Title of Invention

APPARATUS FOR MELT SPINNING, COOLING AND WINDING

Abstract

An apparatus for melt spinning, cooling, and winding a yarn formed from a plurality of filament strands, with a spin unit, which comprises a spinneret for extruding an annular group of filaments, with a cooling unit downstream of the spin unit for cooling the filament strands that form the group of filaments, and with a takeup unit for winding the yam that is formed after cooling the filament strands, with the cooling unit comprising an air diffuser that is held in an operating position substantially in centric relationship with the spinneret, and which comprises a porous air-permeable jacket for generating a predominantly turbulent cooling air stream flowing from the inside outward, characterized in that an additional jacket encasing I the air-permeable jacket of the air diffuser is provided, and that the additional jacket consists of a material with a plurality of openings, which leads without a significant flow resistance to an orientation of the cooling air stream predominantly without turbulences.

Full Text

The invention relates to an apparatus for melt spinning, cooling, and winding a yam formed from group of filaments as well as an apparatus for cooling a group of filaments. In the melt spinning of synthetic filament yams, the cooling of freshly extmded filament strands is of special importance for the later quality of the synthetic yam formed from the filament strands. In particular in the production of textile yams, very fine filament sfrands are extruded, which react very sensitively to a cooling by a cooling air stream, and thus need a particularly uniform cooling. For cooling melt spun filament strands, one basically distinguishes between two cooling methods. In a first variant, a cooling air stream is directed from the outside to a filament bundle. In such systems, one has to see in particular that the filament strands advancing in the interior receive an adequate cooling. In a second variant, the filament strands are spun in an annular arrangement, and in the center of the annular filament arrangement a cooling air stream is generated that is directed from the inside outward. The invention is based on this principle. To generate the cooling air stream that penetrates the filament sheet from the inside outward, so-called air diffusers are used, as are disclosed, for example, in DE 196 53 451 Al. The air diffuser is made cylindrical and possesses a porous, gas-permeable jacket. At its one end, the air diffuser is closed, and at its opposite end, it connects to an air supply, which introduces a cooling air into the interior of the air diffuser. To obtain a cooling air that emerges from all over the air-permeable jacket with a preferably predetermined blow profile, the jacket consists of a porous material with a certain flow resistance. Thus, it is known to produce the air-permeable jacket of the air diffuser of sintered metal, metal foam, foam material, or wound paper layers. As a result of the pores and openings that are contained in the materials in an irregular pattern, a flow is generated, when the cooling air emerges from the air-permeable jacket. This flow is often not adequately laminar and not uniform when viewed over the entire surface. However, such flow profiles lead to irregularities in the cooling of fine filament strands, in addition, they have a negative influence on the smooth advance of the filament strands. Furthermore, the conventional air diffusers comprise a jacket with little permeability, and thus require great pressure differences for obtaining an outflow over the entire surface of the air diffuser. This, however, is bound to lead to irregularities because of preferred outflow regions, which also include turbulences. An increase of the gas-permeability in the porous jacket is then again not possible, since the effect of the irregularity of the cooling air exiting in the region of the air diffuser further increases. Moreover, it is disclosed in DE 37 08 868 A1 or US 4,285,646 to provide in the interior of the air diffuser guide means for influencing the cooling airflow leaving through the air-permeable jacket. These guide means are preferably used for realizing certain blow profiles on the air diffuser. However, they are unable to influence the outflow that is characteristic of the porous stmcture of the air- permeable jacket. It is therefore an object of the invention to provide an apparatus for producing melt spun yams of the described type, which permits producing textile yams with a high uniformity, in particular with respect to Uster evenness values, elongation, and strength. It is a further object of the invention to further develop an apparatus for melt spinning and cooling as well as an apparatus for cooling of the type as has been initially described, in such a manner that a uniformly generated coolmg air stream prevails over the entire cooling zone for cooling the group of filaments. Advantageous further developments are defined by the features and feature combinations of the dependent claims. The invention is characterized in that before impacting upon the filament strands, the cooling air exiting from the air diffuser is converted into a laminar flow in a predetermined direction. With that, it is possible to generate a movement of the cooling air that is suitable for cooling strands of fine filaments, and which leads to a uniform formation and solidification of the individual filament strands. in so doing, it is possible and advantageous to prevent irregularities in the evenness from filament to filament and in the evenness of the yam over the time. The additional jacket that is provided for equalizing and orienting the cooling airflow is of a material with a plurality of openings, which essentially causes no additional flow resistance. This has no significant influence on the blow characteristic of the air-permeable jacket that is enclosed by the additional jacket, and the cooling air leaving the air-permeable jacket as a turbulent flow undergoes only a conversion into a laminar flow. To obtain a uniform penetration of the filament sheet, the further development of the invention has been found especially satisfactory, wherein the material of the additional jacket has largely radially oriented openings for generating a cooling air stream that is transversely directed to the filament strands. In this process, a laminar flow of the cooling air that exits from the surface of the additional jacket is generated substantially at a right angle. However, it is also possible to produce over the length of the air diffuser different orientations of the cooling air for purposes of obtaining special precooling and aftercooling effects by a cooling air stream that is inclined against the direction of the advancing yarn, or a cooling air stream that is inclined in the direction of the advancing yam. Very advantageously suited as material for the additional jacket is a multilayer wire fabric with a high, open flow surface. In this instance, the flow resistances are negligible. However, it is also possible to use perforated or honeycomb sheet metal elements, which are preferably seamless. A preferred further development of the invention provides for arranging the additional jacket in abutting contact with the air-permeable jacket and for holding it by the air diffuser. This development has the advantage that the additional jacket produces on the air-permeable jacket a supporting effect, so that the air-permeable jacket can be made of paper or foam material of little strength. In this connection, it is possible and advantageous to join the air-permeable jacket and the additional jacket to one structural unit, which simplifies the handling of the air diffuser considerably. However, it is also possible to arrange the additional jacket in spaced relationship with the air diffuser. In this case, the additional jacket is arranged on a holding device that mounts the air diffuser. This further development of the invention has the advantage that is permits using the entire surface of the air-permeable jacket for generating the cooling air stream. In addition, it is possible to arrange the additional jacket on the holding device in an exchangeable manner, so that when a yarn denier or a polymer is changed, it becomes possible to make a corresponding adaptation of the cooling by exchanging the additional jacket. To prevent in the case of exchangeable additional jackets, axial flows from forming in the annular space formed between the air-permeable jacket and the additional jacket, the additional jacket is held by the holding device in an operating position at the free end of the air diffuser via a spacer against a stop on the spinning unit. With that, the additional jacket is safely sealed at its ends between the spacer and the holding device. For purposes of maintenance or for cleaning the spinneret, the holding device is advantageously used to move the air diffuser with the additional jacket out of the operating position, away from the spin unit, to a standby position. To this end, the holding device is constructed for vertical adjustment and/or pivotal movement relative to the spinning unit. To obtain a safe advance of the filament strands along the air diffuser, a preferred further development of the invention provides for equipping the holding device below the air diffuser with a yam lubrication device, which includes a lubrication ring that is contacted by the group of filaments. It is thus possible to lubricate the entire group of filaments uniformly before combining them to a synthetic yam. To combine the group of filaments, it is preferred Co use a collection yam guide downstream of the yarn lubrication device. Depending on the yarn being produced, one or more treatment devices may be provided upstream of the takeup unit. It is thus possible to produce partially oriented POY yarns or fully drawn FDY yams, which consist of a meltable synthetic polymer, such as, for example, polyester, polyamide, or polypropylene. This basically permits producing textile or industrial yarns. The invention also extends to such methods, wherein a group of annularly advancing filaments is to be cooled while maintaining high evenness values, such as, for example, in the production of staple fibers. In this process, it is possible and advantageous to use the apparatus of the invention according to claim 14 for cooling the filament strands, before combining them to a tow. Besides the advantageous further developments according to claims 15 and 16, the apparatus of the invention according to claim 14 may also be further developed by the aforesaid features and feature combinations of claims 4-13. In the following the apparatus of the invention is described in greater detail based on some embodiments with reference to the attached drawings, in which: Figure 1 is a schematic view of a first embodiment of the apparatus according to the invention; Figure 2 is a schematic view of a further embodiment of an apparatus according to the invention; and Figure 3 is a schematic cutout view of the jacket of the air diffuser as used in the embodiment of Figure 2. Figure 1 schematically illustrates a first embodiment of an apparatus according to the invention for melt spinning, cooling, and winding a synthetic yarn. The apparatus comprises a spinning unit 1, a cooling unit 6 downstream of the spinning unit 1, and a takeup unit 19 downstream of the cooling unit 6. The spinning unit 1 accommodates a heated spin head 2, which mounts on its underside a spinneret 3. On its underside, the spinneret 3 has an annular arrangement of a plurality of spin holes for extruding a plurality of filament strands. The spin head 2 accommodates additional melt guiding and melt advancing components not shown in the drawing. For example, a puinp not shown delivers to the spinneret 3 a polymer melt that advances via a melt supply line 4, Typically, the spin head 2 accommodates a plurality of spinnerets 3 for producing a plurality of yams parallel in side-by-side relationship. Since the invention can easily be extended to two, three, or more yams, the drawing shows, for the sake of clarity, the arrangement for producing only one yam. Downstream of the spin unit 1 is a cooling unit 6. The cooling unit 6 comprises an air diffuser 7, which is arranged on a holding device 10. The air diffuser 7 is made hollow-cylindrical and comprises an air-permeable jacket 8 that is made of a porous material. The material of the air-permeable jacket 8 can be formed by wound paper layers, foam material, or sintered metal. At the free end of the air diffuser 7, the jacket 8 is closed by an end piece 15. With its opposite end, the jacket 8 is arranged on the holding device 10. In spaced relationship with the jacket 8, the holding device 10 mounts an additional jacket 9, which encases the air-permeable jacket 8. The air diffuser 7 and the additional jacket 9 are arranged via a spacer 14 on the underside of the spin head 2 in centric relationship with the spinneret 3. The spacer 14 is held at the end of the air diffuser 7 by the holding device 10 against a stop 22 on the underside of the spin head 2. In their operating position, both the additional jacket 9 and the air diffuser 7 held in the interior of the additional jacket are located in centric relationship with the spinneret 3. For positioning the air diffuser 7 and the additional jacket 9, the holding device 10 is made vertically adjustable and pivotal. To guide a cooling air into the interior of the air diffuser 7, the holding device 10 connects to an air supply line 11. The air supply line 11 in turn connects to a coolant source not shown, for example, a blower. Inside the holding device 10, the air supply line 11 connects via a channel system to the open end of the air-permeable jacket 8 in the holding device 10. On the periphery of the holding device 10, a yarn lubrication device 12 extends. In the present embodiment, the yarn lubrication device 12 is formed by a lubrication ring 13, which contains a lubricant that emerges on its surface, and which wets the filament strands 5 advancing over the periphery of the lubrication ring 13. Downstream of the cooling unit 6 is a collection yam guide 17, which combines the filament strands 5 to a yam 16. For withdrawing the filament strands 5 or the yarn 16, a treatment device 18 is provided. The treatment device 18 is symbolically shown, since it differs in its construction and composition of the units as a function of the yarn type being produced. For example, it may comprise one or more godets or godet units for withdrawing, guiding, or drawing the yarn. Furthermore, it is possible to integrate entanglement devices, additional yarn lubricators, or yarn cutters with suction systems or yam sensors. In the alternative, the yam 16 or the filament strands 5 could also be withdrawn by the takeup unit 19. For receiving the yarns, the takeup unit 19 is provided downstream of the treatment device 18. The takeup unit 19 is symbolically shown by the illustration of a package 20 and a contact roll 21 lying against the circumference of the package 20. In this arrangement, the yam 16 is wound to the package 20. In the embodiment of the apparatus according to invention as shown in Figure 1, a molten polymer material is supplied to the spin unit 1, for example, by an extruder or pump. To this end, the polymer melt enters the spin head 2 via the heated melt supply line 4 and advances under pressure to the spinneret 3. The spinneret 3 is made circular and includes on its underside one or more annular rows of spin holes, from which the polymer melt emerges as fine filament strands 5. After extruding the filament strands 5 through the spinneret 3, the filament strands 5 advance through the cooling unit 6 downstream of the spin unit 1. /For cooling the annularly advancing filament strands 5,"a cooling air is supplied via the air supply line 11, which enters the interior of the air diffuser 7 under an admission pressure. Based on the admission pressure, a cooling air stream forms that radially penetrates the jacket 8 of the air diffuser 7. The flow developing on the circumference of the air-permeable jacket 8 is substantially defined by the pore distribution of the material of jacket 8. The cooling airflow exiting from the air-permeable jacket 6 of the air diffuser 7 ia predominantly turbulent. The material used for forming the air-permeable jacket 8 could be multilayered paper, or foam material, or sintered metal. The cooling airflow leaving the air-permeable jacket 8 then advances through the additional jacket 9. The additional jacket 9 consists of a material with a plurality of openings, which present on the one hand very little flow resistance to the cooling airflow, and lead on the other hand to an orientation of the cooling airflow. To this end, the material includes preferably radially oriented openings, so that a transversely directed laminar flow develops on the additional jacket 9 over the entire cooling length. This airflow penetrates the sheet of filaments for cooling the filament strands 5. The equalization of the cooling airflow by the additional jacket 9 causes air to be uniformly directed to the filament strands without turbulences. This results in a very smooth advance, which affects in particular the Uster evenness of the filament and thus in the yam. The laminar flow produced by the additional jacket 9 for cooling the filament strands is also maintained when the admission pressure of the cooling air inside the air diffuser is changed for increasing the amount of the cooling air. At the end of the cooling zone, the filament strands 5 advance over the circumference of the holding device 10 in contact with the lubrication ring 13 or yarn liibrication device 12. After having been lubricated, the filament strands 5 are combined to the yarn 16, which is wound after a treatment to a package 20. The apparatus of the invention as shown in Figure 1 is especially suited for producing textile yarns. In this process, it is possible to produce both POY yarns with a partial drawing, and FDY yarns with a full drawing. To be able to make an adaptation to the yarn type being produced also with respect to cooling, the additional jacket 9 is exchangeably connected to the holding device 10 in the embodiment of the apparatus of the invention shown in Figure 1. The holding device 10 is movable, so that the air diffuser 7 can be moved with the additional jacket 9 from its operating position to a standby position. in the standby position, it is possible to exchange the additional jacket 9. With that, one can vary, for example, the geometries or arrangements of holes in the additional jacket 9 by choosing a certain material or a certain shape. Figure 2 illustrates a further embodiment of the apparatus according to the invention. The embodiment is essentially identical with the foregoing embodiment shown in Figure 1, so that only differences will be described, otherwise, the foregoing description is herewith incorporated by reference. In the embodiment shown in Figure 2, the cooling unit 6 downstream of the spin unit 1 is formed by an air diffuser 7 for generating a radially directed cooling aiV stream. In this case, an additional jacket 9 is slipped over the air diffuser 7 in direct contact with the air-permeable jacket 8. The air-permeable jacket 8 and additional jacket 9 form one structural unit, which is held at its free end by a common end piece 15. With their opposite end, the air-permeable jacket 8 and the additional jacket 9 are moimted to the holding device 10, with the air-permeable jacket 8 having an open end for receiving cooling air. The function of the additional jacket 9 and the air-permeable jacket 8 as well as the construction of the additional jacket 9 and the air-permeable jacket 8 are largely identical with the foregoing embodiment, so that also with respect to the function, the foregoing description is herewith incorporated by reference. In the embodiment shown in Figure 2, the additional jacket 9 directly supports the air-permeable jacket 8. Consequently, it is possible to make the air-permeable jacket 8 less strong, for example, to construct it from a foam material or thin paper layers. To he able to use the resistance characteristic of the air-permeable jacket 8 largely unchanged for generating a cooling air stream, the additional jacket 9 is of a material which has a negligible flow resistance in comparison with the material of the air-permeable jacket 8. To this end, Figure 3 shows an embodiment of a construction of the air-permeable jacket 8 and additional jacket 9. The air-permeable jacket 8 is formed of a foam material. The outer circumference of the air-permeable jacket 8 mounts the additional jacket 9. The additional jacket 9 is formed by a multilayer wire fabric 23. The multilayer wire fabric 23 forms largely radially oriented openings 24, which lead to an equalization of the cooling airflow exiting from the air-permeable jacket 8. On the circumference of the additional jacket 9, a transversely directed, laminar cooling airflow emerges for penetrating the filament strands that surround the additional jacket 9. The setup of the spin unit and the cooling unit shown with respect to the embodiments of Figures 1 and 2 is exemplary. For example, it is also possible to supply cooling air via the spin head. It is likewise possible to replace the yarn lubrication device on the circumference of the holding device with a yarn guide ring. In this case, a yarn lubrication device would be associated to the collection yarn guide. Likewise, the construction and the length ratio of the spacer to the length of the air diffuser are exemplary. Basically, the length of the spacer permits forming a guiet zone, in which the filaments undergo no active cooling. In such a zone, it would also be possible to arrange, for example, afterheaters for influencing the molecule orientation of the filament strands. In addition, the invention also extends to such methods, wherein the filament strands are combined after their cooling to tows for producing staple fibers. To this end, one may use cooling devices, which are in their construction identical with the embodiments of Figures 1 and 2. For describing such devices, one may incorporate the foregoing descriptions by reference. HOHENCLATURE 1 Spin unit 2 Spin head 3 Spin beam 4 Melt supply line 5 Filament strand 6 Cooling unit 7 Air diffuser 8 Air-permeable jacket 9 Additional jacket 10 Holding device 11 Air supply line 12 Lubrication device 13 Lubrication ring 14 Spacer 15 End piece 16 Yarn 17 Collection yarn guide 18 Treatment device 19 Takeup unit 20 Package 21 Contact roll 22 Stop 23 Wire fabric 2 4 Openings WE CLAIM: 1. An apparatus for melt spinning, cooling, and winding a yam (16) formed from a plurality of filament strands (5), with a spin unit (1), which comprises a spinneret (3) for extruding an annular group of filaments (5), with a cool unit (6) downstream of the spin unit (1) for cooling the filament strands (5) that form the group of filaments, and with a makeup unit (19) for winding the yam (16) that is fired after cooling the filament strands (5), with the cooling unit (6) comprising an air diffuser (7) that is held in an operating position substantially in centric relationship with the spinneret (3), and which comprises a porous air-permeable jacket (8) for generating a predominantly turbulent cooling air stream flowing the inside outward, characterized m that an additional jacket (9) encasing the air-permeable jacket (8) of the air diffuser (7) is provided, and that the additional jacket (9) consists of a material with a plurality of openings (24), which leads without a significant fow resistance to an orientation of the cooling air stream predominantly without turbulences. 2. The apparatus as claimed in claim 1, wherein the material of the additional jacket (9) comprises radially oriented openings (24), for generating a cooling air stream that is transversely directed to the filament strands (5). 3. The apparatus as claimed in claim 1 or 2, wherein the material is preferably formed from a multilayer wire fabric (23) 4. The apparatus as claimed in any one of claims 1-3, wherein the additional jacket (9) lies against the air-permeable jacket (8) in contacting relationship therewith, and is held by the air diffiiser (7). 5. The apparatus as claimed in claim 3, wherein the air-permeable jacket (8) and the additional jacket (9) are joined to one structural unit. 6. The apparatus as claimed in any one of claims 1-3, wherein the additional jacket (9) is arranged in spaced relationship with the air-permeable jacket (8), and held by a holding device (10) that mounts the air difhxser (7) 7. The apparatus as claimed in claim 6, wherein the additional jacket (9) is exchangeably arranged on the holding device (10). 8. The apparatus as claimed in claim 6 or 7, wherein the additional jacket (9) lies in the operating position at the free end of the air difiijser against a spacer (14), which supports the air diffiiser (7) relative the spin unit (1). 9. The apparatus as claimed in any one of claims 1-8, wherein the additional jacket (9) is adapted for being moved with the ah- diffuser (7) by the holding device (10) from the operating position, away from the spin unit (1), to a standby position. 10. The apparatus as claimed in any one of the foregoing claims, wherein in that the holding device (10) mounts downstream of the air diffuser (7) a yam lubrication device (12), which comprises a lubrication ring (13) that is contacted by the filament strands (5) U. The apparatus as claimed in claim 10, wherein the lubrication ring (13) is followed by a collection yam guide (17), which combines the filament strands (5) to a synthetic yam (16). 12. The apparatus as claimed in any one of claims 1-U, wherein the holding device (10) is made pivotal relative to the spin unit (1). 13. The apparatus as claimed in any one of the foregoing claims, wherein one or more treatment devices (] 8) are provided, which precede the takeup unit (19). 14. A cooling unit for cooling a group of fieshly extruded filaments, with an air diffuser (7), which is arranged in centric relationship with the annularly advancing filament strands (5) of the group of filaments, and which comprises a porous air-permeable jacket (8) for generating a predominantly turbulent cooling air stream that flows from the inside outward, characterized in that an additional jacket (9) is provided that encases the air-permeable jacket (8) of the air diffuser (7), and that the additional jacket (9) consists of a material with a plurality of openings (24), which leads without any significant flow resistance to an orientation of the cooling air stream predominantly without turbulences. 15. The cooling unit as claimed in claim 14, wherein the material of the additional jacket (9) comprises radially oriented openings (24) for generating a cooling air stream that is transversely directed to the filament strands (5). 16. The cooling unit as claimed in claim 14 or 15, wherein the material is formed of a multilayer wire fabric (23)

Documents:

0174-chenp-2006 abstract-duplicate.pdf

0174-chenp-2006 abstract.pdf

0174-chenp-2006 claims-duplicate.pdf

0174-chenp-2006 claims.pdf

0174-chenp-2006 description (complete)-duplicate.pdf

0174-chenp-2006 description (complete).pdf

0174-chenp-2006 drawings-duplicate.pdf

0174-chenp-2006 drawings.pdf

0174-chenp-2006 form-1.pdf

0174-chenp-2006 form-18.pdf

0174-chenp-2006 form-26.pdf

0174-chenp-2006 form-3.pdf

0174-chenp-2006 form-5.pdf

0174-chenp-2006 pct.pdf

0174-chenp-2006-correspondnece-others.pdf

0174-chenp-2006-correspondnece-po.pdf

0174-chenp-2006-others.pdf

0174-chenp-2006-pct.pdf