A double-layer wind turbine casing structure

Abstract

This invention relates to the field of bathroom heater technology, specifically to a double-layer impeller volute structure for use in bathroom heater devices. It includes: a housing body, a first volute tongue, and a second volute tongue. The horizontal distance between the side of the first volute tongue facing the installation space and the first blade layer (closest to the airflow direction) and the first blade layer is not less than the horizontal distance between the side of the first volute tongue facing away from the airflow direction and the first blade layer; and / or the horizontal distance between the side of the second volute tongue facing the installation space and the second blade layer (closest to the airflow direction) and the second blade layer is not less than the horizontal distance between the side of the second volute tongue facing away from the airflow direction and the second blade layer. By eliminating the unfilled air space between the first volute tongue and the first blade and / or between the second volute tongue and the second blade, vortex zones are avoided between the volute tongue and the impeller, reducing energy loss and high-frequency vibrations generated when airflow flows inside the housing body, thereby increasing the airflow of the bathroom heater device and improving its performance.

Description

Technical Field

[0001] This invention relates to the field of bathroom heater technology, specifically to a double-layer impeller volute structure. Background Technology

[0002] Bathroom heaters serve the dual purpose of supplying and exchanging air. Traditional single-motor bathroom heaters primarily employ a single-layer, bidirectional impeller, coupled with a corresponding air duct. Existing technology includes bathroom heater structures with U-shaped air ducts, such as... Figure 1 As shown, in Figure 1 When the fan wheel rotates clockwise, the bathroom heater is in heating and blowing mode; when the fan wheel rotates counterclockwise, the bathroom heater is in ventilation mode.

[0003] Because the airflow must balance heating and ventilation functions while overcoming system resistance through forward and reverse rotation, the blades of the impeller are generally designed to be nearly perpendicular to the impeller diameter. This results in relatively poor efficiency and performance. To improve impeller efficiency, current technology uses a double-layer impeller (either forward or reverse) to replace a single-layer bidirectional impeller. However, when the double-layer impeller rotates, one layer operates as a forward impeller, while the other operates only as a backward impeller. At the same rotational speed, the backward impeller can only transport a smaller volume of air, failing to fill the entire airflow channel. Because the unfilled portion lacks airflow, the pressure there is lower than in areas with airflow, attracting nearby airflow to fill the gap, and even drawing air back from the outlet, forming a stable vortex zone. This leads to performance loss and aerodynamic noise. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the existing bathroom heater device with positive and negative double-layer impellers will generate a vortex zone inside the shell during operation, causing performance loss, thereby providing a positive and negative double-layer impeller volute structure.

[0005] To solve the above-mentioned technical problems, the present invention provides a double-layer impeller casing structure for use in a bathroom heater device, comprising:

[0006] The shell body has a heating air vent and an air exchange vent on its side. The shell body has an installation space inside for installing a double-layer impeller. The double-layer impeller includes a first blade layer and a second blade layer stacked together. The blades of the first blade layer face opposite directions to the blades of the second blade layer.

[0007] The first volute tongue is located between the heating air inlet and the ventilation inlet. The first volute tongue extends from the side of the shell body where the ventilation inlet is located toward the installation space. The installation positions of the first volute tongue and the first blade layer are correspondingly set.

[0008] The second volute tongue is stacked on top of the first volute tongue, and the installation positions of the second volute tongue and the second blade layer are correspondingly set.

[0009] The horizontal distance between the side of the first volute tongue facing the installation space and the side closest to the air blowing direction of the first blade layer and the first blade layer is not less than the horizontal distance between the side of the first volute tongue facing away from the air blowing direction of the first blade layer and the first blade layer.

[0010] And / or the horizontal distance between the side of the second volute tongue facing the installation space and the side closest to the airflow direction of the second blade layer and the second blade layer is not less than the horizontal distance between the side of the second volute tongue facing away from the airflow direction of the second blade layer and the second blade layer.

[0011] Optionally, the first volute tongue is flush with the mounting position of the first blade layer, and / or the second volute tongue is flush with the mounting position of the second blade layer.

[0012] Optionally, the width of the end of the first volute tongue and / or the second volute tongue facing the mounting space is greater than the width of the other end.

[0013] Optionally, the end of the first volute tongue and / or the second volute tongue facing the mounting space is provided with a concave surface.

[0014] Optionally, a first clearance portion is provided on the side of the first volute tongue facing the air blowing direction of the first blade layer, and the end of the first clearance portion facing the installation space is tilted away from the air blowing direction of the first blade layer.

[0015] Optionally, a second clearance portion is provided on the side of the second volute facing the airflow direction of the second blade layer, and the end of the second clearance portion facing the installation space is tilted away from the airflow direction of the second blade layer.

[0016] Optionally, the corners of the first and / or second volute tongues facing the mounting space are provided with outer rounded corners.

[0017] Optionally, the height of the first volute tongue is not less than the sum of the height of the first blade layer and the vertical height of the first blade layer from the bottom surface of the first volute tongue; the height of the second volute tongue is not less than the height of the second blade layer.

[0018] Optionally, the height of the first volute tongue is no greater than the sum of the height of the first blade layer, the vertical height of the first blade layer from the bottom surface of the first volute tongue, and the thickness of the support frame.

[0019] Optionally, the heating air outlet is located on the side of the shell body parallel to the air blowing direction of the second blade layer.

[0020] Optionally, a heating element is installed at the heating air outlet, and the orientation of the heating air outlet, the air blowing direction of the second blade layer, and the heating element are arranged perpendicularly to each other.

[0021] The technical solution of this invention has the following advantages:

[0022] 1. The present invention provides a double-layer impeller volute structure for use in a bathroom heater device, comprising: a shell body having a heating air outlet and a ventilation outlet on its side, and an installation space inside the shell body for installing a double-layer impeller, the double-layer impeller comprising a first blade layer and a second blade layer stacked together, the blade orientation of the first blade layer being opposite to that of the second blade layer; a first volute tongue disposed between the heating air outlet and the ventilation outlet, the first volute tongue extending from the side of the shell body with the ventilation outlet toward the installation space, the first volute tongue being correspondingly positioned with respect to the installation position of the first blade layer; a second volute tongue stacked with the first volute tongue, the second volute tongue being correspondingly positioned with respect to the installation position of the second blade layer; the horizontal distance between the side of the first volute tongue facing the installation space and the first blade layer near the airflow direction of the first blade layer is not less than the horizontal distance between the side of the first volute tongue facing away from the airflow direction of the first blade layer and the first blade layer; and / or the horizontal distance between the side of the second volute tongue facing the installation space and the second blade layer near the airflow direction of the second blade layer is not less than the horizontal distance between the side of the second volute tongue facing away from the airflow direction of the second blade layer and the second blade layer.

[0023] When used as a bathroom heater / ventilation unit, the volute structure features a double-layered impeller installed within its mounting space. Taking the first blade layer rotating clockwise to blow air into the heating vent and the second blade layer rotating clockwise to blow air into the ventilation vent as an example, when the unit blows hot air, the impellers rotate in both directions. The first blade layer rotates clockwise, and the second blade layer rotates counterclockwise. Air from outside the volute structure is drawn into the volute structure through the ventilation vent and then blown out through the heating vent. Because the horizontal distance between the first volute tongue (facing the first blade) and the first blade gradually decreases or remains constant from the side facing the hot air direction to the other, the space between the first volute tongue and the first blade gradually decreases or remains constant. Airflow enters the space between the first blade and the first volute tongue from the side facing the hot air direction, completely filling this area and eliminating any unfilled space between them. Because the horizontal distance between the end of the second volute tongue facing the second blade and the second blade gradually decreases or remains constant from the side facing the ventilation direction to the other side, the volume of space between the second volute tongue and the second blade without flowing air can be eliminated during ventilation. By eliminating the volume of space without flowing air between the first volute tongue and the first blade and / or between the second volute tongue and the second blade, vortex zones are avoided between the volute tongue and the impeller. This reduces energy loss and high-frequency vibration caused by airflow inside the casing, thereby increasing the airflow during heating and ventilation in the bathroom heater / ventilation unit and improving its performance.

[0024] 2. The double-layer impeller volute structure provided by this invention has a width at one end of the first and / or second volute tongue facing the installation space that is greater than the width at the other end. By widening the side of the first and / or second volute tongue facing the installation space, in conjunction with the first and second clearance portions, the airflow space on the blowing side of the forward-rotating blade layer is greater than the airflow space in the blowing direction of the reverse-rotating blade layer. Since the air volume transported by the forward-rotating blade layer is greater than that transported by the reverse-rotating blade layer, by changing the size of the airflow space, the air velocity in the corresponding airflow channels of the first and second blade layers is matched, allowing the airflow to completely fill the entire space inside the casing and flow along the preset channel inside the casing. This avoids the airflow direction deviating from the axial direction of the preset channel due to different flow velocities during the flow process, thus preventing the formation of vortices in the airflow inside the casing and improving the working performance of the volute structure when used as a bathroom heater device.

[0025] 3. The double-layer impeller casing structure provided by this invention has a first clearance portion on the side of the first volute tongue facing the airflow direction of the first blade layer. The end of the first clearance portion facing the installation space is inclined away from the airflow direction of the first blade layer. When the bathroom heater blows hot air outward, since the first blade layer and the first volute tongue are flush, the first clearance portion inclined away from the airflow direction of the first volute tongue reduces the cross-sectional area of ​​the side of the first volute tongue facing the first blade layer. When the air flows to the first volute tongue under the drive of the first blade layer, the air can directly contact the first clearance portion facing the side of the first volute tongue. Under the guidance of the first clearance portion, the air flows to the heating air outlet, reducing the probability of the air flowing to the first volute tongue being hit by the first volute tongue and reversing direction. At the same time, after setting the first clearance portion, the air flows along the first clearance portion, reducing the volume of the space between the first volute tongue and the first blade layer where there is no flowing air. This can effectively avoid the formation of a vortex zone between the first volute tongue and the first blade layer, allowing the air to flow smoothly in the internal space of the casing.

[0026] 4. The double-layer impeller casing structure provided by this invention has a second clearance portion on the side of the second volute tongue facing the airflow direction of the second blade layer. The end of the second clearance portion facing the installation space is tilted away from the airflow direction of the second blade layer. When the bathroom heater is ventilating, the air flows along the second clearance portion of the second volute tongue under the drive of the second blade layer, and is finally blown out from the ventilation port. This reduces the volume of the space between the second volute tongue and the second blade layer where there is no flowing air, and can effectively avoid the formation of a vortex zone of airflow between the second volute tongue and the second blade layer during the ventilation process.

[0027] 5. The double-layer impeller casing structure provided by the present invention has an outer rounded corner at the corner of the first and / or second volute tongue facing the installation space. By setting the outer rounded corner, the flushness of the corner and the surface connection of the first and / or second volute tongue is improved, reducing the obstruction of airflow and reducing energy loss during airflow.

[0028] 6. The double-layered impeller casing structure provided by this invention has the following characteristics: the height of the first volute tongue is not less than the sum of the height of the first blade layer and the vertical height of the first blade layer from the bottom surface of the first volute tongue; the height of the second volute tongue is not less than the height of the second blade layer. This ensures that the first and second volute tongues can completely cover the airflow areas of the first and second blade layers in the height direction, reducing radial airflow in the height direction of the first volute tongue within the casing body and reducing energy loss during airflow.

[0029] 7. The double-layer impeller volute structure provided by this invention has a first volute tongue whose height is no greater than the sum of the height of the first blade layer, the vertical height of the first blade layer from the bottom surface of the first volute tongue, and the thickness of the support frame. By limiting the height of the first volute tongue, it is prevented from extending into the air-blowing area of ​​the second blade layer in the height direction, thus avoiding the first volute tongue from affecting the airflow of the second blade layer and improving the airflow and ventilation performance of the volute structure when used as a bathroom heater / ventilation device. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the internal structure of a bathroom heater housing in the prior art.

[0032] Figure 2 This is a schematic diagram of the structure of a bidirectional wind turbine.

[0033] Figure 3 This is a side view of the wind turbine in both directions.

[0034] Figure 4 for Figure 3 A sectional view along the A-A direction.

[0035] Figure 5 for Figure 3 A cross-sectional view along the B-B direction.

[0036] Figure 6 This is a front sectional view of a bathroom heater device provided in an embodiment of the present invention.

[0037] Figure 7 This is a perspective view of a bathroom heater device provided in an embodiment of the present invention.

[0038] Figure 8 This is a schematic diagram of the internal structure of a bathroom heater device provided in an embodiment of the present invention.

[0039] Explanation of reference numerals in the attached drawings: 1. First blade layer; 2. Second blade layer; 3. Support frame; 4. Shell body; 5. Air exchange port; 6. Heating air outlet; 7. First volute tongue; 8. Second volute tongue; 9. First clearance part; 10. Second clearance part; 11. Installation space; 12. PTC electric heating element; 13. Motor; 14. Air collection plate. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Example 1

[0045] like Figures 2 to 8The illustration shows a bathroom heater device provided in this embodiment, which is assembled from a double-layer impeller volute structure, a double-layer impeller, and an air collecting plate 14 fastened to the volute structure. The double-layer impeller volute structure includes a shell body 4, a first volute tongue 7 fixedly disposed inside the shell body 4, and a second volute tongue 8 stacked on top of the first volute tongue 7.

[0046] like Figure 4 As shown, an air vent 5 is provided on the left side of the shell body 4, and a heating air vent 6 is provided on the lower side of the shell body 4. An installation space 11 is provided inside the shell body 4 for installing a double-layer impeller. Figure 2 As shown, the double-layer impeller includes a first blade layer 1 and a second blade layer 2 stacked together. The blades of the first blade layer 1 face opposite directions to those of the second blade layer 2. A first volute 7 is positioned between the heating air inlet 6 and the ventilation inlet 5. The first volute 7 extends from the side of the housing body 4 where the ventilation inlet 5 is located toward the mounting space 11. The first volute 7 is flush with the mounting position of the first blade layer 1. A first clearance portion 9 is provided on the side of the first volute 7 facing the airflow direction of the first blade layer 1. The end of the first clearance portion 9 facing the mounting space 11 is tilted away from the airflow direction of the first blade layer 1. A second volute 8 is stacked with the first volute 7. The second volute 8 is flush with the mounting position of the second blade layer 2. A second clearance portion 10 is provided on the side of the second volute 8 facing the airflow direction of the second blade layer 2. The end of the second clearance portion 10 facing the mounting space 11 is tilted away from the airflow direction of the second blade layer 2.

[0047] The width of the first volute tongue 7 and the second volute tongue 8 at one end facing the mounting space 11 is greater than the width of their other ends. In this embodiment, both the first volute tongue 7 and the second volute tongue 8 are composed of rectangular blocks and trapezoidal blocks connected together. The first clearance portion 9 and the second clearance portion 10 are respectively provided on the trapezoidal blocks of the first volute tongue 7 and the second volute tongue 8. A concave surface is provided at one end of the first volute tongue 7 and the second volute tongue 8 facing the mounting space 11, and an outer rounded corner is provided at the corner of the first volute tongue 7 and the second volute tongue 8 at the end facing the mounting space 11. Specifically, a first concave surface is provided at one end of the first volute tongue 7 facing the mounting space 11, and the horizontal distance between the side of the first concave surface near the first clearance portion 9 and the first blade layer 1 is not less than the horizontal distance between the side of the first concave surface away from the first clearance portion 9 and the first blade layer 1. Figure 5 The image shown is a top view of the internal structure of a bathroom heater / ventilation unit. Figure 5 The second blade layer 2 is located above the first blade layer 1, and the first volute tongue 7 is located below the second volute tongue 8. The projection lines of the first concave surface and the outer rounded corners of the first volute tongue 7 onto the horizontal plane are shown. Figure 5 As shown by the solid line in the middle. Figure 5D11 and D12 are the projection distances on the horizontal plane between the two endpoints of the projection arc of the first concave surface and the outer diameter of the first blade layer 1, respectively, satisfying D11≥D12. The second concave surface is provided at the end of the second volute tongue 8 facing the mounting space 11. The horizontal distance between the side of the second concave surface near the second clearance portion 10 and the second blade layer 2 is not less than the horizontal distance between the side of the second concave surface away from the second clearance portion 10 and the second blade layer 2. For example... Figure 6 The image shown is a bottom view of the internal structure of a bathroom heater / ventilation unit. Figure 6 The first blade layer 1 is located above the second blade layer 2, and the second volute tongue 8 is located below the first volute tongue 7. The projection lines of the second concave surface and the outer rounded corners at the edges of the second volute tongue 8 onto the horizontal plane are as follows: Figure 6 As shown by the solid line in the middle. Figure 6 D21 and D22 are the projected distances on the horizontal plane between the two endpoints of the projection arc of the second concave surface and the outer diameter of the second blade layer 2, respectively, satisfying D21≥D22. Since the horizontal distance between the end of the first volute tongue facing the first blade and the first blade gradually decreases or remains constant from the side facing the hot air blowing direction to the other side, the space between the first volute tongue and the first blade gradually decreases or remains constant. Airflow enters from the side of the first volute tongue facing the hot air blowing direction into the space between the first blade and the first volute tongue, completely filling the area between them and eliminating the unfilled space volume between them. Similarly, since the horizontal distance between the end of the second volute tongue facing the second blade and the second blade gradually decreases or remains constant from the side facing the ventilation blowing direction to the other side, the unfilled space volume between the second volute tongue and the second blade during ventilation can be eliminated.

[0048] The height of the first volute tongue 7 is not less than the sum of the height of the first blade layer 1 and the vertical height of the first blade layer 1 from the bottom surface of the first volute tongue 7; the height of the second volute tongue 8 is not less than the height of the second blade layer 2. The height of the first volute tongue 7 is not greater than the sum of the height of the first blade layer 1, the vertical height of the first blade layer 1 from the bottom surface of the first volute tongue 7, and the thickness of the support frame 3.

[0049] The heating air outlet 6 is located on the side of the shell body 4 parallel to the air blowing direction of the second blade layer 2. Multiple parallel PTC electric heating elements 12 are installed at the heating air outlet 6 as heating elements. In order to improve the heat exchange efficiency between the air and the electric heating elements, the orientation of the heating air outlet 6, the air blowing direction of the second blade layer 2 and the PTC electric heating elements 12 are arranged perpendicularly to each other.

[0050] like Figure 7As shown, the bathroom heater device provided in this embodiment consists of a volute structure, an air collecting plate 14, and a double-layer impeller. The air collecting plate 14 is installed on the shell body 4 of the volute structure. A motor 13 is installed in the installation space 11 of the shell body 4. The double-layer impeller is installed on the motor 13 by means of shaft coupling and placed inside the volute structure.

[0051] when Figure 8 When the double-layer impeller rotates clockwise, the airflow enters the volute structure from the guide ring of the air collecting plate 14. After being powered by the double-layer impeller, the airflow is heated by the PTC electric heating element 12 and then ejected from the heating air outlet 6. When the blades of the double-layer impeller rotate clockwise... Figure 2 When arranged as shown, the first blade layer 1 works as a forward centrifugal impeller, and the second blade layer 2 works as a backward centrifugal impeller.

[0052] when Figure 8 When the double-layered impeller rotates counterclockwise, the airflow enters the volute structure from the guide ring of the air collecting plate 14, is acted upon by the double-layered impeller, and is then ejected from the air exchange port 5. When the blades of the double-layered impeller rotate counterclockwise... Figure 2 When arranged as shown, the first blade layer 1 operates as a backward centrifugal fan, and the second blade layer 2 operates as a forward centrifugal impeller.

[0053] Comparison of test results at a motor speed of 1250 rpm between the original volute structure and the volute structure provided in this embodiment, with both positive and negative double-layer bidirectional impellers installed in the original volute structure and the volute structure provided in this embodiment:

[0054] plan Wind direction and air volume air exchange direction air volume Primitive volute curve <![CDATA[126m 3 / h]]> <![CDATA[158m 3 / h]]> The volute curve of the present invention <![CDATA[134m 3 / h]]> <![CDATA[174m 3 / h]]>

[0055] It is evident that the air volume has increased regardless of the direction of airflow or ventilation.

[0056] By designing the first and second volute tongues as a combination of a cuboid and a trapezoidal block, the width of the first and second volute tongues facing the impeller is greater than the width of the other end. One side of the trapezoidal block is removed as a clearance portion. Rounded corners and concave surfaces are incorporated to create smooth, curved edges on the first and second volute tongues. The first volute tongue, flush with the first blade layer, protrudes towards the air vent and tilts towards the heating air vent along its axial direction. Similarly, the second volute tongue, flush with the second blade layer, protrudes towards the heating air vent and tilts towards the air vent along its axial direction. When the bathroom heater is blowing hot air, air enters the casing from the impeller and flows along the internal channels of the casing under the drive of the double-layered impellers, eventually being blown out from the heating air outlet. At this time, the first blade layer acts as a forward impeller, and the second blade layer acts as a backward impeller. The first volute tongue is tilted towards the side facing the heating air outlet, and the second volute tongue is protruded towards the side facing the heating air outlet. This makes the volume of the airflow channel in the horizontal layer where the first blade layer is located larger than the volume of the airflow channel in the horizontal layer where the second blade layer is located. Since the backward impeller can transport a smaller amount of air, the flow speed of the airflow driven by the first and second blade layers is matched, which can effectively avoid the performance loss caused by the formation of vortex areas in the airflow inside the casing due to the difference in airflow inside the casing during heating and blowing. When the bathroom heater / ventilation unit is in operation, air enters the casing from the impeller and flows along the internal channels of the casing under the drive of the double-layered impellers, eventually being blown out from the ventilation port. At this time, the second blade layer acts as a forward impeller, and the first blade layer acts as a backward impeller. The second volute tongue is tilted towards the ventilation port, and the first volute tongue protrudes towards the ventilation port. This ensures that the volume of the ventilation airflow channel in the horizontal layer containing the second blade layer is larger than that in the horizontal layer containing the first blade layer. Because the backward impeller can only transport a smaller volume of air, the airflow speeds driven by the first and second blade layers can be matched, effectively preventing performance loss caused by the formation of vortex zones within the casing due to differences in airflow volume during ventilation. Using the volute structure provided in this embodiment improves the performance of the first and second blade layers when operating as backward impellers. Furthermore, by eliminating large-scale vortex zones caused by insufficient performance, it significantly reduces noise and eliminates abnormal sounds.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A double-layered impeller casing structure, characterized in that, For use in bathroom heater / ventilation units, including: The shell body (4) has a heating air vent (6) and an air exchange vent (5) on its side. The heating air vent (6) is located on the lower side of the shell body (4). The shell body (4) has an installation space (11) inside for installing a double-layer impeller. The double-layer impeller includes a first blade layer (1) and a second blade layer (2) stacked together. The blade orientation of the first blade layer (1) is opposite to that of the blade orientation of the second blade layer (2). The first volute tongue (7) is disposed between the heating air inlet (6) and the air exchange port (5). The first volute tongue (7) extends from the side of the shell body (4) where the air exchange port (5) is located toward the installation space (11). The first volute tongue (7) is disposed in accordance with the installation position of the first blade layer (1). The second volute tongue (8) is stacked on top of the first volute tongue (7), and the second volute tongue (8) is installed in a position corresponding to the second blade layer (2); The horizontal distance between the side of the first volute tongue (7) facing the installation space (11) and the first blade layer (1) in the air blowing direction is not less than the horizontal distance between the side of the first volute tongue (7) away from the air blowing direction and the first blade layer (1). And / or the horizontal distance between the side of the second volute tongue (8) facing the installation space (11) and the side close to the air blowing direction of the second blade layer (2) is not less than the horizontal distance between the side away from the air blowing direction of the second blade layer (2) and the second blade layer (2). The first volute tongue (7) is provided with a first clearance portion (9) on the side facing the air blowing direction of the first blade layer (1), and the end of the first clearance portion (9) facing the installation space (11) is tilted away from the air blowing direction of the first blade layer (1).

2. The double-layered impeller casing structure according to claim 1, characterized in that, The width of the first volute tongue (7) and / or the second volute tongue (8) facing the mounting space (11) is greater than the width of its other end.

3. The double-layered impeller casing structure according to claim 2, characterized in that, The first volute tongue (7) and / or the second volute tongue (8) have a concave surface at one end facing the mounting space (11).

4. The double-layered impeller casing structure according to any one of claims 1 to 3, characterized in that, The second volute tongue (8) is provided with a second clearance portion (10) on the side facing the air blowing direction of the second blade layer (2), and the end of the second clearance portion (10) facing the installation space (11) is tilted away from the air blowing direction of the second blade layer (2).

5. The double-layered impeller casing structure according to any one of claims 1 to 3, characterized in that, The first volute tongue (7) and / or the second volute tongue (8) are provided with an outer rounded corner at the end facing the mounting space (11).

6. The double-layered impeller casing structure according to any one of claims 1 to 3, characterized in that, The height of the first volute tongue (7) is not less than the sum of the height of the first blade layer (1) and the vertical height of the first blade layer (1) from the bottom surface of the first volute tongue (7); the height of the second volute tongue (8) is not less than the height of the second blade layer (2).

7. The double-layered wind turbine casing structure according to claim 6, wherein the first blade layer (1) and the second blade layer (2) are connected by a support frame (3), characterized in that, The height of the first volute tongue (7) is not greater than the sum of the height of the first blade layer (1), the vertical height of the first blade layer (1) from the bottom surface of the first volute tongue (7), and the thickness of the support frame (3).

8. The double-layered impeller casing structure according to any one of claims 1 to 3, characterized in that, The heating air outlet (6) is located on the shell body (4) on one side parallel to the air blowing direction of the second blade layer (2).

9. The double-layered impeller casing structure according to claim 8, characterized in that, A heating element is installed at the heating air outlet (6), and the orientation of the heating air outlet (6), the blowing direction of the second blade layer (2), and the heating element are arranged perpendicularly to each other.

Images