Centrifugal fan and washing apparatus having the same

Abstract

The present invention relates to a centrifugal fan and a washing apparatus having the same. The centrifugal fan comprises: a volute having a volute axial air inlet side wall on which a volute air inlet is provided; and an impeller configured to be rotatably disposed in the volute and having an impeller axial air inlet side wall with a first axial gap between the impeller axial air inlet side wall and the volute axial air inlet side wall, on which an impeller air inlet alignable with the volute air inlet is provided, wherein an outer annular protrusion extending outwardly from the impeller axial air inlet side wall is provided around the impeller air inlet, and an inner annular protrusion extending inwardly from the volute axial air inlet side wall is provided around the volute air inlet, the outer annular protrusion and the inner annular protrusion are opposite to each other and spaced apart by a second axial gap, the second axial gap is smaller than the first axial gap, so that the outer annular protrusion and the inner annular protrusion together constitute an air internal circulation blocking structure. Such a blocking structure can substantially eliminate the air internal circulation phenomenon and increase the air supply amount.

Description

Technical Field

[0001] This invention relates to washing equipment, and more particularly to centrifugal fans and washing equipment having the same. Background Technology

[0002] Some existing washing machines, such as drum heat pump washer-dryers, have a drying system that dries washed, damp items (such as clothes). The drying system typically includes a fan, a heater, and an evaporator or other device to cool the humid air. During the drying process, the fan blows hot air, heated by the heater, into the washing drum. This hot air mixes with the damp clothes inside the drum, creating a humid airflow. The humid airflow is then exhausted from the washing drum into a return air duct. In the return air duct, the humid airflow is cooled by the evaporator, causing the water vapor to condense into water droplets, thus dehumidifying and cooling the airflow. The dehumidified airflow is then re-drawn in by the fan for a new cycle.

[0003] The air volume delivered by the fan is a key factor affecting the drying efficiency of washing equipment. Currently, centrifugal fans are commonly used. These centrifugal fans consist of a volute and an impeller rotatably housed within the volute. Air inlets are located on the axial inlet sidewall of the volute and on the axial inlet sidewall of the impeller. In the assembled state of the volute and impeller, the two air inlets are aligned, and the axial inlet sidewalls of the volute and impeller face each other, but a gap is left between them to allow the impeller to rotate relative to the volute. Since the gap between the impeller and the volute connects the impeller's inlet and outlet, a potential air circulation path is formed within the centrifugal fan. When the centrifugal fan operates, a portion of the airflow returns from the impeller's radial outlet along this air circulation path to the impeller's inlet and is re-drawn in by the impeller. Figure 1 As indicated by the white arrow, this creates an ineffective circulation of air within the centrifugal fan (which can be referred to as "air recirculation"). This air recirculation reduces the effective airflow of the centrifugal fan, thereby reducing the drying efficiency of the washing equipment.

[0004] Accordingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, specifically the technical issue of internal air circulation in centrifugal fans, this invention provides a centrifugal fan comprising: a volute having an axial air inlet sidewall and an air inlet on the axial air inlet sidewall; and an impeller rotatably disposed within the volute and having an impeller axial air inlet sidewall, with a first axial gap between the impeller axial air inlet sidewall and the volute axial air inlet sidewall, and an impeller air inlet on the impeller axial air inlet sidewall aligned with the volute air inlet. An outer annular protrusion extending outward from the impeller axial air inlet sidewall is provided around the impeller air inlet, and an inner annular protrusion extending inward from the volute axial air inlet sidewall is provided around the volute air inlet. The outer and inner annular protrusions are configured to face each other and spaced apart by a second axial gap, the second axial gap being smaller than the first axial gap, such that the outer and inner annular protrusions together constitute an internal air circulation blocking structure.

[0006] Those skilled in the art will understand that in the technical solution of the centrifugal fan of the present invention, an inner annular protrusion extending inward from the axial inlet sidewall of the volute is provided around the volute inlet, and an outer annular protrusion extending outward from the axial inlet sidewall of the impeller is provided around the impeller inlet. The inner and outer annular protrusions are opposite to each other and separated by a second axial gap, which is smaller than the first axial gap between the volute axial inlet sidewall and the impeller axial inlet sidewall. Clearly, due to the obstruction of the inner and outer annular protrusions and the narrowed flow channel, the resistance to airflow through the second axial gap is significantly greater than the resistance to airflow through the first axial gap. Therefore, the outer and inner annular protrusions together can prevent airflow from flowing into the impeller inlet from the first axial gap. In other words, the outer and inner annular protrusions together constitute an internal airflow obstruction structure, which can essentially eliminate the internal airflow phenomenon, thereby increasing the effective air volume of the centrifugal fan.

[0007] In the preferred embodiment of the centrifugal fan described above, the outer annular protrusion includes multiple outer annular steps, and the inner annular protrusion includes multiple inner annular steps corresponding to the multiple outer annular steps. These multiple steps extending axially along the fan form a flow channel with multiple approximately right-angle bends, thereby achieving multi-stage obstruction of the wind. Therefore, the more steps are added, the better the effect of the internal airflow obstruction structure becomes.

[0008] In the preferred embodiment of the centrifugal fan described above, inner annular grooves are formed between adjacent inner annular steps of the multi-stage inner annular steps. By configuring these inner annular grooves, the total weight of the volute can be reduced, and the amount of material used for the volute can also be saved.

[0009] In the preferred embodiment of the centrifugal fan described above, the multi-stage outer annular steps include three stages, and the multi-stage inner annular steps include three stages. The three stages of outer and inner annular steps together form three wind barriers that prevent internal air circulation, while the overall manufacturing process of the fan is relatively simple.

[0010] In the preferred embodiment of the centrifugal fan described above, a multi-stage outer annular step is provided around the air inlet of the volute, extending outward from the axial air inlet sidewall of the volute. Each stage of the outer annular step extends in the opposite direction axially to the corresponding stage of the inner annular step. These outer annular steps are designed to reduce the weight of the volute and also save on the amount of material used.

[0011] In the preferred embodiment of the centrifugal fan described above, the outer annular protrusion and the inner annular protrusion are configured to share a centerline with the volute inlet and the impeller inlet. Using the same centerline simplifies and facilitates the manufacturing of the centrifugal fan.

[0012] In the preferred embodiment of the centrifugal fan described above, the outer annular protrusion is positioned close to the impeller inlet, and the inner annular protrusion is positioned close to the volute inlet. Manufacturing the inner annular protrusion close to the volute inlet and the outer annular protrusion close to the impeller inlet requires essentially no change to the dimensions of the volute and impeller, yet it enables the centrifugal fan to prevent internal air recirculation.

[0013] In the preferred embodiment of the centrifugal fan described above, the impeller is disc-shaped, and multiple evenly spaced radial impeller outlets are formed on the outer circumference of the impeller. These radial impeller outlets connect to an annular exhaust chamber formed within the volute. The disc-shaped impeller is not only small in size but also easy to manufacture.

[0014] In the preferred embodiment of the centrifugal fan described above, the volute further includes a motor mounting wall opposite to the axial air inlet side wall of the volute. The motor mounting wall has a motor shaft hole and a plurality of motor mounting holes arranged circumferentially around the motor shaft hole. These motor mounting holes facilitate fixing the motor to the volute.

[0015] The present invention also provides a washing apparatus, wherein the washing apparatus is provided with a drying system, and the drying system includes a centrifugal fan as described above. By using the centrifugal fan of the present invention, the drying air volume of the washing apparatus can be increased, thereby improving the drying efficiency of the washing apparatus. Attached Figure Description

[0016] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0017] Figure 1This is a schematic diagram showing the internal air circulation path of the centrifugal fan in existing washing equipment;

[0018] Figure 2 This is a partial cross-sectional perspective view of an embodiment of the centrifugal fan of the present invention;

[0019] Figure 3 This is a partial cross-sectional plan view of an embodiment of the centrifugal fan of the present invention;

[0020] Figure 4 This is a three-dimensional schematic diagram of a portion of an embodiment of the centrifugal fan casing of the present invention;

[0021] Figure 5 This is a partial plan view of an embodiment of the volute of the centrifugal fan of the present invention;

[0022] Figure 6 It is along Figure 5 A partial cross-sectional schematic diagram of an embodiment of the volute of the centrifugal fan of the present invention, with EE cross-section lines;

[0023] Figure 7 yes Figure 6 A partially enlarged view of part F of an embodiment of the centrifugal fan casing of the present invention shown;

[0024] Figure 8 This is a perspective schematic diagram of an embodiment of the impeller of the centrifugal fan of the present invention;

[0025] Figure 9 This is a front view of an embodiment of the impeller of the centrifugal fan of the present invention;

[0026] Figure 10 This is a right view of an embodiment of the impeller of the centrifugal fan of the present invention;

[0027] Figure 11 yes Figure 10 The diagram shows a partial enlarged view of part G of an embodiment of the impeller of the centrifugal fan of the present invention.

[0028] List of reference numerals:

[0029] 1. Centrifugal fan; 11. Volute; 111. Volute inlet; 112. Axial inlet sidewall of volute; 113. Annular exhaust chamber; 114. Motor mounting wall; 141. Motor shaft hole; 142. Circumferential end wall; 143. First circumferential rib wall; 144. Second circumferential rib wall; 145. First radial rib; 146. Second radial rib; 147. Motor mounting hole; 148. Third radial rib; 115. Circumferential wall of volute inlet; 116. Outer annular step of volute; 116a. First-stage outer annular step of volute; 116b. Second-stage outer annular step of volute; 116c. Third-stage outer annular step of volute; 117. Reinforcing rib on axial inlet sidewall of volute; 118. Volute outlet; 12. Impeller; 121. Impeller inlet; 122. Impeller 123. Axial inlet sidewall; 124. Blade; 125. Blade bottom wall; 126. Impeller inlet peripheral wall; 127. Central shaft hub; 128. Central shaft hole; 129. Impeller outer perimeter; 13. Radial impeller outlet; 14. Internal air circulation blocking structure; 15. Inner annular protrusion; 16. First-stage inner annular step; 17. Second-stage inner annular step; 18. Third-stage inner annular step; 19. Outer annular protrusion; 10. First-stage outer annular step; 11. Second-stage outer annular step; 12. Third-stage outer annular step; 12. Inner annular groove; 12. First inner annular groove; 12. Second inner annular groove; 13. Third inner annular groove; 14. First axial clearance; 15. Second axial clearance. Detailed Implementation

[0030] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0031] It should be noted that in the description of this invention, terms such as "upper," "lower," "left," "right," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" 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 direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] To address the technical problem of internal air circulation in centrifugal fans, this invention provides a centrifugal fan 1. The centrifugal fan 1 includes: a volute 11 having an axial air inlet sidewall 112, on which an air inlet 111 is provided; and an impeller 12, rotatably disposed within the volute 11 and having an axial air inlet sidewall 122, with a first axial gap 14 between the impeller axial air inlet sidewall 122 and the volute axial air inlet sidewall 112, and an impeller air inlet 121 on the impeller axial air inlet sidewall 122 that can be aligned with the air inlet 111. An outer annular protrusion 132 extending outward from the impeller axial air inlet sidewall 122 is provided around the impeller air inlet 121, and an inner annular protrusion 131 extending inward from the volute axial air inlet sidewall 112 is provided around the volute air inlet 111. The outer annular protrusion 132 and the inner annular protrusion 131 are arranged opposite each other and spaced apart by a second axial gap 15, the second axial gap 15 being smaller than the first axial gap 14, such that the outer annular protrusion 132 and the inner annular protrusion 131 together constitute an internal air circulation blocking structure 13. Figure 3 As shown, the airflow b entering the first axial gap 14 between the axial inlet sidewall 112 of the volute and the axial inlet sidewall 122 of the impeller is blocked when it encounters the outer annular protrusion 132 and the inner annular protrusion 131 protruding from both sides into the first axial gap 14. Furthermore, the width D2 of the second axial gap 15 between the outer annular protrusion 132 and the inner annular protrusion 131 is significantly smaller than the width D1 of the first axial gap 14, significantly increasing the resistance for the airflow b to pass through the second axial gap 15. Ultimately, this forces the airflow b to change direction and flow into the annular exhaust chamber 113 of the volute 11. Further, the second axial gap 15 may have multiple bends to further increase the resistance to airflow.

[0034] Figure 2 This is a partial cross-sectional perspective view of an embodiment of the centrifugal fan of the present invention, and Figure 3 This is a partial cross-sectional plan view of an embodiment of the centrifugal fan of the present invention. For example... Figure 2 and Figure 3As shown, the centrifugal fan 1 of the present invention includes a volute 11 and an impeller 12. The impeller 12 is rotatably arranged within the volute 11. The centrifugal fan 1 also includes a motor (not shown in the figure). The impeller 12 is fixedly connected to the drive shaft of the motor. When the centrifugal fan 1 is operating, the impeller 12 is driven to rotate within the volute 11 by the drive shaft of the motor (not shown in the figure). Air is drawn into the impeller 12 in the direction of arrow a (also known as the axial direction), and then discharged radially into the annular exhaust chamber 113 of the volute 11, finally exiting from the volute outlet 118 (see...). Figure 4 The impeller 12 is blown out. A suitable clearance needs to be maintained between the impeller 12 and the volute 11 to allow unimpeded rotation of the impeller 12 within the volute 11. This clearance includes axial clearances on the two opposing axial sides of the impeller 12 (along the direction of the centerline c) and radial clearances on the outer periphery of the impeller 12, such as a first axial clearance 14 on the inlet side. The first axial clearance 14 has a first axial width D1. Optionally, both the impeller 12 and the volute 11 can be made of suitable injection molding materials. For example, the impeller 12 can be manufactured by a one-time injection molding process. The manufactured impeller 12 is placed into a cavity for manufacturing the volute 11, and then the volute 11 is manufactured not only by a one-time injection molding process but also simultaneously assembled with the impeller 12. Alternatively, the impeller 12 and the volute 11 can also be made of other suitable metallic materials and by other suitable processes.

[0035] Figure 4 This is a perspective view of a portion of an embodiment of the centrifugal fan casing of the present invention. Figure 5 This is a partial plan view of an embodiment of the volute casing of the centrifugal fan of the present invention. Figure 6 It is along Figure 5 A partial cross-sectional schematic diagram of an embodiment of the centrifugal fan casing of the present invention, with EE cross-section lines. Figure 7 yes Figure 6 The diagram shows a partial enlarged view of part F of an embodiment of the centrifugal fan casing of the present invention. (See diagram for reference.) Figures 2 to 6 As shown, the volute 11 includes an axial inlet sidewall 112 and an opposing motor mounting wall 114. The axial inlet sidewall 112 and the motor mounting wall 114 together form an impeller chamber (not shown) that accommodates the impeller 12. An annular exhaust chamber 113 is formed around the radial outer periphery of the impeller chamber. The annular exhaust chamber 113 communicates with the impeller chamber to receive the airflow discharged from the impeller 12. Figure 2 and Figure 3 As shown, in one or more embodiments, the annular exhaust cavity 113 has a generally rectangular cross-section, and all four corners of this cross-section are rounded. Along the axial direction (i.e., the direction of the centerline c), the width of the cross-section of the annular exhaust cavity 113 is greater than the width of the impeller chamber's cross-section. Figure 4 and Figure 5 As shown, a volute air outlet 118 is provided in the circumferential direction of the annular exhaust cavity 113, and the annular exhaust cavity 113 is directly connected to the volute air outlet 118 so that air can be blown outward from the volute air outlet 118.

[0036] like Figure 2 and Figure 3 As shown, in one or more embodiments, the motor mounting wall 114 of the volute 11 is a thin wall with a predetermined thickness. This predetermined thickness can be determined according to actual needs. A motor shaft hole 141 is provided at the center of the motor mounting wall 114 to allow the motor drive shaft to rotatably pass through it. Figure 2 and Figure 3 As shown, on the outer surface of the motor mounting wall 114 (based on...) Figure 2 and Figure 3 The right side surface (as shown in the diagram) has a connecting groove (not shown) for accommodating the end of the motor's drive shaft (i.e., the end from which the drive shaft extends outward). The connecting groove is surrounded by a circumferential end wall 142. The circumferential end wall 142 extends vertically outward from the outer surface of the motor mounting wall 114 with the motor shaft hole 141 as its center, extending a first predetermined height. This first predetermined height can be determined according to actual needs. In the assembled state, the end of the motor's drive shaft is inserted into the connecting groove, and the motor's drive shaft extends through the motor shaft hole 141 into the impeller chamber.

[0037] like Figure 2 and Figure 3 As shown, in one or more embodiments, a first circumferential rib wall 143 and a second circumferential rib wall 144 are further provided on the outer surface of the motor mounting wall 114. Both the first circumferential rib wall 143 and the second circumferential rib wall 144 surround the circumferential end wall 142 and are concentric with it. The first circumferential rib wall 143 is located between the circumferential end wall 142 and the second circumferential rib wall 144, preferably at the midpoint between them. The first circumferential rib wall 143 and the second circumferential rib wall 144 extend vertically outward from the outer surface of the motor mounting wall 114 by a second predetermined height and a third predetermined height, respectively. These second and third predetermined heights can be determined according to actual needs. In one or more embodiments, the first circumferential rib wall 143 is approximately flush with the circumferential end wall 142, while the second circumferential rib wall 144 extends outward beyond both the first circumferential rib wall 143 and the circumferential end wall 142. Figure 2 As shown, in one or more embodiments, a plurality of first radial ribs 145 are provided between the first circumferential rib wall 143 and the circumferential end wall 142. Each first radial rib 145 extends radially from the circumferential end wall 142 to the first circumferential rib wall 143. Adjacent first radial ribs 145 are spaced at the same distance. Alternatively, adjacent first radial ribs 145 may be spaced unevenly as needed. Figure 2As shown, in one or more embodiments, a plurality of second radial ribs 146 are provided between the first circumferential rib wall 143 and the second circumferential rib wall 144. Each second radial rib 146 extends radially from the first circumferential rib wall 143 to the second circumferential rib wall 144. Adjacent second radial ribs 146 are spaced at the same distance. Alternatively, adjacent second radial ribs 146 may be spaced unevenly as needed. The first circumferential rib wall 143, the second circumferential rib wall 144, the first radial rib 145, and the second radial rib 146 together enhance the strength of the motor mounting wall 114.

[0038] like Figure 2 As shown, in one or more embodiments, a plurality of spaced-apart connecting posts (not shown) are provided along the second circumferential rib wall 144. Each connecting post has a motor connection hole 147. When the motor is assembled with the volute housing, the motor can be fixed to the volute housing 11 through these motor connection holes 147. Alternatively, the connecting posts may be separated from the second circumferential rib wall 144 or the second circumferential rib wall 144 may be omitted. Figure 2 As shown, in one or more embodiments, a plurality of third radial ribs 148 are provided between the second circumferential rib wall 144 and the sidewall forming the annular exhaust cavity 113. Each third radial rib 148 extends from the second circumferential rib wall 144 to the sidewall forming the annular exhaust cavity 113. Adjacent third radial ribs 148 are spaced at the same distance. Alternatively, adjacent third radial ribs 148 may be spaced unevenly as needed. The third radial ribs 148 can further improve the strength of the volute 11.

[0039] like Figures 3 to 6 As shown, a volute air inlet 111 is provided at the center of the axial air inlet sidewall 112 of the volute. The volute air inlet 111 is surrounded by the volute air inlet peripheral wall 115 around the center line c. The volute axial air inlet sidewall 112 extends approximately radially from the volute air inlet peripheral wall 115 to the sidewall forming the annular exhaust cavity 113. Figure 6 and Figure 7 As shown, an air inlet sidewall 112 extending inward from the axial direction of the volute is provided around the air inlet 111 of the volute (based on...). Figure 6 The inner annular protrusion 131 (extending to the right as shown) is an example. In one or more embodiments, the inner annular protrusion 131 shares a centerline c with the volute inlet 111, which facilitates the manufacture of the volute 11. Alternatively, depending on actual needs, the center of the inner annular protrusion 131 may be offset from the center of the volute inlet 111. Figure 7As shown, in one or more embodiments, the inner annular protrusion 131 is a three-stage inner annular step near the volute inlet 111: a first-stage inner annular step 131a, a second-stage inner annular step 131b, and a third-stage inner annular step 131c. The first-stage inner annular step 131a is adjacent to and surrounds the volute inlet peripheral wall 115. In one or more embodiments, to save material and reduce the weight of the volute 11, a first inner annular groove 133a is formed between the first-stage inner annular step 131a and the volute inlet peripheral wall 115. On the inner side of the axial air inlet sidewall 112 of the volute, the volute inlet peripheral wall 115 extends inward along the direction of the centerline c beyond the first-stage inner annular step 131a. The second-stage inner annular step 131b is adjacent to and surrounds the first-stage inner annular step 131a. On the inner side of the axial air inlet sidewall 112 of the volute, a second-stage inner annular step 131b extends inward along the direction of the centerline c, exceeding the first-stage inner annular step 131a. In one or more embodiments, to save material and reduce the weight of the volute 11, a second inner annular groove 133b is formed between the second-stage inner annular step 131b and the first-stage inner annular step 131a. A third-stage inner annular step 131c is adjacent to and surrounds the second-stage inner annular step 131b. On the inner side of the axial air inlet sidewall 112 of the volute, a third-stage inner annular step 131c extends inward along the direction of the centerline c, exceeding the second-stage inner annular step 131b. In one or more embodiments, to save material and reduce the weight of the volute 11, a third inner annular groove 133c is formed between the third-stage inner annular step 131c and the second-stage inner annular step 131b. The first inner annular groove 133a, the second inner annular groove 133b, and the third inner annular groove 133c all belong to the inner annular groove 133c.

[0040] Alternatively, the inner annular protrusion 131 may have one, two, or more than three steps. Optionally, the inner annular groove may be omitted between adjacent steps. Alternatively, the inner annular protrusion 131 may have other suitable forms of protrusion, such as corrugations, to block airflow. Alternatively, the inner annular protrusion 131 may be positioned away from the volute inlet 111, for example, positioned near the center of the inner side of the volute axial inlet sidewall 112.

[0041] like Figures 3 to 7 As shown, in one or more embodiments, an outer annular step 116 is provided on the outer side of the axial air inlet sidewall 112 of the volute surrounding the air inlet 111 of the volute, so that the axial air inlet sidewall 112 of the volute maintains a relatively thin wall and a lighter weight. Figure 7As shown, in one or more embodiments, the outer annular step 116 of the volute includes a first-stage outer annular step 116a, a second-stage outer annular step 116b, and a third-stage outer annular step 116c. The first-stage outer annular step 116a is adjacent to and surrounds the volute inlet peripheral wall 115. On the outer side of the axial air inlet sidewall 112 of the volute, the volute inlet peripheral wall 115 extends outward along the direction of the centerline c beyond the first-stage outer annular step 116a. The first-stage outer annular step 116a and the first-stage inner annular step 131a are aligned with each other along the direction of the centerline c and extend in opposite directions. The second-stage outer annular step 116b is adjacent to and surrounds the first-stage outer annular step 116a. On the outer side of the axial air inlet sidewall 112 of the volute, the first-stage outer annular step 116a extends outward along the centerline c beyond the second-stage outer annular step 116b. The second-stage outer annular step 116b and the second-stage inner annular step 131b are aligned with each other along the centerline c and extend in opposite directions. The third-stage outer annular step 116c is adjacent to and surrounds the second-stage outer annular step 116b. On the outer side of the axial air inlet sidewall 112 of the volute, the second-stage outer annular step 116b extends outward along the centerline c beyond the third-stage outer annular step 116c. The third-stage outer annular step 116c and the third-stage inner annular step 131c are aligned with each other along the centerline c and extend in opposite directions.

[0042] Alternatively, the outer annular step 116 of the volute can be a single, two, or more than three-stage step. Alternatively, the stepped protrusion on the outer side of the axial air intake sidewall 112 of the volute can be omitted. For example... Figure 4 As shown, in one or more embodiments, a plurality of reinforcing ribs 117 are provided on the outer side of the axial air inlet sidewall 112 of the volute. Each reinforcing rib 117 extends radially outward from the outer periphery of the outer annular step 116 of the volute to the sidewall forming the annular exhaust cavity 113. Adjacent reinforcing ribs 117 have the same circumferential distance. Alternatively, the circumferential distance between adjacent reinforcing ribs 117 may also be different depending on actual needs.

[0043] Figure 8 This is a perspective schematic diagram of an embodiment of the impeller of the centrifugal fan of the present invention. Figure 9 This is a front view schematic diagram of an embodiment of the impeller of the centrifugal fan of the present invention. Figure 10 This is a right view of an embodiment of the impeller of the centrifugal fan of the present invention, and Figure 11 yes Figure 10 The diagram shows a partial enlarged view of part G of an embodiment of the impeller of the centrifugal fan of the present invention. (See attached image.) Figures 8 to 10As shown, in one or more embodiments, the impeller 12 is a generally disc-shaped impeller. The impeller 12 has an axial inlet sidewall 122, a blade bottom wall 124, and a plurality of evenly spaced blades 123.

[0044] See Figure 2 and Figure 3 Each blade 123 is integrally formed with the blade base wall 124 and extends perpendicularly from the blade base wall 124 along the centerline c toward the impeller axial inlet sidewall 122. Each blade 123 is also integrally formed with the impeller axial inlet sidewall 122 near the outer periphery of the impeller 12, but near the center of the impeller 12, each blade 123 is spaced at a predetermined interval from the impeller axial inlet sidewall 122 to allow airflow to uniformly enter the gaps between all adjacent blades. See also Figure 2 and Figure 3 A central hub 126 is provided at the center of the blade bottom wall 124. The central hub 126 is a generally cylindrical body surrounding a centerline c. The central hub 126 is integrally formed with the blade bottom wall 124 and extends vertically from the blade bottom wall 124 along the centerline c toward the impeller axial inlet sidewall 122 at a predetermined height. This predetermined height should be lower than the maximum height of each blade 123. A central shaft hole 127 centered on the centerline c is formed at the center of the central hub 126. The central shaft hole 127 extends through the entire central hub 126. In the assembled state of the impeller 12 and the volute 11, the central shaft hole 127 is aligned with the motor shaft hole 141 on the motor mounting wall 114 and shares the centerline c. Therefore, the motor drive shaft can extend from the motor shaft hole 141 into the central shaft hole 127 and thus be fixed to the central hub 126, so that the motor can drive the impeller 12 to rotate via the drive shaft. Figure 8 and Figure 10 As shown, a plurality of radial impeller outlets 129 are evenly distributed on the radial outer periphery 128 of the impeller 12. Each radial impeller outlet 129 communicates with the gap between the corresponding blades 123 so that the airflow drawn into the impeller 12 can be discharged from the radial impeller outlet 129. In the assembled state of the impeller 12 and the volute 11, each radial impeller outlet 129 communicates with the annular exhaust chamber 113 of the volute 11.

[0045] like Figure 8 and Figure 9As shown, an impeller inlet 121 is provided at the center of the axial inlet sidewall 122 of the impeller. The impeller inlet 121 is centered on the centerline c and surrounded by the impeller inlet peripheral wall 125. In the assembled state of the impeller 12 and the volute 11, the impeller inlet 121 and the volute inlet 111 are aligned and share the centerline c. The impeller inlet peripheral wall 125 is fitted onto the inner end of the volute inlet peripheral wall 115 opposite to the impeller 12, and a predetermined radial gap is formed between the inner end and the outer periphery to allow the impeller 12 to rotate relative to the volute 11. Figure 10 and Figure 11 As shown, an outer annular protrusion 132 is provided on the outer side of the impeller axial inlet sidewall 122 surrounding the impeller inlet 121. This outer annular protrusion 132 extends outward from the impeller axial inlet sidewall 122 along the centerline c. In one or more embodiments, the outer annular protrusion 132 shares the centerline c with the impeller inlet 121, which facilitates the manufacture of the impeller 12. Depending on actual needs, the center of the outer annular protrusion 132 can be offset from the center of the impeller inlet 121. In one or more embodiments, the outer annular protrusion 132 is positioned close to the impeller inlet 121, an arrangement that eliminates the need to adjust the overall impeller size. In the assembled state of the impeller 12 and the volute 11, the outer annular protrusion 132 and the inner annular protrusion 131 are opposite each other and spaced apart by a second axial gap 15 smaller than the first axial gap 14, thus together forming an internal air circulation blocking structure 13.

[0046] like Figure 10 and Figure 11 As shown, in one or more embodiments, the outer annular protrusion 132 includes three levels of outer annular steps: a first level outer annular step 132a, a second level outer annular step 132b, and a third level outer annular step 132c. The first level outer annular step 132a is adjacent to and surrounds the impeller inlet peripheral wall 125. Along centerline c, the impeller inlet peripheral wall 125 extends outward beyond the first level outer annular step 132a. The second level outer annular step 132b is adjacent to and surrounds the first level outer annular step 132a. Along centerline c, the first level outer annular step 132a extends outward beyond the second level outer annular step 132b. The third level outer annular step 132c is adjacent to and surrounds the second level outer annular step 132b. Along centerline c, the second level outer annular step 132b extends outward beyond the third level outer annular step 132c. See also... Figure 2 and Figure 3In the assembled state of the impeller 12 and the volute 11, the first-stage outer annular step 132a of the impeller 12 faces the first-stage inner annular step 131a of the volute 11, forming a second axial gap 15 between them; the second-stage outer annular step 132b faces the second-stage inner annular step 131b, forming a second axial gap 15 between them; the third-stage outer annular step 132c faces the third-stage inner annular step 131c, forming a second axial gap 15 between them. Figure 3 As shown, the width D2 of the second axial clearance 15 is significantly smaller than the width D1 of the first axial clearance 14. Further, as... Figure 3 As shown, because the inner and outer annular steps of the three levels are staggered, the second axial gap 15 forms three approximately right-angle bends. This design of the second axial gap 15 will significantly increase the resistance of airflow through the second axial gap 15, thus further enhancing the effect of blocking internal air circulation.

[0047] Alternatively, the outer annular protrusion 132 may have one, two, or more than three steps, and match the inner annular protrusion 131. Alternatively, the outer annular protrusion 132 may have other suitable forms of protrusion, such as corrugations, to block airflow. Alternatively, the outer annular protrusion 132 may be positioned away from the impeller inlet 121, for example, positioned near the center of the outer side of the impeller axial inlet sidewall 122.

[0048] The present invention also relates to a washing apparatus (not shown in the figures). This washing apparatus includes, but is not limited to, drum washing machines and pulsator washing machines. The washing apparatus is equipped with a drying system (not shown in the figures), and includes any of the centrifugal fans 1 described above. By using the centrifugal fan 1, the effective airflow of the centrifugal fan can be increased without increasing the power of the centrifugal fan, thereby improving the drying efficiency of the washing apparatus.

[0049] The technical solutions of the present invention have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can combine technical features from different embodiments, or make equivalent changes or substitutions to related technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A centrifugal fan, characterized in that, The centrifugal fan includes: A volute, having an axial air inlet sidewall, on which an air inlet is provided; and An impeller is configured to be rotatably disposed within the volute and has an axial inlet sidewall, a first axial gap being formed between the axial inlet sidewall and the volute sidewall. An impeller inlet is provided on the axial inlet sidewall, which is aligned with the volute inlet. The impeller inlet has an outer annular protrusion extending outward from the axial inlet sidewall of the impeller, and the volute inlet has an inner annular protrusion extending inward from the axial inlet sidewall of the volute. The outer annular protrusion and the inner annular protrusion are arranged opposite each other and spaced apart by a second axial gap. The second axial gap is smaller than the first axial gap, so that the outer annular protrusion and the inner annular protrusion together constitute an internal air circulation blocking structure. The outer annular protrusion includes multiple outer annular steps, and the inner annular protrusion includes multiple inner annular steps corresponding to the multiple outer annular steps; a multi-level outer annular step of the volute is provided around the air inlet of the volute, extending outward from the axial air inlet sidewall of the volute, and each level of the outer annular step of the volute and the corresponding level of the inner annular step extend in opposite directions along the axial direction.

2. The centrifugal fan according to claim 1, characterized in that, An inner annular groove is formed between adjacent inner annular steps of the multi-level inner annular steps.

3. The centrifugal fan according to claim 1, characterized in that, The multi-level outer ring step includes three levels of outer ring steps, and the multi-level inner ring step includes three levels of inner ring steps.

4. The centrifugal fan according to any one of claims 1-3, characterized in that, The outer annular protrusion and the inner annular protrusion are configured to share a centerline with the volute air inlet and the impeller air inlet.

5. The centrifugal fan according to any one of claims 1-3, characterized in that, The outer annular protrusion is positioned close to the impeller air inlet, and the inner annular protrusion is positioned close to the volute air inlet.

6. The centrifugal fan according to any one of claims 1-3, characterized in that, The impeller is disc-shaped, and multiple evenly spaced radial impeller outlets are formed on the outer periphery of the impeller. The radial impeller outlets are connected to an annular exhaust chamber formed in the volute.

7. The centrifugal fan according to any one of claims 1-3, characterized in that, The volute also includes a motor mounting wall opposite to the axial air inlet side wall of the volute, and the motor mounting wall is provided with a motor shaft hole and a plurality of motor mounting holes arranged circumferentially around the motor shaft hole.

8. A washing device, characterized in that, The washing equipment is equipped with a drying system, and the drying system includes a centrifugal fan according to any one of claims 1-7.

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