Pipeline fan and range hood device comprising same

Abstract

The utility model discloses a pipeline fan and a range hood device comprising the pipeline fan, the pipeline fan is arranged in a horizontal extension mode so that oil smoke can circulate in the horizontal direction, the pipeline fan comprises a main body section, an inlet switching section and an outlet switching section, and the inlet switching section and the outlet switching section are arranged at the two ends of the main body section in the flowing direction of the oil smoke. The inlet switching section is connected with a smoke pipe of the range hood, and the height of the bottom end, allowing oil to flow in the radial direction, of the outlet switching section is not larger than the height of the bottom end of the joint of the outlet switching section and the main body section. The outlet switching section adopts the structural form, so that the pipeline fan is in a left-high and right-low form, oil can be smoothly discharged, the problem that an air duct of the pipeline fan is blocked due to excessive accumulated oil is avoided, and the service life of the pipeline fan is prolonged. According to the technical scheme, through the reasonable design of the height of the outlet switching section, the double effects of smooth circulation of oil smoke and accumulated oil discharge are achieved, and therefore the working efficiency and stability of the pipeline fan are improved.

Description

Technical Field

[0001] The utility model relates to the field of stoves, in particular to a pipeline fan and a range hood device comprising the same. Background Art

[0002] In the prior art, in order to improve the oil fume suction effect of the range hood, an axial flow or mixed flow duct fan is often connected in series to the rear end of the range hood in the market to increase the working air volume of the range hood and thus achieve the effect of increasing the oil fume suction amount. However, in order to increase the working air volume of the range hood, the duct fan needs to have sufficient air performance, so its outer diameter is usually large, which makes it have a large difference in diameter with the smoke pipe in the range hood. Therefore, a transition section connected to the smoke pipe is set on the duct fan to enhance its suction efficiency, but there is a problem: when the duct fan provides suction power to the range hood to absorb the oil fume, part of the oil will also be sucked into the duct fan, and due to the structural form of the duct fan in the prior art, it will cause the problem of the oil accumulation in the duct fan being unable to be discharged in the long run, and finally cause the flow channel to be blocked, affecting the suction effect.

[0003] Therefore, the problem that the oil accumulated in the pipeline fan in the prior art is difficult to be discharged needs to be solved urgently. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the defect in the prior art that the oil accumulated in the duct fan is not easy to be discharged, and to provide a duct fan and a range hood device including the duct fan.

[0005] The utility model solves the above technical problems through the following technical solutions:

[0006] A duct fan, which is horizontally extended to allow oil smoke to circulate in a horizontal direction. The duct fan includes a main body section and an inlet transition section and an outlet transition section arranged at both ends of the main body section along the flow direction of the oil smoke, wherein the inlet transition section is connected to the smoke pipe of the range hood, and the bottom end height of the outlet transition section along its radial direction for oil liquid circulation is not higher than the bottom end height of the connection between it and the main body section.

[0007] In the present technical solution, the outlet adapter section adopts the above-mentioned structural form so that the duct fan forms a shape that is higher on the left and lower on the right, which can enable the oil to be discharged smoothly, avoid the problem of excessive oil accumulation causing blockage of the duct of the duct fan, and extend the service life of the duct fan. In addition, the oil accumulation problem is solved, and the frequency of maintenance and cleaning of the duct fan is reduced, thereby extending the maintenance cycle and reducing maintenance costs. In summary, the technical solution achieves the dual effects of smooth circulation of oil smoke and discharge of accumulated oil through the reasonable design of the height of the outlet adapter section, thereby improving the working efficiency and stability of the duct fan.

[0008] Preferably, along the flow direction of the oil smoke, the bottom end of the outlet adapter section for the oil liquid to flow is extended in the horizontal direction;

[0009] Alternatively, the height of the bottom end of the outlet transition section for oil flow gradually decreases along the radial direction thereof.

[0010] In this technical solution, the bottom end of the outlet adapter section is extended in the horizontal direction to ensure that the bottom end of the outlet adapter section and the bottom end of the main section are maintained at the same horizontal position, so that the oil will not encounter height differences when flowing in the pipeline fan, which is conducive to the smooth discharge of the oil; the bottom end height of the outlet adapter section is gradually lowered, so that the oil has a natural inclined route, which is more conducive to the smooth flow and discharge of the oil from the pipeline fan, and prevents the accumulation of oil from causing blockage. In general, whether the bottom end is extended in the horizontal direction or the bottom end height is gradually lowered, it is to optimize the flow and drainage of oil smoke in the pipeline fan, thereby improving the smoke extraction efficiency and stability of the pipeline fan.

[0011] Preferably, the bottom end of the outlet transition section for oil flow and the bottom end of the main section are at the same level, the inner diameter of the connection between the outlet transition section and the main section is the same as the inner diameter of the main section and its inner diameter gradually decreases along the flow direction of the oil smoke.

[0012] In this technical solution, the bottom end of the outlet adapter section is at the same level as the bottom end of the main section, ensuring that the flow of oil in the pipeline fan will not be affected by the height difference, which is conducive to the smooth discharge of oil. The inner diameter of the connection between the outlet adapter section and the main section is the same as the inner diameter of the main section, and the inner diameter gradually decreases along the flow direction of the oil fume. This design helps to accelerate the flow rate of oil fume in the pipeline fan, thereby enhancing the effect of oil discharge, and in the process of gradually decreasing the inner diameter, it can also more effectively bring the oil into the oil discharge port, reducing the possibility of liquid accumulation.

[0013] Preferably, the inlet transition section and / or the outlet transition section are threadedly connected to the main body section.

[0014] In this technical solution, the threaded connection can not only ensure that the connection between the inlet adapter section and the outlet adapter section and the main section is tighter, thereby effectively preventing air and oil fume leakage, but also avoid oil leakage and other problems, thereby improving the sealing of the duct fan. In addition, the threaded connection provides a more secure connection method, which can resist the vibration and pressure generated during the operation of the duct fan, reduce the possibility of loose connection parts, and improve the stability and reliability of the duct fan. In addition, the threaded connection is easier to install and disassemble than other connection methods (such as flange connection), which makes the maintenance and cleaning of the duct fan more convenient and quick, saving maintenance costs and time.

[0015] Preferably, a first tooth structure is provided on the inner wall surface at the connection between the inlet transition section and / or the outlet transition section and the main body section, and a second tooth structure is provided on the outer wall surface of the main body section corresponding to the first tooth structure, so as to realize the movable connection between the inlet transition section and / or the outlet transition section and the main body section.

[0016] In the technical solution, the design of the first tooth structure and the second tooth structure enables the inlet adapter section and / or the outlet adapter section to be movably connected to the main section, which not only ensures the stability of the connection, prevents the connection part from loosening or falling off, and ensures the safe and stable operation of the duct fan, but also can provide a sealing effect between the inlet adapter section and / or the outlet adapter section and the main section to avoid air leakage, oil leakage, etc. In addition, it can also allow the duct fan to adjust the angle or position within a certain range, increasing the flexibility of the duct fan to meet the requirements of the installation environment or the needs of actual operation.

[0017] Preferably, a stopper is provided on the outer wall surface of the main body section, and the stopper is located on a side of the second toothed structure away from the inlet transition section and / or the outlet transition section;

[0018] The extending direction of the limiting member is perpendicular to the axial direction of the main body section.

[0019] In the present technical solution, by setting the limiter, the overlapping range of the inlet transition section and / or the outlet transition section on the main section can be effectively limited. This position limitation can ensure that the inlet transition section and / or the outlet transition section are connected to the correct position of the main section to ensure the normal operation of the duct fan.

[0020] Preferably, a stop piece is provided on the second toothed structure at one end of the main body section near the outlet transition section, and the stop piece is arranged along the axial extension direction of the main body section, and the height of the stop piece along the radial direction of the main body section is lower than the height of the central axis of the main body section.

[0021] In the technical solution, the setting of the stopper limits the moving range of the outlet adapter section on the main section, thereby ensuring that the outlet adapter section is in the correct position. Specifically, along the radial direction of the outlet adapter section, the center axis height of the outlet adapter section is ensured to be lower than the center axis height of the main section, and the outlet adapter section is ensured to be eccentric relative to the main section, so as to ensure that the bottom end height of the outlet adapter section for oil flow is not higher than the height of the connection between it and the main section, thereby ensuring the smooth discharge of the oil.

[0022] Preferably, the main body section has a uniform inner diameter along the flow direction of the oil smoke;

[0023] And / or, the inner diameter of the inlet transition section gradually increases along the flow direction of the oil smoke, and the inner diameter of the connection between the inlet transition section and the main body section is the same as the inner diameter of the main body section.

[0024] In this technical solution, the inner diameter of the main section is equal along the flow direction of the oil fume, so that the flow of the oil fume in the pipeline will not be hindered or suddenly changed, thereby ensuring the smooth flow of the oil fume. The gradually increasing inner diameter of the inlet transition section can reduce the resistance of the oil fume before entering the pipeline fan, further improving the circulation efficiency of the oil fume, and the inner diameter of the connection between the inlet transition section and the main section is the same as the inner diameter of the main section, which not only avoids the pressure accumulation caused by the sudden change of the inner diameter, but also ensures that the oil fume will not produce excessive pressure changes during the flow process in the pipeline, which is conducive to the stable operation of the pipeline fan, but also helps to avoid looseness or oil leakage at the connection, and improves the overall reliability of the pipeline fan.

[0025] Preferably, the duct fan further comprises a fan assembly, and the fan assembly is arranged in the main body section;

[0026] The fan assembly comprises an impeller, and a central axis of the impeller is the same as a central axis of the main body section.

[0027] In this technical solution, the fan assembly is arranged inside the main body section, and the internal space of the duct fan is utilized, so that the structure of the entire duct fan is more compact, and the space utilization efficiency is optimized to the maximum extent. In addition, the central axis of the impeller is the same as the central axis of the main body section, ensuring that the impeller is aligned with the axis of the pipeline during operation, which not only reduces the vibration and noise caused by offset or imbalance, but also makes the operation of the impeller more stable, reduces energy loss, and improves the stability of the operation of the fan assembly.

[0028] A range hood device comprises a range hood and any one of the above-mentioned duct fans, wherein the duct fan is arranged at the rear end of the range hood along the oil fume flow direction and is connected to the smoke duct of the range hood through the inlet adapter section.

[0029] In this technical solution, the duct fan is arranged at the tail end of the range hood along the oil fume flow direction, which can increase additional wind suction after the oil fume passes through the range hood, improve the efficiency of oil fume suction, effectively enhance the oil suction capacity of the range hood, and improve the oil fume purification effect. In addition, the duct fan is connected to the smoke pipe of the range hood through the inlet adapter section, ensuring an effective connection between the two, avoiding air leakage or oil leakage, ensuring close cooperation between the range hood and the duct fan, and making the entire range hood device run more stably.

[0030] The positive and progressive effects of the utility model are:

[0031] 1. The duct fan, by adopting the above-mentioned structural form for the outlet adapter section so that the duct fan forms a shape with the left side higher and the right side lower, can make the oil discharge smoothly, avoid the problem of excessive oil accumulation leading to blockage of the duct of the duct fan, and extend the service life of the duct fan. In addition, the oil accumulation problem is solved, and the frequency of maintenance and cleaning of the duct fan can be reduced, thereby extending the maintenance cycle and reducing maintenance costs. In summary, this technical solution achieves the dual effects of smooth circulation of oil smoke and discharge of accumulated oil through the reasonable design of the height of the outlet adapter section, thereby improving the working efficiency and stability of the duct fan.

[0032] 2. The oil fume extraction device, by arranging the duct fan at the tail end of the oil fume extraction machine along the oil fume flow direction, can increase additional wind suction force after the oil fume passes through the oil fume extraction machine, thereby improving the oil fume extraction efficiency, effectively enhancing the oil absorption capacity of the oil fume extraction machine, and improving the oil fume purification effect. In addition, the duct fan is connected to the smoke pipe of the oil fume extraction machine through the inlet adapter section, ensuring an effective connection between the two, avoiding air leakage or oil leakage, ensuring close cooperation between the oil fume extraction machine and the duct fan, and making the entire oil fume extraction machine device run more stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the external structure of a duct fan according to a preferred embodiment of the utility model.

[0034] Figure 2 This is a schematic diagram of the internal structure of a duct fan according to a preferred embodiment of the utility model.

[0035] Figure 3 for Figure 2 Enlarged view of part A in .

[0036] Figure 4 It is a structural schematic diagram of the main body section of a preferred embodiment of the utility model.

[0037] Figure 5 for Figure 4 Enlarged view of part B in .

[0038] Description of reference numerals:

[0039] Duct fan 100

[0040] Main body 11

[0041] The first tooth structure 111

[0042] Limiting piece 112

[0043] Stop piece 113

[0044] Import transfer section 12

[0045] Export transfer section 13

[0046] The first tooth structure 14

[0047] Fan assembly 15

[0048] Impeller 151

[0049] Oil smoke flow direction X DETAILED DESCRIPTION

[0050] The present invention is further described below by way of embodiments, but the present invention is not limited to the scope of the embodiments.

[0051] like Figure 1-Figure 5 As shown, this embodiment discloses a duct fan 100, which is arranged at the rear end of the range hood and is used to provide power for the range hood to enhance the oil fume extraction efficiency of the range hood.

[0052] The duct fan 100 is horizontally extended so that the oil smoke flows in the horizontal direction. The duct fan 100 includes a main body section 11 and an inlet adapter section 12 and an outlet adapter section 13 arranged at both ends of the main body section 11 along the oil smoke flow direction X. The inlet adapter section 12 is connected to the smoke pipe of the range hood, and the bottom height of the outlet adapter section 13 along its radial direction for oil liquid flow is not higher than the bottom height of the connection between it and the main body section 11.

[0053] In this embodiment, the outlet adapter section 13 adopts the above-mentioned structural form so that the duct fan 100 forms a shape with the left side higher and the right side lower, which can enable the oil to be discharged smoothly, avoid the problem of excessive oil accumulation leading to blockage of the air duct of the duct fan 100, and extend the service life of the duct fan 100. In addition, the oil accumulation problem is solved, and the frequency of maintenance and cleaning of the duct fan 100 can be reduced, thereby extending the maintenance cycle and reducing maintenance costs. In summary, this technical solution achieves the dual effects of smooth circulation of oil smoke and discharge of accumulated oil through the reasonable design of the height of the outlet adapter section 13, thereby improving the working efficiency and stability of the duct fan 100.

[0054] like Figure 1-Figure 2As shown, the main body section 11 has the same inner diameter along the flow direction X of the oil fume, so that the flow of the oil fume in the pipeline will not be hindered or suddenly changed, thereby ensuring the smooth flow of the oil fume. The gradually increasing inner diameter of the inlet adapter section 12 can reduce the resistance of the oil fume before entering the pipeline fan 100, further improving the circulation efficiency of the oil fume, and the inner diameter of the connection between the inlet adapter section 12 and the main body section 11 is the same as the inner diameter of the main body section 11, which not only avoids the pressure accumulation caused by the sudden change of the inner diameter, but also ensures that the oil fume will not produce excessive pressure changes during the flow process in the pipeline, which is conducive to the stable operation of the pipeline fan 100, and also helps to avoid looseness or oil leakage at the connection, thereby improving the overall reliability of the pipeline fan 100.

[0055] There are at least two structural forms of the outlet transfer section 13:

[0056] The first one is that the bottom end of the outlet adapter section 13 for oil flow is extended in the horizontal direction along the flow direction X of the oil fume, that is, the bottom end of the outlet adapter section 13 and the bottom end of the main section 11 are kept at the same horizontal position, so that the oil will not encounter a height difference when flowing in the pipeline fan 100, which is conducive to the smooth discharge of the oil;

[0057] The second type is that along the flow direction X of the oil smoke, the bottom height of the outlet transition section 13 for oil flow in its radial direction gradually decreases, that is, the oil can have a natural inclined route, which is more conducive to the smooth flow of the oil and discharge of the pipeline fan 100, and prevents the accumulation of oil from causing blockage.

[0058] In general, whether the bottom end is extended in the horizontal direction or the bottom end height is gradually lowered, it is to optimize the flow and drainage of oil smoke in the duct fan 100, thereby improving the exhaust efficiency and stability of the duct fan 100.

[0059] In this embodiment, if Figure 1 and Figure 2 As shown, the bottom end of the outlet transition section 13 for oil flow and the bottom end of the main section 11 are at the same level, that is, the first structural form mentioned above, and the inner diameter of the connection between the outlet transition section 13 and the main section 11 is the same as the inner diameter of the main section 11 and its inner diameter gradually decreases along the flow direction X of the oil smoke.

[0060] In this embodiment, the bottom end of the outlet adapter section 13 is at the same level as the bottom end of the main section 11, ensuring that the flow of oil in the duct fan 100 will not be affected by the height difference, which is conducive to the smooth discharge of oil. The inner diameter of the connection between the outlet adapter section 13 and the main section 11 is the same as the inner diameter of the main section 11, and the inner diameter gradually decreases along the flow direction X of the oil smoke. This design helps to accelerate the flow rate of oil smoke in the duct fan 100, thereby enhancing the effect of oil discharge, and in the process of gradually reducing the inner diameter, it can also more effectively bring the oil into the oil discharge port, reducing the possibility of liquid accumulation.

[0061] In other embodiments, the structural form of the outlet adapter section 13 can be set as needed, as long as it can satisfy the smooth discharge of the oil in the duct fan 100, and it belongs to the protection scope of this application.

[0062] Preferably, the inlet adapter section 12 and / or the outlet adapter section 13 are threadedly connected to the main section 11. The threaded connection can not only ensure that the connection between the inlet adapter section 12 and the outlet adapter section 13 and the main section 11 is tighter, thereby effectively preventing air and oil fume leakage, but also avoid oil leakage and other problems, thereby improving the sealing of the duct fan 100. In addition, the threaded connection provides a more secure connection method, which can resist the vibration and pressure generated during the operation of the duct fan 100, reduce the possibility of loosening of the connection part, and improve the stability and reliability of the duct fan 100. In addition, the threaded connection is easier to install and disassemble than other connection methods (such as flange connection), which makes the maintenance and cleaning of the duct fan 100 more convenient and quick, saving maintenance costs and time.

[0063] like Figure 2 and Figure 3 As shown, a first tooth structure 14 is provided on the inner wall surface at the connection between the inlet transition section 12 and / or the outlet transition section 13 and the main body section 11, and a second tooth structure is provided on the outer wall surface of the main body section 11 corresponding to the first tooth structure 14, so as to realize the movable connection between the inlet transition section 12 and / or the outlet transition section 13 and the main body section 11.

[0064] Among them, the design of the first tooth structure 14 and the second tooth structure enables the inlet adapter section 12 and / or the outlet adapter section 13 to be movably connected with the main section 11, which not only ensures the stability of the connection, prevents the connection part from loosening or falling off, and ensures the safe and stable operation of the duct fan 100, but also can achieve a sealing effect between the inlet adapter section 12 and / or the outlet adapter section 13 and the main section 11 to avoid air leakage, oil leakage, etc. In addition, it can also allow the duct fan 100 to adjust the angle or position within a certain range, increasing the flexibility of the duct fan 100 to meet the requirements of the installation environment or the needs of actual operation.

[0065] At the same time, a stopper 112 is also provided on the outer wall surface of the main body section 11, and the stopper 112 is located on the side of the second tooth structure away from the inlet adapter section 12 and / or the outlet adapter section 13, and the extension direction of the stopper 112 is perpendicular to the axial direction of the main body section 11. By setting the stopper 112, the overlap range of the inlet adapter section 12 and / or the outlet adapter section 13 connected to the main body section 11 can be effectively limited, and this position limitation can ensure that the inlet adapter section 12 and / or the outlet adapter section 13 are connected to the correct position of the main body section 11, so as to ensure the normal operation of the duct fan 100.

[0066] like Figure 4 and Figure 5 As shown, a stop member 113 is also provided on the second tooth structure at one end of the main body section 11 near the outlet transition section 13. The stop member 113 is arranged along the axial extension direction of the main body section 11, and the height of the stop member 113 along the radial direction of the main body section 11 is lower than the height of the central axis of the main body section 11.

[0067] In this embodiment, the setting of the stopper 113 limits the moving range of the outlet adapter section 13 on the main section 11, thereby ensuring that the outlet adapter section 13 is in the correct position. Specifically, along the radial direction of the outlet adapter section 13, the center axis height of the outlet adapter section 13 is ensured to be lower than the center axis height of the main section 11, and the outlet adapter section 13 is ensured to be eccentric relative to the main section 11, so as to ensure that the bottom end height of the outlet adapter section 13 for oil flow is not higher than the height of the connection between the outlet adapter section 13 and the main section 11, thereby ensuring the smooth discharge of the oil.

[0068] like Figure 2 As shown, the duct fan 100 also includes a fan assembly 15 disposed in the main body section 11. This arrangement utilizes the internal space of the duct fan 100, making the structure of the entire duct fan 100 more compact and optimizing the space utilization efficiency to the maximum extent. At the same time, the fan assembly 15 also includes an impeller 151, and the central axis of the impeller 151 is the same as the central axis of the main body section 11. This arrangement ensures that the impeller 151 is aligned with the axis of the pipeline during operation, which not only reduces the vibration and noise caused by offset or imbalance, but also makes the operation of the impeller 151 more stable, reduces energy loss, and improves the stability of the operation of the fan assembly 15.

[0069] The present application also discloses another embodiment: a range hood device, comprising a range hood and the above-mentioned duct fan 100. Specifically, the duct fan 100 is arranged at the rear end of the range hood along the oil fume flow direction X, and is connected to the smoke pipe of the range hood through the inlet adapter section 12.

[0070] In this embodiment, the duct fan 100 is arranged at the rear end of the range hood along the oil fume flow direction, which can increase additional wind suction after the oil fume passes through the range hood, improve the efficiency of oil fume suction, effectively enhance the oil suction capacity of the range hood, and improve the oil fume purification effect. In addition, the duct fan 100 is connected to the smoke pipe of the range hood through the inlet adapter section 12, ensuring an effective connection between the two, avoiding air leakage or oil leakage, ensuring a close fit between the range hood and the duct fan 100, and making the entire range hood device run more stably.

[0071] Although the specific implementations of the utility model are described above, those skilled in the art should understand that this is only an example, and the protection scope of the utility model is defined by the attached claims. Those skilled in the art can make various changes or modifications to these implementations without departing from the principle and essence of the utility model, but these changes and modifications fall within the protection scope of the utility model.

Claims

1. A duct fan, characterized in that: The duct fan is horizontally extended to allow the oil smoke to circulate in a horizontal direction. The duct fan includes a main section and an inlet transition section and an outlet transition section arranged at both ends of the main section along the flow direction of the oil smoke, wherein the inlet transition section is connected to the smoke pipe of the range hood, and the bottom end height of the outlet transition section along its radial direction for the oil liquid to circulate is not higher than the bottom end height of the connection between it and the main section.

2. The duct fan according to claim 1, characterized in that: Along the flow direction of the oil smoke, the bottom end of the outlet adapter section for oil liquid flow is extended in the horizontal direction; Alternatively, the height of the bottom end of the outlet transition section for oil flow gradually decreases along the radial direction thereof.

3. The duct fan according to claim 1, characterized in that: The bottom end of the outlet transition section for oil flow and the bottom end of the main section are at the same level, the inner diameter of the connection between the outlet transition section and the main section is the same as the inner diameter of the main section and its inner diameter gradually decreases along the flow direction of the oil smoke.

4. The duct fan according to claim 1, characterized in that: The inlet transition section and / or the outlet transition section are threadedly connected to the main body section.

5. The duct fan according to claim 1 or 4, characterized in that: A first tooth structure is provided on the inner wall surface at the connection between the inlet transition section and / or the outlet transition section and the main body section, and a second tooth structure is provided on the outer wall surface of the main body section corresponding to the first tooth structure, so as to realize the movable connection between the inlet transition section and / or the outlet transition section and the main body section.

6. The duct fan according to claim 5, characterized in that: A limiting member is provided on the outer wall surface of the main body section, and the limiting member is located on a side of the second toothed structure away from the inlet transition section and / or the outlet transition section; The extending direction of the limiting member is perpendicular to the axial direction of the main body section.

7. The duct fan according to claim 5, characterized in that: A stopper is provided on the second toothed structure at one end of the main body section near the outlet transition section. The stopper is arranged along the axial extension direction of the main body section, and the height of the stopper along the radial direction of the main body section is lower than the height of the central axis of the main body section.

8. The duct fan according to claim 1, characterized in that: The main body section has a constant inner diameter along the flow direction of the oil smoke; And / or, the inner diameter of the inlet transition section gradually increases along the flow direction of the oil smoke, and the inner diameter of the connection between the inlet transition section and the main body section is the same as the inner diameter of the main body section.

9. The duct fan according to claim 1, characterized in that: The duct fan further comprises a fan assembly, wherein the fan assembly is arranged in the main body section; The fan assembly comprises an impeller, and a central axis of the impeller is the same as a central axis of the main body section.

10. A range hood device, characterized in that: The range hood device comprises a range hood and the duct fan according to any one of claims 1 to 9, wherein the duct fan is arranged at the rear end of the range hood along the oil fume flow direction and is connected to the smoke duct of the range hood through the inlet adapter section.

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