Air supply device and fresh air handling unit

Abstract

The utility model provides an air supply device and a fresh air handling unit. The air supply device comprises an air supply shell; and a fan assembly. According to the air supply device and the fresh air handling unit, the fan assembly is arranged in the indoor air supply shell, air in the fresh air pipeline located below the ground is pumped into a room through negative pressure generated by the fan assembly, and the problem that air resistance is increased due to the fact that the length of the fresh air pipeline is increased does not need to be considered; therefore, the fresh air can be supplied to any indoor position according to needs, the pressure and the flow speed of the fresh air entering a room can be guaranteed, the indoor fresh air supply capacity is improved, the air supply amount is guaranteed, meanwhile, the problem that in the prior art, the air supply power can only be increased by increasing outdoor main equipment is solved, and the air supply efficiency is improved. Therefore, the problems of noise increase and energy consumption increase caused by increase of the air supply power of the main equipment are solved, the air supply device and the main equipment unit operate stably, the indoor fresh air supply power is strong, and the user experience is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of air processing equipment, in particular to an air supply device and a fresh air unit. Background Art

[0002] Traditional fresh air equipment cannot be installed normally due to the installation location of the equipment, indoor decoration, etc., such as not allowing holes on beams, no ceiling design, and external wall openings. The use of underground duct air supply can solve the above difficulties. Underground duct air supply is to bury the flat duct under the floor, without the need for lintel openings, easy to lay and install pipes, and the air outlet can be located anywhere in the house.

[0003] In the prior art, the underground duct air supply is usually supplied by blowing air from the main equipment to the underground duct. Due to the thickness of the floor, the underground duct is a flat air duct, and the long ducts laid throughout the house, in order to ensure the effective air supply volume of the branch with the largest air supply resistance, the air supply power of the main equipment is generally increased to ensure the air supply capacity. However, increasing the power capacity of the main equipment will cause the equipment to run too noisy, and the increase in the air supply power of the main equipment will further increase the wind resistance in the duct, resulting in poor air volume increase effect of the duct, which seriously affects the user experience. Utility Model Content

[0004] In order to solve the technical problems in the prior art of increasing the air supply power of the main equipment to increase the air supply volume, resulting in excessive noise, poor air volume increase effect and poor user experience, an air supply device and a fresh air unit are provided in which a fan assembly is arranged on the ground of the fresh air duct indoors to ensure the air supply volume while reducing noise.

[0005] An air supply device, comprising:

[0006] An air supply housing, wherein the air supply housing is disposed on the ground, an air inlet is disposed at the bottom of the air supply housing, an air supply port is disposed at the upper portion of the air supply housing, and the air inlet is communicated with a fresh air duct located below the ground;

[0007] A fan assembly is arranged in the air supply housing, and the fan assembly is located between the air inlet and the air supply outlet.

[0008] The fan assembly comprises:

[0009] An induced draft fan, the induced draft fan is disposed in the air supply housing, and an air inlet end of the induced draft fan is connected to the air inlet;

[0010] An air supply fan, the air supply fan is arranged in the air supply housing, and the air supply fan is located above the air outlet end of the induced draft fan;

[0011] The gas at the air inlet passes through the induced draft fan and the supply air fan in sequence and then reaches the supply air outlet.

[0012] A pressurized air duct is arranged in the air supply housing, the induced draft fan is arranged in the pressurized air duct, the air inlet end of the pressurized air duct is connected with the air inlet, and the air outlet end of the pressurized air duct is connected with the air supply fan.

[0013] Along the direction from the air inlet to the air supply fan, the flow area of ​​the boost air duct first increases and then decreases; and / or, along the direction from the induced draft fan to the air supply fan, the flow area of ​​the boost air duct gradually decreases; and / or, along the direction from the air inlet to the induced draft fan, the flow area of ​​the boost air duct gradually increases.

[0014] The shape of the boost air duct is spherical.

[0015] An air supply duct is formed between the side wall of the air supply fan and the inner wall of the air supply shell, an air supply fan air inlet is arranged at the bottom of the air supply fan, the air supply fan air inlet is connected with the induced draft fan, and an air supply fan air outlet is arranged on the side wall of the air supply fan, the air supply fan air outlet and the air supply outlet are both connected with the air supply duct.

[0016] The cross section of the air supply duct is annular, and the central axis of the annular shape is colinear with the central axis of the air supply fan.

[0017] The air supply device further comprises a filtering structure, wherein the filtering structure is arranged in the air supply duct, and the filtering structure is located between the air outlet of the air supply fan and the air supply outlet.

[0018] The filtering structure comprises an annular filter screen and a sealing plate. The annular filter screen surrounds the circumference of the air supply fan, and the sealing plate is arranged at the end of the annular filter screen close to the air supply port.

[0019] The air supply device further comprises a sealing structure, wherein the sealing structure is arranged in the air supply duct, and the sealing structure is located between the air supply fan and the induced draft fan.

[0020] The air supply device also includes an air guide cover, the air supply port is arranged on the top surface of the air supply shell, the air guide cover is arranged at the air supply port, and the air guide cover can make the airflow of the air supply port flow in the horizontal direction.

[0021] The thickness of the air guide cover gradually increases from the edge of the air supply port to the center of the air supply port.

[0022] The air supply fan and the induced air fan are coaxially arranged.

[0023] The air supply device also includes a driving mechanism, which is arranged in the air supply housing and located between the air supply fan and the induced draft fan. The air supply fan and the induced draft fan are both connected to the driving mechanism.

[0024] A fresh air unit comprises the above-mentioned air supply device.

[0025] The air supply device and fresh air unit provided by the utility model arrange a fan assembly in an indoor air supply shell, and utilize the negative pressure generated by the fan assembly to pump the gas in the fresh air duct below the ground into the room. There is no need to consider the problem of increased wind resistance caused by the increase in the length of the fresh air duct, thereby being able to deliver fresh air to any position in the room as needed, and can also ensure the pressure and flow rate of the fresh air entering the room, thereby improving the ability to supply fresh air to the room, ensuring the air supply volume, and improving the user's comfort. At the same time, it also overcomes the problem in the prior art that the air supply power of the outdoor main equipment can only be increased, thereby reducing the problems of increased noise and increased energy consumption caused by the increased air supply power of the main equipment. The air supply device and the main equipment unit operate smoothly, and the indoor fresh air supply power is strong, further improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the structure of the air supply device provided in the embodiment of the utility model;

[0027] Figure 2 Another structural schematic diagram of the air supply device provided by the embodiment of the utility model;

[0028] Figure 3 A cross-sectional view of an air supply device provided in an embodiment of the utility model;

[0029] Figure 4 Another cross-sectional view of the air supply device provided by the embodiment of the utility model;

[0030] In the figure:

[0031] 1. Air supply housing; 11. Air inlet; 12. Air supply outlet; 2. Fresh air duct; 31. Induced draft fan; 32. Air supply fan; 13. Pressurized air duct; 14. Air supply duct; 321. Air supply fan inlet; 322. Air supply fan outlet; 41. Annular filter; 42. Closing plate; 5. Sealing structure; 6. Air guide hood; 7. Driving mechanism. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0033] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "setting", and "connection" 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 direct connection, an indirect connection through an intermediate medium, or the internal connection of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the prior art, underground duct air supply is often supplied by blowing air from the main equipment to the underground duct. Due to the thickness of the floor, the underground duct is a flat air duct, and the long length of the duct laid throughout the house, in order to ensure the effective air supply of the branch with the largest air supply resistance at the farthest distance, the air supply power of the main equipment is generally increased to ensure the air supply capacity. However, increasing the power capacity of the main equipment will cause the problem of excessive noise during equipment operation, and the increase in the air supply power of the main equipment will further increase the wind resistance in the duct, resulting in poor air volume increase in the duct, which seriously affects the user experience. To this end, the present application provides a method such as Figures 1 to 4 The air supply device shown includes: an air supply shell 1, which is arranged on the ground, and an air inlet 11 is arranged at the bottom of the air supply shell 1, and an air supply outlet 12 is arranged at the upper part of the air supply shell 1, and the air inlet 11 is connected to the fresh air duct 2 located below the ground; a fan assembly, which is arranged in the air supply shell 1, and the fan assembly is located between the air inlet 11 and the air supply outlet 12. By setting a fan assembly in the indoor air supply housing 1, the negative pressure generated by the fan assembly is used to pump the gas in the fresh air duct below the ground into the room, without considering the problem of increased wind resistance caused by the increase in the length of the fresh air duct, so that the fresh air can be delivered to any position in the room as needed, and the pressure and flow rate of the fresh air entering the room can be guaranteed, thereby improving the ability to supply fresh air to the room, ensuring the air supply volume, and improving the comfort of the user. At the same time, it also overcomes the problem that the existing technology can only increase the air supply power of the main equipment outdoors, thereby reducing the increase in noise and energy consumption caused by the increase in the air supply power of the main equipment. The air supply device and the main equipment unit operate smoothly, and the indoor fresh air supply power is strong, further improving the user experience. It should be noted that the definition of the ground is determined according to the actual setting position of the fresh air duct. When there is a floor, the surface of the floor facing the indoor space can also be positioned as the ground. Figure 3 and Figure 4 The curve where the arrow is located is the flow path of the fresh air.

[0038] As an embodiment, the fan assembly includes: an induced draft fan 31, which is arranged in the air supply shell 1, and the air inlet end of the induced draft fan 31 is connected to the air inlet 11; an air supply fan 32, which is arranged in the air supply shell 1, and the air supply fan 32 is located above the air outlet end of the induced draft fan 31; the gas at the air inlet 11 passes through the induced draft fan 31 and the air supply fan 32 in sequence and then reaches the air supply outlet 12. The induced draft fan 31 is used to introduce the fresh air in the fresh air duct 2 into the air supply shell 1. At this time, the induced draft fan 31 can pressurize the fresh air once and send the pressurized fresh air to the supply air fan 32, thereby ensuring the air volume and pressure entering the air supply shell 1. The supply air fan 32 is then used to send the fresh air to the air supply port 12 for air supply. At this time, the supply air fan 32 can pressurize the fresh air for a second time to ensure the air supply speed of the air supply port 12, thereby solving the problem of insufficient power of the fresh air fan for underground air duct air supply in the prior art, increasing the air supply distance of the fresh air, further improving the air supply effect of the air supply device, and improving the user experience.

[0039] The air supply housing 1 is provided with a pressurized air duct 13, the induced draft fan 31 is provided in the pressurized air duct 13, the air inlet end of the pressurized air duct 13 is connected with the air inlet 11, and the air outlet end of the pressurized air duct 13 is connected with the air supply fan 32. The pressurized air duct 13 is used to limit the airflow passing through the induced draft fan 31, so as to ensure that the fresh air sent in by the fresh air pipeline can reliably flow to the air supply fan 32, and at the same time, the pressurized air duct 13 can cooperate with the induced draft fan 31 to realize a pressurization of the fresh air, so as to ensure the air supply air volume and air pressure of the air supply device.

[0040] Specifically, along the direction from the air inlet 11 to the air supply fan 32, the flow area of ​​the supercharging air duct 13 increases first and then decreases. By utilizing the increased flow area of ​​the supercharging air duct 13, the induced draft fan 31 can be given way to facilitate the installation of the induced draft fan 31, the size of the induced draft fan 31 can be increased to improve the air-inducing capacity of the induced draft fan 31, and the impact noise generated during the rotation of the blades of the induced draft fan 31 can be reduced, the noise value of the air supply device can be reduced, and the user experience can be improved; while the reduced flow area of ​​the supercharging air duct 13 can guide the fresh air discharged by the blades of the induced draft fan 31, so that the fresh air can flow smoothly and steadily to the air supply fan 32, and the wind speed and pressure of the fresh air can be further increased by utilizing the gradual reduction of the flow area, thereby improving the supercharging effect of the induced draft fan 31 on the fresh air.

[0041] Alternatively, the flow area of ​​the pressurized air duct 13 gradually decreases from the induced draft fan 31 to the supply air fan 32. The reduction in the flow area of ​​the pressurized air duct 13 can guide the fresh air discharged by the blades of the induced draft fan 31, so that the fresh air can flow smoothly and steadily to the supply air fan 32. The gradual reduction in the flow area can also be used to further increase the wind speed and pressure of the fresh air, thereby improving the pressurization effect of the induced draft fan 31 on the fresh air.

[0042] Alternatively, the flow area of ​​the boost air duct 13 gradually increases along the air inlet 11 to the induced draft fan 31, which can not only make way for the induced draft fan 31 to facilitate the installation of the induced draft fan 31 and increase the size of the induced draft fan 31 to improve the air-inducing capacity of the induced draft fan 31, but also reduce the impact noise generated during the rotation of the blades of the induced draft fan 31, reduce the noise value of the air supply device, and improve the user experience.

[0043] The shape of the boost air duct 13 is spherical, and the induced draft fan 31 is located near the center of the sphere. A platform is formed on the spherical part below the induced draft fan 31 to constitute the air inlet end of the induced draft fan 31, and a platform is formed on the spherical part above the induced draft fan 31 to constitute the air outlet end of the induced draft fan 31, so as to achieve the purpose of first increasing and then reducing the flow area of ​​the boost air duct 13, thereby ensuring the boosting effect of the induced draft fan 31.

[0044] Alternatively, the partial shape of the boost air duct 13 is a spherical table shape, and the induced draft fan 31 is located near the center of the spherical table shape. The lower platform of the spherical table shape constitutes the air inlet end of the induced draft fan 31, and there is a transition air duct between the lower platform of the spherical table shape and the air inlet 11 to ensure that the fresh air at the air inlet 11 can flow to the induced draft fan 31. Similarly, there is a transition air duct between the upper platform of the spherical table shape and the air inlet 321 of the supply air fan to ensure that the fresh air delivered by the induced draft fan 31 can flow to the supply air fan 32, thereby avoiding air leakage in the air supply shell 1 and ensuring the air supply volume of the air supply device.

[0045] Preferably, the induced draft fan 31 is an axial flow fan, the air inlet direction of the axial flow fan points to the air inlet 11, and the air outlet direction of the axial flow fan points to the air inlet 321 of the supply air fan.

[0046] Since fresh air needs to be supplied into the room, and most of the fresh air actually required by users is concentrated at a height below 2m, in order for users to obtain fresh air as quickly as possible, it is necessary to avoid the fresh air flowing vertically upward. An air supply duct 14 is formed between the side wall of the air supply fan 32 and the inner wall of the air supply shell 1, and an air supply fan inlet 321 is provided at the bottom of the air supply fan 32. The air supply fan inlet 321 is connected to the induced draft fan 31, and an air supply fan outlet 322 is provided on the side wall of the air supply fan 32. The air supply fan outlet 322 and the air supply outlet 12 are both connected to the air supply duct 14. At this time, the air supply fan 32 obtains pressurized fresh air from the induced draft fan 31 below it, and then under the action of the air supply fan 32, the fresh air enters from the side of the air supply fan 32 to the air supply duct 14 located between the side wall of the air supply fan 32 and the inner wall of the air supply shell 1, changing the flow direction of the fresh air and reducing the flow rate of the fresh air at the air supply port 12, so that the fresh air can be dispersed at the height required by the user and quickly reach the preset position, thereby improving the user experience.

[0047] The cross-section of the air supply duct 14 is annular, and the central axis of the ring is colinear with the central axis of the air supply fan 32. Fresh air can flow evenly from the side wall of the air supply fan 32 to various positions of the annular air supply duct 14, thereby ensuring that the air volume in each area of ​​the air supply port 12 is basically equal, and the distance that the fresh air disperses in the horizontal direction after flowing out of the air supply port 12 is basically the same, thereby ensuring the uniformity of air supply by the air supply device. Moreover, since the fresh air first enters the annular air supply duct 14, the circulation area of ​​the fresh air will increase. At this time, the flow rate of the fresh air will decrease, and the flow rate of the fresh air at the air supply port 12 is also reduced, so that the air supply device can also achieve the purpose of soft air supply.

[0048] The air supply device further includes a filtering structure, which is disposed in the air supply duct 14 and between the air supply fan outlet 322 and the air supply outlet 12. The filtering structure is used to filter the fresh air, thereby further improving the cleanliness of the fresh air delivered into the room.

[0049] Since the air supply fan 32 discharges air to the side thereof, in order to ensure that the fresh air discharged from the air supply fan 32 is filtered, the filtering structure includes an annular filter 41 and a sealing plate 42, wherein the annular filter 41 surrounds the circumference of the air supply fan 32, and the sealing plate 42 is arranged at the end of the annular filter 41 close to the air supply port 12. The annular filter 41 is used to ensure that the fresh air discharged from the air supply fan 32 is filtered, thereby ensuring the filtering effect of the filtering structure, and the sealing plate 42 is used to limit the flow direction of the fresh air, so that the fresh air discharged from the air supply fan 32 can only flow through the annular filter 41, thereby avoiding the problem that the fresh air flows directly to the air supply port 12 through the top of the annular filter 41 and reduces the cleanliness of the fresh air, thereby improving the user experience.

[0050] Preferably, the air supply fan 32 is a centrifugal fan, and the air inlet 11 of the centrifugal fan is connected to the air outlet end of the boost air duct 13. The fresh air delivered into the boost air duct 13 can be evenly dispersed to the surroundings of the centrifugal fan under the action of the centrifugal fan, that is, it can evenly flow into the annular air supply duct 14, so that the air flow in the air supply duct 14 is uniform, and then the air flow at the air supply port 12 is uniform. At this time, the air flow at the air supply port 12 can be guaranteed, thereby ensuring the air supply effect of the air supply device.

[0051] The air supply device further includes a sealing structure 5, which is disposed in the air supply duct 14 and between the air supply fan 32 and the induced draft fan 31. The sealing structure 5 is used to seal the end of the air supply duct 14 close to the induced draft fan 31, so as to prevent the fresh air discharged by the air supply fan 32 from flowing back to the induced draft fan 31 and causing air volume loss, noise and other problems, thereby ensuring the working reliability of the air supply device.

[0052] In order to further improve the air supply comfort of the air supply device, the air supply device also includes an air guide hood 6, the air supply port 12 is arranged on the top surface of the air supply housing 1, the air guide hood 6 is arranged at the air supply port 12, and the air guide hood 6 can make the airflow of the air supply port 12 flow in the horizontal direction. Since the air supply fan 32 is arranged in the air supply housing 1, the airflow of the air supply duct 14 still has the ability to flow upward when it flows to the air supply port 12, that is, the fresh air will still flow to the high place in the room, and the air guide hood 6 is used to further change the airflow at the air supply port 12, so that all airflows flow horizontally, ensuring that the fresh air can flow to the position required by the user as quickly as possible, thereby improving the user experience, and the air supply fan 32 supplies air to the side wall of the air supply housing 1, which can provide the airflow at the air supply port 12 with the ability to flow in the horizontal direction, and with the cooperation of the air guide hood 6, it can further promote the fresh air to flow in the horizontal direction, thereby improving the air supply effect of the air supply device.

[0053] The thickness of the air guide cover 6 gradually increases from the edge of the air supply port 12 to the center direction of the air supply port 12. By increasing the thickness of the air guide cover 6, the side of the air guide cover 6 facing the air supply port 12 forms a guide surface with an angle with the horizontal direction, thereby guiding the fresh air from the air supply port 12 in the horizontal direction, limiting the flow of the fresh air to the high places in the room, and ensuring that the fresh air can flow to the position required by the user as quickly as possible, thereby improving the user experience. At the same time, since the air guide cover 6 has a large thickness in the middle and a small thickness at the edge, the air guide cover 6 is in a conical shape at this time, and the fresh air from the air supply port 12 can be evenly guided to the surroundings, achieving the purpose of 360° horizontal air outlet of the air supply device, further increasing the air outlet effect of the air supply device, and improving the user experience.

[0054] Optionally, the air supply fan 32 is coaxially arranged with the induced draft fan 31. At this time, the airflow discharged by the induced draft fan 31 can evenly enter the air supply fan 32, thereby ensuring the uniformity of the air outlet of the air supply fan 32 and the uniformity of the air flow of the air supply port 12, and improving the air supply effect of the air supply device.

[0055] The air supply device further includes a driving mechanism 7, which is arranged in the air supply housing 1, and the driving mechanism 7 is located between the air supply fan 32 and the induced draft fan 31, and the air supply fan 32 and the induced draft fan 31 are both connected to the driving mechanism 7. The driving mechanism 7 is arranged between the air supply fan 32 and the induced draft fan 31, so that the driving mechanism 7 can avoid obstruction of the air flow in the air supply housing 1, and most of the air flow discharged by the induced draft fan 31 will flow along the side wall of the supercharged air duct 13. At this time, the air flow in the middle of the supercharged air duct 13 is small, and the driving mechanism 7 can be arranged at this position. The air supply fan 32 is a centrifugal fan, and its air flow will also enter from the edge of the air supply fan air inlet 321 and flow toward the side wall of the air supply fan 32 under the action of the blades of the air supply fan 32. At this time, the driving mechanism 7 will also not obstruct the air flow. Therefore, the driving mechanism 7 is arranged at this position to ensure the air supply reliability of the air supply device.

[0056] Preferably, the driving mechanism 7 is a motor, and the induced draft fan 31 includes fan blades, which are arranged on the driving shaft of the motor. The rotation of the driving shaft can drive the fan blades to rotate, thereby forming an axial flow fan structure to realize gas drive.

[0057] A fresh air unit comprises the above-mentioned air supply device.

[0058] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. An air supply device, characterized in that: include: An air supply housing (1), the air supply housing (1) being arranged on the ground, and an air inlet (11) being arranged at the bottom of the air supply housing (1), an air supply outlet (12) being arranged at the top of the air supply housing (1), and the air inlet (11) being connected to a fresh air duct (2) located below the ground; A fan assembly is arranged in the air supply housing (1), and the fan assembly is located between the air inlet (11) and the air supply outlet (12).

2. The air supply device according to claim 1, characterized in that: The fan assembly comprises: An induced draft fan (31), the induced draft fan (31) being arranged in the air supply housing (1), and an air inlet end of the induced draft fan (31) being in communication with the air inlet (11); An air supply fan (32), the air supply fan (32) being arranged in the air supply housing (1), and the air supply fan (32) being located above the air outlet end of the induced draft fan (31); The gas at the air inlet (11) passes through the induced draft fan (31) and the supply air fan (32) in sequence before reaching the supply air port (12).

3. The air supply device according to claim 2, characterized in that: A pressurized air duct (13) is arranged in the air supply housing (1), the induced draft fan (31) is arranged in the pressurized air duct (13), the air inlet end of the pressurized air duct (13) is connected to the air inlet (11), and the air outlet end of the pressurized air duct (13) is connected to the air supply fan (32).

4. The air supply device according to claim 3, characterized in that: Along the direction from the air inlet (11) to the air supply fan (32), the flow area of ​​the boost air duct (13) first increases and then decreases; and / or, along the direction from the induced draft fan (31) to the air supply fan (32), the flow area of ​​the boost air duct (13) gradually decreases; and / or, along the direction from the air inlet (11) to the induced draft fan (31), the flow area of ​​the boost air duct (13) gradually increases.

5. The air supply device according to claim 3, characterized in that: The shape of the boost air duct (13) is spherical; or, a portion of the shape of the boost air duct (13) is spherical.

6. The air supply device according to claim 2, characterized in that: An air supply duct (14) is formed between the side wall of the air supply fan (32) and the inner wall of the air supply shell (1); an air supply fan air inlet (321) is provided at the bottom of the air supply fan (32); the air supply fan air inlet (321) is connected to the induced draft fan (31); an air supply fan air outlet (322) is provided on the side wall of the air supply fan (32); the air supply fan air outlet (322) and the air supply port (12) are both connected to the air supply duct (14).

7. The air supply device according to claim 6, characterized in that: The cross-section of the air supply duct (14) is annular, and the central axis of the annular shape is colinear with the central axis of the air supply fan (32).

8. The air supply device according to claim 6, characterized in that: The air supply device also includes a filtering structure, which is arranged in the air supply duct (14), and the filtering structure is located between the air outlet (322) of the air supply fan and the air supply outlet (12).

9. The air supply device according to claim 8, characterized in that: The filtering structure comprises an annular filter screen (41) and a sealing plate (42); the annular filter screen (41) surrounds the circumference of the air supply fan (32); and the sealing plate (42) is arranged at the end of the annular filter screen (41) close to the air supply port (12).

10. The air supply device according to claim 6, characterized in that: The air supply device further comprises a sealing structure (5), wherein the sealing structure (5) is arranged in the air supply duct (14), and the sealing structure (5) is located between the air supply fan (32) and the induced air fan (31).

11. The air supply device according to claim 1, characterized in that: The air supply device further comprises an air guide hood (6); the air supply port (12) is arranged on the top surface of the air supply housing (1); the air guide hood (6) is arranged at the air supply port (12), and the air guide hood (6) can make the airflow of the air supply port (12) flow in a horizontal direction.

12. The air supply device according to claim 11, characterized in that: The thickness of the air guide cover (6) gradually increases from the edge of the air supply port (12) to the center of the air supply port (12).

13. The air supply device according to claim 2, characterized in that: The air supply fan (32) and the air induced fan (31) are coaxially arranged.

14. The air supply device according to claim 2, characterized in that: The air supply device further comprises a driving mechanism (7), wherein the driving mechanism (7) is arranged in the air supply housing (1), and the driving mechanism (7) is located between the air supply fan (32) and the induced draft fan (31), and the air supply fan (32) and the induced draft fan (31) are both connected to the driving mechanism (7).

15. A fresh air unit, characterized in that: The invention comprises the air supply device according to any one of claims 1 to 14.

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