CN111810445A - Centrifugal fan casing, centrifugal fan and clothes dryer - Google Patents

Abstract

The invention belongs to the technical field of fans, and aims to solve the problem that airflow disturbances easily occur in the air ducts of the existing centrifugal fans, thereby affecting the working efficiency of the centrifugal fans. To this end, the present invention provides a casing of a centrifugal fan, a centrifugal fan and a clothes dryer, wherein a layered structure is arranged in the air duct of the casing, and the layered structure is arranged to be able to separate at least a part of the air duct into at least two The width of the wind layer near the strong wind side is greater than the width of the wind layer near the weak wind side. By setting a layered structure in the air duct, the air duct is divided into at least two wind layers, and the width of the wind layer near the strong wind end is larger than that of the wind layer near the weak wind end, that is, the wind layer at the weak wind end is adjusted by the layered structure. The width of the air duct at the weak wind end matches the air flow at the weak wind end, so as to avoid the situation that the air duct cannot be filled with air flow, and it can avoid the turbulent air flow in the air duct, and avoid affecting the centrifugal fan. work efficiency.

Description

Centrifugal fan casing, centrifugal fan and clothes dryer

technical field

The invention belongs to the technical field of fans, and specifically provides a casing of a centrifugal fan, a centrifugal fan and a clothes dryer.

Background technique

The centrifugal fan is based on the principle of converting kinetic energy into potential energy, using a high-speed rotating impeller to accelerate the gas, then decelerate and change the flow direction, so that the kinetic energy is converted into potential energy (pressure). Centrifugal fans are widely used in ventilation, dust removal and cooling in factories, mines, tunnels, cooling towers, vehicles, ships and buildings; ventilation and induced draft in boilers and industrial furnaces; cooling and air conditioning in air conditioning equipment and household appliances. Ventilation; drying and selection of grain; air source of wind tunnel and inflation and propulsion of hovercraft, etc.

Taking a clothes dryer as an example, the fan on the existing clothes dryer generally adopts a centrifugal fan. The centrifugal fan includes a driving motor, a casing and an impeller arranged in the casing. The driving motor can drive the impeller to rotate at high speed to accelerate the gas, and the gas is driven by One end of the casing enters and flows to the other end, and flows around after hitting the rear disc of the impeller. Therefore, the air flow at the inlet end of the casing is greater than the air flow at the other end of the casing. , is the strong wind end, and the other end of the shell is the weak wind end due to the small air flow. However, because the air duct width of the strong wind end and the air duct width of the weak wind end in the casing are the same, it is easy to cause the wind of the weak wind end with a small air flow. The duct cannot be filled with airflow, and the parts without airflow will generate negative pressure, resulting in turbulent airflow, which will affect the working efficiency of the centrifugal fan, which in turn affects the working efficiency of the dryer.

Therefore, there is a need in the art for a new centrifugal fan casing and corresponding centrifugal fan and clothes dryer to solve the above problems.

SUMMARY OF THE INVENTION

In order to solve the above problems in the prior art, that is, in order to solve the problem that airflow disturbances easily occur in the air duct of the existing centrifugal fan, thereby affecting the working efficiency of the centrifugal fan, the present invention provides a casing of the centrifugal fan. A layered structure is arranged in the air duct, and the layered structure is arranged to be capable of separating at least a part of the air duct into at least two wind layers, and the width of the wind layer near the strong wind end is greater than the width of the wind layer near the weak wind end.

In the preferred technical solution of the above-mentioned housing, the layered structure is arranged close to the outlet end of the air duct.

In a preferred technical solution of the above housing, the layered structure is a layered platform attached to or formed on the inner wall of the housing, and the layered platform divides the air duct into a first air layer and a second wind layer, wherein the first wind layer is close to the strong wind end, and the second wind layer is close to the weak wind end.

In the preferred technical solution of the above-mentioned housing, the cross-sectional width of the layered stage gradually increases along the direction of the gas flow toward the outlet end of the air duct.

In the preferred technical solution of the above housing, the windward end of the layered platform smoothly transitions from the inner wall of the housing.

In the preferred technical solution of the above-mentioned housing, the height of the layered table gradually decreases along the direction of the gas flowing toward the outlet end of the air duct.

In the preferred technical solution of the above-mentioned housing, the height of the layered table gradually decreases along the direction of the gas flowing toward the outlet end of the air duct.

In the preferred technical solution of the above-mentioned casing, the inner side surface of the layering table is inclined relative to the inner wall of the casing.

In a preferred technical solution of the above housing, the layered structure is a layered platform attached to or formed on the inner wall of the housing, and the layered platform includes at least two stepped parts to The road is divided into at least three wind layers.

In the preferred technical solution of the above-mentioned housing, the cross-sectional width of each step portion of the layered table gradually increases along the direction of gas flow toward the outlet end of the air duct.

In the preferred technical solution of the above housing, the windward end of the layered platform smoothly transitions from the inner wall of the housing.

In the preferred technical solution of the above-mentioned housing, the height of each step portion of the layered platform gradually decreases along the direction of the gas flowing toward the outlet end of the air duct.

In the preferred technical solution of the above-mentioned housing, the height of each step portion of the layered platform gradually decreases along the direction of the gas flowing toward the outlet end of the air duct.

In a preferred technical solution of the above housing, the layered structure is a layered stage attached to or formed on the inner wall of the housing, and the inner side of the layered stage is inclined from the inner wall of the housing extends to the bottom wall of the housing.

In the preferred technical solution of the above-mentioned housing, the cross-sectional width of the layered stage gradually increases along the direction of the gas flow toward the outlet end of the air duct.

In the preferred technical solution of the above housing, the windward end of the layered platform smoothly transitions from the inner wall of the housing.

In a preferred technical solution of the above-mentioned housing, the height of the position where the layered platform intersects the inner wall of the housing gradually decreases along the direction of gas flow toward the outlet end of the air duct.

In a preferred technical solution of the above-mentioned housing, the height of the position where the layered platform intersects the inner wall of the housing gradually decreases along the direction of gas flow toward the outlet end of the air duct.

In the preferred technical solution of the above-mentioned housing, the layered structure is fixedly connected to or integrated with the inner wall of the housing.

In the preferred technical solution of the above-mentioned housing, the height of the layered table is 1/2 to 3/4 of the height of the inner wall of the housing.

In another aspect, the present invention also provides a centrifugal fan comprising the above-mentioned housing.

In another aspect, the present invention also provides a clothes dryer comprising the above centrifugal fan.

Those skilled in the art can understand that, in the preferred technical solution of the present invention, by arranging a layered structure in the air duct, the air duct is divided into at least two wind layers by the layered structure, and the width of the wind layer close to the strong wind end is It is larger than the width of the wind layer near the weak wind end, that is, the width of the air duct at the weak wind end is adjusted through a layered structure, so that the width of the air duct at the weak wind end matches the airflow at the weak wind end, so as to avoid the situation that the air duct cannot be filled with airflow. Occurs, so as to avoid the occurrence of turbulent airflow in the air duct, thereby avoiding affecting the working efficiency of the centrifugal fan.

Further, the windward end of the layered platform smoothly transitions with the inner wall of the shell. By smoothly transitioning the windward end and the inner wall of the casing, the air flow on the inner wall of the casing can be smoothly transitioned to the inner side of the layered table.

In addition, the centrifugal fan further provided by the present invention on the basis of the above-mentioned technical solution adopts the above-mentioned casing, and further has the technical effect possessed by the above-mentioned casing. Compared with the centrifugal fan before the improvement, the centrifugal fan of the present invention has There is almost no airflow disorder in the air duct, and its work efficiency is greatly improved.

Description of drawings

Preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

Fig. 1 is the structural representation of the centrifugal fan of the present invention;

2 is a schematic structural diagram of Embodiment 1 of the centrifugal fan of the present invention;

3 is a schematic structural diagram of Embodiment 2 of the centrifugal fan of the present invention;

FIG. 4 is a schematic structural diagram of Embodiment 3 of the centrifugal fan of the present invention.

Detailed ways

First of all, those skilled in the art should understand that the embodiments described below are only used to explain the technical principle of the present invention, and are not intended to limit the protection scope of the present invention.

It should be noted that, in the description of the present invention, the terms "front", "rear", "upper", "middle", "lower", "top", "bottom", "inner", "outer" and the like indicate The terminology of the direction or positional relationship is based on the direction or positional relationship shown in the drawings, which is only for convenience of description and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore It should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In addition, it should be noted that, in the description of the present invention, unless otherwise expressly specified and limited, the terms "installed", "arranged", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed The connection can also be a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Based on the background art, it is pointed out that the airflow disorder is likely to occur in the air duct of the existing centrifugal fan, thereby affecting the working efficiency of the centrifugal fan. The invention provides a casing of a centrifugal fan, a centrifugal fan and a clothes dryer, aiming at effectively avoiding the disturbance of airflow in the air duct of the centrifugal fan, thereby avoiding affecting the working efficiency of the centrifugal fan.

Specifically, as shown in FIG. 1 , the centrifugal fan of the present invention includes a casing 1, an impeller is arranged in the casing 1, a layered structure is arranged in the air duct of the casing 1, and the layered structure is arranged to be able to divide at least the air duct. A part is divided into at least two wind layers, and the width of the wind layer near the strong wind end is greater than the width of the wind layer near the weak wind end. It can be known from the background technology that since the gas enters from the bottom of the casing 1 and flows upward, and flows to the surrounding after hitting the impeller, the air flow at the top of the casing 1 is greater than that at the bottom of the casing 1. The top of 1 is the strong wind end because of the large air flow, and the bottom of the shell 1 is the weak wind end because of the small air flow. The width of the air ducts (that is, the bottom of the housing 1) is the same, which easily leads to the fact that the air ducts at the weak wind end with small airflow cannot be filled with airflow, and the parts without airflow will generate negative pressure, causing airflow disorder, thus affecting the centrifugal fan. work efficiency. To this end, the present invention sets a layered structure in the air duct, the air duct is divided into at least two wind layers by the layered structure, and the width of the wind layer near the strong wind end is larger than the width of the wind layer near the weak wind end, that is, by layering The structure is used to adjust the width of the air duct at the weak wind end, so that the width of the air duct at the weak wind end matches the airflow at the weak wind end, so as to avoid the situation that the air duct cannot be filled with airflow. Wherein, the layered structure and the inner wall of the housing 1 can be fixedly connected or integrated, and those skilled in the art can flexibly set the specific connection form between the layered structure and the inner wall of the housing 1 in practical applications, as long as the layered structure can be integrated. The structure can be fixedly connected with the inner wall of the housing 1 . In addition, the layered structure can be arranged in the entire air duct, or the layered structure can be arranged on a certain section of the air duct, in a preferred case, the layered structure can be arranged close to the outlet end 4 of the air duct, etc. , the adjustment and change of the specific arrangement position of the layered structure does not deviate from the principle and scope of the present invention, and should be limited within the protection scope of the present invention. It should be pointed out that, in this application, "the layered structure is arranged close to the outlet end of the air duct" includes both the case where the layered structure is arranged at the outlet end of the air duct, and the case where the layered structure is slightly extended to the inside of the air duct. The specific extension range will be different in different application scenarios. In principle, the inward extension range of the layered structure in the airflow direction should not exceed the centerline of the impeller.

The technical solution of the present invention will be described in detail below by taking the layered structure arranged at the outlet end 4 of the air duct as an example.

Example 1

The technical solution of Embodiment 1 of the present invention will be described below with reference to FIG. 2 , wherein FIG. 2 is a schematic structural diagram of Embodiment 1 of the centrifugal fan of the present invention.

As shown in FIG. 2 , the centrifugal fan of the present invention includes a casing 1 , an impeller 2 is arranged in the casing 1 , a layered structure is arranged in the air duct of the casing 1 , and the layered structure is attached to or formed in the casing 1 . The stratified table 3A on the inner wall 11 of the Close to the strong wind side, and the second wind layer is close to the weak wind side. That is, the air duct in the casing 1 is divided into two wind layers by the layering table 3A, the first wind layer and the second wind layer. The layer is close to the weak wind end, ie at the bottom of the shell 1 . As can be seen from the foregoing, since the gas enters from the bottom of the casing 1 and flows upward, and flows around after hitting the rear disc 21 of the impeller, the airflow at the top of the casing 1 is greater than the airflow at the bottom of the casing 1, Therefore, the width of the first wind layer is greater than the width of the second wind layer. Wherein, the layering table 3A can be integrally formed with the inner wall 11 of the casing 1, that is, the layering table 3A is a structure formed on the inner wall 11 of the casing 1, or the layering table 3A can also be set as a separate component, Attached to the inner wall 11 of the casing 1 by sticking, magnetic adsorption or riveting, etc., those skilled in the art can flexibly set the specific connection form of the layering table 3A and the inner wall 11 of the casing 1 in practical applications , as long as the layer table 3A can be fixedly connected to the inner wall 11 of the casing 1 . In addition, it has been verified through repeated experiments by the inventor that when the height of the layer table 3A (H shown in FIG. 2 ) is 1/2 to 3/4 of the height of the inner wall 11 of the casing 1, the wind can be better avoided. Disturbance of airflow in the tract. Of course, the protection scope of the present invention is not limited to this. In practical applications, when the height of the layered table 3A is set to other values, it will also fall within the protection scope of the present invention. In addition, it should be noted that, in practical applications, those skilled in the art can divide the air duct in the second air layer into multiple air layers according to the distribution of the air flow in the air duct. In a preferred situation, the inner side surface 3A2 of the layered table 3A can be inclined relative to the inner wall 11 of the casing 1 (ie, inclined relative to the vertical direction), and the layered table 3A can displace the wind of the second wind layer. The track is smoothly divided into numerous smoothly transitioning wind layers.

Preferably, the cross-sectional width of the layered table 3A gradually increases along the direction of gas flow toward the outlet end 4 of the air duct. Since the width of the air duct gradually increases along the direction of the gas flow to the outlet end 4 of the air duct, in order to ensure that the width of the second air layer matches the airflow of the second air layer, the cross-sectional width of the layered table 3A is (L described in FIG. 2 ) also gradually increases in the direction of the gas flow to the outlet end 4 of the air duct.

Preferably, the windward end 3A1 of the layered platform 3A smoothly transitions with the inner wall 11 of the casing 1 . By smoothly transitioning the windward end 3A1 and the inner wall 11 of the casing 1 , the airflow on the inner wall 11 of the casing 1 can be smoothly transitioned to the inner side surface 3A2 of the layer table 3A.

Preferably, the height of the layered table 3A gradually decreases along the direction of the gas flow toward the outlet end 4 of the air duct. The height of the layered platform 3A refers to H in FIG. 2 , and the value of H gradually decreases from the windward end 3A1 of the layered platform 3A along the direction of the gas flow to the outlet end 4 of the air duct.

Embodiment 2

The technical solution of the second embodiment of the present invention will be described below with reference to FIG. 3 , wherein FIG. 3 is a schematic structural diagram of the second embodiment of the centrifugal fan of the present invention.

As shown in FIG. 3 , the centrifugal fan of the present invention includes a casing 1 , an impeller 2 is arranged in the casing 1 , a layered structure is arranged in the air duct of the casing 1 , and the layered structure is attached to or formed in the casing 1 . The tiered table 3B on the inner wall 11 of the 11 , the tiered table 3B includes two steps to separate the air duct into three air layers. Wherein, the layered platform 3B includes a first step portion 3B1 and a second step portion 3B2, and the air duct is divided into three air layers by the first step portion 3B1 and the second step portion 3B2, the upper wind layer, the middle wind layer and the downwind layer, The upper wind layer is close to the strong wind end, that is, at the top of the shell 1, the leeward layer is close to the weak wind end, that is, at the bottom of the shell 1, and the middle wind layer is located between the upper wind layer and the leeward layer. The bottom of the casing 1 enters and flows upward, and flows around after hitting the rear disc 21 of the impeller. Therefore, the airflow at the top of the casing 1 is greater than the airflow at the bottom of the casing 1, so the width of the upper wind layer is greater than that of the leeward layer. , the width of the stroke layer is greater than the width of the leeward layer and less than the width of the windward layer. Of course, the layered table 3B is not limited to two steps, that is, the air duct is not limited to three air layers. In practical applications, those skilled in the art can flexibly set the specific air layers in the air duct according to the specific distribution of the air flow in the air duct. The number is as long as it can avoid the occurrence of turbulent airflow in the air duct. Wherein, the layering table 3B can be integrally formed with the inner wall 11 of the casing 1, that is, the layering table 3B is a structure formed on the inner wall 11 of the casing 1, or the layering table 3B can also be set as a separate component, Attached to the inner wall 11 of the casing 1 by sticking, magnetic adsorption or riveting, etc., those skilled in the art can flexibly set the specific connection form of the layering table 3B and the inner wall 11 of the casing 1 in practical applications , as long as the layer table 3B can be fixedly connected to the inner wall 11 of the casing 1 .

Preferably, as shown in FIG. 3 , the cross-sectional width of each step portion of the layered stage 3B gradually increases along the direction of gas flow toward the outlet end 4 of the air duct. Since the width of the air duct gradually increases along the direction of the gas flow to the outlet end 4 of the air duct, in order to ensure that the width of the aerodynamic layer matches the airflow of the air duct, the cross-sectional width of the first step portion 3B1 (Fig. 3 L1) shown in also gradually increases along the direction of the gas flow to the outlet end 4 of the air duct. Similarly, in order to ensure that the width of the leeward layer matches the airflow of the leeward layer, the width of the cross-section of the second step portion 3B2 (L2 shown in FIG. 3 ) also gradually becomes larger in the direction of gas flow toward the outlet end 4 of the air duct.

Preferably, the windward end of the layered platform 3B smoothly transitions with the inner wall 11 of the housing 1 . That is, the windward end 3B11 of the first stepped portion 3B1 smoothly transitions to the inner wall 11 of the casing 1 . The airflow on the upper surface smoothly transitions to the inner side surface 3B12 of the first step portion 3B1. Similarly, the windward end 3B21 of the second stepped portion 3B2 and the inner wall 11 of the casing 1 smoothly transition. The airflow on the inner wall 11 smoothly transitions to the inner side surface 3B22 of the second stepped portion 3B2.

Preferably, the height of each step portion of the layered table 3B gradually becomes lower along the direction of the gas flow toward the outlet end 4 of the air duct. The height of the first step portion 3B1 refers to H1 in FIG. 3 , and the value of H1 gradually decreases from the windward end 3B11 of the first step portion 3B1 along the direction of the gas flow to the outlet end 4 of the air duct. The height of the portion 3B2 refers to H2 in FIG. 3 , and the value of H2 gradually decreases from the windward end 3B21 of the second step portion 3B2 along the direction of the gas flow to the outlet end 4 of the air duct.

Embodiment 3

The technical solution of the third embodiment of the present invention will be described below with reference to FIG. 4 , wherein FIG. 4 is a schematic structural diagram of the third embodiment of the centrifugal fan of the present invention.

As shown in FIG. 4 , the centrifugal fan of the present invention includes a casing 1 , an impeller 2 is arranged in the casing 1 , a layered structure is arranged in the air duct of the casing 1 , and the layered structure is attached to or formed in the casing 1 . The layered table 3C on the inner wall 11 of the layered table 3C, the inner side surface 3C2 of the layered table 3C extends obliquely from the inner wall 11 of the casing 1 to the bottom wall 12 of the casing 1 . That is, the layering table 3C smoothly divides the air duct into countless smooth transition air layers. As can be seen from the above, since the gas enters from the bottom of the casing 1 and flows upward, it flows around after hitting the rear disc 21 of the impeller. Therefore, the airflow at the top of the housing 1 is greater than the airflow at the bottom of the housing 1, so the width of the wind layer near the strong wind end (located at the top of the housing 1) is greater than that near the weak wind end (located at the bottom of the housing 1) ) the width of the wind layer. Wherein, the layering table 3C can be integrally formed with the inner wall 11 of the casing 1, that is, the layering table 3C is a structure formed on the inner wall 11 of the casing 1, or the layering table 3C can also be set as a separate component, Attached to the inner wall 11 of the casing 1 by sticking, magnetic adsorption or riveting, etc., those skilled in the art can flexibly set the specific connection form of the layering table 3C and the inner wall 11 of the casing 1 in practical applications , as long as the layer table 3C can be fixedly connected to the inner wall 11 of the casing 1 .

Preferably, as shown in FIG. 4 , the cross-sectional width of the layered stage 3C gradually increases along the direction of the gas flow toward the outlet end 4 of the air duct. Since the width of the air duct gradually increases along the direction of the gas flow to the outlet end 4 of the air duct, in order to ensure that the width of each air layer can match the air flow of the air layer, the cross section of the layered table 3C The width (L shown in FIG. 4 ) also gradually increases in the direction of gas flow towards the outlet end 4 of the air duct.

Preferably, as shown in FIG. 4 , the windward end 3C1 of the layered table 3C and the inner wall 11 of the casing 1 smoothly transition. By smoothly transitioning the windward end 3C1 and the inner wall 11 of the casing 1 , the airflow on the inner wall 11 of the casing 1 can be smoothly transitioned to the inner side surface 3C2 of the layering table 3C.

Preferably, as shown in FIG. 4 , the height of the position where the layered table 3C intersects the inner wall 11 of the housing 1 (or the line where the inner side 3C2 intersects the inner wall 11 ) is along the gas flow to the outlet end 4 of the air duct direction gradually decreases. More specifically, the height of the position where the layered table 3C intersects the inner wall 11 refers to H in FIG. 4 , and the value of H is gradually increased from the windward end 3C1 of the layered table 3C along the direction of the gas flow to the outlet end 4 of the air duct. become smaller.

Finally, the present invention also provides a clothes dryer, which includes the centrifugal fan of the first embodiment, the second embodiment or the third embodiment.

So far, the technical solutions of the present invention have been described with reference to the preferred embodiments shown in the accompanying drawings, however, those skilled in the art can easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims (22)

1. A casing of a centrifugal fan, characterized in that a layered structure is provided in an air duct of the casing, and the layered structure is arranged to be capable of dividing at least a part of the air duct into at least two wind layers And the width of the wind layer close to the strong wind end is greater than the width of the wind layer close to the weak wind end. 2 . The housing according to claim 1 , wherein the layered structure is disposed near the outlet end of the air duct. 3 . 3. The housing of claim 1, wherein the layered structure is a layered table attached to or formed on an inner wall of the housing, the layered table connecting the air duct It is divided into a first wind layer and a second wind layer, wherein the first wind layer is close to the strong wind end, and the second wind layer is close to the weak wind end. 4 . The housing according to claim 3 , wherein the cross-sectional width of the layered stage gradually increases along the direction of gas flow toward the outlet end of the air duct. 5 . 5 . The casing according to claim 3 or 4 , wherein the windward end of the layered platform smoothly transitions with the inner wall of the casing. 6 . 6 . The housing according to claim 3 or 4 , wherein the height of the layered platform gradually decreases along the direction of gas flow toward the outlet end of the air duct. 7 . 7 . The housing according to claim 5 , wherein the height of the layered platform gradually decreases along the direction of gas flow toward the outlet end of the air duct. 8 . 8 . The casing according to claim 3 , wherein the inner side surface of the layering table is inclined relative to the inner wall of the casing. 9 . 9. The housing of claim 1, wherein the layered structure is a layered platform attached to or formed on an inner wall of the housing, the layered platform comprising at least two steps Thereby, the air duct is divided into at least three air layers. 10 . The housing according to claim 9 , wherein the cross-sectional width of each step portion of the layered stage gradually increases along the direction of gas flow toward the outlet end of the air duct. 11 . 11. The casing according to claim 9 or 10, wherein the windward end of the layered platform smoothly transitions with the inner wall of the casing. 12 . The housing according to claim 9 or 10 , wherein the height of each step portion of the layered platform gradually decreases along the direction of gas flow toward the outlet end of the air duct. 13 . 13 . The housing according to claim 11 , wherein the height of each step portion of the layered platform gradually decreases along the direction of gas flow toward the outlet end of the air duct. 14 . 14. The housing of claim 1, wherein the layered structure is a layered table attached to or formed on an inner wall of the housing, the inner side of the layered table extending from the The inner wall of the casing extends obliquely to the bottom wall of the casing. 15 . The housing of claim 14 , wherein the cross-sectional width of the layered stage gradually increases along the direction of gas flow toward the outlet end of the air duct. 16 . 16. The casing according to claim 14 or 15, wherein the windward end of the layered platform smoothly transitions with the inner wall of the casing. 17. The casing according to claim 14 or 15, wherein the height of the position where the layered platform intersects the inner wall of the casing gradually decreases along the direction of gas flow toward the outlet end of the air duct . 18 . The casing of claim 16 , wherein the height of the position where the layered platform intersects the inner wall of the casing gradually decreases along the direction of gas flow toward the outlet end of the air duct. 19 . 19. The casing according to any one of claims 1 to 4, 8 to 10, and 14 to 15, wherein the layered structure is fixedly connected to or integrated with the inner wall of the casing. 20 . The casing according to claim 3 , wherein the height of the layered stage is 1/2 to 3/4 of the height of the inner wall of the casing. 21 . 21 . A centrifugal fan, characterized in that, the centrifugal fan comprises the housing according to any one of claims 1 to 20 . 22. A clothes dryer, wherein the clothes dryer comprises the centrifugal fan of claim 21.

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