Fan and fan intake grille

Abstract

To provide a fan capable of reducing the noise associated with an unstable flow.SOLUTION: A fan (axial fan, radial fan or diagonal fan) has an impeller and a guide device that is in a flow path upstream of the impeller, preferably in the flow path upstream of an inlet area of an inlet nozzle. The guide device is designed as an intake grid (1) having flat webs (5). The flat webs (5) form a plurality of flow channels resembling grid apertures (6).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention relates to a fan (axial, radial or mixed flow fan) having an impeller and a guide device in the flow passage upstream of the impeller, preferably upstream of the suction area of ​​the suction nozzle, in which the guide device is designed as an intake grid with a plurality of flat webs which form a plurality of flow passages resembling grid openings. Furthermore, the invention relates to a particular guide device designed as an intake grille with a number of flat webs. [Background technology]

[0002] For example, a typical fan with a guide device on the intake side is known from DE 10 200 04 133 A1. The guide device provided in Patent Document 1 is useful for smoothing the flow and reducing noise. This known guiding device generates a pre-swirl in the direction of rotation of the impeller. It is important to note that improving acoustics generally comes with an associated decrease in aerodynamic performance and efficiency. The guide device provided in US Pat. No. 5,649,499 is also very expensive to manufacture.

[0003] So-called guide wheels, which are used to improve aerodynamic performance and / or efficiency, are also known in practice. However, these guide wheels not only have an acoustic disadvantage and are complex to design, but also complicate installation into the fan product. Typically, the guide wheel is installed upstream of the fan impeller in a cylindrical installation space of approximately the same diameter as the fan impeller, so that the throughflow area is not significantly increased. Therefore, in the flow area of ​​these guide wheels, the air flow velocity is relatively high, which has particular acoustic drawbacks. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 03 / 054395(A1) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention is based on the following technical problems.

[0006] Fans often produce a lot of noise when the inflow is unstable. In many fan applications, for example residential ventilation controls (CRV), there is typically a desire for compact design, which inevitably results in unstable inlet conditions. This results in noise, which is often the dominant sound source and is usually low frequency noise. Noise reduction measures for this low frequency noise are essential in ventilation systems.

[0007] It has also been shown that noise associated with unsteady flow can be significantly reduced by using a rectifier. However, such a flow straightener causes a substantial pressure drop that is not insignificant, and also requires a large installation space. It is therefore an object of the present invention to provide designs and improvements to such fans to reduce the noise associated with unsteady flows. The fan should be compact and create only a small pressure drop. Furthermore, the intake guide device, in particular the intake grille and / or the guide adjustment device, should be provided in such a way that it can be manufactured by injection molding of plastic using economical tooling, while meeting the above requirements. It must be dimensionally stable and advantageously take over the function of the contact protection grid on the intake side. [Means for solving the problem]

[0008] The above mentioned object is achieved by the fan according to the invention by combining the features recited in the features of independent claims 1, 2 and 3. The above-mentioned object of the inlet grille of the present invention is achieved by the features of claim 12, which is based on the claim relating to the fan.

[0009] In a first variant as claimed in claim 1, a plurality of webs extend between two branches or between each one of the branches and the border area. Preferably, there are three webs in each branch. These features preferably create flow paths that resemble a grid of openings, which are suitable for reducing noise when the flow is unstable.

[0010] The independent claim 2 achieves the above object by providing a flow channel having a honeycomb cross section. This design also provides particularly good stability.

[0011] Another independent claim 3 relates to an alternative option in which the intake grid has a cage-shaped profile, in this embodiment the cage-shaped profile is based on the outer and / or inner envelope of the intake grid.

[0012] The same applies to the embodiment of the intake grille itself, as defined in the other independent claim 12, which refers to the claim relating to this fan.

[0013] The independent claims are based on the basic idea of ​​providing an intake or inlet grid upstream of the suction nozzle of the fan in order to reduce the noise generated in the event of flow instabilities in the operation of the fan. The intake grid is defined by flat webs, which are arranged relative to one another to form flow passages that resemble grid openings. By skillfully combining the webs that form the branches and nodes, advantageous geometries can be achieved (for example, honeycomb cross sections of the channels). The term "honeycomb" should be understood in the broadest sense and includes polygonal shapes such as square, pentagonal or hexagonal structures as well as lattice-like openings with a cross section having more angles.

[0014] With the aforementioned flow paths resembling grid openings, it is advantageous if the intake grid has a cage-type profile. The term profile may refer to either the outer or inner envelope of the intake grille.

[0015] The intake grid as described above satisfies the requirement for radial intake flow in the region near the nozzle plate. These flow paths have the advantage of minimizing pressure loss. The contour of the outer envelope of the cage mold is also advantageous for ease of demolding in injection molding techniques used with plastic parts. Furthermore, compact gratings with respective properties can also be produced in this way.

[0016] It is particularly advantageous if the profile of the outer envelope of the cage is continuous and curved. The grid web should be designed to be as thin as possible, for example, with a web thickness in the range of 0.25 mm to 1 mm. In the throughflow direction, the web should be at least 5 mm deep (hence the term "flat web" used in the claims).

[0017] It is further advantageous if the grid-like webs form an unstructured grid, with honeycomb grid-like openings interlocking with one another. As mentioned above, the grid of openings may be polygonal and may interlock with one another. This allows for minimal flow disturbance by the grid webs, resulting in negligible losses in pressure and efficiency, provided a certain maximum grid width is required to achieve the required noise reduction or to take into account contact protection measures.

[0018] Also, the intake grille extends over the entire area, up to the imaginary extension of the fan axis, i.e. there is no large central opening in the inner area, or even no central opening at all. Such a central opening is unnecessary with the teachings of the present invention. If the intake grille also serves as a contact protection function, it must not have a central opening. Furthermore, it has been found that a central opening does not advantageously function to achieve the goals of noise reduction and grid stability.

[0019] In any case, this special design of the intake grid is particularly advantageous, not only in terms of the flow passages which resemble grid-like openings, but also in terms of the continuously curved outer contour. The unstructured grid can be made using square, pentagonal, or hexagonal honeycomb elements, allowing for different grid widths across the intake grid as desired.

[0020] The inlet grille of the present invention is intended for use in an axial, radial or mixed flow fan and is designed in accordance with the foregoing description.

[0021] Currently, various possibilities exist for designing and improving the present invention. Please refer first to the claims, which refer to claim 1, and then to the drawings, which illustrate embodiments of the inventive air intake grid. Embodiments and improvements relating to the present invention will also be described in conjunction with examples of the present invention with reference to the drawings. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view of an embodiment of the intake grid of the present invention, as viewed from the intake side. FIG. [Figure 1a] 2 is a perspective view of an aperture formed in the web of FIG. 1, showing characteristic dimensions of the web and aperture. [Figure 2] FIG. 2 is a perspective view of the intake grille of FIG. 1 as seen from the outflow side. [Figure 3] 3 is a top view of the intake grid of FIGS. 1 and 2 as viewed axially from the inlet side. FIG. [Figure 4] 4 is a top view of the intake grid of FIGS. 1 to 3 as viewed in the axial direction from the outflow side. FIG. [Figure 5] 5 shows a side view and a cross-sectional view of the intake grid of FIGS. 1 to 4 in a plane passing through an imaginary central axis, showing the characteristic dimensions of the intake grid. [Figure 6] FIG. 10 is a perspective view of another embodiment of the intake grille of the present invention, as viewed from the inlet side. [Figure 7] 7 is a top view of the intake grid of FIG. 6 as viewed in the axial direction from the outflow side. [Figure 8] FIG. 10 is a perspective view of another embodiment of an intake grille, as viewed from the inlet side. [Figure 9] FIG. 9 is a perspective view of the intake grid of FIG. 8 as seen from the outflow side. [Figure 10] 10 is a top view of the intake grid of FIGS. 8 and 9, viewed axially from the inlet side. FIG. [Figure 11] 11A and 11B are side and cross-sectional views of the intake grid of FIGS. 8 to 10 taken along a plane passing through an imaginary central axis, showing the characteristic dimensions of the intake grid. [Figure 12] 1A and 1B are side and cross-sectional views of an intake grille of the present invention having curved webs, taken along a plane passing through an imaginary central axis. [Figure 13] FIG. 10 is a perspective view from the inlet side of another embodiment of the air intake grille of the present invention having a closed central injection area. [Figure 14] 14 is a top view of the intake grid of FIG. 13 as viewed in the axial direction from the inlet side. [Figure 15] FIG. 15 is a side view of the intake grille of FIGS. 13 and 14. [Figure 16] 16A and 16B are side and cross-sectional views of the intake grille of FIGS. 13 to 15 taken along a plane passing through an imaginary central axis; [Figure 17]17A and 17B are a perspective view and a cross-sectional view taken along a plane passing through an imaginary central axis of a fan having a motor, an impeller, an intake nozzle, a nozzle plate, and the intake grille of FIGS. 13 to 16, as seen from the inlet side. DETAILED DESCRIPTION OF THE INVENTION

[0023] FIG. 1 shows a perspective view of an embodiment of an intake grille 1 seen from the front, i.e. from the inlet side. As shown in FIG. 17, the intake grille 1 is mounted upstream of the suction nozzle 2 of the fan so that its central axis corresponds approximately to the rotation axis of the fan. During fan operation, air flows first through the intake grille 1 into the suction nozzle 2 and then through the fan impeller, which is driven by the motor 4, increasing the overall pressure. The intake grille 1 smooths the incoming airflow, thereby reducing noise generated by the impeller.

[0024] The air intake grid 1 comprises a plurality of webs 5 that define flow passages 6 formed in the grid openings. During operation of the fan, air flows through the channels 6 formed in the grid openings. The flow area of ​​the airflow carried by the fan is larger in the area upstream of the suction nozzle 2 than inside the suction nozzle 2, so the flow speed of the incoming air is slower in the area upstream of the suction nozzle 2 than inside the suction nozzle 2. The intake grid 1 is used in such areas where the flow velocity is low. That is, the flow velocity in the intake grid 1 is slower than the flow velocity in the suction nozzle 2 . This minimizes flow losses and noise generated at the intake grid 1.

[0025] However, the inflow into the region upstream of the suction nozzle 2 is not smooth, ie not parallel to the central axis. Therefore, there is a great advantage in not designing the intake grid 1 to have a perfectly smooth contour. This contour may also be formed by the outer envelope 7 and / or the inner envelope 8 (FIG. 2) of the intake grille 1. The outer envelope surface 7 is defined by the entire outer end surface 7a of the inflow end of the web 5, and the inner envelope surface 8 is defined by the entire inner end surface 8a of the outflow end of the web 5 (see Figure 1a for the outer end surface 7a and the inner end surface 8a). Furthermore, the outer envelope surface 7 and the inner envelope surface 8 are defined in the flow region of the flow channel 6 by complementing the outer end surface 7a and the inner end surface 8a with an imaginary continuous plane or an imaginary continuous curved surface.

[0026] FIG. 1a is a detailed enlarged view of an area of ​​the intake grille 1 of FIG. The web 5 has a significant depth t(9) in the direction of throughflow, ranging from about 6 mm to about 20 mm. For this reason, the web 5 is also called a "flat" web. Furthermore, the flow channels 6 formed in the grid-like openings are essentially characterized by an opening width w(12), which is defined, for example, as the radius of the largest sphere that can fit inside the flow channels 6 formed in the grid-like openings. A small opening width w(12) is advantageous for achieving good acoustics, for example, the opening width w(12) is no more than two to three times the web depth t(9) in most of the channels 6 formed in the grid openings of the intake grid 1. Furthermore, since the intake grille 1 in the embodiment of FIG. 1 is also a contact protection device, there are standard and regulatory requirements regarding the opening width w(12) as a function of the shape of the flow path 6 formed in the grille-like opening and the distance from the rotating part of the fan to the flow path formed in the grille-like opening 6, and the opening width w(12) must comply with these requirements. Therefore, there is an upper limit to the size of the opening width w(12).

[0027] In order to reduce pressure and efficiency losses, it is advantageous to reduce the obstructions in the through-flow area of ​​the grid-like webs 5 as much as possible. This can be achieved by having a thin web 5 (web thickness d(10) ≦2 mm [≦1 mm]) and / or by minimizing the overall length of the web 5. The total length of the web 5 is the sum of all the web lengths l (11) of the intake grille 1, which are determined based on the center line 13. The center line 13 lies on the outer envelope surface 7 and / or the inner envelope surface 8 . Under the conditions described above for the maximum grid width w(12), the adoption of an "unstructured" grid design with honeycomb openings as in this embodiment provides a significant advantage in the total required web length.

[0028] FIG. 2 shows a perspective view of the intake grille 1 of FIG. 1 as seen from the outflow side. The intake grille 1 has an attachment area 18 in its outer area, which serves to attach the intake grille 1 to the suction nozzle 2 or to the nozzle plate 32 (FIG. 17). For the design of the attachment area 18, various options are possible. Possible fastening means include screws, rivets, snap fit hooks, bayonet closures, adhesive bonds, interlocks, hook and loop fasteners, and the like. In this embodiment, each of the four attachment regions 18 is provided with a screw hole.

[0029] The cage-shaped profile of the inner envelope 8 of the intake grille 1 can be best seen in FIG. This profile has a short axial length on the outer periphery, advantageously exceeding 10 mm or 8% of the outer diameter D(20) (FIG. 5), is approximately parallel to the imaginary central axis, and is approximately cylindrical (cylindrical region 34). This cylindrical surface area 34 includes an outer row of openings 19, with two adjacent openings 19 being separated from each other by an outer row of webs 35. The openings 19 in the outer rows are very elongated. In order for the openings 19 in the outer row to ensure contact protection and improve acoustics, the opening width w of these openings 19 (the inner sphere radius, which is essentially defined by the distance between two adjacent webs 35 in the outer row of openings 19) tends to be small compared to the inner sphere radius of the channels 6 formed in the other openings. In the inner region near the imaginary central axis, the contour is flat or planar (flat region 33) and is approximately perpendicular to the imaginary central axis. In this embodiment, the transition from the flat region 33 to the cylindrical region 34 is made by a short transition region 24 having a curvature. In this embodiment, the outer envelope surface 7 and the inner envelope surface 8 are substantially parallel to each other. The flat region 33, the cylindrical region 34, and the transition region 24 can be classified based on the outer envelope surface 7 and / or the inner envelope surface 8, respectively.

[0030] FIG. 3 is an axial top view of the intake grid 1 of FIGS. 1 and 2 as viewed from the front (from the inlet side). Such an intake grille 1 is advantageously manufactured by injection molding of plastic. Furthermore, in order to minimize mold complexity, it is also advantageous to select the same direction as the line of sight in FIG. 3 as the mold release direction for the injection mold. In that case, one mold part moves relative to the intake grille 1 towards the viewer in FIG. Advantageously, this mold part is on the nozzle side of the mold, with the other mold part moving away from the viewer in FIG. For ease of manufacture, it is advantageous if the injection mold does not have other slide valves.

[0031] The attachment area 18 is designed integrally with the grid-like web 5, so that it can be released from the injection mold without undercuts in a sliding direction parallel to the imaginary central axis (corresponding to the line of sight of this figure). It can be seen that some of the grid webs 5 are not parallel to the imaginary central axis (= line of sight), but instead their orientation is optimized for the intake conditions. The web 5 may also have a curvature to optimally guide the flow. For example, the web 29 is an axially oriented web, ie, the web 29 is parallel to the imaginary central axis (line of sight and sliding direction), which facilitates demolding. The axially oriented web 29 has a release angle. However, since all webs 5 are optimized in the machine direction, there are also webs 30, 30a that are not axially oriented. The two radially outermost rows of the grid-like webs 5, which are arranged approximately in the circumferential direction, are located in the transition region 24 of the outer envelope surface 7 or the inner envelope surface 8, so that there are slight or no undercut regions. That is, it is slightly obscured or not obscured at all when viewed axially. In the embodiment shown here, for example, at the junction between web 5a of the radially outermost row of webs 5 and web 5b of the second outermost row of webs 5, there is an area where these two webs slightly overlap in the line of sight, and a small undercut area 17 exists. With suitable relatively elastic materials, even a simple open / close mold can be produced with only slight undercuts during axial demolding. This allows for the simple and economical creation of highly fluidly optimized profiles. Additionally, there is a small undercut area in the divergence region 15 between the two non-axially oriented webs 30 and 30a. This is because the positive or negative signs of the x components of the normal vectors of those web surfaces are different. This small undercut, with the appropriate material, allows for easy demolding from a simple open / close mold.

[0032] In this embodiment, the opening in the inner region near the imaginary central axis is smaller than the opening in the outer region away from the imaginary central axis. The size of the opening, i.e. the opening width w (12, see Figure 2), is optimized with respect to the requirements for regulatory compliance of contact protection and dimensions for acoustic improvement and / or flow smoothing. The distribution of the apertures is optimized using a special algorithm. The shape of the opening (referring to either the outer envelope surface 7 or the inner envelope surface 8) may vary, including, but not limited to, a square, an irregular square, a regular pentagon, an irregular pentagon, a regular hexagon, and an irregular hexagon. The area of ​​each opening (see either the outer envelope surface 7 or the inner envelope surface 8) roughly represents the area where the imaginary center point (on the envelope surface) of that opening is closer than the imaginary center points of the other openings. As a result, the structure of the intake grille 1 is characterized in that most branching regions 15 have exactly three webs 5, and there are far fewer branching regions with four webs 5 together. Furthermore, in the boundary region, the openings are formed as if they were cut off from the outside, but there are no openings that have a relatively small through-flow area that is less than 50% of the through-flow area of ​​the adjacent opening.

[0033] FIG. 4 shows a top view of the intake grille 1 of FIGS. 1 to 3 as viewed axially from the rear (outlet side). The axially oriented outer row of webs 35 has one free end 14 . Thus, the web 35 can be demolded using a slide valve mold that moves in the direction of the outflow side (towards the viewer in FIG. 4) as the mold opens. The lack of connection at the free ends 14 of the outer webs 35 creates a disadvantage in terms of strength and dimensional stability, but this can be compensated for by using higher quality material or by increasing the wall thickness d(10).

[0034] The intake grille 1 of this embodiment is designed to have four identical segments. This is particularly advantageous in the construction of parts and molds required for manufacturing. This is because the number of channels 6 that make up the grid openings, which are different in shape, is thereby reduced to one-fourth (four being the number of identical segments). This segmentation eliminates the fact that the flow pattern is independent for each arrangement x (quadrant) of the intake grid 1 within the assembly. A different number of segment configurations are possible. The segment settings may differ in minor respects, for example with respect to attachment means where the number of attachment means does not correspond to the number of segments, or in some circumstances in the inner region near the imaginary central axis where segment setting is difficult. In particular, when the outer diameter is large, the segments can be advantageously configured so that the intake grille 1 can be assembled from multiple injection-molded segments, for example by clipping, snapping, screwing, gluing or fastening to a nozzle plate or the like. In this multi-part approach, it is also possible to produce different separate central parts in addition to the actual identical segments, but these different parts require separate injection moulds. However, this central portion may be of simple design, in particular of planar, ie flat, design.

[0035] In the embodiment shown here, there is a central branch point 16 where four (= the number of segments in the embodiment) webs 5 meet on the central axis.

[0036] FIG. 5 shows a side view and a cross-sectional view of the intake grille 1 of FIGS. 1 to 4 in a plane passing through the imaginary central axis. Here, the shape of the cage-shaped profile of the outer envelope surface 7 on the inlet side and / or the inner envelope surface 8 on the outlet side can be clearly seen. The outer envelope 7 has an outer diameter D(20) (also called the diameter D(20) of the intake grille 1), but the diameter of the attachment area 18 is not taken into account here. In this embodiment, the outer envelope surface 7 and the inner envelope surface 8 are substantially parallel to each other. The distance of the outer envelope surface 7 and the inner envelope surface 8 from each other is between 6 mm and 18 mm, or about 3% to about 10% of the outer diameter D (20) of the intake grille 1. The cage-shaped profile extends in an upper and lower region close to the mounting height for a distance parallel to the axial direction (cylindrical surface region 34). The flat region 33 transitions continuously and curves at the transition region 24 on the right side (inlet side) of the figure. The transition region 24 is radially short, being less than 12.5% ​​of the outer diameter D(20). The flat region 33 has a diameter DE(21) ​​which is advantageously relatively large, advantageously at least 75% of the value of the outer diameter D(20). The intake grille 1 has an axial design height H (22), and the cylindrical area 34 on the outer envelope 7 has an axial height HZ (23). Advantageously, the axial height HZ (23) is greater than 6% of the outer diameter D (20).

[0037] The cage-shaped contour of the intake grid 1 and / or its outer envelope 7, inner envelope 8 is well adjusted with respect to the flow conditions. Air entering radially from the nozzle plate 32 is expected to enter the cylindrical region 34 . This allows the outer envelope surface 7 and the inner envelope surface 8 to be traversed over a short distance, minimizing flow losses due to the cylindrical shape of the grid 1 in this region. In the axial direction, it is expected to enter a flat, i.e., flat region 33, then traverse the outer envelope 7, the inner envelope 8 and pass through the intake grid 1 for a short distance. The small space requirement for the intake grille 1 is advantageous because the transition area 24 can be designed small with a low design height H (22). Advantageously, the axial design height H(22) is less than or equal to 25% of the outer diameter D(20).

[0038] Furthermore, the target web orientation is well understood and is not always exactly perpendicular to the envelope, but is optimally adapted and in some cases deviates significantly from the correct inflow direction. In this embodiment, the web 5 is not curved in the throughflow direction, although this is highly envisioned in other embodiments. In the radially outer webs 35, the outer ends 14 are open, i.e., they are not connected to one another (except at the attachment region 18).

[0039] FIG. 6 shows a perspective view of another embodiment of the intake grille 1 as seen from the front (inlet side). Unlike the embodiment according to FIGS. 1 to 5, the outer ends 14 of the webs 35 of the outer rows are connected by an outer connecting ring 25 . This increases the dimensional stability of the outer web 35 when using soft or elastic materials and may be advantageous with regard to compliance with touch protection requirements. Additionally, the outer connecting ring 25 may be beneficial to the filling performance of the injection mold. The outer connecting ring 25 is connected to the web 35 by an attachment 27 . This attachment 27 has a large curvature shape with a radius of curvature exceeding 3 mm and is designed as an extension region of the outer web 35 . The attachment area 18 is integrated into the outer connecting ring 25 .

[0040] In this embodiment, the outer connecting ring 25 lies in a plane representing the plane of screw fixing to the nozzle 2 and / or nozzle plate 32 . In other embodiments, the outer connecting ring 25 may be axially offset from the threaded fixing surface so as to be away from the attachment area 18 . This creates a space between the nozzle 2 and nozzle plate 32 and the outer connecting ring 25 in the mounted state. Such space may be necessary for any screw heads and may be used for the threaded connection between the nozzle 2 and the nozzle plate 32 or for locating a pressure demolding device. If the outer connecting ring 25 is axially offset from the screw fixing surface in some areas, some or all of the webs 35 of the outer row may or may not protrude axially towards the nozzle 2 and / or nozzle plate 32. Additional webs may be attached in the area between the connecting web and the screw fixing surface. In other embodiments, it is also conceivable that the outer connecting ring 25 is interrupted in some areas, so that individual outer ribs 35 with open outer ends 14 may also be present. These outer ribs 35 with open outer ends 14 may also be short, in which case the outer ends 14 are located away from the screw fixing surface. This configuration may also be useful in creating space for screw heads, pressure release devices, etc. between the screw fixing surface and the intake grille 1 in the installed state.

[0041] FIG. 7 shows a top view of the intake grid 1 of FIG. 6 as viewed from the rear (outlet side) in the axial direction. In this view, it can be seen that the outer connecting ring 25 is positioned completely radially outward of all webs 5 (except for the axially oriented webs 35 of the outer row having attachments 27 to the outer connecting ring 25). This is particularly advantageous as it allows the intake grille 1 to be easily released from a simple open-close injection mould. FIG. 7 shows, by way of example, four identical openings 26 of an intake grille 1 consisting of four identical segments. Such a segmented configuration significantly reduces the number of parts for the different openings, thus reducing the costs of building the intake grille 1 and the respective injection moulds.

[0042] FIG. 8 shows a perspective view of the intake grille 1 as seen from the front (inlet side). The openings 6 and webs 5 are not arranged in a honeycomb manner, and the arrangement is unstructured. Instead, there are radially and circumferentially extending webs 5 . The four radially extending webs 5 meet at a central branch point 16 in the central shaft region. The number of webs 5 that meet in each branch region 15 is typically four. The intake grille 1 has a cage-shaped profile of the outer envelope 7 . In this embodiment, no transition region is formed between the flat region 33 and the cylindrical region 34, but instead there is a "knee" separating or connecting these two regions. A design similar to that of FIG. 8, with a stable tangential transition region 24 similar to that of the embodiment of FIGS. 1-5, is also contemplated. The mounting area 18 of the intake grille 1 according to FIG. 8 is mounted between two adjacent webs 35 of the outer row of the intake grille 1 in the circumferential direction.

[0043] The webs 5a and 5b shown as examples have large undercut areas 17 relative to the direction of release parallel to the imaginary central axis. Due to this large undercut area 17, a simple open / close injection mold release parallel to the axial direction cannot be envisaged. It is conceivable to use a star-shaped radially outward releasing slide valve which forms a part corresponding to the cylindrical surface region 34 of the intake grille 1 for releasing.

[0044] FIG. 9 shows a perspective view of the intake grille 1 of FIG. 8 as seen from the rear (outlet side). The cage-shaped profile of the inner envelope 8 can now be better seen.

[0045] FIG. 10 shows an axial top view of the intake grid 1 of FIGS. 8 and 9 as seen from the front (as seen from the inlet side). As an example, four identical openings 26 are shown in a four-part segment setup.

[0046] FIG. 11 shows a side view and a cross-sectional view of the intake grille 1 of FIGS. 8 to 10 in a plane passing through the imaginary central axis. In this intake grille 1, the diameter D(20) of the intake grille 1 corresponds to the diameter DE(21) ​​of the flat, ie flat region 33, since no transition region is formed. The axial design height H (22) of the intake grille 1 is slightly higher than the axial height HZ (23) of the cylindrical part, since the mounting area 18 extends axially beyond the intake grille 1 to the right (towards the screw fixing surface). This means that in the installed state, beyond the installation area 18, there is a small distance between the nozzles 2 and / or nozzle plate 32 and the intake grille 1 and / or the webs 35 of the outer rows. This distance provides, for example, space for the head of the screw connecting the nozzle 2 and the nozzle plate 32 or space for a pressure demolding device within the radius of the suction nozzle 2 . Similar designs in which spaces are formed between at least some of the outer lattice webs 35 and / or outer connecting rings 25 and the nozzles 2 and / or nozzle plates 32 are also contemplated for the embodiments having similar unstructured lattices in Figures 1 to 7 and 12 to 16. Similarly, in embodiments with an unstructured grid, it is conceivable that no transition region is formed between the cylindrical region 34 and the flat, i.e., planar region 33 of the intake grid 1, but instead they adjoin each other at a bend.

[0047] FIG. 12 shows a side view and a cross-sectional view of another embodiment of an intake grid 1 of the present invention, taken along a plane passing through the imaginary central axis. The web 5 in this embodiment is partially curved as seen in cross section. It is therefore possible to adapt well to the incoming flow of the intake grid 1 and / or web 5 . Furthermore, the web 5 on the inflow side (outer envelope surface 7) has a surface angle that is favorable for flow, which is advantageous during mold release. Furthermore, due to the curved web 5, the inflow losses can be reduced to a predetermined target when required. Any curvature is possible, in terms of direction and magnitude. The curved web 5 may also be an axially oriented web at the same time. In this manner, the webs 35 of the outer rows may also be curved and axially oriented, for example.

[0048] FIG. 13 shows a perspective view from the front (inlet side) of another embodiment of the air intake grille 1 according to the invention. Since the intake grille 1 is of unstructured construction, in most cases three webs 5 meet in the branching region 15 . An outer connecting ring 25 is formed which connects the outer rows of webs 35 together. The attachment 27 of the outer web 35 to the outer connecting ring 25 is designed with a rounded shape, with a relatively large radius of curvature in the extension of the web. The attachments 27 advantageously extend radially over the majority of the radial extent of the outer connecting ring 25 (more than half of the area). The four attachment areas 18 are integral with the shape of the outer connecting ring 25 . The outer web 35b, located approximately in the circumferential center of the mounting area 18, has a reduced outer diameter to provide access for threadedly connecting the intake grille 1 to the mounting area 18. These outer webs 35b, which have a reduced outer diameter, extend inward to provide the stability and required cross-section required for the injection molding process (see also the outer row of webs 35b in the area of ​​the attachment area 18 in Figure 16).

[0049] In the embodiment according to FIG. 13, a closed central emission area 28 is provided. In plastic injection molding, molten plastic is injected into the center of this central injection area 28 and distributed onto the web 5 through this disk-shaped area. In this embodiment, the innermost web 5 has an inner edge 31 where the webs 5 meet at the central injection region 28 .

[0050] FIG. 14 shows a top view of the intake grid 1 of FIG. 13 as viewed from the front (from the inlet side) in the axial direction. This embodiment is designed to be completely undercut-free for axial demolding. This makes mold manufacturing much easier and ensures a reliable injection molding process with short cycle times. By way of example, two webs 5a and 5b are shown here which are aligned so that they do not overlap, as can be seen in this axial top view. To achieve this, it is important to closely coordinate the shape of the outer envelope surface 7 and the inner envelope surface 8, the selection of the web depth t (9), and the position and orientation of the web, taking into account compliance with regulations requiring contact protection measures.

[0051] When using axially oriented webs 29, it is important to prevent two non-axially oriented webs 30 from crossing in the branching region 15 in order to prevent undercutting in the region close to the branching region 15, and it is important to ensure that the signs of the x-components (components parallel to the imaginary central axis) of two vectors perpendicular to the wall and directed toward the same opening 6 are different, being positive and negative. As a result, in this embodiment having a bifurcation region 15, often two non-axially oriented webs 30 will meet with one axially oriented web 29, or three axially oriented webs 29 will meet. Combinations other than this one do not occur frequently. The axially oriented web 29 is advantageously designed with a release angle to facilitate release from the injection mold. In an injection mold, both sides of the axially oriented web are formed in the same mold part. Strictly speaking, the characterization "axially oriented" applies to the central surface between the two surfaces of the axially oriented web 29.

[0052] Designing an intake grille with no undercuts at all requires accepting acoustic and efficiency limitations in some circumstances. In some circumstances, it may be wise to accept small undercuts, and simple mold release may still be possible (forced release, rotational movement of mold parts, placement of ejectors in the contoured area of ​​the part, etc.).

[0053] In this embodiment, all webs 5 are designed as axially oriented webs 29 in the radially inner (and outer than a particular region) area. As a result, for inner openings 6 having webs 29 that are only or primarily axially oriented, the mold may be designed so that the mold parting line does not pass diagonally through the opening. In that case, the complete contour of the opening can be introduced into the mold part. This makes the mold easier to manufacture. Furthermore, this configuration ensures that the inflow into the inner region near the imaginary central axis is axial, without significant loss of efficiency or acoustics.

[0054] The embodiment of FIG. 14 is constructed from 12 identical segments, the rotational symmetry of which is only locally broken at four attachment regions 18 . The number of different parts of the flow passage 6 formed in the opening is certainly reduced by the segmentation using a large number of segments. In this embodiment, the intake grid 1 has a total of 312 passages 6, but due to the segmentation, only 26 different passages 6 are designed. An embodiment having eight segments is also particularly advantageous.

[0055] In embodiments having four attachment regions 18, it is advantageous if the number of segments is a multiple of four. In particular, the inventive intake grille 1 can be manufactured in multiple parts with larger outer diameters using a segmented setup.

[0056] FIG. 15 shows a side view of the embodiment of FIGS. The attachment area 27 of the outer web 35 to the outer connecting ring 25 can be clearly seen. The attachment area 27, which is here embodied as curved, may also be embodied in other forms, for example as a chamfer.

[0057] FIG. 16 shows a side view and a cross-sectional view of the embodiment of FIGS. 13 to 15 taken along a plane passing through the imaginary central axis. The webs 5a and 5b described as examples do not overlap in the axial direction. Furthermore, the outer connecting ring 25 does not hide the web 5a when viewed in the axial direction. This is advantageous for a simple design of the injection mould, since undercuts between the webs 5a, 5b and the outer connecting ring 25 should be avoided for axially parallel demolding. For better accessibility, the webs 35 b of the outer row in the region of the mounting area 18 have a smaller outer diameter to accommodate the screws that fasten the intake grille 1 to the suction nozzle 2 or nozzle plate 32 . The diameters of these webs 35b are also at least slightly offset inward to provide a web depth t that is advantageous for strength and the injection molding process.

[0058] The central emission region 28 is best seen in cross section. In the injection molding process, the molten plastic injected into the center of this area can be fully distributed over the web 5 via the inner edge 31 . The inner end 31 here is advantageously curved and / or chamfered between it and the central emission region 28 .

[0059] FIG. 17 shows, by way of example, a schematic representation of a fan having an intake grille 1, suction nozzles 2 attached to a nozzle plate 32, and a fan impeller 3 driven by a motor. In operation, air flows first through the intake grille 1 to the suction nozzle 2 and then through the rotating impeller 3 of the fan, experiencing an overall increase in pressure. The turbulence in the incoming air causes a lot of noise in the fans. The intake grille 1 of the present invention smooths the inflow and reduces noise. The intake grille 1 also functions as a contact protection measure on the intake side. The pressure drop that occurs as the air flows through the intake grille 1 is minimized by the present invention. In this embodiment, a mixed flow fan 3 is shown. The intake grille 1 can be used for radial or axial fans as well.

[0060] For additional embodiments of the present invention, please refer to the general part of the description and the appended claims to avoid repetition.

[0061] Finally, the above-described embodiments of the present invention are merely illustrative of the present invention and are not intended to limit the present invention. [Explanation of symbols]

[0062] 1. Intake grille 2. Suction nozzle 3 Fan impeller 4 Motor 5, 5a, 5b Web 6. Flow path of lattice opening 7. Outer envelope of the inlet side 7a: Outer end face of the web on the inlet side 8 ...Inner envelope surface 8a: Inner end face of the web on the outflow side 9 Web depth t 10 Web thickness d 11 Web length l 12...Aperture width w, inner sphere radius 13. Web centerline 14: Outer edge of web, boundary area 15. Web branching area 16. The central branch of the web 17 Undercut area 18 Mounting area 19. Outer row openings 20 Diameter of the grid D 21 Diameter of the flat, i.e., planar, grating section DE 22 Axial height H of the grating 23 Axial height HZ of the cylindrical area 24 Transition region of the envelope 25 Outer connecting ring 26. Identical opening of segments 27 Connection area attachment 28. Closed central injection area 29 Axially Oriented Web 30, 30a···Axially non-oriented web 31: Inner edge of web (boundary region) 32 Nozzle plate 33 ······Flat, i.e., flat, area of ​​the intake grille 34 Cylindrical area of ​​intake grid 35 Outer row web 35b.........Web of the outer row in the area of ​​the mounting area 18

Claims

1. A fan having an impeller and a guide device mounted upstream of the suction area of ​​a suction nozzle (2), the guiding device is designed as an intake grille (1) with a plurality of flat webs (5), the plurality of flat webs (5) forming a grid of openings with a plurality of channels (6); The grid-like openings at least partially have a honeycomb cross section; the channels (6) are formed by regular and irregular polygons with quadrilateral, pentagonal and / or hexagonal cross sections due to the different contours of the channels (6), 1. A fan comprising: a plurality of flat webs (5) each having a plurality of flat webs (5) arranged in a branching section (15); two different webs (5) not oriented in the axial direction of the imaginary central axis of the intake grid (1) merge with one web (5) oriented in the axial direction of the imaginary central axis of the intake grid (1).

2. 2. The fan according to claim 1, wherein the grid openings in the area near the imaginary central axis are smaller than the grid openings in the area away from the imaginary central axis.

3. A fan having an impeller and a guide device mounted upstream of the suction area of ​​a suction nozzle (2), the guiding device is designed as an intake grille (1) with a plurality of flat webs (5), the plurality of flat webs (5) forming a grid of openings with a plurality of channels (6); the intake grille (1) has a cage-shaped profile consisting of an outer envelope and / or an inner envelope including a cylindrical outer region (34) and a flat region (33) in the vicinity of the imaginary central axis of the intake grille (1); A fan characterized in that, in at least one branch (15) formed by the plurality of flat webs (5), two different webs (5) not oriented in the axial direction of the imaginary central axis merge with one web (5) oriented in the axial direction of the imaginary central axis.

4. 4. A fan according to claim 1, wherein the area without the webs (5), i.e. without the flow passages (6), is formed in the center of the intake grille (1).

5. A fan according to any one of claims 1 to 4, characterized in that the flat webs (5) have a web thickness in the range of 0.25 mm to 2 mm.

6. 6. A fan according to any one of claims 1 to 5, characterized in that the inner area of ​​the contour of the intake grid (1) in the vicinity of the imaginary central axis is plane or very flat and is substantially perpendicular to the imaginary central axis.

7. 4. The fan according to claim 3, wherein an outer boundary area of ​​the contour that forms the inner envelope surface is substantially parallel to the imaginary central axis and forms a substantially imaginary cylindrical surface.

8. the intake grille (1) has fixing means on its outer boundary area, 8. A fan according to any one of claims 1 to 7, characterized in that the fastening means are integral with some of the flat webs (5) and serve for snap-fit ​​and / or press-fitting onto the suction nozzle (2) or nozzle plate (32) of the fan.

9. 9. A fan according to claim 7, wherein a connecting ring (25) is formed on the outer boundary area of ​​the intake grille (1) and includes fastening means for snap-fitting and / or press-fitting to the suction nozzle (2) or nozzle plate (32) of the fan.

10. An air intake grille (1) having the features of any one of claims 1 to 9.

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