Centrifugal air compression equipment

Abstract

The utility model provides high-pressurization, compact-structure and low-axial-force centrifugal air compression equipment which is provided with a centrifugal aerostatic press main body device comprising a motor comprising a stator, a rotor and a main shaft fixed to the rotor, a first-stage centrifugal aerostatic press arranged on one side of the motor in the axial direction of the main shaft and comprising a first-stage double-faced impeller, and a second-stage centrifugal aerostatic press arranged on the other side of the main shaft and comprising a second-stage double-faced impeller. The first-stage double-sided impeller is fixedly arranged at the first end part of the main shaft; the second-stage centrifugal aerostatic press is arranged on the other side of the motor in the axial direction of the main shaft and comprises a second-stage impeller, and the second-stage impeller is fixedly arranged at the second end of the main shaft; the third-stage centrifugal aerostatic press is also arranged on the other side of the motor in the axial direction of the main shaft and comprises a third-stage impeller, the third-stage impeller is fixedly arranged at the second end of the main shaft, and the first-stage double-sided impeller, the rotor, the second-stage impeller and the third-stage impeller are sequentially and coaxially arranged in the axial direction of the main shaft; the second-stage impeller and the third-stage impeller are arranged in a back-to-back mode.

Description

Technical Field

[0001] This application relates to the technical field of compressor equipment, and particularly to a centrifugal air compression equipment. Background Art

[0002] At present, centrifugal air compression equipment has a wide range of application scenarios. However, the pressure of a single-stage compressor is insufficient, the pressure increase of a two-stage compressor is limited, and the internal structure of a multi-stage compressor is often complex, occupying a large space. The large axial force in a multi-stage compressor is not conducive to the rotation and operation of the bearings, affecting the performance and service life of the centrifugal air compression equipment.

[0003] Therefore, there is an urgent need for a new centrifugal air compression equipment. Summary of the Utility Model

[0004] An embodiment of this application provides a centrifugal air compression equipment, which has a centrifugal air compressor main device. The centrifugal air compressor main device includes:

[0005] A motor, including a stator, a rotor, and a main shaft fixed to the rotor:

[0006] A first-stage centrifugal air compressor, arranged on one side of the motor in the axial direction of the main shaft, including a first-stage double-sided impeller, and the first-stage double-sided impeller is fixedly arranged at the first end of the main shaft;

[0007] A second-stage centrifugal air compressor, arranged on the other side of the motor in the axial direction of the main shaft, including a second-stage impeller, and the second-stage impeller is fixedly arranged at the second end of the main shaft;

[0008] A third-stage centrifugal air compressor, also arranged on the other side of the motor in the axial direction of the main shaft, including a third-stage impeller, and the third-stage impeller is fixedly arranged at the second end of the main shaft,

[0009] Wherein, in the axial direction of the main shaft, the first-stage double-sided impeller, the rotor, the second-stage impeller, and the third-stage impeller are arranged in sequence and coaxially, and the second-stage impeller and the third-stage impeller are arranged in a back-to-back manner.

[0010] In the centrifugal air compression equipment provided by the present application, a first-stage centrifugal air compressor, a second-stage centrifugal air compressor, and a third-stage centrifugal air compressor are provided. The first-stage double-sided impeller, the second-stage impeller, and the third-stage impeller are coaxially arranged on the main shaft. The motor drives the motor rotor to rotate and simultaneously drives the first-stage double-sided impeller, the second-stage impeller, and the third-stage impeller to operate synchronously. The gas to be compressed entering the main device of the centrifugal air compressor can be compressed in three stages by the first-stage double-sided impeller, the second-stage impeller, and the third-stage impeller to achieve the purpose of high supercharging. The first-stage double-sided impeller, the second-stage impeller, and the third-stage impeller are connected in series through the main shaft on the motor rotor, making the overall integration of the equipment highly compact. Through three-stage coaxial arrangement, higher exhaust pressure can be generated at a relatively low speed of the motor. Under the condition of the same pressure, compared with single-stage or two-stage electric compressors, its speed is significantly reduced, further improving the reliability margin of the whole machine. The first-stage centrifugal air compressor is arranged on one side of the motor in the axial direction of the main shaft. When the motor is working, the first-stage double-sided impeller in the first-stage centrifugal air compressor sucks in gas on both the front and back sides simultaneously, and the axial forces on this side of the motor can be offset from each other. The second-stage centrifugal air compressor and the third-stage centrifugal air compressor are arranged on the other side of the motor in the axial direction of the main shaft, and the second-stage impeller and the third-stage impeller are arranged back-to-back, which can also effectively reduce the axial force. Thus, the reliability of the bearing structure is greatly improved. By arranging the first-stage centrifugal air compressor and the second and third-stage centrifugal air compressors on different sides of the motor and making the impellers of each stage of the centrifugal air compressor coaxial, the high compactness of the whole equipment is achieved.

[0011] In some alternative embodiments of the present application, the main device of the centrifugal air compressor further includes:

[0012] Bearings, including a first bearing and a second bearing. The first bearing is arranged on one side of the stator close to the first-stage double-sided impeller and is assembled in cooperation with the main shaft. The second bearing is arranged on one side of the stator close to the second-stage impeller and is assembled in cooperation with the main shaft.

[0013] In the axial direction of the main shaft, the bearings are located between the first-stage double-sided impeller and the second-stage impeller.

[0014] In some alternative embodiments of the present application, the motor further includes a spacer back plate. The spacer back plate is located inside the cylindrical housing of the motor. The spacer back plate is arranged on the side of the first bearing close to the first-stage double-sided impeller. The spacer back plate is used to fix the thrust foil provided on the side of the first bearing close to the first-stage double-sided impeller. The spacer back plate is formed with a central shaft hole. The main shaft passes through the central shaft hole, and a labyrinth seal is arranged between the main shaft and the central shaft hole at the position of the central shaft hole.

[0015] In some alternative embodiments of the present application, the first-stage centrifugal air compressor is arranged on one side of the motor. The first-stage double-sided impeller includes a first-stage front impeller and a first-stage back impeller arranged back to back.

[0016] The first-stage centrifugal air compressor further includes:

[0017] A first outer casing, including a first volute and a first air inlet device. The first volute and the first air inlet device are connected to each other and form a first diffuser space for accommodating the first-stage double-sided impeller. The first volute is arranged corresponding to the front impeller of the first stage, and the first air inlet device is arranged corresponding to the rear impeller of the first stage. The first air inlet device is connected to the first end of the columnar casing of the motor.

[0018] In some alternative embodiments of the present application, the first air inlet of the first volute is communicated with the front impeller of the first stage and is axially opposite to the front impeller of the first stage. The gas to be compressed entering from the first air inlet is compressed by the front impeller of the first stage.

[0019] The first air inlet device is provided with a second air inlet, and the second air inlet is communicated with the rear impeller of the first stage. The gas to be compressed entering from the first air inlet is compressed by the rear impeller of the first stage.

[0020] In some alternative embodiments of the present application, the first outer casing is further provided with a first air outlet, and the first air outlet is communicated with the first diffuser space. The gas compressed by the first-stage double-sided impeller flows out of the first outer casing from the first air outlet.

[0021] In some alternative embodiments of the present application, the second-stage centrifugal air compressor further includes a second-stage compressor volute, and the third-stage centrifugal air compressor further includes a third-stage compressor volute, wherein

[0022] The second-stage compressor volute is connected to the second end of the columnar casing. The first end and the second end are opposite to each other in the axial direction of the main shaft. The third-stage compressor volute is arranged on the side of the second-stage compressor volute facing away from the columnar casing and is connected to the second-stage compressor volute.

[0023] In some alternative embodiments of the present application, an inter-stage back plate is fixedly arranged between the second-stage compressor volute and the third-stage compressor volute. The second-stage compressor volute forms a first chamber for accommodating the second-stage impeller, and the third-stage compressor volute forms a second chamber for accommodating the third-stage impeller. The first chamber and the second chamber are separated by the second back plate.

[0024] In some alternative embodiments of the present application, the total air outlet of the centrifugal air compressor main device is arranged on the third-stage compressor volute and is communicated with the second chamber.

[0025] The gas to be compressed is successively compressed by the first-stage centrifugal air compressor, the second-stage centrifugal air compressor and the third-stage centrifugal air compressor in the centrifugal air compressor main device and then flows out from the total air outlet.

[0026] The size of the second-stage impeller is larger than the size of the third-stage impeller.

[0027] In some alternative embodiments of the present application, the centrifugal air compression device further includes a first-stage cooler and a second-stage cooler.

[0028] The outlet end of the first-stage centrifugal air compressor is connected to the inlet end of the first-stage cooler, the outlet end of the first-stage cooler is connected to the inlet end of the second-stage centrifugal air compressor, the outlet end of the second-stage centrifugal air compressor is connected to the inlet end of the second-stage cooler, and the outlet end of the second-stage cooler is connected to the inlet end of the third-stage centrifugal air compressor. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic cross-sectional structure diagram of the centrifugal air compressor main device in the centrifugal air compression device provided by the embodiment of the present application;

[0031] Figure 2 It is a schematic three-dimensional cross-sectional structure diagram of the centrifugal air compression device provided by the embodiment of the present application.

[0032] Description of the reference numerals:

[0033] 1 - First-stage double-sided impeller; 2 - First volute; 21 - First air inlet; 22 - First air outlet; 3 - First air intake device; 31 - Second air inlet; 4 - Rotor; 41 - Main shaft; 5 - Stator; 6 - Columnar housing; 61 - Spacer back plate; 62 - Labyrinth seal; 63 - Thrust foil; 7 - Bearing; 8 - Second-stage compressor volute; 81 - Inlet of the second-stage centrifugal air compressor; 9 - Second-stage impeller; 10 - Third-stage impeller; 11 - Third-stage compressor volute; 111 - Inlet of the third-stage centrifugal air compressor; 112 - Total air outlet; 12 - Inter-stage back plate; 13 - First-stage cooler; 14 - Second-stage cooler;

[0034] First diffuser space - A; Detailed Embodiments

[0035] The following will combine the attached Figure 1 to the attached Figure 2 to detail the technical solutions of the present application.

[0036] As Figure 1 shown, the embodiment of the present application provides a centrifugal air compression device having a centrifugal air compressor main device, and the centrifugal air compressor main device includes:

[0037] A motor, comprising a stator 5, a rotor 4 and a main shaft 41 fixed to the rotor 4:

[0038] A first-stage centrifugal air compressor, arranged on one side of the motor in the axial direction of the main shaft 41, comprising a first-stage double-sided impeller 1, and the first-stage double-sided impeller 1 is fixedly arranged at a first end of the main shaft 41;

[0039] A second-stage centrifugal air compressor, arranged on the other side of the motor in the axial direction of the main shaft 41, comprising a second-stage impeller 9, and the second-stage impeller 9 is fixedly arranged at a second end of the main shaft 41;

[0040] A third-stage centrifugal air compressor, also arranged on the other side of the motor in the axial direction of the main shaft 41, comprising a third-stage impeller 10, and the third-stage impeller 10 is fixedly arranged at the second end of the main shaft 41,

[0041] Wherein, in the axial direction of the main shaft 41, the first-stage double-sided impeller 1, the rotor 4, the second-stage impeller 9 and the third-stage impeller 10 are arranged in sequence and coaxially arranged, and the second-stage impeller 9 and the third-stage impeller 10 are arranged in a back-to-back manner.

[0042] In the centrifugal air compression equipment provided by the present application, a first-stage centrifugal air compressor, a second-stage centrifugal air compressor and a third-stage centrifugal air compressor are provided. The first-stage double-sided impeller 1, the second-stage impeller 9 and the third-stage impeller 10 are coaxially arranged on the main shaft 41. The motor drives the motor rotor 4 to rotate and simultaneously drives the first-stage double-sided impeller 1, the second-stage impeller 9 and the third-stage impeller 10 to operate synchronously. The gas to be compressed entering the main body device of the centrifugal air compressor can be compressed in three stages by the first-stage double-sided impeller 1, the second-stage impeller 9 and the third-stage impeller 10 to achieve the purpose of high supercharging. The first-stage double-sided impeller 1, the second-stage impeller 9 and the third-stage impeller 10 are connected in series through the main shaft 41 on the motor rotor 4, so that the overall integration of the equipment is highly compact. Through the three-stage coaxial arrangement, higher exhaust pressure can be generated at a lower rotational speed of the motor. Under the condition of the same pressure, compared with single-stage or two-stage electric compressors, its rotational speed is greatly reduced, further improving the reliability margin of the whole machine. The first-stage centrifugal air compressor is arranged on one side of the motor in the axial direction of the main shaft 41. When the motor is working, the first-stage double-sided impeller 1 in the first-stage centrifugal air compressor sucks in gas on both the front and back sides at the same time, and the axial force on this side of the motor can be offset from each other. The second-stage centrifugal air compressor and the third-stage centrifugal air compressor are arranged on the other side of the motor in the axial direction of the main shaft 41, and the second-stage impeller 9 and the third-stage impeller 10 are arranged in a back-to-back manner, which can also effectively reduce the axial force. Thus, the reliability of the bearing 7 structure is greatly improved. By arranging the first-stage centrifugal air compressor and the second- and third-stage centrifugal air compressors on different sides of the motor and the impellers of each stage of the centrifugal air compressor being coaxial, the high compactness of the whole equipment is realized.

[0043] In some alternative embodiments of the present application, the centrifugal compressor main body device further includes:

[0044] Bearings 7, including a first bearing 7 and a second bearing 7. The first bearing 7 is arranged on one side of the stator 5 close to the first-stage double-sided impeller 1 and is fitted with the main shaft 41, and the second bearing 7 is arranged on one side of the stator 5 close to the second-stage impeller 9 and is fitted with the main shaft 41.

[0045] Axially on the main shaft 41, the bearings 7 are located between the first-stage double-sided impeller 1 and the second-stage impeller 9.

[0046] In some alternative embodiments of the present application, the motor further includes a spacer back plate 61. The spacer back plate 61 is located inside the cylindrical housing 6 of the motor. The spacer back plate 61 is arranged on the side of the first bearing close to the first-stage double-sided impeller 1. The spacer back plate 61 is used to fix the thrust foil 63 arranged on the side of the first bearing close to the first-stage double-sided impeller. The spacer back plate 61 is formed with a central shaft hole. The main shaft 41 passes through the central shaft hole, and a labyrinth seal 62 is arranged between the main shaft and the central shaft hole.

[0047] In these embodiments, the labyrinth seal 62 is arranged for gas sealing to prevent the cooling gas in the motor from leaking to the end of the centrifugal compressor main body device where the first-stage centrifugal compressor is arranged, affecting the cooling effect and aerodynamic performance.

[0048] The spacer back plate 61 is located inside the cylindrical housing 6 of the motor, and the spacer back plate 61 is arranged on the side of the first bearing 7 close to the first-stage double-sided impeller 1.

[0049] In some alternative embodiments of the present application, the first-stage centrifugal compressor is arranged on one side of the motor. The first-stage double-sided impeller 1 includes a first-stage front impeller and a first-stage back impeller arranged back to back.

[0050] The first-stage centrifugal compressor further includes:

[0051] A first housing body, including a first volute 2 and a first air inlet device 3. The first volute 2 and the first air inlet device 3 are connected to each other and form a first diffuser space A for accommodating the first-stage double-sided impeller 1. The first volute 2 corresponds to the first-stage front impeller, and the first air inlet device 3 corresponds to the first-stage back impeller. The first air inlet device 3 is connected to the first end of the cylindrical housing 6 of the motor.

[0052] In some alternative embodiments of the present application, the first air inlet 21 of the first volute 2 is communicated with the first-stage front impeller and is axially aligned with the first-stage front impeller. The gas to be compressed entering from the first air inlet 21 is compressed by the first-stage front impeller.

[0053] The first intake device 3 is provided with a second intake port 31, and the second intake port 31 communicates with the back impeller of the first stage. The gas to be compressed entering from the first intake port 21 is compressed by the back impeller of the first stage.

[0054] In some alternative embodiments of the present application, the first outer casing is further provided with a first outlet port 22, and the first outlet port 22 communicates with the first diffuser space A. The gas compressed by the first stage double-sided impeller 1 flows out of the first outer casing from the first outlet port 22.

[0055] In some alternative embodiments of the present application, the second-stage centrifugal gas compressor further includes a second-stage compressor volute 8, and the third-stage centrifugal gas compressor further includes a third-stage compressor volute 11, wherein,

[0056] The second-stage compressor volute 8 is connected to the second end of the cylindrical outer casing 6. The first end and the second end are opposite to each other in the axial direction of the main shaft 41. The third-stage compressor volute 11 is disposed on the side of the second-stage compressor volute 8 facing away from the cylindrical outer casing 6 and is connected to the second-stage compressor volute 8.

[0057] In some alternative embodiments of the present application, an inter-stage back plate 12 is fixedly provided between the second-stage compressor volute 8 and the third-stage compressor volute 11. The second-stage compressor volute 8 forms a first chamber for accommodating the second-stage impeller 9, and the third-stage compressor volute 11 forms a second chamber for accommodating the third-stage impeller 10. The first chamber and the second chamber are separated by the second back plate.

[0058] In some alternative embodiments of the present application, the total outlet port 112 of the centrifugal gas compressor main device is provided on the third-stage compressor volute 11 and communicates with the second chamber.

[0059] The gas to be compressed is sequentially compressed by the first-stage centrifugal gas compressor, the second-stage centrifugal gas compressor, and the third-stage centrifugal gas compressor in the centrifugal gas compressor main device and then flows out from the total outlet port 112.

[0060] The size of the second-stage impeller 9 is larger than the size of the third-stage impeller 10.

[0061] In these embodiments, since the gas to be compressed sequentially passes through the first-stage double-sided impeller 1, the second-stage impeller 9, and the third-stage impeller 10 for three-stage compression. Under the condition of continuous gas flow, after the gas is compressed step by step through three stages, the reduced intake volume in the standard state entering the next-stage compressor will decrease. Therefore, under a reasonable compression ratio distribution, the impeller size should show a gradually decreasing state. Therefore, the size of the second-stage impeller 9 is set larger than the size of the third-stage impeller 10. The compression ratio is the ratio of the absolute pressure at intake to the absolute pressure at exhaust when the compressor compresses the working medium.

[0062] As Figure 2 shown,Figure 2 The double arrow in the middle points to the direction of gas flow when the gas is compressed. In some alternative embodiments of the present application, the centrifugal air compression device further includes a first-stage cooler 13 and a second-stage cooler 14.

[0063] The outlet end of the first-stage centrifugal air compressor is connected to the inlet end of the first-stage cooler 13, the outlet end of the first-stage cooler 13 is connected to the inlet end of the second-stage centrifugal air compressor, the outlet end of the second-stage centrifugal air compressor is connected to the inlet end of the second-stage cooler 14, and the outlet end of the second-stage cooler 14 is connected to the inlet end of the third-stage centrifugal air compressor.

[0064] In some specific examples of these embodiments, the gas to be compressed first enters the first-stage centrifugal air compressor through the first air inlet 21 of the first volute 2 and the second air inlet 31 of the first air inlet device 3. After being compressed by the first-stage double-sided impeller 1, it flows out of the first housing through the first air outlet 22 of the first housing. The first compressed gas that flows out enters the first-stage cooler 13 through an external connecting pipe. The first air outlet 22 of the first housing is communicated with the inlet of the first-stage cooler 13 through an external connecting pipe to realize the connection between the outlet end of the first-stage centrifugal air compressor and the inlet end of the first-stage cooler 13.

[0065] The first-stage compressed gas flows out of the first-stage cooler 13 after being cooled by the first-stage cooler 13 and enters the second-stage centrifugal air compressor through an external connecting pipe. Among them, the air inlet 81 of the second-stage centrifugal air compressor is communicated with the outlet of the first-stage cooler 13 through an external connecting pipe to realize the connection between the outlet end of the first-stage cooler 13 and the inlet end of the second-stage centrifugal air compressor. The air inlet 81 of the second-stage centrifugal air compressor is formed on the second-stage compressor volute 8.

[0066] The cooled first-stage compressed gas is compressed by the second-stage centrifugal air compressor and then the second-stage compressed gas flows out from the outlet of the second-stage centrifugal air compressor. The second-stage compressed gas that flows out enters the second-stage cooler 14 through an external connecting pipe. The outlet of the second-stage centrifugal air compressor is communicated with the inlet of the second-stage cooler 14 through an external connecting pipe to realize the connection between the outlet end of the second-stage centrifugal air compressor and the inlet end of the second-stage cooler 14. The outlet of the second-stage centrifugal air compressor is also formed on the second-stage compressor volute 8, Figure 2 not shown in the figure.

[0067] The cooled second-stage compressed gas flows out of the second-stage cooler 14 after being cooled by the second-stage cooler 14 and enters the third-stage centrifugal air compressor through an external connecting pipe. Among them, the air inlet 111 of the third-stage centrifugal air compressor is communicated with the outlet of the second-stage cooler 14 through an external connecting pipe to realize the connection between the outlet end of the second-stage cooler 14 and the inlet end of the third-stage centrifugal air compressor.

[0068] The secondary compressed gas flows out from the total gas outlet 112 provided on the third-stage centrifugal gas compressor after being compressed by the third-stage centrifugal gas compressor, and thus the three-stage compression of the gas to be compressed is completed.

[0069] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claimed rights.

Claims

1. A centrifugal air compression device, characterized in that: The invention has a centrifugal air compressor main body device, and the centrifugal air compressor main body device comprises: The motor includes a stator, a rotor and a main shaft fixed to the rotor: A first-stage centrifugal air compressor is arranged on one side of the motor in the axial direction of the main shaft, and includes a first-stage double-sided impeller, and the first-stage double-sided impeller is fixedly arranged on the first end of the main shaft; A second-stage centrifugal air compressor is arranged on the other side of the motor in the axial direction of the main shaft, and includes a second-stage impeller, and the second-stage impeller is fixedly arranged on the second end of the main shaft; A third-stage centrifugal air compressor is also arranged on the other side of the motor in the axial direction of the main shaft, and includes a third-stage impeller, and the third-stage impeller is fixedly arranged on the second end of the main shaft; A bearing, comprising a first bearing and a second bearing, wherein the first bearing is arranged on a side of the stator close to the first-stage double-sided impeller and is assembled with the main shaft, and the second bearing is arranged on a side of the stator close to the second-stage impeller and is assembled with the main shaft, and in the axial direction of the main shaft, the bearing is located between the first-stage double-sided impeller and the second-stage impeller; Wherein, in the axial direction of the main shaft, the first-stage double-sided impeller, the rotor, the second-stage impeller and the third-stage impeller are arranged in sequence and coaxially, and the second-stage impeller and the third-stage impeller are arranged back to back. The motor also includes a spacer backplate, which is located in the cylindrical housing of the motor. The spacer backplate is arranged on the side of the first bearing close to the first-stage double-sided impeller. The spacer backplate is used to fix the thrust foil arranged on the side of the first bearing close to the first-stage double-sided impeller. The spacer backplate is formed with a central shaft hole, the main shaft passes through the central shaft hole, and a labyrinth seal is arranged between the main shaft and the central shaft hole.

2. The centrifugal air compression device according to claim 1, characterized in that: The first-stage centrifugal compressor is arranged on one side of the motor, and the first-stage double-sided impeller includes a first-stage front impeller and a first-stage back impeller arranged opposite to each other. The first-stage centrifugal air compressor also includes: The first outer shell includes a first volute and a first air intake device, the first volute and the first air intake device are interconnected and form a first diffusion space for accommodating the first-stage double-sided impeller, the first volute is arranged corresponding to the first-stage front impeller, the first air intake device is arranged corresponding to the first-stage back impeller, and the first air intake device is connected to the first end of the columnar outer shell of the motor.

3. The centrifugal air compression device according to claim 2, characterized in that: The first air inlet of the first volute is connected to the first-stage front impeller and is arranged opposite to the first-stage front impeller in the axial direction. The gas to be compressed entering from the first air inlet is compressed by the first-stage front impeller. The first air intake device is provided with a second air intake port, and the second air intake port is connected to the first-stage back impeller. The gas to be compressed entering from the first air intake port is compressed by the first-stage back impeller.

4. The centrifugal air compression device according to claim 3, characterized in that: The first outer shell is also provided with a first air outlet, which is communicated with the first pressure diffusion space, and the gas compressed by the first-stage double-sided impeller flows out of the first outer shell through the first air outlet.

5. The centrifugal air compression device according to claim 2, characterized in that: The second-stage centrifugal compressor further includes a second-stage compressor volute, and the third-stage centrifugal compressor further includes a third-stage compressor volute, wherein: The second-stage compressor volute is connected to the second end of the cylindrical outer casing, the first end and the second end are opposite to each other in the axial direction of the main shaft, and the third-stage compressor volute is arranged on the side of the second-stage compressor volute facing away from the cylindrical outer casing and is connected to the second-stage compressor volute.

6. The centrifugal air compression device according to claim 5, characterized in that: An interstage back plate is fixedly arranged between the second-stage compressor volute and the third-stage compressor volute, the second-stage compressor volute forms a first chamber for accommodating the second-stage impeller, the third-stage compressor volute forms a second chamber for accommodating the third-stage impeller, and the first chamber and the second chamber are separated by the interstage back plate.

7. The centrifugal air compression device according to claim 6, characterized in that: The main air outlet of the centrifugal air compressor main device is arranged on the third-stage compressor volute and communicates with the second chamber. The gas to be compressed is compressed in the centrifugal compressor main device in sequence by the first-stage centrifugal compressor, the second-stage centrifugal compressor and the third-stage centrifugal compressor, and then flows out from the main gas outlet; The size of the second-stage impeller is larger than that of the third-stage impeller.

8. The centrifugal air compression device according to claim 7, characterized in that: The centrifugal air compression device also includes a first-stage cooler and a second-stage cooler. The air outlet of the first-stage centrifugal air compressor is connected to the air inlet of the first-stage cooler, the air outlet of the first-stage cooler is connected to the air inlet of the second-stage centrifugal air compressor, the air outlet of the second-stage centrifugal air compressor is connected to the air inlet of the second-stage cooler, and the air outlet of the second-stage cooler is connected to the air inlet of the third-stage centrifugal air compressor.

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