Centrifugal fan

Abstract

A centrifugal fan comprises a volute assembly which comprises a front cover and a shell, the front cover is provided with a main air inlet and is arranged on the front side of the centrifugal fan, and the shell is provided with an air outlet; the motor assembly comprises a motor and an output shaft, the motor is fixed to the shell and arranged on the rear side of the centrifugal fan, and the output shaft extends into the volute assembly; the impeller assembly comprises a front plate, a back plate and main blades, the front plate is arranged on the front side relative to the back plate, the back plate is provided with an auxiliary air inlet, the main blades are located between the front plate and the back plate, the main blades are configured to suck air from the main air inlet, and the impeller assembly is configured to rotate under the action of the output shaft; the impeller assembly comprises a main flow channel and an auxiliary flow channel, the main flow channel communicates with the main air inlet and the air outlet, the auxiliary flow channel communicates with the auxiliary air inlet and the air outlet, and the main flow channel and the auxiliary flow channel are at least partially spaced.

Description

Technical Field

[0001] The present invention relates to a centrifugal fan, and more particularly to a leakage-proof centrifugal fan. Background Art

[0002] The centrifugal fan draws in air through the impeller and does work on the air to generate high-pressure air. Because the output shaft of the motor drives the impeller to rotate, there is generally a gap between the output shaft of the motor and the housing. Although a seal can be set between the output shaft and the housing, after long-term operation, the seal may become less effective due to aging and wear, causing some airflow to leak. The gas at the rear of the centrifugal fan is connected to the gas that has been worked on by the impeller at the periphery of the impeller, resulting in a positive pressure state at the rear of the centrifugal fan. The positive pressure state can easily cause the gas to leak through the output shaft of the motor to the outside of the centrifugal fan, causing certain safety hazards.

[0003] In the prior art, in order to solve the technical problem caused by the above-mentioned airflow leakage, auxiliary blades are arranged on the rear side of the impeller, and the auxiliary blades inhale the leaked airflow on the rear side of the centrifugal fan, so that the rear side of the centrifugal fan is in a negative pressure state, so as to improve the problem of airflow leakage. However, the airflows generated by the main blades and the auxiliary blades interfere with each other. On the one hand, the main airflow generated by the main blades will weaken the negative pressure effect on the rear side of the impeller, and on the other hand, the secondary airflow generated by the auxiliary blades will also weaken the high-pressure airflow generated by the main blades, thereby adversely affecting the performance of the centrifugal fan.

[0004] Therefore, it is desired to provide a centrifugal fan to improve the defects in the above-mentioned prior art. Summary of the invention

[0005] According to one aspect of the present invention, a centrifugal fan is proposed, comprising: a volute assembly, comprising a front cover and a shell, the front cover having a main air inlet and arranged on the front side of the centrifugal fan, and the volute assembly having an air outlet; a motor assembly, comprising a motor and an output shaft, the motor being fixed to the shell and arranged on the rear side of the centrifugal fan, and the output shaft extending to the interior of the volute assembly; an impeller assembly, comprising a front plate, a back plate and main blades, the front plate being arranged on the front side relative to the back plate, the back plate having a secondary air inlet, the main blades being located between the front plate and the back plate, the main blades being configured to inhale gas from the main air inlet, and the impeller assembly being configured to rotate under the action of the output shaft; wherein the impeller assembly comprises a main flow channel and a secondary flow channel, the main flow channel connecting the main air inlet and the air outlet, the secondary flow channel connecting the secondary air inlet and the air outlet, and the main flow channel is at least partially separated from the secondary flow channel.

[0006] According to this solution, by at least partially separating the main flow channel from the secondary flow channel, mutual interference between the main airflow generated by the main blades and the secondary airflow generated by the secondary blades is avoided, thereby improving the performance of the centrifugal fan.

[0007] In some aspects, the impeller assembly may further include a wind baffle disposed between the primary flow channel and the secondary flow channel to at least partially separate the primary flow channel from the secondary flow channel.

[0008] According to this solution, the wind baffle can separate the primary airflow generated by the main blades from the secondary airflow generated by the secondary blades, thereby avoiding the primary airflow and the secondary airflow from colliding with each other and interfering with each other.

[0009] In some solutions, the wind shield may have a disc shape and extend outward from the central axis to the main blades in the radial direction, the main flow channel is located at the front side of the wind shield, and the secondary flow channel is located at the rear side of the wind shield.

[0010] In some schemes, a groove concave toward the front side may be formed on the back plate, the groove having a groove bottom plate and a groove side plate, the groove bottom plate faces the back plate, the groove side plate extends from the groove bottom plate to the back plate, and a plurality of through groove openings are opened on the groove side plate, the through groove openings form a secondary flow channel.

[0011] According to this solution, the concave structure can be manufactured through a process without increasing the material, and the concave structure forms a secondary flow channel, thereby reducing the cost of the centrifugal fan.

[0012] In some aspects, the groove side panels may extend in a direction perpendicular to the back panel.

[0013] In some embodiments, a secondary blade may be provided on the groove bottom plate, and the secondary blade is configured to suck gas from the secondary air inlet.

[0014] In some aspects, the secondary blades may extend from the groove floor to the inside of the backing plate.

[0015] According to this solution, the height of the auxiliary blades does not exceed the back plate, which is conducive to the miniaturization of the centrifugal fan.

[0016] In some solutions, the auxiliary blade can be turned out from the groove bottom plate through the material at the through-slot.

[0017] In some aspects, the groove side plates may extend from the groove bottom plate in a radially outward direction to the back plate.

[0018] According to this solution, the inclined groove side panel facilitates the formation of an air inlet at the opening of the groove side panel, and the concave shape facilitates the gathering of the airflow from the rear side of the back panel, so that additional auxiliary blades are no longer required, making the structure of the centrifugal fan simpler and reducing costs.

[0019] In some embodiments, the groove side plate can be configured to draw air from the secondary air inlet.

[0020] In some solutions, the through slots may extend through the groove side panels to the inner side of the back panel.

[0021] In some embodiments, the wind baffle can be aligned with the groove floor.

[0022] In some solutions, the wind shield, the groove bottom plate and the back plate may be respectively provided with axial holes aligned with each other, and the axial holes are aligned with the output shaft.

[0023] In some aspects, the wind baffle may be secured to the output shaft by a nut.

[0024] In some embodiments, the impeller assembly may include: a main impeller, configured to suck in gas from a main air inlet, a front plate formed as a front shell of the main impeller, and a main flow channel located in the main impeller; a secondary impeller, arranged on the rear side of the main impeller and configured to suck in gas from a secondary air inlet, a secondary flow channel located in the secondary impeller, and a back plate formed as a rear shell of the secondary impeller.

[0025] According to this solution, the flow passage of the main impeller and the flow passage of the auxiliary impeller are isolated from each other, thereby preventing the mutual interference between the airflow generated by the main impeller and the airflow generated by the auxiliary impeller.

[0026] In some solutions, the rear side casing of the main impeller can be fitted together with the front side casing of the auxiliary impeller.

[0027] In some aspects, the main impeller and the auxiliary impeller may be closed impellers.

[0028] In some solutions, the height of the auxiliary impeller in the axial direction may be between 1 / 4 and 1 / 2 of the height of the main impeller in the axial direction.

[0029] In some solutions, the height of the auxiliary impeller in the axial direction may be 1 / 3 of the height of the main impeller in the axial direction.

[0030] In some solutions, the centrifugal fan may further include a sealing gasket arranged between the output shaft and the housing.

[0031] In some solutions, the centrifugal fan may further include a sealing groove, which is arranged on the outer peripheral surface of the housing facing the front cover, and a sealing strip is placed in the sealing groove, and the sealing strip is used for sealing between the housing and the front cover.

[0032] According to this solution, a sealing strip is placed in the groove to prevent gas leakage through the contact surface, and can also assist in filling and sealing with sealant. The sealing strip and sealant can meet long-term sealing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 An external schematic diagram of a centrifugal fan according to an embodiment of the present invention is shown;

[0034] Figure 2 shows a cross-sectional view of a centrifugal fan according to a first embodiment of the present invention;

[0035] Figure 3 A schematic diagram of an impeller assembly according to a first embodiment of the present invention is shown;

[0036] Figure 4 shows a cross-sectional view of an impeller assembly according to a first embodiment of the present invention;

[0037] Figure 5 shows a cross-sectional view of a centrifugal fan according to a second embodiment of the present invention;

[0038] Figure 6 A schematic diagram of an impeller assembly according to a second embodiment of the present invention is shown;

[0039] Figure 7 shows a cross-sectional view of an impeller assembly according to a second embodiment of the present invention;

[0040] Figure 8 A cross-sectional view of a centrifugal fan according to a third embodiment of the present invention is shown.

[0041] Reference numerals:

[0042] 100 Centrifugal Fan

[0043] 110 Volute assembly

[0044] 112 front cover

[0045] 114 Housing

[0046] 116 Main air inlet

[0047] 118 Air outlet

[0048] 120 Motor assembly

[0049] 122 Motor

[0050] 124 Output shaft

[0051] 130 Impeller assembly

[0052] 131 front panel

[0053] 132 Back Panel

[0054] 133 Auxiliary air inlet

[0055] 134 Main blade

[0056] 135 Auxiliary blade

[0057] 136 Windshield

[0058] 137 Grooves

[0059] 137-B Grooved Base Plate

[0060] 137-S Grooved Side Panel

[0061] 138 Through slot

[0062] 142 Nut

[0063] 144 Gasket

[0064] 152 Sealing strip

[0065] 154 Sealing groove

[0066] 156 Gasket

[0067] 200 Centrifugal Fan

[0068] 212 front cover

[0069] 214 Shell

[0070] 216 Main air inlet

[0071] 222 Motor

[0072] 224 Output shaft

[0073] 230 Impeller Assembly

[0074] 231 front panel

[0075] 232 Backplane

[0076] 233 Auxiliary air inlet

[0077] 234 Main blade

[0078] 236 Windshield

[0079] 237 Groove

[0080] 237-B Grooved Base Plate

[0081] 237-S Grooved Side Panel

[0082] 238 Through slot

[0083] 242 Nut

[0084] 244 Gasket

[0085] 252 Sealing strip

[0086] 254 Seal groove

[0087] 256 Gasket

[0088] 300 Centrifugal Fan

[0089] 312 front cover

[0090] 314 Shell

[0091] 316 Main air inlet

[0092] 318 Air outlet

[0093] 322 Motor

[0094] 324 Output shaft

[0095] 331 Main impeller

[0096] 332 Front casing of main impeller

[0097] 333 Main impeller rear casing

[0098] 336 auxiliaries

[0099] 337 Front casing of auxiliary impeller

[0100] 338 Rear casing of auxiliary impeller

[0101] 339 Auxiliary air inlet

[0102] 352 Sealing Strip

[0103] 354 Seal groove

[0104] 356 Gasket

[0105] A1 Main airflow

[0106] A2 Auxiliary airflow

[0107] H1 Impeller height

[0108] H2 Groove Depth

[0109] H3 Main impeller height

[0110] H4 Expeller Height

[0111] D1 Main air inlet diameter

[0112] D2 Groove diameter DETAILED DESCRIPTION

[0113] In order to make the purpose, scheme and advantages of the technical solution of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the drawings of the specific embodiments of the present invention. Unless otherwise specified, the terms used herein have the usual meanings in the art. The same reference numerals in the drawings represent the same components.

[0114] For a clearer description, unless otherwise specified, the meanings of the directional nouns appearing in this article are as follows: the front side refers to the side close to the main air inlet, and the rear side refers to the side opposite to the front side.

[0115] Figure 1 The external schematic diagram of the centrifugal fan 100 according to an embodiment of the present invention is shown. The centrifugal fan 100 mainly includes a volute assembly 110, a motor assembly 120 and an impeller assembly 130 (such as Figure 2 and Figure 3 1 ). The volute assembly 110 forms the outer shell of the centrifugal fan 100, and the impeller assembly 130 is accommodated inside the volute assembly 110. The motor assembly 120 provides power for the centrifugal fan 100, and the impeller assembly 130 rotates under the action of the motor assembly 120. The impeller assembly 130 sucks airflow from the outside and performs work on the airflow to generate high-speed and high-pressure airflow.

[0116] The volute assembly 110 mainly includes a front cover 112 and a housing 114. The front cover 112 is arranged on the front side of the centrifugal fan 100, and the housing 114 is arranged on the rear side of the centrifugal fan 100 relative to the front cover 112. The front cover 112 and the housing 114 are installed in cooperation to form an internal space for accommodating the impeller assembly 130. Specifically, on the mating surface of the front cover 112 and the housing 114, a sealing groove 154 may be provided on the side of the housing 114, a sealing strip 152 is placed in the sealing groove 154, and a sealant may be applied in the sealing groove 154 for sealing connection between the front cover 112 and the housing 114.

[0117] The volute assembly 110 further includes a main air inlet 116 and an air outlet 118. The main air inlet 116 is located at the front side of the front cover 112 (e.g., Figure 1 The air outlet 118 is located on the side of the housing 114 (eg, Figure 1 The impeller assembly 130 sucks air from the main air inlet 116, performs work on the air, and discharges the high-pressure and high-speed air from the air outlet 118 of the centrifugal fan 100.

[0118] The motor assembly 120 includes a motor 122 and an output shaft 124. The motor 122 is arranged at the rear side of the centrifugal fan 100 (for example, Figure 1 The motor 122 is a motor 124 and a housing 114 (shown on the right side) and is fixed to the housing 114, and the output shaft 124 extends through the housing 114 to the interior of the volute assembly 110. The rotation output by the motor 122 is transmitted to the impeller assembly 130 via the output shaft 124, thereby driving the impeller assembly 130 to rotate. A sealing gasket 156 is arranged between the output shaft 124 and the housing 114 to seal the gap between the output shaft 124 and the housing 114.

[0119] The impeller assembly 130 mainly includes a front plate 131, a back plate 132 and a main blade 134. The front plate 131 is arranged at the front side relative to the back plate 132. A space for accommodating blades is formed between the front plate 131 and the back plate 132. The main blade 134 is fixed to the front plate 131 and the back plate 132. When the output shaft 124 of the motor assembly 120 drives the main blade 134 to rotate, the main blade 134 inhales airflow from the main air inlet 116. In this article, the airflow inhaled by the main blade 134 from the main air inlet 116 is referred to as the main airflow A1. While the main airflow A1 flows through the impeller assembly 130, a portion of the airflow enters the rear side of the impeller assembly 130 (i.e., the area between the back plate 132 and the housing 114). In order to prevent this part of the airflow from damaging the motor assembly 120, a secondary air inlet 133 is provided on the back plate 132, and the airflow leaked from the rear side of the impeller assembly 130 can flow back into the impeller assembly 130 from the secondary air inlet 133, and then be discharged from the centrifugal fan 100 from the air outlet 118 under the action of the blades. In other words, if there is no secondary air inlet 133, the leakage airflow on the rear side of the impeller assembly 130 is in a positive pressure state. In the case where the secondary air inlet 133 is provided, the leakage airflow on the rear side of the impeller assembly 130 is in a negative pressure state, thereby preventing the conveying gas (for example, inflammable and explosive gases such as fuel gas) from leaking to the outside of the centrifugal fan 100 through the output shaft 124. In addition, it is also avoided that the leakage of corrosive gases may cause damage to the motor assembly 120. In this article, the airflow sucked from the secondary air inlet 133 is referred to as the secondary airflow A2. The main air inlet 116 plays a major role in sucking air, and the auxiliary air inlet 133 plays an auxiliary role in sucking air, so the diameter D1 of the main air inlet 116 is greater than the diameter D2 of the auxiliary air inlet 133 .

[0120] A groove 137 that is recessed toward the front side is formed on the back plate 132 of the impeller assembly 130, and the groove 137 has a groove bottom plate 137-B and a groove side plate 137-S. The groove bottom plate 137-B faces the back plate 132, and the groove side plate 137-S extends from the groove bottom plate 137-B to the back plate 132, and the groove side plate 137-S can extend to the back plate 132 in a direction perpendicular to the back plate 132. Auxiliary blades 135 are arranged on the groove bottom plate 137-B, and a through slot 138 is opened on the groove side plate 137-S, and the through slot 138 passes through the inner side of the back plate 132 on the groove side plate 137-S. When the output shaft 124 of the motor assembly 120 drives the auxiliary blades 135 to rotate, the auxiliary blades 135 inhale air flow from the auxiliary air inlet 133. Optionally, as Figure 4 As shown, the depth H2 of the groove 137 may be between 1 / 4 and 1 / 2 of the total height H1 of the impeller assembly 130. Preferably, the depth H2 of the groove 137 may be 1 / 3 of the total height H1 of the impeller assembly 130. In addition, in order to ensure the exhaust function and structural strength of the auxiliary blades 135, the number of the through slots 138 and the auxiliary blades 135 should be set to 3 to 7, preferably, set to 5.

[0121] In order to prevent the main airflow A1 sucked from the main air inlet 116 by the main blade 134 and the secondary airflow A2 sucked from the secondary air inlet 133 by the secondary blade 135 from interfering with each other, a circular air baffle 136 is provided on the groove bottom plate 137-B, and the air baffle 136 at least partially separates the main airflow A1 from the secondary airflow A2. The air baffle 136, the groove bottom plate 137-B and the back plate 132 are respectively provided with mutually aligned shaft holes, and the shaft holes are aligned with the output shaft 124. When assembling the centrifugal fan 100, the output shaft 124 passes through the back plate 132, the groove bottom plate 137-B and the air baffle 136 from the rear side to the front side in sequence, and the plane of the air baffle 136 is in contact with the groove bottom plate 137-B, and the air baffle 136 is installed on the output shaft 124 through the nut 142 and the gasket 144, and the air baffle 136 extends outwardly to the main blade 134 in the radial direction. By providing the air baffle 136 , mutual interference between the primary airflow A1 and the secondary airflow A2 is avoided, thereby improving the performance of the centrifugal fan 100 .

[0122] Optionally, the main blade 134 can adopt a backward-inclined blade structure, and the main blade 134 extends to the periphery in the radial direction of the impeller assembly 130. One side of the inner side of the main blade 134 extends to the main air inlet 116 on the front plate 131 side, and the other side extends to the groove side plate 137-S on the back plate 132 side.

[0123] Optionally, the impeller assembly 130 can be manufactured by sheet metal, casting, welding, etc. Preferably, the impeller assembly 130 is manufactured by sheet metal, the groove 137 is formed by pressing on the back plate 132, and the auxiliary blade 135 is turned out from the groove bottom plate 137-B through the material at the through-slot 138. The height of the auxiliary blade 135 increases linearly from the minimum diameter to the maximum diameter, and the highest point does not exceed the inner side of the back plate 132. Preferably, the auxiliary blade 135 can be a straight blade. Alternatively, the shape of the through-slot 138 can also be adjusted to turn out the auxiliary blade 135 in a forward, backward or radial direction.

[0124] Figure 5 2 shows a cross-sectional view of a centrifugal fan 200 according to a second embodiment of the present invention. The centrifugal fan 200 mainly includes a volute assembly, a motor assembly and an impeller assembly 230 (eg, Figure 6 and Figure 7 2. The volute assembly forms the outer shell of the centrifugal fan 200, and the impeller assembly 230 is accommodated inside the volute assembly. The motor assembly provides power for the centrifugal fan 200, and the impeller assembly 230 rotates under the action of the motor assembly. The impeller assembly 230 sucks airflow from the outside and performs work on the airflow to generate high-speed and high-pressure airflow.

[0125] The volute assembly mainly includes a front cover 212 and a housing 214. The front cover 212 is arranged on the front side of the centrifugal fan 200, and the housing 214 is arranged on the rear side of the centrifugal fan 200 relative to the front cover 212. The front cover 212 and the housing 214 are installed in cooperation to form an internal space for accommodating the impeller assembly 230. Specifically, on the mating surface of the front cover 212 and the housing 214, a sealing groove 254 may be provided on the side of the housing 214, a sealing strip 252 is placed in the sealing groove 254, and a sealant may be applied in the sealing groove 254 for a sealed connection between the front cover 212 and the housing 214.

[0126] The volute assembly also includes a main air inlet 216 and an air outlet, wherein the main air inlet 216 is located at the front side of the front cover 212, and the air outlet 218 is located at the side of the housing 214. The impeller assembly 230 inhales airflow from the main air inlet 216, performs work on the airflow, and discharges high-pressure and high-speed airflow out of the centrifugal fan 200 from the air outlet.

[0127] The motor assembly includes a motor 222 and an output shaft 224. The motor 222 is arranged at the rear side of the centrifugal fan 200 and fixed to the housing 214. The output shaft 224 extends through the housing 214 to the inside of the volute assembly. The rotation output by the motor 222 is transmitted to the impeller assembly 230 via the output shaft 224, thereby driving the impeller assembly 230 to rotate. A sealing gasket 256 is arranged between the output shaft 224 and the housing 214 to seal the gap between the output shaft 224 and the housing 214.

[0128] The impeller assembly 230 mainly includes a front plate 231, a back plate 232 and a main blade 234. The front plate 231 is arranged at the front side relative to the back plate 232. A space for accommodating the main blade 234 is formed between the front plate 231 and the back plate 232. The main blade 234 is fixed to the front plate 231 and the back plate 232. When the output shaft 124 of the motor assembly drives the main blade 234 to rotate, the main blade 234 inhales airflow from the main air inlet 216. While the main airflow A1 flows through the impeller assembly 230, a part of the airflow will enter the rear side of the impeller assembly 230 (i.e., the area between the back plate 232 and the housing 214). In order to prevent this part of the airflow from damaging the motor assembly, a secondary air inlet 233 is provided on the back plate 232. The airflow leaked from the rear side of the impeller assembly 230 can flow back into the impeller assembly 230 from the secondary air inlet 233, and then be discharged from the centrifugal fan 200 from the air outlet under the action of the blades.

[0129] A groove 237 that is concave toward the front side is formed on the back plate 232 of the impeller assembly 230, and the groove 237 has a groove bottom plate 237-B and a groove side plate 237-S. The groove bottom plate 237-B faces the back plate 232, and the groove side plate 237-S extends from the groove bottom plate 237-B to the back plate 232. A through groove opening 238 is formed on the groove side plate 237-S, and the through groove opening 238 penetrates the inner side of the back plate 232 on the groove side plate 237-S.

[0130] Different from the centrifugal fan 100 of the first embodiment, in the centrifugal fan 200 of the second embodiment, the groove side plate 237-S extends to the back plate 232 in a direction inclined to the back plate 232. Specifically, in the direction toward the back plate 232, the groove side plate 237-S extends in a radially outward direction. In this way, when the groove side plate 237-S rotates with the impeller assembly 230, the inclined groove side plate 237-S facilitates the formation of an air inlet at the opening of the groove side plate 237-S, and the concave shape facilitates the gathering of the airflow from the rear side of the back plate 232, so that the auxiliary blades do not need to be arranged additionally, making the structure of the centrifugal fan 200 simpler and reducing the cost.

[0131] In order to prevent the mutual interference between the main airflow A1 sucked from the main air inlet 216 by the main blade 234 and the secondary airflow A2 sucked from the secondary air inlet 233 by the groove side plate 237-S, a circular air baffle 236 is provided on the groove bottom plate 237-B, and the air baffle 236 at least partially separates the main airflow A1 from the secondary airflow A2. When assembling the centrifugal fan 200, the output shaft 224 passes through the back plate 232, the groove bottom plate 237-B and the air baffle 236 from the rear side to the front side in sequence, and the plane of the air baffle 236 is in contact with the groove bottom plate 237-B, and the air baffle 236 is installed on the output shaft 224 by the nut 242 and the gasket 244, and the air baffle 236 extends outwardly to the main blade 234 in the radial direction. By providing the air baffle 236, the mutual interference between the main airflow A1 and the secondary airflow A2 is avoided, thereby improving the performance of the centrifugal fan 200.

[0132] Figure 8 A cross-sectional view of a centrifugal fan 300 according to a third embodiment of the present invention is shown, and the centrifugal fan 300 mainly includes a volute assembly, a motor assembly and an impeller assembly. The volute assembly forms the outer shell of the centrifugal fan 300, and the impeller assembly is accommodated inside the volute assembly. The motor assembly provides power for the centrifugal fan 300, and the impeller assembly rotates under the action of the motor assembly. The impeller assembly inhales airflow from the outside and performs work on the airflow to generate a high-speed and high-pressure airflow.

[0133] The volute assembly mainly includes a front cover 312 and a housing 314. The front cover 312 is arranged on the front side of the centrifugal fan 300, and the housing 314 is arranged on the rear side of the centrifugal fan 300 relative to the front cover 312. The front cover 312 and the housing 314 are installed in cooperation to form an internal space for accommodating the impeller assembly. Specifically, on the mating surface of the front cover 312 and the housing 314, a sealing groove 354 may be provided on the side of the housing 314, a sealing strip 352 is placed in the sealing groove 354, and a sealant may be applied in the sealing groove 354 for a sealed connection between the front cover 312 and the housing 314.

[0134] The volute assembly further includes a main air inlet 316 and an air outlet, wherein the main air inlet 316 is located at the front side of the front cover 312 and the air outlet is located at the side of the housing 314. The impeller assembly inhales airflow from the main air inlet 316, performs work on the airflow, and discharges high-pressure and high-speed airflow out of the centrifugal fan 300 from the air outlet.

[0135] The motor assembly includes a motor 322 and an output shaft 324. The motor 322 is arranged at the rear side of the centrifugal fan 300 and fixed to the housing 314. The output shaft 324 extends through the housing 314 to the inside of the volute assembly. The rotation output by the motor 322 is transmitted to the impeller assembly via the output shaft 324, thereby driving the impeller assembly to rotate. A sealing gasket 356 is arranged between the output shaft 324 and the housing 314 to seal the gap between the output shaft 324 and the housing 314.

[0136] The impeller assembly includes a main impeller 331 and an auxiliary impeller 336, which are placed back to back and fixed to the output shaft 324. The main impeller 331 sucks the main airflow A1 from the main air inlet 316 and discharges the main airflow A1 from the air outlet of the centrifugal fan 300, and the auxiliary impeller 336 sucks the auxiliary airflow A2 from the auxiliary air inlet 339 and discharges the auxiliary airflow A2 from the air outlet of the centrifugal fan 300. The auxiliary air inlet 339 is located at the rear side of the impeller assembly (i.e., the side close to the motor 322). The main impeller 331 has a front casing 332 of the main impeller and a rear casing 333 of the main impeller, the front casing 332 and the rear casing 333 form the boundary of the main impeller 331, and the secondary impeller 336 has a front casing 337 of the secondary impeller and a rear casing 338 of the secondary impeller, the front casing 337 and the rear casing 338 form the boundary of the secondary impeller 336, and the rear casing 333 of the main impeller can be fitted together with the front casing 337 of the secondary impeller. The flow channel of the main impeller 331 and the secondary impeller 336 are both closed impellers, and the flow channels of the main impeller 331 and the secondary impeller 336 are isolated from each other, preventing mutual interference between the main airflow A1 generated by the main impeller 331 and the secondary airflow A2 generated by the secondary impeller 336. Optionally, the height H4 of the secondary impeller 336 can be 1 / 3 of the height of the main impeller 331.

[0137] This document describes in detail several exemplary embodiments of the present invention with reference to preferred embodiments. However, it will be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations may be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the present invention may also be combined without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. A centrifugal fan, comprising: A volute assembly, comprising a front cover and a housing, wherein the front cover has a main air inlet and is arranged at the front side of the centrifugal fan, and the volute assembly has an air outlet; a motor assembly, comprising a motor and an output shaft, wherein the motor is fixed to the housing and arranged at the rear side of the centrifugal fan, and the output shaft extends into the interior of the volute assembly; An impeller assembly, comprising a front plate, a back plate and a main blade, wherein the front plate is arranged at the front side relative to the back plate, the back plate has a secondary air inlet, the main blade is located between the front plate and the back plate, the main blade is configured to inhale gas from the main air inlet, and the impeller assembly is configured to rotate under the action of the output shaft; Wherein, the impeller assembly comprises a main flow channel and a secondary flow channel, the main flow channel is connected to the main air inlet and the air outlet, the secondary flow channel is connected to the secondary air inlet and the air outlet, and the main flow channel is at least partially separated from the secondary flow channel; And wherein, the impeller assembly further includes a wind baffle plate, and the wind baffle plate is arranged between the main flow channel and the secondary flow channel to at least partially separate the main flow channel from the secondary flow channel.

2. The centrifugal fan according to claim 1, wherein the wind baffle has a disc shape and extends outward from the central axis to the main blade in the radial direction, the main flow channel is located on the front side of the wind baffle, and the secondary flow channel is located on the rear side of the wind baffle.

3. The centrifugal fan according to claim 2, wherein a groove is formed on the back plate and is recessed toward the front side, the groove having a groove bottom plate and a groove side plate, the groove bottom plate faces the back plate, the groove side plate extends from the groove bottom plate to the back plate, a plurality of through slots are formed on the groove side plate, and the through slots form the secondary flow channel. The centrifugal fan according to claim 3 , wherein the groove side plate extends in a direction perpendicular to the back plate. 5 . The centrifugal fan according to claim 4 , wherein the groove bottom plate is provided with auxiliary blades, and the auxiliary blades are configured to suck gas from the auxiliary air inlet. The centrifugal fan according to claim 4 , wherein the auxiliary blades extend from the groove bottom plate to the inner side of the back plate.

7. The centrifugal fan according to claim 4, wherein the auxiliary blades are flipped out from the groove bottom plate through the material at the through-slot opening.

8. The centrifugal fan according to claim 3, wherein the groove side plates extend from the groove bottom plate to the back plate in a radially outward direction. 9 . The centrifugal fan according to claim 8 , wherein the groove side plate is configured to draw gas from the secondary air inlet.

10. The centrifugal fan according to any one of claims 3 to 8, wherein the through slots penetrate through the inner side of the back plate on the groove side plate.

11. The centrifugal fan according to any one of claims 3 to 8, wherein the wind baffle plate is in contact with the groove bottom plate.

12. The centrifugal fan according to any one of claims 3 to 8, wherein the wind baffle plate, the groove bottom plate and the back plate are respectively provided with axial holes aligned with each other, and the axial holes are aligned with the output shaft.

13. The centrifugal fan according to claim 1, wherein the wind baffle is fixed to the output shaft by a nut. 14 . The centrifugal fan according to claim 1 , further comprising a sealing gasket disposed between the output shaft and the housing.

15. The centrifugal fan according to claim 1, further comprising a sealing groove, wherein the sealing groove is arranged on an outer peripheral surface of the housing facing the front cover, a sealing strip is placed in the sealing groove, and the sealing strip is used for sealing between the housing and the front cover.

Images