An air inlet cover and fresh air device

Abstract

The application provides an air inlet cover and a fresh air device, wherein the air inlet cover is internally provided with a containing cavity, and the air inlet cover further comprises a side wall and a flow guide assembly. The side wall is arranged around the containing cavity, and the side wall is provided with an air inlet opening communicated with the fresh air pipe and the containing cavity, so that the external air can enter the containing cavity through the air inlet opening. In addition, the flow guide assembly is located in the containing cavity and comprises a first rib and a second rib connected at their ends. A first air inlet channel is formed between the first rib and the side wall, and a second air inlet channel is formed between the second rib and the side wall. Meanwhile, the first air inlet channel, the second air inlet channel and the fresh air pipe are connected in a T shape, and the inlet end width of the second air inlet channel is greater than that of the first air inlet channel. In addition, the second air inlet channel and the fresh air pipe are at least partially substantially parallel, so that when the air enters the second air inlet channel, the flow direction of the air is not changed, thereby further improving the air inlet efficiency of the air inlet cover.

Description

Technical Field

[0001] This application relates to the field of household appliance technology, and in particular to an air inlet cover and a fresh air device. Background Technology

[0002] Currently, ordinary air conditioners can only exchange heat and circulate indoor air. When users close doors and windows, the air quality deteriorates over time, leading to a decline in user experience. In contrast, fresh air systems can circulate indoor and outdoor air without opening windows. Therefore, as living standards improve, air conditioners with fresh air systems are becoming increasingly popular with consumers and are gradually becoming standard equipment in the air conditioning industry.

[0003] However, when outside air enters the existing fresh air system, the airflow directly impacts the inner wall of the air inlet hood, causing severe impact and continuous rebound within the cavity. This results in the airflow being continuously consumed, leading to a decrease in air volume, airflow loss, and affecting the ventilation effect of the fresh air system. Summary of the Invention

[0004] This application provides an air inlet hood and a fresh air device to solve the problem of air volume loss caused by existing fresh air devices during air intake.

[0005] In a first aspect, embodiments of this application provide an air inlet shroud, comprising:

[0006] Receiving cavity;

[0007] The side wall surrounds the receiving cavity, and the side wall is also provided with an air inlet that communicates with the fresh air duct and the receiving cavity;

[0008] A flow guiding assembly, located within the receiving cavity, comprising a first rib and a second rib whose ends are connected to each other;

[0009] A first air intake channel is formed between the first rib and the side wall, and a second air intake channel is formed between the second rib and the side wall. The first air intake channel, the second air intake channel, and the fresh air duct are connected in a T-shape, and the second air intake channel is at least partially parallel to the fresh air duct.

[0010] The width of the inlet end of the second air inlet channel is greater than the width of the inlet end of the first air inlet channel.

[0011] Optionally, in one embodiment, the width of the fresh air duct near the receiving cavity is greater than the width of the inlet end of the second air inlet channel, and the second air inlet channel is positioned directly opposite the fresh air duct.

[0012] Optionally, in one embodiment, the projection of the connection point between the first rib and the second rib at the outlet end of the fresh air duct is located inside the fresh air duct.

[0013] Optionally, in one embodiment, the cross-sectional area of ​​the first air inlet channel gradually increases along the airflow direction within the receiving cavity, and / or the cross-sectional area of ​​the second air inlet channel gradually increases along the airflow direction within the receiving cavity.

[0014] Optionally, in one embodiment, a collection cavity is further provided on the side of the receiving cavity away from the air inlet, and the outlet ends of the first air inlet channel and the second air inlet channel are both located towards the collection cavity and are connected to the collection cavity.

[0015] Optionally, in one embodiment, the airflow guiding component further includes a third rib and a fourth rib, one end of the third rib being connected to the second rib and the other end of the third rib being connected to the fourth rib, the fourth rib extending in a direction away from the second air inlet channel, and the sidewall near the fourth rib also having an extension portion, the extension portion being inclined toward the fourth rib.

[0016] Optionally, in one embodiment, the third rib is obliquely connected to the second rib, and the oblique angle between the third rib and the second rib is 160° to 165°.

[0017] Optionally, in one embodiment, the fourth rib is inclined to the third rib, the inclination angle of the fourth rib to the third rib is 45° to 50°, and the length of the fourth rib is 20mm to 22mm.

[0018] Optionally, in one embodiment, the length of the first rib is 35mm to 38mm, the length of the second rib is 45mm to 48mm, and the angle between the first rib and the second rib is 75° to 80°.

[0019] Secondly, embodiments of this application also provide a fresh air device, comprising:

[0020] As described in any of the above-mentioned air intake hoods;

[0021] A filter frame is disposed adjacent to the air inlet hood;

[0022] The first volute, wherein the filter frame is disposed in the first volute;

[0023] The second volute is connected to the first volute.

[0024] A centrifugal impeller is disposed between the first volute and the second volute.

[0025] The air inlet hood provided in this embodiment has a receiving cavity. The air inlet hood also includes a side wall and a flow guiding assembly. The side wall surrounds the receiving cavity and has an air inlet communicating with the fresh air duct and the receiving cavity, allowing outside air to enter the receiving cavity through the air inlet. Furthermore, the flow guiding assembly is located within the receiving cavity and includes a first rib and a second rib connected at their ends. A first air inlet channel is formed between the first rib and the side wall, and a second air inlet channel is formed between the second rib and the side wall. This allows the air at the air inlet to be diverted to both sides of the air inlet, preventing the airflow from directly impacting the inner wall of the cavity when the air inlet hood is opened. The first and second ribs also guide the airflow at the air inlet, thus preventing the airflow entering the receiving cavity from continuously flowing into the cavity. The airflow rebounds within the cavity, causing airflow loss. Simultaneously, the first air intake channel, the second air intake channel, and the fresh air duct are connected in a T-shape, with the inlet width of the second air intake channel being greater than that of the first air intake channel. This allows for the placement of the first and second ribs within the cavity based on the asymmetrical structure of the air intake hood, achieving non-uniform airflow guidance. Most of the airflow is directed to a larger area within the air intake hood, while a smaller portion is directed to a smaller area. Furthermore, the second air intake channel is at least partially parallel to the fresh air duct, ensuring that the airflow direction is not suddenly altered when air enters the second air intake channel. This prevents sudden changes in airflow direction that could lead to airflow loss or insufficient intake, further improving the air intake efficiency of the air intake hood. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0028] Figure 1 This is a schematic diagram of the exploded structure of a fresh air device in the prior art.

[0029] Figure 2 This is a schematic diagram of the overall structure of the air inlet shroud in the prior art.

[0030] Figure 3 This is a schematic diagram of the overall structure of the air inlet shroud provided in an embodiment of this application.

[0031] Figure 4This is a cross-sectional view of the air inlet shroud provided in an embodiment of this application.

[0032] Figure 5 for Figure 4 The diagram shows the dimensions and structure of the air intake shroud's airflow guiding components and extensions.

[0033] Figure 6 This is a schematic diagram of the exploded structure of the fresh air device provided in the embodiments of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] Currently, ordinary air conditioners can only exchange heat and circulate indoor air. When users close doors and windows, the air quality deteriorates over time, leading to a decline in user experience. In contrast, fresh air systems can circulate indoor and outdoor air without opening windows. Therefore, as living standards improve, air conditioners with fresh air systems are becoming increasingly popular with consumers and are gradually becoming standard equipment in the air conditioning industry.

[0036] Please see Figure 1 , Figure 1 This is an exploded structural diagram of a conventional fresh air system. Conventional fresh air systems typically include an air inlet hood 10, a filter frame 20, a first volute 30, a centrifugal impeller 40, and a second volute 50. When a conventional fresh air system circulates indoor and outdoor air, air is drawn in through the air inlet hood 10. Driven by the centrifugal impeller 40, the air entering the air inlet hood 10 passes through the filter frame 20, the first volute 30, the centrifugal impeller 40, and the second volute 50, ultimately drawing fresh outdoor air into the room to improve indoor air quality.

[0037] In addition, please combine Figure 2 , Figure 2 This is a schematic diagram of the overall structure of the air inlet hood in the prior art. In the prior art, after the air enters the air inlet hood 10, the airflow directly impacts the inner wall of the cavity of the air inlet hood 10, causing severe impact and continuous rebound within the cavity. This results in the continuous consumption of air within the cavity, leading to a decrease in air volume and thus airflow loss. In addition, since the air entering the cavity of the fresh air hood 10 irregularly and continuously hits the inner wall of the cavity, vortices are formed within the cavity. The presence of vortices also leads to the continuous consumption of air volume, resulting in airflow loss and affecting the ventilation effect of the fresh air device.

[0038] To address the aforementioned technical issues, this application provides an air inlet hood that can be applied to refrigeration equipment. Please refer to... Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the overall structure of the air inlet shroud provided in an embodiment of this application. Figure 4 This is a cross-sectional view of the air inlet hood provided in this embodiment. The air inlet hood 100 has a receiving cavity 111. The air inlet hood 100 also includes a side wall 112 and a flow guide assembly 120. The side wall 112 surrounds the receiving cavity 111 and has an air inlet 113 communicating with the fresh air duct 130 and the receiving cavity 111, allowing outside air to enter the receiving cavity 111 through the air inlet 113. Furthermore, the flow guide assembly 120 is located within the receiving cavity 111 and includes a first rib 121 and a second rib 122 connected at their ends. A first air inlet channel 1111 is formed between the first rib 121 and the side wall 112, and a second air inlet channel 1112 is formed between the second rib 122 and the side wall 112, allowing air to pass through the first rib 121. The second rib 122 diverts the airflow at the air inlet 113 to both sides of the air inlet 113, avoiding the situation in the prior art where the airflow directly impacts the inner wall of the cavity when the air inlet hood is inlet. At the same time, the air inlet hood 100 provided in this embodiment can also guide the airflow at the air inlet 113 through the first rib 121 and the second rib 122, so as to guide the airflow entering the receiving cavity 111 to the channel between the first rib 121, the second rib 122 and the side wall 112, and finally gather in the receiving cavity 111. This solves the problem in the prior art where the airflow entering the air inlet hood cavity will constantly bounce in the cavity and irregularly hit the inner wall of the cavity to form vortices, ultimately causing airflow loss.

[0039] In addition, such as Figure 4As shown, the first air inlet channel 1111, the second air inlet channel 1112, and the fresh air duct 130 are connected in a T-shape, and the width of the inlet end of the second air inlet channel 1112 is greater than the width of the inlet end of the first air inlet channel 1111. This allows the first rib 121 and the second rib 122 to be positioned within the accommodating cavity 111 according to the existing asymmetrical structure of the air inlet hood, thereby achieving non-uniform wind guidance. This guides most of the wind to the larger area within the air inlet hood 100 and a smaller portion of the wind to the smaller area within the air inlet hood 100. At the same time, the second air inlet channel 1112 is at least partially parallel to the fresh air duct 130, so that when wind enters the second air inlet channel 1112, the wind direction is not suddenly changed, thus avoiding the problem of air volume loss or insufficient air intake caused by sudden changes in wind direction, and further improving the air intake efficiency of the air inlet hood 100. It is understood that the arrangement of the second air inlet channel 1112 and the fresh air duct 130 in this embodiment can be partially or completely parallel, and can be adjusted according to the actual usage.

[0040] Optional, please continue reading Figure 4 In one embodiment, the width of the fresh air duct 130 near the receiving cavity 111 (i.e., the width of the air inlet 113) can be greater than the width of the inlet end of the second air inlet channel 1112. Simultaneously, since the width of the inlet end of the second air inlet channel 1112 is greater than the width of the inlet end of the first air inlet channel 1111, the width of the fresh air duct 130 near the receiving cavity 111 can be greater than both the width of the inlet end of the first air inlet channel 1111 and the width of the inlet end of the second air inlet channel 1112. This allows the air entering the air intake hood 100 from the air intake 113 to be diverted to the first air intake channel 1111 and the second air intake channel 1112. This avoids the problem that the width of the end of the fresh air duct 130 near the receiving cavity 111, the width of the inlet end of the first air intake channel 1111, and the width of the inlet end of the second air intake channel 1112 are equal, which would result in the air at the air intake 113 only flowing to the first air intake channel 1111 or the second air intake channel 1112, thus failing to achieve the purpose of air intake hood diverting the air.

[0041] At the same time, such as Figure 4As shown, in the above embodiment, the second air inlet channel 1112 can be set directly opposite the fresh air duct 130, so that when the air enters the second air inlet channel 1112 from the air inlet 113, the airflow direction will not change, thus avoiding the problem of airflow loss or insufficient airflow caused by the sudden change of airflow direction after the air enters the second air inlet channel 1112. In addition, the projection of the connection point of the first rib 121 and the second rib 122 at the outlet end of the fresh air duct 130 can be located in the pipe body of the fresh air duct 130, so that when air enters from the air inlet 113, the positions of the first rib 121 and the second rib 122 in the receiving cavity 111 can be set according to the asymmetrical structure of the air inlet hood 130 to achieve non-uniform airflow guidance, so that most of the airflow is guided to the larger area inside the air inlet hood 130 and a small part of the airflow is guided to the smaller area inside the air inlet hood 130, thereby making full use of the structure of the air inlet hood 130 to achieve higher airflow efficiency.

[0042] Optional, such as Figure 4 As shown, in one embodiment, the cross-sectional area of ​​the first air inlet channel 1111 gradually increases along the airflow direction within the receiving cavity 111, and the cross-sectional area of ​​the second air inlet channel 1112 also gradually increases along the airflow direction within the receiving cavity 111. This allows the gradually expanding first air inlet channel 1111 and second air inlet channel 1112 to not only achieve a linear guiding effect on the airflow, but also to reduce the impact force of the airflow within the first air inlet channel 1111 and second air inlet channel 1112 through a gradual expansion. This avoids the situation where the impact force of the airflow is too strong and causes airflow loss or eddies after impacting the sidewall.

[0043] Optional, such as Figure 4 As shown, in one embodiment, a collecting cavity 1113 may be provided on the side of the receiving cavity 111 away from the air inlet 113. The collecting cavity 1113 is connected to the first air inlet channel 1111 and the second air inlet channel 1112. The outlet end of the first air inlet channel 1111 and the outlet end of the second air inlet channel 1112 are both arranged facing the collecting cavity 1113, so that the air entering the receiving cavity 111 from the air inlet 113 can flow between the first air inlet channel 1111, the second air inlet channel 1112 and the collecting cavity 1113, and the air flowing through the first air inlet channel 1111 and the second air inlet channel 1112 can finally be collected in the collecting cavity 1113, thereby collecting the air through the collecting cavity 1113.

[0044] Optional, such as Figure 4As shown, in one embodiment, the flow guiding component 120 may further include a third rib 1231 and a fourth rib 1232. The third rib 1231 and the fourth rib 1232 are connected to each other. One end of the third rib 1231 is connected to the second rib 122 to extend the second air inlet channel 1112, and the other end is connected to the fourth rib 1232. The fourth rib 1232 can be extended in a direction away from the second air inlet channel 1112 to guide the air in the second air inlet channel 1112 to the collection cavity 1113.

[0045] In addition, such as Figure 4 As shown, in other embodiments, the sidewall 112 may include a first sidewall 112A and a second sidewall 112B disposed on both sides of the air inlet 113, wherein a first air inlet channel 1111 is formed between the first rib 121 and the first sidewall 112A, and a second air inlet channel 1112 is formed between the second rib 122 and the second sidewall 112B.

[0046] In this embodiment, since the first air inlet channel 1111, the second air inlet channel 1112, and the fresh air duct 130 are connected in a T-shape, and the width of the inlet end of the second air inlet channel 1112 is greater than the width of the inlet end of the first air inlet channel 1111, when air enters the receiving cavity 111 through the air inlet 113, a small portion of the air will flow along the space between the first rib 121 and the first sidewall 112A to the first air inlet channel 1111, and eventually converge in the collection cavity 1113; while the majority of the air will enter the second air inlet channel 1112 along the space between the second rib 122 and the second sidewall 112B. At this time, the second rib 122 will first affect the second air inlet channel 1112. The airflow in the air duct 1112 has a primary guiding effect. When the airflow reaches the third rib 1231, the third rib 1231 can extend the second air inlet duct 1112 and have a secondary guiding effect on the airflow in the second air inlet duct 1112, so as to prevent the airflow from directly impacting the inner wall of the cavity or constantly rebounding in the cavity, causing airflow loss. After the airflow in the second air inlet duct 1112 has flowed through the second air inlet duct 1112, the fourth rib 1232 can be set towards the collecting cavity 1113, so as to guide the air in the second air inlet duct 1112 to the collecting cavity 1113 to achieve airflow convergence.

[0047] It is understood that, in this embodiment, the arrangement of the first air inlet channel 1111 and the second air inlet channel 1112 also reduces the volume of the air duct at the air inlet 113 to increase the rate at which air enters the collection cavity 1113, thereby making the air inlet hood 100 more efficient.

[0048] Optional, such as Figure 4As shown, in one embodiment, the sidewall 112 may also be provided with an extension 114. Specifically, an air outlet 1114 is provided between the second air inlet channel 1112 and the collection cavity 1113. The air outlet 1114 is located on the side of the flow guide assembly 120 away from the air inlet 113. An extension 114 is also provided on the side of the sidewall 112 near the air outlet 1114 (i.e., the connection between the first sidewall 112A and the second sidewall 112B). The extension 114 is inclined toward the air outlet 1114, thereby increasing the rate at which the air in the second air inlet channel 1112 enters the collection cavity 1113 by compressing the air outlet area of ​​the air outlet 1114, thereby further improving the air intake effect of the air inlet hood 100.

[0049] For example, please refer to Figure 4 And see Figure 5 , Figure 5 for Figure 4 The diagram shows the dimensions and structure of the air intake shroud's airflow guiding assembly and extension. In this embodiment, the length of the first rib 121 can be 35mm to 38mm, the length of the second rib 122 can be 45mm to 48mm, the angle between the first rib 121 and the second rib 122 can be 75° to 80°, and the distance from the connection point of the first rib 121 and the second rib 122 to the air intake 113 can be 18mm to 20mm. In this embodiment, the third rib 1231 can be obliquely connected to the second rib 122, and the angle between the third rib 1231 and the second rib 122 can be 160° to 165°. The fourth rib 1232 can be obliquely connected to the third rib 1231, and the angle between the fourth rib 1232 and the third rib 1231 can be 45° to 50°, and the length of the fourth rib 1232 can be 20mm to 22mm.

[0050] In addition, in other embodiments of this application, the length of the extension 114 may be 22mm to 25mm, and the tilt angle of the extension 114 may be 133° to 136°.

[0051] As shown in the experimental data in the table below, compared with the prior art, when the dimensions of each component of the air inlet shroud 100 in this embodiment are within the range mentioned above, its effect of preventing airflow loss during air intake is the most significant. This can further solve the problem that the airflow directly impacts the inner wall of the cavity during air intake, or that the airflow entering the receiving cavity 111 will continuously bounce within the cavity, causing airflow loss, and effectively improve the air intake effect of the air inlet shroud 100.

[0052]

[0053] Optionally, the air inlet shroud 100 may also include a bottom wall. For example, as shown... Figure 3 As shown, the bottom wall is adjacent to the side wall 112, and the side wall 112 can be arranged around the bottom wall to form a receiving cavity 111. The flow guiding component 120 can be vertically arranged on the bottom wall, thereby increasing the contact area between the flow guiding component 120 and the air, so as to achieve a better diversion and guidance effect on the air entering the receiving cavity 111 from the air inlet 113. It can be understood that the bottom wall, the first rib 121, the second rib 122, the third rib 1231 and the fourth rib 1232 in this embodiment can be made by an integral molding process, thereby further improving the rigidity of the flow guiding component 120 within the air inlet shroud 100, so as to achieve a better diversion and guidance effect on the air.

[0054] Furthermore, in this embodiment, one side of the flow guiding component 120 (i.e., the connection between the first rib 121 and the second rib 122) can also be disposed at the air inlet 113, and the height of the flow guiding component 120 can be greater than or equal to the diameter of the air inlet 113. That is, one side of the flow guiding component 120 can be fixed at the air inlet 113, so that when air enters the cavity 111 through the air inlet 113, the airflow can be diverted and guided, further improving the air intake efficiency when the air inlet hood 100 takes in air.

[0055] This application also provides a fresh air device 200, please refer to... Figure 6 , Figure 6 This is an exploded structural diagram of the fresh air device provided in an embodiment of this application. The fresh air device 200 may include the aforementioned air inlet hood 100, as well as conventional components in the prior art such as a filter frame 20, a first volute 30, a centrifugal impeller 40, and a second volute 50. The filter frame 20 is disposed on the first volute 30 and adjacent to the air inlet hood 100, and the first volute 30 is connected to the second volute 50 to form a receiving cavity (not shown). The centrifugal impeller 40 can be disposed within the receiving cavity between the first volute 30 and the second volute 50.

[0056] When the fresh air device 200 in this embodiment achieves indoor and outdoor air circulation, it draws in air through the air inlet hood 100. The air entering the air inlet hood 100, driven by the centrifugal impeller 40, will pass through the filter frame 20, the first volute 30, the centrifugal impeller 40, and the second volute 50, and finally bring the outdoor fresh air into the room. This can increase the amount of fresh air entering the room without losing air volume, so as to further improve the air quality of the indoor environment.

[0057] It is understood that the fresh air device 200 provided in this embodiment can be applied to air-generating equipment such as air conditioners, ducted air conditioners or fans, so as to achieve the circulation of indoor and outdoor air and improve the air quality of the indoor environment while minimizing the airflow loss when the air intake hood 100 takes in air.

[0058] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0059] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0060] The air inlet hood and fresh air device provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An air inlet shroud (100), characterized in that, include: Receiving cavity (111); Side wall (112), the side wall (112) surrounds the receiving cavity (111), and the side wall (112) is also provided with an air inlet (113) communicating with the fresh air duct (130) and the receiving cavity (111). A flow guiding assembly (120) is located within the receiving cavity (111), and the flow guiding assembly (120) includes a first rib (121) and a second rib (122) whose ends are connected to each other. A first air inlet channel (1111) is formed between the first rib (121) and the side wall (112), and a second air inlet channel (1112) is formed between the second rib (122) and the side wall (112). The first air inlet channel (1111), the second air inlet channel (1112), and the fresh air duct (130) are connected in a T-shape, and the second air inlet channel (1112) is at least partially parallel to the fresh air duct (130). The inlet width of the second air inlet channel (1112) is greater than the inlet width of the first air inlet channel (1111); The airflow guiding assembly (120) further includes a third rib (1231) and a fourth rib (1232). One end of the third rib (1231) is connected to the second rib (122), and the other end of the third rib (1231) is connected to the fourth rib (1232). The fourth rib (1232) extends in a direction away from the second air inlet channel (1112). An extension (114) is also provided on the side of the sidewall (112) near the fourth rib (1232). The extension is inclined toward the fourth rib (1232).

2. The air inlet shroud (100) according to claim 1, characterized in that, The width of the fresh air duct (130) near the receiving cavity (111) is greater than the width of the inlet end of the second air inlet channel (1112), and the second air inlet channel (1112) is positioned directly opposite the fresh air duct (130).

3. The air inlet shroud (100) according to claim 1, characterized in that, The projection of the connection point of the first rib (121) and the second rib (122) at the outlet end of the fresh air duct (130) is located inside the duct of the fresh air duct (130).

4. The air inlet shroud (100) according to claim 1, characterized in that, The cross-sectional area of ​​the first air inlet channel (1111) gradually increases along the airflow direction within the receiving cavity (111), and / or the cross-sectional area of ​​the second air inlet channel (1112) gradually increases along the airflow direction within the receiving cavity (111).

5. The air inlet shroud (100) according to claim 1, characterized in that, A collection cavity (1113) is also provided on the side of the receiving cavity (111) away from the air inlet (113). The outlet end of the first air inlet channel (1111) and the outlet end of the second air inlet channel (1112) are both located towards the collection cavity (1113) and are both connected to the collection cavity (1113).

6. The air inlet shroud (100) according to claim 1, characterized in that, The third rib (1231) is inclined to the second rib (122), and the inclination angle of the third rib (1231) to the second rib (122) is 160°~165°.

7. The air inlet shroud (100) according to claim 1, characterized in that, The fourth rib (1232) is inclined to the third rib (1231), the inclination angle of the fourth rib (1232) to the third rib (1231) is 45°~50°, and the length of the fourth rib (1232) is 20mm~22mm.

8. The air inlet shroud (100) according to claim 1, characterized in that, The length of the first rib (121) is 35mm~38mm, the length of the second rib (122) is 45mm~48mm, and the angle between the first rib (121) and the second rib (122) is 75°~80°.

9. A fresh air device, characterized in that, include: The air inlet shroud as described in any one of claims 1-8; A filter frame is disposed adjacent to the air inlet hood; The first volute, wherein the filter frame is disposed in the first volute; The second volute is connected to the first volute. A centrifugal impeller is disposed between the first volute and the second volute.

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