Centrifugal separator and stack thereof

Abstract

The present application provides a centrifugal separator and a stack thereof, wherein the stack comprises a plurality of stacked discs; each disc is a hollow truncated cone structure with interconnected openings at its upper and lower ends; an axial hole and a plurality of air passages distributed around the axial hole are provided in the opening at the upper end of each disc; when two adjacent discs are stacked, a separation space is formed that is connected to the air passage and is used for oil and gas separation; each disc is provided with at least one bypass hole on its side so that a gas-liquid mixture flows from the bottom of the stack to the top through the air passage into the separation space between the two adjacent discs, and part of the gas-liquid mixture flows downward to the next disc through the bypass hole of each disc. High oil and gas separation efficiency and effect can be maintained under the premise of low rotor speed, small number of discs, and large disc gap.

Description

Technical Field

[0001] The present application relates to the technical field of centrifugal separators, and in particular to centrifugal separators and stacked bodies thereof. Background Art

[0002] Centrifugal separators are widely used in the fields of shipping, automobiles, chemical industry, metallurgy, etc. Centrifugal separators can separate mixtures of fluids with different densities from each other. One specific use of this type of centrifugal separator is to separate oil from the gas discharged from the crankshaft housing of an internal combustion engine.

[0003] As an example, a centrifugal separator is installed in an existing engine system. The discharged oil and gas mix to form a gas-liquid mixture. The gas-liquid mixture enters the centrifugal separator, and the rotor drives the disc to rotate. The gas-liquid mixture flows outward through the gap between the two discs. The liquid and gas are separated by centrifugal force, and the separated liquid is sent back to the interior of the crankcase through the oil return port to participate in the lubrication of the crankcase, thereby avoiding or reducing the loss of oil during actual operation.

[0004] To improve separation efficiency, current centrifugal separators usually increase the rotor speed, increase the number of discs, and reduce the disc gap to improve oil-gas separation efficiency. The current rotor speed is as high as 10,000 revolutions per minute, and the number of discs is 40-50. The problem is that when the separator's rotor rotates at high speed, although the separation efficiency is high, it will inevitably cause damage to the bearings connected to the rotor to varying degrees, resulting in a decrease in bearing service life and, in turn, a decrease in separator reliability. Increasing the number of discs and reducing the disc gap, which is usually around 0.4mm, will not only increase the cost and volume of the centrifugal separator, but also make it impossible to install the centrifugal separator on some engines due to the large bearing load. More importantly, although reducing the disc gap can improve separation efficiency, practice has shown that a small disc gap is more likely to cause sludge to clog the disc gap, which in turn leads to a decrease in reliability.

[0005] Therefore, there is still a need for a centrifugal separator that can maintain high separation efficiency under the premise of low rotor speed, small number of discs and large disc gap. Summary of the Invention

[0006] The purpose of this application is to provide a centrifugal separator and its stack, which can maintain a high oil-gas separation efficiency and oil-gas separation effect under the premise of low rotor speed, small number of discs and large disc gap.

[0007] The purpose of this application is achieved by the following technical solutions:

[0008] In a first aspect, the present application provides a stack of centrifugal separators, the stack comprising a plurality of discs stacked;

[0009] Each disc is a hollow truncated cone with interconnected openings at its upper and lower ends. The opening at the upper end of each disc is provided with an axial hole and multiple air passages distributed around the axial hole. When two adjacent discs are stacked, a separation space is formed between them, which is connected to the air passage and is used for oil and gas separation.

[0010] At least one bypass hole is provided on the side of each disc so that the gas-liquid mixture flows from the bottom of the stack through the air passage to the top into the separation space between two adjacent discs, and part of the gas-liquid mixture flows downward to the next disc through the bypass hole of each disc.

[0011] The beneficial effect of this technical solution is that when the centrifugal separator adopts a lower speed, a smaller number of discs and a large disc gap, the oil and gas separation efficiency will decrease. This is because in the process of the gas-liquid mixture flowing along the bottom of the stack through the air channel to the top of the stack, due to the low speed and the large disc gap, the centrifugal force is reduced. In addition, the flow of the gas-liquid mixture is affected by the inertia of the gas, and more gas-liquid mixture will flow into the separation space corresponding to the upper disc, while only a small part of the gas-liquid mixture will flow into the separation space corresponding to the lower disc, which leads to flow imbalance. In other words, only the upper disc makes a greater contribution to the oil and gas separation, and the utilization rate of the lower disc is far lower than that of the upper disc, resulting in low oil and gas separation efficiency.

[0012] By setting bypass holes on the sides of the discs, when the gas-liquid mixture flows into the separation space between any two adjacent discs, the pressure difference between the inner and outer areas of the bypass holes will cause part of the gas-liquid mixture to flow to the lower disc through the bypass holes. In other words, part of the gas-liquid mixture originally on the upper disc will flow to the lower disc. This part of the gas-liquid mixture will pass through the lower disc or even the lower disc and be separated again, thereby improving the problem of flow imbalance. In addition, the gas-liquid mixture can be separated more times, and a high oil-gas separation efficiency and effect can be maintained under the premise of low rotor speed, small number of discs and large disc gap.

[0013] In some optional embodiments, along the stacking direction from top to bottom of the stack, the opening area of ​​the bypass hole of the disc gradually decreases.

[0014] The beneficial effect of this technical solution is that due to the influence of gas inertia, more gas-liquid mixture will converge on the upper disc. If the problem of flow imbalance is to be changed, the throttling requirement of the upper disc must be greater than that of the lower disc. In other words, the gas-liquid mixture on the upper disc is more filled, and a bypass hole with a larger orifice needs to be opened.

[0015] The orifice area of ​​the bypass hole of the disc near the top of the stack (the upper disc) is larger, while the orifice area of ​​the bypass hole of the disc near the bottom of the stack (the lower disc) is smaller, which improves the overall flow distribution imbalance of the stack, promotes flow balance, and further improves separation efficiency.

[0016] In some optional embodiments, the number of the bypass holes of each disc is at least two, and the bypass holes are distributed in a ring array around the central axis of the shaft hole.

[0017] The beneficial effect of this technical solution is that the bypass holes are distributed in a circular array around the central axis of the shaft hole. In this way, when the stack rotates around the axis, the force on each disc is relatively uniform, which is beneficial to extending the overall service life of the stack (if the bypass holes on the disc are unevenly distributed, it will cause uneven force on the disc, and in severe cases, it will cause increased wear between the shaft hole of the disc and the rotating shaft).

[0018] In some optional embodiments, the center of the bypass hole of the uppermost disc is adjacent to the upper edge of the side surface of the uppermost disc;

[0019] Along the stacking direction from the top to the bottom of the stack, the center of the bypass hole of the disc gradually moves away from the upper edge of the side surface of the disc.

[0020] The beneficial effect of this technical solution is that when the gas-liquid mixture flows into the separation space between any two adjacent discs, it gradually flows from the upper edge of the side of the disc to the lower edge. Because the throttling demand of the upper disc is greater than that of the lower disc, the closer the disc is to the top, the closer the center of the bypass hole is to the upper edge of the side of the disc. In this way, when the gas-liquid mixture just enters the separation space (the pressure difference on both sides of the bypass hole is large), more of it can flow to the next layer of disc (if the center of the bypass hole is far away from the upper edge of the side, the pressure difference on both sides of the bypass hole is small, the gas-liquid mixture flowing to the next layer of disc will become less, and the throttling effect will be weakened), further promoting flow balance and improving oil and gas separation efficiency.

[0021] In some optional embodiments, the number of bypass holes in each disc is the same;

[0022] The projections of the corresponding bypass holes of two adjacent discs in the stacking direction from the top to the bottom of the stack at least partially overlap.

[0023] The beneficial effect of this technical solution is that the projections of the bypass holes of adjacent discs at least partially overlap, which can further increase the pressure difference on both sides of the bypass holes of the discs, making it easier for the gas-liquid mixture to flow to the next disc.

[0024] In some optional embodiments, the outer side wall of each disc is provided with a plurality of throttling ribs, and the throttling ribs are used to throttle and increase the time that the liquid in the gas-liquid mixture stays on the outer side wall of the disc.

[0025] The beneficial effects of this technical solution are: by arranging multiple throttling ribs on the outer side wall of the disc, on the one hand, the tendency of the gas-liquid mixture to flow from the upper edge to the lower edge of the disc side can be slowed down, allowing more gas-liquid mixture to flow to the next layer of disc through the bypass hole, thereby playing a throttling role; on the other hand, it can cause the liquid in the gas-liquid mixture to stay on the outer side wall of the disc for a longer time, so that the small-particle liquid in the gas-liquid mixture has more opportunities to agglomerate into large-particle liquid, thereby improving the oil and gas separation effect.

[0026] In some optional embodiments, for each disc, the ratio of the length of each throttle rib to the gap between two adjacent throttle ribs is (5-10):1.

[0027] The beneficial effect of this technical solution is that there is a certain gap between two adjacent throttling ribs, which allows the gas-liquid mixture attached to the throttling ribs to flow out along the gap, avoiding blockage of the gas-liquid mixture. The gap width between the throttling ribs can be set according to actual needs. When the ratio of the length of the throttling rib to the gap between two adjacent throttling ribs is (5-10):1, it can prevent excessive accumulation of liquid in the gas-liquid mixture to cause blockage, and greatly increase the residence time of the liquid in the gas-liquid mixture on the outer wall of the disc, resulting in a better oil and gas separation effect.

[0028] In some optional embodiments, along the stacking direction from top to bottom of the stack, the throttling effect of the throttling ribs on the gas-liquid mixture gradually decreases;

[0029] The ratio of the height of the throttling ribs on the outer side wall of each disc to the overall height of the disc is 1:2.

[0030] The beneficial effects of this technical solution are: on the one hand, the throttling demand of the upper disc is greater than that of the lower disc, and the shape of the throttling rib (protruding thickness, shape, etc.) can be set so that the throttling effect of the throttling rib on the gas-liquid mixture gradually decreases from the top to the bottom of the stack (the throttling effect of the throttling rib of the disc near the top is large, and the throttling effect of the throttling rib of the disc near the bottom is small), further promoting flow balance and improving oil and gas separation efficiency; on the other hand, the height of the throttling rib on the outer wall can be half the overall height of the entire disc (moderate position), so that the throttling effect of the throttling rib and the effect of promoting liquid retention can be exerted to a greater extent.

[0031] In a second aspect, the present application provides a centrifugal separator, characterized in that it comprises any one of the stacking bodies described above.

[0032] In some optional embodiments, the centrifugal separator further comprises a housing and a rotating shaft;

[0033] The shell includes an air inlet, an air outlet and a liquid drain hole, the air outlet is close to the upper end of the shell, and the air inlet and the liquid drain hole are close to the lower end of the shell;

[0034] The rotating shaft passes through the axial hole of each disc of the stacked body, thereby driving the disc to rotate so that the gas-liquid mixture entering from the air inlet is separated into gas and liquid under the centrifugal separation action of the disc, and the separated gas is discharged outward through the air outlet, and the separated liquid is discharged outward through the drainage hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present application is further described below with reference to the accompanying drawings and examples.

[0036] Figure 1 This is a schematic structural diagram of a stacked body provided in an embodiment of the present application.

[0037] Figure 2 This is a structural diagram of a disc provided in an embodiment of the present application.

[0038] Figure 3 Schematic diagram of force analysis of a liquid droplet on a disc provided in an embodiment of the present application.

[0039] Figure 4 This is a partially exploded schematic diagram of another stacked body provided in an embodiment of the present application.

[0040] Figure 5 yes Figure 4 Cross-sectional view at AA in the middle.

[0041] Figure 6 It is a structural schematic diagram of a centrifugal separator provided in an embodiment of the present application.

[0042] Figure 7 yes Figure 6 Cross-sectional view at the middle BB.

[0043] In the figure: 10, stacked body; 11, disc; 111, shaft hole; 112, air passage; 113, bypass hole; 114, throttle rib; 20, housing; 21, air inlet; 22, air outlet; 23, rotating shaft. DETAILED DESCRIPTION

[0044] Below, the present application is further described in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0045] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c, a and b and c, where a, b and c can be single or multiple. It is worth noting that "at least one" can also be interpreted as "one or more items".

[0046] The words expressing position and direction described in the embodiments of the present application are all explained using the accompanying drawings as examples, but changes can be made as needed, and all changes are included in the scope of protection of the embodiments of the present application.

[0047] It should also be noted that in the examples of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any implementation or design described as "exemplary" or "for example" in the examples of this application should not be interpreted as being preferred or advantageous over other implementations or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0048] See also Figure 1 and Figure 2 , Figure 1 1 is a schematic structural diagram of a stacked body 10 of a centrifugal separator provided in an embodiment of the present application. Figure 2 1 is a structural diagram of a disc 11 provided in an embodiment of the present application.

[0049] The stack 10 includes a plurality of stacked discs 11 and may further include an upper pressure shell and a lower pressure shell (not shown). The upper pressure shell is located above the plurality of discs 11 and the lower pressure shell is located below the plurality of discs 11 .

[0050] Each disc 11 has a hollow frustum-shaped structure and is provided with openings that are interconnected at the upper and lower ends. An axial hole 111 and a plurality of air passages 112 distributed around the axial hole 111 are provided in the opening at the upper end of each disc 11. When two adjacent discs 11 are stacked, a separation space is formed that is connected to the air passage 112 and is used for oil and gas separation.

[0051] At least one bypass hole 113 is provided on the side of each disc 11, and the bypass hole 113 runs through the side of the disc 11 so that the gas-liquid mixture flows from the bottom of the stack 10 to the top through the air passage 112 and flows into the separation space between two adjacent discs 11, and part of the gas-liquid mixture flows downward to the next disc 11 through the bypass hole 113 of each disc 11.

[0052] When the centrifugal separator adopts a lower speed (for example, 6500-7500 rpm, typically 7000 rpm), a smaller number of discs 11 (for example, 15-30 discs, typically 20-25 discs) and a large gap between the discs 11 (for example, 0.7-0.9 mm, typically 0.8-0.9 mm), the oil-gas separation efficiency will be reduced. This is because when the gas-liquid mixture flows along the bottom of the stack 10 through the air passage 112 to the top of the stack 10, the centrifugal force is reduced due to the low speed and the large gap between the discs 11. In addition, the flow of the gas-liquid mixture is affected by the inertia of the gas, and more gas-liquid mixture will flow into the separation space corresponding to the upper disc 11, while only a small part of the gas-liquid mixture will flow into the separation space corresponding to the lower disc 11. This leads to flow imbalance. That is, only the upper disc 11 makes a greater contribution to oil-gas separation, and the utilization rate of the lower disc 11 is far lower than that of the upper disc 11, resulting in low oil-gas separation efficiency. In addition, more gas-liquid mixture flows into the separation space corresponding to the upper disc 11. The high air flow velocity also causes the small droplets to stay on the disc 11 for a short time and cannot agglomerate into large droplets, which also leads to low oil-gas separation efficiency.

[0053] By providing a bypass hole 113 on the side of the disc 11, when the gas-liquid mixture flows into the separation space between any two adjacent discs 11, a pressure difference is formed between the inner and outer areas of the bypass hole 113, which will cause part of the gas-liquid mixture to flow to the lower disc 11 through the bypass hole 113. In other words, part of the gas-liquid mixture originally located on the upper disc 11 flows to the lower disc 11. This part of the gas-liquid mixture will pass through the lower disc 11 or even the lower disc 11 to be separated again, thereby improving the problem of flow imbalance. In addition, the gas-liquid mixture can be separated more times, and a high oil-gas separation efficiency and effect can be maintained under the premise of low rotor speed, a small number of discs 11, and a large gap between the discs 11. In addition, the gas-liquid mixture flowing from the bypass hole 113 to the lower disc 11 will also produce a turbulent effect on the gas-liquid mixture flowing normally along the separation space between the lower discs 11, causing the gas-liquid mixture flowing normally along the separation space to change its flow path, causing more gas-liquid mixture to swirl, increasing the probability of collision with the surface of the disc 11, and thereby improving the separation effect.

[0054] The embodiment of the present application does not limit the shape of the bypass hole 113. The shape of the bypass hole 113 can be a regular shape such as a circle, an ellipse, a rectangle, a triangle, a regular polygon, or an irregular shape.

[0055] The embodiment of the present application does not limit the number of discs 11 in the stack 10. The number of discs 11 can be 15, 20 or 30. The gap between adjacent discs 11 formed after stacking can be 0.7 mm, 0.8 mm or 0.9 mm. Figure 3 , Figure 3 FIG. 1 is a schematic diagram of force analysis of liquid (hereinafter referred to as liquid droplet) on the outer wall of the disc 11 .

[0056] The droplets on the disc 11 are acted upon by the inertial force, the drag force toward the lower edge of the outer wall of the disc 11, and the pressure gradient force toward the upper edge of the outer wall of the disc 11. When the resultant force of the pressure gradient force, the drag force, and the inertial force tends to be positive, the droplets tend to stay on the disc 11.

[0057] Drag force F d The calculation formula is:

[0058] Among them, C d is the drag coefficient (or resistance coefficient) of the droplet, ρ is the density of the gas phase, v s is the relative slip velocity between the droplet and the gas phase, v s =vv p , v is the instantaneous velocity of the gas phase, v p is the instantaneous velocity of the droplet, A p is the projected area of ​​the liquid droplet on the outer wall of the disc 11.

[0059] As can be seen, drag, or the thrust / resistance exerted by the gas phase on the droplet, is directed outwards by the droplet's velocity relative to the gas phase's velocity. The drag on the droplet on disk 11 is proportional to its projected area and is directed outwards. The lower the radial velocity of the airflow, the smaller the drag, which promotes droplet retention; conversely, droplet escape increases. When flow is unbalanced, the liquid velocity in the gas-liquid mixture near the upper disk 11 increases, increasing drag and accelerating droplet escape, leading to reduced separation efficiency.

[0060] Inertial force F MRF The calculation formula is: F MRF =m p [ω×(ω×r)+2(ω×V p )].

[0061] Among them, m p is the mass of the droplet, ω is the angular velocity vector of the rotating reference coordinate system, r is the distance vector to the axis of rotation, V p is the volume of the droplet (droplet velocity v pThe v in the middle is a lowercase letter, which means the volume of the droplet is V. p V is a capital letter).

[0062] Inertial forces include centrifugal force and Coriolis force (Coriolis force). The inertial force of the droplets on the disc 11 is outward and leftward, which is proportional to the mass of the droplets. As the particle size decreases, turbulent dissipation increases and the influence of the inertial force decreases.

[0063] Pressure gradient force F p The calculation formula is:

[0064] Among them, V p is the volume of the droplet, is the gradient of static pressure in the gas phase.

[0065] The pressure gradient force can be understood as a generalized buoyancy force. The pressure gradient force on the droplets on disc 11 is directed inward and is proportional to the droplet volume. Large pressure gradients are likely to occur around the periphery of disc 11, and their magnitude depends on the rotational speed and flow-guiding structure. As the pressure gradient force increases and the drag force decreases to a critical point, the droplets become suspended, forming a concentrated zone, where their residence time increases and the agglomeration effect is enhanced.

[0066] From the above analysis, it can be seen that for centrifugal separators using a large number of discs 11 and small gaps between the discs 11, how to improve the structure of the centrifugal separator so that the flow rate of the gas-liquid mixture between the discs 11 tends to be balanced, thereby increasing the residence time of small droplets of about 1 μm on the discs 11, is the key to improving separation efficiency.

[0067] See also Figure 4 and Figure 5 , Figure 4 is a structural diagram of another stack 10 provided in an embodiment of the present application. Figure 5 yes Figure 4 Cross-sectional view at AA in the middle. Figure 5 The flow path of the gas-liquid mixture is indicated by arrows.

[0068] In some optional embodiments, along the stacking direction from top to bottom of the stack 10 , the opening area of ​​the bypass hole 113 of the disc 11 gradually decreases.

[0069] Due to the inertia of the gas, more of the gas-liquid mixture will converge on the upper disc 11. To correct the flow imbalance problem, the throttling requirement of the upper disc 11 must be greater than that of the lower disc 11. In other words, the gas-liquid mixture in the upper disc 11 is more filled, and a bypass hole 113 with a larger orifice needs to be opened.

[0070] The orifice area of ​​the bypass hole 113 of the disc 11 near the top of the stack 10 (the upper disc 11) is larger, while the orifice area of ​​the bypass hole 113 of the disc 11 near the bottom of the stack 10 (the lower disc 11) is smaller, which improves the overall flow distribution imbalance of the stack 10, promotes flow balance, and further improves separation efficiency.

[0071] In some optional embodiments, the number of the bypass holes 113 of each disc 11 is at least two, and the bypass holes 113 are distributed in a ring array around the central axis of the shaft hole 111 .

[0072] The bypass holes 113 are distributed in a circular array around the central axis of the shaft hole 111. In this way, when the stack 10 rotates around the axis, the force on each disc 11 is relatively uniform, which is beneficial to extending the overall service life of the stack 10 (if the bypass holes 113 on the disc 11 are unevenly distributed, it will cause uneven force on the disc 11. In severe cases, it will cause increased wear between the shaft hole 111 of the disc 11 and the rotating shaft 23).

[0073] In some optional embodiments, the center of the bypass hole 113 of the uppermost disc 11 is adjacent to the upper edge of the side surface of the uppermost disc 11 .

[0074] Along the stacking direction from top to bottom of the stack 10 , the center of the bypass hole 113 of the disc 11 gradually moves away from the upper edge of the side surface of the disc 11 .

[0075] When the gas-liquid mixture flows into the separation space between any two adjacent discs 11, it gradually flows from the upper edge of the side of the disc 11 to the lower edge. Because the throttling demand of the upper disc 11 is greater than that of the lower disc 11, the closer the disc 11 is to the top, the closer the center of the bypass hole 113 is to the upper edge of the side of the disc 11. In this way, when the gas-liquid mixture just enters the separation space (the pressure difference on both sides of the bypass hole 113 is large), more of it can flow to the next layer of disc 11 (if the center of the bypass hole 113 is far away from the upper edge of the side, the pressure difference on both sides of the bypass hole 113 is small, the gas-liquid mixture flowing to the next layer of disc 11 will become less, and the throttling effect will be weakened), further promoting flow balance and improving oil and gas separation efficiency.

[0076] In some optional embodiments, each disc 11 has the same number of bypass holes 113 , and the projections of the corresponding bypass holes 113 of two adjacent discs 11 in the stacking direction from top to bottom of the stack 10 at least partially overlap.

[0077] The projections of the bypass holes 113 of adjacent discs 11 at least partially overlap, which can further increase the pressure difference on both sides of the bypass holes 113 of the discs 11, making it easier for the gas-liquid mixture to flow to the next layer of discs 11, and also making it easier for the gas-liquid mixture between the upper discs 11 to flow to the bottom layer of discs 11.

[0078] In some optional embodiments, the outer wall of each disc 11 is provided with a plurality of throttling ribs 114 , and the throttling ribs 114 are used to throttle and increase the time that the liquid in the gas-liquid mixture stays on the outer wall of the disc 11 .

[0079] By providing a plurality of throttling ribs 114 on the outer wall of the disc 11, on the one hand, the tendency of the gas-liquid mixture to flow from the upper edge to the lower edge of the side of the disc 11 can be slowed down, allowing more gas-liquid mixture to flow to the next layer of disc 11 through the bypass hole 113, thereby playing a throttling role; on the other hand, it can cause the liquid in the gas-liquid mixture to stay on the outer wall of the disc 11 for a longer time, so that the small-particle liquid in the gas-liquid mixture has a better chance of agglomerating into large-particle liquid, thereby improving the oil-gas separation effect; in addition, the throttling ribs 114 can also change the flow path of the gas-liquid mixture that normally flows along the separation space, increase the probability of the gas-liquid mixture colliding with the surface of the disc 11, and thereby improve the separation effect.

[0080] In some optional embodiments, for each disc 11 , the ratio of the length of each throttle rib 114 to the gap between two adjacent throttle ribs 114 is (5-10):1.

[0081] There is a certain gap between two adjacent throttling ribs 114, which can allow the gas-liquid mixture or oil sludge attached to the throttling ribs 114 to flow out along the gap, avoiding clogging of the gas-liquid mixture or oil sludge. The gap width between the throttling ribs 114 can be set according to actual needs. When the ratio of the length of the throttling rib 114 to the gap between two adjacent throttling ribs 114 is (5-10):1, it can prevent the liquid or oil sludge in the gas-liquid mixture from excessively gathering and causing clogging, and greatly increase the residence time of the liquid in the gas-liquid mixture on the outer wall of the disc 11, so that the oil-gas separation effect is better, and a better balance is achieved between the two.

[0082] In some optional embodiments, along the stacking direction from top to bottom of the stack 10 , the throttling effect of the throttling ribs 114 on the gas-liquid mixture gradually decreases.

[0083] The ratio of the height of the throttling rib 114 on the outer side wall of each disc 11 to the overall height of the disc 11 is 1:2.

[0084] On the one hand, the throttling requirement of the upper disc 11 is greater than that of the lower disc 11. The shape of the throttling rib 114 (protruding thickness, shape, etc.) can be set so that the throttling effect of the throttling rib 114 on the gas-liquid mixture gradually decreases from the top to the bottom of the stack 10 (the throttling effect of the throttling rib 114 of the disc 11 near the top is large, and the throttling effect of the throttling rib 114 of the disc 11 near the bottom is small), further promoting flow balance and improving oil and gas separation efficiency; on the other hand, the height of the throttling rib 114 on the outer wall can be half the overall height of the entire disc 11 (moderate position), so that the throttling effect of the throttling rib 114 and the effect of promoting liquid retention can be exerted to a greater extent.

[0085] In some embodiments, the protruding portion of the throttling rib 114 can be a structure with sharp corners, and the cross-sectional shape of the protruding portion can be a triangle. In this way, the gas-liquid mixture can be further prevented from being blocked on the throttling rib 114, and the gas-liquid mixture flowing through can be ejected, thereby increasing the probability of collision between the gas-liquid mixture and the disc 11 and achieving a better separation effect.

[0086] In some embodiments, the throttling ribs 114 can be arranged horizontally, and the projection of the multiple throttling ribs 114 on each disc 11 from a top view of the disc 11 forms an open ring (the open ring is because there are gaps between the throttling ribs 114). In other words, the normal direction of the extension direction of the throttling ribs 114 is nearly perpendicular to the flow direction of the gas-liquid mixture from the upper edge to the lower edge of the disc 11. This can significantly slow the flow of the gas-liquid mixture from the upper edge to the lower edge of the disc 11, thereby achieving the effect of throttling and promoting liquid retention.

[0087] In some embodiments, along the stacking direction from top to bottom of the stack 10, the specific structural arrangement of the throttling ribs 114 on the outer side wall of the disc 11 includes the following methods:

[0088] Method 1: The gap between two adjacent throttling ribs 114 gradually increases from top to bottom of the stack 10. For example, in the first layer of discs 11 at the top, the gap between two adjacent throttling ribs 114 is 5 mm. With each layer of discs 11 going down, the gap between two adjacent throttling ribs 114 increases by 0.1 mm.

[0089] Method 2: The thickness of the protruding portion of the throttling rib 114 gradually decreases from the top to the bottom of the stack 10. For example, the thickness of the protruding portion of the throttling rib 114 in the first layer of discs 11 at the top is 4 mm. The thickness of the protruding portion of the throttling rib 114 decreases by 0.2 mm with each subsequent layer of discs 11.

[0090] Method 3: The number of throttling ribs 114 gradually decreases along the stacking direction from top to bottom of the stack 10. For example, the number of throttling ribs 114 in the first layer of discs 11 at the top is 16. The number of throttling ribs 114 decreases by one for every two layers of discs 11.

[0091] Method 4: Along the stacking direction from top to bottom of the stack 10, the discs 11 near the top are provided with throttling ribs 114, while the discs 11 near the bottom are not provided with throttling ribs 114. For example, there are 30 discs 11 in total. From the top down, 15 discs 11 are provided with throttling ribs 114, and the remaining discs 11 are not provided with throttling ribs 114.

[0092] See also Figure 6 and Figure 7 , Figure 6 is a structural schematic diagram of a centrifugal separator provided in an embodiment of the present application, Figure 7 yes Figure 6 Cross-sectional view at the middle BB.

[0093] The centrifugal separator includes any one of the stacking bodies 10 described above.

[0094] The centrifugal separator further includes a housing 20 and a rotating shaft 23 .

[0095] The housing 20 includes an air inlet 21, an air outlet 22 and at least one drain hole (not shown). The air outlet 22 is close to the upper end of the housing 20, and the air inlet 21 and the drain hole are close to the lower end of the housing 20. The drain hole can discharge the separated liquid into the crankcase.

[0096] The rotating shaft 23 passes through the axial hole 111 of each disc 11 of the stack 10, thereby driving the disc 11 to rotate so that the gas-liquid mixture entering from the air inlet 21 is separated into gas and liquid under the centrifugal separation action of the disc 11, and the separated gas is discharged outward through the air outlet 22, and the separated liquid is discharged outward through the drainage hole.

[0097] With all other parameters remaining the same, the rotational speed of the disc 11 was changed to compare the data of the centrifugal separator in the prior art (the stack 10 was not provided with the bypass hole 113) with the separator in this embodiment. As shown in Table 1, the separation efficiency was reflected in the laboratory by collecting the return oil volume.

[0098] Table 1

[0099] Speed / rpm 5000 6000 7000 8000 9000 Separation efficiency of existing technology 83.6％ 92.0％ 94.5％ 98.0％ 99.1％ The separation efficiency of this embodiment 86.9％ 93.9％ 96.7％ 98.9％ 99.4％

[0100] Through the comparison of the above data, it can be found that compared with the centrifugal separator without the bypass hole 113, the centrifugal separator of this embodiment has better separation efficiency, especially under the rotation speed condition of 5000-7000rpm, the centrifugal separator of this embodiment has better separation efficiency, and when using the centrifugal separator of this embodiment, the higher the rotation speed, the better the separation effect.

[0101] This application is explained from the perspectives of purpose of use, effectiveness, progress and novelty. The practical progress it has is in line with the functional enhancement and use requirements emphasized by the Patent Law. The above description and drawings of this application are only preferred embodiments of this application and are not intended to limit this application. Therefore, all structures, devices, features, etc. that are similar or identical to those of this application, that is, all equivalent replacements or modifications made in accordance with the scope of the patent application of this application, should fall within the scope of protection of the patent application of this application.

Claims

1. A stack of centrifugal separators, characterized in that: The stack includes a plurality of discs arranged in a stack; Each disc is a hollow truncated cone with interconnected openings at its upper and lower ends. The opening at the upper end of each disc is provided with an axial hole and multiple air passages distributed around the axial hole. When two adjacent discs are stacked, a separation space is formed between them, which is connected to the air passage and is used for oil and gas separation. At least one bypass hole is provided on the side of each disc, so that the gas-liquid mixture flows from the bottom of the stack through the gas passage to the top and flows into the separation space between two adjacent discs, and part of the gas-liquid mixture flows downward to the next disc through the bypass hole of each disc; Along the stacking direction from top to bottom of the stack, the opening area of ​​the bypass hole of the disc gradually decreases; The center of the bypass hole of the uppermost disc is adjacent to the upper edge of the side surface of the uppermost disc; Along the stacking direction from top to bottom of the stack, the center of the bypass hole of the disc gradually moves away from the upper edge of the side of the disc; Each disc has the same number of bypass holes; The projections of the corresponding bypass holes of two adjacent discs in the stacking direction from the top to the bottom of the stack at least partially overlap.

2. The stack of centrifugal separators according to claim 1, wherein: The number of the bypass holes of each disc is at least two, and the bypass holes are distributed in a ring array around the central axis of the shaft hole.

3. The stack of centrifugal separators according to claim 1, wherein: The outer side wall of each disc is provided with a plurality of throttling ribs, and the throttling ribs are used for throttling and increasing the time that the liquid in the gas-liquid mixture stays on the outer side wall of the disc.

4. The stack of centrifugal separators according to claim 3, characterized in that: For each disc, the ratio of the length of each throttle rib to the gap between two adjacent throttle ribs is (5~10):

1.

5. The stack of centrifugal separators according to claim 3, characterized in that: Along the stacking direction from the top to the bottom of the stack, the throttling effect of the throttling ribs on the gas-liquid mixture gradually decreases; Along the stacking direction from top to bottom of the stack, the gap between two adjacent throttling ribs gradually increases; or, along the stacking direction from top to bottom of the stack, the thickness of the protruding portion of the throttling rib gradually decreases; or, along the stacking direction from top to bottom of the stack, the number of throttling ribs gradually decreases; or, along the stacking direction from top to bottom of the stack, the disc adjacent to the top is provided with a throttling rib, while the disc adjacent to the bottom is not provided with a throttling rib; The ratio of the height of the throttling ribs on the outer side wall of each disc to the overall height of the disc is 1:

2.

6. A centrifugal separator, characterized in that: The stacked body comprises the stacked body according to any one of claims 1 to 5.

7. The centrifugal separator according to claim 6, characterized in that The centrifugal separator also includes a shell and a rotating shaft; The shell includes an air inlet, an air outlet and a liquid drain hole, the air outlet is close to the upper end of the shell, and the air inlet and the liquid drain hole are close to the lower end of the shell; The rotating shaft passes through the axial hole of each disc of the stacked body, thereby driving the disc to rotate so that the gas-liquid mixture entering from the air inlet is separated into gas and liquid under the centrifugal separation action of the disc, and the separated gas is discharged outward through the air outlet, and the separated liquid is discharged outward through the drainage hole.

Images