Air supply structure and electric water heater

Abstract

The utility model belongs to the technical field of electric water heaters, and discloses an air supply structure and an electric water heater. According to the air supply structure, a first volute tongue flow guide wall is located on the side, close to an air inlet, of a second volute tongue flow guide wall, the first volute tongue flow guide wall is an arc face, and the distance between the first volute tongue flow guide wall and the central axis of a cross-flow wind wheel is R1; the distance between the second volute tongue flow guide wall and the central axis of the cross-flow wind wheel is R2, R1 is smaller than R2, and R2 is gradually increased in the direction from the air outlet to the air inlet; the air supply structure is low in noise in the working process, noise of the electric water heater can be reduced easily, and user experience can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric water heaters, in particular to an air supply structure and an electric water heater. Background Art

[0002] A cross-flow fan is a common ventilation device, and its structure mainly includes an impeller, a volute and a volute tongue; during the operation of the fan, gas flows in radially and then flows out radially, flowing through the fan blades twice, and the generated air flow has the characteristics of large flow rate and uniform transverse direction. The existing cross-flow fan has the defect of relatively large noise. Content of the Utility Model

[0003] One of the technical problems to be solved by the utility model is to provide an air supply structure capable of reducing noise.

[0004] Another technical problem to be solved by the utility model is to provide an electric water heater capable of reducing noise and improving user experience.

[0005] The above first technical problem is solved by the following technical solutions:

[0006] An air supply structure, including an air supply housing and a cross-flow impeller. The air supply housing has an air supply channel, and both ends of the air supply channel respectively form an air inlet and an air outlet. The cross-flow impeller is rotatably arranged in the air supply channel;

[0007] The upper inner wall of the air supply channel is formed with a first volute tongue guide wall and a second volute tongue guide wall both extending along the circumferential direction of the cross-flow impeller. The first volute tongue guide wall is located on the side of the second volute tongue guide wall close to the air inlet;

[0008] The first volute tongue guide wall is an arc surface with a distance of R1 from the central axis of the cross-flow impeller. The distance between the second volute tongue guide wall and the central axis of the cross-flow impeller is R2, and R1 < R2. From the direction of the air outlet to the air inlet, R2 gradually increases.

[0009] The air supply structure of the utility model, compared with the background art, has the beneficial effects as follows:

[0010] The cross-flow impeller rotates. Under the action of the cross-flow impeller, outside air enters through the air inlet and flows leftward through the gap between the cross-flow impeller and the lower inner wall of the air supply channel. Most of the air flow on the air outlet side of the cross-flow impeller directly flows towards the air outlet, and the remaining small part of the air flow flows towards the narrower end of the second gap under the action of the cross-flow impeller. Since the gap between the narrower end of the second gap and the cross-flow impeller is small, the second volute tongue guide wall has a flow-blocking effect; in the direction from the air outlet to the air inlet, R2 gradually increases, and correspondingly, the second gap gradually increases. Part of the air flow on the air outlet side of the cross-flow impeller enters the second gap from the narrower end of the second gap. As the second gap gradually increases, the air flow pressure gradually decreases, which is beneficial to reducing the noise generated by the friction between the air flow and the inner wall of the second gap. Then the air flow hits the blocking surface formed by the connection of the first volute tongue guide wall and the second volute tongue guide wall, causing the air flow to flow reversely and decompose and dissipate at the narrower part of the second gap. Since R1 < R2 and the first volute tongue guide wall is connected to the second volute tongue guide wall at the wider end of the second gap, the difference between R1 and R2 is relatively large, and the flow-blocking effect at the connection position of the first volute tongue guide wall and the second volute tongue guide wall is strong. The remaining small amount of air flow flows towards the air inlet under the action of the first volute tongue guide wall.

[0011] In one embodiment, the extending direction of the first volute tongue guide wall from the end connected to the second volute tongue guide wall to the other end is the rotation direction of the cross-flow impeller;

[0012] The cross-flow impeller includes a wind wheel shaft and a plurality of blades sequentially arranged circumferentially around the wind wheel shaft. Both ends of each blade respectively form a proximal end and a distal end, and the proximal end is closer to the wind wheel shaft than the distal end;

[0013] Among any two adjacent blades distributed in the rotation direction of the cross-flow impeller, the proximal end of the downstream blade is located between the proximal end of the upstream blade and the distal end of the upstream blade.

[0014] In one embodiment, the radial gap between the first volute tongue guide wall and the maximum outer diameter of the cross-flow impeller is d1, and d1 ≤ 3 mm.

[0015] In one embodiment, the minimum radial gap between the second volute tongue guide wall and the maximum outer diameter of the cross-flow impeller is dmin, and the maximum radial gap between the second volute tongue guide wall and the maximum outer diameter of the cross-flow impeller is dmax;

[0016] The ratio of dmax to dmin is less than or equal to 1.5.

[0017] In one embodiment, the arc length along the circumferential direction of the first volute tongue guide wall is L1, and the arc length along the circumferential direction of the second volute tongue guide wall is L2, and L1 > L2.

[0018] In one embodiment, the ratio of L1 to L2 is less than or equal to 1.2.

[0019] In one embodiment, an air supply channel between the cross-flow impeller and the air outlet end face of the air outlet forms an air outlet channel.

[0020] The air outlet channel includes a first air outlet duct. Along the air outlet direction of the first air outlet duct, the cross-sectional area of the first air outlet duct gradually decreases.

[0021] In one embodiment, the air outlet channel further includes a second air outlet duct communicated with the first air outlet duct. Along the extending direction of the air outlet channel, the first air outlet duct is closer to the cross-flow impeller than the second air outlet duct.

[0022] Along the air outlet direction of the second air outlet duct, the cross-sectional area of the second air outlet duct gradually increases.

[0023] In one embodiment, an air outlet guide wall is provided at a position on the inner wall of the lower side of the air supply channel corresponding to the cross-flow impeller. From the cross-flow impeller to the air outlet direction, the radial distance between the air outlet guide wall and the cross-flow impeller gradually increases.

[0024] In one embodiment, the air inlet and the air outlet are located on the radially opposite sides of the cross-flow impeller.

[0025] The above second technical problem is solved by the following technical solution:

[0026] An electric water heater includes a water heater main body and the air supply structure described in any one of the above embodiments. The air supply structure is installed below the water heater main body.

[0027] Compared with the background art, the electric water heater of the present utility model has the following beneficial effects:

[0028] The electric water heater provided by the embodiment of the present utility model includes the above-mentioned air supply structure. The cross-flow fan rotates, and the outside air enters through the air inlet under the action of the cross-flow fan and flows leftward through the gap between the cross-flow fan and the lower inner wall of the air supply channel. Most of the air flow on the air outlet side of the cross-flow fan directly flows to the air outlet, and the remaining small part of the air flow flows to the narrower end of the second gap under the action of the cross-flow fan. Since the gap between the narrower end of the second gap and the cross-flow fan is small, the second volute tongue guide wall has a flow-blocking effect; in the direction from the air outlet to the air inlet, R2 gradually increases, and correspondingly, the second gap gradually increases. Part of the air flow on the air outlet side of the cross-flow fan enters the second gap from the narrower end of the second gap. As the second gap gradually increases, the air flow pressure gradually decreases, which is beneficial to reducing the noise generated by the friction between the air flow and the inner wall of the second gap. Then the air flow hits the blocking surface formed by the connection of the first volute tongue guide wall and the second volute tongue guide wall, causing the air flow to flow reversely and decompose and dissipate at the narrower part of the second gap. Since R1 < R2 and the first volute tongue guide wall is connected to the second volute tongue guide wall at the wider end of the second gap, the difference between R1 and R2 is large, and the flow-blocking effect at the connection position of the first volute tongue guide wall and the second volute tongue guide wall is strong. The remaining small amount of air flow flows to the air inlet under the action of the first volute tongue guide wall. This is beneficial to reducing the noise of the electric water heater and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-section of the air supply structure provided by the embodiment of the present utility model Figure 1 ;

[0030] Figure 2 is a cross-section of the air supply structure provided by the embodiment of the present utility model Figure 2 ;

[0031] Figure 3 is a schematic diagram of the air flow noise simulation of the air supply structure provided by the embodiment of the present utility model;

[0032] Figure 4 is a schematic diagram of the structure of the electric water heater provided by the embodiment of the present utility model.

[0033] In the figure:

[0034] 11. First volute tongue guide wall; 12. Second volute tongue guide wall; 13. First gap; 14. Second gap; 15. Air outlet guide wall; 16. Air inlet guide wall;

[0035] 2. Cross-flow fan; 21. Fan shaft; 22. Blades; 221. Proximal end; 222. Distal end;

[0036] 3. Air inlet grille;

[0037] 100, air supply channel; 110, air outlet channel; 1101, first air outlet duct; 1102, second air outlet duct; 120, air inlet channel; 130, air inlet; 140, air outlet.

[0038] 1000, air supply structure; 2000, water heater main body; Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0040] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present application.

[0041] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "plurality" is two or more.

[0042] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0043] For the convenience of description and understanding, in the embodiments of the present invention, when it is used on the side facing the control panel of the electric water heater, the side of the battery water heater facing the user is the front side, and the side of the battery water heater facing away from the user is the rear side.

[0044] An embodiment of the present utility model provides an air supply structure and an electric water heater. The electric water heater includes the air supply structure, and the air supply structure can selectively provide hot air, or ambient air, or perform sterilization and purification treatment on the air in the bathroom according to user needs, which can improve the environmental quality in the bathroom and enhance the user experience.

[0045] As Figure 1 and Figure 2 shown, the air supply structure includes an air supply housing, a cross-flow impeller 2, and an impeller motor. Among them, the air supply housing is provided with an air supply channel 100, and both ends of the air supply channel 100 form an air inlet 130 and an air outlet 140 respectively.

[0046] The cross-flow impeller 2 is rotatably arranged in the air supply channel 100, so that the air flow in the air supply channel 100 can flow from the air inlet 130 to the air outlet 140; the impeller motor is installed on the air supply housing, and the output shaft of the impeller motor is connected to the cross-flow impeller 2 to drive the cross-flow impeller 2 to rotate.

[0047] In some embodiments, as Figure 1 and Figure 2 shown, the upper inner wall of the air supply channel 100 is formed with a first volute tongue guide wall 11 and a second volute tongue guide wall 12 that both extend along the circumferential direction of the cross-flow impeller 2. The first volute tongue guide wall 11 is located on the side of the second volute tongue guide wall 12 closer to the air inlet 130; the first volute tongue guide wall 11 is an arc surface with a distance of R1 from the central axis of the cross-flow impeller 2, and the distance between the second volute tongue guide wall 12 and the central axis of the cross-flow impeller 2 is R2, R1 < R2, and in the direction from the air outlet 140 to the air inlet 130, R2 gradually increases. Figure 1 and Figure 2 The direction shown by W in

[0048] is the rotation direction of the cross-flow impeller 2.

[0049] For the convenience of description, the gap between the first volute tongue guide wall 11 and the cross-flow impeller 2 is denoted as the first gap 13, and the gap between the second volute tongue guide wall 12 and the cross-flow impeller 2 is denoted as the second gap 14. Figure 1 and Figure 2As shown, the cross-flow impeller 2 rotates clockwise. Under the action of the cross-flow impeller 2, outside air enters through the air inlet 130 and flows leftward through the gap between the cross-flow impeller 2 and the inner wall of the lower side of the air supply channel 100. Most of the air flow on the air outlet side of the cross-flow impeller 2 directly flows towards the air outlet 140, and the remaining small part of the air flow flows towards the narrower end of the second gap 14 under the action of the cross-flow impeller 2. Since the gap between the narrower end of the second gap 14 and the cross-flow impeller 2 is small, the second volute tongue deflector wall 12 has a flow-blocking effect. In the direction from the air outlet 140 to the air inlet 130, R2 gradually increases, and correspondingly, the second gap 14 gradually increases. Part of the air flow on the air outlet side of the cross-flow impeller 2 enters the second gap 14 from the narrower end of the second gap 14. As the second gap 14 gradually increases, the air flow pressure gradually decreases, which is beneficial to reducing the noise generated by the friction between the air flow and the inner wall of the second gap 14. Then the air flow hits the blocking surface formed by the connection of the first volute tongue deflector wall 11 and the second volute tongue deflector wall 12, causing the air flow to flow reversely and decompose and dissipate at the narrower part of the second gap 14. Since R1 < R2 and the first volute tongue deflector wall 11 is connected to the second volute tongue deflector wall 12 at the wider end of the second gap 14, the difference between R1 and R2 is relatively large, and the flow-blocking effect at the connection position of the first volute tongue deflector wall 11 and the second volute tongue deflector wall 12 is strong. The remaining small amount of air flow flows towards the air inlet 130 under the action of the first volute tongue deflector wall 11.

[0050] In some embodiments, the extending direction of the first volute tongue deflector wall 11 from the end connected to the second volute tongue deflector wall 12 to the other end is the rotation direction of the cross-flow impeller 2. The cross-flow impeller 2 includes a wind wheel shaft 21 and a plurality of blades 22 arranged in sequence along the circumferential direction of the wind wheel shaft 21. The two end portions of the blade 22 respectively form a proximal end 221 and a distal end 222, and the proximal end 221 is closer to the wind wheel shaft 21 than the distal end 222.

[0051] Among any two adjacent blades 22 distributed along the rotation direction of the cross-flow impeller 2, the proximal end 221 of the downstream blade 22 is located between the proximal end 221 of the upstream blade 22 and the distal end 222 of the upstream blade 22. In other words, the proximal end 221 and the distal end 222 are alternately distributed along the circumferential direction of the cross-flow impeller 2.

[0052] As Figure 1 shown, the rotation direction of the cross-flow impeller 2 is the clockwise direction. Outside air enters the gap between the cross-flow impeller 2 and the inner wall of the lower side of the air supply channel 100 through the air inlet 130, and then flows towards the side of the cross-flow impeller 2 close to the air outlet 140.

[0053] In some embodiments, such as Figure 1 and Figure 2As shown, the radial gap between the first volute tongue guide wall 11 and the maximum outer diameter of the cross-flow impeller 2 is d1, and d1 ≤ 3 mm. By defining the radial gap d1 ≤ 3 mm, it is beneficial to reduce the air flow rate entering the second gap 14, so that most of the air flow in the first gap 13 is blocked by the blocking surface and flows reversely, and then gradually decomposes and dissipates.

[0054] It should be noted that d1 can be any one of 3 mm, 2.5 mm, 2 mm, 1.5 mm, and 1 mm.

[0055] In some embodiments, such as Figure 1 and Figure 2 As shown, the minimum radial gap between the second volute tongue guide wall 12 and the maximum outer diameter of the cross-flow impeller 2 is dmin, and the maximum radial gap between the second volute tongue guide wall 12 and the maximum outer diameter of the cross-flow impeller 2 is dmax; the ratio of dmax to dmin is less than or equal to 1.5. By defining the ratio of dmax to dmin, it is beneficial to control the air flow direction and reduce the noise generated by the friction between the air flow and the inner wall of the second gap 14.

[0056] It should be noted that the ratio of dmax to dmin can be any value greater than 1 and less than or equal to 1.5. Exemplarily, dmax:dmin = 13:11.

[0057] In some embodiments, such as Figure 1 and Figure 2 As shown, the arc length along the circumferential direction of the cross-flow impeller 2 of the first volute tongue guide wall 11 is L1, and the arc length along the circumferential direction of the cross-flow impeller 2 of the second volute tongue guide wall 12 is L2, L1 > L2, and the ratio of L1 to L2 is less than or equal to 1.2.

[0058] By defining the ratio of L1 to L2, it is beneficial to control the air flow direction and reduce the noise.

[0059] It should be noted that the ratio of L1 to L2 can be any value greater than 1 and less than or equal to 1.2. Exemplarily, L1:L2 = 67:57.

[0060] In some embodiments, such as Figure 1 and Figure 2 As shown, the air supply channel 100 between the cross-flow impeller 2 and the air outlet end face of the air outlet 140 forms an air outlet channel 110; the air outlet channel 110 includes a first air outlet channel 1101, and along the air outlet direction of the first air outlet channel 1101, the cross-sectional area of the first air outlet channel 1101 gradually decreases.

[0061] With such a setting, during the process that the compressed air flow generated by the cross-flow impeller 2 flows from the inlet end of the first air outlet duct 1101 to the air outlet end of the first air outlet duct 1101, the compressed air flow is compressed for the second time, increasing the air outlet pressure of the air outlet 140 and increasing the air volume.

[0062] It should be noted that the air supply passage 100 between the cross-flow impeller 2 and the intake end face of the air inlet 130 forms an air intake passage 120.

[0063] In some embodiments, such as Figure 1 and Figure 2 As shown, the air outlet passage 110 further includes a second air outlet duct 1102 communicating with the first air outlet duct 1101. Along the extension direction of the air outlet passage 110, the first air outlet duct 1101 is closer to the cross-flow impeller 2 than the second air outlet duct 1102; along the air outlet direction of the second air outlet duct 1102, the cross-sectional area of the second air outlet duct 1102 gradually increases.

[0064] The compressed air flow that has been compressed for the second time by the first air outlet duct 1101 radiates to a larger area after entering the second air outlet duct 1102, which is beneficial to dispersing the air flow and increasing the air outlet area; moreover, the second air outlet duct 1102 also has the function of guiding the air flow.

[0065] Exemplarily, the air outlet passage 110 formed by the connection of the first air outlet duct 1101 and the second air outlet duct 1102 is a trumpet-shaped passage with large openings at both ends and a narrow middle.

[0066] In some embodiments, an air outlet guiding wall 15 is provided at the position of the lower inner wall of the air supply passage 100 corresponding to the cross-flow impeller 2. From the direction of the cross-flow impeller 2 to the air outlet 140, the radial distance between the air outlet guiding wall 15 and the cross-flow impeller 2 gradually increases. The air flow generated by the rotation of the cross-flow impeller 2 flows toward the side where the air outlet 140 is located under the guiding action of the air outlet guiding wall 15. Since from the direction of the cross-flow impeller 2 to the air outlet 140, the radial distance between the air outlet guiding wall 15 and the cross-flow impeller 2 gradually increases, the air outlet guiding wall 15 can guide most of the air flow to the air outlet 140, obtaining a larger air outlet volume, and reducing the air flow volume guided by the cross-flow impeller 2 to the second volute tongue guiding wall 12, which is beneficial to reducing noise.

[0067] It should be noted that the radial distance between the air outlet guiding wall 15 and the cross-flow impeller 2 refers to the radial distance between the largest circumscribed circle of the cross-flow impeller 1 and the air outlet guiding wall 15. The lower inner wall of the air supply passage 100 has a volute throat, and the volute throat refers to the point where the radial distance between the lower inner wall of the air supply passage 100 and the cross-flow impeller 1 is the closest. From the direction of the air inlet 130 to the air outlet 140, the air outlet guiding wall 15 is located downstream of the volute throat and the end of the air outlet guiding wall 15 close to the cross-flow impeller 2 is connected to the volute throat.

[0068] In some embodiments, an air inlet guiding wall 16 is provided on the inner wall of the lower side of the air supply channel 100 corresponding to the position of the cross-flow air wheel 2. In the direction from the air inlet 130 to the cross-flow air wheel 2, the radial distance between the air inlet guiding wall 16 and the cross-flow air wheel 2 gradually decreases, so that as much air flow as possible can enter the gap between the cross-flow air wheel 2 and the inner wall of the lower side of the air supply channel 100.

[0069] It should be noted that the radial distance between the air inlet guiding wall 16 and the cross-flow air wheel 2 refers to the radial distance between the maximum circumscribed circle of the cross-flow air wheel 1 and the cross-flow air wheel 2. In the direction from the air inlet 130 to the air outlet 140, the air inlet guiding wall 16 is located upstream of the volute throat and the end of the air inlet guiding wall 16 close to the cross-flow air wheel 2 is connected to the volute throat.

[0070] In some embodiments, as Figure 1 shown, an air inlet grille 3 is provided at the air inlet 130, and the outlet of the air inlet grille 3 is higher than the inlet of the air inlet grille 3. With this setting, it is possible to prevent external shower water from entering the interior of the air supply channel 100.

[0071] As Figure 3 shown, through simulation of the above air supply structure, it is found that the noise at the air outlet 140 is less than 60 decibels, and the noise is relatively small.

[0072] In some embodiments, as Figure 4 shown, an embodiment of the present invention further provides an electric water heater, which includes the above air supply structure 1000 and a water heater main body 2000, and the air supply structure 1000 is installed below the water heater main body 2000. The electric water heater includes the above air supply structure 1000, and the air supply structure 1000 has low noise, which is beneficial to reducing the noise of the electric water heater and improving the user experience.

[0073] In some embodiments, as Figure 1 and Figure 2 shown, the air inlet 130 and the air outlet 140 are respectively located on the radially opposite sides of the cross-flow air wheel 2. Compared with the prior art in which the air inlet and the air outlet are arranged at 90°, with this setting, it is beneficial to reduce the volume of the air supply structure 1000 and the occupied space of the air supply structure 1000. Exemplarily, the air inlet 130 is closer to the cross-flow air wheel 2 than the air outlet 140.

[0074] Exemplarily, as Figure 4 shown, the air inlet 130 is provided on the front side of the water heater main body 2000, and the air outlet 140 is provided on the rear side of the water heater main body 2000.

[0075] In the specific content of the above specific embodiments, each technical feature can be combined arbitrarily without contradiction. For the sake of concise description, not all possible combinations of the above technical features are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as within the scope described in this specification.

[0076] The specific content of the above specific embodiments only expresses several embodiments of the present utility model, and its description is relatively specific and detailed. However, it should not be construed as a limitation on the scope of the patent of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several deformations and improvements can still be made, and these all belong to the protection scope of the present utility model. Therefore, the protection scope of the patent of the present utility model shall be subject to the appended claims.

Claims

1. Air supply structure, characterized in that, It includes a air supply housing and a cross-flow impeller (2). The air supply housing has an air supply passage (100). The two ends of the air supply passage (100) respectively form an air inlet (130) and an air outlet (140). The cross-flow impeller (2) is rotatably arranged in the air supply passage (100); On the upper inner wall of the air supply passage (100), a first volute tongue guide wall (11) and a second volute tongue guide wall (12) are formed, both of which extend along the circumferential direction of the cross-flow impeller (2). The first volute tongue guide wall (11) is located on the side of the second volute tongue guide wall (12) closer to the air inlet (130); The first volute tongue guide wall (11) is an arc surface with a distance of R1 from the central axis of the cross-flow impeller (2). The distance between the second volute tongue guide wall (12) and the central axis of the cross-flow impeller (2) is R2, and R1 < R2. In the direction from the air outlet (140) to the air inlet (130), R2 gradually increases.

2. The air supply structure according to claim 1, wherein The extending direction of the first volute tongue guide wall (11) from one end connecting the second volute tongue guide wall (12) to the other end is the rotation direction of the cross-flow impeller (2); The cross-flow impeller (2) includes a wind wheel shaft (21) and a plurality of blades (22) sequentially arranged along the circumferential direction of the wind wheel shaft (21). The two end portions of the blade (22) respectively form a proximal end (221) and a distal end (222), and the proximal end (221) is closer to the wind wheel shaft (21) than the distal end (222); Among any two adjacent blades (22) distributed along the rotation direction of the cross-flow impeller (2), the proximal end (221) of the downstream blade (22) is located between the proximal end (221) of the upstream blade (22) and the distal end (222) of the upstream blade (22).

3. The air supply structure according to claim 1, characterized in that, The radial clearance between the first volute tongue guide wall (11) and the maximum outer diameter of the cross-flow impeller (2) is d1, and d1 ≤ 3 mm.

4. The air supply structure according to claim 1, wherein, The minimum radial clearance between the second volute tongue guide wall (12) and the maximum outer diameter of the cross-flow impeller (2) is dmin, and the maximum radial clearance between the second volute tongue guide wall (12) and the maximum outer diameter of the cross-flow impeller (2) is dmax; The ratio of dmax to dmin is less than or equal to 1.

5.

5. The air supply structure according to claim 1, wherein The arc length of the first volute tongue guide wall (11) extending along the circumferential direction of the cross-flow impeller (2) is L1, and the arc length of the second volute tongue guide wall (12) extending along the circumferential direction of the cross-flow impeller (2) is L2, and L1 > L2.

6. The air supply structure according to claim 5, characterized in that, The ratio of L1 to L2 is less than or equal to 1.

2.

7. The air supply structure according to claim 1, characterized in that The air supply passage (100) between the cross-flow impeller (2) and the air outlet end face of the air outlet (140) forms an air outlet passage (110); The air outlet passage (110) includes a first air outlet passage (1101). Along the air outlet direction of the first air outlet passage (1101), the cross-sectional area of the first air outlet passage (1101) gradually decreases.

8. The air supply structure according to claim 7, wherein The air outlet channel (110) further includes a second air outlet channel (1102) communicating with the first air outlet channel (1101). Along the extending direction of the air outlet channel (110), the first air outlet channel (1101) is closer to the cross-flow impeller (2) than the second air outlet channel (1102). Along the air outlet direction of the second air outlet channel (1102), the cross-sectional area of the second air outlet channel (1102) gradually increases.

9. The air supply structure according to any one of claims 1 to 8, characterized in that, An air outlet guiding wall (15) is provided on the inner wall of the lower side of the air supply channel (100) corresponding to the position of the cross-flow impeller (2). From the cross-flow impeller (2) to the air outlet (140), the radial distance between the air outlet guiding wall (15) and the cross-flow impeller (2) gradually increases.

10. The air supply structure according to any one of claims 1 to 8, characterized in that, The air inlet (130) and the air outlet (140) are located on the radially opposite sides of the cross-flow impeller (2).

11. Electric water heater, characterized in that, It includes a water heater main body (2000) and the air supply structure (1000) according to any one of claims 1 to 10. The air supply structure (1000) is installed below the water heater main body (2000).

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