CN201116543Y - Centrifugal fan volute - Google Patents

Abstract

The utility model discloses a volute of a centrifugal fan, which solves the problem of high rotational noise of the existing centrifugal fan. The volute of the centrifugal fan adopts the following structure: the volute (1) is provided with an impeller (2), and the volute (1) includes a front plate (3), a side plate (12), a bottom plate (11) and a volute tongue (4) , the front plate (3) is provided with an air inlet (5), the bottom plate (11) is opposite to the front plate (3), and the longitudinal symmetrical plane (8) of the volute tongue (4) has an included angle with the axis line (6) of the impeller (a), the intersection line (9) between the longitudinal symmetry plane (8) and the outer surface of the volute tongue (4) is a curve, and the gap between the volute tongue near the air inlet (5) or the two ends of the bottom plate (11) is smaller than that in the middle Tongue gap, the radius of the volute tongue at the end (5) near the air inlet is smaller than the radius of the volute tongue at the end near the bottom plate (11), which achieves the effect of reducing the noise of the centrifugal fan without increasing the cost and ensuring that the air volume and efficiency of the fan are not reduced. Mainly used in multi-blade centrifugal fans.

Description

Centrifugal fan volute

technical field

The utility model relates to a centrifugal fan volute, in particular to a centrifugal fan volute with an inclined volute tongue.

Background technique

The role of the centrifugal fan volute is to concentrate and guide the gas coming out of the impeller, and to convert part of the kinetic energy of the gas into static pressure. When the impeller rotates, the periodic collision between the airflow brought by the impeller and the volute tongue and the airflow periodically passing through the minimum gap between the blade and the volute tongue will generate a periodic rotational noise. The traditional centrifugal fan volute mostly adopts the form of straight volute tongue and constant volute radius. For example, the centrifugal fan volute used in air conditioners has such a structure: the volute is equipped with an impeller, and the volute includes a front plate and a side plate. , bottom plate and volute tongue, the front plate is provided with an air inlet, the bottom plate is opposite to the front plate, the axis of the impeller is perpendicular to the plane where the bottom plate is located, and the longitudinal symmetrical plane of the volute tongue is parallel to the axis of the impeller. The longitudinal symmetrical plane refers to the The tongue is divided into two symmetrical parts along the direction from one end of the air inlet to the bottom plate. The volute tongue gap of this structure means that the minimum gap between the outer circumference of the impeller, that is, the minimum gap between the tip of the blade and the volute tongue, does not change along the direction of the impeller axis on a section perpendicular to the axis of the impeller. Therefore, since the volute tongue gap is equal in the entire axial direction, the noise of the same frequency is superimposed, resulting in periodic peak noise, resulting in relatively high rotational noise of the centrifugal fan with this structure. The announcement number is CN2359508 and the publication date is January 19, 2000. The Chinese utility model patent "Centrifugal Fan Volute" discloses a centrifugal fan volute that reduces the rotational noise of the centrifugal fan. The patent uses a volute tongue and/or volute The structure of the inner wall of the casing "inclined outward" relative to the axis of the impeller makes the gap between the impeller and the volute tongue change along the axial direction of the impeller, thereby reducing the rotational noise of the centrifugal fan. The longitudinal symmetry plane of this inclined volute tongue is still parallel to the axis of the impeller.

Utility model content

In order to overcome the disadvantage that the structure of the existing centrifugal fan volute still produces relatively large rotational noise, the technical problem to be solved by the utility model is to provide a centrifugal fan volute that can further reduce the rotational noise.

The technical solution adopted by the utility model to solve the technical problems is: centrifugal fan volute, the volute is provided with an impeller, the volute includes a front plate, a side plate, a bottom plate and a volute tongue, the front plate is provided with an air inlet, the bottom plate and The front plate is opposite, and the longitudinal symmetrical plane of the volute tongue has an included angle with the axis line of the impeller.

The beneficial effects of the utility model are: since the longitudinal symmetrical plane of the volute tongue has an included angle with the axis line of the impeller, that is, the clearance of the volute tongue changes in both the axial and radial directions of the impeller, which will cause the blade to rotate between different positions. There is less noise resonance in the rotation noise, thus more effectively avoiding the periodic peak noise formed by the superposition of rotation noise. At the same time, the structure of variable volute tongue radius and variable volute tongue clearance is adopted to optimize the airflow distribution in the fan, especially reduce the outlet return flow and internal vortex of the centrifugal fan, and effectively reduce the impact of the volute tongue on the airflow on the basis of reducing the rotation noise. The resistance can reduce the flow loss and improve the efficiency of the fan.

Description of drawings

Fig. 1 is a schematic diagram of a centrifugal fan volute adopting an inclined volute tongue of the utility model.

Fig. 2 is a schematic diagram of a centrifugal fan volute with variable volute tongue radius and variable volute tongue clearance of the utility model.

In the figure, 1-volute, 2-impeller, 3-front plate, 4-volute tongue, 5-air inlet, 6-impeller axis, 7-installation hole, 8-longitudinal symmetry plane, 9-intersection Line, 10-blade, 11-bottom plate, 12-side plate. a-angle, b-cochlear tongue gap.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in Figures 1 and 2, the centrifugal fan volute of the present utility model is provided with an impeller 2 in the volute 1, and the volute 1 includes a front plate 3, a side plate 12, a bottom plate 11 and a volute tongue 4, and on the front plate 3 An air inlet 5 is provided, the bottom plate 11 is opposite to the front plate 3, and the longitudinal symmetrical plane 8 of the volute tongue 4 has an included angle a with the axis 6 of the impeller. Since the worm tongue 4 is deflected in both the axial and radial directions of the impeller relative to the impeller axis 6, that is, the gap between the worm tongue 4 and the impeller 2 changes in both the axial and radial directions of the impeller 2, it will This makes the rotation noise between the different positions of the blade 10 and the volute tongue 4 less prone to noise resonance, thereby more effectively avoiding the periodic peak noise formed by the superposition of the rotation noise.

Considering the influence of the airflow at the air inlet, the inclination direction of the longitudinal symmetry plane 8 is: the minimum distance between the volute tongue 4 close to the front plate 3 and the side plate 12 is smaller than the minimum distance between the volute tongue 4 close to the bottom plate 11 and the side plate 12 , to reduce noise.

According to relevant calculations, the value of the included angle a is more suitable between 5° and 60°.

In addition, the intersection line 9 between the longitudinal symmetry plane 8 of the volute tongue 4 and the outer surface of the volute tongue can be further designed as a curve, and the volute tongue gap near the air inlet 5 or the two ends near the bottom plate 11 is smaller than the volute tongue gap in the middle. That is to say, the structure of variable volute tongue gap is adopted to optimize the airflow distribution in the fan, especially to reduce the return flow of the centrifugal fan outlet and the internal vortex, and to increase the effective air volume of the centrifugal fan.

Considering the influence of the airflow at the air inlet, the volute tongue gap near the air inlet 5 is smaller than the volute tongue gap near the bottom plate 11 .

From the perspective of gradual change to reduce noise and resistance, the volute tongue gap changes uniformly.

Furthermore, a method of changing the radius of the volute tongue can be adopted: the volute tongue 4 is designed to have a gradually changing radius of the volute tongue, and the radius of the volute tongue near the end of the air inlet 5 is smaller than the radius of the volute tongue near the end of the bottom plate 11 . The radius of the tongue increases or decreases gradually from one end of the tongue to the other end of the tongue. The above method of changing the radius of the volute tongue further reduces the resistance of the volute tongue to the airflow, thereby achieving the effect of reducing flow loss and improving the efficiency of the fan.

Considering the need for uniform resistance changes to further reduce noise, the radius of the volute tongue changes uniformly.

Embodiment: As shown in Figure 2, the centrifugal fan volute of the present utility model is provided with an impeller 2 inside the volute 1, and the volute 1 includes a front plate 3, a side plate 12, a bottom plate 11 and a volute tongue 4, and on the front plate 3 There is an air inlet 5, the bottom plate 11 is opposite to the front plate 3, and the bottom plate 11 is provided with a mounting hole 7, and there is an angle a between the longitudinal symmetrical plane 8 of the volute tongue 4 and the axis line 6 of the impeller, and the longitudinal symmetry of the volute tongue 4 The intersection line 9 between the surface 8 and the outer surface of the volute tongue is a curve, and the volute tongue gap near the air inlet 5 or the two ends close to the bottom plate 11 is smaller than the volute tongue gap in the middle, and at the same time, the radius of the volute tongue near the air inlet 5 is smaller than that near the bottom plate 11 Tongue radius at one end.

The volute of the centrifugal fan can reduce noise by 6% and increase air volume by 7%.

Claims (8)

1. Centrifugal fan volute, volute (1) is provided with impeller (2), volute (1) includes front plate (3), side plate (12), bottom plate (11) and volute tongue (4), front An air inlet (5) is arranged on the plate (3), and the bottom plate (11) is opposite to the front plate (3). It is characterized in that: the longitudinal symmetrical plane (8) of the volute tongue (4) has Angle (a). 2. The centrifugal fan volute according to claim 1, characterized in that: the inclination direction of the longitudinal symmetry plane (8) is: between the volute tongue (4) close to the front plate (3) and the side plate (12) The minimum distance is less than the minimum distance between the volute tongue (4) close to the bottom plate (11) and the side plate (12). 3. The centrifugal fan volute as claimed in claim 2, characterized in that: the included angle (a) is 5°～60°. 4. The centrifugal fan volute according to claim 1, 2 or 3, characterized in that: the intersection line (9) between the longitudinal symmetry plane (8) and the outer surface of the volute tongue (4) is a curve, and is close to the air inlet ( 5) or the volute tongue gap at the two ends near the base plate (11) is smaller than the volute tongue gap in the middle. 5. The centrifugal fan volute according to claim 4, characterized in that: the volute tongue gap near the air inlet (5) is smaller than the volute tongue gap near the bottom plate (11). 6. The centrifugal fan volute as claimed in claim 4, characterized in that: the volute tongue gap changes uniformly. 7. The centrifugal fan volute according to claim 4, characterized in that: the radius of the volute tongue near the air inlet (5) is smaller than the radius of the volute tongue near the bottom plate (11). 8. The centrifugal fan volute as claimed in claim 7, wherein the radius of the volute tongue changes uniformly.

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