Centrifugal compressor and refrigeration device

Abstract

The present application relates to the technical field of compressors, and discloses a centrifugal compressor and a refrigeration device. The centrifugal compressor comprises: a housing, which is provided with a gas inlet and a gas outlet; a centrifugal compression mechanism, which is located in the housing and used for pressurizing a fluid flowing in from the gas inlet and then flowing out of the housing from the gas outlet; a main shaft, which extends in the vertical direction and is arranged in the housing, wherein the main shaft can rotate around the axis thereof; a bearing assembly, which is arranged on the outer side of the main shaft in a sleeving manner; and a centrifugal pump, which is arranged on the outer side of the main shaft in a sleeving manner and can rotate along with the main shaft. The housing defines lubricating channels and an oil cavity, the lubricating channels are communicated with the oil cavity and the bearing assembly, the centrifugal pump is communicated with the oil cavity, and the centrifugal pump can drive oil to circularly flow between the oil cavity and the bearing assembly through the lubricating channels. The coaxial centrifugal pump arranged on the vertical main shaft is used as an oil pump, omitting an oil pump driven by a motor, reducing the power consumption of the oil pump, and improving the efficiency of the compressor.

Description

Centrifugal compressors and refrigeration equipment

[0001] This application is based on the Chinese patent application with application number 202311705316.6 and application date December 12, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0002] The present application relates to the technical field of compressors, for example, to a centrifugal compressor and refrigeration equipment. Background Art

[0003] Currently, centrifugal compressors are the core components of chillers. Low-temperature, low-pressure refrigerant gas is compressed by the centrifugal compressor into high-temperature, high-pressure refrigerant gas. This high-temperature, high-pressure refrigerant gas then passes through the condenser, removing heat and condensing into a high-temperature, high-pressure refrigerant liquid. The refrigerant liquid then undergoes isenthalpic expansion through expansion devices such as expansion valves, transforming into a low-temperature, low-pressure refrigerant gas-liquid mixture. This low-temperature, low-pressure refrigerant gas-liquid mixture enters the evaporator, absorbing heat and evaporating into low-temperature, low-pressure refrigerant gas. The refrigerant gas is then drawn back into the centrifugal compressor for compression and enters the next cycle. Throughout this process, the refrigerant absorbs heat in the evaporator and releases heat in the condenser, resulting in heat transfer and cooling.

[0004] To lubricate the bearings, existing centrifugal compressors require a separate electric oil pump to circulate lubricating oil from the oil tank to each bearing. This pump consumes electricity, reducing compressor efficiency. Furthermore, existing centrifugal compressors are typically horizontal (with the main shaft axis horizontal) and typically have several sets of bearings. These bearings bear the weight of the compressor rotor, a significant load that reduces their service life.

[0005] A centrifugal compressor is disclosed in the related art, in particular, a vertical centrifugal compressor suitable for vertical arrangement, which includes: a casing, the casing having a fluid inlet and a fluid outlet, the fluid inlet being located at the top of the casing; a motor assembly, the motor assembly being arranged in the casing and including a stator and a rotor, the rotor including a vertically arranged rotor shaft, the rotor shaft including a lower end and an upper end; a centrifugal compression mechanism, the impeller of the centrifugal compression mechanism is connected to the rotor shaft to be driven by the motor assembly, the centrifugal compression mechanism is arranged downstream of the fluid inlet to receive the fluid, compress and pressurize the fluid and output the pressurized fluid in a direction away from the motor assembly; a guide, the guide receives the pressurized fluid from the centrifugal compression mechanism and defines a flow channel alone or together with part of the casing, the flow channel being configured so that the pressurized fluid from the centrifugal compression mechanism passes through and cools the motor assembly and is discharged from the fluid outlet.

[0006] The lower end of the rotor shaft may be located in an oil sump, and the rotor shaft defines an axially or slightly inclined oil passage therein. The rotor shaft may be hollow, with the oil passage therein being straight (along the axial direction of the rotor shaft) or inclined. The rotor shaft has radial through-holes at positions corresponding to the first and second bearings, respectively. During operation of the centrifugal compressor, the rotation of the rotor shaft generates negative pressure in the oil passages, thereby drawing oil from the oil sump through the oil passages in the direction of the arrows. Due to centrifugal force, the oil flows out of the radial through-holes, thereby lubricating the first and second bearings.

[0007] During the implementation of the embodiments of the present disclosure, it was found that at least the following problems exist in the related art:

[0008] The centrifugal compressor in the related art uses the negative pressure generated by the rotation of the rotor shaft (corresponding to the main shaft of this application) to achieve the circulation of oil. The oil moves by using the negative pressure of the rotor shaft, and the oil flows into the first bearing and the second bearing from the perforations of the rotor shaft. In this way, the rotor shaft has a hollow structure, which reduces the strength of the rotor shaft, reduces the service life of the rotor shaft, and affects the stable operation of the compressor.

[0009] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field.

[0010] Summary of the Invention

[0011] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0012] Embodiments of the present disclosure provide a centrifugal compressor and a refrigeration device to increase the service life of a rotor shaft of the centrifugal compressor, thereby ensuring the operating stability of the compressor.

[0013] An embodiment of the present disclosure provides a centrifugal compressor, which includes: a shell having an air inlet and an air outlet; a centrifugal compression mechanism located in the shell, for pressurizing the fluid flowing into the air inlet and allowing the fluid to flow out of the shell from the air outlet; a main shaft extending vertically and arranged in the shell, and the main shaft can rotate around its axis; a bearing assembly, sleeved on the outside of the main shaft; a centrifugal pump, sleeved on the outside of the main shaft, and can rotate with the main shaft; wherein the shell defines a lubrication channel and an oil chamber, the lubrication channel connects the oil chamber and the bearing assembly, the centrifugal pump is connected to the oil chamber, and the centrifugal pump can drive the oil to circulate between the oil chamber and the bearing assembly through the lubrication channel.

[0014] Optionally, the centrifugal pump is located below the bearing assembly, and the centrifugal pump includes: a centrifugal pump impeller, located at the bottom of the casing, sleeved on the outside of the main shaft, and capable of rotating with the main shaft; a centrifugal pump casing, connected to the bottom wall of the casing, sleeved on the outside of the centrifugal pump impeller, and the centrifugal pump casing is provided with an oil outlet; wherein, the lubrication channel includes a first lubrication channel and a second lubrication channel, the inlet of the first lubrication channel is connected to the oil outlet, the outlet of the first lubrication channel is connected to the bearing assembly, the inlet of the second lubrication channel is connected to the bearing assembly, and the outlet of the second lubrication channel is connected to the oil chamber, and when the centrifugal pump impeller rotates with the main shaft, the driving oil circulates in the centrifugal pump casing, the first lubrication channel, the bearing assembly, the second lubrication channel and the oil chamber in sequence.

[0015] Optionally, the centrifugal pump further includes: a centrifugal pump bearing, which is provided between the centrifugal pump casing and the main shaft, and the centrifugal pump bearing is located in the oil cavity and immersed in the oil in the oil cavity.

[0016] Optionally, the bearing assembly includes: a radial bearing, which is sleeved on the outside of the main shaft; a thrust bearing, which is sleeved on the outside of the main shaft and is spaced below the radial bearing; wherein the radial bearing and the thrust bearing are arranged in parallel between the outlet of the first lubrication channel and the inlet of the second lubrication channel.

[0017] Optionally, the shell further defines a circulation channel and a volute, the volute is configured with an air outlet, the circulation channel connects the air inlet and the volute, the centrifugal compression mechanism is located above the bearing assembly, the centrifugal compression mechanism includes: a first-stage impeller, which is sleeved on the outside of the main shaft and can rotate with the main shaft, and is located at the air inlet; a second-stage impeller, which is sleeved on the outside of the main shaft, is located below the first-stage impeller, and can rotate with the main shaft, when the first-stage impeller and the second-stage impeller rotate, they can drive the fluid from the air inlet along the circulation channel and out of the air outlet; wherein, a balancing chamber is configured on the side of the second-stage impeller facing the bearing assembly, and the balancing chamber is connected with the volute through a balancing flow channel to balance the pressure of the balancing chamber and the volute.

[0018] Optionally, the centrifugal compressor further includes: a balancing disk, which is arranged on the lower side of the secondary impeller, and the balancing disk and the lower end surface of the secondary impeller enclose a balancing cavity.

[0019] Optionally, the air inlet is arranged at the top of the shell, and the air outlet is arranged in the middle of the shell, and the circulation channel includes: a first-stage diffuser, the inlet of the first-stage diffuser is connected to the air inlet, and the first-stage diffuser at least partially extends in the horizontal direction away from the main axis; a first-stage bend, the inlet of the first-stage bend is connected to the outlet of the first-stage diffuser; a first-stage reflower, the inlet of the first-stage reflower is connected to the outlet of the first-stage bend, and the outlet of the first-stage reflower is connected to the air outlet, and the first-stage reflower includes an upper part and a lower part, the upper part at least partially extends in the horizontal direction and toward the main axis, and the lower part is close to the main axis and extends at least partially in the vertical direction; wherein, the first-stage bend is connected between the outlet of the first-stage diffuser and the inlet of the first-stage bend, the first-stage bend is arc-shaped, and the arc-shaped opening faces the main axis.

[0020] Optionally, the centrifugal compressor includes: a labyrinth seal, and a labyrinth seal is provided at least one of between the air inlet and the first-stage impeller, between the chamber where the first-stage impeller is located and the main shaft, between the second-stage impeller and the casing, between the balance chamber and the main shaft, and between the balance disk and the casing.

[0021] Optionally, the centrifugal compressor further includes: a shaft seal, provided between the main shaft and the bottom of the casing, for preventing oil from flowing to the outside.

[0022] An embodiment of the present disclosure further provides a refrigeration device, which includes a centrifugal compressor as described in any one of the above embodiments.

[0023] The centrifugal compressor and refrigeration equipment provided by the embodiments of the present disclosure can achieve the following technical effects:

[0024] In the disclosed embodiment, the main shaft extends in the vertical direction, which can reduce the load borne by the bearing assembly, improve the bearing capacity of the bearing assembly, and increase the service life of the bearing assembly. The oil in the oil chamber driven by the centrifugal pump flows through the lubrication channel to the bearing assembly for lubricating the bearing assembly. The oil after lubricating the bearing assembly flows back into the oil chamber under the action of gravity, and then circulates under the action of the centrifugal pump. By setting a coaxial centrifugal pump on the vertical main shaft as an oil pump, the oil pump driven by the electric motor is eliminated, the power consumption of the oil pump is reduced, and the efficiency of the compressor is improved. In addition, the centrifugal pump is used as the oil pump. The centrifugal pump acts as an independent driving component to drive the oil to flow along the lubrication channel to the bearing. The centrifugal pump is more reliable and can reduce the difference in oil output in the height direction, thereby ensuring the oil supply efficiency of the bearing assembly and further ensuring the working efficiency of the compressor.

[0025] In addition, a centrifugal pump is used to drive the oil, which does not require changes to the interior of the main shaft, does not reduce the strength of the main shaft, increases the service life of the main shaft, and can ensure the stability of the compressor operation.

[0026] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] One or more embodiments are exemplarily described by corresponding drawings. These exemplary descriptions and drawings do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation. In addition,

[0028] FIG1 is a schematic cross-sectional view of a centrifugal compressor according to an embodiment of the present disclosure;

[0029] FIG2 is an enlarged structural diagram of part A in FIG1 ;

[0030] FIG3 is an enlarged structural diagram of part B in FIG1 ;

[0031] FIG4 is a partial cross-sectional schematic diagram of a compressor provided by an embodiment of the present disclosure;

[0032] FIG5 is a partial cross-sectional schematic diagram of another compressor provided by an embodiment of the present disclosure.

[0033] Reference numerals: 10. Casing; 101. Air inlet; 102. Air outlet; 1021. Volute; 103. First-stage impeller; 104. Second-stage impeller; 105. First-stage diffuser; 106. First-stage bend; 107. First-stage return flow collector; 20. Main shaft; 201. Centrifugal bearing; 202. Thrust bearing; 30. Centrifugal pump; 301. Centrifugal pump impeller; 302. Centrifugal pump casing; 3021. Oil outlet; 3022. Oil level; 303. Centrifugal pump bearing; 304. First lubrication channel; 305. Second lubrication channel; 306. Oil chamber; 40. Balancing disc; 401. Balancing chamber; 402. Balancing flow channel; 50. Shaft seal; 501. First labyrinth seal; 502. Second labyrinth seal; 503. Third labyrinth seal; 504. Fourth labyrinth seal; 505. Fifth labyrinth seal. DETAILED DESCRIPTION

[0034] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The accompanying drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0035] In the description and claims of the embodiments of the present disclosure, as well as in the accompanying drawings, the terms "first," "second," and the like are used to distinguish similar items and are not necessarily used to describe a particular order or precedence. It should be understood that such terms are interchangeable where appropriate to describe the embodiments of the present disclosure. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0036] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to having a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0037] Furthermore, the terms "disposed," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a removable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or an internal connection between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this disclosure based on the specific circumstances.

[0038] Unless otherwise stated, the term "plurality" means two or more.

[0039] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0041] The arrow flow direction in FIG4 represents the flow direction of oil in the centrifugal compressor; the arrow flow direction in FIG5 represents the flow direction of fluid inside the centrifugal compressor.

[0042] As shown in Figures 1 to 5 , an embodiment of the present disclosure provides a centrifugal compressor, comprising a housing 10 and a main shaft 20. The housing 10 has an air inlet 101 and an air outlet 102. The main shaft 20 extends vertically and is disposed within the housing 10. The main shaft 20 is rotatable about its axis. The centrifugal compressor also includes a centrifugal compression mechanism for pressurizing fluid flowing into the air inlet 101 and allowing it to flow out of the housing 10 through the air outlet 102.

[0043] In the disclosed embodiment, the centrifugal compression mechanism can pressurize the low-temperature, low-pressure refrigerant flowing from the evaporator to the air inlet 101 into a high-temperature, high-pressure refrigerant, and then make the high-temperature, high-pressure refrigerant flow to the condenser, thereby realizing the refrigeration cycle of the refrigeration system.

[0044] Optionally, as shown in FIG. 1 , the centrifugal compressor further includes a bearing assembly, which is sleeved on the outer side of the main shaft 20 .

[0045] The bearing assembly is arranged on the outside of the main shaft 20 to bear the load caused by the rotation of the main shaft 20 and ensure the rotational stability of the main shaft 20. When the main shaft 20 is arranged horizontally, the main shaft 20 generally needs to be provided with several sets of bearings. This causes some bearings to bear the weight of the compressor rotor, resulting in a larger load, which reduces the service life of the bearings. In the embodiment of the present disclosure, the main shaft 20 extends in a vertical direction, that is, the main shaft 20 is perpendicular to the horizontal plane to form a vertical main shaft 20, which can reduce the load borne by the bearing assembly, improve the bearing's load-bearing capacity, and thus increase the service life of the bearing.

[0046] Optionally, as shown in Figure 2, the centrifugal compressor also includes a centrifugal pump 30, which is sleeved on the outside of the main shaft 20 and can rotate with the main shaft 20; wherein, the housing 10 defines a lubrication channel and an oil chamber 306, the lubrication channel connects the oil chamber 306 and the bearing assembly, the centrifugal pump 30 is connected to the oil chamber 306, and the centrifugal pump 30 can drive the oil to circulate between the oil chamber 306 and the bearing assembly through the lubrication channel.

[0047] In the embodiment of the present disclosure, the centrifugal pump 30 can rotate with the main shaft 20, and the centrifugal pump 30 is connected to the oil chamber 306. In this way, when the centrifugal pump 30 rotates, it can drive the oil in the oil chamber 306 to flow into the lubrication channel, and then flow from the lubrication channel to the bearing assembly to lubricate the bearing assembly. After lubricating the bearing assembly, the oil can flow back to the oil chamber 306 along the lubrication channel under the action of gravity and the driving force of the centrifugal pump 30. The oil returned to the oil chamber 306 can flow to the bearing assembly under the driving action of the centrifugal pump 30, thus realizing the circulation of the oil circuit. The centrifugal compressor of the embodiment of the present disclosure does not require an additional motor, which reduces the energy consumption of the compressor. Moreover, the use of the centrifugal pump 30 to drive the oil flow can increase the driving force of the oil, reduce the supply difference of the lubrication channel in the height direction, improve the lubrication uniformity of the bearing assembly, and thus improve the working efficiency of the compressor.

[0048] Optionally, the centrifugal pump 30 is disposed at the bottom of the housing 10 .

[0049] In the embodiment of the present disclosure, the centrifugal pump 30 is disposed at the bottom of the housing 10 , so that the arrangement of the centrifugal pump 30 does not interfere with the operation of the centrifugal compression mechanism, nor does it affect the rotation of the bearing assembly.

[0050] Optionally, the oil chamber 306 is provided at the bottom of the housing 10 .

[0051] In the disclosed embodiment, the oil chamber 306 is also provided at the bottom of the housing 10 . The oil accumulates at the bottom of the housing 10 under the action of gravity and does not leak to other components, which also facilitates cooperation with the centrifugal pump 30 .

[0052] Optionally, the centrifugal pump 30 includes a centrifugal pump impeller 301 and a centrifugal pump casing 302. The centrifugal pump impeller 301 is located at the bottom of the housing 10, is sleeved on the outside of the main shaft 20, and can rotate with the main shaft 20; the centrifugal pump casing 302 is connected to the bottom wall of the housing 10, is sleeved on the outside of the centrifugal pump impeller 301, and the centrifugal pump casing 302 is provided with an oil outlet 3021; ​​wherein, the lubrication channel includes a first lubrication channel 304 and a second lubrication channel 305, the inlet of the first lubrication channel 304 is connected to the oil outlet 3021, the outlet of the first lubrication channel 304 is connected to the bearing assembly, the inlet of the second lubrication channel 305 is connected to the bearing assembly, and the outlet of the second lubrication channel 305 is connected to the oil chamber 306. When the centrifugal pump impeller 301 rotates with the main shaft 20, the driving lubricating oil circulates in the centrifugal pump casing 302, the first lubrication channel 304, the bearing assembly, the second lubrication channel 305 and the oil chamber 306 in sequence.

[0053] In the disclosed embodiment, the centrifugal pump impeller 301 is sleeved on the outside of the main wheel so that the centrifugal pump impeller 301 can rotate coaxially with the main shaft 20. The rotation of the blades of the centrifugal pump impeller 301 generates a driving force, which in turn drives the oil to flow along the lubrication channel. The centrifugal pump casing 302 is sleeved on the outside of the centrifugal pump impeller 301 to protect the centrifugal pump impeller 301. The centrifugal pump casing 302 has an oil outlet 3021. When the centrifugal pump impeller 301 rotates, the oil in the oil chamber 306 is sucked into the centrifugal pump casing 302, and then flows from the oil outlet 3021 into the first lubrication channel 304. The first lubrication channel 304 sends the oil to the bearing assembly for lubrication of the bearing assembly. The lubricated oil flows back to the oil chamber 306 along the second lubrication channel 305 under the action of gravity. After the oil chamber 306 cools, it enters the centrifugal pump 30 again to form an oil circuit.

[0054] Optionally, the centrifugal pump 30 is located in the oil chamber 306 , which makes it easier for the centrifugal pump 30 to absorb the oil in the oil chamber 306 .

[0055] Optionally, the cross-sectional area of ​​the oil chamber 306 is annular, and the cross-sectional area of ​​the oil chamber 306 is larger than the cross-sectional area of ​​the centrifugal pump 30, so that the oil chamber 306 has a larger space, which is convenient for cooling the lubricated oil and also for storing the oil.

[0056] Optionally, the centrifugal pump 30 is located below the bearing assembly to prevent the centrifugal pump 30 from affecting the operation of the bearing assembly.

[0057] Optionally, the first lubrication channel 304 at least partially extends in the vertical direction to transport the oil outlet 3021 of the centrifugal pump 30 at the bottom to the bearing assembly above.

[0058] Optionally, the second lubrication channel 305 extends in a vertical direction, and an outlet end of the second lubrication channel 305 is located above the oil chamber 306 , so that the oil flowing into the second lubrication channel 305 can quickly flow into the oil chamber 306 under the action of gravity.

[0059] Optionally, the centrifugal pump 30 further includes a centrifugal pump bearing 303 . The centrifugal pump bearing 303 is disposed between the centrifugal pump casing 302 and the main shaft 20 . The centrifugal pump bearing 303 is located in the oil cavity 306 and immersed in the oil in the oil cavity 306 .

[0060] In the disclosed embodiment, the centrifugal pump bearing 303 is disposed between the centrifugal pump housing 302 and the main shaft 20, thereby facilitating the rotation of the main shaft 20 relative to the centrifugal pump housing 302. The centrifugal pump bearing 303 is immersed in oil, which can lubricate the centrifugal pump bearing 303 and ensure the normal operation of the centrifugal pump bearing 303.

[0061] It can be understood that the oil level 3022 in the oil chamber 306 is higher than the centrifugal pump bearing 303, so that the centrifugal pump bearing 303 can be immersed in the oil.

[0062] Optionally, the top of the oil chamber 306 is higher than the centrifugal pump bearing 303 , which can provide sufficient space to store oil and enable the centrifugal pump bearing 303 to enter the oil.

[0063] Optionally, the centrifugal pump bearing 303 is connected between the upper end of the centrifugal pump casing 302 and the main shaft 20, and the lower portion of the centrifugal pump casing 302 is connected to the bottom wall of the housing 10. This allows the centrifugal pump casing 302 to be fixed within the casing without affecting the rotation of the main shaft 20, so that the main shaft 20 can drive the centrifugal pump impeller 301 to rotate.

[0064] Optionally, there is a gap between the bottom wall of the centrifugal pump casing 302 and the bottom wall of the housing 10, so that the oil in the oil cavity 306 can be distributed more evenly, the storage capacity of the oil cavity 306 is increased, and the cooling speed of the oil is accelerated.

[0065] Optionally, the bearing assembly includes a radial bearing 201 and a thrust bearing 202, wherein the radial bearing 201 is sleeved on the outside of the main shaft 20; the thrust bearing 202 is sleeved on the outside of the main shaft 20 and is spaced below the radial bearing 201; wherein the radial bearing 201 and the thrust bearing 202 are arranged in parallel between the outlet of the first lubrication channel 304 and the inlet of the second lubrication channel 305.

[0066] In the disclosed embodiment, a radial bearing 201 and a thrust bearing 202 are arranged on the outside of the main shaft 20 in sequence from top to bottom. The radial bearing 201 is used to bear the radial load of the main shaft 20 and the rotation of the main shaft 20, while the thrust bearing is used to bear the axial load and rotation of the main shaft 20. The arrangement of the two bearings can support the radial and axial loads of the main shaft 20 and ensure the rotation of the main shaft 20. The main shaft 20 is arranged to extend vertically, which can reduce the radial load borne by the radial bearing 201 and improve the load-bearing capacity and service life of the radial bearing 201. The radial bearing 201 and the thrust bearing 202 are arranged in parallel between the outlet of the first lubrication channel 304 and the inlet of the second lubrication channel 305. This can ensure the oil supply to each bearing, thereby ensuring the lubrication effect of each bearing and improving the working efficiency of the compressor.

[0067] Optionally, there are multiple radial bearings 201, which are spaced apart in the vertical direction. This arrangement can improve the radial support provided by the bearings to the main shaft 20, disperse the load of each radial bearing 201, and extend the service life of the radial bearings 201.

[0068] Optionally, there are multiple thrust bearings 202, which are spaced apart in a vertical direction. Thus, the thrust bearings 202 are disposed below the radial bearing 201, and the thrust bearings 202 bear the axial load of the main shaft 20. Providing multiple thrust bearings 202 can improve the axial load bearing capacity of the main shaft 20.

[0069] Optionally, the plurality of radial bearings 201 include a first radial bearing and a second radial bearing, with the first radial bearing positioned above the second radial bearing. The vertical spacing between the first and second radial bearings is greater than the vertical spacing between the second radial bearing and the thrust bearing 202. This allows the two radial bearings 201 to disperse the radial load on the main shaft 20, while the thrust bearing 202 is positioned closer to the second radial bearing to better withstand axial loads.

[0070] Optionally, the plurality of thrust bearings 202 include a first thrust bearing and a second thrust bearing, with the first thrust bearing positioned above the second thrust bearing. In the vertical direction, the distance between the second radial bearing and the first thrust bearing is greater than the distance between the first and second thrust bearings. This allows the two thrust bearings 202 to be closer together, and their lower placement can better bear the axial load of the main shaft 20, ensuring the rotational stability of the main shaft 20.

[0071] Optionally, when there are multiple radial bearings 201 , the multiple radial bearings 201 are arranged in parallel between the outlet of the first lubrication channel 304 and the inlet of the second lubrication channel 305 .

[0072] Optionally, when there are multiple thrust bearings 202 , the multiple thrust bearings 202 are arranged in parallel between the outlet of the first lubrication channel 304 and the inlet of the second lubrication channel 305 .

[0073] Optionally, as shown in Figures 3 and 5, the shell 10 further defines a circulation channel and a volute 1021, the volute 1021 is configured with an air outlet 102, the circulation channel connects the air inlet 101 and the volute 1021, the centrifugal compression mechanism is located above the bearing assembly, the centrifugal compression mechanism includes a first-stage impeller 103 and a second-stage impeller 104, the first-stage impeller 103 is sleeved on the outside of the main shaft 20, and can rotate with the main shaft 20; the second-stage impeller 104 is sleeved on the outside of the main shaft 20, located below the first-stage impeller 103, and can rotate with the main shaft 20, when the first-stage impeller 103 and the second-stage impeller 104 rotate, they can drive the fluid to flow out from the air inlet 101 along the circulation channel and out of the air outlet 102.

[0074] In the disclosed embodiment, the fluid can be gas. The high-speed rotation of the first-stage impeller 103 of the centrifugal compressor accelerates the gas into the flow channel. The high-speed gas decelerates within the flow channel. According to Bernoulli's principle, dynamic pressure is converted into static pressure, and kinetic energy is converted into pressure energy, increasing the gas pressure and forming a first-stage compressed gas. The first-stage compressed gas passes through the flow channel and enters the second-stage impeller 104, where it undergoes the same process as above to achieve a second-stage pressurization.

[0075] It should be noted that the centrifugal compressor of the present application can also be provided with more impellers, and a subsequent multi-stage impeller can be provided to repeat the above process to achieve subsequent supercharging processes such as three-stage supercharging and four-stage supercharging.

[0076] Optionally, a balancing chamber 401 is configured on a side of the secondary impeller 104 facing the bearing assembly, and the balancing chamber 401 is communicated with the volute 1021 through a balancing flow channel 402 to balance the pressures in the balancing chamber 401 and the volute 1021 .

[0077] In the embodiment of the present disclosure, the arrangement of the balancing chamber 401 and the balancing flow channel 402 makes the pressures of the volute 1021 and the balancing chamber 401 the same. In this way, after the compressor is running, a certain pressure is generated in the volute 1021, and the same pressure is also generated through the balancing flow channel 402 and the balancing chamber 401. These pressures act on the back of the secondary impeller 104, that is, the lower end face of the secondary impeller 104. The arrangement of the balancing chamber 401 can offset part of the load of the thrust bearing 202. Since the main shaft 20 is placed vertically, the radial bearing 201 only plays a "supporting" role, so the load is very small. Therefore, by the arrangement of the vertical main shaft 20 and the balancing chamber 401, the loads of the radial bearing 201 and the thrust bearing 202 are reduced, and the service life of the radial bearing 201 and the thrust bearing 202 is increased.

[0078] Optionally, the balancing chamber 401 is annular and is disposed around the main shaft 20 , so that the balancing chamber 401 can better balance the pressure of the secondary impeller 104 and reduce the load of the thrust bearing 202 .

[0079] Optionally, the cross-sectional area of ​​the balancing chamber 401 is the same as or similar to the cross-sectional area of ​​the secondary impeller 104 , so that the balancing chamber 401 can balance the pressure on the back of the secondary impeller 104 as widely as possible, thereby reducing the load on the thrust bearing 202 .

[0080] Optionally, the centrifugal compressor further includes a balancing disc 40 , which is disposed on the lower side of the secondary impeller 104 . The balancing disc 40 and the lower end surface of the secondary impeller 104 enclose a balancing cavity 401 .

[0081] In the embodiment of the present disclosure, the balancing disc 40 is disposed on the lower side of the secondary impeller 104 to construct a balancing chamber 401 to reduce the pressure in the balancing chamber 401 .

[0082] For example, as shown in FIG3 , the balancing disc 40 is connected to the lower side of the outer edge of the secondary impeller 104 and extends downward to form a balancing chamber 401 .

[0083] Optionally, the air inlet 101 is provided at the top of the housing 10, the air outlet 102 is provided at the middle of the housing 10, and the flow channel includes a first-stage diffuser 105, a first-stage bend 106 and a first-stage reflow device 107 which are sequentially connected along the fluid flow direction, the inlet of the first-stage diffuser 105 is connected to the air inlet 101, and the first-stage diffuser 105 at least partially extends in the horizontal direction away from the main axis 20; the inlet of the first-stage bend 106 is connected to the outlet of the first-stage diffuser 105; the first-stage reflow device 107 The inlet is connected to the outlet of the first-level bend 106, and the outlet of the first-level returner 107 is connected to the air outlet 102. The first-level returner 107 includes an upper part and a lower part. The upper part at least partially extends in the horizontal direction and toward the main shaft 20, and the lower part is close to the main shaft 20 and extends at least partially in the vertical direction; wherein, the first-level bend 106 is connected between the outlet of the first-level diffuser 105 and the inlet of the first-level bend 106, and the first-level bend 106 is arc-shaped, and the arc-shaped opening faces the main shaft 20.

[0084] In the disclosed embodiment, the first-stage impeller 103 of the centrifugal compressor accelerates the gas flowing into the air inlet 101 through high-speed rotation and flings it into the first-stage diffuser 105. The first-stage diffuser extends horizontally for a certain length to decelerate the high-speed gas within the first-stage diffuser 105. According to Bernoulli's principle, dynamic pressure is converted into static pressure, and kinetic energy is converted into pressure energy, thereby increasing the gas pressure and forming a first-stage compressed gas. The first-stage compressed gas passes through the first-stage bend 106 and the first-stage return flow device 107 and enters the second-stage impeller 104. After the same process as above, the second-stage supercharging is achieved, and the second-stage supercharged gas flows out of the outlet 102.

[0085] Optionally, the centrifugal compressor further includes a labyrinth seal, and a labyrinth seal is provided at least one of between the air inlet 101 and the first-stage impeller 103, between the chamber where the first-stage impeller 103 is located and the main shaft 20, between the second-stage impeller 104 and the casing 10, between the balancing chamber 401 and the main shaft 20, and between the balancing disk 40 and the casing 10.

[0086] In the disclosed embodiment, the labyrinth seal can seal multiple components to avoid air or oil leakage. The labyrinth seal is a sealing ring with a labyrinth-like gap formed by many teeth or grooves, which produces a throttling effect on the sealed medium and plays a sealing role. The labyrinth seal has good sealing performance, does not require lubrication, is frictionless, is easy to maintain, has a long service life, does not require the use of other sealing materials, and is used in compressors. It can adapt to the high temperature and high pressure sealing environment of centrifugal compressors and has a significant sealing effect.

[0087] Optionally, the labyrinth seal includes a first labyrinth seal 501 , which is disposed between the air inlet 101 and the wheel cover of the first-stage impeller 103 . The first labyrinth seal 501 is used to prevent air leakage from the first-stage impeller 103 toward the air inlet 101 .

[0088] Optionally, the labyrinth seal includes a second labyrinth seal 502, which is arranged between the chamber where the first-stage impeller 103 is located and the main shaft 20. Specifically, the second labyrinth seal 502 is located between the main shaft 20 and the casing 10. The second labyrinth seal 502 is arranged around the main shaft 20, and the second labyrinth seal 502 is connected to the chamber where the first-stage impeller 103 is located. The second labyrinth seal 502 is used to prevent the pressurized gas of the first-stage impeller 103 from leaking into the axial gap of the main shaft 20.

[0089] Optionally, the labyrinth seal includes a third labyrinth seal 503 , which is provided between the secondary impeller 104 and the casing 10 to prevent air leakage from the secondary impeller 104 to the primary impeller 103 .

[0090] Optionally, the labyrinth seal includes a fourth labyrinth seal 504 , which is provided between the balancing chamber 401 and the main shaft 20 , and is used to prevent air leakage from the balancing chamber 401 to the shaft gap.

[0091] Optionally, the labyrinth seal includes a fifth labyrinth seal 505 , which is provided between the balancing disc 40 and the housing 10 . The fifth labyrinth seal 505 is used to prevent the balancing chamber 401 from leaking toward the flow channel.

[0092] Optionally, the centrifugal compressor further includes a shaft seal 50 , which is provided between the main shaft 20 and the bottom of the casing 10 to prevent oil from flowing to the outside.

[0093] In the disclosed embodiment, the shaft seal 50 is sealed between the main shaft 20 and the bottom of the housing 10 , thereby preventing the oil in the oil chamber 306 from flowing to the outside through the bottom connection between the main shaft 20 and the housing 10 .

[0094] An embodiment of the present disclosure further provides a refrigeration device, which includes a centrifugal compressor according to any one of the above embodiments.

[0095] The refrigeration equipment provided by the embodiment of the present disclosure includes the centrifugal compressor of any one of the above embodiments, and thus has the beneficial effects of the centrifugal compressor of any one of the above embodiments, which will not be described in detail here.

[0096] Optionally, the refrigeration equipment may be a water chiller, an air conditioner, or the like equipped with a centrifugal compressor.

[0097] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless expressly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A centrifugal compressor, characterized in that: include: A housing having an air inlet and an air outlet; A centrifugal compression mechanism is located in the housing and is used to pressurize the fluid flowing into the air inlet and then flow out of the housing from the air outlet; A main shaft extending vertically and disposed in the housing, the main shaft being capable of rotating around its axis; A bearing assembly is sleeved on the outer side of the main shaft; The centrifugal pump is sleeved on the outside of the main shaft and can rotate with the main shaft; The shell defines a lubrication channel and an oil cavity, the lubrication channel connects the oil cavity and the bearing assembly, the centrifugal pump is connected to the oil cavity, and the centrifugal pump can drive the oil to circulate between the oil cavity and the bearing assembly through the lubrication channel.

2. The centrifugal compressor according to claim 1, characterized in that: The centrifugal pump is located below the bearing assembly and includes: The centrifugal pump impeller is located at the bottom of the casing, sleeved on the outside of the main shaft, and can rotate with the main shaft; The centrifugal pump casing is connected to the bottom wall of the casing and is sleeved on the outer side of the centrifugal pump impeller. The centrifugal pump casing is provided with an oil outlet; Among them, the lubrication channel includes a first lubrication channel and a second lubrication channel, the inlet of the first lubrication channel is connected to the oil outlet, the outlet of the first lubrication channel is connected to the bearing assembly, the inlet of the second lubrication channel is connected to the bearing assembly, and the outlet of the second lubrication channel is connected to the oil chamber. When the centrifugal pump impeller rotates with the main shaft, the driving oil circulates in the centrifugal pump casing, the first lubrication channel, the bearing assembly, the second lubrication channel and the oil chamber in sequence.

3. The centrifugal compressor according to claim 2, characterized in that: Centrifugal pumps also include: The centrifugal pump bearing is arranged between the centrifugal pump casing and the main shaft, and the centrifugal pump bearing is located in the oil cavity and immersed in the oil in the oil cavity.

4. The centrifugal compressor according to claim 2, characterized in that: The bearing assembly includes: The radial bearing is sleeved on the outside of the main shaft; The thrust bearing is sleeved on the outer side of the main shaft and spaced below the radial bearing; The radial bearing and the thrust bearing are arranged in parallel between the outlet of the first lubrication channel and the inlet of the second lubrication channel.

5. The centrifugal compressor according to any one of claims 1 to 4, characterized in that: The housing further defines a circulation channel and a volute, the volute is provided with an air outlet, the circulation channel communicates with the air inlet and the volute, and the centrifugal compression mechanism is located above the bearing assembly, and the centrifugal compression mechanism includes: The first-stage impeller is sleeved on the outside of the main shaft and can rotate with the main shaft, and is located at the air inlet; The secondary impeller is sleeved on the outside of the main shaft, located below the primary impeller, and can rotate with the main shaft. When the primary impeller and the secondary impeller rotate, the fluid can be driven to flow out of the air outlet from the air inlet along the flow channel; A balancing chamber is constructed on the side of the secondary impeller facing the bearing assembly, and the balancing chamber is connected to the volute through a balancing flow channel to balance the pressure of the balancing chamber and the volute.

6. The centrifugal compressor according to claim 5, characterized in that: Also includes: The balancing disc is arranged at the lower side of the secondary impeller, and the balancing disc and the lower end surface of the secondary impeller enclose a balancing cavity.

7. The centrifugal compressor according to claim 5, characterized in that: The air inlet is located at the top of the shell, the air outlet is located in the middle of the shell, and the flow channel includes: a first-stage diffuser, wherein an inlet of the first-stage diffuser is connected to the air inlet, and at least a portion of the first-stage diffuser extends in a horizontal direction away from the main axis; a primary bend, wherein an inlet of the primary bend is connected to an outlet of a primary diffuser; A primary returner, the inlet of the primary returner is connected to the outlet of the primary bend, the outlet of the primary returner is connected to the air outlet, the primary returner comprises an upper part and a lower part, the upper part at least partially extends in a horizontal direction and in a direction toward the main axis, and the lower part is close to the main axis and at least partially extends in a vertical direction; The primary bend is connected between the outlet of the primary diffuser and the inlet of the primary bend, the primary bend is arc-shaped, and the opening of the arc faces the main axis.

8. The centrifugal compressor according to claim 5, characterized in that: Also includes: A labyrinth seal is provided between at least one of the air inlet and the first-stage impeller, between the chamber where the first-stage impeller is located and the main shaft, between the second-stage impeller and the casing, between the balance chamber and the main shaft, and between the balance disk and the casing.

9. The centrifugal compressor according to any one of claims 1 to 8, characterized in that: Also includes: The shaft seal is located between the main shaft and the bottom of the housing to prevent oil from flowing to the outside.

10. A refrigeration device, characterized in that: Comprising the centrifugal compressor according to any one of claims 1 to 9.

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