Centrifugal separator for separating liquid from moisture
By designing a centrifugal separator of an annular inner shell and an outer shell, the flow path and structural design are optimized, and the problem of low separation efficiency between liquid and pressurized gas in the prior art is solved, and efficient separation effect is achieved within a wide flow rate and a wide pressure range.
Patent Information
- Application Number
- CN202380052787.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-07-11
- Filing Date
- 2023-07-04
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art is difficult to achieve efficient separation of liquid and booster gas within a wide flow rate range and/or a wide pressure level range.
A centrifugal separator is designed, including an annular inner shell and an outer shell. By optimizing the flow path and structural design, the upward circulation of gas and the effective separation and discharge of liquids are achieved.
Efficient separation of liquid from gas over a wide flow rate and a wide pressure range of gas is achieved without moving parts, capable of receiving variable flow rate and pressure levels of gas, and ensuring that the separated liquid does not re-enter the gas flow.
Smart Images
Figure CN119522137A_ABST
Abstract
Description
Technical Field
[0001] The present invention generally relates to a pressure fluid processing system arranged for separating liquid from wet gas, ie a fluid separator, wherein the separation of the fluid is based on the centrifugal principle.
[0002] The invention particularly relates to a centrifugal separator for separating liquid from wet gas, wherein the separator comprises an outer housing, the outer housing comprising a liquid outlet opening at the bottom of the outer housing, a gas outlet opening at the top of the outer housing, wherein the centrifugal separator comprises an inlet opening for wet gas, the inlet opening being located between the liquid outlet opening and the gas outlet opening of the outer housing.
[0003] Such a centrifugal separator is particularly advantageous in combination with combustion engine components and pneumatic machines / tools having pneumatic drives / components, in particular when wet gases are pressurized. Background Art
[0004] The present invention is based on the fact that many known applications in various technical fields use pressurized fluids (gases, including pressurized gases) in pressure fluid circuits in order to operate / drive pneumatic devices or equipment to perform useful tasks. Therefore, many applications / devices in various technical fields use internal elements / components that move during the operation of the device, wherein the application / device uses gas (including pressurized gas) for its operation / in its operation. Such applications / devices usually experience mixing of lubricating liquid with pressure fluid (gas with increased pressure). The mixing can be intentional in order to deliver the lubricating liquid to the moving internal elements through the pressure fluid (gas), thereby providing cooling to parts of the device or assembly, etc. by controlled leakage at different seals or by injecting the lubricating liquid into the gas circuit. In other cases, the mixing of gas and liquid is unintentional.
[0005] In some applications, the pressurized fluid (gas) is circulated / reused, so-called closed pressure fluid circuits, and in some applications, the gas (which includes pressurized gas) is released / vented after use. In both cases, whether the mixing is intentional and / or unintentional, it is usually necessary to separate the excess fluid from the gas during recirculation or before the gas is discharged. In applications with closed pressure fluid circuits, too high a liquid content in the gas will have a negative impact on the operation of the device, and too high a liquid content in the exhaust gas will have a negative impact on the working environment and / or nature. This is especially true when the gas is pressurized, because liquids, unlike gases, are incompressible.
[0006] For example, such centrifugal separators are of great value for combustion engines and pneumatic machines / tools having pneumatic devices / components which utilize a pressurized fluid in a closed pressure fluid circuit and a pressure differential across the pneumatic device in order to operate / drive the pneumatic device, e.g. to move an element back and forth or to rotate an element.
[0007] The inventors have not found any known fluid separator that can separate liquid from pressurized gas with high separation capacity over a wide range of flow rates of the gas through the separator and / or over a wide range of pressure levels of the gas. Some known applications can provide high separation capacity for a fixed / predetermined flow rate of the gas and / or a fixed / predetermined pressure level of the gas.
[0008] Purpose of the Invention
[0009] The object of the present invention is to eliminate the disadvantages and drawbacks of previously known centrifugal separators and to provide an improved centrifugal separator. The main object of the present invention is to provide an improved centrifugal separator of the initially defined type, wherein the separation capacity is high over a wide range of flow rates of the gas passing through the separator. Another object of the present invention is to provide a centrifugal separator, wherein the separation capacity is high over a wide range of pressure levels of the gas. Another object of the present invention is to provide a centrifugal separator, which has no moving parts / elements. Another object of the present invention is to provide a centrifugal separator, which is capable of receiving a variable flow rate of the gas and / or a variable pressure level of the gas. Another object of the present invention is to provide a centrifugal separator, wherein the liquid separated in the inner casing does not re-enter the gas flow. Summary of the invention
[0010] According to the present invention, at least the primary object is achieved by the initially defined centrifugal separator having the features defined in the independent claim. Preferred embodiments of the invention are further defined in the dependent claims.
[0011] According to the present invention there is provided a centrifugal separator of the initially defined type, characterised in that it also comprises:
[0012] - an annular inner casing located within the outer casing forming an intermediate volume delimited by the inner casing and the outer casing, wherein an inlet opening of the centrifugal separator extends to the inner casing, and the inner casing comprises:
[0013] - an inlet hole of an inlet opening;
[0014] - a lower liquid outlet opening, which is located at the bottom of the inner housing; and
[0015] - annular upper edge,
[0016] - wherein the inner surface of the top portion of the outer shell and the upper edge of the inner shell are located adjacent to each other and together define an upper liquid outlet opening of the inner shell,
[0017] - wherein the gas outlet opening of the outer casing is located radially inside the upper edge of the inner casing, and
[0018] - wherein the upper liquid outlet opening of the inner housing is connected to the liquid outlet opening of the outer housing via an intermediate volume.
[0019] Thus, the present invention is based on the insight of having a design / construction of a centrifugal separator which provides an optimized flow path for the gas through the separator with the goal of not losing pressure or flow rate while providing efficient separation of liquid from wet gas. The separator design of the present invention provides a flow direction of the gas from the inlet opening of the inner shell directly towards the gas outlet opening located at the top of the outer shell, i.e. a flow direction giving an upward circulation of the gas from the inlet opening of the inner shell directly towards the gas outlet opening located at the top of the outer shell.
[0020] According to various embodiments of the present invention, the increased pressure of the pressurized gas and the flow rate of the gas will force the liquid outward to the inner surface of the inner shell, wherein the liquid will begin to accumulate and a portion of the liquid will flow downward toward the lower liquid opening of the inner shell, and a portion of the liquid will follow the gas flow and move upward toward the upper liquid opening of the inner shell.
[0021] According to various embodiments of the present invention, the inner surface of the top portion of the outer shell includes an annular ridge that protrudes downward relative to an adjacent portion of the inner surface of the top portion of the outer shell, and the annular ridge of the outer shell and the upper edge of the inner shell are positioned adjacent to each other and together define an upper liquid outlet opening of the inner shell. Thus, a more effective separation of liquid from moisture is provided.
[0022] According to various embodiments of the present invention, the joint transverse center axis of the inlet hole of the inner casing and the inlet opening of the centrifugal separator is arranged to be radially offset from the axial center axis of the inner casing. Therefore, the wet gas enters the inner casing in a tangential direction, thereby strengthening the circulation flow and thus providing a more effective separation of liquid from the wet gas.
[0023] According to various embodiments of the invention, the lower liquid outlet opening of the inner housing is connected to the liquid outlet opening of the outer housing through the intermediate volume. Thus, all liquid separated from the wet gas will leave the centrifugal separator through the liquid outlet opening of the outer housing. The separated liquid located in the intermediate volume is discharged from the liquid outlet opening of the outer housing by the pressure of the pressurized gas and by gravity.
[0024] According to various embodiments of the invention, the inner housing has an annular main wall portion comprising an inlet opening and a tapered bottom wall portion comprising a lower liquid outlet opening. The annular main wall portion of the inner housing is arranged to produce as low a flow resistance as possible to the flow of the pressurized gas, i.e., does not comprise sharp edges / corners. The tapered bottom wall portion of the inner housing is arranged such that the separated liquid accumulates in the inner housing so as to obtain a clear liquid flow out through the lower liquid outlet opening of the inner housing.
[0025] According to various embodiments of the present invention, the inlet hole of the inner shell is located at the lower end of the main wall portion. A local elevated pressure is formed at the tapered bottom wall portion just below the inlet hole and gives a more pronounced flow direction for the gas to circulate upward from the inlet hole of the inner shell.
[0026] According to various embodiments of the invention, the main wall portion of the inner housing has a constant cross-sectional area in the axial direction or has a cross-sectional area that increases in the upward direction. Thus, a more pronounced flow direction is given to the gas circulating upward from the inlet opening of the inner housing.
[0027] According to various embodiments of the invention, the main wall portion of the inner housing has a circular cross section or an elliptical cross section, seen from above. This provides the lowest possible flow resistance for the gas.
[0028] According to various embodiments of the invention, the outer housing has a main wall portion comprising an inlet opening of the centrifugal separator and a tapered bottom wall portion comprising a liquid outlet. The tapered bottom wall portion of the outer housing is arranged such that the separated liquid accumulates in the outer housing so as to obtain a significant liquid flow out through a lower liquid outlet opening of the outer housing.
[0029] According to various embodiments of the invention, the outer casing and the inner casing are coaxial.Thereby, the flow and pressure characteristics in the intermediate volume are balanced in the circumferential direction of the centrifugal separator.
[0030] According to various embodiments of the present invention, the upper edge of the inner shell is located radially outside the apex of the annular ridge of the outer shell. Thus, the stagnation area is created by the annular ridge to separate the gas flow from the liquid flow in an efficient manner and to obtain a high separation capacity also at high flow rates of the gas.
[0031] According to various embodiments of the present invention, the upper edge of the inner shell is located radially outside the annular ridge of the outer shell. Therefore, a stagnation area is generated at the annular ridge, which separates the gas flow from the liquid flow in an effective manner and also obtains a high separation capacity at high flow rates of the gas.
[0032] According to various embodiments of the invention, the upper edge of the inner shell is located at the same height as or above the apex of the annular ridge of the outer shell.Thereby, a more efficient separation of liquid from gas is provided.
[0033] According to various embodiments of the present invention, the cross-sectional area of the gas outlet opening of the outer shell is larger than the cross-sectional area of the lower liquid outlet opening of the inner shell, thereby enhancing the effect of guiding the gas flow upward in the inner shell.
[0034] Further advantages and features of the invention are apparent from the other dependent claims and from the following detailed description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The above and other features and advantages of the present invention will be more fully understood through the following detailed description of the preferred embodiments in conjunction with the accompanying drawings, in which:
[0036] Figure 1 is a schematic side sectional view of a centrifugal separator of the present invention,
[0037] Figure 2 is a schematic cross-sectional view from above of a centrifugal separator of the present invention,
[0038] Figure 3 is a schematic cross-sectional view from above of a centrifugal separator of the present invention,
[0039] Figure 4 is a schematic side cross-sectional view of a centrifugal separator of the present invention, and
[0040] Figure 5 It is a schematic side sectional view of the centrifugal separator of the present invention. DETAILED DESCRIPTION
[0041] First reference Figures 1 to 3 , Figures 1 to 3 Various embodiments of a centrifugal separator (generally designated 1) of the present invention are disclosed, which is arranged for separating liquid from wet gas (including pressurized gas). Thus, wet gas is supplied to the separator 1, and dry gas and liquid are thus discharged from the separator 1 separately from each other.
[0042] The gas (which includes pressurized gas) is constituted, for example, by a pressure fluid of a pneumatically operated device. The pressure fluid is arranged to perform a task / work, such as displacing an element / component. The pneumatically operated device may be constituted by a combustion engine assembly or a pneumatic machine having a pneumatically driven / operated component / tool. The pressure fluid (i.e., gas, which includes pressurized gas) flows through the centrifugal separator of the present invention and to a pneumatically driven component / tool, such as an actuator arranged to displace a gas exchange valve of a camshaft free piston engine, through a pressure fluid circuit. Therefore, the present invention is preferably intended to be used in a pressure fluid system comprising a pressure fluid circuit, wherein the pressure fluid circuit comprises a gas compressor (for increasing the pressure of the gas), a centrifugal separator 1 of the present invention, and a tool connected in series. The gas compressor generates heat when in operation, and this heat generation is reduced by having a large amount of lubricating liquid (i.e., mist) in the gas, however, when the pressurized wet gas comprises too much liquid, the tool cannot operate optimally. Other applications can be envisioned, and the present invention is not limited to use with the applications described. The pressure level of the gas may be, for example, up to 8-30 bar.
[0043] The centrifugal separator 1 comprises an outer casing 2 and an annular inner casing 3 located inside the outer casing 2. The annular inner casing 3 and the outer casing 2 together create an intermediate chamber delimited by the inner casing 3 and the outer casing 2. According to various embodiments, the outer casing 2 and the inner casing 3 are coaxial.
[0044] According to various embodiments, the inner diameter of the outer shell 2 is equal to or greater than 40 mm and equal to or less than 80 mm, preferably equal to or greater than 50 mm and equal to or less than 70 mm.
[0045] The outer shell 2 comprises a liquid outlet opening 4 at the bottom of the outer shell 2, a gas outlet opening 5 at the top of the outer shell 2, and the centrifugal separator 1 comprises an inlet opening 6 for wet gas and / or wet pressurized gas (i.e. a mixture of gas and liquid). In the axial / vertical direction of the separator 1, the inlet opening 6 of the centrifugal separator 1 is located between the liquid outlet opening 4 and the gas outlet opening 5 of the outer shell 2. The opening is provided with a connecting device so that a pipe / conduit is connected to the separator 1. Preferably, the connecting device is a threaded connecting device. According to various embodiments, the inner diameter of the inlet opening 6 is about 15 mm. According to various embodiments, the inner diameter of the liquid outlet opening 4 is about six mm. According to various embodiments, the inlet diameter of the gas outlet opening 5 is about 15-23 mm.
[0046] According to various embodiments, the liquid outlet opening 4 and / or the gas outlet opening 5 are located at the axial center axis of the outer housing 2. The outer housing 2 is preferably divided into a top portion and a bottom portion, which are connected to each other so as to be inserted into the inner housing 3. The outer housing 2 has a main wall portion 7 including an inlet opening 6, a tapered bottom wall portion 8 including the liquid outlet opening 4, and a top portion 9 including the gas outlet opening 5. The main wall portion 7 extends between the bottom wall portion 8 and the top portion 9. The tapering of the bottom wall portion 8 reduces the cross-sectional area of the outer housing 2 in the downward direction from the main wall portion 7 to the liquid outlet opening 4. Therefore, the bottom wall portion 8 is funnel-shaped with straight or curved sides.
[0047] According to various embodiments, the cross section of the main wall portion 7 of the outer housing 2 has an annular basic shape, i.e. circular, elliptical, etc. Preferably, the cross-sectional area of the main wall portion 7 is constant in the axial direction. According to various embodiments, the main wall portion 7 of the outer housing 2 has at least an axial portion having a polygonal basic shape, i.e. a cross section, e.g. six or eight sides, so that the separator 1 can be clamped / fixed using a wrench or the like.
[0048] The inner shell 3 comprises: an inlet hole 10, wherein the inlet opening 6 of the centrifugal separator 1 extends to the inlet hole 10 of the inner shell 3; a lower liquid outlet opening 11, which is located at the bottom of the inner shell 3; and an annular upper edge 12. The inlet hole 10 of the inner shell 3 is located between the liquid outlet opening 11 and the upper edge 12, as seen in the axial / vertical direction of the separator 1. The inner shell 3 has an annular main wall portion 13 including the inlet hole 10 and a tapered bottom wall portion 14 including the liquid outlet opening 11. The upper edge 12 terminates the main wall portion 13 of the inner shell 3, and the main wall portion 13 extends between the bottom wall portion 14 and the upper edge 12. The tapering of the bottom wall portion 14 reduces the cross-sectional area of the inner shell 3 from the main wall portion 13 to the liquid outlet opening 11 in the downward direction. Therefore, the bottom wall portion 14 is funnel-shaped with straight or curved sides. Therefore, there will be a locally increased pressure at the bottom wall portion 14, and the wet gas flow will be directed upward in the inner shell. The main wall portion 13 preferably has a reduced thickness near the upper edge 12 , ie the upper edge 12 is thinned.
[0049] The inner shell 3 is annular, meaning that the cross-section of the main wall portion 13 and the upper edge 12 has an annular basic shape, i.e. circular, elliptical, etc., in order to provide the gas with as low a flow resistance as possible. The inlet opening 10 of the inner shell 3 is preferably located at the lower end of the main wall portion 13, i.e. adjacent to the bottom wall portion 14. The transverse center axis of the joint of the inlet opening 10 of the inner shell 3 and the inlet opening 6 of the outer shell 2 is arranged to be radially offset from the axial center axis of the inner shell 3, so as to obtain a spiral gas flow.
[0050] The basic shape of the cross section of the main wall portion 7 of the outer shell 2 is preferably equal to the basic shape of the cross section of the main wall portion 13 of the inner shell 3. A circumferential gap 15 is formed between the main wall portion 7 of the outer shell 2 and the main wall portion 13 of the inner shell 3, wherein the width of the gap 15 in the radial direction adjacent to the upper edge 12 is equal to or greater than 0.5 mm and equal to or less than 3 mm. The width of the gap 15 may be different in the circumferential direction and / or in the axial direction.
[0051] According to various embodiments, the lower liquid outlet opening 11 of the inner housing 3 is connected to the liquid outlet opening 4 of the outer housing 2 via an intermediate volume / chamber. In other embodiments / alternatives, the liquid outlet opening 11 of the inner housing 3 is connected to the outside of the outer housing 2 via a conduit separate from the liquid outlet opening 4 of the outer housing 2.
[0052] According to the present invention, the inner surface of the top portion 9 of the outer shell 2 and the upper edge 12 of the inner shell 3 are positioned adjacent to each other and together determine the upper liquid outlet opening 17 of the inner shell 3. The upper liquid outlet opening 17 of the inner shell 3 is the opening of the circumferential gap 15. The distance between the inner surface of the top portion 9 of the outer shell 2 and the upper edge 12 of the inner shell 3 is equal to or greater than 0.5 mm and equal to or less than 3 mm, preferably equal to or less than 2 mm. The width of the upper liquid outlet opening 17 of the inner shell 3 in the radial direction may be different in the circumferential direction, but is preferably constant. The upper liquid outlet opening 17 of the inner shell 3 is connected to the liquid outlet opening 4 of the outer shell 2 through the intermediate volume (i.e. through the circumferential gap 15).
[0053] According to various embodiments, the inner surface of the top portion 9 of the outer housing 2 comprises an annular ridge 16 which protrudes downwardly relative to adjacent portions of said inner surface of the top portion 9 of the outer housing 2. The radially inner side of the annular ridge 16 is preferably arranged adjacent to the gas outlet opening 5 of the outer housing 2.
[0054] The annular ridge 16 of the top portion 9 of the outer shell 2 and the upper edge 12 of the inner shell 3 are positioned adjacent to each other and together determine an upper liquid outlet opening 17 of the inner shell 3. The upper liquid outlet opening 17 of the inner shell 3 is the opening of the circumferential gap 15. The distance between the annular ridge 16 of the outer shell 2 and the upper edge 12 of the inner shell 3 is equal to or greater than 0.5 mm and equal to or less than 3 mm, preferably equal to or less than 2 mm. The width of the upper liquid outlet opening 17 of the inner shell 3 in the radial direction may vary in the circumferential direction, but is preferably constant. The upper liquid outlet opening 17 of the inner shell 3 is connected to the liquid outlet opening 4 of the outer shell 2 through the intermediate volume (i.e. through the circumferential gap 15).
[0055] The main wall portion 13 of the inner shell 3 and the upper liquid outlet opening 17 are configured so that the liquid follows the gas flow upward along the inner surface of the inner shell 3, and the liquid will then enter the upper liquid outlet opening 17 and will prioritize / block most of the gas from entering the upper liquid outlet opening 17. Most of the gas will leave the inner shell 3 and enter the gas outlet opening 5 of the outer shell 2. The gas outlet opening 5 of the outer shell 2 is located radially inward of the upper edge of the inner shell. When an annular ridge is present, the gas outlet opening 5 of the outer shell is located radially inward of the annular ridge 16 of the outer shell 2. Some gas will follow the liquid through the circumferential gap 15 and then re-enter the inner shell 3 through the lower liquid outlet opening 11 of the inner shell 3. There is a local lower pressure at the center of the inner shell 3, which causes the gas in the intermediate volume between the outer shell 2 and the inner shell 3 to be sucked into the inner shell 3 through the lower liquid outlet opening 11 of the inner shell 3.
[0056] Thus, the configuration of the annular ridge 16 of the outer housing 2 together with the upper edge 12 of the inner housing 3 ensures that liquid flowing upwardly along the inner surface of the inner housing 3 does not re-enter the pressurized air flow leaving the inner housing 3 .
[0057] According to various embodiments, the annular ridge 16 lies in a radial / horizontal plane in which the upper edge 12 of the inner casing 3 lies.
[0058] According to various embodiments, the upper edge 12 of the inner shell 3 is located radially outside the apex of the annular ridge 16 of the outer shell 2. Thus, the separation effect of the liquid flow entering the upper liquid outlet opening 17 of the inner shell 3 and the gas flow entering the gas outlet opening 5 of the outer shell 2 is enhanced. Alternatively, the edge 12 can be located opposite the apex of the annular ridge 16 and likewise have a clear separation of the liquid flow and the gas flow. The cross-sectional area of the gas outlet opening 5 of the outer shell 2 is larger than the cross-sectional area of the lower liquid outlet opening 11 of the inner shell 3 so as to direct the gas flow upward in the separator 1.
[0059] According to various embodiments, the upper edge 12 of the inner shell 3 is located radially outside the annular ridge 16 of the outer shell 2. Therefore, liquid flowing / running upward along the inner surface of the inner shell 3 does not re-enter the gas flow leaving the separator 1. According to various embodiments, the upper edge 12 of the inner shell 3 is located at the same height as the apex of the annular ridge 16 of the outer shell 2 or above the height of the apex.
[0060] Also refer to Figure 4 and 5 , Figure 4 and 5 Various embodiments / alternatives are disclosed which may be combined with the above-described embodiments / alternatives.
[0061] The main wall portion 13 of the inner housing 3 does not have a constant cross-sectional area in the axial direction, but has a cross-sectional area that increases in the upward direction from the bottom wall portion 14 toward the upper edge 12. The upper portion (i.e., adjacent to the upper edge 12) of the main wall portion 13 of the inner housing 3 may have a constant cross-sectional area. The cross-sectional area of the main wall portion 7 of the outer housing 2 may be constant in the axial direction, or may increase in the upward direction from the bottom wall portion 8 to the top portion 9.
[0062] Possible variations of the invention
[0063] The invention is not limited to the embodiments described above and shown in the drawings, which are intended for illustration and example purposes only. This patent application will cover all variations and modifications of the preferred embodiments described herein, and the invention is therefore determined by the wording of the appended claims, so that the device can be modified in all conceivable ways within the framework of the appended claims.
[0064] It should also be noted that all information about terms such as above, below, upper, lower, etc. should be interpreted / read with the device oriented according to the drawings, wherein the drawings are oriented so that the reference numerals can be read in the correct manner. Therefore, these terms only represent relative relationships in the illustrated embodiments, which can change when the device according to the invention is provided with another structure / design.
[0065] It should also be noted that even if it is not explicitly stated that features from a certain embodiment can be combined with features from another embodiment, the combination should be considered obvious when the combination is feasible.
Claims
1. A centrifugal separator (1) for separating liquid from wet gas, wherein: The centrifugal separator (1) comprises: - an outer casing (2), said outer casing comprising: - a liquid outlet opening (4) which is located at the bottom of the outer housing (2), - a gas outlet opening (5) located at the top of the outer casing (2), and Therein, the centrifugal separator (1) comprises an inlet opening (6) for wet gas, said inlet opening being located between a liquid outlet opening (4) and a gas outlet opening (5) of the outer casing (2), Characterized in that the centrifugal separator (1) further comprises: - an annular inner casing (3) located inside the outer casing (2) so as to form an intermediate volume delimited by the inner casing (3) and the outer casing (2), wherein the inlet opening (6) of the centrifugal separator (1) extends to the inner casing, the inner casing (3) comprising: - an inlet hole (10) of the inlet opening (6), - a lower liquid outlet opening (11) located at the bottom of the inner housing (3), and - an annular upper edge (12), - wherein the inner surface of the top portion (9) of the outer shell (2) and the upper edge (12) of the inner shell (3) are located adjacent to each other and together define an upper liquid outlet opening (17) of the inner shell (3), - the gas outlet opening (5) of the outer casing (2) is located radially inside the upper edge (12) of the inner casing (3), and The upper liquid outlet opening (17) of the inner housing (3) is connected to the liquid outlet opening (4) of the outer housing (2) via an intermediate volume.
2. The centrifugal separator (1) according to claim 1, wherein: The inner surface of the top portion (9) of the outer shell (2) includes an annular ridge (16) which protrudes downwardly relative to an adjacent portion of the inner surface of the top portion of the outer shell (2), the annular ridge (16) of the outer shell (2) and the upper edge (12) of the inner shell (3) being positioned adjacent to each other and together defining an upper liquid outlet opening (17) of the inner shell (3).
3. The centrifugal separator (1) according to claim 1 or 2, wherein: The transverse center axis of the joint of the inlet hole (10) of the inner casing (3) and the inlet opening (6) of the centrifugal separator (1) is arranged radially offset from the axial center axis of the inner casing (3).
4. A centrifugal separator (1) according to any one of the preceding claims, wherein: The lower liquid outlet opening (11) of the inner housing (3) is connected to the liquid outlet opening (4) of the outer housing (2) via an intermediate volume.
5. A centrifugal separator (1) according to any one of the preceding claims, wherein: The inner housing (3) has an annular main wall portion (13) including the inlet opening (10) and a tapered bottom wall portion (14) including the lower liquid outlet opening (11).
6. The centrifugal separator (1) according to claim 5, wherein: The inlet opening (10) of the inner housing (3) is located at the lower end of the main wall portion (13).
7. A centrifugal separator (1) according to claim 5 or 6, wherein: The main wall portion (13) of the inner housing (3) has a constant cross-sectional area in the axial direction or has an increasing cross-sectional area in the upward direction.
8. A centrifugal separator (1) according to any one of claims 5 to 7, wherein: The main wall portion (13) of the inner housing (3) has a circular cross section or an elliptical cross section when viewed from above.
9. A centrifugal separator (1) according to any one of the preceding claims, wherein: The outer housing (2) has a main wall portion (7) comprising an inlet opening (6) of the centrifugal separator (1) and a tapered bottom wall portion (8) comprising a liquid outlet opening (4).
10. A centrifugal separator (1) according to any one of the preceding claims, wherein: The outer housing (2) and the inner housing (3) are coaxial.
11. The centrifugal separator (1) according to claim 2, wherein: The upper edge (12) of the inner shell (3) is located radially outward of the apex of the annular ridge (16) of the outer shell (2).
12. The centrifugal separator (1) according to claim 2, wherein: The upper edge (12) of the inner shell (3) is located radially outside the annular ridge (16) of the outer shell (2).
13. A centrifugal separator (1) according to claim 11 or 12, wherein: The upper edge (12) of the inner shell (3) is located at the same height as or above the apex of the annular ridge (16) of the outer shell (2).
14. A centrifugal separator (1) according to any one of the preceding claims, wherein: The cross-sectional area of the gas outlet opening (5) of the outer shell (2) is larger than the cross-sectional area of the lower liquid outlet opening (11) of the inner shell (3).