hydrostatic bearing assembly, compressor and refrigerant circulation system

Abstract

This invention discloses a hydrostatic bearing assembly, a compressor, and a refrigerant circulation system. The hydrostatic bearing assembly includes: a bearing body having an outer annular surface and an inner annular surface, and multiple throttling orifices on the bearing body; a fluid inlet for introducing external fluid on the outer annular surface, the fluid inlet communicating with the inlet of the throttling orifice, and the outlet of the throttling orifice located on the inner annular surface; a gas pipeline through which gas flows, communicating with the fluid inlet; a liquid pipeline through which liquid flows, communicating with the fluid inlet; and a valve assembly for controlling the opening and closing of the gas pipeline and the liquid pipeline. The hydrostatic bearing assembly, compressor, and refrigerant circulation system of this invention have a simple structure and low cost.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and more specifically, to a hydrostatic bearing assembly, a compressor, and a refrigerant circulation system. Background Technology

[0002] Traditional centrifugal compressors mostly use sliding bearings, requiring lubricating oil for bearing lubrication. This lubricating oil can enter the system, reducing centrifugal compressor efficiency. Furthermore, the lubricating oil needs regular replacement, incurring significant costs, and oil changes can disrupt the environment, creating oil sludge. Additionally, as the rotational speed increases, frictional losses and temperature rise of the lubricating oil increase rapidly, affecting unit performance and reliability. Therefore, the application of oil-free bearings is gaining increasing attention. Oil-free bearings include the following types:

[0003] Magnetic levitation bearings achieve rotor levitation through electromagnetic force, eliminating the need for lubrication. However, magnetic levitation requires electromagnetic bearings, high-precision sensors, and bearing controllers, resulting in complex control, large size, and high cost. Furthermore, due to their low damping, magnetic levitation bearings exhibit poor reliability under strong disturbance conditions.

[0004] Dynamic pressure air bearings utilize the pressure film formed by the rotation of the air film to suspend the rotor, achieving oil-free and frictionless operation. However, dynamic pressure air bearings have low load-bearing capacity, friction during start-up and shutdown, and short lifespan.

[0005] Hydrostatic air suspension bearings utilize external high-pressure gas passing through a throttling device to form a high-pressure gas film on the working surface, supporting rotor suspension and enabling oil-free and frictionless operation. These bearings are small in size, have a high load-bearing capacity, eliminate starting and stopping friction, and have a long service life, making them promising candidates for use in centrifugal compressors.

[0006] Centrifugal compressors use hydrostatic bearings (hydrostatic air suspension bearings) to achieve oil-free and frictionless operation. These bearings require high-pressure gas to operate, but the centrifugal compressor unit does not have high-pressure gas before startup. Therefore, a separate gas supply system is needed to ensure the hydrostatic bearings are supplied with gas. Due to the low density of gas, the gas supply system is also very large, resulting in high costs. Furthermore, if components in the gas supply system fail, the system depressurizes rapidly, easily leading to abnormal gas supply to the bearings and subsequent damage, resulting in even higher repair costs.

[0007] In summary, the air supply devices for hydrostatic bearings in the prior art are very large and have complex structures, resulting in high costs. Summary of the Invention

[0008] This invention provides a hydrostatic bearing assembly, a compressor, and a refrigerant circulation system to solve the problem that the gas supply device for hydrostatic bearings in the prior art is very large, has a complex structure, and results in high cost.

[0009] To achieve the above objectives, the present invention provides a hydrostatic bearing assembly, comprising: a bearing body having an outer annular surface and an inner annular surface, and a plurality of throttling orifices provided on the bearing body; a fluid inlet for introducing external fluid provided on the outer annular surface, the fluid inlet communicating with the inlet of the throttling orifice, and the outlet of the throttling orifice being provided on the inner annular surface; a gas pipeline through which gas flows, and the gas pipeline communicating with the fluid inlet; a liquid pipeline through which liquid flows, and the liquid pipeline communicating with the fluid inlet; and a valve assembly for controlling the opening and closing of the gas pipeline and the liquid pipeline.

[0010] Furthermore, the valve assembly includes: a first valve disposed on a gas pipeline to control the opening and closing of the gas pipeline; and a second valve disposed on a liquid pipeline to control the opening and closing of the liquid pipeline.

[0011] Furthermore, the valve assembly includes a three-way valve, the first port of which is connected to a gas line, the second port of which is connected to a liquid line, and the third port of which is connected to a fluid inlet; the three-way valve has a first state in which the first port and the third port are connected, and the three-way valve has a second state in which the second port and the third port are connected.

[0012] Furthermore, it also includes: a liquid pump, which is installed on the liquid pipeline and is used to pressurize the liquid and pump it to the fluid inlet.

[0013] Furthermore, the viscosity of the gas in the gas pipeline is less than 0.01 Pa·s; the viscosity of the liquid in the liquid pipeline is less than 0.01 Pa·s.

[0014] Furthermore, the ratio of the orifice depth to the orifice diameter is less than or equal to 20.

[0015] According to another aspect of the invention, a compressor is provided, comprising the above-described hydrostatic bearing assembly.

[0016] Furthermore, the compressor is a centrifugal compressor.

[0017] Furthermore, the compressor includes a shaft that mates with a hydrostatic bearing assembly, and there is a working clearance between the shaft and the inner ring surface, the working clearance being less than 0.02 mm.

[0018] Furthermore, the compressor is provided with a fluid channel, the first end of which is connected to the fluid inlet; the gas pipeline and the liquid pipeline are connected in parallel and then connected to the second end of the fluid channel.

[0019] According to another aspect of the present invention, a refrigerant circulation system is provided, including a compressor, wherein the compressor is the compressor described above.

[0020] Furthermore, it also includes a condenser; the first end of the gas pipeline is connected to the condenser, and the second end of the gas pipeline is connected to the fluid inlet; the first end of the liquid pipeline is connected to the condenser, and the second end of the liquid pipeline is connected to the fluid inlet; the gas in the condenser enters the gas pipeline, and the liquid in the condenser enters the liquid pipeline.

[0021] The hydrostatic bearing assembly of this invention can be supplied with either a general-purpose gas or a liquid to achieve bearing support. Upon initial startup, the gas line is closed while the liquid line is opened. Fluid is initially supplied to the bearing body via a liquid supply device through the liquid line. This liquid supply device is very small and has a relatively simple structure, minimizing costs. After a period of operation, the gas line is opened while the liquid line is closed. Fluid is then supplied to the bearing body via a gas supply device through the gas line. Due to the low density of gas, the gas supply device can continuously pressurize for an extended period without needing to reach a predetermined pressure in a short time. Therefore, a bulky gas supply device is not required, further simplifying the structure and minimizing costs. The hydrostatic bearing assembly of this invention can switch between liquid and gas operation, has a simple structure, is easy to maintain, and has low maintenance costs. Therefore, compared to existing hydrostatic bearings, the hydrostatic bearing assembly of this invention is smaller, simpler in structure, and lower in cost. Attached Figure Description

[0022] Figure 1 This is a three-dimensional schematic diagram of the bearing body of the hydrostatic bearing assembly according to an embodiment of the present invention;

[0023] Figure 2 This is a cross-sectional schematic diagram of the bearing body of the hydrostatic bearing assembly according to an embodiment of the present invention;

[0024] Figure 3 This is a partial structural schematic diagram of the bearing body of the hydrostatic bearing assembly according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the refrigerant circulation system according to an embodiment of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0027] See Figures 1 to 4As shown, according to an embodiment of the present invention, a hydrostatic bearing assembly is provided. The hydrostatic bearing assembly includes a bearing body 10, which has an outer annular surface 11 and an inner annular surface 12. A plurality of throttling orifices 20 are provided on the bearing body 10. A fluid inlet 31 for introducing external fluid is provided on the outer annular surface 11, and the fluid inlet 31 communicates with the inlet of the throttling orifice 20. The outlet of the throttling orifice 20 is located on the inner annular surface 12. The hydrostatic bearing assembly also includes a gas pipeline 51, a liquid pipeline 52, and a valve assembly. Gas flows through the gas pipeline 51, and the gas pipeline 51 communicates with the fluid inlet 31. Liquid flows through the liquid pipeline 52, and the liquid pipeline 52 communicates with the fluid inlet 31. The valve assembly is used to control the opening and closing of the gas pipeline 51 and the liquid pipeline 52.

[0028] The outer annular surface is typically fixed to the bearing housing or machine casing, serving to support the bearing body. The inner annular surface is usually fitted onto the shaft (usually the journal), forming a working clearance between the inner annular surface and the shaft to support the bearing. Hydrostatic bearing assemblies have a throttling orifice and a fluid inlet on the bearing body. External high-pressure fluid flows in through the fluid inlet on the bearing body and flows out through the throttling orifice, forming a high-pressure fluid film on the surface of the throttling orifice outlet, i.e., on the surface of the inner annular surface, thus providing support and achieving the bearing's function.

[0029] The hydrostatic bearing assembly of this invention can be supplied with either a general-purpose gas or a liquid to achieve bearing support. Upon initial startup, the gas line is closed while the liquid line is opened. Fluid is initially supplied to the bearing body via a liquid supply device through the liquid line. This liquid supply device is very small and has a relatively simple structure, minimizing costs. After a period of operation, the gas line is opened while the liquid line is closed. Fluid is then supplied to the bearing body via a gas supply device through the gas line. Due to the low density of gas, the gas supply device can continuously pressurize for an extended period without needing to reach a predetermined pressure in a short time. Therefore, a bulky gas supply device is not required, further simplifying the structure and minimizing costs. The hydrostatic bearing assembly of this invention can switch between liquid and gas operation, has a simple structure, is easy to maintain, and has low maintenance costs. Therefore, compared to existing hydrostatic bearings, the hydrostatic bearing assembly of this invention is smaller, simpler in structure, and lower in cost.

[0030] Gas and liquid pipelines can each correspond to a gas supply device and a liquid supply device, respectively. Through the cooperation of gas pipelines, liquid pipelines, and hydrostatic bearings, the hydrostatic bearing can operate as a standalone liquid hydrostatic bearing or a standalone gas hydrostatic bearing, and can also switch between liquid and gas operation. The appropriate method can be selected based on the specific situation. Because the two fluid media can be alternated, the requirements for the gas and liquid supply devices are lower, resulting in a smaller size and reduced cost.

[0031] In this embodiment, the valve assembly includes a first valve 61 and a second valve 62. The first valve 61 is disposed on the gas pipeline 51 to control the opening and closing of the gas pipeline 51; the second valve 62 is disposed on the liquid pipeline 52 to control the opening and closing of the liquid pipeline 52. In an embodiment not shown in the figures, the valve assembly includes a three-way valve. The first port of the three-way valve is connected to the gas pipeline 51, the second port of the three-way valve is connected to the liquid pipeline 52, and the third port of the three-way valve is connected to the fluid inlet 31. The three-way valve has a first state connecting the first port and the third port, and a second state connecting the second port and the third port. The three-way valve can control the opening and closing of the gas pipeline and the liquid pipeline.

[0032] Preferably, the hydrostatic bearing assembly further includes a liquid pump 70, which is installed on the liquid pipeline 52. The liquid pump 70 is used to pressurize the liquid and pump it to the fluid inlet 31. The liquid pump 70 can compensate for insufficient liquid pressure in the liquid supply device and ensure the fluid pressure of the hydrostatic bearing.

[0033] To further optimize the stability and reliability of the hydrostatic bearing assembly, in this embodiment, the viscosity of the gas in gas pipeline 51 is less than 0.01 Pa·s; and the viscosity of the liquid in liquid pipeline 52 is less than 0.01 Pa·s. When the fluid viscosity is too high, it can easily cause blockage, leading to the bearing's inability to function properly. Therefore, a low-viscosity fluid is used to ensure the stable operation of the hydrostatic bearing.

[0034] See Figure 3 The ratio of the hole depth h to the hole diameter d of the throttling orifice 20 is less than or equal to 20. If this ratio is greater than 20, the cost of machining the throttling orifice increases and the quality decreases. Therefore, the above improvement can reduce machining costs and make the bearing quality more stable.

[0035] Preferably, the orifice diameter d of the throttling orifice 20 is between 0.05 mm and 0.2 mm. The high-pressure fluid film support capacity is closely related to the size of the throttling orifice, with the orifice diameter d being between 0.05 mm and 0.2 mm. When the orifice diameter is less than 0.05 mm, the fluid carrying capacity after passing through the orifice is greatly reduced, and the machining difficulty of the orifice increases. When the orifice diameter is greater than 0.2 mm, the stability of the fluid film deteriorates, reducing bearing reliability.

[0036] There are multiple fluid inlets 31, each corresponding to a throttling orifice 20. The bearing housing 10 has multiple flow holes 32, each corresponding to a throttling orifice 20. The inlet of each throttling orifice 20 communicates with the fluid inlet 31 through the aforementioned flow holes 32. The throttling orifices 20 are arranged evenly along the annular surface of the bearing housing, and the arrangement can be selected based on the load-bearing capacity.

[0037] In this embodiment, the throttling orifice 20, the fluid inlet 31, and the flow passage 32 are coaxial. This structure makes the bearing housing easier to manufacture and reduces production costs.

[0038] According to an embodiment of the present invention, a compressor is provided, the compressor including the hydrostatic bearing assembly of the above embodiment.

[0039] The compressor in this embodiment is a centrifugal compressor. The refrigeration centrifugal compressor uses hydrostatic bearings, enabling oil-free and frictionless operation of the unit. The compressor's gas supply system or liquid supply system is smaller, less expensive, and operates more stably.

[0040] Combination Figure 3 As shown, the compressor includes a shaft that mates with a hydrostatic bearing assembly. There is a working clearance S between the shaft and the inner annular surface 12 of the hydrostatic bearing assembly, which is less than 0.02 mm. The working clearance S is less than 0.02 mm to ensure bearing rigidity; excessive clearance would cause a rapid decrease in bearing rigidity, thereby affecting the bearing's support performance.

[0041] The compressor is provided with a fluid passage 41, the first end of which is connected to the fluid inlet 31 of the hydrostatic bearing; the gas line 51 and the liquid line 52 are connected in parallel and then connected to the second end of the fluid passage 41. The fluid passage 41 is a structure designed to cooperate with the hydrostatic bearing assembly.

[0042] See Figure 4 According to an embodiment of the present invention, a refrigerant circulation system is provided, including a compressor 40, which includes the compressor described in the above embodiment, and the bearing body 10 of the hydrostatic bearing is mounted on a support structure inside the compressor.

[0043] Gas and liquid pipelines can each correspond to a gas supply device and a liquid supply device, respectively. Through the cooperation of gas pipelines, liquid pipelines, and hydrostatic bearings, the hydrostatic bearing can operate as a standalone liquid hydrostatic bearing or a standalone gas hydrostatic bearing, and can also switch between liquid and gas operation. The appropriate device can be selected based on the specific situation. Because the two fluid media can be alternated, the requirements for the gas and liquid supply devices are lower, the liquid supply device is smaller, and the structure of the gas and liquid supply devices is simple, resulting in low maintenance costs and overall cost reduction.

[0044] Preferably, the refrigerant circulation system further includes a liquid pump 70, which is installed on the liquid pipeline 52. The liquid pump 70 is used to pressurize the liquid and pump it to the fluid inlet 31. The liquid pump 70 can compensate for the problem of insufficient liquid pressure in the liquid supply device and ensure the fluid pressure of the hydrostatic bearing.

[0045] In the refrigerant circulation system, the compressor 40 is provided with a fluid passage 41, the first end of which is connected to the fluid inlet 31 of the hydrostatic bearing; the gas line 51 and the liquid line 52 are connected in parallel and then connected to the second end of the fluid passage 41. The fluid passage 41 is a structure designed to cooperate with the hydrostatic bearing assembly.

[0046] To further optimize the stability and reliability of the hydrostatic bearing assembly, in this embodiment, the viscosity of the gas in gas pipeline 51 is less than 0.01 Pa·s; and the viscosity of the liquid in liquid pipeline 52 is less than 0.01 Pa·s. When the fluid viscosity is too high, it can easily cause blockage, leading to the bearing's inability to function properly. Therefore, a low-viscosity fluid is used to ensure the stable operation of the hydrostatic bearing.

[0047] This embodiment aims to minimize the volume of the gas supply device or liquid supply device and maximize the utilization of various structures in the refrigerant circulation system. In this embodiment, the refrigerant circulation system also includes a condenser 80; a first end of a gas pipe 51 is connected to the condenser 80, and a second end of the gas pipe 51 is connected to the fluid inlet 31 of the hydrostatic bearing; a first end of a liquid pipe 52 is connected to the condenser 80, and a second end of the liquid pipe 52 is connected to the fluid inlet 31 of the hydrostatic bearing; gas from the condenser 80 enters the gas pipe 51, and liquid from the condenser 80 enters the liquid pipe 52. The connection position of the first end of the gas pipe 51 (upper part of the condenser) allows the gas pipe to receive the condenser gas portion 80a, and the connection position of the first end of the liquid pipe 52 (bottom of the condenser) allows the liquid pipe to receive the condenser liquid portion 80b.

[0048] Before startup, the refrigerant circulation system has the same pressure at all points, preventing free gas flow. The liquid line 52 is opened via the second valve 62, while the gas line 51 is closed. The liquid pump pressurizes the liquid at the bottom of the condenser and supplies it to the hydrostatic bearing inside the compressor to support the rotor. After the compressor starts running, the system pressure increases, and the condenser pressure is higher than that inside the compressor and the evaporator. When the pressure difference between the condenser and the compressor reaches the operating condition of the hydrostatic bearing, the gas line 51 is opened via the first valve 61, and the liquid line 52 is closed. The high-pressure liquid from the condenser enters the hydrostatic bearing inside the compressor, supporting the rotor.

[0049] The centrifugal compressor in the refrigerant circulation system uses hydrostatic bearings, enabling oil-free and frictionless operation of the unit. Before the refrigerant circulation system is started, the pressure is uniform throughout the system, and there is no high-pressure fluid required for the bearings. Therefore, a fluid pressurization device is needed. At this time, using a liquid as the working medium can reduce the size and cost of the pressurization device. However, when the refrigerant circulation system is operating normally, it contains both high-pressure liquid and high-pressure gas. In this case, the high-pressure fluid of the refrigerant circulation system can be used, and the fluid pressurization device can be turned off, improving system efficiency and extending the lifespan of the fluid pressurization device.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0052] Of course, the above are preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the basic principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A hydrostatic bearing assembly, characterized in that, include: The bearing body (10) has an outer ring surface (11) and an inner ring surface (12). The bearing body (10) is provided with a plurality of throttling holes (20). The outer ring surface (11) is provided with a fluid inlet (31) for introducing external fluid. The fluid inlet (31) is connected to the inlet of the throttling hole (20). The outlet of the throttling hole (20) is provided on the inner ring surface (12). Gas pipeline (51) through which gas flows, and gas pipeline (51) is connected to fluid inlet (31); A liquid pipeline (52) through which liquid flows, and the liquid pipeline (52) is connected to the fluid inlet (31); A valve assembly for controlling the opening and closing of the gas line (51) and the liquid line (52).

2. The hydrostatic bearing assembly according to claim 1, characterized in that, The valve assembly includes: A first valve (61) is provided on the gas pipeline (51) to control the opening and closing of the gas pipeline (51); A second valve (62) is provided on the liquid pipeline (52) to control the opening and closing of the liquid pipeline (52).

3. The hydrostatic bearing assembly according to claim 1, characterized in that, The valve assembly includes a three-way valve, the first port of which is connected to the gas line (51), the second port of which is connected to the liquid line (52), and the third port of which is connected to the fluid inlet (31). The three-way valve has a first state in which the first port and the third port are connected, and the three-way valve has a second state in which the second port and the third port are connected.

4. The hydrostatic bearing assembly according to claim 1, characterized in that, Also includes: A liquid pump (70) is installed on the liquid pipeline (52) and is used to pressurize the liquid and pump it to the fluid inlet (31).

5. The hydrostatic bearing assembly according to claim 1, characterized in that, The viscosity of the gas in the gas pipeline (51) is less than 0.01 Pa·s; The viscosity of the liquid in the liquid pipeline (52) is less than 0.01 Pa·s.

6. The hydrostatic bearing assembly according to claim 1, characterized in that, The ratio of the orifice depth (h) to the orifice diameter (d) of the throttling orifice (20) is less than or equal to 20.

7. A compressor, characterized in that, Includes the hydrostatic bearing assembly according to any one of claims 1 to 6.

8. The compressor according to claim 7, characterized in that, The compressor is a centrifugal compressor.

9. The compressor according to claim 7, characterized in that, The compressor includes a shaft that mates with the hydrostatic bearing assembly, and the shaft has a working clearance (S) between itself and the inner annular surface (12), the working clearance (S) being less than 0.02 mm.

10. The compressor according to claim 7, characterized in that, The compressor is provided with a fluid channel (41), and the first end of the fluid channel (41) is connected to the fluid inlet (31); The gas pipeline (51) and the liquid pipeline (52) are connected in parallel and then connected to the second end of the fluid channel (41).

11. A refrigerant circulation system, comprising a compressor (40), characterized in that, The compressor (40) is the compressor according to any one of claims 7 to 10.

12. The refrigerant circulation system according to claim 11, characterized in that, It also includes a condenser (80); The first end of the gas pipeline (51) is connected to the condenser (80), and the second end of the gas pipeline (51) is connected to the fluid inlet (31); The first end of the liquid pipeline (52) is connected to the condenser (80), and the second end of the liquid pipeline (52) is connected to the fluid inlet (31); The gas from the condenser (80) enters the gas line (51), and the liquid from the condenser (80) enters the liquid line (52).

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