A cooling device and a steam compressor provided with the same

Abstract

The present invention provides a cooling device and a steam compressor provided with the same, relating to the technical field of compressor cooling, and solving the technical problem that the heat dissipation effect of the bearings and motors of existing water vapor compressors is relatively poor. The cooling device includes a cooling pipeline and a cooling component. The cooling pipeline includes a first cooling pipe and a second cooling pipe, and there is a heat exchange section between the first cooling pipe and the second cooling pipe. The cooling component is arranged in the first cooling pipe to cool a first medium in the first cooling pipe, and the first medium cools a second medium in the second cooling pipe at the heat exchange section. The inlet end of the first cooling pipe is communicated with the first-stage compression chamber of the compressor to introduce high-temperature water vapor into the cooling device, and the cooling component cools the high-temperature water vapor. The cooled cold water cools the high-temperature hot air in the second cooling pipe at the heat exchange section, and the formed cold air is introduced into the interior of the compressor, thereby effectively cooling the bearings and / or motors of the steam compressor.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor cooling, and in particular to a cooling device and a steam compressor provided with the same. Background Art

[0002] With the rapid development of the refrigeration and air-conditioning industry, the annual demand for refrigerants in the refrigeration field reaches up to millions of tons. However, chlorofluorocarbon-based synthetic refrigerants pose a serious challenge to the refrigeration and air-conditioning industry due to their damage to the ozone layer and promotion of the greenhouse effect. As the fourth-generation refrigerant, water has many advantages such as being green and environmentally friendly (ODP = 0, GWP < 1), easy availability of raw materials, low cost, good safety, high stability, and large latent heat of vaporization, and can fully meet the environmental protection requirements and thus be applied in the vapor compressor system. However, the low molecular weight, large specific volume, and high adiabatic index of water vapor also determine that the water vapor system has characteristics such as small pressure difference, large pressure ratio, small refrigerating capacity per unit volume, large volume flow rate, and high exhaust temperature, which also pose higher requirements for the compressors used in the water vapor refrigeration system. Currently, the water vapor compressors in use mainly include centrifugal water vapor compressors, screw water vapor compressors, and Roots water vapor compressors. Compared with screw compressors and Roots compressors, centrifugal water vapor compressors have the advantages of large volume flow rate, good dynamic balance characteristics, and small vibration, can provide a gas source with a higher pressure ratio, and can significantly improve the power density and overall performance of the stack. And the centrifugal water vapor compressor using a hydrodynamic gas bearing has a series of advantages such as small bearing friction loss, high rotational speed, good high-temperature stability, and no need for lubricating oil, and has a very broad application prospect.

[0003] Currently, a foil hydrodynamic gas radial bearing is often used in centrifugal steam compressors. It belongs to a type of sliding bearing, and its working principle is the hydrodynamic effect. The gas has a certain viscosity. The rotation of the permanent magnet rotor drives the gas from the large-gap cavity to the small-gap cavity. As the rotor speed increases, the gas distribution will reach an equilibrium state. At this time, the gas will form a rigid gas film in the gap formed between the bearing and the rotor, so that the rotor can be suspended. Generally speaking, when the foil hydrodynamic gas radial bearing works, a high-pressure gas film is formed through the hydrodynamic effect, and the wave foil structure of the bearing deforms to provide pressure support for the gas film to support the rotor. When the rotor runs at a high speed, the entire rotor is in a suspended state under the action of the high-pressure gas film, and there is almost no frictional heat loss in this case. However, during the take-off stage, in the low-speed state when the speed increases from low to high, there will be a short-term slight friction between the rotor and the top foil, and the friction at this time will generate a certain amount of heat, causing the gas temperature to rise slightly, affecting the stability of the gas film formation.

[0004] In addition, the centrifugal steam compressor has another most significant high-temperature heat source - the motor. As the power supply of the entire compressor, the motor is connected to the high-voltage power supply and operates with a large current to form a strong magnetic field, thereby driving the permanent magnet rotor to rotate. Due to its large working current and high power, especially when the motor just starts, the torque generated by the instantaneous start of the rotor is very large, and the motor current at this time is very large. Therefore, the resistance heat generated is extremely huge. Coupled with its operation in a relatively enclosed motor cylinder body and poor self-cooling performance, the temperature of the motor system rises extremely fast. In a short period of time, the temperature of the motor can reach above 60°C. In many cases, the motor often cannot continue to work due to overheating and enters the standby state.

[0005] In summary, the heat dissipation problems of the bearings and motors of existing centrifugal steam compressors need to be solved urgently. Summary of the Invention

[0006] The purpose of the present invention is to provide a cooling device and a steam compressor provided with the same, which can at least solve the technical problem of poor heat dissipation effect of the bearings and motors of the steam compressor in the prior art. The many technical effects that can be produced by the preferred technical solutions provided by the present invention are described in detail below.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A cooling device provided by the present invention includes:

[0009] A cooling pipeline, which includes a first cooling pipe and a second cooling pipe, and there is a heat exchange section between the first cooling pipe and the second cooling pipe;

[0010] A cooling component, which is arranged in the first cooling pipe to cool the 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.

[0011] Optionally, the cooling component is a first heat exchanger, a coolant is arranged in the first heat exchanger, and the first cooling pipe passes through the first heat exchanger.

[0012] Optionally, at least part of the section of the first cooling pipe located in the first heat exchanger is a bent pipe.

[0013] Optionally, the coolant is cold water.

[0014] Optionally, the first cooling pipe includes an introduction section and an intermediate section, the cooling component is located in the intermediate section, and the axes of the introduction section and the intermediate section form an acute angle.

[0015] Optionally, a driving device for the second medium is arranged in the second cooling pipe.

[0016] Optionally, the second cooling pipe includes a second heat exchanger, and the first cooling pipe passes through the second heat exchanger to exchange heat between the first medium and the second medium.

[0017] Optionally, the first cooling pipe further includes a reflux branch. After passing through the second heat exchanger, the first cooling pipe extends and communicates with the first cooling pipe upstream of the cooling assembly to form the reflux branch.

[0018] Optionally, a check valve is provided in the reflux branch.

[0019] A steam compressor provided by the present invention includes a first-stage volute, a motor cylinder, a motor stator, a hydrodynamic gas bearing, a second-stage radial bearing support, a second-stage diffuser, and the cooling device described in any one of the above; an inlet end of the first cooling pipe communicates with a port of the first-stage volute or inside the volute, and an outlet end of the second cooling pipe communicates with the inside of the compressor.

[0020] Optionally, the inlet end of the first cooling pipe is arranged on the first-stage volute, and the outlet end of the second cooling pipe is arranged on the motor cylinder.

[0021] Optionally, air outlet ports are symmetrically formed on the second-stage radial bearing support.

[0022] Optionally, atomizing nozzles are symmetrically arranged on the second-stage diffuser.

[0023] A cooling device provided by the present invention includes a cooling pipeline and a cooling assembly. The cooling pipeline includes a first cooling pipe and a second cooling pipe, and there is a heat exchange section between the first cooling pipe and the second cooling pipe; the cooling assembly is arranged in the first cooling pipe to cool a first medium in the first cooling pipe; and the first medium cools a second medium in the second cooling pipe in the heat exchange section. The inlet end of the first cooling pipe can communicate with a first-stage compression chamber of a compressor to introduce high-temperature water vapor (the first medium) into the cooling device, and the high-temperature water vapor exchanges heat in the cooling assembly to form cold water; and the high-temperature hot air (the second medium) introduced by the second cooling pipe exchanges heat with the above-mentioned cold water in the heat exchange section to form cold air and enters the inside of the compressor from the outlet end of the second cooling pipe, thereby effectively cooling the bearings and / or the motor of the steam compressor.

[0024] After the steam compressor uses this cooling device, the cold air timely takes away a small part of the heat generated by the hydrodynamic gas radial bearing during the starting stage, maintaining the stability of the high-pressure gas film inside the bearing, thereby improving the reliability of the bearing operation; and the cold air transports the heat generated by the motor outside the compressor system, ensuring that the motor can operate stably for a long time. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 It is a schematic cross-sectional structure diagram of a two-stage compression centrifugal steam compressor provided by the specific embodiment of the present invention;

[0027] Figure 2 It is a schematic structure diagram of a cooling assembly provided by the specific embodiment of the present invention;

[0028] Figure 3 It is a schematic structure diagram of a first cooling pipe located in a first heat exchanger provided by the specific embodiment of the present invention;

[0029] Figure 4 is Figure 1 an enlarged structural diagram of the atomizing nozzle in part A in

[0030] Figure 5 It is a working principle diagram of the evaporation link;

[0031] Figure 6 It is a schematic connection diagram of the first cooling pipe and the second cooling pipe.

[0032] In the figure, 1 is the first-stage impeller; 2 is the first-stage volute; 3 is the outlet valve; 4 is the first cooling pipe; 5 is the cooling assembly; 51 is the cooling housing; 6 is the transfer valve; 7 is the first-stage radial bearing support; 8 is the hydrodynamic gas bearing; 9 is the motor stator; 10 is the motor cylinder; 11 is the second-stage radial bearing support; 12 is the second-stage diffuser; 13 is the permanent magnet rotor; 14 is the atomizing nozzle; 15 is the evaporator; 16 is the check valve; 17 is the blower. Specific Embodiments

[0033] To make the purpose, technical solutions and advantages of the present invention clearer, the following will describe the technical solutions of the present invention in detail. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0034] The present invention provides a cooling device, including:

[0035] A cooling pipeline, which includes a first cooling pipe 4 and a second cooling pipe, and there is a heat exchange section between the first cooling pipe 4 and the second cooling pipe;

[0036] A cooling assembly is disposed in the first cooling pipe 4 to cool 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.

[0037] The inlet end of the first cooling pipe 4 can be connected to the first-stage compression chamber of the compressor to introduce high-temperature water vapor (the first medium) into the cooling device. The high-temperature water vapor exchanges heat in the cooling assembly to form cold water; and the high-temperature hot air (the second medium) introduced by the second cooling pipe exchanges heat with the above-mentioned cold water in the heat exchange section to form cold air and enters the compressor interior from the outlet end of the second cooling pipe, thereby effectively cooling the bearings and / or the motor of the steam compressor.

[0038] As an alternative embodiment, the cooling assembly 5 is a first heat exchanger. A coolant is provided inside the first heat exchanger, and the first cooling pipe 4 passes through the first heat exchanger. The structure is simple and easy to implement.

[0039] Specifically, as Figure 2 shown, the first heat exchanger includes a cooling housing 51. A coolant inlet and a coolant outlet are provided on the cooling housing 51; the first cooling pipe 4 penetrates through the cooling housing 51 and can exchange heat with the coolant that enters from the coolant inlet and fills the chamber of the cooling housing 51.

[0040] Among them, the coolant is preferably cold water, which is clean, environmentally friendly, easy to obtain, and low in cost.

[0041] As an alternative embodiment, at least a part of the section of the first cooling pipe 4 located inside the first heat exchanger is a bent pipe. The shape of the bent pipe is not limited as long as it can increase the length of the first cooling pipe 4 inside the first heat exchanger. As Figure 3 shown, a spiral pipe is adopted in this embodiment, which can effectively increase the length of the heat exchange section and improve the heat exchange efficiency. Compared with other forms of bent pipes, the spiral pipe can effectively utilize the space and maximize the increase in the length of the heat exchange section.

[0042] As an alternative embodiment, as Figure 1 and Figure 6 shown, the first cooling pipe 4 includes an inlet section and an intermediate section. The cooling assembly 5 is located in the intermediate section, and the axes of the inlet section and the intermediate section form an acute angle. The vertically arranged inlet section and the axis of the intermediate section form an acute angle α, so that the intermediate section is inclined, which is convenient for the condensed cold water to flow towards the evaporator 15 by gravity.

[0043] As an alternative embodiment, a driving device for the second medium is provided 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 provide power for the cold air.

[0044] As an optional embodiment, the second cooling pipe includes an evaporator 15 as a second heat exchanger, and the first cooling pipe 4 passes through the second heat exchanger to exchange heat between the first medium and the second medium, see Figure 6 .

[0045] As an optional implementation, Figure 1 , Figure 5 and Figure 6 As shown, the first cooling pipe 4 also includes a reflux branch, which extends after passing through the second heat exchanger and is connected to the first cooling pipe 4 upstream of the cooling assembly 5 to form a reflux branch. The reflux branch facilitates the mixing and reuse of the high-temperature water vapor evaporated after heat exchange in the evaporator 15 and the high-temperature water vapor introduced at the inlet end of the first cooling pipe 4.

[0046] Specifically, a one-way valve 16 is provided in the reflux branch to prevent the high-temperature water vapor from flowing back.

[0047] A steam compressor provided by the present invention comprises a first-stage impeller 1, a first-stage volute 2, a first-stage radial bearing support 7, a motor barrel 10, a motor stator 9, a dynamic pressure gas bearing 8, a permanent magnet rotor 13, a second-stage radial bearing support 11, a second-stage diffuser 12 and any cooling device thereof; the inlet end of the first cooling pipe 4 is connected to the port of the first-stage volute 2 or the inside of the volute, and the outlet end of the second cooling pipe is connected to the interior of the compressor.

[0048] After the steam compressor uses the above cooling device, the cold air will promptly take away a small part of the heat generated by the dynamic pressure gas radial bearing during the startup phase, maintaining the stability of the high-pressure gas film in the bearing, thereby improving the reliability of the bearing operation; and the cold air will transport the heat generated by the motor to the outside of the compressor system, ensuring that the motor can operate stably for a long time.

[0049] like Figure 1 As shown, the specific embodiment of the present invention provides a two-stage compression centrifugal water vapor compressor, which mainly includes: a first-stage impeller 1, a first-stage volute 2, an 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 barrel 10, a second-stage radial bearing support 11, a second-stage 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 barrel 10. Among them:

[0050] The first-stage impeller 1 is made of castings and is a key part of the compressor. It is mainly used to speed up the work of water vapor and has a great influence on the energy efficiency of the compressor.

[0051] The first-stage volute 2 is a casting with an irregular shape and a relatively complex structure. It is a guiding mechanism for the flow of water vapor pressurized by the first-stage diffuser. The quality of its structural design and processing will directly affect the noise performance of the compressor.

[0052] The outlet valve 3 is a purchased part, generally composed of brass and plastic, and is connected to the volute by a thread. The outlet is connected to the first cooling pipe 4. Its main function is to introduce some of the water vapor compressed at the first stage in the compressor into the cooling assembly 5 for cooling, and then cool the motor and bearings of the compressor.

[0053] The first cooling pipe 4 mainly functions as a diversion and gas transmission. The part arranged in the cooling assembly 5 is of a spiral structure. As Figure 3 shown, the spiral pipe can increase the cooling time of the water vapor, thereby improving the cooling effect. Since the impeller of the centrifugal compressor is very sensitive to liquid droplets, in order to prevent some of the cooled water vapor from liquefying and flowing back to the first-stage volute 2, the 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 droplets can only flow forward under the action of gravity, improving the cooling efficiency.

[0054] The cooling assembly 5, its schematic structure is as Figure 2 shown, is composed of a cooling container (cooling housing 51) and a coolant circuit. The cooling housing 51 and the spiral gas transmission pipe are sealed and bonded with waterproof glue. The cold water inlet is connected to an external cold water source. Cold water is poured into the cooling housing 51 from top to bottom, which can quickly take away the heat of the water vapor and ensure the cooling effect of the water vapor. The transfer valve 6 is a purchased part, mainly connecting each section of the cooling pipeline, and is generally made of plastic.

[0055] Both the first-stage radial bearing support 7 and the second-stage radial bearing support 11 are rotary and hollow castings, and are symmetrically distributed on both sides of the motor cylinder 10. Among them, the first-stage radial bearing support 7 connects the motor cylinder 10 and the hydrodynamic gas bearing 8, providing support for the hydrodynamic gas bearing 8; similarly, the second-stage radial bearing 11 provides support for the second-stage hydrodynamic gas.

[0056] The hydrodynamic gas bearing 8 is a foil hydrodynamic gas radial bearing, symmetrically distributed at both ends of the motor cylinder 10, and is connected with an interference fit through the bearing housing and the hydrodynamic bearing support 7. In the present invention, the hydrodynamic gas bearing 8 is the object to be cooled. As Figure 1 shown, the hydrodynamic gas bearing 8 and the bearing support are in an interference fit. The heat generated by the hydrodynamic gas bearing will be quickly transferred to the bearing support. After the blower 17 inputs cold air into the compressor, it quickly flows through the surface of the bearing support, quickly taking away its heat, thereby achieving the effect of cooling the bearing.

[0057] The motor stator 9 is composed of motor windings and is fitted together with the motor cylinder 10 by shrink fitting. By connecting to a high-voltage power supply, a strong magnetic field is generated in the motor cavity, acting on the motor rotor 13 to make it rotate at high speed. The motor stator 9 is formed by shrink fitting three parts, one of which is a permanent magnet steel with strong magnetism and is a high-precision part. Its function is to drive the impeller to rotate at high speed under the action of the motor stator. The motor stator 9 is the cooling object of this patented technology. Because high-voltage current passes through the motor stator 9, its heat generation phenomenon is very rapid, and it is the main heat source in a compressor. As Figure 1 shown, a spiral air flow channel is distributed on the cylindrical surface of the inner ring of the motor cylinder 10 that cooperates with the motor stator 9. After the blower 17 inputs cold air into the primary-side compressor cavity, it will enter the spiral flow channel on the inner ring of the motor cylinder 10, thus flowing rapidly around the surface of the motor stator 9, taking away the heat generated by the motor and then entering the secondary compressor cavity. The spiral-structured flow channel not only increases the contact area between the cooling water vapor and the motor stator 9, but also increases its cooling time and improves the cooling effect.

[0058] The motor cylinder 10 is an irregularly shaped casting and a hollow part, which is the main supporting component of the compressor and provides support and positioning for the volute, diffuser, bearing support, motor stator, etc. A spiral cooling channel is provided on its inner wall for cooling the motor stator. The secondary radial bearing support 11 is a rotating body and a hollow casting, mainly providing support for the secondary radial bearing. Two symmetrically distributed air outlets are provided on it as Figure 1 shown. The main function of these two air outlets is to timely discharge the high-temperature hot air coming out of the motor stator 9 and introduce it into the secondary diffuser. The secondary diffuser 12 is a rotating body machining part, mainly used to perform secondary compression on the water vapor compressed in the primary stage, converting the kinetic energy of the water vapor into pressure energy and internal energy, and further increasing the temperature and pressure of the water vapor. Two atomizing nozzles 14 are provided symmetrically up and down on the secondary diffuser 12, which can recover the high-temperature hot air heated by absorbing heat inside the compressor and mix it with the water vapor in the secondary compression link of the compressor to continue compression.

[0059] The atomizing nozzle 14 is a purchased part, and its structure is as Figure 4 shown. Through the pressure difference on both sides of the secondary diffuser 12, the cold air after work can smoothly enter the secondary compression link under the action of pressure, and can prevent the water vapor in the secondary diffuser 12 from backflushing into the compressor interior. The atomizing nozzle 14 is installed on the symmetric two sides of the secondary diffuser 12 by means of threaded connection. The permanent magnet rotor 13 is formed by shrink fitting three parts and is a solid part. The embedded part in it is a permanent magnet steel. Therefore, the permanent magnet rotor 13 can rotate at high speed under the action of the strong magnetic field generated by the motor stator 10, and the rotation speed can reach tens of thousands of revolutions per minute. Generally, a dynamic balance test will be carried out before its use to ensure its running stability.

[0060] In the case of a pipeline outside the compressor, the water vapor after the first-stage compression of the compressor is introduced into the external cooling component 5 and then the cold air is generated through the evaporator 15 to cool the compressor. The water vapor that absorbs heat and vaporizes again returns to the starting gas pipeline through the one-way valve 16 for repeated use. The general process is: the first-stage diffuser pressurizes → the first cooling pipe 4 is led out → the cooling component 5 is cooled → the evaporator 15 vaporizes to generate cold air → the blower 17 inputs the cold air into the compressor → the cold air passes through the dynamic pressure gas bearing 8 → the atomizing nozzle 14 is led out → it is pressed into the second-stage diffuser 12 to mix with the water vapor and continue the second-stage compression. While cooling the motor and the bearing, the water vapor and the cold air can be used in multiple ways, achieving the purpose of energy saving, emission reduction and green environmental protection.

[0061] In order to prevent the compressor from shutting down due to motor overheating during operation, this patent designs a motor stator cooling technology applied to a centrifugal steam compressor to improve its sustainability and stability in order to achieve the purpose of improving production efficiency.

[0062] Since the working medium of the centrifugal steam compressor is water vapor, this design sets a first cooling pipe 4 outside the compressor to directly use the water vapor of the compressor itself. The second cooling pipe introduces high-pressure gas through the first-level exhaust gas for cooling, and then transfers energy with the hot air generated by industrial waste heat through the evaporator 15, so that the industrial high-temperature hot air is cooled into cold air as the source of cooling air (cold air).

[0063] The blower 17 is used to introduce cold air into the compressor. The cold air first flows through the first-stage radial bearing housing to remove the heat of the bearing, and then passes through the spiral cooling channel on the cylinder to remove the high-temperature heat generated by the motor stator and is quickly sent out of the compressor. The cold air absorbs heat and heats up again to become high-temperature hot air, and then passes through the atomizing nozzle to enter the secondary compression link and mix with the high-temperature water vapor to continue the secondary compression.

[0064] The high-temperature hot air source can utilize the waste heat from industrial production to make the compressor more environmentally friendly and improve energy utilization.

[0065] In the description of the invention, it should be noted that, unless otherwise specified, the meaning of "plurality" is two or more; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0066] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A cooling device, characterized in that, Comprising: A cooling pipeline, which includes a first cooling pipe and a second cooling pipe, and there is a heat exchange section between the first cooling pipe and the second cooling pipe; A cooling assembly, which is arranged in the first cooling pipe to cool a first medium in the first cooling pipe; and the first medium cools a second medium in the second cooling pipe at the heat exchange section; A driving device for the second medium is arranged in the second cooling pipe, and the driving device is a blower; The first cooling pipe includes an introducing section and an intermediate section, the cooling assembly is located in the intermediate section, and the axes of the introducing section and the intermediate section form an acute angle; The second cooling pipe includes a second heat exchanger, and the first cooling pipe passes through the second heat exchanger to enable heat exchange between the first medium and the second medium; The first cooling pipe further includes a reflux branch, and the first cooling pipe extends and communicates with the first cooling pipe upstream of the cooling assembly after passing through the second heat exchanger to form the reflux branch; The inlet end of the first cooling pipe communicates with the first-stage compression chamber of the compressor.

2. The cooling device according to claim 1, characterized in that, The cooling assembly is a first heat exchanger, and a coolant is arranged in the first heat exchanger, and the first cooling pipe passes through the first heat exchanger.

3. The cooling device according to claim 2, characterized in that, At least a part of the section of the first cooling pipe located in the first heat exchanger is a bent pipe.

4. The cooling device according to claim 2, wherein The coolant is cold water.

5. The cooling device according to claim 1, characterized in that, A one-way valve is arranged in the reflux branch.

6. A steam compressor, characterized in that, Including a first-stage volute, a motor cylinder, a motor stator, a hydrodynamic gas bearing, a second-stage radial bearing support, a second-stage diffuser and the cooling device according to any one of claims 1-5; the inlet end of the first cooling pipe communicates with the port of the first-stage volute or inside the volute, and the outlet end of the second cooling pipe communicates with the inside of the compressor.

7. The steam compressor according to claim 6, wherein The inlet end of the first cooling pipe is arranged on the first-stage volute, and the outlet end of the second cooling pipe is arranged on the motor cylinder.

8. The steam compressor according to claim 6 or 7, characterized in that, Air outlet openings are symmetrically formed on the second-stage radial bearing support.

9. The steam compressor according to claim 8, wherein, Atomizing nozzles are symmetrically arranged on the second-stage diffuser.

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