Mixed flow fan and ducted fan

Abstract

The application provides a mixed flow fan and a ducted fan to solve the problem of large noise of the mixed flow fan in the prior art. The mixed flow fan comprises a volute, an impeller arranged in the volute, and an inner shell arranged in the volute and having a sound absorbing cavity formed inside. The mixed flow fan and the ducted fan provided by the application have the inner shell arranged inside the mixed flow fan and the sound absorbing hole arranged on the inner shell, so that the airflow inside the mixed flow fan is communicated with the inside of the inner shell to form a sound absorbing cavity inside the inner shell. When the mixed flow fan is working, the sound absorbing hole converts a part of low-frequency noise into high-frequency noise when the high-speed airflow passes through the inner shell, and the high-frequency noise is offset by the noise generated by the airflow of the fan to achieve the sound absorbing effect. Moreover, the sound absorbing structure (sound absorbing cotton) arranged inside the inner shell dilutes and eliminates the high-frequency noise entering the sound absorbing cavity, thereby increasing the sound absorbing effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air treatment equipment, in particular to a mixed flow fan and ducted air conditioner. BACKGROUND

[0002] The ducted air conditioner is a kind of air conditioner, in order to improve the comfort, some ducted air conditioners adopt the mode of upper cold air and lower hot air, which can realize waterfall type refrigeration and carpet type warm air, in order to realize this air outlet mode, the air outlet of the ducted air conditioner needs to be reversible, in the existing air outlet reversible ducted air conditioner, a tubular fan and a centrifugal fan are usually adopted, but due to the setting mode of the fan blades, the air direction cannot be reversed after reversing, therefore, at least two fans need to be set, one is responsible for forward air outlet and the other is responsible for reverse air outlet, which not only makes the structure of the ducted air conditioner larger, but also increases the cost.

[0003] In order to reduce the cost, the fan needs to be reduced, and the mixed flow fan is a fan between the axial flow fan and the centrifugal fan, the impeller of the mixed flow fan makes the air do both centrifugal motion and axial motion, the airflow in the volute is mixed with axial flow and centrifugal motion, so it is called "mixed flow". Moreover, the mixed flow fan can not only be small in size, but also can ensure the flow direction and air pressure of the airflow.

[0004] However, the existing mixed flow fan has poor noise reduction effect, which causes the problem of large noise of the mixed flow fan. SUMMARY

[0005] The embodiments of the present application provide a mixed flow fan and a ducted air conditioner to solve the problem of large noise of the mixed flow fan in the prior art.

[0006] A mixed flow fan, comprising:

[0007] A volute;

[0008] An impeller arranged in the volute;

[0009] An inner shell arranged in the volute, and an inner cavity formed in the inner shell.

[0010] An annular air duct is formed between the outer surface of the inner shell and the inner surface of the volute, and a through hole is arranged on the inner shell and communicates the inner cavity and the annular air duct.

[0011] A guide vane is arranged in the annular air duct.

[0012] The diameter R of the through hole is 0.05 to 0.2 times the height H of the guide vane.

[0013] The inner cavity is filled with a noise reduction structure.

[0014] The distance from the sound-damping structure to the impeller is less than the minimum distance from the through hole to the impeller.

[0015] The mixed-flow fan further comprises an impeller driving mechanism arranged in the inner shell, and an output shaft of the impeller driving mechanism protruding from the inner shell, and the impeller is arranged on the output shaft.

[0016] The impeller driving mechanism further comprises a protective cover, and an outer surface of the protective cover and an inner surface of the inner shell form the sound-damping cavity.

[0017] An outer surface of the protective cover is provided with sound-damping material.

[0018] A ducted fan comprises the mixed-flow fan.

[0019] The mixed-flow fan and the ducted fan provided by the present application have the following advantages: the inner shell is arranged in the mixed-flow fan, and a sound-damping hole is arranged on the inner shell, so that the airflow in the mixed-flow fan is communicated with the inside of the inner shell, and a sound-damping cavity is formed in the inner shell; when the mixed-flow fan is working, the sound-damping hole converts a part of low-frequency noise into high-frequency noise, and the high-frequency noise is offset by the noise generated by the airflow of the fan, so that the noise is damped; and the sound-damping structure (sound-damping cotton) arranged in the inner shell dilutes and eliminates the high-frequency noise entering the sound-damping cavity, so that the sound-damping effect is increased. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 A sectional view of the mixed-flow fan provided by the embodiment of the present application;

[0021] Fig. 2 A structural schematic view of the inner shell and the guide vane provided by the embodiment of the present application;

[0022] Fig. 3 Another structural schematic view of the inner shell and the guide vane provided by the embodiment of the present application;

[0023] In the drawings:

[0024] 1, volute; 2, impeller; 4, inner shell; 5, sound-damping cavity; 41, through hole; 33, guide vane; 6, impeller driving mechanism; 61, protective cover. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0026] The mixed flow fan forms a wind channel inside the shell, and sets an impeller in the wind channel, and the gas outside the shell is sucked into the wind channel and discharged from the wind channel through the rotation of the impeller, and noise is generated in the flow process of the gas, so that the noise of the mixed flow fan increases, and the prior art is to set a separate sound attenuation structure at the air inlet or air outlet of the mixed flow fan for sound attenuation and noise reduction, without considering improving the structure of the mixed flow fan for sound attenuation. After the inventor's research and analysis of simulation experimental data, it is found that the sound attenuation design inside the shell of the mixed flow fan is an improvement point for effectively improving the noise of the mixed flow fan.

[0027] Therefore, in order to avoid the additional setting of the sound attenuation structure outside the mixed flow fan, the noise of the mixed flow fan is reduced, such as Figs. 1 to 3 The mixed flow fan shown in the figure comprises a volute 1, an impeller 2 arranged in the volute 1, and an inner shell 4 arranged in the volute 1, and an inner shell 4 is formed inside the inner shell 4. By arranging the inner shell 4 inside the mixed flow fan, the airflow inside the mixed flow fan is communicated with the inside of the inner shell 4 to form an inner shell 4 inside the inner shell 4. When the mixed flow fan works, the high-speed airflow passes through the inner shell 4, and the sound attenuation hole will convert part of the low-frequency noise into high-frequency noise, and offset the noise generated by the airflow of the fan to achieve the effect of sound attenuation.

[0028] The outer surface of the inner shell 4 and the inner surface of the volute 1 form an annular wind channel, and the inner shell 4 is provided with a through hole 41 communicating the sound attenuation cavity 5 and the annular wind channel. Preferably, the inner shell 4 is arranged on one side of the impeller 2, and the airflow blown out by the impeller 2 can be discharged from the volute 1 through the annular wind channel. It can also be said that the through hole 41 on the inner shell 4 and the sound attenuation cavity 5 formed inside the inner shell 4 can cooperate with the air outlet of the impeller 2 (the gas about to be discharged by the mixed flow fan) to attenuate the noise, thereby achieving the purpose of reducing the noise of the mixed flow fan.

[0029] The annular wind channel is provided with a guide vane 33, which can guide the airflow in the annular wind channel (also known as the air outlet of the impeller 2) to improve the air outlet effect of the mixed flow fan.

[0030] The diameter R of the through hole 41 is 0.05 to 0.2 times the height H of the guide vane 33. The height H of the guide vane 33 refers to the size of the guide vane 33 in the axial direction of the impeller 2, and the guide vane 33 can be determined according to the size of the inner shell 4. Under the condition of ensuring the volume of the sound attenuation cavity 5, the higher the height of the inner shell 4, the greater the height H of the guide vane 33, and at this time, the maximum diameter of the inner shell 4 is also smaller, and the resistance of the wind channel in the volute 1 to the airflow is smaller. On the contrary, the smaller the height of the inner shell 4, the smaller the height H of the guide vane 33, and at this time, the maximum diameter of the inner shell 4 is also larger, and the resistance of the wind channel in the volute 1 to the airflow is larger.

[0031] The inventor has found through research and simulation experiment data analysis that in the process of sound attenuation of the through hole 41 and the sound attenuation cavity 5 to the mixed flow fan, the diameter of the through hole 41 is actually an important size affecting the sound attenuation effect. Simulation tests are conducted on the mixed flow fan in this example, the range of R / H is changed, and the simulation results are as follows:

[0032]

[0033] From the above results, it can be seen that when R / H is 0.12, the air volume reaches the maximum value, the internal power and the noise reach the minimum value, when R / H increases to 0.20, the air volume begins to decrease, the internal power and the noise begin to increase, when R / H continues to increase to 0.22, the air volume continues to decrease, the internal power and the noise continue to increase, that is, the increase of R / H is not conducive to the air volume and the noise of the mixed flow fan; when R / H decreases to 0.05, the air volume begins to decrease, the internal power and the noise begin to increase, when R / H continues to decrease to 0.01, the air volume continues to decrease, although the internal power does not change compared with R / H of 0.05, but the noise is still increasing, that is, under the condition of the same impeller 2 rotating speed, when the value of R / H is too large, the noise reduction effect of the mixed flow fan is not good, and the diameter of the through hole 41 is too large or the height of the guide vane 33 is too small, which will affect the smoothness of the air duct in the volute 1, and is not conducive to the flow of gas, but will cause additional noise, but when the diameter of the through hole 41 is too small, the through hole 41 cannot produce the noise reduction effect on the airflow, therefore, selecting a suitable value of R / H can better achieve the noise reduction effect of the mixed flow fan.

[0034] The sound attenuation cavity 5 is filled with a sound attenuation structure. The sound attenuation structure is preferably sound attenuation cotton, which can further increase the noise reduction effect of the mixed flow fan by diluting and eliminating the noise inside the sound attenuation cavity 5.

[0035] The distance from the sound attenuation structure to the impeller 2 is less than the minimum distance from the through hole 41 to the impeller 2. That is, the sound attenuation structure can cover all positions inside the inner shell 4 where the through hole 41 exists, so as to ensure that the sound attenuation structure can dilute and eliminate the noise introduced by all through holes 41, and maximize the noise reduction effect of the mixed flow fan.

[0036] The mixed flow fan further comprises an impeller driving mechanism 6, the impeller driving mechanism 6 is arranged in the inner shell 4, the output shaft of the impeller driving mechanism 6 protrudes from the inner shell 4, and the impeller 2 is arranged on the output shaft. By arranging the impeller driving mechanism 6 in the inner shell 4, the volume of the mixed flow fan can be reduced as much as possible. Preferably, the impeller driving mechanism 6 is an electric motor.

[0037] The impeller driving mechanism 6 further comprises a protective cover 61, an outer surface of the protective cover 61 and an inner surface of the inner shell 4 form the soundproofing cavity 5. The airflow of the mixed-flow fan and the impeller driving mechanism 6 are prevented from affecting each other by the protective cover 61.

[0038] An outer surface of the protective cover 61 is provided with soundproofing material, which further increases the noise reduction effect of the mixed-flow fan.

[0039] A ducted fan machine comprises the mixed-flow fan described above.

[0040] The edge of the guide vane 33 is provided with soundproofing teeth.

[0041] The guide vane 33 is provided with protrusions and / or pits.

[0042] The above-mentioned embodiments only express several embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A mixed-flow fan, characterized in that: include: Snail shell (1); Impeller (2), the impeller (2) is disposed inside the volute (1); Inner shell (4), the inner shell (4) is disposed inside the volute (1), and a sound-absorbing cavity (5) is formed inside the inner shell (4). An annular air duct is formed between the outer surface of the inner shell (4) and the inner surface of the volute. The inner shell (4) is provided with a through hole (41) connecting the silencing cavity (5) and the annular air duct. The annular air duct is equipped with guide vanes (33). The diameter R of the through hole (41) is 0.05 to 0.2 times the height H of the guide vane (33); The height H of the guide vane (33) refers to the size of the guide vane (33) in the axial direction of the impeller (2).

2. The mixed-flow fan according to claim 1, characterized in that: The silencing cavity (5) is filled with a silencing structure.

3. The mixed-flow fan according to claim 2, characterized in that: The distance from the silencing structure to the impeller (2) is less than the minimum distance from the through hole (41) to the impeller (2).

4. The mixed-flow fan according to claim 1, characterized in that: The mixed-flow fan also includes an impeller drive mechanism (6), which is disposed inside the inner shell (4), and the output shaft of the impeller drive mechanism (6) protrudes from the inner shell (4), and the impeller (2) is disposed on the output shaft.

5. The mixed-flow fan according to claim 4, characterized in that: The impeller drive mechanism (6) also includes a protective cover (61), the outer surface of the protective cover (61) and the inner surface of the inner shell (4) forming the silencing cavity (5).

6. The mixed-flow fan according to claim 5, characterized in that: The outer surface of the protective cover (61) is provided with sound-absorbing material.

7. A ducted air conditioner, characterized in that: Includes the mixed-flow fan as described in any one of claims 1 to 6.

Images