Centrifugal separator for cleaning gas
By introducing radial disk elements and guide vane design within the stationary housing, the problems of insufficient rigidity and poor oil discharge in crankcase centrifugal separators are solved, achieving efficient separation of liquid impurities and stable oil discharge, making it suitable for high-temperature and vibration environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AFDEX CO LTD
- Filing Date
- 2022-03-22
- Publication Date
- 2026-05-26
AI Technical Summary
Existing crankcase centrifugal separators using plastic components suffer from insufficient rigidity and poor oil drainage, especially under high temperature and vibration conditions, making it difficult to effectively separate and discharge liquid impurities.
The design employs radial disk elements and guide vanes within a static housing. The radial disk elements increase rigidity, while the guide vanes guide separated liquid impurities from a radially external position to the discharge outlet, forming a sandwich structure to stabilize oil discharge.
The rigidity and oil discharge efficiency of the centrifugal separator have been improved, the circulation airflow has been prevented from affecting oil discharge, and a compact separator structure has been achieved, making it suitable for high temperature and vibration environments.
Smart Images
Figure CN117177820B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of centrifugal separators for cleaning gases containing liquid contaminants. In particular, this invention relates to separators for cleaning crankcase gases of combustion engines to remove oil particles. Background Technology
[0002] It is well known that mixtures of fluids with different densities can be separated from each other by using a centrifugal separator. One specific application of such a separator is to separate oil from the gases discharged from the crankcase (which forms part of an internal combustion engine).
[0003] Regarding this specific application of the separator, there is a tendency for high-pressure gases found in the combustion chamber of an internal combustion engine to leak through the associated piston rings and into the engine crankcase. This continuous leakage of gas into the crankcase can cause an undesirable increase in pressure within the crankcase, thus necessitating the venting of gas from the casing. Such gas vented from the crankcase typically carries a certain amount of engine oil (as drops or a fine mist), which is obtained from an oil reservoir contained within the crankcase.
[0004] To allow exhaust gases to be introduced into the inlet system without introducing unwanted oil (especially in turbocharged systems where compressor efficiency can be adversely affected by the presence of oil), it is necessary to clean the exhaust gases (i.e., remove oil carried by the gases) before they are introduced into the inlet system. This cleaning process can be performed by a centrifugal separator mounted on or near the crankcase, which directs the cleaned gases into the inlet system and directs the separated oil back into the crankcase. An example of such a separator is disclosed, for instance, in US 8,657,908.
[0005] In crankcase centrifugal separators, using plastic components (rather than steel or aluminum, for example) can be advantageous to reduce the cost and weight of the separator. However, such designs also need to bear the loads of the rotating parts, which are subsequently affected by engine vibrations. Furthermore, the heat from the warm engine oil that can propel the turbine (and therefore the rotating parts of the separator) can also affect the rigidity of the plastic components of the separator. Additionally, in crankcase centrifugal separators, the separated liquid impurities (such as oil) may be difficult to drain from the separation space due to the circulating airflow caused by the rotor.
[0006] Therefore, there is a need in the art for a centrifugal separator for cleaning crankcase gases that includes a plastic part but still has good properties in terms of rigidity and stability, which in turn provides for satisfactory oil discharge from the separation space. Summary of the Invention
[0007] The objective of this invention is to overcome, at least in part, one or more limitations of the prior art. In particular, the objective is to provide a centrifugal separator with increased rigidity and improved oil discharge from the separation space.
[0008] As a first aspect of the invention, a centrifugal separator for cleaning gases containing contaminants is provided, the centrifugal separator comprising:
[0009] A stationary shell surrounds the separation space, allowing airflow through it. The stationary shell includes surrounding sidewalls, an upper end wall, and a lower end wall.
[0010] A gas inlet extends through the stationary housing and allows for the supply of gas to be cleaned.
[0011] A rotating component comprising a plurality of separating components arranged in the separating space and configured to rotate about a rotation axis (X);
[0012] A gas outlet, disposed within the stationary shell and configured to allow the discharge of clean gas, includes an outlet opening through the wall of the stationary shell.
[0013] An exhaust outlet is located in the lower portion of the stationary shell and configured to allow the discharge of liquid contaminants separated from the gas to be cleaned.
[0014] A drive component for rotating the rotating component;
[0015] The centrifugal separator also includes at least one guide vane, which is arranged to guide separated liquid impurities on the inner surface of the lower end wall from a radially external position to the discharge outlet.
[0016] The centrifugal separator further includes a radial disk element disposed on the top of at least one guide vane, wherein the radial disk element extends radially in the separation space to a position radially inward from the surrounding sidewall, thereby forming an annular channel for separating liquid impurities at the inner surface of the surrounding sidewall.
[0017] As used herein, the term "along the axial direction" refers to a direction parallel to the axis of rotation (X). Correspondingly, relative terms such as "above," "upper," "top," "lower," "below," and "bottom" refer to relative positions along the axis of rotation (X). Correspondingly, the term "radial direction" refers to a direction extending radially from the axis of rotation (X). "Radially inner position" therefore refers to a position closer to the axis of rotation (X) than "radially outer position."
[0018] Contaminants in the gas can include liquid contaminants (such as oil) and soot.
[0019] Therefore, centrifugal separators can be used to separate liquid contaminants (such as oil) from gases. These gases can be crankcase gases from combustion engines. However, centrifugal separators are also suitable for cleaning gases from other sources, such as the environment of machine tools, which typically contain large amounts of liquid contaminants in the form of oil droplets or mist.
[0020] The stationary shell of the centrifuge includes peripheral sidewalls and a first end wall and a second end wall, which enclose the separation space. The stationary shell may have a cylindrical shape with a circular cross-section having a radius R from the axis of rotation (X) to the peripheral sidewalls. This radius R may be constant, at least with respect to the main portion of the periphery of the peripheral sidewalls. The first and second end walls form the upper and lower end walls of the cylindrical shell. The stationary shell may also be slightly tapered. The stationary shell may include more than one layer, such as an outer or inner layer. The innermost surface of the stationary shell may therefore be an object defining the radial and / or axial boundaries of the separation space. The stationary shell may be in two parts, a first part forming the upper portion of the upper end wall and the peripheral sidewalls, and a second part forming the lower end wall and the lower portion of the peripheral sidewalls.
[0021] The gas inlet of the centrifugal separator can be arranged through the upper end wall or through a surrounding side wall close to the upper end wall, thus guiding the gas entering through the gas inlet into the separation space at the top of the separator. The downstream portion of the gas inlet can be centered on the axis of rotation (X). The gas inlet may also include an upstream portion in the form of an inlet conduit. This conduit can extend radially or axially from the centrifugal separator.
[0022] The discharge outlet is located in the lower portion of the stationary shell, such as in the lower end wall or in the lower portion of the surrounding side walls. Therefore, the discharge outlet can be centrally located in an end wall opposite to the end wall through which the inlet is located (or at the inlet location). The centrifugal separator's discharge outlet can also be formed by several point-shaped through-holes in the stationary shell or by a single discharge passage. The discharge outlet can be located at or around the axis of rotation. Alternatively, the discharge outlet can be located in an annular collection groove on the inner end wall of the stationary shell.
[0023] The gas outlet may be in the form of a gas conduit passing through the wall of the stationary shell (such as in the lower portion of the surrounding sidewall of the stationary shell). However, the gas outlet may also be located in the upper portion of the stationary shell.
[0024] The rotating component is arranged to rotate during operation by means of a drive component. The rotating component includes multiple separation components arranged in a separation space. The separation components of the rotating component are examples of surface-enlarging inserts that facilitate the separation of contaminants from the gas. The separation components may be a stack of separation discs. The stacked separation discs may be frustoconical. The frustoconical disc may have a planar portion extending in a plane perpendicular to the axis of rotation, and a frustoconical portion extending upwards or downwards. The planar portion may be closer to the axis of rotation than the frustoconical portion. Furthermore, the stacked discs may be radial discs, wherein substantially the entire disc extends in a plane perpendicular to the axis of rotation.
[0025] It should also be understood that the separating components (such as separating discs) do not necessarily have to be arranged in a stack. The separating space may, for example, include an axial disc or plate extending around the axis of rotation. The axial disc or plate may be planar, that is, extending in a plane parallel to the axis of rotation. The axial disc or plate may also have a slightly or significantly curved shape, such as an arcuate or helical shape, as seen in the radial plane.
[0026] The rotating component is journal-supported within a stationary housing by at least one bearing (such as at least two bearings). Each of the bearings can be held in a separate bearing retainer.
[0027] During operation, the gas to be cleaned can be guided centrally through multiple separating components, such as a stack of separating discs. In such an arrangement, the rotating component may also define a central space formed by at least one through-hole in each of the separating components. This central space is connected to a gas inlet and configured to allow the gas to be cleaned to be conveyed from the gas inlet into gaps between the separating components, such as between the discs in a stack of separating discs. A separating disc that can be used as a separating component may include a substantially flat portion perpendicular to its center of rotation. This portion may include through-holes that form part of the central space.
[0028] Therefore, a centrifugal separator can be configured to guide the gas to be cleaned (such as crankcase gas) from the gas inlet into the central portion of the rotating component. In this way, the rotation of the rotating component can "pump" the crankcase gas from the central portion of the rotating component into the gaps between the separation discs in the stack of separation discs. Thus, the centrifugal separator can operate according to the principle of co-current flow (where gas flows from the radially inner portion to the radially outer portion in the disc stack), which is the opposite of a separator that operates according to the principle of convection (where gas is conducted at the periphery of the rotor into the centrifugal rotor and guided towards the central portion of the rotor).
[0029] The drive component may include, for example, a turbine wheel that rotates by means of an oil jet from the lubrication system of the combustion engine, or a free-jet impeller comprising a backflush disk. However, the drive component may also be independent of the combustion engine and may include an electric motor, a hydraulic motor, or a pneumatic motor. The drive component may be arranged axially downwards within the separation chamber.
[0030] According to a first aspect of the invention, the centrifugal separator further includes at least one guide vane arranged to guide separated liquid impurities on the inner surface of the lower end wall from a radially external position to the discharge outlet.
[0031] Furthermore, the centrifugal separator also includes a radial disk element disposed on top of at least one guide vane. The radial disk element can therefore be a disk that remains stationary during separator operation. Instead of extending radially to the inner surface of the surrounding sidewalls, the radial disk element has small passageways (annular channels) for separating liquid impurities. Thus, separated oil flowing downwards on the inner surface of the surrounding sidewalls due to gravity can pass through the annular channels down to at least one guide vane.
[0032] The first aspect of the invention is based on the insight that radial disk elements arranged on top of one or more guide vanes substantially increase the rigidity of the separator. This is partly due to the disk elements being arranged at a distance from the lower end wall, so that they are not directly heated by the warm oil that may be present in the drive chamber below the separation space. Therefore, in the case of radial disk elements as described in the first aspect of the invention, one or more parts of the centrifugal separator (such as the rotating parts or the stationary shell portion) can be made of polymer material.
[0033] Furthermore, the separator of the first aspect of the invention facilitates a compact structure for centrifugal separators. This is due to the protected oil discharge generated by a radial disk element, which provides a means for arranging the separating components axially close to the lower end wall of the stationary housing. Therefore, the circulating airflow caused by the rotating portion can be prevented from negatively affecting the oil discharge from a radially outer position of the housing (such as at the surrounding sidewalls) to a discharge outlet arranged at a radially inner position. In other words, the radial disk element creates a calm area for liquid impurities as they are discharged from the surrounding sidewalls to the oil discharge section.
[0034] In an embodiment, the distance between the lowest portion of the separating component and the inner surface of the lower end wall is less than 40 mm, such as less than 30 mm. For example, the distance between the lowest portion of the separating component and the inner surface of the lower end wall may be between 5 mm and 40 mm, such as between 5 mm and 30 mm. If the separating component is a stack of separating discs, the lowest portion of the separating component may be located at the outer radius of the lowest separating disc in the disc stack.
[0035] In an embodiment of the first aspect, the radial disk element, the lower end wall, and at least one guide vane form a sandwich structure. Thus, the radial disk element and the lower end wall can form surfaces that bear bending loads (such as tension and compression), while the at least one guide vane forms the core of the sandwich structure that bears shear loads.
[0036] In an embodiment of the first aspect, at least one guide vane extends axially upward from the inner surface of the lower end wall. Therefore, one or more guide vanes may form a protrusion from the inner surface of the lower end wall. The guide vane may be part of the lower end wall of the stationary shell. Thus, one or more guide vanes together with the lower end wall may be a single unit.
[0037] In an embodiment of the first aspect, at least one guide vane extends axially downward from the radial disk element. Therefore, the radial disk element and one or more guide vanes can be formed as a single unit.
[0038] In an embodiment of the first aspect, the radial disk element extends over the top of at least one guide vane, forming a plurality of separate discharge channels between the lower end wall and the radial disk element. The separate discharge channels may extend from a radially outer location to a discharge outlet disposed at a radially inner location.
[0039] Therefore, at least one guide vane, together with the radial disk element and the inner surface of the lower end wall, can form a discharge channel for separating liquid impurities. For example, at least two (such as at least three) separate discharge channels can be formed on the lower end wall. The separate discharge channels can be inclined radially inward toward the discharge outlet to facilitate the transport and discharge of liquid impurities. Since the radial disk element forms a “top cover” for the discharge channels, the liquid impurities in these channels can be shielded from the circulating airflow axially above the radial disk element. Furthermore, the radial disk element can act as a separator for the airflow, causing the gas to move radially outward above the radial disk element (due to the rotating separator) and radially inward below the radial disk element, thereby facilitating the transport of oil toward the discharge outlet.
[0040] In an embodiment of the first aspect, the radial disk element is welded to the top of at least one guide vane. If the radial disk element and the guide vane are plastic, they can be joined by any type of external or internal heating method used to weld thermoplastic materials together. The radial disk element and the guide vane can also be formed by 2K molding.
[0041] At least one guide vane may be at least two, such as at least three, such as at least four guide vanes.
[0042] In an embodiment of the first aspect, at least one guide vane is curved. The at least one guide vane can therefore be curved, as seen in the radial plane, i.e., forming an angle with the radial direction. Thus, the guide vane can be helical or arcuate, as seen in the radial plane. Helical guide vanes can form a continuous or gradually widening curve from the central portion of the inner surface of the lower end wall. As seen radially outward, the curved guide vane can be guided forward in the intended direction of rotation r during centrifugal separator use. This can help guide oil to the discharge outlet when the separator is tilted. However, the curved guide vane can also be guided backward in the intended direction of rotation r during centrifugal separator use.
[0043] In an embodiment of the first aspect, at least one guide vane is straight. The guide vane may be straight in the radial direction, or it may be straight and form an angle with the radial direction.
[0044] In an embodiment of the first aspect, the discharge outlet is disposed in the central portion of the lower end wall. The discharge outlet may be formed, for example, by a plurality of through holes spaced apart around the axis of rotation (X). The inner surface of the lower end wall may be radially inclined inward toward the central portion and the discharge outlet.
[0045] For example, the rotating component can be journal-supported within a stationary housing via upper and lower bearings arranged axially on separate sides of the separating component. The discharge outlet can then be arranged such that separated liquid impurities are discharged through the lower bearing. This facilitates lubrication of the lower bearing.
[0046] In an embodiment of the first aspect, the radial disk element has a radial extension, which is at least a radial extension of a plurality of separating components. Therefore, the annular channel formed between the radial disk element and the inner surface of the surrounding sidewall of the stationary shell can have a width smaller than the distance from the outermost radial portion of the separating component to the inner surface of the surrounding sidewall. Thus, the radial disk element can extend to a position at least 50%, such as at least 75%, such as at least 90%, such as at least 95% of the radial distance of the separation space. The annular channel for separating liquid impurities formed at the inner surface of the surrounding sidewall can have a width of less than 10 mm, such as less than 5 mm (i.e., extending radially).
[0047] In the embodiments of the first aspect, the lower end wall, at least one guide vane, and the radial disk element are made of a polymer material. As discussed above, one or more of the radial disk element, the lower end wall of the stationary shell, and the rotating components can be made of a polymer material (such as plastic) due to the stability and stiffness provided by the radial disk element. This facilitates the production of the centrifuge.
[0048] In an embodiment of the first aspect, the gas outlet is arranged on the upper half of the stationary shell. For example, the gas outlet may be arranged in the upper portion of the surrounding sidewall of the stationary shell or in the upper end wall of the stationary shell.
[0049] In an embodiment of the first aspect, the drive component is a turbine impeller configured to rotate by means of an oil jet from the lubrication system of the combustion engine. As mentioned above, the use of a radial disk element can then be advantageous because it avoids direct contact with any drive chamber containing warm oil.
[0050] In embodiments of the first aspect, the multiple separating components are a stack of separating discs, such as a stack of truncated conical separating discs. Such discs may have an outer radius and an inner radius, thus forming a central opening within the disc. The truncated conical separating disc may include a flat portion extending perpendicular to the axis of rotation (X), and a conical portion extending outward and downward from the flat portion. The opening is a flat portion that serves as a central space within the centrifuge, into which the gas to be cleaned is guided from a gas inlet. Thus, the gas to be cleaned can be guided into the central space and then into the gaps formed between the discs in the disc stack. As a supplement or alternative, the central space may also be formed radially within the inner radius of the disc.
[0051] As a second aspect of the invention, a method for cleaning a gas containing pollutants is provided, the method comprising:
[0052] During the rotation of the rotating component, the gas containing contaminants is directed to the centrifugal separator according to the first aspect above.
[0053] Clean gas is discharged from the gas outlet, and
[0054] Pollutants are discharged from the emission outlet.
[0055] Contaminants in the gas can include liquid contaminants (such as oil) and soot.
[0056] This aspect generally presents the same or corresponding advantages as the preceding aspects. The effects and features of the second aspect are largely similar to those described above with respect to the first aspect. The embodiments mentioned with respect to the first aspect are largely compatible with the second aspect.
[0057] The inventors also recognized that having only guide vanes and omitting radial disk elements can still provide a certain beneficial effect. Therefore, as an additional aspect of the invention, a centrifugal separator for cleaning gases containing contaminants is provided, the centrifugal separator comprising...
[0058] A stationary shell surrounds a separation space, allowing airflow through it. The stationary shell includes surrounding sidewalls, an upper end wall, and a lower end wall.
[0059] A gas inlet extends through the stationary housing and allows for the supply of gas to be cleaned.
[0060] A rotating component comprising a plurality of separating components arranged in the separating space and configured to rotate about a rotation axis (X);
[0061] A gas outlet, disposed within the stationary shell and configured to allow the discharge of clean gas, includes an outlet opening through the wall of the stationary shell.
[0062] An exhaust outlet is located in the lower portion of the stationary shell and configured to allow the discharge of liquid contaminants separated from the gas to be cleaned.
[0063] A drive component for rotating the rotating component;
[0064] The centrifugal separator also includes at least one guide vane, which is arranged to guide separated liquid impurities on the inner surface of the lower end wall from a radially external position to the discharge outlet.
[0065] All the features of this aspect are the same as those disclosed above with respect to the first aspect. Therefore, except for the absence of radial disk elements, the centrifugal separator of this additional aspect may be the same as the centrifugal separator of the first aspect.
[0066] During operation, the rotation of the disk stack generates a swirling airflow that causes the oil to move in a circular motion around the stationary shell, even when tilted. By using only guide vanes, the separated oil can still be guided in the slots between the vanes and discharged through the exhaust outlet, even at a high tilt. The guide vanes thus provide a low-pressure zone where oil can accumulate and pour towards the exhaust outlet. The guide vanes themselves further strengthen the stationary shell.
[0067] The guide vanes can therefore extend axially upward from the inner surface of the lower end wall.
[0068] The guide vanes can be straight or curved, as seen in the radial plane. Furthermore, the guide vanes can have the same axial height throughout their radial extension, or the axial height can vary. For example, the axial height can be greater in the radially intermediate portion of the guide vane compared to the radially inner and outer portions. Therefore, the guide vanes can be curved, as seen in the axial plane.
[0069] For example, a centrifugal separator may include at least four guide vanes, such as at least eight, at least twelve, or at least sixteen guide vanes. Attached Figure Description
[0070] The foregoing and additional objectives, features, and advantages of the present invention will be better understood from the following illustrative and non-limiting detailed description, with reference to the accompanying drawings. In the drawings, similar reference numerals will be used for similar elements unless otherwise stated.
[0071] Figure 1 A schematic cross-sectional view of an embodiment of a centrifugal separator for cleaning gases is shown.
[0072] Figure 2 Show Figure 1 A close-up view of the lower wall of a centrifuge.
[0073] Figure 3 As shown Figure 2 However, the close-up view of the lower end wall of the radial disk element has been removed.
[0074] Figure 4 An additional embodiment is shown in which the centrifugal separator has guide vanes but no radial disk element.
[0075] Figure 5 Show Figure 4 A top view of the lower end wall of the stationary shell of the embodiment shown in the figure. Detailed Implementation
[0076] The centrifugal separator according to this disclosure will be further illustrated by referring to the accompanying drawings and the following description.
[0077] Figure 1 A cross-section of a centrifugal separator 1 according to this disclosure is shown. The centrifugal separator 1 includes a stationary housing 2 configured to be mounted in a suitable location (such as on top of or on the side of a combustion engine) to a combustion engine (not disclosed), particularly a diesel engine.
[0078] It should be noted that centrifugal separator 1 is also suitable for cleaning gases from sources other than combustion engines (e.g., environments of mechanical tools that typically contain large amounts of liquid contaminants in the form of oil droplets or mist).
[0079] The stationary shell 2 surrounds the separation space 3, allowing airflow through the separation space 3. The stationary shell 2 includes a surrounding side wall 4, an upper end wall 5, and a lower end wall 6, or is formed by the surrounding side wall 4, the upper end wall 5, and the lower end wall 6.
[0080] The centrifugal separator includes a rotating component 7 arranged to rotate about a rotation axis (X). It should be noted that the stationary shell 2 is stationary relative to the rotating component 7 (and preferably relative to the combustion engine to which it can be mounted).
[0081] The stationary shell 2 has a radius from the axis of rotation (X) to the surrounding sidewall 4, which is constant at least with respect to the main portion of the periphery of the surrounding sidewall 4. The surrounding sidewall 4 therefore has a circular or substantially circular cross-section.
[0082] The rotating component 7 includes a spindle 8 and a stack of separation discs 9 attached to the spindle 8. All the stacked separation discs 9 are located within the separation space 3 between the top disc 10 and the lower end plate 11.
[0083] The spindle 8 (and therefore the rotating component 7) is rotatably supported in the stationary housing 2 by means of an upper bearing 12 and a lower bearing 13, with one bearing arranged on each axial side of the stack of the separating discs 9.
[0084] The separation disc 9 of the disc stack is truncated conical and extends outward and downward from the spindle 8. The separation disc thus includes a flat portion 9a extending perpendicular to the axis of rotation (X), and a conical portion 9b extending outward and downward from the flat portion 9a.
[0085] It should be noted that the separator disc can also extend outward and upward (or even radially).
[0086] The stacked separator discs 9 are positioned at a distance from each other by means of spacer members (not disclosed) to form gaps 14 between adjacent separator discs 9, that is, gaps 14 between each pair of adjacent separator discs 9. The axial thickness of each gap 14 may be, for example, about 1-2 mm.
[0087] The stacked separation disks 9 can be made of plastic or metal. The number of separation disks 9 in the stack is typically higher than [a certain number]. Figure 1 As indicated in the instructions, and may be, for example, 50 to 100 separation discs (depending on the size of the centrifuge).
[0088] Centrifugal separator 1 includes an oil nozzle 21 arranged for connection to the engine oil circuit of an internal combustion engine. During operation of the internal combustion engine, oil is pumped through the oil nozzle 21 to an impeller 22 connected to a spindle 8, thereby rotating the rotating component 7 (and thus the stack of separation discs 9). The turbine impeller 22 is arranged in a drive chamber 30, which is axially downward of the separation space 3.
[0089] As an alternative, the centrifuge 1 may include an electric motor arranged to rotate the spindle 8 and the rotating component 7. As another alternative, the centrifuge 1 may include a turbine impeller connected to the spindle 8, wherein the turbine impeller is arranged to be driven by exhaust gases from an internal combustion engine to rotate the spindle 8 and the rotating component 7. The rotating component 7 may also be arranged for rotation by a mechanical drive unit. Therefore, the centrifuge may include a mechanical drive unit for rotating the rotating component.
[0090] The rotating component 7 defines a central space 15 within the separation space 3. The central space 15 is formed by through-holes in each of the stacked separation disks 9. Figure 1 In one embodiment, the central space 15 is formed by a plurality of through-holes, each extending through the top disk 10 and through each of the separation disks, but not through the lower end plate 11. The through-holes are arranged in the flat portion 9a of the separation disk.
[0091] Gas inlet 20 is used to supply the gas to be cleaned. Gas inlet 20 extends through the stationary housing 2, and more precisely through the upper end wall 5. Gas inlet 20 is formed by an axially extending inlet conduit 18 (which forms the upstream portion) and a through passage 21 (which forms the downstream portion of inlet 20). Through passage 21 is arranged radially outward of the upper bearing 12, through which the inlet conduit 18 communicates with the central space 15.
[0092] Gas inlet 20 communicates with central space 15, allowing gas to be cleaned to be delivered from inlet 20 through central space 15 to the gap 14 of the stack of separator discs 9. Gas inlet 20 is configured to communicate with the crankcase of the combustion engine or any other source via inlet conduit 18, which allows crankcase gas to be supplied from the crankcase to gas inlet 20 and further to central space 15 and gap 14, as explained above.
[0093] Centrifugal separator 1 includes a discharge outlet 29 disposed in the lower portion of separation space 3 and configured to allow the discharge of liquid contaminants separated from the gas. In this embodiment, discharge outlet 29 is in the form of a through-hole disposed in lower end wall 6, allowing the separated liquid contaminants to flow through lower bearing 13 as they are discharged from separation space 3. The separated oil (and other particles and / or substances) is directed to oil outlet 25 of centrifugal separator 1, and the separated oil (and other particles and / or substances) together with oil from oil nozzle 21 used to drive impeller 22 can be directed back to the engine oil circuit of internal combustion engine.
[0094] In this example, the gas outlet 28 of the centrifuge 1 is located in the upper portion of the stationary shell 2 and is configured to allow the discharge of clean gas. The gas outlet 28 includes an outlet conduit that passes through the surrounding sidewall 4 of the stationary shell 2. In this embodiment, the gas outlet 28 is located in the upper portion of the surrounding sidewall 4, but the gas outlet 28 may also be located in the upper end wall 5.
[0095] In such Figure 1 During operation of the centrifugal separator shown, the rotating component 7 is kept rotating by an oil nozzle 21 that supplies oil relative to the impeller 22. For example, the rotational speed can be in the range of 7500-12000 rpm.
[0096] Contaminated gas (e.g., crankcase gas from the crankcase of an internal combustion engine) is supplied to gas inlet 20 via conduit 18. This gas is further conducted into central space 15 and from there into and through gap 14 between stacked separator discs 9. Due to the rotation of rotating component 7, the gas is driven to rotate, thereby further pumped radially outward through the gap or opening 14.
[0097] During gas rotation in gap 14, solid or liquid particles (such as oil) suspended in the gas are separated from it. The particles settle on the inner side of the conical portion 9b of the separation disc and then slide or run radially outward thereafter. As the particles and / or droplets reach the radially outer edge of the separation disc 9, they are thrown off the rotating component 7 and impact the inner surface 4a of the surrounding sidewall 4. The separated oil particles can form a film on the inner surface 4a of the stationary shell 2. From there, the oil can be pulled downward by gravity to the lower end wall 6 and then exit the separation space 3 through the discharge outlet 29. For this purpose, the inner surface 6a of the lower end wall can be radially inwardly inclined so that the oil leaving the surrounding inner wall of the stationary shell 2 can be pulled towards the discharge outlet 29 by gravity. The path of contaminants in the gas is... Figure 1 It is schematically indicated by the arrow "D".
[0098] Clean gas, having had particles removed and exiting the stack of separation discs 9, leaves the stationary shell 2 through gas outlet 28. The path of the gas through centrifugal separator 1 is... Figure 1 It is schematically indicated by the arrow "C".
[0099] The lower end wall 6 of the stationary shell 2 also includes a plurality of guide vanes 40 extending axially upward from the inner surface 6a of the lower end wall. Thus, the guide vanes 40 form protrusions from the inner surface 6a of the lower end wall 6 and are arranged to guide separated liquid impurities (such as oil) from a radially external position to the discharge outlet 29. In other words, oil pulled downward by gravity on the inner surface 4a of the surrounding sidewall 4 is further guided by the guide vanes on the inner surface 6a of the lower end wall to the discharge outlet 29. In this example, the guide vanes are curved and... Figure 2 and Figure 3 As seen in more detail below, the discharge outlet 29 is located in the central portion of the lower end wall 6, and in this example, it is arranged such that separated liquid impurities are discharged through the lower bearing 13.
[0100] There is also a radial disk element 50 disposed on top of the guide vane 40, such that the radial disk element 50, the lower end wall 6, and the guide vane 40 form a sandwich structure, as seen in the axial plane. This provides a robust and more rigid structure, thus providing a structure for making at least one or all of the lower end wall 6, the guide vane 40, and the radial disk element 50 made of a polymeric material (such as plastic), while still giving the entire centrifuge 1 overall rigidity, allowing it to be used in harsh and hot environments at the engine or engine block. In this example, the radial disk element 50 is welded to the top of the guide vane 40.
[0101] Furthermore, because the radial disk element 50 does not extend radially into the separation space to the inner surface 4a of the surrounding sidewall 4 (i.e., to a position radially inward from the surrounding sidewall 4), an annular channel 60 for separating liquid impurities is formed at the inner surface 4a of the surrounding sidewall 4. Due to the radial disk element 50, a calm zone for separating liquid impurities is formed in the resulting sandwich structure. This means that the separated oil guided on the lower end wall is shielded from the circulating gas above the radial disk element 50.
[0102] Figure 2 and Figure 3 The radial disk element 50 and the resulting sandwich structure are shown in more detail. Figure 3 and Figure 2 The same, but the radial disk element 50 is removed to further reveal the separate exhaust channel 41. Therefore, as in Figure 2 and Figure 3 As seen in the image, the radial disk element 50 extends over the top of the guide vane 40, forming a plurality of individual discharge channels 41 on the lower end wall 6. The individual discharge channels 41 extend from a radially outer position to a discharge outlet 29 arranged at a radially inner position. Separated oil can thus be guided in the individual discharge channels 41, such as... Figure 3 This is indicated by the arrow "D", thus preventing the re-entry of circulating gas into the radial disk element axially upwards.
[0103] As in Figure 2 and Figure 3 As seen in the perspective view, at least one guide vane 40 is curved, as seen in the radial plane. This means that the resulting discharge channel 41 is also curved or spiral-shaped. As seen radially outward, the curved guide vane 40 in this example is guided rearward in the intended direction of rotation r during the use of the centrifuge 1.
[0104] However, one or more guide vanes 40 may also be straight (e.g., straight in the radial direction, or straight and at an angle to the radial direction), and can still form a sandwich structure together with the radial disk element 50 and the lower end wall 6.
[0105] One or more guide vanes 40 may be shaped such that the resulting discharge channel 41 becomes thinner as it extends radially inward.
[0106] The radial disk element 50 is arranged close to the lower end wall 6, allowing for a compact separator structure. The radial disk element has a central through-hole 51 through which the rotating component 7 extends. Furthermore, the radial disk element 50 has radial extensions, which are at least radial extensions of the disk stack. Figure 2 As shown, the disk stack extends to a radial position X1, while the radial disk element 50 extends to a radial position X2, where X2 is greater than X1. This provides a radially thin annular channel 60 between the radial disk element 50 and the inner surface 4a surrounding the sidewall 4.
[0107] Because of the radial disk element 50, the disk stack can be arranged with a distance Y to the lower end wall 6, where the distance Y is less than 40 mm, such as less than 30 mm. Figure 2 As shown in the figure. However, the distance Y can be greater than 5 mm, such as between 5 and 40 mm. The distance Y is therefore the axial distance between the radially outermost portion of the lower end plate 11 and the lower end wall 6.
[0108] Therefore, the radial disk element can be arranged with a distance of 5-40 mm (such as 10-30 mm) from the lower end wall.
[0109] In addition, the radial disk element 50 may have a thickness between 1 and 3 mm.
[0110] As discussed above regarding additional aspects, there can be beneficial effects in the case of having only guide components and no radial disk elements. Figure 4 Such embodiments are disclosed in the literature. Figure 4 The lower end wall 6 of the stationary shell of centrifuge 1 is shown. Guide vanes 40 extend from the inner surface 6a of the lower end wall 6 of the stationary shell. Figure 4 Two examples of guide vanes 40 that are straight in the radial direction are shown. Figure 4 On the upper left, the guide vane 40 has the same axial height throughout its radial length. On the upper right, the guide vane 40 has an axial height that varies throughout its radial extension. The guide vane 40 has a radially inner portion and a radially outer portion 62. Therefore, the radially intermediate portion 61, arranged radially between the inner and outer portions 62, has a higher axial height than both the inner and outer portions. However, the axial section remains smooth, i.e., slightly curved, as seen in the axial plane.
[0111] Figure 5A top view of the inner surface 6a of the lower end wall 6 is shown. Therefore, the guide vanes 40 create a lower pressure zone between the vanes 40, allowing the separated oil at the bottom of the centrifugal separator to drain out via the discharge outlet 29, as indicated by arrow "D". As seen in the radial plane, Figure 4 and Figure 5 The guide vanes 40 shown are all straight. However, the guide vanes can also be bent in the radial plane, as described above. Figure 1-3 As shown.
[0112] This invention is not limited to the disclosed embodiments, but can be varied and modified within the scope of the claims set forth below. The invention is not limited to the orientation of the rotation axis (X) disclosed in the figures. The term "centrifuge" also includes centrifuges having a substantially horizontally oriented rotation axis. In the foregoing, the inventive concept has been described primarily with reference to a limited number of examples. However, as will readily apparent to those skilled in the art, other examples besides those disclosed above are equally possible within the scope of the inventive concept as defined by the appended claims.
Claims
1. A centrifugal separator (1) for cleaning gases containing contaminants, said centrifugal separator (1) comprising: A stationary shell (2) surrounds a separation space (3) and allows airflow through the separation space (3). The stationary shell includes surrounding sidewalls (4), an upper end wall (5), and a lower end wall (6). A gas inlet (20) extends through the stationary shell (2) and allows the supply of gas to be cleaned. A rotating component (7) comprising a plurality of separating components (9) arranged in the separating space (3) and arranged to rotate about a rotation axis (X); A gas outlet (28) is disposed in the stationary housing (2) and configured to allow the discharge of clean gas, and includes an outlet opening through the wall of the stationary housing (2). The discharge outlet (29) is arranged in the lower part of the stationary shell (2) and configured to allow the discharge of liquid contaminants separated from the gas to be cleaned; A driving component (22) is used to rotate the rotating component (7); The centrifuge (1) further includes at least one guide vane (40) arranged to guide separated liquid impurities on the inner surface (6a) of the lower end wall (6) from a radially external position to the discharge outlet (29). The centrifugal separator (1) further includes a radial disk element (50) disposed on the top of the at least one guide vane (40), wherein the radial disk element (50) extends radially in the separation space (3) to a position radially inward from the surrounding sidewall (4), thereby forming an annular channel (60) for separating liquid impurities at the inner surface (4a) of the surrounding sidewall (4).
2. The centrifuge (1) according to claim 1, wherein, The radial disk element (50), the lower end wall (6), and the at least one guide blade (40) form a sandwich structure.
3. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The at least one guide vane (40) extends axially upward from the inner surface (6a) of the lower end wall (6).
4. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The at least one guide vane (40) extends axially downward from the radial disk element (50).
5. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The radial disk element (50) extends on top of the at least one guide vane (40) such that a plurality of individual discharge channels (41) are formed between the lower end wall (6) and the radial disk element (50), wherein the individual discharge channels (41) extend from a radially outer position to the discharge outlet (29) arranged at a radially inner position.
6. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The radial disk element (50) is welded to the top of the at least one guide vane (40).
7. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, At least one guide vane (40) is curved.
8. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The at least one guide vane (40) is straight.
9. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The discharge outlet (29) is located in the central portion of the lower end wall (6).
10. The centrifuge (1) according to claim 9, wherein, The rotating component (7) is journal-supported within the stationary housing (2) via an upper bearing (12) and a lower bearing (13) arranged axially on separate sides of the separating component (9), wherein the discharge outlet (29) is arranged such that separated liquid impurities are discharged through the lower bearing (13).
11. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The radial disk element (50) has a radial extension, which is at least a radial extension of the plurality of separate components (9).
12. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The lower end wall (6), the at least one guide vane (40), and the radial disk element (50) are made of polymer material.
13. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The gas outlet (28) is located on the upper half of the stationary shell (2).
14. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The plurality of separation components (9) are a stack of separation discs.
15. The centrifugal separator (1) according to any one of claims 1 or 2, wherein, The drive component (22) is a turbine impeller configured to rotate by means of an oil jet from the lubrication system of the combustion engine, or the drive component (22) is an electric motor.