Multi-bladed low-noise centrifugal fan

Abstract

The application belongs to the technical field of centrifugal ventilators, and discloses a multi-wing low-noise centrifugal ventilator, which comprises a supporting table and a volute shell mounted on the side of the supporting table. The volute shell is connected with an air inlet cover at the left end, and is connected with an air outlet pipe at the upper end. A transmission shaft is penetrated through the right side of the volute shell, and the left end of the transmission shaft is connected with a positioning disc. The outer edge of the positioning disc is connected with a blade. The right end of the transmission shaft is connected with a transmission assembly, which drives the rotation of the transmission shaft to provide power for the ventilator. A flushing assembly is mounted on the side of the supporting table. The multi-wing low-noise centrifugal ventilator can effectively regulate the air flow through the guide plates arranged in an array on the inner wall of the air outlet pipe, eliminate the airflow turbulence and vortex phenomenon, reduce the air supply resistance, and significantly improve the air supply efficiency and air outlet uniformity of the ventilator. Meanwhile, the sound-absorbing pads arranged on the inner wall of the volute shell can absorb the airflow noise and mechanical vibration noise from the sound source, weaken the noise propagation, and realize the low-noise and high-stability operation of the equipment in all directions.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, specifically to a multi-blade low-noise centrifugal fan. Background Technology

[0002] Centrifugal fans mainly consist of: impeller, casing, coupling, and shaft. The impeller is the main working component that generates air pressure and transmits energy. The casing is mainly used to introduce and discharge gas, while converting some of the gas's kinetic energy into pressure energy. The coupling is used to connect the motor and the fan, transmitting torque. The shaft mounts and fixes the impeller and connects to the motor via the coupling. When the impeller rotates, the gas between the blades of the centrifugal fan gains kinetic energy (dynamic pressure head) under the action of centrifugal force and is discharged from the periphery of the impeller. Guided by the volute-shaped casing, it flows towards the fan outlet, thereby creating a negative pressure in the center of the impeller, allowing external airflow to continuously flow in and replenish it, thus enabling the fan to discharge gas.

[0003] However, existing multi-blade low-noise centrifugal fans still have some problems in use: An adjustable centrifugal fan, as described in Chinese patent application number CN202223261178.0, includes: a centrifugal fan body; a centrifugal fan support is provided on one side of the centrifugal fan body; an adjustment mechanism is provided at one end of the lower part of the centrifugal fan support; an automatic cylinder is provided on one side of the adjustment mechanism; a lifting and retracting column is provided on one side of the cylinder; and a connecting block is provided on one side of the lifting and retracting column. This adjustable centrifugal fan effectively prevents dust from entering and causing machine malfunctions when the exhaust and outlet dust covers are closed, and can be easily removed when in use, making installation and disassembly convenient.

[0004] Although existing fan equipment has been equipped with dustproof structures, it cannot completely prevent dust from entering the fan. If dust accumulates on the impeller after long-term use, it will aggravate the vibration and resistance during high-speed rotation, increase noise and energy consumption. Moreover, cleaning the dust is cumbersome and requires stopping the machine and disassembling the impeller.

[0005] To address the aforementioned issues, an innovative design was developed based on the existing multi-blade low-noise centrifugal fan. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-blade low-noise centrifugal fan to solve the problem mentioned in the background art that when existing fan impellers accumulate dust, the entire equipment needs to be shut down and the internal impeller and other related structures need to be disassembled and cleaned, which is a cumbersome operation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a multi-blade low-noise centrifugal fan, comprising a support platform and a volute mounted on its side: The left end of the volute is connected to an air inlet shroud, the upper end of the volute is connected to an air outlet pipe, the right side of the volute is connected to a drive shaft, the left end of the drive shaft is connected to a positioning plate, the outer edge of the positioning plate is connected to a blade, and the right end of the drive shaft is connected to a drive assembly, which drives the drive shaft to rotate to provide power to the fan. A flushing assembly is installed on the side of the support platform. The flushing assembly includes a water pump and a nozzle. The nozzle is connected to the side wall of the volute and is connected to the water pump. The outer wall of the blade is connected to a limiting disk, which is rotatably connected to the positioning disk. A transmission gear is connected to the right side of the limiting disk, and a transmission gear is rotatably mounted on the right side of the positioning disk. The outer wall of the transmission gear is meshed with the transmission gear. An adjustment component is connected to the right side of the transmission gear, which can adjust the relative angle between the transmission gear and the positioning disk.

[0008] Preferably, a guide plate is fixed to the inner wall of the air outlet duct, and the guide plates are distributed in an equidistant array on the inner wall of the air outlet duct. A sound-absorbing pad is fixed to the inner wall of the volute.

[0009] By adopting the above technical solution, the airflow at the outlet can be regulated and guided by the equidistant array of guide plates on the inner wall of the air outlet duct, which can effectively avoid airflow turbulence and eddy current generation, reduce air supply resistance, and improve the air supply efficiency and uniformity of the ventilator. At the same time, the sound-absorbing pads added to the inner wall of the volute can effectively absorb the airflow noise and mechanical vibration noise generated during the operation of the fan, weaken the noise transmission from the source, further optimize the low-noise performance of the equipment, and improve the quietness of the equipment operation.

[0010] Preferably, the transmission assembly includes a bearing housing, which is fixed to the upper end of the support platform. A rotating shaft is rotatably connected to the middle of the bearing housing, and the left end of the rotating shaft is fixedly connected to the transmission shaft. A driven pulley is connected to the right end of the rotating shaft, and a power motor is installed on the rear side of the support platform. The shaft end of the power motor is connected to a driving pulley, and a transmission belt connects the driving pulley and the driven pulley.

[0011] The above technical solution adopts a transmission structure consisting of a bearing housing, a rotating shaft, a pulley, and a transmission belt. This structure is simple, easy to assemble, and has low maintenance costs. The belt drive has good buffering and shock absorption effects, which can effectively offset the vibration and impact of the motor operation, reduce noise and mechanical wear during transmission, and meet the low-noise operation requirements of the fan. At the same time, it can realize long-distance power transmission, has strong transmission stability, and can ensure the continuous and stable rotation of the fan blades, thus ensuring stable air delivery by the fan.

[0012] Preferably, the nozzles are distributed in an equidistant array, the outlet end of the water pump is connected to a guide pipe, the nozzles and the water pump are connected through the guide pipe, a liquid storage tank is installed inside the support platform, the inlet end of the water pump is connected to the liquid storage tank, and a drainage hole is provided at the bottom of the volute.

[0013] By adopting the above technical solution, a flushing structure consisting of a liquid storage tank, water pump, and guide pipe combined with an array of nozzles can be used to perform all-round spray cleaning of the inside of the volute and the surface of the blades. The system is highly automated, eliminating the need for manual cleaning by disassembly, which significantly reduces the difficulty of equipment maintenance and operating costs. In addition, the drainage holes at the bottom of the volute can promptly discharge flushing wastewater, preventing water and scale buildup inside the casing. This effectively prevents problems such as reduced airflow and increased operating noise caused by dust and scale buildup on the blades, continuously ensuring the ventilation efficiency of the fan and extending the service life of the equipment.

[0014] Preferably, the positioning disks are distributed in an equidistant array, with the center of the rightmost positioning disk fixedly connected to the drive shaft, and the blades are distributed in a ring array with the center point of the positioning disk as the axis. The limiting disks connected to the outer wall of the blades correspond to the positions and numbers of the positioning disks.

[0015] By adopting the above technical solution, multiple sets of positioning discs are evenly arranged and fixed, and the blades, limiting discs and positioning discs are arranged in a one-to-one circular array, which makes the blades uniformly stressed and has a good dynamic balance effect. It can effectively suppress vibration and abnormal noise during high-speed rotation and meet the low noise design requirements of the fan. The regular blade array structure can ensure stable and uniform centrifugal airflow, improve the overall air supply stability and ventilation efficiency of the fan, and at the same time provide a stable installation and operation foundation for the subsequent blade angle adjustment structure.

[0016] Preferably, the adjustment component includes a guide tube, which is sleeved on the outside of the transmission shaft. A strip-shaped groove is formed on the outer wall of the transmission shaft. The guide tube slides with the transmission shaft through the strip-shaped groove. A guide strip is connected to the outer wall of the guide tube. A limit groove is formed on the inner wall of the transmission gear plate. The limit groove slides with the guide strip.

[0017] The above technical solution utilizes the outer groove of the drive shaft to achieve axial sliding fit of the guide tube. At the same time, through the limiting fit between the guide strip and the limiting groove of the drive gear plate, the drive gear plate can be stably driven to rotate. The structure has high limiting accuracy and smooth sliding fit. It can accurately adjust the relative angle between the drive gear plate and the positioning plate, thereby achieving precise control of the blade working angle. The overall structure is compact, highly integrated, and the adjustment is reliable without interfering with the normal transmission operation of the fan.

[0018] Preferably, the left end of the guide bar is straight along the axis of the guide tube, the right end of the guide bar is obliquely arranged around the outer wall of the guide tube, and a return spring is sleeved on the outside of the left end of the drive shaft. The two ends of the return spring are respectively connected to the positioning plate and the guide tube on the right end.

[0019] Using the above technical solution, the guide bar adopts a composite structure with a straight front section and an oblique rear section. During the axial sliding of the guide tube, the oblique structure can automatically drive the transmission gear plate to deflect, which can complete the fine adjustment of the blade angle without the need for a complex transmission mechanism. The structure is ingenious and the adjustment stability is strong. With the addition of a reset spring, the guide tube and the transmission structure can be quickly and accurately reset, ensuring that the structure is reset in place after each angle adjustment. The adjustment repeatability is good, and the blade working angle can be flexibly switched according to the working conditions to adapt to different air volume and air pressure requirements.

[0020] Preferably, a transmission link is rotatably connected to the outer wall of the right side of the support platform. The transmission link is arranged in a "V" shape. A fork is fixed at the lower end of the transmission link. A guide groove is opened at the lower end of the fork. A limit ring is rotatably connected to the right end of the guide tube. Limit rods are fixed at both ends of the limit ring. The limit rods extend into the guide groove and slide with it.

[0021] By adopting the above technical solution, a linkage structure of V-shaped transmission connecting rod, shift fork, limit rod and limit ring can be used to smoothly convert the rotation of the connecting rod into the axial sliding displacement of the guide tube, resulting in smooth power transmission and high transmission efficiency. Through the sliding limit cooperation between the limit rod and the guide groove of the shift fork, the deviation and sway of the guide tube can be effectively restricted, avoiding problems such as jamming, sticking and deviation during the adjustment process, and greatly improving the stability of the blade angle adjustment process and the reliability of equipment operation.

[0022] Preferably, an electric push rod is rotatably connected to the outer wall of the right side of the support platform, and the telescopic shaft end of the electric push rod is rotatably connected to the transmission connecting rod.

[0023] By adopting the above technical solution, an electric push rod is used as the adjustment drive source to drive the transmission linkage to complete the linkage adjustment, thereby realizing the automatic electronic control adjustment of the blade angle, replacing the traditional manual adjustment. The adjustment is convenient and efficient, with high control precision and fast response speed.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: This multi-blade low-noise centrifugal fan can effectively regulate the airflow through the array of guide plates arranged on the inner wall of the outlet duct, eliminate airflow turbulence and eddy currents, reduce air supply resistance, and significantly improve the air supply efficiency and uniformity of the fan; at the same time, the sound-absorbing pads set on the inner wall of the volute can absorb airflow noise and mechanical vibration noise from the sound source, weakening noise transmission; the equipment adopts a belt drive structure, relying on the buffering and shock absorption characteristics of the belt to offset the vibration and impact generated by the operation of the power motor, reducing mechanical transmission noise and wear; combined with the uniform array blade structure, it ensures the dynamic balance of blade rotation, suppresses vibration and abnormal noise during high-speed operation, and achieves low-noise and high-stability operation of the equipment in all aspects.

[0025] 1. The equipment forms an all-round spray rinsing system through a liquid storage tank, water pump, guide pipe and array nozzles, which can clean the inside of the volute and the surface of the blades without dead angles. There is no need to disassemble the machine for manual cleaning, which greatly reduces the difficulty of equipment maintenance and labor costs. At the same time, the drainage holes opened at the bottom of the volute can drain the rinsing wastewater in time, avoiding water and scale accumulation inside the casing. This eliminates the problems of reduced air volume, poor air supply and increased operating noise caused by dust and scale accumulation on the blades from the root, continuously and stably ensuring the ventilation performance of the fan, effectively delaying equipment wear and tear, and improving the stability and durability of the equipment in long-term operation. 2. Through the meshing of the guide tube, guide strip, transmission gear plate, and transmission gear, combined with the oblique transmission principle of the composite structure guide strip, the working angle of the blades can be precisely controlled. The structure is compact, the adjustment is precise, and it will not interfere with the normal transmission of the fan. With the V-shaped transmission linkage, the shift fork linkage structure, and the electric push rod electric control drive, the blade angle can be automatically and with high precision, replacing the traditional manual adjustment mode. The adjustment response is fast and the repeatability is good. At the same time, the return spring can ensure that the adjustment structure can quickly and accurately return to its original position, ensuring that the equipment can flexibly switch the blade working state according to the working conditions of different air volume and air pressure, greatly expanding the applicable scenarios of the fan and improving the overall practical value of the equipment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention from another perspective; Figure 3 This is a schematic diagram of the transmission component structure of the present invention; Figure 4 This is a schematic diagram of the adjustment component structure of the present invention; Figure 5 This is a schematic diagram of the flow guide tube and nozzle structure of the present invention; Figure 6 This is a schematic diagram of the volute and drainage hole structure of the present invention; Figure 7 This is a schematic diagram of the transmission gear and transmission disc structure of the present invention; Figure 8 This is a schematic diagram of the positioning disk and blade structure of the present invention; Figure 9 This is a schematic diagram of the transmission gear plate and limiting groove structure of the present invention; Figure 10 This is a schematic diagram of the guide tube and guide strip structure of the present invention; Figure 11 This is a schematic diagram of the blade and limiting disk structure of the present invention; Figure 12 This is a schematic diagram of the limiting plate and positioning plate structure of the present invention.

[0027] In the diagram: 1. Support platform; 2. Volute; 3. Air inlet hood; 4. Air outlet duct; 5. Guide plate; 6. Bearing seat; 7. Rotating shaft; 8. Drive shaft; 9. Positioning plate; 10. Blade; 11. Driven pulley; 12. Power motor; 13. Drive pulley; 14. Drive belt; 15. Water pump; 16. Liquid storage tank; 17. Guide pipe; 18. Nozzle; 19. Drain hole; 20. Limiting plate; 21. Drive gear; 22. Drive gear plate; 23. Limiting groove; 24. Guide tube; 25. Guide strip; 26. Limiting ring; 27. Limiting rod; 28. Drive linkage; 29. ​​Shift fork; 30. Electric push rod; 31. Sound-absorbing pad; 32. Return spring. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1-12This invention provides a technical solution: a multi-blade low-noise centrifugal fan, including a support platform 1 and a volute 2 mounted on its side. The support platform 1 serves as an integral load-bearing base, constructed from welded steel profiles, resulting in a stable overall structure with strong load-bearing capacity, allowing direct placement on the ground, equipment racks, or other mounting surfaces. An air inlet hood 3 is connected to the left end of the volute 2. The volute 2 is the core shell structure of the centrifugal fan, constructed from sheet metal through stamping, bending, and welding, forming a snail-shaped streamlined cavity to ensure smooth airflow. The volute 2 is fixed to the support platform 1 with bolts. An air outlet duct 4 is connected to the upper end of the volute 2, with guide plates 5 fixed to the inner wall of the duct 4. The guide plates 5 are evenly distributed on the inner wall of the duct 4. A sound-absorbing pad 31 is fixed to the inner wall of the volute 2. A drive shaft 8 runs through the right side of the volute 2, with a positioning disc 9 connected to the left end of the drive shaft 8. The outer edge of the positioning disc 9... The fan is connected to blades 10 and a transmission assembly is connected to the right end of the drive shaft 8. The transmission assembly drives the drive shaft 8 to rotate to provide power to the fan. The transmission assembly includes a bearing housing 6, which is fixed to the upper end of the support platform 1. A rotating shaft 7 is rotatably connected to the middle of the bearing housing 6. The left end of the rotating shaft 7 is fixedly connected to the drive shaft 8. A driven pulley 11 is connected to the right end of the rotating shaft 7. A power motor 12 is installed on the rear side of the support platform 1. A drive pulley 13 is connected to the shaft end of the power motor 12. A transmission belt 14 is connected between the drive pulley 13 and the driven pulley 11. After the equipment is powered on, the power motor 12 starts, driving the drive pulley 13 to rotate, which in turn drives the driven pulley 11 to rotate synchronously via the transmission belt 14. The driven pulley 11 drives the rotating shaft 7, transmission shaft 8, positioning disc 9, and blades 10 to rotate synchronously. External air is gathered by the air inlet shroud 3 and enters the volute 2. The high-speed rotating blades 10 pressurize the airflow, which flows along the cavity of the volute 2 to the top outlet duct 4. The airflow is rectified by the guide plates 5 arranged in an array inside the outlet duct 4 and then smoothly discharged outward. Throughout the operation, the sound-absorbing pads 31 on the inner wall of the volute 2 absorb the noise inside the casing, and the guide plates 5 reduce the airflow noise. Combined with the smooth operation and low vibration of the belt drive, the entire ventilator achieves stable operation with low noise and high flow rate.

[0030] A rinsing assembly is installed on the side of the support platform 1. The rinsing assembly includes a water pump 15 and nozzles 18. The nozzles 18 are connected to the side wall of the volute 2 and the water pump 15. The nozzles 18 are distributed in an equidistant array. The outlet end of the water pump 15 is connected to a guide pipe 17. The nozzles 18 and the water pump 15 are connected through the guide pipe 17. A liquid storage tank 16 is installed inside the support platform 1. The inlet end of the water pump 15 is connected to the liquid storage tank 16. A drain hole 19 is opened at the bottom of the volute 2. In order to avoid dust accumulation on the surface of the blades 10 and increase the operating noise, the rinsing assembly is set to rinse the blades 10 regularly. When working, the water pump 15 is started, and the rinsing liquid in the liquid storage tank 16 is drawn out by the water pump 15, and after being diverted through the guide pipe 17, it is delivered to each nozzle 18. The array of nozzles 18 can spray and clean the blades 10 from different positions. After spraying, the waste liquid is collected at the bottom of the volute 2 by gravity and finally discharged outward through the drain hole 19, which avoids the accumulation of waste liquid inside the volute 2 and keeps the inside of the equipment clean and dry.

[0031] A limiting disk 20 is connected to the outer wall of the blade 10. The limiting disk 20 is rotatably connected to the positioning disk 9. The limiting disk 20 has a protruding design in the middle. The positioning disk 9 and the limiting disk 20 have a matching groove structure at the mating position, which can improve the stability of the limiting disk 20 and the blade 10 during rotation, and at the same time limit the relative axial displacement between the positioning disk 9 and the limiting disk 20. A transmission gear 21 is connected to the right side of the limiting disk 20. A transmission gear 22 is rotatably mounted on the right side of the positioning disk 9. The outer wall of the transmission gear 22 is meshed with the transmission gear 21. An adjustment component is connected to the right side of the transmission gear 22, which can adjust the relative angle between the transmission gear 22 and the positioning disk 9. The positioning disks 9 are evenly distributed in an array. The middle of the rightmost positioning disk 9 is fixed to the transmission shaft 8. The blades 10 are arranged in a ring array around the center point of the positioning disk 9, and the limiting disks 20 connected to the outer wall of the blades 10 correspond to the positions and numbers of the positioning disks 9. During operation, the external power drives the transmission shaft 8 to rotate, and the transmission shaft 8 drives the positioning disks 9 to rotate synchronously, so that the blades 10 make overall circular motion with the positioning disks 9. If it is necessary to change the working angle of the blades 10, the adjustment component is activated to adjust the rotation angle of the transmission gear disk 22 relative to the positioning disk 9. Through the meshing transmission gear 21, the deflection angle of the blades 10 is adjusted one by one. The dynamic adjustment of the attitude of the blades 10 is completed under the continuous operation of the device to meet the needs of different working conditions. The blades 10 are rotatably connected to the positioning disks 9 through the limiting disks 20 to ensure stability during rotation and angle adjustment.

[0032] The adjustment assembly includes a guide tube 24, which is sleeved on the outside of the drive shaft 8. A strip-shaped groove is formed on the outer wall of the drive shaft 8, and the guide tube 24 slides through this groove. A guide strip 25 is connected to the outer wall of the guide tube 24. A limiting groove 23 is formed on the inner wall of the transmission gear disc 22, and the limiting groove 23 slides with the guide strip 25. The left end of the guide strip 25 is straight along the axis of the guide tube 24, and the right end of the guide strip 25 is obliquely arranged around the outer wall of the guide tube 24. A return spring 32 is sleeved on the outside of the left end of the drive shaft 8. Both ends are connected to the right-side positioning plate 9 and guide tube 24 respectively; a transmission link 28 is rotatably connected to the right outer wall of the support platform 1. The transmission link 28 is arranged in a "V" shape, and a fork 29 is fixed at the lower end of the transmission link 28. A guide groove is opened at the lower end of the fork 29. A limit ring 26 is rotatably connected to the right end of the guide tube 24. Limit rods 27 are fixed at both ends of the limit ring 26. The limit rods 27 extend into the guide groove and slide with it; an electric push rod 30 is rotatably connected to the right outer wall of the support platform 1. The telescopic shaft end of the electric push rod 30 is rotatably connected to the transmission link 28. When it is necessary to adjust the air volume of the fan, the angle of the blades 10 can be adjusted. At the same time, when it is necessary to flush the blades 10, their angle can also be adjusted to reduce the flushing dead angle. When the electric push rod 30 is activated, its telescopic shaft extends, pushing the V-shaped transmission link 28 to swing downwards around the hinge point. The transmission link 28 drives the lower fork 29 to swing synchronously. The fork 29 pulls the limiting ring 26 and the guide tube 24 along the transmission shaft 8 to slide axially to the right through the guide groove and the limiting rod 27. During the sliding process, the guide bar 25 moves along the limiting groove 23 on the inner wall of the transmission gear disk 22. The inclined section of the guide bar 25 cooperates with the limiting groove 23 to complete the guidance, driving the transmission gear disk 22 to rotate, and the relative angle with the transmission shaft 8 changes. At the same time, the guide tube 24 compresses the return spring 32 on the left side, and the spring stores elastic potential energy. Due to the limiting effect of the strip groove on the outer wall of the transmission shaft 8, the guide tube 24 only slides axially and does not rotate circumferentially with the transmission gear disk 22. When the electric push rod 30 extends to the specified stroke and stops, the transmission link 28 and the shift fork 29 remain in a fixed position, and the guide tube 24 stays at the target axial position, completing the locking of the blade 10 angle. When it is necessary to reset the blade 10 angle, the electric push rod 30 retracts and resets, pulling the transmission link 28 to swing in the opposite direction. At this time, the compressed reset spring 32 releases its elastic potential energy and pushes the guide tube 24 to the left along the transmission shaft 8 and the guide bar 25 along the limiting groove 23 to slide synchronously to the left until it returns to the initial position, completing one complete adjustment cycle. When the guide tube 24 is in the initial position, the straight section on the left side of the guide bar 25 remains engaged with the limiting groove 23, which can limit the change of the relative angle between the transmission shaft 8, the positioning plate 9 and the transmission gear plate 22.

[0033] The contents not described in detail in this specification are prior art known to those skilled in the art. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-blade low-noise centrifugal fan, comprising a support platform (1) and a volute (2) mounted on its side, characterized in that: The left end of the volute (2) is connected to an air inlet hood (3), the upper end of the volute (2) is connected to an air outlet pipe (4), the right side of the volute (2) is connected to a drive shaft (8), the left end of the drive shaft (8) is connected to a positioning plate (9), the outer edge of the positioning plate (9) is connected to a blade (10), the right end of the drive shaft (8) is connected to a transmission assembly, and the transmission assembly drives the drive shaft (8) to rotate to provide power for the fan; The support platform (1) is equipped with a flushing assembly on its side. The flushing assembly includes a water pump (15) and a nozzle (18). The nozzle (18) is connected to the side wall of the volute (2) and is connected to the water pump (15). The outer wall of the blade (10) is connected to a limiting disk (20), which is rotatably connected to the positioning disk (9). A transmission gear (21) is connected to the right side of the limiting disk (20), and a transmission gear (22) is rotatably installed on the right side of the positioning disk (9). The outer wall of the transmission gear (22) is meshed with the transmission gear (21), and an adjustment component is connected to the right side of the transmission gear (22). The adjustment component can adjust the relative angle between the transmission gear (22) and the positioning disk (9).

2. The multi-blade low-noise centrifugal fan according to claim 1, characterized in that: The air outlet pipe (4) has a guide plate (5) fixed on its inner wall. The guide plates (5) are distributed in an equidistant array on the inner wall of the air outlet pipe (4). The volute (2) has a sound-absorbing pad (31) fixed on its inner wall.

3. The multi-blade low-noise centrifugal fan according to claim 1, characterized in that: The transmission assembly includes a bearing seat (6), which is fixed to the upper end of the support platform (1). A rotating shaft (7) is rotatably connected to the middle of the bearing seat (6), and the left end of the rotating shaft (7) is fixedly connected to the transmission shaft (8). The right end of the rotating shaft (7) is connected to a driven pulley (11), and a power motor (12) is installed on the rear side of the support platform (1). The shaft end of the power motor (12) is connected to a driving pulley (13), and a transmission belt (14) is connected between the driving pulley (13) and the driven pulley (11).

4. The multi-blade low-noise centrifugal fan according to claim 1, characterized in that: The nozzles (18) are distributed in an equidistant array. The outlet end of the water pump (15) is connected to a guide pipe (17). The nozzles (18) and the water pump (15) are connected through the guide pipe (17). A storage tank (16) is installed inside the support platform (1). The inlet end of the water pump (15) is connected to the storage tank (16). A drain hole (19) is opened at the bottom of the volute (2).

5. The multi-blade low-noise centrifugal fan according to claim 1, characterized in that: The positioning disks (9) are distributed in an equidistant array. The middle part of the rightmost positioning disk (9) is fixedly connected to the transmission shaft (8). The blades (10) are distributed in a ring array with the center point of the positioning disk (9) as the axis. The limiting disks (20) connected to the outer wall of the blades (10) correspond to the positions and numbers of the positioning disks (9).

6. The multi-blade low-noise centrifugal fan according to claim 1, characterized in that: The adjustment assembly includes a guide tube (24), which is sleeved on the outside of the transmission shaft (8). The outer wall of the transmission shaft (8) has a strip groove. The guide tube (24) slides with the transmission shaft (8) through the strip groove. The outer wall of the guide tube (24) is connected to a guide strip (25). The inner wall of the transmission gear plate (22) has a limiting groove (23), which slides with the guide strip (25).

7. The multi-blade low-noise centrifugal fan according to claim 6, characterized in that: The left end of the guide bar (25) is straight along the axis of the guide tube (24), and the right end of the guide bar (25) is obliquely arranged around the outer wall of the guide tube (24). The left end of the drive shaft (8) is fitted with a reset spring (32), and the two ends of the reset spring (32) are connected to the positioning plate (9) and the guide tube (24) on the right end, respectively.

8. The multi-blade low-noise centrifugal fan according to claim 6, characterized in that: The support platform (1) is rotatably connected to the outer wall of the right side by a transmission link (28). The transmission link (28) is set in a "V" shape. The lower end of the transmission link (28) is fixed with a fork (29). The lower end of the fork (29) is provided with a guide groove. The right end of the guide tube (24) is rotatably connected with a limit ring (26). The two ends of the limit ring (26) are fixed with limit rods (27). The limit rods (27) extend into the guide groove and slide with it.

9. The multi-blade low-noise centrifugal fan according to claim 8, characterized in that: An electric push rod (30) is rotatably connected to the outer right side of the support platform (1), and the telescopic shaft end of the electric push rod (30) is rotatably connected to the transmission link (28).

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