Air duct assembly and lampblack treatment equipment

Abstract

The invention discloses an air duct assembly and lampblack treatment equipment, and belongs to the technical field of kitchen appliances. The air duct assembly comprises a machine case, a centrifugal fan arranged in the machine case, a partition plate, two independent flow channels and two pre-rotation flow guide pieces, the partition plate is arranged in the machine case and divides the machine case into a first cavity and a second cavity which are arranged up and down and are not communicated with each other, the centrifugal fan is located in the first cavity, and two through holes are formed in the partition plate at intervals; one flow channel is communicated with one air inlet and one through hole of a volute of the centrifugal fan, and the other flow channel is communicated with the other air inlet and the other through hole of the volute; the two pre-whirling flow guide pieces are arranged in the two flow channels correspondingly, and the pre-whirling flow guide pieces can enable oil smoke in the flow channels to obtain a rotation angle and then enter the centrifugal fan. Due to the synergistic effect of the double-flow-channel design and the pre-swirling flow guide part, energy loss caused by airflow separation and vortex falling is remarkably reduced; the rising oil smoke obtains a certain rotation angle through the pre-rotation flow guide piece and enters the centrifugal fan, and the oil smoke can be discharged easily.

Description

Technical Field

[0001] This invention relates to the field of kitchen appliance technology, and in particular to a duct assembly and a fume treatment device. Background Technology

[0002] Cooking fumes directly impact the living environment and user health. Fume treatment equipment is a kitchen appliance designed to purify the kitchen environment. Its main function is to absorb and exhaust these fumes during cooking, thereby purifying indoor air and maintaining a healthy kitchen environment. Existing fume treatment equipment includes a duct assembly and a smoke collection chamber, with the chamber located below and connected to the duct assembly. The duct assembly consists of a main unit and a fan housed within it. During operation, the fan creates a negative pressure zone above the stove, drawing indoor fumes into the duct assembly through the smoke collection chamber. The fumes are then exhausted outdoors through ductwork.

[0003] Traditional fume treatment equipment typically uses a single-cavity structure for its main unit, where airflow separation easily occurs under the action of a centrifugal fan, resulting in significant energy loss. Fume treatment equipment often uses volute fans to draw in, collect, and exhaust fumes outdoors. A volute fan consists of a volute casing and an impeller housed within it. Air inlets are formed on opposite sides of the volute casing, and these inlets are coaxially aligned with the impeller.

[0004] Existing volute fans typically include a front cover, a rear cover, and surrounding plates. However, the surrounding plates are usually rectangular with equal width, while the front and rear covers are typically flat. This planar structure results in poor airflow guidance, leading to resistance and energy loss during airflow transmission, thus affecting intake efficiency and increasing fan noise. Because the distances on both sides of the volute are equal, the large flow rate is mismatched with the volute's shape, easily causing increased airflow separation within the volute and generating separation noise. Furthermore, insufficient diffusion within the volute prevents the airflow from converting kinetic energy into potential energy, thus reducing fan performance. Traditional volute fans often use simple guide cones or straight cylinders for their inlets, which can cause abrupt impacts when the airflow enters the impeller, increasing turbulence losses, significantly increasing boundary layer separation, and generating high-frequency aerodynamic noise. In addition, the direct connection between the smoke collection chamber and the main unit leads to uneven airflow distribution, further exacerbating energy loss.

[0005] Therefore, there is an urgent need to design a duct component and fume treatment equipment to solve the above-mentioned technical problems. Summary of the Invention

[0006] One object of the present invention is to provide a duct assembly that reduces energy loss and improves the efficiency of fume extraction and fume exhaust.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] A duct assembly includes a chassis and a centrifugal fan disposed inside the chassis, the duct assembly further comprising:

[0009] A partition is provided inside the chassis and divides the chassis into a first cavity and a second cavity that are arranged vertically and are not connected to each other. The centrifugal fan is located in the first cavity. The partition is provided with two through holes at intervals.

[0010] Two independent flow channels, one flow channel connecting an air inlet and a through hole of the centrifugal fan casing, and the other flow channel connecting another air inlet and another through hole of the centrifugal fan casing; and,

[0011] Two pre-swirl guides are respectively installed in the two flow channels. The pre-swirl guides enable the oil fumes in the flow channels to gain a rotation angle before entering the centrifugal fan.

[0012] As an optional technical solution for the above-mentioned air duct assembly, the air duct is formed by a guide pipe. The two ends of one guide pipe are respectively connected to an air inlet and a through hole of the centrifugal fan casing, and the two ends of the other guide pipe are respectively connected to another air inlet and another through hole of the casing.

[0013] As an optional technical solution for the above-mentioned air duct assembly, the guide pipe includes a bent section and a straight section. One end of the bent section is connected to the air inlet of the volute, and the other end is connected to the straight section. The end of the straight section away from the bent section is connected to the through hole, and the pre-swirl guide is disposed in the straight section.

[0014] As an optional technical solution for the above-mentioned air duct assembly, the two air ducts are symmetrically arranged about the centrifugal fan.

[0015] As an optional technical solution for the above-mentioned air duct assembly, the flow distribution between the two flow channels satisfies the formula: ≈1, where Q is the flow rate of the channel, A is the cross-sectional area of ​​the channel, f is the coefficient of friction, and L is the length of the central axis of the channel.

[0016] As an optional technical solution for the aforementioned air duct assembly, the pre-spin guide is a NACA airfoil blade, with the number of blades n ranging from 2 to 6, the chord length c ranging from 15mm to 35mm, and the pre-spin angular momentum satisfying the formula: v θ The circumferential velocity component of the airflow downstream of the pre-swirl guide is given, and the ratio of the circumferential velocity component to the axial velocity component of the airflow downstream of the pre-swirl guide satisfies the formula: =0.3-0.4, where β is the installation angle and r is the blade installation radius.

[0017] As an optional technical solution for the above-mentioned air duct assembly, the total height x1 of the pre-swirl guide member satisfies 0.5D < x1 < 1.5D, and the distance x2 between the highest point of the pre-swirl guide member and the lowest point of the bend section pipe opening satisfies 0 < x2 < D, where D is the diameter of the guide pipe.

[0018] As an optional technical solution for the above-mentioned air duct assembly, the air duct assembly further includes:

[0019] A flow guide plate is disposed below the partition and between the two through holes.

[0020] As an optional technical solution for the above-mentioned air duct assembly, the guide plate includes a first plate and a second plate connected in a V-shape, and the included angle α between the first plate and the second plate satisfies α=50°±5°.

[0021] Another objective of this invention is to provide an oil fume treatment device with low energy consumption and high oil fume extraction efficiency.

[0022] To achieve this objective, the present invention adopts the following technical solution:

[0023] An oil fume treatment device includes a smoke collection chamber and the aforementioned air duct assembly, wherein the smoke collection chamber is disposed below the air duct assembly and is connected to the air duct assembly.

[0024] The duct assembly disclosed in this invention includes a chassis, a centrifugal fan disposed inside the chassis, a partition, two independent flow channels, and two pre-swirl guides. The partition is disposed inside the chassis and divides the chassis into a first cavity and a second cavity that are arranged vertically and are not interconnected. The centrifugal fan is located in the first cavity. Two through holes are provided at intervals on the partition. One flow channel connects an air inlet and a through hole of the centrifugal fan's volute, and the other flow channel connects another air inlet and another through hole of the volute. The two pre-swirl guides are respectively disposed in the two flow channels. The pre-swirl guides enable the oil fumes in the flow channels to gain a rotation angle before entering the centrifugal fan.

[0025] By setting up two independent flow channels connecting the second chamber and the two air inlets of the centrifugal fan respectively, the fumes can be directly guided from the fume collection chamber to the centrifugal fan, avoiding the accumulation and impact of fumes in the first chamber and reducing the energy loss of the fume treatment equipment. The dual-flow channel design allows the fumes to enter the centrifugal fan in two separate paths, improving the flow balance and reducing pressure loss. By setting pre-swirling guides in the two independent flow channels, the synergistic effect of the dual-flow channel design and the pre-swirling guides is achieved, significantly reducing the energy loss caused by airflow separation and vortex shedding. At the same time, the rising fumes can also gain a certain rotation angle after flowing through the pre-swirling guides before entering the centrifugal fan, which is more conducive to the exhaust of fumes, thereby improving the fume extraction efficiency and the fume exhaust efficiency.

[0026] The oil fume treatment device disclosed in this invention includes a smoke collection chamber and the aforementioned air duct assembly. The smoke collection chamber is located below the air duct assembly and is connected to the air duct assembly. This oil fume treatment device has low energy consumption and high oil fume extraction and exhaust efficiency. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the fume treatment equipment provided in a specific embodiment of the present invention;

[0029] Figure 2 This is an exploded view of a portion of the structure of the fume treatment equipment provided in a specific embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of a portion of the oil fume treatment equipment provided in a specific embodiment of the present invention;

[0031] Figure 4 This is a partial structural schematic diagram of the air duct assembly provided in a specific embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the pre-swirl guide and the guide tube provided in a specific embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of the guide plate provided in a specific embodiment of the present invention.

[0034] In the picture:

[0035] 100. Air duct assembly; 200. Smoke collection chamber;

[0036] 1. Chassis; 2. Centrifugal fan; 3. Partition plate; 4. Pre-swirl guide; 5. Guide pipe; 6. Guide plate; 51. Bend section; 52. Straight pipe section. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0043] This embodiment discloses an oil fume treatment device, which can be any type of device with oil fume treatment function, such as a top-mounted range hood, a side-suction range hood, or a top-suction range hood. All types of devices with oil fume treatment function are within the protection scope of this embodiment. This embodiment takes a top-mounted range hood as an example to describe the structure of the oil fume treatment device.

[0044] like Figure 1 As shown, the fume treatment equipment includes a duct assembly 100 and a smoke collection chamber 200. The smoke collection chamber 200 is located below and connected to the duct assembly 100. Figures 2 to 4 As shown, the air duct assembly 100 includes a housing 1 and a centrifugal fan 2 installed inside the housing 1. When in use, the centrifugal fan 2 operates, creating a negative pressure zone in a certain space above the stove, drawing indoor fumes into the air duct assembly 100 through the smoke collection chamber 200, and then discharging the fumes outdoors through the pipe.

[0045] Centrifugal fan 2 includes a volute casing and an impeller disposed within the volute casing. Air inlets are formed on opposite sides of the volute casing, and the air inlets on both sides are coaxially arranged with the impeller. For example... Figure 2 and Figure 3As shown, the duct assembly 100 of this embodiment further includes a partition 3, two independent flow channels, and two pre-swirl guides 4. The partition 3 is disposed within the housing 1, dividing the housing 1 into a first chamber and a second chamber that are vertically arranged and not interconnected. The centrifugal fan 2 is located in the first chamber. Two through holes are spaced apart on the partition 3. Both independent flow channels are disposed in the first chamber. One flow channel connects to one air inlet and one through hole of the centrifugal fan 2's volute, and the other flow channel connects to another air inlet and another through hole of the volute, thus forming two independent flue gas flow channels on both sides of the centrifugal fan 2. The two pre-swirl guides 4 are respectively disposed in the two flow channels, allowing the fumes in the flow channels to gain a rotational angle before entering the centrifugal fan 2.

[0046] In the above structure, the chassis 1 is divided into two independent spaces by the partition 3. The two air inlets and the second chamber of the centrifugal fan 2 are connected by two independent flow channels. Compared with the direct connection between the smoke collection chamber 200 and the chassis 1 in the prior art, the oil fumes can be directly guided from the smoke collection chamber 200 to the centrifugal fan 2, avoiding the accumulation and impact of oil fumes in the first chamber and reducing the energy loss of the oil fume treatment equipment. The dual-flow channel design allows the oil fumes to enter the centrifugal fan 2 in two separate paths, improving the flow balance and reducing pressure loss. By setting pre-swirl guides 4 in the two independent flow channels, the synergistic effect of the dual-flow channel design and the pre-swirl guides 4 is achieved, significantly reducing the energy loss caused by airflow separation and vortex shedding. At the same time, the rising oil fumes can also obtain a certain rotation angle after flowing through the pre-swirl guides 4 before entering the centrifugal fan 2, which is more conducive to the exhaust of oil fumes, thereby improving the oil fume absorption efficiency and oil fume exhaust efficiency.

[0047] Optionally, the partition 3 is sealed to the inner wall of the chassis 1 to divide the chassis 1 into a first cavity and a second cavity that are not interconnected. Specifically, this can be achieved by connecting them with screws.

[0048] In this embodiment, the flow channel is formed by guide pipes 5. One guide pipe 5 has its two ends connected to an air inlet and a through hole of the centrifugal fan 2's volute, respectively. The other guide pipe 5 has its two ends connected to another air inlet and another through hole of the volute, respectively. The fumes entering the smoke collection chamber 200 directly enter the centrifugal fan 2 through the two guide pipes 5, reducing energy loss. Using a pipe structure to form the flow channel is simple and easy to implement. In other feasible embodiments, the flow channel is not limited to guide pipes 5; it can also be a flow channel opened inside a plate-shaped structure.

[0049] like Figure 2 and Figure 5As shown, the guide pipe 5 includes a bent section 51 and a straight section 52. One end of the bent section 51 is connected to the air inlet of the volute, and the other end is connected to the straight section 52. The end of the straight section 52 away from the bent section 51 is connected to a through hole. A pre-swirl guide 4 is installed in the straight section 52. Under the action of the centrifugal fan 2, the rising fumes are guided directly into the centrifugal fan 2 by the bent section 51, reducing the energy loss of the fume treatment equipment. Since the airflow forms a shedding vortex structure in the bent section 51, a pre-swirl guide 4 is installed in the straight section 52 below the bent section 51. This allows the rising fumes to obtain a certain airflow angle in the pre-swirl guide 4, reducing energy loss in the bent section 51 and also allowing the fumes to obtain a certain rotation angle before entering the centrifugal fan 2, which is more conducive to the exhaust of fumes and improves the extraction and exhaust efficiency of the fume treatment equipment.

[0050] Optionally, the guide pipe 5 is a one-piece molded part, that is, the bend section 51 and the straight section 52 are a one-piece molded structure, which makes the sealing between the bend section 51 and the straight section 52 better and the processing is more convenient.

[0051] In the above structure, the two flow channels are symmetrically arranged about the centrifugal fan 2. The symmetry of the two flow channels structurally makes the airflow into the centrifugal fan 2 more balanced, thereby reducing noise.

[0052] The flow distribution between the two channels satisfies the formula: Where Q is the flow rate of the flow channel, A is the cross-sectional area of ​​the flow channel, f is the coefficient of friction, and L is the length of the central axis of the flow channel. Through structural design, such as designing the cross-sectional area and central axis length of the two flow channels and selecting a suitable coefficient of friction, Q1≈Q2 is achieved, i.e., the above formula Q1 / Q2≈1. The uniform flow distribution of the two flow channels ensures balanced airflow into the centrifugal fan 2, reducing pressure loss and noise.

[0053] The pre-spin guide 4 is a NACA airfoil blade, with the number of blades n ranging from 2 to 6, and the chord length c ranging from 15 mm to 35 mm. The pre-spin angular momentum satisfies the formula: That is, constant, v θ The circumferential velocity component of the airflow downstream of the pre-swirl guide 4 is given. The ratio of the circumferential velocity component to the axial velocity of the airflow downstream of the pre-swirl guide 4 satisfies the formula: =0.3-0.4, where β is the installation angle and r is the blade installation radius. This structural design reduces impeller inlet impact loss. Specifically, the pre-swirl guide 4 is a NACA 6512 airfoil blade.

[0054] like Figure 5As shown, the total height x1 of the pre-swirling guide 4 satisfies 0.5D < x1 < 1.5D, and the distance x2 between the highest point of the pre-swirling guide 4 and the lowest point of the pipe opening of the bend section 51 satisfies 0 < x2 < D, where D is the diameter of the guide pipe 5.

[0055] In this embodiment, the air duct assembly 100 further includes a guide plate 6, which is disposed below the partition 3 and located between the two through holes. The guide plate 6, situated in the second cavity and between the two through holes, can guide the flue gas to the two through holes respectively, that is, guide the flue gas to the two flow channels respectively. Preferably, the guide plate 6 is positioned in the middle of the two through holes to better balance the airflow distribution.

[0056] like Figure 6 As shown, the guide plate 6 is a V-shaped plate, comprising a first plate and a second plate connected in a V-shape. The included angle α between the first plate and the second plate satisfies α = 50° ± 5°. The V-shaped guide plate 6 enables a more uniform distribution of the flue gas velocity in the smoke collection chamber 200, thus allowing the flue gas to enter the two flow channels evenly. This angle setting ensures the guiding effect of the guide plate 6 on the flue gas, guiding all the flue gas into the two flow channels, thereby ensuring the efficiency of oil fume extraction. It should be noted that the included angle α between the first plate and the second plate can be adjusted according to the distance between the two through holes on the partition 3, as long as all the oil fumes are guided into the flow channels.

[0057] Under the action of centrifugal fan 2, the rising fumes pass through V-shaped guide plate 6, which guides the fumes into two guide pipes 5. The fumes are then guided directly into centrifugal fan 2 by the bend section 51. Compared with the direct connection design between the fume collection chamber 200 and the casing 1, this reduces the energy loss of the fume treatment equipment. Since the airflow forms a shedding vortex structure in the bend section 51, a pre-swirl guide 4 is installed inside the straight pipe section 52 below the bend section 51. The pre-swirl guide 4 allows the rising fumes to obtain a certain airflow angle, reducing energy loss in the bend section 51 while allowing the fumes to obtain a certain rotation angle upon entering the centrifugal fan 2, which is more conducive to the exhaust of fumes and thus improves the fume exhaust efficiency.

[0058] In this embodiment, the duct assembly 100 adopts a composite flow guiding structure to optimize airflow organization. It combines the V-shaped flow guide plate 6 with the pre-swirling flow guide 4 to solve the energy loss problem caused by airflow separation and vortex shedding in traditional range hoods. At the same time, the pre-swirling airflow improves the inlet flow state of the centrifugal fan 2 and enhances the smoke exhaust efficiency.

[0059] Obviously, the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

[0060] Note that in the description of this specification, the references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A duct assembly comprising a housing (1) and a centrifugal fan (2) disposed inside the housing (1), characterized in that, The air duct assembly also includes: A partition (3) is provided inside the chassis (1) and divides the chassis (1) into a first cavity and a second cavity that are arranged vertically and not connected to each other. The centrifugal fan (2) is located in the first cavity. The partition (3) is provided with two through holes at intervals. Two independent flow channels, one of which connects to an air inlet and a through hole of the volute casing of the centrifugal fan (2), and the other flow channel connects to another air inlet and another through hole of the volute casing; and, Two pre-swirl guides (4) are respectively installed in the two flow channels. The pre-swirl guides (4) enable the oil fumes in the flow channels to gain a rotation angle before entering the centrifugal fan (2).

2. The air duct assembly according to claim 1, characterized in that, The flow channel is formed by a guide pipe (5). The two ends of one guide pipe (5) are respectively connected to an air inlet and a through hole of the volute of the centrifugal fan (2), and the two ends of the other guide pipe (5) are respectively connected to another air inlet and another through hole of the volute.

3. The air duct assembly according to claim 2, characterized in that, The guide pipe (5) includes a bent section (51) and a straight section (52). One end of the bent section (51) is connected to the air inlet of the volute, and the other end is connected to the straight section (52). The end of the straight section (52) away from the bent section (51) is connected to the through hole. The pre-rotating guide (4) is disposed in the straight section (52).

4. The air duct assembly according to any one of claims 1-3, characterized in that, The two flow channels are symmetrically arranged about the centrifugal fan (2).

5. The air duct assembly according to claim 4, characterized in that, The flow distribution between the two channels satisfies the formula: ≈1, where Q is the flow rate of the channel, A is the cross-sectional area of ​​the channel, f is the coefficient of friction, and L is the length of the central axis of the channel.

6. The air duct assembly according to claim 5, characterized in that, The pre-spin guide (4) is a NACA airfoil blade, with the number of blades n ranging from 2 to 6, the chord length c ranging from 15 mm to 35 mm, and the pre-spin angular momentum satisfying the formula: v θ The circumferential velocity component of the downstream airflow of the pre-swirl guide (4) is given, and the ratio of the circumferential velocity component to the axial velocity of the downstream airflow of the pre-swirl guide (4) satisfies the formula: =0.3-0.4, where β is the installation angle and r is the blade installation radius.

7. The air duct assembly according to claim 3, characterized in that, The total height x1 of the pre-swirling guide (4) satisfies 0.5D < x1 < 1.5D, and the distance x2 between the highest point of the pre-swirling guide (4) and the lowest point of the pipe opening of the bend section (51) satisfies 0 < x2 < D, where D is the diameter of the guide pipe (5).

8. The air duct assembly according to claim 1, characterized in that, The air duct assembly also includes: A flow guide plate (6) is disposed below the partition plate (3) and located between the two through holes.

9. The air duct assembly according to claim 8, characterized in that, The guide plate (6) includes a first plate and a second plate connected in a V-shape, and the included angle α between the first plate and the second plate satisfies α=50°±5°.

10. An oil fume treatment device, comprising a fume collection chamber (200), characterized in that, The fume treatment equipment further includes a duct assembly (100) as described in any one of claims 1-9, wherein the fume collection chamber (200) is disposed below the duct assembly (100) and communicates with the duct assembly (100).

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