Ventilator with ventilator wheel and guide wheel

Abstract

The invention relates to a fan with a fan wheel (2) having fan blades (3), which extends radially outwards about an axis of rotation of the fan (1) and whose radial outer circumference determines a fan wheel diameter (Dv), and a guide wheel (4) with air guide vanes (5) arranged in the axial flow direction to the fan wheel (1) at a distance (A), which extends radially outwards and has a guide wheel diameter (Dl) that is smaller than the fan wheel diameter (Dv), so that the guide wheel (4) determines a partial cross-sectional area of ​​a fan wheel cross-sectional area.

Description

[0001] The invention relates to a fan with a fan wheel and a guide wheel.

[0002] The use of guide vanes in fans is known from the prior art. For example, DE 10 2012 109 542 A1 discloses an axial fan with a guide vane designed as a flow straightener, which is also referred to in the technical field as a guide vane.

[0003] With known guide vanes, it was assumed that they ensure their greatest flow-related and noise-reducing effect in the radially outer region of fans or fan impellers, since the speed of the air flow generated by the fan is maximum in this area. The guide vane is intended to even out the flow and prevent backflow to the fan impeller, which has a negative impact on efficiency and noise levels. The known solution of the above-mentioned prior art works well in practice, but can be further improved to achieve additional positive aspects regarding the required axial installation space, the flow path, and noise levels. Further prior art is disclosed in the documents US 2006 / 067816 A1, WO 2011 / 151323 A2, and DE 103 30 088 A1.

[0004] An object of the invention is therefore to provide a fan with a laughing guide wheel which enables a compact axial design while simultaneously improving flow characteristics.

[0005] This problem is solved by the combination of features according to patent claim 1.

[0006] According to the invention, a fan is proposed with a fan impeller having fan blades, which extends radially outward around a rotational axis of the fan, and whose radial outer circumference defines a fan impeller diameter. The fan further comprises a guide wheel with air guide webs arranged at a distance from the fan impeller in the axial flow direction, which also extends radially outward and has a guide wheel diameter that is smaller than the fan impeller diameter, so that the guide wheel defines a partial cross-sectional area of ​​a fan impeller cross-sectional area.

[0007] The smaller diameter of the diffuser compared to the fan impeller makes it possible to reduce the distance between the fan impeller and the diffuser, i.e., to position the diffuser closer to the fan impeller in the direction of flow. This not only reduces the size of the fan in the axial flow direction, but also improves its noise performance. The generally known effect of homogenizing the flow and preventing backflow is retained. Furthermore, due to its small installation space requirement, the diffuser can be retrofitted to existing fans.

[0008] Another advantageous aspect of the diffuser wheel, which is smaller in diameter than the fan wheel, is that the pressure difference across the smaller cross-section of the diffuser wheel is lower, so that the risk of icing is reduced when used in refrigeration technology.

[0009] In an advantageous embodiment of the fan, the fan wheel has a fan wheel hub and a flow-through blade section that adjoins the fan wheel hub in the radial direction up to the outer circumference of the fan wheel. The stator wheel also comprises a stator hub and a guide section that adjoins the stator hub in the radial direction up to the outer circumference of the stator wheel. It is advantageous if the diameter ratio of the guide section to the blade section is in a range from 0.1 to 0.8, more preferably in a range from 0.2 to 0.5. A separate component does not have to be provided as the stator hub; rather, the stator hub can also be formed by elements of other components, for example a motor housing.

[0010] According to the invention, the diffuser is designed with a width in the axial flow direction that corresponds to 0.02 to 0.1 (i.e., 2% - 10%) of the fan impeller diameter. This means that the reference value for adjusting the diffuser width is the fan impeller diameter.

[0011] The geometric design of the diffuser has direct fluidic effects. The dimensions described above, both individually and cumulatively, lead to a reduction in the turbulent components and the radial component in the radial inner region of the airflow generated by the fan. The discharge angle in the meridian plane essentially approaches the optimal value of zero, thus eliminating the backflow against the generated flow direction that typically occurs in the hub or radial inner region.

[0012] The positive effect of the guide wheel and the compact design are further promoted by the fact that the minimum distance in the axial flow direction between the fan wheel and the guide wheel is in a range of 0.01 and 0.2, more preferably in a range of 0.01 and 0.05 of the fan wheel diameter.

[0013] According to the invention, it is also advantageous from a flow perspective that the stator has an outer peripheral ring on its radial outer circumference. The outer peripheral ring is preferably thin-walled and has a radial thickness corresponding to 0.002 to 0.015 of the fan wheel diameter.

[0014] According to the invention, the outer peripheral ring is designed to completely surround the stator and has a non-angular cross-section in axial section. In addition to its aerodynamic influence, the outer peripheral ring also promotes an increase in the stiffness of the stator.

[0015] In an advantageous further development, it is provided that the outer circumferential ring extends radially outwards in the axial flow direction at an angle β of 5 - 25°, more preferably 5 - 10°, relative to the axis of rotation.

[0016] A further design variant of the fan is characterized in that the guide wheel hub is set at an angle α of up to 60° relative to the rotation axis and extends radially outwards in the axial flow direction, ie the guide wheel hub is conical in the flow direction.

[0017] As an alternative to the stator hub, an alternative solution can be provided for the stator to have an inner ring radially adjacent to the stator hub, which extends radially outward in the axial flow direction, preferably across the entire width of the stator, at an angle α of up to 60° to the rotational axis. The adjustment of the stator hub or the inner ring adjacent to the stator hub directs the air flow generated by the fan impeller in the radial inner region in a radially outward direction, away from the rotational axis of the fan.

[0018] A design in which the angle α is greater than the angle β has also proven to be advantageous.

[0019] From a flow perspective, a design is also advantageous in which the stator hub or the inner ring forms a nozzle with the outer circumferential ring, with a flow cross-section that decreases in the direction of flow.

[0020] The air guide vanes of the guide vane are preferably designed in a manner according to the disclosure of DE102012109542A1. Other components that are standard for the fan, such as a motor and a drive shaft, are also included, even if they are not explicitly described. Other advantageous developments of the invention are characterized in the subclaims or are presented in more detail below, together with the description of the preferred embodiment of the invention, with reference to the figures. They show: Fig. 1 is a schematic half-sectioned side view of a fan according to the invention; Fig. 2 is a schematic half-sectioned side view of a fan according to the invention in a further embodiment; Fig. 3 is a schematic half-sectioned side view of a fan according to the invention in a further embodiment; Fig. 4 is a diagram with curves of the fan according to Fig. 1and the state of the art without a guide wheel.

[0021] Like reference numerals designate like parts throughout. All figures are purely schematic and serve to clarify the invention.

[0022] In Figure 1is shown in axial section through the upper half of an (axial) fan 1 with a fan wheel 2 extending radially outwards around the rotation axis RA of the fan 1 and a guide wheel 4 arranged at a very small distance A from the fan wheel 2 in the axial flow direction, wherein the distance A corresponds to a value of 0.02 of the fan wheel diameter Dv. The lower half of the fan 1, not shown, is mirror-symmetrical. The fan wheel 2 has a plurality of fan blades 3 arranged at a distance from one another in the circumferential direction, each of which extends radially outwards from the fan wheel hub 12 and thereby increases its axial width. For all exemplary embodiments, alternative shapes of the fan blades known from the art can also be used. The radially outer free end of the fan wheel blades 3 determines the outer circumference and thus the fan wheel diameter Dv.In addition, a housing part 30 forming a flow channel is indicated, into which the fan 1 is inserted with a gap 31 between the fan blades 3 and the inner wall of the housing part 30. The housing part 30 can be an external component or integrated into the fan.

[0023] The guide wheel 4 comprises a plurality of air guide webs 5 running axially through the guide wheel and extending radially outwards from the guide wheel hub 13 to the outer peripheral ring 11. The maximum guide wheel diameter DI is smaller than the fan wheel diameter Dv. Since the guide wheel 4 and the fan wheel 2 are arranged overlapping in the direction of flow, the guide wheel 4 determines a partial cross-sectional area of ​​the fan wheel cross-sectional area through which air can flow. The cross-sectional areas through which air can flow are formed by the blade section 8 extending radially outwards from the fan wheel hub 12 and the guide section 9 extending radially outwards from the guide wheel hub 13, the diameter ratio of the guide section 9 to the blade section 8 being 0.4 in the embodiment shown.The radially outer part of the blade section 8 is not covered by the guide wheel 4, so that the flow generated by the fan wheel 2 partly passes first through the guide wheel 4 and partly directly to the axial outside.

[0024] The outer peripheral ring 11 runs parallel to the rotation axis RA essentially over the entire width B of the stator 4 and is designed as a thin-walled circumferential ring whose thickness corresponds to a value of 0.01 of the fan wheel diameter Dv. The width B of the stator 4 corresponds to a value of 0.065 of the fan wheel diameter Dv. The fan wheel hub 12 and the stator hub 13 have the same hub diameter Dn.

[0025] The execution according to Fig. 2 is to that in Figure 1 except for the design of the guide wheel, so that in order to avoid repetitions, the Figure 1 The idler wheel 4 of the design according to Figure 3additionally comprises an inner ring 7, which has a section angled α of 40° relative to the rotation axis RA and extends obliquely radially outward in the axial flow direction across the entire width B of the guide vane 4. In the axial section shown, the inner ring 7 has a V-shaped cross-section with one leg engaging the guide vane hub 13 and one leg forming the angled section. The inner ring 7 effectively prevents axial backflow of air toward the fan wheel 2 in the radially inner area adjacent to the hubs 12, 13.

[0026] The execution according to Fig. 3 is identical to that in Figure 2 except that the outer peripheral ring 11 is modified. To avoid repetition, reference is therefore made to the disclosure of the Figure 1 and 2 Reference is made. According to Figure 3The outer peripheral ring 11 is set at an angle β=10° to the rotation axis RA and extends radially outward in the axial flow direction. The diffuser 4 thus forms a nozzle with a flow cross-section that decreases in the flow direction through the inner ring 7 and the outer peripheral ring 11. Due to the inclined position of the outer peripheral ring 11, the maximum diffuser cross-section increases by the length of the opposite side of the angle β.

[0027] In Figure 4 is a diagram with characteristic curves for the pressure curve psf [Pa] and the efficiency nse [%] at different volume flows qv [m 3 < / h] of the fan 1 according to Fig. 1 and the same fan without guide wheel 4, where the solid characteristic curves represent the fan 1 according to Figure 1and the dashed characteristic curves indicate the fan without a diffuser. The advantageous effect with increased peak efficiency at a flow rate of approximately 1100 m³ / h and higher pressure up to approximately 1300 m³ / h, i.e., in the highly relevant operating range, is clearly evident.

Claims

1. A fan having a fan wheel (2) comprising fan blades (3), which fan wheel (2) extends radially outwards about a rotational axis of the fan (1) and whose outer radial circumference defines a fan wheel diameter (Dv), and a guide wheel (4) with air deflecting webs (5) disposed in the axial direction of flow at a distance (A) from the fan wheel (1), which guide wheel extends radially outwards and has a guide wheel diameter (DI) that is smaller than the fan wheel diameter (Dv), such that the guide wheel (4) defines a partial cross sectional area of a fan wheel cross sectional area, wherein the guide wheel (4) has a width (B) in the axial direction of flow that is in a range from 0.02 to 0.1 of the fan wheel diameter (Dv), wherein the guide wheel (4) comprises an outer circumferential ring (11) on its outer radial circumference, wherein the outer circumferential ring (11) completely surrounds the guide wheel (4) and is non-angular in axial cross section.

2. The fan according to claim 1, characterized in that the fan wheel (2) comprises a fan wheel hub (12) and an adjoining blade section (8) that extends in radial direction from the fan wheel hub (12) to the outer circumference of the fan wheel (2), and in that the guide wheel (4) comprises a guide wheel hub (13) and an adjoining guide section (9) that extends in radial direction from said guide wheel hub (13) to the outer circumference of the guide wheel (4), wherein the diameter ratio of the guide section (9) to the blade section (8) is in a range from 0.1 to 0.8.

3. The fan according to claim 2, characterized in that the diameter ratio of the guide section (9) to the blade section (8) is in a range from 0.2 to 0.5.

4. The fan according to any one of the preceding claims, characterized in that the distance (A) in the axial direction of flow between the fan wheel (2) and the guide wheel (4) is in a range from 0.01 to 0.2, preferably in a range from 0.01 to 0.05 of the fan wheel diameter (Dv).

5. The fan according to any one of the preceding claims, characterized in that the outer circumferential ring (11) has a radial thickness that is equivalent to 0.002 to 0.015 of the fan wheel diameter (Dv).

6. The fan according to any one of the preceding claims, characterized in that the outer circumferential ring (11) extends radially outwards in the direction of flow at an angle β of 5 to 25° relative to the rotational axis.

7. The fan according to any one of the preceding claims, characterized in that the outer circumferential ring (11) extends radially outwards in the direction of flow at an angle β of 5 to 10° relative to the rotational axis.

8. The fan according to any one of the preceding claims 2 to 7, characterized in that the guide wheel hub (13) extends radially outwards in the axial direction of flow at an angle α of up to 60° relative to the rotational axis.

9. The fan according to any one of the preceding claims 2 to 7, characterized in that the guide wheel (4) comprises an inner ring (7) radially adjacent to the guide wheel hub (13), which inner ring extends radially outwards in the axial direction of flow across the entire width (B) of the guide wheel (4) at an angle α of 0 to 60° relative to the rotational axis.

10. The fan according to any one of claims 6 to 9, characterized in that the angle α is greater than the angle β.

11. The fan according to any one of claims 2 to 10, characterized in that the guide wheel hub (13) and the outer circumferential ring (11) together form a nozzle that has a flow cross section that diminishes in the direction of flow.

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