Volute for centrifugal fan, centrifugal fan and range hood

Abstract

The present application relates to the technical field of centrifugal fans and discloses a volute for a centrifugal fan, comprising a volute top plate, a volute enclosure, and a volute bottom plate. The volute enclosure is connected between the volute top plate and the volute bottom plate. The cross-sectional outer peripheral profile of the volute enclosure includes a logarithmic spiral diffusion profile, a logarithmic spiral profile, a volute tongue profile, and a volute tongue diffusion profile that are smoothly connected in counterclockwise order. The logarithmic spiral diffusion profile is a straight line, the logarithmic spiral profile is a gradually expanding spiral profile, the volute tongue profile is a curve, and the volute tongue diffusion profile is a straight line. Air has better flow characteristics within the volute, improving efficiency and reducing noise.

Description

Technical Field

[0001] The present application relates to the technical field of centrifugal fans, for example, to a volute for a centrifugal fan, a centrifugal fan for a range hood, and a range hood. Background Art

[0002] At present, range hoods are important appliances in modern home kitchens. The air volume, air pressure and noise level of the range hood during operation affect the user experience of the product. Therefore, improving the air volume and air pressure of the range hood during operation while reducing its operating noise is also the research and development direction of major manufacturers.

[0003] The multi-blade centrifugal fan is a core component of range hoods, and its performance directly impacts the performance of the range hood. Typically, a multi-blade centrifugal fan consists of two major components: the impeller and the volute. The impeller is located in the flow path within the volute. The design of a traditional centrifugal fan volute ignores the viscosity of the flowing gas and assumes a uniform gas flow along the entire impeller outlet. The volute outlet area is then calculated. However, in actual use, due to gas viscosity and non-uniform airflow at the impeller outlet, the volute outlet area calculated by traditional theory is not optimal. Consequently, significant vortices appear within the volute during operation, generating noise. Summary of the Invention

[0004] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0005] The embodiments of the present disclosure provide a volute for a centrifugal fan, so as to partially solve the technical problem that the existing volute generates obvious noise during operation.

[0006] In some embodiments, the volute for a centrifugal fan includes a volute top plate, a volute enclosure and a volute bottom plate, the volute enclosure is connected between the volute top plate and the volute bottom plate, and the cross-sectional peripheral profile of the volute enclosure includes a logarithmic spiral diffusion profile, a logarithmic spiral profile, a volute tongue profile and a volute tongue diffusion profile that are smoothly connected in a counterclockwise order; wherein, the line shape of the logarithmic spiral diffusion profile is a straight line, the line shape of the logarithmic spiral profile is a gradually expanding spiral line, the line shape of the volute tongue profile is a curve, and the line shape of the volute tongue diffusion profile is a straight line.

[0007] The volute for the centrifugal fan provided in the embodiment of the present disclosure can achieve the following technical effects: the cross-sectional peripheral profile of the volute enclosure of the present application can well adapt to the viscosity of the flowing gas, and the cross-sectional peripheral profile of the volute enclosure adopts smoothly connected logarithmic spiral diffusion profiles, logarithmic spiral profiles, volute tongue profiles and volute tongue diffusion profiles. Therefore, during the operation of the centrifugal fan, no obvious vortex will appear inside the volute, thereby reducing noise.

[0008] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] One or more embodiments are exemplarily described by corresponding drawings. These exemplary descriptions and drawings do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation. In addition,

[0010] Figure 1 This is a schematic structural diagram of a volute for a centrifugal fan provided by an embodiment of the present disclosure;

[0011] Figure 2 is a cross-sectional schematic diagram of a volute for a centrifugal fan provided by an embodiment of the present disclosure;

[0012] Figure 3 It is a schematic diagram of the outer peripheral profile of the volute enclosure cross section of a volute for a centrifugal fan provided in an embodiment of the present disclosure.

[0013] Reference numerals:

[0014] 1: Logarithmic spiral diffusion profile; 2: Logarithmic spiral profile; 3: Volute tongue profile; 4: Volute tongue diffusion profile; 5: Centrifugal impeller; 10: Air outlet; 11: Volute top plate; 12: Volute enclosure; 13: Volute bottom plate. DETAILED DESCRIPTION

[0015] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The accompanying drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0016] like Figure 1 and Figure 2As shown, according to one aspect of the present invention, a volute for a centrifugal fan is provided, comprising a volute top plate 11, a volute enclosure 12 and a volute bottom plate 13, wherein the volute enclosure 12 is connected between the volute top plate 11 and the volute bottom plate 13, and the cross-sectional outer peripheral profile of the volute enclosure 12 comprises a logarithmic spiral diffusion profile 1, a logarithmic spiral profile 2, a volute tongue profile 3 and a volute tongue diffusion profile 4 which are smoothly connected in a counterclockwise order; wherein the line shape of the logarithmic spiral diffusion profile 1 is a straight line, the line shape of the logarithmic spiral profile 2 is a gradually expanding spiral line, the line shape of the volute tongue profile 3 is a curve, and the line shape of the volute tongue diffusion profile 4 is a straight line.

[0017] The volute top plate 11 and the volute bottom plate 13 are arranged opposite each other, and the volute enclosure 12 is connected along the periphery of the volute top plate 11 and the volute bottom plate 13 to form an air inlet 10. Air inlets are opened at corresponding positions of the volute top plate 11 and the volute bottom plate 13. Preferably, the air inlet is circular in shape to match the shape of the centrifugal impeller 5 and reduce the air inlet pressure loss.

[0018] The volute top plate 11, volute shroud 12, and volute bottom plate 13 can be connected by welding, which is simple and reliable. Alternatively, flanges can be used, with flange edges and through holes reserved at corresponding positions on the volute top plate 11, volute bottom plate 13, and volute shroud 12, and bolted together. This structure is removable, making it easy to clean and repair later.

[0019] like Figure 3 As shown, in some embodiments, the first end a of the logarithmic spiral diffuser profile 1 forms the volute outlet, and the second end b2 is connected to and tangent to the first end b1 of the logarithmic spiral profile 2; the second end c2 of the logarithmic spiral profile 2 is connected to and tangent to the first end c1 of the volute tongue profile 3; the second end d2 of the volute tongue profile 3 is connected to and tangent to the first end d1 of the volute tongue diffuser profile 4; and the second end e of the volute tongue diffuser profile 4 forms the volute outlet. The various portions of the cross-sectional outer peripheral profile of the volute shroud 12 are connected tangentially, achieving a smooth transition, reducing resistance to air flow, and improving centrifugal fan efficiency.

[0020] In some embodiments, the opening angle A of the logarithmic spiral diffuser profile 1 is related to the dynamic viscosity of the gas flowing within the volute, the designed flow rate of the volute, the width of the volute, and the circumferential velocity at the outlet of the centrifugal impeller 5. Specifically, the opening angle A of the logarithmic spiral diffuser profile 1 is the distance between the first end b2 of the logarithmic spiral diffuser profile 1 and the center of the volute cross section minus the radius R of the centrifugal impeller 5. This prevents significant eddy currents from forming within the volute, reducing the operating noise of the centrifugal fan.

[0021] In some embodiments, the greater the dynamic viscosity of the gas flowing within the volute, the larger the opening angle A of the logarithmic spiral diffusion profile 1; the greater the design flow rate of the volute, the larger the opening angle A of the logarithmic spiral diffusion profile 1; the greater the width of the volute, the smaller the opening angle A of the logarithmic spiral diffusion profile 1; and the greater the circumferential velocity at the outlet of the centrifugal impeller 5, the smaller the opening angle A of the logarithmic spiral diffusion profile 1. This prevents significant vortexes from forming within the volute, reducing the operating noise of the centrifugal fan.

[0022] Optionally, the opening angle A of the logarithmic spiral diffusion profile 1 and the dynamic viscosity of the gas flowing in the volute, the design flow rate of the volute, the width of the volute, and the circumferential speed of the outlet of the centrifugal impeller 5 satisfy the following relationship:

[0023] Where α is the correction coefficient; μ is the dynamic viscosity of the gas flowing in the volute; Q n is the design flow of the volute; B is the width of the volute; c 2u is the circumferential velocity of the centrifugal impeller 5 outlet.

[0024] Furthermore, the value range of α is 5.7*10^4-5.9*10^4. In this way, no obvious vortex will appear inside the volute, reducing the operating noise of the centrifugal fan.

[0025] In some embodiments, the first angle θ1 formed between the logarithmic spiral diffusion profile 1 and the set direction (the positive X-axis direction of the volute center coordinate system) is determined based on the opening angle A of the logarithmic spiral diffusion profile 1 and the radius R of the centrifugal impeller 5. In this way, no significant vortex will appear inside the volute, reducing the operating noise of the centrifugal fan.

[0026] In some embodiments, the larger the opening angle A of the logarithmic spiral diffusion profile 1 is, the larger the first angle θ1 is; and the larger the radius R of the centrifugal impeller 5 is, the smaller the first angle θ1 is.

[0027] Optionally, the first angle θ1, the opening angle A of the logarithmic spiral diffusion profile 1, and the radius R of the centrifugal impeller 5 satisfy the following relationship:

[0028]

[0029] Here, λ1 is a correction factor. Furthermore, the value range of λ1 is 1.1-1.3. This prevents significant vortex flow inside the volute, reducing the operating noise of the centrifugal fan.

[0030] In some embodiments, the second angle θ2 formed between the volute tongue diffusion profile 4 and the set direction (the positive X-axis direction of the volute center coordinate system) is determined based on the opening angle A of the logarithmic spiral diffusion profile 1 and the radius R of the centrifugal impeller 5. In this way, no significant vortex will appear inside the volute, reducing centrifugal fan noise.

[0031] In some embodiments, the larger the opening angle A of the logarithmic spiral diffusion profile 1 is, the larger the second angle θ2 is; and the larger the radius R of the centrifugal impeller 5 is, the smaller the second angle θ2 is.

[0032] Optionally, the second angle θ2, the opening angle A of the logarithmic spiral diffusion profile 1, and the radius R of the centrifugal impeller 5 satisfy the following relationship:

[0033]

[0034] Here, λ2 is the correction factor. Furthermore, the value range of λ2 is 0.82-0.92. This prevents significant vortex flow inside the volute, reducing the operating noise of the centrifugal fan.

[0035] The design process of the cross-sectional outer profile of the volute shroud 12 is as follows: establish a plane Cartesian coordinate system, take the coordinate origin as the center, and draw a circle with the radius R of the centrifugal impeller 5 as the radius; determine the design flow rate Q of the volute according to the actual product usage conditions and internal space size. n , the width B of the volute and the circumferential velocity c of the centrifugal impeller 5 outlet 2u , obtain the dynamic viscosity μ of the gas flowing in the volute through experimental testing or data query, and substitute these parameters into the formula In the equation, the opening angle A of the logarithmic spiral diffusion line 1 is obtained, where the value range of α is 5.7*10^4-5.9*10^4; according to the formula Obtain the angle θ1 formed by the logarithmic spiral diffusion line 1 and the positive direction of the X-axis of the volute center coordinate system, where the value range of λ1 is 1.1-1.3; determine the connection point of the logarithmic spiral diffusion line 1 and the logarithmic spiral line 2 and the logarithmic spiral diffusion line 1 according to the angle θ2 formed by the volute tongue diffusion line 4 and the positive direction of the X-axis of the volute center coordinate system and the opening angle A of the logarithmic spiral diffusion line 1; draw the logarithmic spiral line 2 and the volute tongue line 3 in sequence; according to the formula The angle θ2 formed between the volute tongue-divergent profile 4 and the positive X-axis of the coordinate system at the center of the volute is calculated, where λ2 ranges from 0.82 to 0.92. Since the volute tongue-divergent profile 4 is a straight line and tangent to the volute tongue-divergent profile 3, the volute tongue-divergent profile 4 can be determined. At this point, all four parts of the outer peripheral profile of the volute shroud 12 section are determined. These parts are then connected tangentially in sequence to obtain the outer peripheral profile of the volute shroud 12 section.

[0036] According to another aspect of the present invention, a centrifugal fan is provided, comprising the above-mentioned volute and a centrifugal impeller 5 disposed in the volute. Preferably, the axis of the centrifugal impeller 5 coincides with the axis of the low-noise volute.

[0037] According to yet another aspect of the present invention, a range hood is provided, comprising the centrifugal fan described above.

[0038] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure so that those skilled in the art can practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Each embodiment may focus on the differences from other embodiments, and the same similar parts between the various embodiments may refer to each other. When used in this application, although the terms "first", "second", etc. may be used in this application to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without changing the meaning of the description, the first element can be called the second element, and similarly, the second element can be called the first element, as long as all occurrences of the "first element" are renamed consistently and all occurrences of the "second element" are renamed consistently. The first element and the second element are both elements, but may not be the same elements.

Claims

1. A volute for a centrifugal fan, comprising a volute top plate, a volute enclosure and a volute bottom plate, wherein the volute enclosure is connected between the volute top plate and the volute bottom plate, and characterized in that: The outer peripheral profile of the cross section of the volute shroud comprises a logarithmic spiral diffusion profile, a logarithmic spiral profile, a volute tongue profile and a volute tongue diffusion profile that are smoothly connected in counterclockwise order; The line shape of the logarithmic spiral diffusion line is a straight line, the line shape of the logarithmic spiral line is a gradually expanding spiral line, the line shape of the snail tongue line is a curve, and the line shape of the snail tongue diffusion line is a straight line. The opening angle A of the logarithmic spiral diffusion profile, the dynamic viscosity of the gas flowing in the volute, the design flow rate of the volute, the width of the volute, and the circumferential speed of the centrifugal impeller outlet satisfy the following relationship: Where α is the correction coefficient, and the value range of α is 5.7*10^4 to 5.9*10^4; μ is the dynamic viscosity of the gas flowing in the volute; Q n is the design flow of the volute; B is the width of the volute; c 2u is the circumferential velocity of the centrifugal impeller outlet.

2. The volute according to claim 1, wherein: The first end of the logarithmic spiral diffusion line is the outlet of the volute, and the second end is connected to and tangent to the first end of the logarithmic spiral line; The second end of the logarithmic spiral line is connected to and tangent to the first end of the volute tongue line; The second end of the volute tongue profile is connected to and tangent to the first end of the volute tongue diffuser profile; The second end of the volute tongue diffusion profile is the volute outlet.

3. The volute according to claim 1 or 2, characterized in that: The first angle θ1 formed between the logarithmic spiral diffusion profile and the positive direction of the X-axis of the volute center coordinate system is determined according to the opening angle A of the logarithmic spiral diffusion profile and the radius R of the centrifugal impeller.

4. The volute according to claim 3, wherein: The larger the opening angle A of the logarithmic spiral diffusion line is, the larger the first angle θ1 is; The larger the radius R of the centrifugal impeller is, the smaller the first angle θ1 is.

5. The volute according to claim 1 or 2, characterized in that: The second angle θ2 formed by the volute tongue diffusion profile and the positive direction of the X axis of the volute center coordinate system is determined according to the opening angle A of the logarithmic spiral diffusion profile and the radius R of the centrifugal impeller.

6. The volute according to claim 5, wherein: The larger the opening angle A of the logarithmic spiral diffusion line is, the larger the second angle θ2 is; The larger the radius R of the centrifugal impeller is, the smaller the second angle θ2 is.

7. A centrifugal fan for a range hood, characterized in that: The invention comprises the volute according to any one of claims 1 to 6, and a centrifugal impeller arranged in the volute.

8. A range hood, characterized in that: Comprising the centrifugal fan as claimed in claim 7.

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