Axial flow fan with air inlet box

Abstract

The axial flow fan comprises the air inlet box connected with the air inlet end of the axial flow fan, the air inlet box comprises a shell, and an air inlet of the shell is connected with an external air duct through a flexible connecting piece; a monitoring assembly for blocking the air flow from making contact with the flexible connecting piece and monitoring the air flow state in real time is movably arranged on the inner side of the flexible connecting piece, and the monitoring assembly is located on the air flow path. Air flow can be prevented from flowing along the flexible expansion belt, and the influence on the air flow when the flexible expansion belt is wrinkled can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of axial flow fans, and in particular to an axial flow fan with an air inlet box. Background Art

[0002] With the rapid development of the fan industry, large axial flow fans are widely used as blowers, induced draft fans, primary fans in power plants, and booster fans used in flue gas desulfurization. In the application process, large axial flow fans are equipped with air inlet boxes. When the air inlet box is connected to the external air duct, it is necessary to configure an expansion joint to compensate for the displacement error of on-site installation. However, during use, the expansion joint will be arched or wrinkled due to compression. For an ideal flow channel, the flow channel wall should be smooth and fluent. The deformation of the expansion joint during use due to compensation displacement will inevitably affect the internal flow field and the aerodynamic performance of the fan. Summary of the invention

[0003] The object of the present invention is to provide an axial flow fan with an air inlet box, which can prevent air flow from flowing along a flexible expansion belt and reduce the impact on the air flow when the flexible expansion belt is wrinkled.

[0004] In order to solve the above technical problems, the present invention adopts the following solutions: An axial flow fan with an air intake box comprises an air intake box connected to the air intake end of the axial flow fan, the air intake box comprises a shell, the air intake port of the shell is connected to an external air duct through a flexible connector, a monitoring component is movably provided on the inner side of the flexible connector for blocking the airflow from contacting the flexible connector and monitoring the airflow state in real time, and the monitoring component is located on the airflow path.

[0005] In this solution, the air intake box is directly connected to the air intake end of the axial flow fan, ensuring smooth entry of airflow. This design enables the axial flow fan to work efficiently while reducing airflow losses caused by improper connection. The flexible connector can compensate for the displacement error of on-site installation, but during use, the flexible connector may be arched or wrinkled due to long-term expansion and contraction. The monitoring component on the air intake path can block the contact path between the airflow and the flexible connector, avoiding the airflow from flowing along the flexible connector, reducing the impact on the airflow when the flexible connector is arched or wrinkled, and ensuring the smoothness of the airflow flow channel; at the same time, the monitoring component can monitor the state of the airflow in real time, and can promptly know when turbulence occurs in the airflow, so as to adjust the airflow, reduce the impact of turbulence on the axial flow fan, and ensure the aerodynamic performance of the axial flow fan.

[0006] Optionally, the monitoring component includes a wedge plate and a force measuring element. The wedge plate is movably arranged on the inner side of the air inlet and blocks the airflow from contacting the flexible connector. One side of the wedge plate is an inclined straight surface, and the other side is a flat surface opposite to the inclined straight surface. The lower side of the flat surface is in contact with the inner wall of the shell. The force measuring element is arranged between the wedge plate and the inner wall of the shell. The airflow acts on the inclined straight surface and squeezes the force measuring element through the wedge plate.

[0007] Optionally, the air inlet is rectangular in shape, and a bending edge integrally formed with the shell is provided around the air inlet, the bending edge is located on the outside of the shell, the lower end of the flexible connector is connected to the side of the bending edge, a fixing plate connected to an external pipeline is provided above the bending edge, the fixing plate is L-shaped, the upper end of the flexible connector is connected to the side of the fixing plate, the top of the wedge plate is movably connected to a mounting plate, and the mounting plate is connected to the bottom surface of the fixing plate.

[0008] Optionally, the force measuring element is a resistive strain gauge pressure sensor, and the force measuring element is embedded in the inner wall of the shell.

[0009] Optionally, the wedge-shaped plates are distributed around the air inlet, and two adjacent wedge-shaped plates are connected by a flexible cloth, which is a flexible glass fiber cloth coated with sealant.

[0010] Optionally, the upper portion of the wedge-shaped plate has a cavity inside, and the lower portion is a solid structure, and the center of gravity of the wedge-shaped plate is located at the lower end thereof.

[0011] Optionally, the cavity is filled with sound insulation cotton.

[0012] Optionally, a sound insulation cavity is formed between the flexible connector and the wedge plate, the top of the bent edge, and the mounting plate, and the sound insulation cavity is filled with sound insulation material.

[0013] Optionally, the flexible connector is a flexible expansion belt, the upper end of which is mounted on the side of the fixed plate via a pressure plate, the lower end of which is mounted on the side of the bent edge via a pressure plate, and the pressure plate is fixed to the mounting plate and the bent edge via bolts.

[0014] Optionally, the side of the wedge plate in contact with the inner wall of the shell is coated with a rubber layer, and the upper end of the wedge plate is connected to the mounting plate via an arc-shaped rubber plate.

[0015] The present invention has the beneficial effects: In the present invention, the monitoring component on the air intake path can block the contact path between the airflow and the flexible connector, thereby preventing the airflow from flowing along the flexible connector, reducing the impact on the airflow when the flexible connector is arched or wrinkled, and ensuring the smoothness of the airflow flow channel; at the same time, the monitoring component can monitor the state of the airflow in real time, and can promptly know when turbulence occurs in the airflow, so as to adjust the airflow, reduce the impact of turbulence on the axial flow fan, and ensure the aerodynamic performance of the axial flow fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 This is a schematic diagram of the structure when the sound insulation cavity and the cavity are not filled with sound insulation cotton; Figure 3 It is a schematic diagram of the structure when adjacent wedge-shaped plates are connected by flexible cloth; Figure 4 Schematic diagram of the force decomposition of the airflow impact force on the wedge plate.

[0017] Figure numerals: 1-shell, 2-rubber layer, 3-force measuring element, 4-flexible expansion belt, 5-pressure plate, 6-fixing plate, 7-rubber plate, 8-air inlet, 9-transition surface, 10-rubber membrane, 11-wedge plate, 12-mounting plate, 13-sound insulation cotton, 14-bent edge, 15-sound insulation cavity, 16-cavity, 17-flexible cloth. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0019] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0020] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] An axial flow fan with an air intake box comprises an air intake box connected to the air intake end of the axial flow fan, the air intake box comprises a shell 1, an air intake port 8 of the shell 1 is connected to an external air duct via a flexible connector, a monitoring component is movably provided inside the flexible connector for blocking the airflow from contacting the flexible connector and for monitoring the airflow status in real time, and the monitoring component is located on the airflow path.

[0022] In this embodiment, Figure 1 As shown, the air intake box is directly connected to the air intake end of the axial flow fan, ensuring smooth entry of the airflow. This design enables the axial flow fan to work efficiently while reducing airflow losses caused by improper connection. The flexible connector can compensate for the displacement error of on-site installation, but during use, the flexible connector may be arched or wrinkled due to long-term expansion and contraction. The monitoring component on the air intake path can block the contact path between the airflow and the flexible connector, avoiding the airflow from flowing along the flexible connector, reducing the impact on the airflow when the flexible connector is arched or wrinkled, and ensuring the smoothness of the airflow flow channel; at the same time, the monitoring component can monitor the state of the airflow in real time, and can promptly know when turbulence occurs in the airflow, so as to adjust the airflow, reduce the impact of turbulence on the axial flow fan, and ensure the aerodynamic performance of the axial flow fan.

[0023] Furthermore, the monitoring component includes a wedge plate 11 and a force measuring element 3. The wedge plate 11 is movably arranged on the inner side of the air inlet 8 and blocks the airflow from contacting the flexible connector. One side of the wedge plate 11 is an inclined straight surface, and the other side is a flat surface opposite to the inclined straight surface. The lower side surface of the flat surface is attached to the inner wall of the shell 1. The force measuring element 3 is arranged between the wedge plate 11 and the inner wall of the shell 1. The airflow acts on the inclined straight surface and squeezes the force measuring element 3 through the wedge plate 11.

[0024] Specifically, the wedge plate 11 is movably arranged inside the air inlet 8. The wedge plate 11 has a certain range of movement in both the vertical and horizontal directions. Its main function is to block the direct contact between the airflow and the flexible connector, thereby reducing the impact on the airflow when the flexible connector is arched or wrinkled, ensuring the smoothness of the airflow channel. One side of the wedge plate 11 is designed as an oblique straight surface, and the other side is a flat surface opposite to the oblique straight surface. When the airflow acts on the oblique straight surface, the flow direction of the airflow is vertical, such as Figure 4As shown, the impact force generated on the inclined plane will be decomposed into a lateral force. The lateral force is horizontal and perpendicular to the shell 1. The lateral force pushes the wedge plate 11 to move toward the inner wall of the shell 1. The force measuring element 3 senses this lateral force and generates a signal and outputs it to the controller. The controller measures and records the lateral force on the wedge plate 11 in real time. By monitoring the size and change of this lateral force, the state and intensity of the airflow can be indirectly understood. If the airflow is relatively smooth, the thrust change fluctuation monitored by the controller is small. At this time, the axial flow fan can continue to operate according to the current working conditions. If the monitored lateral force change fluctuation is large and has exceeded the threshold range, it can be To determine that turbulence has occurred in the airflow, it is necessary to adjust the operating state of the fan in time or stop running, or manually intervene in the airflow to avoid turbulence. The inclined straight surface of the wedge plate 11 is a smooth surface, which can reduce the occurrence of turbulence. At the same time, the lateral force can press the wedge plate 11 tightly against the inner wall of the shell 1, so that the wedge plate 11 fits tightly against the inner wall of the shell 1, better blocking the path of the airflow contacting the flexible connector. The lower side surface of the flat surface is fitted against the inner wall of the shell 1. The width of the wedge plate 11 is basically the same as that of the inner wall of the shell 1. Multiple wedge plates 11 also form a funnel-shaped guide structure, which can guide the gas to the air inlet end of the axial flow fan.

[0025] Working principle: When the airflow acts on the oblique surface of the wedge plate 11, the wedge plate 11 will be subjected to a lateral thrust. The force measuring element 3 can accurately measure the magnitude of this thrust and convert it into an electrical signal or other readable form for real-time monitoring and analysis. When the axial flow fan is running, the airflow enters from the air inlet 8, and the impact force of the airflow acts on the oblique surface of the wedge plate 11. Due to the design of the oblique surface, the impact force of the airflow will generate a lateral thrust, pushing the wedge plate 11 to press against the inner wall of the housing 1. In this process, the force measuring element 3 will measure and record the magnitude of the lateral force on the wedge plate 11. By monitoring the magnitude and changes of this lateral force, the state and strength of the airflow can be indirectly understood, including the velocity and flow rate of the airflow, and whether there are abnormal fluctuations.

[0026] Real-time monitoring: Through the real-time monitoring function of the force measuring element 3, abnormal changes in the airflow state can be discovered in time, providing strong data support for the operation and maintenance of the fan.

[0027] Improve fan performance: By monitoring the airflow status, the fan operating parameters can be adjusted in time to ensure that it always operates in the best condition, thereby improving the overall performance of the fan.

[0028] Furthermore, the air inlet 8 is rectangular in shape, and is circumferentially provided with a bending edge 14 integrally formed with the shell 1, the bending edge 14 is located on the outside of the shell 1, the lower end of the flexible connector is connected to the side of the bending edge 14, and a fixing plate 6 connected to the external pipeline is provided above the bending edge 14, the fixing plate 6 is L-shaped, the upper end of the flexible connector is connected to the side of the fixing plate 6, the top of the wedge plate 11 is movably connected to the mounting plate 12, and the mounting plate 12 is connected to the bottom surface of the fixing plate 6.

[0029] Specifically, the air inlet 8 is designed to be rectangular, which is conducive to the uniform distribution of airflow and reduces the formation of vortices, thereby improving the efficiency of the fan. Figure 1 As shown, the air inlet 8 is circumferentially provided with a bending edge 14 integrally formed with the shell 1. This design not only enhances the structural strength of the air inlet 8, but also provides a stable interface connected to the flexible connector. The bending edge 14 is L-shaped, and the lower end of the flexible connector is connected to the side of the bending edge 14. A fixing plate 6 connected to the external pipeline is provided above the bending edge 14. The fixing plate 6 is L-shaped, and the top of the wedge plate 11 is movably connected to the mounting plate 12. This design enables the wedge plate 11 to have a certain displacement ability, and can move vertically following the extension and contraction of the flexible connector, and can move toward the inner wall of the shell 1 under the action of lateral force. At the same time, the mounting plate 12 provides stable support for the wedge plate 11, and the mounting plate 12 is connected to the bottom surface of the fixing plate 6. Such a layout ensures the stability and accuracy of the monitoring component.

[0030] When the air flow passes through the air inlet 8, it acts on the inclined straight surface of the wedge plate 11, pushing the wedge plate 11 to move, and records the force changes in this process through the force measuring element 3. This design allows real-time monitoring of the state of the air flow, including key parameters such as flow velocity and flow rate, so as to detect air flow turbulence in a timely manner.

[0031] Furthermore, the force measuring element 3 is a resistive strain gauge pressure sensor, and the force measuring element 3 is embedded in the inner wall of the housing 1 .

[0032] Specifically, the resistive strain type pressure sensor is thin and small in size, and can be embedded in the inner wall of the shell 1. The pressure sensing end of the resistive strain type pressure sensor faces the flat surface of the wedge plate 11, so that when the wedge plate 11 receives the lateral thrust of the airflow, it can squeeze the resistive strain type pressure sensor against the inner wall of the shell 1. At the same time, in order to avoid airflow leakage in the installation gap, sealant is applied around the resistive strain type pressure sensor.

[0033] Furthermore, the wedge-shaped plates 11 are distributed around the air inlet 8 , and two adjacent wedge-shaped plates 11 are connected by a flexible cloth 17 , which is a flexible glass fiber cloth coated with a sealant.

[0034] Specifically, the wedge plates 11 are distributed around the air inlet 8. Such a layout ensures that the airflow in all directions of the air inlet 8 can be effectively monitored. Each wedge plate 11 has the function of blocking the direct contact between the airflow and the flexible connector, and monitors the airflow state in real time through the force measuring element 3. This distribution method not only improves the accuracy and comprehensiveness of monitoring, but also enhances the structural strength of the air inlet box. Figure 3 As shown, two adjacent wedge plates 11 are connected by a flexible glass fiber cloth. The flexible glass fiber cloth has the advantages of high strength, corrosion resistance, wear resistance and high temperature resistance, and can maintain stable performance in harsh environments. In addition, its flexibility enables the wedge plate 11 to move freely under the action of airflow without being restricted by the connector. Coating sealant on the flexible glass fiber cloth can further enhance the sealing performance of the connection. The sealant can fill the tiny gaps at the connection to prevent airflow leakage, thereby improving the sealing and efficiency of the air intake box.

[0035] Comprehensive monitoring: by distributing the wedge-shaped plates 11 around the air inlet 8, comprehensive monitoring of the airflow state is achieved, thereby improving the accuracy and reliability of the monitoring.

[0036] Enhanced sealing: The combination of flexible fiberglass cloth and sealant ensures the tightness of the air intake box connection, reducing airflow leakage and energy loss.

[0037] Improved flexibility: The flexibility of the flexible glass fiber cloth enables the wedge plate 11 to move freely under the action of the airflow, thereby improving the flexibility and adaptability of the air intake box.

[0038] Enhanced structural strength: Through the distribution and connection of the wedge-shaped plates 11 and the flexible glass fiber cloth, the overall structural strength of the air intake box is enhanced, and it is capable of withstanding greater airflow pressure and external loads.

[0039] Furthermore, the upper portion of the wedge-shaped plate 11 has a cavity 16 inside, and the lower portion is a solid structure, and the center of gravity of the wedge-shaped plate 11 is located at the lower end thereof.

[0040] Furthermore, the cavity 16 is filled with sound insulation cotton 13 .

[0041] Specifically, Figure 2As shown, the upper part of the wedge plate 11 has a cavity 16 inside. This design effectively reduces the weight of the wedge plate 11, and the cavity 16 also provides space for filling the sound insulation cotton 13. The lower part of the wedge plate 11 is a solid structure, so that the center of gravity of the wedge plate 11 is located at its lower end. Such a layout makes it easier for the wedge plate 11 to maintain balance and stability when it is affected by airflow, reducing the noise and wear caused by shaking, and also making the wedge block better fit on the inner wall of the shell 1. Filling the cavity 16 of the wedge plate 11 with sound insulation cotton 13 can significantly improve the sound insulation effect of the air intake box. The sound insulation cotton 13 can absorb and reflect the noise generated by the airflow, reduce the interference of noise on the surrounding environment, and improve the overall performance of the fan. The sound insulation cotton 13 also has a certain thermal insulation performance, which can reduce the temperature loss of the airflow when passing through the air intake box and improve the energy efficiency of the fan.

[0042] Furthermore, a sound insulation cavity 15 is formed between the flexible connector, the wedge plate 11 , the top of the bent edge 14 , and the mounting plate 12 , and the sound insulation cavity 15 is filled with sound insulation material.

[0043] Specifically, Figure 2 As shown, the sound insulation cavity 15 is surrounded by a flexible connector, a wedge plate 11, a top of a bent edge 14 and a mounting plate 12. The close fit between these components ensures the sealing of the sound insulation cavity 15 and prevents noise leakage. The sound insulation cavity 15 is filled with sound insulation material, which can be fixed in the sound insulation cavity 15 by bonding. The sound insulation material can be sound insulation cotton 13, sound insulation foam, etc. These materials have excellent sound absorption and sound insulation properties, can effectively absorb and reflect noise, and reduce its propagation distance and intensity.

[0044] The combined use of the sound insulation cavity 15 and the sound insulation material significantly improves the sound insulation effect of the air intake box. This design can effectively reduce the interference of the noise generated by the fan during operation on the surrounding environment and improve the overall acoustic performance.

[0045] Furthermore, the flexible connecting member is a flexible expansion belt 4, the upper end of which is installed on the side of the fixed plate 6 through a pressure plate 5, and the lower end of which is installed on the side of the bending edge 14 through a pressure plate 5. The pressure plate 5 is fixed to the mounting plate 12 and the bending edge 14 by bolts.

[0046] Furthermore, the side of the wedge plate 11 in contact with the inner wall of the housing 1 is coated with a rubber layer 2 , and the upper end of the wedge plate 11 is connected to the mounting plate 12 via an arc-shaped rubber plate 7 .

[0047] Specifically, the side of the wedge plate 11 that contacts the inner wall of the shell 1 is coated with a rubber layer 2. This design significantly enhances the sealing between the two. The rubber layer 2 can fill the tiny gap between the wedge plate 11 and the inner wall of the shell 1 to prevent airflow leakage and ensure the sealing performance of the air intake box. The rubber layer 2 also has a certain elasticity and lubricity, which can reduce the friction and wear between the wedge plate 11 and the inner wall of the shell 1 during movement, thereby extending the service life of the air intake box.

[0048] In order to further prevent gas from escaping into the soundproof cavity 15, an arc-shaped rubber membrane 10 is provided at the bottom of the wedge plate 11. The rubber membrane 10 is attached to the inner wall of the shell 1. Under the action of the air pressure inside the shell 1, the rubber membrane 10 is pressed against the inner wall of the shell 1, thereby further blocking the path between the airflow and the soundproof cavity 15. The rubber membrane 10 is large at the upper end and small at the lower end, and the outer surface is an arc-shaped surface. The connection with the wedge plate 11 is an arc-shaped transition surface 9, so that the fluidity of the airflow is better. The wedge plates 11 and the rubber membrane 10 on all sides form a variable diameter flow channel. The wedge plates 11 and the rubber membrane 10 with a certain length can provide a buffer zone for the fluid to enter or exit, which helps the airflow to transition smoothly, reduce the changes in pressure and speed, and reduce the probability of turbulence.

[0049] like Figure 2 As shown, the upper end of the wedge plate 11 is connected to the mounting plate 12 via an arc-shaped rubber plate 7. This design increases the flexibility of the connection. The arc-shaped rubber plate 7 can adapt to the slight displacement of the wedge plate 11 under the action of airflow, ensuring the stability and reliability of the connection. The arc-shaped rubber plate 7 also has certain shock absorption and noise reduction functions. It can absorb and disperse the vibration and noise generated when the wedge plate 11 moves, reducing the impact of these adverse factors on the air intake box and the surrounding environment.

[0050] Improved sealing performance: The coating of the rubber layer 2 and the use of the arc-shaped rubber plate 7 together improve the sealing performance of the air intake box, reduce airflow leakage, and improve energy efficiency.

[0051] Enhanced stability: These designs enhance the connection stability between the wedge plate 11 and the inner wall of the housing 1 and between the upper end of the wedge plate 11 and the mounting plate 12, thereby ensuring the reliability of the air intake box during long-term operation.

[0052] Noise reduction and vibration reduction: The elastic properties of the rubber layer 2 and the arc-shaped rubber plate 7 help to reduce the transmission of vibration and noise, thereby improving the acoustic performance of the air intake box.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. An axial flow fan with an air inlet box, comprising an air inlet box connected to the air inlet end of the axial flow fan, characterized in that: The air inlet box comprises a shell (1), an air inlet (8) of the shell (1) being connected to an external air duct via a flexible connector, a monitoring component being movably provided inside the flexible connector for blocking the airflow from contacting the flexible connector and for monitoring the airflow state in real time, the monitoring component being located on the airflow path.

2. An axial flow fan with an air inlet box according to claim 1, characterized in that: The monitoring assembly comprises a wedge plate (11) and a force measuring element (3); the wedge plate (11) is movably arranged inside the air inlet (8) and blocks the airflow from contacting the flexible connecting piece; one side of the wedge plate (11) is an oblique straight surface, and the other side is a flat surface opposite to the oblique straight surface; the lower side surface of the flat surface is in contact with the inner wall of the housing (1); the force measuring element (3) is arranged between the wedge plate (11) and the inner wall of the housing (1); the airflow acts on the oblique straight surface and compresses the force measuring element (3) through the wedge plate (11).

3. The axial flow fan with an air inlet box according to claim 2, characterized in that: The air inlet (8) is rectangular in shape, and is provided with a bending edge (14) formed integrally with the shell (1) in the circumferential direction of the air inlet (8), the bending edge (14) being located outside the shell (1), the lower end of the flexible connector being connected to the side of the bending edge (14), a fixing plate (6) connected to an external pipe being provided above the bending edge (14), the fixing plate (6) being L-shaped, the upper end of the flexible connector being connected to the side of the fixing plate (6), the top end of the wedge-shaped plate (11) being movably connected to a mounting plate (12), and the mounting plate (12) being connected to the bottom surface of the fixing plate (6).

4. The axial flow fan with an air inlet box according to claim 2, characterized in that: The force measuring element (3) is a resistance strain type pressure sensor, and the force measuring element (3) is embedded in the inner wall of the housing (1).

5. The axial flow fan with an air inlet box according to claim 2, characterized in that: The wedge-shaped plates (11) are distributed around the air inlet (8), and two adjacent wedge-shaped plates (11) are connected by a flexible cloth (17). The flexible cloth (17) is a flexible glass fiber cloth, and the flexible cloth (17) is coated with a sealant.

6. The axial flow fan with an air inlet box according to claim 2, characterized in that: The upper part of the wedge-shaped plate (11) has a cavity (16) inside, and the lower part is a solid structure, and the center of gravity of the wedge-shaped plate (11) is located at the lower end thereof.

7. An axial flow fan with an air inlet box according to claim 6, characterized in that: The cavity (16) is filled with sound insulation cotton (13).

8. The axial flow fan with an air inlet box according to claim 3, characterized in that: A sound insulation cavity (15) is formed between the flexible connecting piece and the wedge-shaped plate (11), the top of the bent edge (14), and the mounting plate (12), and the sound insulation cavity (15) is filled with sound insulation material.

9. The axial flow fan with an air inlet box according to claim 3, characterized in that: The flexible connecting member is a flexible expansion belt (4), the upper end of the flexible expansion belt (4) is mounted on the side of the fixing plate (6) through a pressing plate (5), the lower end of the flexible expansion belt (4) is mounted on the side of the bending edge (14) through a pressing plate (5), and the pressing plate (5) is fixed to the mounting plate (12) and the bending edge (14) by bolts.

10. The axial flow fan with an air inlet box according to claim 2, characterized in that: The side of the wedge plate (11) in contact with the inner wall of the housing (1) is coated with a rubber layer (2), and the upper end of the wedge plate (11) is connected to the mounting plate (12) via an arc-shaped rubber plate (7).

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