A magnetic levitation centrifugal heat pump compressor operating in wide frequency

Abstract

The present application relates to the field of centrifugal compressor, especially to a wide frequency conversion operation magnetic suspension centrifugal heat pump compressor. The compressor is internally provided with a cooling channel, the cooling channel comprises a motor cooling channel, a turning channel and a discharge channel, the motor cooling channel, the turning channel and the discharge channel are sequentially communicated; when the refrigerant flows from the motor cooling channel, then passes through the turning channel and the discharge channel, finally the refrigerant flows out from the suction port channel and mixes with the low-temperature and low-pressure refrigerant gas in the first gas inlet to form superheated steam, the superheated steam enters the gas circulation structure through the first gas inlet to actively participate in the circulation process of the compressor. The compressor is communicated with the gas circulation structure of the compressor through the cooling channel, so that the structure of the compressor is more compact, the external connection is reduced, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of centrifugal compressors, and more particularly to a magnetic levitation centrifugal heat pump compressor with wide-range variable frequency operation. Background Technology

[0002] A centrifugal compressor consists of a rotor, stator, and bearings. The impeller and other components are mounted on a main shaft to form the rotor, which is supported by bearings and driven by a power unit to rotate at high speed. The stator includes components such as the casing, diaphragms, seals, inlet chamber, and volute. Fixed elements such as diffusers, bends, and return channels are formed between the diaphragms. A centrifugal compressor with only one impeller is called a single-stage centrifugal compressor, while one with two or more impellers is called a multi-stage centrifugal compressor. Each stage consists of the impeller and subsequent channels such as diffusers. The impeller is a key component of a centrifugal compressor and comes in three types: closed, semi-open, and open. An open impeller lacks a cover and disc; the impeller sits on the shaft. When the impeller rotates at high speed, due to the interaction of forces between the blades and the gas, primarily centrifugal force, the gas is drawn in from the center of the impeller and flows along the blade channels (the passages between the blades) to the outer edge of the impeller. The impeller performs work on the gas, giving it energy and increasing its pressure and velocity. Then, the gas flows through channels such as diffusers, where its velocity decreases and its pressure further increases—that is, kinetic energy is converted into pressure energy. The gas flowing out of the diffuser enters the volute and is delivered out, or it passes through the bend and return flower to enter the next stage for further compression.

[0003] Currently, centrifugal compressors are gradually adopting oil-free technology to replace the original oil lubrication, thereby eliminating the lubrication system. However, the operating range of existing centrifugal compressors is relatively narrow, basically only meeting the needs of air conditioning chilled water operation. Those capable of meeting the high-pressure ratio requirements of heat pumps, air-cooled chilled water, and ice storage are mostly gear-speed centrifugal compressors with oil-based systems. These compressors use asynchronous motors and gear pairs to increase speed, resulting in transmission losses and low overall efficiency. The bearings are mostly oil-lubricated, requiring an oil lubrication system, which is complex and reduces reliability. Motor cooling often involves refrigerant gas or liquid entering the motor housing to cool the motor and then directly discharging it back to the evaporator through the motor housing's return port. This design results in a less compact internal structure, requiring external connections and increasing costs. It also reduces the heat exchange capacity of the evaporator and lowers system performance to some extent. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a wide-range variable frequency magnetic levitation centrifugal heat pump compressor. This compressor optimizes and integrates more rational aerodynamic design technology and permanent magnet variable frequency technology, thereby increasing the compressor's maximum operating pressure ratio and operating range. This allows it to operate in heat pump mode, air-cooled chilled water mode, industrial chilled water mode, ice storage mode, etc., and can also handle air conditioning chilled water mode. The use of magnetic levitation bearing technology enables oil-free operation of the system, and a clever cooling channel design connects the refrigerant gas cooled by the motor to the compressor's intake chamber, making the compressor structure more compact, reducing piping connections to external systems, lowering costs, and improving overall efficiency to a certain extent.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A wide-range variable frequency magnetic levitation centrifugal heat pump compressor includes a housing, a gas circulation structure, and a motor assembly. The gas circulation structure and motor assembly are both housed inside the housing. The housing includes an intake housing, a primary volute, a motor housing, and a secondary volute. The secondary and primary volutes are fixedly connected to the left and right ends of the motor housing, respectively, and the intake housing is fixedly located at the right end of the primary volute. The gas circulation structure includes a first air inlet, which is located on the intake housing and communicates with the primary volute. The motor assembly includes a main shaft, a first bearing, a second bearing, and a stator. The second and first bearings are respectively located at the left and right ends of the motor housing, the main shaft is mounted in the middle of the first and second bearings, and the stator is located in the middle of the main shaft.

[0007] The compressor is equipped with a cooling channel, which includes a motor cooling channel, a deflection channel, and a discharge channel, all of which are sequentially connected. The motor cooling channel includes a liquid inlet, a spiral groove, and a liquid outlet, all located in the middle of the motor housing. The spiral groove surrounds the outer ring of the stator, and the longitudinally arranged liquid inlet and the transversely arranged liquid outlet are respectively connected to both ends of the spiral groove. The deflection channel includes a first channel, a first cavity, and a second channel, all sequentially connected. The first cavity is located between the second bearing and the motor housing. The second channel is axially located inside the second bearing, and the first channel is located on the outer diameter of the second bearing and axially penetrates through it. The bearing has a first channel whose right end is connected to the left end of the liquid supply outlet. The discharge channel includes a rotor air gap, a third channel, a volute channel one, and an intake channel connected in sequence. The rotor air gap is located between the stator and the main shaft. The third channel is axially located inside the first bearing. The volute channel one is located inside the first-stage volute. The intake channel is located on the intake housing. The rotor air gap is connected to the second channel. The intake channel is connected to the first intake port of the compressor. After the refrigerant flows through the cooling channel, it mixes with the low-temperature, low-pressure refrigerant gas in the first intake port to form superheated steam. The hot steam then enters the compressor through the first intake port. Thus, this part of the refrigerant carries the heat from cooling the motor and actively participates in the compressor's cycle process.

[0008] Preferably, the gas circulation structure further includes an intake assembly, an exhaust assembly, and a gas transmission channel;

[0009] The intake assembly includes a first impeller and a first-stage diffuser. The first impeller is disposed inside the first air inlet, and its larger surface area side is fixedly connected to the right end of the main shaft by bolts. The first-stage diffuser is sandwiched between the first bearing and the first impeller and inserted into the outer diameter of the right end of the main shaft. The first volute is provided with a first-stage intake port that passes through the first-stage diffuser and communicates with the first impeller. The first-stage intake port is connected to one end of the gas transmission channel.

[0010] The exhaust assembly includes a second impeller and a second-stage diffuser. The second impeller is disposed inside the second-stage volute, and its larger surface area side is fixedly connected to the left end of the main shaft by bolts. The second-stage diffuser is sandwiched between the second bearing and the second impeller and inserted into the outer diameter of the left end of the main shaft. The second volute is provided with a second-stage exhaust port that passes through the second-stage diffuser and communicates with the second impeller. The second-stage exhaust port communicates with the outer surface of the second-stage volute.

[0011] The second air inlet is provided on the secondary volute, the second impeller is disposed in the second air inlet, and the other end of the gas transmission channel is connected to the second air inlet.

[0012] Preferably, the first air inlet is also provided with an adjustable guide vane, which is fixedly installed in the first-stage volute and located at the right end of the first impeller.

[0013] Preferably, the outer surface of the first impeller is provided with a primary sealing cover, and the outer surface of the second impeller is provided with a secondary sealing cover.

[0014] Preferably, both the primary diffuser and the secondary diffuser are provided with sealing tooth structures at the ends of the main shaft, and both the primary sealing wheel cover and the secondary sealing wheel cover are also provided with sealing tooth structures.

[0015] Preferably, a gap is provided between the primary sealing wheel cover and the first impeller, and a gap is also provided between the secondary sealing wheel cover and the second impeller, and the size of the gap is 0.1mm-0.5mm.

[0016] Preferably, the secondary volute is provided with an air supply port that communicates with the second air inlet.

[0017] Preferably, a flange is provided on the left end of the secondary volute, the middle part of the flange is aligned with the inlet of the second air inlet, and a gap is provided between the flange and the second air inlet, the gap being 0.5mm-3mm.

[0018] In summary, the advantages of this invention are:

[0019] 1. This compressor adopts a closed-loop three-dimensional impeller design, combined with permanent magnet variable frequency motor technology and magnetic levitation bearing technology, to achieve wide-range speed regulation, high speed, and large operating pressure ratio, greatly expanding the compressor's operating range and enabling its application in various fields. The magnetic levitation bearing technology allows the compressor to operate without oil, eliminating the need for an oil circulation system and making it more energy-efficient and environmentally friendly.

[0020] 2. The first and second impellers are respectively arranged at both ends of the main shaft to reduce axial force and facilitate axial control of the compressor.

[0021] 3. The impeller cover and disc are equipped with sealing tooth structures. The diffuser structure is simple and reliable, and the structure is reasonable and easy to assemble.

[0022] 4. The motor is cooled by refrigerant, and the cooling channel is connected to the gas circulation structure of the compressor. When the liquid refrigerant cools the motor through the cooling channel, it flows through the suction port channel and mixes with the low-temperature and low-pressure refrigerant gas in the first intake port to form superheated vapor. The hot vapor then enters the compressor through the first intake port. Thus, this part of the refrigerant carries the heat from cooling the motor and actively participates in the compressor's circulation process, realizing internal circulation of the compressor. This helps to increase the superheat of the compressor's first intake port, effectively prevents liquid from being carried in the compressor's suction, and reduces the compressor's return gas pipeline. It has a high degree of integration and a more compact structural layout. Attached Figure Description

[0023] Figure 1 A schematic diagram of a magnetic levitation centrifugal heat pump compressor with wide-range variable frequency operation;

[0024] Figure 2 This is a cross-sectional view of the compressor;

[0025] Figure 3 This is a cross-sectional view of the compressor's cooling passage;

[0026] Figure 4 This is a partial cross-sectional view of the first impeller;

[0027] Figure 5 This is a partial cross-sectional view of the second impeller;

[0028] Reference numerals: 1. Outer casing; 2. Gas circulation structure; 3. Motor assembly; 11. Intake casing; 12. First-stage volute; 13. Second-stage volute; 14. Air inlet; 15. Flange; 16. Gap; 21. First air inlet; 22. Intake assembly; 23. Exhaust assembly; 24. Gas transmission channel; 25. Adjustable guide vane; 26. Sealing tooth structure; 27. Gap; 31. Motor casing; 32. Main shaft; 33. First bearing; 34. Second bearing; 35. Stator; 41. Supply... 42. Liquid inlet; 43. Spiral groove; 44. Liquid supply outlet; 45. First channel; 46. First cavity; 47. Second channel; 48. Rotor air gap; 49. Third channel; 40. Volute channel one; 51. Inlet channel; 221. First impeller; 222. First-stage diffuser; 223. First-stage intake port; 224. First-stage sealing wheel cover; 231. Second impeller; 232. Second-stage diffuser; 233. Second air inlet; 234. Second-stage outlet; 235. Second-stage sealing wheel cover. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] It should also be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] like Figures 1 to 5 As shown, a wide-range variable frequency magnetic levitation centrifugal heat pump compressor includes a housing 1, a gas circulation structure 2, and a motor assembly 3. The gas circulation structure 2 and the motor assembly 3 are both housed inside the housing 1. The housing 1 includes an intake housing 11, a primary volute 12, a motor housing 31, and a secondary volute 13. The secondary volute 13 and the primary volute 12 are fixedly connected to the left and right ends of the motor housing 31, respectively. The intake housing 11 is fixedly located at the right end of the primary volute 12. The gas circulation structure 2 includes a first air inlet 21, which is located on the intake housing. The motor assembly 3 is connected to the first-stage volute 12 on the body 11. The motor assembly 3 includes a main shaft 32, a first bearing 33, a second bearing 34, and a stator 35. The second bearing 34 and the first bearing 33 are respectively located at the left and right ends of the motor housing 31. The main shaft 32 is mounted in the middle of the first bearing 33 and the second bearing 34, and the stator 35 is located in the middle of the main shaft 32. The main shaft is a rotor made of permanent magnet material, and permanent magnet frequency conversion technology enables the rotor to rotate at high speed, resulting in high efficiency, high torque, and efficient speed regulation over a wide range, greatly increasing the compressor's operating range. The first and second bearings are magnetic levitation bearings, using magnetic levitation technology to support the main shaft for high-speed rotation without contact, eliminating the need for lubricating oil for lubrication and cooling.

[0034] The compressor is equipped with a cooling channel, which includes a motor cooling channel, a steering channel, and a discharge channel, all of which are sequentially connected. The motor cooling channel includes a liquid inlet 41, a spiral groove 42, and a liquid outlet 43. These are all located in the middle of the motor housing 31. The spiral groove 42 surrounds the outer ring of the stator 35. The longitudinally arranged liquid inlet 41 and the transversely arranged liquid outlet 43 are respectively connected to both ends of the spiral groove 42. The steering channel includes a first channel 44, a first cavity 45, and a second channel 46, all sequentially connected. The first cavity 45 is located between the second bearing 34 and the motor housing 31. The second channel 46 is axially located inside the second bearing 34. The first channel 44 is located on the outer diameter of the second bearing 34 and axially penetrates it. The right end of the first channel 44 is connected to the left end of the liquid outlet 43. The discharge channel... The compressor comprises a rotor air gap 47, a third channel 48, a volute channel 49, and an intake channel 50, connected in sequence. The rotor air gap 47 is located between the stator 35 and the main shaft 32. The third channel 48 is axially positioned inside the first bearing 33. The volute channel 49 is located inside the first-stage volute 12. The intake channel 50 is located on the intake housing 11. The rotor air gap 47 is connected to the second channel 46, and the intake channel 50 is connected to the first intake port 21 of the compressor. After flowing through the cooling channel, the refrigerant mixes with the low-temperature, low-pressure refrigerant gas in the first intake port 21 to form superheated vapor. This hot vapor then enters the compressor through the first intake port 21. Thus, this portion of the refrigerant carries the heat from cooling the motor and actively participates in the compressor's circulation process, achieving internal circulation within the compressor. This increases the superheat at the first intake port, effectively prevents liquid carryover during compressor intake, reduces the compressor's return gas pipeline, and results in a high degree of integration and a more compact structural layout.

[0035] The gas circulation structure 2 further includes an intake assembly 22, an exhaust assembly 23, and a gas transmission channel 24. The intake assembly 22 includes a first impeller 221 and a first-stage diffuser 222. The first impeller 221 is disposed inside the first air inlet 21, and its larger surface area side is fixedly connected to the right end of the main shaft 32 by bolts. The first-stage diffuser 222 is sandwiched between the first bearing 33 and the first impeller 221 and is inserted into the outer diameter of the right end of the main shaft 32. The first volute is provided with a first-stage intake port 223 that passes through the first-stage diffuser 222 and communicates with the first impeller 221. The first-stage intake port 223 is connected to one end of the gas transmission channel 24. When gas flows into the first-stage intake port 223, it passes through the first impeller 221 and the first-stage diffuser 222. After being heated and pressurized, it passes through the first-stage intake port. The gas is delivered to the gas transmission channel 24 via port 223. The exhaust assembly 23 includes a second impeller 231 and a secondary diffuser 232. The second impeller 231 is disposed inside the secondary volute 13, and its larger surface area side is fixedly connected to the left end of the main shaft 32 by bolts. The secondary diffuser 232 is sandwiched between the second bearing 34 and the second impeller 231 and inserted into the outer diameter of the left end of the main shaft 32. The second volute is provided with a secondary outlet 234 that passes through the secondary diffuser 232 and communicates with the second impeller 231. The secondary outlet 234 communicates with the outer surface of the secondary volute 13. The secondary volute 13 is provided with a second inlet 233, and the second impeller 231 is disposed inside the second inlet 233. The other end of the gas transmission channel 24 is connected to the second inlet 233. An adjustable guide vane 25 is also provided inside the first air inlet 21. The adjustable guide vane 25 is fixedly installed inside the first-stage volute 12 and located at the right end of the first impeller 221. A first-stage sealing wheel cover 224 is provided on the outer surface of the first impeller 221, and a second-stage sealing wheel cover 235 is provided on the outer surface of the second impeller 231. Both the first-stage diffuser 222 and the second-stage diffuser 232 are provided with sealing tooth structures 26 at the ends of the main shaft 32. The first-stage sealing wheel cover 224 and the second-stage sealing wheel cover 235 are also provided with sealing tooth structures 26. A gap 27 is provided between the first-stage sealing wheel cover 224 and the first impeller 221, and a gap 27 is also provided between the second-stage sealing wheel cover 235 and the second impeller 231. The size of the gap 27 is 0.1mm-0.5mm. An air inlet 14 communicating with the second air inlet 233 is provided on the second volute 13. A flange 15 is provided on the left end of the secondary volute 13. The middle part of the flange 15 is aligned with the inlet of the second air inlet 233, and a gap 16 is provided between the flange 15 and the second air inlet 233. The gap 16 ranges from 0.5mm to 3mm.The first impeller 221 and the second impeller 231 adopt a closed three-dimensional flow blade design, which is more efficient and quieter. The first impeller 221 and the second impeller 231 are respectively arranged at both ends of the main shaft, which has the function of balancing axial force and making axial control easier. The first impeller 221 and the second impeller 231 also adopt a high pressure ratio design, with a maximum operating pressure ratio of 6.0, which is much higher than that of similar products. It can operate in heat pump mode, air-cooled chilled water mode, industrial chilled water mode, ice storage mode, etc., and can also be used for air conditioning chilled water mode, which greatly increases the operating range of the compressor.

[0036] like Figures 1 to 3 As shown, this compressor employs magnetic levitation bearing technology and permanent magnet variable frequency motor drive technology. This not only eliminates the need for an oil system, significantly increasing unit reliability, but also eliminates the need for regular oil checks, making maintenance simple and convenient. The magnetic levitation motor assembly 3 includes a motor housing 31, a main shaft 32, a first bearing 33, a second bearing 34, and a stator 35. The second bearing 34 and the first bearing 33 are respectively located at the left and right ends of the motor housing 31. The main shaft 32 is mounted in the middle of the first bearing 33 and the second bearing 34, and the stator 35 is located in the middle of the main shaft 32.

[0037] like Figure 3 As shown, the cooling channel is located inside the compressor to cool the internal motor. The cooling channel includes a motor cooling channel, a deflection channel, and a discharge channel connected in sequence. These three channels effectively cool the motor. The motor cooling channel includes a liquid supply inlet 41, a spiral groove 42, and a liquid supply outlet 43. All three are located in the middle of the motor housing 31. The spiral groove 42 surrounds the outer ring of the stator 35. The liquid supply inlet 41 is longitudinally positioned on the motor housing 31 for receiving refrigerant liquid. The liquid supply outlet 43 is transversely positioned on the motor housing 31 for transferring refrigerant liquid to other channels. The liquid supply outlet 43 and the liquid supply inlet 41 are connected to both ends of the spiral groove 42. When refrigerant liquid enters from the liquid supply inlet 41, it first cools the stator 35 within the motor cooling channel and then flows into the deflection channel from the liquid supply outlet 43.

[0038] The steering channel includes a first channel 44, a first cavity 45, and a second channel 46 connected in sequence. The first cavity 45 is located between the second bearing 34 and the motor housing 31. The second channel 46 is axially located inside the second bearing 34. The first channel 44 is located on the outer diameter of the second bearing 34 and axially passes through the second bearing 34. The right end of the first channel 44 is connected to the left end of the liquid supply outlet 43. When the refrigerant liquid flows into the first channel 44 from the liquid supply outlet 43, the refrigerant liquid flows to the left side of the first cavity 45 and then turns to the right side of the cavity in the second channel 46. During this process, the refrigerant liquid cools the second bearing 34. After that, the refrigerant liquid flows into the discharge channel.

[0039] The discharge channel includes a rotor air gap 47, a third channel 48, a volute channel 49, and an intake channel 50 connected in sequence. The rotor air gap 47 is located between the stator 35 and the main shaft 32. The third channel 48 is axially located inside the first bearing 33. The volute channel 49 is located inside the first-stage volute 12. The intake channel 50 is located on the intake housing 11. The rotor air gap 47 is connected to the second channel 46. When the refrigerant liquid flows into the rotor air gap 47 from the second channel 46, it will cool the stator 35 a second time, which can better achieve the cooling effect. Then, the refrigerant liquid moves to the third channel 48 on the right side of the rotor air gap 47 and cools the first bearing 33. After the refrigerant liquid has finished cooling the motor assembly 3, it will flow out from the volute channel 49 and the intake channel 50. The intake channel 50 is connected to the first air inlet 21 of the compressor.

[0040] Liquid refrigerant flows through the suction port channel 50 and mixes with the low-temperature, low-pressure refrigerant gas in the first intake port 21 to form superheated vapor. This hot vapor then enters the gas circulation structure 2 through the first intake port 21, actively participating in the compressor's cycle. This enhances compressor performance, reduces the need for external connections, resulting in a more compact structure and lower equipment costs. The motor assembly 3 is cooled using liquid refrigerant, a clean and stain-free cooling medium. During cooling, the refrigerant undergoes a phase change and absorbs heat, resulting in excellent cooling performance. The refrigerant absorbs heat from the motor and becomes superheated vapor, providing a degree of superheat to the refrigerant gas drawn into the compressor, effectively preventing liquid carryover during compressor intake. Since the cooling channels involved in the cycle are fully integrated within the compressor, this design demonstrates high integration and significantly simplifies external piping and control systems.

[0041] like Figure 2As shown, the entire compressor's gas circulation structure 2 includes a first inlet 21, a suction assembly 22, an exhaust assembly 23, and a gas transmission channel 24. The suction assembly 22 includes a first impeller 221 and a first-stage diffuser 222. The first impeller 221 is disposed within the first inlet 21, with its larger surface area fixed to the right end of the main shaft 32 by bolts. The first-stage diffuser 222 is sandwiched between the first bearing 33 and the first impeller 221 and inserted into the outer diameter of the right end of the main shaft 32. The first volute is provided with a gas transmission channel 24. The first-stage diffuser 222 is connected to the first impeller 221 via a first-stage intake port 223, which is connected to one end of the gas transmission channel 24. When the refrigerant gas enters the first intake port 21, it will move to the left of the first impeller 221 under the rotation of the first impeller 221. After the gas passes through the impeller and the first-stage intake port 223, it will pass through the first-stage diffuser 222 and become a high-temperature and high-pressure refrigerant gas. At this time, the gas will be transmitted from the first-stage intake port 223 connected to the gas transmission channel 24 to the exhaust assembly 23.

[0042] The exhaust assembly 23 includes a second impeller 231 and a secondary diffuser 232. The second impeller 231 is disposed inside the secondary volute 13, and its larger surface area side is fixedly connected to the left end of the main shaft 32 by bolts. The secondary diffuser 232 is sandwiched between the second bearing 34 and the second impeller 231 and is inserted into the outer diameter of the left end of the main shaft 32. The second volute is also provided with a secondary air outlet 234 that passes through the secondary diffuser 232 and communicates with the second impeller 231. The secondary air outlet 234 communicates with the outer surface of the secondary volute 13. The secondary volute 13 is provided with a second air inlet 233, the second impeller 231 is disposed inside the second air inlet 233, and the other end of the gas transmission channel 24 is connected to the second air inlet 233. When the refrigerant gas is delivered from the first-stage intake port 223 to the second intake port 233, the second impeller 231 and the second-stage diffuser 232 will compress the gas again, making it a refrigerant gas with higher pressure and temperature. At this time, the gas will be discharged from the second-stage outlet port 234. The discharged high-temperature and high-pressure refrigerant gas is circulated through the refrigeration cycle principle and becomes a low-temperature and low-pressure gas that re-enters the first intake port 21. Thus, the compressor continuously provides power to drive the entire cycle.

[0043] like Figures 1 to 3As shown, an adjustable guide vane 25 is added inside the first air inlet 21. The adjustable guide vane 25 and the first impeller 221 are both installed inside the first-stage volute 12. The adjustable guide vane 25 is located at the right end of the first impeller 221 and can control the flow rate of gas entering the compressor. It occupies little space, uses worm gear transmission to transmit large torque, and is easy to control. The guide vane mechanism is also equipped with precise mechanical limit to ensure long-term reliable operation of the guide vane. The adjustable range of the adjustable guide vane 25 is 10~100%, which is a wide adjustment range and can significantly increase the compressor load adjustment range. The stepper motor lead wire is routed inside the compressor, avoiding the need for extra lead wires. The overall structure is simple.

[0044] like Figures 4 to 5 As shown, a primary sealing cover 224 is fitted onto the outer surface of the first impeller 221, and a secondary sealing cover 235 is fitted onto the outer surface of the second impeller 231. This ensures the integrity of both impellers and prevents them from being damaged. The first impeller 221 and the primary sealing cover 224 are housed within the primary volute 12. Since the primary volute 12 and the primary sealing cover 224 cannot fit perfectly together, a gap 27 of a certain size is provided between them. This gap 27 ranges from 0.1mm to 0.5mm. Without this gap 27, the equipment would not operate normally. Similarly, a gap 27 of the same size is provided between the second impeller 231 and the secondary sealing cover 235 and the secondary volute 13.

[0045] A sealing tooth structure 26 is provided on the outer curved surface of the primary sealing wheel cover 224, near the end of the first impeller 221 with a smaller surface area. A sealing tooth structure 26 is also provided on the outer curved surface of the secondary sealing wheel cover 235, near the end of the first impeller 221 with a smaller surface area. The sealing tooth structure 26 reduces gas leakage, thereby improving the overall efficiency of the machine. Sealing tooth structures 26 are also provided on the ends of the primary diffuser 222 and the secondary diffuser 232 at the points where they connect to the main shaft 32.

[0046] like Figure 1 As shown, a gas inlet 14 is provided on the compressor. The gas inlet 14 of the compressor is located on the secondary volute 13 and is connected to the second air inlet 233. By inputting the new gas into the compressor through the gas inlet 14, the circulation system can achieve the effect of gas replenishment and enthalpy increase, which greatly increases the system energy efficiency.

[0047] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A wide-width variable-frequency operation magnetic suspension centrifugal heat pump compressor, comprising a shell (1), a gas circulation structure (2) and a motor assembly (3), the gas circulation structure (2) and the motor assembly (3) are arranged inside the shell (1); the shell (1) comprises a suction shell (11), a primary volute (12), a motor shell (31) and a secondary volute (13), the secondary volute (13) and the primary volute (12) are fixedly connected at the left and right ends of the motor shell (31) respectively, and the suction shell (11) is fixedly arranged at the right end of the primary volute (12); the gas circulation structure (2) comprises a first air inlet (21) arranged on the suction shell (11) and communicating with the primary volute (12); wherein the motor assembly (3) comprises a main shaft (32), a first bearing (33), a second bearing (34) and a stator (35), the second bearing (34) and the first bearing (33) are arranged at the left and right ends of the motor shell (31) respectively, the main shaft (32) is arranged at the middle part of the first bearing (33) and the second bearing (34), and the stator (35) is arranged at the middle part of the main shaft (32); characterized in that a cooling channel is arranged in the compressor, the cooling channel comprises a motor cooling channel, a turning channel and a discharge channel, the motor cooling channel, the turning channel and the discharge channel are sequentially communicated; the motor cooling channel comprises a liquid supply inlet (41), a spiral groove (42) and a liquid supply outlet (43), the liquid supply inlet (41), the spiral groove (42) and the liquid supply outlet (43) are all arranged at the middle part of the motor shell (31), wherein the spiral groove (42) is arranged around the outer ring of the stator (35), the longitudinally arranged liquid supply inlet (41) and the transversely arranged liquid supply outlet (43) are respectively communicated with the two ends of the spiral groove (42); the turning channel comprises a first channel (44), a first cavity (45) and a second channel (46) which are sequentially connected, the first cavity (45) is arranged between the second bearing (34) and the motor shell (31), the second channel (46) is axially arranged in the second bearing (34), the first channel (44) is arranged on the outer diameter of the second bearing (34) and axially penetrates the second bearing (34), wherein the right end of the first channel (44) is communicated with the left end of the liquid supply outlet (43); the discharge channel comprises a rotor air gap (47), a third channel (48), a volute channel I (49) and a suction port channel (50) which are sequentially connected, the rotor air gap (47) is arranged between the stator (35) and the main shaft (32), the third channel (48) is axially arranged in the first bearing (33), the volute channel I (49) is arranged in the primary volute (12), and the suction port channel (50) is arranged on the suction shell (11), wherein the rotor air gap (47) is communicated with the second channel (46), and the suction port channel (50) is connected with the first air inlet (21) of the compressor. The refrigerant flows through the cooling channel and mixes with the low-temperature and low-pressure refrigerant gas in the first gas inlet (21) to form superheated steam, and the hot steam enters the compressor through the first gas inlet (21), so that the part of the refrigerant carries the heat after cooling the motor and actively participates in the circulation process of the compressor.

2. A magnetic levitation centrifugal heat pump compressor of the wide frequency variation operation type according to claim 1, characterized in that, The gas circulation structure (2) further comprises a gas suction assembly (22), a gas exhaust assembly (23) and a gas transmission channel (24). The gas suction assembly (22) comprises a first impeller (221) and a first diffuser (222), the first impeller (221) is arranged in the first gas inlet (21), the surface with a larger area is fixedly connected to the right end of the main shaft (32) by bolts, the first diffuser (222) is clamped between the first bearing (33) and the first impeller (221), and is inserted on the outer diameter of the right end of the main shaft (32); a first gas suction port (223) passing through the first diffuser (222) and communicating with the first impeller (221) is arranged on the first volute, and the first gas suction port (223) is communicated with one end of the gas transmission channel (24). The gas exhaust assembly (23) comprises a second impeller (231) and a second diffuser (232), the second impeller (231) is arranged in the second volute (13), the surface with a larger area is fixedly connected to the left end of the main shaft (32) by bolts, the second diffuser (232) is clamped between the second bearing (34) and the second impeller (231), and is inserted on the outer diameter of the left end of the main shaft (32), a second gas outlet (234) passing through the second diffuser (232) and communicating with the second impeller (231) is arranged on the second volute, and the second gas outlet (234) is communicated to the outer surface of the second volute (13). The second volute (13) is provided with a second gas inlet (233), the second impeller (231) is arranged in the second gas inlet (233), and the other end of the gas transmission channel (24) is connected to the second gas inlet (233).

3. A magnetic levitation centrifugal heat pump compressor of the wide frequency variation operation type according to claim 2, characterized in that, An adjustable guide vane (25) is further arranged in the first gas inlet (21), the adjustable guide vane (25) is fixedly installed in the first volute (12) and located at the right end of the first impeller (221).

4. A magnetic levitation centrifugal heat pump compressor of wide frequency variation operation according to claim 2, characterized in that, A first sealing wheel cover (224) is arranged on the outer surface of the first impeller (221), and a second sealing wheel cover (235) is arranged on the outer surface of the second impeller (231).

5. A magnetic levitation centrifugal heat pump compressor of the wide frequency variation operation type according to claim 4, characterized in that, The first diffuser (222) and the second diffuser (232) are both provided with sealing tooth structures (26) on the end of the main shaft (32), and the first sealing wheel cover (224) and the second sealing wheel cover (235) are also both provided with sealing tooth structures (26).

6. A magnetic levitation centrifugal heat pump compressor of the wide frequency variation operation type according to claim 5, characterized in that, A gap (27) is arranged between the first sealing wheel cover (224) and the first impeller (221), and a gap (27) is also arranged between the second sealing wheel cover (235) and the second impeller (231), and the size of the gap (27) is 0.1mm-0.5mm.

7. A magnetic levitation centrifugal heat pump compressor of wide frequency variation operation according to claim 2, characterized in that, The second volute (13) is provided with a gas supplement port (14) communicated with the second gas inlet (233).

8. A magnetic levitation centrifugal heat pump compressor of wide frequency variation operation according to claim 1, characterized in that, The left end of the secondary volute (13) is provided with a flange (15), the middle part of the flange (15) is aligned with the inlet of the second air inlet (233), and a gap (16) is arranged between the flange (15) and the second air inlet (233), the range of the gap (16) is 0.5mm-3mm.

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