A centrifugal oil-gas separation device

Abstract

The present invention discloses a centrifugal oil-gas separation device, which includes a housing, a separation component, an internal circulation component and a sleeve. The separation component includes a main shaft, a lower pressing housing and a plurality of discs. An internal circulation gap is formed between the internal circulation component and the lower pressing housing; the sleeve is arranged on the inner wall of the housing, and a reflux channel is formed inside the sleeve or between the sleeve and the inner wall of the housing. A plurality of reflux holes communicating with the reflux channel are arranged on the inner peripheral wall of the sleeve, and a gap is left between the inner peripheral wall of the sleeve and the edge of the separation component. The top of the reflux channel is sealed, and the bottom of the reflux channel has an opening facing the bottom of the housing. Part of the gas and / or oil-gas mixture discharged from the radial channel flows through the reflux holes, the reflux channel and the internal circulation gap in sequence, and then flows to the axial channel again. By setting the sleeve to construct an internal circulation channel, the centrifugal oil-gas separation device enables part of the gas and / or oil-gas mixture to reflux for secondary separation, promotes flow balance, and significantly enhances the oil-gas separation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal separation, and particularly relates to a centrifugal oil-gas separation device. Background Art

[0002] The oil-gas separator is a main component in the crankcase ventilation system, which efficiently separates the engine oil in the crankcase blow-by gas. Its separation performance has an important impact on the reliability and emissions of the engine.

[0003] The working principle of the active centrifugal oil-gas separator is to form a rotating eddy current in the separator, so that the particles in the mixed gas flow are separated under the action of centrifugal force. A plurality of conical discs are installed on the rotating shaft of the active centrifugal separator, and through holes are opened at the positions of the discs close to the rotating shaft, which are the flow channels for the mixed gas. When the rotating shaft moves, the mixed gas will be thrown out along the annular space between the conical discs under the action of centrifugal force, achieving the purpose of oil-gas separation.

[0004] In the prior art, when the oil-gas mixture enters the housing, under the influence of inertia and the smoothness of the flow channel, a large amount of the oil-gas mixture will enter the annular space between the discs in the upper half layer, and a small amount of the oil-gas mixture will enter the annular space between the discs in the lower half layer. Due to the unbalanced flow rate distribution, the large amount of oil-gas mixture in the annular space between the discs in the upper half layer cannot be effectively separated, thus affecting the final oil-gas separation effect. Summary of the Invention

[0005] The purpose of the present invention is to provide a centrifugal oil-gas separation device, which is used to send part of the discharged gas and / or oil-gas mixture into the separator for forced internal circulation to achieve re-separation, promote flow balance, and thus improve the oil-gas separation effect.

[0006] The purpose of the present invention is achieved by the following technical solutions: A centrifugal oil-gas separation device, comprising:

[0007] A housing, an oil-gas inlet and an oil return port are provided on the housing near the bottom, and an air outlet is provided on the housing near the top;

[0008] A separation component, including a main shaft, a lower pressing housing and a plurality of discs. At least a part of the main shaft is rotatably arranged in the housing. The plurality of discs are stacked on the main shaft and form an axial flow channel extending along the main shaft direction and a radial flow channel located between adjacent two discs. The lower pressing housing is arranged on the main shaft and is located below the plurality of discs. The oil-gas mixture input from the oil-gas inlet sequentially flows through the axial flow channel and the radial flow channel, and gas and oil liquid are separated under the centrifugal action of the separation component. The separated oil liquid is discharged through the oil return port;

[0009] An inner circulation component is arranged inside the housing and below the pressing housing, and an inner circulation gap is formed between the inner circulation component and the pressing housing;

[0010] A sleeve is arranged on the inner wall of the housing. A return flow channel is formed inside the sleeve or between the sleeve and the inner wall of the housing. A plurality of return holes communicating with the return flow channel are arranged on the inner peripheral wall of the sleeve, and a gap is left between the inner peripheral wall of the sleeve and the edge of the separation component. The top of the return flow channel is sealed, and the bottom of the return flow channel has an opening facing the bottom of the housing. Part of the gas and / or oil-gas mixture discharged from the radial flow channel flows through the return holes, the return flow channel and the inner circulation gap in sequence and then flows back to the axial flow channel again.

[0011] In an alternative embodiment, the distribution density of the plurality of return holes on the inner peripheral wall near the top of the sleeve is greater than the distribution density on the inner peripheral wall near the bottom of the sleeve. The beneficial effect of this technical solution is that by setting the density of the return holes, the density of the return holes near the top of the sleeve is greater than that near the bottom of the sleeve, which can specifically control the flow rate of the gas and / or oil-gas mixture entering the return flow channel, and always keep the flow rate of the upper half of the separation component greater than that of the lower half, so that more gas and / or oil-gas mixture in the upper half can be separated for the second time, thereby ensuring the oil separation effect.

[0012] In an alternative embodiment, in the direction from the top to the bottom of the sleeve, the distribution density of the return holes gradually decreases. The beneficial effect of this technical solution is that according to the separation effect of each layer of radial flow channels, the flow rate of the gas and / or oil-gas mixture introduced into the return flow channel from top to bottom also gradually decreases, so as to more accurately separate the oil-gas mixture at different positions for the second time, further enhancing the oil separation effect.

[0013] In an alternative embodiment, the plurality of return holes are evenly distributed on the inner peripheral wall of the sleeve, and the aperture of the return holes on the inner peripheral wall near the top of the sleeve is larger than the aperture of the return holes on the inner peripheral wall near the bottom of the sleeve. The beneficial effect of this technical solution is that by setting the aperture of the return holes, the aperture of the return holes near the top of the sleeve is larger than that near the bottom of the sleeve, which can also control the flow rate of the gas and / or oil-gas mixture entering the return flow channel, and always keep the flow rate of the upper half of the separation component greater than that of the lower half, so that more gas and / or oil-gas mixture in the upper half can be separated for the second time, thereby ensuring the oil separation effect.

[0014] In an alternative embodiment, in the direction from the top to the bottom of the sleeve, the aperture diameter of the return holes gradually decreases. The beneficial effect of this technical solution is that this design can also gradually reduce the flow rate of the gas and / or the oil-gas mixture introduced into the return flow channel from top to bottom, so as to more accurately perform secondary separation of the oil-gas mixture at different positions, and further enhance the effect of oil separation.

[0015] In an alternative embodiment, a plurality of the return holes are only distributed on the inner peripheral wall of the upper half of the sleeve. The beneficial effect of this technical solution is that by providing return holes on the inner peripheral wall of the upper half of the sleeve, part of the gas and / or the oil-gas mixture separated in the upper half can be introduced into the return flow channel, and secondary separation can be achieved by using the constructed internal circulation flow channel, thereby enhancing the effect of oil separation.

[0016] In an alternative embodiment, the return holes have a notch shape on the inner peripheral wall of the sleeve that is consistent with the flow direction of the gas and / or the oil-gas mixture discharged from most of the radial flow channels. The beneficial effect of this technical solution is that by designing the return holes into a notch shape that is consistent with the flow direction of the gas and / or the oil-gas mixture, it is more conducive for the gas and / or the oil-gas mixture to enter the return flow channel, enabling more gas and / or oil-gas mixture to be secondarily separated, thereby improving the separation effect.

[0017] In an alternative embodiment, the disc is in the shape of a hollow frustum, and an annular throttle rib is provided on the outer side wall of the disc. The throttle rib is a continuous or discontinuous structure. The beneficial effect of this technical solution is that by providing the throttle rib, it has the effect of promoting the residence of the oil-gas mixture in the radial flow channel, enabling the oil-gas mixture to have sufficient time to be separated. At the same time, the cross-section of the throttle rib is triangular, which acts like a springboard between the discs, guiding the oil-gas mixture to collide with the discs, and thereby separating the oil, which can significantly improve the effect of oil-gas separation.

[0018] In an alternative embodiment, in the direction from top to bottom of the main shaft, the throttling effect of the throttle ribs on the disc on the oil-gas mixture gradually decreases. The beneficial effect of this technical solution is that by setting the throttle ribs, the throttling effect of the throttle ribs on the disc on the oil-gas mixture gradually decreases from top to bottom, which can make the flow rates of the radial flow channels at each layer tend to be balanced, and thereby significantly improve the utilization rate and separation efficiency of the separation component.

[0019] In an alternative embodiment, a plug-in member is provided at the oil-gas inlet and / or the gas outlet. The plug-in member is used to separate some of the oil in the oil-gas mixture. The beneficial effect of this technical solution is as follows: The plug-in member at the oil-gas inlet is used for the initial filtration of the oil in the oil-gas mixture. Specifically, when the oil-gas mixture enters from the oil-gas inlet, it will first collide with the plug-in member. Some of the oil will agglomerate on the plug-in member here to form large-particle-size oil and then be separated, thus playing the role of initially filtering the oil in the oil-gas mixture. Preferably, the plug-in member located at the oil-gas inlet has an arc-shaped structure, which can also play a guiding role for the oil-gas mixture while separating some of the oil, enabling the oil-gas mixture to enter the separation component in a swirling manner and improving the subsequent oil-gas separation effect. The plug-in member at the gas outlet is used for the final filtration of the oil in the oil-gas mixture. Specifically, when the gas is discharged from the gas outlet, a small amount of oil remaining in the gas will collide with the plug-in member here and be separated after agglomerating to form large-particle-size oil, ensuring the purity of the discharged gas and reducing oil consumption. In addition, the plug-in members at the oil-gas inlet and the gas outlet can also increase the flow rate of the oil-gas mixture, thereby increasing the pressure rise between the gas outlet and the oil-gas inlet. A higher pressure rise can ensure a larger negative pressure in the crankcase connected to the centrifugal oil-gas separation device, making it difficult for the oil and gas to overflow and having high reliability.

[0020] Compared with the prior art, the beneficial effects of the present invention at least include: By providing a sleeve to construct an internal circulation flow path, enabling some of the gas and / or oil-gas mixture to flow back for secondary separation, promoting flow balance, and significantly enhancing the oil-gas separation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective view of the centrifugal oil-gas separation device according to an embodiment of the present invention.

[0022] Figure 2 is a top view of the centrifugal oil-gas separation device according to an embodiment of the present invention.

[0023] Figure 3 is Figure 2 a sectional view along line A-A.

[0024] Figure 4 is a schematic structural view of the housing according to an embodiment of the present invention.

[0025] Figure 5a is Figure 4 the first sectional view along line B-B when there is no separation component in the middle housing.

[0026] Figure 5b is Figure 4 the second sectional view along line B-B when there is no separation component in the middle housing.

[0027] Figure 5c isFigure 4 The third sectional view along line B-B without a separation component in the middle housing.

[0028] Figure 6 It is a perspective view of the separation component of an embodiment of the present invention.

[0029] Figure 7 It is a schematic structural view of the disc of an embodiment of the present invention.

[0030] Figure 8 It is Figure 4 The sectional view along line C-C.

[0031] Figure 9 It is Figure 4 The sectional view along line D-D.

[0032] Figure 10 It is a schematic diagram of the force analysis of the droplets on the disc.

[0033] Figure 11 It is a schematic diagram of the oil and gas flow when the oil and gas inlet and the gas outlet are respectively arranged on the upper and lower sides of the housing.

[0034] In the figure: 1. Housing; 11. Oil and gas inlet; 12. Gas outlet; 2. Separation component; 21. Main shaft; 22. Lower pressing housing; 23. Disc; 3. Inner circulation part; 31. Cyclone; 311. Archimedes spiral flow channel; 32. Impeller; 4. Sleeve; 41. Return hole; 5. Inner circulation gap; 6. Return flow channel; 7. Throttle rib; 8. Connector. Specific embodiments

[0035] Now, the exemplary embodiments will be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be more complete and comprehensive, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and thus their repeated description will be omitted.

[0036] The words expressing position and direction described in the present invention are all illustrated by taking the accompanying drawings as examples, but can be changed according to needs, and all the changes made are included in the protection scope of the present invention.

[0037] See Figures 1-3 As shown, the present invention provides a centrifugal oil and gas separation device, including a housing 1, a separation component 2, an inner circulation part 3 and a sleeve 4.

[0038] An oil and gas inlet 11 and an oil return port (not shown in the figure) are provided on the housing 1 near the bottom, and a gas outlet 12 is provided on the housing 1 near the top.

[0039] The separation component 2 includes a main shaft 21, a lower pressing housing 22, and a plurality of discs 23. At least a part of the main shaft 21 is rotatably arranged in the housing 1. The plurality of discs 23 are stacked on the main shaft 21 and form an axial flow channel extending along the direction of the main shaft 21 and a radial flow channel located between two adjacent discs 23 (see Figure 6 as shown). The lower pressing housing 22 is arranged on the main shaft 21 and is located below the plurality of discs 23. The oil-gas mixture input from the oil-gas inlet 11 sequentially flows through the axial flow channel and the radial flow channel, and gas and oil are separated under the centrifugal action of the separation component 2. The separated oil is discharged through the oil return port.

[0040] The inner circulation component 3 is arranged in the housing 1 and is located below the lower pressing housing 22. An inner circulation gap 5 is formed between the inner circulation component 3 and the lower pressing housing 22.

[0041] The sleeve 4 is arranged on the inner wall of the housing 1. A return flow channel 6 is formed inside the sleeve 4 or between the sleeve 4 and the inner wall of the housing 1. A plurality of return holes 41 communicating with the return flow channel 6 are arranged on the inner peripheral wall of the sleeve 4. And a gap is left between the inner peripheral wall of the sleeve 4 and the edge of the separation component 2. The top of the return flow channel 6 is sealed, and the bottom of the return flow channel 6 has an opening facing the bottom of the housing 1. Part of the gas and / or oil-gas mixture discharged from the radial flow channel sequentially passes through the return holes 41, the return flow channel 6, and the inner circulation gap 5 and then flows back to the axial flow channel again.

[0042] The above structure constructs an inner circulation flow channel by adding the sleeve 4, so that part of the gas and / or oil-gas mixture can flow back to achieve secondary separation, promote flow balance, and further enhance the oil separation effect.

[0043] In the present invention, the rotational speed of the main shaft 21 can be 6500 - 7500 revolutions per minute, for example, 7000 revolutions per minute. Compared with the existing rotational speed of up to 10,000 revolutions per minute, by reducing the rotational speed, the damage to the bearings supporting the main shaft 21 can be significantly reduced, and the reliability of the centrifugal oil-gas separation device can be significantly improved. The number of discs 23 of the separation component 2 can be 15 - 30, preferably 20 - 25. Compared with the existing number of discs 23 of 40 - 50, by reducing the number of discs 23, the volume and cost of the centrifugal oil-gas separation device can be reduced, enabling the centrifugal oil-gas separation device to be assembled on more types of engines, and reducing the number of discs 23 can also reduce the weight of the separation component 2 and reduce the damage to the bearings.

[0044] However, simply reducing the rotational speed of the main shaft 21, decreasing the number of discs 23, and increasing the size of the separation space between the discs 23 will all lead to a decrease in separation efficiency to varying degrees. It will also cause a decrease in the pressure rise between the gas outlet 12 and the oil-gas inlet 11 of the centrifugal oil-gas separation device, thereby reducing the negative pressure in the crankcase, making it easy for oil and gas to overflow and reducing the reliability. Among them, the decrease in separation efficiency is mainly due to the phenomenon of flow imbalance.

[0045] Specifically, in the existing situation of a large number of discs 23 and a small separation space between the discs 23, the air flow resistance between the discs 23 is large, and the oil-gas mixture is more likely to pass evenly through the separation space between the discs 23 in the up and down directions, and the phenomenon of flow imbalance is not obvious. When the number of discs 23 is reduced and the separation space between the discs 23 is increased, as Figure 11 shown, when the oil-gas mixture flows upward from bottom to top through the axial flow channels of the stacked discs 23, under the action of flow inertia, the oil-gas mixture tends to flow out through the separation space between the discs 23 closer to the upper part. This results in a large flow rate of the oil-gas mixture between the discs 23 closer to the upper part and a small flow rate of the oil-gas mixture between the discs 23 closer to the lower part, causing the phenomenon of flow imbalance to become prominent. The direct result of flow imbalance is that the residence time of small droplets (about 1 μm) of the oil in the oil-gas mixture between the discs 23 closer to the upper part on the discs 23 is shortened, resulting in the small droplets being unable to agglomerate into large droplets, making it easier for the small droplets to be discharged from the centrifugal oil-gas separation device with the gas, ultimately leading to a decrease in separation efficiency.

[0046] More specifically, referring to Figure 10 Figure 10 is a schematic diagram of the force analysis of the droplets on the disc 23. The droplets on the disc 23 are subjected to the drag force and inertial force towards the lower edge of the disc 23 and the pressure gradient force towards the upper edge of the disc 23. When the resultant force of the pressure gradient force and the drag force and inertial force tends to be positive, the droplets tend to stay on the disc 23.

[0047] The drag force Fd is

[0048] where Cd is the drag coefficient of the droplet, ρ is the density of the gas phase, vs = v - vp is the difference between the gas velocity and the oil droplet velocity, v is the instantaneous velocity of the gas phase, vp is the instantaneous velocity of the oil droplet, and Ap is the projected area of the droplet.

[0049] ​It can be seen that the drag force is the thrust / resistance of the gas phase on the liquid droplet, and its direction depends on whether the liquid droplet is lower / higher than the gas phase velocity. The drag force on the liquid droplet on the disc 23 is outward and is proportional to the projected area of the liquid droplet. The smaller the radial velocity of the gas flow, the smaller the drag force, which is more conducive to the retention of the liquid droplet; conversely, the escape of the liquid droplet increases. When the flow rate is unbalanced, the flow rate of the oil in the oil-gas mixture between the discs 23 near the upper part increases, the drag force increases, the liquid droplets accelerate to escape, and the separation efficiency decreases.

[0050] The inertial force F MRF is F MRF = m p [ω×(ω×r)+2(ω×V p )].

[0051] Among them, mp is the mass of the liquid droplet, ω is the angular velocity vector of the rotating reference coordinate system, r is the distance vector to the rotation axis, and Vp is the volume of the liquid droplet.

[0052] The inertial force includes the centrifugal force and the Coriolis force (geostrophic deflection force). The inertial force on the liquid droplet on the disc 23 is outward and to the left, proportional to the mass of the liquid droplet. As the particle size decreases and the turbulent dissipation increases, the influence of the inertial force weakens.

[0053] The pressure gradient force Fp is

[0054] Among them, Vp is the volume of the liquid droplet, is the gradient of the static pressure in the gas phase.

[0055] The pressure gradient force can be understood as a generalized buoyancy force. The pressure gradient force on the liquid droplet on the disc 23 is inward, proportional to the volume of the oil droplet. A large pressure gradient is likely to appear on the outer periphery of the disc 23, and its value depends on the rotation speed and the flow guiding structure. When the pressure gradient force increases and the drag force decreases to the critical point, the liquid droplets appear suspended, forming a concentrated area, the residence time increases, and the agglomeration effect is enhanced.

[0056] From the above analysis, it can be seen that for a centrifugal oil-gas separation device using a large number of discs 23 and a small separation space of the discs 23, how to improve the structure of the centrifugal oil-gas separation device to make the flow rate of the oil-gas mixture between the discs 23 tend to be balanced, and then increase the residence time of small liquid droplets about 1μm on the discs 23 is the key to improving the separation efficiency.

[0057] In the present invention, in order to keep the centrifugal oil-gas separation device having a separation efficiency comparable to that of the existing centrifugal oil-gas separation device with a high rotation speed of the rotating shaft, a large number of discs 23 and a small separation space of the discs 23 under the conditions of reducing the rotation speed of the rotating shaft, reducing the number of discs 23 and increasing the separation space of the discs 23, a series of improvements have been made to the centrifugal oil-gas separation device.

[0058] Specifically, an inner circulation flow path is constructed by adding a sleeve 4. During the operation of the centrifugal oil-gas separation device, a part of the gas and / or oil-gas mixture separated from the disc 23 is directly discharged from the gas outlet 12, and the other part can enter the return flow path 6 through the return holes 41. Since a relatively low-pressure environment is formed in the lower region of the separation component 2 relative to its outer peripheral region during high-speed rotation, that is, the region formed by the lower part of the separation component 2 and the inner circulation member 3 is also in a relatively low-pressure environment relative to the bottom region of the return flow path 6. Therefore, the gas and / or oil-gas mixture entering the return flow path 6 will flow back into the lower region of the separation component 2 under the action of air pressure, enter the radial flow path again through the axial flow path, and be secondarily separated under the action of centrifugal force. On the one hand, it enables some incompletely separated oil-gas mixtures to pass through between the discs 23 multiple times for separation, increasing the residence time of the droplets on the discs 23. On the other hand, by forming an inner circulation flow of the oil-gas mixture, some of the oil-gas mixture between the multiple discs 23 near the upper part participates in the inner circulation again, which is beneficial to increasing the flow rate of the oil-gas mixture between the multiple discs 23 near the lower part and promoting flow balance. As a result, under the preconditions of low rotational speed, few discs 23, and large gaps between the discs 23, the centrifugal oil-gas separation device can still maintain a high separation efficiency. In addition, the gas and / or oil-gas mixture entering the return flow path 6 is less affected by the gas and / or oil-gas mixture ejected between the discs 23, and the gas and / or oil-gas mixture is more likely to flow downward. Therefore, the inner circulation flow is smoother, thus more effectively promoting flow balance.

[0059] See Figure 4 、 Figure 5a As shown in the figure, in a specific embodiment, multiple return holes 41 are only distributed on the inner peripheral wall of the upper half of the sleeve 4.

[0060] From Figure 3 、 Figure 6 it can be seen that the caliber of the axial flow path of the separation component 2 is large and the gap of the radial flow path is small. Under the influence of inertia and the smoothness of the flow path, the flow rate of the oil-gas mixture passing through each radial flow path also decreases from top to bottom, resulting in the oil-gas mixture being concentrated in the upper half of the separation component 2, and the separation effect of the upper half of the separation component 2 is correspondingly poor. By arranging the return holes 41 on the inner peripheral wall of the upper half of the sleeve 4, the above structure can introduce some of the gas and / or oil-gas mixture separated from the upper half into the return flow path 6, and realize secondary separation by using the constructed inner circulation flow path, strengthening the oil-liquid separation effect.

[0061] See Figure 4 、 Figure 5bAs shown, in a preferred embodiment, the distribution density of the plurality of return holes 41 on the inner peripheral wall near the top of the sleeve 4 is greater than that on the inner peripheral wall near the bottom of the sleeve 4.

[0062] Since the flow rate through each radial flow channel decreases from top to bottom, the effect of oil-gas separation also decreases from top to bottom. By setting the density of the return holes 41, the density of the return holes 41 near the top of the sleeve 4 is greater than that near the bottom of the sleeve 4, which can specifically control the flow rate of the gas and / or oil-gas mixture entering the return flow channel 6, and always keep the flow rate of the upper half of the separation component 2 greater than that of the lower half, so that more gas and / or oil-gas mixture in the upper half can be secondarily separated, thereby ensuring the effect of oil-liquid separation.

[0063] Preferably, in the direction from the top to the bottom of the sleeve 4, the distribution density of the return holes 41 gradually decreases. This design enables the flow rate of the gas and / or oil-gas mixture introduced into the return flow channel 6 from top to bottom to also gradually decrease according to the separation effect of each layer of radial flow channels, so as to more precisely secondarily separate the oil-gas mixture at different positions and further enhance the effect of oil-liquid separation.

[0064] See Figure 4 、 Figure 5c As shown, in another preferred embodiment, the plurality of return holes 41 are evenly distributed on the inner peripheral wall of the sleeve 4, and the aperture of the return holes 41 on the inner peripheral wall near the top of the sleeve 4 is larger than the aperture of the return holes 41 on the inner peripheral wall near the bottom of the sleeve 4.

[0065] Similar to controlling the distribution density of the return holes 41, by setting the aperture of the return holes 41, the aperture of the return holes 41 near the top of the sleeve 4 is larger than the aperture of the return holes 41 near the bottom of the sleeve 4, which can also control the flow rate of the gas and / or oil-gas mixture entering the return flow channel 6, and always keep the flow rate of the upper half of the separation component 2 greater than that of the lower half, so that more gas and / or oil-gas mixture in the upper half can be secondarily separated, thereby ensuring the effect of oil-liquid separation.

[0066] Preferably, in the direction from the top to the bottom of the sleeve 4, the aperture of the return holes 41 gradually decreases. This design can also make the flow rate of the gas and / or oil-gas mixture introduced into the return flow channel 6 from top to bottom gradually decrease, so as to more precisely secondarily separate the oil-gas mixture at different positions and further enhance the effect of oil-liquid separation.

[0067] In a specific embodiment, the return holes 41 on the inner peripheral wall of the sleeve 4 have a notch shape consistent with the flow direction of the gas and / or oil-gas mixture discharged from most of the radial flow channels.

[0068] By designing the reflux hole 41 into a notch shape consistent with the flow direction of the gas and / or oil-gas mixture, it is more conducive to the gas and / or oil-gas mixture entering the reflux channel 6, enabling more gas and / or oil-gas mixture to be secondarily separated, thereby improving the separation effect.

[0069] In a specific embodiment, an oil-repellent layer is provided on the inner peripheral wall of the sleeve 4 and / or the inner wall of the housing 1.

[0070] After the oil-repellent layer is provided, it is not only conducive to the small particle oil liquid after separation to slide and converge to form large particle oil liquid, improving the reflux rate of the oil liquid, but also can prevent the oil liquid from adhering to the inner wall to form oil sludge. In this embodiment, the oil-repellent layer is preferably one of a polyolefin layer, a polycarbonate layer, a polyamide layer, a polyacrylonitrile layer, a fluorine-free acrylate layer, a molten paraffin layer, a perfluoropolyether layer, a polytetrafluoroethylene layer, a polyperfluoroethylene-propylene layer, a tetrafluoroethylene copolymer layer, a polyvinylidene fluoride layer, and a soluble tetrafluoroethylene layer. The oil-repellent layers of the above materials not only have a high oil return rate but also do not react with the oil liquid and have long-term reliability.

[0071] See Figures 6-7 As shown, in a specific embodiment, the disc 23 has a hollow frustum structure, and an annular throttle rib 7 is provided on the outer side wall of the disc 23. The throttle rib 7 is a continuous or discontinuous structure.

[0072] The above structure has the function of promoting the residence of the oil-gas mixture in the radial channel by setting the throttle rib 7, enabling the oil-gas mixture to have sufficient time to be separated. At the same time, the cross-section of the throttle rib 7 is triangular, playing a role similar to a springboard between the discs 23, guiding the oil-gas mixture to collide with the disc 23, and thus separating the oil liquid, which can significantly improve the oil-gas separation effect.

[0073] In a preferred embodiment, in the direction from top to bottom of the main shaft 21, the throttling effect of the throttle rib 7 on the oil-gas mixture on the disc 23 gradually decreases.

[0074] Referring to the above, the main part of the separation component 2 actually participating in the oil-gas separation is the upper half, and only a small amount or even no participation in the oil-gas separation treatment is involved in the lower half of the separation component 2. In this embodiment, by setting the throttle rib 7, the throttling effect of the throttle rib 7 on the oil-gas mixture on the disc 23 gradually decreases from top to bottom, which can make the flow rates of the radial channels of each layer tend to be balanced, and thus significantly improve the utilization rate and separation efficiency of the separation component 2. Specifically, the following several methods (not shown in the figure) can be adopted:

[0075] In the direction from top to bottom of the main shaft 21, the height of the throttle rib 7 on the disc 23 gradually decreases; or,

[0076] In the direction from top to bottom of the main shaft 21, the number of through holes on the throttle ribs 7 of the disc 23 gradually increases; or,

[0077] In the direction from top to bottom of the main shaft 21, the aperture of the through holes on the throttle ribs 7 of the disc 23 gradually increases; or,

[0078] The throttle ribs 7 have a discontinuous structure, and in the direction from top to bottom of the main shaft 21, the distance between the rib segments of the throttle ribs 7 of the disc 23 gradually increases; or,

[0079] In the direction from top to bottom of the main shaft 21, the number of the throttle ribs 7 of the disc 23 gradually decreases.

[0080] The above several throttle rib 7 schemes can all make the throttling effect of the separation component 2 gradually decrease from top to bottom, so as to ensure that the flow rates of the radial flow channels tend to be balanced, and significantly improve the utilization rate and separation efficiency of the separation component 2.

[0081] Still referring to Figure 3 and Figure 8 shown, in a specific embodiment, the internal circulation member 3 includes a cyclone 31, and the cyclone 31 is arranged between the oil and gas inlet 11 and the separation component 2. The cyclone 31 is used to pressurize the oil and gas mixture and strengthen the swirling effect.

[0082] After the above structure is provided with the cyclone 31, the oil and gas mixture input into the cyclone 31 from the oil and gas inlet 11 will enter the separation component 2 in a swirling manner. During this process, part of the oil liquid will be separated from the oil and gas mixture by colliding with the cyclone 31. At the same time, the cyclone 31 will pressurize the oil and gas mixture and strengthen its swirling effect, so that the oil and gas mixture can obtain a better centrifugal separation effect after entering the separation component 2. To better guide the oil and gas mixture into the cyclone 31, as Figure 8 shown, an Archimedean spiral flow channel 311 can also be arranged between the cyclone 31 and the oil and gas inlet 11. By adopting the Archimedean spiral flow channel 311, not only the separation efficiency is high, but also the air flow can be accelerated, and a better pressurizing effect can be achieved. Under the conditions of reducing the rotation speed of the main shaft 21, reducing the number of discs 23 and increasing the gap of the discs 23, the pressurizing effect of the above structure can keep a relatively high pressure rise between the air outlet 12 and the oil and gas inlet 11 of the centrifugal oil and gas separation device.

[0083] The internal circulation member 3 can also include an impeller 32. The impeller 32 is arranged on the main shaft 21, and the impeller 32 is located between the cyclone 31 and the separation component 2. The impeller 32 is used to pressurize the oil and gas mixture and strengthen the swirling effect.

[0084] By adding an impeller 32 on the basis of the cyclone 31, when the main shaft 21 drives the impeller 32 to rotate, the impeller 32 will also collide with the oil-gas mixture to separate part of the oil liquid, and at the same time pressurize and disturb the oil-gas mixture, so that the originally swirling oil-gas mixture can enter the separation component 2 with a higher-speed swirl, thereby further improving the centrifugal separation effect. In addition, the pressurizing effect of the impeller 32 can also increase the pressure rise between the air outlet 12 and the oil-gas inlet 11. With a higher pressure rise, it can ensure a larger negative pressure in the crankcase (not shown in the figure) connected to the centrifugal oil-gas separation device, making it difficult for the oil liquid and gas to overflow, and having high reliability.

[0085] See Figure 4 、 Figures 8-9 As shown, in a specific embodiment, a plug-in member 8 is provided at the oil-gas inlet 11 and / or the air outlet 12, and the plug-in member 8 is used to separate part of the oil liquid in the oil-gas mixture.

[0086] In the above structure, the plug-in member 8 at the oil-gas inlet 11 is used for initially filtering the oil liquid in the oil-gas mixture. Specifically, when the oil-gas mixture enters from the oil-gas inlet 11, it will first collide with the plug-in member 8, and part of the oil liquid will agglomerate on the plug-in member 8 here to form large-particle-size oil liquid and then be separated, thereby playing the role of initially filtering the oil liquid in the oil-gas mixture. Preferably, the plug-in member 8 located at the oil-gas inlet 11 is of an arc structure, which can also play a guiding role for the oil-gas mixture while separating part of the oil liquid, so that the oil-gas mixture enters the separation component 2 in a swirling manner, improving the subsequent oil-gas separation effect. The plug-in member 8 at the air outlet 12 is used for finally filtering the oil liquid in the oil-gas mixture. Specifically, when the gas is discharged from the air outlet 12, the small amount of oil liquid remaining in the gas will collide with the plug-in member 8 here and be separated after agglomerating to form large-particle-size oil liquid, ensuring the purity of the discharged gas and reducing the oil consumption.

[0087] In addition, the plug-in members 8 at the oil-gas inlet 11 and the air outlet 12 can also increase the flow rate of the oil-gas mixture, thereby increasing the pressure rise between the air outlet 12 and the oil-gas inlet 11. With a higher pressure rise, it can ensure a larger negative pressure in the crankcase connected to the centrifugal oil-gas separation device, making it difficult for the oil liquid and gas to overflow, and having high reliability.

[0088] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Without departing from the principle and purpose of the present invention, those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the invention, and all these changes should fall within the protection scope of the claims of the present invention.

Claims

1. A centrifugal oil-gas separation device, characterized in that, Comprising: A housing, an oil-gas inlet and an oil return port are provided on the housing near the bottom, and an air outlet is provided on the housing near the top; A separation assembly, including a main shaft, a lower pressing housing and a plurality of discs. At least a part of the main shaft is rotatably arranged in the housing. The plurality of discs are stacked on the main shaft and form an axial flow channel extending in the direction of the main shaft and a radial flow channel located between adjacent two discs. The lower pressing housing is arranged on the main shaft and is located below the plurality of discs. The oil-gas mixture input from the oil-gas inlet sequentially flows through the axial flow channel and the radial flow channel, and gas and oil liquid are separated under the centrifugal action of the separation assembly. The separated oil liquid is discharged through the oil return port; An inner circulation member, which is arranged in the housing and is located below the lower pressing housing. An inner circulation gap is formed between the inner circulation member and the lower pressing housing; A sleeve, which is arranged on the inner wall of the housing. A return flow channel is formed inside the sleeve or between the sleeve and the inner wall of the housing. A plurality of return holes communicating with the return flow channel are provided on the inner peripheral wall of the sleeve, and a gap is left between the inner peripheral wall of the sleeve and the edge of the separation assembly. The top of the return flow channel is sealed, and the bottom of the return flow channel has an opening facing the bottom of the housing. Part of the gas and / or oil-gas mixture discharged from the radial flow channel sequentially passes through the return holes, the return flow channel and the inner circulation gap, and then flows back to the axial flow channel again.

2. The centrifugal oil-gas separation device according to claim 1, wherein, The distribution density of the plurality of return holes on the inner peripheral wall near the top of the sleeve is greater than that on the inner peripheral wall near the bottom of the sleeve.

3. The centrifugal oil-gas separation device according to claim 2, characterized in that In the direction from the top to the bottom of the sleeve, the distribution density of the return holes gradually decreases.

4. The centrifugal oil-gas separation device according to claim 1, wherein, The plurality of return holes are evenly distributed on the inner peripheral wall of the sleeve, and the aperture of the return holes on the inner peripheral wall near the top of the sleeve is larger than the aperture of the return holes on the inner peripheral wall near the bottom of the sleeve.

5. The centrifugal oil-gas separation device according to claim 4, characterized in that In the direction from the top to the bottom of the sleeve, the aperture of the return holes gradually decreases.

6. The centrifugal oil-gas separation device according to claim 1, characterized in that The plurality of return holes are only distributed on the inner peripheral wall of the upper half of the sleeve.

7. The centrifugal oil-gas separation device according to claim 1, characterized in that, The return holes have a notch shape on the inner peripheral wall of the sleeve that is consistent with the flow direction of the gas and / or oil-gas mixture discharged from most of the radial flow channels.

8. The centrifugal oil-gas separation device according to claim 1, wherein The disc has a hollow frustum structure, and an annular throttling rib is provided on the outer side wall of the disc. The throttling rib is a continuous or discontinuous structure.

9. The centrifugal oil-gas separation device according to claim 8, wherein, In the direction from the top to the bottom of the main shaft, the throttling effect of the throttling ribs on the disc on the oil-gas mixture gradually decreases.

10. The centrifugal oil-gas separation device according to claim 1, characterized in that, A plug-in member is provided at the oil-gas inlet and / or the air outlet, and the plug-in member is used for separating part of the oil liquid in the oil-gas mixture.

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