A gas-float suspended centrifugal compressor

Abstract

The utility model provides a kind of air floatation suspension type centrifugal compressor, including shell, main shaft subassembly, air floatation bearing subassembly and motor subassembly.Shell includes the tubular main body being set along axial direction, front end is connected with front end cover, rear end is connected with rear end cover.Main shaft subassembly is worn in shell, front and rear ends are equipped with radial bearing respectively, front end is also equipped with thrust disc.Air floatation bearing subassembly includes front and rear radial air floatation bearing and thrust air floatation bearing, front and rear radial air floatation bearing is installed in front end cover and rear end cover respectively, thrust air floatation bearing is installed in front end cover, and radial clearance and axial clearance are formed with main shaft subassembly correspondingly.When main shaft rotates, clearance forms gas film, realizes the non-contact suspension support of main shaft subassembly.Motor subassembly includes stator and permanent magnet rotor, stator is fixed in tubular main body, rotor is coaxially fixed in main shaft subassembly and located in stator inside.This compressor compact structure reduces mechanical friction and energy consumption, improves stability and reliability under high speed operation.

Description

Technical Field

[0001] This utility model relates to the field of fluid machinery technology, and in particular to an air-float suspended centrifugal compressor. Background Technology

[0002] In modern compressor technology, centrifugal compressors are widely used in many fields such as air conditioning and refrigeration, aerodynamics, gas turbines, and petrochemical plants due to their advantages such as high efficiency, large flow rate, and compact structure. Traditional centrifugal compressors mostly use mechanical rolling bearings as the rotor support structure. During operation, frictional contact occurs, which easily generates energy loss, vibration, and noise. At the same time, they are highly dependent on the lubrication system, resulting in high maintenance costs and relatively low reliability.

[0003] To address the problems of traditional mechanical bearings, air bearing technology is increasingly being applied to high-speed rotating machinery, particularly suitable for applications requiring oil-free operation, cleanliness, high speed, and long service life. Air bearings utilize the air film formed in the bearing clearance during high-speed rotation to achieve non-contact support between the rotor and the bearing, thereby significantly reducing friction and improving system efficiency and service life. However, existing air bearings still present the following technical challenges when applied to centrifugal compressors: First, the clearance matching structure between the spindle assembly and the air bearing in the existing design is not reasonable enough, which makes it impossible to maintain the air film thickness stably across the entire operating range. This can easily cause contact wear of the rotor during start-up, shutdown, or load changes, affecting the bearing life and spindle stability.

[0004] Secondly, air bearings are usually directly connected to the housing, and insufficient rigidity or poor assembly positioning accuracy can lead to eccentric loads and reduce load-bearing capacity. At the same time, it is difficult to control the clearance between the thrust air bearing and the thrust plate, which makes the compressor susceptible to instability or axial drift under axial force fluctuation conditions.

[0005] Furthermore, traditional structures have shortcomings in the integrated design of the motor and bearing systems. For example, the heat generated by the stator windings is difficult to dissipate in time, which can easily cause the main shaft to overheat and deform, thus affecting the air film thickness and air flotation stability. In addition, for centrifugal compressors with multi-stage impeller structures, the lack of a reasonable axial and radial support layout increases the risk of system vibration and imbalance.

[0006] In summary, the air-bearing structure currently used in centrifugal compressors still has room for improvement in terms of bearing clearance arrangement, component rigidity design, heat dissipation structure and motor integration layout. There is an urgent need for a compact, stable, well-supported, and efficient air-film centrifugal compressor structure with high heat dissipation efficiency to improve overall operating performance and reliability. Utility Model Content

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide an air-float suspended centrifugal compressor. This compressor has a compact structure, stable support, and excellent air film performance.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A centrifugal compressor with air flotation includes a housing, a main shaft assembly, an air flotation bearing assembly, and a motor assembly. The housing includes a cylindrical body arranged axially, with a front end cover connected to the front end and a rear end cover connected to the rear end. The main shaft assembly is disposed within the housing, with a front radial bearing and a thrust disc on the outer circumference of its front end and a rear radial bearing on the outer circumference of its rear end. The air flotation bearing assembly includes a front radial air flotation bearing, a rear radial air flotation bearing, and a thrust air flotation bearing. A front radial air flotation bearing is installed inside the front end cover, and a first radial clearance is formed between the inner hole of the front radial air flotation bearing and the front radial bearing. A thrust air bearing is installed on the cover or the component connected to the front cover, and an axial clearance is formed between the thrust air bearing and the thrust disk; a rear radial air bearing is installed on the inner side of the rear cover, and a second radial clearance is formed between the inner hole of the rear radial air bearing and the rear radial bearing; the motor assembly includes a stator and a permanent magnet rotor, the stator is fixed inside the cylindrical body, and the permanent magnet rotor is coaxially fixed on the main shaft assembly and located inside the stator; when the main shaft assembly rotates, a radial air film is formed at the first radial clearance and the second radial clearance, and an axial air film is formed at the axial clearance, so as to jointly support the main shaft assembly to achieve non-contact levitation.

[0009] Furthermore, the inner hole of the front cover is fitted with a primary radial air bearing seat, and the inner hole of the primary radial air bearing seat is provided with a front radial air bearing; the rear cover is connected to a heat dissipation duct, the inner hole of the heat dissipation duct is fitted with a secondary radial air bearing seat, and the inner hole of the secondary radial air bearing seat is provided with a rear radial air bearing.

[0010] Furthermore, the first-stage radial air bearing housing and the inner hole of the front end cover, as well as the second-stage radial air bearing housing and the inner hole of the heat dissipation duct, are both radially and end-face fitted; the two ends of the front radial air bearing and the rear radial air bearing are axially limited by bearing pressure plates, and the bearing pressure plates are fixed on the corresponding first-stage radial air bearing housing or second-stage radial air bearing housing.

[0011] Furthermore, the front cover is connected to a primary flange, and the thrust air bearing is installed on the end face of the primary flange; the rear cover is connected to a cooling duct, and the cooling duct is connected to a secondary flange.

[0012] Furthermore, a primary three-dimensional impeller is coaxially fixed at the front end of the main shaft assembly, and a secondary three-dimensional impeller is coaxially fixed at the rear end of the main shaft assembly; the primary three-dimensional impeller is housed in a primary volute connected to a primary flange, and the secondary three-dimensional impeller is housed in a secondary volute connected to a secondary flange.

[0013] Furthermore, a heat dissipation impeller is coaxially fixed on the main shaft assembly. The heat dissipation impeller is located in the cavity between the cylindrical body and the heat dissipation duct. Louvered holes are opened on the side wall of the cylindrical body corresponding to the air inlet area of ​​the heat dissipation impeller.

[0014] Furthermore, the front end cap and the front straight opening of the cylindrical body, and the rear end cap and the rear straight opening of the cylindrical body, are both radially fitted with the end face and fastened with bolts.

[0015] The aforementioned air-float suspended centrifugal compressor achieves high-precision installation by setting radial air-float bearings and thrust air-float bearings at both ends of the main shaft assembly, and by using a front cover, rear cover, and bearing seat structure. This allows the main shaft assembly to form a stable air film at multiple gaps during operation, achieving non-contact, fully suspended support. Meanwhile, the motor assembly uses a permanent magnet rotor coaxially arranged with the stator, resulting in a compact structure. Combined with a cooling duct, cooling impeller, and louvers, it forms an effective cooling channel, thereby solving problems such as unstable air film support, high main shaft heat generation, and unreasonable structural layout in existing technologies, and improving the operational reliability and service life of the centrifugal compressor. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the compressor provided according to this utility model; Figure 2 This is a schematic diagram of air film formation on the spindle assembly according to the present invention. Detailed Implementation

[0017] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0018] In addition, to clearly illustrate the technical solution of this application, the following are also defined: Figure 1 The top, bottom, left, right, front, and back sides are shown.

[0019] like Figure 1 and Figure 2 As shown, this application provides an air-float suspended centrifugal compressor, including a housing 1, a main shaft assembly 2, an air-float bearing assembly 3, and a motor assembly 4.

[0020] Specifically, the housing 1 includes a cylindrical body 11 arranged axially, with a front cover 12 connected to the front end and a rear cover 13 connected to the rear end; the main shaft assembly 2 is inserted into the housing 1, with a front radial bearing 5a and a thrust disk 6 on the outer circumference of its front end and a rear radial bearing 5b on the outer circumference of its rear end; the air bearing assembly 3 includes a front radial air bearing 31a, a rear radial air bearing 31b, and a thrust air bearing 32; the front radial air bearing 31a is installed on the inner side of the front cover 12, and a first radial clearance is formed between the inner hole of the front radial air bearing 31a and the front radial bearing 5a; the front cover 12 or components connected to the front cover 12... A thrust air bearing 32 is installed on the upper part, and an axial gap is formed between the thrust air bearing 32 and the thrust disk 6; a rear radial air bearing 31b is installed on the inner side of the rear end cover 13, and a second radial gap is formed between the inner hole of the rear radial air bearing 31b and the rear radial bearing 5b; the motor assembly 4 includes a stator 41 and a permanent magnet rotor 42. The stator 41 is fixed inside the cylindrical body 11, and the permanent magnet rotor 42 is coaxially fixed on the main shaft assembly 2 and located inside the stator 41; when the main shaft assembly 2 rotates, a radial air film is formed at the first radial gap and the second radial gap, and an axial air film is formed at the axial gap, so as to jointly support the main shaft assembly 2 to achieve non-contact levitation.

[0021] The air-float centrifugal compressor provided in this embodiment achieves non-contact stable levitation of the rotor under all operating conditions by setting a reasonably matched first radial clearance, second radial clearance, and axial clearance between the main shaft assembly and the air-float bearing assembly. This effectively prevents contact wear during start-up, shutdown, and load changes, significantly improving bearing life and main shaft operating stability. Simultaneously, the air-float bearing, through precise matching with the front and rear end cover structures, enhances the overall rigidity and assembly precision of the system, reduces the risk of eccentric loads, strengthens the air film bearing capacity, and ensures stable operation even under axial force fluctuations, preventing main shaft drift or instability. The overall structure is compact, with a reasonable axial and radial support layout, making it particularly suitable for high-speed operation scenarios with multi-stage impellers. It possesses excellent vibration suppression capabilities and dynamic balance performance, significantly improving the operating efficiency, stability, and reliability of the compressor system, meeting the high-end application requirements of oil-free, clean, high-speed, and long-life applications.

[0022] The inner hole of the front cover 12 is fitted with a primary radial air bearing seat 33, and the inner hole of the primary radial air bearing seat 33 is fitted with a front radial air bearing 31a. The rear cover 13 is connected to a heat dissipation duct 50, and the inner hole of the heat dissipation duct 50 is fitted with a secondary radial air bearing seat 34, and the inner hole of the secondary radial air bearing seat 34 is fitted with a rear radial air bearing 31b. This embodiment improves the rigidity and assembly error problems caused by the direct connection of the air bearing to the end cover in the traditional design by setting an independent bearing seat structure, significantly improving the assembly accuracy and load-bearing capacity of the bearing, and avoiding eccentric loads and uneven air film caused by inaccurate positioning or structural deformation. The embedding method between the primary radial air bearing seat 33 and the front cover 12, and between the secondary radial air bearing seat 34 and the heat dissipation duct 50, gives the air bearing assembly good modularity and replaceability, facilitates maintenance and system upgrades, and improves the reliability and long-term stability of the system operation. The overall design is compact, which helps to shorten the length of the main shaft cantilever, reduce system vibration, and improve the smoothness and efficiency of the centrifugal compressor operation.

[0023] The primary radial air bearing seat 33 and the inner hole of the front cover 12, as well as the secondary radial air bearing seat 34 and the inner hole of the cooling duct 50, are both radially and end-face fitted. The two ends of the front radial air bearing 31a and the rear radial air bearing 31b are axially limited by bearing pressure plates 35, which are fixed to the corresponding primary radial air bearing seat 33 or secondary radial air bearing seat 34. This embodiment, through optimized design of the air bearing seat fit and axial limiting structure, effectively improves the installation rigidity and positioning accuracy of the bearing assembly, preventing structural loosening, displacement, or deformation under high speed, high load, or thermal expansion and contraction conditions. This ensures the stability of the air film thickness, reduces vibration and wear during operation, and improves the operational reliability and lifespan of the centrifugal compressor system. Simultaneously, the bearing pressure plate 35 has a simple structure, is easy to process and assemble, and can quickly complete the fixing and disassembly of the bearing, facilitating later maintenance and replacement, and improving the maintainability and ease of use of the product.

[0024] The front cover 12 is connected to a primary flange 14, and the thrust air bearing 32 is mounted on the end face of the primary flange 14. The rear cover 13 is connected to a cooling duct 50, and the cooling duct 50 is connected to a secondary flange 15. The introduction of the flange structure improves the positioning accuracy and installation stability of the thrust air bearing 32, avoiding problems such as uneven axial force and unstable air film caused by structural deformation or machining errors when directly mounted on the end cover or housing surface. The flange structure has good flatness and rigidity, which helps to form a uniform axial clearance and improve air film performance. At the same time, the split flange installation method facilitates the individual replacement and adjustment of the thrust bearing, improving maintenance efficiency.

[0025] A primary three-dimensional flow impeller 16 is coaxially fixed at the front end of the main shaft assembly 2, and a secondary three-dimensional flow impeller 17 is coaxially fixed at the rear end of the main shaft assembly 2. The primary three-dimensional flow impeller 16 is housed within a primary volute 18 connected to a primary flange 14, and the secondary three-dimensional flow impeller 17 is housed within a secondary volute 19 connected to a secondary flange 15. By setting multiple stages of three-dimensional flow impellers coaxially fixed at both ends of the main shaft, combined with the modular structure of the front and rear flanges and volutes, the multi-stage compression capacity and gas flow efficiency of the entire machine are improved. The three-dimensional flow impeller adopts a spatial flow design, which can adapt to complex airflow paths, effectively suppress airflow separation and turbulence, and improve compression efficiency and stability. The multi-stage volute structure realizes staged compression and flow control, which is beneficial to the adjustment and expansion of the overall performance of the compressor. The overall structure is compact, occupies little space, and is conducive to system integration. The symmetrical arrangement at the front and rear can also effectively balance axial force, reduce the burden on the thrust air bearing, and improve the system's operational stability and service life.

[0026] A cooling impeller 36 is coaxially fixed on the main shaft assembly 2. The cooling impeller 36 is located in the cavity between the cylindrical body 11 and the cooling duct 50. Louvered holes are opened on the side wall of the cylindrical body 11 corresponding to the air inlet area of ​​the cooling impeller 36. This embodiment enhances the heat dissipation efficiency of the compressor system by setting an active cooling impeller and louvered hole structure, effectively solving the problems of excessive temperature rise and poor heat dissipation in the traditional motor and bearing areas. The cooling impeller utilizes the rotational power of the main shaft without increasing additional energy consumption, achieving passive and efficient heat dissipation; the louvered hole structure prevents debris from entering and guides the airflow in a directional manner, improving the utilization efficiency of the cooling gas; the overall structure is compact and highly integrated, without affecting the operating space of the main shaft assembly and air bearing, effectively improving the operational stability and reliability of the whole machine under high load or high ambient temperature.

[0027] The front cover 12 and the front straight opening of the cylindrical body 11, and the rear cover 13 and the rear straight opening of the cylindrical body 11, are both radially and end-face mated and fastened with bolts. This radial and end-face composite mating structure provides higher positioning accuracy and assembly stability, effectively avoiding axial misalignment or eccentricity issues caused by machining or installation errors, thus improving the stability of film gas formation and the system's adaptability to high-speed rotation. The bolt fastening method facilitates disassembly and maintenance, enhancing the replaceability and maintainability of the compressor housing module. The overall structural design is simple and compact, reducing the number of connecting parts, contributing to the compressor's lightweight and integrated design, while also improving the system's vibration resistance and structural reliability during long-term operation.

[0028] The above description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A type of air-flotation suspended centrifugal compressor, characterized in that, It includes a housing (1), a spindle assembly (2), an air bearing assembly (3), and a motor assembly (4); The housing (1) includes a cylindrical body (11) arranged along the axial direction, with a front end cover (12) connected to the front end of the cylindrical body (11) and a rear end cover (13) connected to the rear end. The main shaft assembly (2) is installed inside the housing (1), with a front radial bearing (5a) and a thrust disk (6) on its front outer circumference; and a rear radial bearing (5b) on its rear outer circumference. The air bearing assembly (3) includes a front radial air bearing (31a), a rear radial air bearing (31b), and a thrust air bearing (32). The front radial air bearing (31a) is installed on the inner side of the front end cover (12), and a first radial clearance is formed between the inner hole of the front radial air bearing (31a) and the front radial bearing (5a); the thrust air bearing (32) is installed on the front end cover (12) or the component connected to the front end cover (12), and an axial clearance is formed between the thrust air bearing (32) and the thrust disk (6). The rear radial air bearing (31b) is installed on the inner side of the rear end cover (13), and a second radial clearance is formed between the inner hole of the rear radial air bearing (31b) and the rear radial bearing (5b). The motor assembly (4) includes a stator (41) and a permanent magnet rotor (42). The stator (41) is fixed inside the cylindrical body (11), and the permanent magnet rotor (42) is coaxially fixed on the main shaft assembly (2) and located inside the stator (41). When the spindle assembly (2) rotates, a radial air film is formed at the first radial gap and the second radial gap, and an axial air film is formed at the axial gap, so as to jointly support the spindle assembly (2) to achieve non-contact suspension.

2. The air-float suspension centrifugal compressor according to claim 1, characterized in that, The inner hole of the front cover (12) is fitted with a primary radial air bearing seat (33), and the inner hole of the primary radial air bearing seat (33) is provided with the front radial air bearing (31a); the rear cover (13) is connected to a heat dissipation duct (50), and the inner hole of the heat dissipation duct (50) is fitted with a secondary radial air bearing seat (34), and the inner hole of the secondary radial air bearing seat (34) is provided with the rear radial air bearing (31b).

3. The air-float suspension centrifugal compressor according to claim 2, characterized in that, The first-stage radial air bearing seat (33) and the inner hole of the front end cover (12) and the second-stage radial air bearing seat (34) and the inner hole of the heat dissipation duct (50) are both radially and end-face fit; the two ends of the front radial air bearing (31a) and the rear radial air bearing (31b) are respectively axially limited by bearing pressure plates (35), and the bearing pressure plates (35) are fixed on the corresponding first-stage radial air bearing seat (33) or second-stage radial air bearing seat (34).

4. The air-float suspension centrifugal compressor according to claim 1, characterized in that, The front end cover (12) is connected to a primary flange (14), and the thrust air bearing (32) is installed on the end face of the primary flange (14); the rear end cover (13) is connected to a heat dissipation duct (50), and the heat dissipation duct (50) is connected to a secondary flange (15).

5. The air-float suspension centrifugal compressor according to claim 4, characterized in that, The front end of the main shaft assembly (2) is coaxially fixed with a first-stage three-dimensional impeller (16), and the rear end of the main shaft assembly (2) is coaxially fixed with a second-stage three-dimensional impeller (17); the first-stage three-dimensional impeller (16) is housed in a first-stage volute (18) connected to the first-stage flange (14), and the second-stage three-dimensional impeller (17) is housed in a second-stage volute (19) connected to the second-stage flange (15).

6. The air-float suspension centrifugal compressor according to claim 4, characterized in that, A heat dissipation impeller (36) is also coaxially fixed on the main shaft assembly (2). The heat dissipation impeller (36) is located in the cavity between the cylindrical body (11) and the heat dissipation duct (50). The side wall of the cylindrical body (11) is provided with louvers corresponding to the air inlet area of ​​the heat dissipation impeller (36).

7. The air-float suspension centrifugal compressor according to claim 1, characterized in that, The front end cap (12) and the front straight opening of the cylindrical body (11), and the rear end cap (13) and the rear straight opening of the cylindrical body (11) are all radially fitted with the end face and fastened by bolts.

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