Centrifugal fan and range hood

Abstract

The utility model belongs to the technical field of range hoods, and particularly relates to a centrifugal fan and a range hood. According to the centrifugal fan disclosed by the utility model, the volute body is integrally formed by injection molding, and the plastic surface has the characteristic of lower roughness, so that the inner wall surface of the volute body is smoother and accords with the hydromechanics characteristics, the generation of airflow friction and turbulent flow is reduced, the gas flow is smoother, and the overall performance of the fan is improved; in addition, the integral injection molding mode is adopted, the volute structure is easier to mold, the volute production design parameters are better met, the relative precision is higher during product molding, and structures such as an involute and a volute tongue are better matched with the theoretical height. And the air extractor is assembled on the inner side of the cover plate and assembled in the volute along with the cover plate, so that the assembly process is simplified, and production and manufacturing are facilitated. Moreover, the cover plate made of metal materials provides stable support for the volute body, the overall structural strength can be effectively improved, and firmer support is provided for installation of the air extractor.

Description

Technical Field

[0001] This utility model belongs to the field of range hood technology and specifically relates to a centrifugal fan and a range hood. Background Technology

[0002] Currently, the manufacturing of the volute casing of centrifugal fans in Chinese-style range hoods mainly relies on two traditional processes: metal butt welding and metal edge riveting. However, both have significant technical defects. Specifically: metal butt welding has low reliability, requiring high-precision welding equipment and skilled operators, and is prone to poor welding and detachment; the finished casing structure has poor sealing, with large gaps in unwelded areas leading to air leakage and oil droplet seepage. Over long-term use, oil accumulation in these gaps directly affects the fan's airflow efficiency; secondary processing defects exist, as welding burrs are difficult to remove completely, easily causing scratches, and localized stress concentration exacerbates vibration and noise. Metal edge riveting has high production costs, requiring large-scale edge riveting equipment, is complex, and has low production efficiency; insufficient dimensional accuracy results in large forming deviations in key parts such as the volute tongue, leading to unstable airflow and potential airflow turbulence and performance degradation over long-term operation; and poor process compatibility makes it difficult to meet the refined design requirements of the volute's spiral involute curve and volute tongue curvature.

[0003] The aforementioned technological defects result in traditional centrifugal fans generally suffering from low aerodynamic efficiency, poor noise control, and short service life. Therefore, there is an urgent need for a fan volute structure that combines high-precision molding, low-friction flow channel design, and ease of assembly. Utility Model Content

[0004] The purpose of this invention is to overcome the problems of low production efficiency and low long-term stability of the volute casing of existing range hood centrifugal fans, and to provide a centrifugal fan and range hood with a volute casing made by injection molding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A centrifugal fan includes a volute housing, a cover plate, and an exhaust fan. The volute housing has an opening on its side and is integrally injection molded. The volute housing is made of plastic, and the cover plate is made of metal. The volute housing has an air inlet collector located in the middle of its front side and an air outlet located at the outer end of the spiral of the volute housing. The cover plate is used to cover the side opening of the volute housing. The exhaust fan is assembled inside the cover plate and is assembled inside the volute housing along with the cover plate. The air inlet collector and the exhaust fan are correspondingly arranged. The exhaust fan includes a motor and an impeller, and the impeller is connected to the output end of the motor.

[0007] Compared with existing technologies, the centrifugal fan of this invention features a volute casing formed by integral injection molding. Due to the lower surface roughness of the plastic, the inner wall of the volute casing is smoother, conforming to fluid mechanics characteristics, reducing airflow friction and turbulence, resulting in smoother gas flow and improved overall fan performance. Furthermore, the integral injection molding method makes the volute casing structure easier to form, better meeting the design parameters for volute casing production, and achieving higher precision during product molding. For example, the involute curve and volute tongue structures are more closely aligned with theoretical heights. The exhaust fan is assembled inside the cover plate and within the volute casing along with the cover plate, simplifying the assembly process, facilitating manufacturing, and minimizing wind power loss when adjusting the airflow direction. Moreover, the metal cover plate provides stable support for the volute casing, effectively improving the overall structural strength and providing more robust support for the exhaust fan installation.

[0008] Furthermore, the cover plate is made of iron; with this arrangement, the metal cover plate provides stable support for the volute housing, which can effectively improve the overall structural strength and provide a more solid support for the installation of the exhaust fan. The plastic volute housing makes full use of the smooth characteristics of plastic to reduce wind resistance.

[0009] Furthermore, the height of the air outlet diffuser is H, the angle between the line connecting the center of the inlet section and the center of the outlet section of the air outlet diffuser and the air outlet direction is E, 0° < E < 45°, and the angle between the center line of the inlet section of the air outlet diffuser 12 and the line connecting one side of the air outlet diffuser 12 is B.

[0010] Furthermore, an air diffuser is provided at the outer end of the spiral of the volute housing, and the air outlet is formed at the outlet of the air diffuser. The inlet cross-section of the air diffuser is polygonal and the outlet cross-section of the air diffuser is circular, or the inlet cross-section of the air diffuser is circular and the outlet cross-section of the air diffuser is polygonal. The line connecting the inlet cross-section and the outlet cross-section of the air diffuser is twisted along the air outlet direction, and the twist angle is 1° to 60°.

[0011] Furthermore, the inner wall of the volute casing is polished, and the outer side of the cover plate is provided with several fixing brackets for mounting and fixing the centrifugal fan; through this arrangement, the polishing of the inner wall of the volute casing can better guide the flow, further reduce the generation of turbulence, and improve the overall performance of the fan.

[0012] Furthermore, the inner wall of the volute housing is provided with a volute tongue arranged in the axial direction at the connection point near the air outlet diffuser. The volute tongue is a short tongue solid structure, and the length of the volute tongue is adapted to the width of the volute housing. This can make the working efficiency curve of the fan using the flue gas volute housing flat, with the advantages of a wide economic working range and low noise. It also effectively reduces some of the gas circulating in the flue gas volute housing, making the inside of the flue gas volute housing smooth and uniform, avoiding large backflow and impact, and reducing airflow noise.

[0013] The width B of the volute is 100mm to 240mm; the opening A of the spiral termination section of the volute is 60mm to 80mm.

[0014] Furthermore, the length of the volute tongue extending into the volute shell is 1 / 20 to 1 / 5, which guides the airflow and reduces airflow resistance.

[0015] Furthermore, the outlet diameter D2 of the impeller is 170mm to 210mm, and the gap t between the outer end of the volute tongue and the outer circumference of the impeller is (0.05 to 0.06) * D2; the gap t between the outer end of the volute tongue and the outer circumference of the impeller is 8.5mm to 12.6mm.

[0016] Furthermore, the outlet size of the volute housing is [80,115]mm*[160,200]mm; the outlet length L of the volute housing is 130mm~170mm; the diffusion angle of the air inlet collector is 30°~50°; and the maximum outer diameter of the volute housing is 200mm~350mm.

[0017] Furthermore, the diffuser has a diffusion angle of 7° to 15° and a height of 55mm to 110mm.

[0018] Furthermore, the cover plate and the opening of the volute housing are positioned and fitted together via a socket structure. This design reduces air leakage in the centrifugal fan, ensures smoother gas flow, and improves the overall performance of the fan.

[0019] Preferably, the coverage area of ​​the socket structure is not less than 2 / 3 of the length of the opening edge of the volute housing 1, ensuring the strength and tightness of the connection, and making assembly more convenient.

[0020] Furthermore, the socket structure includes a positioning protrusion on the outer periphery of the cover plate and a positioning slot on the outer periphery near the opening of the volute housing. When the cover plate is assembled with the volute housing, the positioning protrusion is inserted into the positioning slot. With this configuration, the socket structure is engaged by a snap-fit ​​method, which is simple in structure, convenient for production and processing, and provides a good sealing fit between the cover plate and the opening of the volute housing.

[0021] Furthermore, the edge of the opening side of the volute housing is provided with a plurality of first connecting seats, each with a first connecting hole, and the outer periphery of the cover plate is provided with a second connecting seat, each with a second connecting hole. The first connecting hole and the second connecting hole are fixed together by fasteners. With this arrangement, the assembly connection between the volute housing and the cover plate is achieved by fasteners, and the assembly connection between the volute housing and the cover plate is stable.

[0022] Preferably, the cover plate is detachably connected to the side opening of the volute housing, and the outer wall of the cover plate is provided with a decorative surface, which is an antibacterial coating or an oil-resistant coating, and has durable and stain-resistant properties, meeting the usage requirements of green kitchens.

[0023] Preferably, the outlet of the air diffuser is provided with a support member, the two ends of which are respectively connected to the inner wall of the air diffuser. A limiting block is provided above the connection between the support member and the air diffuser. The limiting block and the support member are used to install and limit the valve.

[0024] The range hood includes a range hood body and a smoke exhaust structure located at the top of the range hood body. The smoke exhaust structure includes a smoke exhaust channel connecting the smoke chamber of the range hood body and a centrifugal fan, with the centrifugal fan located within the smoke exhaust channel. This design allows the volute housing to be integrally injection molded. Due to the lower surface roughness of plastic, the inner wall of the volute housing is smoother, conforming to fluid dynamics characteristics, reducing airflow friction and turbulence, resulting in smoother gas flow and improved overall fan performance. Furthermore, the integral injection molding method makes the volute housing structure easier to form, better meeting the design parameters for volute housing production, and resulting in higher precision during product molding. For example, the involute curve and volute tongue structures are more closely aligned with theoretical heights. The exhaust fan is assembled inside the cover plate and within the volute housing along with the cover plate, simplifying the assembly process and facilitating manufacturing. Attached Figure Description

[0025] Figure 1 Axonometric view of centrifugal fan Figure 1 ;

[0026] Figure 2 Axonometric view of centrifugal fan Figure 2 ;

[0027] Figure 3 This is a diagram of the internal structure of the volute shell;

[0028] Figure 4 This is an exploded view of a centrifugal fan.

[0029] Figure 5 This is a diagram showing the geometric parameters of the volute casing;

[0030] Figure 6This is a diagram showing the geometric parameters of the air outlet diffuser.

[0031] Reference numerals: 1. Volute housing; 11. Inlet air collector; 12. Outlet air diffuser; 121. Outlet; 13. Support component; 14. Limiting block; 15. Positioning slot; 16. First connecting seat; 161. First connecting hole; 17. Volute tongue; 2. Cover plate; 25. Positioning flange; 26. Second connecting seat; 261. Second connecting hole; 3. Exhaust fan; 31. Motor; 32. Impeller; 4. Fixed bracket. Detailed Implementation

[0032] The specific embodiments of this utility model are described below with reference to the accompanying drawings. In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0033] Example 1:

[0034] See Figures 1 to 6 The centrifugal fan of this utility model includes a volute housing 1, a cover plate 2, and an exhaust fan 3. The volute housing 1 has an opening on its side and is integrally injection molded. The volute housing 1 is made of plastic, and the cover plate 2 is made of metal. The volute housing 1 has an air inlet collector 11 located in the middle of the front side and an air outlet located at the outer end of the spiral of the volute housing 1. The cover plate 2 is used to cover the side opening of the volute housing 1. The exhaust fan 3 is assembled inside the cover plate 2 and is assembled inside the volute housing 1 along with the cover plate 2. The air inlet collector 11 and the exhaust fan 3 are arranged correspondingly. The exhaust fan 3 includes a motor 31 and an impeller 32. The impeller 32 is connected to the output end of the motor 31. The distance between the outer edge of the impeller 32 and the inner wall along the air outlet direction of the spiral of the volute housing 1 gradually increases.

[0035] The outer end of the spiral of the volute housing 1 is provided with an air outlet diffuser 12. The air outlet is formed at the outlet of the air outlet diffuser 12. The inlet cross-section of the air outlet diffuser 12 is polygonal and the outlet cross-section of the air outlet diffuser 12 is circular, or the inlet cross-section of the air outlet diffuser is circular and the outlet cross-section of the air outlet diffuser is polygonal.

[0036] See Figure 1 The line connecting the inlet section and the outlet section of the air diffuser 12 is twisted along the air outlet direction, with a twist angle of 1° to 60°. Figure 1The spiral in the figure represents the direction of the torsion angle. More specifically, the torsion angles are 1°, 15°, 30°, 45° and 60° to adapt to different air outlet directions and angles, making the air outlet directionality stronger and reducing air outlet resistance.

[0037] See Figure 6 H is the height of the air outlet diffuser 12. The angle between the line connecting the center of the inlet section and the center of the outlet section of the air outlet diffuser 12 and the air outlet direction is E, where 0° < E < 45°, preferably 20°, 30° and 40°. The angle between the center line of the inlet section of the air outlet diffuser 12 and the line connecting one side of the air outlet diffuser 12 is B, where 30° < B < 75°, preferably 40°, 50°, 60° and 70°.

[0038] Preferably, the opening of the air outlet diffuser 12 is offset toward one side of the centrifugal fan. In conjunction with the torsion of the air outlet diffuser 12, the loss of air volume can be reduced when changing the air outlet angle and air outlet area.

[0039] The volute housing 1 is a spiral volute structure of the centrifugal fan in the existing range hood. The center of the spiral of the volute housing 1 is provided with an air inlet. The air inlet collector 11 is formed in the air inlet. The outer end of the spiral of the volute housing 1 is provided with a rectangular air outlet 121. The air outlet diffuser 12 is installed at the air outlet 121. The outer end of the air outlet diffuser 12 is a circular opening and its inner end is a rectangular opening. The inner end of the air outlet diffuser 12 is installed at the air outlet 121 by fasteners.

[0040] Compared with existing technologies, the centrifugal fan of this invention features a volute housing 1 formed by integral injection molding. Due to the lower surface roughness of the plastic, the inner wall of the volute housing 1 is smoother, conforming to fluid dynamics characteristics, reducing airflow friction and turbulence, resulting in smoother gas flow and improved overall fan performance. Furthermore, the integral injection molding method makes the volute structure easier to form, better meeting the design parameters for volute production, and achieving higher precision during product molding. For example, the involute curve and volute tongue 17 structures are more closely aligned with theoretical heights. The exhaust fan 3 is assembled inside the cover plate 2 and within the volute housing 1 along with the cover plate 2, simplifying the assembly process and facilitating manufacturing. Moreover, the metal cover plate 2 provides stable support for the volute housing 1, effectively improving the overall structural strength and providing a more robust support for the installation of the exhaust fan 3.

[0041] See Figures 1 to 4 In one embodiment, the cover plate 2 is made of iron. With this arrangement, the metal cover plate 2 provides stable support for the volute housing 1, effectively improving the structural strength of the cover plate 2 and providing a more solid support for the installation of the exhaust fan 3. The plastic volute housing makes full use of the low molding depth and smooth surface of the plastic inner wall, reducing the resistance to airflow.

[0042] See Figures 1 to 4 In one embodiment, the exhaust fan 3 uses centrifugal airflow, which improves the exhaust effect of oil fumes.

[0043] See Figures 1 to 4 In one embodiment, the inner wall of the volute 1 is polished, and the outer side of the cover plate 2 is provided with several fixing brackets 4 for mounting and fixing the centrifugal fan. With this arrangement, the polishing of the inner wall of the volute can better guide the flow, further reduce the generation of turbulence, and improve the overall performance of the fan.

[0044] See Figures 1 to 4 In one embodiment, the cover plate 2 has a positioning protrusion 25 on its outer periphery, and the volute housing 1 has a positioning slot 15 on its outer periphery on the opening side. When the cover plate 2 and the volute housing 1 are assembled, the positioning protrusion 25 is inserted into the positioning slot 15. The edge of the volute housing 1 on the opening side is provided with a plurality of first connecting seats 16, each with a first connecting hole 161. The cover plate 2 has a second connecting seat 26 on its outer periphery, each with a second connecting hole 261. The first connecting hole 161 and the second connecting hole 261 are fixed together by fasteners, such as bolts, studs, screws, nuts, self-tapping screws, wood screws, washers, retaining rings, pins, rivets, assemblies and connecting pairs, and welding studs. With this arrangement, the cover plate 2 and the volute housing 1 are positioned and assembled by the positioning slot 15 and the positioning protrusion 25, and then further fixed by screws, making the assembly method convenient.

[0045] See Figures 1 to 5 In one embodiment, a volute tongue 17 is provided at the connection between the inner wall of the volute housing 1 and the air outlet diffuser 12, arranged in the axial direction. The volute tongue 17 extends inward perpendicular to the air outlet direction. The length of the volute tongue 17 is adapted to the width of the volute housing 1. The volute tongue 17 is a short tongue solid structure, which can make the working efficiency curve of the fan using the volute housing flat and the air outlet noise low. It can also effectively reduce the circulation of some gas in the volute housing, making the airflow inside the volute housing smoother and more uniform, avoiding backflow and airflow impact, and reducing airflow noise.

[0046] Based on the size of the gap between the volute and the impeller and its structural characteristics, the volute tongue in the fan casing is mainly divided into four types: pointed tongue, deep tongue, short tongue, and flat tongue. The above four types of volute tongue are mentioned in "Shang Jingtai, Practical Technical Handbook for Ventilation Fans, Machinery Industry Press (Second Edition), 2005". The content about the shape of the short tongue structure is disclosed on page 133 of the above-mentioned practical technical handbook.

[0047] Furthermore, the ratio of the volute tongue length to the volute housing width is in the range of 1 / 20 to 1 / 5. More specifically, the ratio of the volute tongue 17 length to the width of the volute housing 1 in the air outlet direction is 1 / 20, 1 / 10, and 1 / 5. The length of the volute tongue 17 is adapted to the width of the volute housing 1. The length of the volute tongue 17 extending into the volute housing is a low proportion of the width of the volute housing, which can make the working efficiency curve of the fan using this smoke hood volute housing flat and reduce the noise of the air outlet.

[0048] See Figures 1 to 5 In one embodiment, the volute width B is 100mm to 240mm, and preferably 150mm, 186mm or 230mm; the opening A of the spiral termination section of the volute 1 is 60mm to 80mm, and preferably 65mm, 75mm or 80mm.

[0049] See Figures 1 to 5 In one embodiment, the outlet width C of the air diffuser 12 is 1.4*A = 105mm to 133mm, and the outlet width C is preferably 110mm, 116mm or 130mm.

[0050] See Figures 1 to 5 In one embodiment, the volute tongue angle of the volute housing 1 is 40° to 60°, preferably 40°, 50° or 60°, and the angle between the volute tongue 17 and the air outlet direction is the volute tongue angle, which is used for air outlet guidance.

[0051] See Figures 1 to 5 In one embodiment, the outlet diameter D2 of the impeller 32 is 170mm to 210mm, and the gap t between the outer end of the volute tongue 17 and the outer circumference of the impeller 32 is (0.05 to 0.06) * D2; the gap t between the outer end of the volute tongue 17 and the outer circumference of the impeller 32 is 8.5mm to 12.6mm. Preferably, the gap t is 9mm, 10mm, 11mm, 12mm or 12.4mm.

[0052] See Figures 1 to 5 In one embodiment, the outlet size of the volute housing 1 is [80,115]mm*[160,200]mm, and the outlet size of the volute housing of the smoke hood is preferably 90mm*176mm, 100mm*186mm or 110mm*200mm; the outlet length L of the volute housing 1 is 130mm to 170mm, preferably 140mm, 150mm, 160mm or 170mm; the diffusion angle of the air inlet collector 11 is 30° to 50°, preferably 35°, 40°, 45° or 49°; the maximum outer diameter of the volute housing is 200mm to 350mm, preferably 250mm or 342mm.

[0053] See Figures 1 to 5In one embodiment, the diffuser 12 has a diffusion angle of 7° to 15°, preferably 7°, 10°, 12° or 15°, and a diffuser height of 55mm to 110mm, preferably 60mm, 70mm, 76mm, 80mm, 90mm or 100mm.

[0054] Example 2:

[0055] See Figures 1 to 5 This invention relates to a centrifugal fan, comprising a volute housing 1, a cover plate 2, and an exhaust fan 3. The volute housing 1 has a side opening and is integrally injection molded. The cover plate 2 covers the side opening of the volute housing 1. The exhaust fan 3 is assembled inside the cover plate 2 and is also assembled inside the volute housing 1 along with the cover plate 2. The cover plate 2 and the opening of the volute housing 1 are positioned and fitted together by a socket structure. This design, with the volute housing 1 integrally injection molded, results in a smoother inner wall surface due to the lower surface roughness of the plastic, conforming to fluid dynamics characteristics, reducing airflow friction and turbulence, and improving gas flow, thus enhancing the overall performance of the fan. Furthermore, the integral injection molding method makes the volute structure easier to form, better conforming to the volute housing production design parameters, and resulting in higher relative precision during product molding. For example, the involute curve and volute tongue structures are more closely aligned with theoretical heights. The exhaust fan 3, assembled inside the cover plate 2 and also within the volute housing 1, simplifies the assembly process and facilitates manufacturing.

[0056] Furthermore, the coverage area of ​​the socket structure is no less than 2 / 3 of the length of the opening edge of the volute housing 1, that is, the contact length of the positioning protrusion 25 and the positioning slot 15 accounts for the proportion of the total opening edge, which ensures the strength and tightness of the connection and makes assembly more convenient.

[0057] In addition, the cover plate 2 and the opening of the volute housing 1 are positioned and fitted by a socket structure, which better reduces the air leakage problem of the centrifugal fan, makes the gas flow smoother, and improves the overall performance of the fan.

[0058] See Figures 2 to 5 In one embodiment, the socket structure includes a positioning protrusion 25 disposed on the outer periphery of the cover plate 2 and a positioning slot 15 disposed on the outer periphery near the opening of the volute housing 1. When the cover plate 2 and the volute housing 1 are assembled, the positioning protrusion 25 is inserted into the positioning slot 15. With this arrangement, the socket structure is simple in structure and easy to manufacture, and the sealing fit between the cover plate 2 and the opening of the volute housing 1 is good.

[0059] See Figures 2 to 5In one embodiment, the edge of the opening side of the volute housing 1 is provided with a plurality of first connecting seats 16, each first connecting seat 16 having a first connecting hole 161. The outer periphery of the cover plate 2 is provided with a second connecting seat 26, each second connecting seat 26 having a second connecting hole 261. The first connecting hole 161 and the second connecting hole 261 are fixed together by fasteners. With this arrangement, the assembly connection between the volute housing 1 and the cover plate 2 is achieved by using fasteners, and the assembly connection between the volute housing 1 and the cover plate 2 is stable.

[0060] See Figures 1 to 5 The inlet cross-section of the air outlet diffuser 12 is polygonal, and the outlet cross-section of the air outlet diffuser 12 is circular.

[0061] Furthermore, the cover plate 2 is detachably connected to the side opening of the volute housing 1. The outer wall of the cover plate 2 is provided with a decorative surface, which is the same as the appearance style of the external equipment, making it easy to match different environments. It can also provide a certain degree of anti-fouling and antibacterial ability, improving the cleanliness of the kitchen interior. Its application range is wider and its aesthetics are better.

[0062] Preferably, the decorative surface is a pattern patch or an antibacterial coating, which meets the requirements for health and aesthetics during use.

[0063] Furthermore, a support member 13 is provided on the outlet of the air diffuser 12. The two ends of the support member 13 are respectively connected to the inner wall of the air diffuser 12, and the support member 13 is located in the middle of the exhaust port of the air diffuser. This is to prevent the air diffuser 12 from deforming during long-term use and affecting the air outlet efficiency, while also improving the strength of the connection to external equipment.

[0064] Preferably, a limiting block 14 is provided above the connection between the support member 13 and the air diffuser 12. The limiting block 14 is fixed on the inner wall of the air diffuser 12. The limiting block 14 and the support member 13 are used for installing and positioning the valve.

[0065] The centrifugal fan of this utility model, the centrifugal fan of Embodiment 1 and the centrifugal fan of Embodiment 2 can be used and shared by each other, or the structures of the two can be combined.

[0066] Example 3:

[0067] See Figures 1 to 5The main purpose of this embodiment is to provide a range hood (not shown) using a centrifugal fan from Embodiment 1 or Embodiment 2, including a range hood body and a smoke exhaust structure located on the top of the range hood body. The smoke exhaust structure includes a smoke exhaust channel connecting the smoke chamber of the range hood body and a centrifugal fan, with the centrifugal fan located within the smoke exhaust channel. With this configuration, the volute housing 1 of the centrifugal fan is integrally injection molded, which can well meet the design size requirements of the volute tongue 17, better guide the airflow, reduce the generation of turbulence, and improve the overall performance of the fan. In addition, the exhaust fan 3 is assembled inside the cover plate 2 and is assembled inside the volute housing 1 along with the cover plate 2, which simplifies the assembly process and facilitates manufacturing.

[0068] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A centrifugal fan, characterized in that, The device includes a volute housing, a cover plate, and an exhaust fan. The volute housing has an opening on its side and is integrally injection molded. The volute housing is made of plastic, and the cover plate is made of metal. The volute housing has an air inlet collector located in the middle of its front side and an air outlet located at the outer end of the spiral of the volute housing. The cover plate is used to cover the side opening of the volute housing. The exhaust fan is assembled inside the cover plate and is assembled inside the volute housing along with the cover plate. The air inlet collector and the exhaust fan are arranged correspondingly. The exhaust fan includes a motor and an impeller, and the impeller is connected to the output end of the motor.

2. The centrifugal fan according to claim 1, characterized in that, The inner wall of the volute casing is polished, and the outer side of the cover plate is provided with several fixing brackets for mounting and fixing the centrifugal fan.

3. The centrifugal fan according to claim 1, characterized in that, The outer end of the spiral of the volute is provided with an air outlet diffuser. The height of the air outlet diffuser is H. The angle between the line connecting the center of the inlet section of the air outlet diffuser and the center of the outlet section of the air outlet diffuser and the air outlet direction is E, 0° < E < 45°. The angle between the center line of the inlet section of the air outlet diffuser and the line connecting one side of the air outlet diffuser is B. An air outlet diffuser is provided at the outer end of the spiral of the volute housing. The air outlet is formed at the outlet of the air outlet diffuser. The inlet cross-section of the air outlet diffuser is polygonal and the outlet cross-section of the air outlet diffuser is circular, or the inlet cross-section of the air outlet diffuser is circular and the outlet cross-section of the air outlet diffuser is polygonal. The line connecting the inlet and outlet sections of the air diffuser is twisted along the air outlet direction, with a twist angle of 1° to 60°.

4. The centrifugal fan according to claim 3, characterized in that, The inner wall of the volute housing is provided with a volute tongue arranged in the axial direction at the connection point near the air outlet diffuser. The volute tongue is a short tongue solid structure, and the length of the volute tongue is adapted to the width of the volute housing. The width B of the volute is 100mm to 240mm; The opening A of the spiral termination section of the volute is 60 mm to 80 mm.

5. The centrifugal fan according to claim 4, characterized in that, The length of the volute tongue extending into the volute shell is 1 / 20 to 1 / 5.

6. The centrifugal fan according to claim 4, characterized in that, The outlet diameter D2 of the impeller is 170mm to 210mm, and the gap t between the outer end of the volute tongue and the outer circumference of the impeller is (0.05 to 0.06) * D2. Furthermore, the gap t between the outer end of the volute tongue and the outer circumference of the impeller is 8.5mm to 12.6mm.

7. The centrifugal fan according to claim 1, characterized in that, The outlet size of the volute housing is [80,115]mm*[160,200]mm; the outlet length L of the volute housing is 130mm~170mm; the diffusion angle of the air inlet collector is 30°~50°; and the maximum outer diameter of the volute housing is 200mm~350mm.

8. The centrifugal fan according to claim 3, characterized in that, The diffuser has a diffusion angle of 7° to 15° and a height of 55mm to 110mm.

9. The centrifugal fan according to claim 1, characterized in that, The cover plate and the opening of the volute housing are positioned and fitted together by a socket structure.

10. The centrifugal fan according to claim 9, characterized in that, The coverage area of ​​the socket structure is not less than 2 / 3 of the length of the opening edge of the volute.

11. The centrifugal fan according to claim 9, characterized in that, The socket structure includes a positioning protrusion on the outer periphery of the cover plate and a positioning slot on the outer periphery near the opening of the volute housing. When the cover plate is assembled with the volute housing, the positioning protrusion is inserted into the positioning slot.

12. The centrifugal fan according to claim 8, characterized in that, The edge of the opening side of the volute is provided with a plurality of first connecting seats, each with a first connecting hole. The outer periphery of the cover plate is provided with a second connecting seat, each with a second connecting hole. The first connecting hole and the second connecting hole are fixed together by fasteners.

13. The centrifugal fan according to claim 1, characterized in that, The cover plate is detachably connected to the side opening of the volute housing, and the outer wall of the cover plate is provided with a decorative surface, which is an antibacterial coating or an oil-resistant coating.

14. The centrifugal fan according to claim 3, characterized in that, The outlet of the air diffuser is provided with a support member, and the two ends of the support member are respectively connected to the inner wall of the air diffuser. A limiting block is provided above the connection between the support member and the air diffuser. The limiting block and the support member are used to install and limit the valve.

15. A range hood, characterized in that, The device includes a range hood body and a smoke exhaust structure located on top of the range hood body. The smoke exhaust structure includes a smoke exhaust channel communicating with the smoke chamber of the range hood body and a centrifugal fan as described in any one of claims 1 to 14. The centrifugal fan is located within the smoke exhaust channel.

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