Device for cooling freshly extruded filament bundles

Abstract

The invention relates to a device for cooling freshly extruded filament bundles, which has a hollow-cylindrical cooling cylinder through which the filaments are guided and a suction device. The suction device interacts with the cooling cylinder in such a way that a counterflow of cooling air can be generated in the cooling cylinder. In order to achieve a uniform cooling air in the cooling cylinder for cooling the filaments, the cooling cylinder has at least an upper, open longitudinal section and a lower, closed longitudinal section between the filament inlet and the filament outlet, wherein the closed longitudinal section of the cooling cylinder is assigned an air-orienting mechanism at the filament outlet through which the cooling air drawn through the suction device can be directed to the cooling cylinder.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device for cooling freshly extruded filament bundles for producing yarns. BACKGROUND

[0002] It is generally known in synthetic yarn production that a plurality of thin filament strands is extruded from a polymer melt via a plurality of nozzles of a spinning nozzle. Here, the filament strands form a bundle which, upon cooling, is assembled to form a yarn. In order for the filament strands not to bond in the yarn structure, the filament strands must be cooled after extrusion in order to solidify. Filament strand cooling usually takes place by means of a cooling air flow acting on the filament strands. However, all filament strands within the filament bundle ideally necessarily undergo uniform cooling here in order to form an ideally uniform physical property.

[0003] A number of devices for cooling freshly extruded filament strands are known in the prior art, which devices can essentially be divided into groups for generating a cooling air flow. In a first group, which is known, for example, from DE 44 04 258 Al, transversely oriented cooling air flows are directed onto the extruded filament strands. To this end, the blower walls of a blower chamber, which are coupled to the air conditioning air conveyed here and impinge on the filaments transversely, extend in the direction of movement of the filaments. This device, which is also referred to as a cross-flow quench, has a relatively good cooling effect, but its fundamental disadvantage is that the filament bundle is impinged on by the cooling air flow only from one side.

[0004] In order to direct the cooling air flow to the filament bundle from all sides, a second, generally known type of cooling device is known, in which the filament bundle is guided in a cylindrical cooling channel, which has gas-permeable walls and is arranged in a blower chamber. Cooling air directed into the blower chamber then enters the cooling channel from the outside to the inside via the gas-permeable walls of the cooling channel in order to cool the filament strands. Transversely oriented cooling air flows can then be generated over the entire peripheral surface of the filament bundle. This cooling is also referred to as radial quenching in the industry and is disclosed, for example, in US 5 219 582. However, this radial quench has the fundamental disadvantage that the cooling air flow must be discharged in the same direction as the filament strand output via the filament outlet. The bypass flow designed in the direction of movement of the filament strands here has an insulating effect and hinders the shrinkage with the cooling air.

[0005] Cross-flow quenching and radial quenching also generate transversely oriented cooling air flows in regions of the filament strands which are still molten. In this regard, it is necessary for the filament strands to have already solidified sufficiently preliminarily when they are impinged on by the cooling air so as not to encounter any cross-sectional changes, in particular of the outer filament strands, when they are impinged on by the cooling air.

[0006] In order to obtain a cooling air flow which is produced by positive pressure comparatively gently, it is also known from DE 100 48 133 A1 that a cooling channel is connected with its lower end to a suction device, so that a negative pressure is produced in the cooling channel. Here, the cooling air is sucked in in the upper portion of the cooling channel which has a gas-permeable wall. This results in a cooling air flow which is directed essentially in the direction of movement of the filaments. But here too the problem arises that the bypass air flow which is formed on the filament skin as a result of the extraction of the filaments from the spinning nozzle is not sufficiently displaced by the cooling air flow which is directed in the direction of movement of the yarn. Therefore, this device for producing a cooling air flow in the direction of movement of the yarn has not proved to be successful in yarn production.

[0007] However, a device of this type is disclosed by the prior art, namely DE 1 119 456 A1, in which a cooling air flow which is produced counter to the direction of movement of the filaments is used for cooling the filaments. Therefore, it has been attempted for a long time to produce this cooling air flow by means of a suction device which is arranged directly below the spinning nozzle. Such a suction device is usually used for evacuating exhaust air which is produced when extruding the polymer melt, in particular polyamide, and which leads to undesirable contamination.

[0008] In the device for cooling a bundle of filaments disclosed by DE 1 119 456 A1, a cooling cylinder is arranged directly below the spinning nozzle on a suction device. The filament bundle is passed through the cooling cylinder, wherein cooling air enters at the lower end of the cooling cylinder by means of the suction action of the suction device and produces a counterflow in the cooling cylinder. The cooling air then flows counter to the direction of movement of the filament bundle, so that the cooling air flow is oriented counter to the potential bypass flow on the peripheral surface of the filaments. The suction device in the known device acts directly on the inlet side of the cooling cylinder, as a result of which a comparatively high negative pressure must be produced below the spinning nozzle in order to prevail for the counterflow of the cooling air in the cooling cylinder. However, this strong suction action leads to undesirable air turbulence in the air intake at the outlet side of the cooling cylinder, which particularly adversely affects the cooling uniformity of all the filament bundles. SUMMARY

[0009] Although many variants for producing a cooling air flow for cooling the freshly extruded filaments in yarn production are considered, the object is now to improve such a device for cooling a filament bundle with a counter air flow of cooling air, so that the filament bundle can be produced with a high uniformity to produce a synthetic yarn.

[0010] According to the application, this object is achieved in that the cooling cylinder has at least an upper gas-permeable longitudinal portion and a lower closed longitudinal portion between the filament inlet and the filament outlet, and that the closed longitudinal portion of the cooling cylinder is assigned an air orientation mechanism at the filament outlet, by means of which the cooling air which is sucked by the suction device can be guided to the cooling cylinder.

[0011] The application has the following particular advantages: By means of the suction effect of the longitudinal portion on the cooling cylinder circumference and the counterflow of cooling air acting in an unimpeded manner in the closed longitudinal portion of the cooling cylinder to cool the filaments. Furthermore, the cooling air sucked through the filament outlet can advantageously be guided by the directional device in such a way that a uniform counterflow of air is produced in the cooling cylinder also at relatively high negative pressure. Since the directional device is present at the filament outlet of the cooling cylinder, the flow rate of the cooling air can also advantageously be adapted to the respective yarn type.

[0012] In order to allow the cooling air to enter in a virtually turbulence-free manner, the following inventive refinement of the air directional device is preferably implemented, which is formed by an annular inlet nozzle having an inlet cross section towards the environment and an outlet cross section towards the cooling cylinder. Thus, the bunching of the cooling air sucked from the environment can advantageously be achieved.

[0013] For this purpose, the inlet cross section of the inlet nozzle is greater than the outlet cross section of the inlet nozzle, wherein the transition wall of the inlet nozzle between these two cross sections is designed conically and / or is rounded. Thus, a nozzle effect for influencing the air entry into the cooling cylinder can be utilized. The homogenization of the cooling air flow in the cooling cylinder has a particularly positive effect on the Uster value profile of the filament thread.

[0014] But the air entry can also be achieved over a longer inlet distance at the filament inlet. For this purpose, the following inventive refinement of the air directional device is provided, which is formed by a hollow-cylindrical inlet cylinder having a flow cross section towards the cooling cylinder which is substantially the same size, and which is held at the filament outlet in the extension of the cooling cylinder. The cooling air sucked from the environment can be influenced only by the inlet cylinder length. The longer the inlet cylinder configuration, the smaller the amount of air that can be sucked into the cooling cylinder by the suction effect.

[0015] In order to allow the ambient air to be sucked in over the inlet cylinder length, the following inventive refinement of the inlet cylinder is provided, which has a plurality of inlet openings on the cylinder body which are arranged in a dispersed manner on the circumference. The homogenization of the cooling air in the cooling cylinder can also be achieved in this way. In addition, the air quantity can be influenced by means of an adjustable opening cross section of the inlet openings.

[0016] But the air quantity at the inlet cylinder can also be influenced by the following inventive refinement of the air directional device, the inlet cylinder having an adjustable outlet opening at the free end, by means of which the inlet cross section of the inlet cylinder can be changed. Thus, the axial supply of cooling air can be influenced in relation to the radial supply of cooling air at the inlet cylinder.

[0017] Since the cooling air flowing as counterflow has empirically a strong cooling effect on the thread filaments, the following inventive refinement is particularly suitable for producing fine thread counts. To this end, the directing means are formed by a hollow-cylindrical outlet tube which projects with its free upper end into the cooling cylinder and together with the closed longitudinal section of the cooling cylinder forms an annular inflow gap. In this regard, the cooling air is initially drawn through the inflow gap into the cooling cylinder without contacting the thread filaments. The cooling section in the cooling cylinder, in which the cooling air here shrinks with the thread filaments, can advantageously be influenced by the length of the outlet tube projecting into the cooling cylinder. The thinner the thread filaments, the longer the outlet tube projects into the cooling cylinder.

[0018] In order to ensure that the suction cooling air enters the cooling cylinder exclusively via the inflow gap, it is also provided that the outlet tube passes through the thread outlet and projects with its free lower end from the cooling cylinder. The thread filaments are then guided in a contact-free manner past the hollow-cylindrical outlet tube. The cooling air supplied from the environment then encounters the thread filaments only once in the cooling cylinder.

[0019] In order to produce a uniform suction effect on the gas-permeable longitudinal section of the cooling cylinder, the following inventive refinement is particularly advantageous, the gas-permeable longitudinal section of the cooling cylinder being arranged in a closed suction chamber and the suction chamber being connected to the suction device. The suction chamber thus surrounds the respective longitudinal section of the cooling cylinder to produce a radial air flow from the inside to the outside of the cooling cylinder over the entire longitudinal section. The negative pressure generated in the cooling cylinder here results in the desired counterflow in the entire cooling cylinder. The cooling air consumed for cooling the thread filaments can advantageously be discharged here by means of the suction chamber. As a result, the consumption of cooling air leaving together with the thread bundle is advantageously prevented.

[0020] In order to produce a uniform suction flow acting on the peripheral surface of the gas-permeable longitudinal section of the cooling cylinder, the following inventive refinement proves to be particularly successful, the closed longitudinal section of the cooling cylinder passing through a negative pressure chamber arranged below the suction chamber and being connected to the suction chamber, and the suction device being connected to the negative pressure chamber. A uniform negative pressure acting on the peripheral surface of the gas-permeable longitudinal section of the cooling cylinder can then be produced over the entire cross-sectional area of the suction chamber. A non-uniform distribution of the suction flow in the suction chamber can then be advantageously avoided. The consumption of cooling air entering the suction chamber is received by the negative pressure chamber arranged below the suction chamber and is discharged by means of the suction device.

[0021] In order to be able to use the entire cross-sectional area for discharging the consumption of cooling air, the suction chamber and the negative pressure chamber are connected to one another by means of a gas-permeable bulkhead, wherein the bulkhead forms the bottom of the suction chamber.

[0022] Generally, the production of synthetic yarns takes place in a spinning position in which a plurality of yarns are produced parallel adjacent to each other as a thread group. In this regard, the present application is not limited to cooling a thread group. It is thus possible that a plurality of cooling cylinders are held in the suction chamber with their gas-permeable longitudinal sections. Here, the cooling cylinders are held in a similar manner as the spinning nozzles to be arranged in rows on a spinning beam. The counter gas flow in the plurality of cooling cylinders can then advantageously be generated by one suction chamber.

[0023] The device for cooling a freshly extruded thread bundle according to the present application for producing a synthetic yarn is particularly suitable for large thread counts to achieve a uniform cooling of the thread strands. BRIEF DESCRIPTION OF DRAWINGS

[0024] In the following, the device for cooling a freshly extruded thread bundle according to the present application is explained in more detail by means of several embodiments with reference to the drawings, in which:

[0025] Figure 1 a cross-sectional view of a first embodiment of the device for cooling a freshly extruded thread bundle according to the present application is schematically shown; and

[0026] Figures 2 to 4 a cross-sectional view of a first embodiment of the device for cooling a freshly extruded thread bundle according to the present application is schematically shown; and DETAILED DESCRIPTION

[0027] A cross-sectional view of a first embodiment of the device for cooling a freshly extruded thread bundle according to the present application is schematically shown in Figure 1 . This embodiment has a cooling cylinder 1 which forms a thread inlet 2 at the upper end and a thread outlet 3 at the lower end. The cooling cylinder 1 has a plurality of different longitudinal sections, wherein at least one of the longitudinal sections 1.1 is formed by a gas-permeable cylinder wall 4. The gas-permeable longitudinal section 1.1 of the cooling cylinder 1 is arranged in the upper side region of the cooling cylinder 1 in a manner below the thread inlet 2.

[0028] A closed longitudinal section 1.2 formed by a closed cylinder wall 5 extends below the gas-permeable longitudinal section 1.1. The closed cylinder wall 5 of the closed longitudinal section 1.2 of the cooling cylinder 1 extends to the thread outlet 3. The longitudinal sections 1.1 and 1.2 of the cooling cylinder 1 are preferably arranged by separate cylinder walls 4, 5. In principle, the cooling cylinder 1 can also be embodied in one piece.

[0029] The cooling cylinder 1 penetrates the suction chamber 6 with the gas-permeable longitudinal section 1.1. The suction chamber 6 surrounds the peripheral surface of the cooling cylinder 1 in the region of the gas-permeable cylinder wall 4. The suction chamber 6 is closed off with respect to the environment by means of a chamber housing 6.1. The negative pressure chamber 8, which is penetrated by the closed longitudinal section 1.2 of the cooling cylinder 1, is arranged below the suction chamber 6. The bottom of the suction chamber 6 is formed by a gas-permeable partition 7, which separates the suction chamber 6 from the negative pressure chamber 8. The partition 7 surrounds the cooling cylinder 1 in the transition region between the gas-permeable cylinder wall 4 and the closed cylinder wall 5. The closed longitudinal section 1.2 of the cooling cylinder thus extends in the negative pressure chamber 8 and penetrates the latter. Here, the filament outlet 3 of the cooling cylinder 1 can be arranged on the underside of the negative pressure chamber 8 or spaced apart therefrom. In the embodiment shown, the filament outlet 3 of the cooling cylinder 1 is designed to be spaced apart from the underside of the negative pressure chamber 8. Figure 1 In the embodiment shown, the filament outlet 3 of the cooling cylinder 1 is designed to be spaced apart from the underside of the negative pressure chamber 8.

[0030] The negative pressure chamber 8 surrounds the cooling cylinder 1 with respect to the suction chamber 6 by means of a coaxial cross section. The negative pressure chamber 8 is closed off with respect to the environment by means of a chamber housing 8.1.

[0031] On one side of the negative pressure chamber 8, the chamber housing 8.1 has a suction port 8.2, to which a suction port 9 is connected. The suction port 9 connects the negative pressure chamber 8 to a suction device 10. The suction device 10 has at least one negative pressure source 10.1 for generating a negative pressure in the negative pressure chamber 8. The suction device 10 can generally even have further devices for preparing and filtering the cooling air consumed, which are not shown here.

[0032] A seal 11, which has a cutout 11.1 in the region of the filament inlet 2, is arranged above the suction chamber 6. The seal 11 is conceived to be held in a sealing manner directly at the underside of the spinning beam by the entire cooling device.

[0033] An air directing mechanism 14 is assigned to the filament outlet 3 of the cooling cylinder 1 below the negative pressure chamber 8. The air directing mechanism 14 is formed by an inflow nozzle 15 in this embodiment. The inflow nozzle 15 is assigned to the filament outlet 3 directly at the end of the cooling cylinder 1 and is held on the underside of the negative pressure chamber 8 by a holder, which is not shown here, for example. The inflow nozzle 15 has an outlet cross section 15.2 with respect to the filament outlet 3. An inlet cross section 15.1, which is larger than the outlet cross section 15.2, is arranged on the inflow nozzle 15 with respect to the environment. The outlet cross section 15.2 corresponds to the flow cross section of the cooling cylinder 1. The inflow nozzle 15 between the inlet cross section 15.1 and the outlet cross section 15.2 has a rounded transition wall 15.3. But the transition wall 15.3 of the inflow nozzle 15 can also be configured by means of a cone.

[0034] The device is arranged in operation such that the cooling cylinder 1 is held in an essentially coaxial manner with respect to the spinning nozzle 12. In order to explain the function, the spinning nozzle 12 is arrangedFigure 1 A plurality of filaments threads 13 from a plurality of orifices of the spinning nozzle 12 is extruded via the spinning nozzle 12. The filaments threads are arranged in the form of a bundle and pass through the cooling cylinder 1. For the sake of explanation, the filaments threads 13 are also shown in this embodiment only by dashed lines.

[0035] For cooling the just extruded filament bundle, a negative pressure which is transmitted into the interior of the cooling cylinder 1 by means of the suction chamber 6 and the gas-permeable cylinder wall 4 is generated in the negative pressure chamber 8 by means of the negative pressure source 10.1 of the suction device 10. As a result, a suction effect is generated, so that the inlet cross section 15.1 of the inflow nozzle 15 forms an air inlet. The cooling air which is sucked through the inflow nozzle 15 is directly guided into the cooling cylinder 1 via the filament outlet 3. The cooling air is thus sucked from the environment as counterflow in the cooling cylinder 1 from the filament outlet 3 to the filament inlet 2. The cooling air thus flows counter to the direction of movement of the filaments 13. The bypass flow on the circumference of the filaments threads which is designed when the filaments threads 13 are drawn off can thus advantageously be interrupted by the counterflow of the cooling air for cooling the filaments threads. In addition, the supply of cooling air via the inflow nozzle 15 also leads to a homogenized smooth air flow.

[0036] In Figure 1 The cooling air flow is schematically shown in the subsequent figures by arrows.

[0037] In the course of cooling the filaments threads, the cooling air flow is drawn off through the gas-permeable cylinder wall 4 of the cooling cylinder 1 into the suction chamber 6 and from there to the suction device 10 by means of the negative pressure chamber 8. The cooling air which is consumed for the filament cooling is thus discharged from the process. A run-off into the environment can thus advantageously be avoided.

[0038] At the same time, waste gases, such as monomers or oligomers which occur, for example, below the spinning nozzle when the filaments threads are extruded, can be directly jointly discharged.

[0039] In order to achieve a desirably long cooling distance in the case of a large number of filaments threads and in particular in the case of a comparatively large yarn count, a further embodiment of the device for cooling just extruded filament pieces according to the application in Figure 2 is schematically shown in a cross-sectional view. According to Figure 2 the embodiment is essentially identical to the embodiment according to Figure 1 . In this regard, only the differences will be explained, and reference is otherwise made to the previous description in order to avoid repetition.

[0040] In the embodiment of the device according to the application as shown in Figure 2 the structure of the cooling cylinder 1, the suction chamber 6 and the negative pressure chamber 8 is identical to the previous embodiments. Only the negative pressure source 10.1 of the suction device 10 is different according to Figure 2In the embodiment, the air orientation mechanism 14 assigned to the filament outlet 3 is formed by the inlet cylinder 16. The inlet cylinder 16 is arranged on the filament outlet 3 in the extension of the cooling cylinder 1. The inlet cylinder 16 can also be held on the lower side of the negative pressure chamber 8 by a support (not shown here). The inlet cylinder 16 has a flow cross-section with substantially the same size as that of the cooling cylinder 1 and thus forms an extension of the cooling cylinder 1 at the filament outlet 3. Thus, the inlet cylinder 16 forms an inlet opening 16.1 at the lower end, through which the suction cooling air enters and is guided into the cooling cylinder 1.

[0041] To obtain an ideally uniform air flow towards the cooling cylinder 1, a plurality of inlet openings 16.2 dispersed over the entire circumferential surface are arranged on the cylinder body of the inlet cylinder 16. The inlet openings 16.2 can be formed, for example, by a sieve-like cylinder wall or a perforated metal plate. In this regard, a laterally oriented suction flow is generated in the length range of the inlet cylinder 16, and the laterally oriented suction flow and the axially flowing cooling air are jointly guided to the cooling cylinder 1. The cooling section formed by the inlet cylinder 16 here can especially be additionally used to cool the filament tow by means of the reverse air flow of the cooling air.

[0042] In order for the axially entering cooling air and the radially entering cooling air to interact with each other at the inlet cylinder 16, another embodiment of the device for cooling the freshly extruded filament sheet according to the invention is shown in Figure 3 In the figure. Figure 3 The embodiment of is the same as the embodiment according to Figure 2 Therefore, the previous description also applies here. The only difference from the embodiment according to Figure 2 is that an adjustable outlet hole 17 is arranged at the free end of the inlet cylinder 16. In order to suck the cooling air into the inlet cross-section 16.1 configured at the end of the inlet cylinder 16 can be changed through the outlet hole 17. Thus, the main part of the cooling air supplied through the inlet openings 16.2 on the cylinder body of the inlet cylinder 16 can be obtained. The inlet openings 16.2 on the cylinder body of the inlet cylinder 16 can also be changed here in relation to the distance from the filament outlet 3 in terms of the size of the inlet openings 16.2. The opening width of the inlet openings 16.2 and the number of the opened inlet openings 16.2 on the circumferential surface of the inlet cylinder 16 can also be changed by means of an adjusting device. Thus, flexible cooling conditions for producing different types of yarns can be achieved.

[0043] In order to be able to ideally produce slender filament tows despite the reverse air flow of the cooling air, another embodiment of the device for cooling the freshly extruded filament bundle according to the invention is schematically shown in the Figure 4 Cross-sectional view. The embodiment according to Figure 4 is basically the same as the embodiment according to Figure 1 Therefore, only the differences will be explained here, and reference is also made to the above description.

[0044] In the embodiment of the device for cooling freshly extruded filament bundles according to the application as shown in Figure 4 , the structure of the cooling cylinder 1, of the suction chamber 6 and of the negative pressure chamber 8 is identical to the embodiment according to Figure 1 . Only the air directing means 14 arranged on the underside of the negative pressure chamber 8 in the embodiment according to Figure 4 is formed by an outlet cylinder 18. The outlet cylinder 18 is designed as a hollow cylinder and surrounds the filament thread 13. Here, the outlet cylinder projects with a free upper end into the cooling cylinder 1, wherein the outlet cylinder 18 is designed to be smaller in terms of outer diameter than the inner diameter of the cooling cylinder 1. An annular inflow gap 19 is thus formed between the closed longitudinal section 1.2 of the cooling cylinder 1 and the outlet cylinder 18. For this purpose, the upper end 18.1 of the outlet cylinder 18 is arranged within the cooling cylinder 1. The outlet cylinder 18 passes through the filament outlet 3 and projects from the cooling cylinder 1 by means of a lower end 18.2. This results in the annular inflow gap 19 between the outlet cylinder 18 and the cooling cylinder 1. The cooling air sucked in here by means of the negative pressure within the cooling cylinder 1 is essentially sucked through the annular inflow gap 19 and directed into the cooling cylinder 1. The cooling air hits the filament thread 13 at the upper end 18.1 of the outlet cylinder 18, so that a relatively short cooling section is used for cooling the filament thread. The length of the cooling section can thus be determined by the position of the outlet cylinder 18.

[0045] The device for cooling freshly extruded filament bundles according to the application is suitable for the production of textile yarns and factory yarns or even carpet yarns. It is important here that the filament pieces can be guided in the form of a filament bundle through the cooling cylinder.

Claims

1. A device for cooling freshly extruded filament bundles for producing yarn, which device has a hollow-cylindrical cooling cylinder (1) and has a suction device (10) with which cooling air is drawn through the cooling cylinder (1), characterized in that the cooling cylinder (1) has at least an upper, air-permeable longitudinal section (1.1) and a lower, closed longitudinal section (1.2) between a filament inlet (2) and a filament outlet (3), and the closed longitudinal section (1.2) of the cooling cylinder (1) is assigned an air- directing mechanism (14) at the filament outlet (3), with which air- directing mechanism (14) cooling air drawn by the suction device (10) can be directed to the cooling cylinder (1), wherein the air-permeable longitudinal section (1.1) of the cooling cylinder (1) is arranged in a closed suction chamber (6) and the suction chamber (6) is connected to the suction device (10), wherein the closed longitudinal section (1.2) of the cooling cylinder (1) passes through a negative-pressure chamber (8) which is arranged below and communicates with the suction chamber (6), and the suction device (10) is connected to the negative-pressure chamber (8). The air-directing mechanism (14) is formed by a ring-shaped inlet nozzle (15) which has an inlet cross section (15.1) towards the environment and an outlet cross section (15.2) towards the cooling cylinder (1). The inlet cross section (15.1) of the inlet nozzle (15) is larger than the outlet cross section (15.2) of the inlet nozzle (15), wherein the transition wall (15.3) of the inlet nozzle (15) between the inlet cross section (15.1) and the outlet cross section (15.2) is designed conically and / or is rounded.

2. The apparatus of claim 1, wherein, The air-directing mechanism (14) is formed by a hollow-cylindrical inlet cylinder (16) which has substantially the same size of the flow cross section towards the cooling cylinder (1) and which is held at the filament outlet (3) in the extension of the cooling cylinder (1).

3. The apparatus of claim 2, wherein, The inlet cylinder (16) has a plurality of inlet openings (16.2) on the cylinder body which are designed to be distributed over the entire peripheral surface.

4. The apparatus of claim 1, wherein, The inlet cylinder (16) has an adjustable outlet opening (17) at the free end, with which the inlet cross section (16.1) of the inlet cylinder (16) can be changed.

5. The apparatus of claim 4, wherein, The air-directing mechanism (14) is formed by a hollow-cylindrical outlet cylinder (18) which projects into the cooling cylinder (1) with an upper free end (18.1) and forms a ring-shaped inlet gap (19) together with the closed longitudinal section (1.2) of the cooling cylinder (1).

6. The apparatus of claim 4 or 5, wherein, ​ 7. The apparatus of any one of claims 1 to 3, wherein, ​ 8. The apparatus of claim 7, wherein, The outlet cylinder (18) passes through the filament outlet (3) and projects from the cooling cylinder (1) by means of a free lower end (18.2).

9. The apparatus of claim 1, wherein, The suction chamber (6) and the negative pressure chamber (8) are connected to one another by means of a gas-permeable partition (7), wherein the partition (7) forms the bottom of the suction chamber (6).

Images