Centrifugal compressor and control method

Abstract

A centrifugal compressor and a control method. The centrifugal compressor comprises: a first bearing, which is arranged in a radial bearing chamber and comprises a first bearing housing, a first wave foil and a first top foil; and a second bearing (15), which is radially opposite a rotor, wherein in the radial direction of the centrifugal compressor, a radial gap between the second bearing (15) and the rotor minus a radial gap between the first top foil and the rotor is less than the thickness of the first top foil.

Description

Centrifugal compressor and control method

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410847522.9, filed on June 27, 2024, and entitled “Centrifugal compressor and control method”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of centrifugal compressor bearing, in particular to a centrifugal compressor and a control method. BACKGROUND

[0004] Gas dynamic bearing is one of the forms of sliding bearing, which has similar structure and working principle to liquid sliding bearing, but uses gas (mostly air) as lubricating medium, has extremely low friction, does not need lubricating liquid, has a wide range of use speed and temperature, and is widely used in high-speed rotating machinery field, for example, used in cooperation with the rotor in the centrifugal compressor. Foil gas dynamic bearing is a kind of gas dynamic bearing, due to its complex structural characteristics and working environment, foil gas dynamic bearing has the problem of easy failure.

[0005] SUMMARY

[0006] The following is a summary of the subject matter of the detailed description herein. This summary is not intended to limit the scope of the claims.

[0007] One purpose of the present application is to provide a centrifugal compressor which can protect the first top foil and the first wave foil and can predict the service life of the first bearing in advance.

[0008] Another purpose of the present application is to provide a control method for the above-mentioned centrifugal compressor.

[0009] A centrifugal compressor, comprising: a housing, a rotor, a stator, a first bearing and a second bearing, the housing is provided with a radial bearing chamber; the rotor and the stator are arranged in the housing; the first bearing is arranged in the radial bearing chamber, the first bearing comprises: a first bearing seat, a first wave foil and a first top foil, the first wave foil is located between the first top foil and the first bearing seat and elastically pushes against the first top foil, the first top foil is opposite to the rotor in the radial direction; the second bearing is arranged in the housing, the second bearing is opposite to the rotor in the radial direction; wherein in the radial direction of the centrifugal compressor, the radial gap between the second bearing and the rotor minus the radial gap between the first top foil and the rotor is less than the thickness of the first top foil.

[0010] According to the centrifugal compressor provided by the embodiment of the present application, by arranging the first bearing and the second bearing, and limiting the size relationship between the radial gap between the second bearing and the rotor, the radial gap between the first top foil and the rotor, and the thickness of the first top foil, the first top foil, the first wave foil and the like can be well protected when the rotor is impacted due to instability, the reliability and the service life of the first bearing can be improved, and the working performance and stability of the rotor can be improved. In addition, whether the first top foil of the first bearing needs to be replaced can be identified in advance, after the first bearing is worn due to long-term frequent start-stop and long-term abnormal working conditions, the service life of the first bearing can be effectively predicted, and the first bearing, the sealing component and the like can be effectively protected, and the maintenance cost can be reduced.

[0011] According to some embodiments of the present application, the centrifugal compressor further comprises: an impeller arranged on the rotor, and the shell further comprises: a wheel cover, and the impeller is provided with a wheel cover seal on one side opposite to the wheel cover and a wheel back seal on the other side.

[0012] According to some embodiments of the present application, the radial gap between the second bearing and the rotor is smaller than the radial gap between the wheel cover seal and the impeller.

[0013] According to some embodiments of the present application, the radial gap between the second bearing and the rotor is also smaller than the radial gap between the wheel back seal and the rotor.

[0014] According to some embodiments of the present application, the rotor is provided with a rotor shaft sleeve, and the radial gap between the rotor shaft sleeve and the second bearing, minus the radial gap between the first top foil and the rotor shaft sleeve, is smaller than the thickness of the first top foil.

[0015] According to some embodiments of the present application, the radial gap between the second bearing and the rotor shaft sleeve is smaller than the radial gap between the wheel back seal and the rotor.

[0016] According to some embodiments of the present application, the radial gap between the second bearing and the rotor shaft sleeve is smaller than the radial gap between the wheel cover seal and the impeller.

[0017] According to some embodiments of the present application, when the first top foil is in an extreme compression state or after being worn, the radial gap between the first top foil and the rotor is greater than or equal to the radial gap between the second bearing and the rotor.

[0018] According to some embodiments of the present application, the second bearing and the wheel back seal are connected through a first potting layer.

[0019] According to some embodiments of the present application, the first potting layer is provided with a first sensor, which is adapted to detect the radial pressure borne by the second bearing and trigger when the rotor presses against the second bearing.

[0020] According to some embodiments of the present application, the centrifugal compressor further comprises a third bearing and a thrust disc, the casing further has an axial bearing chamber, the third bearing is arranged in the axial bearing chamber, the thrust disc is connected to the rotor, the third bearing comprises a second bearing seat, a second wave foil and a second top foil, the second wave foil is located between the second top foil and the second bearing seat and elastically pushes against the second top foil, the second top foil is axially opposite to the thrust disc, and the third bearing is axially opposite to the thrust disc; wherein in the axial direction of the centrifugal compressor, the axial gap between the second bearing and the rotor, minus the axial gap between the second top foil and the thrust disc, is less than the thickness of the second top foil.

[0021] According to some embodiments of the present application, the rotor is provided with a rotor sleeve, and in the axial direction of the centrifugal compressor, the axial gap between the second bearing and the rotor sleeve, minus the axial gap between the second top foil and the thrust disc, is less than the thickness of the second top foil.

[0022] According to some embodiments of the present application, the axial gap between the third bearing and the rotor is less than the axial gap between the shroud seal and the impeller, and the axial gap between the third bearing and the rotor is also less than the axial gap between the back seal and the thrust disc.

[0023] According to some embodiments of the present application, when the second top foil is in an extreme compression state or after wear, the axial gap between the second bearing and the rotor is less than or equal to the axial gap between the second top foil and the thrust disc.

[0024] According to some embodiments of the present application, the second bearing and the back seal are further provided with a second potting layer, and the second potting layer is integrally potted with the first potting layer.

[0025] According to some embodiments of the present application, the second potting layer is provided with a second sensor, which is adapted to detect the axial pressure borne by the second bearing and trigger when the thrust disc presses against the second bearing.

[0026] According to some embodiments of the present application, the rotor comprises a primary rotor and a secondary rotor, the radial bearing chamber comprises a primary radial bearing chamber corresponding to the primary rotor and a secondary radial bearing chamber corresponding to the secondary rotor, one of the first bearings is arranged in the primary radial bearing chamber, and one of the first bearings is arranged in the secondary radial bearing chamber, the axial bearing chamber comprises a primary axial bearing chamber corresponding to the primary rotor and a secondary axial bearing chamber corresponding to the secondary rotor, one of the third bearings is arranged in the primary axial bearing chamber, and one of the third bearings is arranged in the secondary axial bearing chamber, the two third bearings are arranged on the axial two sides of the thrust disc, one end of the primary rotor is provided with one of the second bearings, and the other end of the secondary rotor is provided with one of the second bearings.

[0027] According to some embodiments of the present application, the primary axial bearing chamber and the secondary axial bearing chamber are arranged on the axial two sides of the housing, the thrust disc comprises a first thrust disc and a second thrust disc, the primary rotor is provided with the first thrust disc, the secondary rotor is provided with the second thrust disc, or the primary axial bearing chamber and the secondary axial bearing chamber are arranged on the same axial side of the housing, and the two third bearings are arranged on the axial two sides of the thrust disc.

[0028] According to some embodiments of the present application, the first bearing is configured as a radial dynamic pressure bearing, the second bearing is configured as a ball bearing, and the third bearing is configured as an axial dynamic pressure bearing.

[0029] A control method comprises: acquiring a trigger duration and a trigger number of a first sensor and a second sensor; if the trigger duration exceeds a duration threshold or the trigger number exceeds a first number threshold, a fault is reported and the machine is stopped.

[0030] According to some embodiments of the present application, the duration threshold is 30s-60s, and the first number threshold is 8-12.

[0031] According to some embodiments of the present application, the control method further comprises: acquiring a trigger number of a first sensor and a second sensor; if the trigger number of the first sensor exceeds a second number threshold within a first time threshold, a first bearing damage warning is reported and the machine is urgently stopped; and if the trigger number of the second sensor exceeds the second number threshold within the first time threshold, a third bearing damage warning is reported and the machine is urgently stopped.

[0032] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0033] FIG. 1 is a side view of a centrifugal compressor according to some embodiments of the present application;

[0034] Fig. 2 is a cross-sectional view of Fig. 1 along A-A;

[0035] Fig. 3 is an enlarged view of B in Fig. 2;

[0036] Fig. 4 is an enlarged view of C in Fig. 2;

[0037] Fig. 5 is an enlarged view of D in Fig. 2;

[0038] Fig. 6 is a schematic view of a second bearing cooperating with a first sensor, a second sensor, etc. according to some embodiments of the present application;

[0039] Fig. 7 is a flow chart of a control method according to some embodiments of the present application. DETAILED DESCRIPTION

[0040] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which like or similar elements or features are denoted by like reference characters, and in which the embodiments of the present application described are by way of illustration only. The embodiments described below are examples for the practical realization of the present application and are not to be construed as limiting the present application.

[0041] A centrifugal compressor 1 and a control method according to embodiments of the present application are described below with reference to Figs. 1-7.

[0042] As shown in Figs. 1 and 2, a centrifugal compressor 1 according to a first aspect embodiment of the present application, the centrifugal compressor 1 comprises a casing 11, a rotor, a stator 13, a first bearing, and a second bearing 15.

[0043] The casing 11 is provided with a radial bearing chamber; the rotor and the stator 13 are both arranged in the casing 11; the first bearing is arranged in the radial bearing chamber, the first bearing comprising a first bearing seat, a first wave foil, and a first top foil, the first wave foil being located between the first top foil and the first bearing seat and elastically pushing against the first top foil, the first top foil being opposite to the rotor in a radial direction; the second bearing 15 is arranged in the casing 11, the second bearing 15 being opposite to the rotor in the radial direction; in the radial direction of the centrifugal compressor 1, a radial gap between the second bearing 15 and the rotor, minus a radial gap between the first top foil and the rotor, is less than a thickness of the first top foil.

[0044] The stator 13 and the rotor are arranged in the shell 11 in the application, and the stator 13 and the rotor can jointly cooperate to realize the centrifugal compressor 1 having a compressed gas function; the first bearing can be arranged in the radial bearing chamber of the shell 11 to realize installation and fixation at a preset position of the shell 11, in the first bearing, the first bearing seat can provide a mounting position for part of other components (such as a first wave foil and a first top foil) in the first bearing, and can support, fix and protect part of other components in the first bearing, the first wave foil and the first top foil can be arranged on the radial inner side of the first bearing seat, the first top foil is sleeved on the outer periphery of the rotor and is spaced apart from the rotor in the radial direction, supports the radial suspension of the rotor, the first wave foil is arranged between the first top foil and the first bearing seat, the first wave foil can be an elastic wave structure and has good deformation performance, which can improve the carrying capacity and performance stability; the second bearing 15 can be arranged in the shell 11 and opposite to the rotor in the radial direction, and the second bearing 15 is used for supporting and positioning the rotor.

[0045] The present application inventors noticed that in the related art, the first bearing for supporting the radial suspension of the rotor, when the rotor loses stability due to sudden power failure or strong external impact, the rotor will hit the first top foil of the first bearing, forcing the first top foil to deform outward, extruding the first wave foil located on the outer side of the first top foil, and the first wave foil will be deformed greatly or even collapsed due to the impact of the rotor, resulting in failure of the first bearing.

[0046] For the above phenomenon, the present application inventors found that the position relationship between the first top foil and the first wave foil can be used, the first top foil is the component that first contacts the rotor among the first top foil and the first wave foil, therefore, the first top foil can be protected by the second bearing 15 to avoid continuous deformation or damage of the first top foil, and the first wave foil can also be protected.

[0047] Based on this, the present application further makes the radial gap between the second bearing 15 and the rotor minus the radial gap between the first top foil and the rotor less than the thickness of the first top foil.

[0048] The second bearing 15 in the application can be arranged in sequence with the first bearing in the axial direction, and the rotor is located between the second bearing 15 and the inner periphery of the first top foil. After long-term operation of the first top foil, the first top foil may have a certain degree of wear, so that the radial gap between the first top foil and the rotor becomes shorter. By arranging the second bearing 15 in the radial direction of the centrifugal compressor 1, the radial gap between the second bearing 15 and the rotor, minus the radial gap between the first top foil and the rotor, is less than the thickness of the first top foil. Therefore, when the first top foil reaches a certain degree of wear after long-term operation, the second bearing 15 can contact the rotor, so that it can be identified in advance whether the first top foil of the first bearing needs to be replaced, and the first top foil can be prevented from continuing to wear and being seriously worn or even worn out, so that the normal and reliable work of the first top foil can be ensured. In addition, when the rotor moves outward in the radial direction due to instability (such as sudden power failure or external impact), the second bearing 15 can also support and protect the first top foil and the first wave foil between the rotor and the first top foil, so that the deformation of the first top foil and the first wave foil is within the design range, and the first wave foil located outside the first top foil cannot be deformed excessively and cannot recover elasticity due to the impact of the rotor.

[0049] According to the centrifugal compressor 1 of the application, by arranging the first bearing and the second bearing 15 and limiting the size relationship between the radial gap between the second bearing 15 and the rotor, the radial gap between the first top foil and the rotor, and the thickness of the first top foil, the first top foil, the first wave foil and the like can be well protected when the rotor is impacted due to instability, the reliability and service life of the first bearing can be improved, and the working performance and stability of the rotor can be improved. In addition, it can be identified in advance whether the first top foil of the first bearing needs to be replaced. After the first bearing is worn due to long-term frequent start-stop and long-term abnormal working conditions, the service life of the first bearing can be effectively predicted, and the first bearing, sealing components and other parts can be effectively protected, thereby reducing maintenance costs.

[0050] As shown in FIG. 2, according to some embodiments of the application, the centrifugal compressor 1 further comprises: an impeller 16 arranged on the rotor, and the shell 11 further comprises: a cover, the impeller 16 is arranged on one side of the cover opposite to the cover, and the other side is arranged with a back seal 18.

[0051] The impeller 16 is arranged on the rotor, and the rotation of the rotor can drive the impeller 16 to rotate to achieve gas flow guiding and compression; the cover is used for supporting, connecting and sealing the impeller 16, and helps to maintain the balance of the rotor and reduce vibration caused by uneven mass distribution; wherein the impeller 16 is arranged on one side of the cover opposite to the cover, and the other side of the impeller 16 away from the cover is arranged with a back seal 18. The cover seal 17 and the back seal 18 can improve the structural air tightness and enhance the anti-gas and liquid leakage effect, so as to improve the compression efficiency of the centrifugal compressor 1.

[0052] As shown in FIG. 2, according to some embodiments of the present application, the radial gap between the second bearing 15 and the rotor is smaller than the radial gap between the shroud seal 17 and the impeller 16.

[0053] When the radial gap between the shroud seal 17 and the impeller 16 is smaller than or equal to the radial gap between the second bearing 15 and the rotor, the gas leakage prevention performance is poor, and the overall structure stability is reduced. Therefore, by limiting the size relationship between the radial gap between the shroud seal 17 and the impeller 16 and the radial gap between the second bearing 15 and the rotor within the above range, the radial gap between the shroud seal 17 and the impeller 16 is small, which helps to optimize the sealing performance, improve the gas leakage prevention performance, improve the work efficiency, and improve the rotor operation stability.

[0054] As shown in FIG. 2, according to some embodiments of the present application, the radial gap between the second bearing 15 and the rotor is also smaller than the radial gap between the back seal 18 and the rotor.

[0055] When the radial gap between the back seal 18 and the rotor is smaller than or equal to the radial gap between the second bearing 15 and the rotor, the gas leakage prevention performance is poor, and the overall structure stability is reduced. Therefore, by limiting the size relationship between the radial gap between the back seal 18 and the rotor and the radial gap between the second bearing 15 and the rotor within the above range, the radial gap between the back seal 18 and the rotor is small, which helps to optimize the sealing performance, improve the gas leakage prevention performance, improve the work efficiency, and improve the rotor operation stability.

[0056] As shown in FIG. 5, according to some embodiments of the present application, the rotor is provided with a rotor sleeve 25, and the radial gap between the rotor sleeve 25 and the second bearing 15, minus the radial gap between the first top foil and the rotor sleeve 25, is smaller than the thickness of the first top foil.

[0057] At least part of the outer periphery of the rotor can be sleeved with a rotor sleeve 25, and the rotor sleeve 25 is located between the rotor and the second bearing 15. In this way, the rotor sleeve 25 can reduce the friction between the rotor and the second bearing 15, save energy loss, and play a good protection role.

[0058] The radial gap between the rotor sleeve 25 and the second bearing 15, minus the radial gap between the first top foil and the rotor sleeve 25, is less than the thickness of the first top foil. Similarly, the rotor sleeve 25 is located inside the second bearing 15 and the first top foil, which can have a certain wear after long-term operation, so that the radial gap between the first top foil and the rotor sleeve 25 becomes shorter, and by setting the radial gap between the rotor sleeve 25 and the second bearing 15, minus the radial gap between the first top foil and the rotor sleeve 25, to be less than the thickness of the first top foil, so that when the first top foil reaches a certain degree of wear after long-term operation, the second bearing 15 can be in contact with the rotor sleeve 25, thereby the first top foil of the first bearing can be identified in advance whether it needs to be replaced, and the first top foil can be prevented from continuing to wear and being seriously worn or even worn out, and the normal and reliable work of the first top foil can be ensured.

[0059] As shown in FIG. 5, according to some embodiments of the present application, the radial gap between the second bearing 15 and the rotor sleeve 25 is less than the radial gap between the back seal 18 and the rotor.

[0060] When the radial gap between the back seal 18 and the rotor is less than or equal to the radial gap between the second bearing 15 and the rotor sleeve 25, it will result in poor gas and liquid leakage prevention performance and reduce the overall structure operation stability, therefore, by limiting the size relationship of the radial gap between the back seal 18 and the rotor and the radial gap between the second bearing 15 and the rotor sleeve 25 within the above range, the radial gap between the back seal 18 and the rotor is small, which helps to optimize the sealing performance, improve the gas leakage prevention performance, improve the work efficiency, and improve the rotor operation stability.

[0061] As shown in FIG. 5, according to some embodiments of the present application, the radial gap between the second bearing 15 and the rotor sleeve 25 is less than the radial gap between the cover seal 17 and the impeller 16.

[0062] When the radial gap between the cover seal 17 and the impeller 16 is less than or equal to the radial gap between the second bearing 15 and the rotor sleeve 25, it will result in poor gas and liquid leakage prevention performance and reduce the overall structure operation stability, therefore, by limiting the size relationship of the radial gap between the cover seal 17 and the impeller 16 and the radial gap between the second bearing 15 and the rotor sleeve 25 within the above range, the radial gap between the cover seal 17 and the impeller 16 is small, which helps to optimize the sealing performance, improve the gas leakage prevention performance, improve the work efficiency, and improve the rotor operation stability.

[0063] As shown in FIG. 2, according to some embodiments of the present application, the radial gap between the first top foil and the rotor is greater than or equal to the radial gap between the second bearing 15 and the rotor when the first top foil is in an extreme compression state or after wear.

[0064] In the case that the first top foil is not worn or slightly worn, the first top foil normally suspends the rotor, the outer circumferential surface of the rotor does not contact the second bearing 15 which is radially spaced, and the first top foil, the first wave foil and the rotor are normally and safely operated; when the rotor is suddenly moved radially due to power failure or external impact, etc., causing the first top foil to be in an extreme compression state, and when the first top foil is worn after long-term operation, etc., the distance between the rotor and the first top foil is shortened, the radial gap between the first top foil and the rotor is greater than or equal to the radial gap between the second bearing 15 and the rotor, and the distance between the second bearing 15 and the rotor in the radial direction is equal to or shorter than the distance between the first top foil and the rotor in the radial direction; in this case, when the rotor moves outward in the radial direction, the rotor will first contact the second bearing 15 with a shorter distance, so that the second bearing 15 can support and protect between the rotor and the first top foil and the first wave foil, can protect the deformation of the first top foil and the first wave foil within the design range, and protect the first wave foil located outside the first top foil from being excessively deformed by the impact of the rotor and unable to recover elasticity.

[0065] As shown in FIGS. 3-5, according to some embodiments of the present application, the second bearing 15 and the back seal 18 are connected through the first potting layer 19.

[0066] The first potting layer 19 can be an insulating potting adhesive, which can specifically use materials such as epoxy resin, silicone rubber, polyurethane, etc. with good electrical insulation and sealing properties. The first potting layer 19 is located between the second bearing 15 and the back seal 18, which can separate the second bearing 15 and the back seal 18. The first potting layer 19 can have a good buffering effect, which can reduce the damage degree of the second bearing 15 when the second bearing 15 is impacted by the rotor during protection, thereby improving the service life of the second bearing 15.

[0067] It can be understood that the insulating potting adhesive is initially in a liquid state and begins to solidify after being filled, so it can also play a role in fixing the second bearing 15 and improve the installation stability of the second bearing 15.

[0068] It should be pointed out that the second bearing 15 and the back seal 18 in the present application can also be connected through other processes, for example, they can be connected through injection molding.

[0069] As shown in FIGS. 3, 5 and 6, according to some embodiments of the present application, the first potting layer 19 is provided with a first sensor 20, which is adapted to detect the radial pressure borne by the second bearing 15 and triggered when the rotor presses against the second bearing 15.

[0070] Specifically, the first sensor 20 can be a piezoresistive sensor, and the first sensor 20 is adapted to detect the radial pressure borne by the second bearing 15 and trigger when the rotor presses against the second bearing 15. When the first bearing is subjected to a severe impact of the rotor under abnormal working conditions, the first wave foil of the first bearing is compressed, the first top foil is deformed radially outward, the rotor impacts on the second bearing 15, at this time the first sensor 20 monitors the radial pressure and can send a fault signal to stop the centrifugal compressor 1, thereby providing good protection for the first bearing; and when the first top foil is worn to a certain extent due to start-stop wear, the radial gap between the first top foil and the rotor becomes larger, and the rotor is prone to continuously pressing against the second bearing 15, and the first sensor 20 will continuously monitor the pressure, including monitoring the pressure after shutdown (the weight of the rotor after shutdown), which indicates that the first top foil is severely worn due to start-stop wear. Therefore, the first sensor 20 can also serve as a reminder to replace the first top foil, and can monitor and intelligently diagnose the first top foil, the first wave foil and the second bearing 15 to achieve predictive maintenance, which can prevent further damage to the rotor, impeller 16 and back seal 18 and other parts caused by high-speed operation of the damaged first top foil, improve the working reliability of the centrifugal compressor 1, and save maintenance costs.

[0071] It can be understood that by arranging the first sensor 20 on the outer side of the first potting layer 19 of the second bearing 15, on the one hand, the first sensor 20 can be fixed, and the installation stability of the first sensor 20 can be improved; on the other hand, the first potting layer 19 can also provide good insulation and sealing protection, and can protect the first sensor 20 and the wire harness of the first sensor 20 from damage, thereby improving the working reliability, safety and durability of the first sensor 20.

[0072] It should be noted that the first sensor 20 can be configured as a plurality of sensors, and preferably, as shown in FIG. 6, the first sensor 20 is configured as three sensors equally spaced in the circumferential direction of the second bearing 15, so as to increase the detection range of the first sensor 20 and improve the detection accuracy.

[0073] As shown in FIGS. 2 and 5, according to some embodiments of the present application, the centrifugal compressor 1 further comprises a third bearing and a thrust disc 22, and the shell 11 further has an axial bearing chamber 112, the third bearing is arranged in the axial bearing chamber 112, and the thrust disc 22 is connected to the rotor. The third bearing comprises a second bearing seat, a second wave foil and a second top foil, the second wave foil is located between the second top foil and the second bearing seat and elastically pushes against the second top foil, the second top foil is axially opposite to the thrust disc 22, and the third bearing is axially opposite to the thrust disc 22.

[0074] Wherein, in the axial direction of the centrifugal compressor 1, the axial gap between the second bearing 15 and the rotor, minus the axial gap between the second top foil and the thrust disc 22, is less than the thickness of the second top foil.

[0075] Specifically, in the present application, the thrust disc 22 is connected to the rotor to bear the axial force generated by the rotor due to gas compression, so as to improve the stability of the rotor in operation; the third bearing can be arranged in the axial bearing chamber 112 of the casing 11, in which the second bearing seat can provide a mounting position for part of other components (such as the second wave foil and the second top foil) in the axial dynamic pressure bearing, and can support, fix and protect part of other components in the axial dynamic pressure bearing, the second wave foil and the second top foil can be arranged at one end of the second bearing seat in the axial direction, the second top foil and the thrust disc 22 are opposite in the axial direction and are spaced apart by a certain distance, supporting the axial suspension of the thrust disc 22 and the rotor, and the second wave foil is arranged between the second top foil and the second bearing seat. The second wave foil can be of an elastic wave structure and has good deformation performance, which can improve the carrying capacity and performance stability.

[0076] Similarly, the second top foil in the present application can be worn after a long period of operation, so that the axial gap between the second top foil and the thrust disc 22 becomes shorter, and by arranging the axial gap between the second bearing 15 and the rotor in the axial direction of the centrifugal compressor 1, the axial gap between the second top foil and the thrust disc 22, minus the thickness of the second top foil, so that when the second top foil is worn to a certain degree after a long period of operation, the second bearing 15 can be in contact with the rotor, so that the replacement period of the second top foil of the third bearing can be identified in advance, and the second top foil can be prevented from being further worn to a serious or even worn-out state, so as to ensure the normal and reliable operation of the second top foil. In addition, when the rotor moves in the axial direction due to instability, the second bearing 15 can also support and protect the second top foil, the second wave foil and the like, so as to protect the deformation of the second top foil and the second wave foil within the designed range, and protect the second wave foil on the side of the second top foil from being excessively deformed due to the impact of the rotor and losing elasticity. In this way, the reliability and service life of the second top foil and the second wave foil can be improved, the working performance and stability of the rotor, the impeller 16, the back seal 18, the cover seal 17 and other components can be improved, and the maintenance cost can be saved.

[0077] As shown in FIGS. 2 and 5, according to some embodiments of the present application, a rotor sleeve 25 is arranged on the rotor, and in the axial direction of the centrifugal compressor 1, the axial gap between the second bearing 15 and the rotor sleeve 25, minus the axial gap between the second top foil and the thrust disc 22, is less than the thickness of the second top foil.

[0078] Specifically, in the case that the rotor shaft sleeve 25 is arranged on the rotor, the rotor shaft sleeve 25 is located between the rotor and the second bearing 15, and by arranging an axial gap between the second bearing 15 and the rotor shaft sleeve 25 in the axial direction of the centrifugal compressor 1, the axial gap between the second top foil and the thrust disc 22 is less than the thickness of the second top foil, so that when the second top foil is worn to a certain degree after long-term operation, the second bearing 15 can be in contact with the rotor shaft sleeve 25, thereby the replacement period of the second top foil of the third bearing can be identified in advance, and the second top foil can be prevented from being further worn to a serious wear or even worn out, and the normal and reliable operation of the second top foil can be ensured.

[0079] As shown in FIG. 2, according to some embodiments of the present application, the axial gap between the third bearing and the rotor is less than the axial gap between the shroud seal 17 and the impeller 16, and the axial gap between the third bearing and the rotor is also less than the axial gap between the back seal 18 and the thrust disc 22.

[0080] Specifically, when the axial gap between the shroud seal 17 and the impeller 16 and the axial gap between the back seal 18 and the thrust disc 22 are less than or equal to the axial gap between the third bearing and the rotor, it will result in poor gas leakage prevention performance and reduce the overall structural operation stability. Therefore, by limiting the size relationship of the axial gap between the shroud seal 17 and the impeller 16, the axial gap between the back seal 18 and the thrust disc 22, and the axial gap between the third bearing and the rotor within the above range, the axial gap between the shroud seal 17 and the impeller 16 and the axial gap between the back seal 18 and the thrust disc 22 are small, which helps to optimize the sealing performance, improve the gas leakage prevention performance, improve the work efficiency, and improve the rotor operation stability.

[0081] As shown in FIG. 2, according to some embodiments of the present application, the axial gap between the second bearing 15 and the rotor is less than or equal to the axial gap between the second top foil and the thrust disc 22 when the second top foil is in the limit compression state or after being worn.

[0082] Specifically, in the case that the second top foil is not worn or slightly worn, the second top foil normally suspends the thrust disc and the rotor, and the rotor does not contact the second bearing 15 in the axial direction, and the second top foil, the second wave foil and the rotor are all normally and safely working; when the rotor suddenly loses stability due to power failure or external impact and moves in the axial direction, causing the second top foil to be in an extreme compression state, and when the second top foil is worn after long-term operation, the distance between the thrust disc and the second top foil is shortened, the axial gap between the second top foil and the thrust disc is greater than or equal to the axial gap between the second bearing 15 and the rotor, and the axial distance between the second bearing 15 and the rotor is equal to or shorter than the axial distance between the second top foil and the thrust disc. In this case, when the rotor moves in the axial direction, the rotor will first contact the second bearing 15, so that the second bearing 15 can well protect the second top foil and the second wave foil, and can protect the deformation of the second top foil and the second wave foil within the design range, and protect the second wave foil located outside the second top foil from being excessively deformed and losing elasticity due to the impact of the rotor.

[0083] As shown in FIG. 3, according to some embodiments of the present application, the second bearing 15 and the back seal 18 are further provided with a second filling layer 23, and the second filling layer 23 is integrally filled with the first filling layer 19.

[0084] Specifically, the second filling layer 23 can be an insulating filling glue, and can be made of materials such as epoxy resin, silicone rubber and polyurethane, which have good electrical insulation and sealing properties. The second filling layer 23 is located between the second bearing 15 and the back seal 18, and can separate the second bearing 15 and the back seal 18. The second filling layer 23 can have a good buffering effect, and can reduce the damage degree of the second bearing 15 when the second bearing 15 is impacted by the rotor during protection, thereby prolonging the service life of the second bearing 15.

[0085] It should be noted that the second filling layer 23 is integrally filled with the first filling layer 19. The second filling layer 23 can extend in the radial direction, and the second filling layer 23 is located in the radial area between the second bearing 15 and the back seal 18. The first filling layer 19 can extend in the axial direction, and the first filling layer 19 is located in the axial area between the second bearing 15 and the back seal 18. In this way, the radial and axial areas between the second bearing 15 and the back seal 18 are filled with insulating filling glue, which can further improve the stability of the installation of the second bearing 15.

[0086] As shown in FIG. 4 and FIG. 6, according to some embodiments of the present application, the second filling layer 23 is provided with a second sensor 24, and the second sensor 24 is adapted to detect the axial pressure borne by the second bearing 15 and is triggered when the thrust disc 22 presses against the second bearing 15.

[0087] Specifically, the second sensor 24 can be one or more, the second sensor 24 is configured as a piezoresistive sensor, which is suitable for detecting the axial pressure borne by the second bearing 15 and triggering when the thrust disc 22 presses against the second bearing 15. When the third bearing is subjected to the severe impact of the rotor and the thrust disc 22 under abnormal working conditions, the second wave foil of the third bearing is compressed, the second top foil is deformed, the thrust disc 22 impacts on the second bearing 15, the second sensor 24 monitors the axial pressure and can send a fault signal to stop the centrifugal compressor 1, thereby providing good protection for the third bearing; and when the second top foil of the third bearing is worn to a certain extent due to start-stop, the axial gap between the second top foil and the thrust disc 22 becomes larger, and the rotor is prone to continuously pressing against the second bearing 15. The second sensor 24 will correspondingly monitor the pressure continuously, and the continuous pressure can still be monitored after restarting, indicating that the second top foil is severely worn due to start-stop. Therefore, the second sensor 24 can also remind the replacement of the second top foil, and can monitor and intelligently diagnose the second top foil, the second wave foil and the second bearing 15 to achieve predictive maintenance, which can avoid further damage to the thrust disc 22, the rotor, the impeller 16 and the back seal 18 and other parts caused by high-speed operation after the second top foil is damaged, and can improve the working reliability of the centrifugal compressor 1 and save maintenance costs.

[0088] Similarly, by arranging the second sensor 24 in the second potting layer 23, on the one hand, the second sensor 24 can be fixed, and the installation stability of the second sensor 24 can be improved; on the other hand, the second potting layer 23 can also provide good insulation and sealing protection, which can protect the second sensor 24 and the wire harness of the second sensor 24 from damage, and can improve the working reliability, safety and durability of the first sensor 20.

[0089] As shown in FIG. 2, according to some embodiments of the present application, the rotor includes a first-stage rotor 12a and a second-stage rotor 12b, the radial bearing chamber includes a first-stage radial bearing chamber 111a corresponding to the first-stage rotor 12a and a second-stage radial bearing chamber 111b corresponding to the second-stage rotor 12b, a first bearing is arranged in the first-stage radial bearing chamber 111a, and a first bearing is arranged in the second-stage radial bearing chamber 111b; the axial bearing chamber 112 includes a first-stage axial bearing chamber corresponding to the first-stage rotor 12a and a second-stage axial bearing chamber corresponding to the second-stage rotor 12b, a third bearing is arranged in the first-stage axial bearing chamber, and a third bearing is arranged in the second-stage axial bearing chamber; one end of the first-stage rotor 12a is provided with a second bearing 15, and the other end of the second-stage rotor 12b is provided with a second bearing 15.

[0090] Specifically, the first-stage rotor 12a and the second-stage rotor 12b can be coaxially arranged and connected, the first-stage radial bearing chamber 111a corresponds to the first-stage rotor 12a, the second-stage radial bearing chamber 111b corresponds to the second-stage rotor 12b, the first-stage radial bearing chamber 111a and the second-stage radial bearing chamber 111b are each provided with a first bearing to cooperate with the first-stage rotor 12a and the second-stage rotor 12b respectively, so as to improve the working performance and the running stability of the rotor; the first-stage axial bearing chamber corresponds to the first-stage rotor 12a, the second-stage axial bearing chamber corresponds to the second-stage rotor 12b, the first-stage axial bearing chamber and the second-stage axial bearing chamber are each provided with a third bearing to cooperate with the first-stage rotor 12a and the second-stage rotor 12b respectively, so as to improve the working performance and the running stability of the rotor.

[0091] It should be noted that the first bearing and the third bearing can be adjacently arranged on the rotor, and the first bearing and the third bearing can be installed in the same bearing chamber, which is used as the radial bearing chamber and the axial bearing chamber 112, so as to improve the integration of the first bearing and the third bearing. For example, as shown in FIG. 2, the first-stage radial bearing chamber 111a and the axial bearing chamber 112 can be the same bearing chamber.

[0092] In addition, in some specific embodiments of the present application, the first bearing arranged in the first-stage radial bearing chamber 111a corresponds to a first-stage first bearing seat 141a, a first-stage first top foil 143a and a first-stage first wave foil 142a; the first bearing arranged in the second-stage radial bearing chamber 111b corresponds to a second-stage first bearing seat 141b, a second-stage first top foil 143b and a second-stage first wave foil 142b.

[0093] As shown in FIG. 2, according to some embodiments of the present application, the first and second axial bearing chambers are located on the axial two sides of the shell 11, the thrust disc 22 comprises: a first thrust disc and a second thrust disc, the first rotor 12a is provided with the first thrust disc, the second rotor 12b is provided with the second thrust disc, or the first and second axial bearing chambers are located on the axial same side of the shell 11, and two third bearings are located on the axial two sides of the thrust disc 22. Specifically, the thrust disc 22, the first and second axial bearing chambers, etc. have various arrangements. In some embodiments, the first and second rotors 12a and 12b are both provided with the thrust disc 22, and correspond to the first and second thrust discs respectively, the first and second axial bearing chambers can be located on the axial two sides of the shell 11 respectively, so that the two third bearings are located on the axial two sides of the shell 11 respectively to cooperate with the first and second thrust discs respectively to optimize the working performance and balance of the rotors; in other embodiments, only one of the first and second rotors 12a and 12b is provided with the thrust disc 22, i.e. the thrust disc 22 is provided on the first or second rotor 12a or 12b, the first and second axial bearing chambers can be located on the axial same side of the shell 11, and the two third bearings are located on the axial same side of the shell 11, and at the same time, the two third bearings are located on the axial two sides of the thrust disc 22 to cooperate with the thrust disc 22 to optimize the working performance and balance of the rotors.

[0094] In addition, it should be noted that in the third bearing according to the present application, the second bearing seat, the second wave foil, the second top foil, etc. are arranged on the axial two sides of the thrust disc 22, in each third bearing, the second bearing seat comprises the first side second bearing seat 211c and the second side second bearing seat 211d located on the two sides of the thrust disc 22, the second wave foil comprises the first side second wave foil 212c and the second side second wave foil 212d located on the two sides of the thrust disc 22, and the second top foil comprises the first side second top foil 213c and the second side second top foil 213d located on the two sides of the thrust disc 22.

[0095] As shown in FIG. 2, according to some embodiments of the present application, the first bearing is configured as a radial dynamic pressure bearing, the second bearing 15 is configured as a ball bearing, and the third bearing is configured as an axial dynamic pressure bearing.

[0096] Specifically, the radial dynamic pressure bearing uses gas as a lubricating medium, the first bearing is configured as a radial dynamic pressure bearing, radial suspension support of the rotor can be achieved, which helps the rotor to operate at low friction and high speed, saves energy consumption, and improves the working performance, stability and service life of the rotor; similarly, the third bearing is configured as an axial dynamic pressure bearing, axial suspension support of the rotor can be achieved, which helps the rotor to operate at low friction and high speed, saves energy consumption, and improves the working performance, stability and service life of the rotor; the second bearing 15 is configured as a ball bearing, and the second bearing 15 can be an angular contact ball bearing. Since the ball bearing has the advantages of high load capacity, low friction coefficient, high precision, long service life and easy maintenance, the second bearing 15 can be matched with the rotor by configuring the second bearing 15 as a ball bearing, which can improve the working reliability and service life of the rotor, and also can protect the first bearing and the third bearing when the rotor is impacted in harsh working conditions.

[0097] As shown in FIG. 7, according to the control method of the second embodiment of the present application, the control method is suitable for the centrifugal compressor described in any of the above embodiments, and the control method comprises: obtaining the triggering time length and the triggering times of the first sensor 20 and the second sensor 24; if the triggering time length exceeds the time length threshold or the triggering times exceed the first times threshold, a fault is reported and the machine is stopped.

[0098] Specifically, according to the control method of the second aspect of the present application, whether to report a fault and stop the machine can be determined according to whether the triggering time length of the first sensor 20 and the second sensor 24 exceeds the time length threshold, or whether the triggering times of the first sensor 20 and the second sensor 24 exceed the first times threshold. When the triggering time length exceeds the time length threshold or the triggering times exceed the first times threshold, a fault is reported and the machine is stopped, so that maintenance and replacement can be performed in time, and the working performance, reliability and safety of the centrifugal compressor 1 are improved.

[0099] It should be noted that the triggering time length can be a single triggering time length, and when the single triggering time length exceeds the time length threshold, a fault can be reported and the machine can be stopped. The triggering time length can also be the sum of multiple triggering time lengths, and when the sum of the multiple triggering time lengths exceeds the time length threshold, a fault can be reported and the machine can be stopped.

[0100] Correspondingly, the time length threshold can be single, compared with the single triggering time length, or the time length threshold can be cumulative, compared with the sum of the multiple triggering time lengths, to determine whether to report a fault and stop the machine.

[0101] As shown in FIG. 7, according to some embodiments of the present application, the time length threshold is 30s-60s, and the first times threshold is 8-12 times.

[0102] Specifically, setting the time threshold too small or too large, or setting the first number threshold too small or too large, will all cause inaccurate determination of reporting faults and stopping, affecting the accuracy of reporting. By setting the time threshold and the first number threshold within the above range, the time threshold and the first number threshold have reasonable range values. For example, the time threshold can be 40s or 50s, and the first number threshold can be set to 9 or 10. In this way, by comparing the triggering time and the triggering number of the first sensor 20 and the second sensor 24 with the time threshold and the first number threshold, the accuracy of fault alarm can be improved to facilitate maintenance.

[0103] As shown in FIG. 7, according to some embodiments of the present application, the control method further comprises: obtaining the triggering number of the first sensor 20 and the second sensor 24; if the triggering number of the first sensor 20 exceeds the second number threshold within the first time threshold, reporting a first bearing damage alarm and emergency shutdown; if the triggering number of the second sensor 24 exceeds the second number threshold within the first time threshold, reporting a third bearing damage alarm and emergency shutdown.

[0104] Specifically, when the first sensor 20 and the second sensor 24 are triggered, it may be that the first top foil and the second top foil are deformed due to severe working conditions, causing the rotor to press against the second bearing 15 to trigger, or it may be that the first bearing and the third bearing are severely worn, causing the first sensor 20 and the second sensor 24 to trigger in succession. Therefore, the customer needs to be prompted to replace the first bearing and the third bearing (the friction life of the first bearing and the third bearing has begun to approach the end), and the difference between the two cases can be determined according to the first time threshold and the second number threshold. The specific determination is: if the triggering number of the first sensor 20 exceeds the second number threshold within the first time threshold, reporting a first bearing damage alarm and emergency shutdown; if the triggering number of the second sensor 24 exceeds the second number threshold within the first time threshold, reporting a third bearing damage alarm and emergency shutdown.

[0105] It can be understood that the triggering of both the first sensor 20 and the second sensor 24 indicates that both the first bearing and the third bearing are abnormal; only the triggering of the first sensor 20 indicates that only the first bearing is abnormal, while the third bearing is normal; only the triggering of the second sensor 24 indicates that only the third bearing is abnormal, while the first bearing is normal. Through the different triggering conditions of the first sensor 20 and the second sensor 24, it can be accurately known which part of the bearing is abnormal, which can effectively improve the convenience and efficiency of maintenance.

[0106] In addition, in some specific embodiments of the present application, the first time threshold is 30 min to 90 min, the second number threshold is 8 to 12, and the second number threshold is greater than or equal to the first number threshold. If the first time threshold is too small or too large, or the second number threshold is too small or too large, the determination of reporting the first bearing and the third bearing damage alarm will be inaccurate, and the targeted maintenance and replacement will be inconvenient. By setting the first time threshold and the second number threshold in the above range, the first time threshold and the second number threshold have reasonable range values. For example, the first time threshold can be 30 min or 60 min, and the second number threshold can be 11 or 12. It can be understood that the second number threshold is greater than or equal to the first number threshold. For example, if the second number threshold is 11, the first number threshold is at most 11. In this way, by comparing the triggering time and the number of triggers of the first sensor 20 and the second sensor 24 with the first time threshold and the second number threshold, the alarm accuracy can be improved, and the maintenance and replacement convenience and efficiency can be improved.

[0107] It should be noted that the above-mentioned second number threshold is compared with the number of triggers of a single second bearing 15, and the first number threshold is compared with the cumulative number of triggers of the two second bearings 15 at both ends of the rotor.

[0108] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0109] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A centrifugal compressor, wherein, include: A housing, wherein the housing is provided with a radial bearing chamber; A rotor and a stator, both of which are disposed in the housing; The first bearing is disposed in the radial bearing chamber and includes: a first bearing housing, a first corrugated foil, and a first top foil. The first corrugated foil is located between the first top foil and the first bearing housing and elastically pushes against the first top foil. The first top foil is radially opposite to the rotor. A second bearing is disposed in the housing and is radially opposite to the rotor; wherein In the radial direction of the centrifugal compressor, the radial clearance between the second bearing and the rotor, minus the radial clearance between the first top foil and the rotor, is less than the thickness of the first top foil.

2. The centrifugal compressor according to claim 1, wherein, The centrifugal compressor further includes an impeller disposed on the rotor, and the housing further includes a wheel cover, wherein a wheel cover seal is disposed on one side of the impeller opposite to the wheel cover, and a wheel back seal is disposed on the other side.

3. The centrifugal compressor according to claim 2, wherein, The radial clearance between the second bearing and the rotor is smaller than the radial clearance between the wheel cover seal and the impeller.

4. The centrifugal compressor according to claim 3, wherein, The radial clearance between the second bearing and the rotor is also smaller than the radial clearance between the wheel back seal and the rotor.

5. The centrifugal compressor according to any one of claims 2-4, wherein, The rotor is provided with a rotor bushing, and the radial clearance between the rotor bushing and the second bearing, minus the radial clearance between the first top foil and the rotor bushing, is less than the thickness of the first top foil.

6. The centrifugal compressor according to claim 5, wherein, The radial clearance between the second bearing and the rotor bushing is smaller than the radial clearance between the wheel back seal and the rotor.

7. The centrifugal compressor according to claim 5, wherein, The radial clearance between the second bearing and the rotor bushing is smaller than the radial clearance between the wheel cover seal and the impeller.

8. The centrifugal compressor according to any one of claims 2-7, wherein, After the first top foil is under extreme compression or wear, the radial clearance between the first top foil and the rotor is greater than or equal to the radial clearance between the second bearing and the rotor.

9. The centrifugal compressor according to any one of claims 2-8, wherein, The second bearing is connected to the wheel back seal through the first potting layer.

10. The centrifugal compressor according to claim 9, wherein, A first sensor is provided within the first potting layer. The first sensor is adapted to detect the radial pressure borne by the second bearing and is triggered when the rotor presses against the second bearing.

11. The centrifugal compressor according to claim 9, wherein, Also includes: The housing also has an axial bearing chamber, the third bearing is disposed in the axial bearing chamber, the thrust plate is connected to the rotor, and the third bearing includes: a second bearing seat, a second corrugated foil and a second top foil, the second corrugated foil is located between the second top foil and the second bearing seat and elastically pushes against the second top foil, the second top foil and the thrust plate are axially opposite each other, and the third bearing and the thrust plate are axially opposite each other; in In the axial direction of the centrifugal compressor, the axial clearance between the second bearing and the rotor, minus the axial clearance between the second top foil and the thrust plate, is less than the thickness of the second top foil.

12. The centrifugal compressor according to claim 11, wherein, The rotor is provided with a rotor bushing. In the axial direction of the centrifugal compressor, the axial clearance between the second bearing and the rotor bushing, minus the axial clearance between the second top foil and the thrust plate, is less than the thickness of the second top foil.

13. The centrifugal compressor according to claim 11, wherein, The axial clearance between the third bearing and the rotor is less than the axial clearance between the wheel cover seal and the impeller, and the axial clearance between the third bearing and the rotor is also less than the axial clearance between the wheel back seal and the thrust plate.

14. The centrifugal compressor according to claim 11, wherein, When the second top foil is under extreme compression or wear, the axial clearance between the second bearing and the rotor is less than or equal to the axial clearance between the second top foil and the thrust plate.

15. The centrifugal compressor according to claim 11, wherein, The second bearing and the wheel back seal are further provided with a second potting layer, which is integrally potted with the first potting layer.

16. The centrifugal compressor according to claim 15, wherein, A second sensor is provided within the second potting layer. The second sensor is adapted to detect the axial pressure borne by the second bearing and is triggered when the thrust plate presses against the second bearing.

17. The centrifugal compressor according to claim 11, wherein, The rotor includes a primary rotor and a secondary rotor. The radial bearing chamber includes a primary radial bearing chamber corresponding to the primary rotor and a secondary radial bearing chamber corresponding to the secondary rotor. A first bearing is disposed in the primary radial bearing chamber and a first bearing is disposed in the secondary radial bearing chamber. The axial bearing chamber includes a primary axial bearing chamber corresponding to the primary rotor and a secondary axial bearing chamber corresponding to the secondary rotor. A third bearing is disposed in the primary axial bearing chamber and a third bearing is disposed in the secondary axial bearing chamber. A second bearing is disposed at one end of the primary rotor and at the other end of the secondary rotor.

18. The centrifugal compressor according to claim 17, wherein, The primary axial bearing chamber and the secondary axial bearing chamber are located on opposite sides of the housing along the axial direction. The thrust plate includes a first thrust plate and a second thrust plate. The primary rotor is provided with the first thrust plate, and the secondary rotor is provided with the second thrust plate. Alternatively, the primary axial bearing chamber and the secondary axial bearing chamber are located on the same side of the housing along the axial direction, and the two third bearings are located on opposite sides of the thrust plate along the axial direction.

19. The centrifugal compressor according to any one of claims 1-18, wherein, The first bearing is a radial dynamic pressure bearing, the second bearing is a ball bearing, and the third bearing is an axial dynamic pressure bearing.

20. A control method applicable to the centrifugal compressor according to any one of claims 1-19, wherein, include: Obtain the trigger duration and trigger count of the first and second sensors; If the trigger duration exceeds the duration threshold or the number of triggers exceeds the first trigger threshold, a fault will be reported and the system will be shut down.

21. The control method according to claim 20, wherein, The duration threshold is 30s to 60s, and the first number threshold is 8 to 12 times.

22. The control method according to claim 21, wherein, The control method further includes: Obtain the trigger counts of the first and second sensors; If the number of triggers of the first sensor exceeds the second threshold within the first time threshold, an alarm for damage to the first bearing will be issued and the machine will be shut down immediately. If the number of triggers of the second sensor exceeds the second threshold within the first time threshold, a third bearing damage alarm will be reported, and the machine will be shut down immediately.

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