MXPA00008285A - Process and apparatus for the spinning of a multifilament yarn - Google Patents

Abstract

Extruded filaments (8) are formed into a group and pass through a cooling zone (4) where they are cooled by a coolant flow, but do not solidify. Further cooling and final solidification occurs in a stressing zone (6) below the cooling zone. Cooling conditions in the cooling zone can be varied to influence the location of the solidification area within a set section of the stressing zone. An Independent claim is made for the process plant which has upper (5) and lower (7) cooling shafts, a coolant flow producer (20) and apparatus (10) for varying the position of filament solidification inside the lower cooling shaft.

Description

METHOD AND APPARATUS FOR MILLING IN FLOWED STATE ONE THREAD OF VARIOUS FILAMENTS BACKGROUND OF THE INVENTION The invention relates to a method and apparatus for spinning a multi-filament yarn from a thermoplastic material, and of the general type described in EP 0 682 720 and the corresponding U.S. Patent No. 5,976,431. In spinning by the known method and apparatus, a stream of air aids in its advance the recently extruded filaments. With this, it is achieved that the solidification zone of the filaments moves away from the row. This again leads to a delayed crystallization, which has a favorable effect on the physical properties of the yarn. For example, in the production of a POY yarn, it was possible to increase the withdrawal speed and thus, the suction ratio, without changing the elongation values for the yarn, which are necessary for further processing. For this purpose, the known apparatus comprises current below the spinneret, a cooling device, which includes an upper cooling shaft and a lower cooling shaft connected to the upper cooling shaft at its end. At the outlet, the lower cooling shaft is connected to a cooling current generator, which generates a vacuum in the lower cooling shaft. The upper cooling shaft becomes gas permeable, so that the vacuum prevailing in the lower cooling shaft causes a stream of air to flow to the upper cooling shaft and advances in the direction of the lower cooling shaft. In doing so, a refrigerant stream having a flow velocity substantially equal to the forward speed of the filaments is generated. This has an influence on the friction between the filaments and the adjacent air layer such that the crystallization starts with a delay and the filaments solidify in a solidification zone within the lower cooling shaft. However, it has been shown that in the spinning of fine filament deniers, for example 1 dtex / fo less, the crystallization of the filaments has progressed, after a pre-cooling in a cooling zone formed by the upper cooling shaft , to such a degree that the subsequent assistance in continuous advancement no longer shows a significant influence on the delay of crystallization. The U.S. No. 4,277,430 discloses a method and apparatus, wherein the filaments are cooled in the cooling zone under the row by directing them to a transverse air flow. Underlying the cooling zone is a second cooling shaft, which receives an air / water mixture as a misty cooling current in its inlet area. For cooling the yarn, the misty air stream is caused to flow by suction in the direction of the advancing yarn to the end of the cooling zone. In this process, the addition of liquid constitutes an even greater cooling effect on the filaments, so that the start of crystallization is not delayed but accelerated. It is an object of the present invention to further develop a method of the kind initially described as well as an apparatus for carrying out a method in such a way that it becomes possible to produce them with low, medium or high deniers at higher production speeds and with properties uniform physical BRIEF DESCRIPTION OF THE INVENTION The invention is based on the knowledge that from its emergence from the row to its solidification and yarn formation, the crystallization of the filaments is determined by two mutually influential effects. It is known that during the cooling of a polymer melt, the melt solidifies at a certain temperature. This process is dependent only on the temperature, and called in the present thermal crystallization. In yarn spinning, a bundle of filaments is removed from the rows. In this process, the yarn undergoes withdrawal forces, which effect a stress-induced crystallization in the filaments. In this way, yarn spinning is generated, thermal crystallization and stress-induced crystallization overlap, and together lead to the solidification of the filaments. To influence the stress-induced crystallization, the bundle of filaments is guided, before solidification, in a tension zone, in which the friction of the yarn is changed and in this way, the tension of the yarn acting in the thread. In this way the invention makes available a method and an apparatus which make it possible to influence the stress-induced crystallization under substantially unchanged conditions. For this purpose, the cooling of the filaments, after their emergence from the spinneret, is adjusted within the cooling zone such that the location of the solidification zone of the filaments is maintained within the tension zone in a desired range. , default of it. In this way, the solidification of the filaments in the zone of tension in the lower cooling shaft always occurs essentially in the same place, so as to ensure a uniform treatment of the filaments to influence the crystallization induced by tension. In order to influence the thermal crystallization, it is necessary that the cooling effects that the refrigerant exerts in the cooling zone become variable. However, in this regard, it is necessary that before their entry into the tension zone, the filaments already have a certain stability, in particular in their outer edge layers, for purposes of resisting without damage the refrigerant current, which is generated in the tension zone to treat the thread tension. A particularly advantageous variant for controlling the cooling is provided by a further development of the invention, wherein the refrigerant is quenched before it enters the cooling zone. In this case, the temperature of the coolant can be increased to a value preferably in a range of 20 ° C to 300 ° C. For spinning a yarn, for example, with a relatively low filament denier, the refrigerant is pre-heated to a higher temperature by a heating device, which is used as a medium. This influences the thermal crystallization in such a way that the filament bundles do not solidify before they enter the tension zone. In this way, an advantageous tension treatment is possible by a cooling current directed parallel to the filaments. This current causes the filaments to solidify in the desired range of the tension zone. In the case that it is proposed to spin a yarn of a higher denier, the refrigerant will be adjusted to a lower temperature, so that before entering the tension zone, the thermal crystallization developed so far that the filaments exhibit adequate stability when they attack by the refrigerant current. To adjust the cooling in the cooling zone, an advantageous, further improvement of the invention proposes to change the flow volume of the refrigerant. The means used for this purpose is a blower, which can be used to control the volume of flow that is blown in the cooling zone. At this point, it should be noted that basically all known means for influencing the cooling effect in the cooling zone are suitable for the use of the method of the present invention for spinning a yarn. The means described herein are particularly suitable for the case, when the cooling air, or refrigerant, is used. For example, when a gaseous refrigerant is used, it will be possible to influence the cooling effect only by the vapor state. Likewise, it is possible to use a means in the form of devices to influence cooling in the cooling zone, such as, for example, the moving sheet elements, which influence the coolant inlet in the cooling zone. To ensure great uniformity in the spinning of the filaments, a further, preferred development of the invention provides that the refrigerant stream is accelerated at the flow rate necessary to treat the tension of the bundle of filaments, only in an acceleration zone within the filament. the tension zone. By doing so, the refrigerant stream is accelerated to at least one flow rate, which is equal to the forward speed of the filaments, so that the filaments do not decelerate in their continuous movement. In this way, in order to achieve an optimum crystallization induced by tension, the areas desired to solidify the filaments extend in or directly current under the acceleration zone of the refrigerant. The refrigerant current in the voltage zone can be generated from the refrigerant leaving the voltage zone and from a refrigerant supplied in the input area of the current voltage zone below the cooling zone. This construction allows stress induced crystallization to be adjusted within a wide range. The additionally supplied coolant also allows an influence of the cooling of the filament bundle in the tension zone. In particular, in spinning yarns with higher deniers, the supply of an additional coolant makes it possible to achieve a desired maximum cooling at the outlet end of the tension zone when the yarn is combined. The method of the present invention is independent of whether the cooling current in the tension zone is generated by a suction effect or by a blowing action. The variant of the method, where a suction flow prevails in the tension zone, has the advantage that the thermal crystallization in the cooling zone and the stress-induced crystallization in the tension zone can be influenced in a substantially independent manner between yes. To generate a cooling current by blowing action, it is possible to blow the coolant in the cooling zone and guide it correspondingly in the tension zone, or blow the coolant, downstream of the cooling zone directly in the tension zone . To obtain an effect of the refrigerant current, which is as uniform as possible in each bundle of filaments, the tension zone can be formed by a cooling conduit through which the filaments advance, and which has at its input end a narrow cross section that operates as an acceleration zone for air entering the conduit. Based on its flexibility, the method of the present invention is especially suitable for spinning polyester, polyamide, or polypropylene yarns. A subsequent treatment of the yarn, which is suitable after spinning, makes possible its use in the method to produce, for example, a fully pulled yarn (FDY) a partially oriented yarn (POY), or a highly oriented yarn (HOY). The method of the present invention can be carried out very advantageously by an apparatus, wherein the cooling device comprises an upper cooling shaft and a lower cooling shaft. The cooling shaft extends directly downstream of the spinneret, and forms a cooling zone, in which thermal crystallization is influenced by a coolant introduced into the cooling shaft. The lower cooling shaft is connected to the upper cooling shaft, and forms the tension zone. To generate a cooling current flowing parallel to the wire, the cooling device includes a cooling current generator. This cooling current generator is used to generate a cooling current with a predetermined flow rate. According to the invention, the apparatus for carrying out the method comprises a means for adjusting the cooling of the filaments in the upper cooling shaft. This means allows the influence of the cooling of the filaments in such a way that the filaments solidify only in a predetermined, desired range of the lower cooling shaft. In this way, the apparatus of the present invention is suitable for changing the location of the solidification zone of the filaments along the spinning line, in particular in the region of the lower cooling shaft. It is possible to use a means both of devices that are operative in the cooling device and devices, which act directly on the refrigerant. Advantageously, with the use of cooling air, the medium is designed and constructed as a heating device, which anneals the cooling air entering the lower cooling shaft. In this case, the cooling device is operated via a controller with corresponding predetermined control values. In order to generate a uniform cooling current in the lower cooling shaft as much as possible, it is particularly advantageous to form an acceleration zone in the cooling shaft by means of a narrow cross-section. A coolant entering the lower cooling shaft in this manner is accelerated to a flow rate, which depends essentially on the pressure difference prevailing between the inlet side and the inside of the cooling shaft. To generate the pressure difference to develop a cooling current in the lower cooling shaft, it is possible to use as the cooling current generator both a blower that blows the refrigerant in the lower cooling shaft, and a vacuum source, which is connects to the lower cooling shaft on the output side thereof, and sucks the coolant into the lower cooling shaft. To produce qualitatively superior yarns, the lower cooling shaft can be formed by a tube, through which the bundle of filaments advances. The input end mounts a condenser and the output end a diffuser. The condenser generates a uniform cooling current, which surrounds the bundle of filaments. The diffuser produces a slow decrease in the flow rate of the refrigerant stream, so that the bundle of filaments advances through the lower cooling shaft in a substantial manner with little turbulence. To improve the smooth run of the filament bundle and to avoid stronger turbulence in the cooling shaft, a further, very advantageous development of the apparatus provides a second condenser between the upper and lower cooling shafts. This second condenser ensures a substantially turbulent free transition of the coolant from the upper cooling shaft to the lower cooling shaft. In this case, the acceleration zone, which is characterized by a narrower cross section of flow, can be formed in both the first and the second condenser. In order to increase the cooling effect, in particular in the case of thicker wire deniers, it will be advantageous to introduce an additional coolant in the voltage zone between the two capacitors.

BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the apparatus according to the invention as well as the advantageous effects of the method according to the invention are described in more detail below with reference to the drawings, in which: Figure 1 is a schematic view of a first embodiment of an apparatus according to the invention for carrying out the method of the present invention; and Figures 2-4 are schematic views of additional embodiments of the apparatus according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 schematically illustrates a first embodiment of an apparatus according to the invention for spinning a multi-filament yarn, and wherein a yarn 26 is spun from a thermoplastic material and wound onto a bundle 25 in the receiving device 24. For this purpose, the thermoplastic material is melted in an extruder and a spin pump (not shown) distributes the melt via a line 3 of melt to a heated rotating head 1. The lower side of the rotating head 1 assembles a row 2. From row 2, the melt emerges in the form of fine strands and filaments 8. The filaments 8 advance through a cooling zone 4, which is formed by a tree 5 upper cooling. For this purpose, the cooling shaft 5 is arranged directly downstream of the rotary head 1, and surrounds the filaments 8 with a gas-permeable wall 9. On the outer side of the walls 9, the cooling shaft 5 comprises an air inlet 33, which opens to the environment. In the air inlet 33, a heater 10 is arranged, which heats a stream of air introduced from the outside, before it enters the wall 9 permeable to gas. The heater 10 is connected to a controller 11. In the direction of advancement of the thread downstream of the upper cooling shaft 5, a second cooling shaft 7 extends, forming a zone of tension 6 to influence the friction of yarn and this way, a voltage-induced crystallization. The lower cooling shaft 7 is designed and constructed as a tube 12. The input side of the cooling shaft 7, the tube 12 assembles a condenser 14, which is connected to the outlet side of the upper cooling shaft 5. The condenser wall 14 contains a plurality of inlet openings 15.1 and 15.2. The embodiment shows, for example, two inlet openings, which are arranged in symmetrical relationship with the circumference of the condenser 14. On the outlet side of the lower cooling shaft, the tube 12 comprises a diffuser 13, which terminates in a chamber of outlet 17. On its lower side, the outlet chamber 17 contains an outlet opening 19 in the plane of the advancing thread. On one side of the outlet chamber 17, an outlet suction line ends in the outlet chamber 17. The expression line 21 is connected to a vacuum generator 20. The vacuum generator 20, which can be designed and constructed , for example, as a pump or blower, generates a vacuum in the outlet chamber 17 and thus, in the tube 12. The lower cooling shaft 7 forms the tension zone 6, which has influence on the friction of yarn in the bundles of filament.

Current below the outlet chamber 17, a thread lubricator 22 and treatment device 23, as well as the receiving device 24 extend in the plane of the advancing thread. As a function of the production process, the treatment device can include, for example, an entanglement nozzle to a suction zone, so that the yarn can be influenced in its tension, and suction, before it is wound up. Similarly, there is the possibility of arranging additional heaters for suction or relaxation within the treatment device. In the apparatus shown in Figure 1, a thermoplastic material advances in a molten state to the rotating head 1. Via the row 2, the material is extruded as filament strands 8 from a plurality of nozzle holes. The receiving device 24 removes the bundle formed by filaments 8. By doing so, the filaments 8 advance at an increasing speed through the cooling zone 4 into the upper cooling shaft 5. Subsequently, the filaments enter, via the condenser 14, the tension zone 6 of the cooling shaft 7. In the tube 12 of the lower cooling shaft 7, the vacuum generator 20 generates a vacuum. Due to the vacuum and due to a self-suction effect generated by the movement of the filaments, a stream of air from the outside is sucked through the air inlet 33 in the cooling zone 4 in the upper cooling shaft. Before entering the cooling zone 4, the air stream is heated to a predetermined temperature by the heater 10. The control of the heater occurs through the controller 11. In this way, the filaments are pre-cooled in the zone of cooling 4 by a refrigerant of a predetermined temperature. After passing through the cooling zone 4, the filaments 8 enter the tension zone 6. In this process, the air entering the cooling zone 4 is carried or admitted. Within the condenser 14, additional cooling air is sucked from the outside through inlets 15.1 and 15.2. The air leaving the cooling zone 4, and the air entering between the inlets 15.1 and 15.2 are accelerated together with a stream of refrigerant in an acceleration zone 16 in the tube 12. In the acceleration zone 16, the flow of air is accelerated due to a narrower cross section in the tube 12 by the action of the vacuum generator 20 in such a way that an air flow acting against the movement of the filaments in the tube is not present any longer . This reduces the stress on the filaments and thus the tension of the yarn. The filaments, which solidify due to thermal crystallization substantially only in their edge regions after they have been subjected to a pre-cooling in the cooling zone 4, will solidify within the tension zone 6 by a stress-induced crystallization. delayed in a desired range, defined within the lower cooling shaft 7. This desired range extends from the acceleration zone 16 to an input area leading to the diffuser 13. In this process, the filaments undergo additional cooling. In order to generate as little turbulence as possible in the outlet area of the lower cooling shaft 7, the air flow is introduced into the outlet chamber 17 via the diffuser 13. To additionally stabilize the air, the outlet chamber 17 contains a sieving cylinder 18, which surrounds the bundle of filaments. Subsequently, the air is removed from the outlet chamber 17 by suction and discharged via the suction line 21 and the vacuum generator 20. The filaments 8 emerge from the underside of the outlet chamber 17 through the outlet opening. 19, and enter the wire lubricator 22. At the moment when the filaments 8 leave the lower cooling shaft 7, they have undergone complete cooling. The wire lubricator 22 combines the elements 8 to a wire 26. After a treatment, the wire 26 is wound with the receiving device 24 to a package 25. The arrangement shown in Figure 1 can be used to produce, for example, a polyester thread, which is wound at a receiving speed greater than 7000 m / min. The apparatus shown in Figure 1 is characterized in that the air entering the cooling zone is heated to a predetermined temperature before centering it. This can be advantageously used to obtain influence on the thermal crystallization within the cooling zone in such a way that the filaments 8 are able to enter the tension zone 6 in a state not yet solidified. The pre-cooling of the filaments is adjusted such that they solidify in a desired, pre-determined range within the tension zone 6. Normally, this desired range is located in the tube 12., or directly current under the acceleration zone 16. With this, it is achieved that the air flow to have influences on the friction of the yarn acts on the filaments before their solidification. As a result of this advantageous treatment of the filaments, the stress-induced crystallization is delayed in such a way as to ensure an increase in the production of the yarn with physical properties, satisfactory, without change. The additionally supplied air on the inlet side of the lower cooling shaft 7 additionally achieves a suitable cooling effect despite a flow oriented parallel in the tension zone. Figures 2-4 illustrate further embodiments of the apparatus according to the invention. In these embodiments, the cooling devices are modified in different ways for purposes of varying both the refrigerant in the cooling zone and the refrigerant current in the zone of tension. The basic construction of the apparatus shown in Figures 2-4 was substantially identical with the apparatus of Figure 1. To this extent, the above description is incorporated herein by reference. Figure 2 illustrates an embodiment of the apparatus according to the invention, wherein the cooling device also comprises a cooling upper shaft 5 and a lower cooling shaft 7. In the cooling zone 4 running below the row 2, the filaments are surrounded by gas permeable wall 9. On the outer side of the wall 9, an air chamber 27 is formed. The air chamber 27 is connected to a blower 28. The blower 28 causes a refrigerant to enter the air chamber 27. The blower 28 is connected to the air chamber 27. a controller 11. On the outlet side of the upper cooling shaft, the lower cooling shaft 7 is connected to it, via a condenser 14. In the condenser 14, a plurality of inlet openings 15.1 and 15.2 are formed, through which is supplied with an air current to the voltage zone. The lower cooling shaft is made cylindrical with the tube 12, which is connected on its inlet side to the condenser 14, and on its outlet side to the diffuser 13. on the outlet side of the lower cooling shaft 7, the tube 12 or diffuser 13 comprises an outlet opening 34, through which the filaments and the cooling stream are able to leave. To generate the cooling current in the tension zone 6, the blower 28 causes the cooling air to enter the upper cooling shaft 5 in the cooling zone 4. In this case, it is preferred to generate an overpressure in the air chamber 27 This causes the refrigerant introduced into the cooling zone to flow into the tension zone 6 and accelerates in the acceleration zone 16 due to the narrow cross section. In this process, an additional air stream is drawn through the inlet openings 15.1 and 15.2. This additional air flow proceeds together with the cooling air blown through the voltage zone 6. However, it is also possible to connect the inputs 15.1 and 15.2 to the blower 28, so that the additional air flow is blown in the tension zone 6. To control the thermal crystallization in the cooling zone 4, the blower 28 is operated at a rotational speed which is predetermined by the controller 11, so that a predetermined amount of air enters the cooling zone for the pre-cooling Figure 3 schematically illustrates a further embodiment, which is substantially identical to the embodiment of Figure 2. To this extent, the above description is incorporated herein by reference, reference being made only to the illustrated differences. In the apparatus shown in Figure 3, a heater 3 is integrated in the air chamber 27 of the upper cooling shaft such that the air entering the cooling zone 4 is preheated to a predetermined temperature. In this connection, the heater 10 and the blower 28 are connected to the controller 11 and are therefore controlled via it. On the outlet side of the upper cooling shaft, a measuring device 29 is arranged such that the outlet air temperature or the filament temperature is measured. The measuring device 29 is connected to the controller 11. The apparatus shown in Figure 3 makes it possible to adjust during the process the location of the solidification zone of the filaments within the tension zone 6. Since both the thermal crystallization and the Voltage-induced crystallization are temperature dependent, it is possible to advantageously use the measurement of the temperature in the transition region of the cooling zone 4 to the tension zone 6 to maintain a predetermined location of the solidification zone. For this purpose the measured temperature is supplied to the controlled 11. In the controller 11, an adjustment occurs between a desired, predetermined value and the actual value, measured. In the case of a control deviation, the control 11 will supply control pulses corresponding to the heater 10, or to the blower 28, or to both units. This apparatus is therefore especially suitable for maintaining a certain level of the solidification zone despite external influences. Figure 4 illustrates a further embodiment of the apparatus according to the invention. This embodiment is designed and constructed essentially in the same manner as the apparatus shown in Figure 1, except that the inlets 15.1 and 15.2 are connected to an annular chamber 30. The annular chamber 30 is connected to a blower 31. With this, it achieves that upstream of the acceleration zone 16, additional cooling air is blown into the tension zone 6. Between the upper cooling shaft 5 and the inlets 15, a second condenser 32 extends in a substantially coaxial relationship with the condenser 14 of the lower cooling shaft 7. As a result, the cooling air leaving the cooling zone 4 is supplied to the pre-accelerated tension zone 6 without significant turbulence. The cooling current formed in the acceleration zone 16 thus consists of the cooling air leaving the cooling zone and the cooling air blown. In the voltage zone 6, the cooling current is generated by the action of the vacuum generator 20 on the output side of the lower cooling shaft 7. The embodiment of the apparatus of the present invention as shown in Figure 4 can also be modified in a simple manner such that the acceleration zone 16 is formed by the first capacitor 14 and directly in the entrance area of the tension zone 6. This construction makes it possible to introduce in the current voltage zone below the acceleration zone, the coolant that is additionally supplied in the lower cooling shaft 7 via the inlets 15. This construction has the advantage that it prevents turbulence in the edge region. of the diffuser as the accelerated coolant extends. In its construction, the apparatus shown in Figures 1 and 4 are examples. In this way, it will be possible to combine the mode shown in Figure 4 with a generation of refrigerant shown in Figure 3. For example, it will be possible to design and build the upper cooling shaft as a so-called cooling system operating with a flow of transverse air where the cooling air hits the bundle of filaments from only one side. Likewise, it is possible to construct the lower cooling shaft in the form of a frame to receive a plurality of wires. In this case, the side walls of the lower cooling shaft shown in Figure 1 will be extended perpendicular to the plane of the drawing.

Claims (23)

1. A process for melt spinning a multi-filament yarn comprising the steps of: extruding a polymer melt, heated through a spinneret to test a plurality of downwardly advancing filaments that are initially in the liquid form, cooling the filaments by contact with a refrigerant which is introduced into a cooling zone which is located downstream of the spinneret, in such a way that the filaments do not solidify within the cooling zone, additionally cooling the filaments in a zone of tension located downstream of the cooling zone by contact with a cooling stream in such a way that the filaments solidify within the tension zone, and control in an adjustable manner the cooling of the filaments within the cooling zone in such a way that the location of the solidification of the filaments within the tension zone is kept within an desired, predetermined.

2. The process according to claim 1, wherein the step of controlling in an adjustable manner the cooling of the filaments includes varying the temperature of the refrigerant before entering the cooling zone.

The process according to claim 1, wherein the step of controlling in an adjustable manner the cooling of the filaments includes varying the flow volume of the refrigerant before it enters the cooling zone.

The process according to claim 1, wherein the refrigerant stream accelerates in an acceleration zone within the tension zone, and wherein the location of the solidification of the filaments within the tension zone is maintained in or is immediately current under the acceleration.

The process according to claim 1, wherein the refrigerant is introduced into the cooling zone and then caused to advance in the tension zone to form at least a portion of the refrigerant stream.

The process according to claim 5, wherein the refrigerant stream is formed from the refrigerant leaving the cooling zone and from a refrigerant supplied directly at an end portion upstream of the tension zone.

The process according to claim 5, wherein the cooling current is generated in the tension zone by a suction effect.

The process according to claim 1, wherein the cooling current is generated in the tension zone by a blowing effect.

The process according to claim 1, wherein the tension zone is formed by a conduit through which the filaments advance, with the conduit comprising adjacent to its upstream end, a narrow cross-section that operates as an area of acceleration.

The process according to claim 1, wherein the refrigerant is introduced into the cooling zone by a suction effect or by a blowing effect.

The process according to claim 1, comprising the further, additional steps of collecting the advance filaments to form a multi-filament advance yarn, and then winding the yarn into a bundle.

The process according to claim 1, wherein the polymer melt is selected from the group consisting of polyester, polyamide and polypropylene.

A melt spinning apparatus for producing a multi-filament yarn, comprising: an extruder for heating a polymeric material and extruding the resulting melt through a spinneret to form a plurality of filaments advancing downward which initially they are in the liquid form. the cooling device placed below the die to employ the advance filaments and comprising a cooling upper shaft defining a cooling zone and having a gas permeable side wall, and a lower cooling shaft defining a zone of tension placed below the upper cooling shaft, at least one cooling current generator for causing a refrigerant to enter the upper cooling shaft through the air permeable side wall and to cause a cooling current directed in the direction of the advancing filaments to flow through the lower shaft of cooling, and the means for adjusting the cooling for the filaments in the upper cooling shaft so that the location of the zone to which the filaments solidify and maintain within a desired range, predetermined in the lower cooling shaft.

The melt spinning apparatus according to claim 13, wherein the means for adjusting the cooling of the filaments comprises a heater placed to heat the refrigerant before entering the upper cooling shaft.

15. The melt spinning apparatus according to claim 13, wherein the means for adjusting the cooling of the filaments comprises a blower that is capable of varying the volumetric flow of the refrigerant before entering the upper cooling shaft.

The melt spinning apparatus according to claim 13, wherein the lower cooling shaft includes an acceleration zone defined by a narrow cross-section for the purpose of accelerating the cooling current, with the acceleration zone which is placed current above the desired range, predetermined to solidify the filaments.

17. The melt spinning apparatus according to claim 13, wherein the upper cooling shaft is directly connected to the lower cooling shaft, and wherein the lower cooling shaft includes a coolant inlet located immediately below the upper shaft. Cooling.

18. The melt spinning apparatus according to claim 17, wherein the cooling current generator comprises a blower for blowing coolant into the lower cooling shaft via the inlet.

19. The melt spinning apparatus according to claim 13, wherein the cooling current generator is a vacuum generator that is connected to a downstream portion of the lower cooling shaft to withdraw coolant to the lower cooling shaft.

20. The melt spinning apparatus according to claim 13, wherein the lower cooling shaft comprises a tube having at its inlet end a condenser and at its outlet end a diffuser, with the condenser and diffuser which are connected in its cross sections, narrower.

21. The melt spinning apparatus according to claim 20, wherein the lower cooling shaft further comprises a second condenser located between the upper cooling shaft and said first condenser, and a refrigerant inlet arranged between the two condensers.

22. The melt spinning apparatus according to claim 13, wherein further comprising a guiding means for collecting the advance filaments to form a multi-filament advance yarn, and a bobbin winder for winding the advance yarn in a packet .

23. The melt spinning apparatus according to claim 22, wherein the guiding means is positioned adjacent a downstream end of the lower cooling shaft.