Cooling device for particulate materials

Abstract

The present invention relates to an apparatus (1) for cooling particulate material or particles, in particular granules of polymeric material, comprising an outer vessel (2) having an outer shell surface (3), in particular frustoconical, and an inner vessel (4) arranged at least partially inside the outer vessel (2) and having an inner shell surface (5), in particular frustoconical, wherein an intermediate space (6) is formed between the outer shell surface (3) and the inner shell surface (5), an inlet fitting (7) for introducing a gas flow and particles into the intermediate space (6) is provided in an inlet start region (11) of the apparatus (1), an outlet opening (15) for the particles is provided in an outlet end region (12) of the apparatus (1) opposite the inlet fitting (7), and the inlet fitting (7) is arranged and / or designed so that the gas flow and particles can be introduced into the intermediate space (6) substantially tangentially.

Description

Technical Field

[0001] The present invention relates to an apparatus for cooling particulate materials, particularly granulates of polymeric materials, as claimed in claim 1.

Background Art

[0002] The production of granulates is carried out, for example, by plasticizing a polymeric material in an extruder. The strand-shaped polymer melt extruded from the perforated plate is cut into small-sized particles by a rotating blade. These granulates are transported away from the fluid flow while being cooled and solidified in a gas stream or a water stream, with at least the core region remaining in a molten state.

[0003] Subsequently, for example, further cooling of the particles is carried out in a further downstream cooling unit. For example, a cylindrical cooling container for moving the granulates and cooling them during the movement is known from the prior art.

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is an object of the present invention to create a cooling unit that can keep the residence time of the granulates as long as possible and keep the change in the residence time of individual particles narrow, and in which the particles are kept in a separated state.

Means for Solving the Problems

[0005] The object is achieved by means of an apparatus according to the features of claim 1. According to the invention, the apparatus comprises an outer container having an outer shell surface, in particular in the shape of a frustum of a cone, and an inner container having an inner shell surface, in particular in the shape of a frustum of a cone, which is at least partially arranged inside the outer container, and an intermediate space is formed between the outer shell surface and the inner shell surface. In the inlet-side starting region of the apparatus, inlet equipment for introducing a gas flow and particles or granulates into the intermediate space is provided, and an outlet opening for the particles is provided in the outlet-side end region of the apparatus opposite the inlet equipment. The inlet equipment is arranged and / or designed such that the gas flow and the particles can be introduced into the intermediate space essentially in a tangential direction.

[0006] The gas flow or the particles are introduced specifically in a tangential direction and, as a result, move through the intermediate space between the outer shell surface and the inner shell surface, thereby extending the path that the particles must pass through when passing through the apparatus, resulting in an increase in the residence time. At the same time, the change in the residence time of the particles is kept narrow. Also, by guiding the air flow in this way, the gas is kept in a sufficient laminar flow and no turbulent flow occurs. For this reason, the particles are kept within a narrow velocity range, and uncontrolled collisions that cause deceleration of the particles are reduced.

[0007] Furthermore, the contact of the particles with the wall is also minimized, preventing deceleration and / or deposition of the particles. Adhesion of the granulate particles to the wall is also avoided. Particularly advantageously, adhesion between the granulate particles is also maximally prevented.

[0008] The particles are transported by a medium passing through the apparatus, in particular a gas. This gas can be any gas or mixture of gases, in particular air is used. By the gas flow transporting the particles, these material particles, granulates, or sausage-like substances, etc. are cooled by the gas flow. They are further solidified if necessary and, if necessary, further chemically react, for example, by thermal effects, cooling, or reactions initiated or induced by the gas. It is also possible to use a volatile medium, such as water, etc.

[0009] The device according to the present invention can be used for all materials capable of forming granules from strands. Such materials include polymers, dough, ceramic masses, rubber, thermoplastic polyurethanes, and silicones. The granulating material may be reinforced with fibers and / or may be partially crosslinked. They can be based on polyester, polyolefin, and further polyamide. In particular, according to the device of the present invention, it is possible to transport all at least partially plastifiable and preferably extrudable materials that can be softened or melted, converted into particles, or solidified, and in particular, it is also possible to cool them during transportation.

[0010] Preferred further developments of the above device can be seen from the features described in the dependent claims.

[0011] For example, it is preferably configured that the outer shell surface and / or the inner shell surface are arranged substantially rotationally symmetric with respect to the central longitudinal axis.

[0012] The above device is usually installed vertically, but can also be installed horizontally, that is, horizontally, or can be installed at an inclined position according to convenience.

[0013] To achieve a preferred gas flow, the outer shell surface and / or the inner shell surface are inclined by a conical angle β with respect to the central longitudinal axis, and the conical angle is in the range of 1° ≤ β ≤ 15°, particularly in the range of 3° ≤ β ≤ 10°, preferably in the range of 3° ≤ β ≤ 6°. This helps to keep the air flow fast enough so that the particles remain separated in the intermediate space for a particularly long time, and in particular, it also enables particularly heavy particles to remain in the cooling funnel for a correspondingly long time.

[0014] If the outer shell surface and the inner shell surface are separated from each other over the entire circumference without contact, a flow without disturbance can be achieved.

[0015] A favorable residence time can also be obtained when the width of the intermediate space between the outer shell surface and the inner shell surface is in the range of 20 mm ≤ a ≤ 200 mm, particularly in the range of 50 mm ≤ a ≤ 100 mm, preferably in the range of 60 mm ≤ a ≤ 80 mm. Thereby, the particles remain in the intermediate space for a long time and remain in a separated state. If the interval is too large, the circumferential air flow will be too small, resulting in a decrease in the residence time of the particles. If the gap is too narrow, the air velocity and the particle density will increase, and as a result, the residence time will be short, but the probability of the particles colliding or hitting each other will also increase.

[0016] In connection with this, it is advantageous to take into account the size or diameter of the granulated product or particles when selecting the width a of the intermediate space 6. The advantageous width a is in the range of 4 to 40 times the average diameter of the particles.

[0017] According to a preferred embodiment, the outer shell surface and the inner shell surface are , in other words, so as to be separated from each other at a uniform distance and run along, aligned so as to be parallel to each other.

[0018] Alternatively, the width of the intermediate space between the outer shell surface and the inner shell surface may decrease particularly uniformly in the direction of the end region on the outlet side. The fact that the intermediate space tapers in this way is particularly preferred for smaller particles. This is because the accelerating effect of the gas flow due to the narrower intermediate space is used to maintain the separation effect.

[0019] Or, the width of the intermediate space between the outer shell surface and the inner shell surface may increase particularly uniformly in the direction of the end region on the outlet side. Conversely, an increase in the height of the intermediate space is also preferred for larger particles. This is because the braking effect due to the collision with the wall is reduced, making it easier to maintain the separation.

[0020] The inner container or the inner shell surface is shorter or has a lower height than the outer container or the outer shell surface. In this regard, it has been found preferable that the length or height of the outer container or the outer shell surface is greater than the length or height of the inner container or the inner shell surface. It is particularly advantageous if the ratio hi:ha is within the range of 0.1 to 1, particularly within the range of 0.3 to 0.85, preferably within the range of 0.50 to 0.75.

[0021] To properly attach or connect the inlet equipment to the device, it is preferable that the outer shell surface and the inner shell surface are flush at the inlet side starting region.

[0022] Furthermore, it is preferable that the diameter of the outer shell surface at the inlet side starting region is larger than the diameter at the outlet side ending region, or that the outer container is tapered in the direction of the outlet side ending region.

[0023] Similarly, this is also preferable for the inner container. That is, it is preferable that the diameter of the inner shell surface at the inlet side starting region is larger than the outlet side diameter at the outlet side ending region, or that the inner container is tapered in the direction of the outlet side ending region.

[0024] Therefore, if the outer shell surface and the inner shell surface are tapered in the direction of the outlet side ending region, it is possible to achieve a more uniform flow velocity, a preferable residence time, and a preferable residence time variation.

[0025] To effectively separate the particles from the gas flow, it is advantageous if the outer shell surface extends further or is longer than the inner shell surface in the direction of the outlet-side end region. As a result, a separation region where no intermediate space is formed beyond the tip of the inner container exists in this part near the outlet of the device. This separation region is defined only by the outer container or the outer shell surface. Therefore, the particles also continue to move spirally along the outer shell surface until they reach the outlet. On the other hand, since the gas flow is discharged through the inner container in the opposite direction, i.e., the inlet direction, at the end of the intermediate space or in the separation region, the particles are separated from the gas flow.

[0026] To separate the particles from the gas flow, the inner shell surface is preferably open or gas-permeable at the end on the inlet-side start region side, so that the inner shell surface near the inlet-side start region can discharge gas from this opening. For this opening, a gas-permeable cover surface can be provided, for example, by a grid.

[0027] The separation of the particles is promoted by making the outer shell surface longer compared to the inner shell surface. In this regard, the opening defined by the diameter of the outer shell surface in the outlet-side end region, or the region defined by the diameter of the outlet opening, is smaller than the opening defined by the diameter of the inner shell surface in the outlet-side end region so as to generate sufficient flow resistance to separate the particles from the air with respect to the air, which is particularly preferable for effectively separating the particles from the gas.

[0028] Therefore, the outlet opening defined by the outlet-side opening can be made smaller until it hardly allows gas or air to escape from this opening and a large resistance is brought about such that the gas cannot flow out unless it takes the path through the inner container. However, this requires increasing the overall height and may be impossible to achieve for design reasons in some cases.

[0029] A preferred configuration in this regard is that, particularly in the case of vertical installation, a tapered, particularly frustum-shaped, exit nozzle through which particles pass and exit the apparatus is arranged at the exit-side end region of the outer shell surface, i.e., at the exit-side opening. This exit nozzle tapers more steeply in the height direction because the wall has a steeper angle. As a result, good separation of the gas is achieved even with a low overall height. Therefore, the exit-side opening of the outer shell surface becomes smaller. This is because the area of the exit opening is much smaller. In this regard, it is particularly preferable for the area of this exit opening to be 20% or less, preferably 10% or less, of the area of the opening defined by the diameter in the exit-side end region of the outer shell surface for better separation of the particles from the gas flow.

[0030] To achieve a tangential flow in the intermediate space, it is preferable for the inlet equipment to have an inlet flow path and, in particular, an inlet nozzle arranged upstream thereof that can supply the gas flow and the particles to be cooled. The inlet flow path is curved for space saving and has the same width as the intermediate space. The inlet flow path extends parallel to the periphery of the outer shell surface and the inner shell surface, and thus basically opens tangentially into the intermediate space.

[0031] Therefore, the gas or particle flow thus directed not only moves tangentially towards the inner or outer periphery of the intermediate space but is also properly introduced at a low entry angle. In this regard, it is preferable for the inlet flow path to open into the intermediate space at an angle α within the range of 0 < α ≦ 10° with respect to a plane perpendicular to the longitudinal axis. It is particularly preferable for the inlet flow path to be inclined at this angle constantly over its entire longitudinal range for the flow conditions. By forming such a directional orientation, it is possible to cause the movement of particles in a specific direction even when a large amount of medium is required.

[0032] Therefore, this entry angle α is understood to be the basic direction of the flow of the gas and the particles or particulate material. This entry angle is then maintained over at least the initial portion across the further path of the particles in the intermediate space.

[0033] In this way, the particles or gas flow into the intermediate space in a tangential and slightly outlet direction. As a result, for example, as shown in FIG. 6, preferred movement patterns for residence time, residence time variation, and separation are obtained. Thus, the particles move from the inlet-side starting region along a spiral path to the outlet-side ending region, and the diameters of these spiral paths gradually decrease.

[0034] Usually, the amount or velocity of the gas flow is adjusted according to the required conditions and particle size. In this regard, it may be preferable that an additional amount of gas is introduced. In this regard, additional gas suction holes are preferably formed in the outer shell surface and / or the inner shell surface and are arranged and / or designed such that additional gas rather than particles can be introduced into the intermediate space, particularly basically in a tangential direction. The flow of the additional gas assists the main gas flow via the inlet equipment, thereby cooling the particles more and affecting the residence time. That is, for example, it is also possible to introduce a low-temperature gas into the funnel and cool it further accordingly. It is also possible to introduce a reactive gas here to initiate a specific reaction.

[0035] Further advantages and embodiments of the present invention will become apparent from the specification and the accompanying drawings.

[0036] The present invention is schematically illustrated below with reference to particularly advantageous non-limiting examples in the embodiments shown in the drawings and will be described illustratively with reference to the drawings.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 3a

Figure 4

Figure 5

Figure 6a

Figure 6b

Embodiments for Carrying Out the Invention

[0038] Figures 1 to 4 are views of the apparatus 1 according to the present invention from respective viewpoints. In the present embodiment, the apparatus 1 is installed vertically, more specifically, within a support frame. At the uppermost region of the apparatus 1, inlet equipment 7 for introducing a flow of gas or particles is arranged. The upper part of this apparatus 1 is defined as an inlet-side starting region 11. The part of the apparatus 1 opposite to the inlet equipment 7 is defined as an outlet-side ending region 12. This is also the location where the outlet opening 15 through which particles exit the apparatus 1 is located.

[0039] The above-described apparatus 1 includes an outer container 2 and an inner container 4 arranged inside thereof. The outer container 2 has a frustum-shaped outer shell surface 3, and the inner container 4 has a frustum-shaped inner shell surface 5. The inner container 4 is arranged inside the outer container 2 such that an intermediate space 6 is formed between the outer shell surface 3 and the inner shell surface 5. The width a of the intermediate space between the outer shell surface 3 and the inner shell surface 5 is approximately 70 mm in the illustrated example.

[0040] The outer shell surface 3 and the inner shell surface 5 are continuously spaced apart from each other and do not contact at any location. Therefore, there is no barrier in the intermediate space 6, and a frustum-shaped annular space is formed in which the gas flow and particles circulate spirally.

[0041] The outer shell surface 3 and the inner shell surface 5 are inclined by a conical angle β with respect to the central longitudinal axis 10. In this example as one embodiment, the conical angle β is about 5°.

[0042] In this example as one embodiment, the outer shell surface 3 and the inner shell surface 5 are aligned to be parallel to each other. However, there may be cases where it is preferable to deviate from the parallel alignment, for example, to increase or decrease the gap width.

[0043] It can be seen that the outer shell surface 3 and the inner shell surface 5 are tapered in the direction of the exit-side end region 12, that is, here towards the bottom. Therefore, at the inlet side Start the diameter da1 of the outer shell surface 3 in the inlet-side start region 11 is larger than the diameter da2 of the outer shell surface 3 in the exit-side end region 12, or in this example, larger than the lower opening 18 of the outer shell surface 3.

[0044] Similarly, the diameter di1 of the inner shell surface 5 in the inlet-side start region 11, or in this example, the upper opening 19 of the inner shell surface 5, is larger than the exit-side diameter di2 of the inner shell surface 5 in the exit-side end region 12. The relatively large-diameter upper opening 19 of the inner shell surface 5 in the inlet-side start region 11 is closed by the cover surface 17.

[0045] It can also be seen that the length or height ha of the outer shell surface 3 is larger than the height hi of the inner shell surface 5. In the device 1 according to FIG. 1, the ratio hi:ha is about 0.6.

[0046] This means that at the lower part of the device 1, there is a separation region 16 where no intermediate space 6 is formed beyond the tip of the inner container 4. This separation region 16 is defined only by the outer container 2 or the outer shell surface 3.

[0047] However, the particles continue to move downward along the outer shell surface 3 within the separation region 16. On the other hand, the gas flow is discharged upward through the inner shell surface 5 at the end of the intermediate space 6. Here, the particles are separated from the gas flow. The particles exit from the bottom of the device 1 through the outlet opening 15, and the gas exits from the top of the device 1 through the upper opening 19 of the inner shell surface 5. In the illustrated example, a gas-permeable cover surface 17 is provided at this upper opening 19 by means of a grid.

[0048] By reducing the diameter of the outer shell surface 3, the flow resistance increases. If the opening 18 at the lower end of the outer shell surface 3 is small enough, the flow resistance becomes very large, so that the gas does not exit from this lower opening 18 and exits only through the upper opening 19 of the inner shell surface 5. However, the particles always exit from the bottom, and when this lower opening 18 is small enough, it also functions as the outlet opening 15 at the same time. However, in this case, in most cases, the overall height of the device 1 increases. Therefore, the flow resistance can also be further increased by additional countermeasures. As shown as an example of an embodiment according to FIG. 3a, an additional frustum-shaped outlet nozzle 13 is arranged at the bottom of the outlet-side end region 12 of the outer shell surface 3. The original outlet opening 15 for the actual particles through which the particles finally exit the device 1 is also formed in this outlet nozzle 13. The outlet nozzle 13 is directly connected to the lower opening 18 of the outer shell surface 3, and the cross-sectional area of the outlet opening 15 is considerably smaller than the cross-sectional area of the lower opening 18, and in this case, it is only about 7-8% of the cross-sectional area of the lower opening 18. This additional cross-sectional narrowing further increases the flow resistance, so that the particles are more effectively separated from the gas flow.

[0049] The inlet equipment 7 arranged in the inlet-side start region 11 has, for example, an inlet nozzle 8 that can be connected to a transport line, and through this inlet nozzle 8, still-hot particles or granulates are introduced into the device 1 together with the gas flow.

[0050] The inlet nozzle 8 opens into the inlet flow path 9. This inlet flow path 9 is curved or spirally curved and is parallel to the periphery of the outer shell surface 3 and the inner shell surface 5 , in other words, so as to run along the periphery of the outer shell surface 3 and the inner shell surface 5, and extends basically circularly. The inlet flow path 9 fits exactly at the top or the inlet side of the intermediate space 6. In the illustrated example, with the diameters of the shell surfaces 3 and 5 and at the inclination angle α, the inlet flow path 9 draws an almost complete circle of almost 360° and then opens into the intermediate space 6 in the region approximately below the inlet nozzle 8. Accordingly, the inlet flow path 9 has the same width a as the intermediate space 6. Thus, the flow of gas or particles is introduced tangentially into the intermediate space 6, that is, the flow of particles and gas flows along an almost circular path around the central longitudinal axis 10 in the intermediate space 6. Also, thereby, turbulent flow, tear-off edges, and impact edges are avoided.

[0051] Furthermore, the inlet flow path 9 slopes slightly downward toward the outlet. This has already been shown in FIG. 1, and the inlet flow path 9 enters into the interior of the intermediate space 6 across a surface that slopes constantly downward. As shown in FIG. 2, this entry inclination angle α is defined with respect to the plane 14 perpendicular to the longitudinal axis 10 and is about 5°.

[0052] In this way, the flow of particles or gas is not only introduced tangentially into the intermediate space 6 but is also directed slightly downward. As a result, a movement pattern as shown in FIG. 6 is obtained. Thus, the particles move along a spiral path from the inlet-side starting region 11 to the outlet-side ending region 12, and the diameters of these spiral paths gradually become smaller.

[0053] The following embodiments show a comparison of tests with different cooling devices and their results (FIGS. 5, 6a, and 6b).

[0054] The tests were carried out with the following parameters. · Air volume: 2700 m 3 / h · Amount of granulated material: 85 kg / h · Medium: air · Inlet air temperature: 19 °C · The granulated products were always in a separated state.

[0055] TIFF0007682804000001.tif47121

[0056] “Standard type” (Figure 5): Inflow air: 0.6 kg / s; 20 °C Inflow particles: 100 kg / h D 4 mm; 80 orbits

[0057] “Type 1 (cylindrical)” (left column of Figures 6a and 6b): Inflow air: 0.6 kg / s; 20 °C Inflow particles: 100 kg / h D 4 mm; 50 orbits

[0058] “Type 2 (conical)” (right column of Figures 6a and 6b): Inflow air: 0.6 kg / s; 20 °C Inflow particles: 100 kg / h D 4 mm; 50 orbits

[0059] Tests were conducted using different materials. In particular, the velocity distribution and the change in residence time were investigated. The final temperature of the granulated products was also used for the evaluation.

[0060] The cyclone known from the prior art, designated as the "standard type" (Figure 5), is a cylindrical cyclone with a conical tip and has a tangential air inlet, but does not have an inner container and no other equipment in the internal area. At the upper end, there is an air outlet pipe protruding into the cylinder over a range of approximately one-third. In particular, a simulation of the particle residence time was performed for this cyclone. In Figure 5, it can be clearly seen that the particles enter the lower region of the cyclone very quickly, that is, the residence time of the particles in the cooling silo is not long, and particles are accumulating in the lower region or the region of the outlet funnel. That is, the particle frequency increases, adhesion can occur, and twins or triplets (i.e., those in which two or three granulated products adhere to each other) are formed. Also, this region is heated, and as a result, destructive wall adhesion can also occur.

[0061] Regarding the cylindrical cooling silo with an inner shell of "Type 1 (cylindrical)" according to the present invention (left column of Figures 6a and 6b), it can be clearly seen, especially regarding the particle trajectory (Figure 6b), that the particles are guided more uniformly than in the "standard type" cyclone. Due to the guidance of the air in the inlet region, the air flow velocity increases, but this air flow velocity decreases significantly in the height direction. However, this is not such a problem for small unfilled granulated products with a relatively low specific gravity. This is because the air can continue to rotate the granulated products for a sufficiently long time.

[0062] In the conical cooling silo with an inner shell of "Type 2 (conical)" according to the present invention (right column of Figures 6a and 6b), the air flow can be kept generally constant in the height direction. The diameter of the silo decreases, but this increases the residence time of the granulated products in the cooling silo. Furthermore, since the air flow is fast enough, even particularly heavy granulated products can be kept in the spiral flow, remain sufficiently separated, and can be solidified / cooled accordingly.

Claims

1. An apparatus (1) for cooling particulate material or particles, comprising: an outer container (2) having an outer shell surface (3); and an inner container (4) at least partially disposed inside the outer container (2) and having an inner shell surface (5), wherein an intermediate space (6) is formed between the outer shell surface (3) and the inner shell surface (5), inlet equipment (7) for introducing a gas flow and the particulate material or particles into the intermediate space (6) is provided in an inlet-side starting region (11) of the apparatus (1), an outlet opening (15) for the particulate material or particles is provided in an outlet-side ending region (12) of the apparatus (1) opposite to the inlet equipment (7) for the apparatus (1), in the apparatus (1), the inlet equipment (7) is arranged and / or designed such that the gas flow and the particulate material or particles can be introduced tangentially into the intermediate space (6), the inlet equipment (7) has an inlet flow path (9) and an inlet nozzle (8) capable of supplying the gas and the particulate material or particles, the inlet flow path (9) has a curved design, extends along the periphery of the outer shell surface (3) and the inner shell surface (5), and basically opens tangentially into the intermediate space (6), the apparatus (1), characterized in that the inlet flow path (9) fits exactly to the inlet side of the intermediate space (6).

2. The apparatus according to claim 1, characterized in that the particulate material or particles are granules of a polymer material.

3. The apparatus according to claim 1, characterized in that the outer shell surface (3) has a frustoconical shape.

4. The apparatus according to claim 1, characterized in that the inner shell surface (5) has a frustoconical shape.

5. The apparatus according to claim 1, characterized in that the inlet nozzle (8) is arranged upstream of the inlet flow path (9).

6. The apparatus according to any one of claims 1 to 5, characterized in that the outer shell surface (3) and / or the inner shell surface (5) are arranged rotationally symmetrically around a central longitudinal axis (10).

7. The apparatus according to any one of claims 1 to 6, characterized in that the outer shell surface (3) and / or the inner shell surface (5) are inclined by a cone angle (β) with respect to the central longitudinal axis (10), and the cone angle (β) is in the range of 1° ≤ β ≤ 15°.

8. The apparatus according to claim 7, wherein the conical angle (β) is in the range of 3° ≤ β ≤ 10° or in the range of 3° ≤ β ≤ 6°.

9. The apparatus according to any one of claims 1 to 8, wherein the outer shell surface (3) and the inner shell surface (5) are spaced apart from each other over the entire circumference without contacting each other.

10. The apparatus according to any one of claims 1 to 9, wherein the outer shell surface (3) and the inner shell surface (5) are aligned with each other.

11. The apparatus according to any one of claims 1 to 10, wherein the width (a) of the intermediate space (6) between the outer shell surface (3) and the inner shell surface (5) is in the range of 20 mm ≤ a ≤ 200 mm.

12. The apparatus according to claim 11, wherein the width (a) of the intermediate space (6) is in the range of 50 mm ≤ a ≤ 100 mm or in the range of 60 mm ≤ a ≤ 80 mm.

13. The apparatus according to any one of claims 1 to 12, wherein the width (a) of the intermediate space (6) between the outer shell surface (3) and the inner shell surface (5) decreases in the direction of the exit-side end region (12).

14. The apparatus according to claim 13, wherein the width (a) of the intermediate space (6) decreases uniformly in the direction of the exit-side end region (12).

15. The apparatus according to any one of claims 1 to 14, wherein the width (a) of the intermediate space (6) between the outer shell surface (3) and the inner shell surface (5) increases in the direction of the exit-side end region (12).

16. The apparatus according to claim 15, wherein the width (a) of the intermediate space (6) increases uniformly in the direction of the exit-side end region (12).

17. The apparatus according to any one of claims 1 to 16, wherein the length or height (ha) of the outer container (2) or the outer shell surface (3) is greater than the length or height (hi) of the inner container (4) or the inner shell surface (5).

18. The apparatus according to claim 17, wherein the ratio (hi):(ha) of the length or height (hi) of the inner container (4) or the inner shell surface (5) to the length or height (ha) of the outer container (2) or the outer shell surface (3) is in the range of 0.1 to 1, in the range of 0.3 to 0.85, or in the range of 0.50 to 0.

75.

19. The device according to any one of claims 1 to 18, wherein the outer shell surface (3) and the inner shell surface (5) are flush with each other in the inlet-side starting region (11).

20. The device according to any one of claims 1 to 19, wherein the outer shell surface (3) extends further or is longer than the inner shell surface (5) in the direction of the outlet-side end region (12).

21. The device according to any one of claims 1 to 20, wherein the diameter (da1) of the outer shell surface (3) in the inlet-side starting region (11) is larger than the diameter (da2) in the outlet-side end region (12), or the outer container (2) is tapered in the direction of the outlet-side end region (12).

22. The device according to any one of claims 1 to 21, wherein the diameter (di1) of the inner shell surface (5) in the inlet-side starting region (11) is larger than the outlet-side diameter (di2) in the outlet-side end region (12), or the inner shell surface (5) is tapered in the direction of the outlet-side end region (12).

23. The device according to any one of claims 1 to 22, wherein the outer shell surface (3) and the inner shell surface (5) are tapered in the direction of the outlet-side end region (12).

24. The device according to any one of claims 1 to 23, wherein the opening (18) defined by the diameter (da2) of the outer shell surface (3) in the outlet-side end region (12) where the outlet opening (15) is provided, or the region defined by the diameter of the outlet opening (15), is smaller than the opening (19) defined by the diameter (di2) of the inner shell surface (5) in the outlet-side end region (12) so as to generate a flow resistance sufficient to separate particles from the air with respect to the air.

25. An outlet nozzle (13) having a tapered shape through which the particle flow exits the device (1) is arranged at the outlet-side end region (12) of the outer shell surface (3) where the outlet opening (15) is provided, and the area of the outlet opening (15) is 20% or less of the area of the opening (18) defined by the diameter (da2) of the outer shell surface (3) in the outlet-side end region (12). The device according to claim 24.

26. The apparatus according to claim 25, wherein the outlet nozzle (13) has a frustoconical shape.

27. The apparatus according to claim 25, wherein the area of the outlet opening (15) is 10% or less of the area of the opening (18).

28.

3. The apparatus according to any one of claims 1 to 27, wherein the inner shell surface (5) is open or gas-permeable at the end on the side of the inlet-side starting region (11), and a gas-permeable cover surface (17) is provided as required.

29.

5. The apparatus according to any one of claims 1 to 12 and 17 to 28, wherein the inlet flow path (9) has the same width (a) as the intermediate space (6).

30.

7. The apparatus according to any one of claims 1 to 29, wherein the inlet flow path (9) opens into the intermediate space (6) at an angle (a) within the range of 0 < α ≤ 10° with respect to a plane (14) perpendicular to the longitudinal axis (10).

31. The apparatus according to claim 30, wherein the inlet flow path (9) is uniformly inclined at the angle (a) over the entire longitudinal range thereof.

32. The apparatus according to any one of claims 1 to 31, wherein additional gas suction holes are formed in the outer shell surface (3) and / or the inner shell surface (5) and are arranged and / or designed such that the gas can be introduced into the intermediate space (6).

33. The apparatus according to claim 32, wherein the additional gas suction holes are arranged and / or designed such that the gas can be introduced into the intermediate space (6) basically in a tangential direction.

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