Gas compression assembly for centrifugal compressor and centrifugal compressor

Abstract

The invention discloses a gas compression assembly for a centrifugal compressor and the centrifugal compressor, and relates to the technical field of compressors, the gas compression assembly comprises a motor, a first-stage pressing wheel, a second-stage pressing wheel and a third-stage pressing wheel, the motor is provided with a rotor shaft, the first-stage pressing wheel is fixedly arranged at the first end of the rotor shaft, and the second-stage pressing wheel is fixedly arranged at the second end of the rotor shaft; the first-stage pressing wheel nose is located on the side, away from the motor, of the first-stage pressing wheel back, the second-stage pressing wheel is fixedly arranged at the second end of the rotor shaft, the second-stage pressing wheel back is located on the side, away from the motor, of the second-stage pressing wheel nose, and the third-stage pressing wheel is fixedly arranged at the second end of the rotor shaft and located on the side, away from the motor, of the second-stage pressing wheel. The third-stage pressing wheel nose is located on the side, away from the motor, of the third-stage pressing wheel back. According to the gas compression assembly, self-balance of the axial force of the gas compression assembly can be achieved, the stability of the gas compression assembly during working can be improved, the reliability of the centrifugal compressor can be improved, gas leakage can be reduced, and the working efficiency of the gas compression assembly can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a gas compression component for a centrifugal compressor and a centrifugal compressor having the gas compression component. Background Art

[0002] In the related art, the gas compression assembly of the existing centrifugal compressor cannot achieve self-balance of the axial force, and is subjected to high axial force, which affects the reliability of the compressor, and the gas compression assembly is prone to gas leakage. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide a gas compression assembly for a centrifugal compressor, which can achieve self-balance of the axial force of the gas compression assembly, reduce the axial force, and help improve the stability of the gas compression assembly during operation, help improve the reliability of the centrifugal compressor, and can also reduce gas leakage and improve the working efficiency of the gas compression assembly.

[0004] The present invention further provides a centrifugal compressor using the gas compression assembly.

[0005] According to a first aspect of the present invention, a gas compression assembly for a centrifugal compressor includes: a motor, a primary pressure wheel, a secondary pressure wheel and a tertiary pressure wheel, wherein the motor has a rotor shaft, the primary pressure wheel is fixedly arranged at the first end of the rotor shaft, the primary pressure wheel has a primary pressure wheel nose and a primary pressure wheel back, the primary pressure wheel nose is located on the side of the primary pressure wheel back away from the motor, the secondary pressure wheel is fixedly arranged at the second end of the rotor shaft, the secondary pressure wheel has a secondary pressure wheel nose and a secondary pressure wheel back, the secondary pressure wheel back is located on the side of the secondary pressure wheel nose away from the motor, the secondary pressure wheel is used to compress the gas compressed by the primary pressure wheel, the tertiary pressure wheel is fixedly arranged at the second end of the rotor shaft and located on the side of the secondary pressure wheel away from the motor, the tertiary pressure wheel has a tertiary pressure wheel nose and a tertiary pressure wheel back, the tertiary pressure wheel nose is located on the side of the tertiary pressure wheel back away from the motor, and the tertiary pressure wheel is used to compress the gas compressed by the secondary pressure wheel.

[0006] According to the gas compression assembly of the embodiment of the present application, the rotor shaft can be subjected to a smaller stable axial force, so that the rotor shaft can rotate stably, and the self-balance of the axial force of the gas compression assembly can be achieved. The axial force is reduced, which is beneficial to improving the stability of the gas compression assembly during operation and the reliability of the centrifugal compressor. It can also reduce gas leakage and improve the working efficiency of the gas compression assembly.

[0007] According to some embodiments of the present invention, the outer diameter dimension of the first-stage pressure wheel back is D1, the outer diameter dimension of the second-stage pressure wheel back is D2, and the outer diameter dimension of the third-stage pressure wheel back is D3, satisfying the relationship: D1:D2:D3 is 1:0.77:0.84.

[0008] According to some embodiments of the present invention, the outer diameter dimension of the first-stage pressure roller nose is D4, satisfying the relationship: 130mm≤D1≤134mm, 82mm≤D4≤86mm; the outer diameter dimension of the second-stage pressure roller nose is D5, satisfying the relationship: 99mm≤D2≤102mm, 78mm≤D5≤82mm; the outer diameter dimension of the tertiary pressure roller nose is D6, satisfying the relationship: 108mm≤D3≤112mm, 58mm≤D6≤62mm.

[0009] According to some embodiments of the present invention, the first-stage impeller and the second-stage impeller are closed impellers, and the third-stage impeller is an open impeller.

[0010] According to some embodiments of the present invention, the gas pressure inside the motor is higher than the gas pressure at the back of the first-stage pressure wheel, and the gas pressure inside the motor is higher than the gas pressure at the nose of the second-stage pressure wheel.

[0011] According to some embodiments of the present invention, the motor further has an outer shell and a stator, the outer shell defines an installation cavity, the stator is disposed in the installation cavity and fixed to the shell side wall of the outer shell, the rotor shaft is rotatably disposed in the outer shell and penetrates the outer shell, the shell side wall is formed with a wire outlet hole connected to the installation cavity, the wire outlet hole is located at the end position of the shell side wall away from the primary pressure wheel, and the electrical connection wire of the stator is installed in the wire outlet hole.

[0012] According to some embodiments of the present invention, the motor further has an outer shell, the outer shell has a mounting seat opposite to the secondary pressure wheel, the rotor shaft passes through the mounting seat and is rotatable relative to the mounting seat, and a guide structure is formed on the surface of the mounting seat facing the secondary pressure wheel, and the guide structure is configured to guide the gas compressed by the primary pressure wheel to the secondary pressure wheel.

[0013] According to some embodiments of the present invention, the motor further comprises an outer shell, a cooling channel is formed in a shell side wall of the outer shell, and a heat dissipation structure is formed on an inner surface of the cooling channel.

[0014] According to some embodiments of the present invention, the gas compression assembly for a centrifugal compressor further includes: a partition plate, which is sleeved on the rotor shaft and located between the secondary pressure wheel and the tertiary pressure wheel to separate the secondary pressure wheel from the tertiary pressure wheel.

[0015] A centrifugal compressor according to an embodiment of the second aspect of the present invention comprises the gas compression assembly described in the above embodiment.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1 is a cross-sectional view of a gas compression assembly according to an embodiment of the present application;

[0019] Figure 2 yes Figure 1 A partial enlarged schematic diagram of the middle A area;

[0020] Figure 3 yes Figure 1 A partial enlarged schematic diagram of area B in the middle.

[0021] Reference numerals:

[0022] Gas compression component 1,

[0023] Motor 10, rotor shaft 11, weight reduction space 111, outer shell 12, mounting cavity 121, shell side wall 122, outlet hole 1221, cooling channel 1222, inner wall 1223, outer wall 1224, mounting seat 123, flow guide structure 1231, mounting through hole 1232, sealing groove 1233, second abutting surface 1234, stator 13, electrical connection line 131, first air radial bearing 14, second air radial bearing 15,

[0024] The first-stage pressing wheel 20, the first-stage pressing wheel nose 21, the first-stage pressing wheel back 22, the first assembly hole 23, the first mounting hole 24,

[0025] Secondary pressing wheel 30, secondary pressing wheel nose 31, secondary pressing wheel back 32, first mounting groove 321, second assembly hole 33,

[0026] The third-stage pressing wheel 40, the third-stage pressing wheel nose 41, the third-stage pressing wheel back 42, the second mounting groove 421, the third assembly hole 43, the second mounting hole 44,

[0027] Shaft seal 50, sealing boss 51, first abutting surface 52,

[0028] Gas flow channel 60,

[0029] Air thrust bearing 70, thrust plate 71,

[0030] Back plate 80, third through hole 81,

[0031] End wall 90 , second through hole 91 . DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0033] Reference below Figure 1-Figure 3 A gas compression assembly 1 for a centrifugal compressor according to an embodiment of the present invention is described. The gas compression assembly 1 can be installed on a centrifugal compressor.

[0034] According to the first aspect of the present invention, a gas compression assembly 1 for a centrifugal compressor is provided. Figure 1 and Figure 2 As shown, the gas compression assembly 1 may include: a motor 10, a first-stage pressure wheel 20, a second-stage pressure wheel 30 and a third-stage pressure wheel 40, the motor 10 has a rotor shaft 11, the first-stage pressure wheel 20 is fixedly arranged at the first end of the rotor shaft 11, the first-stage pressure wheel 20 has a first-stage pressure wheel nose 21 and a first-stage pressure wheel back 22, the first-stage pressure wheel nose 21 is located on the side of the first-stage pressure wheel back 22 away from the motor 10, the second-stage pressure wheel 30 is fixedly arranged at the second end of the rotor shaft 11, the second-stage pressure wheel 30 has a second-stage pressure wheel nose 31 and a second-stage pressure wheel back 32, the secondary pressure roller back 32 is located on the side of the secondary pressure roller nose 31 away from the motor 10, the secondary pressure roller 30 is used to compress the gas compressed by the primary pressure roller 20, the tertiary pressure roller 40 is fixedly arranged at the second end of the rotor shaft 11 and is located on the side of the secondary pressure roller 30 away from the motor 10, the tertiary pressure roller 40 has a tertiary pressure roller nose 41 and a tertiary pressure roller back 42, the tertiary pressure roller nose 41 is located on the side of the tertiary pressure roller back 42 away from the motor 10, and the tertiary pressure roller 40 is used to compress the gas compressed by the secondary pressure roller 30.

[0035] It should be noted that in the related art, the gas compression assembly of the existing centrifugal compressor cannot achieve self-balance of the axial force, and is subjected to high axial force, which affects the reliability of the compressor, and the gas compression assembly is prone to gas leakage.

[0036] Based on this, the embodiment of the present application proposes a gas compression assembly 1 for a centrifugal compressor, wherein the motor 10 has a rotor shaft 11, and the rotor shaft 11 can extend along a first direction. Figure 1 When setting the direction, the first direction can be Figure 1In the X direction, the first direction may be parallel to the axial direction of the rotor shaft 11. The rotor shaft 11 may be made of magnetic steel material, and the rotor shaft 11 may be formed with a weight reduction space 111. By setting the rotor shaft 11 as a hollow shaft, the weight of the rotor shaft 11 may be reduced, which is beneficial to reducing costs, and the modal frequency of the rotor shaft 11 may be increased, reducing the risk of vibration when the rotor shaft 11 rotates, which is beneficial to reducing the weight of the gas compression assembly 1.

[0037] The rotor shaft 11 can be connected to the primary pressure wheel 20, the secondary pressure wheel 30, and the tertiary pressure wheel 40, and the rotor shaft 11 can drive the primary pressure wheel 20, the secondary pressure wheel 30, and the tertiary pressure wheel 40 to rotate together. When the primary pressure wheel 20 rotates, the primary pressure wheel 20 can compress the gas located in the primary pressure wheel 20, when the secondary pressure wheel 30 rotates, the secondary pressure wheel 30 can compress the gas located in the secondary pressure wheel 30, and when the tertiary pressure wheel 40 rotates, the tertiary pressure wheel 40 can compress the gas located in the tertiary pressure wheel 40. The primary pressure wheel 20 can be fixedly arranged at the first end of the rotor shaft 11, and the primary pressure wheel 20 can be fixedly connected to the rotor shaft 11 by means of clamping, bolting, etc. The first-stage pressure roller 20 has a first-stage pressure roller nose 21 and a first-stage pressure roller back 22. When the first-stage pressure roller 20 is assembled with the rotor shaft 11, the first-stage pressure roller nose 21 and the first-stage pressure roller back 22 can be arranged relatively to each other and spaced apart along a first direction. The first-stage pressure roller back 22 is located on the side of the first-stage pressure roller 20 facing the motor 10, and the first-stage pressure roller nose 21 is located on the side of the first-stage pressure roller back 22 away from the motor 10.

[0038] As an example, the first-stage pressure wheel 20 can be fixedly connected to the rotor shaft 11 by bolts, and the first-stage pressure wheel 20 can be formed with a first assembly hole 23, and the first assembly hole 23 is located on the side of the first-stage pressure wheel 20 facing the motor 10, and the rotor shaft 11 can extend into the first assembly hole 23, and the rotor shaft 11 can abut against the inner wall of the first assembly hole 23, so that the first-stage pressure wheel 20 can be sleeved on the rotor shaft 11. The first-stage pressure wheel 20 can be formed with a first mounting hole 24, and the first mounting hole 24 can penetrate the first-stage pressure wheel 20 along the first direction. The first mounting hole 24 and the first assembly hole 23 are arranged oppositely and communicated along the first direction. When the first-stage pressure wheel 20 is sleeved on the rotor shaft 11, the fixing bolts can be passed through the first mounting hole 24 and the first assembly hole 23 and assembled with the rotor shaft 11, so that the first-stage pressure wheel 20 and the rotor shaft 11 are fixedly connected, and the rotor shaft 11 can drive the first-stage pressure wheel 20 to rotate together.

[0039] The secondary roller 30 can be fixedly arranged at the second end of the rotor shaft 11, and the secondary roller 30 can be fixedly connected to the rotor shaft 11 by means of clamping, bolt connection, etc. The secondary roller 30 has a secondary roller nose 31 and a secondary roller wheel back 32. When the secondary roller 30 is assembled with the rotor shaft 11, the secondary roller nose 31 and the secondary roller wheel back 32 can be arranged opposite to each other and spaced apart along the first direction, the secondary roller nose 31 is located on the side of the secondary roller 30 facing the motor 10, and the secondary roller wheel back 32 is located on the side of the secondary roller nose 31 away from the motor 10. The gas compressed by the primary roller 20 can flow to the secondary roller 30, and the secondary roller 30 can be used to compress the gas compressed by the primary roller 20, and the pressure value of the gas compressed by the secondary roller 30 is higher than the pressure value of the gas compressed by the primary roller 20.

[0040] The tertiary roller 40 can be fixedly arranged at the second end of the rotor shaft 11, and the tertiary roller 40 can be fixedly connected to the rotor shaft 11 by means of clamping, bolt connection, etc., and the tertiary roller 40 can be located on the side of the secondary roller 30 away from the motor 10. The tertiary roller 40 has a tertiary roller nose 41 and a tertiary roller wheel back 42. When the tertiary roller 40 is assembled with the rotor shaft 11, the tertiary roller nose 41 and the tertiary roller wheel back 42 can be arranged oppositely and spaced apart along the first direction, the tertiary roller wheel back 42 is located on the side of the tertiary roller 40 facing the motor 10, and the tertiary roller nose 41 is located on the side of the tertiary roller wheel back 42 away from the motor 10. The gas compressed by the secondary roller 30 can flow to the tertiary roller 40, and the tertiary roller 40 can be used to compress the gas compressed by the secondary roller 30, and the pressure value of the gas compressed by the tertiary roller 40 is higher than the pressure value of the gas compressed by the secondary roller 30.

[0041] As an example, Figure 2As shown, the secondary pressure wheel 30 can be sleeved on the rotor shaft 11, the tertiary pressure wheel 40 can be fixedly connected to the rotor shaft 11 by bolts, and the secondary pressure wheel 30 can be sandwiched between the tertiary pressure wheel 40 and the motor 10. The secondary pressure wheel 30 can be formed with a second assembly hole 33, the second assembly hole 33 can penetrate the secondary pressure wheel 30 along the first direction, the rotor shaft 11 can be inserted into the second assembly hole 33, the rotor shaft 11 can abut against the inner wall of the second assembly hole 33, so that the secondary pressure wheel 30 can be sleeved on the rotor shaft 11. The tertiary pressure wheel 40 can be formed with a third assembly hole 43, the third assembly hole 43 can be located on the side of the tertiary pressure wheel 40 facing the motor 10, the rotor shaft 11 can extend into the third assembly hole 43, the rotor shaft 11 can abut against the inner wall of the third assembly hole 43, so that the tertiary pressure wheel 40 can be sleeved on the rotor shaft 11. The tertiary pressure wheel 40 may be formed with a second mounting hole 44, and the second mounting hole 44 may penetrate the tertiary pressure wheel 40 along the first direction. The second mounting hole 44 and the third assembly hole 43 may be arranged opposite to each other and communicated along the first direction. When the tertiary pressure wheel 40 is sleeved on the rotor shaft 11, the fixing bolt may be passed through the second mounting hole 44 and assembled with the rotor shaft 11. The tertiary pressure wheel 40 and the rotor shaft 11 are fixedly connected, and the secondary pressure wheel 30 is clamped between the tertiary pressure wheel 40 and the motor 10, so as to achieve the effect that the rotor shaft 11 drives the secondary pressure wheel 30 and the tertiary pressure wheel 40 to rotate together.

[0042] When the gas enters the gas compression assembly 1, the gas can be compressed in the first-stage compression wheel 20 first, and the gas compressed by the first-stage compression wheel 20 flows to the second-stage compression wheel 30, and the second-stage compression wheel 30 compresses the gas compressed by the first-stage compression wheel 20, so that the pressure of the gas increases, and the gas compressed by the second-stage compression wheel 30 flows to the third-stage compression wheel 40, and the third-stage compression wheel 40 compresses the gas compressed by the second-stage compression wheel 30, and the pressure ratio of the gas is further increased. The gas compression assembly 1 can achieve graded compression of the gas, so that the centrifugal compressor can achieve a higher pressure ratio. And the rotor shaft 11 is formed with a weight reduction space 111, which is conducive to reducing the weight of the gas compression assembly 1.

[0043] The first-stage pressure wheel back 22 is arranged toward the motor 10, the second-stage pressure wheel nose 31 is arranged toward the motor 10, the second-stage pressure wheel back 32 and the third-stage pressure wheel back 42 are arranged adjacent to each other, and the first-stage pressure wheel 20, the second-stage pressure wheel 30 and the third-stage pressure wheel 40 are connected in series, so that multi-stage compression of gas can be achieved. The gas compressed by the first-stage pressure wheel 10 can be further compressed by the second-stage pressure wheel 30, and the gas flowing out of the first-stage pressure wheel back 22 can flow into the second-stage pressure wheel nose 31. The gas pressure at the first-stage pressure roller back 22 is lower than the gas pressure at the third-stage pressure roller back 42, and the gas pressure at the second-stage pressure roller nose 31 is lower than the gas pressure at the third-stage pressure roller back 42. The first-stage pressure roller back 22 and the second-stage pressure roller nose 31 are respectively located on both sides of the motor 10 along the first direction, so that the pressure on both sides of the motor 10 is smaller, which can reduce the pressure difference between the motor 10 and the first-stage pressure roller 20, and the pressure difference between the motor 10 and the second-stage pressure roller 30. The probability of gas leakage between the motor 10 and the first-stage pressure roller 20 and the second-stage pressure roller 30 can be reduced, which can reduce gas leakage and improve the working efficiency of the gas compression assembly 1.

[0044] In the embodiment of the present application, the first-stage pressure wheel 20 can be one of an open impeller and a closed impeller, the second-stage pressure wheel 30 can be one of an open impeller and a closed impeller, and the third-stage pressure wheel 40 can be one of an open impeller and a closed impeller. When designing the structure of the gas compression assembly 1, different types of impellers can be selected according to the orientations of the first-stage pressure wheel 20, the second-stage pressure wheel 30, and the third-stage pressure wheel 40. As an example, the first-stage pressure wheel 20 and the second-stage pressure wheel 30 can be closed impellers, and the third-stage pressure wheel 40 can be an open impeller. The first-stage pressure wheel back 22 is arranged toward the motor 10, the second-stage pressure wheel nose 31 is arranged toward the motor 10, and the second-stage pressure wheel back 32 and the third-stage pressure wheel back 42 are arranged adjacent to each other, so that the rotor shaft 11 can be subjected to a smaller stable axial force, so that the rotor shaft 11 can rotate stably, and the axial force of the gas compression assembly 1 can be self-balanced, reducing the axial force, which is beneficial to improving the stability of the gas compression assembly 1 during operation and the reliability of the centrifugal compressor.

[0045] As an example, the outer surface of the head of the fixing bolt is constructed as an arc surface, and the arc surface can be a semicircular structure. When the compressed gas flows through the fixing bolt, the probability of the fixing bolt obstructing the gas flow can be reduced, which is beneficial to improving the working efficiency of the gas compression component 1.

[0046] In some embodiments of the present invention, the outer diameter of the first-stage pressure wheel back 22 is D1, the outer diameter of the second-stage pressure wheel back 32 is D2, and the outer diameter of the third-stage pressure wheel back 42 is D3, satisfying the relationship: D1:D2:D3 is 1:0.77:0.84.

[0047] For example, the outer diameter of the first-stage roller back 22 may be D1, the outer diameter of the second-stage roller back 32 may be 0.77D1, and the outer diameter of the third-stage roller back 42 may be 0.84D1. The outer diameter of the first-stage roller back 22, the outer diameter of the second-stage roller back 32, and the outer diameter of the third-stage roller back 42 are set in proportion. The outer diameter of the second-stage roller back 32 is 0.77 times the outer diameter of the first-stage roller back 22, and the outer diameter of the third-stage roller back 42 is 0.84 times the outer diameter of the first-stage roller back 22. If D1:D2:D3 does not satisfy 1:0.77:0.84, it will affect the total axial force on the gas compression assembly 1, affect the stable rotation of the rotor shaft 11, and cause the centrifugal compressor to be unable to achieve self-balance of the axial force, affect the stability of the gas compression assembly 1 during operation, and affect the reliability of the centrifugal compressor.

[0048] In some embodiments of the present invention, the outer diameter dimension of the first-stage pressure roller nose 21 is D4, satisfying the relationship: 130mm≤D1≤134mm, 82mm≤D4≤86mm; the outer diameter dimension of the second-stage pressure roller nose 31 is D5, satisfying the relationship: 99mm≤D2≤102mm, 78mm≤D5≤82mm; the outer diameter dimension of the third-stage pressure roller nose 41 is D6, satisfying the relationship: 108mm≤D3≤112mm, 58mm≤D6≤62mm.

[0049] Exemplarily, the outer diameter of the first-stage roller back 22 can be 130mm, 132mm, 133.2mm, 134mm, etc. The outer diameter of the first-stage roller back 22 can be in the range of 130mm to 134mm. Any value including the endpoint value is the outer diameter of the first-stage roller back 22 that can be selected in the present invention. If the outer diameter of the first-stage roller back 22 is less than 130mm, the axial force on the first-stage roller back 22 will be reduced. If the outer diameter of the first-stage roller back 22 is greater than 134mm, the axial force on the first-stage roller back 22 will be increased. If the axial force on the first-stage roller back 22 in the gas compression assembly 1 changes alone, it will affect the self-balance of the axial force of the gas compression assembly 1 and the reliability of the centrifugal compressor.

[0050] Exemplarily, the outer diameter of the first-stage roller nose 21 can be 82mm, 83mm, 84mm, 84.7mm, 86mm, etc. The outer diameter of the first-stage roller nose 21 can be in the range of 82mm to 86mm. Any value including the endpoint value is the outer diameter of the first-stage roller nose 21 that can be selected in the present invention. If the outer diameter of the first-stage roller nose 21 is less than 82mm, the axial force on the first-stage roller nose 21 will decrease. If the outer diameter of the first-stage roller nose 21 is greater than 86mm, the axial force on the first-stage roller nose 21 will increase. If the axial force on the first-stage roller nose 21 in the gas compression assembly 1 changes alone, it will affect the self-balance of the axial force of the gas compression assembly 1 and the reliability of the centrifugal compressor.

[0051] Exemplarily, the outer diameter of the secondary roller wheel back 32 can be 99mm, 100mm, 101.6mm, 102mm, etc. The outer diameter of the secondary roller wheel back 32 can be in the range of 99mm to 102mm. Any value including the endpoint value is the outer diameter of the secondary roller wheel back 32 that can be selected in the present invention. If the outer diameter of the secondary roller wheel back 32 is less than 99mm, the axial force on the secondary roller wheel back 32 will be reduced. If the outer diameter of the secondary roller wheel back 32 is greater than 102mm, the axial force on the secondary roller wheel back 32 will be increased. If the axial force on the secondary roller wheel back 32 in the gas compression assembly 1 changes alone, it will affect the self-balance of the axial force of the gas compression assembly 1 and the reliability of the centrifugal compressor.

[0052] Exemplarily, the outer diameter of the secondary roller nose 31 can be 78mm, 79mm, 80mm, 81.5mm, 82mm, etc. The outer diameter of the secondary roller nose 31 can be in the range of 78mm to 82mm. Any value including the endpoint value is the outer diameter of the secondary roller nose 31 that can be selected by the present invention. If the outer diameter of the secondary roller nose 31 is less than 78mm, the axial force on the secondary roller nose 31 will decrease. If the outer diameter of the secondary roller nose 31 is greater than 82mm, the axial force on the secondary roller nose 31 will increase. If the axial force on the secondary roller nose 31 in the gas compression assembly 1 changes alone, it will affect the self-balance of the axial force of the gas compression assembly 1 and the reliability of the centrifugal compressor.

[0053] Exemplarily, the outer diameter of the three-stage pressure wheel back 42 can be 108mm, 109.5mm, 110.8mm, 112mm, etc. The outer diameter of the three-stage pressure wheel back 42 can be in the range of 108mm to 112mm. Any value including the endpoint value is the outer diameter of the three-stage pressure wheel back 42 that can be selected by the present invention. If the outer diameter of the three-stage pressure wheel back 42 is less than 108mm, the axial force on the three-stage pressure wheel back 42 will be reduced. If the outer diameter of the three-stage pressure wheel back 42 is greater than 112mm, the axial force on the three-stage pressure wheel back 42 will be increased. If the axial force on the three-stage pressure wheel back 42 in the gas compression assembly 1 changes alone, it will affect the self-balance of the axial force of the gas compression assembly 1 and the reliability of the centrifugal compressor.

[0054] Exemplarily, the outer diameter of the three-stage roller nose 41 can be 58mm, 59.6mm, 61mm, 62mm, etc. The outer diameter of the three-stage roller nose 41 can be in the range of 58mm to 62mm. Any value including the endpoint value is the outer diameter of the three-stage roller nose 41 that can be selected by the present invention. If the outer diameter of the three-stage roller nose 41 is less than 58mm, the axial force on the three-stage roller nose 41 will be reduced. If the outer diameter of the three-stage roller nose 41 is greater than 62mm, the axial force on the three-stage roller nose 41 will be increased. If the axial force on the three-stage roller nose 41 in the gas compression assembly 1 changes alone, it will affect the self-balance of the axial force of the gas compression assembly 1 and the reliability of the centrifugal compressor.

[0055] Therefore, the outer diameter of the first-stage roller back 22 is between 130mm and 134mm, the outer diameter of the first-stage roller nose 21 is between 82m and 86mm, the outer diameter of the second-stage roller back 32 is between 99mm and 102mm, the outer diameter of the second-stage roller nose 31 is between 78mm and 82mm, the outer diameter of the third-stage roller back 42 is between 108mm and 112mm, and the outer diameter of the third-stage roller nose 41 is between 58mm and 62mm, so that the rotor shaft 11 can be subjected to a stable smaller axial force, so that the gas compression assembly 1 can achieve self-balance of the axial force.

[0056] In actual applications, the outer diameters of the first-stage roller nose 21, the second-stage roller nose 31, and the third-stage roller nose 41 vary slightly, and the outer diameters of the first-stage roller nose 21, the second-stage roller back 32, and the third-stage roller back 42 can be increased or decreased at the same time, so that the outer diameter D1 of the first-stage roller back 22, the outer diameter D2 of the second-stage roller back 32, and the outer diameter D3 of the third-stage roller back 42 always satisfy the relationship: D1: D2: D3 is 1: 0.77: 0.84, thereby reducing the probability that the sizes of the first-stage roller 20, the second-stage roller 30, and the third-stage roller 40 affect the axial force of the gas compression assembly 1.

[0057] In some embodiments of the present invention, the first-stage impeller 20 and the second-stage impeller 30 are closed impellers, and the third-stage impeller 40 is an open impeller.

[0058] Open impeller and closed impeller are two different types of impeller structures. The blades of open impeller are open, and the blades of closed impeller are closed. The outer edge of the blades of closed impeller is covered with a wheel cover. When the open impeller and the closed impeller are connected in series, the axial forces on the blade parts of the open impeller and the closed impeller are different. The axial force on the blade part of the open impeller can be the median of the impeller inlet pressure and the impeller outlet pressure, and the axial force on the blade part of the closed impeller can be 0.8-0.9 times the impeller outlet pressure. Therefore, the axial force on the blade part of the closed impeller is usually greater than the axial force on the blade part of the open impeller. The total axial force of a single closed impeller is usually directed to the back of the wheel, and the total axial force of a single open impeller is usually directed to the nose.

[0059] By setting the first-stage impeller 20 and the second-stage impeller 30 as closed impellers, and the third-stage impeller 40 as an open impeller, the first-stage impeller back 22 is set toward the motor 10, the second-stage impeller nose 31 is set toward the motor 10, and the third-stage impeller back 42 is set toward the motor 10, that is, the direction of the first-stage impeller 20 is the same as the direction of the second-stage impeller 30, and the direction of the third-stage impeller 40 is opposite to the direction of the first-stage impeller 20 and the direction of the second-stage impeller 30, and the outer diameter size of the first-stage impeller back 22: the outer diameter size of the second-stage impeller back 32: the outer diameter size of the third-stage impeller back 42 is 1:0.77:0.84, the self-balance of the axial force of the gas compression component 1 can be achieved, so that the rotor shaft 11 is subjected to a smaller and more stable axial force, which is beneficial to improving the stability of the gas compression component 1 during operation and the reliability of the centrifugal compressor.

[0060] As an example, the outer diameter of the first-stage roller nose 21 can be 84mm, the outer diameter of the first-stage roller wheel back 22 can be 132mm, the outer diameter of the second-stage roller nose 31 can be 80mm, the outer diameter of the second-stage roller wheel back 32 can be 101.6mm, the outer diameter of the third-stage roller nose 41 can be 59.6mm, the outer diameter of the third-stage roller wheel back 42 can be 110.8mm, the first-stage roller 20 and the second-stage roller 30 are closed impellers, and the third-stage roller 40 is an open impeller. The axial force on the first-stage roller nose 21 can be -590N, the axial force of the blade part of the first-stage roller 20 can be -2767N, the axial force on the first-stage roller wheel back 22 can be 3894N, and the total axial force on the first-stage roller 20 can be 537N. The axial force on the nose 31 of the secondary roller may be -1761N, the axial force on the blade part of the secondary roller 30 may be -2578N, the axial force on the wheel back 32 of the secondary roller may be 5642N, and the total axial force on the secondary roller 30 may be 1303N. The axial force on the nose 41 of the tertiary roller may be 2875N, the axial force on the blade part of the tertiary roller 40 may be 9846N, the axial force on the wheel back 42 of the tertiary roller may be -14604N, and the total axial force on the tertiary roller 40 may be -1883N. The total axial force on the gas compression assembly 1 may be -43N, that is, the gas compression assembly 1 is subjected to a smaller axial force toward the second end of the rotor shaft 11.

[0061] It should be noted that, along the first direction, the direction toward the first end of the rotor shaft 11 is the positive direction.

[0062] In some embodiments of the present invention, the gas pressure inside the motor 10 is higher than the gas pressure at the first-stage pressure wheel back 22 , and the gas pressure inside the motor 10 is higher than the gas pressure at the second-stage pressure wheel nose 31 .

[0063] The pressure difference between the motor 10 and the gas pressure at the first-stage pressure roller back 22 is small, and the pressure difference between the motor 10 and the gas pressure at the second-stage pressure roller nose 31 is small. By setting the gas pressure inside the motor 10 to be higher than the gas pressure at the first-stage pressure roller back 22, and the gas pressure inside the motor 10 to be higher than the gas pressure at the second-stage pressure roller nose 31, the probability of partial gas leakage from the first-stage pressure roller 20 and the second-stage pressure roller 30 to the motor 10 can be reduced, and gas loss can be reduced. If the gas inside the motor 10 leaks to the first-stage pressure roller back 22 and the second-stage pressure roller nose 31, the leaked gas can be compressed in the first-stage pressure roller 20 and the second-stage pressure roller 30, and the gas can be recycled, which is beneficial to reducing gas loss and improving the working efficiency of the gas compression component 1.

[0064] In some embodiments of the present invention, Figure 1As shown, the motor 10 also has an outer shell 12 and a stator 13. The outer shell 12 defines an installation cavity 121. The stator 13 is arranged in the installation cavity 121 and fixedly arranged on the shell side wall 122 of the outer shell 12. The rotor shaft 11 is rotatably arranged on the outer shell 12 and penetrates the outer shell 12. The shell side wall 122 is formed with an outlet hole 1221 connected to the installation cavity 121. The outlet hole 1221 is located at the end position of the shell side wall 122 away from the primary pressure wheel 20, and the electrical connection line of the stator 13 is installed in the outlet hole 1221.

[0065] The outer shell 12 may define an installation cavity 121, and the stator 13 is located in the installation cavity 121. The stator 13 may be fixedly connected to the shell side wall 122 of the outer shell 12 by bolt connection, clamping, etc. The stator 13 may be sleeved on the rotor shaft 11, and the rotor shaft 11 may rotate relative to the stator 13. At least part of the rotor shaft 11 is located in the installation cavity 121, and the rotor shaft 11 is penetrated by the outer shell 12, and the rotor shaft 11 may rotate relative to the outer shell 12. The stator 13 may be configured as a coil, and the stator 13 may be connected to an electrical connection line 131. When the stator 13 is energized, a rotating magnetic field is generated inside the motor 10. The rotor shaft 11 may be made of magnetic steel, and the weight reduction space 111 of the rotor shaft 11 may be installed with a hollow magnetic conductive core shaft. When the stator 13 is energized, a magnetic field is generated in the installation cavity 121, and the core shaft may drive the rotor shaft 11 to rotate according to the direction of the magnetic field, thereby achieving the effect of driving the rotor shaft 11 to rotate.

[0066] The shell side wall 122 may be formed with a wire outlet hole 1221, and the wire outlet hole 1221 may be connected to the installation cavity 121. The electrical connection line 131 of the stator 13 may be installed in the wire outlet hole 1221. The electrical connection line 131 may be passed through the wire outlet hole 1221 and connected to the power supply, so as to achieve the effect of energizing the stator 13. The shell side wall 122 of the outer shell 12 may be formed with a gas flow channel 60. When the gas compressed by the primary pressure wheel 20 flows out of the primary pressure wheel 20, the gas compressed by the primary pressure wheel 20 may flow to the end of the motor 10 close to the secondary pressure wheel 30 through the gas flow channel 60, so that the gas compressed by the primary pressure wheel 20 can flow into the secondary pressure wheel 30. The wire outlet hole 1221 may be located at the end of the shell side wall 122 away from the primary pressure wheel 20, which can reduce the probability that the wire outlet hole 1221 affects the flow rate of the gas compressed by the primary pressure wheel 20, reduce energy loss, and help improve the working efficiency of the gas compression assembly 1. In other words, the flow rate of the gas just compressed by the first-stage pressure wheel 20 is high. If the outlet hole 1221 is located at the end position of the shell side wall 122 close to the first-stage pressure wheel 20, the outlet hole 1221 will hinder the flow of the gas just flowing out of the first-stage pressure wheel 20, resulting in energy loss.

[0067] As an example, a flow guide component may be provided in the gas flow channel 60, and the flow guide component may be provided on the inner wall of the gas flow channel 60. The flow guide component may guide the gas compressed by the primary pressure wheel 20 to flow toward the end of the shell side wall 122 close to the secondary pressure wheel 30, so that the gas can flow stably. When the gas flows through the outlet hole 1221, it will not affect the flow rate of the gas, which is conducive to reducing energy loss. The flow guide component may be constructed as a flow guide boss protruding from the inner wall of the gas flow channel 60. There may be multiple flow guide bosses, and multiple flow guide bosses may divert the gas in the gas flow channel 60. Multiple flow guide bosses may divert the gas to the end of the shell side wall 122 close to the secondary pressure wheel 30.

[0068] In some embodiments of the present invention, Figure 1 As shown, the motor 10 also has an outer shell 12, the outer shell 12 has a mounting seat 123 opposite to the secondary pressure wheel 30, the rotor shaft 11 is penetrated by the mounting seat 123 and can rotate relative to the mounting seat 123, and a guide structure 1231 is formed on the surface of the mounting seat 123 facing the secondary pressure wheel 30, and the guide structure 1231 is configured to guide the gas compressed by the primary pressure wheel 20 to the secondary pressure wheel 30.

[0069] Along the first direction, the outer shell 12 has a mounting seat 123 opposite to the secondary pressure wheel 30, and the mounting seat 123 can be assembled with the shell side wall 122 of the outer shell 12, and the mounting seat 123 can be fixedly connected to the shell side wall 122 by means of clamping, bolt connection, etc., and the mounting seat 123 can define a mounting cavity 121 together with the shell side wall 122. The mounting seat 123 can be formed with a first through hole, and the first through hole can penetrate the mounting seat 123 along the thickness direction of the mounting seat 123. The rotor shaft 11 can be inserted into the first through hole, and the rotor shaft 11 can rotate relative to the mounting seat 123. As an example, the shaft section of the rotor shaft 11 close to the second end can be sleeved with a first air radial bearing 14, and the first air radial bearing 14 can be installed in the first through hole. The first air radial bearing 14 can be fixedly connected to the mounting seat 123 by bolts, positioning pins, etc. When the rotor shaft 11 rotates, the rotor shaft 11 can rotate relative to the first air radial bearing 14, so that the rotor shaft 11 can rotate relative to the mounting seat 123.

[0070] The mounting seat 123 can be arranged adjacent to the outlet of the gas flow channel 60, and the gas compressed by the first-level pressure wheel 20 flowing in the gas flow channel 60 can flow to the surface of the mounting seat 123 facing the second-level pressure wheel 30. The surface of the mounting seat 123 facing the second-level pressure wheel 30 can be formed with a guide structure 1231, and the guide structure 1231 can play a guide role. The guide structure 1231 can guide the gas compressed by the first-level pressure wheel 20 to the second-level pressure wheel 30. In other words, the guide structure 1231 can guide the gas flowing out of the gas flow channel 60 to the second-level pressure wheel 30, so that the gas compressed by the first-level pressure wheel 20 can flow into the second-level pressure wheel 30, which is beneficial to improve the efficiency of the gas compressed by the first-level pressure wheel 20 flowing into the second-level pressure wheel 30, so that the gas compressed by the first-level pressure wheel 20 can be compressed in the second-level pressure wheel 30.

[0071] In some embodiments of the present invention, the guide structure 1231 may include a plurality of guide blades, and the plurality of guide blades are arranged around the rotor shaft 11 along the circumference of the mounting seat 123 .

[0072] The guide structure 1231 may include a plurality of guide blades, and the plurality of guide blades may be arranged along the circumference of the mounting seat 123, and each guide blade may extend along the radial direction of the mounting seat 123. When the rotor shaft 11 is inserted into the mounting seat 123, the plurality of guide blades may be arranged around the rotor shaft 11, and the secondary compression wheel 30 is sleeved on the rotor shaft 11. The plurality of guide blades may divert the gas compressed by the primary compression wheel 20, and the plurality of guide blades may divert the gas compressed by the primary compression wheel 20 to the secondary compression wheel 30, thereby improving the efficiency of the gas compressed by the primary compression wheel 20 flowing into the secondary compression wheel 30, which is beneficial to improving the working efficiency of the gas compression assembly 1.

[0073] In some embodiments of the present invention, the motor 10 further includes an outer shell 12 , a cooling channel 1222 is formed in a shell side wall 122 of the outer shell 12 , and a heat dissipation structure is formed on the inner surface of the cooling channel 1222 .

[0074] The motor 10 also has an outer shell 12, and a cooling channel 1222 is formed in the shell side wall 122 of the outer shell 12. The cooling channel 1222 can be arranged around the mounting cavity 121, and cooling gas can flow in the cooling channel 1222. The cooling gas can be used to cool the motor 10, and the cooling gas can exchange heat with the inner surface of the cooling channel 1222. The inner surface of the cooling channel 1222 can be formed with a heat dissipation structure, and the heat dissipation structure can be constructed as a sawtooth structure protruding from the inner surface of the cooling channel 1222. By providing the heat dissipation structure, the contact area between the cooling gas and the cooling channel 1222 can be increased, which is conducive to improving the heat dissipation efficiency of the motor 10.

[0075] As an example, the cooling channel 1222 can be connected to the installation cavity 121, and the cooling gas in the cooling channel 1222 can flow into the installation cavity 121. The cooling gas can cool the stator 13 and part of the rotor shaft 11 in the installation cavity 121, thereby achieving the effect of further cooling the motor 10, which is beneficial to improving the heat dissipation performance of the gas compression component 1.

[0076] In some embodiments of the present invention, Figure 1 As shown, the shell side wall 122 may include: an inner wall 1223 and an outer wall 1224, the outer wall 1224 is sleeved on the outside of the inner wall 1223 and is detachably connected to the inner wall 1223, a first groove body is formed on the surface of the outer wall 1224 facing the inner wall 1223, and a second groove body is formed on the surface of the inner wall 1223 facing the outer wall 1224, the first groove body and the second groove body are opposite to each other to define a cooling channel 1222.

[0077] Along the radial direction of the outer shell 12, the outer wall 1224 can be sleeved on the outer side of the inner wall 1223, and the outer wall 1224 can be connected to the inner wall 1223 by means of clamping, bolt connection, etc., and the outer wall 1224 is detachably connected to the inner wall 1223. A first groove is formed on the surface of the outer wall 1224 facing the inner wall 1223, and the first groove is recessed toward the outer wall 1224. A second groove is formed on the surface of the inner wall 1223 facing the outer wall 1224, and the second groove is recessed toward the inner wall 1223. The first groove can be arranged opposite to the second groove, and the first groove can define a cooling channel 1222 together with the second groove, and cooling gas can flow in the cooling channel 1222. By setting the outer wall 1224 to be detachably connected to the inner wall 1223, it is convenient to process the heat dissipation structure on the inner surface of the cooling channel 1222, which is conducive to reducing production costs.

[0078] In some embodiments of the present invention, Figure 1 and Figure 3As shown, the gas compression assembly 1 for a centrifugal compressor may also include: a shaft seal 50, the motor 10 also has an outer shell 12, the outer shell 12 has a mounting seat 123 opposite to the secondary pressure wheel 30, the mounting seat 123 is formed with a mounting through hole 1232, the rotor shaft 11 is passed through the mounting through hole 1232 and is rotatable relative to the mounting seat 123, the shaft seal 50 is sleeved on the rotor shaft 11 and installed in the mounting through hole 1232, the outer wall of the shaft seal 50 is formed with one of the sealing boss 51 and the sealing groove 1233, the surface of the outer wall of the mounting through hole 1232 facing the shaft seal 50 is formed with the other of the sealing boss 51 and the sealing groove 1233, the sealing boss 51 is assembled on the sealing groove 1233 and is gap-matched with the inner wall of the sealing groove 1233, there are multiple sealing bosses 51 and sealing grooves 1233, and the sealing bosses 51 and the sealing grooves 1233 are arranged in a stepped manner along the axial direction of the rotor shaft 11.

[0079] Along the first direction, the outer shell 12 has a mounting seat 123 opposite to the secondary pressure wheel 30, and the mounting seat 123 can be assembled with the shell side wall 122 of the outer shell 12, and the mounting seat 123 can be fixedly connected with the shell side wall 122 by means of clamping, bolt connection, etc., and the mounting seat 123 can define a mounting cavity 121 together with the shell side wall 122. The mounting seat 123 can be formed with a mounting through hole 1232 (i.e., the first through hole in the above embodiment), and the mounting through hole 1232 can penetrate the mounting seat 123 along the thickness direction of the mounting seat 123. The rotor shaft 11 can be inserted into the mounting through hole 1232, and the rotor shaft 11 can rotate relative to the mounting seat 123. The shaft seal 50 can be made of aluminum alloy material, and the shaft seal 50 can be sleeved on the rotor shaft 11, and the shaft seal 50 can be interference fit with the rotor shaft 11. When the rotor shaft 11 is passed through the installation through hole 1232, the shaft seal 50 can be located in the installation through hole 1232, and the shaft seal 50 can reduce the probability of gas in the installation cavity 121 leaking to the secondary pressure wheel 30. The outer wall of the shaft seal 50 is formed with a sealing boss 51 extending along the circumference of the shaft seal 50 and one of the sealing grooves 1233, and the surface of the outer wall of the installation through hole 1232 facing the shaft seal 50 is formed with the other of the sealing boss 51 and the sealing groove 1233. The embodiment of the present application is described by taking the outer wall of the shaft seal 50 formed with the sealing boss 51 and the surface of the outer wall of the installation through hole 1232 facing the shaft seal 50 as an example.

[0080] The sealing boss 51 can be assembled in the sealing groove 1233. By arranging the sealing boss 51 and the sealing groove 1233 to be assembled in coordination, the probability of the gas in the installation cavity 121 flowing to the secondary compression wheel 30 can be reduced. When the rotor shaft 11 rotates, the rotor shaft 11 can drive the shaft seal 50 to rotate relative to the mounting seat 123. There can be a gap between the sealing boss 51 and the inner wall of the sealing groove 1233. A small amount of gas in the installation cavity 121 can flow into the gap between the sealing boss 51 and the inner wall of the sealing groove 1233. The gas can flow through the first air radial bearing 14, so that the first air radial bearing 14 can be cooled. If the gas flows to the secondary compression wheel 30, the gas can be compressed in the secondary compression wheel 30, so that the gas is recycled and reused, and the gas loss is reduced.

[0081] There may be multiple sealing bosses 51, and there may be multiple sealing grooves 1233. Multiple sealing bosses 51 may be arranged one-to-one with multiple sealing grooves 1233, and each sealing boss 51 has a sealing groove 1233 that is assembled and matched with it. Multiple sealing bosses 51 may be arranged in a stepped manner along the axial direction of the rotor shaft 11, and multiple sealing grooves 1233 may be arranged in a stepped manner along the axial direction of the rotor shaft 11, which can extend the flow path of the gas leaking from the installation cavity 121 and reduce the gas flow to the secondary pressure wheel 30.

[0082] In some embodiments of the present invention, the end surface of the shaft seal 50 facing away from the first-stage pressure wheel 20 is constructed as a first abutment surface 52, and the inner surface of the mounting through hole 1232 is formed with a second abutment surface 1234. The first abutment surface 52 and the second abutment surface 1234 are opposite to each other along the axial direction of the rotor shaft 11, and the first abutment surface 52 and the second abutment surface 1234 are in abutment with each other.

[0083] The first abutment surface 52 and the second abutment surface 1234 are arranged opposite to each other along the first direction. The abutment between the first abutment surface 52 and the second abutment surface 1234 can improve the sealing between the shaft seal 50 and the mounting seat 123, which is beneficial to further reduce the gas flow flowing to the secondary pressure wheel 30 and improve the stability of the installation of the shaft seal 50.

[0084] In some embodiments of the present invention, the gas compression assembly 1 for a centrifugal compressor may further include: a partition plate, which is sleeved on the rotor shaft 11 and located between the secondary pressure wheel 30 and the tertiary pressure wheel 40 to separate the secondary pressure wheel 30 and the tertiary pressure wheel 40.

[0085] A partition plate may be provided between the secondary pressure wheel 30 and the tertiary pressure wheel 40, and the partition plate may separate the secondary pressure wheel 30 and the tertiary pressure wheel 40. The partition plate may be sleeved on the rotor shaft 11, thereby reducing the probability of gas in the tertiary pressure wheel 40 flowing into the secondary pressure wheel 30, which is beneficial to improving the safety of the operation of the gas compression assembly 1.

[0086] The partition plate can be assembled with the secondary pressure wheel 30, and the partition plate can be assembled with the tertiary pressure wheel 40. As an example, the partition plate has a first side surface and a second side surface opposite to each other in a first direction, and the first side surface can be formed with one of the first mounting boss and the first mounting groove 321, and the surface of the secondary pressure wheel back 32 facing the partition plate can be formed with the other of the first mounting boss and the first mounting groove 321, and the first mounting boss can be assembled in the first mounting groove 321, and the first mounting boss can be loosely matched with the first mounting groove 321. The embodiment of the present application is described by taking the first side surface having the first mounting boss formed thereon and the surface of the secondary pressure wheel back 32 facing the partition plate having the first mounting groove 321 formed thereon as an example, and the first mounting boss can be constructed as an annular structure, and the first mounting groove 321 can be constructed as an annular groove. There can be multiple first mounting bosses, and the multiple first mounting bosses can be arranged in sequence along the radial direction of the partition plate. There can be multiple first mounting grooves 321, and the multiple first mounting grooves 321 can be arranged in sequence along the radial direction of the secondary pressure wheel back 32. The plurality of first mounting bosses may be arranged in one-to-one correspondence with the plurality of first mounting grooves 321 , and each first mounting boss has a first mounting groove 321 that is assembled and matched with the first mounting boss.

[0087] One of the second mounting boss and the second mounting groove 421 is formed on the second side surface, and the other of the second mounting boss and the second mounting groove 421 is formed on the surface of the third-stage pressure wheel back 42 facing the partition plate. The second mounting boss can be assembled in the second mounting groove 421, and the second mounting boss can be loosely matched with the second mounting groove 421. The embodiment of the present application is described by taking the second mounting boss formed on the second side surface and the second mounting groove 421 formed on the surface of the third-stage pressure wheel back 42 facing the partition plate as an example. The second mounting boss can be constructed as an annular structure, the second mounting groove 421 can be constructed as an annular groove, and there can be multiple second mounting bosses, and multiple second mounting bosses can be arranged in sequence along the radial direction of the partition plate. There can be multiple second mounting grooves 421, and multiple second mounting grooves 421 can be arranged in sequence along the radial direction of the secondary pressure wheel back 32. Multiple second mounting bosses can be arranged one by one with multiple second mounting grooves 421, and each second mounting boss has a second mounting groove 421 that is matched and assembled with it.

[0088] The inner surface of the partition plate along the circumference of the partition plate is formed with one of the third mounting boss and the third mounting groove extending along the circumference of the rotor shaft 11, and the third mounting boss and the other of the third mounting groove are formed on the surface of the third-stage pressure wheel 40 facing the partition plate in the circumference direction. The third mounting boss can be assembled in the third mounting groove, and the third mounting boss can be loosely matched with the third mounting groove. The embodiment of the present application is described by taking the third mounting boss formed on the inner surface of the partition plate along the circumference of the partition plate and the third mounting groove formed on the surface of the third-stage pressure wheel 40 facing the partition plate in the circumference direction as an example. There are multiple third mounting bosses and multiple third mounting grooves, and multiple third mounting bosses can be set one-to-one with multiple third mounting grooves. Both the third mounting boss and the third mounting groove are arranged in a stepped manner along the axial direction of the rotor shaft 11.

[0089] By setting a clearance fit between the first mounting boss and the first mounting groove 321, and a clearance fit between the second mounting boss and the second mounting groove 421, the secondary pressure wheel 30 and the tertiary pressure wheel 40 can rotate smoothly relative to the partition plate, which is beneficial to reduce the friction between the secondary pressure wheel 30, the tertiary pressure wheel 40 and the partition plate, and is beneficial to extend the service life of the partition plate.

[0090] In some embodiments of the present invention, the motor 10 may include an air thrust bearing 70, a second air radial bearing 15, a back plate 80 and an end wall 90. The end wall 90 may be arranged opposite to and spaced from the mounting seat 123 along the first direction. The mounting seat 123, the end wall 90 and the shell side wall 122 together define a mounting cavity 121. The end wall 90 may be integrally formed with the inner side wall 1223. The end wall 90 may be formed with a second through hole 91. The rotor shaft 11 may be inserted into the second through hole 91. The second air radial bearing 15 may be sleeved on the shaft section of the rotor shaft 11 close to the first end. The second air radial bearing 15 may be located in the second through hole 91. The second air radial bearing 15 may be fixedly connected to the end wall 90 by bolts, positioning pins, etc. When the rotor shaft 11 rotates, the rotor shaft 11 may rotate relative to the second air radial bearing 15, so that the rotor shaft 11 may rotate relative to the end wall 90.

[0091] The back plate 80 may be arranged on the side of the end wall 90 away from the mounting seat 123, the back plate 80 may be fixedly connected to the end wall 90 by bolts, the back plate 80 may be formed with a third through hole 81, the primary pressure wheel 20 may be arranged on the side of the back plate 80 away from the end wall 90, at least a portion of the primary pressure wheel 20 may be passed through the third through hole 81, and the primary pressure wheel back 22 may abut against the back plate 80. At least a portion of the end wall 90 may be spaced apart from the back plate 80, and a gap is formed between at least a portion of the end wall 90 and the back plate 80. Along the first direction, an air thrust bearing 70 may be arranged on the side of the second air radial bearing 15 away from the first air radial bearing 14, and there may be two air thrust bearings 70, one of which may abut against the end wall 90, and the other air thrust bearing 70 may abut against the back plate 80, and the two air thrust bearings 70 are located in the gap between the end wall 90 and the back plate 80. The two air thrust bearings 70 can be fixed on the end wall 90 and the back plate 80 respectively by positioning pins. A thrust plate 71 can be arranged between the two air thrust bearings 70. The two air thrust bearings 70 are spaced apart, and the air thrust bearings 70 can play the role of supporting the rotor shaft 11 and reducing the axial movement of the rotor shaft 11. By arranging the two air thrust bearings 70 in the gap between the end wall 90 and the back plate 80, it is helpful to reduce the length dimension of the motor 10 along the first direction, and it is helpful to reduce the space occupied by the motor 10.

[0092] As an example, the inner wall of the third through hole 81 is formed with one of the fourth mounting boss and the fourth mounting groove extending circumferentially along the back plate 80, and the surface of the first-stage pressure wheel 20 opposite to the inner wall of the third through hole 81 along the circumference of the third through hole 81 is formed with the other of the fourth mounting boss and the fourth mounting groove, and the fourth mounting boss can be assembled in the fourth mounting groove, and the fourth mounting boss can be loosely matched with the fourth mounting groove. The embodiment of the present application is described by taking the fourth mounting groove formed on the inner wall of the third through hole 81 and the fourth mounting boss formed on the surface of the first-stage pressure wheel 20 opposite to the inner wall of the third through hole 81 along the circumference of the third through hole 81 as an example, the fourth mounting boss and the fourth mounting groove can both be multiple, multiple fourth mounting bosses can be set one-to-one with multiple fourth mounting grooves, and the fourth mounting boss and the fourth mounting groove can be arranged in sequence along the first direction.

[0093] The centrifugal compressor according to the second embodiment of the present invention comprises the gas compression assembly 1 in the above embodiment.

[0094] According to the centrifugal compressor of the embodiment of the present application, the use of the gas compression assembly 1 in the above embodiment can reduce the axial force on the centrifugal compressor, which is beneficial to improving the reliability of the centrifugal compressor.

[0095] Other structures and operations of the gas compression assembly 1 and the centrifugal compressor according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0097] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A gas compression assembly for a centrifugal compressor, characterized in that: include: An electric motor (10), the electric motor (10) having a rotor shaft (11); A first-stage pressure wheel (20), the first-stage pressure wheel (20) being fixedly arranged at the first end of the rotor shaft (11), the first-stage pressure wheel (20) comprising a first-stage pressure wheel nose (21) and a first-stage pressure wheel back (22), the first-stage pressure wheel nose (21) being located on a side of the first-stage pressure wheel back (22) facing away from the motor (10); A secondary pressure wheel (30), the secondary pressure wheel (30) is fixedly arranged at the second end of the rotor shaft (11), the secondary pressure wheel (30) has a secondary pressure wheel nose (31) and a secondary pressure wheel back (32), the secondary pressure wheel back (32) is located on the side of the secondary pressure wheel nose (31) away from the motor (10), and the secondary pressure wheel (30) is used to compress the gas compressed by the primary pressure wheel (20); A three-stage pressure wheel (40), the three-stage pressure wheel (40) is fixedly arranged at the second end of the rotor shaft (11) and is located on the side of the two-stage pressure wheel (30) away from the motor (10), the three-stage pressure wheel (40) has a three-stage pressure wheel nose (41) and a three-stage pressure wheel back (42), the three-stage pressure wheel nose (41) is located on the side of the three-stage pressure wheel back (42) away from the motor (10), and the three-stage pressure wheel (40) is used to compress the gas compressed by the two-stage pressure wheel (30).

2. The gas compression assembly according to claim 1, characterized in that The outer diameter dimension of the first-stage pressing wheel back (22) is D1, the outer diameter dimension of the second-stage pressing wheel back (32) is D2, and the outer diameter dimension of the third-stage pressing wheel back (42) is D3, satisfying the relationship: D1:D2:D3 is 1:0.77:0.

84.

3. The gas compression assembly according to claim 2, characterized in that The outer diameter of the first-stage pressure wheel nose (21) is D4, which satisfies the relationship: 130mm≤D1≤134mm, 82mm≤D4≤86mm; The outer diameter of the secondary pressure wheel nose (31) is D5, which satisfies the relationship: 99mm≤D2≤102mm, 78mm≤D5≤82mm; The outer diameter dimension of the three-stage pressure wheel nose (41) is D6, which satisfies the relationship: 108mm≤D3≤112mm, 58mm≤D6≤62mm.

4. The gas compression assembly according to claim 1, characterized in that The first-stage impeller (20) and the second-stage impeller (30) are closed impellers, and the third-stage impeller (40) is an open impeller.

5. The gas compression assembly according to claim 1, characterized in that The gas pressure inside the motor (10) is higher than the gas pressure at the back of the first-stage pressure wheel (22), and the gas pressure inside the motor (10) is higher than the gas pressure at the nose of the second-stage pressure wheel (31).

6. The gas compression assembly according to any one of claims 1 to 5, characterized in that: The motor (10) further comprises an outer shell (12) and a stator (13); the outer shell (12) defines a mounting cavity (121); the stator (13) is arranged in the mounting cavity (121) and fixedly arranged on a shell side wall (122) of the outer shell (12); the rotor shaft (11) is rotatably arranged on the outer shell (12) and penetrates the outer shell (12); the shell side wall (122) is formed with a wire outlet hole (1221) communicating with the mounting cavity (121); the wire outlet hole (1221) is located at an end position of the shell side wall (122) away from the primary pressure wheel (20); and an electrical connection line of the stator (13) is installed in the wire outlet hole (1221).

7. The gas compression assembly according to any one of claims 1 to 5, characterized in that: The motor (10) further comprises an outer shell (12), wherein the outer shell (12) comprises a mounting seat (123) opposite to the secondary pressure wheel (30), wherein the rotor shaft (11) is inserted through the mounting seat (123) and is rotatable relative to the mounting seat (123), and a guide structure (1231) is formed on the surface of the mounting seat (123) facing the secondary pressure wheel (30), wherein the guide structure (1231) is configured to guide the gas compressed by the primary pressure wheel (20) to the secondary pressure wheel (30).

8. The gas compression assembly according to any one of claims 1 to 5, characterized in that: The motor (10) further comprises an outer shell (12), a cooling channel (1222) being formed in a shell side wall (122) of the outer shell (12), and a heat dissipation structure being formed on an inner surface of the cooling channel (1222).

9. The gas compression assembly according to any one of claims 1 to 5, characterized in that: Also includes: A partition plate is sleeved on the rotor shaft (11) and is located between the secondary pressure wheel (30) and the tertiary pressure wheel (40) so as to separate the secondary pressure wheel (30) from the tertiary pressure wheel (40).

10. A centrifugal compressor, characterized in that: Comprising a gas compression assembly (1) according to any one of claims 1-9.

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