CN116116111A - A centrifugal oil-gas separation device - Google Patents

Abstract

The invention discloses a centrifugal oil-gas separation device, which comprises a shell, a separation assembly, an inner circulation piece and a sleeve, wherein the separation assembly comprises a main shaft, a lower pressing shell and a plurality of discs, and an inner circulation gap is formed between the inner circulation piece and the lower pressing shell; the sleeve is arranged on the inner wall of the shell, a backflow channel is formed in the sleeve or between the sleeve and the inner wall of the shell, a plurality of backflow holes communicated with the backflow channel are formed in the inner peripheral wall of the sleeve, a gap is reserved between the inner peripheral wall of the sleeve and the edge of the separation assembly, the top of the backflow channel is sealed, an opening facing the bottom of the shell is formed in the bottom of the backflow channel, and part of gas and/or oil gas mixture discharged from the radial channel flows to the axial channel again after sequentially passing through the backflow holes, the backflow channel and the inner circulation gap. The centrifugal oil-gas separation device constructs an internal circulation flow channel by arranging the sleeve, so that partial gas and/or oil-gas mixture flows back to realize secondary separation, flow balance is promoted, and the oil-gas separation effect is remarkably enhanced.

Description

A centrifugal oil-gas separation device

technical field

The invention relates to the technical field of centrifugal separation, in particular to a centrifugal oil-gas separation device.

Background technique

The oil-gas separator is the main component of the crankcase ventilation system, which efficiently separates the engine oil in the crankcase blow-by gas, and its separation performance has an important impact on the reliability and emission of the engine.

The working principle of the active centrifugal oil and gas separator is to form a rotating vortex in the separator, so that the particles in the mixed air flow are separated under the action of centrifugal force. A number of conical discs are installed on the rotating shaft of the active centrifugal separator. There are through holes in the position of the discs close to the rotating shaft, which is the circulation channel of the mixed gas. When the rotating shaft moves, the mixed gas will be under the action of centrifugal force. Throw it out along the annular space between the conical discs to achieve the purpose of oil and gas separation.

In the prior art, when the oil-air mixture enters the casing, under the influence of inertia and smoothness of the flow channel, a large amount of oil-air mixture will enter into the annular space between the upper half discs, and a small amount of oil-air mixture will enter into the In the annular space near the lower half of the discs, due to the unbalanced flow distribution, a large amount of oil-gas mixture in the annular space near the upper half of the discs cannot be effectively separated, which affects the final oil-gas separation effect.

Contents of the invention

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 realize re-separation, promote flow balance, and then improve the effect of oil-gas separation.

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

The housing, the housing near the bottom is provided with an oil gas inlet and an oil return port, and the housing near the top is provided with an air outlet;

The separation assembly includes a main shaft, a lower pressure shell and a plurality of discs, at least a part of the main shaft is rotatably arranged in the housing, and a plurality of the discs are stacked on the main shaft and formed to extend along the direction of the main shaft The axial flow channel and the radial flow channel located between two adjacent discs, the lower pressure shell is arranged on the main shaft and located below a plurality of the discs, the input from the oil and gas inlet The oil-gas mixture flows through the axial flow channel and the radial flow channel in sequence, and the gas and oil are separated under the centrifugal action of the separation component, and the separated oil is discharged through the oil return port;

An inner circulation part, arranged in the housing and below the lower pressure shell, an inner circulation gap is formed between the inner circulation part and the lower pressure shell;

The sleeve is arranged on the inner wall of the housing, and a return flow channel is formed in the sleeve or between the sleeve and the inner wall of the housing, and the inner peripheral wall of the sleeve is provided with communication There are a plurality of return holes in the return flow channel, and there is a gap 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 a Part of the gas and/or oil-air mixture discharged from the radial flow channel passes through the return hole, the return flow channel and the internal circulation gap in sequence, and then flows to the axial flow channel again.

In an optional solution, 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: by setting the density of the return holes, the density of the return holes near the top of the sleeve is greater than the density of the return holes near the bottom of the sleeve, and the gas and/or gas entering the return channel can be targeted. or the flow rate of the oil-gas mixture, and always keep the flow rate of the upper part of the separation assembly greater than the flow rate of the lower part, so that more gas and/or oil-gas mixture in the upper part can be separated for the second time, thereby ensuring oil The effect of liquid separation.

In an optional solution, in the direction from the top to the bottom of the sleeve, the distribution density of the return holes decreases gradually. The beneficial effect of this technical solution is: this design makes the flow rate of the gas and/or oil-gas mixture introduced into the return flow channel from top to bottom gradually decrease according to the separation effect of the radial flow channels of each layer, so that different positions can be more precisely The oil-gas mixture at the place is separated for the second time, which further strengthens the effect of oil-liquid separation.

In an optional solution, a plurality of the return holes are evenly distributed on the inner peripheral wall of the sleeve, and the diameter of the return holes on the inner peripheral wall near the top of the sleeve is larger than that near the The diameter of the return hole on the inner peripheral wall at the bottom of the sleeve. The beneficial effect of this technical solution is: by setting the aperture of the return hole, the aperture of the return hole near the top of the sleeve is larger than the aperture of the return hole near the bottom of the sleeve, and the gas and/or The flow rate of the oil-gas mixture is controlled, and the flow rate of the upper part of the separation component is always greater than that of the lower part, so that more gas and/or oil-gas mixture in the upper part can be separated for the second time, thereby ensuring oil separation effect.

In an optional solution, in the direction from the top to the bottom of the sleeve, the diameter of the return hole decreases gradually. The beneficial effect of this technical solution is: this design can also gradually reduce the flow rate of the gas and/or oil-gas mixture introduced into the return channel from top to bottom, so that the oil-gas mixture at different positions can be separated more accurately, further Enhance the effect of oil-liquid separation.

In an optional solution, the multiple 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: by setting the return hole on the inner peripheral wall of the upper part of the sleeve, part of the gas and/or oil-gas mixture separated in the upper part can be introduced into the return flow channel, and the internal circulation of the structure can be used. The flow channel realizes secondary separation to enhance the effect of oil-liquid separation.

In an optional solution, the return hole has a cutout 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 channels. The beneficial effect of this technical solution is: by designing the return hole as a cutout shape consistent with the flow direction of the gas and/or oil-gas mixture, it is more beneficial for the gas and/or oil-gas mixture to enter the return flow channel, so that more gas and/or The oil-air mixture can be separated twice to improve the separation effect.

In an optional solution, the disc has a hollow truncated circular structure, and an annular throttling rib is provided on the outer wall of the disc, and the throttling rib is a continuous or discontinuous structure. The beneficial effect of this technical solution is: the setting of the throttling rib has the function of promoting the oil-gas mixture to stay in the radial flow channel, so that the oil-gas mixture has enough time to be separated, and at the same time, the cross-section of the throttling rib is triangular, and the The plate acts like a springboard, guiding the oil-gas mixture to collide with the disc, and then the oil is separated, which can significantly improve the effect of oil-gas separation.

In an optional solution, in the direction from top to bottom of the main shaft, the throttling effect of the throttling ribs on the disc on the oil-air mixture gradually decreases. The beneficial effect of this technical solution is: by setting the throttling ribs, the throttling effect of the throttling ribs on the disc on the oil-gas mixture is gradually reduced from top to bottom, so that the flow rate of the radial flow channels of each layer tends to decrease. In the balance, and then significantly improve the utilization rate and separation efficiency of separation components.

In an optional solution, a plug is provided at the oil-gas inlet and/or the gas outlet, and the plug is used to separate part of the oil in the oil-gas mixture. The beneficial effect of this technical solution is: the connector 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 connector, and part of the oil will be in the Here, the large particle size oil is agglomerated on the connector and then separated, so as to play the role of pre-filtering the oil in the oil-gas mixture. Preferably, the connector located at the oil and gas inlet has an arc-shaped structure, which can guide the oil and gas mixture while separating part of the oil, so that the oil and gas mixture enters the separation assembly in a swirling manner, improving the subsequent oil and gas separation. Effect. The connector at the gas outlet is used to finally filter 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 connector here and reunite. After forming large particle size oil, it is separated to ensure the purity of exhaust gas and reduce oil loss. In addition, the connectors 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, and the pressure rise is high, which can ensure the connection with the centrifugal oil-gas separation device The negative pressure in the crankcase is large, the oil and gas are not easy to overflow, and the reliability is high.

Compared with the prior art, the beneficial effects of the present invention include at least: constructing the inner circulation channel by setting the sleeve, so that part of the gas and/or oil-gas mixture can be refluxed to achieve secondary separation, promote flow balance, and significantly strengthen oil-gas separation Effect.

Description of drawings

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

Fig. 2 is a top view of the centrifugal oil-gas separation device of the embodiment of the present invention.

Fig. 3 is a sectional view along line A-A of Fig. 2 .

Fig. 4 is a schematic structural diagram of a casing according to an embodiment of the present invention.

Fig. 5a is a first cross-sectional view along the line B-B in Fig. 4 without a separate component inside the housing.

Fig. 5b is a second cross-sectional view along line B-B in Fig. 4 without a separate component inside the casing.

Fig. 5c is a third cross-sectional view along line B-B in Fig. 4 without a separate component inside the casing.

Fig. 6 is a perspective view of a separation assembly of an embodiment of the present invention.

FIG. 7 is a schematic structural diagram of a disc according to an embodiment of the present invention.

Fig. 8 is a sectional view along line C-C of Fig. 4 .

Fig. 9 is a cross-sectional view along line D-D of Fig. 4 .

Fig. 10 is a schematic diagram of force analysis of a droplet on a disc.

Fig. 11 is a schematic diagram of oil and gas flow when the oil and gas inlet and gas outlet are respectively arranged on the upper and lower sides of the housing.

In the figure: 1. Shell; 11. Oil and gas inlet; 12. Air outlet; 2. Separation assembly; 21. Main shaft; 22. Lower pressure shell; 23. Disc; , Archimedes spiral flow channel; 32, impeller; 4, sleeve; 41, return hole; 5, internal circulation gap; 6, return flow channel; 7, throttle rib; 8, connector.

Detailed ways

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals denote the same or similar structures in the drawings, and thus their repeated descriptions will be omitted.

The words expressing position and direction described in the present invention are all described by taking the accompanying drawings as an example, but changes can also be made according to needs, and all changes are included in the protection scope of the present invention.

Referring to FIGS. 1-3 , the present invention provides a centrifugal oil-gas separation device, which includes a casing 1 , a separation assembly 2 , an inner circulation member 3 and a sleeve 4 .

An oil and gas inlet 11 and an oil return port (not shown) are arranged on the casing 1 near the bottom, and an air outlet 12 is arranged on the casing 1 near the top.

The separation assembly 2 includes a main shaft 21, a lower pressure shell 22 and a plurality of discs 23, at least a part of the main shaft 21 is rotatably arranged in the housing 1, and a plurality of discs 23 are stacked on the main shaft 21, and formed with a disc along the direction of the main shaft 21 The extended axial flow channel and the radial flow channel between two adjacent discs 23 (as shown in Figure 6), the lower pressure shell 22 is arranged on the main shaft 21 and is located below a plurality of discs 23, from The oil-gas mixture input from the oil-gas inlet 11 flows through the axial flow channel and the radial flow channel in turn, and the gas and oil are separated under the centrifugal action of the separation assembly 2, and the separated oil is discharged through the oil return port.

The inner circulation part 3 is arranged in the casing 1 and is located below the lower pressure shell 22 , and an inner circulation gap 5 is formed between the inner circulation part 3 and the lower pressure shell 22 .

The sleeve 4 is arranged on the inner wall of the housing 1, and a backflow channel 6 is formed in the sleeve 4 or between the sleeve 4 and the inner wall of the housing 1, and the inner peripheral wall of the sleeve 4 is provided with a wall connecting the backflow channel 6. A plurality of backflow holes 41, and there is a gap between the inner peripheral wall of the sleeve 4 and the edge of the separation assembly 2, the top of the backflow channel 6 is sealed, and the bottom of the backflow channel 6 has an opening toward the bottom of the housing 1, Part of the gas and/or oil-gas mixture discharged from the radial channel passes through the return hole 41 , the return channel 6 and the internal circulation gap 5 in sequence, and then flows to the axial channel again.

The above-mentioned structure adopts the method of adding a sleeve 4 to build an internal circulation flow channel, 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 effect of oil-liquid separation.

In the present invention, the rotational speed of the main shaft 21 can be 6500-7500 rpm, for example, 7000 rpm. Compared with the existing rotational speed up to 10,000 rpm, by reducing the rotational speed, the support for the main shaft 21 can be significantly reduced. The damage of the bearing can significantly improve the reliability of the centrifugal oil-gas separation device. The number of discs 23 in the separation assembly 2 can be 15-30, preferably 20-25. Compared with the existing 40-50 discs 23, the centrifugal oil-gas separation can be reduced by reducing the number of discs 23 The volume and cost of the device enable the centrifugal oil-gas separation device to be assembled on more types of engines, and the reduction in the number of discs 23 can reduce the weight of the separation assembly 2 and reduce the damage to the bearing.

And only reducing the rotating speed of the main shaft 21, reducing the number of discs 23 and increasing the size of the separation space between the discs 23 will lead to a decline in separation efficiency to varying degrees, and will also cause the air outlet 12 and the oil and gas inlet 11 of the centrifugal oil-gas separation device. The pressure rise between them decreases, which in turn leads to a decrease in the negative pressure in the crankcase, which easily leads to oil and gas overflow, and reduces reliability. Among them, the decrease in separation efficiency is mainly due to the phenomenon of flow imbalance.

Specifically, when the number of existing discs 23 is large and the separation space of the discs 23 is small, the airflow resistance between the discs 23 is large, and the oil-air mixture is more likely to pass through the separation between the discs 23 in the up and down direction evenly. The phenomenon of unbalanced space and flow is not obvious. And when the number of discs 23 is reduced and the separation space between discs 23 is increased, as shown in Figure 11, when the oil-air mixture flows from bottom to top through the axial channels of a plurality of stacked discs 23, the oil-air mixture Under the action of flow inertia, the oil-air mixture tends to flow out through the separation space between the multiple discs 23 near the top, resulting in a large flow of the oil-air mixture between the discs 23 near the top and the disc 23 near the bottom. The flow rate of the oil-air mixture between them is small, resulting in a prominent flow imbalance. The direct result of the flow imbalance is that small droplets (about 1 μm) of oil in the oil-air mixture near the upper disc 23 are on the disc 23 The residence time on the surface is shortened, resulting in the inability of the small droplets to reunite into large droplets, making it easier for the small droplets to be discharged out of the centrifugal oil-gas separation device with the gas, resulting in a decrease in the separation efficiency.

More specifically, with reference to FIG. 10, FIG. 10 is a schematic diagram of force analysis of a droplet on the disc 23. The droplet is subjected to drag force and inertial force towards the lower edge of the disc 23 on the disc 23 and towards the disc 23. The effect of the pressure gradient force on the upper edge of the disc 23, when the resultant force of the pressure gradient force, drag force and inertial force tends to be positive, the droplet tends to stay on the disc 23.

The drag force Fd is

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

It can be seen that the drag force is the thrust/resistance of the gas relative to the liquid droplet, and the direction depends on the velocity of the liquid drop below/higher than the gas phase. The drag force of the droplet on the disc 23 is outward, which is proportional to the projected area of the droplet. The smaller the radial velocity of the airflow, the smaller the drag force, which is more conducive to the retention of droplets; otherwise, the escape of droplets increases. When the flow is unbalanced, the flow velocity of the oil in the oil-air mixture between the discs 23 near the top increases, the drag force increases, the droplets accelerate to escape, and the separation efficiency decreases.

The inertial force F _MRF is F _MRF =m _p [ω×(ω×r)+2(ω×V _p )].

where mp is the droplet mass, ω is the angular velocity vector of the rotating reference frame, r is the distance vector to the axis of rotation, and Vp is the droplet volume.

Inertial force includes centrifugal force and Coriolis force (earth rotation deflection force). The inertial force of the droplet on the disc 23 is outward and leftward, and is proportional to the mass of the droplet. As the particle size decreases, the turbulent dissipation is enhanced and the influence of the inertial force is weakened.

The pressure gradient force Fp is

是气相中静压的梯度。where Vp is the volume of the droplet,

is the gradient of static pressure in the gas phase.

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

From the above analysis, it can be seen that how to improve the structure of the centrifugal oil-gas separation device for the centrifugal oil-gas separation device using the number of discs 23 and the separation space of the small discs 23 so that the flow rate of the oil-gas mixture between the discs 23 Tend to balance, and then increase the residence time of small droplets of about 1 μm on the disc 23, which is the key to improving the separation efficiency.

In the present invention, in order to reduce the rotational speed of the rotating shaft, reduce the number of discs 23 and increase the separation space of the discs 23, the centrifugal oil-gas separation device is kept in line with the existing high rotational speed of the rotating shaft, the number of multi-discs 23 and the number of small discs 23 The centrifugal oil-gas separation device in the separation space maintains considerable separation efficiency, and the present invention makes a series of improvements to the centrifugal oil-gas separation device.

Specifically, the inner circulation channel is constructed by adding the 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, The other part can enter the return channel 6 through the return hole 41, because in the process of high-speed rotation, the lower area of the separation assembly 2 will form a relatively low-pressure environment relative to its outer peripheral area, that is, the lower part of the separation assembly 2 and the inner circulation part 3 The formed area is relatively low-pressure environment relative to the bottom area of the return flow channel 6. Therefore, the gas and/or oil-gas mixture entering the return flow channel 6 will flow into the lower area of the separation assembly 2 again under the action of air pressure, through the axial flow. The channel enters the radial flow channel again and is separated again under the action of centrifugal force. On the one hand, a part of the oil-air mixture that is not completely separated can pass through the disc 23 for separation for many times, increasing the liquid drop on the disc 23. Residence time, on the other hand, by forming the internal circulation flow of the oil-air mixture, part of the oil-air mixture between the multiple discs 23 near the top can participate in the internal circulation again, which is beneficial to increase the oil-air mixture between the multiple discs 23 near the bottom The flow rate is high, and the flow balance is promoted, so that the centrifugal oil-gas separation device can still maintain a high separation efficiency under the premise of low speed, small number of discs 23 and large gap between discs 23 . In addition, the gas and/or oil-gas mixture entering the backflow channel 6 is less affected by the gas and/or oil-gas mixture thrown between the discs 23, and the gas and/or oil-gas mixture flows downward more easily, so the internal circulation The flow is smoother, which promotes flow balance more effectively.

Referring to FIG. 4 and FIG. 5 a , in a specific embodiment, a plurality of return holes 41 are only distributed on the inner peripheral wall of the upper half of the sleeve 4 .

From Fig. 3 and Fig. 6, the diameter of the axial flow channel of the separation assembly 2 is relatively large, and the gap of the radial flow channel is small. The flow rate of the flow channel also decreases from top to bottom, causing the oil-air mixture to concentrate on the upper half of the separation assembly 2, so that the separation effect of the upper half of the separation assembly 2 is correspondingly poor. The above-mentioned structure is provided with a return hole 41 on the inner peripheral wall of the upper part of the sleeve 4, and part of the gas and/or oil-gas mixture separated in the upper part can be introduced into the return flow channel 6, and the internal circulation flow channel constructed is used to realize Secondary separation enhances the effect of oil-liquid separation.

Referring to Fig. 4 and Fig. 5b, 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 distribution density on .

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. The above structure sets the density of the return holes 41 so that the return holes 41 near the top of the sleeve 4 The density is greater than the density of the return hole 41 near the bottom of the sleeve 4, which can control the flow of the gas and/or oil-gas mixture entering the return flow channel 6, and always keep the flow of the upper half of the separation assembly 2 greater than that of the lower half The flow rate is so that more of the gas and/or oil-gas mixture in the upper part can be separated for the second time, so as to ensure the effect of oil-liquid separation.

Preferably, in the direction from the top to the bottom of the sleeve 4, the distribution density of the return holes 41 decreases gradually. According to the separation effect of the radial flow channels of each layer, this design gradually reduces the flow rate of the gas and/or the oil-gas mixture introduced into the return flow channel 6 from top to bottom, so that the oil-gas mixture at different positions can be more accurately processed twice. Separation, to further strengthen the effect of oil-liquid separation.

Referring to Fig. 4 and Fig. 5c, in another preferred embodiment, a plurality of return holes 41 are evenly distributed on the inner peripheral wall of the sleeve 4, and the return holes on the inner peripheral wall near the top of the sleeve 4 The aperture of 41 is larger than the aperture of the return hole 41 on the inner peripheral wall near the bottom of the sleeve 4 .

Similar to controlling the distribution density of the return holes 41, the above-mentioned structure sets the apertures of the return holes 41 so that the apertures of the return holes 41 near the top of the sleeve 4 are larger than the apertures of the return holes 41 near the bottom of the sleeve 4. The flow of the gas and/or the oil-gas mixture entering the backflow channel 6 is controlled, and the flow of the upper half of the separation assembly 2 is kept greater than the flow of the lower half, so that the gas and/or the oil-gas mixture of the upper half can have more The amount is separated twice to ensure the effect of oil separation.

Preferably, in the direction from the top to the bottom of the sleeve 4, the diameter of the return hole 41 decreases gradually. This design can also gradually reduce the flow rate of the gas and/or oil-gas mixture introduced into the return channel 6 from top to bottom, so that the oil-gas mixture at different positions can be separated more accurately, and the effect of oil-liquid separation can be further enhanced.

In a specific embodiment, the return hole 41 has a notch shape on the inner peripheral wall of the sleeve 4 that is consistent with the flow direction of the gas and/or the oil-gas mixture discharged from most of the radial channels.

By designing the return hole 41 into a slit shape consistent with the flow direction of the gas and/or the oil-gas mixture, it is more beneficial for the gas and/or the oil-gas mixture to enter the return channel 6, so that more gas and/or the oil-gas mixture can be secondary Separation, thereby improving the separation effect.

In a specific embodiment, the inner peripheral wall of the sleeve 4 and/or the inner wall of the housing 1 is provided with an oleophobic layer.

After the oleophobic layer is set, it is not only beneficial for the separated small particles of oil to slide and gather to form large particles of oil, which can increase the return rate of the oil, but also prevent the oil from adhering to the inner wall to form sludge. In this embodiment, the oleophobic layer is preferably 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 poly One of perfluoroethylene propylene layer, tetrafluoroethylene copolymer layer, polyvinylidene fluoride layer, and soluble tetrafluoroethylene layer. The oleophobic layer of the above materials not only has a high oil return rate, but also does not react with oil, and has long-term durability. reliability.

Referring to Figures 6-7, in a specific embodiment, the disk 23 is a hollow circular truncated structure, and the outer wall of the disk 23 is provided with an annular throttling rib 7, which is continuous or discontinuous structure.

The above-mentioned structure has the effect of promoting the oil-gas mixture to stay in the radial flow channel by setting the throttle rib 7, so that the oil-gas mixture has enough time to be separated. Acting like a springboard, it guides the oil-air mixture to collide with the disc 23, and then the oil is separated, which can significantly improve the effect of oil-air separation.

In a preferred embodiment, in the direction of the main shaft 21 from top to bottom, the throttling effect of the throttling ribs 7 on the disc 23 on the oil-air mixture gradually decreases.

Referring to the above, the upper half of the separation assembly 2 actually participates in the oil-gas separation, and the lower half of the separation assembly 2 only needs a small amount or even does not participate in the oil-gas separation process. The throttling effect of the throttle rib 7 on the disc 23 on the oil-air mixture is gradually reduced, so that the flow of the radial flow channels of each layer tends to be balanced, and then the utilization rate and separation efficiency of the separation assembly 2 are significantly improved. Specifically, the following methods can be used (not shown):

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

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

In the direction from top to bottom of the main shaft 21, the diameter of the through hole on the throttle rib 7 of the disc 23 gradually increases; or,

The throttling rib 7 has a discontinuous structure, and in the direction from top to bottom of the main shaft 21 , the distance between the ribs of the throttling rib 7 of the disc 23 gradually increases; or,

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

The above several throttling ribs 7 schemes can gradually reduce the throttling effect of the separation assembly 2 from top to bottom, thereby ensuring that the flow of each radial flow channel tends to be balanced, and significantly improving the utilization rate and separation of the separation assembly 2. efficiency.

Still referring to Fig. 3 and Fig. 8, in a specific embodiment, the internal circulation member 3 includes a cyclone 31, which is arranged between the oil-gas inlet 11 and the separation assembly 2, and the cyclone 31 is used to carry out the oil-gas mixture Supercharging and strengthening the swirling effect.

After the cyclone 31 is installed in the above structure, the oil-gas mixture input into the cyclone 31 from the oil-gas inlet 11 will enter the separation assembly 2 in a swirling manner. During this process, the oil-gas mixture will collide with the cyclone 31 to separate part of the oil, and at the same time The cyclone 31 will pressurize the oil-air mixture and strengthen its swirling effect, so that the oil-air mixture can obtain better centrifugal separation effect after entering the separation assembly 2 . To better guide the oil-gas mixture into the cyclone 31, as shown in Figure 8, an Archimedes spiral flow channel 311 can also be set between the cyclone 31 and the oil-gas inlet 11, using the Archimedes spiral flow Road 311, not only has high separation efficiency, but also can accelerate the flow of airflow, and play a better supercharging effect. In the case of reducing the rotation speed of the main shaft 21, reducing the number of discs 23 and increasing the gap between the discs 23, the supercharging effect of the above structure can be Keep a relatively high pressure rise between the air outlet 12 and the oil-air inlet 11 of the centrifugal oil-gas separation device.

The inner circulation part 3 can also include an impeller 32, which is arranged on the main shaft 21, and the impeller 32 is located between the cyclone cylinder 31 and the separation assembly 2, and the impeller 32 is used for pressurizing the oil-gas mixture and enhancing the swirling effect.

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-air mixture to separate part of the oil, and at the same time pressurize and disturb the oil-air mixture to make the original swirl The oil-air mixture can enter the separation assembly 2 at a higher speed of swirl, thereby further improving the effect of centrifugal separation. In addition, the supercharging effect of the impeller 32 can also increase the pressure rise between the air outlet 12 and the oil-gas inlet 11, and the pressure rise is relatively high, which can ensure the negative pressure in the crankcase (not shown) connected to the centrifugal oil-gas separation device. High pressure, oil and gas are not easy to escape, high reliability.

Referring to Figure 4 and Figures 8-9, in a specific embodiment, a plug-in piece 8 is provided at the oil-gas inlet 11 and/or the gas outlet 12, and the plug-in piece 8 is used to separate part of the oil in the oil-gas mixture .

In the above structure, the connector 8 at the oil and gas inlet 11 is used to filter the oil in the oil and gas mixture. Specifically, when the oil and gas mixture enters from the oil and gas inlet 11, it will first collide with the connector 8, and part of the oil will be here. Agglomerated on the connector 8 at the position to form a large particle size oil and then separated, so as to play the role of pre-filtering the oil in the oil-gas mixture. Preferably, the connector 8 located at the oil and gas inlet 11 has an arc-shaped structure, which can also guide the oil and gas mixture while separating part of the oil, so that the oil and gas mixture enters the separation assembly 2 in a swirling manner, improving The effect of subsequent oil-gas separation. The connector 8 at the gas outlet 12 is used to finally filter the oil in the oil-gas mixture. Specifically, when the gas is discharged from the gas outlet 12, a small amount of oil remaining in the gas will collide with the connector 8 here , and is separated after agglomeration to form large particle size oil to ensure the purity of the exhaust gas and reduce oil loss.

In addition, the connector 8 at the oil-gas inlet 11 and the gas outlet 12 can also increase the flow rate of the oil-gas mixture, thereby increasing the pressure rise between the gas outlet 12 and the oil-gas inlet 11. The negative pressure in the crankcase connected with the type oil-gas separation device is large, and the oil and gas are not easy to overflow, and the reliability is high.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limitations to the present invention. Under the circumstances, the above embodiments can be changed, modified, replaced and modified within the scope of the invention, and all these changes should fall within the protection scope of the claims of the present invention.

Claims (10)

1. A centrifugal oil-gas separation device, comprising:

the shell is provided with an oil gas inlet and an oil return port close to the bottom, and an air outlet close to the top;

the separation assembly comprises a main shaft, a pressing shell and a plurality of discs, at least one part of the main shaft is rotatably arranged in the shell, the discs are stacked on the main shaft and are provided with an axial flow passage extending along the main shaft direction and a radial flow passage positioned between two adjacent discs, the pressing shell is arranged on the main shaft and positioned below the discs, an oil-gas mixture input from the oil-gas inlet sequentially flows through the axial flow passage and the radial flow passage, gas and oil are separated under the centrifugal action of the separation assembly, and the separated oil is discharged through the oil return port;

the internal circulation piece is arranged in the shell and positioned below the lower pressing shell, and an internal circulation gap is formed between the internal circulation piece and the lower pressing shell;

the sleeve is arranged on the inner wall of the shell, a backflow flow channel is formed in the sleeve or between the sleeve and the inner wall of the shell, a plurality of backflow holes communicated with the backflow flow channel are formed in the inner peripheral wall of the sleeve, a gap is reserved between the inner peripheral wall of the sleeve and the edge of the separation assembly, the top of the backflow flow channel is sealed, an opening facing the bottom of the shell is formed in the bottom of the backflow flow channel, and partial gas and/or oil-gas mixture discharged from the radial flow channel sequentially passes through the backflow holes, the backflow flow channel and the inner circulation gap and then flows to the axial flow channel again.

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

3. The centrifugal oil and gas separation device of claim 2, wherein the distribution density of the return holes gradually decreases in a direction from the top to the bottom of the sleeve.

4. The centrifugal oil and gas separation device of claim 1, wherein a plurality of said return holes are uniformly distributed on an inner peripheral wall of said sleeve, and wherein said return holes near a top of said sleeve have a larger pore size than said return holes near a bottom of said sleeve.

5. The centrifugal oil and gas separation device of claim 4, wherein the bore diameter of the return bore gradually decreases in a direction from the top to the bottom of the sleeve.

6. The centrifugal oil and gas separation device of claim 1, wherein a plurality of said return holes are distributed only on an inner peripheral wall of an upper half of said sleeve.

7. The centrifugal oil and gas separation device according to claim 1, wherein the return holes have a slit shape on an inner peripheral wall of the sleeve in conformity with a flow direction of gas and/or oil-gas mixture discharged from a plurality of radial flow passages.

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

9. The centrifugal oil-gas separation device according to claim 8, wherein the throttle rib on the disc gradually reduces the throttle effect on the oil-gas mixture in the direction from top to bottom of the main shaft.

10. The centrifugal oil-gas separation device according to claim 1, wherein a plug-in connector is arranged at the oil-gas inlet and/or the gas outlet, and is used for separating part of oil in the oil-gas mixture.

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