CN117905721A

CN117905721A - Centrifugal compressor

Info

Publication number: CN117905721A
Application number: CN202211237658.5A
Authority: CN
Inventors: 周易; 石刚意
Original assignee: Shanghai Highly Group Co Ltd
Current assignee: Shanghai Highly Group Co Ltd
Priority date: 2022-10-10
Filing date: 2022-10-10
Publication date: 2024-04-19

Abstract

The present invention provides a centrifugal compressor, comprising: a housing including a cavity; the motor is arranged in the cavity; a driving shaft including a main shaft connected to a rotor of the motor, and a first end shaft and a second end shaft extending out of both sides of the motor in an axial direction; the first pump body and the first bearing assembly are hermetically fixed on the first end shaft through the first bearing assembly; the second pump body and the second bearing assembly are hermetically fixed on the second end shaft through the second bearing assembly; the first bearing assembly and the second bearing assembly each comprise an air bearing. The invention adopts the air suspension oilless bearing, can improve the rotating speed of the centrifugal compressor, reduce the energy consumption and improve the pneumatic performance of the compressor.

Description

Centrifugal compressor

Technical Field

The invention relates to the technical field of compressors, in particular to a centrifugal compressor.

Background

In recent years, due to the rapid development of high-speed permanent magnet synchronous motors and oilless bearing technologies, the oilless centrifugal compressor is also increasingly widely applied to the field of central air conditioning water chilling units. The oil-free centrifugal refrigeration compressor is operated to greatly improve the heat exchange efficiency of the two heat exchangers in the cycle, and the water chilling unit with the same cold quantity and excellent partial load efficiency of the centrifugal compressor is adopted to generate huge energy-saving benefit. Because of no oil, the pipeline system of the compressor configuration is very simple, which is beneficial to the parallel connection of multiple machine heads and the modular design of the unit. The most critical five-degree-of-freedom bearing control of the oil-free centrifugal compressor used at present is that the control is complex, and the magnetic suspension bearing and the magnetic suspension controller are blocked by the related technology, so that the price is high. The centrifugal compressor with the ceramic ball bearing runs by self-lubrication of the bearing, but is not suitable for high-rotation-speed occasions, and the centrifugal compressor is just a speed type compressor, so that the application range of the centrifugal compressor is relatively narrow, and the service life of the bearing is short due to long-time self-lubrication friction of the ceramic ball, so that the maintenance cost of the compressor is increased.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a centrifugal compressor, which can improve the rotating speed of the compressor and reduce the maintenance cost of the compressor.

An embodiment of the present invention provides a centrifugal compressor including: a housing including a cavity; the motor is arranged in the cavity; a driving shaft including a main shaft connected to a rotor of the motor, and a first end shaft and a second end shaft extending out of both sides of the motor in an axial direction; the first pump body and the first bearing assembly are hermetically fixed on the first end shaft through the first bearing assembly; the second pump body and the second bearing assembly are hermetically fixed on the second end shaft through the second bearing assembly; the first bearing assembly and the second bearing assembly each comprise an air bearing.

In some embodiments, the first bearing assembly comprises a first thrust bearing sleeved on the first end shaft and a first radial bearing fixedly connected to the first end of the housing;

the second bearing assembly comprises a second thrust bearing and a second radial bearing, the second thrust bearing and the second radial bearing are respectively sleeved on the first end shaft, and the second thrust bearing is fixedly connected with the second end of the shell;

the first thrust bearing, the first radial bearing, the second thrust bearing and the second radial bearing are all air suspension bearings.

In some embodiments, a first protruding portion is disposed on a side, away from the motor, of the first end shaft, a second protruding portion is disposed on a side, away from the motor, of the second end shaft, the first radial bearing is sleeved on the outer side of the first protruding portion, and the second radial bearing is sleeved on the outer side of the second protruding portion.

In some embodiments, the first pump body further comprises a first impeller and a first diffuser, and the wheel disc of the first impeller and the first diffuser are in the same plane; the first diffuser is fixed at the first end of the shell through a screw;

The second pump body further comprises a second impeller and a second diffuser, and a wheel disc of the second impeller and the second diffuser are positioned on the same plane; the second diffuser is fixed at the second end of the shell through a screw.

In some embodiments, a first set screw is further provided in the first pump body, the first set screw passing through the impeller from a first side of the first impeller and being screwed to the first end shaft;

The second pump body is internally provided with a second set screw, and the second set screw penetrates through the impeller from the first side of the second impeller and is in threaded connection with the second end shaft.

In some embodiments, the system further comprises a first volute and a second volute, the first pump body is disposed in the first volute, the second pump body is disposed in the second volute, and the first volute and the second volute are disposed opposite to each other.

In some embodiments, the sides of the first impeller and the second impeller facing the motor are each sealed by a labyrinth seal.

In some embodiments, a communication pipe is further included through which the first pump body and the second pump body communicate.

In some embodiments, a gas supplementing pipe is further arranged on the communicating pipe, and the direction of fluid in the gas supplementing pipe is the same as the direction of fluid at the outlet of the first volute.

In some embodiments, the first volute is fixedly connected with the first cavity through a first flange plate; the second cavity is fixedly connected with the second volute through a second flange plate.

The centrifugal compressor provided by the invention has the following advantages:

The present invention provides a centrifugal compressor, comprising: a housing including a cavity; the motor is arranged in the cavity; a driving shaft including a main shaft connected to a rotor of the motor, and a first end shaft and a second end shaft extending out of both sides of the motor in an axial direction; the first pump body and the first bearing assembly are hermetically fixed on the first end shaft through the first bearing assembly; the second pump body and the second bearing assembly are hermetically fixed on the second end shaft through the second bearing assembly; the first bearing assembly and the second bearing assembly each comprise an air bearing. By arranging the air suspension oilless bearing in the centrifugal compressor, the rotating speed of the compressor can be improved, the maintenance cost of the compressor can be reduced, the energy consumption can be reduced, and the pneumatic performance of the compressor can be improved.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings.

Fig. 1 is a front view of a centrifugal compressor according to an embodiment of the present invention;

FIG. 2 is a top view of a centrifugal compressor according to an embodiment of the invention;

Fig. 3 is a sectional view of a centrifugal compressor according to an embodiment of the present invention.

Reference numerals:

1. first volute of housing 91

2. Second volute of motor 92

211. Cooling groove 10 communicating pipe

3. Air supplementing pipe of driving shaft 11

31. First boss 12 junction box

32. Second boss 13 temperature/pressure sensor

41. First radial bearing 14 inlet guide vane actuator

42. Second radial bearing 15 base

51. First thrust bearing 161 coolant inlet

61. Cooling liquid outlet of first impeller 162

62. A first inlet of a second impeller 171

71. First diffuser 172 second inlet

72. The second diffuser 173 first outlet

81. First set screw

82. Second set screw

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. "or", "or" in the specification may each mean "and" or ".

Fig. 1 is a front view of a centrifugal compressor according to an embodiment of the present invention; FIG. 2 is a top view of a centrifugal compressor according to an embodiment of the present invention; fig. 3 is a sectional view of a centrifugal compressor according to an embodiment of the present invention. As shown in fig. 1 to 3, the present invention provides a centrifugal compressor, which is a two-stage centrifugal compressor, including a housing 1, a motor 2, a driving shaft 3, a first pump body, a first bearing assembly, a second pump body, and a second bearing assembly. The shell 1 comprises a cavity; the motor 2 is arranged in the cavity; the drive shaft 3 comprises a main shaft connected to the rotor of the motor, and a first end shaft and a second end shaft extending out of both sides of the motor in the axial direction; the first pump body is sealed and fixed on the first end shaft through the first bearing assembly; the second pump body is fixed on the second end shaft in a sealing way through the second bearing assembly; the first bearing assembly and the second bearing assembly each comprise an air bearing. The first bearing assembly and the second bearing assembly are configured to limit radial and axial movement of the drive shaft. The oil-free bearing of the air suspension bearing is arranged in the centrifugal compressor, so that the length of the bearing is obviously shortened, the structure of the compressor is more compact, and the occupied space is saved; the air suspension bearing is lubricated by the air film, no extra bearing control means is needed, and compared with a magnetic suspension compressor and a ceramic ball compressor, the air suspension bearing is more energy-saving and has low maintenance cost; the rotating speed of the air suspension compressor is higher and can reach more than 20 ten thousand revolutions per minute, so that the pneumatic performance of the compressor is improved.

Referring to fig. 3 again, the first bearing assembly includes a first thrust bearing 51 and a first radial bearing 41, the first thrust bearing 51 and the first radial bearing 41 are respectively sleeved on a first side and a second side of the first end shaft, and the first radial bearing 41 is fixedly connected with the first end of the housing 1. The first radial bearing 41 restricts radial movement of the drive shaft 3, and the first thrust bearing 51 restricts axial movement of the drive shaft 3.

In this embodiment, the second bearing assembly includes a second radial bearing 42, where the second radial bearing 42 is sleeved on a second side of the second end shaft, and the second radial bearing 42 is fixedly connected with a second end of the housing 1; in another embodiment, the second bearing assembly further comprises a second thrust bearing sleeved on the first side of the second end shaft. The first thrust bearing, the first radial bearing, the second thrust bearing and the second radial bearing are all air suspension bearings. The air suspension bearing is an oilless bearing, only through air film lubrication, no extra control means is needed, and compared with a centrifugal compressor provided with the magnetic suspension bearing and a centrifugal compressor provided with a ceramic ball bearing, the air suspension bearing is more energy-saving, has higher rotating speed and low maintenance cost, can reduce the energy consumption of the compressor, and improves the pneumatic performance of the compressor.

Further, the casing 1 is provided with a cooling liquid inlet 161 and a cooling liquid outlet 162, which are used for cooling the inside of the compressor, and the height of the cooling liquid outlet 162 is less than or equal to the height of the first air gap of the stator and the rotor of the motor 2, so that the cooling medium is prevented from being completely evaporated to cause liquid impact, and the running problem of the motor 2 caused by liquid impact is avoided. The first air gap height here refers to the air gap height between the rotor and the stator of the motor 2 near the coolant inlet. The outer side wall of the stator of the motor 2 is provided with a cooling groove 211, the cooling groove 211 is of an annular structure, cooling liquid enters the inside of the shell 1 from the cooling liquid inlet 161, flows through the cooling groove 211 to cool the stator of the motor 2, then enters a cavity of the motor 2, flows through a gap between the stator and the rotor of the motor 2 to cool the rotor, further cools the driving shaft 3 and the bearing, and finally flows out of the shell 1 from the cooling liquid outlet 162.

The outside of casing 1 has still arranged terminal box 12, be equipped with the wiring pin in the terminal box 12, through to the external power source is inserted to the wiring pin, for the motor provides the electric energy, and the motor begins operation work.

A first protruding portion 31 is arranged on one side, away from the motor 2, of the first end shaft, a second protruding portion 32 is arranged on one side, away from the motor 2, of the second end shaft, and in this embodiment, the first thrust bearing 51 is sleeved on the outer side of the first protruding portion 31; in another embodiment, the second protruding portion 32 is sleeved with a second thrust bearing, and the number of the thrust bearings can be set by a user according to actual needs, which is not particularly limited herein.

The first pump body further comprises a first impeller 61 and a first diffuser 71, and a wheel disc of the first impeller 61 and the first diffuser 71 are positioned on the same plane; the second pump body further comprises a second impeller 62 and a second diffuser 72, and a wheel disc of the second impeller 62 and the second diffuser 72 are positioned on the same plane; the sides of the first impeller 61 and the second impeller 62 facing the motor 2 are sealed by labyrinth seals, so as to prevent air leakage loss in the pump body. The high-speed rotating impeller works on the gas to enable the gas to obtain energy, and when the gas flows out of the impeller, the high-speed gas has high speed, and the speed of the high-speed gas is reduced and the pressure is increased after the high-speed gas flows through the diffuser.

A first set screw 81 is further arranged in the first pump body, and the first set screw 81 passes through the first impeller 61 from the first side of the first impeller 61 and is in threaded connection with the first end shaft; a second set screw 82 is further disposed in the second pump body, and the second set screw 82 passes through the second impeller 62 from the first side of the second impeller 62, and is screwed to the second end shaft.

Referring to fig. 1 and 2, the centrifugal compressor further includes a first scroll 91 and a second scroll 92, the first pump body is disposed in the first scroll 91, the second pump body is disposed in the second scroll 92, and the first scroll 91 and the second scroll 92 are disposed opposite to each other.

The centrifugal compressor further comprises a communicating pipe 10, and the first pump body and the second pump body are communicated through the communicating pipe 10. The gas compressed by the first pump body flows into the second pump body from the outlet of the first scroll 91 through the communication pipe 10, is compressed again, and is discharged to the outside of the compressor.

The communicating pipe 10 is further provided with a gas supplementing pipe 11, and the direction of fluid in the gas supplementing pipe 11 is the same as the direction of fluid at the outlet of the first volute 91, so that efficiency loss caused by two fluid impacts is reduced, efficiency of refrigeration cycle of the compressor is improved, refrigerating capacity is improved, and exhaust temperature of the compressor is reduced. A temperature/pressure sensor 13 is also provided at the outlet of the communication pipe 10 and the second scroll 92 for monitoring the temperature or pressure of the gas flowing through the pipe. The centrifugal compressor further comprises a first cavity and a second cavity, the first cavity is fixedly connected with the first volute 91 through a first flange, the first cavity comprises a first inlet 171, and gas enters the first pump body from the first inlet 171; the second cavity is fixedly connected with the second volute 92 through a second flange, the second cavity comprises a second inlet 172, the gas compressed by the first pump body enters the second pump body through the second inlet 172 for recompression, and the compressed gas is discharged out of the compressor through a first outlet 173. An inlet guide vane is arranged in the first cavity and used for preventing the compressor from surging, and the inlet guide vane reasonably sets the gas flow entering the first pump body by setting the opening and closing angle of the guide vane through an inlet guide vane actuator 14; in other embodiments, the second cavity is also provided with inlet guide vanes, and the number of the inlet guide vanes can be set by a user according to actual requirements, which is not specifically limited herein.

A base is further arranged on one side, close to the ground, of the shell 1, so that the compressor can be fixed on the ground conveniently. In this embodiment, the number of bases of the compressor is 4. In other embodiments, the number of the bases may be set according to practical needs, without limitation.

The working process of the centrifugal compressor in this embodiment is as follows: the inlet guide vane is opened according to a preset opening and closing angle, the low-temperature low-pressure gas enters the first pump body from the gas first inlet 171, the high-temperature high-pressure gas is discharged after being compressed by the first impeller 61 rotating at a high speed, the high-temperature high-pressure gas flows into the volute runner after being reduced in speed and pressurized by the first diffuser 71, then the high-pressure gas discharged from the outlet of the first volute 91 enters the second pump body through the communication pipeline 10 to be further compressed and pressurized, the pressurizing process is the same as the compressing process in the first pump body, the secondarily-pressurized high-pressure gas is discharged out of the compressor through the exhaust outlet 173 and enters the refrigeration cycle assembly to be subjected to refrigeration cycle.

the invention provides a centrifugal compressor which adopts an air suspension bearing, and compared with the centrifugal compressor adopting a magnetic suspension bearing and a ceramic bearing, the centrifugal compressor has the advantages of low energy consumption, more energy saving and low maintenance cost; the whole structure of the air suspension compressor is more compact, the length of the compressor bearing is obviously shortened, and the occupied space of the compressor is small; the centrifugal compressor adopting the air suspension bearing has higher rotating speed which can reach more than 20 ten thousand revolutions per minute, and can improve the pneumatic performance of the centrifugal compressor.

The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.

Claims

1. A centrifugal compressor, comprising:

a housing including a cavity;

The motor is arranged in the cavity;

A driving shaft including a main shaft connected to a rotor of the motor, and a first end shaft and a second end shaft extending out of both sides of the motor in an axial direction;

the first pump body and the first bearing assembly are hermetically fixed on the first end shaft through the first bearing assembly;

The second pump body and the second bearing assembly are hermetically fixed on the second end shaft through the second bearing assembly;

The first bearing assembly and the second bearing assembly each comprise an air bearing.

2. The centrifugal compressor of claim 1, wherein the first bearing assembly comprises a first thrust bearing and a first radial bearing, the first thrust bearing and the first radial bearing are sleeved on a first side and a second side of the first end shaft, respectively, and the first radial bearing is fixedly connected with the first end of the housing.

3. The centrifugal compressor of claim 2, wherein the second bearing assembly comprises a second thrust bearing and a second radial bearing, the second thrust bearing and the second radial bearing are sleeved on a first side and a second side of the second end shaft, respectively, and the second radial bearing is fixedly connected with a second end of the housing;

4. A centrifugal compressor according to claim 3, wherein a first boss is provided on a side of the first end shaft facing away from the motor, a second boss is provided on a side of the second end shaft facing away from the motor, the first thrust bearing is sleeved outside the first boss, and the second thrust bearing is sleeved outside the second boss.

5. The centrifugal compressor of claim 4, further comprising a first impeller and a first diffuser within the first pump body, the disk of the first impeller being in a same plane as the first diffuser;

The second pump body further comprises a second impeller and a second diffuser, and the wheel disc of the second impeller and the second diffuser are positioned on the same plane.

6. The centrifugal compressor of claim 5, wherein a first set screw is further provided in the first pump body, the first set screw passing through the first impeller from a first side of the first impeller, the first set screw being threadably coupled to the first end shaft;

The second pump body is internally provided with a second set screw, and the second set screw penetrates through the second impeller from the first side of the second impeller and is in threaded connection with the second end shaft.

7. The centrifugal compressor of claim 6, further comprising a first volute and a second volute, the first pump body disposed in the first volute, the second pump body disposed in the second volute, the first and second volutes disposed opposite one another.

8. The centrifugal compressor according to claim 7, wherein a side of said first impeller and said second impeller facing said motor are each sealed by a labyrinth seal.

9. The centrifugal compressor according to claim 7, further comprising a communication pipe through which the first pump body and the second pump body communicate.

10. The centrifugal compressor according to claim 9, wherein a gas supplementing pipe is further provided on the communication pipe, and a fluid direction in the gas supplementing pipe is the same as a fluid direction of an outlet of the first scroll casing.

11. The centrifugal compressor of claim 7, further comprising a first cavity and a second cavity, the first cavity being fixedly connected to the first volute by a first flange; the second cavity is fixedly connected with the second volute through a second flange plate.