An axial flow fan with an air inlet box

Abstract

The present invention discloses an axial flow fan with an air inlet box, which includes an air inlet box connected to the air inlet end of the axial flow fan. The air inlet box includes a housing, and the air inlet of the housing is connected to an external air duct through a flexible connector. Inside the flexible connector, a monitoring component is movably provided to block the contact between the air flow and the flexible connector and to monitor the air flow state in real time. The monitoring component is located on the air flow path. The present invention can prevent the air flow from flowing along the flexible expansion band, and can reduce the influence on the air flow when the flexible expansion band is wrinkled.

Description

Technical Field

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

[0002] With the rapid development of the fan industry, large axial fans are widely used as forced draft fans, induced draft fans, and primary fans in power plants, as well as booster fans used in flue gas desulfurization. During application, large axial fans are all equipped with air inlet boxes, and expansion joints need to be configured when the air inlet boxes are connected to external air ducts to compensate for the displacement error in on-site installation. However, during use, the expansion joints will arch or wrinkle due to compression. For an ideal flow channel, the flow channel wall should be smooth and unobstructed. The deformation of the expansion joints during use due to displacement compensation will inevitably affect the internal flow field and the aerodynamic performance of the fan. Summary of the Invention

[0003] The purpose of the present invention is to provide an axial fan with an air inlet box, which can avoid the flow of air along the flexible expansion band and reduce the influence on the air flow when the flexible expansion band wrinkles.

[0004] To solve the above technical problems, the present invention adopts the following solutions:

[0005] An axial fan with an air inlet box includes an air inlet box connected to the air inlet end of the axial fan. The air inlet box includes a housing. The air inlet of the housing is connected to an external air duct through a flexible connector. Inside the flexible connector, a monitoring component is movably provided to block the contact between the air flow and the flexible connector and to monitor the state of the air flow in real time. The monitoring component is located on the air flow path.

[0006] In this solution, the air inlet box is directly connected to the air inlet end of the axial fan, ensuring the smooth entry of the air flow. This design enables the axial fan to operate efficiently while reducing the air flow loss caused by improper connection. The flexible connector can compensate for the displacement error in on-site installation. However, during use, the flexible connector will arch or wrinkle due to long-term expansion and contraction. The monitoring component on the air inlet path can block the contact path between the air flow and the flexible connector, avoiding the flow of air along the flexible connector, and reducing the influence on the air flow when the flexible connector arches or wrinkles, ensuring the smoothness of the air flow channel. At the same time, the monitoring component can monitor the state of the air flow in real time, and can be aware of it in time when the air flow becomes turbulent, so as to adjust the air flow and reduce the influence of the turbulence on the axial fan, and ensure the aerodynamic performance of the axial fan.

[0007] Optionally, the monitoring component includes a wedge plate and a force measuring element. The wedge plate is movably arranged inside the air inlet and blocks the contact between the air flow and the flexible connecting piece. One side of the wedge plate is an inclined plane, and the other side is a flat plane opposite to the inclined plane. The lower side of the flat plane is attached to the inner wall of the housing. The force measuring element is arranged between the wedge plate and the inner wall of the housing. The air flow acts on the inclined plane and squeezes the force measuring element through the wedge plate.

[0008] Optionally, the air inlet is rectangular. A bent edge integrally formed with the housing is provided around the air inlet. The bent edge is located outside the housing. The lower end of the flexible connecting piece is connected to the side surface of the bent edge. An fixing plate connected to an external pipeline is provided above the bent edge. The fixing plate is L-shaped. The upper end of the flexible connecting piece is connected to the side surface of the fixing plate. The top end of the wedge plate is movably connected to an mounting plate, and the mounting plate is connected to the bottom surface of the fixing plate.

[0009] Optionally, the force measuring element is a resistance strain type pressure sensor, and the force measuring element is embedded in the inner wall of the housing.

[0010] Optionally, the wedge plates are distributed around the air inlet. Flexible cloth is connected between adjacent two wedge plates. The flexible cloth is flexible fiberglass cloth, and sealant is coated on the flexible cloth.

[0011] Optionally, the upper part inside the wedge plate has a cavity, and the lower part is a solid structure. The center of gravity of the wedge plate is located at its lower end.

[0012] Optionally, the cavity is filled with sound insulation cotton.

[0013] Optionally, a sound insulation cavity is formed among the flexible connecting piece, the top of the bent edge and the mounting plate, and the sound insulation cavity is filled with sound insulation material.

[0014] Optionally, the flexible connecting piece is a flexible expansion band. The upper end of the flexible expansion band is installed on the side surface of the fixing plate through a pressing plate, and the lower end of the flexible expansion band is installed on the side surface of the bent edge through a pressing plate. The pressing plate is fixed to the mounting plate and the bent edge through bolts.

[0015] Optionally, the side surface of the wedge plate in contact with the inner wall of the housing is coated with a rubber layer, and the upper end of the wedge plate is connected to the mounting plate through an arc-shaped rubber plate.

[0016] The beneficial effects of the present invention are as follows:

[0017] In the present invention, the monitoring component on the air inlet path can block the contact path between the air flow and the flexible connecting piece, avoid the air flow flowing along the flexible connecting piece, reduce the influence on the air flow when the flexible connecting piece arches or wrinkles, and ensure the smoothness of the air flow channel. At the same time, the monitoring component can monitor the state of the air flow in real time, and can know in time when the air flow generates turbulence, so as to adjust the air flow and reduce the influence of the turbulence on the axial flow fan, and ensure the aerodynamic performance of the axial flow fan. Brief Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of the present invention;

[0019] Figure 2 is a schematic structural diagram when the sound insulation cavity and the cavity are not filled with sound insulation cotton;

[0020] Figure 3 is a schematic structural diagram when adjacent wedge plates are connected by a flexible cloth;

[0021] Figure 4 is a schematic diagram of the force decomposition of the air flow impact force on the wedge plate.

[0022] Reference numerals: 1 - housing, 2 - rubber layer, 3 - force measuring element, 4 - flexible expansion band, 5 - pressing 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 - bending edge, 15 - sound insulation cavity, 16 - cavity, 17 - flexible cloth. Detailed Description of the Invention

[0023] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0025] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "provided with", "installed", "connected", "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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] 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. The air inlet box includes a housing 1. The air inlet 8 of the housing 1 is connected to an external air duct through a flexible connector. Inside the flexible connector, a monitoring component is movably provided to block the contact between the air flow and the flexible connector and to monitor the air flow state in real time. The monitoring component is located on the air flow path.

[0027] In this embodiment, as Figure 1 shown, the air inlet box is directly connected to the air inlet end of the axial flow fan, ensuring the smooth entry of the air flow. This design enables the axial flow fan to operate efficiently while reducing the air flow loss caused by improper connection. The flexible connector can compensate for the displacement error during on-site installation. However, during use, the flexible connector may arch or wrinkle due to long-term expansion and contraction. The monitoring component on the air inlet path can block the contact path between the air flow and the flexible connector, preventing the air flow from flowing along the flexible connector, reducing the impact on the air flow when the flexible connector arches or wrinkles, and ensuring the smoothness of the air flow passage. At the same time, the monitoring component can monitor the air flow state in real time, promptly detect when the air flow becomes turbulent, so as to adjust the air flow and reduce the impact of the turbulence on the axial flow fan, ensuring the aerodynamic performance of the axial flow fan.

[0028] Furthermore, the monitoring component includes a wedge-shaped plate 11 and a force measuring element 3. The wedge-shaped plate 11 is movably arranged inside the air inlet 8 to block the contact between the air flow and the flexible connector. One side of the wedge-shaped plate 11 is an inclined straight surface, and the other side is a flat straight surface opposite to the inclined straight surface. The lower side of the flat straight surface is attached to the inner wall of the housing 1. The force measuring element 3 is arranged between the wedge-shaped plate 11 and the inner wall of the housing 1. The air flow acts on the inclined straight surface and squeezes the force measuring element 3 through the wedge-shaped plate 11.

[0029] Specifically, the wedge-shaped plate 11 is movably arranged inside the air inlet 8. The wedge-shaped plate 11 has a certain movement range both vertically and horizontally. Its main function is to block the direct contact between the air flow and the flexible connector, thereby reducing the impact on the air flow when the flexible connector arches or wrinkles and ensuring the smoothness of the air flow passage. One side of the wedge-shaped plate 11 is designed as an inclined straight surface, and the other side is a flat straight surface opposite to the inclined straight surface. When the air flow acts on the inclined straight surface, the direction of the air flow is vertical, as Figure 4As shown in the figure, the impact force generated will be decomposed into a lateral force on the inclined straight surface. The lateral force is horizontal and perpendicular to the housing 1. The lateral force pushes the wedge plate 11 towards the inner wall of the housing 1. When the force measuring element 3 senses this lateral force, it will generate a signal and output it to the controller. The controller measures and records the lateral force received by the wedge plate 11 in real time. By monitoring the magnitude and change of this lateral force, the state and intensity of the air flow can be indirectly understood. If the air flow is relatively smooth, then the change in the thrust monitored by the controller fluctuates less. At this time, the axial flow fan can continue to operate according to the current working conditions. If the change in the monitored lateral force fluctuates greatly and exceeds the threshold range, it can be determined at this time that the air flow has a turbulent phenomenon. Then it is necessary to timely adjust the operating state of the fan or stop the operation, or manually intervene in the air flow to avoid the occurrence of turbulent phenomena. The inclined straight surface of the wedge plate 11 is a smooth surface, which can reduce the occurrence of turbulent phenomena. At the same time, the lateral force can tightly press the wedge plate 11 against the inner wall of the housing 1, so that the wedge plate 11 is in close contact with the inner wall of the housing 1, better blocking the path of the air flow contacting the flexible connector. The lower side of the flat straight surface is attached to the inner wall of the housing 1. The widths of the wedge plate 11 and the inner wall of the housing 1 are basically the same. Multiple wedge plates 11 also form a funnel-shaped diversion structure, which can divert the gas to the intake end of the axial flow fan.

[0030] Working principle: When the air flow acts on the inclined straight surface of the wedge plate 11, the wedge plate 11 will receive 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 operating, the air flow enters from the air inlet 8. The impact force of the air flow acts on the inclined straight surface of the wedge plate 11. Due to the design of the inclined straight surface, the impact force of the air flow will generate a lateral thrust, pushing the wedge plate 11 towards the inner wall of the housing 1 to be pressed tightly. During this process, the force measuring element 3 will measure and record the magnitude of the lateral force received by the wedge plate 11. By monitoring the magnitude and change of this lateral force, the state and intensity of the air flow can be indirectly understood, including the flow rate, flow volume of the air flow and whether there are abnormal fluctuations, etc.

[0031] Real-time monitoring: Through the real-time monitoring function of the force measuring element 3, abnormal changes in the air flow state can be discovered in time, providing strong data support for the operation and maintenance of the fan.

[0032] Improve the performance of the fan: By monitoring the air flow state, the operating parameters of the fan can be adjusted in time to ensure that it always operates in the best state, thereby improving the overall performance of the fan.

[0033] Further, the air inlet 8 is rectangular. A bent edge 14 integrally formed with the housing 1 is provided circumferentially around the air inlet 8. The bent edge 14 is located outside the housing 1. The lower end of the flexible connecting member is connected to the side surface of the bent edge 14. Above the bent edge 14, there is a fixing plate 6 connected to an external pipeline. The fixing plate 6 is L-shaped. The upper end of the flexible connecting member is connected to the side surface of the fixing plate 6. The top end of the wedge-shaped plate 11 is movably connected to a mounting plate 12, and the mounting plate 12 is connected to the bottom surface of the fixing plate 6.

[0034] Specifically, the air inlet 8 is designed to be rectangular. This shape is beneficial for the uniform distribution of air flow and the reduction of the formation of eddy currents, thereby improving the efficiency of the fan. As Figure 1 shown, a bent edge 14 integrally formed with the housing 1 is provided circumferentially around the air inlet 8. This design not only enhances the structural strength of the air inlet 8 but also provides a stable interface for connecting with the flexible connecting member. The bent edge 14 is L-shaped. The lower end of the flexible connecting member is connected to the side surface of the bent edge 14. Above the bent edge 14, there is a fixing plate 6 connected to an external pipeline. The fixing plate 6 is L-shaped. The top end of the wedge-shaped plate 11 is movably connected to a mounting plate 12. This design enables the wedge-shaped plate 11 to have a certain displacement ability. It can move vertically following the expansion and contraction of the flexible connecting member and can also move towards the inner wall direction of the housing 1 under the action of a lateral force. At the same time, the mounting plate 12 provides stable support for the wedge-shaped 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.

[0035] When the air flow passes through the air inlet 8, it acts on the inclined straight surface of the wedge-shaped plate 11, pushing the wedge-shaped plate 11 to move, and the force change during this process is recorded by the force measuring element 3. This design allows for the real-time monitoring of the air flow state, including key parameters such as flow velocity and flow rate, to promptly detect air flow turbulence phenomena.

[0036] Further, 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.

[0037] Specifically, the resistance strain type pressure sensor has a relatively thin thickness and a small volume, and can be arranged in the inner wall of the housing 1 by embedding. The pressure sensing end of the resistance strain type pressure sensor faces the flat surface of the wedge-shaped plate 11. In this way, when the wedge-shaped plate 11 receives a lateral thrust from the air flow, it can squeeze the resistance strain type pressure sensor with the inner wall of the housing 1. At the same time, in order to avoid air flow leakage at the installation gap, sealant is applied circumferentially around the resistance strain type pressure sensor.

[0038] Further, the wedge-shaped plates 11 are distributed around the air inlet 8. Adjacent wedge-shaped plates 11 are connected by a flexible cloth 17. The flexible cloth 17 is a flexible fiberglass cloth, and sealant is coated on the flexible cloth 17.

[0039] Specifically, the wedge plates 11 are distributed around the air inlet 8. Such a layout ensures that the airflows 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 connecting member, and the air flow state is monitored in real time through the force measuring element 3. This distribution method not only improves the accuracy and comprehensiveness of the monitoring, but also enhances the structural strength of the air intake box, as Figure 3 shown, the adjacent two wedge plates 11 are connected by a flexible fiberglass cloth. The flexible fiberglass 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 the air flow without being restricted by the connecting member. Coating a sealant on the flexible fiberglass cloth can further enhance the sealing performance of the connection. The sealant can fill the tiny gaps at the connection and prevent air leakage, thereby improving the sealing performance and efficiency of the air intake box.

[0040] Comprehensive monitoring: Through the distribution of the wedge plates 11 around the air inlet 8, the comprehensive monitoring of the air flow state is realized, and the accuracy and reliability of the monitoring are improved.

[0041] Enhanced sealing: The combined use of the flexible fiberglass cloth and the sealant ensures the sealing performance of the connection of the air intake box, reducing air leakage and energy loss.

[0042] Improved flexibility: The flexibility of the flexible fiberglass cloth enables the wedge plate 11 to move freely under the action of the air flow, improving the flexibility and adaptability of the air intake box.

[0043] Enhanced structural strength: Through the distribution and connection of the wedge plates 11 and the flexible fiberglass cloth, the overall structural strength of the air intake box is enhanced, and it can withstand greater air flow pressure and external loads.

[0044] Furthermore, the upper part inside the wedge plate 11 has a cavity 16, and the lower part is a solid structure. The center of gravity of the wedge plate 11 is located at its lower end.

[0045] Furthermore, the cavity 16 is filled with sound-absorbing cotton 13.

[0046] Specifically, as Figure 2As shown, the upper part of the wedge-shaped plate 11 has a cavity 16 inside. This design effectively reduces the weight of the wedge-shaped plate 11, and the cavity 16 also provides space for filling the sound insulation cotton 13. The lower part of the wedge-shaped plate 11 is a solid structure, so that the center of gravity of the wedge-shaped plate 11 is located at its lower end. Such a layout makes the wedge-shaped plate 11 easier to maintain balance and stability when affected by air flow, reducing the noise and wear generated by shaking, and also making the wedge block better fit on the inner wall of the housing 1. Filling the sound insulation cotton 13 in the cavity 16 of the wedge-shaped plate 11 can significantly improve the sound insulation effect of the air inlet box. The sound insulation cotton 13 can absorb and reflect the noise generated by the air flow, reduce the interference of the noise on the surrounding environment, and improve the overall performance of the fan. The sound insulation cotton 13 also has a certain heat preservation performance, which can reduce the temperature loss of the air flow when passing through the air inlet box and improve the energy efficiency of the fan.

[0047] Furthermore, a sound insulation cavity 15 is formed among the flexible connecting piece, the upper part of the wedge-shaped plate 11, the top of the bent edge 14, and the mounting plate 12, and sound insulation materials are filled in the sound insulation cavity 15.

[0048] Specifically, as Figure 2 shown, the sound insulation cavity 15 is jointly formed by the flexible connecting piece, the wedge-shaped plate 11, the top of the bent edge 14, and the mounting plate 12. The tight fit among these components ensures the sealing performance of the sound insulation cavity 15 and prevents the leakage of noise. Sound insulation materials are filled in the sound insulation cavity 15, and the sound insulation materials can be fixed in the sound insulation cavity 15 by bonding. The sound insulation materials can be sound insulation cotton 13, sound insulation foam, etc. These materials have excellent sound absorption and sound insulation performance and can effectively absorb and reflect noise, reducing its propagation distance and intensity.

[0049] The combined use of the sound insulation cavity 15 and the sound insulation materials significantly improves the sound insulation effect of the air inlet box. This design can effectively reduce the interference of the noise generated during the operation of the fan on the surrounding environment and improve the overall acoustic performance.

[0050] Furthermore, the flexible connecting piece is a flexible expansion band 4. The upper end of the flexible expansion band 4 is installed on the side surface of the fixed plate 6 through a pressing plate 5, and the lower end of the flexible expansion band 4 is installed on the side surface of the bent edge 14 through a pressing plate 5. The pressing plate 5 is fixed to the mounting plate 12 and the bent edge 14 by bolts.

[0051] Furthermore, the side surface of the wedge-shaped 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-shaped plate 11 and the mounting plate 12 are connected by an arc-shaped rubber plate 7.

[0052] Specifically, the side of the wedge plate 11 in contact with the inner wall of the housing 1 is coated with a rubber layer 2. This design significantly enhances the sealing performance between the two. The rubber layer 2 can fill the tiny gaps between the wedge plate 11 and the inner wall of the housing 1, prevent air leakage, ensure the sealing performance of the air intake box. The rubber layer 2 also has certain elasticity and lubricity, which can reduce the friction and wear between the wedge plate 11 and the inner wall of the housing 1 during movement, and extend the service life of the air intake box.

[0053] To further prevent gas from escaping into the sound insulation cavity 15, an arc-shaped rubber film 10 is provided at the bottom of the wedge plate 11. The rubber film 10 fits on the inner wall of the housing 1. Under the action of the internal air pressure in the housing 1, the rubber film 10 is pressed tightly against the inner wall of the housing 1, thereby further blocking the path between the air flow and the sound insulation cavity 15. The upper end of the rubber film 10 is large and the lower end is small, and the outer surface is an arc surface. The connection with the wedge plate 11 is an arc-shaped transition surface 9, so that the fluidity of the air flow is better. The surrounding wedge plates 11 and the rubber film 10 form a variable flow channel. The wedge plates 11 and the rubber film 10 with a certain length can provide a buffer zone for the fluid to enter or exit, which helps the air flow to transition smoothly, reduces the changes in pressure and speed, and reduces the probability of turbulence occurrence.

[0054] As Figure 2 shown, the upper end of the wedge plate 11 is connected to the mounting plate 12 through an arc-shaped rubber plate 7. This design increases the flexibility of the connection. The arc-shaped rubber plate 7 can adapt to the tiny displacement of the wedge plate 11 under the action of the air flow, 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.

[0055] 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 air leakage, and improve energy efficiency.

[0056] 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, ensuring the reliability of the air intake box during long-term operation.

[0057] Noise and vibration reduction: The elastic properties of the rubber layer 2 and the arc-shaped rubber plate 7 help reduce the transmission of vibration and noise, improving the acoustic performance of the air intake box.

[0058] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Based on the technical essence of the present invention, any simple modifications, equivalent replacements, and improvements made to the above embodiments within the spirit and principles of the present invention still fall 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) is connected to an external air duct via a flexible connector, a monitoring component is movably provided inside the flexible connector to block the airflow from contacting the flexible connector and monitor the airflow state in real time, and the monitoring component is located on the airflow path; 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).

2. An axial flow fan with an air inlet box according to claim 1, 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).

3. The axial flow fan with an air inlet box according to claim 1, 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).

4. The axial flow fan with an air inlet box according to claim 1, 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.

5. The axial flow fan with an air inlet box according to claim 1, 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.

6. The axial flow fan with an air inlet box according to claim 5, characterized in that: The cavity (16) is filled with sound insulation cotton (13).

7. The axial flow fan with an air inlet box according to claim 2, 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.

8. 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.

9. The axial flow fan with an air inlet box according to claim 1, 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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