CN113790176A

CN113790176A - Cooling device and steam compressor provided with same

Info

Publication number: CN113790176A
Application number: CN202111158731.5A
Authority: CN
Inventors: 叶文腾; 雷连冬; 钟瑞兴; 谢文浩
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2021-12-14

Abstract

The invention provides a cooling device and a steam compressor with the same, relates to the technical field of compressor cooling, and solves the technical problem that the existing steam compressor bearing and motor are poor in heat dissipation effect. The cooling device comprises a cooling pipeline and a cooling assembly, wherein the cooling pipeline comprises a first cooling pipe and a second cooling pipe, and a heat exchange section is arranged between the first cooling pipe and the second cooling pipe; the cooling assembly is arranged in the first cooling pipe and used for cooling a first medium in the first cooling pipe; and the first medium cools the second medium in the second cooling pipe in the heat exchange section. The inlet end of the first cooling pipe is communicated with a first-stage compression cavity of the compressor, high-temperature water vapor is introduced into the cooling device, and the cooling assembly cools the high-temperature water vapor; the cooled cold water cools the high-temperature hot air in the second cooling pipe in the heat exchange section, and formed cold air is introduced into the compressor, so that the bearing and/or the motor of the steam compressor are/is effectively cooled.

Description

Cooling device and steam compressor provided with same

Technical Field

The invention relates to the technical field of compressor cooling, in particular to a cooling device and a steam compressor with the same.

Background

With the rapid development of the refrigeration and air-conditioning industry, millions of tons of refrigerants are needed in the refrigeration field every year, and the refrigeration and air-conditioning industry faces serious challenges due to the damage to the ozone layer and the promotion effect on the greenhouse effect of chlorofluorocarbon artificial refrigerant. Water as a fourth generation refrigerant has the advantages of environmental protection (ODP is 0, GWP is less than 1), easily available raw materials, low cost, good safety, high stability, large latent heat of vaporization and the like, and can completely meet the environmental protection requirement so as to be applied to a vapor compressor system; however, the water vapor has low molecular weight, large specific volume and high adiabatic index, so that the water vapor system has the characteristics of small pressure difference, large pressure ratio, small unit volume refrigerating capacity, large volume flow, high exhaust temperature and the like, and higher requirements are also put forward for a compressor for the water vapor refrigeration system. The currently used steam compressors are mainly centrifugal steam compressors, screw steam compressors and roots-type steam compressors. Compared with a screw compressor and a Roots compressor, the centrifugal water vapor compressor has the advantages of large volume flow, good dynamic balance characteristic and small vibration, can provide an air source with higher pressure ratio, and can remarkably improve the power density and the overall performance of the electric pile. The centrifugal water vapor compressor adopting the dynamic pressure gas bearing has the advantages of small bearing friction loss, high rotating speed, good high-temperature stability, no need of lubricating oil and the like, and has very wide application prospect.

The centrifugal vapor compressor at present usually adopts foil dynamic pressure gas radial bearing, which belongs to one kind of sliding bearing, the working principle is dynamic pressure effect, the gas has certain viscosity, the gas is driven by the rotation of the permanent magnet rotor to trend from large gap to small gap cavity, along with the increase of the rotor speed, the gas distribution can reach a balance state, at the moment, the gas can form a layer of rigid gas film in the gap formed by the bearing and the rotor, thereby the rotor can be suspended in the air. Generally speaking, when a foil dynamical pressure gas radial bearing works, a high-pressure gas film is formed through a dynamical pressure effect, a wave foil structure of the bearing provides pressure for the gas film to support a rotor through deformation, when the rotor runs at a high speed, the whole rotor is in a suspended state under the action of the high-pressure gas film, friction heat consumption hardly exists in the case, however, when the rotor is in a low-speed state in the process of a take-off stage and the rotating speed is from low to high, transient slight friction exists between the rotor and a top foil, and the friction at the moment can generate certain heat to slightly raise the gas temperature, so that the stability of the formed gas film is influenced.

In addition, the centrifugal water vapor compressor is also provided with a most obvious high-temperature heating source, namely a motor, wherein the motor is used as power supply of the whole compressor and is communicated with a high-voltage power supply to run by excessive current to form a strong magnetic field so as to drive the permanent magnet rotor to rotate. The motor has large working current and large power, particularly when the motor is just started, the moment generated by the instant start of the rotor is large, and the current of the motor is very large, so that the resistance heat generated by the rotor is very large, and in addition, the motor works in a closed motor cylinder, the self-heat dissipation performance is poor, so that the temperature of a motor system is increased very fast, the temperature of the motor can reach more than 60 ℃ in a short time, and the motor can not continuously work to enter a standby state due to overheating often.

In summary, the heat dissipation problem of the existing centrifugal water vapor compressor bearing and motor needs to be solved urgently.

Disclosure of Invention

The invention aims to provide a cooling device and a steam compressor with the same, and at least solves the technical problem that in the prior art, the heat dissipation effect of a bearing and a motor of the steam compressor is poor. The technical effects that can be produced by the preferred technical scheme in the technical schemes provided by the invention are described in detail in the following.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a cooling device, comprising:

a cooling pipeline comprising a first cooling pipe and a second cooling pipe, wherein a heat exchange section is arranged between the first cooling pipe and the second cooling pipe;

a cooling unit that is provided in the first cooling pipe and cools a first medium in the first cooling pipe; and the first medium cools the second medium in the second cooling pipe in the heat exchange section.

Optionally, the cooling assembly is a first heat exchanger, a cooling liquid is disposed in the first heat exchanger, and the first cooling pipe penetrates through the first heat exchanger.

Optionally, at least a section of the first cooling tube located within the first heat exchanger is a bent tube.

Optionally, the cooling liquid is cold water.

Optionally, the first cooling tube comprises an inlet section and an intermediate section, the cooling assembly is located in the intermediate section, and the axes of the inlet section and the intermediate section are at an acute angle.

Optionally, a drive for the second medium is arranged in the second cooling pipe.

Optionally, the second cooling pipe comprises a second heat exchanger through which the first cooling pipe passes to exchange heat between the first medium and the second medium.

Optionally, the first cooling pipe further comprises a return branch, the first cooling pipe extends after passing through the second heat exchanger and is communicated to the first cooling pipe upstream of the cooling assembly to form the return branch.

Optionally, a check valve is disposed in the return branch.

The invention provides a vapor compressor, which comprises a primary volute, a motor cylinder, a motor stator, a dynamic pressure gas bearing, a secondary radial bearing support, a secondary diffuser and any one of the cooling devices; the inlet end of the first cooling pipe is communicated with the port of the first-stage volute or the volute, and the outlet end of the second cooling pipe is communicated with the inside of the compressor.

Optionally, an inlet end of the first cooling pipe is disposed on the first-stage volute, and an outlet end of the second cooling pipe is disposed on the motor cylinder.

Optionally, the secondary radial bearing support is symmetrically provided with air outlets.

Optionally, the second-stage diffuser is symmetrically provided with atomizing nozzles.

The invention provides a cooling device, which comprises a cooling pipeline and a cooling assembly, wherein the cooling pipeline comprises a first cooling pipe and a second cooling pipe, and a heat exchange section is arranged between the first cooling pipe and the second cooling pipe; the cooling assembly is arranged in the first cooling pipe and used for cooling a first medium in the first cooling pipe; and the first medium cools the second medium in the second cooling pipe in the heat exchange section. The inlet end of the first cooling pipe can be communicated with a first-stage compression cavity of the compressor, high-temperature water vapor (first medium) is introduced into the cooling device, and the high-temperature water vapor exchanges heat in the cooling assembly to form cold water; and high-temperature hot air (second medium) introduced by the second cooling pipe and the cold water form cold air after heat exchange in the heat exchange section, and the cold air enters the compressor from the outlet end of the second cooling pipe, so that the bearing and/or the motor of the steam compressor are/is effectively cooled.

After the cooling device is used by the steam compressor, a small part of heat generated by the dynamic pressure gas radial bearing in the starting stage is taken away in time by cold air, and the stability of a high-pressure gas film in the bearing is kept, so that the running reliability of the bearing is improved; and the cold wind transports the heat that the motor produced outside compressor system again, guarantees that the motor can long-term steady operation.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic cross-sectional view of a two-stage compression centrifugal steam compressor according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a cooling module according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a first cooling tube disposed in a first heat exchanger according to an embodiment of the present invention;

FIG. 4 is an enlarged schematic view of the atomizing head of FIG. 1 at part A;

FIG. 5 is a schematic diagram of the evaporation stage;

fig. 6 is a schematic view showing a connection relationship between the first cooling pipe and the second cooling pipe.

In figure 1, a first-stage impeller; 2. a first-stage volute; 3. an air outlet valve; 4. a first cooling pipe; 5. a cooling assembly; 51. cooling the housing; 6. a transfer valve; 7. a first-stage radial bearing support; 8. a hydrodynamic gas bearing; 9. a motor stator; 10. a motor cylinder; 11. a secondary radial bearing support; 12. a secondary diffuser; 13. a permanent magnet rotor; 14. an atomizing spray head; 15. an evaporator; 16. a one-way valve; 17. a blower.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

The present invention provides a cooling device comprising:

the cooling pipeline comprises a first cooling pipe 4 and a second cooling pipe, and a heat exchange section is arranged between the first cooling pipe 4 and the second cooling pipe;

a cooling unit that is provided in the first cooling pipe 4 and cools the first medium in the first cooling pipe 4; and the first medium cools the second medium in the second cooling pipe in the heat exchange section.

The inlet end of the first cooling pipe 4 can be communicated with a first-stage compression cavity of the compressor, high-temperature water vapor (first medium) is introduced into the cooling device, and the high-temperature water vapor exchanges heat in the cooling assembly to form cold water; and high-temperature hot air (second medium) introduced by the second cooling pipe and the cold water form cold air after heat exchange in the heat exchange section, and the cold air enters the compressor from the outlet end of the second cooling pipe, so that the bearing and/or the motor of the steam compressor are/is effectively cooled.

As an alternative embodiment, the cooling assembly 5 is a first heat exchanger, a cooling liquid is provided in the first heat exchanger, and the first cooling pipe 4 passes through the first heat exchanger. Simple structure and easy realization.

Specifically, as shown in fig. 2, the first heat exchanger includes a cooling housing 51, and the cooling housing 51 is provided with a cooling fluid inlet and a cooling fluid outlet; the first cooling pipe 4 penetrates the cooling case 51, and can exchange heat with the coolant that enters from the coolant inlet and fills the cavity of the cooling case 51.

Wherein, the cooling liquid is preferably cold water, and the cooling liquid is clean, environment-friendly, easy to obtain and low in cost.

As an alternative embodiment, at least a section of the first cooling pipe 4 located in the first heat exchanger is a bent pipe, and the shape of the bent pipe is not limited as long as the length of the first cooling pipe 4 in the first heat exchanger can be increased. As shown in fig. 3, the spiral tube is adopted in the embodiment, so that the length of the heat exchange section can be effectively increased, and the heat exchange efficiency is improved. Compared with other bent pipes, the spiral pipe can effectively utilize space and increase the length of the heat exchange section to the maximum extent.

As an alternative embodiment, as shown in fig. 1 and 6, the first cooling pipe 4 includes an introduction section and an intermediate section, the cooling assembly 5 is located in the intermediate section, and the axes of the introduction section and the intermediate section are at an acute angle. The vertically disposed lead-in section is at an acute angle α to the axis of the intermediate section, such that the intermediate section is inclined to facilitate the flow of the condensed cold water by gravity to the evaporator 15.

As an alternative embodiment, a drive for the second medium is arranged in the second cooling pipe. In this embodiment, the second medium is air, and a blower 17 is provided downstream of the second heat exchanger in the second cooling pipe to supply power to the cool air.

As an alternative embodiment, the second cooling tube comprises an evaporator 15 as a second heat exchanger through which the first cooling tube 4 passes for heat exchange of the first medium with the second medium, see fig. 6.

As an alternative embodiment, as shown in fig. 1, 5 and 6, the first cooling pipe 4 further comprises a return branch, and the first cooling pipe 4 extends after passing through the second heat exchanger and is communicated to the first cooling pipe 4 upstream of the cooling assembly 5 to form the return branch. The reflux branch is convenient for mixing and recycling high-temperature water vapor formed by evaporation after heat exchange in the evaporator 15 and high-temperature water vapor introduced from the inlet end of the first cooling pipe 4.

Specifically, a check valve 16 is provided in the return branch to prevent the backflow of the high-temperature water vapor.

The invention provides a steam compressor, which comprises a primary impeller 1, a primary volute 2, a primary radial bearing support 7, a motor cylinder 10, a motor stator 9, a dynamic pressure gas bearing 8, a permanent magnet rotor 13, a secondary radial bearing support 11, a secondary diffuser 12 and any one of the cooling devices; the inlet end of the first cooling pipe 4 is communicated with the port of the first-stage volute 2 or the inside of the volute, and the outlet end of the second cooling pipe is communicated with the inside of the compressor.

After the steam compressor uses the cooling device, cold air takes away a small part of heat generated by the dynamic pressure gas radial bearing in a starting stage in time, and the stability of a high-pressure gas film in the bearing is kept, so that the running reliability of the bearing is improved; and the cold wind transports the heat that the motor produced outside compressor system again, guarantees that the motor can long-term steady operation.

As shown in fig. 1, the embodiment of the present invention provides a two-stage compression centrifugal water vapor compressor, which mainly comprises: the device comprises a primary impeller 1, a primary volute 2, an air outlet valve 3, a cooling pipeline, a cooling motor 5, a switching valve 6, a radial bearing support 7, a radial dynamic pressure air suspension bearing 8, a motor stator 9, a motor cylinder 10, a secondary radial bearing support 11, a secondary diffuser 12, a permanent magnet rotor 13 and an atomizing nozzle 14. The inlet end of the first cooling pipe 4 is arranged on the first-stage volute 2, and the outlet end of the second cooling pipe is arranged on the motor cylinder 10. Wherein:

the primary impeller 1 is formed by processing a casting and is a key part of the compressor, and is mainly used for acting and accelerating water vapor and has great influence on the energy efficiency of the compressor.

The first-stage volute 2 is an irregular casting, the structure of the first-stage volute is complex, the first-stage volute is a guide mechanism for the flow of water vapor pressurized by the first-stage diffuser, and the noise performance of the compressor is directly influenced by the structural design and the processing quality of the first-stage volute.

The air outlet valve 3 is a purchased part, generally consists of brass and plastic, is connected with the volute through threads, is connected with the first cooling pipe 4, and is mainly used for guiding part of vapor after primary compression in the compressor into the cooling component 5 to cool the motor and the bearing of the compressor.

The first cooling pipe 4 mainly has a flow guiding and air conveying function, wherein the portion arranged in the cooling assembly 5 is of a spiral structure, as shown in fig. 3, and the spiral structure can increase the cooling time of the water vapor so as to improve the cooling effect. Because the centrifugal compressor impeller is very sensitive to liquid drops, in order to prevent the cooled water vapor from being partially liquefied and flowing back to the first-stage volute 2, the included angle between the axis of the middle section (including the spiral pipe) and the vertical steam section is an acute angle, so that the liquefied water drops can only flow forwards all the time under the action of gravity, and the cooling efficiency is improved.

The schematic structure of the cooling assembly 5 is shown in fig. 2, and the cooling assembly is composed of a cooling container (cooling shell 51) and a cooling liquid loop, the cooling shell 51 and the spiral gas pipe are sealed and bonded by waterproof glue, a cold water inlet is connected with an external cold water source, cold water is filled into the cooling shell 51 from top to bottom, the heat of water vapor can be taken away quickly, and the cooling effect of the water vapor is guaranteed. The switching valve 6 is a purchased part and mainly connects the cooling pipelines, and is generally made of plastic.

The first-stage radial bearing support 7 and the second-stage radial bearing support 11 are both rotary and hollow castings and are symmetrically distributed on two sides of the motor cylinder 10. The first-stage radial bearing support 7 is connected with the motor cylinder 10 and the dynamic pressure gas bearing 8 and provides support for the dynamic pressure gas bearing 8; similarly, the secondary radial bearing 11 provides support for the secondary hydrodynamic gas.

The dynamic pressure gas bearing 8 is a foil dynamic pressure gas radial bearing, symmetrically distributed at two ends of the motor cylinder 10, and is in interference connection with the dynamic pressure bearing support 7 through a bearing shell, in the invention, the dynamic pressure gas bearing 8 is a cooled object, as shown in fig. 1, the dynamic pressure gas bearing 8 and the bearing support are in interference fit, heat generated by the dynamic pressure gas bearing can be quickly transmitted to the bearing support, and after cold air is input into the compressor by the air blower 17, the cold air quickly flows and flees through the surface of the bearing support, and the heat is quickly taken away, so that the effect of cooling the bearing is achieved.

The motor stator 9 is composed of a motor winding, is embedded with the motor cylinder 10 through a thermal sleeve, and is connected with a high-voltage power supply in a motor cavity to generate a strong magnetic field to act on the motor rotor 13 so as to rotate at a high speed. The motor stator 9 is formed by hot sleeving of three parts, wherein one part is permanent magnet steel, has strong magnetism, is a high-precision part and is used for driving the impeller to rotate at a high speed under the action of the motor stator. The motor stator 9 is the cooling object of the patented technology, and the heat generation phenomenon is very rapid due to the high-voltage current flowing in the motor stator 9, and the motor stator is the most main heat generation source in a compressor. As shown in fig. 1, a spiral ventilation channel is distributed on the cylindrical surface of the inner ring of the motor cylinder 10 matched with the motor stator 9, and cold air is input into the primary-side compressor cavity by the air blower 17 and then enters the spiral channel on the inner ring of the motor cylinder 10, so that the cold air rapidly flows around the surface of the motor stator 9, and the heat generated by the motor is taken away and then enters the secondary compressor cavity. The spiral structure flow channel not only increases the contact area of the cooled steam fully and the motor stator 9, but also increases the cooling time and improves the cooling effect.

The motor cylinder 10 is a casting with an irregular shape and a hollow part, is a main supporting component of the compressor, and provides a supporting and positioning function for a volute, a diffuser, a bearing support, a motor stator and the like. The inner wall of the cooling device is provided with a spiral cooling channel for cooling the motor stator. The secondary radial bearing support 11 is a revolving body and a hollow casting and mainly provides support for a secondary radial bearing. Two air outlets which are distributed up and down symmetrically are arranged on the motor stator and are shown in figure 1, and the two air outlets are mainly used for discharging and guiding high-temperature hot air which is discharged from the motor stator 9 into the secondary diffuser in time. The second-stage diffuser 12 is a revolving body processing part, and mainly performs secondary compression on the water vapor after the first-stage compression to convert the kinetic energy of the water vapor into pressure energy and internal energy, so as to further improve the temperature and the pressure of the water vapor. The two atomizing nozzles 14 are symmetrically arranged on the second-stage diffuser 12, so that high-temperature hot air heated due to heat absorption in the compressor can be recycled in the second-stage compression link of the compressor and mixed with water vapor for continuous compression.

The atomizing nozzle 14 is a purchased part, and has a structure shown in fig. 4, and cold air after work can smoothly enter a secondary diffuser link under the action of pressure through the pressure difference between two sides of the secondary diffuser 12, and can prevent water vapor in the secondary diffuser 12 from backflushing the inside of the compressor. The atomizing nozzles 14 are mounted on two symmetrical sides of the second-stage diffuser 12 in a threaded connection manner. The permanent magnet rotor 13 is formed by hot sleeving three parts, is a solid part, and the embedded part is permanent magnet steel, so that the permanent magnet rotor 13 can run at a high speed under the action of a strong magnetic field generated by the motor stator 10, the rotating speed can reach tens of thousands of revolutions per minute, and a dynamic balance test is generally carried out before the permanent magnet rotor is used to ensure the running stability of the permanent magnet rotor.

Under the condition that a pipeline is arranged outside the compressor, water vapor compressed by the first stage of the compressor is introduced into the external cooling component 5 and then is cooled by cold air generated by the evaporator 15, and the water vapor which absorbs heat and is gasified again returns to the initial gas conveying pipe through the one-way valve 16 for recycling. The method comprises the following steps: the pressurizing of the first-stage diffuser → the leading out of the first cooling pipe 4 → the cooling of the cooling component 5 → the gasification of the evaporator 15 to generate cold air → the air blower 17 to input the cold air into the compressor → the cold air passes through the dynamic pressure gas bearing 8 → the atomizing nozzle 14 to be led out → the pressing in of the second-stage diffuser 12 to be mixed with the water vapor to continue the secondary compression, so that the water vapor and the cold air can be reused while the motor and the bearing are cooled, and the purposes of energy conservation, emission reduction and environmental protection are achieved.

In order to avoid the compressor to shut down because of motor overheat in the process of working and running, the patent designs a motor stator cooling technology applied to a centrifugal water vapor compressor so as to improve the sustainability and stability of the work of the compressor and achieve the purpose of improving the production efficiency.

Because the working medium of the centrifugal water vapor compressor is water vapor, the first cooling pipe 4 is arranged outside the compressor to directly utilize the water vapor of the compressor, and the second cooling pipe introduces high-pressure gas through primary exhaust to cool and then carries out energy transfer through the evaporator 15 and hot air generated by industrial waste heat, so that the industrial high-temperature hot air is cooled into cold air which is used as a source of cooling air (cold air).

The air blower 17 is used for guiding cold air into the compressor, the cold air firstly flows through the first-stage radial bearing shell to take away heat of the bearing, and then the cold air is quickly sent out of the compressor through the spiral cooling flow channel on the cylinder to take away high-temperature heat generated by the motor stator. The cold air absorbs heat and is heated up again to become high-temperature hot air, and then enters a secondary compression link through an atomizing nozzle to be mixed with high-temperature steam for continuous secondary compression.

The high-temperature hot air source can utilize waste heat in industrial production, so that the compressor is more environment-friendly, and the energy utilization rate is improved.

In the description of the invention, it is to be noted that "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing and simplifying the description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus are not to be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present invention can be understood as appropriate to those of ordinary skill in the art.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A cooling apparatus, comprising:

2. The cooling device of claim 1, wherein the cooling assembly is a first heat exchanger having a cooling fluid disposed therein, and the first cooling tube passes through the first heat exchanger.

3. A cooling arrangement according to claim 2, characterised in that at least a section of the first cooling tube located within the first heat exchanger is a bent tube.

4. The cooling apparatus of claim 2, wherein the cooling fluid is cold water.

5. The cooling apparatus of claim 1, wherein the first cooling tube comprises an induction section and an intermediate section, the cooling assembly is located in the intermediate section, and an axis of the induction section and the intermediate section is at an acute angle.

6. A cooling arrangement according to claim 1, characterised in that a drive for the second medium is arranged in the second cooling pipe.

7. A cooling arrangement according to any one of claims 1-6, characterized in that the second cooling pipe comprises a second heat exchanger through which the first cooling pipe passes for heat exchange of the first medium with the second medium.

8. The cooling arrangement as set forth in claim 7 wherein said first cooling tube further includes a return branch, said first cooling tube extending through said second heat exchanger and communicating to said first cooling tube upstream of said cooling assembly to form said return branch.

9. A cooling arrangement according to claim 8, characterised in that a one-way valve is arranged in the return branch.

10. A vapor compressor comprising a primary volute, a motor cylinder, a motor stator, a dynamic pressure gas bearing, a secondary radial bearing support, a secondary diffuser and the cooling device of any one of claims 1 to 9; the inlet end of the first cooling pipe is communicated with the port of the first-stage volute or the volute, and the outlet end of the second cooling pipe is communicated with the inside of the compressor.

11. The vapor compressor of claim 10, wherein an inlet end of the first cooling tube is disposed on the one-stage volute and an outlet end of the second cooling tube is disposed on the motor cylinder.

12. The vapor compressor as recited in claim 10 or 11, wherein the secondary radial bearing support is symmetrically provided with air outlets.

13. The vapor compressor as recited in claim 12, wherein the secondary diffuser is symmetrically provided with atomizing spray heads.