DC CYCLONE SEPARATION

Description

[0001] The invention relates to a direct current cyclone separator for separating particles from a dispersion containing the particles and a fluid. A suspension is particularly suitable as the dispersion. The invention further relates to the use of a direct current cyclone separator.

[0002] To separate particles from a dispersion containing the particles and a fluid, such as a gas or liquid, filters are used, for example, in which the dispersion is passed through a membrane. The particles are deposited on the membrane, which must therefore be replaced after a certain period to prevent clogging. An alternative to this are cyclone separators, also known as centrifugal separators. Cyclone separators are designed either as counterflow cyclones, also known as tangential cyclones, or as coflow cyclones, also known as axial separators.

[0003] In dispersion flows, particles are subject to the influence of bulk forces and fluid forces. Bulk forces in a swirling flow include, for example, centrifugal forces and the acceleration due to gravity. Fluid forces in a swirling flow include, for example, aerodynamic forces caused by a radial velocity gradient. Here, a buoyancy force acts on the particles due to a gradient of dynamic pressure. The particles are thus drawn towards the faster flow components.

[0004] In a countercurrent cyclone separator, the dispersion is directed into a vessel with a rounded side wall, such as a barrel or a cone, whereby the

[0005] The introduction of the dispersion occurs tangentially. The axis of the container is therefore essentially vertical and perpendicular to the original direction of flow of the dispersion, and consequently perpendicular to the direction in which the dispersion enters the container. Therefore, the dispersion is forced into a circular or spiral shape, which is determined by the container wall. Due to the typically higher weight of the particles, they are forced radially outwards and slowed down by the wall. As a result, the particles collect at the bottom of the container. The fluid is usually discharged from an outlet located vertically above the bottom, typically above the point where the dispersion enters the container. Because of the vertical introduction of the dispersion into the container, the space requirement is increased, and retrofitting existing systems with such a countercurrent cyclone separator is therefore usually not possible.Furthermore, the direction in which the fluid is discharged from the counterflow cyclone separator does not correspond to the direction in which the dispersion is discharged into the counterflow cyclone separator, which is why further deflections of the dispersion are necessary. In addition, a comparatively high pressure drop occurs for the fluid and / or the particle separation process.

[0006] An alternative to this are direct current cyclone separators. In these, the dispersion is set into a rotational motion around an axis along the direction of its movement. This motion is usually generated by guide vanes arranged within a pipe section of the direct current cyclone separator, or by a tangentially introduced secondary current. This imparts a velocity in the tangential direction to the dispersion, with the maximum velocity of the dispersion, i.e., its absolute value, being located essentially midway between a pipe wall and the center of the pipe. Thus, here too, the particles are moved radially outwards, while the fluid is moved essentially in the center of the direct current cyclone separator.However, since the maximum speed is not located at the edge of the pipe section, the force acting on particles in a radial direction is reduced the further they move away from the area of ​​maximum speed, which is why only a few particles accumulate in the edge area.

[0007] The rotation of the dispersion leads to the formation of a Hamel-Oseen vortex, which essentially corresponds to a rigid body vortex in the core region and, radially outwards, to a potential vortex extending towards the pipe wall. Depending on this vortex structure, a region of maximum absolute velocity is formed, which can be considered a sink with respect to the fluid forces, and towards which the particles are moved.

[0008] Due to its design, the direct-flow cyclone separator can be retrofitted into existing systems. Manufacturing costs for such a direct-flow cyclone separator are also reduced. Furthermore, only a comparatively small pressure drop occurs, as it is not necessary to deflect the dispersion perpendicular to the direction of flow. However, compared to the counter-current cyclone separator, the efficiency of the direct-flow cyclone separator and the separation efficiency between the particles and the fluid are reduced. Particularly in the direct-flow hydrocyclone configuration, the separation rate is further reduced due to the essentially identical density of the particles and the fluid.

[0009] EP 1 512 453 A1 discloses a device for separating solid particles and liquids from a gas stream, comprising a hollow cylindrical housing with square recesses for attaching an inlet guide apparatus.

[0010] The inlet guide apparatus has an increasing angle of inclination. The inlet guide apparatus features guide elements that project inwards from the inner wall of the hollow cylindrical housing.

[0011] The invention is based on the objective of providing a particularly suitable direct current cyclone separator, advantageously with increased efficiency.

[0012] With regard to the direct current cyclone separator, this problem is solved according to the invention by the features of claim 1. Advantageous further developments and embodiments are the subject of the respective dependent claims.

[0013] The direct current cyclone separator is used for separating particles from a dispersion containing the particles and a fluid. In particular, the dispersion consists of the particles and the fluid. The density of the particles and the density of the fluid are, for example, essentially equal. Specifically, the ratio of the densities is equal to 1 or at least between 0.95 and 1.05, or between 0.99 and 1.01, or between 0.995 and 1.005. The particles have, for example, a size of 1 nm to 1 µm, or preferably larger than 1 µm. Particularly preferably, the particles have a size between 0.1 mm and 1 mm or larger. The particles consist, for example, of a single substance or of different substances or elements. In particular, the particles are heterogeneous. For example, sand forms at least part of the particles. The fluid is, for example, a gas or, more preferably, a liquid. In particular, the fluid is incompressible and a liquid.In other words, a dispersion is a suspension. The fluid is, for example, water, which is taken from a flowing body of water or the sea. Specifically, the fluid is intended for use as cooling water in an industrial plant or as process water in mining. Alternatively, the fluid is intended for use in a desalination plant, and the dispersion is seawater containing particles, especially sand.

[0014] The DC cyclone separator is an axial separator. In other words, the DC cyclone separator is a centrifugal separator designed to be axially unidirectional. The dispersion is guided through the DC cyclone separator in one direction, and this direction is not changed, particularly for the purpose of separation. Ideally, the direction of flow is constant. In other words, the direction in which the dispersion, or at least the fluid, is guided is not altered.

[0015] The direct current cyclone separator comprises a hollow cylindrical pipe section designed to guide the dispersion in the flow direction. During operation, the dispersion is guided through this hollow cylindrical pipe section. The flow direction is advantageously parallel to the axis of the hollow cylindrical pipe section, at least in some sections. The pipe section has an inner wall along which the dispersion is guided during operation. Preferably, the hollow cylindrical pipe section has a substantially circular cross-section. Adequately, the hollow cylindrical pipe section is free of other components of the direct current cyclone separator, allowing the dispersion to flow through it relatively freely. In other words, there is no other component within the inner wall, and the inner wall thus forms a cavity.

[0016] The inner wall of the pipe section has an internal thread. In other words, the inner wall has a groove that runs helically along the guiding direction. In particular, the groove forms a helix, preferably a curve that winds around the surface of a cylinder with a certain gradient, the cylinder being provided, in particular, by the inner wall. In other words, the internal thread winds around the axis of the hollow cylindrical pipe section. Specifically, the inner wall has the internal thread along its entire length in the guiding direction. The length of the pipe section is, for example, equal to the diameter of the pipe section, greater than the diameter of the pipe section, greater than or equal to twice the diameter of the pipe section, or greater than or equal to three times the diameter of the pipe section.Preferably, the length of the pipe section is greater than or equal to 10 times, 20 times, 50 times, 100 times or 150 times the diameter of the pipe section.

[0017] The internal thread serves to generate swirl in the dispersion, so that after passing through the internal thread, it exhibits a velocity component tangential, i.e., perpendicular to the guiding direction. Thus, the internal thread is the swirl generator. In other words, the internal thread imparts a rotational motion to the dispersion in addition to its translational motion along the guiding direction, with the rotational motion being perpendicular to the guiding direction. The tangential velocity component is applied by the internal thread to the layers of dispersion moving along the inner wall, and due to viscosity or similar factors, this component is transferred to the further, inner regions of the dispersion. Consequently, the dispersion exhibits a non-constant velocity profile.

[0018] In summary, the outer regions of the dispersion, i.e., those located relatively close to the inner wall, particularly in the area of ​​the inwardly projecting extension, exhibit the highest velocity due to the internal thread. This velocity corresponds to the velocity predominant due to the dispersion's movement along the guiding direction, plus the velocity imparted by the internal thread. The portion of the dispersion located primarily in the center exhibits only the velocity component in the guiding direction. Due to the viscosity of the dispersion, the velocity increases essentially linearly from the center of the pipe section to the inner wall, so that the rotational motion of the dispersion essentially corresponds to that of a solid.

[0019] As a result, the particles are moved radially outwards towards the inner wall of the pipe section relatively efficiently due to centrifugal force, particularly in conjunction with the fluid force. The force acting on the particles increases radially with decreasing distance from the inner wall. Thus, the particles are moved more strongly outwards the further they are located, leading to a relatively sharp separation between the particles and the fluid in the dispersion. The particles themselves move primarily along the helical path defined by the pitch of the internal thread. No moving parts are required to separate the particles from the dispersion, which reduces construction costs and the potential for defects. Furthermore, efficiency is increased. The particles are removed from the fluid by means of a suitable separation chamber, which is expediently located downstream of the pipe section.By means of the direct current cyclone separator, an efficiency, i.e. the ratio of the fluid discharged from the direct current cyclone separator to the volume of the dispersion introduced into the direct current cyclone separator, of up to 80% is achieved, whereby a particle separation (particle separation efficiency) of up to 95% is achieved during operation.

[0020] The internal thread has a thread formed by a groove. In other words, the thread corresponds to the groove, and the thread is helically shaped along the guiding direction, with the inner wall thus grooved to form the thread. Preferably, the internal thread has a number of such threads. This improves swirl generation in the dispersion. Advantageously, the number of threads is between two and 100, between four and 20, and, for example, equal to 12, which leads to comparatively effective swirl generation, particularly reducing the formation of vortices. Furthermore, with such a number of threads, manufacturing costs are comparatively low. The threads are provided, for example, by grooves which, for instance, have a substantially rectangular cross-section.Particularly preferably, the passages are rounded, and the cross-section of each passage is suitably handle-shaped and / or auricle-shaped. Thus, the cross-section of each passage is at least partially spiral, in particular logarithmic spiral, and / or curved. Consequently, the hollow cylindrical tube section essentially has a cross-section that is gear- or saw-blade-shaped. In particular, the cross-section is designed in the manner of a freewheel. Due to the rounded shapes, the formation of undesirable vortices, which would otherwise reduce efficiency, is further reduced.

[0021] The helix angle of the internal thread increases in the guiding direction. For example, the helix angle starts at 0° and increases continuously, thus further preventing the formation of vortices. As a result, the rotational speed of the dispersion about an axis along the guiding direction increases continuously, further increasing efficiency. In particular, the helix angle of the internal thread corresponds to the helix angle of any threads present, and the helix angle of the threads is, in particular, the same, at least at the same position in the guiding direction. The helix angle is, in particular, the angle that the internal thread, especially the thread, forms with the guiding direction. Preferably, the helix angle is between 15° and 60° and increases, for example, between 15° and 60°, suitably continuously or exponentially.Consequently, after passing through the pipe section, the dispersion exhibits essentially the same velocity component in the guiding direction as in the tangential direction in the region of the inner wall. Advantageously, the angle of inclination is chosen such that a subcritical swirl is formed, the swirl being determined, in particular, by the ratio of the velocity component in the tangential direction to the velocity component in the guiding direction, and corresponding, for example, to this ratio. As a result, the turbulence intensity is reduced. Specifically, a subcritical swirl (reduced turbulence intensity) forms up to a critical swirl degree, and a supercritical swirl (increased turbulence intensity) forms above the critical swirl degree. The subcritical swirl is particularly advantageous for particle separation.The degree of swirl results in particular from the ratio of the tangential to the axial momentum flux.

[0022] Preferably, a second, hollow cylindrical pipe section is connected downstream of the first pipe section. The two pipe sections are advantageously arranged coaxially. Preferably, the second pipe section adjoins the first directly, and the first pipe section preferably transitions directly into the second pipe section. In particular, the second pipe section is integrally formed with the second pipe section and is thus integral, particularly monolithic, with it. The second pipe section preferably has a substantially circular cross-section. Advantageously, the second pipe section has the same inner diameter on the side facing the first pipe section as the first, which prevents turbulence of the dispersion or fluid during the transition from the first pipe section to the second pipe section.The second pipe section therefore also has an inner wall, and the dispersion, or at least the fluid and the particles separated from it, are also guided through the second pipe section in the direction of operation, from the pipe section.

[0023] The inner wall of the second pipe section, for example, has an internal thread at least partially, and in particular completely, wherein the internal thread of the first pipe section advantageously transitions directly into the internal thread of the second pipe section. In other words, the thread(s) of the internal thread(s) are aligned. Preferably, the helix angle of the internal thread of the first pipe section at the transition is equal to the helix angle of the internal thread of the second pipe section. Alternatively or in combination with this, the inner wall of the second pipe section is smooth, at least partially, and in particular completely. A baffle is arranged in the second pipe section. This baffle is positioned, in particular, centrally within the second pipe section and preferably on the axis of the second pipe section.

[0024] Advantageously, the baffle body is rotationally symmetrical, or more preferably rotationally symmetrical, with respect to the axis of the second pipe section. The baffle body is, in particular, flow-optimized. For example, the baffle body is designed in a teardrop shape, with the thickened end directed, in particular, towards the pipe section. In this way, the fluid resistance of the baffle body is reduced, and turbulence is avoided. Guide vanes extending radially outwards are attached to the baffle body, in particular by integral part thereof. In other words, the path of the guide vanes has at least one component in the radial direction. The guide vanes extend between the baffle body and the inner wall of the second pipe section, i.e., at least partially radially and outwards with respect to the baffle body. For example, the guide vanes extend at least partially tangentially and are preferably spirally curved.The guide vanes are spaced away from the inner wall of the second pipe section.

[0025] Due to the distance of the guide vanes from the inner wall, the radially outer portion of the dispersion is influenced relatively little by the guide vanes. Because of this distance, the rotational motion of the dispersion is maintained, so that it continues to exhibit rotation even after passing the baffle and the guide vanes. The guide vanes primarily ensure the maintenance of the swirl. The distance of the guide vanes from the outer wall has the particular effect of maintaining the maximum absolute velocity of the swirling flow at the outer wall. Due to the baffle, the dispersion is forced radially outwards from the center of the second pipe section, while the rotational motion of the dispersion caused by the pipe section is maintained.As a result, the particles are forced radially outwards and, due to the rotational movement, accelerated further towards the inner wall of the second pipe section. The increased centrifugal force and / or the fluid force act on the radially outward-moving particles, causing particles still present in the fluid after passing through the pipe section to be deposited towards the inner wall of the second pipe section. After passing the baffle, the fluid is essentially only moved back into the center of the second pipe section, so that only the outer areas of the dispersion still contain the particles. The inner areas of the dispersion, on the other hand, essentially only contain the fluid that moved inwards after passing the baffle. Thus, the baffle and the guide vanes improve efficiency.

[0026] The guide vanes are advantageously inclined with respect to the guiding direction. In particular, the guide vanes are inclined with respect to the axis of the hollow cylindrical second pipe section and are thus arranged at an angle to it. The guide vanes suitably form an external thread connected to the baffle body. Due to the inclination, the dispersion is also set into rotational motion during operation by means of the guide vanes, or at least the rotational motion of the dispersion is maintained.

[0027] The inclination angle of the guide vanes is suitably equal to the helix angle of the internal thread. In other words, the guide vanes have the same helix angle as the internal thread. If the helix angle of the internal thread is variable, the helix / inclination angle of the guide vanes is, in particular, equal to the helix angle of the internal thread at the transition from the first pipe section to the second pipe section, provided the second pipe section does not have an internal thread. If the second pipe section also has an internal thread, the helix angle of the guide vanes is equal to the helix angle of the internal thread of the second pipe section. If the helix angle of the internal thread of the second pipe section is variable, the helix angle of the guide vanes is also variable and suitably changes according to the helix angle of the internal thread.The helix angle of the guide vanes is advantageously equal to the helix angle of the internal thread at the same position in the axial direction and / or in the guiding direction. Due to the inclination of the guide vanes, the rotational movement generated by the internal thread is thus amplified or at least maintained. Consequently, the guide vanes also serve to generate or at least maintain swirl.

[0028] The length of the guide vanes in the guiding direction is preferably reduced with decreasing distance to the inner wall. In other words, the length of the guide vanes over which the dispersion flows decreases towards the inner wall. As a result, the dispersion essentially retains the original velocity at the pipe wall that prevails when exiting the pipe section, and the dispersion continues to exhibit essentially a rotational motion corresponding to that of a solid. In this way, the separation of particles from the fluid is further improved. Alternatively, the cross-section of the guide vanes has a trailing edge. In particular, the guide vane cross-section is helical.

[0029] Preferably, the baffle body and / or the guide vanes are made of a plastic material. For example, the baffle body and the guide vanes are formed in one piece (monolithic). For instance, between 3 or 20 guide vanes, and suitably 4 or 8 guide vanes, are attached to the baffle body. This results in a comparatively low flow resistance, while still ensuring efficient maintenance or introduction of rotational motion into the dispersion.

[0030] Preferably, the second pipe section is widened on the side opposite the first. For example, the inner diameter of the second pipe section increases continuously, or at least from a certain point onward, the inner diameter increases continuously. Alternatively, a step or similar feature may be present. Due to the widening, particles are moved further away from the center of the second pipe section, thus preventing them from flowing back into the center of the second pipe section after passing through the baffle. Furthermore, this simplifies particle separation. In particular, the cross-sectional area of ​​the gap surrounding the flow body increases steadily / exponentially due to the widening. This creates flow conditions that prevent backflow / backflow of the particles.Thus, particles contained in the secondary volume flow no longer enter the primary volume flow.

[0031] For example, a hollow cylindrical third pipe section is fluidically connected upstream of the pipe section, particularly directly. In other words, the third pipe section transitions seamlessly into the pipe section, and the pipe sections are advantageously integrally formed with one another, particularly as a single piece, for example, monolithically. Advantageously, the axes of the hollow cylindrical pipe sections are parallel to each other, preferably identical. Particularly preferably, the third pipe section is arranged coaxially with the pipe section, and / or the pipe section has the same inner diameter as the third pipe section. The cross-section of the third pipe section is, for example, circular. A further baffle is arranged in the third pipe section, particularly centrally.The dam body is, for example, arranged centrally on the axis of the hollow cylindrical third pipe section and is suitably designed to be rotationally or rotationally symmetrical with respect to this axis.

[0032] Guide vanes extending radially outwards are arranged on the second baffle body. In other words, the additional guide vanes extend at least partially radially outwards from the second baffle body. The guide vanes are attached to an inner wall of the third pipe section. Thus, essentially every component of the dispersion is influenced in its movement by the guide vanes, with the dispersion being forced radially outwards due to the baffle body. In other words, the additional guide vanes serve to guide the dispersion. For example, there are 20 additional guide vanes between two and 10 additional guide vanes. Alternatively, the baffle body is omitted, and the additional guide vanes are integrally formed with each other. Due to the additional guide vanes, a pre-swirl is provided, which is why the pipe section, in particular, can be shortened.In this case, the pipe section serves to "homogenize / calm" the swirl flow. Specifically, the length of the pipe section must be at least ten times its (inner) diameter.

[0033] The additional guide vanes are preferably inclined, at least partially, with respect to the guiding direction. In other words, the additional guide vanes have an angle of inclination with the guiding direction or at least with the axis of the third pipe section. Here, the angle of inclination is, for example, constant. However, it is particularly preferred that the angle of inclination is not constant and the guide vanes are thus curved. Due to the inclination of the guide vanes, a swirling motion is introduced into the dispersion even before it enters the pipe section, i.e., a rotational motion about the axis of the third pipe section. In other words, during operation, the dispersion enters the pipe section already partially rotating.The internal thread of the pipe section reduces any turbulence within the dispersion and homogenizes the motion pattern, particularly the velocity profile of the dispersion, so that the dispersion exiting the pipe section essentially exhibits the velocity profile of a rotating solid. In other words, the velocity component in the tangential direction increases with increasing radial distance from the central axis of the pipe section, particularly linearly. If the second pipe section is present, the helix angle of the internal thread on the side facing the third pipe section is, in particular, different from 0° and corresponds, in particular, to the inclination angle of the guide vanes with respect to the guiding direction on the side facing the pipe section. As a result, the swirl flow is, in particular, calmed.

[0034] A separation chamber is preferably connected fluidically downstream of the pipe section. If a second pipe section is present, the separation chamber is connected fluidically downstream of the second pipe section, particularly directly. If a second pipe section is not present, the separation device is connected, for example, directly downstream of the pipe section. The separation chamber itself has a separating tube, which is arranged, in particular, coaxially to the pipe section, preferably coaxially to the second pipe section, if present. The separating tube (immersion tube) itself has, for example, a substantially round cross-section perpendicular to the direction of flow. Advantageously, the separating tube is oriented substantially parallel to the direction of flow. The inner diameter of the separating tube is smaller than the inner diameter of the pipe section. The separating tube is surrounded circumferentially by a collection chamber.Due to the movement of the particles towards the inner wall of the pipe section, the particles are moved into the collection chamber (secondary flow rate), while the fluid enters the separation pipe (primary flow rate). Thus, the separation chamber provides a fluid cleaned of particles as well as the particles themselves, which contain only comparatively small traces of the fluid.

[0035] The collection chamber conveniently surrounds the separating tube, which, for example, has a relatively thin wall. This allows the purity of the fluid or the purity of the separated particles to be selected by choosing the inner diameter of the separating tube. For example, the separating tube is at least partially closed on the side opposite the pipe section by means of a cone or the like, with a circumferential slot formed, in particular, between the edge of the separating tube and the cone. During operation, the fluid exits through the slot. Preferably, the tip of the cone projects into the separating tube, and the cone is expediently arranged coaxially with the separating tube. The cone serves, in particular, as a pressure equalizer and / or for regulating the pressure / velocity ratios at the inlet of the separating tube. Alternatively, the separating tube is, for example, provided with a connection for a line.For example, the inner diameter of the separating tube is widened on the side opposite the pipe section. For instance, the inner diameter increases from the beginning of the separating tube towards the pipe section in the guiding direction. As a result, the fluid velocity is reduced during operation.

[0036] A direct-flow cyclone separator with a hollow cylindrical pipe section for guiding a dispersion in a specific direction, wherein an inner wall of the pipe section has an internal thread, is used for separating particles from the dispersion, which comprises the particles and an incompressible fluid, such as a liquid. In other words, the dispersion is a suspension. Specifically, the dispersion consists of the particles and the incompressible fluid, the fluid being, for example, a mixture of different liquids. The fluid is, for example, water or comprises water. The particles are, for example, homogeneous or, more preferably, heterogeneous and suitably have a particle size greater than 1 µm, greater than 0.1 mm, or greater than 1 mm. The direct-flow cyclone separator is suitably used in an industrial plant, particularly for the supply of cooling water.Alternatively, the direct current cyclone separator is used in mining, particularly for the supply of process water. Alternatively, the direct current cyclone separator is used for pre-treatment in desalination plants, especially for desalinating seawater.

[0037] The further training and advantages described in connection with the direct current cyclone separator can also be applied analogously to its use and vice versa.

[0038] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. The drawing shows: Fig. 1 schematically shows a direct current cyclone separator with a pipe section whose inner wall has an internal thread, and with a second pipe section in which a baffle body with guide vanes attached to it and extending radially outwards is arranged. Fig. 2 shows a cross-section of the pipe section, Fig. 3 shows a perspective view of the baffle body with the guide vanes attached to it and extending radially outwards, Fig. 4 schematically shows a further development of the direct current cyclone separator, and Fig. 5 shows a cross-section of a further development of the second pipe section and a baffle body with guide vanes attached to it.

[0039] Corresponding parts are marked with the same reference symbols in all figures.

[0040] In Fig. 1 A schematically simplified cross-sectional view of a direct current cyclone separator 4 along a longitudinal axis 2 shows a direct current cyclone separator 4. The direct current cyclone separator 4 is used to filter a dispersion 6, which consists of an incompressible fluid 8 in the form of water and particles 10 in the form of sand, thus separating the particles 10 from the dispersion 6 so that the incompressible fluid 8 is essentially pure. The dispersion 6 is therefore a suspension. The direct current cyclone separator 4 is installed upstream of a seawater desalination plant, and the dispersion 6 is taken from the sea, so the fluid 8 is seawater. The particles 10 present in the seawater would damage the desalination plant or at least reduce its efficiency. Therefore, it is necessary to remove the particles 10, i.e., the sand, as well as other solid components present in the seawater.

[0041] The direct current cyclone separator 4 has a hollow cylindrical pipe section 12 and a second, also hollow cylindrical, pipe section 14 connected downstream of it. The second pipe section 14 is integrally formed with the pipe section 12 and arranged coaxially with it. The inner diameter of the pipe section 12 is constant and equal to the inner diameter of the second pipe section 14 on the side facing the pipe section 12. On the side opposite the pipe section 12, the second pipe section 14 is flared, so that its inner diameter increases.

[0042] In terms of fluid mechanics, a separation chamber 16 is connected downstream of the second pipe section 14, and thus also downstream of the pipe section 12. The separation chamber 16 has a collection chamber 18 with a guide tube 20, which is integrally formed on the second pipe section 14 on the side opposite pipe section 12. The second pipe section 14 widens at a continuous distance from pipe section 12, and the guide tube 20 also widens at a further increasing distance from pipe section 12. The inner diameter of the guide tube 20 on the side facing the second pipe section 14 is equal to the inner diameter of the second pipe section 14. The guide tube 20 is also arranged coaxially with the second pipe section 14, i.e., with the longitudinal axis 2, so that there is a relatively flat transition between them.

[0043] Within the guide tube 20, a separating tube 22 is arranged coaxially with it, and thus also coaxially with the pipe section 12 and the second pipe section 14. The inner diameter of the separating tube 22 is smaller on the sides of the pipe section 12 and the second pipe section 14 than the inner diameter of the pipe section 12, and thus also smaller than the inner diameter of the second pipe section 14. The inner diameter of the separating tube 22 widens with increasing distance from the pipe section 12, the length of which the separating tube 22 is widened corresponding to the length of the guide tube 20. In other words, the separating tube 22 is widened in the region within which it is located inside the guide tube 20. Thus, a circumferential gap 24 is formed between the guide tube 20 and the separating tube 22, the cross-sectional area of ​​which increases continuously / exponentially away from the pipe section 12.The length of the separating tube 22 is greater than the length of the guide tube 20, and a partition 26 for limiting the collection chamber 18 is attached to the guide tube 20 at a distance from it, in particular by integral part thereof. Thus, the separating tube 22 is at least partially surrounded by the collection chamber 18. A conically shaped pressure element 28 projects into the separating tube 22 from the side opposite the tube section 12, with its apex also being coaxial with the longitudinal axis 2. A circumferential slot 30 is formed between the pressure element 28 and the separating tube 22.

[0044] The hollow cylindrical pipe section 12 has an inner wall 32 that forms the radial boundary of the pipe section 32 inwards. The area within the inner wall 32 is free of other components of the DC cyclone separator 4, so that during operation, the dispersion 6 can flow freely through the pipe section 12 in a direction 34 that is parallel to the longitudinal axis 2 and directed from the pipe section 12 towards the separation chamber 16. The inner wall 32 has an internal thread 36 with twelve threads 38. The length of the pipe section 12 in the direction 34 is, for example, 6.5 m.

[0045] In Fig. 2 A cross-section of the pipe section 12 perpendicular to the longitudinal direction 2 is shown. The threads 38 are rounded and shaped like handles or ears, resulting in a circular saw blade-shaped cross-section of the pipe section 12. A helix angle 40 is formed between each of the threads 38 and the guide direction 34, with all helix angles 40 of the threads 38 being the same for every cross-section perpendicular to the longitudinal direction 2. In other words, the threads 38 run at a constant tangential distance and consequently parallel to each other. The helix angles 40 increase in the guide direction 34. Thus, the threads 38 have an angle of 15° in the guide direction at the beginning of the pipe section 12. At the transition of the pipe section to the second pipe section 14, the internal thread 36, and therefore all threads 38, have a helix angle of 45°. The increase in the helix angle 40 is linear or exponential.Consequently, the course of the channels 38 is helical around the longitudinal axis 2, with the distance between the individual helical turns (helix) decreasing in the guiding direction 34 due to the increasing angle of inclination. In other words, it is a compressed helix (helix).

[0046] The second pipe section 14 also has an inner wall 41 with an internal thread 42, which also has twelve threads. The threads 38 of the thread 36 of the pipe section 12 transition directly into the threads of the internal thread 42 of the second pipe section 14 and are aligned with them. The helix angle 40 of the thread 42 of the second pipe section 14 is constant and is 45°. Within the second pipe section 14, there is a Fig. 3 The baffle body 44, shown in perspective, is arranged in a teardrop shape and made of a plastic. The thickened end faces the pipe section 12, and the tapered end points towards the separation chamber 16. Alternatively, the baffle body 44 has a lens-shaped contour that tapers to a point towards the separation chamber 16. In other words, the baffle body 44 has a rotationally symmetrical shape with respect to its upper wing contour. The rotationally symmetric baffle body 44 is arranged centrally within the second pipe section 14 and is therefore rotationally symmetrical with respect to the longitudinal axis 2. The maximum radial extent of the baffle body 44, i.e., perpendicular to the longitudinal axis 2, is essentially equal to half the diameter of the pipe section 12. The maximum extent depends in particular on the flow velocity and the particles to be separated.

[0047] Eight radially outward-extending guide vanes 46 are attached to the dam body 44, of which only four are shown. The guide vanes 46 are spaced apart from the inner wall 41 of the second pipe section 14 and inclined with respect to the guide direction 34, so that they wrap around the dam body 44 and thus form an external thread. The angle of inclination of the guide vanes 46 with respect to the guide direction 34 is equal to the angle of inclination 40 of the internal thread 36 at the transition to the second thread 42 and is equal to the angle of inclination of the internal thread 42 of the second pipe section 41, and therefore equal to 45°. The length of the guide vanes 46, i.e., their extension in the guide direction 34, decreases with increasing distance from the longitudinal axis 2. Thus, the guide vanes 46 are also essentially teardrop-shaped in a side view. The guide vanes 46 run radially in the cross-section (pipe cross-section) (lying directly on the radius).Alternatively, the cross-section of the guide vanes 46 has a trailing edge. That is, the guide vane cross-section follows a spiral contour.

[0048] During operation, the dispersion 6 is introduced into the pipe section 12 through an inlet opening 48 located on the side opposite the second pipe section 14, in the guiding direction 34. The dispersion 6 essentially exhibits only a velocity component in the guiding direction 34. Due to the internal thread 36, the dispersion is set into a rotational motion about the longitudinal axis 2 in the region of the inner wall 32. This velocity component is also transmitted to regions of the dispersion 6 that are spaced away from the inner wall 32 due to the viscosity of the dispersion 6. Consequently, the velocity component of the dispersion 6 perpendicular to the guiding direction 34 is greater the further the dispersion 6 is located from the inner wall 32.The magnitude of the velocity is proportional to the distance from the longitudinal axis 2, which is why the dispersion 6, in addition to its translational motion in the longitudinal direction 34, also exhibits a rotational motion directed about the longitudinal axis 2. In other words, the axis of rotation of the dispersion is the same as the longitudinal axis 2. Consequently, the dispersion 6 behaves like a solid, in which, during rotational motion, the tangential velocity component increases linearly with the distance from the axis of rotation. Due to the increasing angle of inclination 40, the rotational velocity of the dispersion 6 increases with increasing penetration into the pipe section 12. Due to the centrifugal force (volume force) caused by the rotation and the buoyant force (fluid force directed towards the inner wall 32, caused by the velocity gradient), the particles 10 are moved radially outwards.

[0049] Following its passage through pipe section 12, the dispersion 10 encounters the baffle 44, causing the entire dispersion to move radially outwards. Due to the internal thread 42 of the second pipe section 14 and the guide vanes 46, the rotational movement of the dispersion 6 is maintained. After passing the radially widest point of the baffle 44, the rotational movement causes only the fluid 8 to move again in the direction of the longitudinal axis 2, while the particles 10 remain radially outwards. The particles 10 are therefore located further away from the longitudinal axis 2 than the opening of the separating tube 22, which is why the particles 10 enter the gap 24 and thus the collection chamber 18. There, they encounter the partition 26 and are thus prevented from moving further in the guiding direction 34.Fluid 8, on the other hand, is located inwards towards the longitudinal axis 2 with respect to the inner wall 41 of the second pipe section 14 and enters the separating pipe 22. There, it encounters the pressure chamber 18 and is discharged from the DC cyclone separator 4 via the slot 30. By selecting the inner diameter of the separating pipe 22 on the side of the second pipe section 14, it is possible to adjust the purity of the fluid 8 or the particles 10.

[0050] In Fig. 4 Figure 4 shows a modification of the direct current cyclone separator 4. In this version, a hollow cylindrical third pipe section 50 is fluidically connected upstream of the inlet opening 48. No other modifications are present, so the pipe section 12, the second pipe section 14, the separation chamber 16, the baffle 44, and the guide vanes 46 remain unchanged. Alternatively, the length of the pipe section 12 is shortened. The third pipe section 14 has the same inner diameter as the pipe section 12 and is arranged concentrically to it. Furthermore, the third pipe section 50 is integrally formed with the pipe section 12 and is therefore monolithic. Within the third pipe section 50, another baffle 52 is arranged, which is cylindrical or flow-optimized and is arranged concentrically to the longitudinal axis 2.On the side opposite pipe section 12, the further impoundment body 52 is dome-shaped. In summary, the impoundment body 52 is located centrally in the third pipe section 50, with the further impoundment body 52 being spaced away from an inner wall 54 of the third pipe section.

[0051] Additional guide vanes 56 extending radially outwards are attached to the further baffle body 52. ​​There are ten additional guide vanes 56. These additional guide vanes 56 extend radially and are attached to and integrally formed with the further baffle body 52 and the inner wall 54 of the third pipe section 50. Furthermore, the additional guide vanes 56 are inclined and curved in sections with respect to the guiding direction 34, i.e., with respect to the longitudinal axis 2. Consequently, during operation, the dispersion 6 is introduced into the third pipe section 50 on the side opposite pipe section 12 and is set into rotation with respect to the longitudinal axis 2 by means of the additional guide vanes 56. In this process, the dispersion 6 is forced past the baffle body 52, the inner wall 54 of the third pipe section 50, and the additional guide vanes 56.Due to the curvature of the additional guide vanes 56, the rotational speed of the dispersion 6 increases with increasing passage in the guiding direction 34. Alternatively, the additional dam body 52 is omitted, and the additional guide vanes 56 are connected to each other in the middle of the third pipe section 50.

[0052] Due to friction of the dispersion 6 against the guide vanes 56 of the inner wall 54 of the third pipe section 50, as well as against any baffle 50 present, the radially outer parts of the dispersion exhibit a reduced velocity. In particular, the velocity profile of the dispersion 6 after passing the baffle 52 and the further guide vanes 56 is such that the maximum velocity of the dispersion is located essentially midway between the inner wall 54 of the third pipe section 50 and the longitudinal axis 2. The dispersion 6, thus set in rotation, is guided into the pipe section 12. Here, the velocity profile is modified by means of the internal thread 36 of the pipe section 12, such that the (absolute) velocity of the dispersion 6 increases with increasing distance from the longitudinal axis 2. Consequently, upon exiting the pipe section 12, the dispersion 6 exhibits a velocity profile similar to that of a rotating solid.In other words, the rotational speed of the dispersion 6 increases linearly with increasing distance from the longitudinal axis 2. Here too, due to the rotational movement introduced into the dispersion 6 by means of the additional guide vanes 56 and the thread 36, the particles 10 are separated from the incompressible fluid 8. Therefore, after passing through the second pipe section 14, the particles 10 are essentially completely discharged through the gap 24 and the fluid 8 through the slot 30 from the DC cyclone separator.

[0053] The swirl of the dispersion 6 is generated by means of the pipe section 12, which is designed in the manner of a swirl tube. In other words, the dispersion 6 is set into a rotational motion. Thus, the dispersion 6 is set into rotational motion due to a pressure impulse input resulting from the threads 38, which have a helix angle 40° with respect to the longitudinal axis 2. Alternatively, the threads 38 are not rounded, but, for example, have a square shape. At a minimum, however, the pipe section 12 has the internal thread 32, which comprises several threads 38. The thread pitch, i.e., the helix angle 40° of the internal thread 36, increases continuously, for example, from 5° to 45°.

[0054] Provided the additional guide vanes 56 are present, the internal thread 36 homogenizes the rotational motion of the dispersion 6, thereby reducing the length of the pipe section 12, i.e., its extension in the guiding direction 34. The thread 36 introduces a swirl structure into the dispersion 6, corresponding to a pure rigid body rotation (solid rotation). In other words, the tangential velocity profile increases linearly radially outwards, particularly from the pipe's central axis, i.e., from the longitudinal axis 2. Consequently, the maximum absolute velocity of the dispersion 6 is located essentially at the inner wall 32 of the pipe section 12 and at the inner wall 41 of the second pipe section 14. As a result, the particles 10 are subjected to a centrifugal force acting point-symmetrically outwards from the pipe's central axis, i.e., the longitudinal axis 2.In other words, the particles 10 are moved radially outwards, whereas the fluid 8 remains in the middle of the pipe sections 12,14 due to the reduced density and the forces acting upon it.

[0055] The particles 10 are also carried along by faster flow components of the dispersion 6. Since the comparatively fast flow components are offset towards the inner wall 32 of pipe section 12 and towards the inner wall 41 of the second pipe section 14, the particles 10 are moved radially outwards with relative efficiency. To improve the movement of the particles 10 from the region of the pipe's central axis, i.e., from the region of the longitudinal axis 2, towards the inner wall 41 of the second pipe section 14, the baffle 44 is arranged within the second pipe section 14 and fluidically upstream of the separation chamber 16. The baffle 44 is designed with optimized flow characteristics. In this way, separation zones and the associated turbulence in the downstream area are avoided.

[0056] The guide vanes 56 have the same pitch as the internal thread 36 and / or the internal thread 42 of the second pipe section 14, if present. The flow length of the guide vanes 46 decreases towards the inner wall 41 of the second pipe section 14 and is advantageously comparatively small at the inner wall 41. Consequently, the swirling flow of the dispersion 6 maintains its maximum velocity in the region of the inner wall 41 of the second pipe section 14. In other words, the dispersion 6 exhibits its highest velocity in the tangential direction and / or in the guiding direction 34 in the region of the inner wall 41 of the second pipe section 14. Thus, the rigid body rotation structure of the dispersion 6 is maintained even after and during passage through the second pipe section 14.Therefore, due to the geometry of the baffle 44, the particles 10 contained in the dispersion 6 are forced outwards into an area of ​​comparatively fast flow, particularly a comparatively high velocity in the tangential direction, and are carried along by this flow. Consequently, after passing the baffle 46, the particles 10 do not return to the center of the pipe, and thus do not reach the longitudinal axis 2.

[0057] The separation of particles 10 takes place via the separation chamber 14. The geometric design of the separating tube 22, the guide tube 10, and the gap 24 formed between them is crucial for the separation efficiency, i.e., the percentage of separated particles 10, as well as for the efficiency, i.e., the ratio of the fluid 8 discharged from the co-current cyclone separator 4 to the volume of the dispersion 6 introduced into the co-current cyclone separator. The internal thread 36 optimizes the fluid-mechanical rotation of the dispersion 6. The baffle 44, in conjunction with the internal thread 36, ensures optimized separation of the particles 10.

[0058] The direct current cyclone separator 4 serves to separate particles 10 from a compressible or incompressible fluid 8. Here, the dispersion 6 is set into rotation by means of the pipe section 12, which is designed as a swirl tube. For more efficient rotation generation, the inner wall 32 has an internal thread 36 with multiple threads 38, which ideally have an increasing helix angle 40 in the guiding direction 34, corresponding to the flow direction of the dispersion 6. The swirl structure of the dispersion 6 generated in this way resembles a pure rigid body rotation (solid body rotation) with a radially outward linearly increasing velocity profile in the tangential direction. After passing through the pipe section 12, the rotating dispersion 6 is guided around a baffle 44, which is positioned in the middle of the second pipe section 14 and upstream of the separation chamber 16.Due to the baffle 44, the proportion of particles 10 located in the area around the central axis of the second pipe section 14, i.e., in the area around the longitudinal axis 2, is reduced, and the particles 10 are deflected towards the inner wall 41 of the second pipe section 14. The baffle 44 and the guide vanes 46 are designed for optimized flow and shaped such that the swirling flow continues to have its maximum velocity at the inner wall 41 of the second pipe section 14, which is why the particles 10 located in the dispersion 6 are forced outwards. These are separated from the fluid 8 by means of the separation chamber 16.

[0059] In other words, the invention relates to a direct current cyclone separator 4, also referred to as a unidirectional particle cyclone separator or axial particle cyclone separator (centrifugal separator). This separator is particularly designed and suitable for separating particles 10 from a dispersion 6, wherein the dispersion 6 comprises the incompressible fluid 8 and preferably consists of the incompressible fluid 8 and the particles 10. The direct current cyclone separator 4 has a pipe section 12 with an internal thread 36. In other words, the pipe section 12 has an inner pipe wall that is at least partially thread-like, with the internal thread 36 serving to generate swirl, i.e., to impart rotational motion to the dispersion 6 in addition to translational motion along the longitudinal direction 34. The thread pitch, i.e. the helix angle 40 of the internal thread 36, increases along the guiding direction 34, i.e. along the flow direction.

[0060] Preferably, the direct current cyclone separator 4 has a second pipe section 14, in the center of which the flow-optimized baffle body 44 is arranged, to which the helically shaped guide vanes 46 are attached. The pitch of the helical guide vanes 46 corresponds to the largest thread pitch, i.e., the largest helix angle 40 of the internal thread 36. Furthermore, the flow-through length of the guide vanes 46 decreases towards the inner wall 41 of the second pipe section 14.

[0061] Furthermore, the second pipe section 14 is widened on the side facing away from pipe section 12. In other words, the inner diameter is increased. Additionally, the direct current cyclone separator 4 preferably has the separation chamber 16 with the separating tube 22, which is inserted into the guide tube 20 in the counterflow direction, i.e., opposite to the guide direction 34. At the downstream end, the pressure element 28 is inserted into the separating tube 22, with the slot 30 formed between them. The downstream end of the separating tube 22 is the end of the separating tube 22 that faces away from pipe section 12. The separating tube 22 is arranged coaxially with pipe section 12, the second pipe section 14, and the guide tube 20, and the inner and outer diameters of the separating tube 22 are reduced and thus narrowed in the counterflow direction, i.e., on the side of the second pipe section 14.

[0062] In Fig. 5A further development of the second pipe section 14 is shown in a cross-section. The guide vanes 46 are essentially modified. Eight guide vanes 46 are rotationally symmetrically connected to the reservoir body 44, of which only one is shown, and which are spirally shaped.

[0063] Thus, the guide vanes 46 also exhibit a tangential orientation. Furthermore, the guide vanes 46 have a trail with respect to the swirl.

[0064] The invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived by a person skilled in the art without departing from the subject matter of the invention as defined by the claims. In particular, all individual features described in connection with the individual embodiments can also be combined with one another in other ways without departing from the subject matter of the invention. Reference symbol list

[0065] 2 Longitudinal axis 4 DC cyclone separator 6 Dispersion 8 Fluid 10 Particles 12 Pipe section 14 Second pipe section 16 Separation chamber 18 Collection chamber 20 Guide pipe 22 Separation pipe 24 Gap 26 Partition wall 28 Back pressure body 30 Slot 32 Inner wall 34 Direction of flow 36 Internal thread 38 Thread 40 Angle of inclination 41 Inner wall of the second pipe section 42 Internal thread of the second pipe section 44 Back pressure body 46 Guide vane 48 Inlet opening 50 Third pipe section 52 Additional back pressure body 54 Inner wall of the third pipe section 56 Additional guide vane

Claims

1. Uniflow cyclone separator (4) for separating particles (10) from a dispersion (6), in particular suspension, comprising the particles (10) and a fluid (8), comprising a hollow-cylindrical tube section (12) for guiding the dispersion (6) in a guiding direction (34), characterised in that an inner wall (32) of the tube section (12) comprises a notch, by means of which a helix is formed, which winds around the inner wall (32) with a slope, wherein a slope angle (40) of the helix increases in the guiding direction (34).

2. Uniflow cyclone separator (4) according to claim 1, in which the tube section (12) comprises a number of notches, by means of which a helix is formed in each case, the slope angle (40) of which increases in the guiding direction (34), wherein the distance from individual corresponding helical windings decreases as a result of the increase in the slope angle (40) in the guiding direction (34).

3. Uniflow cyclone separator (4) according to claim 2, characterised in that the number is between 2 and 100, in particular between 4 and 20.

4. Uniflow cyclone separator (4) according to one of the preceding claims, in which the length of the tube section (12) is greater than the diameter of the tube section (12), greater than twice the diameter of the tube section (12), greater than three times the tube section (12), or greater than 10 times, 20 times, 50 times, 100 times or 150 times the diameter of the tube section (12).

5. Uniflow cyclone separator (4) according to one of the preceding claims, characterised in that the slope angle (40) is between 15° and 60°.

6. Uniflow cyclone separator (4) according to one of the preceding claims, characterised in that a hollow-cylindrical second tube section (14) is connected fluid technically downstream of the tube section (12), wherein a damming body (44) having guide blades (46) connected thereto and extending radially outwards is arranged in the second tube section (14), and wherein the guide blades (46) are spaced apart from an inner wall (41) of the second tube section (14).

7. Uniflow cyclone separator (4) according to claim 6, characterised in that the guide blades (46) are inclined with respect to the guiding direction (34), and comprise the same slope angle (40) as the notch.

8. Uniflow cyclone separator (4) according to claim 6 or 7, characterised in that the length of the guide blades (46) in the guiding direction (34) is reduced as the distance from the inner wall (41) decreases.

9. Uniflow cyclone separator (4) according to one of claims 6 to 8, characterised in that the second tube section (14) is widened on the side opposite the tube section (12).

10. Uniflow cyclone separator (4) according to one of the preceding claims, characterised in that a hollow-cylindrical third tube section (50) is connected fluid technically upstream of the tube section (12), wherein a further damming body (52) having further guide blades (56) connected thereto and extending radially outwards is arranged in the third tube section (56), and wherein the further guide blades (56) are connected to an inner wall (54) of the third tube section (50).

11. Uniflow cyclone separator (4) according to claim 10, characterised in that the further guide blades (56) are inclined at least in sections with respect to the guiding direction (34).

12. Uniflow cyclone separator (4) according to one of the preceding claims, characterised in that a separating chamber (16) is connected fluid technically downstream of the tube section (12) and comprises a separating tube (22) which is arranged coaxially with the tube section (12) and whose inner diameter is smaller than the inner diameter of the tube section (12), and which is circumferentially surrounded by a collecting chamber (18).