High-efficiency air shielding fan

Abstract

The invention relates to the technical field of air conditioning, and discloses a high-efficiency air shielding fan which is characterized in that eight blades distributed in a central symmetry manner are fixedly mounted on a second connecting plate, the front side and the rear side of the second connecting plate are each provided with a connecting ring fixedly connected with the blades, and the blades are backwards-bent blades; the front edge, close to the air inlet, of each blade is designed to be in an oval arc shape, the rear edge, close to the rear air plate, of each blade is provided with a beveled corner so as to improve the inflow and outflow efficiency of air, one end of each spiral spring is machined to be in a hook shape and used for being connected with the shielding door, and the other end of each spiral spring is a plane and makes contact with a fixed support in the fan during installation. Negative pressure is formed in the fan, so that external atmospheric pressure pushes the shielding door to compress the spiral spring, the valve is smoothly opened, air enters the fan, and when the negative pressure disappears, elastic force can be provided to push the valve to be closed and keep sealing.

Description

Technical Field

[0001] The invention relates to the technical field of air conditioning, in particular to a high-efficiency air shielding fan. Background Art

[0002] In modern industrial and technological application scenarios, improving the efficiency of air shielding fans has become a key demand. When traditional ventilation equipment is used to handle air treatment tasks in special environments, the efficiency bottleneck is becoming more and more obvious.

[0003] From the perspective of industrial production, for example, in the fields of chemical industry and pharmaceutical industry, the process has extremely high requirements for air cleanliness and airflow stability. Due to the limitations of structural design, the interaction between the impeller and the airflow of traditional fans is not optimized, resulting in a large amount of energy loss in the form of heat energy, turbulent energy, etc. during the air pushing process, and it is impossible to achieve efficient air transportation and shielding. Its internal flow channel is not carefully designed, and the airflow is prone to severe disturbance when entering and exiting the fan and flowing through various components, resulting in pressure loss and reduced efficiency.

[0004] In electronic manufacturing and scientific research environments, precise control of temperature, humidity and air quality depends on efficient air shielding and circulation systems. However, it is difficult for traditional fans to meet air shielding requirements while ensuring efficient operation. The sealing structure and air chamber design are simple, which not only cannot effectively prevent air leakage and external interference, but also consumes too much energy due to additional air resistance. Moreover, the rising energy costs have prompted various industries to seek more energy-saving and efficient equipment. Therefore, it is urgent to invent a high-efficiency air shielding fan to solve the above problems. Summary of the invention

[0005] In view of the fact that the air chamber in the prior art is poorly designed, not only is it unable to effectively prevent air leakage and external interference, but it also consumes too much energy due to additional air resistance, the present invention provides a high-efficiency air shielding fan.

[0006] To achieve the above-mentioned solution, the present invention provides the following technical solutions: a high-efficiency air shielding fan, comprising a casing and an impeller, the casing is a double-layer structure, the casing comprises a first connecting plate, a front wind plate and a rear wind plate, the first connecting plate is spiral-shaped, the first connecting plate is fixedly installed between the front wind plate and the rear wind plate, and a guide plate is fixedly installed between the front wind plate and the rear wind plate, a connecting port is provided on the rear wind plate, an air inlet is provided on the front wind plate, a shielding door is provided between the front wind plate and the impeller, a fixing frame is fixedly installed on the inner side of the air inlet, the middle of the fixing frame is disc-shaped and has a hole, a limit rod is movably connected in the hole, the limit rod is fixedly installed at the center of the shielding door, and a spiral spring sleeved on the outer side of the limit rod is provided between the shielding door and the fixing frame; The impeller includes a second connecting plate, blades and a connecting ring. Eight blades symmetrically distributed in the center are fixedly installed on the second connecting plate. A connecting ring is respectively provided on the front and rear sides of the second connecting plate to fix the blades. The blade shape is a backward curved blade. The leading edge of the blade close to the air inlet adopts an elliptical arc design, and the trailing edge close to the rear wind plate has a bevel angle.

[0007] Furthermore, the outer layer of the shell is made of stainless steel with a thickness of 3-5mm. The shell is surface treated by spraying to form a plastic coating with a thickness of 0.1-0.3mm. The inner layer of the shell is made of aluminum alloy with a thickness of 2-3mm. The inner and outer shells are fixed by welding, and the connecting parts are sealed with sealant.

[0008] Furthermore, an air diffuser is fixedly installed on the outer side of the front wind plate. The air diffuser is trumpet-shaped, with its large opening facing the air inflow direction and its small opening connected to the impeller inlet. The expansion angle of the trumpet mouth is set between 30°-45°, and the length is 0.5-1 times the impeller diameter.

[0009] Furthermore, the guide plate is made of glass fiber reinforced nylon material with a glass fiber content of 30%. The surface of the guide plate is polished and the surface roughness reaches Ra1.2. A guide plate is provided in the middle between the front wind plate and the rear wind plate, and two guide plates are provided between the front wind plate and the rear wind plate near the air outlet. The shape of the guide plate is designed to be arc-shaped according to the airflow guidance requirements, and the arc is adapted to the airflow direction of the air inlet and outlet of the outer shell.

[0010] Furthermore, the shielding door is a plate of the same size as the air inlet, is made of stainless steel and is 5 mm thick. One side of the shielding door is slightly raised and arc-shaped, and the other side edge is processed with an annular groove and is installed with a nitrile rubber sealing ring. The cross-sectional shape of the sealing ring is circular, and the diameter is slightly larger than the groove, and is installed in the groove by interference fit.

[0011] Furthermore, the coil spring is a cylindrical coil spring made of carbon steel, the diameter of the spring steel wire is 3 mm, and in order to improve its corrosion resistance, the surface of the spring is galvanized. The middle diameter of the coil spring is 20 mm, the effective number of turns is 10, and the free height is 50 mm. One end of the coil spring is processed into a hook shape for connecting to the shielding door, and the other end is a flat surface, which contacts the fixed bracket inside the fan during installation.

[0012] Furthermore, when the impeller rotates, the internal air is sucked away, forming a negative pressure inside the fan, so that the external atmospheric pressure pushes the shielding door to compress the coil spring, causing the valve to open and air to enter the fan. When the negative pressure disappears, the coil spring provides elastic force to push the shielding door to close and maintain a seal.

[0013] Furthermore, the diameter of the impeller is determined according to the air volume and air pressure requirements of the fan, and is between 300 and 600 mm. The impeller flow channel adopts a streamlined design, and the flow channel inlet width gradually decreases from the inlet and the height gradually increases, with a change rate of 1 mm reduction for every 10 mm in width and 0.8 mm increase for every 10 mm in height.

[0014] Furthermore, the impeller is made of high-strength aluminum alloy 7075, the second connecting plate is connected to the rotating shaft by an expansion sleeve, the rotating shaft is movably connected to the motor, the rotating shaft is made of 40CrNiMoA alloy steel, the expansion sleeve is made of high-strength alloy steel, and a pair of angular contact ball bearings of model 7010C are installed at the connecting port of the connecting part, which are installed back to back.

[0015] Furthermore, a bracket matching the first connecting plate and the motor is provided below the first connecting plate and the motor respectively, and a shock-absorbing rubber pad is installed between the bracket, the housing and the motor.

[0016] Compared with the prior art, the present invention provides a high-efficiency air shielding fan, which has the following beneficial effects: 1. The high-efficiency air shielding fan has a double-layer shell, which includes a first connecting plate, a front wind plate and a rear wind plate. The outer layer of the shell is made of stainless steel with a thickness of 3-5mm, which has sufficient strength and corrosion resistance to withstand the impact of the external environment and adverse weather conditions. The shell is surface treated with plastic spraying to improve the aesthetics and corrosion resistance of the shell. The plastic spraying can form a plastic coating with a thickness of 0.1-0.3mm on the surface of the shell, which has good insulation and weather resistance, and can also play a certain protective role. The inner layer of the shell is made of aluminum alloy with a thickness of 2-3mm. Aluminum alloy has good thermal conductivity, which is conducive to the dissipation of internal heat. The inner and outer shells are fixed by welding, and the connection parts are sealed with sealant to ensure the sealing of the air chamber and prevent air leakage.

[0017] 2. The high-efficiency air shielding fan has a spiral-shaped first connecting plate, which is fixedly installed between the front wind plate and the rear wind plate, and a guide plate is fixedly installed between the front wind plate and the rear wind plate, and the guide plate is located in the first connecting plate. An air inlet is opened on the front wind plate, and an air diffuser is fixedly installed on the outside of the front wind plate. The air diffuser adopts a trumpet-shaped design, with its large mouth facing the air inflow direction and the small mouth connected to the impeller inlet. The trumpet-shaped air diffuser and the air inlet can gradually accelerate the air when entering the fan, reducing the sudden contraction loss of the airflow. By adjusting the expansion angle and length of the bell mouth, the expansion angle of the bell mouth is set between 30°-45°, and the length is 0.5-1 times the diameter of the impeller, which can effectively improve the air intake efficiency of the fan.

[0018] 3. The guide plate of the high-efficiency air shielding fan is made of glass fiber reinforced nylon material with a glass fiber content of 30%, which makes the guide plate have high strength and rigidity and light weight. The surface of the guide plate is polished with a surface roughness of Ra1.2 to reduce the friction resistance of the airflow on its surface. There is one guide plate in the middle between the front wind plate and the rear wind plate, and two guide plates are provided between the front wind plate and the rear wind plate near the air outlet. The shape of the guide plate is designed to be arc-shaped according to the airflow guidance requirements, and the arc is adapted to the airflow direction of the shell inlet and outlet, which is convenient for guiding the airflow to flow smoothly and improve the overall efficiency of the fan.

[0019] 4. For this high-efficiency air shielding fan, one end of the coil spring is processed into a hook shape for connecting to the shielding door, and the other end is a flat surface, which contacts the fixed bracket inside the fan during installation. When the impeller rotates, the internal air will be drawn out, forming a negative pressure inside the fan. The external atmospheric pressure then pushes the shielding door to compress the coil spring, allowing the valve to open smoothly and air to enter the fan. When the negative pressure disappears, it can provide elastic force to push the valve to close and maintain a seal.

[0020] 5. This high-efficiency air shielded fan has a shield door between the front wind plate and the impeller. The shield door is a plate of the same size as the air inlet and 5mm thick. One side of the shield door is slightly raised and arc-shaped to reduce the resistance when air enters. The other side edge is processed with an annular groove for installing a nitrile rubber sealing ring. The cross-sectional shape of the sealing ring is circular, and the diameter is slightly larger than the groove. It is installed in the groove through interference fit to ensure reliable sealing. The shield door is made of stainless steel, which has good corrosion resistance and certain strength.

[0021] 6. The high-efficiency air shielding fan has eight blades fixedly mounted on the second connecting plate and distributed symmetrically with the center. A connecting ring is provided on the front and rear sides of the second connecting plate to fix the blades. The blades are backward curved. The leading edge of the blades near the air inlet adopts an elliptical arc design, and the trailing edge near the rear wind plate has a bevel angle to improve the inlet and outlet efficiency of the air. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the main structure of the present invention; Figure 2 It is a schematic diagram of the side structure of the main body of the present invention; Figure 3 is a schematic diagram of the internal structure of the first connecting plate in the present invention; Figure 4 It is a schematic diagram of the structure of the front wind plate and the rear wind plate in the present invention; Figure 5 It is a structural schematic diagram of the shielding door in the present invention; Figure 6It is a schematic diagram of the structure of the spiral spring in the present invention; Figure 7 It is a structural schematic diagram of the impeller in the present invention; Figure 8 It is a structural schematic diagram of the guide plate in the present invention; Fig. 9 It is a structural schematic diagram of the cross section of the impeller in the present invention.

[0023] In the figure: 10, first connecting plate; 11, front wind plate; 12, rear wind plate; 13, air inlet; 14, air diffuser; 15, bracket; 16, guide plate; 17, air outlet; 18, connecting port; 20, shielding door; 21, coil spring; 22, fixing bracket; 23, limit rod; 30, motor; 31, rotating shaft; 32, second connecting plate; 33, blades; 34, connecting ring. DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in an exemplary manner in conjunction with the accompanying drawings.

[0025] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0027] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the present invention, unless otherwise clearly specified and limited, the first feature "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the descriptions with reference to the terms "one scheme", "some schemes", "examples", "specific examples" or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the scheme or example are included in at least one scheme or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same scheme or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more schemes or examples.

[0029] See also Figures 1 to 9 The present invention proposes a high-efficiency air shielding fan. When in use, the motor 30 is started, the motor 30 will drive the rotating shaft 31 to rotate, and the rotating shaft 31 will drive the second connecting plate 32 fixedly connected to the rotating shaft 31 to rotate. Eight blades 33 distributed in a central symmetrical manner are fixedly installed on the second connecting plate 32. A connecting ring 34 is respectively provided on the front and rear sides of the second connecting plate 32 to be fixedly connected to the blade 33. The blade 33 is in the shape of a backward curved blade 33. The leading edge of the blade 33 close to the air inlet 13 adopts an elliptical arc design, and the trailing edge close to the rear wind plate 12 has a bevel angle to improve the air inlet and outlet flow efficiency. The diameter of the impeller is determined according to the air volume and air pressure requirements of the fan, and is generally between 300-600mm.

[0030] The impeller flow channel adopts a streamlined design. The flow channel inlet width gradually decreases from the inlet, and the height gradually increases. The change rate is 1mm reduction for every 10mm of width and 0.8mm increase for every 10mm of height, so as to optimize the airflow pre-compression effect and thus improve the air intake efficiency.

[0031] The impeller is made of high-strength aluminum alloy 7075 and connected to the shaft 31 by an expansion sleeve. The shaft 31 is made of 40CrNiMoA alloy steel. After tempering and surface quenching, the hardness reaches HRC45-50 to improve wear resistance. The expansion sleeve is made of high-strength alloy steel. The matching tolerance between it and the shaft 31 and the impeller is accurately calculated to ensure reliable connection and concentricity within 0.01mm. A pair of angular contact ball bearings, model 7010C, are installed at the connection part, that is, the connection port 18 opened on the rear wind plate 12. They are installed back to back and can withstand radial and axial loads at the same time, ensuring the stability of the shaft during high-speed rotation and reducing vibration and axial movement.

[0032] The shell is a double-layer structure, and includes a first connecting plate 10, a front wind plate 11 and a rear wind plate 12. The outer layer of the shell is made of stainless steel with a thickness of 3-5mm, which has sufficient strength and corrosion resistance and can withstand the impact of the external environment and adverse weather conditions. The shell is surface treated with spraying to improve the aesthetics and corrosion resistance of the shell. The spraying can form a plastic coating with a thickness of 0.1-0.3mm on the surface of the shell, which has good insulation and weather resistance, and can also play a certain protective role. The inner layer of the shell is made of aluminum alloy with a thickness of 2-3mm. Aluminum alloy has good thermal conductivity and is conducive to the dissipation of internal heat. The inner and outer shells are fixed by welding, and the connection parts are sealed with sealant to ensure the sealing of the air chamber and prevent air leakage.

[0033] The first connecting plate 10 is spiral-shaped, and the first connecting plate 10 is fixedly installed between the front wind plate 11 and the rear wind plate 12, and a guide plate 16 is fixedly installed between the front wind plate 11 and the rear wind plate 12. An air inlet 13 is provided on the front wind plate 11, and an air diffuser 14 is fixedly installed on the outer side of the front wind plate 11. The air diffuser 14 adopts a trumpet-shaped design, with its large mouth facing the air inflow direction, and the small mouth connected to the impeller inlet. The trumpet-shaped air diffuser 14 and the air inlet 13 can gradually accelerate the air when entering the fan, reducing the sudden contraction loss of the airflow. By adjusting the expansion angle and length of the bell mouth, the expansion angle of the bell mouth is set between 30°-45°, and the length is 0.5-1 times the diameter of the impeller, which can effectively improve the air intake efficiency of the fan.

[0034] The guide plate 16 is made of glass fiber reinforced nylon material with a glass fiber content of 30%, which makes the guide plate 16 have high strength and rigidity and light weight. The surface of the guide plate 16 is polished and the surface roughness reaches Ra1.2, reducing the friction resistance of the airflow on its surface. The guide plate 16 is provided with one in the middle between the front wind plate 11 and the rear wind plate 12, and two guide plates 16 are provided between the front wind plate 11 and the rear wind plate 12 near the air outlet 17. The shape of the guide plate 16 is designed to be arc-shaped according to the airflow guiding requirements, and the arc is adapted to the airflow direction of the outer shell air inlet 13 and the air outlet 17, so as to guide the airflow to flow smoothly and improve the overall efficiency of the fan.

[0035] A shielding door 20 is provided between the front wind plate 11 and the impeller. The shielding door 20 is a plate of the same size as the air inlet 13 and has a thickness of 5 mm. One side surface of the shielding door 20 is slightly raised and arc-shaped to reduce the resistance when air enters. An annular groove is processed on the edge of the other side for installing a nitrile rubber sealing ring. The cross-sectional shape of the sealing ring is circular, and the diameter is slightly larger than the groove. It is installed in the groove by interference fit to ensure reliable sealing. The shielding door 20 is made of stainless steel, which has good corrosion resistance and certain strength.

[0036] A fixing frame 22 is fixedly installed on the inner side of the air inlet 13. The middle of the fixing frame 22 is disc-shaped and has a hole. A limit rod 23 is movably connected in the hole. The limit rod 23 is fixedly installed at the center of the shielding door 20. A coil spring 21 is provided between the shielding door 20 and the fixing frame 22 and is sleeved on the outside of the limit rod 23. The coil spring 21 is a cylindrical coil spring made of carbon steel. This material has high strength and elastic modulus and can meet the force required for opening and closing the valve. The diameter of the spring steel wire is 3mm. In order to improve its corrosion resistance, the surface of the spring is galvanized. The middle diameter of the coil spring 21 is 20mm, the effective number of turns is 10, and the free height is 50mm. One end of the coil spring 21 is processed into a hook shape for connecting to the shielding door 20, and the other end is a plane, which contacts the fixed bracket 15 inside the fan during installation. When the impeller rotates, the internal air will be sucked away, so that negative pressure is formed inside the fan, so that the external atmospheric pressure pushes the shielding door 20 to compress the coil spring 21, so that the valve can be opened smoothly, and air can enter the fan. When the negative pressure disappears, it can provide elastic force to push the valve to close and keep it sealed.

[0037] A bracket 15 matching the first connecting plate 10 and the motor 30 is respectively provided below the first connecting plate 10 of the housing and the motor 30. A shock-absorbing rubber pad is installed between the bracket 15 and the housing and the motor 30. The rubber pad has good elasticity and shock-absorbing performance, and can effectively absorb and buffer the vibration and impact force generated during the operation of the motor 30, thereby reducing the wear and fatigue damage to the bracket 15, the housing and the motor 30.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency air shielding fan, comprising a housing and an impeller, characterized in that: The housing comprises a first connecting plate (10), a front air plate (11) and a rear air plate (12); the first connecting plate (10) is spiral-shaped and fixedly installed between the front air plate (11) and the rear air plate (12); a guide plate (16) is fixedly installed between the front air plate (11) and the rear air plate (12); a connecting port (18) is provided on the rear air plate (12); an air inlet (13) is provided on the front air plate (11); a shielding door (20) is provided between the front air plate (11) and the impeller; a fixing frame (22) is fixedly installed on the inner side of the air inlet (13); the fixing frame (22) is disc-shaped in the middle and has a hole; a limiting rod (23) is movably connected in the hole; the limiting rod (23) is fixedly installed at the center of the shielding door (20); a spiral spring (21) sleeved on the outer side of the limiting rod (23) is provided between the shielding door (20) and the fixing frame (22); The impeller comprises a second connecting plate (32), blades (33) and a connecting ring (34); eight blades (33) are fixedly mounted on the second connecting plate (32) and are symmetrically distributed in the center; a connecting ring (34) is respectively provided on the front and rear sides of the second connecting plate (32) and is fixedly connected to the blades (33); the blades (33) are in the shape of backward curved blades (33); the leading edge of the blades (33) close to the air inlet (13) is designed in an elliptical arc shape, and the trailing edge close to the rear wind plate (12) has a beveled angle.

2. A high-efficiency air shielding fan according to claim 1, characterized in that: The shell has a double-layer structure. The outer layer of the shell is made of stainless steel with a thickness of 3-5 mm. The shell is surface treated by spraying to form a plastic coating with a thickness of 0.1-0.3 mm. The inner layer of the shell is made of aluminum alloy with a thickness of 2-3 mm. The inner and outer shells are fixed by welding, and the connecting parts are sealed with sealant.

3. A high-efficiency air shielding fan according to claim 1, characterized in that: An air diffuser (14) is fixedly mounted on the outer side of the front air plate (11); the air diffuser (14) is trumpet-shaped, with a large opening facing the air inflow direction and a small opening connected to the impeller inlet; the expansion angle of the trumpet opening is set between 30° and 45°, and the length is 0.5 to 1 times the diameter of the impeller.

4. A high-efficiency air shielding fan according to claim 1, characterized in that: The deflector (16) is made of glass fiber reinforced nylon material with a glass fiber content of 30%. The surface of the deflector (16) is polished and has a surface roughness of Ra1.

2. A deflector (16) is provided in the middle between the front wind plate (11) and the rear wind plate (12). Two deflectors (16) are provided between the front wind plate (11) and the rear wind plate (12) near the air outlet (17). The shape of the deflector (16) is designed to be arc-shaped, and the arc is compatible with the airflow direction of the air inlet (13) and the air outlet (17) of the housing.

5. A high-efficiency air shielding fan according to claim 1, characterized in that: The shielding door (20) is a plate of the same size as the air inlet (13). The shielding door (20) is made of stainless steel and has a thickness of 5 mm. One side of the shielding door (20) is slightly convex and arc-shaped, and the other side edge is processed with an annular groove and is installed with a nitrile rubber sealing ring. The cross-sectional shape of the sealing ring is circular, and the diameter is slightly larger than the groove. The sealing ring is installed in the groove by interference fit.

6. A high-efficiency air shielding fan according to claim 1, characterized in that: The coil spring (21) is a cylindrical coil spring made of carbon steel, the diameter of the spring steel wire is 3 mm, the surface of the spring is galvanized, the mean diameter of the coil spring (21) is 20 mm, the number of effective turns is 10, and the free height is 50 mm. One end of the coil spring (21) is processed into a hook shape for connecting to the shielding door (20), and the other end is a flat surface for contacting with the fixing bracket (15) inside the fan during installation.

7. A high-efficiency air shielding fan according to claim 6, characterized in that: When the impeller rotates, the internal air is sucked away, so that negative pressure is formed inside the fan, and the external atmospheric pressure pushes the shielding door (20) to compress the coil spring (21), so that the valve is opened and air enters the fan. When the negative pressure disappears, the coil spring (21) provides elastic force to push the shielding door (20) to close and maintain the seal.

8. A high-efficiency air shielding fan according to claim 1, characterized in that: The diameter of the impeller is determined according to the air volume and air pressure requirements of the fan, and is between 300 and 600 mm. The impeller flow channel adopts a streamlined design. The flow channel inlet width gradually decreases from the inlet and the height gradually increases. The change rate is 1 mm for every 10 mm of width and 0.8 mm for every 10 mm of height.

9. A high-efficiency air shielding fan according to claim 8, characterized in that: The impeller is made of aluminum alloy 7075, the second connecting plate (32) is connected to the rotating shaft (31) by means of an expansion sleeve, the rotating shaft (31) is movably connected to the motor (30), the rotating shaft (31) is made of 40CrNiMoA alloy steel, the expansion sleeve is made of high-strength alloy steel, and a pair of angular contact ball bearings of model 7010C are installed at the connecting portion connection port (18), and are installed back to back.

10. A high-efficiency air shielding fan according to claim 9, characterized in that: A bracket (15) matching the first connecting plate (10) and the motor (30) is provided below the first connecting plate (10) and the motor (30), respectively, and a shock-absorbing rubber pad is installed between the bracket (15), the housing and the motor (30).

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