Two-stage oil-gas separator and oil-gas separation method

Abstract

The invention relates to a two-stage oil-gas separator which comprises an outer cylinder, a top cover and a ventilation pipe. The inner cylinder is coaxially arranged in the outer cylinder, and a cavity defined by the outer cylinder is divided into an outer cavity body and an inner cavity body. The first oil-gas separation cavity is an outer cavity, the second oil-gas separation cavity is an inner cavity, and the rotational flow chamber is arranged between the first oil-gas separation cavity and the second oil-gas separation cavity and coaxially installed at the top end of the second oil-gas separation cavity. Meanwhile, an oil-gas separation method is provided, in the first oil-gas separation cavity, lubricating oil is thrown to the inner wall face of the outer barrel, spirally ascends along the outer wall face of the inner barrel, tangentially enters the second oil-gas separation cavity through a plurality of connecting channels, is thrown to the inner wall face of the inner barrel and spirally descends along the inner wall of the inner barrel under the action of gravity and inertia, and then enters the second oil-gas separation cavity. After reaching the bottom of the second oil-gas separation cavity, the oil flows into a cavity of the base and then flows back to the lubricating oil tank through an oil supply port in the side face of the base; two-stage oil-gas separation is carried out on an oil-gas mixture, and the oil-gas separation efficiency is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of oil-gas separation technology for aero-engines. Background Technology

[0002] The lubricating oil system is one of the core systems in an aero-engine, mainly including the oil supply system, oil return system, and ventilation system. The oil supply system is mainly responsible for providing clean lubricating oil at appropriate pressure to the various lubrication components of the engine. The oil return system is mainly responsible for drawing back the high-temperature lubricating oil after the engine has been working, separating the air in the return oil, cooling it through the lubricating oil radiator (the system is a forward circulation system), and sending it back to the lubricating oil tank. The ventilation system is mainly responsible for expelling the sealed air that enters the lubricating oil chamber and maintaining the pressure of each lubricating oil chamber required for the normal operation of the lubricating oil system.

[0003] When the lubricating oil system is operating, the oil supply system draws lubricating oil from the oil tank into the bearing cavity and accessory housing to lubricate and cool the high-speed rotating bearings and gears. To prevent lubricating oil leakage into the aircraft engine, a sealing structure, typically a grate seal, needs to be designed inside the engine. Air is usually drawn from the compressor intermediate stage to seal the bearing cavity. This process introduces some lubricating oil droplets into the airflow path, resulting in oil loss due to the large volume of sealing air. Furthermore, some air mixes into the lubricating oil flow path, reducing oil quality, weakening lubrication, and decreasing heat exchange efficiency. Therefore, an oil-air separator is typically designed into the lubricating oil return path and the return oil system to separate air from the lubricating oil, improving oil quality and enhancing lubrication and cooling of the bearings and gears. The function of the oil-air separator is to separate gas from the return oil, ensuring the normal circulation of the lubricating oil system.

[0004] Currently, the most commonly used oil-gas separators in aero-engine lubrication systems are centrifugal oil-gas separators and hydrodynamic oil-gas separators. Hydrodynamic oil-gas separators have advantages such as simple structure, no rotating parts, and high separation efficiency, and are widely used in aero-engine lubrication systems. They are typically installed inside the oil tank, as seen in the oil tanks of engines like the V2500 and CFM56. Centrifugal oil-gas separators rely on a rotating shaft to drive a rotor, achieving gas separation from the lubrication oil through centrifugal force. This is the most efficient oil-gas separation device in engine lubrication systems; the WJ5, P11, and JT8D all use centrifugal oil-gas separators. In addition, other types of oil-gas separators exist, such as flat-plate and suction-pipe types. The WP7 and Spey engines are designed with appropriate separation devices to achieve degassing based on actual needs.

[0005] However, existing oil-gas separators can only separate some air from the lubricating oil, which is inefficient. This causes air to enter the oil tank, reducing the quality of the lubricating oil and still affecting the normal operation of the engine. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art by providing a two-stage oil-gas separator and oil-gas separation method that is simple in structure, has high separation efficiency, and can ensure effective separation of gas and lubricating oil.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a two-stage oil-gas separator, comprising an outer cylinder and a top cover of the oil-gas separator, and a ventilation pipe provided on the top cover for discharging the separated gas; The inner cylinder is coaxially set inside the outer cylinder, dividing the cavity enclosed by the outer cylinder into an outer cavity and an inner cavity. The upper section of the inner cylinder is a large-diameter cylindrical section, the lower section is a small-diameter cylindrical section, and the middle section is a conical section that is larger at the top and smaller at the bottom. The large-diameter end and the small-diameter end of the conical section are matched with the diameters of the large-diameter cylindrical section and the small-diameter cylindrical section, respectively, and are integrally set. The conical section is used to increase the swirl velocity. The first oil-gas separation chamber is the outer cavity, and the second oil-gas separation chamber is the inner cavity; The oil return port is connected to the first oil-gas separation chamber and is located on the outer cylinder. The high-temperature lubricating oil drawn back from various parts of the engine enters the first oil-gas separation chamber tangentially through the oil return port. A cyclone chamber is disposed between the first oil-gas separation chamber and the second oil-gas separation chamber, and is coaxially mounted at the top of the second oil-gas separation chamber; Multiple connecting channels are tangentially arranged on the side wall of the cyclone chamber to tangentially introduce the lubricating oil accumulated in the first oil-gas separation chamber into the second oil-gas separation chamber; The air vents are set on the side wall of the vortex chamber between the two connecting channels along the axial direction of the outer cylinder, and the top of the air vents is connected to the ventilation pipe. The base is located at the bottom of the second oil-gas separation chamber, and the second oil-gas separation chamber is connected to the inner cavity of the base. An oil supply port is provided on the base for delivering the lubricating oil obtained from the secondary separation.

[0008] Furthermore, the oil return port is located on the outer cylinder above the base, so that the lubricating oil entering the oil-gas separator can first accumulate at the bottom of the first oil-gas separation chamber, and gradually spiral up in the first oil-gas separation chamber, and enter the second oil-gas separation chamber at the top of the first separation chamber.

[0009] Furthermore, the distance between the oil return port and the base is 4~8mm, which is used to provide reserved space for the accumulation of oil-gas mixture.

[0010] Furthermore, the height ratio of the upper section, middle section and lower section of the inner cylinder is 1:1:3; The radius ratio of the large diameter end to the small diameter end of the conical section is 4:3. The upper section of the inner cylinder is 5-8 mm away from the inner wall of the first-stage oil-gas separation chamber, and the lower section is 12-16 mm away from the inner wall of the first-stage oil-gas separation chamber.

[0011] Furthermore, the axial height difference between the sidewall of the second oil-gas separation chamber and the inlet of the multiple connecting channels is 5~10 mm, which is used to use the pressure difference to send the oil-gas mixture that was not separated in the first stage into the second oil-gas separation chamber for further separation, while preventing backfilling.

[0012] Furthermore, the oil return port is a pipe with a square cross-section, which is used to improve sealing performance, connection strength, and adaptability of oil and gas flow.

[0013] Furthermore, the ventilation duct is coaxially arranged with the outer cylinder and the inner cylinder.

[0014] Furthermore, the swirling chamber is a vertical cylindrical-conical composite cavity that is closed at the top and tapered at the bottom. It generates high-speed swirling flow by relying on the tangential inlet formed by multiple connecting channels on the wall, thereby enabling the lubricating oil that has passed through the first oil-gas separation chamber to enter the second oil-gas separation chamber for further separation through the tangential inlet formed by the multiple connecting channels.

[0015] Furthermore, the height of the vortex chamber is 3~6mm; the axial angle between the connecting channel and the wall of the inner cylinder is 30°~60°.

[0016] The present invention also provides an oil-gas separation method for a two-stage oil-gas separator as described above, comprising the following steps: The high-temperature lubricating oil drawn back from various parts of the engine by the return oil pump forms an oil-gas mixture due to continuous suction. The oil-gas mixture enters the first oil-gas separation chamber tangentially through the return oil port and accumulates at the bottom of the first oil-gas separation chamber. Under the action of inertia, it gradually spirals upward inside the first oil-gas separation chamber. At this time, inside the first oil-gas separation chamber, the oil-gas mixture is affected by centrifugal force. The denser lubricating oil is thrown towards the inner wall of the outer cylinder and spirals upward along the outer wall of the inner cylinder. After the oil-gas mixture reaches the top of the first oil-gas separation chamber, it enters the second oil-gas separation chamber tangentially through multiple connecting channels 9. At the same time, the less dense gas, under the action of centrifugal force and centripetal force, gathers towards the center and spirals upward along the outer wall of the inner cylinder in the first oil-gas separation chamber. After reaching the top of the first oil-gas separation chamber, it enters the ventilation pipe through the air hole and is discharged through the ventilation pipe. However, one oil-gas separation cannot completely separate the lubricating oil and gas in the oil-gas mixture. Therefore, in the second oil-gas separation chamber, the oil-gas mixture after the first separation will be separated again. Inside the second oil-gas separation chamber, under the action of centrifugal force, the denser lubricating oil is thrown towards the inner wall of the inner cylinder. Under the action of gravity and inertia, it spirals down along the inner wall of the inner cylinder and flows into the cavity of the base after reaching the bottom of the second oil-gas separation chamber. Then, it flows back to the lubricating oil tank through the oil supply port on the side of the base. At the same time, the less dense gas, under the action of centrifugal force and centripetal force, gathers towards the center. Under the action of inertia, it moves along the axial direction of the inner cylinder towards the ventilation pipe. When it reaches the opening of the ventilation pipe, it enters the ventilation pipe and is discharged through the ventilation pipe.

[0017] The beneficial effects of this invention are: this invention designs a two-stage oil-gas separation chamber to separate the oil-gas mixture in two stages, thereby improving the oil-gas separation efficiency and having good engineering application value. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the appearance of the oil-gas separator of the present invention; Figure 2 This is a schematic diagram of the internal structure of the oil-gas separator of the present invention; Figure 3 This is a schematic diagram of the vortex chamber structure of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Ventilation pipe; 2. Outer cylinder; 21. Primary oil-gas separation chamber; 22. Secondary oil-gas separation chamber; 3. Base; 4. Oil return port; 5. Oil supply port; 6. Swirl chamber; 7. Inner cylinder; 8. Air hole; 9. Connecting channel; 10. Top cover. Detailed Implementation

[0020] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] To achieve the above objectives, the present invention provides the following specific embodiments: Example 1: As Figure 1-3 As shown, a two-stage oil-gas separator, such as Figure 1 As shown, it includes an outer cylinder 2 and a top cover 10 of an oil-gas separator, and a ventilation pipe 1 provided on the top cover 10 for discharging the separated gas. like Figure 2 As shown, the inner cylinder 7 is coaxially arranged inside the outer cylinder 2, dividing the cavity enclosed by the outer cylinder 2 into an outer cavity and an inner cavity; the upper section of the inner cylinder 7 is a large-diameter cylindrical section, the lower section is a small-diameter cylindrical section, and the middle section is a conical section that is larger at the top and smaller at the bottom. The large-diameter end and the small-diameter end of the conical section are matched with the diameters of the large-diameter cylindrical section and the small-diameter cylindrical section, respectively, and are integrally set. The conical section is used to increase the swirling speed. The height ratio of the upper, middle and lower sections of the inner cylinder 7 is 1:1:3; the radius ratio of the large diameter end to the small diameter end of the conical section, i.e. the middle section, is 4:3; the upper section of the inner cylinder 7 is 5~8mm away from the inner wall of the first oil-gas separation chamber 211, and the lower section is 12~16mm away from the inner wall of the first oil-gas separation chamber 211. The first oil-gas separation chamber 21 is the outer cavity, and the second oil-gas separation chamber 22 is the inner cavity; The oil return port 4 is connected to the first oil-gas separation chamber 21 and is set on the outer cylinder 2. The high-temperature lubricating oil drawn back from various parts of the engine enters the first oil-gas separation chamber 21 tangentially through the oil return port 4. like Figure 3 As shown, the cyclone chamber 6 is disposed between the first oil-gas separation chamber 21 and the second oil-gas separation chamber 22, and is coaxially mounted at the top of the second oil-gas separation chamber 22; The cyclone chamber 6 is a vertical cylindrical-conical composite cavity that is closed at the top and tapered at the bottom. It generates high-speed swirl by relying on the tangential inlet formed by multiple connecting channels 9 on the wall. This allows the lubricating oil that has passed through the first oil-gas separation chamber 21 to enter the second oil-gas separation chamber 22 for further separation through the tangential inlet formed by the multiple connecting channels 9.

[0022] The height of the vortex chamber 6 is 3~6mm; the axial angle between the connecting channel 9 and the wall of the inner cylinder 7 is 30°~60°.

[0023] Multiple connecting channels 9 are tangentially arranged on the side wall of the cyclone chamber 6 to tangentially introduce the lubricating oil accumulated in the first oil-gas separation chamber 21 into the second oil-gas separation chamber 22. The axial height difference between the side wall of the second oil-gas separation chamber 22 and the inlet of the multiple connecting channels 9 is 5~10 mm. This is used to send the oil-gas mixture that was not separated in the first stage into the second oil-gas separation chamber 22 for further separation by utilizing the pressure difference, while preventing backfilling. Air holes 8 are arranged along the axial direction of the outer cylinder 2 on the side wall of the vortex chamber 6 between the two connecting channels 9, and the top of the air holes 8 is connected to the ventilation pipe 1. The base 3 is located at the bottom of the second oil-gas separation chamber 22, which is connected to the inner cavity of the base 3. The base 3 is provided with an oil supply port 5 for sending out the lubricating oil obtained from the secondary separation.

[0024] The oil return port 4 is located on the outer cylinder 2 above the base 3. This allows the lubricating oil entering the oil-gas separator to first accumulate at the bottom of the first oil-gas separation chamber 21, then gradually spiral upwards within the first chamber, entering the second oil-gas separation chamber 22 at the top of the first chamber 21. The distance between the oil return port 4 and the base 3 is 4-8 mm, providing reserved space for the oil-gas mixture to accumulate. The oil return port 4 is a square-section pipe to improve sealing, connection strength, and adaptability to oil and gas flow rates.

[0025] Ventilation duct 1 is coaxially arranged with outer cylinder 2 and inner cylinder 7.

[0026] Example 2: Figure 1-3 As shown, the inner cylinder 7 is the same as in Embodiment 1, except that: the heights of the upper, middle, and lower sections of the inner cylinder 7 are 53mm, 51mm, and 150mm, respectively; the radius of the large diameter end of the conical section, i.e., the middle section, is 32mm, and the radius of the small diameter end is 24mm; the upper section of the inner cylinder 7 is 6mm away from the inner wall of the first oil-gas separation chamber 211, and the lower section is 14mm away from the inner wall of the first oil-gas separation chamber 211. The height of the vortex chamber 6 is 4mm; the axial angle between the connecting channel 9 and the wall of the inner cylinder 7 is 32.6°.

[0027] Figure 1 This is a schematic diagram of the oil-gas separator, which is placed inside the lubricating oil tank. At the bottom of the first oil-gas separation chamber 21, there is a rectangular oil return port 4 tangent to the wall of the primary oil-gas separation chamber. The oil-gas mixture enters the first oil-gas separation chamber 21 through the oil return port. The upper end of the first oil-gas separation chamber 21 is connected to a ventilation pipe 1. After the oil-gas mixture is separated, the gas is discharged from the ventilation pipe 1.

[0028] The lubricating oil then enters the secondary oil-gas separation chamber 7. The upper wall of the secondary oil-gas separation chamber 7 is connected to the ventilation pipe 1, and the lower wall extends into the base and is directly connected to the base. The lubricating oil obtained after the two-stage oil-gas separation can directly enter the cavity of the base. The base 3 is connected to the lower end of the primary oil-gas separation chamber 2, and there is an oil supply port 5 on the side of the base.

[0029] Figure 2 , Figure 3 These are schematic diagrams of the internal structure of the oil-gas separator. The top of the first oil-gas separation chamber 21 is a vortex chamber structure with air holes 8 and a cavity connection channel 9, which are respectively connected to the ventilation pipe 1 and the secondary oil-gas separation chamber. The gas separated by the first-stage oil-gas separation chamber enters the ventilation pipe 1 through the holes 8; the lubricating oil enters the secondary oil-gas separation chamber through the cavity connection channel for further oil-gas separation. After separation, the gas is discharged through the ventilation pipe 1, while the lubricating oil flows along the wall into the base 3 and exits the oil-gas separator through the oil supply port.

[0030] Example 3: As Figure 2 As shown, the present invention also provides an oil-gas separation method for a two-stage oil-gas separator as described in Examples 1 and 2, comprising the following steps: The high-temperature lubricating oil drawn back from various parts of the engine by the return oil pump forms an oil-gas mixture due to continuous suction. The oil-gas mixture enters the first oil-gas separation chamber 21 tangentially through the return oil port 4 and accumulates at the bottom of the first oil-gas separation chamber 21. Under the action of inertia, it gradually spirals upward inside the first oil-gas separation chamber 21. At this time, the oil-gas mixture inside the first oil-gas separation chamber 21 is affected by centrifugal force. The denser lubricating oil is thrown towards the inner wall of the outer cylinder 2 and spirals upward along the outer wall of the inner cylinder 7. After the oil-gas mixture reaches the top of the first oil-gas separation chamber 21, it enters the second oil-gas separation chamber 22 tangentially through multiple connecting channels 9. At the same time, the less dense gas, under the action of centrifugal force and centripetal force, gathers towards the center and spirals upward along the outer wall of the inner cylinder 7 in the first oil-gas separation chamber 21. After reaching the top of the first oil-gas separation chamber 21, it enters the ventilation pipe 1 through the air hole 8 and is discharged through the ventilation pipe 1. However, at this time, one oil-gas separation cannot completely separate the lubricating oil and gas in the oil-gas mixture. Therefore, in the second oil-gas separation chamber 22, the oil-gas mixture after the first separation will be separated again. Inside the second oil-gas separation chamber 22, under the action of centrifugal force, the denser lubricating oil is thrown towards the inner wall of the inner cylinder 7, and under the action of gravity and inertia, it spirals down along the inner wall of the inner cylinder 7. After reaching the bottom of the second oil-gas separation chamber 22, it flows into the cavity of the base 3, and then flows back to the lubricating oil tank through the oil supply port 5 on the side of the base 3. At the same time, the less dense gas, under the action of centrifugal force and centripetal force, gathers towards the center. Under the action of inertia, it moves along the axial direction of the inner cylinder 7 towards the ventilation pipe 1. When it reaches the opening of the ventilation pipe 1, it enters the ventilation pipe 1 and is discharged through the ventilation pipe 1.

[0031] Figure 2 As shown in the arrows and graphics, circles of different sizes represent oil-gas mixtures, three-dimensional arrows indicate the spiral direction of the oil-gas mixture, short, thick arrows indicate the flow path of the separated gas, and long, thin arrows indicate the flow path of the separated lubricating oil.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A two-stage oil-gas separator, characterized in that, It includes an outer cylinder (2) and a top cover (10) of an oil-gas separator, and a ventilation pipe (1) provided on the top cover (10) for discharging the separated gas. The inner cylinder (7) is coaxially set inside the outer cylinder (2), dividing the cavity enclosed by the outer cylinder (2) into an outer cavity and an inner cavity; the upper section of the inner cylinder (7) is a large-diameter columnar section, the lower section is a small-diameter columnar section, and the middle section is a conical section with a larger upper section and a smaller lower section. The large-diameter end and the small-diameter end of the conical section are matched with the diameters of the large-diameter columnar section and the small-diameter columnar section, respectively, and are set as a whole. The conical section is used to increase the swirling speed. The first oil-gas separation chamber (21) is the outer cavity, and the second oil-gas separation chamber (22) is the inner cavity; The oil return port (4) is connected to the first oil-gas separation chamber (21) and is set on the outer cylinder (2). The high-temperature lubricating oil drawn back from various parts of the engine enters the first oil-gas separation chamber (21) tangentially through the oil return port (4). The cyclone chamber (6) is located between the first oil-gas separation chamber (21) and the second oil-gas separation chamber (22), and is coaxially installed at the top of the second oil-gas separation chamber (22); Multiple connecting channels (9) are tangentially arranged on the side wall of the cyclone chamber (6) to tangentially introduce the lubricating oil accumulated in the first oil-gas separation chamber (21) into the second oil-gas separation chamber (22); The air hole (8) is set on the side wall of the vortex chamber (6) between the two connecting channels (9) along the axial direction of the outer cylinder (2). The top of the air hole (8) is connected to the ventilation pipe (1). The base (3) is located at the bottom of the second oil-gas separation chamber (22). The second oil-gas separation chamber (22) is connected to the inner cavity of the base (3). An oil supply port (5) is provided on the base (3) for sending out the lubricating oil obtained from the secondary separation.

2. The two-stage oil-gas separator as described in claim 1, characterized in that, The oil return port (4) is located on the outer cylinder (2) above the base (3) so that the lubricating oil entering the oil-gas separator can first accumulate at the bottom of the first oil-gas separation chamber (21) and gradually spiral up in the first oil-gas separation chamber (21) and enter the second oil-gas separation chamber (22) at the top of the first separation chamber (21).

3. The two-stage oil-gas separator as described in claim 2, characterized in that, The distance between the oil return port (4) and the base (3) is 4~8mm, which is used to provide reserved storage space for the oil-gas mixture.

4. The two-stage oil-gas separator as described in claim 1, characterized in that, The height ratio of the upper, middle and lower sections of the inner cylinder (7) is 1:1:3; The conical segment, that is, the radius ratio of the large diameter end to the small diameter end of the middle section, is 4:3; The upper section of the inner cylinder (7) is 5-8 mm away from the inner wall of the first-stage oil-gas separation chamber (21), and the lower section is 12-16 mm away from the inner wall of the first-stage oil-gas separation chamber (21).

5. The two-stage oil-gas separator as described in claim 1, characterized in that, The axial height difference between the sidewall of the second oil-gas separation chamber (22) and the inlet of the multiple connecting channels (9) is 5~10 mm. This is used to send the oil-gas mixture that was not separated in the first step into the second oil-gas separation chamber (22) for further separation by utilizing the pressure difference, while preventing backfilling.

6. The two-stage oil-gas separator as described in claim 1, characterized in that, The oil return port (4) is a square-section pipe used to improve sealing, connection strength and adaptability of oil and gas flow.

7. The two-stage oil-gas separator as described in claim 1, characterized in that, The ventilation pipe (1) is coaxially arranged with the outer cylinder (2) and the inner cylinder (7).

8. The two-stage oil-gas separator according to any one of claims 1-7, characterized in that, The swirling chamber (6) is a vertical cylindrical-conical composite cavity with a closed upper end and a tapered lower end. It generates high-speed swirling flow by relying on the tangential inlet formed by multiple connecting channels (9) on the wall surface, thereby enabling the lubricating oil that has passed through the first oil-gas separation chamber (21) to enter the second oil-gas separation chamber (22) for further separation by relying on the tangential inlet formed by multiple connecting channels (9).

9. The two-stage oil-gas separator as described in claim 8, characterized in that, The height of the vortex chamber (6) is 3~6mm; the axial angle between the connecting channel (9) and the wall of the inner cylinder (7) is 30°~60°.

10. A method for oil-gas separation in a two-stage oil-gas separator as described in claims 1-9, characterized in that, Includes the following steps: The high-temperature lubricating oil drawn back from various parts of the engine by the return oil pump forms an oil-gas mixture due to continuous suction. The oil-gas mixture enters the first oil-gas separation chamber (21) tangentially through the return oil port (4) and accumulates at the bottom of the first oil-gas separation chamber (21). Under the action of inertia, it gradually spirals upward inside the first oil-gas separation chamber (21). At this time, the oil-gas mixture inside the first oil-gas separation chamber (21) is affected by centrifugal force. The denser lubricating oil is thrown towards the inner wall of the outer cylinder (2) and spirals up along the outer wall of the inner cylinder (7). After the oil-gas mixture reaches the top of the first oil-gas separation chamber (21), it enters the second oil-gas separation chamber (22) tangentially through multiple connecting channels 9. At the same time, the less dense gas, under the action of centrifugal force and centripetal force, gathers towards the center and spirals up along the outer wall of the inner cylinder (7) in the first oil-gas separation chamber (21). After reaching the top of the first oil-gas separation chamber (21), it enters the ventilation pipe (1) through the air hole (8) and is discharged through the ventilation pipe (1). However, at this time, the lubricating oil and gas in the oil-gas mixture cannot be completely separated after one oil-gas separation. Therefore, in the second oil-gas separation chamber (22), the oil-gas mixture after the first separation will be separated again. Inside the second oil-gas separation chamber (22), under the action of centrifugal force, the denser lubricating oil is thrown towards the inner wall of the inner cylinder (7), and under the action of gravity and inertia, it spirals down along the inner wall of the inner cylinder (7), and after reaching the bottom of the second oil-gas separation chamber (22), it flows into the cavity of the base (3), and then flows back to the lubricating oil tank through the oil supply port (5) on the side of the base (3); at the same time, the less dense gas, under the action of centrifugal force and centripetal force, gathers towards the center, and under the action of inertia, it moves along the axial direction of the inner cylinder (7) towards the ventilation pipe (1), and when it reaches the opening of the ventilation pipe (1), it enters the ventilation pipe (1) and is discharged through the ventilation pipe (1).

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