Title of Invention

APPARATUS FOR SPINNING A SYNTHETIC YARN

Abstract

An apparatus for spinning a synthetic yarn, which is formed by combining a filament bundle consisting of a plurality of individual filaments and which is wound to a package by a takeup device downstream of the spinning apparatus, the apparatus comprising a spinneret; a cooling tube extending at a distance from spinneret downstream thereof, the cooling tube comprising an inlet with a narrowest cross section in cooling tube, a cylindrical portion connected to the inlet, and an outlet; a . gas-permeable inlet cylinder arranged between spinneret and inlet of cooling tube; a suction device that connects to the outlet of cooling tube such that it generates an air stream in cooling tube in direction of the advancing yarn; and an air supply device for generating an additional cooling air stream in axial direction of the cooling tube for cooling filaments, characterized in that the air supply device is formed in direction of the advancing yarn downstream of the inlet in the region of the cooling tube or downstream of the outlet of the cooling tube.

Full Text

The invention relates to an apparatus for spiiming a synthetic yam as well as a method of spinning a synthetic yam. This spinning apparatus and method are known from EP 0 682 720. In the known spinning apparatus, freshly extmded filaments advance in a cooling tube with a vacuum atmosphere. The cooling tube is arranged at a distance from the spinneret, so that an air stream develops in the cooling tube for cooling the filaments in direction of the advancing yam. In this connection, the flow velocity of the air and the spinning speed are adapted to each other such that the air stream assists the filaments in their advance in the cooling tube. With that, it is accomplished that the solidification point of the filaments moves away from the spinneret. This is accompanied by a delayed crystallization of the polymer that favorably influence the physical properties of the yam. Thus, for example, in the production of POY yam, it was possible to increase the withdrawal speed and, thus, the draw ratio, without changing for the yam the elongation values necessary for fiirther processing. The known spinning apparatus consists of a cooling tube and a suction device downstream of the spinneret. Between the spirmeret and the cooling tube, an inlet cylinder extends with a gas permeable wall. By the interaction of the inlet cylinder and the suction device, a quantity of air is introduced within the spin shaft and guided within the cooling tube as an accelerated air stream in the direction of the advancing yam. As the filaments pass through the inlet cylinder, they are precooled in such a manner that an increase of viscosity in the surface layers causes the firmness of the surface layer to increase. Upon their entry into the cooling tube, the filaments are still molten in their core, so that final solidification occurs only in the cooling tube. To this end, the cooling tube consists of a funnel-shaped inlet with a narrowest cross section in the cooling tube and cylindrical portion directly adjacent thereto. The narrowest cross section and the cylindrical portion cause the air stream to accelerate such that the filaments are assisted in their advance and undergo a delayed solidification only in the cooling tube. However, in the case of coarser filament deniers, the problem arises that while the air stream entering the cooling tube assists the advance of the filaments, it will not lead to an adequate cooling of the filaments. Although the known spinning apparatus is provided with an air supply device at the inlet end of the cooling tube for generating an additional cooling stream, same leads, however, to a considerable cooling of the filaments already before the air stream is accelerated in the cooling tube, so that the positive effect of a delayed crystallization of the polymer is not effective or only inadequately effective. The US 5,173,310 describes a spinning apparatus comprising cooling device located below a spinneret with an upstream and a downstream region. In each region a cooling chimney is formed with a gas permeable, inner wall that encloses the filaments. The upper and the lower cooling chimney are each connected to fan means for supplying cool air, so that a cooling air stream is formed originating from the gas permeable wall flowing transverse the direction of the advancing yam. This air stream necessarily leads to a considerable yam friction, whereby the movement of the filaments is unfavorably affected. It is therefore the object of the invention to improve the initially described spinning apparatus and method such that filaments with coarser deniers are adequately cooled over a short distance, even in the case of delayed crystallization of the polymer, and at high spinning speeds. The invention has the advantage that the air stream present at the inlet end of the cooling tube serves to delay exclusively crystallization of the polymer. This ensures that the solidification point of the filaments is inside the cooling tube. For further cooling the filaments, use is made of the cooling air stream that is introduced by an air supply device. To this end, this air supply device is arranged downstream of the narrowest cross section of the inlet in the cylindrical portion or downstream of the outlet end of the cooling tube. With that, it is accomplished that the cooling air stream contacts the filament bundle only shortly before or after solidification of the filaments. This influences in particular the evenness of the filament cross sections and results in a high spinning reliability and absence of lint. The especially preferred further development of the spinning apparatus has the advantage that the cooling air stream enters the cooling tube substantially uniformly. Since the air stream and the cooling air stream are equidirectional, turbulences are essentially avoided. In this connection, it is possible to construct the air supply device in a simple manner by an opening in the wall of the cooling tube. The cooling stream entering the cooling tube through the opening adjusts itself automatically due to the vacuum atmosphere in the cooling tube. The further development of the invention distinguishes itself in that the air stream entering at the inlet end of the cooling tube and the cooling air stream entering the cooling tube through the opening are adjustable independently of each other. To this end, the air supply device comprises an air stream generator that generates the cooling air stream. The air stream generator could be, for example, a blower. In a particularly advantageous further development of the spinning apparatus, the air stream generator is constructed as an injector with a nozzle bore that connects to a source of compressed air. In this arrangement, the nozzle bore of the injector terminates directly in the opening in the wall of the cooling tube. In this connection, the center axis of the cooling tube and the nozzle bore form an acute angle in direction of the advancing yam, so as to introduce into the cooling tube the cooling air stream with an orientation in direction of the advancing yam. Such a configuration of the spinning apparatus is also suitable in particular for threading the filaments into the cooling tube at the start of the process. An angle range from 15°C to 30°C further accomplishes that in the region of the cooling air stream the filament bundle is safely kept off the wall of the cooling tube. To adjust the cooling air stream as a function of the filament type and filament denier, the embodiment of the spinning apparatus is especially advantageous. A means to use for adjusting the free flow cross section of the opening may be a sleeve mounted on the cooling tube, which is arranged for movement along the cooling tube for closing the opening in full or in part. In an advantageous further development, the adjustment means consists of an air chamber enclosing the opening in the cooling tube from the outside. This air chamber comprises a supply line with a throttling device. Thus, it is possible to control the air supply to the air chamber by means of the throttling device in the supply line. To realize with the cooling stream a most intensive possible cooling, it is possible to connect, the supply line of the air chamber to the air stream generator. In the embodiments, the opening arranged in the wall of the cooling tube may be made as a bore or a radial cutout. In a particularly advantageous further development of the spinning apparatus, the opening is formed by an annular, perforated sheet element in the wall of the cooling tube. In this instance, the perforated sheet element extends over the entire surface of the cooling tube. This ensures a uniform inflow of the cooling air stream into the cooling tube. The plurality of holes permits to generate a flow that is affected by little turbulence. In a particularly preferred further development of the invention, the perforated sheet element is made conical with a cross section increasing in direction of the advancing yam and arranged in the extension of the cooling tube at the outlet end thereof With that, cooling of the filaments is further intensified since the expansion of the air stream effects a better mixing between the cooling air stream and the air stream. Besides a very intensive cooling, the particularly advantageous further development facilitates a preliminary drawing of the filaments. The cooling air stream oppositely directed to the direction of the advancing yam generates on the filaments a frictional force that acts against the direction of the advancing yam. This frictional force effects a drawing of the filaments. In the embodiment of the spinning apparatus, the air supply device is constmcted such that the suction device can generate the cooling air stream. To this end, a second cooling tube connects as an extension to the first cooling tube directly to the outlet chamber of the suction device. To equalize the flow, it is preferred to construct the second cooling tube with a funnel-shaped inlet and a cylindrical outlet with an air-permeable wall. To increase the draw effect in the case of such an air supply device, the cooling tube could comprise a heating device. The method of the present invention is characterized in particular in that it permits production of textile or industrial yarns of polyester, polyamide, or polypropylene with coarse deniers and high elongation values. The method may be coupled with different treatment devices, so that, for example, fully drawn yarns, partially oriented yarns, or highly oriented yarn can be produced. In the following, some embodiments of the spinning apparatus according to the invention are described in more detail with reference to the drawing. In the drawing: Figure 1 illustrates a first embodiment of a spinning apparatus according to the invention with a takeup device downstream thereof; Figure 2 illustrates a further embodiment of a spinning apparatus according to the invention with an air supply device arranged on the cooling tube; Figure 3 illustrates a further embodiment of an air supply device; and Figures 4 and 5 illustrate further embodiments of the spinning apparatus according to the invention with an air supply device. Figure 1 shows a first embodiment of a spinning apparatus according to the invention for spinning a synthetic yarn. A yarn 12 is spun from a thermoplastic material. To this end, an extruder or a pump melts the thermoplastic material. A spin pump delivers the melt via a melt line 3 to a heated spin head 1. The underside of spin head 1 mounts a spinneret 2. From the spinneret 2, the melt emerges in the form of fine filament strands TL1U1/436H964M 5. The filaments 5 advance as a filament bundle through a spin shaft 6 that is formed by an inlet cylinder 4. To this end, the inlet cylinder 4 extends directly downstream of spin head 1 and surrounds the filaments 5. In direction of the advancing yarn, a cooling tube 8 connects to the free end of inlet cylinder 4. At the inlet end of the filaments, the cooling tube 8 comprises an inlet 9. The inlet 9 that is preferably funnel-shaped connects to the inlet cylinder 4. In the narrowest cross section of inlet 9, the cooling tube 8 comprises a second, cylindrical portion 32. At the end of cylindrical portion 32, the cooling tube 8 comprises an outlet cone 10 that forms an outlet 33. The outlet cone 10 terminates in an outlet chamber 11. On its underside, the outlet chamber 11 mounts an air supply device 34. The air supply device 34 consists of a further cooling tube 35. From the underside of outlet chamber 11, the second cooling tube 35 extends coaxial with the first cooling tube 8. At its inlet end, the second cooling tube 35 comprises a funnel-shaped inlet 36 that connects to the outlet chamber 11. The free end of the second cooling tube 35 forms a cylindrical outlet 37 with a gas- permeable wall. The outlet comprises at its front end an outlet opening 13, from which the filaments 5 emerge. A suction stub 14 terminates in suction chamber 11 on one side thereof. Via suction stub 14, a suction device 15 arranged at the free end of suction stub 14 connects to outlet chamber 11. The suction device 15 may comprise, for example, a vacuum pump or a blower that generates a vacuum in outlet chamber 11 and, thus, in the first cooling tube 8 and in the second cooling tube 35. Between the outlet 33 of the first cooling tube and the inlet 36 of the second cooling tube 35, the outlet chamber 11 accommodates a screen cylinder 30" that surrounds the filaments 5. The screen cylinder 30 has an air-permeable wall. In the plane of the advancing yarn downstream of the air supply device 34, a lubrication device 16 and a takeup device 20 are arranged. The takeup device 20 includes a yarn guide 19. The yarn guide 19 indicates the start of a traversing triangle that results from the reciprocal movement of a traversing yarn guide of a yarn traversing device 21. Downstream of the yarn traversing device 21, a contact roll 22 is arranged. The contact roll 22 lies against the circumference of a package 23 that is to be wound. The package 23 is wound on a rotating winding spindle 24. To this end, a spindle motor 25 drives the winding spindle 24. The drive of the winding spindle 25 is controlled as a function of the rotational speed of the contact roll such that the circumferential speed of the package and, thus, the winding speed remain substantially constant during the winding operation. Between the lubrication device 16 and the takeup device 20, a treatment device 17 is arranged for treating the yarn 12. In the embodiment shown in Figure 1, an entanglement nozzle 18 forms the treatment device 17. As a function of the production process, it is possible to arrange in the treatment device one or more heated or unheated godets, so that the yarn is drawn before being wound. There is likewise a possibility of arranging additional heating devices for drawing or relaxing within the treatment zone 17. In the spinning apparatus shown in Figure 1, a polymer melt is delivered to the spin head 1 and extruded through spinneret 2 to a plurality of filaments 5. The filament bundle is withdrawn by takeup device 20. In this process, the filament bundle advances at an increasing speed through spin shaft 6 wij:hin inlet cylinder 4. Subsequently, the filament bundle enters cooling tube 8 through funnel-shaped inlet 9. In the cooling tube 8, suction device 15 generates a vacuum. Ambient air outside of inlet cylinder 4 is thereby sucked into spin shaft 6. The air entering spin shaft 6 is proportional to the gas permeability of the wall of inlet cylinder 4. The inflowing air leads to a precooling of the filaments, so that its surface layers firm up. In their core, however, the filaments remain molten. The quantity of air is then sucked together with the filament bundle through inlet 9 into cooling tube 8. The air stream is accelerated due to the narrowest cross section formed at the end of inlet 9 and the action of suction device 15 such that an air stream counteracting the movement of the filaments is no longer present in the cooling tube. The narrowest cross section extends over "the entire region of cylindrical tube portion 32. Thus, the length of cylindrical tube portion 32 defines the acceleration distance within cooling tube 8. In this connection, the cylindrical tube portion may have a length from few millimeters to 500 mm or greater. The air stream in direction of the advancing yarn decreases the stress on the filaments. The solidification point moves away from the spinneret. It is thus possible to influence the relationship between spinning"speed and drawing during the production of the yarn such that high elongation values are obtained despite high spinning speeds. Within the cooling tube 8, the filaments undergo a cooling. For a further cooling, the air supply device generates an additional cooling air stream. To this end, the filaments advance through second cooling tube 35 downstream of first cooling tube 8. The outlet cone 10 of the first cooling tube and the funnel-shaped inlet 36 of the second cooling tube 35 terminate both in outlet chamber 11. The air stream from cooling tube 8 and the cooling air stream from cooling tube 35 are sucked under the action of suction device 15 into the outlet chamber 11. They exit therefrom via screen cylinder 30 through suction stub 14. Thereafter, the entire air stream is removed by suction device 15. On the outlet side of cooling tube 35, the filaments 5 emerge from outlet opening 13, and enter lubrication device 16. The lubrication device 16 combines the filaments to a yarn 12. To increase cohesion, the yarn 12 is entangled in an entanglement nozzle 18 before being wound. In the takeup device, the yarn 12 is wound to a package 23. It is possible to use the arrangement shown in Figure 1 to produce, for example, a polyester yarn that is wound at a takeup speed greater than 7,000 m/min. The spinning apparatus of Figure 1 is characterized in that the air quantity entering the inlet cylinder is adapted to the delayed heat treatment of the filaments. In this connection, it is possible to influence with" advantage both precooling and delayed solidification of the filaments. The final cooling of the filaments occurs in a second zone that is formed by the second cooling tube 35. To intensify the cooling, it would be possible to supplement air supply device 35 with an air stream generator that could connect to the outlet end of the second cooling tube 35. Figure 2 shows a further embodiment of a spinning apparatus according to the invention, wherein an air supply device 34 with an air stream generator 38 is provided. The spinning apparatus shown in Figure 2 differs from the embodiment shown in Figure 1 by the configuration of the air supply device 34. Therefore, as regards the description of the remaining structural elements that are indicated by identical numerals, the description of the embodiment of Figure 1 is herewith incorporated by reference. In the embodiment of the spinning apparatus as shown in Figure 2, the air supply device 34 is arranged in the region of the cylindrical portion 32 of cooling tube 8, To this end, the cooling tube 8 comprises an opening 39 in the wall of cylindrical tube portion 32. The opening 39 is formed by an annular, perforated sheet element 40 that is inserted into the wall of cylindrical tube portion 32. The opening 39 in the wall of cylindrical tube portion 32 is enclosed by an air chamber 42 externally surrounding the wall of cylindrical tube portion 32. The air chamber 42 comprises a supply line 41. The supply line 41 connects to an air stream generator 38. Between air stream generator 38 and air chamber 42, the supply line 41 accommodates an adjustable throttle 44, which is adapted for controlling the free flow cross section of supply line 41. In the embodiment of the spinning apparatus according to the invention as shown in Figure 2, the additional air stream is generated by the interaction of suction device 15 and air stream generator 38 of air supply device 34. In this arrangement, the cooling air stream enters the acceleration length of cooling tube 8 through opening 39. To avoid turbulences inside the cooling tube 8, the cooling air stream enters opening 39 through a plurality of perforations of perforated sheet element 40. The cooling air stream and the air stream mix and flow in direction of the advancing yarn to the outlet 33 of cooling tube 8. There, the cooling air stream and air stream enter outlet chamber 11, and are removed by suction device 15 via suction stub 14. The filament bundle is cooled inside cooling tube 8. On the underside of outlet chamber 11, the filament bundle leaves the cooling zone through an outlet opening 13. Subsequently, lubrication device 16 combines the filament bundle to the yarn. The embodiment shown in Figure 2 is characterized in that an intense cooling can occur within the cooling tube despite a delayed cooling and, thus, the relocation of the solidification point. The air stream entering at inlet 9 of cooling tube 8 and the position of the air supply device 34 on the cooling tube are adapted such that the cooling air stream enters the cooling tube 8 shortly before or shortly after the solidification point of the filaments. Thus, a high uniformity is accomplished in the formation of the filaments or yarn. An opening that is locally defined on the circumference may also form the air supply device 34. Likewise, it is possible to construct the air supply device 34 without air stream generator 38, so that ambient air is able to enter directly the air chamber 42, via supply line 41, due to the action of suction device 15. Figure 3 shows a modification of the air supply device 34, as could be used, for example, in the spinning apparatus of Figure 2. In this embodiment, an axially slidable sleeve 43 covers the opening 39 in the cylindrical tube portion 32 of cooling tube 8. The portion of opening 39 that is not covered by sleeve 43 connects to the ambient air. Thus, due to the vacuum atmosphere in cooling tube 8, an additional cooling air stream will form that flows via the free flow cross section of opening 39 into the interior of cooling tube ,8. In direction of the advancing yarn upstream of air supply device 34, the filaments 5 are contacted by the air stream sucked in at the inlet end of air supply device 34, which delays cooling of the filaments. Only after the filaments 5 have passed air supply device 34, will cooling of the filaments be intensified by the additionally inflowing cooling air stream, so that the filaments are cooled when they leave cooling tube 8. By adjusting the sleeve 43, it is possible to regulate the air quantity for forming the cooling air stream as a function of the yarn denier or polymer type. Figure 4 shows a further embodiment of an air supply device 34. The spinning apparatus is identical with the embodiment of Figure 2. To this extent, the description of Figure 2 is herewith incorporated by reference. In the embodiment of the spinning apparatus of Figure 4, the air supply device 34 is formed at the outlet end of cooling tube 8. To this end, the outlet cone 10 comprises a gas-permeable wall. The opening 39 in the wall of cooling tube 8 thus extends from the end of cylindrical tube portion 32 to the outlet 33. The gas-permeable wall of outlet cone 10 is arranged inside an air chamber 42 that surrounds cooling tube 8, The air chamber 42 comprises a supply line 41 that connects at its end to the ambient air. An adjustable throttle 44 controls the free flow cross section of supply line 41. In the spinning apparatus shown in Figure 4, suction device 15 generates the additional cooling air stream. In this process, the ambient air enters air chamber 42 through supply line 41. From the air chamber 42, the ambient air enters the cooling tube due to the vacuum atmosphere therein through the air-permeable wall of outlet cone 10. Based on the widening cross section in direction of the advancing yarn, an intense mixing occurs between the air stream accompanying the filaments and the laterally entering cooling air stream. This results in an intense cooling of the filaments. The cooling air stream and air stream are removed by suction device 15 through outlet chamber 11 and suction stub 14. Figure 5 shows a further embodiment of a cooling system of a spinning apparatus. In this embodiment, the air supply device is arranged downstream of inlet 9 in the region of the cylindrical portion 32 of cooling tube 8. To this extent, the embodiment shown in Figure 5 is identical with the embodiment shown in Figure 2, whose description is herewith incorporated by reference. The air supply device 34 of Figure 5 comprises in the wall of cooling tube 8 an opening 39 that is constructed in the form of a bore. Furthermore, the air supply device comprises an injector 45 and a source of compressed air 47. The source of compressed air 47 connects to a nozzle bore 46 of injector 45. The injector 45 and the source of compressed air 47 act as an air stream generator and advance a cooling air stream through the opening 39 into the interior of cooling tube 8. The nozzle bore 46 of injector 45 is made such that between the center axis of the cooling tube and the nozzle bore an angle Besides the cooling effect, the embodiment of the air supply device of Figure 5 has proven itself in particular for threading the filaments at the beginning of the process. The injector introduces the cooling air stream at a high acceleration into the interior of the cooling tube. Due to the suction effect of suction device 15, this cooling air stream propagates substantially in the center region of the tube cross section. This flow entrains the filaments and guides the filament bundle reliably through cooling tube 8. To further increase the effect, it would be possible to arrange on the opposite side of the wall a second or further air supply device with injector. The air supply devices shown in Figures 2-4 comprise each annular openings that extend over the entire circumference of the cooling tube. However, it is also possible to limit the openings to extend only partially over a certain circumferential section of the cooling tube. It is also possible to form several openings side by side and/or one after the other in the wall of the cooling tube. The configuration of the openings or insertion of porous walls, such as for example the perforated sheet element, permit the flow of the cooling air stream to enter the interior of the cooling tube substantially without causing major turbulences. The embodiment of the air supply device shown in Figure 4 generates a flow with especially little turbulence for cooling the filaments, which increases spinning reliability or the stabilized advance of the yarn. The invention is not limited to a certain configuration of the cooling tube. The cylindrical shapes illustrated in the embodiments are exemplary and may easily be replaced with an oval shape, or even with an angular shape of the cooling tube when rectangular spinnerets are used. It can as well be advantageous - especially for the production of highly oriented yarns - to make the cylindrical portion of the cooling tube very short. In an extreme case the cooling tube could consist of an inlet cone and an outlet cone only , such that the air supply device according to the embodiment as shown in fig. 2 would be located in the region of the outlet cone 10. NOMENCLATURE 1 Spin head 2 Spinneret 3 Melt line 4 Inlet cylinder 5 Filaments 6 Spin shaft 7 Wall 8 Cooling tube 9 Inlet cone 10 Outlet cone 11 Outlet chamber 12 Yarn 13 Outlet opening 14 Suction stub 15 Air stream generator, suction device 16 Lubrication device 17 Treatment device 18 Entanglement nozzle 19 Apex yarn guide 20 Takeup device 21 Yarn traversing device 22 Contact roll 23 Package 24 Winding spindle 25 Spindle drive 26 Perforation 27 Flow profile 29 Perforation 30 Screen cylinder 31 Heating device 32 Tube portion 33 Outlet 34 Air supply device 35 Cooling tube 36 Inlet ■37 Outlet 38 Air stream generator 39 Opening 40 Perforated sheet element 41 Supply line 42 Air chamber 43 Sleeve 44 Throttle 45 Injector 46 Nozzle bore 47 Source of compressed air WE CLAIM: 1. An apparatus for spinning a synthetic yam (12), which is formed by combining a filament bundle consisting of a plurality of individual filaments and which is wound to a package (23) by a takeup device (20) downstream of the spinning apparatus, the apparatus comprising a spinneret (2); a cooling tube (8) extending at a distance from spirmeret (2) downstream thereof, the cooling tube comprising an inlet (9) with a narrowest cross section in cooling tube (8), a cylindrical portion (32) cormected to the inlet (9), and an outlet (33); a gas-permeable inlet cylinder (4) arranged between spinneret (2) and inlet (9) of cooling tube (8); a suction device (15) that cormects to the outlet (33) of cooling tube (8) such that it generates an air stream in cooling tube (8) in direction of the advancing yam; and an air supply device (34) for generating an additional cooling air stream in axial direction of the cooling tube (8) for cooling filaments (5), characterized in that the air supply device (34) is formed in direction of the advancing yam downstream of the inlet (9) in the region of the cooling tube (8) or downstream of the outlet (33) of the cooling tube (8). 2. The spirming apparatus as claimed in claim 1, wherein the air supply device (34) connects to the cooling tube (8) such that the cooling air stream and the air stream flow jointly in direction of the advancing yam. 3. The spinning apparatus as claimed in claim 2, wherein the air supply device (34) is formed by at least one opening (39) in the wall of cooling tube (8) between the inlet (9) and the outlet (33) of the cooling tube, the cooling stream entering the cooling tube (8) through the opening is generated from the ambient air by means of the suction device (15). 4. The spinning apparatus as claimed in claim 2, wherein the air supply device (34) is formed by at least one opening (39) in the wall of cooling tube (8) between the inlet (9) and the outlet (33) of cooling tube (8) and by an air stream generator (38) connecting to the opening (39), the cooling stream entering the cooling tube (8) through the opening (39) is generated by means of the air stream generator (38). 5. The spinning apparatus as claimed in claim 4, wherein the air stream generator is an injector (45) with at least one nozzle bore (46) and a source of compressed air (47) connected to the injector (45), that the nozzle bore (46) of the injector (45) terminates directly in the opening (39), between the center axis of the cooling tube (8) and the nozzle (46) an angle smaller than 90°, preferably 15° to 30° is formed in direction of the advancing yam. 6. The spinning apparatus as claimed in claim 3 or 4, wherein the air supply device (34) comprises an adjustment means (43) for varying the free flow cross section of the opening (39). 7. The spinning apparatus as claimed in claim 6, wherein the adjustment means is a sleeve (43) arranged on cooling tube (8), which is slidable for fully or partially closing the opening (39). 8. The spinning apparatus as claimed in claim 6, wherein the adjustment means consists of an air chamber (42) externally enclosing the opening (39) in cooling tube (8), and a throttling device (44), which controls in supply line (41) the air supply to air chamber (42). 9. The spinning apparatus as claimed in claim 8, wherein the supply line (41) of air chamber (42) connects with its free end to the air stream generator (38). 10. The spinning apparatus as claimed in any one of claims 3-9, wherein the opening (39) is formed in the wall of cooling tube (8) by an annular, perforated sheet element (40), which extends over the entire circumference of the cooling tube. 11. The spinning apparatus as claimed in claim 10, wherein the perforated sheet element (40) is conically shaped with its cross section increasing in direction of the advancing yam and arranged in the extension of the cylindrical tube portion (32) at the outlet side of cooling tube (8). 12. The spinning apparatus as claimed in claim 1, wherein the air supply device (34) is arranged on the outlet side of cooling tube (8) such that the cooling air stream flows oppositely to the direction of the advancing yam. 13. The apparatus as claimed in claim 12, wherein the air supply device (34) is a second cooling tube (35) through which the filament bundle advances, and that the second cooling tube (35) connects in the axial extension of the first cooling tube (8) to the outlet (33) of the first cooling (8) such that the cooling air stream in the second cooling tube (35) is generated by the suction device (15). 14. The spinning apparatus as claimed in claim 13, wherein the second cooling tube (35) comprises a funnel-shaped inlet (36) and a cylindrical outlet (37) with an air-permeable wall. 15. The spinning apparatus as claimed in claim 13 or 14, wherein the outlet (33) of the first cooling tube (8) and the inlet (36) of the second cooling tube (35) are interconnected by an outlet chamber (11), with the suction device being connected to the outlet chamber. 16. A method of spinning a synthetic yam (12) formed by combining a filament bundle consisting of a multiplicity of individual filaments (5) comprising the steps of extruding the filaments from a polymer melt by means of a spinneret (2); cooling the filaments by means of air in a pre-cooling zone and a cooling zone; generating an air- stream in the direction of the advancing yam for assisting the advance of the filaments; the cooling and the spinning feed are adapted to each other such that the filaments firm up only within the coding tube and are combined to the yam at the end of the cooling zone, the filaments are cooled for firming up before being combined to the yam by an additional axial cooling air stream generated in the cooling zone below an inlet (9) or below an outlet (33); and winding the yam to a package by a take up device (20) downstream of the spinning apparatus. 17. The method as claimed in claim 16, wherein the cooling air stream flows within the cooling zone in the same direction as the air stream. 18. The method as claimed in claim 16, wherein the cooling air stream flows within the fooling zone oppositely to the direction of the advancing yam.

Documents:

in-pct-2001-0101-che abstract duplicate.pdf

in-pct-2001-0101-che abstract.pdf

in-pct-2001-0101-che claims duplicate.pdf

in-pct-2001-0101-che claims.pdf

in-pct-2001-0101-che correspondence-others.pdf

in-pct-2001-0101-che correspondence-po.pdf

in-pct-2001-0101-che description (complete) duplicate.pdf

in-pct-2001-0101-che description (complete).pdf

in-pct-2001-0101-che drawings.pdf

in-pct-2001-0101-che form-1.pdf

in-pct-2001-0101-che form-19.pdf

in-pct-2001-0101-che form-26.pdf

in-pct-2001-0101-che form-3.pdf

in-pct-2001-0101-che form-5.pdf

in-pct-2001-0101-che pct.pdf

in-pct-2001-0101-che petition.pdf