CN107014048B

CN107014048B - Fan air duct system and air purifier comprising same

Info

Publication number: CN107014048B
Application number: CN201710404371.XA
Authority: CN
Inventors: 袁卫东
Original assignee: Nantong Shichuang Electronic Technology Co ltd
Current assignee: Nantong Shichuang Electronic Technology Co ltd
Priority date: 2017-06-01
Filing date: 2017-06-01
Publication date: 2023-04-07
Anticipated expiration: 2037-06-01
Also published as: CN107014048A

Abstract

The invention provides a fan air duct system which comprises a wind wheel, a motor, a volute air duct upper shell and a volute air duct lower shell, wherein the wind wheel is arranged in a cavity formed by connecting the volute air duct upper shell and the volute air duct lower shell; the front of wind wheel is equipped with a plurality of long flabellums and a plurality of short flabellums, one side of long flabellum with one side of short flabellum all is the perpendicular, the opposite side of long flabellum with the opposite side of short flabellum is the arc, the rear end of long flabellum is fixed and is being close to the outer edge department of wind wheel, the front end of long flabellum is fixed the center department of wind wheel. The fan air duct system and the air purifier comprising the same effectively improve the integral air supply quantity of the fan through optimizing the design and the structure of the wind wheel and the integral fan formed by matching the wind wheel with the motor, and achieve the purposes of saving energy, protecting environment and improving the use experience of customers.

Description

Fan air duct system and air purifier comprising same

Technical Field

The invention relates to the field of fan air duct systems, in particular to a fan air duct system and an air purifier comprising the same.

Can be applied to various air purification devices such as a portable air purifier, a household air purifier or a vehicle-mounted air purifier

Background

In the field of existing fan duct systems, a general fan duct system will typically include the following basic structure and components:

1. fan blades/wind wheels: there are many forms, such as computer cooling fans.

2. A motor: in a small fan, it is common to integrate the fan, such as a heat dissipation fan.

3. Air duct: the air duct is generally volute-shaped, and for the convenience of assembly, the air duct is generally composed of an upper cover and a lower cover.

4. An air inlet: generally in the center of the fan blade.

5. Air outlet/air outlet channel: generally at the widest point of the volute.

The working principle of the existing fan air duct system is as follows: the motor can drive the fan blades to rotate after being electrified, the fan blades rotate to form suction, and outside air is guided into the volute air duct through the air inlet. The conventional fan air duct system has different drainage effects according to different fan blade designs. The airflow is gradually pressurized through the volute air duct and is forcibly sent out through the air outlet.

The application range of the fan air duct system is as follows: if the air purifier is applied, the filter element can be placed at the front end of the air inlet of the fan. According to different filter effects, the wind resistance of the filter element is different, the better the filter effect is, the higher the wind resistance is. Under the same condition of the fan and the air duct, the better the filtering effect is, and the less the air is finally sent out through the air outlet.

Therefore, the following problems exist in the existing fan air duct system: 1. although the size of a common small/micro fan is portable, the rotating speed is slow (3000-6500 r/min), so the air volume is small. Usually less than 40 to 50L/min. Therefore, the grade of the usable filter element is lower, and the filtering effect is different. In severe PM2.5 conditions or regions, the filtration efficacy is far from healthy levels.

2. If the filter element with good filtering effect is selected, the wind resistance is large, the air supply is small, the user experience effect is poor, and sometimes even suffocation is generated due to insufficient air volume.

3. If the blower with a slightly larger volume, a higher rotating speed and a stronger force is selected, the energy consumption of the product can be increased, and the service time of the portable product is shortened. Some similar products on the market have only 3-5 hours of endurance, and the normal use and use experience of users are seriously influenced.

4. Selecting a slightly larger blower can result in increased weight and vibration.

In view of the above, those skilled in the art are in urgent need to develop a new type of fan duct system to overcome the above-mentioned drawbacks of the prior art.

Disclosure of Invention

The invention aims to overcome the defects of poor filtering effect, large volume and the like of a fan air duct system in the prior art, and provides the fan air duct system and an air purifier comprising the same.

The invention solves the technical problems through the following technical scheme:

a fan air duct system is characterized by comprising a wind wheel, a motor, a volute air duct upper shell and a volute air duct lower shell, wherein the wind wheel is installed in a cavity formed by connecting the volute air duct upper shell and the volute air duct lower shell, and a shaft of the motor penetrates through the volute air duct lower shell to be connected with the wind wheel;

the front of wind wheel is equipped with a plurality of long flabellums and a plurality of short flabellums, one side of long flabellum with one side of short flabellum all is the perpendicular, the opposite side of long flabellum with the opposite side of short flabellum is the arc, the rear end of long flabellum is fixed and is being close to the outer edge department of wind wheel, the front end of long flabellum is fixed the center department of wind wheel.

According to one embodiment of the invention, the long fan blades and the short fan blades are uniformly distributed on the front surface of the wind wheel in an annular shape.

According to one embodiment of the present invention, the long fan blade has an airfoil shape, and the width of the long fan blade gradually widens as the long fan blade extends from the front end to the rear end.

According to one embodiment of the present invention, the rear end of the long blade is narrower than the widest point of the long blade, and the rear end of the long blade is wider than the front end of the long blade.

According to one embodiment of the present invention, the short blade has a minor arc shape, and the middle portion of the short blade is wider than the front and rear ends of the short blade.

According to one embodiment of the present invention, the long blades and the short blades are alternately arranged, and one short blade is disposed between every two long blades.

According to one embodiment of the invention, the length ratio of the long fan blade to the short fan blade is 1;

the ratio of the widest part to the narrowest part of the long fan blade is 1 to 0.1-1, and the ratio of the widest part to the narrowest part of the short fan blade is 1 to 0.4-1.

According to one embodiment of the invention, a cylindrical boss is arranged at the center of the wind wheel, the top of the boss is conical, a concentric hole is arranged at the center of the boss, a metal sleeve is arranged in the concentric hole, and the motor is fixedly connected with the wind wheel through the sleeve.

According to one embodiment of the invention, the top of the boss is flat near the outer edge, and the front end part of the long fan blade is arranged on the flat surface of the boss.

According to one embodiment of the invention, the reverse side of the boss of the wind wheel is concave; the depth of the concave shape is 0.5-2cm, and the inner diameter of the concave shape is 1-3cm.

According to one embodiment of the invention, the outer edge of the reverse side of the wind wheel is provided with a balancing rib in a circle; the height ratio of the balancing ribs to the long fan blades and the short fan blades is 1.35-1.

According to one embodiment of the invention, the front surface of the upper volute air duct shell is provided with a circular air inlet, and the back surface of the upper volute air duct shell is provided with a row of salient points which are arranged along the edge of the shell of the upper volute air duct shell;

the front side of the lower volute air duct shell is provided with a cylindrical hollow motor fixing seat, and the back side of the lower volute air duct shell is provided with a row of holes which are arranged along the edge of the shell of the lower volute air duct shell;

the salient points correspond to the holes to form assembly and are fixed with each other.

According to one embodiment of the invention, an air outlet duct is arranged on the outer side of the upper volute casing.

The invention also provides an air purifier which is characterized by comprising the fan air duct system.

The positive progress effects of the invention are as follows:

the fan air duct system and the air purifier comprising the same effectively improve the integral air supply quantity of the fan by optimizing the design and the structure of the wind wheel and the integral fan formed by matching the wind wheel with the motor. Meanwhile, the energy efficiency of the fan is enhanced by optimizing the technology and the design of the wind wheel and the matched motor, and the service life of the product is prolonged under the same power capacity, so that the aims of saving energy, protecting the environment and improving the use experience of customers are fulfilled.

The fan air duct system and the air purifier comprising the same can increase the rotating speed of a fan to be more than 10000r/min, and the air quantity can reach more than 90L/min, which is about twice of that of the common existing products. And the energy consumption is low, and the current consumption is about 1/2 of that of the common existing products under the same voltage.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings in which like reference numerals denote like features throughout the several views, wherein:

fig. 1 is a schematic overall structural diagram of a fan duct system according to a first embodiment of the present invention.

FIG. 2 is a front view of a wind wheel in a first embodiment of a wind tunnel system of a wind turbine according to the present invention.

Fig. 3 is a schematic view illustrating the assembly of the wind wheel, the motor and the lower casing of the spiral duct according to the first embodiment of the fan duct system of the present invention.

Fig. 4 is a schematic structural diagram of an upper volute casing of a fan duct system according to an embodiment of the present invention.

Fig. 5 is a schematic structural view of a lower casing of a volute air duct according to an embodiment of the blower duct system of the present invention.

Fig. 6 is a schematic structural view of an upper volute casing of a fan duct system according to a second embodiment of the present invention.

Fig. 7 is a schematic structural view of an air outlet duct in a second embodiment of the fan duct system of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference is made to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Further, although the terms used in the present invention are selected from publicly known and used terms, some of the terms mentioned in the description of the present invention may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Furthermore, it is required that the present invention is understood, not simply by the actual terms used but by the meaning of each term lying within.

The first embodiment is as follows:

fig. 1 is a schematic overall structural diagram of a fan duct system according to a first embodiment of the present invention. FIG. 2 is a front view of a wind wheel in a first embodiment of a wind tunnel system of a wind turbine according to the present invention. Fig. 3 is a schematic view illustrating the assembly of the wind wheel, the motor and the lower casing of the spiral duct according to the first embodiment of the fan duct system of the present invention. Fig. 4 is a schematic structural diagram of an upper volute casing of a fan duct system according to an embodiment of the present invention. Fig. 5 is a schematic structural view of a lower casing of a volute air duct according to an embodiment of the blower duct system of the present invention.

As shown in fig. 1 to 2, the present invention discloses a fan duct system, which includes a wind wheel 10, a motor 20, a scroll duct upper shell 30 and a scroll duct lower shell 40. The wind wheel 10 is installed in a cavity formed by connecting the upper volute casing 30 and the lower volute casing 40, and the shaft of the motor 20 penetrates into the lower volute casing 40 to be connected with the wind wheel 10. The front of the wind wheel 10 is provided with a plurality of long blades 11 and a plurality of short blades 12, one side of the long blades 11 and one side of the short blades 12 are both vertical surfaces, the other side of the long blades 11 and the other side of the short blades 12 are arc-shaped, the rear end 11b of the long blades 11 is fixed at the position close to the outer edge of the wind wheel 10, and the front end 11a of the long blades 11 is fixed at the center of the wind wheel 10.

Preferably, the wind wheel 10 in this embodiment is made of a material that is tough and can withstand high rotational speed, so that the strength and the service life of the wind wheel can be effectively improved, and vibration and noise can be reduced. The long fan blades 11 and the short fan blades 12 are uniformly distributed on the front surface of the wind wheel 10 in an annular shape. The long blade 11 has an airfoil shape, and the width of the long blade 11 gradually increases from the front end 11a to the rear end 11 b.

Therefore, the tip 11a of the long blade 11 is the narrowest width. That is, rear end 11b of long blade 11 is narrower than the widest part of long blade 11, and rear end 11b of long blade 11 is wider than front end 11a of long blade 11. The short blade 12 has a minor arc shape, and the middle portion of the short blade 12 is wider than the front and rear ends of the short blade 12.

As described above, the front ends of the long fan blade 11 and the short fan blade 12 are both narrow ends, and both point to the direction of the central boss of the wind wheel. The long fan blades 11 and the short fan blades 12 are evenly arrayed on the front face of the wind wheel in an annular shape, and according to the positioning and pointing directions of the long fan blades 11 and the short fan blades 12, if extension lines are made towards the central boss direction of the wind wheel 10 along one side of the vertical plane of all the long fan blades 11 and the short fan blades 12, the extension lines can penetrate through the central boss position of the wind wheel 10, and the extension lines of the vertical plane of all the long fan blades 11 and the short fan blades 12 can intersect at the central boss position of the wind wheel 10.

The design provides high-efficiency guarantee for the air inlet efficiency and the ventilation quantity of the fan and the air duct system. When the wind wheel rotates at high speed, the airflow is uniformly transmitted to the front end of the wing-shaped long fan blade through the streamline radian of the conical boss. Because the front end is narrower, the rear end is wider, and pressure difference is generated by the structure that one side of the fan blade is arc-shaped and the other side is vertical, the airflow generates strong power, and the ventilation effect of the whole fan is enhanced.

However, the uniform arrangement of the long fan blades 11 and the short fan blades 12, especially the feature that the extension lines of the vertical surfaces thereof can intersect at the central point of the wind wheel, ensures the stability and consistency of the airflow rotation, and avoids the formation of turbulent flow and irregular airflow vortex, thereby reducing the airflow loss and enhancing the overall ventilation. In the process of reducing the turbulent flow, the design also ensures that the fan cannot be influenced by the turbulent flow when working and needs to provide extra current to resist the resistance brought by the airflow. Therefore, the design also enables the fan to work more efficiently and save more energy.

Preferably, the most preferable number of the long fan blades 11 and the short fan blades 12 in the present embodiment is nine, and of course, the number of the fan blades is adjusted according to the diameter and the size of the fan, and is within the protection scope of the present invention. The long blades 11 and the short blades 12 are uniformly arranged alternately, that is, one short blade 12 is arranged between every two long blades 11. Similarly, a long blade 11 is disposed between every two short blades 12.

In particular, here, the length ratio of long blade 11 to short blade 12 is preferably 1. The ratio of the widest part to the narrowest part of the long fan blade 11 is preferably 1.

Further preferably, a cylindrical boss 13 is arranged at the center of the wind wheel 10, the top of the boss 13 is conical, a concentric hole 14 is arranged at the center of the boss 13, a metal sleeve 15 is installed in the concentric hole 14, and the motor 20 is fixedly connected with the wind wheel 10 through the sleeve 15. The design ensures that the motor shaft and the wind wheel 10 are higher in close fit and more wear-resistant, and reduces extra resistance brought by long-term high-speed rotation or wear. Therefore, the use energy efficiency of the fan is enhanced, the air quantity loss caused by friction resistance is reduced, and the air quantity generated by the whole fan is improved.

Specifically, here, the top of the boss 13 is flat near the outer edge, and the front end 11a of the long blade 11 is partially disposed at the plane of the boss 13. The boss 13 is gradually conical from outside to inside. The conical design can reduce the wind resistance when air flow is sucked, and is more beneficial to the efficiency of leading the air flow into the volute air duct by the long fan blade 11 of the wind wheel 10, thereby improving the air quantity generated by the whole fan. In addition, due to the improvement of the air supply efficiency, the low-efficiency operation caused by factors such as turbulent flow, wind resistance and the like can be effectively avoided, so that the current loss of the fan under the same condition is reduced, and the energy efficiency is improved.

The reverse side of the boss 13 of the wind wheel 10 is a concave 16, and the depth and the diameter of the concave are set by matching with the motor 20. The depth of the concave 16 is preferably 0.5 to 2cm, and the inner diameter of the concave 16 is preferably 1 to 3cm. Of course, it may also be appropriate to the actual electrical machine being distributed, without departing from the scope of protection of the present invention.

As shown in fig. 3, a balancing rib 17 is arranged on the outer periphery of the reverse side of the wind wheel 10, wherein the height ratio of the balancing rib 17 to the long fan blade 11 and the short fan blade 12 is 1. When the wind wheel 10 runs at a high speed, the balance rib 17 can ensure the stability of the rotation of the wind wheel, and the deflection degree of the wind wheel 10 is relieved by balancing the vibration of the wind wheel, so that the formation of turbulent flow is avoided, the loss of air flow is reduced, and the integral ventilation capacity is enhanced. The design improves the ventilation quantity, simultaneously reduces the current waste caused by low-efficiency operation such as turbulent flow and other factors due to the improvement of the operation efficiency, saves more energy and improves the overall energy efficiency of the fan.

As shown in fig. 4 and 5, in combination with fig. 3, the front surface of the upper casing 30 of the spiral duct in this embodiment is provided with a circular air inlet 31, and the back surface thereof is provided with a row of bumps 32, wherein the bumps 32 are arranged along the edge of the casing of the upper casing 30 of the spiral duct. The front of the lower scroll duct shell 40 is provided with a cylindrical hollow motor fixing seat 50, and the back is provided with a row of holes 41, and the holes 41 are arranged along the edge of the shell of the lower scroll duct shell 40. The bumps 32 and the holes 41 correspond to each other, and are assembled and fixed to each other. Of course, the air inlet 31 may have other geometric shapes without departing from the scope of the present invention.

Preferably, the diameter ratio of the air inlet 31 to the wind wheel 10 is preferably 1. If the diameter of the air inlet 31 is too small, the air suction effect of the fan is weakened, and the whole air volume is influenced. If the diameter of the air inlet 31 is relatively too large, the air wheel is easy to make the sucked air flow form a certain turbulent flow when rotating at high speed, so that the air resistance is increased, the air supply efficiency is influenced, and the whole air volume is reduced.

Further preferably, in the present embodiment, the thickness of the protruding point 32 of the upper casing 30 of the scroll air duct is matched with the thickness of the hole 41 of the lower casing 40 of the scroll air duct, the protruding point 32 is inserted into the hole 41 to form an assembly, and the upper casing and the lower casing are tightly and firmly fixed by using a hot melting process. Therefore, the sealing performance of the volute air channel can be effectively improved, the air flow is reduced, the air flow is lost and forms turbulent flow through air channel gaps when rotating at a high speed, the wind resistance is reduced, and the whole air quantity is increased. Of course, the above structure is a preferred solution, and other fixed connection manners, such as a snap, a screw, etc., may be adopted for the upper scroll casing 30 and the lower scroll casing 40 without departing from the protection scope of the present invention.

Furthermore, an air outlet duct 60 is disposed on the outer side of the upper volute casing 30 and located on the outermost side of the upper volute casing 30, and a volute flow deflector 42 is disposed on the lower volute casing 40. When the wind wheel 10 works, the wind wheel can rotate anticlockwise, airflow is guided by the long fan blades 11 after passing through the air inlet 31, the short fan blades 12 are pushed in a matched mode, then the airflow flows along the volute flow guide plates 42, the wind pressure is gradually increased through the volute air channel from small to large, and the airflow is discharged from the air outlet air channel 60. When the pressure is increased to the maximum value, the wind is radially thrown out and released under the action of centrifugal force when the wind force is strongest. The air outlet duct 60 is preferably designed vertically, so that the bending and obstruction inside the duct can be avoided, the turbulence and loss generated when the air volume passes through the duct are reduced, and the overall air volume is enhanced.

In this embodiment, the motor fixing seat 50 is connected to the lower scroll duct shell 40, the motor fixing seat 50 is cylindrical, and the inside 51 of the fixing seat is hollow, and the inner diameter of the fixing seat is matched with the outer diameter of the motor 20, so as to fix the motor 20.

The motor 20 of the present invention is preferably a high speed dc brushed motor that cooperates with the wind wheel 1 to produce a number of advantages over the prior art. The volume is small, the torsion is large, the rotating speed is high and can reach more than 10000r/min, which is more than twice of the rotating speed 4000-6000 r/min of the fan of the common portable air purifier, thereby greatly improving the whole air quantity of the fan. The maximum ventilation capacity of the invention can reach more than 95L/min, which is nearly twice of 45-52L/min of the common technology on the market.

The energy consumption is low, under the condition of the same voltage, the current consumption of a fan of a common portable air purifier is 400-600 mA, and the current consumption of the motor is about 1/3 of the current consumption of the common portable air purifier and is less than 150mA. The high-speed direct current brush motor is more suitable for load operation, and the energy consumption is lower behind the load, consequently can be arranged in the drive needs high-grade air purifier who crosses the filter core, and can reduce the energy consumption, increase duration, promote user experience.

In addition, the invention also provides an air purifier, which is characterized in that the air purifier adopts the fan air duct system, such as a portable air purifier, a household air purifier or a vehicle-mounted air purifier.

In summary, the fan air duct system and the air purifier comprising the same effectively improve the integral air supply volume of the fan by optimizing the design and the structure of the wind wheel and the integral fan formed by matching the wind wheel with the motor. Meanwhile, the energy efficiency of the fan is enhanced by optimizing the technology and design of the wind wheel and the matched motor, and the service life of the product is prolonged under the same power capacity, so that the aims of saving energy, protecting environment and improving the use experience of customers are fulfilled.

Simultaneously, because the effect of above-mentioned multinomial design and structure for the whole air supply volume of fan is showing and is promoted. Therefore, if the filter element is applied to an air purification system, the filter element can be selected to have high air resistance, high filtration level and good filtration effect under the same condition. This will provide a more effective and healthier air purification effect and use experience for the user.

Example two:

fig. 6 is a schematic structural view of an upper volute casing of a wind tunnel according to a second embodiment of the fan duct system of the present invention. Fig. 7 is a schematic structural view of an air outlet duct in a second embodiment of the fan duct system of the present invention.

The structure of the present embodiment is substantially the same as that of the first embodiment, except that: in the first embodiment, the volute casing 30 is a separate component. In specific implementation, the scheme can be properly adjusted according to the characteristics and requirements of different products.

Therefore, as shown in fig. 6 and 7, the upper scroll casing 70 of the present embodiment is not provided as a separate component, but is integrally formed with a product casing 71. In this application, the volute casing 70 and the product casing 71 are integrally formed, which has the advantages of better sealing performance, minimized air flow loss from the gap, and improved air volume.

In one embodiment, the outlet duct 60 and the volute casing 30 are an integral component. In the specific implementation process, the air outlet duct 60 may be combined with other components of the fan and duct system of the present invention through other schemes according to different conditions such as processing, mold, product molding, etc.

Therefore, in this embodiment, the air outlet duct 60 is configured as an independent insert, assembled with the upper casing 70 of the volute duct via the mounting slot of 80a, and combined with other structures, such as the upright 70a in fig. 6, and fixed together through the mounting hole of 80 b.

In addition, the invention also provides an air purifier, which is characterized in that the air purifier adopts the fan air duct system of the embodiment, such as a portable air purifier, a household air purifier or a vehicle-mounted air purifier.

In summary, the fan air duct system and the air purifier comprising the same effectively improve the overall air output of the fan by optimizing the design and structure of the wind wheel and the overall fan formed by matching the wind wheel with the motor. Meanwhile, the energy efficiency of the fan is enhanced by optimizing the technology and the design of the wind wheel and the matched motor, and the service life of the product is prolonged under the same power capacity, so that the aims of saving energy, protecting the environment and improving the use experience of customers are fulfilled.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that these are by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.

Claims

1. A fan air duct system is characterized by comprising a wind wheel, a motor, a volute air duct upper shell and a volute air duct lower shell, wherein the wind wheel is installed in a cavity formed by connecting the volute air duct upper shell and the volute air duct lower shell, and a shaft of the motor penetrates into the volute air duct lower shell and is connected with the wind wheel;

the front side of the wind wheel is uniformly and alternately provided with a plurality of long blades and a plurality of short blades, one side of each long blade and one side of each short blade are vertical surfaces, the other sides of the long blades and the short blades are arc-shaped, the rear ends of the long blades are fixed at the positions close to the outer edges of the wind wheel, and the front ends of the long blades are fixed at the center of the wind wheel;

the long fan blades are in an airfoil shape, the width of each long fan blade is gradually widened along the extension from the front end to the rear end, the rear ends of the long fan blades are narrower than the widest part of the long fan blades, and the rear ends of the long fan blades are wider than the front ends of the long fan blades;

the short fan blades are in a shape of a minor arc, and the middle parts of the short fan blades are wider than the front ends and the rear ends of the short fan blades;

the vertical plane extension lines of the long fan blades and the short fan blades are intersected at the center point of the wind wheel;

the center of wind wheel is equipped with cylindrical boss, the top of boss is the toper, the top of boss is close to outer edge end and is the plane, the preceding tip part of long flabellum is located the plane department of boss.

2. The fan duct system according to claim 1, wherein the length ratio of the long fan blade to the short fan blade is 1;

3. The fan duct system according to claim 1, wherein a concentric hole is formed in the center of the boss, a metal sleeve is installed in the concentric hole, and the motor is fixedly connected with the wind wheel through the sleeve.

4. The fan duct system of claim 1, wherein the reverse side of the boss of the wind wheel is concave; the depth of the concave shape is 0.5-2cm, and the inner diameter of the concave shape is 1-3cm.

5. The fan duct system according to claim 1, wherein a balance rib is provided around the outer edge of the reverse side of the wind wheel; the height ratio of the balance rib to the long fan blade and the short fan blade is 1.35-1.

6. The fan duct system according to claim 1, wherein the volute upper housing has a circular air inlet on a front side and a row of protrusions on a back side, the protrusions being arranged along an edge of the housing of the volute upper housing;

7. The fan duct system according to claim 1, wherein an air outlet duct is disposed outside the volute casing.

8. An air cleaner, characterized in that the air cleaner comprises a fan duct system according to any one of claims 1-7.