A fan and a range hood

Abstract

This utility model relates to a fan, including a volute and an impeller disposed within the volute. A flow guiding device is provided at the air inlet of the impeller, and the flow guiding device includes at least one flow guiding element. The flow guiding element includes a base, a first plate located outside the impeller, and a second plate located inside the impeller. The base is tubular and forms a central flow channel extending along the impeller axial direction. The circumferential edge of the base, away from the outer end of the impeller, extends radially outward to cover the air inlet to form the first plate. The circumferential edge of the inner end of the base extends radially outward to form the second plate. The radial length of the first plate is greater than the radial length of the second plate. This fan can improve the uniformity of airflow velocity distribution reaching the blades in the impeller and reduce turbulent noise. This utility model also relates to a range hood, including the aforementioned fan.

Description

Technical Field

[0001] This utility model relates to a fan, and also to a range hood that uses the fan. Background Technology

[0002] Range hoods have become an indispensable kitchen appliance in modern homes. They operate on the principles of fluid dynamics, using a centrifugal fan installed inside to draw in and exhaust cooking fumes. The centrifugal fan consists of a casing, an impeller housed within the casing, and a motor that drives the impeller. As the impeller rotates, a negative pressure is generated at the center of the fan, drawing in the cooking fumes from below. After being accelerated by the fan, the fumes are collected by the casing and guided outwards.

[0003] To reduce the risk of users bumping their heads and to improve the aesthetics of a slim design, existing range hoods are beginning to use slim fans. For example, Chinese invention patent CN113310085B (application number 202110586605.3) and Chinese utility model patent CN215863629U (application number 202122053725.5) both disclose range hoods that use slim fans.

[0004] Due to their reduced thickness, thin-type fans have relatively narrow inlet spaces. The presence of the inlet panel increases turbulence, and the close distance between the inlet and the panel partially obstructs the inlet collector, weakening the overall guiding effect of the inlet ring and increasing vortices in the impeller area. Especially at low flow rates, uneven impeller load and flow rate cause instability in the impeller flow to develop and increase at the boundary, resulting in more dead zones. Furthermore, the airflow entering the fan changes direction before reaching the blades. The air no longer flows in a straight line but undergoes a more pronounced axial-to-radial curvature before reaching the blades, exhibiting a greater degree of curvature than in relatively thick centrifugal fans. At the rear of the impeller, centrifugal force causes the velocity to increase, leading to a difference in airflow velocity between the front and rear sides of the impeller. This difference in airflow velocity makes the velocity distribution of the air reaching the blades uneven, thus exacerbating turbulent noise.

[0005] Furthermore, in fans, there is a gap between the impeller and the inner surface of the volute. In ultra-thin fans, where space is limited, some air forced into the volute's flow channel flows back through this gap into the radially inner region of the impeller blades, creating backflow. This backflow interferes with the airflow drawn in at the inlet, thus generating noise. Even if the impeller's front plate extends into the impeller, it cannot effectively prevent backflow. Utility Model Content

[0006] The first technical problem to be solved by this utility model is to provide a fan that can improve the uniformity of airflow velocity distribution to the blades in the impeller and reduce turbulence noise, in contrast to the above-mentioned prior art.

[0007] The second technical problem to be solved by this utility model is to provide a fan that can effectively suppress backflow and secondary diversion and reduce noise, in contrast to the above-mentioned prior art.

[0008] The third technical problem to be solved by this utility model is to provide a range hood that uses the aforementioned fan, in contrast to the prior art.

[0009] The technical solution adopted by this utility model to solve the first technical problem mentioned above is: a fan, including a volute and an impeller disposed in the volute, wherein a flow guiding device is provided at the air inlet of the impeller, and the flow guiding device includes at least one flow guiding element;

[0010] The flow guide includes a base, a first plate located outside the impeller, and a second plate located inside the impeller;

[0011] The substrate is tubular and has a central flow channel extending along the impeller axis. The circumferential edge of the substrate away from the outer end of the impeller extends radially outward to cover the air inlet to form the first plate. The circumferential edge of the inner end of the substrate extends radially outward to form the second plate. The radial length of the first plate is greater than the radial length of the second plate.

[0012] Preferably, the substrate, the first plate, and the second plate are integrally connected.

[0013] Preferably, the axial cross-section of the sidewall of the substrate is an arc-shaped curve that bends radially inward.

[0014] To improve the uniformity of the airflow entering the fan, the guide element includes at least two nested elements, with the same gap between each pair of adjacent guide elements.

[0015] Preferably, the impeller includes a front disc disposed on the air inlet side of the volute, a rear disc disposed behind the front disc, and a plurality of blades connecting the front disc and the rear disc, wherein the front disc is annular to form the air inlet.

[0016] The technical solution adopted by this utility model to solve the second technical problem mentioned above is as follows: the cross-section of the front disc is arc-shaped and curved radially outward from front to back along the air inlet direction; the front end of the blades on the impeller has a curved surface in the radial inward direction from the connection point with the front disc, opposite to the curvature direction of the front disc cross-section; the inner wall of the volute is formed with a trumpet-shaped groove along the circumferential direction for the front edge of the front disc to be inserted. The groove and the front disc form a labyrinth structure in cross-section, blocking most of the backflow airflow, effectively suppressing the airflow entering the volute from flowing back into the impeller through the gap between the groove and the front disc, thereby reducing backflow interference noise.

[0017] In order to effectively prevent the backflow of air in the volute from flowing smoothly back into the impeller through the gap between the volute and the front disc and interfering with the airflow entering the impeller from the outside, and thus avoid noise, a barrier side plate extends in the opposite direction of the air intake around the rear edge of the front disc, and a side plate body is provided circumferentially around the outer periphery of the barrier side plate on the inner wall of the volute.

[0018] In order to effectively diffuse the backflow and secondary flow in the airflow entering the volute through the impeller during the formation stage and reduce the noise associated with backflow, secondary flow and impeller interference, a first backflow suppression plate is provided circumferentially on the inner wall of the front side plate of the volute. The first backflow suppression plate is located radially outside the impeller.

[0019] As an improvement, a second backflow suppression plate is provided circumferentially on the inner wall of the rear side plate of the volute, and the second backflow suppression plate is disposed relative to the first suppression plate.

[0020] The technical solution adopted by this utility model to solve the third technical problem mentioned above is: a range hood, including the aforementioned fan.

[0021] Compared with existing technologies, the advantages of this invention are as follows: The fan in this invention can effectively guide the airflow direction entering the impeller through the flow guiding device, that is, guide the newly entering airflow to flow radially along the impeller, and thus merge well with the radially flowing airflow in the volute. The direction of the newly entering airflow in the merging flow is consistent with the airflow direction inside the volute. In other words, the flow guiding device suppresses the problem in existing technologies where airflow enters the fan axially and bends due to centrifugal force, resulting in a large difference in airflow velocity between the front and rear sides of the impeller. Based on the guiding effect of the flow guiding device, the increase in airflow velocity caused by airflow merging inside the volute is suppressed, thereby making the airflow velocity distribution reaching the blades in the impeller more uniform and suppressing the generation of turbulent noise.

[0022] Range hoods using this fan facilitate the design of slim fans. While using slim fans, they can also effectively suppress turbulent noise caused by uneven airflow, thus improving the user experience. Attached Figure Description

[0023] Figure 1This is a perspective view of the fan in an embodiment of this utility model.

[0024] Figure 2 This is a cross-sectional view of the fan in an embodiment of this utility model. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] like Figure 1 and Figure 2 As shown, the fan in this embodiment includes a volute 1 and an impeller 2 disposed within the volute 1. The impeller 2 includes a front disc 21 disposed on the air inlet side of the volute 1, a rear disc 22 disposed behind the front disc 21, and a plurality of blades 23 connecting the front disc 21 and the rear disc 22. The front disc 21 is annular and forms an air inlet. For ease of understanding, in this embodiment, the air inlet side of the fan is defined as the front side, and the side of the fan away from the air inlet side is referred to as the rear side.

[0027] A flow guide device 3 is provided at the air inlet of the impeller 2. Part of the flow guide device 3 is located inside the impeller 2, guiding the external airflow into the impeller 2. Based on the centrifugal force generated when the impeller 2 rotates, the airflow enters the volute 1 and is finally discharged through the air outlet of the volute 1. In the prior art, the airflow enters the impeller 2 axially. Under the centrifugal force of the impeller 2, the airflow direction will turn before entering the volute 1. Furthermore, based on the axial direction of the airflow, the airflow will move towards the rear of the impeller 2 and accumulate there. This is particularly pronounced in thin fans with small thicknesses, leading to uneven airflow velocity on the front and rear sides of the impeller 2, causing turbulent noise. The flow guide device 3 in this embodiment guides the direction of the airflow entering the impeller 2. Specifically, in this embodiment, the flow guiding device 3 guides the airflow to flow into the impeller 2 in a radially outward direction, so that the airflow flows directly into the volute 1, avoiding the situation where the airflow gathers at the rear of the impeller 2 due to centrifugal force, thereby improving the uniformity of the airflow velocity in the impeller 2 and greatly reducing turbulence noise.

[0028] The flow guiding device 3 in this embodiment includes at least one flow guiding element 30. The number of flow guiding elements 30 is specifically set according to needs, such as the volume of the fan, the thickness of the fan, and the air volume handling capacity. The flow guiding element 30 includes a base 301, a first plate 302 located outside the impeller 2, and a second plate 303 located inside the impeller 2. The base 301 is tubular and forms a central flow channel extending along the axial direction of the impeller 2. The central flow channel is relatively small, which can satisfy the communication between the airflow outside the fan and the airflow inside the fan, while minimizing the airflow flow from the central flow channel into the impeller 2. The circumferential edge of the base 301 away from the outer end of the impeller 2 extends radially outward to cover the air inlet to form the first plate 302. The circumferential edge of the inner end of the base 301 extends radially outward to form the second plate 303. The radial length of the first plate 302 is greater than the radial length of the second plate 303. The first plate 302 and the second plate 303, connected by the base 301, provide a 180° rotating flow channel for the airflow outside the fan. This allows the airflow to flow radially inward and then turn 180° before entering the impeller 2 radially outward. This ensures that the new airflow entering the impeller 2 flows in the same direction as the airflow inside the fan driven by the rotation of the impeller 2, guaranteeing uniformity of the airflow velocity at all positions in the axial direction and effectively avoiding turbulent noise. Furthermore, the design of the first plate 302 covering the air inlet prevents airflow from entering the impeller 2 through gaps, or minimizes axial entry into the impeller 2, reducing airflow velocity differences and minimizing turbulent noise.

[0029] In order to allow the airflow to enter the impeller 2 smoothly, the base 301, the first plate 302, and the second plate 303 are integrally connected, and the axial section of the side wall of the base 301 is a radially inward curved arc, so that the small amount of airflow flowing into the impeller 2 through the central flow channel can also have a certain component in the radial direction, thereby improving the uniformity of the airflow velocity entering the impeller 2 as much as possible.

[0030] When the guide element 30 includes at least two, the guide elements 30 are stacked together, and the gap between each two adjacent guide elements 30 is the same, so as to separate the airflow outside the fan into multiple uniform airflows and introduce them into the impeller 2.

[0031] The fan in this invention effectively guides the airflow direction entering the impeller 2 through the flow guiding device 3. Specifically, it guides the newly entering airflow to flow radially along the impeller 2, thus merging it well with the radially flowing airflow in the volute 1. The newly entering airflow in the merged flow is aligned with the airflow direction inside the volute 1. In other words, the flow guiding device 3 suppresses the problem in existing technologies where airflow enters the fan axially and bends due to centrifugal force, resulting in a large difference in airflow velocity between the front and rear sides of the impeller 2. Based on the guiding effect of the flow guiding device 3, the increase in airflow velocity caused by airflow merging inside the volute 1 is suppressed, leading to a more uniform airflow velocity distribution reaching the blades 23 in the impeller 2, and suppressing the generation of turbulent noise.

[0032] The airflow entering the volute 1 through the impeller 2 inevitably experiences backflow, especially since there is usually a gap between the front disc 21 of the impeller 2 and the volute 1, where the backflow is more pronounced. To avoid this backflow interfering with the noise generated by the new airflow entering the volute 1, in this embodiment, the front disc 21 has an arc-shaped cross-section that curves radially outward from front to back along the airflow direction. The front end of the blade 23 on the impeller 2 has a curved surface 231 that is opposite to the curvature direction of the front disc 21's cross-section, starting from the connection point with the front disc 21. That is, from the connection point between the front end of the blade 23 and the front disc 21, the curve of the curved surface 231 is mirror-symmetrical to the cross-sectional curve of the front disc 21. The inner wall of the volute 1 is circumferentially formed with a trumpet-shaped groove 11 for the front edge of the front disc 21 to be inserted. The groove 11 can be formed by a recess inside the volute 1 or by a corresponding plate inside the volute 1. Thus, the groove 11 and the front plate 21 form a labyrinthine channel structure in cross-section, blocking most of the backflow airflow and effectively suppressing the airflow entering the volute 1 from flowing back into the impeller 2 through the gap between the groove 11 and the front plate 21, thereby reducing backflow interference noise. Even if a small amount of airflow flows back from the volute 1 into the gap between the front plate 21 and the inner wall of the volute 1, it is contracted and straightened as it passes through the curved path gap between the front plate 21 and the groove 11, thus reducing the disturbance in the airflow. The airflow is released to the leading edge of the blade 23 in a state where the disturbance has been reduced, and the curved surface 231 of the leading edge of the blade 23 also reduces noise.

[0033] To further and effectively prevent the backflow of air inside the volute 1 from smoothly flowing back into the impeller 2 through the gap between the volute 1 and the front plate 21, thus interfering with the airflow entering the impeller 2 from the outside and thereby avoiding noise, this embodiment further increases the complexity of the labyrinth channel and the number of curved sections in the labyrinth channel's curved path. Specifically, a barrier side plate 211 extends in the opposite direction of the air inlet direction around the rear edge of the front plate 21, and a side plate body 12 is circumferentially arranged on the inner wall of the volute 1 around the outer periphery of the barrier side plate 211. The structure formed by the front plate 21 and the barrier side plate 211, together with the channel 11 and the side plate body 12, forms a labyrinth path with two consecutive curved sections, further enhancing the blocking effect on backflow and further reducing the interference of backflow on the newly introduced airflow inside the fan, thereby further enhancing the noise reduction effect.

[0034] To effectively diffuse the backflow and secondary flow in the airflow entering the volute 1 from the impeller 2 during the formation stage, and to reduce the noise associated with the backflow and secondary flow interfering with the impeller 2, a first backflow suppression plate 13 is circumferentially arranged on the inner wall of the front side plate of the volute 1, located radially outward of the impeller 2. A second backflow suppression plate 14 is circumferentially arranged on the inner wall of the rear side plate of the volute 1, positioned relative to the first suppression plate. The axial length of the first backflow suppression plate 13 and the second backflow suppression plate 14 is in ratio to the axial length of the impeller 2 between 1 / 6 and 1 / 4. The first backflow suppression plate 13 and the second backflow suppression plate 14 block the backflow and secondary flow in the airflow within the volute 1 from flowing into the impeller 2 from the front and rear ends, respectively, reducing backflow without reducing the efficiency of the fan, thereby achieving the purpose of reducing noise.

[0035] This utility model also relates to a range hood, including the aforementioned fan. Range hoods using this fan facilitate the design of slim fans, and while using a slim fan, they can also effectively suppress turbulent noise caused by uneven airflow, thus improving the user experience.

[0036] In the specification and claims of this utility model, terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," are used to describe various exemplary structural parts and elements of the invention. However, the use of these terms is merely for illustrative purposes and is based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A fan, comprising a volute (1) and an impeller (2) disposed within the volute (1), characterized in that: The impeller (2) is provided with a flow guiding device (3) at the air inlet, and the flow guiding device (3) includes at least one flow guiding element (30); The flow guide (30) includes a base (301), a first plate (302) located outside the impeller (2), and a second plate (303) located inside the impeller (2); The substrate (301) is tubular and has a central flow channel extending along the axial direction of the impeller (2). The circumferential edge of the substrate (301) away from the outer end of the impeller (2) extends radially outward to cover the air inlet to form the first plate (302). The circumferential edge of the inner end of the substrate (301) extends radially outward to form the second plate (303). The radial length of the first plate (302) is greater than the radial length of the second plate (303).

2. The fan according to claim 1, characterized in that: The substrate (301), the first plate (302), and the second plate (303) are integrally connected.

3. The fan according to claim 1, characterized in that: The axial cross-section of the sidewall of the substrate (301) is an arc-shaped curve that bends radially inward.

4. The fan according to any one of claims 1 to 3, characterized in that: The flow guide (30) includes at least two and is stacked, with the same gap between each pair of adjacent flow guides (30).

5. The fan according to any one of claims 1 to 3, characterized in that: The impeller (2) includes a front disc (21) disposed on the air inlet side of the volute (1), a rear disc (22) disposed on the rear side of the front disc (21), and a plurality of blades (23) connected between the front disc (21) and the rear disc (22). The front disc (21) is annular and forms the air inlet.

6. The fan according to claim 5, characterized in that: The front disc (21) has an arc-shaped cross section and is radially outward from front to back along the air intake direction; the front end of the blade (23) on the impeller (2) has a curved surface (231) that is opposite to the bending direction of the front disc (21) in the radial inward direction from the connection with the front disc (21). The inner wall of the volute (1) is circumferentially formed with a trumpet-shaped groove (11) into which the front edge of the front disc (21) is inserted.

7. The fan according to claim 6, characterized in that: The rear edge of the front disc (21) extends in the opposite direction of the air intake direction with a barrier side plate (211), and the inner wall of the volute (1) is provided with a side plate body (12) in the circumferential direction on the outer periphery of the barrier side plate (211).

8. The fan according to any one of claims 1 to 3, characterized in that: A first backflow suppression plate (13) is provided circumferentially on the inner wall of the front side plate of the volute (1), and the first backflow suppression plate (13) is located radially outside the impeller (2).

9. The fan according to claim 8, characterized in that: A second backflow suppression plate (14) is provided circumferentially on the inner wall of the rear side plate of the volute (1), and the second backflow suppression plate (14) is disposed relative to the first suppression plate.

10. A range hood, characterized in that: Includes the wind turbine as described in any one of claims 1 to 9.

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