An industrial centrifugal fan with a forced flow guiding inner cavity structure

Abstract

The present invention discloses an industrial centrifugal fan with a forced flow-guiding inner cavity structure, relates to the technical field of centrifugal fans, and is used to solve the problem in the prior art that the impeller in the centrifugal fan cannot be automatically cleaned, resulting in reduced performance of the centrifugal fan; the present invention uses a cleaning tank on a transmission housing to regularly introduce cleaning liquid into the end of the rotating shaft, and moves the cleaning liquid from the drainage hole to discharge into the impeller surface, and with the impeller rotating in the reverse direction at a low speed, the cleaning liquid continuously impacts the impeller surface, thereby completing automatic flushing of the impeller, and preventing the wet impeller from being secondary polluted by impurities in the air during rotation, utilizing the rotation of the rotating shaft to drive the rotation of the sleeve, and completing the closing of the guide blades at the front end of the casing, thereby preventing the influx of airflow caused by the rotation of the impeller, and subsequently automatically drying the impeller by rotating at a high speed, thereby realizing automatic cleaning of the impeller when the centrifugal fan is working.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fans, in particular to an industrial centrifugal fan with a forced flow guide inner cavity structure. Background Art

[0002] A centrifugal fan is a driven fluid machine that relies on input mechanical energy to increase gas pressure and discharge the gas. Centrifugal fans are widely used for ventilation, dust removal, and cooling in factories, mines, tunnels, cooling towers, vehicles, ships, and buildings. In a single-stage centrifugal fan, gas enters the impeller axially, changes direction as it passes through the impeller, and then enters the diffuser. In the diffuser, the gas changes direction and slows down. This deceleration converts kinetic energy into pressure energy. The pressure increase occurs primarily in the impeller, and secondarily in the expansion process. In a multi-stage centrifugal fan, a recirculator is used to direct the airflow into the next impeller, generating higher pressure.

[0003] Controlling the air volume of a centrifugal fan can not only maximize the effect of the centrifugal fan, but also help users reduce energy consumption. There are several ways to adjust the air volume of a centrifugal fan, such as adjusting the size of the opening valves of the air inlet and outlet, adjusting the volute line shape, adjusting the size of the impeller blades, adjusting the impeller angle, adjusting the belt drive speed, or adjusting the power pole number of the drive motor, etc. By adjusting the flow rate by adjusting the opening and closing degree of the door, the direction of the air flow entering the casing can be forced to change, and as the impeller rotates, the gas can be discharged from the casing more quickly. At the same time, due to the different working environments of centrifugal fans, the impeller needs to be shut down for cleaning after long-term operation. Common disassembly and wiping cleaning will be limited by the installation location and number of centrifugal fans. Therefore, there is an urgent need for industrial centrifugal fans with automatic impeller cleaning.

[0004] To this end, we propose an industrial centrifugal fan with a forced flow guide inner cavity structure. Summary of the Invention

[0005] The object of the present invention is to provide an industrial centrifugal fan with a forced flow guide inner cavity structure to solve the problem of poor performance of centrifugal fans caused by the inability to adjust the air volume on the air inlet side and the inability to automatically clean the impeller inside the centrifugal fan proposed in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An industrial centrifugal fan with a forced flow guide inner cavity structure comprises a base, a transmission housing is fixed to the top of the base by bolts, one side of the transmission housing is fixedly connected to the housing by spot welding, and an air outlet is opened on the top of the housing;

[0008] The top of the base is fixed with a motor 1 by bolts, the output end of the motor 1 is fixed with a pulley 1, a rotating sleeve is movably connected in the transmission housing, an impeller is movably connected in the housing, one side of the rotating sleeve is fixed to the impeller by bolts, the rotating sleeve is located in the transmission housing and is fixed with a pulley 2, and a belt is installed on the pulley 2 on the rotating sleeve and the pulley on the motor 1;

[0009] A trigger mechanism is installed in the transmission housing, and the trigger mechanism includes a rotating shaft, a water pipe and a drainage hole. A rotating shaft is slidably connected in the transmission housing and located in the rotating sleeve. The rotating shaft is hollow and one end is movably connected to the water pipe. One end of the rotating shaft passes through the rotating sleeve and is fixed to the inner wall of the wind collecting cover by bolts. The outer wall of the rotating shaft on the impeller side is evenly provided with drainage holes.

[0010] The trigger mechanism further includes a baffle and a spring. The outer wall of the rotating shaft is sleeved with a baffle movably connected thereto, and one side of the bottom of the baffle is slidably engaged with the inner wall of the transmission housing. The outer wall of the rotating shaft is sleeved with a spring, and one side of the spring is in contact with the transmission housing.

[0011] The top of the transmission housing is fixed with a second motor by bolts, the output end of the second motor passes through the transmission housing and is sleeved and fixed with a first transmission gear, the outer wall of the rotating shaft is sleeved with a gear sleeve in sliding connection, and one side of the gear sleeve is meshed with the first transmission gear, and the other side of the gear sleeve is fixed with a protrusion by spot welding, and one side of the protrusion is in contact with a blocking piece;

[0012] The outer wall of the rotating shaft is located in the casing and is slidably connected to a sleeve. The outer surface of the sleeve is evenly and movably connected to a guide fan blade. One side of the guide fan blade passes through the through hole on the wind collecting cover and extends into the casing. The end of the guide fan blade is located in the casing and is fixed with a transmission tooth 2. The inner wall of the casing is fixed with a gear ring by bolts, and the gear ring is meshed with the transmission tooth 2.

[0013] Furthermore, an air collecting hood is slidably mounted inside the casing, and the air collecting hood is located on an outer side wall of the casing and is evenly provided with liquid leakage holes.

[0014] Furthermore, a cleaning tank is fixed to one side of the transmission housing by bolts, one end of the water pipe passes through the transmission housing and is connected to the cleaning tank, and a solenoid valve is installed on the outside of the water pipe.

[0015] The working method of the industrial centrifugal fan with a forced flow guide cavity structure is as follows:

[0016] According to the working environment of the centrifugal fan, before starting, the second motor drives the transmission gear in the transmission housing to rotate 30 degrees counterclockwise, so that the gear sleeve drives the rotating shaft to rotate, and the sleeve on the rotating shaft drives the guide blades and the transmission gear at the end of the guide blades to rotate in the housing. The transmission gear contacts the gear ring on the inner wall of the housing to drive the guide blades to unfold. The maximum opening and closing angle of the guide blades is controlled at 45 degrees. At this time, the first motor on the base is started again, and the pulley on the first motor drives the pulley on the rotating sleeve in the transmission housing to rotate. The impeller at the end of the rotating sleeve starts to rotate at high speed, continuously discharging air from the air outlet.

[0017] To control the exhaust volume, the second motor rotates in the opposite direction to drive the shaft to reset, and the sleeve on the shaft and the guide blades on the sleeve rotate in the opposite direction, the opening and closing angle between the guide blades decreases, the air intake decreases, and the exhaust volume of the centrifugal fan decreases.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. In the present invention, the rotation angle of the rotating shaft in the housing is adjusted by rotating the second motor on the transmission housing. Furthermore, through the sleeve mounted on the rotating shaft and the guide blades movably connected to the sleeve surface, when the rotating shaft rotates, the second transmission tooth at the end of the guide blade contacts the ring gear on the inner wall of the housing and automatically rotates, thereby controlling the deflection angle of the guide blades. This, in turn, controls the direction of the airflow drawn into the housing when the impeller rotates, thereby increasing the gas discharge rate.

[0020] 2. In the present invention, cleaning liquid is regularly introduced into the end of the rotating shaft through the cleaning tank on the transmission housing, and the cleaning liquid is moved and discharged into the surface of the impeller from the drainage hole. As the impeller rotates in the opposite direction at a low speed, the cleaning liquid continuously impacts the surface of the impeller, thereby completing the automatic flushing of the impeller and preventing the secondary contamination of the wet impeller by impurities in the air during the rotation process. The rotation of the rotating shaft drives the rotation of the sleeve, and the guide blades are closed at the front end of the casing to prevent the influx of air caused by the rotation of the impeller. Subsequently, the impeller is automatically dried by rotating at a high speed, thereby realizing automatic cleaning of the impeller when the centrifugal fan is working, without the need to disassemble the fan, and improving the working efficiency of the centrifugal fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of an industrial centrifugal fan with a forced flow guide inner cavity structure according to the present invention;

[0022] Figure 2 This is a schematic diagram of the internal transmission structure of an industrial centrifugal fan with a forced flow guide inner cavity structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the impeller installation structure in the casing of the present invention;

[0024] Figure 4This is a schematic diagram of the structure of the air collecting cover extending outward from the casing of the present invention;

[0025] Figure 5 This is a schematic diagram of the second connection structure of the transmission gear at the end of the guide blade of the present invention;

[0026] Figure 6 This is a schematic diagram of the transmission structure of an industrial centrifugal fan with a forced flow guide inner cavity structure according to the present invention.

[0027] In the figure: 1. base; 2. transmission housing; 3. motor 1; 4. motor 2; 5. housing; 6. air collecting hood; 7. cleaning tank; 8. rotating sleeve; 9. impeller; 10. trigger mechanism; 101. rotating shaft; 102. baffle; 103. water pipe; 104. spring; 105. drain hole; 11. gear sleeve; 12. transmission gear 1; 13. leakage hole; 14. sleeve; 15. guide blade; 16. transmission gear 2; 17. gear ring; 18. air outlet; 19. pulley 1; 20. pulley 2; 21. boss. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1-6 , the present invention provides a technical solution:

[0030] Example 1: In a single-stage centrifugal fan, gas enters the impeller 9 from the axial direction, changes to radial direction when flowing through the impeller 9, and then enters the diffuser. In the diffuser, the gas changes its flow direction and causes deceleration. This deceleration converts kinetic energy into pressure energy. The pressure increase mainly occurs in the impeller 9, and secondly occurs in the diffusion process. The air volume of a newly installed centrifugal fan will be too large. Usually, the flow rate is adjusted by changing the speed of the fan or by adjusting the opening and closing degree of the door. The present invention is located at the front end of the centrifugal fan. The casing 5 is installed with a trigger mechanism 10, and multiple groups of guide blades 15 are installed on the trigger mechanism 10. The rotation of the rotating shaft 101 is used to realize the offset angle control of the guide blades 15, thereby forcibly changing the direction of the airflow after the impeller 9 rotates, thereby accelerating the gas to be discharged from the air outlet 18, and also facilitating the flow adjustment of the centrifugal fan.

[0031] Different from the conventional outer shell design, the upper shaft 101 of the trigger mechanism 10 is located in the transmission shell 2 behind the impeller 9, which can be adjusted more centrally without affecting the normal rotation of the impeller 9. Figure 2As shown, the centrifugal fan adopts a belt drive mode, a pulley 19 is fixed on the output end of the motor 3 installed on the base 1, and a pulley 20 is fixed on the rotating sleeve 8 in the transmission housing 2. Figure 3 It can be understood that one end of the rotating sleeve 8 is located in the casing 5 and is fixed to the impeller 9 by bolts, so the rotation of the motor 1 3 directly drives the impeller 9 to rotate;

[0032] Taking into account the placement angle control of the front guide blade 15, a rotating shaft 101 is slidably connected to the rotating sleeve 8 in the transmission housing 2. The rotating shaft 101 is hollow, wherein a gear sleeve 11 is slidably connected on the rotating shaft 101 and located in the transmission housing 2, and a motor 2 4 is fixed on the top of the transmission housing 2. The motor 2 4 is located in the transmission housing 2 and is fixed with a transmission gear 12. The transmission gear 12 is meshed with the gear sleeve 11. The rotating shaft 101 is controlled by the motor 2 4 to rotate in the transmission housing 2. Figure 3 As shown, the front end of the rotating shaft 101 is connected to the wind collecting cover 6 sliding in the housing 5, and a sleeve 14 is slidably connected to the rotating shaft 101, and the sleeve 14 is evenly and movably connected to the guide blade 15. The end of the middle axis of the guide blade 15 passes through the through hole on the wind collecting cover 6 and extends into the housing 5. At the same time, the housing 5 is used to limit the transmission tooth 2 16 fixed to the end of the middle axis of the guide blade 15, so as to prevent the subsequent left and right movement of the rotating shaft 101 from causing the guide blade 15 to slide, thereby affecting the airflow control of the guide blade 15;

[0033] like Figure 5 As shown, a gear ring 17 is fixed to the inner wall of the housing 5 by bolts. The gear ring 17 engages and abuts with the second transmission tooth 16 on the guide blade 15. Therefore, when the rotating shaft 101 rotates a certain angle, the second transmission tooth 16 contacts the gear ring 17, thereby driving the guide blade 15 to rotate, thereby realizing the rotation and opening and closing of the combined guide blade 15.

[0034] like Figure 2As shown, a baffle 102 is also sleeved on the rotating shaft 101 and is slidably connected. The baffle 102 is provided with a side convexity, and a boss 21 is fixed to the back side of the gear sleeve 11 by spot welding. When the gear sleeve 11 rotates counterclockwise, the boss 21 on the gear sleeve 11 does not contact the side convexity on the baffle 102, so it will not drive the rotating shaft 101 to move. The bottom of the baffle 102 is engaged with the inner wall of the transmission case 2, so it can only slide back and forth on the rotating shaft 101. When the gear sleeve 11 rotates clockwise, the boss 21 at this time contacts the side convexity on the baffle 102, and the gear sleeve 11 itself is on the rotating shaft. 101 is abutted by the transmission tooth 12, and its position does not change, but the baffle 102 will push the shaft 101 to the left to slide, thereby driving the entire shaft 101 to move. For the reset movement of the shaft 101, every time the shaft 101 moves, it will squeeze the sleeve spring 104, so the shaft 101 is pushed to reset by the spring 104. Therefore, when performing conventional steering control of the guide fan blade 15, only the fixed rotation of the shaft 101 is considered. At the same time, the rotation opening direction of the guide fan blade 15 can be known according to the position of the air outlet 18 on the casing 5.

[0035] Example 2: Considering the working environment of a centrifugal fan, dust and impurities are more or less adsorbed on its impeller 9. Common cleaning methods for centrifugal fans include disassembly and cleaning, and drying and reassembly. However, centrifugal fans in harsh environments, such as mine ventilation, are more difficult to clean due to the number of centrifugal fans installed and the disassembly process. Therefore, the centrifugal fan of the present invention can be automatically cleaned at regular intervals.

[0036] A cleaning tank 7 is installed on the outside of the transmission housing 2. Cleaning liquid is stored in the cleaning tank 7. When the centrifugal fan impeller 9 needs to be cleaned, the cleaning liquid in the cleaning tank 7 will enter the cavity of the rotating shaft 101 due to the opening of the solenoid valve on the water pipe 103. As the cleaning liquid flows, it finally reaches the surface of the impeller 9 along the drainage hole 105 on the rotating shaft 101. After the low-speed rotation of the rotating sleeve 8, the cleaning liquid continuously contacts the impeller 9. The rotation of the impeller 9 flushes the impeller 9, so that the dust adsorbed on its surface is dissolved in the cleaning liquid.

[0037] To prevent the cleaning liquid from flowing out of the casing 5 at a faster rate and the wet impeller 9 from being contaminated by dust in the incoming air, the guide blades 15 on the sleeve 14 need to be closed to prevent the airflow from entering completely. At this time, the motor 2 4 drives the transmission gear 12 to rotate counterclockwise, and the rotation of the gear sleeve 11 causes the boss 21 to contact the upper convex side of the baffle 102, thereby promoting the movement of the rotating shaft 101 during the rotation process. The wind collecting cover 6 connected to the front end of the rotating shaft 101 is also shown. Figure 4 As shown, the leftward movement causes the leakage hole 13 on the wind collecting cover 6 to open, at which time the guide blades 15 are closed, and the impeller 9 automatically completes the cleaning process during the low-speed rotation, and then the sewage is discharged from the leakage hole 13;

[0038] Considering that the impeller 9 needs to be kept dry after cleaning, after the cleaning tank 7 stops draining, the clean sewage automatically flows out, and the impeller 9 is idling while the guide blades 15 are continuously closed. The high-speed reverse rotation of the impeller 9 generates a centrifugal force to continuously move the accumulated liquid toward the front guide blades 15. Then, the impeller 9 is dried, and the reverse rotation of the rotating shaft 101 is used to close the leakage hole 13 on the wind collecting cover 6 and open the guide blades 15 on the rotating shaft 101, thereby starting the normal operation of the centrifugal fan.

[0039] By setting up an automatic cleaning mechanism for the impeller 9 and cooperating with the closed environment formed by the guide blades 15 and the casing 5, the impeller 9 can be automatically cleaned during the continuous flushing process and will not be secondary polluted by dust in the air. At the same time, the automatic discharge of clean sewage and the reverse rotation and drying of the impeller 9 prevent sewage from entering the external connecting pipe through the air outlet 18, ensuring the subsequent efficient operation of the centrifugal fan.

[0040] Working principle of the present invention:

[0041] According to the working environment of the centrifugal fan, before starting, the motor 2 4 drives the transmission gear 12 in the transmission housing 2 to rotate counterclockwise by 30 degrees, so that the gear sleeve 11 drives the rotating shaft 101 to rotate, and the sleeve 14 on the rotating shaft 101 drives the guide blades 15 and the transmission gear 2 16 at the end of the guide blades 15 to rotate in the casing 5. The transmission gear 2 16 contacts the gear ring 17 on the inner wall of the casing 5 to drive the guide blades 15 to unfold. The maximum opening and closing angle of the guide blades 15 is controlled at 45 degrees at this time. At this time, the motor 1 3 on the base 1 is started again, and the pulley 19 on the motor 1 3 drives the pulley 2 20 on the rotating sleeve 8 in the transmission housing 2 to rotate. The impeller 9 at the end of the rotating sleeve 8 starts to rotate at high speed, continuously discharging air from the air outlet 18;

[0042] To control the exhaust volume, the motor 2 (4) rotates in the reverse direction to drive the shaft 101 to reset, and the sleeve 14 on the shaft 101 and the guide blades 15 on the sleeve 14 rotate in the opposite direction. The opening and closing angle between the guide blades 15 decreases, the air intake decreases, and the exhaust volume of the centrifugal fan decreases.

[0043] When the motor 2 4 continues to rotate in the reverse direction, the boss 21 on the gear sleeve 11 contacts the baffle 102 on the shaft 101, pushing the shaft 101 against which the baffle 102 abuts to slide, thereby causing the guide blades 15 on the sleeve 14 to fully close, and the air intake of the entire centrifugal fan is blocked.

[0044] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0045] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0046] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An industrial centrifugal fan with a forced flow guide inner cavity structure, comprising a base (1) and a trigger mechanism (10), characterized in that: A transmission housing (2) is fixed to the top of the machine base (1) by bolts, one side of the transmission housing (2) is fixedly connected to the machine housing (5) by spot welding, and an air outlet (18) is provided on the top of the machine housing (5); The top of the machine base (1) is fixed with a motor (3) by bolts, and a pulley (19) is fixedly mounted on the output end of the motor (3), a rotating sleeve (8) is movably connected in the transmission housing (2), and an impeller (9) is movably connected in the housing (5), and one side of the rotating sleeve (8) is fixed to the impeller (9) by bolts, and the rotating sleeve (8) is located in the transmission housing (2) and is fixedly mounted with a pulley (20), and a belt is mounted on the pulley (20) on the rotating sleeve (8) and the pulley (19) on the motor (3); The trigger mechanism (10) comprises a rotating shaft (101), a water pipe (103) and a drainage hole (105); the rotating shaft (101) is slidably connected in the rotating sleeve (8) in the transmission housing (2); the rotating shaft (101) is hollow and one end of the rotating shaft (101) is movably connected to the water pipe (103); the other end of the rotating shaft (101) passes through the rotating sleeve (8) and is fixed to the inner wall of the wind collecting cover (6) by bolts; the outer wall of the rotating shaft (101) located on the side of the impeller (9) is evenly provided with drainage holes (105); The trigger mechanism (10) further comprises a baffle (102) and a spring (104); the baffle (102) is sleeved on the outer wall of the rotating shaft (101) and movably connected thereto, and one side of the bottom of the baffle (102) is slidably engaged with the inner wall of the transmission housing (2); the spring (104) is sleeved on the outer wall of the rotating shaft (101), and one side of the spring (104) is in contact with the transmission housing (2); The top of the transmission housing (2) is fixed with a second motor (4) by bolts, the output end of the second motor (4) passes through the transmission housing (2) and is sleeved and fixed with a transmission tooth (12), the outer wall of the rotating shaft (101) is sleeved with a gear sleeve (11) in sliding connection, and one side of the gear sleeve (11) is meshed with the transmission tooth (12), and the other side of the gear sleeve (11) is fixed with a protrusion (21) by spot welding, and one side of the protrusion (21) is in contact with the baffle (102); The outer wall of the rotating shaft (101) is sleeved and slidably connected with a sleeve (14) located in the housing (5). The rotating shaft (101) can drive the sleeve (14) to rotate. The outer surface of the sleeve (14) is evenly and movably connected with a guide blade (15). One side of the guide blade (15) passes through the through hole on the wind collecting cover (6) and extends into the housing (5). The end of the guide blade (15) is sleeved and fixed with a transmission tooth 2 (16) located in the housing (5). A gear ring (17) is fixed to the inner wall of the housing (5) by bolts, and the gear ring (17) is meshed with the transmission tooth 2 (16); The baffle (102) is provided with a side convexity. When the gear sleeve (11) rotates so that the boss (21) contacts the side convexity on the baffle (102), the position of the gear sleeve (11) itself on the rotating shaft (101) does not change. At this time, the baffle (102) pushes the rotating shaft (101) to slide to the left, thereby driving the entire rotating shaft (101) to move.

2. The industrial centrifugal fan with a forced flow guide inner cavity structure according to claim 1, characterized in that: An air collecting hood (6) is slidably mounted inside the casing (5), and the air collecting hood (6) is located on an outer side wall of the casing (5) and is evenly provided with liquid leakage holes (13).

3. The industrial centrifugal fan with a forced flow guide inner cavity structure according to claim 2, characterized in that: A cleaning tank (7) is fixed to one side of the transmission housing (2) via bolts, one end of the water pipe (103) passes through the transmission housing (2) and is connected to the cleaning tank (7), and a solenoid valve is installed on the outside of the water pipe (103).

4. The industrial centrifugal fan with a forced flow guide inner cavity structure according to claim 3, characterized in that: The working method of the industrial centrifugal fan with a forced flow guide cavity structure is as follows: According to the working environment of the centrifugal fan, before starting, the motor 2 (4) drives the transmission gear 1 (12) in the transmission housing (2) to rotate 30° counterclockwise, so that the gear sleeve (11) drives the rotating shaft (101) to rotate, and the sleeve (14) on the rotating shaft (101) drives the guide blade (15) and the transmission gear 2 (16) at the end of the guide blade (15) to rotate in the housing (5). The transmission gear 2 (16) contacts the gear ring (17) on the inner wall of the housing (5) to drive the guide blade (15) to unfold. The maximum opening and closing angle of the guide blade (15) is controlled at 45°. At this time, the motor 1 (3) on the base (1) is started again, and the pulley 1 (19) on the motor 1 (3) drives the pulley 2 (20) on the rotating sleeve (8) in the transmission housing (2) to rotate. The impeller (9) at the end of the rotating sleeve (8) starts to rotate at high speed, and continuously discharges the airflow from the air outlet (18); To control the exhaust volume, the motor 2 (4) rotates in the reverse direction to drive the shaft (101) to reset, and the sleeve (14) on the shaft (101) and the guide blades (15) on the sleeve (14) rotate in the reverse direction, the opening and closing angle between the guide blades (15) decreases, the air intake decreases, and the exhaust volume of the centrifugal fan decreases.

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