Centrifugal fan for household appliance and household appliance

Abstract

The utility model relates to the field of household appliances, in particular to a centrifugal fan for a household appliance, comprising: a volute (21) forming an accommodating space; the impeller (22) is rotatably accommodated in the accommodating space (213) of the volute (21) and is used for sucking air and accelerating the air, the impeller (22) comprises an impeller inlet (221) and an impeller outlet (222), and the air enters from the impeller inlet (221) and flows out from the impeller outlet (222); wherein at least one first backflow prevention part (24) suitable for at least partially preventing the air flowing out of the impeller outlet (222) from flowing back towards the impeller inlet (221) is formed in the position, away from the impeller inlet (221), of the area, adjacent to the volute (21), of the impeller (22) in the flowing direction (A) of the air in the impeller (22), and the first backflow prevention part (24) is suitable for at least partially preventing the air flowing out of the impeller outlet (222) from flowing back towards the impeller inlet (221). The utility model also relates to a corresponding household appliance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of household appliances, in particular to a centrifugal fan for a household appliance. Furthermore, the present application also relates to a household appliance, such as a washer-dryer, comprising such a centrifugal fan. BACKGROUND

[0002] With the improvement of people's living quality, consumers have increasingly high requirements on the drying effect, efficiency and degree of garment protection of a garment treatment device, such as a washer-dryer.

[0003] The centrifugal fan in a washer-dryer plays a key role in achieving a fast and uniform drying process. Generally, ambient air is sucked from an impeller inlet by the centrifugal fan and is accelerated and pressurized by rotation of the impeller and flows out of an impeller outlet by centrifugal force.

[0004] However, there is a flow gap between the impeller and the volute. Since the pressure of the air from the impeller outlet is greater than that of the air at the impeller inlet, the air flowing out of the impeller outlet will partially backflow in the direction of the impeller inlet due to the pressure difference via the flow gap, which not only reduces the amount of air entering the volute and eventually entering the garment treatment drum, but also causes flow interference to the air flow at the impeller inlet, thereby also reducing the drying effect of the washer-dryer and increasing energy consumption.

[0005] In addition, the impeller inlet of the centrifugal fan is usually arranged in a space above the garment treatment drum in the washer-dryer, which is very limited and very important for the arrangement of compact structures or other components.

[0006] Therefore, there is still a need for further improvement of the centrifugal fan and the household appliance in the prior art for at least some of the above problems. SUMMARY

[0007] The purpose of the embodiments of the present application is to provide a centrifugal fan for a household appliance and a corresponding household appliance. By at least one embodiment of the present application, not only can the deficiencies of the centrifugal fan in the prior art be overcome, but also the efficiency of the centrifugal fan can be improved, energy consumption can be reduced, and user satisfaction can be improved.

[0008] According to a first aspect of the present application, a centrifugal fan for a household appliance is provided, the centrifugal fan comprising:

[0009] a volute forming a containing space;

[0010] an impeller rotatably accommodated in an accommodation space of the volute for sucking and accelerating air, wherein the impeller comprises an impeller inlet via which air enters and an impeller outlet from which air flows out;

[0011] wherein, at a region adjacent to the volute of the impeller, at least one first backflow prevention portion adapted to at least partially prevent backflow of air flowing out of the impeller outlet towards the impeller inlet is configured in a direction in which air flows in the impeller at a location away from the impeller inlet.

[0012] By this embodiment of the present application, not only can backflow of air from the impeller outlet to the impeller inlet in the centrifugal fan be reliably prevented or even avoided, improving the efficiency of the centrifugal fan, but also by arranging the backflow prevention portion not in the region of the impeller inlet, in particular not in the region below the edge of the impeller inlet, the space above the laundry treatment tub (below the edge of the impeller inlet) can be further occupied, thus also achieving a very compact arrangement and providing the possibility for arrangement of other components in this space.

[0013] Extension and improvement schemes of the technical solution of the present application are known from the following optional embodiments.

[0014] According to one optional embodiment of the centrifugal fan of the present application, in a state in which the impeller is arranged in the accommodation space, a gap is formed between the impeller and the inner wall of the volute, and the first backflow prevention portion at least partially prevents air from flowing towards the impeller inlet via the gap. By this embodiment, backflow of air flowing out of the impeller outlet to the impeller inlet via the gap can be reliably prevented.

[0015] According to one optional embodiment of the centrifugal fan of the present application, the first backflow prevention portion is arranged close to a first edge of the impeller outlet. Thereby, the arrangement of the first backflow prevention portion can be simplified and the backflow prevention effect can be reliably ensured.

[0016] According to one optional embodiment of the centrifugal fan of the present application, the first backflow prevention portion is provided on the volute and extends radially outward of the first edge of the impeller outlet. By this embodiment, the first backflow prevention portion configured on the inner side of the volute can reliably block air flowing out of the impeller outlet from flowing towards the impeller inlet via the space. Furthermore, since the first backflow prevention portion is arranged on the fixed, non-movable volute, the configuration of the first backflow prevention portion is simplified and the inertia caused by the moving mass of the first backflow prevention portion is avoided.

[0017] According to one optional embodiment of the centrifugal fan of the present application, the first backflow prevention portion is distributed continuously in the circumferential direction. Thereby, the backflow prevention effect can be improved and the efficiency of the centrifugal fan can be improved.

[0018] According to an optional embodiment of the centrifugal fan according to the present application, the volute includes a first casing and a second casing, the first casing and the second casing are connected to each other and form the accommodation space for accommodating the impeller, the gap is formed between the impeller and the second casing, wherein the first backflow prevention portion is arranged on the second casing and is configured to be at least flush with a first edge of the impeller outlet close to the second casing in the air flow direction in a state where the impeller is accommodated in the accommodation space. Thus, it is possible to reliably ensure that the air flows out from the impeller outlet to the outside via the upper edge of the first backflow prevention portion without interruption or obstruction along the flow direction. Thereby, the flow effect of the air flowing out from the impeller outlet is further improved and the efficiency of the centrifugal fan is further improved.

[0019] According to an optional embodiment of the centrifugal fan according to the present application, the first backflow prevention portion is arranged outside the first edge of the impeller outlet in the radial direction of the impeller. Thereby, the configuration of the first backflow prevention portion is simplified and interference of the first backflow prevention portion with the first edge of the impeller outlet due to installation tolerances is avoided.

[0020] According to an optional embodiment of the centrifugal fan according to the present application, the first backflow prevention portion is configured as a circumferentially continuously extending protrusion, the protrusion at least partially interrupts the flow of the air in the direction towards the impeller inlet via the gap. This simple structure of the first backflow prevention portion is easy to process.

[0021] According to an optional embodiment of the centrifugal fan according to the present application, at least one second backflow prevention portion adapted to at least partially prevent the air flowing out from the impeller outlet from flowing in the direction towards the impeller inlet via the gap is further configured close to the impeller inlet along the direction in which the air flows in the impeller. Thereby, the flow of the air in the direction towards the impeller inlet can be further prevented and the efficiency of the centrifugal fan is further improved.

[0022] According to an optional embodiment of the centrifugal fan according to the present application, the second backflow prevention portion is arranged on the second casing and is configured to be flush with the lower side of a second edge of the impeller inlet in the vertical direction in a state where the impeller is accommodated in the accommodation space. Thereby, while the backflow prevention effect is efficiently ensured, it is also possible to avoid occupying the space below the edge of the impeller inlet, so that a compact structure is realized and the possibility of arrangement of other components in the space is provided.

[0023] Alternatively, the second backflow prevention portion protrudes from the radially inner side of the second edge of the impeller inlet. Thereby, the configuration of the second backflow prevention portion can be simplified, the manufacturing cost is reduced and the backflow prevention effect is further improved.

[0024] According to a second aspect of the present application, a domestic appliance is provided, the domestic appliance comprising a centrifugal fan according to one of the above embodiments.

[0025] According to an optional embodiment of the domestic appliance of the present application, the domestic appliance is a washer-dryer, the washer-dryer comprising a laundry treatment tub, the centrifugal fan being located above the laundry treatment tub, the first backflow prevention portion being arranged only in the vicinity of the impeller outlet. Thereby, no space above the laundry treatment tub is occupied.

[0026] Further features of the present application will become apparent from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned in the above description and in the claims and those not expressly mentioned but inherent in the description and the claims, are not to be excluded from the scope of the present application. The features mentioned in the above description and in the claims are not to be understood as being restricted to the combinations explicitly mentioned, but that individual features can be freely combined with each other and with features not mentioned in the above description and in the claims. The features mentioned in the above description and in the claims may, both individually and in combination, be further developed in accordance with the application. The above description and the claims are to be understood as not being restricted to the details of the above description, but that they can be modified in any way within the scope of the application. The features mentioned in the above description and in the claims may, both individually and in combination, be further developed in accordance with the application. The above description and the claims are to be understood as not being restricted to the details of the above description, but that they can be modified in any way within the scope of the application. The features mentioned in the above description and in the claims may, both individually and in combination, be further developed in accordance with the application. The above description and the claims are to be understood as not being restricted to the details of the above description, but that they can be modified in any way within the scope of the application. BRIEF DESCRIPTION OF DRAWINGS

[0027] The principles, features and advantages of the present application will become better understood with reference to the following detailed description and accompanying drawings in which:

[0028] Figure 1 a perspective view of an embodiment of the domestic appliance of the present application is shown;

[0029] Figure 2 a perspective view of a centrifugal fan is shown;

[0030] Figure 3 a further perspective view of the centrifugal fan of Figure 2 is shown;

[0031] Figure 4 a schematic cross-sectional view of a centrifugal fan of the prior art is shown;

[0032] Figure 5 a schematic cross-sectional view of a first embodiment of a centrifugal fan of the present application is shown;

[0033] Figure 6 a partial view of the centrifugal fan of Figure 5 is shown;

[0034] Figure 7a schematic cross-sectional view showing a second embodiment of the centrifugal fan of the present application; and

[0035] Figure 8 a schematic cross-sectional view showing a third embodiment of the centrifugal fan of the present application.

[0036] List of reference signs

[0037] 1 household appliance

[0038] 2 centrifugal fan

[0039] 3 clothes treatment tub

[0040] 4 casing

[0041] 21 volute

[0042] 22 impeller

[0043] 23 driving device

[0044] 24 first backflow prevention portion

[0045] 25 second backflow prevention portion

[0046] 26 gap

[0047] 211 first housing

[0048] 212 second housing

[0049] 213 accommodation space

[0050] 221 impeller inlet

[0051] 222 impeller outlet

[0052] 223 first edge

[0053] 224 second edge

[0054] 231 driving shaft

[0055] A air flow direction

[0056] L backflow direction

[0057] XYZ XYZ coordinate system. DETAILED DESCRIPTION

[0058] In order to make the technical problems to be solved by the present application, the technical solutions and the beneficial technical effects more clearly understood, the present application will be further described in detail below in conjunction with the drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the protection scope of the present application.

[0059] For a better understanding of the above-mentioned centrifugal fan and the household appliance, exemplary embodiments of the present application will be described below with reference to the accompanying drawings. It is to be noted that the directional terms used in the description refer to the conventional use of the household appliance, e.g. a laundry-drying machine, and are used for the sake of description only and are not to be construed as an absolute limitation of the respective features.

[0060] Figure 1 A perspective view of one embodiment of the household appliance 1 of the present application is shown. The household appliance 1 is configured as a laundry treatment appliance, e.g. a drying machine or a laundry-drying machine, and comprises a centrifugal fan 2, a laundry treatment tub 3 and a casing 4.

[0061] For the sake of clarity, an XYZ coordinate system is exemplarily indicated in Figure 1 , wherein the X direction exemplarily represents a user-facing direction of the household appliance 1, the Y direction exemplarily represents a lateral direction of the household appliance 1 and the Z direction exemplarily represents a vertical or height direction of the household appliance 1.

[0062] As shown in Figure 1 , the laundry treatment tub 3 is arranged in the casing 4 and is configured to accommodate laundry to be treated. The centrifugal fan 2 is exemplarily arranged above the laundry treatment tub 3 in the Z direction in the casing 4 and is in fluid communication with the laundry treatment tub 3 via an air passage. Since other structural components of the household appliance 1, e.g. door bodies, panels, conduits, etc. are not the focus of the present application, they are not indicated and described in detail here.

[0063] Figure 2 A perspective view of the centrifugal fan 2 is shown. Figure 3 Another perspective view of the centrifugal fan 2 in Figure 2 is shown.

[0064] The centrifugal fan 2 comprises a volute 21, which forms an accommodation space 213. Further, the centrifugal fan 2 comprises an impeller 22, which is rotatably accommodated in the accommodation space 213 of the volute 21 for sucking in air and accelerating and pressurizing it. The centrifugal fan 2 further comprises a drive device 23, which is exemplarily configured as a drive motor. The impeller 22 is arranged anti-torsionally on a drive shaft 231 of the drive motor and is driven into rotational movement by the drive shaft 231.

[0065] The impeller 22 comprises an impeller inlet 221 and an impeller outlet 222. In operation of the household appliance 1, air enters the impeller 22 via the impeller inlet 221 in the Z direction and flows out of the impeller outlet 222 in a circumferential direction into the air passage of the volute 21 and is guided via the air passage into the laundry treatment tub 3 (see also Figure 1 ).

[0066] Figure 4A schematic cross-sectional view of a centrifugal fan 2 in the prior art is shown.

[0067] In combination Figures 1 to 3 , in Figure 4 , the volute 21 is two-piece constructed and comprises a first casing 211 and a second casing 212. The first casing 211 and the second casing 212 are connected to each other, for example, are plugged into each other or are connected to each other by screws, etc., and form an accommodation space 213 for accommodating the impeller 22. The drive device 23 is arranged on the first casing 211 in the Z direction. A drive shaft 231 of the drive device 23 extends through the volute 21 or the first casing 211 in the Z direction. The impeller 22 is connected to the drive shaft 231 in a torsion-proof manner and can be driven by the drive device 23 to perform a rotational movement in the accommodation space 213.

[0068] Air is sucked from an impeller inlet 221 of the impeller 22 located in the middle of the bottom and is accelerated and pressurized along the blade of the impeller 22. Due to the centrifugal effect, the air is guided (or "flung") in the impeller 22 to an impeller outlet 222 constructed in the circumferential direction of the impeller 22 and flows out of the impeller outlet 222, as indicated by the air flow direction A in Figure 4 . Thus, the pressure of the air at the impeller outlet 222 is greater than the pressure of the air at the impeller inlet 221.

[0069] In Figure 4 the drawing plane, the impeller 22 rotates relative to the volute 21, and there is a gap 26 between the impeller 22 and the second casing 212. Thus, part of the higher pressure air flowing out of the impeller outlet 222 will flow along this gap 26 in the direction of the impeller inlet 221, as indicated by the backflow direction L in Figure 4 . This not only causes the amount of air introduced into the laundry treatment tub 3 to decrease, but the air backflowing to the impeller inlet 221 also meets the air sucked from the impeller inlet 221 in a different direction, which also causes air flow interference at the impeller inlet 221. As a result, not only does the efficiency of the centrifugal fan 2 decrease and the energy consumption increases, but problems such as poor drying effect and long drying time can also be caused, which will affect the user experience and satisfaction.

[0070] In the following, various embodiments of the present application are described in detail in combination with Figures 5 to 6 .

[0071] Figure 5 A schematic cross-sectional view of a first embodiment of the centrifugal fan 2 of the present application is shown. Figure 6 A partial view of the centrifugal fan 2 of Figure 5 is shown. For the sake of brevity, repeated descriptions of the same structures and arrangements of the centrifugal fan 2 in Figure 5 and Figure 6 are omitted.

[0072] According to the present application, at least one first backflow prevention portion 24 is configured at the area adjacent to the impeller 22 and the volute 21 along the air flow direction A in the impeller 22 at the impeller inlet 221, which at least partially prevents the air flowing out of the impeller outlet 222 from flowing back toward the impeller inlet 221.

[0073] Unlike Figure 4 , in the first embodiment, the first backflow prevention portion 24 is arranged on the volute 21 only near the first edge 223 of the impeller outlet 222 and extends toward the radially outer side of the first edge 223 of the impeller outlet 222.

[0074] As shown in Figure 5 and Figure 6 , the first backflow prevention portion 24 is arranged outside the first edge 223 of the impeller outlet 222 along the radial direction of the impeller 22 and is configured as a protrusion extending continuously in the circumferential direction. The protrusion at least partially blocks the flow of air toward the impeller inlet 221 via the gap 26. Thus, the high-pressure air flowing out of the impeller outlet 222 can be reliably prevented from flowing back to the impeller inlet 221 along the gap 26 without occupying the space below the second edge 224 of the impeller inlet 221, thereby improving the efficiency of the centrifugal fan 2 and reducing energy consumption.

[0075] According to one embodiment, the first backflow prevention portion 24 is arranged, for example, integrally formed on the second housing 212 and configured at least flush with the first edge 223 of the impeller outlet 222 near the second housing 212 in the air flow direction in the state that the impeller 22 is accommodated in the accommodation space 213. That is, in Figure 5 and Figure 6 , the first backflow prevention portion 24 is substantially at the same height as the first edge 223 in the Z direction. Therefore, at the impeller outlet 222, the first edge 223 and the upper side of the first backflow prevention portion 24 form a consistent, approximately continuous (except for the gap 26) running direction, so that the air flowing out of the impeller outlet 222 continues to flow along the upper side of the first backflow prevention portion 24 almost unimpeded. This can improve the flowability of the air at the impeller outlet 222 and ensure the consistent running direction of the air flow, thereby improving the efficiency of the centrifugal fan 2.

[0076] Figure 7 A schematic cross-sectional view of a second embodiment of the centrifugal fan 2 of the present application is shown. Unlike Figure 5 and Figure 6In the second embodiment, a second backflow prevention portion 25 adapted to at least partially prevent the air flowing out of the impeller outlet 222 from flowing in the direction of the impeller inlet 221 via the gap 26 is configured along the direction of the air flowing in the impeller 22, in addition to the first backflow prevention portion 24 configured on the second housing 212 near the impeller outlet 222.

[0077] According to the second embodiment, the second backflow prevention portion 25 is arranged, for example, integrally formed, on the portion of the second housing 212 near the impeller inlet 221 in a circumferential direction. As shown in Figure 7 the second backflow prevention portion 25 protrudes from the radially inner side of the second edge 224 of the impeller inlet 221 and forms a hook-like structure. Therefore, by additionally providing the second backflow prevention portion 25, the high-pressure air flowing out of the impeller outlet 222 can be more reliably prevented from flowing back along the gap 26 to the impeller inlet 221, thereby further improving the efficiency of the centrifugal fan 2 and reducing energy consumption.

[0078] Figure 8 A schematic sectional view of a third embodiment of the centrifugal fan 2 of the present application is shown. Similarly to the Figure 7 embodiment, in the third embodiment, a second backflow prevention portion 25 adapted to at least partially prevent the air flowing out of the impeller outlet 222 from flowing in the direction of the impeller inlet 221 via the gap 26 is configured along the direction of the air flowing in the impeller 22 near the impeller inlet 221. The second backflow prevention portion 25 is arranged, for example, integrally formed, on the second housing 212. However, unlike the Figure 7 embodiment, as shown in Figure 8 the second backflow prevention portion 25 is configured to be flush with the lower side of the second edge 224 of the impeller inlet 221 in the Z direction in the state where the impeller 22 is accommodated in the accommodation space 213. That is, the second backflow prevention portion 25 is configured as a protrusion protruding in the Y direction toward the second edge 224 in the drawing plane of Figure 8 and the protrusion does not exceed (does not fall below) the lower side of the second edge 224 in the Z direction. Thereby, without occupying the space below the second edge 224 of the impeller inlet 221 while preventing the backflow of air and thus ensuring the efficiency of the centrifugal fan 2, the space between the centrifugal fan 2 and the laundry treatment tub 3 is not partially occupied by the second backflow prevention portion 25 when the centrifugal fan 2 is arranged above the laundry treatment tub 3, so that no interference between components due to the second backflow prevention portion 25 occurs when other functional components are arranged in the space below the second edge 224 of the impeller inlet 221 of the centrifugal fan 2.

[0079] The technical solution of the present application is exemplarily applied in a clothes dryer or a washer-dryer. However, the application of the technical solution of the present application in other household appliances can also be considered.

[0080] Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even if only a single embodiment is described with respect to a particular feature. The examples of features provided in the present disclosure are intended to be illustrative rather than limiting, unless expressly stated otherwise. In practice, a plurality of features can be combined with each other, as technically feasible, according to actual needs. Various substitutions, modifications and changes can also be conceived without departing from the spirit and scope of the present disclosure.

Claims

1. A centrifugal fan for a domestic appliance, characterized in that, The centrifugal fan (2) includes: a volute (21) that forms an accommodation space; an impeller (22) rotatably accommodated in the accommodation space (213) of the volute (21) for sucking and accelerating air, wherein the impeller (22) includes an impeller inlet (221) and an impeller outlet (222) through which air enters and flows out, respectively; wherein, at a region adjacent to the volute (21) of the impeller (22), at least one first anti-backflow portion (24) adapted to at least partially prevent the air flowing out of the impeller outlet (222) from flowing back toward the impeller inlet (221) is configured in a direction (A) in which air flows in the impeller (22) at a position away from the impeller inlet (221).

2. The centrifugal fan of claim 1, wherein In a state where the impeller (22) is arranged in the accommodation space (213), a gap (26) is formed between the impeller (22) and an inner wall of the volute (21), and the first anti-backflow portion (24) at least partially prevents air from flowing toward the impeller inlet (221) via the gap (26).

3. The centrifugal fan according to claim 2, wherein the first anti-backflow portion (24) is arranged close to a first edge (223) of the impeller outlet (222).

4. The centrifugal fan according to claim 3, wherein the first anti-backflow portion (24) is provided on the volute (21) and extends radially outward of the first edge (223) of the impeller outlet (222).

5. The centrifugal fan according to claim 4, wherein the first anti-backflow portion (24) is continuously distributed in a circumferential direction.

6. The centrifugal fan according to claim 2 or 3, characterized in that the volute (21) includes a first casing (211) and a second casing (212) that are connected to each other and form the accommodation space (213) for accommodating the impeller (22), and the gap (26) is formed between the impeller (22) and the second casing (212), wherein the first anti-backflow portion (24) is arranged on the second casing (212) and is configured to be at least flush with the first edge (223) of the impeller outlet (222) close to the second casing (212) in the flow direction of air in a state where the impeller (22) is accommodated in the accommodation space (213).

7. The centrifugal fan of claim 6, wherein the first anti-backflow portion (24) is arranged radially outward of the first edge (223) of the impeller outlet (222) of the impeller (22); and / or the first anti-backflow portion (24) is configured as a protrusion that continuously extends in a circumferential direction and at least partially blocks the flow of air toward the impeller inlet (221) via the gap (26).

8. The centrifugal fan of claim 6, wherein In the direction of the air flow in the impeller (22), a second backflow prevention portion (25) is also configured near the impeller inlet (221), which is adapted to at least partially prevent the air flowing out of the impeller outlet (222) from flowing in the direction of the impeller inlet (221) via the gap (26).

9. The centrifugal fan according to claim 8, characterized in that The second backflow prevention portion (25) is arranged on the second housing (212) and is configured to be flush with the lower side of the second edge (224) of the impeller inlet (221) in the vertical direction (Z) in the state that the impeller (22) is accommodated in the accommodation space (213).

10. The centrifugal fan according to claim 8, characterized in that The second backflow prevention portion (25) protrudes from the radially inner side of the second edge (224) of the impeller inlet (221).

11. A household appliance characterized in that, The household appliance (1) comprises a centrifugal fan (2) according to one of claims 1 to 10.

12. The household appliance according to claim 11, characterized by The household appliance (1) is a laundry-drying machine, which comprises a laundry treatment tub (3), and the centrifugal fan (2) is located above the laundry treatment tub (3), and the first backflow prevention portion (24) is arranged only near the impeller outlet (222).

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