Outlet guide vane device for ventilation system and ventilation system equipped with the outlet guide vane device

Abstract

The present invention relates to an outlet guide vane device for a ventilation system having at least one impeller with impeller blades, comprising an outer housing and at least one inner outlet guide wheel with inner guide vanes, wherein the inner outlet guide wheel has an intermediate ring that is concentrically held in or on the outer housing by at least three support vanes arranged around its circumference. Furthermore, the invention relates to a ventilation system equipped with a corresponding OGV arrangement.

Description

[Technical Field]

[0001] The present invention relates to an outlet guide vane arrangement for a ventilation system having at least one impeller with impeller blades, comprising an outer housing and at least one inner outlet guide wheel with inner guide vanes, wherein the inner outlet guide wheel has an intermediate ring, which is preferably concentrically held in or on the outer housing by at least three support vanes arranged around its circumference. Furthermore, the present invention relates to a ventilation system having this OVG device. [Background technology]

[0002] Ventilation systems comprising outlet guide vane devices are well known in practice. In this regard, reference may be made to US Pat. No. 5,649,999, merely by way of example. Ventilation systems equipped with such outlet guide vane devices, particularly inner guide vane devices, have practical problems. Such an OGV arrangement then extends from the shaft across only one of the flow generating regions. Generally, these ventilators combine relatively high static efficiency with low noise emission values. The reason for this is that the outlet guide vanes, which can generate particularly loud blade passing noise, are not present in the outer region, which has a decisive influence on this noise generation. However, the ventilator motor impeller and inner outlet guide wheel must be supported in some way. The retention or suspension of OGV devices is generally complicated, reduces efficiency, and promotes noise generation. Furthermore, during operation and transportation of the ventilator, conventionally used retention means are subject to mechanical stresses and deformations, often leading to damage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 015792(A1) Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to overcome the problems encountered in the prior art. On the one hand, damage to the outlet guide wheels and the ventilation device caused by mechanical stress must be avoided. On the other hand, noise generation and efficiency loss must be minimized. Furthermore, the OGV device of the present invention must be differentiated from competing products. This also applies to the ventilation device according to the invention. [Means for solving the problem]

[0005] The OGV device of the present invention achieves the above-mentioned object by the features of claim 1. Furthermore, the above-mentioned object of the ventilation device according to the invention is achieved by the features of the additional independent claim 14. According to this aspect, the ventilation device according to the invention comprises an outlet guide vane device according to the invention. Ultimately, the focus of this invention is on the OGV device and its design features.

[0006] The OGV device according to the invention is used for integration into a ventilation system, which may be of the axial, radial or mixed flow type. The ventilation system includes at least one impeller having a plurality of impeller blades. For the basic structure of such a ventilation device, reference can be made, for example, to the above-mentioned Patent Document 1. In order to refer to this known ventilation device, a description of such a ventilation device will not be provided herein.

[0007] In accordance with the present invention, an outlet guide vane device includes an outer housing within which an outlet guide wheel having inner guide vanes is disposed. The outlet guide wheel has an intermediate ring at which the inner guide vanes terminate. More precisely, the inner guide vanes extend between the hub ring or inner ring and the intermediate ring of the OGV arrangement and are fixedly arranged therein.

[0008] It is particularly important that the intermediate ring of the outlet guide wheel is held concentrically in or on the outer housing by at least three support vanes distributed around the circumference. The support vanes have a retention or fixing function and act between the intermediate ring and the inside of the outer housing. Furthermore, the support vanes are shaped like vanes and are particularly optimized with regard to air flow and at the same time optimized for strength.

[0009] The claimed embodiments are as follows:

[0010] The individual components of the OGV device can be manufactured integrally by casting, in particular the component including the inner guide vanes being connected to the inner surface of the outer housing by the support vanes via an intermediate ring and to the outer contour of the housing. The support vanes have a flow-optimizing configuration and also have a load-bearing function.

[0011] More specifically, the support blades can be significantly tilted relative to the trailing blade edges or relative to an imaginary radius line of the impeller. Furthermore, the support blades can be positioned a relatively long distance from the trailing edges of the impeller blades. This distance may, for example, be greater than the axial length of the support vane when viewed in the axial direction.

[0012] Furthermore, the number of support vanes is preferably relatively small, and in particular smaller than the number of inner guide vanes.

[0013] Importantly, the support vanes have a smaller hydrodynamic effective area compared to the inner outlet guide vanes. Furthermore, the support vanes are relatively thick in order to ensure the necessary rigidity both during transport and during operation of the ventilator comprising them.

[0014] For example, when viewed in a cross section of the cylinder shell coaxial with the ventilator axis, the support vanes are configured at an angle and arranged so as to provide as little flow resistance as possible to the swirling flow generated by the impeller of the ventilator. Geometrically speaking, it is highly advantageous if there is no flow deflection or at most only a small flow deflection at each support vane.

[0015] Furthermore, the support vanes are fixed or formed on the outer housing in the radially expanding region at a position as far away as possible from the entrance of the radially expanding region. The undercut region formed tends to be relatively large, and if a release wedge is not used in this diameter expansion region, it is advantageous to perform release by a special release method using a slide instead. This avoids the efficiency loss and noise caused by mold release wedges integrally molded into the part, while also simplifying the injection molding manufacturing process.

[0016] In the OGV device according to the invention, the support vanes extending between the intermediate ring and the outer housing are arranged at a relatively significant inclination angle relative to the outlet edge of the impeller blades or to an imaginary radius parallel to the ventilator axis, so that no flow deflection occurs. And because the support blades are located a relatively long distance from the trailing edges of the impeller blades on the outflow side, the possibility of noise generation at the support blades is avoided or minimized.

[0017] It is also conceivable to provide a cooling structure in the OGV arrangement, preferably in the OGW. In particular, the cooling structure can be integrated into the outlet guide wheel. The cooling structure utilizes a pressure differential to create a cooling flow when the ventilator is in operation. This allows heat to be dissipated from the electric motor. Heat dissipation is accompanied by cooling.

[0018] The OGV arrangement according to the present invention is therefore advantageous in terms of stability / strength and in terms of reduced efficiency losses and noise generation. These advantages are achieved by surprisingly simple design measures according to the above description.

[0019] Various possibilities exist for improving and developing the method of the invention. For that purpose, reference is made on the one hand to the claims following claim 1 and on the other hand to the following description of an embodiment of an OVG device according to the invention and of a ventilation device comprising same, with reference to the drawings. Embodiments of the present invention will be described with reference to the drawings, and improvements and developments of the present invention will also be outlined. [Brief explanation of the drawings]

[0020] [Figure 1] 1 shows a perspective view from the outlet side of a ventilation device with a load-bearing outlet guide vane unit according to the present invention, including an outer housing, an inner outlet guide wheel and support vanes. [Figure 2a] 2 shows a plan view of the ventilation device equipped with the load-bearing OVG unit of FIG. 1 in the horizontal axis direction as viewed from the outlet side. [Figure 2b] 2a shows a detailed view of the support vane region, with the support vane profile, the ventilator vane profile and the radial lines each shown as characteristic curves projected onto the plane of the drawing. [Figure 3]1 and 2a show a ventilation device with a load-bearing OGV unit in a horizontal axial plan view from the inlet side; [Figure 4a] A ventilation device with a load-bearing OGV unit as shown in Figures 1, 2a and 3 is shown in a side view and in a cross section in a plane through the axis, with approximate dimensions in the region of the inlet nozzle. [Figure 4b] 4a shows a detailed view of the support vane region, with three characteristic variables shown diagrammatically. [Figure 4c] 4b shows another detail in the region of the support vane of FIG. 4a, where the undercut region for release from the mold in a direction parallel to the ventilator axis is indicated diagrammatically with hatching. [Figure 5a] The ventilator with the load-bearing outlet guide vane unit shown in Figures 1, 2a, 3 and 4a is shown in a side view and in a cross section in a plane parallel to the axis and plane shown, showing the support vanes. [Figure 5b] 5a shows a detailed view of the support vane region, with four characteristic variables shown diagrammatically. [Figure 6a] Another embodiment of a load-bearing OGV unit is shown in side view and in cross section through the axis, with a release wedge formed in the diameter expansion region to facilitate release. [Figure 6b] 6a shows a detailed view of the support vane and release wedge area. [Figure 7a] FIG. 1 shows a horizontal axial plan view of a ventilation system with another embodiment of a load-bearing OGV unit as viewed from the outlet side, with the turbulence profile in the impeller wake obtained by flow simulation shown on a plane perpendicular to the axis slightly downstream of the outlet trailing edge of the impeller blades. [Figure 7b] The ventilator is shown in the same flow conditions as in Figure 7a, with the flow disturbance shown in a plane perpendicular to the ventilator axis, but away from the trailing edge of the outlet side of the impeller blades, still upstream of but closer to the leading edge of the support blades. DETAILED DESCRIPTION OF THE INVENTION

[0021] FIG. 1 shows a shaft-type ventilation device 57 having a load-bearing OGV unit 1 in a perspective view from the outlet side. Specifically, the outlet guide vane unit 1 is composed of an outer housing 2, an intermediate ring 5, a hub ring 4, inner guide vanes 11 extending between the hub ring 4 and the intermediate ring 5, and support vanes 3, 3a extending between the intermediate ring 5 and the outer housing 2 and into the diameter expansion region 10.

[0022] The OGV unit 1 is manufactured in one piece by a casting process, preferably by injection molding of plastic. The outer housing 2 also defines the outer boundary of the flow through the ventilation device 57 that occurs within the outer housing 2 . The outer housing 2 is made up of various regions, which, viewed from the flow direction, are first the inlet nozzle 9, then the cylindrical region 29 in which the impeller 19 and its blades 22 are arranged, and the radially expanding region 10 in which the support blades 3, 3a are fixed.

[0023] Furthermore, an inner outlet guide wheel consisting of inner outlet guide vanes 11 that extend between the hub ring 4 and the intermediate ring 5 and influence the fluid flow is arranged downstream of the impeller 19 within the housing 2. The inner outlet guide vanes 11 interact with the intermediate ring 5 and the hub ring 4 to influence the flow, making the efficiency and air output of the ventilation device 57 particularly high. The motor 34 is fixed to the hub ring 4 via its stator 36 and is mounted in the radially inner mounting area 8 of the hub ring 4, so that the inner OGVs 11 and intermediate ring 5 also perform a load-bearing function for the motor 34 and therefore for the impeller 19.

[0024] And, outer support vanes 3, 3a are provided to hold the motor 34 with impeller 19 and the inner OGV arrangement to the outer housing 2. These have only a subordinate hydrodynamic function, primarily to secure the inner OGV arrangement, and thus the motor 34 and impeller 19, to the outer housing 2. Such a design has noise advantages, so that the presence of these vanes generates little, if any, noise during operation of the ventilator 57. Overall, within the outer housing 2, in the axial region of the radially expanded region 10, as viewed in the span direction (from the hub ring 4 to the radially expanded region 10), two distinct through-flow regions are formed: an outer through-flow region 6 between the intermediate ring 5 and the wall of the radially expanded region 10 of the outer housing 2, and an inner through-flow region 7 between the hub ring 4 and the intermediate ring 5. The inner through-flow region 7 has load-bearing inner guide elements 11 which have a hydrodynamic function, for example, reducing vortices in the flow and avoiding or reducing backflow in the hub region, and which, due to their radially inner position, generate very little noise.

[0025] The outer through-flow region 6 is also provided with load-bearing support vanes 3, 3a, in this embodiment six, preferably four to eight, distributed around the circumference and optimized in terms of noise. In this embodiment, the support blade 3a is provided with a means for fixing a cable extending from the outer housing 2 to the motor . Flanges (which advantageously have various fastening means) are provided on the inlet and outlet sides of the edge region of the outer housing 2 of the load-bearing OGV unit 1 . The inlet flange is provided with a fixing means 20 for fixing the OGV unit 1 and the ventilation device 57 to a higher-level device or system, and the outlet flange is provided with a similar fixing means 21 for fixing the OGV unit 1 to a higher-level device or system. Furthermore, the outlet flange is provided with fixing means 25 for a finger protection grid, and a similar fixing device may also be provided on the inlet flange. The finger protection grid can be screwed recessed in area 25 so that it does not protrude axially from the OVG unit 1, which makes the ventilation device 57 easier to handle and improves stackability.

[0026] The intermediate ring 5 has a wave-shaped design at its outflow edge 12, but may also have a sawtooth or grooved design. It may also be a circular shape without any corrugations.

[0027] At the mounting area 8 in the hub ring 4, the motor 34 is mounted to a motor support flange 59 (FIG. 2) which is integrally attached to the load-bearing OGV arrangement 1. Reinforcing ribs 58 are additionally provided within the mounting area 8 to strengthen and stabilize the connection with the motor 34 .

[0028] In the mold for manufacturing the load-bearing OVG unit 1, it is conceivable to provide interchangeable inserts in the inner area of ​​the hub ring 4, i.e., the mounting area 8, to allow various motors to be mounted. As well as the circular hole for fastening the motor, for example the axial screw fastening surface for the motor and the axial position of the motor support flange 59 in the mounting area 8 can also be varied.

[0029] The intermediate ring 5 and the hub ring 4 are provided with cutouts in the area leading to the support vanes 3a with the cable fastening means for routing electrical connection cables to the stator 36 of the motor 34. The motor 34 is an outer rotor type motor, and is advantageously configured as an EC motor with built-in motor electronics. In this region, the housing 2 is also advantageously provided with a cutout 50 for the passage of cables (for example as shown in FIG. 5a).

[0030] FIG. 2a shows a ventilation device 57 equipped with the load-bearing OGV unit 1 shown in FIG. 1 in an axial plan view from the outlet side. Supplementing the information on FIG. 1, the outer through-flow region 6 traversed by the support vanes 3, 3a and the inner through-flow region 7 in which the inner guide vanes 11 are present are clearly shown. During operation of the ventilator 57, the impeller 19, together with the impeller blades 22, rotates in a counterclockwise direction 32 about the ventilator axis. In the mounting area 8, the motor 34 is attached to a motor support flange 59 by means of fastening means 18, advantageously by means of screws.

[0031] The diameter of the expanding region 10 increases from a region 29 for the impeller 19 (see also FIG. 1) towards the outlet edge of the outer housing 2 . The intermediate ring 5 also flares slightly from the impeller 19 towards its outlet edge 12 (FIGS. 1, 4a and 4b). As a result, the inner through-flow region 7 and the outer through-flow region 6 are of a radially expanding design, i.e. designed to widen in the through-flow direction. This design favors pressure recovery downstream of the impeller 19 and a high static efficiency of the ventilator 57.

[0032] FIG. 2b shows a detailed view of the region of the support vane 3 of FIG. 2a, with the characteristic radial profile 24 of the support vane 3, 3a, the characteristic radial profile 26 of the impeller vane 22, and the radial line 31 each shown as a characteristic curve in a projection onto the plane of the drawing. Here, the radial profile 24 of the support vane 3, 3a is shown by the centerline of the support vane 3, 3a, for example, a centerline derived from the radial profile of the inlet leading edge 46 of the support vane 3, 3a and the radial profile of the outlet trailing edge 47 of the support vane 3, 3a when viewed in a predetermined projection. It is also entirely possible to use either the profile of the inlet leading edge 46 or the outlet trailing edge 47 alone, or to use an imaginary line connecting all of the centers of gravity of all intersections between the support vanes 3, 3a and multiple cylinder shells coaxial with the ventilation device axis.

[0033] The radial profile 26 of the impeller blade 22 is characterized based on the profile of the outlet trailing edge 39 . In this case, the sawtooth shape of the trailing edge 39 of the impeller 19 on the outlet side is not taken into account, and a "smooth" line is used. In the case of the characteristic radial profile 26 of the impeller blade 22, for example, a centerline derived from the radial profiles of the leading and trailing edges, or an imaginary line connecting all of the centers of gravity of all intersections of the impeller blade 22 with multiple cylinder shells coaxial with the ventilator axis, can be used.

[0034] FIG. 2b shows the angle γ 27 between the radial profile 24 of the support blades 3, 3a and the radial profile 26 of the impeller blade 22 at the intersection shown. Also shown is the angle δ 28 between the radial profile 24 of the support vanes 3, 3a and a radial line 31 from the ventilator axis. The angles δ28 and γ27 may vary slightly depending on the relative positions of the impeller blade 22 and the support blades 3, 3a, or depending on the position of the intersection as viewed from the radial direction. The average angle at all intersections within the outer through-flow region 6, or the angle δ 28 or angle γ 27 at intersections near the radial center of the outer through-flow region 6, are of particular importance. For a complete understanding, it should be made clear that in this description, the angles δ 28 and γ 27 should always be understood in unsigned absolute values. In particular, a large angle γ27, in particular γ>30° or γ>45°, is advantageous since it allows to minimize noise generation, in particular blade passing noise. As a further advantageous option for the same purpose, the angle δ 28 is also large, in particular δ>20° or δ>35°. Increasing the angle δ 28 may significantly reduce the stiffness of the load-bearing OGV device 1 . However, due to the reinforcement provided by the intermediate ring 5, the rigidity of the load-bearing outlet guide vane device 1 is very high, and even if the four to eight support vanes 3, 3a are strongly inclined, the impeller 19 does not rub against the outer housing 2 or the mounting area 29 for the impeller 19 during operation, and the load-bearing outlet guide vane device 1 ensures sufficient rigidity.

[0035] Furthermore, when the angle δ28 is small, it is also possible to increase the angle γ27 required to reduce the occurrence of blade passing noise. However, this configuration is only possible if the radial profile 26 of the impeller blades 22 is inclined very strongly relative to the radial direction. It has been found that this configuration is only feasible to a limited extent when the impeller blades 22 are made from injection molded plastic, due to the radial deformation that occurs during operation of the impeller blades 22. Therefore, it may be necessary and advantageous to choose a sufficiently large angle δ28 to reduce the occurrence of blade passing noise. In this embodiment, the support blades 3 extend between the intermediate ring 5 and the diameter expansion region 10 at an incline in the direction opposite to the rotation direction 32 of the impeller blades 22 . Since the absolute values ​​of the angles γ27 and δ28 are large, it is also possible to incline the support blades 3 in the same direction as the rotation direction 32, conversely. In another embodiment, different circumferentially distributed support vanes can be inclined alternately in the same direction as the direction of rotation and in the opposite direction.

[0036] FIG. 3 shows a ventilation device 57 with the load-bearing OGV unit 1 of FIGS. 1 and 2a in a horizontal axial plan view from the inlet side. 1, 2a and 2b, it is particularly clear that the impeller 19 of the ventilator 57 and its impeller blades 22 are fixed to a common hub. The impeller 19 is manufactured as a single unit by plastic injection molding. The impeller blades 22 have a special design for noise reduction, in particular they are formed with so-called winglets 38 (see also Figures 4a and 4b) on their radially outer edges. Within the impeller 19 or in its hub area can be seen the rotor 35 of the motor 34 to which the impeller 19 is fixed and which drives the impeller 19 during operation of the ventilation device 57 . Furthermore, for an aerodynamically and fluid-acoustically advantageous configuration of the ventilation device 57, a hub hood 37 of a fluid-dynamically advantageous configuration is attached to the hub region of the impeller 19 (see also Figure 4a). When viewed from the inlet side, the inlet side edge 23 of the intermediate ring 5 of the OGV device 1 and the inlet side edge 13 of the inner OGV 11 are visible. In the illustration, the direction of rotation 32 is clockwise.

[0037] Figure 4a shows a ventilation device 57 with the load-bearing OGV unit 1 shown in Figures 1, 2a and 3 in a side view and in a cross section in a plane through the axis, with approximate dimensions in the region of the inlet nozzle 9. Complementing the relevant drawings, the outer shape of the hub hood 37 can be seen particularly clearly, which is attached to the hub region of the impeller 19 and is connected to the hub of the impeller 19 with an aerodynamically advantageous rounded shape. A motor 34 is shown diagrammatically, consisting of a stator 36 and a rotor 35 . The stator 36 is fixed in a fixing device 18 on a motor fixing flange 59 inside the mounting area 8 of the load-bearing OGV unit 1 . The impeller 19 or its hub is fixed to the rotor 35 of a motor 34 using fixing means 30, preferably screws.

[0038] The motor 34 and impeller 19 are held on the outer contour of the outer housing 2 via the inner outlet guide vanes 11, the intermediate ring 5 and the support vanes 3, 3a. Therefore, the inner OGV 11, the support vanes 3, 3a and finally the entire OGV unit 1 can be referred to as load-bearing. The impeller 19 extends axially within the outer housing 2, for example at the height of the cylindrical region 29, with its impeller blades 22 and its radially outer ends having a special profile called winglets 38. Here, a small radial clearance and flow gap exists between the impeller blades 22 with the winglets 38 and the region 29 of the outer housing 2 .

[0039] The inner guide element 11 has a configuration that is advantageous for its production by casting and for its release from the mold. The inner guide element 11 includes an inlet side region 16 that is inclined with respect to the axial direction, and an outlet side region 15 that can be demolded in the axial direction without undercuts and that faces in approximately the same direction as the axial direction. This configuration is advantageous in terms of demoldability of the component known as the "load-bearing OGV unit 1", especially in combination with the slightly conical shape of the intermediate ring 5, which widens radially in the through-flow direction.

[0040] The OGV unit 1 has a particularly compact design in the radial direction. This means that the inlet diameter Da45 of the inlet nozzle 9 (diameter Da45 at the radially outer start of the curvature of the inlet nozzle 9) is relatively small compared to the inner diameter Di44, Da / Di<1.1. As a result, the transverse length e43 of the OGV unit 1 relative to the ventilator axis can also be relatively small (this length e43 can be the length of the sides of a square outline extending transversely to the ventilator axis, within which the load-bearing OGV unit 1 and thus the ventilator 57 can be integrated). It is advantageous if e / Di<1.2. As a result, viewed transversely to the axis, the ventilation device 57 has a particularly small installation space with respect to its inner diameter Di44 and therefore also with respect to the diameter of its impeller 19. Conversely, for a given installation space, it is possible to use a ventilation device 57 with a large inner diameter Di44 and therefore a particularly large outer diameter of the impeller 19, which may be acoustically advantageous at a given operating point.

[0041] Advantageously, when viewed from the radial direction, the outflow edge of the load-bearing OGV unit 1 does not protrude beyond the inflow edge. As a further advantage, the radial dimensions of the outflow edge and the inflow edge of the load-bearing OGV unit 1 are very similar to each other, i.e. the inlet nozzle 9 on the inflow side and the radially expanded region 10 on the outflow side, respectively, make maximum use of the available radial installation or transport space (the entire radial installation space excluding the required flange region) (see also Figure 1). Furthermore, during transportation, several ventilators 57 with identical OGV units 1 can be stacked on top of each other and fastened without any problems, for example by means of fastening means 20 and fastening means 21 (see FIG. 1). Preferably, these fastening means 20 and fastening means 21 at least partially coincide when viewed in projection onto a plane perpendicular to the ventilator axis.

[0042] FIG. 4b shows a detailed view of the area of ​​the support vane 3 of FIG. 4a, with three characteristic variables indicated diagrammatically. The axial distance a40 between the support blade 3 or its inlet edge 46 and the impeller blade 22 of the impeller 19 or its outlet edge 39 is relatively large, particularly to keep the generation of blade passing noise low. Here, it is also possible to use the average distance over the entire radial direction of the support vane 3 or the minimum axial distance a over the entire radial direction of the support vane 3 as the axial distance a40. The axial length b41 of the support vane 3 is measured averagely over the entire radial direction or near the radial center of the support vane 3 and is used as a reference variable for quantification. It is advantageous for a / b to be greater than 1.0, and possibly even more advantageous for it to be greater than 1.5. In order to achieve a high static efficiency of the ventilation device 57, if the radially expanding region 10 is curved evenly over its entire shape, it is advantageous if the opening angle α42 on one side of the radially expanding region 10 of the outer housing 2 is large, α>10°. This configuration is made possible by the presence of the intermediate ring 5 . Similarly, this intermediate ring 5 also expands slightly radially in the through-flow direction, so that no flow separation occurs in the region of the diameter expansion region 10.

[0043] FIG. 4c shows another detail in the region of the support vane 3 of FIG. 4a, where the undercut regions 48, 49 for release from the mould in a direction parallel to the ventilator axis are indicated diagrammatically by hatching. The undercut regions 49 are regions of the diameter expansion region 10 of the outer housing 2 that are located on the inlet side of the support vanes 3, 3a, and the support vanes 3, 3a "cover" these undercut regions 49 of the diameter expansion region 10 with respect to the axial release of the molding die parts of the OGV unit 1 that are released toward the outlet side. Conversely, this diameter expansion area 10 covers the undercut area 48 of the support vanes 3, 3a with respect to the axial release of the mold parts of the OGV unit 1 releasing towards the inlet side. In particular, since the opening angle α42 of the diameter expansion region 10 is relatively large (see FIG. 4b), the undercut regions 48, 49 are relatively large and prominent. By using a special mold configuration that allows these undercut regions 48, 49 to be demolded, these regions do not need to be filled with material or otherwise reconfigured without adversely affecting efficiency or acoustic performance. For example, a slide can be attached to a mold part that is demolded toward the inlet side and pulled axially out of the part, and the slide can be selectively engaged and moved radially inward during demolding to recreate and mold the undercut regions 48, 49. It is also conceivable to rotate the mold and the part (i.e., the OGV unit 1) relative to each other during or before the release of the molding mold part, which is released towards the outflow side and pulled axially out of the part, for example by rotating the part (i.e., the OGV unit 1) during the demolding process, thereby demolding the undercut regions 48, 49.

[0044] Figure 5a shows a ventilation device 57 with a load-bearing OGV unit 1 as shown in Figures 1, 2a, 3 and 4a in a side view and in a cross section in a plane parallel to the axis and plane shown, in which the cross section of the support vane 3 is particularly visible. The wavy shape of the outflow side edge 12 of the intermediate ring 5 in this embodiment can be clearly seen. From this figure, it can be seen that the outflow edge 12 does not protrude axially beyond the outer housing 2 at any point, and the "wave shape" is somewhat contained within the axial direction of the outer housing 2 at a short distance from the axial edge. As explained according to FIG. 1, the outlet side can be fitted with a finger protection grid, which advantageously does not protrude axially beyond the outer housing 2 . The radially extending struts of such a finger protection grid may extend into the region of a "wave trough" or recess in the outflow edge 12 of the intermediate ring 5. Also visible in the outer housing 2 is a recess 50 through which an electrical cable can be routed to the motor 34 .

[0045] FIG. 5b shows a detailed view of the area of ​​the support vane 3 of FIG. 5a, with four characteristic variables indicated diagrammatically. The axial length b41 of the support blade 3 has already been described with reference to FIG. 4b. Due to the thickness t54 of the support vanes 3, the support vanes 3 play an important role in the stiffness and strength of the load-bearing OGV unit 1. This is because a relatively small number of support vanes 3 (advantageously 4 to 8) are required to hold the entire motor 34, the impeller 19 and the inner guide arrangement, including the intermediate ring 5, the hub ring 4 and the inner guide vanes 11, on the outer housing 2. It is important that the cross-sectional rigidity moment (cross-sectional moment) of this support blade 3 is sufficiently large. In order to reduce the blade passing noise, it is advantageous to make the thickness t54 of the support blade 3 relatively large so that the axial length b41 of the support blade 3 does not become too large. Quantitatively, it is advantageous to set the maximum thickness t54 of the support blade 3 to be greater than 20% of its axial length b41. This is because the cross section of the support vanes 3 has an aerodynamically advantageous shape when viewed in cross section and at the intersection with the cylinder shell coaxial with the ventilator axis. In this cross section, the support blade 3 has an elongated shape similar to an airfoil cross section, with the inlet edge 46 being highly rounded and the outlet trailing edge 47 being slightly thinner. In this case, the centerline 60 of the cross section of the support vane 3 is aligned with the outflow from the upstream impeller 19 and its impeller blades 22 (FIG. 5a). In particular, this centre line 60 is clearly inclined relative to the ventilator axis parallel 53 since the velocity of the flow exiting the impeller 19 may have a significant circumferential component. The angle of incidence β151 of the center line 60 of the cross section of the support vane 3 at the inlet edge 46 with respect to the parallel line 53 of the ventilator axis is advantageously greater than 20° in order to minimize resistance to the flow and minimize noise.

[0046] Similarly, it has been found that the support vanes 3 provide little or no flow deflection to minimize noise and / or avoid separation in the diameter expansion region 10 . Therefore, the difference between the above-mentioned angle β151 and the angle β252 between the center line 60 of the cross section of the support blade 3 at the outlet side edge 47 and the parallel line 53 of the ventilation device axis is close to 0° in absolute value or is a small value of at most |β2-β1|<8°.

[0047] FIG. 6a shows another embodiment of a load-bearing OVG unit 1 in a side view and in a cross section through the axis, in which a release wedge 55 is formed in the area of ​​the diameter expansion region 10 to facilitate release. In Figure 6b these release wedges 55 are shown in more detail. These release wedges 55 represent a modified contour of the "optimum" contour of the outer housing 2 as described with reference to the embodiment of Figure 4c. These essentially move material from the "ideal" rotating contour of the outer housing 2 inward towards the axis in the region of the radial expansion region 10, more specifically to a localized region on the inlet side of the support vane 3. These improve the demoldability of the load-bearing OGV unit 1, which is advantageously manufactured in one piece by casting, and create the possibility of employing simpler mould technology than that described with reference to the embodiment of Figure 4c. However, the parting wedge 55 may present disadvantages in terms of static efficiency and noise generation during operation.

[0048] In the embodiment of the load-bearing OGV unit 1 shown in Figures 6a and 6b, the outlet edge 12 of the intermediate ring 5 does not have a wavy, sawtooth or similar profile, but rather has a flatter circular profile. However, in order to be able to mount the axial finger protection grid in the load-bearing OGV unit 1 without it protruding in the axial direction, the outlet edge 12 of the intermediate ring 5 is set back axially inward relative to the axial outlet edge in the area of ​​the outer housing 2.

[0049] 7a and 7b respectively show a ventilation device 57 with another embodiment of the load-bearing OGV unit 1 in a horizontal axial plan view from the outlet side, with the flow turbulence 56 profiles in the wake of the impeller 19 obtained by flow simulation shown in two different planes perpendicular to the axis downstream of the outlet trailing edge 39 of the impeller blades 22.

[0050] In FIG. 7 a these disturbances 56 are shown directly on a plane a few millimeters downstream from the outlet trailing edges 39 of the impeller blades 22 of the impeller 19 . These turbulences 56 are generated by the impeller 19 and therefore have a radial profile that is very similar to the radial profile of the impeller blades 22 , particularly at their outlet trailing edges 39 .

[0051] In FIG. 7 b these disturbances 56 are shown further downstream, directly on a plane a few millimetres upstream from the support vane 3 or its leading edge 46 . On this plane, the radial profile of the turbulence 56 is similar to that of the trailing edge 56, but is slightly offset circumferentially due to the circumferential component of the flow, and is somewhat damped due to the relatively long distance between the inlet leading edge 46 of the support vane 3 and the outlet trailing edge 39 of the impeller blade 22.

[0052] According to the knowledge that forms the basis of this technology, in order to reduce noise, it is important that these turbulences 56 do not collide parallel to the inlet-side leading edge 46 of the support vane 3 as much as possible, and that they do not collide radially with the inlet-side leading edge 46 of the support vane 3 simultaneously over the entire radial range. This is achieved based on the relationship shown in Figure 2b. This is because, in the illustrated cross section perpendicular to the ventilation system axis, the flow disturbance 56 moves downstream towards the support vane 3 and its inlet leading edge 46, approximately parallel to the radial profile of the outlet trailing edge 39 of the impeller blade 22 of the impeller 19. Furthermore, the large distance between the inlet leading edge 46 of the support vane 3 and the outlet edge 39 of the impeller blade 22, as described with reference to FIG. 4b, ensures that the intensity of the flow disturbance 56 is damped before it hits the support vane 3. [Explanation of symbols]

[0053] 1. Load-bearing outlet guide vane unit 2 Outer housing of outlet guide vane unit 3 Support blade 3a: Support vane with cable fixing means 4. Hub ring, inner ring of outlet guide vane unit 5. Outlet guide vane unit and intermediate ring in the diameter expansion area 6...outer flow area 7...Inner flow area 8 Mounting area inside the hub ring 9. Inlet nozzle 10. Wall of the diameter expansion region 11 Inner guide element, guide vane 12 Outlet edge of intermediate ring 13 Inlet side edge of inner guide element 14 Outflow side edge of inner guide element 15: A portion following the axial direction of the inner guide element 16. Inclined portion of guide element 17...not used 18. Fixing means for the mounting area 19 Impeller 20. Means for fixing the outlet guide vane unit to the host system on the inlet side 21. Means for fixing outlet guide vane unit to host system on outlet side 22 Impeller blades 23 Inlet side edge of intermediate ring of outlet guide vane unit 24 ···Profile of the support vane as a line projected onto a plane perpendicular to the ventilator axis 25 Fixing means for outlet protective grid 26 ···Profile of the impeller blade as a line projected onto a plane perpendicular to the ventilator axis 27 ···Angle γ between the profile of the support blades and the profile of the impeller blades projected onto a plane perpendicular to the ventilator axis 28 ···Angle δ between the profile of the support vane projected onto a plane perpendicular to the ventilator axis and the profile of the radial line 29 Impeller area 30. Fixing means for motor to impeller 31 Radial line from the ventilator axis 32 Impeller rotation direction 33...not used 34 Motor 35 Motor rotor 36 Motor stator 37 Hub Food 38 Impeller blade winglets 39 Outlet edge of impeller blade 40 Axial distance a between the trailing edge of the impeller blade and the leading edge of the support blade 41 Axial length of support blade b 42...Aperture angle α on one side of the diameter expansion region 43 Transverse length of OGV unit relative to ventilator axis e 44 - Inner diameter Di of the outer housing of the OGV device in the impeller region 45 - outer diameter Da of the beginning of the curvature of the inlet nozzle 9 46 Inlet side edge of support blade 47 Outflow side edge of support blade 48 Undercut area of ​​support blade 49...Undercut area of ​​the wall of the diameter expansion area 50 Cable passage in the wall of the diameter expansion area of ​​the outlet guide vane device 51 Support vane inlet angle β1 52 Support vane outflow angle β2 53 Parallel line of ventilation system axis 54 Thickness of support blade t 55 ···Release wedge / release area on the housing in the area of ​​the wall of the diameter expansion area 56 Flow turbulence in the wake of an impeller blade 57 Ventilation equipment, axial ventilation equipment 58 Reinforcing ribs in motor mounting area 59 Motor fixing flange 60: Center line of the cross section passing through the support blade

Claims

1. 1. An outlet guide vane device for a ventilation system, the device comprising: an outer housing having at least one impeller including impeller vanes; and at least one inner outlet guide wheel having inner guide vanes, the inner outlet guide wheel has an intermediate ring, which is held in or on the outer housing, preferably concentrically, by at least three support vanes arranged circumferentially.

2. 2. The OGV arrangement according to claim 1, characterized in that the number of support vanes is less than the number of inner guide vanes, preferably the number of support vanes provided is less than half the number of inner guide vanes, in particular less than 9.

3. 3. The OGV device according to claim 1, wherein the support vanes are thicker than the inner guide vanes.

4. 4. The OGV device according to claim 1, wherein the thickness of the support vane is relatively large compared to the axial length of the support vane, in particular, greater than 20% of the axial length of the support vane.

5. 5. The OGV device according to claim 1, wherein the support vanes have a hydrodynamically smaller effective area compared to the inner guide vanes.

6. 6. The OGV arrangement according to claim 1, wherein the support vanes are inclined relative to an imaginary radius line, such that the support vanes are inclined significantly relative to the trailing edges of the impeller blades.

7. 7. The OGV arrangement of claim 1, wherein the support vanes are inclined relative to the axis of the ventilator but cause little or no flow deflection when viewed in a cross section of a cylinder shell coaxial with the axis of the ventilator.

8. 8. The OGV device according to claim 1, wherein the support vanes are sized, angled and arranged to provide as little flow resistance as possible to the swirling flow generated by the impeller of the ventilation device when viewed in a cross section of the cylinder shell coaxial with the axis of the ventilation device, and the support vanes do not cause any flow deflection or cause only a small flow deflection at most.

9. 9. The OGV arrangement according to claim 1, wherein the leading edges of the support vanes are arranged at a relatively long distance from the trailing edges of the impeller blades, preferably said distance being longer in the axial direction than the axial length of the support vanes.

10. 10. The OGV device according to claim 1, wherein the support vanes are fixed or formed on the outer housing in the diameter expansion region at a position away from the inlet of the diameter expansion region.

11. 11. The outlet guide vane arrangement according to claim 1, characterized by a cooling structure integrated into the inner outlet guide wheel, the outlet guide wheel being capable of being designed as one piece.

12. 12. An OGV arrangement according to any one of claims 1 to 11, characterized in that the essential components or all said components are preferably manufactured in one piece from a casting material or by injection moulding from plastic, preferably by injection moulding from a fibre reinforced thermoplastic.

13. 13. The OGV device according to claim 1, having a load-bearing function.

14. A ventilation system, in particular an axial, radial or mixed flow ventilation system, A ventilation device comprising an OGV device according to any one of claims 1 to 13 in a downstream region of the ventilation device.

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