CN216788809U - Current collector for centrifugal fan and multi-wing centrifugal fan applying same - Google Patents

Abstract

The utility model relates to a current collector for a centrifugal fan and a multi-wing centrifugal fan using the same, wherein the current collector comprises: a stationary ring; the flow guide part is connected to the inner side of the fixed ring and is provided with an inlet end and an outlet end which are opposite to each other in the direction of the central axis; at least part of the periphery of the outlet end of the flow guide part is provided with noise reduction sheets formed by extending along the flowing direction of the oil smoke, and noise reduction holes are distributed on the noise reduction sheets. The collector can avoid self-sustaining airflow oscillation caused by flow field distortion inside the volute of the centrifugal fan, and eliminate high-frequency pneumatic noise.

Description

Current collector for centrifugal fan and multi-wing centrifugal fan applying same

Technical Field

The utility model relates to the technical field of centrifugal fans, in particular to a current collector for a centrifugal fan and a multi-wing centrifugal fan applying the current collector.

Background

The centrifugal fan is an important air supply device and is commonly used in products such as a range hood, an air conditioner and the like. The centrifugal fan generally includes a volute, an impeller, a motor, and a current collector, wherein the current collector is an important component of the centrifugal fan, and is generally installed in an air inlet area of the fan, and is used for reducing air inflow loss of the fan and air backflow between an end ring of the impeller and the volute, improving fan efficiency, and reducing operating noise.

For example, the application number CN201210230512.8 (No. CN102767541B) discloses a noise reduction flow-collecting ring, which is disposed at an air inlet of a volute of a range hood, and includes an outer ring, the outer ring includes an air guide surface extending from the air inlet to the volute, an outer ring fixing surface located on the circumferential outer side of the air guide surface and used for fixing with the volute, and an inner ring located on the inner side of the outer ring, and the inner ring includes an isolation surface which is matched with the air guide surface and blocks a turbulent flow area in the volute, and an inner ring fixing surface located on the circumferential outer side of the isolation surface and used for fixing with the volute. An inner ring is added to the collecting ring, and the collecting ring is provided with an isolation surface for blocking a turbulent flow area, so that the turbulent flow area formed in the volute can be blocked, and the air flow in the volute is improved; through holes or blind holes are densely distributed on the isolation surface, so that turbulent flow enters the cavity and consumes sound energy after multiple reflections or friction in the blind holes; compared with a layer of flow collecting ring without a noise reduction structure, the range hood can effectively reduce noise.

Although the flow collector in the above patent has a certain noise reduction effect, there still exists a certain disadvantage that there exists a radial gap and an axial gap between the flow collector and the front end face of the impeller, and a cavity is formed in the circumferential direction due to the radial gap and the axial gap between the flow collector and the impeller, and before the gas flows into the flow channel at the tip of the blade, the gas needs to turn around through the outlet end of the flow collector, and the flow is separated at this point, so that a separation flow is formed in the radial gap. Particularly, when the volute is designed to have a chamfer area or a linear line segment (as disclosed in the centrifugal fan volute for the range hood with the application publication number of CN 106762837A), the internal flow field of the volute is distorted at this point, the airflow is accelerated, and the pressure is raised, wherein a shear layer is formed in a radial gap between the outlet end of the collector and the impeller due to the continuous gas inflow, and due to the existence and rotation of the wall surface of the blade, the shear layer collides with the wall surface of the blade, and pressure disturbance and rotation are generated, so that in the tip area of the blade, the circular flow of disturbance impact, pressure return and re-impact is easy to form self-sustaining oscillation, and high-frequency aerodynamic noise is generated.

Therefore, the current collector for the centrifugal fan needs to be further improved.

SUMMERY OF THE UTILITY MODEL

The first technical problem to be solved by the present invention is to provide a collector for a centrifugal fan, which can avoid self-sustaining airflow oscillation caused by flow field distortion inside a volute of the centrifugal fan and eliminate high-frequency aerodynamic noise, in view of the current situation of the prior art.

The second technical problem to be solved by the present invention is to provide a multi-blade centrifugal fan using the above collector, aiming at the current situation of the prior art.

The technical scheme adopted by the utility model for solving the first technical problem is as follows: a collector for a centrifugal fan, comprising:

a stationary ring;

the flow guide part is connected to the inner side of the fixed ring and is provided with an inlet end and an outlet end which are opposite to each other in the oil smoke flowing direction;

at least part of the periphery of the outlet end of the flow guide part is provided with noise reduction sheets formed by extending along the flowing direction of the oil smoke, and noise reduction holes are distributed on the noise reduction sheets.

In order to ensure the flow guiding effect of the collector, the flow guiding part comprises a first flow guiding part and a second flow guiding part, the first flow guiding part extends from the inner side of the fixing ring radially inwards and is bent and protruded against the flow direction of the lampblack, the second flow guiding part extends from the inner side of the first flow guiding part along the flow direction of the lampblack, and the noise reduction sheets are connected to the second flow guiding part.

In order to improve the stability of the anti-vortex effect and ensure that the air inlet efficiency of the impeller is not lost, the noise reduction sheet is an arc sheet body formed by extending a section of the periphery of the outlet end of the flow guide part along the flowing direction of the oil smoke, the corresponding angle of the radian of the noise reduction sheet is alpha, wherein the alpha is more than or equal to 30 degrees and less than or equal to 120 degrees.

In order to reduce the gas separation at the outlet end of the current collector and reduce the flow loss, the noise reduction sheet is provided with a front edge far away from the flow guide part and two side edges opposite in the circumferential direction, the distance between the two side edges is gradually reduced along the oil fume flowing direction, the middle area of the noise reduction sheet is a conical surface, the vertex angle of the conical surface is theta, and the angle is more than or equal to 30 degrees and less than or equal to 90 degrees.

Preferably, in order to ensure the noise reduction uniformity of the region where the noise reduction sheet is located, the diameter of the noise reduction hole is d, and the value range is as follows: d is more than or equal to 1.5mm and less than or equal to 3mm, the noise reduction holes are uniformly distributed on the noise reduction sheet, the distance between every two adjacent noise reduction holes is s, and the value range is as follows: s is more than or equal to 4mm and less than or equal to 6 mm.

In order to facilitate processing consideration and reduce production cost, the noise reduction sheet and the flow guide part are designed integrally.

The technical scheme adopted by the utility model for solving the second technical problem is as follows: the multi-wing centrifugal fan applying the current collector for the centrifugal fan comprises a volute with an air inlet, an impeller arranged in the volute and the current collector, wherein the current collector is arranged at the air inlet of the volute, and the noise reduction sheet extends into the impeller and has a gap with a curved surface limited by the inner diameter of the impeller.

In order to match the size of the noise reduction sheet with the size of an impeller of a centrifugal fan, avoid the problem that a stable flow field cannot be achieved due to the fact that the axial overlapping of the noise reduction sheet and the impeller is small and the problem that the fan performance is influenced due to the fact that the noise reduction sheet extends into the impeller too much, the impeller comprises a front disc, a rear disc and blades arranged between the front disc and the rear disc along the circumferential direction, the height of each blade is b, the axial size of the noise reduction sheet of the current collector on the central axis of the fixed ring is L, and L/b is more than or equal to 0.1 and less than or equal to 0.15.

Preferably, the distance between the outer wall surface of the noise reduction sheet and the curved surface defined by the inner diameter of the impeller is marked as m, wherein m is more than or equal to 4mm and less than or equal to 8 mm.

In order to carry out targeted noise reduction on an internal flow field of a volute with a bending portion, the volute comprises a front cover plate, a rear cover plate and a ring wall connected between the front cover plate and the rear cover plate, the bending portion inclined towards the direction of the rear cover plate is formed at the lower portion of the front cover plate, a noise reduction sheet of a current collector is an arc sheet body formed by extending one section of the periphery of the outlet end of the flow guide portion along the flow of flue gas, and the noise reduction sheet is located on the radial direction of the current collector and corresponds to the bending portion of the volute.

In order to ensure the stable vortex-preventing and noise-reducing effects of the current collector, a bending line is defined on the front cover plate by the bending part, the bending line is intersected with a molded line defined by the outer periphery of the front cover plate and defines a first bending point and a second bending point, a connecting line between the first bending point and the center of the air inlet is a first straight line, a connecting line between the second bending point and the center of the air inlet is a second straight line, an included angle formed by the intersection of the first straight line and the second straight line is beta, and an angle corresponding to the radian of the noise reduction sheet is alpha, wherein alpha is larger than or equal to beta.

Compared with the prior art, the utility model has the advantages that: the flow field distribution of a gap between the current collector and the impeller can be effectively improved by adding the noise reduction sheet at the outlet end of the flow guide part of the current collector, so that inlet airflow flowing through the noise reduction sheet moves to the root part of the impeller blade, the vortex strength of the tip part of the blade is weakened, and the flow condition of the gap between the current collector and the impeller is optimized, thereby avoiding self-sustaining airflow oscillation caused by flow field distortion inside a volute of the centrifugal fan, eliminating high-frequency pneumatic noise and improving the sound quality of the centrifugal fan.

Drawings

Fig. 1 is a schematic perspective view of a current collector according to an embodiment of the present invention;

FIG. 2 is a front view of a current collector of an embodiment of the present invention;

FIG. 3 is a top view of a current collector of an embodiment of the present invention;

FIG. 4 is a front view of a centrifugal fan according to an embodiment of the present invention;

FIG. 5 is an axial cross-sectional view of a centrifugal fan in accordance with an embodiment of the present invention;

fig. 6 is a schematic perspective view of a centrifugal fan according to an embodiment of the present invention (where the bent portion is located at a lower left position of the front cover plate).

Detailed Description

The utility model is described in further detail below with reference to the accompanying examples.

Directional terms such as "front," "rear," "upper," "lower," "left," "right," "side," "top," "bottom," and the like are used in the description and claims of the present invention to describe various example structural portions and elements of the utility model, but are used herein for convenience of description only and are to be determined based on the example orientations shown in the drawings. Because the disclosed embodiments of the present invention may be oriented in different directions, the directional terms are used for descriptive purposes and are not to be construed as limiting, e.g., "upper" and "lower" are not necessarily limited to directions opposite or coincident with the direction of gravity.

Referring to fig. 1-6, a collector for a centrifugal fan is provided for being disposed at an air inlet 44 of a volute 40 of the centrifugal fan for reducing an intake flow loss of the fan and a backflow of air between an end ring of an impeller 50 and the volute 40, improving fan efficiency and reducing operational noise.

Referring to fig. 1, the collector includes a fixed ring 10 and a flow guiding portion 20, the flow guiding portion 20 is connected to the inner side of the fixed ring 10, the fixed ring 10 is used for being mounted and connected with the periphery of an air inlet 44 of a volute 40, and the fixed ring 10 is provided with connecting holes (not shown) arranged along the circumferential direction. The stationary ring 10 has a central axis O, the central axis O of the stationary ring 10 being substantially collinear with the axis of the impeller 50 within the volute 40. Opposite first and second directions O1 and O2 are formed along the central axis O of the stationary ring 10, wherein the fume flow direction substantially coincides with the aforementioned second direction O2 and the fume flow direction opposite thereto substantially coincides with the aforementioned first direction O1.

Referring to fig. 2, the flow guide portion 20 is generally annular and has an inlet end 23 and an outlet end 24 opposite to each other in the direction of the central axis O (i.e., in the direction of the flow of the cooking fumes). Specifically, the flow guide 20 includes a first flow guide 21 extending radially inward from the inner side of the stationary ring 10 and protruding to be bent in the first direction O1, and a second flow guide 22 extending from the inner side of the first flow guide 21 in the second direction O2, wherein a port defined by the front side of the first flow guide 21 is the inlet end 23, and a port defined by the rear side of the second flow guide 22 is the outlet end 24.

At least a portion of the periphery of the outlet end 24 of the second flow guiding portion 22 has noise reduction fins 30 formed to extend in the lampblack flowing direction (in a preferred embodiment, the noise reduction fins may extend in the second direction O2), and preferably, in order to improve the stability of the anti-vortex effect and ensure that the intake efficiency of the impeller 50 is not lost, the noise reduction fins 30 are an arc-shaped fin body formed to extend in the lampblack flowing direction on the periphery of the outlet end 24 of the second flow guiding portion 22, that is, the cross section of the noise reduction fins 30 is an arc, and the radius of curvature of the arc is the same as the radius of curvature of the second flow guiding portion 22. Specifically, the included angle that the radian of the noise reduction sheet 30 corresponds is α, and the value of this included angle α can be rationally designed according to the size of the bending portion 410 area of the volute 40, specifically, the value range can be: alpha is more than or equal to 30 degrees and less than or equal to 120 degrees, and the detail is shown in figure 3. When the collector is mounted, the noise reduction fins 30 are located at positions corresponding to the bent portions 410 (described in detail below) of the volute 40.

Referring to fig. 2, the noise reduction plate 30 is distributed with noise reduction holes 33. In this embodiment, the diameter of the noise reduction hole 33 on the noise reduction plate 30 is d, and the value range is: d is more than or equal to 1.5mm and less than or equal to 3mm, preferably 2 mm. The noise reduction holes 33 are uniformly arranged on the noise reduction sheet, wherein the distance between two adjacent noise reduction holes 33 is s, and the value range is as follows: s is more than or equal to 4mm and less than or equal to 6mm, preferably 5mm, and is shown in detail in figure 2.

With continued reference to fig. 2, the noise reduction plate 30 of the present embodiment has a front edge 31 away from the flow guiding portion 20 and two circumferentially opposite side edges 32, the two side edges 32 are connected to both sides of the front edge 31, specifically, the distance between the two side edges 32 gradually decreases along the lampblack flowing direction (i.e., the second direction O2), and the middle region of the noise reduction plate 30 is a conical surface with a vertex angle θ, wherein θ is greater than or equal to 30 ° and less than or equal to 90 °, and the structural design of the above-mentioned vanes 53 can reduce the gas separation at the outlet end 24 of the collector and reduce the flow loss.

Referring to fig. 4 and 5, the present embodiment further relates to a multi-wing centrifugal fan applying the collector for a centrifugal fan. The centrifugal fan includes a volute 40 having an air inlet 44, an impeller 50 disposed within the volute 40, and a current collector disposed at the air inlet 44 of the volute 40.

The volute 40 includes a front cover plate 41, a rear cover plate 42, and an annular wall 43 connected between the front cover plate 41 and the rear cover plate 42. The front cover plate 41 is provided with the air inlet 44, and the two end portions of the front cover plate 41, the rear cover plate 42 and the annular wall 43 together define an air outlet 46 for the air flow in the scroll casing 40 to flow out. The impeller 50 includes a front disk 51, a rear disk 52, and blades 53 circumferentially arranged between the front disk 51 and the rear disk 52, and a port of the front disk 51 of the impeller 50 corresponds to the air inlet 44 of the scroll 40. The structures of the volute 40 and the impeller 50 are all the prior art and are not described in detail herein.

Due to structural limitations of the whole range hood or the fan frame, design requirements of structure and performance are usually taken into consideration in the manner of a linear line segment or a corner cut of the volute 40 when the volute 40 of the centrifugal fan is designed. For example, fig. 4 shows that the front cover plate 41 of the volute 40 is bent right below, and fig. 6 shows that the left lower corner of the volute 40 is bent to weaken the asymmetry of the volute 40 and adjust the circumferential air intake of the impeller 50. However, in the above solution, the gas flow is accelerated due to the contraction of the cross section of the internal flow passage of the volute 40, which is likely to cause secondary flow of the gas, thereby increasing the noise of the whole machine or generating abnormal noise.

For this purpose, the noise reduction plate 30 of the current collector of the present embodiment is an arc-shaped plate body extending along the oil smoke flowing direction on the periphery of the outlet end 24 of the guiding portion 20, wherein the noise reduction plate 30 corresponds to the bent portion 410 of the volute 40 in the radial direction of the current collector, that is, when the bent portion 410 of the volute 40 is located right below the volute 40, the noise reduction plate 30 of the current collector also corresponds to a position right below the central axis O of the current collector, and when the bent portion 410 of the volute 40 is located left below the volute 40, the noise reduction plate 30 of the current collector also corresponds to a position left below the central axis O of the current collector, as shown in fig. 4 and 5 in detail, the structural schematic diagram of the noise reduction plate 30 of the current collector is shown to be located right below the central axis O of the current collector.

In addition, referring to fig. 4, another important point of the present embodiment is that: in order to ensure the stabilizing effect of the vortex-proof and noise-reduction of the current collector, the bending portion 410 defines a bending line 411 on the front cover plate 41, the bending line 411 intersects with a profile defined by the outer periphery of the front cover plate 41 and defines a first bending point 412 and a second bending point 413, a connecting line between the first bending point 412 and the center of the air inlet 44 is a first straight line L1, a connecting line between the second bending point 413 and the center of the air inlet 44 is a second straight line L2, an included angle formed by the intersection of the first straight line L1 and the second straight line L2 is β, and an angle corresponding to the radian of the noise reduction fin 30 is α, wherein α is greater than or equal to β.

After the collector is assembled in place, the noise reduction plate 30 extends into the impeller 50, and a gap 45 is formed between the noise reduction plate and a curved surface defined by the inner diameter of the impeller 50, specifically, a distance between an outer wall surface of the noise reduction plate 30 and the curved surface defined by the inner diameter of the impeller 50 is denoted by m, wherein m is greater than or equal to 4mm and less than or equal to 8mm, and preferably, m is greater than or equal to 6 mm.

In order to match the noise reduction fins 30 with the impeller 50 of the centrifugal fan, avoid that the noise reduction fins 30 and the impeller 50 are overlapped less axially to achieve a stable flow field, and avoid that the noise reduction fins 30 extend into the impeller 50 too much to affect the fan performance, the height of the blades 53 of the impeller 50 is denoted by b, and the axial dimension of the noise reduction fins 30 of the collector on the central axis O is L, wherein L/b is 0.1 or more and 0.15 or less, and preferably L/b is 0.12.

On the basis of the above embodiments, other embodiments can be obtained by replacing and improving the related technical features. For example, the noise reduction fins 30 of the present embodiment may extend in a direction parallel to the central axis O of the stationary ring 10, or may be inclined radially inward or radially outward along the central axis O of the stationary ring 10.

Claims (11)

1. A collector for a centrifugal fan, comprising:

a stationary ring (10);

the flow guide part (20) is connected to the inner side of the fixed ring (10) and is provided with an inlet end (23) and an outlet end (24) which are opposite to each other in the oil smoke flowing direction;

the method is characterized in that: at least part of the periphery of the outlet end (24) of the flow guide part (20) is provided with noise reduction sheets (30) formed by extending along the flow direction of the oil smoke, and noise reduction holes (33) are distributed on the noise reduction sheets (30).

2. The collector for a centrifugal fan according to claim 1, wherein: the flow guide part (20) comprises a first flow guide part (21) extending from the inner side of the fixing ring (10) radially inwards and bending and protruding against the oil smoke flowing direction, and a second flow guide part (22) extending from the inner side of the first flow guide part (21) along the oil smoke flowing direction, and the noise reduction sheet (30) is connected to the second flow guide part (22).

3. The collector for a centrifugal fan according to claim 1, wherein: the noise reduction sheet (30) is an arc sheet body formed by extending a section of the periphery of the outlet end (24) of the flow guide part (20) along the flowing direction of oil smoke, the corresponding angle of the radian of the noise reduction sheet (30) is alpha, and the alpha is more than or equal to 30 degrees and less than or equal to 120 degrees.

4. The collector for a centrifugal fan according to claim 1, wherein: the noise reduction sheet (30) is provided with a front edge (31) far away from the flow guide part (20) and two opposite side edges (32) in the circumferential direction, the distance between the two side edges (32) is gradually reduced along the oil fume flowing direction, the middle area of the noise reduction sheet (30) is a conical surface, the vertex angle of the conical surface is theta, and the theta is larger than or equal to 30 degrees and smaller than or equal to 90 degrees.

5. The collector for the centrifugal fan according to any one of claims 1 to 4, wherein: the diameter of the noise reduction hole (33) is d, and the value range is as follows: d is more than or equal to 1.5mm and less than or equal to 3mm, each noise reduction hole (33) is uniformly arranged on the noise reduction sheet, the distance between every two adjacent noise reduction holes (33) is s, and the value range is as follows: s is more than or equal to 4mm and less than or equal to 6 mm.

6. The collector for the centrifugal fan according to any one of claims 1 to 4, wherein: the noise reduction sheet (30) and the flow guide part (20) are designed into a whole.

7. A multi-wing centrifugal fan using the collector of any one of claims 1 to 6, wherein: the noise reduction device comprises a volute (40) with an air inlet (44), an impeller (50) arranged in the volute (40), and a current collector, wherein the current collector is arranged at the air inlet (44) of the volute (40), and the noise reduction sheet (30) extends into the impeller (50) and has a gap (45) with a curved surface defined by the inner diameter of the impeller (50).

8. The multi-wing centrifugal fan of claim 7, wherein: the impeller (50) comprises a front disc (51), a rear disc (52) and blades (53) arranged between the front disc (51) and the rear disc (52) along the circumferential direction, the height of each blade (53) is b, the axial size of each noise reduction sheet (30) of the current collector on the central axis (O) of the fixed ring (10) is L, and L/b is more than or equal to 0.1 and less than or equal to 0.15.

9. The multi-wing centrifugal fan of claim 7, wherein: the distance between the outer wall surface of the noise reduction sheet (30) and the curved surface defined by the inner diameter of the impeller (50) is marked as m, wherein m is more than or equal to 4mm and less than or equal to 8 mm.

10. The multi-wing centrifugal fan of claim 7, wherein: the volute casing (40) include front shroud (41), back shroud (42) and connect rampart (43) between front shroud (41) and back shroud (42), the lower part of front shroud (41) is formed with bend (410) towards back shroud (42) direction slope, the piece of making an uproar (30) of current collector do one section of extending the circular arc lamellar body that forms along the oil smoke flow direction on the periphery of water conservancy diversion portion (20) exit end (24), the piece of making an uproar (30) are in the footpath of current collector with the bend (410) of volute casing (40) are corresponding.

11. The multi-wing centrifugal fan of claim 10, wherein: the bending part (410) defines a bending line (411) on the front cover plate (41), the bending line (411) intersects with a molded line defined by the outer periphery of the front cover plate (41) and defines a first bending point (412) and a second bending point (413), a connecting line between the first bending point (412) and the center of the air inlet (44) is a first straight line (L1), a connecting line between the second bending point (413) and the center of the air inlet (44) is a second straight line (L2), an included angle formed by intersection of the first straight line (L1) and the second straight line (L2) is beta, an angle corresponding to the radian of the noise reduction sheet (30) is alpha, and alpha is larger than or equal to beta.

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