Fans and fan scroll housings

Abstract

This provides improved performance and optimization regarding noise generation from fans using scroll housings. [Solution] A fan 1 having an impeller 3 equipped with blades 8, an electric motor 10 that drives the impeller 3, and a scroll housing 2, wherein a flow path is formed by the inner contour of the scroll housing 2, an inlet nozzle 14 is provided on the inlet side, and the flow path guides air sucked in by the inlet nozzle 14 through the impeller 3 to the outlet, wherein the inlet nozzle 14 is surrounded by an inlet region having an inlet surface 24, the inlet region extends laterally with respect to the rotation axis of the impeller 3 which is substantially radial to the inlet nozzle 14, the ring-shaped region of the inlet nozzle 14 is at least 1.5 times the minimum flow cross-sectional region at the narrowest point of the inlet nozzle 14, and the axial height of the extended inlet nozzle 14 is less than 15% of the outer diameter of the impeller 3 on the cover plate.

Description

Technical Field

[0001] The present invention relates to a fan having an impeller with blades, an electric motor for driving the impeller, and a scroll housing, wherein a flow path is formed by an inner contour of the scroll housing, and preferably configured as a rotating body, an inlet nozzle is provided on the inlet side, and the flow path guides air sucked in by the inlet nozzle to an outlet via the impeller.

Background Art

[0002] Fans with scroll housings are widely used for forward-curved radial and mixed-flow fans. Scroll housings are increasingly being used for backward-curved fans as well. From practical experience, it has been found that by using a scroll housing, the pressure further increases, accompanied by an increase in static pressure efficiency. The scroll housing can guide the air flowing out downstream of the impeller of the fan into a flow path extending substantially perpendicular to the fan axis, for example, into a pipe having a circular or square cross-section.

[0003] In a centrifugal or mixed-flow fan, when the impeller is provided in a scroll housing, the noise level often increases, especially when the inflow is asymmetric with respect to the rotation axis of the impeller of the fan. Such an asymmetric inflow may be caused, for example, by an asymmetric geometry in the inlet region. A known scroll housing having only one outlet is inherently asymmetric with respect to the rotation axis of the impeller of the fan. As a result, this flow asymmetry also occurs around the inlet region. The increase in the noise level is a cause for concern.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, the present invention is based on the objective of optimizing fans using so-called scroll housings to improve performance with respect to noise generation. Such solutions have a simple structure and are different from the fans of competing products. [Means for solving the problem]

[0005] This objective is achieved with respect to the fan according to the present invention by the features of claim 1. Accordingly, the higher-level fan is characterized in that the inlet nozzle is surrounded by an inlet region having an inlet surface, and the inlet region widens the inlet nozzle substantially radially, that is, laterally or especially substantially perpendicularly with respect to the impeller axis.

[0006] According to the present invention, by expanding the inlet nozzle using the outer inlet surface, it was found that the inlet nozzle is expanded radially, that is, laterally or especially substantially perpendicularly with respect to the impeller axis, thereby reducing, if not eliminating, the noise problem that occurs when using a scroll housing.

[0007] It has been found that by configuring the inflow symmetrically, rather than asymmetrically with respect to the rotation axis of the fan impeller as is well known, the noise level, which is inherently higher when using a scroll housing, can be reduced. In particular, it is important to avoid asymmetrical geometric shapes in the suction region, and this is achieved by an expanded inlet nozzle with an outer inlet surface, as described in the present invention.

[0008] It is particularly advantageous if the inlet nozzle, which is extended by the inflow region, is configured to be symmetrical or rotationally symmetrical with respect to the fan axis, i.e., the fan's axis of rotation. The inflow region may be configured in the form of a rotating body.

[0009] Furthermore, it is possible that the inlet nozzle, which is expanded by the inflow area, is configured symmetrically with respect to the fan axis, but only in a broad sense. This extended inlet nozzle may have a rectangular, square, polygonal (e.g., hexagonal) or elliptical outer contour.

[0010] The inflow area or inflow surface may be configured to be substantially planar or flat. Conical or pyramidal faces are also possible.

[0011] The inlet region or inlet nozzle may extend radially to the vicinity of the radial extension of the impeller, or beyond the radial extension of the impeller, thereby particularly facilitating the inflow.

[0012] In particular, the inflow region may start radially from the outer end of the inlet nozzle, preferably from a point where its local surface curvature is significantly lower than the maximum surface curvature of the inner contour of the inlet nozzle, and this value may be less than 20%. On the other hand, in a radial view, it starts at the latest from the radial distance DRD from the narrowest point of the inlet nozzle and extends axially along the LD of the inlet nozzle.

[0013] Furthermore, the radial outer edge of the inlet region or inlet nozzle is adjacent to the contour of the scroll housing that guides the main flow, due to the transition region. The transition may be continuous or discontinuous, and may be rounded or have sharp edges.

[0014] Furthermore, the inlet nozzle, including the inlet region and optionally the transition region, is an integral part of the scroll housing, preferably the inlet-side housing half.

[0015] In this regard, it should be noted that the housing half may be made of synthetic resin. Injection molding is the ideal method for manufacturing.

[0016] Inside the scroll housing, a sub-channel that opens into the flow channel may be formed. The sub-channel controls the sub-flow that flows into the impeller between the inlet nozzle and the cover plate of the impeller, and the sub-channel extends radially beyond the impeller. This means that the sub-channel cannot be strictly separated from the main flow channel. Since the sub-channel affects not only the air performance and efficiency of the fan but also the sound radiation, it is possible to reduce the sound radiation through the configuration of the sub-channel.

[0017] The sub-channel is formed substantially rotationally symmetric with respect to the fan axis, at least with respect to its outer definition, and the inner wall of the inlet nozzle defines the sub-channel outwardly.

[0018] The scroll housing according to the present invention is characterized by the features of claim 12, that is, by the above-mentioned features of the claimed fan that relate only to the scroll housing.

[0019] Also, the scroll housing may consist of a nozzle-side housing half and a motor-side housing half, and it is essential for the scroll housing that both housing halves are manufactured by injection molding.

[0020] The housing halves may be connected to each other by screwing, riveting, bonding or clip fastening via a flange-shaped connection region.

[0021] Also, it is advantageous that the housing half is formed with a reinforcing element in the form of a reinforcing rib, especially because large pressures and pressure fluctuations may occur inside the housing, and the housing needs to withstand this.

[0022] Here, there are various options for advantageously configuring and further developing the features of the present invention. For this purpose, on the one hand, claims dependent on claim 1 and claim 12 are referred to, and on the other hand, reference is made to the description of the embodiment of the fan according to the invention based on the drawings. In connection with the description of the embodiments of the present invention based on the drawings, embodiments and developments of this feature will also generally be described.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 shows a perspective view of a fan having a scroll housing according to the invention in a side view of the inlet nozzle. [Figure 2] FIG. 2 shows a schematic view of the fan of FIG. 1 in a plane cross-sectional view through the fan axis.

Modes for Carrying Out the Invention

[0024] FIG. 1 shows a perspective view of a fan 1 having a scroll housing 2. The scroll housing 2 consists of two halves, namely, a nozzle-side half 2a and a motor-side half 2b. The two nozzle-side half 2a and motor-side half 2b are connected to each other in a connection region 16. The connection region 16 is shown as a type of flange having holes 17b through which the nozzle-side half 2a and motor-side half 2b can be connected to each other using screws. Also, other types of connections, such as clip fastening, rivet fastening and / or adhesive bonding, are conceivable.

[0025] In addition to the scroll housing 2, the fan consists of a motor 10 which has a rotor 11 and a stator 12 (see FIG. 2), and an impeller 3 consisting of a base plate 7, a cover plate 9 (see FIG. 2) and blades 8 extending therebetween is attached to the stator 12. <##

[0026] These halves 2a, 2b are advantageously manufactured by injection molding of synthetic resin. The inlet nozzle 14, through which air flows from the surroundings into the impeller 3 during fan operation, is integrated with the nozzle-side half 2a. In Figure 1, the parts of the impeller 3 (the blades 8 and base plate 7 on the suction side 35) and the rotor 11 of the motor 10 to which the impeller 3 is fixed can be seen through the inlet nozzle 14.

[0027] The inlet surface 24 is formed radially outward from the inlet nozzle 14 on the inlet side. In a radial view, the inlet surface 24 starts at the outer end of the inlet nozzle 14, particularly at a point where its local surface curvature is very low relative to the maximum surface curvature of the inner contour of the inlet nozzle 14, for example, less than 25%. At the latest, in a radial view, it starts at the radial distance DRD20 from the narrowest point of the inlet nozzle 14 and becomes the axially extending LD19 of the inlet nozzles 14 and 24 (see also Figure 2). The inlet surface 24 has a very low surface curvature, with respect to its entire shape, which is up to 25% of the maximum surface curvature of the inner contour of the inlet nozzle 14. Its radial outer edge is characterized by the starting point of the radially adjacent transition region 6. This transition region 6 connects the inflow surface 24 to the outer contour 37 of the scroll housing 2, which guides the main flow. The starting point of the transition region 6, which is radially outside the inlet surface 24, may be characterized by a sharp edge or a non-tangential transition, or, as in the embodiment, by a rounding, in which case the rounding has a higher surface curvature than the inlet surface 24, and the inlet surface 24 has a surface curvature of up to 25% of the maximum surface curvature of the inner contour of the inlet nozzle 14. Here, the local mean surface curvature of the two principal curvatures of the surface is always constituted as the surface curvature.

[0028] It is advantageous if the transition from the inlet nozzle 14 to the inflow surface 24 extends smoothly in the tangential direction. The inlet nozzle 14, together with the inlet area 24, may be considered as one type of extended inlet nozzle 14,24. The shape of the inlet region 24 or the expanded inlet nozzles 14, 24 is important because this region affects the distribution of flow velocity (radial and circumferential views) as the flow enters the impeller 3 through the inlet nozzle 14. For high efficiency and low noise radiation, it is important that this inflow has a velocity distribution that is as symmetrical as possible with respect to the impeller's rotation axis.

[0029] Through testing and simulation calculations, it was confirmed that this is best achieved by a configuration that is as symmetrical as possible with respect to the impeller's axis of rotation, and by sufficient radial extension of the inlet region 24 or the extended inlet nozzles 14, 24.

[0030] In the embodiment shown in Figure 1, the inlet area 24 or the extended inlet nozzles 14, 24 are configured symmetrically with respect to the axis of rotation. It is advantageous that the inflow region 24 is actually formed entirely by a rotating surface, and the radial outer edge of the inflow region 24 has a circular shape concentric with the axis of rotation. In this embodiment, the inflow region 24 is substantially flat over a wide area and extends perpendicularly to the axis of rotation.

[0031] Other configurations of the inlet region 24 or the extended inlet nozzles 14,24 are also conceivable, as long as the inlet region 24 or the extended inlet nozzles 14,24 are symmetrical with respect to the fan axis, preferably rotationally symmetrical. This also applies to shapes with rotational symmetry in a broad sense, such as the outer contours of roughly hexagonal, rectangular, square, or elliptical shapes that simply possess rotational symmetry by a specific angle of rotation (not a multiple of 360°), at least in terms of rotation.

[0032] Furthermore, the inlet surface 24 does not necessarily have to have a flat area; for example, it may be conical in shape or extend at an angle other than 90° with respect to the axis of rotation.

[0033] On the other hand, the relatively large radial extension of the expanded inlet nozzles 14 and 24 is also essential to achieve the most uniform inflow possible. For example, the ring-shaped region of the extended inlet nozzles 14,24 projected onto a plane perpendicular to the axis of rotation is at least 1.5 times the minimum flow cross-sectional area at the narrowest point of the inlet nozzle 14. Furthermore, it is advantageous for the radial outer edge of the inlet region 24 to extend radially outward from the impeller 3 or its cover plate 9 (see also Figure 2).

[0034] The fixed flange 15 is formed in the area around the outlet 5 from the scroll housing 2, and it is advantageous that air flows out from this outlet 5 and into a flow path having a corresponding shape. The entire fan 1 can be fixed to a surrounding structure, such as an air conditioning system or an air duct, using this fixing flange 15. In this embodiment, a screw-mountable hole 17a is used for this purpose. Because significant overpressure may occur inside the scroll housing 2, specifically in its main flow path 21 (see Figure 2), during operation compared to the external environment, reinforcing elements 18, in this case reinforcing ribs 18, are provided in the two nozzle-side halves 2a and motor-side halves 2b, which are manufactured by synthetic resin injection molding, for better dimensional stability.

[0035] During operation, impeller 3 rotates clockwise in the view shown in Figure 1. Therefore, it is a rearward-curved impeller 3, that is, an impeller 3 having rearward-curved blades 8. In the case of a rearward-curved impeller 3, the blade pressure side 36 (see Figure 2) of the blade 8, which precedes the blade suction side 35 of the same blade 8 in the direction of rotation of the impeller 3 during operation, has a convex shape, while the blade suction side 35 has a concave shape. In particular, when considering the shape of the blade 8 from the radially inward (from the tip of the blade 8) to the radially outward (towards the trailing edge of the blade 8), the blade 8 is curved and / or inclined against the direction of rotation.

[0036] Figure 2 shows a side view of the fan 1 having the scroll housing 2 of Figure 1 in a plan view through the fan axis 25. In the motor-side half 2b of the housing 2, the motor 10, which has its stator 12, is fixed to a corresponding fixing device that is integrated with the motor-side half 2b in the motor support region 30. In this embodiment, the impeller 3, which is advantageously manufactured using synthetic resin injection molding, is fixed to the rotor 11 of the drive motor 10 at its base plate 7. In fact, various types of fastening exist, for example, using a thin metal disc cast into a synthetic resin impeller, which is done by adhesive bonding or compression.

[0037] During fan operation, the transported air flows radially outward from the impeller 3 into the main flow path 21 of the housing 2, which extends substantially circumferentially with respect to the rotation axis 25 of the impeller 3. From the narrowest point of the tongue region, the main flow path 21 widens its shape circumferentially, accommodating an airflow that increases circumferentially from the scroll housing 2 towards the outlet 5 (Figure 1). The main flow channel 21 is substantially defined radially outward by an inner contour 4 defined by an outer flow contour 37.

[0038] The secondary channel 22, which cannot be strictly separated from the main channel 21, is provided adjacent to the main channel 21. The flow in the secondary channel 22 controls the secondary flow that flows into the impeller 3 between the inlet nozzle 14 and the cover plate 9 of the impeller 3. The configuration of the sideflow region 22 is very important because this sideflow has a significant impact on the fan's air performance, efficiency, and sound radiation. In Figure 2, it can be seen that the subchannel 22 is largely defined by the configuration of the inlet area 24 or the extended inlet nozzles 14, 24. The wall contours defining the extended inlet nozzles 14 and 24 on the outside define the sideflow region 22 on the inside. Both the rotationally symmetric configuration of the extended inlet nozzles 14,24 in at least a broad sense, and the relatively large radial extension of the inlet region 24 and the resulting rotationally symmetric and relatively large radial extension of the sideflow region 22 in at least a broad sense, have also been found to be advantageous with respect to the aforementioned sideflow.

[0039] To characterize the radial extension of the inlet nozzle 14 or the inner edge of the inflow region 24 in a radial view, Figure 2 shows, as dimensions, the axial extension LD19 of the extended inlet nozzles 14,24 and the radial distance DRD20 between the narrowest radial innermost point of the inlet nozzle 14's contour and its radial outer end or the radial inner edge of the inflow region 24. This radial distance DRD20 is less than or equal to the axial extension LD19 of the extended inlet nozzles 14,24, and the inlet region 24 starts at this radial point at the latest.

[0040] To characterize the significant radial extensions of the extended inlet nozzles 14, 24 and the inlet surface 24, two further dimensions are shown in Figure 2, in particular, the outer diameter DL33 of the impeller 3 and the outer diameter D1 of the inlet surface 24 in its cover plate 9. Depending on the configuration of the extended inlet nozzles 14,24, the value of D1 may vary in the circumferential direction, in which case the circumferential average value D1,average or the minimum value D1,min can also be used. Advantageously, both D1 or D1,average and the minimum value D1,min are greater than the impeller diameter DL at the cover plate 9 of impeller 3. In particular, in the embodiment, D1,average>1.05DL.

[0041] Furthermore, in Figure 2, it can be seen that the inner contour 4 of the scroll housing of the motor-side half 2b is defined radially inward by the pressure-side transition contour 31, and that this pressure-side transition contour 31 is connected to the integrated motor support region 30. In this transition region 31, the inner contour 4 substantially represents the virtual continuity of the base plate 7 of the impeller 3 further outward in the radial direction, and there is only a relatively small distance between the radial outer edge of the base plate 7 and the inner edge of the helical inner contour 4. The inner contour 4 of the scroll housing of the nozzle-side half 2a is defined radially inward by the suction-side transition contour 23, which defines the transition region 6 radially inward, while further extension defines the expanded inlet nozzles 14, 24 radially inward.

[0042] Furthermore, it can be seen that the cross-section of the main channel 21 is significantly smaller in the lower region of the figure than in the upper region. The cross-section of the main flow path 21 extends in the circumferential direction, the flow direction, or the rotational direction of the impeller 3, from the narrowest cross-section of the tongue region toward the outlet 5 (see Figure 1). In contrast, the flow cross-section of the subchannel 22 shows little change in a circumferential view, or changes periodically with respect to the fan axis 25, along with a periodic angle of 180° or less in a circumferential view. This is directly related to the configuration of the extended inlet nozzles 14, 24, which are symmetrical with respect to the fan axis 25. In the circumferential direction, the cross-section of the sub-flow channel 22 changes only slightly, at most only periodically, which has a favorable effect with respect to the sub-flow flowing into the impeller 3 between the inlet nozzle 14 and the cover plate 9, and therefore has a favorable effect with respect to the fan's air performance, efficiency, and acoustics.

[0043] In Figure 2, the scroll housing 2 and, consequently, the compact configuration in the axial direction of the fan 1 can be clearly seen. The expanded inlet nozzles 14, 24 or inlet areas 24 do not extend axially beyond the outer contour 37 of the scroll housing 2 that guides the main flow; in other words, the expanded inlet nozzles 14, 24 do not require more axial installation space than is necessary due to the outer contour 37 of the scroll housing 2, which is required in any case. Such a compact configuration is highly advantageous when using such fans in ventilation systems for controlled living space ventilation, and, depending on the circumstances, maximizes the inflow space between the extended inlet nozzles 14, 24 and the walls of the ventilation system spaced apart therefrom, ensuring good inflow conditions. To achieve this, the axial height LD19 of the extended inlet nozzles 14,24 is relatively low, and in particular, less than 15% of the outer diameter DL33 of the impeller 3 at its cover plate 9.

[0044] Further embodiments of the features of the present invention are referred to in the general portion of this specification and the appended claims in order to avoid repetition.

[0045] Finally, embodiments of the features according to the present invention are provided solely for the purpose of discussing the claimed features, and are not limited thereto. [Explanation of Symbols]

[0046] 1. Fan 2. Scroll housing, housing 2a...Scroll housing / Housing nozzle side half 2b...Scroll housing / Motor side half of the housing 3. Impeller 4. Inner contour / scroll contour 5...exit 6. Transition Area 7. Impeller base plate 8. Impeller blades 9. Impeller cover plate 10.. motor 11. Motor rotor 12. Motor stator 13. Fixed impeller motor 14. Inlet nozzle 15. Fixed flange 16. Connection area 17a...hole 17b...hole 18. Reinforcement elements, reinforcing ribs 19. Axial height LD of the extended inlet nozzle 20. Radial distance between the narrowest cross-section of the inlet nozzle and the radial outer end of the inlet nozzle or the radial inner end of the inlet surface. 21. Main channel in scroll housing 22. Subchannels in scroll housings 23. Suction side transition contour 24...Inflow surface 25... Fan axis 30...Integrated motor support area 31. Pressure-side transition contour 32...Outer diameter dimension D1 of the inlet surface 24 33. Outer diameter of impeller 3 at cover plate 9 35... Blade (suction side) 36... Blade pressure side 37. Outer contour of the scroll housing guiding the mainstream

Claims

1. A fan comprising an impeller with blades, an electric motor for driving the impeller, and a scroll housing, wherein a flow path is formed by the inner contour of the scroll housing and is configured as a rotating body, an inlet nozzle is provided on the inlet side, and the flow path guides the air drawn in by the inlet nozzle through the impeller to the outlet, The inlet nozzle is surrounded by an inlet region having an inlet surface, The inlet region extends laterally with respect to the rotation axis of the impeller, which is substantially radial to the inlet nozzle. The ring-shaped region of the inlet nozzle is at least 1.5 times the minimum flow cross-sectional area at the narrowest point of the inlet nozzle. A fan characterized in that the axial height of the expanded inlet nozzle is less than 15% of the outer diameter of the impeller in the cover plate.

2. The fan according to claim 1, characterized in that the inlet nozzle, which is expanded by the inlet region, is symmetrical or rotationally symmetrical with respect to the fan axis (the axis of rotation of the fan).

3. The fan according to claim 2, characterized in that the inflow region is configured in the form of the rotating body.

4. The fan according to claim 1, characterized in that the inlet nozzle, which is extended by the inflow region, is symmetrical with respect to the fan axis in a broad sense and has a rectangular, square, polygonal (e.g., hexagonal) or elliptical outer contour.

5. The fan according to any one of claims 1 to 4, characterized in that the inflow region is substantially planar or flat, conical or pyramidal in shape.

6. The fan according to any one of claims 1 to 5, characterized in that the inflow region extends radially to the vicinity of the radial extension of the impeller, or beyond the radial extension of the impeller.

7. The fan according to any one of claims 1 to 6, characterized in that the inflow region starts from the outer end of the inlet nozzle when viewed radially.

8. The radial outer edge of the inflow region is adjacent to the contour of the scroll housing that guides the main flow, by the transition region. The fan according to any one of claims 1 to 7, characterized in that the transition region may be continuous or discontinuous, rounded, or have edges.

9. The fan according to claim 8, characterized in that the inlet nozzle, together with the inflow region and the transition region, is an integral part of the scroll housing.

10. A sub-channel is formed inside the scroll housing, The aforementioned sub-flow channel is open to the flow channel and controls the sub-flow that flows into the impeller between the inlet nozzle and the impeller cover plate. The fan according to any one of claims 1 to 9, characterized in that the sub-flow channel extends radially beyond the impeller.

11. The aforementioned sub-channel is formed to be substantially rotationally symmetric with respect to the fan axis, at least with respect to its outer definition. The fan according to claim 10, characterized in that the inner wall of the inlet nozzle defines the sub-flow channel outward.

12. A scroll housing according to any one of claims 1 to 11.

13. The scroll housing according to claim 12, characterized in that it consists of a nozzle-side housing half and a motor-side housing half.

14. The scroll housing according to claim 13, characterized in that the two housing halves are connected to each other via a flange-shaped connection area by screwing, riveting, bonding, or clipping.

15. The scroll housing according to claim 13, characterized in that the housing half is formed having reinforcing elements in the form of reinforcing ribs.

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