using a joining technique. Furthermore, it is conceivable that the backflow preventer is manufactured as a sound-absorbing component, for example, as a perforated sheet metal part backfilled with sound-absorbing material, or entirely from a dimensionally stable sound-absorbing material, such as a foamed plastic with preferably open porosity.

[0020] The backflow preventer utilizes an existing fan mounting and is not load-bearing itself. The backflow preventer is clipped, snapped, or clamped onto the mounting. Any positive or non-positive connection between the backflow preventer and the mounting is possible, provided the attachment is reversible to facilitate access to the fan.

[0021] It should be noted that such a backflow preventer can be easily removed for maintenance or repair purposes of the fan.

[0022] It is also conceivable to retrofit a generic arrangement with a backflow blocker, for example by using the existing suspension of the fan.

[0023] The special mounting of the backflow preventer, or the mounting of the fan used by the backflow preventer, can be made of round material, which improves the flow conditions. In a particularly simple design, the mounting can consist of a flat sheet of metal, for example, sheet metal strips or bars, or even plastic.

[0024] In a further advantageous embodiment, the fluid dynamic function of the backflow blocker and the mechanical function of the fan suspension can be taken over by one and the same part, preferably a sheet metal part.

[0025] A particularly advantageous feature is the ability to reposition the backflow preventer or the fan's suspension within the housing or flow channel, either along the suspension itself or along positioning rails associated with it. This allows the otherwise identical fan module to be used with fans featuring different motors, impeller sizes, and impeller types, often with varying heights, without any further modifications.

[0026] As mentioned previously, the backflow preventer can be made of sheet metal or plastic, and the surface may be textured to enhance its effectiveness. If made of plastic, it may consist of open-pore foamed plastic.

[0027] In another advantageous embodiment of a fan module, a pressure-side touch protection is provided, which, in addition to the backflow blocker, is only necessary in the areas that are not shielded by the backflow blocker.

[0028] The arrangement according to the invention consists of one or more fan modules arranged side by side and connected in parallel, often in flow channels or similar air handling systems. Since the fan modules have a backflow preventer, they can be positioned relatively close to each other or close to the side walls of flow channels in a compact manner without significant flow losses. Such arrangements can optionally be formed from fan modules with or without a housing, the backflow preventer exerting its beneficial effect in either case. In the case of fan modules with a housing, adjacent fan modules can advantageously be connected to each other via the housing, in particular via the frame structure of the housing.

[0029] Any functional units can be downstream of the backflow preventer, which the backflow preventer positively affects by ensuring a more uniform flow. For example, a filter or filter group, or a heat exchanger or heating unit, can be downstream.

[0030] There are now various ways to advantageously elaborate and further develop the teaching of the present invention. For this purpose, reference should be made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of preferred embodiments of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawing, generally preferred embodiments and further developments of the teaching are also explained. The drawing shows Fig. 1 shows an embodiment of a fan module according to the invention in a perspective view, Fig. 2 shows the fan module in a pressure-side top view. Figure 1 Fig. 3 shows a further embodiment of a fan module according to the invention in a pressure-side top view, without a backflow preventer, with visible suspension of the fan; Fig. 4 shows the object in a perspective view. Figure 3 , however, with a backflow preventer installed, Fig. 5 in a pressure-side top view the object from Figure 4 , Fig. 6 in a side view, with the side panel removed, the fan module from the Figure 1 and 2 , Fig. 7 in a side view, with the side panel removed, the fan module from the Figures 3 to 5Fig. 8 in a perspective view, from the intake side, an example of a fan module not according to the invention, without a housing, for installation in a flow channel; Fig. 9 in a view, from the pressure side, the example according to Figure 8 , Fig. 10 in a side view the object from the Figures 8 and 9 , Fig. 11 in a print-side top view the object from the Figures 8 to 10 Fig. 12 shows a further embodiment of a fan module according to the invention in a housing with a downstream or integrated sound absorber in a perspective view, Fig. 13 shows the object in a pressure-side top view. Figure 12 , Fig. 14 in a side view, with the side wall removed, the object from the Figure 12 and 13, Fig. 15 in a perspective view another embodiment of a fan module according to the invention with touch protection grille, Fig. 16 in a perspective view a compact arrangement of 4 fan modules connected in parallel, and Fig. 17 in a perspective view another example of a fan module not according to the invention, in which the backflow blocker is integrated into the fan suspension.

[0031] Fig. 1 Figure 1 shows an embodiment of a fan module 24 according to the invention, wherein a radial fan, hereinafter referred to as fan 1, is arranged in a housing 2. The fan 1 can be of any type.

[0032] The fan module 24 is designed as a compact, modular component and can be part of an arrangement with one or more fan modules, which can advantageously be arranged directly next to and / or above one another, for example in a blower wall. This also results in a compact design.

[0033] The housing 2 has a frame structure 3, which is laterally closed by side walls 4. On the inlet side, the housing 2 is closed by a nozzle plate 5. An inlet nozzle 23 for the fan 1 is attached to or integrated into the nozzle plate 5. The fan module 24 can be mounted in a flow duct, an air handling system, or to another fan module via various elements of the housing 2, in particular via the nozzle plate 5, the frame structure 3, or the side walls 4.

[0034] Figure 1This clearly shows that a special device is provided on the pressure side (outlet side) for reducing or suppressing backflow and smoothing the outflowing air. This device is hereinafter referred to as the backflow blocker 6. It is a fluid-mechanical component that advantageously has an outer contour similar to the inner contour of the housing 2. In the exemplary embodiment, the contours of the housing 2 and the backflow blocker 6, viewed in cross-section perpendicular to the fan axis, are approximately square. They can also be rectangular or hexagonal, or have any other desired shape. The backflow blocker 6 occupies approximately 55% of the housing cross-section, leaving an annular channel 15 or air passage between the side walls 4 of the housing 2 and the backflow blocker 6.In other embodiments, the shape of the outer contour of the backflow blocker 6 may also differ significantly from the shape of the inner contour of the housing 2, as long as the backflow blocker occupies approximately 40%-70% of the housing cross-section.

[0035] As shown in the exemplary embodiment, the backflow preventer 6 advantageously has an axial height in the region of the annular channel 15, which is realized here by the frame 7. In particular, this axial height is greater than the sheet thickness, advantageously greater than 5% of the width of the housing in cross-section or greater than 20% of the mean width of the annular channel.

[0036] The backflow blocker 6 is nevertheless relatively thin in the axial direction compared to the axial height of the housing 2. To achieve optimal space savings, the axial height of the backflow blocker 6 is no greater than 20% of the axial height of the fan module 24. In the exemplary embodiment, it consists of a sheet metal part that is bent or crimped laterally to form a circumferential frame 7. This also contributes to the compact design.

[0037] A roughly circular recess 8 is provided in the center of the backflow preventer 6, through which part of the electric motor of the fan 1 protrudes. This makes it possible to slide or position the backflow preventer 6 over the fan 1 or its pressure-side end 9 so that the fan 1 itself determines the necessary axial length of the fan module 24, and not the backflow preventer 6 with its additional installation space.

[0038] Figure 1The figure further shows that the backflow preventer 6 is attached to a suspension 10 consisting of round struts 11. The fan 1 with its electric motor is also attached to this suspension, thus ensuring the connection of the fan 1 to the housing. The struts 11 are screwed to two side walls 4 each via angle brackets 12, thereby providing not only a suspension 10 for the fan 1 and the backflow preventer 6 but also stabilizing the housing 2. Thin sheet metal struts can also be used instead of the round struts 11 or the round material, with the use of round material promoting airflow and reducing flow resistance.

[0039] It should be noted that investigations have shown that the optimal geometry of the backflow preventer 6 does not depend, or at most only marginally depends, on the impeller type or impeller size of the fan 1. Rather, the primary factor is the ratio of the cross-sectional areas of the housing 2 and the backflow preventer 6, viewed in the axial direction. This finding allows the use of different fan impellers in the same housing or flow channel with the same backflow preventer 6, which has a positive impact on manufacturing costs and the variety of parts required.

[0040] Figure 1The figure further shows that the otherwise circular recess 8 has an enlarged recess 13 or notch in its lower area, through which an electronics / control area 14 of the fan 1 is accessible from the pressure side without removing the backflow preventer. Nevertheless, the backflow preventer 6 can be removed using the fasteners employed, allowing easy access to the entire fan 1. The cables can be routed through the recess 13 to enable easy removal of the backflow preventer without disconnecting the electrical connection cable.

[0041] Figure 2 The compact fan module 24 is shown. Figure 1 in an axial top view, i.e., from the pressure side. Based on Figure 2It can be roughly estimated that the backflow preventer 6 occupies approximately 55% of the cross-sectional area of ​​the housing 2. Furthermore, the backflow preventer 6 reduces the pressure-side noise level, and in the embodiment shown here, it is made of sheet metal. It is also conceivable to coat the backflow preventer 6 with sound-absorbing material or to manufacture it entirely from such material. It is also possible to manufacture the backflow preventer 6 from plastic, for example, using injection molding. Foamed plastic can be advantageously used to save weight and increase sound absorption. For molded backflow preventers 6, devices for attaching the backflow preventer to a suspension 10 can be integrated, allowing, for example, simple clipping onto the suspension 10.

[0042] Figure 3Figure 1 shows another embodiment of a fan module according to the invention, but without the backflow preventer 6, so that a suspension 10 for the fan 1 is clearly visible. The suspension 10 comprises vertical profiles 16 and lower and upper adjustment rails 17 for variable axial positioning. The adjustment rails 17 are equipped with elongated slots along which the suspension 10 can be moved along the profiles 16. This makes it possible to install two different fans with different axial heights in one housing. Thus, the same fan impeller can be used with different motor lengths, or fans of different designs or impeller types can be installed in the same housing.Since the ratio of its cross-section to the housing cross-section is crucial for the functioning of the backflow preventer, the same backflow preventer can be used for different fans.

[0043] Figure 4 The fan module shows after Figure 3 , however, with, for example, a subsequently installed backflow preventer 6. It is clearly evident that the axial position of the backflow preventer is always coupled to the axial position of the vertical struts 16 of the suspension 10. This allows a flow-optimized distance to the fan outlet to be achieved regardless of the fan used, without any special additional measures.

[0044] Figure 4Furthermore, it clearly shows that part 9 of the electric motor of the fan 1 protrudes into the backflow blocker 6 or through the recess 8 in the backflow blocker 6, so that the provision of the backflow blocker 6 does not in any way increase the required installation space and thus the volume of the housing 2, making it possible to retrofit conventional arrangements with a backflow blocker 6.

[0045] Figure 5 The fan module shows Figure 4 in an axial top view, i.e. from the pressure side.

[0046] Special clip elements, similar to those commonly used for installing cable conduits in electrical installations, have proven particularly advantageous for fastening sheet metal backflow preventers. These clip elements can be clipped into designated cutouts in the sheet metal of the backflow preventer 6 and onto round struts 11 of a suspension 10. It is also conceivable to use similar clip elements for flat material suspensions, which may have corresponding cutouts.

[0047] Figure 6 The fan module shows the Figure 1 and 2 From the side, with side panel 4 removed on this side. In the background, you can see the opposite side panel 4.

[0048] The backflow blocker 6 provided there prevents air from flowing back towards the fan 1 in a central, near-axis area. A torus-shaped, lossy vortex cannot form due to the provision of the backflow blocker 6.

[0049] Furthermore, it should be noted that in the embodiment shown here, the channel width is 1.6 times the maximum axle diameter of the impeller blades, with the range of this ratio typically being between 1.3 and 1.8.

[0050] Furthermore, it shows Figure 6 clearly shows the special suspension 10 provided there, which in the exemplary embodiment comprises round struts 11.

[0051] Figure 7 shows a view accordingly Figure 6 , whereby this view refers to the embodiment from the Figures 3 to 5 refers to the suspension 10 provided there, which includes vertical profiles 16 and adjustable rails 17 for optimal positioning.

[0052] The Figure 8 and 9 show a non-inventional example of a fan module, each in schematic view, namely Figure 8 from the suction side and Figure 9 from the pressure side. The fan module 24 has no housing and is designed for use alone or with other fan modules connected in parallel within a flow channel. It is a built-in module for a flow channel not shown in the two figures. Otherwise, the same specifications apply as for the previously described embodiments of the arrangement in a housing 2.

[0053] In the Figure 8 and 9 In the example shown, the backflow blocker 6 reduces the effective flow cross-section in the flow channel, instead of in the housing 2, as described above. Otherwise, the same explanations apply as before.

[0054] Here too, a suspension 10 made of round material is provided. This measure minimizes losses. The backflow blocker 6 is made of sheet metal and is attached to the round material or to the struts 10 of the fan suspension 10 by clipping it on.

[0055] Advantageously, a backflow preventer 6 with its fastening means is designed such that it can be attached to a suspension 10 of a fan module 24 without a housing as well as to a suspension of a fan module 24 with a housing 2, for example according to Figure 1 , can be attached. This allows identical backflow preventers 6 to be used for both types of fan modules.

[0056] The in the Figures 8 and 9The fan module 24 shown can be installed in an air conditioning unit with an axial flow channel, which makes the effect of the backflow blocker 6 particularly effective, since a system is created which, from a fluid dynamics perspective, is similar to the embodiment shown in the Figure 1 and 2 is comparable. The backflow blocker 6 is advantageously designed such that it can be mounted both on a suspension 10 according to this figure and on a suspension 10 according to the Figure 1 and 2It can be clipped on. The backflow preventer 6 is also optionally attachable, should it be required. If the backflow preventer 6 is not desired, it can be removed or omitted from the outset. It can definitely be retrofitted to fans already installed in air conditioning units or similar systems. The same principle can also be implemented with differently designed mountings, for example, based on a flat material construction according to the Figures 3 to 6 .

[0057] Figure 10 The fan module shows the Figure 8 and 9 from the side, where the suspension point 10 is particularly clearly visible.

[0058] Figure 11 shows the object from the Figures 8 , 9 and 10 in a top view from the pressure side, where the backflow blocker 6 can be seen at the front.

[0059] Figure 12Figure 1 shows a schematic view of a further embodiment of a fan module according to the invention, wherein the fan 1 is arranged in a housing 2.

[0060] On the pressure side, a sound absorber 20 consisting of perforated sheet metal is arranged, which is attached to the in Figure 12 connects to the non-shown backflow blocker and extends to the pressure-side edge of housing 2.

[0061] The sound absorber 20 consists of perforated sheet metal, whereby a sound-absorbing material can be used in the inner, central area 25 surrounded by the perforated sheet metal. It is also conceivable to manufacture the sound absorber 20 entirely from a dimensionally stable sound-absorbing material.

[0062] Figure 13 The fan module shows Figure 12In a top view from the pressure side, the perforated sound absorber 20 is clearly visible, especially in that it connects to the backflow blocker 6 in the same shape. The suspension 10 with round struts 11 is also visible.

[0063] Figure 14 The fan module shows the Figure 12 and 13 View from the side with the side panel removed. Here too, it is clearly visible that the sound absorber 20 connects directly to the backflow blocker 6, with both components being attached and positioned together via the suspension 10. In Figure 14 It is clearly visible that the backflow blocker 6 is attached to the struts 11 of the suspension 10 by means of a simple clip connection 26. The sound absorber 20 acts on the airflow from its outer side.

[0064] Here too, the axial position of the suspension 10 can be adjusted and adapted to different fans 1. A pressure sensing device 22 is provided at the inlet nozzle 23, which can be used to measure the volume flow rate during operation of the fan 1.

[0065] In the Figures 12 to 14 In the illustrated embodiment, the sound absorber 20 has the shape of a truncated pyramid. This creates widening flow channels 15* between the side walls 4 and the sound absorber 20, or rather its wall 19, acting as a diffuser to convert dynamic energy into pressure energy. This also leads to an increase in efficiency, provided that both the fan 1 and the backflow preventer 6, including the sound absorber 20, are optimally positioned.

[0066] Especially with other housing cross-sections, expanding flow channels 15* can also be realized by means of sound absorbers that have a shape different from the truncated pyramid, for example the shape of a truncated cone.

[0067] The sound absorber 20 can also have the shape of a cuboid, so that no diffusers are formed. In any case, the sound power radiated into a duct system can be reduced by using the sound absorber 20. The outer, square flow path of the housing 2 extends from the backflow blocker 6 in the axial direction over the entire effective area of ​​the sound absorber 20. It is also conceivable that the sound absorber 20 extends out of the housing 2 into a flow channel, in which case, when installed, for example in an air conditioning unit, it is surrounded by channel walls similar to the side walls 4 of the housing 2, thus enabling the sound absorber 20 to exert its effect.

[0068] The outer walls 4 of the housing 2 can also be designed as sound absorbers. This is possible, for example, by using panels made of sound-absorbing material as the outer walls 4. It is also possible to manufacture the outer walls 4 from perforated sheet metal and to attach a sound-absorbing material outside the airflow path. Space is available for this in the radial direction (perpendicular to the side wall 4), provided by the height of the frame structure 3 perpendicular to the housing side wall 4, as is well illustrated, for example, in Fig. 1 can be seen.

[0069] Fig. 15Figure 1 shows another embodiment of a fan module 24 with a backflow preventer 6. In this embodiment, a pressure-side touch guard 27 in the form of a protective grille is integrated into the fan module 24. Pressure-side touch guards are necessary if the outflow side of a fan module 24 can be accessed during fan operation. Since the backflow preventer 6 protects the inner, near-axis area from contact with the fan, the additional touch guard 27 can be limited to the areas of the annular duct 15, which contributes to material and weight savings. Because the distance between the touch guard 27 and rotating parts of the fan 1 in the area of ​​the pressure-side outlet of the annular duct 15 is relatively large, large mesh sizes can be selected for the grille, which is advantageous for efficiency and noise reduction.The touch guard 27 can be designed in various ways, such as a stamped sheet metal part, a mesh grid construction, or a wire ring grid construction. It can be attached to the housing 2, the backflow preventer 6, or both, optionally by screws, rivets, clips, snap hooks, or the like. Otherwise, this embodiment is comparable to the one described, for example, in [reference]. Fig. 1 .

[0070] In Fig. 16 is an advantageous arrangement of four non-inventive fan modules 24 according to the Figures 8 to 11The diagram shows fan modules 24 without housings, arranged side by side in parallel. This arrangement could, for example, be used in a flow channel that surrounds the entire assembly. A special feature of this arrangement is that there are no side walls between adjacent backflow preventers 6. Instead of annular channels 15 as in fan modules with housings, flow channels 15** are formed between adjacent backflow preventers. In this arrangement, the backflow preventers 6 also provide comparable advantages as in embodiments with housings. In central, axially close areas behind the fans 1, backflow is reduced or prevented, efficiency is increased, and noise emissions are reduced.The compactness of the arrangement is achieved by the small lateral spacing of the fan modules 24, which forces axial airflow and makes the use of backflow preventers 6 advantageous. The use of backflow preventers 6 is particularly advantageous for adjacent fan modules 24 without housings when the center-to-center distance of adjacent fans 1 is less than 1.6 x D, where D is the largest diameter of a fan blade of the respective fans 1.

[0071] In Fig. 17Finally, a further, non-inventive example of a fan module 24 with housing 2 and backflow preventer 6 is shown. In this example, the backflow preventer 6 is designed as a load-bearing component and integrated into the fan suspension; that is, the fan suspension 10 and the backflow preventer 6 are the same sheet metal part. In this respect, the suspension 10 assumes a fluid-mechanically positive function. The fan is connected via its motor, similarly to the previous example. Fig. 3The motor is attached to the supporting backflow preventer 6, 10, with the pressure-side end 9 of the motor protruding through a recess 8 in the supporting backflow preventer 6, 10. The advantage of this approach is that fewer parts are required for the construction, since the functions of the backflow preventer 6 and the suspension 10 are performed by the same component. However, a disadvantage is that the backflow preventer 6 must be made of a thick sheet metal to fulfill its supporting function. For structural reasons, this would not actually be necessary across the entire dimensions of the backflow preventer 6.

[0072] Hybrid designs are also conceivable, in which a load-bearing part of the backflow preventer 6 is made of thick sheet metal, while non-load-bearing parts are made of thinner sheet metal. However, this again leads to a larger number of parts.

[0073] Regarding further advantageous embodiments of the teaching according to the invention, reference is made to the general part of the description and to the attached claims in order to avoid repetition.

[0074] Finally, it should be expressly pointed out that the exemplary embodiments of the teaching described above serve only to discuss the claimed teaching, but do not limit it to these exemplary embodiments. Reference symbol list

[0075] 1 Fan, radial fan 2 Housing 3 Frame structure 4 Side panel 5 Nozzle plate 6 Backflow preventer 7 Frame (of the backflow preventer) 8 Recess (of the backflow preventer) 9 Pressure-side end of the fan motor 10 Suspension 11 Struts 12 Angle bracket 13 Further recess in the backflow preventer 14 Electronics / control area of ​​the fan 15 Ring channel 15* Diffuser-like expanding ring channel 15** Flow channel between adjacent fan modules or backflow preventers 16 Vertical profile of the suspension 17 Adjustment rail 18 Screw 19 Wall 20 Sound absorber 21 Not assigned 22 Pressure sensing device 23 Inlet nozzle 24 Fan module 25 Area for sound-absorbing material 26 Clip connection 27 Touch guard Touch protection grille

Claims

1. A fan module comprising at least one fan (1) arranged in a housing (2), an air flow of the fan being conveyed axially through the housing, a mounting (10) for fastening the fan to the housing (2), and optionally a nozzle plate (5), a device for reducing or suppressing a backflow of the outgoing air, the device being configured as a mechanical backflow blocker (6), which is arranged as a flat box, the largest active surface of which extends transversely or orthogonally to the flow direction, approximately centrally in the flow path and blocks part of the flow cross section, such that an annular duct (15) remains as an air passage between the side walls (4) of the housing (2) and the side walls of the backflow blocker (6), the backflow blocker (6) having an axial height that is greater than 5% of the width of the housing in the region of the annular duct (15) and is no greater than 20% of the axial installation height of the fan module (24), characterized in that the backflow blocker (6) does not have a supporting function and uses the mounting (10) of the fan (1), the backflow blocker (6) being clipped to, snapped into, or clamped to the mounting (10).

2. The fan module according to claim 1, characterized in that, when viewed in the axial direction, the outer contour or cross-sectional shape of the backflow blocker (6) is substantially identical or similar to the inner contour or cross-sectional shape of the housing (2).

3. The fan module according to claim 1 or 2, characterized in that the inner contour of the housing (2) is rectangular, in particular square, in cross section when viewed in the axial direction, and in that the backflow blocker (6) is accordingly rectangular or square in cross section when viewed in the axial direction, or in that the inner contour of the housing (2) is round in cross section when viewed in the axial direction and in that the backflow blocker (6) is accordingly round in cross section when viewed in the axial direction.

4. The fan module according to any of claims 1 to 5, characterized in that the backflow blocker (6) has a preferably central cut-out (8) or passage, into or through which a discharge-side region of a motor of the fan (1) protrudes, and / or in that the backflow blocker (6) reduces the effective flow cross section by 40% to 70%, preferably by approximately 55%, and / or in that the backflow blocker (6) is produced as a sound-absorbing component, and is preferably completely made of sound-absorbing material.

5. The fan module according to any of claims 1 to 4, characterized in that the mounting (10) consists of round stock or flat stock, the mounting (10) and thus the backflow blocker (6) being able to have an adjustable position in the housing (1), in particular being able to be adjusted along the mounting (10) axially toward or away from the nozzle plate (5).

6. The fan module according to any of claims 1 to 5, characterized in that the backflow blocker (6) is made of sheet metal or plastics material, in particular surface-structured and / or foamed plastics material.

7. An assembly comprising at least one or more fan modules (24) according to any of claims 1 to 6 in a flow duct or a comparable flow-based system, wherein the flow is conveyed in the axial direction downstream of the fan module(s) (24).

8. The assembly according to claim 7, characterized in that the distance of a wall of a flow duct or a side wall (4) of a housing (2) from a fan axis is less than 0.8 times the largest diameter of an impeller blade of the fan (1) in question.

9. The assembly according to claim 7 or 8, characterized in that at least two fan modules (24) are arranged next to one another.

10. The assembly according to any of claims 7 to 9, characterized in that two adjacent fan modules (24) are in direct contact with one another by their housings (2) and are optionally fastened to one another.

11. The assembly according to any of claims 7 to 10, characterized in that the fans (1) of two adjacent fan modules (24) have an axial distance which is less than or equal to 1.6 times the largest diameter of an impeller blade of a fan (1) in question.

12. The assembly according to any of claims 7 to 11, characterized in that a heat exchanger is arranged downstream of the backflow blocker (6) on the discharge side.