EP3298284B1 - Flat flow-conducting grille - Google Patents

Description

The invention relates to a flow guide grid designed as a preliminary guide grid for arrangement on the suction area of a fan.

Vorleitgitter are known from the prior art in various designs and variants, in particular in a curved shape or as a spherical cap. Corresponding disclosures can be found, for example, in the patent applications DE 10 2014 116 047 A , EP 2 778 432 A1 , US 2 305 136 A , US 5 466 120 A1 or DE 1 052 624 B .

The flow guide grids and flow straighteners, which go back to the applicant and are known from the prior art, work very well in practice, but because of their curvature in the axial direction require a certain amount of installation space in order to function optimally. In narrow installation conditions, the curved shape is not always advantageous.

The invention is therefore based on the object of providing a flow guide grille which, in comparison to the solutions known from the prior art, requires less space in the axial direction, at the same time the performance is at least maintained and the noise generation is at least not increased. It is also an object of the invention to develop a fan with a corresponding flow guide grille into a compact structural unit.

These tasks are solved by the combination of features of the independent patent claim. According to the invention, a flow guide grille is designed as a guide grille for arrangement on a suction area of a fan, which has a grid web structure around an axial center line, which comprises radial webs spaced in the circumferential direction and coaxial circumferential webs spaced in the radial direction, and an outer ring. In the case of the flow guide grille, the inflow side extends flat and parallel to one of its radial planes. The flat, flat extension enables the turbulence minimization in the intake area on the inflow side of the flow guide grille to be exploited even in the case of narrow installation conditions.

To further reduce the required axial installation space, one embodiment of the invention provides that the flow guide grille is flat and the ratio of its maximum outer diameter D ₃ (clear width) to its overall axial height H is in a range from 6 to 25, preferably 10 to 15 is set. The flat geometry in the range of values mentioned leads to low installation heights of the flow guide grille on the fan and favors a compact overall structure.

In an advantageous embodiment variant, it is provided that a central opening with an inflow-side central diameter D _{1 is} formed in a central area of the flow guide grille around its axial center line, the ratio of the central diameter D ₁ to a maximum outer diameter D _{3 of} the flow guide grille (clear width) in one area of 1.5-6.0, preferably 2.0-2.5. The central opening is delimited radially on the outside by the first circumferential web and offers the possibility of arranging components of the connected fan in the region of the flow guide grille so that, for example, the rotor bell extends axially into the flow guide grille and thus minimizes the axial height of the fan together with the flow guide grille .

According to the invention, it is provided that the first coaxial circumferential web seen in the radial outward direction has an extension from the inflow side to an outflow side which is inclined radially outward by an angle α with respect to the axial center line. The second coaxial circumferential web seen in the radial outward direction has, according to the invention, an extension from the inflow side to an outflow side which is inclined radially inward by an angle β with respect to the axial center line.

The extensions of the first and second coaxial circumferential webs seen in the radial outward direction form an intersection in an imaginary extension of their axial end points at a distance L from the inflow side, which determines an intersection diameter D ₄ radially spaced from the axial center line, ie the circumferential webs are of this type aligned to each other that imaginary extensions of a connecting line of their respective end points intersect in a plane axially spaced from the flow guide grid. The mutually facing circumferential webs produce a flow which is advantageous for the fan performance and noise generation in a predetermined radial distance to the axial center line.

In a likewise advantageous development of the invention, the flow guide grille is characterized in that a ratio of the intersection point diameter D ₄ to an outflow-side outer diameter D _{3 of} the flow guide grille is defined in a range of 0.01-0.8. As a further advantageous ratio, the intersection diameter D ₄ compared to the axial distance of the intersection L is defined in a range of 0-1.6. In addition, according to the invention, in an embodiment variant, the ratio of the axial height H of the flow guide grille to the axial distance of the intersection point L is defined in a range of 0.01-0.5. The conditions according to the invention ensure that the air sucked in by the fan flows in and through the flat flow guide grille with a level of noise that is not increased compared to curved designs.

In the case of the flow guide grille according to the invention, it is further provided in a favorable embodiment that the first and second coaxial circumferential webs seen in the radial direction each have an axial extent H1, H2 parallel to the axial center line, the ratio of which to the axial height H is fixed at H1 <H2 <H . The axial extent of the radial webs increases over the respective radial length from the first circumferential web to the outer ring.

The first and second coaxial circumferential webs, seen in the radial direction, are advantageously curved in a convex manner in the direction of the axial center line. The shape of the circumferential webs has a direct, positive effect on the flow in the axial direction.

Furthermore, it is fluidically favorable if the flow guide grille has a plurality of radial webs, which are each spaced at a circumferential angle δ of 0-20 °, preferably 15 °. The number of radial webs is an influencing factor both on the performance of the flow guide grille and that noise generated by its use.

In an advantageous variant of the invention, the lattice structure of the flow guide lattice has a geometry in which, in an axial plan view from the inflow side, between adjacent radial webs and between the first and second coaxial circumferential webs seen in the radial direction, lattice meshes with a first diagonal extension L ₁ and between each adjacent radial webs and between the second coaxial circumferential web seen in the radial direction and the outer ring, grid meshes with a second diagonal extension L _{2 are} formed, a ratio of the diagonal extensions L ₁ <L _{2 being} fixed.

With regard to the outflow side, it is advantageous according to the invention that, in an axial plan view, between meshing adjacent radial webs and between the first and second coaxial circumferential webs seen in the radial direction, grid meshes with a first diagonal extension (L ₃ ) and between respective adjacent radial webs and between the second seen in the radial direction coaxial circumferential web and the outer ring are each meshed with a second diagonal extension (L ₄ ), a ratio of the diagonal extensions L ₃ <L _{4 is} fixed. The grid mesh geometry according to the invention enables an increased flow in the radial outer region.

The invention also includes a fan with a drive unit and a flow guide grille described above, which is characterized in that the drive unit extends at least in sections in the axial direction into a region of the flow guide grille in order to ensure the compact design.

In a further development it is also provided that the ratio of the radial distance SPm between the radial outer edge of the drive unit and the outflow-side central diameter D _{2 of} the central opening and the inflow-side central diameter D ₁ is less than or equal to a value 0.15 is set.

Fig. 1

eine Draufsicht auf die Zuströmungsseite eines Strömungsleitgitters;

Fig. 2

eine seitliche Schnittansicht einer Hälfte des Strömungsleitgitters aus Fig. 1;

Fig. 3

eine Draufsicht auf die Zuströmungsseite eines Strömungsleitgitters;

Fig. 4

eine Draufsicht auf die Abströmungsseite eines Strömungsleitgitters;

Fig. 5

eine Einbausituation des Strömungsleitgitters an einem Ventilator in einer Seitenansicht;

Fig. 6

einen Kennlinienvergleich des erfindungsgemäßen Strömungsleitgitters.

Other advantageous developments of the invention are characterized in the subclaims or are shown below together with the description of the preferred embodiment of the invention with reference to the figures. Show it:

Fig. 1

a plan view of the inflow side of a flow guide grid;

Fig. 2

a side sectional view of half of the flow guide from Fig. 1 ;

Fig. 3

a plan view of the inflow side of a flow guide grid;

Fig. 4

a plan view of the outflow side of a flow guide grid;

Fig. 5

an installation situation of the flow guide on a fan in a side view;

Fig. 6

a comparison of characteristics of the flow guide grid according to the invention.

In Fig. 1 a plan view of the inflow side of a flow guide grille 1 is shown. The flow guide grille 1 is designed as a guide grille for arrangement on the intake area of a fan 50, as is exemplarily shown in FIG Fig. 5 is shown. Around an axial center line ML, the flow guide grid 1 has a grid web structure with radial webs 2 spaced in the circumferential direction and spaced in the radial direction and coaxially arranged circumferential webs 3, 4, and an outer ring 5 closing the outer edge. A central opening 6 delimited by the innermost radial web 3 is provided in the central region around the axial center line ML.

Fig. 2 shows a side sectional view of one half of the flow guide grille 1 Fig. 1 . In the Fig. 2 Upstream inflow side of the flow guide 1 is flat and extends parallel to its radial plane, all elements of the flow guide 1, ie the outer ring 5, the radial webs 2 and the circumferential webs 3, 4 end in a radial plane of the inflow side. The outer ring 5 forms the radial and axial termination, the transition being determined by a predetermined rounding R of R = 10 mm in the exemplary embodiment. The radial webs 2 extend on the inflow side over a diameter D ₆ , on the outflow side almost to the outer ring 5, which is determined in this area by the diameter D ₃ . The circumferential webs 3, 4 extend in the radial direction on the inflow side over the diameters D ₁ , D ₅ and on the outflow side over the diameters D ₂ , D ₇ . In the axial direction, the circumferential webs 3, 4 are convexly curved from the inflow side in the direction of the outflow side in the direction of the center line, the radially inner circumferential web 3 having a curvature in the direction of the outflow side and the circumferential web 4 having a curvature in the direction of the inflow side. The circumferential web 3 also extends from the inflow side to the outflow side with respect to the axial center line at an angle of α = 18 ° inclined radially outward. The further radially outer circumferential web 4 extends from the inflow side to the outflow side with respect to the axial center line at an angle of β = -12 ° radially inward, so that the circumferential webs 3, 4 in an imaginary extension at a distance L from the inflow side Form intersection 7. The intersection 7 is radially spaced from the axial center line ML and extends in the circumferential direction at the intersection diameter D ₄ . The axial height H _{1 of} the innermost circumferential web 3 is less than the axial height H _{2 of} the second circumferential web 4, which in turn is less than the total axial height H of the flow guide grille 1, which is determined by the outer ring 5 in the embodiment shown. The radial webs 2 are designed such that their axial height increases from the innermost circumferential web 3 in the direction radially outward to the outer ring 5.

In the in the Figures 1 and 2nd shown flow guide grille 1, the ratio of the maximum outer diameter D ₃ to the axial height H has a value of 12.14. The ratio of the inflow-side central diameter D ₁ to the maximum outer diameter D ₃ is 2.19. The ratio of the intersection point diameter D ₄ to the outflow-side outer diameter D ₃ is fixed at a value of 0.74. The ratio of the intersection point diameter D ₄ to the distance L to the inflow side takes a value of 1.55. The ratio of the axial height H to the distance L to the inflow side is 0.47.

The Figures 3 and 4th each show a top view of the inflow side and outflow side of the flow guide grille 1 of FIG Figures 1-2 . The radial webs 2 are each spaced at a circumferential angle δ = 15 °, so that 24 radial webs 2 are provided in the exemplary embodiment shown. The grid meshes determined by the radial webs 2 and circumferential webs 3, 4 each have a diagonal extension, which is defined in such a way that the grid meshes which are further radially outward are larger both on the inflow side and on the outflow side. Therefore, the ratio L ₁ <L ₂ applies on the inflow side and the ratio L ₃ <L _{4 on the} outflow side.

In Fig. 5 is an installation situation of the flow guide 1 Figure 1 shown on a fan 50 in a side view. The fan 50 comprises a motor which has a rotor bell 51 with a diameter D _M. In the axial direction, the rotor bell 51 extends into the central opening 6 of the flow guide grille 1, but radially a radial distance SPm is provided between the radial outer edge of the rotor bell 51 and the outflow-side central diameter D _{2 of} the central opening (which corresponds to the outflow-side diameter of the inner circumferential web 3) . Its ratio to the inflow-side central diameter D ₁ (which corresponds to the inflow-side diameter of the inner circumferential web 3) is set at a value of 0.13.

Fig. 6 shows a comparison of characteristics, each using an inflow box, of the flow guide 1 according to the invention, the characteristics of the flow guide of 1-4 are provided with the reference number 200. In contrast, characteristic curves without a flow guide grille are identified by the reference symbol 100 and characteristic curves by a flow guide grille known from the prior art by the reference symbol 300. The positive effect of the flow guide grille 1 according to the invention with regard to noise reduction in dBA is particularly evident in the case of delivery figures (Phi) of 0.04-0.1. The total pressure difference is particularly favorable with high delivery numbers.

The embodiment of the invention is not limited to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the solution shown even in the case of fundamentally different types. For example, the number of peripheral webs is not limited to two, but any number of additional peripheral webs can be provided. The scope of the invention is defined only by the following claims.

Claims (13)

1. A flow-conducting grille designed as a pre-conducting grille for arranging on a suction region of a fan, wherein the flow-conducting grille has a grille web structure about an axial center line (ML), which grille web structure comprises radial webs (2) spaced apart in the circumferential direction and coaxial circumferential webs (3, 4) spaced apart in the radial direction and an outer ring (5), wherein an inflow side of the flow-conducting grille (1) extends flat and parallel to a radial plane of the flow-conducting grille (1), wherein the first coaxial circumferential web viewed in the radial direction has an extent from the inflow side to an outflow side, which is inclined radially outward with respect to the axial center line by an angle (α), characterized in that the second coaxial circumferential web viewed in the radial direction has an extent from the inflow side to an outflow side, which is inclined radially inward with respect to the axial center line by an angle (β).
2. The flow-conducting grille according to Claim 1, characterized in that it is designed flat and a ratio D₃/H of the maximum outer diameter (D₃) thereof to the axial height (H) is defined to be in a range of 6-25.
3. The flow-conducting grille according to Claim 1 or 2, characterized in that it is formed, in a central region, about an axial center line thereof, with a central opening (6) having an inflow-side central diameter (D₁), wherein the ratio thereof with respect to a maximum outer diameter (D₃) of the flow-conducting grille (1) is defined to be in a range of D₃/D₁ = 1.5 - 6.0.
4. The flow-conducting grille according to Claim 1, characterized in that the extents of the first and second coaxial circumferential webs (3, 4) viewed in the radial direction form, in an imaginary extension at a spacing (L) from the inflow side, an intersection point (7), which determines an intersection point diameter (D₄) radially spaced apart with respect to the axial center line (ML).
5. The flow-conducting grille according to the preceding claim, characterized in that a ratio D₄/D₃ of the intersection point diameter (D₄) with respect to the outflow-side outer diameter (D₃) of the flow-conducting grille (1) is defined to be in a range of 0.01-0.8.
6. The flow-conducting grille according to any one of Claims 4 to 5, characterized in that a ratio D₄/L of the intersection point diameter (D₄) with respect to the spacing (L) between the intersection point (7) and the inflow side is defined to be in a range of 0-1.6.
7. The flow-conducting grille according to at least one of the preceding Claims 4 to 6, characterized in that a ratio H/L of the axial height (H) of the flow-conducting grille (1) with respect to the spacing (L) between the intersection point (7) and the inflow side is defined to be in a range of 0.01-0.5.
8. The flow-conducting grille according to the preceding claim, characterized in that the first and second coaxial circumferential webs (3, 4) viewed in the radial direction each have an axial extent (H₁, H₂) parallel to the axial center line (ML), the ratio of which with respect to the axial height (H) of the flow-conducting grille (1) is defined to be H₁ < H₂ < H.
9. The flow-conducting grille according to at least one of the preceding claims, characterized in that the first and second coaxial webs (3, 4) viewed in the radial direction are formed to be curved convexly in the direction of the axial center line (ML).
10. The flow-conducting grille according to at least one of the preceding claims, characterized in that the respective radial webs (2) are spaced apart by a circumferential angle (δ) of ≤ 20°.
11. The flow-conducting grille according to at least one of the preceding claims, characterized in that, in an axial top view from the inflow side, between respective adjacent radial webs (2) and between the first and second coaxial circumferential webs (3, 4) viewed in the radial direction, grille meshes having a first diagonal extent (L₁) are formed, and, between respective adjacent radial webs (2) and between the second coaxial circumferential web (4) viewed in the radial direction and the outer ring (5), respective grille meshes having a second diagonal extent (L₂) are formed, wherein a length ratio L₁ < L₂ is defined.
12. The flow-conducting grille according to at least one of the preceding claims, characterized in that, in an axial top view from the outflow side, between respective adjacent radial webs (2) and between the first and second coaxial circumferential webs (3, 4) viewed in the radial direction, grille meshes having a first diagonal extent (L₃) are formed, and, between respective adjacent radial webs (2) and between the second coaxial circumferential web (4) viewed in the radial direction and the outer ring (5), respective grille meshes having a second diagonal extent (L₄) are formed, wherein a length ratio L₃ < L₄ is defined.
13. A fan having a drive unit as well as a flow-conducting grille according to any one of the preceding claims, characterized in that the drive unit extends at least in certain sections in the axial direction into a region of the flow-conducting grille (1), and a ratio of a radial distance (SPm) between a radial outer edge of the drive unit and an outflow-side central diameter (D₂) of the central opening (6) and the inflow-side central diameter (D₁) is defined to have a value SPm/D₁ ≤ 0.15.

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