Axial hydrodynamic bearing, centrifugal compressor, and control method

Abstract

An axial hydrodynamic bearing, a centrifugal compressor, and a control method. The axial hydrodynamic bearing comprises: a thrust disk (11) and a bearing seat (12); a bump foil (13) and a top foil (14); and a protective ring (15), the protective ring (15) being provided on the bearing seat (12). In the same axial direction, the difference between the axial gap between the protective ring (15) and the thrust disk (11) and the axial gap between the top foil (14) and the thrust disk (11) is less than the thickness of the top foil (14).

Description

Axial dynamic pressure bearing, centrifugal compressor and control method

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202410847414.1, filed on June 27, 2024, entitled “Axial dynamic pressure bearing, 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 an axial dynamic pressure bearing, a centrifugal compressor and a control method. BACKGROUND

[0004] Gas dynamic pressure bearing is a kind of sliding bearing, its structure and working principle are similar to liquid sliding bearing, the difference is that gas (mostly air) is used as lubricating medium, it has very low friction, no need for lubricating liquid, wide speed range and wide temperature range, etc., so it is widely used in high-speed rotating machinery field, for example, used with rotor in centrifugal compressor. Foil gas dynamic pressure bearing is a kind of gas dynamic pressure bearing, due to its complex structure characteristics and working environment, etc., foil gas dynamic pressure 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 an axial dynamic pressure bearing which can protect top foil, wave foil and the like, and can identify whether the top foil needs to be replaced in advance.

[0008] Another purpose of the present application is to provide a centrifugal compressor having the above axial dynamic pressure bearing.

[0009] Still another purpose of the present application is to provide a control method.

[0010] An axial dynamic pressure bearing is arranged on a rotor, the axial dynamic pressure bearing comprising: a thrust disc, a bearing seat, a wave foil, a top foil and a protective ring; the wave foil is located between the top foil and the bearing seat and elastically pushes against the top foil, the top foil and the thrust disc are opposite in the axial direction; the protective ring is arranged on the bearing seat; wherein the axial gap between the protective ring and the thrust disc in the same axial direction, minus the axial gap between the top foil and the thrust disc, is less than the thickness of the top foil.

[0011] According to the axial dynamic pressure bearing of the embodiment of the present application, by setting the protection ring, limiting the axial gap between the protection ring and the thrust disc, the axial gap between the top foil and the thrust disc, and the thickness of the top foil, the top foil, the wave foil and the like can be well protected when the rotor and the thrust disc are impacted by instability, the reliability and the service life of the top foil and the wave foil can be improved, the working performance and the stability of the rotor can be improved, and the top foil can be identified in advance whether it needs to be replaced, the axial dynamic pressure bearing with the service life close to the end can be determined in time, so that the customer can know in advance and replace the axial dynamic pressure bearing, and the downtime and the maintenance cost can be reduced.

[0012] According to some embodiments of the present application, the axial dynamic pressure bearing further comprises a lead wire bundle, one end of the lead wire bundle is connected with the protection ring, the lead wire bundle is wrapped with an insulating layer, the other end of the lead wire bundle is led out and formed into a detection circuit, and the detection circuit is adapted to be turned on when the thrust disc presses against the protection ring.

[0013] According to some embodiments of the present application, the protection ring is configured as a graphite ring.

[0014] According to some embodiments of the present application, the bearing seat is provided with a mounting groove, and at least part of the protection ring is arranged in the mounting groove.

[0015] According to some embodiments of the present application, the cross-sectional area of the protection ring gradually decreases in the direction towards the thrust disc.

[0016] According to some embodiments of the present application, a filling layer is arranged between the protection ring and the mounting groove to provide buffer protection.

[0017] According to some embodiments of the present application, when the top foil is in an extreme compression state or after wear, the axial gap between the protection ring and the thrust disc is less than or equal to the axial gap between the top foil and the thrust disc.

[0018] A centrifugal compressor comprises a shell, a stator, a rotor and an axial dynamic pressure bearing, the shell has an axial bearing chamber; the stator and the rotor are arranged in the shell; the axial dynamic pressure bearing is configured as the axial dynamic pressure bearing of any one of the above embodiments, the axial dynamic pressure bearing is arranged in the axial bearing chamber, and the thrust disc is connected with the rotor.

[0019] According to some embodiments of the present application, the centrifugal compressor further comprises an impeller arranged on the thrust disc, the shell further comprises a wheel cover, 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, the axial gap between the protection ring and the thrust disc is less than the axial gap between the wheel cover seal and the impeller, and the axial gap between the protection ring and the thrust disc is also less than the axial gap between the wheel back seal and the thrust disc.

[0020] According to some embodiments of the present application, the rotor comprises a primary rotor and a secondary rotor, the axial bearing chamber comprises a primary bearing chamber corresponding to the primary rotor and a secondary bearing chamber corresponding to the secondary rotor, a primary bearing is arranged in the primary bearing chamber, a secondary bearing is arranged in the secondary bearing chamber, at least one of the primary bearing and the secondary bearing is configured as the axial dynamic pressure bearing, and the primary bearing and the secondary bearing are located on the axial two sides of the thrust disc.

[0021] According to some embodiments of the present application, the primary bearing chamber and the secondary bearing chamber are located on the axial two sides, the thrust disc comprises a first thrust disc corresponding to the primary rotor and a second thrust disc corresponding to the secondary rotor, the primary bearing is matched with the first thrust disc, the secondary bearing is matched with the second thrust disc, or the thrust disc is arranged on the primary rotor or the secondary rotor, the primary bearing chamber and the secondary bearing chamber are located on the axial same side, and the primary bearing and the secondary bearing are located on the axial two sides of the thrust disc.

[0022] According to some embodiments of the present application, the primary bearing and the secondary bearing are both configured as the axial dynamic pressure bearing, and the centrifugal compressor further comprises a detection module having a detection circuit, the detection circuit comprises a first loop and a second loop, the first loop is a loop formed by connecting the outgoing wire harness of the primary bearing with the shell, the second loop is a loop formed by connecting the outgoing wire harness of the secondary bearing with the shell, any loop is conducted, and the detection module issues an alarm.

[0023] A control method comprises: acquiring the conduction duration and the conduction times of a detection circuit; if the conduction duration exceeds a duration threshold or the conduction times exceeds a first times threshold, a fault is reported and the machine is stopped.

[0024] According to some embodiments of the present application, the duration threshold is 30s-60s, and the first times threshold is 8-12 times.

[0025] According to some embodiments of the present application, the control method further comprises: acquiring the conduction times of a first loop and a second loop, the first loop is a loop formed by connecting the outgoing wire harness of the primary bearing with the shell, and the second loop is a loop formed by connecting the outgoing wire harness of the secondary bearing with the shell; within a first time threshold, if the conduction times of the first loop exceeds a second times threshold, a primary bearing damage alarm is reported and the machine is urgently stopped; within the first time threshold, if the conduction times of the second loop exceeds the second times threshold, a secondary bearing damage alarm is reported and the machine is urgently stopped.

[0026] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and / or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 is an axial dynamic pressure bearing isometric view according to some embodiments of the application;

[0028] Fig. 2 is an axial dynamic pressure bearing front view according to some embodiments of the application;

[0029] Fig. 3 is a section view of Fig. 2 along A-A;

[0030] Fig. 4 is a partial structural section view of an axial dynamic pressure bearing;

[0031] Fig. 5 is a control method flowchart according to some embodiments of the application. DETAILED DESCRIPTION

[0032] Embodiments of the application are described in detail below with reference to the attached drawing figures, wherein the same or like designations identify similar elements or elements with similar functions throughout the several views. The following detailed description includes embodiments that describe examples of the application, and is intended to be illustrative, and not limiting of the application.

[0033] An axial dynamic pressure bearing 1, a centrifugal compressor and a control method according to embodiments of the application are described below with reference to Figs. 1-5.

[0034] As shown in Figs. 1 and 2, the axial dynamic pressure bearing 1 according to a first aspect embodiment of the application, the axial dynamic pressure bearing 1 is arranged on a rotor, the axial dynamic pressure bearing 1 comprises: a thrust disc 11, a bearing seat 12, a wave foil 13, a top foil 14 and a guard ring 15, the wave foil 13 is located between the top foil 14 and the bearing seat 12, and is elastically pushed against the top foil 14, the top foil 14 and the thrust disc 11 are opposite in the axial direction; the guard ring 15 is arranged on the bearing seat 12; wherein in the same axial direction, the axial gap between the guard ring 15 and the thrust disc 11, minus the axial gap between the top foil 14 and the thrust disc 11, is less than the thickness of the top foil 14.

[0035] The thrust disc 11 in the application is used to bear the axial force of the rotor due to gas compression, so as to improve the stability of the rotor in operation; the bearing seat 12 can provide a mounting position for part of other components (such as the wave foil 13 and the top foil 14) in the axial dynamic pressure bearing 1, and can support, fix and protect part of other components in the axial dynamic pressure bearing 1; the wave foil 13 and the top foil 14 can be arranged at one end of the bearing seat 12 in the axial direction, the top foil 14 is opposite to the thrust disc 11 in the axial direction and is spaced apart by a certain distance, the thrust disc 11 is supported and suspended in the axial direction by the top foil 14, the wave foil 13 is arranged between the top foil 14 and the bearing seat 12, the wave foil 13 can be a flexible wave structure and has good deformation performance, so as to improve the carrying capacity and performance stability; the protective ring 15 can be arranged at the same end of the bearing seat 12 in the axial direction with the wave foil 13 and the top foil 14, the protective ring 15 is opposite to the thrust disc 11 in the axial direction, and the protective ring 15 and the top foil 14 are arranged in sequence in the radial direction. It can be understood that the protective ring 15 can be arranged on the radial inner side of the top foil 14, but is not limited to this, and in some embodiments, the protective ring 15 can also be arranged on the radial outer side of the top foil 14, so as to simplify the assembly environment of the outer periphery of the bearing seat 12 in the radial direction. The arrangement of the protective ring 15 in the radial direction of the bearing seat 12 can be designed according to specific requirements.

[0036] The inventors of the application find that in the related art, when the rotor and the thrust disc 11 lose stability due to sudden power failure or strong external impact, the rotor and the thrust disc 11 will hit the top foil 14 of the axial dynamic pressure bearing 1, forcing the top foil 14 to deform outwardly, extruding the wave foil 13 on one side of the top foil 14, and the wave foil 13 will be deformed or even collapsed due to the impact of the rotor and the thrust disc 11, resulting in failure of the axial dynamic pressure bearing 1.

[0037] For the above phenomenon, the inventors of the application find that the position relationship between the top foil 14 and the wave foil 13 can be used, the top foil 14 in the top foil 14 and the wave foil 13 is the component first contacted with the thrust disc 11 and the rotor, so that the protective ring 15 for protecting the top foil 14 is added to avoid continuous deformation or damage of the top foil 14, and the wave foil 13 can also be protected.

[0038] Based on this, the application further makes the axial gap between the protective ring 15 and the thrust disc 11 minus the axial gap between the top foil 14 and the thrust disc 11 less than the thickness of the top foil 14.

[0039] The top foil 14 in the application can have certain wear after long-term operation, so that the axial gap between the top foil 14 and the thrust disc 11 becomes longer, and the axial gap between the protective ring 15 and the thrust disc 11 in the same axial direction is set, and the axial gap between the top foil 14 and the thrust disc 11 is less than the thickness of the top foil 14, so that when the top foil 14 reaches a certain degree of wear after long-term operation, the protective ring 15 can be in contact with the rotor, thereby the top foil 14 can be identified whether it needs to be replaced in advance, the top foil 14 can be prevented from continuing to wear and being seriously worn or even worn out, and the normal and reliable work of the top foil 14 can be ensured. In addition, when the rotor and the thrust disc 11 move in the axial direction due to instability (such as sudden power failure or external impact), the thrust disc 11 will first contact the protective ring 15, so that the protective ring 15 can well protect the top foil 14 and the wave foil 13, and can protect the top foil 14 and the wave foil 13 from being deformed beyond the design range, and protect the wave foil 13 on the side of the top foil 14 from being deformed too much by the impact of the rotor and losing elasticity.

[0040] It should be noted that the above-mentioned same axial direction can be selected as the axial direction of the specific equipment to which the axial dynamic pressure bearing 1 is applied, for example, the axial dynamic pressure bearing 1 is applied to a centrifugal compressor, and then the axial direction of the centrifugal compressor is selected as the reference.

[0041] According to the axial dynamic pressure bearing 1 of the application, by setting the protective ring 15 and limiting the size relationship between the axial gap between the protective ring 15 and the thrust disc 11, the axial gap between the top foil 14 and the thrust disc 11, and the thickness of the top foil 14, the top foil 14 and the wave foil 13 can be well protected when the rotor and the thrust disc 11 are impacted due to instability, the reliability and service life of the top foil 14 and the wave foil 13 can be improved, the working performance and stability of the rotor can be improved, and the top foil 14 can be identified whether it needs to be replaced in advance, so that the customer can predict and replace the axial dynamic pressure bearing 1 in advance, reduce downtime and maintenance cost.

[0042] As shown in FIGS. 1 and 3, according to some embodiments of the application, the axial dynamic pressure bearing 1 further comprises a lead wire bundle 16, one end of the lead wire bundle 16 is connected with the protective ring 15, the lead wire bundle 16 is wrapped with an insulating layer 17, and the other end of the lead wire bundle 16 is led out and formed into a detection circuit, and the detection circuit is adapted to be turned on when the thrust disc 11 presses against the protective ring 15.

[0043] The protective ring 15 can be configured of a material having electrical conductivity. One end of the lead wire bundle 16 is connected to the protective ring 15, and the other end is led out and formed into a detection circuit. When the thrust disc 11 presses against the protective ring 15, the detection circuit is turned on, so that it can be determined whether the axial dynamic pressure bearing 1 is normally running, and the wear condition of the axial dynamic pressure bearing 1 after a long time of running, and the like, by the principle of contact conduction. For example, when the power supply is suddenly interrupted, or the impact of the top foil 14 and the wave foil 13 is caused by severe working conditions to dissipate energy, and the like, the thrust disc 11 can press against the protective ring 15 for a short time, and the detection circuit is turned on for a short time. When the top foil 14 needs to be maintained and replaced due to severe wear, the thrust disc 11 can press against the protective ring 15 for a long time and continuously, and the detection circuit is turned on continuously. By setting the lead wire bundle 16 in cooperation with the protective ring 15, the top foil 14, the wave foil 13, and the protective ring 15 can be monitored and intelligently diagnosed, so as to realize predictive maintenance, avoid affecting the use of the axial dynamic pressure bearing 1 after the axial dynamic pressure bearing 1 is damaged, and improve the working reliability and safety.

[0044] It should be noted that a wire bundle channel suitable for accommodating the lead wire bundle 16 can be formed in the bearing seat 12, so as to improve the stability and working safety of the lead wire bundle 16.

[0045] Preferably, the wire bundle channel extends along the radial direction of the bearing seat 12, so as to protect the lead wire bundle 16 from interfering with other components (such as the top foil 14 and the wave foil 13) in the axial direction, and improve the working reliability.

[0046] In addition, in some embodiments of the present application, the insulating layer 17 can be a plastic piece (such as polyethylene) or a rubber piece, and the like. The insulating layer 17 can ensure that the lead wire bundle 16 and the protective ring 15 have good insulation with other components, so as to improve the working safety.

[0047] In some other embodiments of the present application, the other end of the lead wire bundle 16 is led out and provided with a through piece having a sealing function, so as to further improve the insulation and sealing, and further improve the working safety, on the basis of realizing that the led-out part can be formed into a detection circuit.

[0048] As shown in FIGS. 3 and 4, according to some embodiments of the present application, the protective ring 15 is configured as a graphite ring.

[0049] The protective ring 15 can be configured as a graphite ring. The graphite material has good electrical conductivity, which can ensure that the protective ring 15 and the thrust disc 11 can determine the running failure and the damage degree of the top foil 14 by the contact conduction function. At the same time, the graphite material has good lubrication effect and wear resistance, so that the thrust disc 11 will not be damaged when pressing against the graphite, thereby playing a good buffering and protection role, and helping to prolong the service life of the protective ring 15 and save maintenance costs.

[0050] It should be noted that the protective ring 15 can be but is not limited to a graphite ring, and in some embodiments, the protective ring 15 can also be replaced by other conductive and wear-resistant materials, such as graphene, conductive carbon black, and carbon fibers, etc.

[0051] As shown in FIGS. 3 and 4, according to some embodiments of the present application, the bearing seat 12 is provided with a mounting groove, and at least part of the protective ring 15 is arranged in the mounting groove.

[0052] The bearing seat 12 can be formed with a mounting groove at one end in the axial direction, the mounting groove is open towards the direction close to the thrust disc 11, at least part of the protective ring 15 can be arranged in the mounting groove, the shape of the mounting groove can match the shape of at least part of the protective ring 15, by arranging the mounting groove, a good limiting effect can be achieved, the installation stability of the protective ring 15 on the bearing seat 12 can be improved, and the working reliability of the protective ring 15 can be improved.

[0053] As shown in FIGS. 3 and 4, according to some embodiments of the present application, the cross-sectional area of the protective ring 15 gradually decreases in the direction towards the thrust disc 11.

[0054] The protective ring 15 has a certain length in the axial direction, the cross-sectional area of the protective ring 15 gradually decreases in the direction towards the thrust disc 11, the shape of the mounting groove is correspondingly configured to gradually decrease in the cross-sectional area in the direction towards the thrust disc 11, so that at least part of the inner or outer circumferential surface of the protective ring 15 is arranged obliquely, and at least part of the inner wall of the mounting groove is correspondingly arranged obliquely, the part of the mounting groove matched with the protective ring 15 can play a good limiting effect in the axial and radial directions, and the movement of the protective ring 15 relative to the bearing seat 12 can be limited, so that the connection stability between the protective ring 15 and the bearing seat 12 can be improved, and the anti-disengagement performance and working reliability of the protective ring 15 can be improved; on the other hand, the protective ring 15 can be easily assembled into the mounting groove.

[0055] It should be noted that the oblique arrangement of at least part of the protective ring 15 has various cases, for example, the protective ring 15 can be configured with an oblique outer circumferential surface and an axial inner circumferential surface, the protective ring 15 can also be configured with an oblique inner circumferential surface and an axial outer circumferential surface, and the protective ring 15 can also be configured with oblique inner and outer circumferential surfaces.

[0056] Preferably, the protective ring 15 is configured with oblique inner and outer circumferential surfaces, and the cross-sectional shape of the protective ring 15 in the circumferential direction is an isosceles trapezoid, so as to enhance the anti-disengagement effect.

[0057] As shown in FIG. 4, according to some embodiments of the present application, a filling layer 18 is arranged between the protective ring 15 and the mounting groove, so as to provide buffering protection.

[0058] The potting layer 18 can be insulating potting glue, and can be specifically epoxy resin, silicone rubber, polyurethane, or other materials with good electrical insulation and sealing properties. The potting layer 18 is located between the protective ring 15 and the mounting groove, and can separate the protective ring 15 from the bearing seat 12. In a first aspect, the potting layer 18 can provide good cushioning. When the protective ring 15 is impacted by the thrust disc 11 during protection, the potting layer 18 can appropriately cushion the impact, so as to avoid serious damage to the protective ring 15. In a second aspect, the potting layer 18 can also provide good insulation and sealing protection. The potting layer 18 can ensure that the protective ring 15 has good insulation performance with the bearing seat 12 and the shell of the centrifugal compressor, and can play a protective role to improve safety. In addition, the potting layer 18 can also protect the lead bundle 16 connected to the protective ring 15 from damage, and can improve the reliability and durability of the lead bundle 16. It can be understood that the insulating potting glue is initially in a liquid state, and solidifies after being filled. Therefore, the potting layer 18 can also fix the protective ring 15 and the lead bundle 16, and can improve the installation stability of the protective ring 15 and the lead bundle 16.

[0059] In addition, in some embodiments of the present application, the potting layer 18 includes a first ring segment, a second ring segment, and a third ring segment connected in sequence. The first ring segment and the third ring segment are respectively located at the inner and outer circumferences of the protective ring 15, and the second ring segment is located at one end of the protective ring 15 axially away from the thrust disc 11. In this way, the areas of the protective ring 15 opposite to the bearing seat 12 are filled with insulating potting glue, so as to ensure that the protective ring 15 is completely insulated from the bearing seat 12.

[0060] It should be noted that the mounting groove has sufficient space for filling insulating potting glue in terms of width and depth, and the opening size of the mounting groove is designed to allow the protective ring 15 to smoothly enter the mounting groove at least partially.

[0061] As shown in FIGS. 1-3, according to some embodiments of the present application, the axial gap between the protective ring 15 and the thrust disc 11 is less than or equal to the axial gap between the top foil 14 and the thrust disc 11 when the top foil 14 is in an extreme compression state or after being worn out.

[0062] When the top foil 14 is not worn or slightly worn, the top foil 14 normally suspends and supports the thrust disc 11 and the rotor, and the top foil 14, the wave foil 13 and the rotor are normally and safely operated; when the rotor and the thrust disc 11 suddenly lose stability due to power failure or external impact and the like and move axially, the top foil 14 is in an extreme compression state, and when the top foil 14 is worn after long-term operation, the axial distance between the thrust disc 11 and the top foil 14 and the protective ring 15 is shortened, the axial gap between the protective ring 15 and the thrust disc 11 is less than or equal to the axial gap between the top foil 14 and the thrust disc 11, the axial distance between the thrust disc 11 and the protective ring 15 is equal to or shorter than the axial distance between the thrust disc 11 and the top foil 14, and the axial distance between the thrust disc 11 and the protective ring 15 is also shorter than the axial distance between the thrust disc 11 and the wave foil 13; when the thrust disc 11 moves axially, the thrust disc 11 will first contact the protective ring 15 with a shorter distance, so that the protective ring 15 can support and buffer between the thrust disc 11 and the top foil 14 and the wave foil 13, and can protect the top foil 14 and the wave foil 13 from being deformed beyond the design range, and can also protect the wave foil 13 outside the top foil 14 from being excessively deformed and losing elasticity due to the impact of the thrust disc 11 and the rotor.

[0063] As shown in FIGS. 1-4, the centrifugal compressor according to the second aspect of the present application comprises a casing, a stator, a rotor and the axial dynamic pressure bearing 1.

[0064] The casing has an axial bearing chamber; the stator and the rotor are arranged in the casing; the axial dynamic pressure bearing 1 is configured as the axial dynamic pressure bearing 1 of any one of the above embodiments, and is arranged in the axial bearing chamber of the casing, and the thrust disc 11 is connected to the rotor.

[0065] The stator and the rotor are arranged in the casing, and the stator and the rotor can jointly realize the function of the centrifugal compressor for compressing gas. The axial dynamic pressure bearing 1 can be arranged in the axial bearing chamber of the casing to be fixed at a predetermined position of the casing, and the thrust disc 11 of the axial dynamic pressure bearing 1 is connected to the rotor to axially suspend and support the rotor and improve the working performance of the rotor. Since the centrifugal compressor according to the second aspect of the present application comprises the axial dynamic pressure bearing 1 of any one of the above embodiments, the centrifugal compressor can protect the top foil 14, the wave foil 13 and the like when the rotor loses stability and is impacted, can improve the reliability and service life of the top foil 14 and the wave foil 13, can improve the working stability of the rotor, and can save maintenance costs; the centrifugal compressor can judge the running fault and the damage degree of the axial dynamic pressure bearing 1 through the contact conduction function to realize predictive maintenance, can avoid affecting the use of the axial dynamic pressure bearing 1 after the axial dynamic pressure bearing 1 is damaged, and can improve the working reliability and safety.

[0066] As shown in FIGS. 1-4, according to some embodiments of the present application, the centrifugal compressor further comprises: an impeller arranged on the thrust disc 11, the casing further comprises: a wheel cover, the impeller is arranged on one side of the wheel cover with a wheel cover seal, and on the other side with a wheel back seal, the axial gap between the protective ring 15 and the thrust disc 11 is smaller than the axial gap between the wheel cover seal and the impeller, and the axial gap between the protective ring 15 and the thrust disc 11 is also smaller than the axial gap between the wheel back seal and the thrust disc 11.

[0067] The impeller is arranged on the thrust disc 11 for gas flow guiding and compression; the wheel cover is used for supporting, connecting and sealing the impeller, and helps to maintain the balance of the rotor and reduce vibration caused by uneven mass distribution; wherein the impeller is arranged on one side of the wheel cover with a wheel cover seal, and on the other side with a wheel back seal, the wheel cover seal and the wheel back seal can improve the structural air tightness and enhance the anti-gas liquid leakage effect, and can improve the compression efficiency of the centrifugal compressor.

[0068] When the axial gap between the wheel cover seal and the impeller and the axial gap between the wheel back seal and the thrust disc 11 are smaller than or equal to the axial gap between the protective ring 15 and the thrust disc 11, it will cause poor anti-gas liquid leakage performance and reduce the overall structural operation stability, therefore, by limiting the size relationship of the axial gap between the wheel cover seal and the impeller, the axial gap between the wheel back seal and the thrust disc 11 and the axial gap between the protective ring 15 and the thrust disc 11 within the above range, the axial gap between the wheel cover seal and the impeller and the axial gap between the wheel back seal and the thrust disc 11 are relatively small, so as to adapt to the axial gap between the protective ring 15 and the thrust disc 11, which helps to optimize the sealing performance, improve the anti-gas leakage performance, improve the working efficiency, and improve the rotor operation stability.

[0069] As shown in FIGS. 1-4, according to some embodiments of the present application, the rotor comprises a primary rotor and a secondary rotor, the axial bearing chamber comprises a primary bearing chamber corresponding to the primary rotor and a secondary bearing chamber corresponding to the secondary rotor, the primary bearing chamber is arranged with a primary bearing, and the secondary bearing chamber is arranged with a secondary bearing, and at least one of the primary bearing and the secondary bearing is configured as an axial dynamic pressure bearing 1, the primary bearing and the secondary bearing are located on the axial two sides of the thrust disc 11.

[0070] The primary rotor and the secondary rotor can be coaxially arranged and connected, the primary bearing chamber corresponds to the primary rotor, the primary bearing is arranged in the primary bearing chamber and cooperates with the primary rotor, the secondary bearing chamber corresponds to the secondary rotor, the secondary bearing is arranged in the secondary bearing chamber and cooperates with the secondary rotor, and the primary bearing and the secondary bearing are respectively located on the two axial sides of the thrust disc 11. In this embodiment, the primary bearing and the secondary bearing can be arranged as follows: the primary bearing is configured as an axial dynamic pressure bearing 1, and the secondary bearing is configured as another bearing (such as a ball bearing); the primary bearing and the secondary bearing can also be arranged as follows: the secondary bearing is configured as an axial dynamic pressure bearing 1, and the primary bearing is configured as another bearing; the primary bearing and the secondary bearing can also be arranged as follows: the primary bearing and the secondary bearing are both configured as axial dynamic pressure bearings 1. By configuring at least one of the primary bearing and the secondary bearing as an axial dynamic pressure bearing 1, at least one axial dynamic pressure bearing 1 cooperates with the primary rotor and the secondary rotor, so that the working performance and the running stability of the rotor can be improved.

[0071] As shown in FIGS. 1-4, according to some embodiments of the present application, the primary bearing chamber and the secondary bearing chamber are located on the two axial sides, the thrust disc 11 includes: a first thrust disc corresponding to the primary rotor and a second thrust disc corresponding to the secondary rotor, the primary bearing cooperates with the first thrust disc, the secondary bearing cooperates with the second thrust disc, or the thrust disc 11 is arranged on the primary rotor or the secondary rotor, the primary bearing chamber and the secondary bearing chamber are located on the same axial side, and the primary bearing and the secondary bearing are located on the two axial sides of the thrust disc 11.

[0072] The thrust disc 11, the primary bearing chamber, the secondary bearing chamber and the like have various arrangement modes. In some embodiments, the primary rotor and the secondary rotor are both provided with the thrust disc 11 and correspond to the first thrust disc and the second thrust disc respectively, the primary bearing chamber and the secondary bearing chamber can be located on the two axial sides of the centrifugal compressor, so that the primary bearing and the secondary bearing are located on the two axial sides of the centrifugal compressor to respectively cooperate with the first thrust disc and the second thrust disc; in other embodiments, only one of the primary rotor and the secondary rotor is provided with the thrust disc 11, that is, the thrust disc 11 is arranged on the primary rotor or the secondary rotor, the primary bearing chamber and the secondary bearing chamber can be located on the same axial side of the centrifugal compressor, the primary bearing and the secondary bearing are located on the same axial side of the centrifugal compressor, and at the same time, the primary bearing and the secondary bearing are located on the two axial sides of the thrust disc 11 to cooperate with the thrust disc 11.

[0073] It can be understood that since at least one of the primary bearing and the secondary bearing is configured as an axial dynamic pressure bearing 1, no matter which arrangement mode of the above-mentioned arrangement modes is adopted by the thrust disc 11, the primary bearing chamber and the secondary bearing chamber, the working performance and the balance of the rotor can be optimized.

[0074] In addition, it should be noted that in the axial dynamic pressure bearing 1 according to another embodiment of the present application, the structure of the bearing seat 12, the wave foil 13, the top foil 14, the protective ring 15, the lead wire bundle 16, etc. are arranged on both sides of the thrust disc 11 in the axial direction. In each axial dynamic pressure bearing 1, the bearing seat 12 includes a first bearing seat 12a and a second bearing seat 12b located on both sides of the thrust disc 11, the wave foil 13 includes a first wave foil 13a and a second wave foil 13b located on both sides of the thrust disc 11, the top foil 14 includes a first top foil 14a and a second top foil 14b located on both sides of the thrust disc 11, the protective ring 15 includes a first protective ring 15a and a second protective ring 15b located on both sides of the thrust disc 11, the lead wire bundle 16 includes a first lead wire bundle 16a and a second lead wire bundle 16b located on both sides of the thrust disc 11, the insulating layer 17 includes a first insulating layer 17a and a second insulating layer 17b located on both sides of the thrust disc 11, and the potting layer 18 includes a first potting layer 18a and a second potting layer 18b located on both sides of the thrust disc 11.

[0075] As shown in FIGS. 1-4, according to some embodiments of the present application, the primary bearing and the secondary bearing are both configured as an axial dynamic pressure bearing 1, and the centrifugal compressor further comprises a detection module having a detection circuit, the detection circuit including: a first loop and a second loop, the first loop being a loop formed by connecting the lead wire bundle 16 of the primary bearing with the shell, the second loop being a loop formed by connecting the lead wire bundle 16 of the secondary bearing with the shell, and any loop being conductive, the detection module issuing an alarm.

[0076] The detection module has a detection circuit, the first loop in the detection circuit being a loop formed by connecting the lead wire bundle 16 of the primary bearing with the shell of the centrifugal compressor, when the thrust disc 11 presses against the protective ring 15 of the primary bearing, the first loop is conductive, the detection module can issue an alarm to remind that the primary bearing needs to be maintained and replaced or is abnormally running, etc. The second loop in the detection circuit is a loop formed by connecting the lead wire bundle 16 of the secondary bearing with the shell of the centrifugal compressor, when the thrust disc 11 presses against the protective ring 15 of the secondary bearing, the second loop is conductive, the detection module can issue an alarm to remind that the secondary bearing needs to be maintained and replaced or is abnormally running, etc. By setting the first loop and the second loop, the detection module can accurately remind which part of the primary bearing and the secondary bearing is abnormal, so as to accurately identify the fault and take preventive measures, which can improve the maintenance efficiency and convenience, reduce downtime and maintenance cost.

[0077] As shown in FIG. 5, according to the control method of the third embodiment of the present application, which is applicable to the centrifugal compressor of any one of the above embodiments, the control method includes: acquiring the conduction duration and the conduction frequency of the detection circuit; if the conduction duration exceeds a duration threshold or the conduction frequency exceeds a first frequency threshold, a fault is reported and the machine is stopped.

[0078] According to the control method of the third aspect of the present application, whether to report a fault and stop can be determined according to whether the on duration of the detection circuit exceeds the duration threshold or whether the on number of the detection circuit exceeds the first number threshold. When the on duration exceeds the duration threshold or the on number exceeds the first number threshold, a fault is reported and the machine is stopped, so that maintenance and replacement are performed in time, and the working performance, reliability and safety of the centrifugal compressor are improved.

[0079] It should be noted that the on duration described above can be a single on duration. When the single on duration exceeds the duration threshold, a fault can be reported and the machine can be stopped. The on duration described above can also be the sum of multiple on durations. When the sum of the multiple on durations exceeds the duration threshold, a fault can be reported and the machine can be stopped.

[0080] Correspondingly, the duration threshold can be single, for comparison with the single on duration. The duration threshold can also be cumulative, for comparison with the sum of the multiple on durations, to determine whether a fault needs to be reported and the machine needs to be stopped.

[0081] As shown in FIG. 5, according to some embodiments of the present application, the duration threshold is 30s-60s, and the first number threshold is 8-12.

[0082] If the duration threshold is too small or too large, or the first number threshold is too small or too large, the determination of whether to report a fault and stop will be inaccurate, which will affect the accurate alarm of the detection module. By setting the duration threshold and the first number threshold in the above range, the duration threshold and the first number threshold have reasonable range values. For example, the duration threshold can be 40s or 50s, and the first number threshold can be 9 or 10. In this way, by comparing the on duration and the on number of the detection circuit with the duration threshold and the first number threshold, the accuracy of the fault alarm of the detection module can be improved.

[0083] As shown in FIG. 5, according to some embodiments of the present application, the control method further comprises: obtaining the on number of the first loop and the second loop. The first loop is a loop formed by connecting the lead wire bundle of the primary bearing to the shell, and the second loop is a loop formed by connecting the lead wire bundle of the secondary bearing to the shell. Within the first time threshold, if the on number of the first loop exceeds the second number threshold, a primary bearing damage alarm is reported and the machine is stopped urgently. Within the first time threshold, if the on number of the second loop exceeds the second number threshold, a secondary bearing damage alarm is reported and the machine is stopped urgently.

[0084] When the detection circuit is turned on, it may be that the top foil 14 and the wave foil 13 of the axial dynamic pressure bearing 1 are deformed outward due to the impact of the axial dynamic pressure bearing 1 in a harsh working condition, the thrust disc 11 contacts the protection ring 15 of the axial dynamic pressure bearing 1, or the axial dynamic pressure bearing 1 is severely worn, and the detection circuit is turned on. Then the customer needs to be prompted to replace the axial dynamic pressure bearing 1 (the friction life of the axial dynamic pressure bearing 1 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 of the detection circuit is: within the first time threshold, the number of turn-ons of the first loop exceeds the second number threshold, then the first level bearing damage alarm is reported, and the machine is stopped urgently; within the first time threshold, the number of turn-ons of the second loop exceeds the second number threshold, then the second level bearing damage alarm is reported, and the machine is stopped urgently.

[0085] In addition, in some embodiments of the present application, the first time threshold is 30min-90min, the second number threshold is 8-12, and the second number threshold is greater than or equal to the first number threshold. Setting the first time threshold too small or too large, or the second number threshold too small or too large, will lead to inaccurate determination of the first level bearing and the second level bearing damage alarm, causing inconvenience to targeted maintenance and replacement. 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 30min or 60min, 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, the second number threshold is 11, and the first number threshold is at most 11. In this way, by comparing the on duration and the number of turn-ons of the detection circuit with the first time threshold and the second number threshold, the accuracy of the detection module in reporting the first level bearing and the second level bearing damage alarm can be improved, and the convenience and efficiency of maintenance and replacement can be improved.

[0086] It should be noted that the first number threshold is used as a criterion for determining whether the first level bearing, the second level bearing, and the rotor and other components are abnormal. When the first level bearing, the second level bearing, and the rotor and other components suddenly become abnormal, the first loop and the second loop will have short and few turn-ons. When the first loop and the second loop have long and multiple turn-ons, it means that the first level bearing, the second level bearing, and the rotor and other components are not suddenly abnormal, but the friction life of the first level bearing and the second level bearing has begun to approach the end. Therefore, the second number threshold is usually larger than the first number threshold.

[0087] In the description of the application, reference has been made to descriptive terms such as "one embodiment", "some embodiments", "an embodiment", "example", "specific example" or "some examples" etc. Such terminology means that a particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the application. The illustrative appearances of such terminology in various places in the specification does not necessarily refer to the same embodiment or example. Moreover, it is appreciated that the specific features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0088] Although embodiments of the present application have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations to these embodiments could be made without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. An axial hydrodynamic bearing, disposed on a rotor, characterized in that, include: Thrust plate and bearing housing; A corrugated foil and a top foil, wherein the corrugated foil is located between the top foil and the bearing housing and elastically pushes against the top foil, and the top foil is axially opposite to the thrust plate; A protective ring is disposed on the bearing seat; wherein, in the same axial direction, the axial clearance between the protective ring and the thrust plate, minus the axial clearance between the top foil and the thrust plate, is less than the thickness of the top foil.

2. The axial dynamic pressure bearing according to claim 1, characterized in that, Also includes: A lead wire harness is provided, one end of which is connected to the protective ring. The lead wire harness is wrapped with an insulating layer. The other end of the lead wire harness is led out and forms a detection circuit. The detection circuit is adapted to conduct when the thrust plate presses against the protective ring.

3. The axial dynamic pressure bearing according to claim 1 or 2, characterized in that, The protective ring is constructed of graphite.

4. The axial dynamic pressure bearing according to claim 3, characterized in that, The bearing housing is provided with a mounting groove, and at least a portion of the protective ring is disposed within the mounting groove.

5. The axial dynamic pressure bearing according to claim 4, characterized in that, The cross-sectional area of ​​the protective ring gradually decreases in the direction toward the thrust plate.

6. The axial dynamic pressure bearing according to claim 4, characterized in that, A potting layer is provided between the protective ring and the mounting groove to provide cushioning protection.

7. The axial hydrodynamic bearing according to any one of claims 1-6, characterized in that, After the top foil is under extreme compression or wear, the axial clearance between the protective ring and the thrust plate is less than or equal to the axial clearance between the top foil and the thrust plate.

8. A centrifugal compressor, characterized in that, include: A housing having an axial bearing chamber; A stator and a rotor, both of which are disposed within the housing; The axial dynamic pressure bearing according to any one of claims 1-7, wherein the axial dynamic pressure bearing is disposed in the axial bearing chamber, and the thrust plate is connected to the rotor.

9. The centrifugal compressor according to claim 8, characterized in that, The centrifugal compressor further includes an impeller disposed on the thrust plate, and the housing further includes a wheel cover. A wheel cover seal is disposed on one side of the impeller and the wheel cover, and a wheel back seal is disposed on the other side. The axial clearance between the protective ring and the thrust plate is smaller than the axial clearance between the wheel cover seal and the impeller. The axial clearance between the protective ring and the thrust plate is also smaller than the axial clearance between the wheel back seal and the thrust plate.

10. The centrifugal compressor according to claim 9, characterized in that, The rotor includes a primary rotor and a secondary rotor. The axial bearing chamber includes a primary bearing chamber corresponding to the primary rotor and a secondary bearing chamber corresponding to the secondary rotor. A primary bearing is provided in the primary bearing chamber, and a secondary bearing is provided in the secondary bearing chamber. At least one of the primary bearing and the secondary bearing is configured as an axial dynamic pressure bearing. The primary bearing and the secondary bearing are located on both sides of the thrust plate.

11. The centrifugal compressor according to claim 10, characterized in that, The primary bearing chamber and the secondary bearing chamber are located on opposite sides of the axial direction. The thrust plate includes a first thrust plate corresponding to the primary rotor and a second thrust plate corresponding to the secondary rotor. The primary bearing cooperates with the first thrust plate, and the secondary bearing cooperates with the second thrust plate. Alternatively, the thrust plate may be disposed on the primary rotor or the secondary rotor. The primary bearing chamber and the secondary bearing chamber are located on the same side of the axial direction, and the primary bearing and the secondary bearing are located on opposite sides of the axial direction of the thrust plate.

12. The centrifugal compressor according to claim 11, characterized in that, Both the primary bearing and the secondary bearing are configured as axial dynamic pressure bearings. The centrifugal compressor further includes a detection module with a detection circuit. The detection circuit includes a first circuit and a second circuit. The first circuit is formed by connecting the lead wire harness of the primary bearing to the housing. The second circuit is formed by connecting the lead wire harness of the secondary bearing to the housing. If either circuit is conducting, the detection module will issue an alarm.

13. A control method applicable to the centrifugal compressor according to any one of claims 8-12, characterized in that, include: Obtain the conduction duration and number of conductions of the detection circuit; If the conduction duration exceeds the duration threshold or the number of conductions exceeds the first count threshold, a fault will be reported and the system will be shut down.

14. The control method according to claim 13, characterized in that, The duration threshold is 30s to 60s, and the first number threshold is 8 to 12 times.

15. The control method according to claim 13, characterized in that, Also includes: Obtain the conduction counts of the first circuit and the second circuit. The first circuit is the circuit formed by connecting the lead wire harness of the first-stage bearing to the housing, and the second circuit is the circuit formed by connecting the lead wire harness of the second-stage bearing to the housing. If the number of times the first circuit is turned on exceeds the second threshold within the first time threshold, a first-level bearing damage alarm will be reported and the machine will be shut down immediately. If the number of times the second circuit is turned on exceeds the second threshold within the first time threshold, a secondary bearing damage alarm will be reported and the machine will be shut down urgently.

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