CN116265764A

CN116265764A - Centrifugal fan and smoke exhaust ventilator

Info

Publication number: CN116265764A
Application number: CN202111575097.5A
Authority: CN
Inventors: 姚杨; 李业强; 陈鹏; 胡斯特
Original assignee: Midea Group Co Ltd; Guangdong Midea White Goods Technology Innovation Center Co Ltd
Current assignee: Midea Group Co Ltd; Guangdong Midea White Goods Technology Innovation Center Co Ltd
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2023-06-20

Abstract

The application discloses centrifugal fan and smoke ventilator, wherein, centrifugal fan includes spiral case, wind wheel and restraines the flow subassembly. The volute is provided with a volute inlet and a volute outlet, and a volute tongue is formed at a position close to the volute outlet; the wind wheel is arranged in the volute; the flow restraining component is arranged at the volute tongue, and a flow restraining channel for air flow to pass through is arranged in the flow restraining component. The centrifugal fan can reduce noise when the centrifugal fan operates.

Description

Centrifugal fan and smoke exhaust ventilator

Technical Field

The application relates to the technical field of smoke exhaust ventilator, in particular to a centrifugal fan and a smoke exhaust ventilator.

Background

Centrifugal fans are widely used in range hoods as a component for an air duct. When the centrifugal fan works, air flow enters from the volute inlet of the centrifugal fan, and the air flow is blown out from the volute outlet along the rotating direction of the air wheel when the air wheel rotates. The volute tongue near the volute outlet of the centrifugal fan can be used for guiding airflow to blow out to the volute outlet of the centrifugal fan. However, the air flow thrown out by the impeller has strong impact on the volute tongue, strong vortex flow can be generated by the air flow at the volute tongue, and the air flows can be impacted, so that the centrifugal fan has high noise in operation.

Disclosure of Invention

The main purpose of this application is to propose a centrifugal fan, aims at reducing the noise when centrifugal fan operates.

In order to achieve the above purpose, the centrifugal fan provided by the application comprises a volute, a wind wheel and a flow inhibition assembly. The volute is provided with a volute inlet and a volute outlet, and a volute tongue is formed at a position close to the volute outlet; the wind wheel is arranged in the volute; the flow restraining component is arranged at the volute tongue, and a flow restraining channel for air flow to pass through is arranged in the flow restraining component.

Optionally, the volute tongue comprises a drainage part facing the wind wheel, a diversion part positioned at one side of the outlet of the volute, and a corner part connecting the drainage part and the diversion part; the flow suppression assembly is disposed at the corner.

Optionally, the flow suppression assembly comprises a support and a turbulence net; wherein the support is provided with the flow inhibiting channel; the turbulence net is arranged at the inlet end of the flow inhibition channel and is arranged at intervals with the volute tongue.

Optionally, the support is further provided with a first open surface and a second open surface corresponding to the outlet end of the flow inhibiting channel; the first open face opens in a direction toward the volute outlet; the second open face is open toward the direction of the wind wheel.

Optionally, a third open surface corresponding to the outlet end of the flow inhibiting channel is further arranged on one side of the support, which is close to the volute tongue, and the third open surface is located between the turbulence net and the volute tongue.

Optionally, the bracket comprises two mounting plates arranged at intervals along the axial direction of the wind wheel; two ends of the turbulence net are respectively connected with two mounting plates, so that the support forms a first open surface and a second open surface on two sides of the turbulence net respectively, and forms a third open surface on the rear side of the turbulence net.

Optionally, the corner portion has a closest point to the turbulence net having a tangent, the angle between the plane of the turbulence net and the tangent being no more than 10 °.

Optionally, the wind wheel comprises a plurality of blades which are arranged at intervals along the same circumference, the distance between any two adjacent blades is D, and the shortest distance between the turbulence net and the nearest point is D1, and 1.3D is less than D1 and less than 2.1D.

Optionally, the shortest distance between the turbulence net and the wind wheel is D2,1.6D < D2 < 2.3D.

Optionally, a projection surface of the turbulence net towards the corner portion covers the corner portion.

Optionally, the mesh number of the turbulent mesh is 15 mesh to 50 mesh.

Optionally, the bracket and the volute tongue are formed in a split manner; or, the bracket and the volute tongue are integrally formed.

The application also provides a smoke ventilator, smoke ventilator includes centrifugal fan. The centrifugal fan comprises a volute, a wind wheel and a flow inhibition assembly. The volute is provided with a volute inlet and a volute outlet, and a volute tongue is formed at a position close to the volute outlet; the wind wheel is arranged in the volute; the flow restraining component is arranged at the volute tongue, and a flow restraining channel for air flow to pass through is arranged in the flow restraining component.

According to the technical scheme, the flow inhibition assembly is arranged at the volute tongue of the centrifugal fan, so that when the centrifugal fan works, air flow blown to the volute tongue passes through the flow inhibition assembly first and then flows out through the flow inhibition channel of the flow inhibition assembly. The flow inhibiting assembly can impact air flow to the volute tongue to generate larger vortex groups and break the larger vortex groups into smaller vortex groups, so that the strength of the vortex groups is reduced, and noise generated by impact of the air flow on the volute tongue can be further reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained from the structures shown in these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1 is a schematic diagram of an embodiment of a centrifugal fan according to the present application;

FIG. 2 is an exploded view of the centrifugal fan of FIG. 1;

FIG. 3 is a schematic diagram of the structure of FIG. 1 from another perspective;

FIG. 4 is a cross-sectional view taken along line I-I in FIG. 3;

FIG. 5 is an enlarged view of FIG. 4 at A;

FIG. 6 is a schematic view of a portion of the structure of FIG. 1;

FIG. 7 is a schematic view of an embodiment of a flow suppression assembly of the present application;

FIG. 8 is a schematic view of another embodiment of a flow suppression assembly of the present application;

fig. 9 is a graph comparing noise spectra of a centrifugal fan of the present application with that of a conventional centrifugal fan.

Reference numerals illustrate:

reference numerals	Name of the name	Reference numerals	Name of the name
				10	Centrifugal fan	210	Blade
100	Volute casing	300	Flow inhibiting assembly
				110	Volute inlet	310	Support frame
120	Volute outlet	311	Mounting plate
				130	Volute tongue	320	Turbulent flow net
131	Drainage part	330	A first open face
				132	Flow guiding part	340	A second open face
133	Corner portion	350	Third open face
				140	Air duct coaming	400	Flow inhibiting channel
150	Cover plate	500	Adapter piece
				200	Wind wheel

The realization, functional characteristics and advantages of the present application will be further described with reference to the embodiments, referring to the attached drawings.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

It should be noted that, in the embodiment of the present application, directional indications (such as up, down, left, right, front, and rear … …) are referred to, and the directional indications are merely used to explain the relative positional relationship, movement conditions, and the like between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if the meaning of "and/or" is presented throughout this document, it is intended to include three schemes in parallel, taking "a and/or B" as an example, including a scheme, or B scheme, or a scheme where a and B meet simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present application.

The application provides an embodiment of centrifugal fan, the noise when centrifugal fan can reduce the operation to improve user's use impression. The centrifugal fan can be installed in household appliances such as a smoke extractor, an air purifier, a mobile air conditioner, a dehumidifier and the like for use. In the following embodiments, a range hood is mainly described as an example, and other types of household appliances may be referred to for implementation.

Referring to fig. 1 and 2, in an embodiment of the present application, the centrifugal fan 10 includes a volute 100, a wind wheel 200, and a flow suppression assembly 300. The scroll 100 is provided with a scroll inlet 110 and a scroll outlet 120, and the scroll 100 is formed with a scroll tongue 130 at a position near the scroll outlet 120; the wind wheel 200 is installed in the volute 100; the flow suppressing assembly 300 is disposed at the volute tongue 130, and a flow suppressing channel 400 through which the air flows is disposed inside the flow suppressing assembly 300.

Specifically, the volute 100 includes an air duct shroud 140 and two cover plates 150 that cover two sides of the air duct shroud 140, where the air duct shroud 140 and the two cover plates 150 enclose a cavity in which the wind turbine 200 is mounted. Two volute inlets 110 are respectively formed in two cover plates 150 of the volute 100, a volute outlet 120 is formed in the volute 100, and when the centrifugal fan 10 works, air flow enters from the volute inlets 110 located on the two cover plates 150 and is blown out from the volute outlet 120 under the action of the wind wheel 200. The two volute inlets 110 may further increase the amount of airflow into the blower 10.

The volute 100 is also formed with a volute tongue 130 near the volute outlet 120, the volute tongue 130 resembling a tongue "structure that allows a portion of the airflow to circulate within the volute 100. When the blades 210 of the rotating rotor 200 draw air, the airflow at the volute outlet 120 passes near the volute tongue 130, and the volute tongue 130 splits the airflow passing through it into two: most of the airflow flows along the air outlet passage in the volute 100 to the volute outlet 120; a small part of the air flow flows back into the volute 100 through the gap between the volute tongue 130 and the wind wheel 200, and returns to the volute tongue 130 to participate in new diversion after rotating along with the wind wheel 200 in the volute 100 for a circle.

The flow suppressing assembly 300 is disposed near the volute tongue 130, and the flow suppressing assembly 300 may be integrally formed with the volute tongue 130 or may be disposed near the volute tongue 130 alone, which is not particularly limited. The flow suppressing assembly 300 is formed with a flow suppressing channel 400 through which the air flows, when the centrifugal fan 10 works, the wind wheel 200 rotates to drive the air flow to flow, and when the air flow flows to the volute tongue 130, the air flow firstly passes through the flow suppressing assembly 300, then flows to the volute tongue 130 through the flow suppressing channel 400 of the flow suppressing assembly 300, and finally is split by the volute tongue 130. When the airflow in the volute 100 impacts the volute tongue 130, a larger vortex is usually generated, the vortex collides with other airflows in the air duct to generate larger noise, the flow inhibition assembly 300 can change the larger vortex group into a smaller vortex group, the strength of the vortex group is reduced, and thus the noise of the centrifugal fan 10 in operation is reduced, and meanwhile, when the airflow passes through the flow inhibition assembly 300, the flow speed of the airflow is further slowed down, so that the noise reduction effect is achieved.

According to the technical scheme, the flow suppressing assembly 300 is arranged at the volute tongue 130 of the centrifugal fan 10, so that when the centrifugal fan 10 works, air flow blown to the volute tongue 130 passes through the flow suppressing assembly 300 first and then flows out through the flow suppressing channel 400 of the flow suppressing assembly 300. The flow suppression assembly 300 may break up larger and smaller vortex clusters generated by the airflow striking the volute tongue 130, thereby reducing the strength of the vortex clusters, and thus, may further reduce the noise generated by the airflow striking the volute tongue 130.

Referring to fig. 5, 7 and 8, in one embodiment, the volute tongue 130 includes a guiding portion 131 facing the wind wheel 200, a guiding portion 132 located at one side of the volute outlet 120, and a corner portion 133 connecting the guiding portion 131 and the guiding portion 132; the flow suppression assembly 300 is disposed at the corner 133.

Specifically, when the centrifugal fan 10 is in operation, the wind wheel 200 rotates at a high speed, and air enters the interior of the scroll casing 100 from the scroll casing inlet 110, and then the air flow is blown out through the scroll casing outlet 120 along the direction in which the wind wheel 200 rotates. When the airflow within the volute 100 flows to the volute tongue 130 near the volute outlet 120, the volute tongue 130 splits the airflow passing therethrough into two: most of the airflow flows along the air outlet passage in the volute 100 to the volute outlet 120; a small portion of the airflow flows back into the volute 100 through the gap between the volute tongue 130 and the wind wheel 200. Wherein, most of the air flow is blown out from the volute outlet 120 along the extending direction of the guiding part 132, and the guiding part 132 extends obliquely to the direction of the volute outlet 120; a small portion of the airflow continues to flow along the drainage portion 131 and flows into the volute 100, and returns to the volute tongue 130 to participate in new diversion after the volute 100 rotates along with the wind wheel 200 for one circle.

The volute tongue 130 is similar to a tongue "structure, and the head of the volute tongue 130 has a corner 133 that can split the airflow flowing to the volute tongue 130, so that a portion of the airflow can circulate in the volute 100. The volute tongue 130 can be integrally formed with the volute 100, so that a separate die for the volute tongue 130 is not required, the die design can be reduced, the manufacturing process of the centrifugal fan 10 is reduced, and the production efficiency is effectively improved. The volute tongue 130 may also be separately disposed with the volute 100, and the volute tongue 130 may be fixedly installed near the volute outlet 120 by means of screws, welding or fastening, so as to split the airflow flowing to the volute tongue 130. In particular, in this embodiment, the volute tongue 130 is disposed separately from the volute casing 100, and the volute tongue 130 is fixedly mounted on the air duct shroud 140 of the volute casing 100 by screws.

Referring to fig. 7, in one embodiment, a flow suppression assembly 300 includes a support 310 and a turbulent screen 320; the support 310 is provided with a flow-inhibiting channel 400; the turbulence net 320 is disposed at the inlet end of the flow-inhibiting channel 400 and is spaced apart from the volute tongue 130.

That is, the turbulence net 320 is mounted on the support 310, the turbulence net 320 is fixedly mounted on the volute tongue 130 through the support 310, the support 310 can be fixedly mounted on the volute tongue 130 through screws, welding, pasting and the like, and can also be directly integrated with the volute tongue 130 in the production process. A flow-inhibiting channel 400 is also formed between the turbulence net 320 and the volute tongue 130, and when the airflow in the volute 100 blows toward the volute tongue 130, the airflow first passes through the turbulence net 320, then enters the flow-inhibiting channel 400, and finally blows toward the volute tongue 130. The airflow will flow with the

flow guide

131 and 132 into the volute 100 and the volute outlet 120, respectively. The material of the turbulence net 320 may be stainless steel wire or nylon wire, which is not particularly limited herein, and may be selected according to the actual needs of the user. The turbulence net 320 breaks up larger vortex clusters created at the volute tongue 130, thereby reducing the impact noise created by the flow of gas at the volute tongue 130.

To verify the noise reduction effect of the centrifugal fan 10 in both the case of using the flow suppression assembly 300 and the case of not using the flow suppression assembly 300, the whole range hood and the fan unit were tested respectively. Through testing, according to the analysis of the test data, the following steps are obtained: for the whole range hood, compared with the whole range hood without the flow inhibiting assembly 300, the noise value of the whole range hood with the flow inhibiting assembly 300 is reduced by 0.8dB; for the fan unit, when the fan flow is 18m3/min, the noise value of the fan unit using the flow suppression assembly 300 is reduced by 1.0dB compared with that of the fan unit not using the flow suppression assembly 300. It can be seen that the noise is significantly reduced in the same product relative to the product to which the flow suppression assembly 300 is applied.

Referring to fig. 5, in an embodiment, the support 310 is further provided with a first open surface 330 and a second open surface 340 corresponding to the outlet end of the flow-inhibiting channel 400; the first open face 330 opens in the direction of the volute outlet 120; the second open surface 340 opens in the direction of the wind rotor 200. Specifically, after the airflow flowing toward the volute tongue 130 enters the flow suppressing channel 400, most of the airflow flows out of the first open face 330 and flows toward the volute outlet 120, and a small portion of the airflow flows out of the second open face 340 and flows toward the volute 100, thereby participating in the next diversion of the airflow at the volute tongue 130.

Further, a third open surface 350 corresponding to the outlet end of the flow-suppressing channel 400 is further provided on the side of the support 310 near the volute tongue 130, and the third open surface 350 is located between the turbulent web 320 and the volute tongue 130. Specifically, the third open surface 350 is located between the turbulent web 320 and the volute tongue 130, and the support 310 is provided with the third open surface 350 facing the direction of the volute tongue 130, so that the airflow can directly flow to the volute tongue 130 and respectively flow to the volute 100 and the volute outlet 120 under the action of the drainage portion 131 and the drainage portion 132 of the volute tongue 130.

Referring to fig. 7 and 8, it should be noted that the bracket 310 includes two mounting plates 311 spaced apart along the axial direction of the wind wheel 200; two mounting plates 311 are respectively connected to both ends of the turbulence net 320 such that the supporter 310 forms a first open surface 330 and a second open surface 340 on both sides of the turbulence net 320, respectively, and a third open surface 350 on the rear side of the turbulence net 320. Specifically, the number of the mounting plates 311 is two, and the mounting plates are respectively located at two ends of the turbulence net 320 and are disposed near the cover plate 150 of the volute 100. The mounting plates 311 have four sides arranged opposite to each other, and the turbulence net 320 is arranged on one side of the two mounting plates 311 on the same side. The first open face 330 and the second open face 340 are formed by two sides adjacent to the side on which the turbulent web 320 is mounted, and the third open face 350 is formed by the side opposite to the side on which the turbulent web 320 is mounted.

Referring to fig. 4 and 5, it is considered that the airflow has a certain direction when flowing in the volute 100, and the airflow generally flows along the direction in which the impeller 200 rotates. When the airflow in the volute 100 flows to the volute outlet 120, most of the airflow directly flows out of the volute outlet 120, and a small part of the airflow flows to the volute tongue 130 for diversion. The flow suppression assembly 300 disposed adjacent the volute tongue 130 may change a larger vortex lump passing therethrough into a smaller vortex lump, reducing the intensity of the vortex lump, and thus reducing noise when the centrifugal fan 10 is operated. Accordingly, the airflow flowing toward the volute tongue 130 should be able to pass through the turbulent web 320 at a suitable angle and then blow toward the volute tongue 130.

In view of this, in order to solve this problem, a tangent line is optionally disposed between the corner 133 of the volute tongue 130 and the closest point of the turbulent net 320, and it should be noted that the tangent line is a virtual tangent line for describing the angle at which the turbulent net 320 is placed at the volute tongue 130, and the included angle between the plane of the turbulent net 320 and the tangent line is not greater than 10 °, so that a better over-wind effect can be achieved, so that most of the airflow flowing toward the volute tongue 130 may pass through the turbulent net 320 before flowing toward the volute tongue 130.

Referring to fig. 5, in one embodiment, the projected surface of the turbulent web 320 toward the corner 133 covers the corner 133. The corner portion 133 has a first boundary line connected to the flow guiding portion 131 and a second boundary line connected to the flow guiding portion 132, and the width of the corner portion 133 is the distance between the first boundary line and the second boundary line. The width of the turbulence net 320 should be greater than the width of the corner 133. As shown in fig. 5, B is represented in the figure as the width of the turbulent web 320. In this manner, the projected surface of the turbulent web 320 toward the corner portion 133 completely covers the corner portion 133. Since the drainage portion 131 and the diversion portion 132 extend obliquely in a direction away from the turbulent flow net 320, in order to facilitate the air flow to pass through the volute tongue 130 smoothly, and flow into the volute 100 and the volute outlet 120 respectively under the action of the drainage portion 131 and the diversion portion 132, the width B of the turbulent flow net 320 is set to be larger than the width of the corner portion 133, so that the air flow can flow out smoothly from two sides of the corner portion 133 when flowing to the volute tongue 130, and the situations of unsmooth air flow, excessive swirling air flow and the like caused by the too wide corner portion 133 are avoided.

Referring to fig. 4 to 6, in an embodiment, the wind wheel 200 includes a plurality of blades 210, a space between any two blades 210 is D, and a shortest distance between the turbulence net 320 and the corner 133 is D1,1.3D < D1 < 2.1D. Further, the shortest distance between the turbulence net 320 and the wind wheel 200 is D2,1.6D < D2 < 2.3D.

Specifically, the installation position of the turbulence net 320 is determined according to the structure of the centrifugal fan 10 and the actual operation state of the centrifugal fan 10. Experimental tests have found that by adjusting the distance between d1 and d2, a large variation in the noise generated by the centrifugal fan 10 during operation will result. If the distance between d1 and d2 is too large, the location of the turbulence net 320 will go deep into the high velocity gas flow region at the volute outlet 120, thus creating significant resistance to gas flow, affecting the performance of the centrifugal fan 10; if the distance d1 is too small, the turbulence net 320 is too close to the volute tongue 130 to have a significant effect on the vortex mass; if the distance d2 is too small, then the turbulence net 320 is too close to the wind wheel 200, and the turbulence net 320 will interfere strongly with the exit wake of the wind wheel 200, thus creating significant frequency noise as the blades 210 pass through the turbulence net 320. Typically, the noise level when the centrifugal fan 10 is not using the flow suppression assembly 300 is 58.2dB. The specific test process is as follows:

the pitch D between the blades 210 on the rotor 200 used for the test was set to 14.6mm, and first, the width b=20 mm of the fixed turbulence net 320, the distance d2=30 mm of the turbulence net 320 from the rotor 200 was measured as follows:

TABLE 1-1 turbulence network for different d1, measured parameters

Turbulence net width (mm)	Distance to the volute tongue (mm)	Distance to wind wheel (mm)	Noise (dB)
				20	15	30	58.0
20	19	30	57.5
				20	23	30	57.3
20	27	30	57.3
				20	30	30	57.6

As can be seen from the above table data, the noise reduction effect is more remarkable when the distance between the turbulence net 320 and the volute tongue 130 is 19 mm-30 mm, that is, d1=19 mm-30 mm, and the requirements of 1.3D < D1 < 2.1D are satisfied under the conditions that the width of the turbulence net 320 is the same and the distance between the turbulence net 320 and the wind wheel 200 is the same.

Second, the width b=20 mm of the fixed turbulence net 320, the distance d1=23 mm of the turbulence net 320 from the volute tongue 130, and the measured data are as follows:

tables 1-2. Turbulence net for different d2, measured parameters

Turbulence net width (mm)	Distance to the volute tongue (mm)	Distance to wind wheel (mm)	Noise (dB)
				20	23	20	57.9
20	23	24	57.6
				20	23	28	57.3
20	23	32	57.4
				20	23	36	57.8

As can be seen from the above table data, the noise reduction effect is more remarkable when the distance between the turbulence net 320 and the wind wheel 200 is 24mm to 32mm, that is, d2=24 mm to 32mm, and the requirements of 1.6D < D2 < 2.3D are satisfied under the conditions that the widths of the turbulence net 320 are the same and the distances between the turbulence net 320 and the volute tongue 130 are the same.

Finally, the width B of the turbulent web 320 was adjusted and the measured data were as follows:

tables 1-3 turbulence net of different B, d, measured parameters

Turbulence net width (mm)	Distance to the volute tongue (mm)	Distance to wind wheel (mm)	Noise (dB)
				10	23	20	57.9
10	23	30	57.4
				20	23	20	57.9
20	23	30	57.3
				30	23	20	58.6
30	23	30	57.8

As can be seen from the above table data, the noise of the centrifugal fan 10 is significantly increased when the width b=30 mm of the turbulence net 320 is equal to the distance between the turbulence net 320 and the volute tongue 130 compared to when b=10 mm and b=20 mm, because the turbulence net 320 is too wide and thus goes deep into the high velocity air flow region at the volute outlet 120, creating significant resistance to the flow of air.

From a combination of the test data in tables 1-1 to 1-3, it can be seen that the turbulence net 320 has the best noise reduction effect on the centrifugal fan 10 when d1=19 mm to 30mm and d2=24 mm to 32mm in the case of a=14.6mm. That is, the distance between any two blades 210 on the wind wheel 200 in the centrifugal fan 10 is D, the shortest distance between the turbulence net 320 and the corner 133 is D1, the shortest distance between the turbulence net 320 and the wind wheel 200 is D2, and the turbulence net 320 has the best noise reduction effect on the centrifugal fan 10 when 1.3D < D1 < 2D,1.6D < D2 < 2.3D are satisfied.

Referring to fig. 9, fig. 9 further illustrates the effect of turbulence net 320 on the noise frequency bands. In fig. 9, (1) represents BPF (blade passing frequency ) band noise generated by dynamic and static interference of the turbulent web 320, (2) represents broadband noise of 200-400Hz, and (3) represents broadband noise of 1200-1700Hz, and dynamic and static interference refers to the interaction between periodically varying airflow generated by the rotating blades 210 in the wind wheel 200 and the

stationary volute tongue

130, 100. The turbulent flow net 320 does not improve the noise of the BPF frequency band generated by dynamic and static interference obviously, but reduces the broadband noise of 200-400Hz and 1200-1700 Hz. Since these broadband noises are mainly related to pressure pulsations generated by the vortex mass in the volute 100, the test results further demonstrate that the turbulence net 320 is mainly used for breaking up the larger vortex mass, and the control of the larger vortex mass is realized, so as to reduce the noise generated by the centrifugal fan 10 during operation.

In one embodiment, the mesh size of the turbulent web 320 is 15 mesh to 50 mesh. Specifically, the noise reduction effect of the centrifugal fan 10 may also vary due to the aperture and density of the turbulent web 320. Preferably, the mesh size of the turbulent flow net 320 can be 18 mesh, and the stainless steel wire net with 18 mesh or the nylon Long Siwang has better noise reduction effect when being used as the turbulent flow net 320.

There are a variety of designs for the particular type of bracket 310.

Referring to fig. 7, in one embodiment, the bracket 310 and the volute tongue 130 are formed separately. Specifically, the bracket 310 and the volute tongue 130 are formed in a split manner, the bracket 310 in the later stage can be fixedly mounted on the volute 100 by means of screws, welding, pasting, clamping and the like, and meanwhile, the wall thickness of the volute tongue 130 can be made thicker, the wall thickness of the volute tongue 130 is not required to be the same as that of the volute 100, and the structural strength of the volute tongue 130 is further enhanced.

Referring to fig. 8, in another embodiment, the bracket 310 and the volute tongue 130 are integrally formed. By the arrangement, a separate die for the volute tongue 130 is not required, so that the die design can be reduced, the manufacturing process of the centrifugal fan 10 is reduced, the production efficiency is effectively improved, and meanwhile, the trouble of assembling the volute tongue 130 and the volute 100 is avoided.

Specifically, any one of the above embodiments may be selected according to actual needs, and is not particularly limited herein.

Referring to fig. 1-4, in one embodiment, the centrifugal fan 10 further includes an adapter 500, the adapter 500 being disposed at the volute outlet 120. Specifically, the adaptor 500 may be used in conjunction with an exhaust duct to direct the flow of air exiting through the volute outlet 120 out through the exhaust duct. For example, the centrifugal fan 10 may be disposed in a range hood, and one end of an exhaust duct is connected to the adapter 500, and the other end is communicated with an outdoor environment to exhaust the oil smoke sucked by the centrifugal fan 10 to the outside. One end of the adaptor 500 is fixedly installed at the volute outlet 120, and since the volute outlet 120 is square, one end of the adaptor 500 connected with the volute outlet 120 is also square. The other end of the adaptor 500 is used for connecting with an exhaust pipe, so that one end of the adaptor 500 connected with the exhaust pipe is circular. An external thread is further provided on the outer circumferential surface of the end of the adaptor 500 connected to the exhaust pipe, so that the exhaust pipe is screw-coupled to the adaptor 500.

The present application also proposes a range hood comprising a centrifugal fan 10. The specific structure of the centrifugal fan 10 refers to the above embodiments, and since the range hood adopts all the technical solutions of all the embodiments, the range hood at least has all the beneficial effects brought by the technical solutions of the embodiments, and will not be described in detail herein.

The foregoing description is only of the optional embodiments of the present application, and is not intended to limit the scope of the patent application, and all equivalent structural changes made by the specification and drawings of the present application or direct/indirect application in other related technical fields are included in the scope of the patent protection of the present application.

Claims

1. A centrifugal fan, the centrifugal fan comprising:

the spiral case is provided with a spiral case inlet and a spiral case outlet, and a spiral case tongue is formed at a position close to the spiral case outlet;

the wind wheel is arranged in the volute; and

the flow suppression assembly is arranged at the volute tongue, and a flow suppression channel for air flow to pass through is arranged in the flow suppression assembly.

2. The centrifugal fan according to claim 1, wherein the volute tongue includes a flow guiding portion facing the wind wheel, a flow guiding portion located at an outlet side of the volute, and a corner portion connecting the flow guiding portion and the flow guiding portion; the flow suppression assembly is disposed at the corner.

3. The centrifugal fan of claim 2, wherein the flow suppression assembly comprises a support and a turbulence net; wherein the support is provided with the flow inhibiting channel; the turbulence net is arranged at the inlet end of the flow inhibition channel and is arranged at intervals with the volute tongue.

4. The centrifugal fan according to claim 3, wherein the bracket is further provided with a first open face and a second open face corresponding to the outlet end of the flow suppressing passage; the first open face opens in a direction toward the volute outlet; the second open face is open toward the direction of the wind wheel.

5. The centrifugal fan of claim 4, wherein a side of the bracket adjacent to the volute tongue is further provided with a third open face corresponding to the outlet end of the flow-inhibiting passage, the third open face being located between the turbulent flow net and the volute tongue.

6. The centrifugal fan of claim 5, wherein the bracket includes two mounting plates spaced apart along the axis of the rotor; two ends of the turbulence net are respectively connected with two mounting plates, so that the support forms a first open surface and a second open surface on two sides of the turbulence net respectively, and forms a third open surface on the rear side of the turbulence net.

7. The centrifugal fan according to any one of claims 3-6, wherein the corner portion has a closest point of minimum distance from the turbulence net, the closest point having a tangent line, the turbulence net being at an angle of no more than 10 ° between the plane and the tangent line.

8. The centrifugal fan of claim 7, wherein the wind wheel comprises a plurality of blades which are arranged at intervals along the same circumference, the distance between any two adjacent blades is D, the shortest distance between the turbulence net and the nearest point is D1, and 1.3D < D1 < 2.1D.

9. The centrifugal fan of claim 8, wherein the shortest distance between the turbulence net and the wind wheel is D2,1.6D < D2 < 2.3D.

10. The centrifugal fan according to any one of claims 3-6, wherein a projection surface of the turbulence net towards the corner portion covers the corner portion.

11. The centrifugal fan of any of claims 3-6, wherein the turbulence mesh is 15 mesh to 50 mesh in mesh.

12. The centrifugal fan according to any one of claims 3 to 6, wherein the bracket and the volute tongue are formed separately; or, the bracket and the volute tongue are integrally formed.

13. A range hood comprising a centrifugal fan as claimed in any one of claims 1 to 12.