Apparatus for producing a plurality of filaments

Abstract

The present invention relates to an apparatus and method for producing a plurality of filaments (13) for forming a yarn (17), comprising a spin pack (21) positioned on a spinning beam (2) for extruding the plurality of filaments (13) from a capillary (22), a cooling duct (1) capable of guiding the filaments (13), and a counter-volume flow device (20) capable of cooperating with the cooling duct (1) to generate a counter-volume flow (30) in the cooling duct (1) against the filament running direction (F). The counter-volume flow (30) is generated by the counter-volume flow device (20) in a direction opposite to the filament running direction (F) by volumetric suction.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for producing a plurality of filaments for forming a yarn according to the preamble of claim 1 and to a corresponding method for producing a plurality of filaments for forming a yarn according to the preamble of claim 15. [Background technology]

[0002] In the production of composite yarns, it is common knowledge that multiple thin filament strands are extruded from a polymer melt through multiple capillaries in a spin pack. The filament strands then form a bundle that is then cooled and assembled into a yarn. To prevent the filament strands from bonding together within a single yarn assembly, the filament strands must be cooled after extrusion for hardening. Cooling of the filament strands is typically achieved by a cooling flow acting on the filament strands. However, in this case, as many filament strands as possible within the filament bundle must be uniformly cooled to achieve as uniform physical properties as possible.

[0003] Many devices are known from the prior art for cooling freshly extruded filament strands, which can be substantially divided into groups for generating cooling air flows.

[0004] One group concerns transverse flow blowing devices, for example DE 44 04 258 A1, in which a transversely directed cooling flow is directed at the extruded filament strand.

[0005] Although this type of cooling has a relatively good cooling effect, it has the drawback that the cooling flow is applied to the filament bundle only on one side.

[0006] Another type of cooling is known as a radial blowing device. U.S. Pat. No. 5,219,582 describes a radial blowing device in which the filament bundle is guided in a cylindrical cooling duct with gas-permeable walls and located in a blow chamber. Cooling air guided into the blow chamber enters the cooling duct from the outside through the gas-permeable walls to the inside, cooling the filament strand.

[0007] Such radial blowing devices have the disadvantage that the cooling air is directed in the same direction as the filament strands, in the direction of yarn travel, and this reduces the cooling effect, especially with radial blowing, because a sheath flow forms around the filament strands, which can shield the filament strands from the cooling air or prevent them from contacting the cooling air.

[0008] Another cooling variant known from the prior art is to generate a cooling flow which is arranged in a direction opposite to the yarn running direction.

[0009] Here, for example, a vacuum suction device is used, which is known, for example, from DE 1 119 456. This document discloses a so-called cooling cylinder with a suction element acting on the region of the spinning nozzle and the cooling cylinder.

[0010] However, the blotter generates undesirable air turbulence that can adversely affect the uniformity of cooling of the filament strands.

[0011] To counteract this air turbulence, so-called suction chambers are known, which are connected to a vacuum chamber that concentrically surrounds the cooling cylinder, as is known, for example, from DE 10 2021 000 436 A1. Again, a large vacuum is required, which must be generated by the suction chamber, particularly in order to allow cooling of the filaments in the cooling ducts. This cooling device, too, has proven to be unreliable. Summary of the Invention [Problem to be solved by the invention]

[0012] The object of the present invention is to provide an apparatus and method that can reduce or avoid the above-mentioned drawbacks when cooling multiple filaments. [Means for solving the problem]

[0013] As regards the device, this problem is solved according to the invention by a device having the features of claim 1.

[0014] As regards the method, this problem is solved according to the invention by a method having the features of claim 15.

[0015] Advantageous developments of the invention are defined by the features and feature combinations of the respective dependent claims.

[0016] According to one aspect of the present invention, there is provided an apparatus for producing a plurality of filaments for forming a yarn, the apparatus comprising: a spin pack positioned on a spin beam for extruding the plurality of filaments from a capillary; a cooling duct capable of guiding the filaments; and a counter-volume flow device capable of cooperating with the cooling duct to generate a counter-volume flow in the cooling duct against the filament running direction, the counter-volume flow being generated by the counter-volume flow device in a direction opposite to the filament running direction by volumetric suction.

[0017] Volumetric suction has the advantage that it is independent of external air pressure fluctuations, since the counter-flow device used for volumetric suction can be considered a closed system.

[0018] The great advantage is that it is possible to absorb almost any volume flow rate and this can be done independently of external conditions.

[0019] Depending on the volume flow used, a turbulence-free or low-turbulence flow is produced. Furthermore, counterflow cooling allows for better utilization of the cooling air, particularly turbulence-free or low-turbulence, since the air is sucked in by volume-flow suction rather than via negative pressure.

[0020] Any volumetrically conveying displacer device can be used for the volumetric flow suction. Furthermore, the air used for cooling or for the counterflow does not have to be specially cooled, since the cooling is carried out in a counterflow manner. The air used for the counterflow can be obtained, for example, directly from the surrounding area where the device is accommodated. Counterflow cooling additionally provides additional air conditioning of the hangar, which can also save additional costs.

[0021] Volumetric suction is to be understood here in particular as the generation of a volumetric flow with very little pressure, which can occur with little turbulence or almost completely without turbulence.

[0022] Furthermore, the volumetric suction can be carried out independently of the ambient pressure, since the transport takes place in a closed system in which the displacer body causes a periodic volume change in working chambers provided for this purpose, which working chambers can be separated from the supply and discharge lines by separating elements, so that the volumetric suction is not influenced by the ambient pressure present, since the system is closed and can generate a flow independently of the ambient pressure.

[0023] According to one embodiment of the device, the counter-volume flow device is positioned between the spin pack and the cooling duct, which has the advantage that a counter-volume flow can be introduced directly into the capillaries of the spin pack, and therefore cooling can also be carried out directly by counterflow at the spin pack and the filaments generated thereby.

[0024] According to one embodiment of the apparatus, the cooling duct has a filament inlet positioned adjacent to the spinning beam and a filament outlet positioned adjacent to a convergence point where multiple filaments are gathered into a yarn.

[0025] The advantage of this is that a counter-flow can act over the entire length of the cooling duct, and the cooling of the filaments occurs in the counter-flow direction without creating a sheath flow on the filaments.

[0026] Therefore, countercurrent flow can be achieved at much lower velocities and with smaller volumes, which also requires less suction cost.

[0027] A convergence point is understood here to mean a point where several filaments are brought together into one yarn, which can be done, for example, via a dedicated device having a yarn guide with an additional spin finishing device.

[0028] In this case, the spin finishing device and the yarn guide may be spaced apart. The spin finishing device is used to apply preparation oil to the extruded filaments.

[0029] According to another embodiment of the device, the cooling duct has an air-permeable wall section for guiding a counter volume flow parallel to the filament running direction.

[0030] The advantage of this is that the cooling effect of the counter-current volumetric flow is additionally enhanced by the additional guidance in the cooling duct in the direction of filament travel, thus resulting in a gentler and simultaneously better cooling of the filaments.

[0031] According to another embodiment of the device, the cooling duct has an air-permeable permeable section for guiding a counter volume flow transversely to the filament direction.

[0032] The term "permeable section" here is understood to mean, in particular, an additional or complete wall section of the cooling duct, which allows the supply of ambient air not only in the yarn guiding direction but also transversely to this yarn guiding direction, and a countercurrent flows through the permeable section or the permeably configured wall section of the cooling duct, into the interior of the cooling duct, and thus flows countercurrently towards the spin pack, also in the direction of filament travel or transversely to the filament travel direction, which, on the other hand, prevents the formation of a sheath flow in the filaments, thereby enabling better and gentler cooling.

[0033] According to another embodiment of the device, the cooling ducts have a substantially circular and / or substantially rectangular cross section, which has the advantage that, depending on the circumference, they can be guided radially and / or transversely counter to the running direction of the filaments.

[0034] Furthermore, in certain circumstances and applications, a circular or rectangular cross section of the cooling duct may be advantageous.

[0035] According to another embodiment of the device, the cross-section of the cooling duct at the yarn inlet is larger than the cross-section of the cooling duct at the yarn outlet and / or the cross-section of the cooling duct at the yarn inlet is smaller than the cross-section of the cooling duct at the yarn outlet.

[0036] The advantage of this is that in the first embodiment, when viewed from the yarn running direction towards the spin pack, a conical cooling duct is defined which narrows the counterflow, which allows for better cooling and at the same time allows for more air to be sucked in at the lower end of the cooling duct, the tapering towards the spin pack increasing its speed.

[0037] In the other embodiment, where the cooling ducts have a larger cross section towards the spinning nozzle, this reduces the volume flow velocity and allows for gentle cooling, in particular preventing the formation of turbulence and sheath flow in the filaments.

[0038] According to one embodiment of the device, the counter-volume-flow device has a conveying housing in which a volume flow intake is arranged.

[0039] The advantage that this offers is that it allows the construction of a closed system which can be isolated from environmental influences by means of corresponding closing and isolating means.

[0040] According to another embodiment of the device, the conveying housing and the spinning beam are fluid-tightly connected to a channel for supplying the counterflow, the advantage of which is that the conveying housing can be positioned in a predetermined position relative to the spinning beam without heat from the spinning beam impairing the formation of the counterflow volume.

[0041] According to another embodiment of the device, the flow path is connected to a heat exchanger for cooling the counter-volume flow, which additionally allows for direct removal of the heat radiation originating from the spinning beam and the hot plastic melt without resulting in a temperature load on the counter-volume flow and associated components.

[0042] In another embodiment of the device, the transport housing has an air outlet connected to the suction device. The advantage of this is that the countercurrent flow collected in the transport housing can be discharged at the air outlet, which is fluid-tightly connected to the suction device and can therefore transport the air flow generated away from the cooling duct and the surroundings of the spinning nozzle without undesirably increasing the temperature when cooling the filaments. In a special development of the device, the volumetric flow intake is a displacer pump.

[0043] According to another embodiment of the device, the counter-volume flow device has a volume flow intake device that delivers the counter-volume flow into the closed volume, the advantage of which, as indicated above, is that the system is closed and thus protected from external environmental influences.

[0044] According to another embodiment of the device, the volumetric flow intake is provided with a volumetric flow rate of 1 m 3 relative to the yarn mass to be cooled in order to convey the countercurrent. 3 / kg~15m 3 / kg. Depending on the yarn mass to be cooled, a larger or smaller countercurrent flow is required. For small yarn masses, a small countercurrent flow may be sufficient, whereas for large yarn masses, a larger countercurrent flow is required.

[0045] According to another embodiment of the device, the number of volumetric flow inlets corresponds to the number of spin packs, with the advantage that in the case of several spin packs, the volumetric flow can be set individually for each spin pack, thereby allowing optimal cooling of the filaments of each spin pack.

[0046] The volume flow intake is preferably designed so that it can be replenished depending on the number of spin packs provided.

[0047] According to another aspect of the present invention, there is provided a method for producing a plurality of filaments for forming a yarn, comprising extruding the plurality of filaments from a plastic melt, cooling them in a cooling duct, and generating a counter volumetric airflow flowing counter to the yarn arrangement of the filaments to cool the filaments.

[0048] The advantage of this is that, as mentioned above, the volumetric blotting can be created independent of given ambient environmental conditions.

[0049] In another embodiment of the method, the opposing volume flows are arranged parallel to the yarn guiding direction and / or transverse to the yarn guiding direction.

[0050] By forming and guiding a counterflow volume in the direction opposite to the yarn guiding direction or transverse to the yarn guiding direction, it is possible to simply prevent sheath flows that would shield the filaments from cooling.

[0051] In another embodiment of the method, the countercurrent conveying rate can be set depending on the filament discharge rate, the yarn mass of the extruded filaments, the specific heat capacity of the melt, the specific heat capacity of the total volume, the ambient temperature, the melt temperature, the filament temperature and / or the filament count.

[0052] The advantage of this is that the method used in the device can be optimally configured to cool each filament, and the total volume used to cool the filaments is removed from the ambient environment in which the device or method is applied.

[0053] The device according to the invention and the method according to the invention for producing a plurality of filaments for forming a yarn will now be described in more detail on the basis of several embodiments and with reference to the accompanying drawings. [Brief explanation of the drawings]

[0054] [Figure 1] 1 is a schematic cross-sectional view of a first embodiment of an opposed volumetric flow device according to the invention in a cooling duct of an apparatus for producing a plurality of filaments; FIG. [Figure 2] 2 is a plan view of the opposed volumetric flow device shown in FIG. 1 for a predetermined number of spin packs. [Figure 3] 1 is a schematic block diagram of the steps of a method according to the present invention for producing a plurality of filaments for forming a yarn. DETAILED DESCRIPTION OF THE INVENTION

[0055] In Figures 1 and 2, a reference coordinate system with XYZ directions is predefined in each figure, which reference coordinate system extends in the respective main directions of extension of the devices shown therein.

[0056] In Figure 1, the reference coordinate system XYZ indicates the longitudinal extension direction of the device for producing multiple filaments 13 in the X direction, the depth extension direction of the device in the Y direction, and the height extension direction of the device in the Z direction.

[0057] In FIG. 2, a reference coordinate system XYZ is shown in a plan view of the device according to the invention with a spinning beam and a counter-volume-flow device 20, the reference coordinate system indicating in the X direction the longitudinal extension of the counter-volume-flow device, in the Y direction the depth extension of the counter-volume-flow device or in the Z direction the height of the counter-volume-flow device.

[0058] 1 shows in schematic cross section an embodiment of an apparatus for producing a plurality of filaments to form a yarn 17. The apparatus comprises a spin beam 2 on which is positioned a spin pack 21 having a plurality of capillaries 22 through which a plastic melt is extruded to form a plurality of filaments 13 which are gathered into a yarn 17 at a convergence point 18.

[0059] A cooling duct 1 is arranged adjacent to the spinning beam 2 in order to sufficiently cool the plurality of filaments 13 .

[0060] The cooling duct 1 has a filament inlet 6 through which the filaments 13 are fed into the cooling duct from the spinning beam 2, and a filament outlet 3 through which the filaments exit the cooling duct 1. The cooling duct preferably has a substantially rectangular cross-section, but may also have a substantially circular cross-section.

[0061] The cooling duct 1 further comprises a wall section 5. In the illustrated embodiment, the cooling duct 1 is both permeable and non-permeable. The wall section 5 is configured to be non-permeable. The wall section 5 is adjacent to the non-permeable permeable section 4, so that ambient air can be sucked through the permeable section 4 by the volume flow intake 12 in order to cool the filaments 13.

[0062] An advantage of the non-air-permeable wall section 5 is that the counter-volume flow 30 sucked in by the counter-volume-flow device 20 runs substantially parallel to the filament running direction F. As shown in FIG. 1 , the course of the counter-volume flow 30 is opposite to the filament running direction F, which additionally facilitates cooling of the filaments 13.

[0063] The counter-volume flow device 20 is configured so that the ambient pressure P1 and the internal pressure P2 in the cooling duct are equal, the advantage of which is that the counter-current flows towards the filaments 13 with little or no turbulence.

[0064] This promotes solidification of the filaments at the point of convergence 18, where the filaments 13 are gathered into a yarn 17. The point of convergence 18 may additionally be coated with a so-called spinfinishing, which is a liquid emulsion of water and oil, which promotes slip, reduces friction and acts as an anti-static agent.

[0065] The internal pressure P2 in the cooling duct is less than the suction pressure P3 generated by the opposed volumetric flow device 20.

[0066] The counter-volume flow device 20 comprises a conveying housing 10 in which a volume flow intake 12 is accommodated. The volume flow intake 12 is connected to the spinning beam 2 via a channel 11.

[0067] In order to reduce or avoid heat transfer from the spinning beam to the counter-volume flow device 20, the flow path 11 may be provided with a heat rejection section 7, which is connected via a heat exchange line 8 to a heat exchanger 9, thereby removing or reducing the heat input that occurs.

[0068] The conveying housing 10 of the volumetric flow intake 12 further has an air outlet 14. A suction device 16 can be connected to the air outlet 14, which suctions and discharges the counterflow 30 volumetrically drawn in by the counter-volume-flow device 20 via an air outlet line 15 separately from the counter-volume-flow device 20. "Separately" here can be understood to mean that the suction device 16 does not influence the conveying output of the counter-volume-flow device 20.

[0069] Figure 2 shows a schematic plan view of the spinning beam of Figure 1 with a number of spinning packs 21. In the illustrated embodiment, each spinning beam 21 is associated with a volume flow intake 12 housed in a transport housing 10.

[0070] Furthermore, each flow path 11 is associated with a further heat transfer section 7 which is connected to a heat exchanger 9 via a heat exchange line 8 .

[0071] In an embodiment not shown, the heat exchange sections may be formed in one common flow path 11 .

[0072] The counter-volume-flow device 20 may also have individual volume-flow inlets for several spin packs 21. In this case, individual control of the counterflow for each spin pack in the cooling duct 1 is only possible to a limited extent. For this purpose, corresponding baffles (not shown here) may be provided, which allow the counterflow 30 to be directed in a corresponding manner so that an excessively large pressure difference does not arise in the cooling duct 1 with the cooling duct pressure P2 relative to the ambient pressure P1.

[0073] As can further be seen, the volume flow intakes 12 are driven by a common drive 110, which generates respective counterflows 30.

[0074] The volume flow intakes 12 may have corresponding gears, which allow the respective conveying powers to be set individually. In an embodiment not shown, each volume flow intake 12 may have its own drive 110.

[0075] The counterflow 12 volumetrically drawn by the volumetric flow intake 12 is delivered to the air outlet 14. The air outlet 14 can be connected to an air outlet line 15, but the air outlet line 15 does not affect the delivery output of the volumetric flow intake 12.

[0076] For simplicity, the volumetric flow intake 12 is shown as an external gear pump. In a preferred embodiment (not shown), the conveying wheels or conveying fins of the volumetric flow intake 12 are configured aerodynamically efficient, so that a turbulence-free conveyance of the counterflow 30 is possible.

[0077] In FIG. 3, a schematic block diagram is shown illustrating the individual steps of the method for producing a yarn 17 from multiple filaments.

[0078] In a first step S1, a plurality of filaments 13 are extruded from a plastic melt using a spin pack 21 having a plurality of capillaries 22 and arranged on a spin beam 2.

[0079] In another step S2, the filaments 13 are guided through the cooling duct 1 using the convergence point 18 of a winding device (not shown), whereby the filaments 13 are cooled and solidified within the cooling duct 1.

[0080] In step S3, before step S2, a counterflow 30 is generated using the counter volumetric flow device 20. Since the counterflow 30 is generated volumetrically, the ambient pressure P1 does not change with the internal pressure P2 of the cooling duct, and P1 is substantially equal to P2.

[0081] The volumetric generation of the counterflow 30 results in a turbulence-free or less turbulent counterflow 30, which acts in the yarn running direction F and thus results in better cooling of the filaments 13.

[0082] In step S4, the plurality of filaments 13 are guided from the filament outlet 3 away from the cooling duct 1.

[0083] In step S5, the generated heat is discharged via the heat exchanger 9 in the counter volumetric flow device 20.

[0084] In step S6, the counterflow 30 that occurs is additionally sucked out via the suction device 16, and in step S7, the exhaust air is collected using a suction device or via a corresponding device that transports the generated volume of the counterflow 30 around the spinning beam 2 or from the countervolume flow device 20. [Explanation of symbols]

[0085] 1 Cooling duct 2. Spinning beam 3 Filament outlet 4 Transmission section 5 wall division 6 Filament inlet 7. Heat Dissipation Classification 8 Heat exchange line 9 Heat exchanger 10 Transport housing 11 Flow path 12 Volume flow intake 13 Filaments 14 Air outlet 15 Air outlet pipe 16 Debris removal device 17 Thread 18 Convergence points 20 Counter volume flow device 21 Spinning Pack 22 Capillary 30 Countercurrent Volumetric Flow 110 Drive unit p1 first pressure p2 second pressure p3 Third pressure F Filament running direction m extruded filament yarn mass cp specific heat capacity of plastic melt cg Specific heat capacity of the total volume Tt Fineness / Count Tu ambient temperature Ts melting temperature Tf Filament temperature

Claims

1. 1. An apparatus for producing a plurality of filaments (13) for forming a yarn (17), the apparatus comprising: a spin pack (21) positioned on a spinning beam (2) for extruding the plurality of filaments (13) from capillaries (22); a cooling duct (1) capable of guiding the filaments (13); and a counter-volume flow device (20) capable of cooperating with the cooling duct (1) to generate a counter-volume flow (30) in the cooling duct (1) toward a filament running direction (F), characterized in that the counter-volume flow (30) is generated in a direction opposite to the filament running direction (F) by volumetric suction using the counter-volume flow device (20).

2. 2. The device according to claim 1, characterized in that the counter-volume flow device (20) is positioned between the spin pack (21) and the cooling duct (1).

3. 3. The device according to claim 1, wherein the cooling duct (1) has a filament inlet (6) positioned adjacent to the spinning beam (2) and a filament outlet (3) positioned adjacent to a convergence point (18) where a plurality of the filaments (13) are gathered into one yarn (17).

4. 4. The device according to claim 1, wherein the cooling duct (1) has a non-permeable wall section (5) for guiding the counter-flow volume flow (30) parallel to the filament running direction (F).

5. 5. The device according to claim 1, wherein the cooling duct (1) has an air-permeable permeable section (4) for guiding the counter volume flow (30) transversely to the filament running direction (F).

6. 6. Device according to at least one of claims 1 to 5, characterized in that the cross section of the cooling duct (1) is substantially circular and / or substantially rectangular.

7. 7. The device according to claim 1, wherein the cross-section of the cooling duct (1) at the yarn inlet (6) is larger than the cross-section of the cooling duct (1) at the yarn outlet (3) and / or the cross-section of the cooling duct (1) at the yarn inlet (6) is smaller than the cross-section of the cooling duct (1) at the yarn outlet (3).

8. 8. The device according to claim 1, wherein the counter-volume-flow device (20) has a conveying housing (10) in which a volume flow intake (12) is arranged.

9. 9. The device according to claim 1, wherein the conveying housing (10) and the spinning beam (2) are fluid-tightly connected to a flow channel (11) for supplying the counterflow volume (30).

10. 10. The device according to claim 1, wherein the flow path (11) is connected to a heat exchanger (9) for cooling the counter-volume flow (30).

11. 11. Device according to at least one of the preceding claims, characterized in that the transport housing has an air outlet (14) connected to a suction device (16).

12. 12. The device according to claim 1, wherein the counter-flow device (20) has a volumetric flow intake (12) for conveying the counter-flow volumetric flow (30) in a closed volume.

13. To convey the counterflow, the volumetric flow intake (12) must be larger than 1 m3 relative to the yarn mass to be cooled. ３ / kg~15m ３ 13. The device according to claim 1, wherein the weight of the device is in the range of 1 / kg.

14. 14. The device according to claim 1, wherein the number of volumetric flow inlets (12) corresponds to the number of spin packs (21).

15. 1. A method for producing a plurality of filaments (13) for forming a yarn (17), comprising extruding the filaments from a plastic melt and cooling them in a cooling duct (1), and generating a counter-current volumetric flow (30) flowing counter to the yarn guiding direction (F) of the filaments (13) for cooling the filaments, characterized in that the counter-current air flow (30) is generated by means of volumetric suction.

16. 16. The method according to claim 15, characterized in that the counter volume flow (30) is formed opposite to the yarn guiding direction (F) and parallel and / or transverse to the yarn guiding direction (F).

17. 17. The method according to claim 15, wherein the conveying amount of the countercurrent (30) can be set depending on the discharge speed (v) of the filaments (13), the yarn mass (m) of the extruded filaments, the specific heat capacity (cp) of the plastic melt, the specific heat capacity (cg) of the total volume (V), the ambient temperature (Tu), the melting temperature (Ts), the filament temperature (Tf) and / or the count (Tt) of the filaments (13).

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