Title of Invention

"METHOD AND APPARATUS FOR PRODUCING STAPLE FIBERS"

Abstract

The invention relates to a method and an apparatus for producing staple fibers, wherein in a first step a tow is formed from melt spun filament strands and deposited into a can, and wherein in a second process step the tows of a plurality of cans in a can creel are withdrawn, treated, and cut to staple fibers. To obtain as much as possible short times of interruption between the first and the second process step, the invention provides for depositing the tow in the first process step directly into the can accommodated in the can creel, with the cans of the can creel being filled one after the other. CLT01/4682987vl

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10) TITLE "METHOD AND APPARATUS FOR PRODUCING STAPLE FIBERS" APPLICANT Saurer GmbH & Co. KG Landgrafenstrasse 45 D-41069 Monchengladbach Germany Nationality : a German company The following specification particularly describes the nature of this invention and the manner in which it is to be performed METHOD AND APPARATUS FOR PRODUCING STAPLE FIBERS The invention relates to a method of producing staple fibers as defined in the preamble of claim 1 as well as an apparatus for carrying out the method as defined in the preamble of claim 8. Basically, two different kinds of methods and apparatus are known for producing staple fibers. In a first kind of method and apparatus, the staple fibers are produced in a two-step process. To this end, a plurality of filament strands are spun from a polymer melt in a first step, and combined to a tow after cooling. At the end of the first process step, the tow is deposited in a can. In a second process step, a plurality of tows are withdrawn by a treatment unit from a plurality of cans that are accommodated in a can creel. The tows are joined to one combined tow, treated, and finally cut to staple fibers. Such two-step processes are used in particular for processing very coarse total deniers, such as, for example, greater than 200,000 deniers. The invention is based on such methods and apparatus. In the two-step process, it is important that the tows be temporarily stored between the first process step and the second process step, since it is common practice to join in the treatment unit a plurality of tows produced in a first spinning process to a combined tow, and to further process the latter. CLT01/4682987vl For the temporary storage of the spun tows, cans are provided that are reciprocated by costly transportation devices between the spin unit and a can creel associated to the treatment unit. To ensure that the can creel has a supply of cans for carrying out the second process step, a can magazine is provided that temporarily stores previously filled cans. The known methods and apparatus for producing staple fibers in two process steps thus require a great deal of coordination as well as costly transportation devices and a large-surface installation space. In comparison therewith, methods and apparatus are known, wherein the staple fibers are produced in a one-step process. In this process, the spinning, drawing, crimping, and cutting steps of a tow follow one another directly. However, such methods basically have the disadvantage of small production outputs, since both the withdrawal of the tow from the spin unit and the drawing of the tow must essentially be performed by the treatment unit. In particular in the case of coarser total deniers of the tows, irregularities in the physical properties of the fibers become very noticeable. It is therefore an object of the invention to provide a method and an apparatus for producing staple fibers in a two-step process, which permit storing and making available tows in the transition from the first process step to the second process step in a simple way with simple means. A further object of the invention is to further develop the known method and the known apparatus such that they permit further processing the freshly spun tow to the end product with as little time of interruption as possible. CLT01/46S298'Jvl In accordance with the invention, the object is accomplished by a method with the steps of claim 1, as well as by an apparatus with the features of claim 8. Advantageous variants of the method according to the invention are defined in the dependent claims 2-7. Advantageous further developments of the apparatus are defined in the dependent claims 9-17. The invention distinguishes itself essentially in that it does not require costly auxiliary devices for transporting the cans to the spin units. In the first process step, the invention provides for depositing the tow directly into a can that is accommodated in a can creel. The interaction of the spin unit and the can creel permits designing in an advantageous manner a compact combined production line, in which the can creel represents a common interface between the spin unit and the treatment unit. To enable as much as possible a continuous process sequence, the further developments of the invention are especially advantageous, which provide next to a first can creel a second can creel with a plurality of cans. Thus, for example an advantageous variant of the method makes it possible to deposit the tow in the first process step into the cans of the first creel, while at the same time, in the second process step, the tows are withdrawn from the cans of the second creel. In this connection, it is possible to achieve an almost continuous operation in such a manner that the cans of the first can creel and the cans of the second can creel are alternately filled with the tow, and that the tows are alternately removed from the cans of the second creel and from the cans of the first CLT01/4682987vl creel. In particular in the second process step, this results in very short interruption times, since an exchange of the cans in the can creel is omitted. To continue the process, it is necessary to change only the can creels, which can be realized in very short times. For purposes of filling the cans accommodated in a can creel in any position, the spin unit includes in accordance with an advantageous further development of the invention, a movable depositing device that is supported and guided by guide means above the creel. With that, it is possible to deposit the tow in any desired position of the can creel into a can accommodated therein. The tow may be deposited both by an oscillating movement that is imparted to the depositing device, or by an oscillating movement that is imparted to the can accommodated in the can creel. This ensures a high degree of filling with a corresponding filling density. However, it is preferred to generate the oscillating movement of the tow by the depositing device or by a conveying means that is mounted for movement to the depositing device. An especially advantageous further development of the apparatus according to the invention provides for associating the depositing device to a feed system, which advances the tow after withdrawing it from the spinnerets. This further development is especially advantageous for being able to fill can creels with a large number of cans and the therewith connected great travel distances with the tow under an adequate tension. in this connection, the feed system CLT01/46829S7vl 5 associated to the depositing device is used for building up a tensile force. To make the apparatus as compact as possible for carrying out the two-step process, a preferred further development of the invention provides for arranging the spinnerets and the withdrawal systems of the spin unit above the can creel. This arrangement permits mounting the spinnerets in a centered or offset relationship with the can creel, with the arrangement in tiers it becomes possible to keep the deflections small that are needed for depositing the tow. The further development of the invention, which provides for associating in the can creel to each can a withdrawal element that is adapted for moving between an idle position and an operating position, is especially advantageous for permitting on the one hand an uninterrupted removal of the tows from the cans, and on the other hand for making available a full opening cross section of the cans for filling. In the following, the method of the invention is described in greater detail by means of an embodiment of the apparatus according to the invention with reference to the attached drawings, in which: Figure 1 is a schematic top view of a layout of the apparatus according to the invention,- and Figures 2-4 are a plurality of schematic views of a first embodiment according to the invention. Figure 1 illustrates a top view of a layout of the apparatus according to the invention. The apparatus comprises a spin unit 1, two can creels 2.1 and 2.2 cooperating with the spin unit 1, as well as a treatment unit 3. The spin unit 1 includes a plurality of spinning positions for melt spinning a plurality of filament strands, which are joined to a tow 11 by means CLTOl/4682987vl 6 of a withdrawal system 9. Via the withdrawal system 9, the tow advances to a depositing device 10 that is arranged for being positioned above the can creels 2.1 and 2.2. The can creels 2.1 and 2.2 accommodate a plurality of cans 13. In the arrangement illustrated in Figure 1, the depositing device 10 is associated to the can creel 2.1, and in the process of filling a first can 13 of the creel. The depositing device 10 can be moved to each can of the can creel 2.1 for successively filling the cans 13 of the creel 2.1 with the tow. The cans 13 accommodated in can creel 2.2 are already filled. The tows of the cans 13 of can creel 2.2 are jointly withdrawn by the treatment unit 3 and combined to one tow 14. To this end, a plurality of guide rolls 22 are associated to the can creels 2.1 and 2.2 on their respective delivery sides. The treatment unit 3 comprises withdrawal systems and draw systems as well as additional treatment devices for cutting at its end the tow 14 to the desired staple fibers. In the schematic arrangement shown in Figure 1, the cans 13 of the can creel 2.1 are being filled with a tow, whereas the cans 13 of the can creel 2.2 are being emptied, in that the treatment unit 3 withdraws the tows. After all cans 13 in the can creel 2.1 have been filled, and after all cans 13 in the can creel 2.2 have been emptied, the association will be changed. The tow 14 that is withdrawn and treated by the treatment unit 3 is then formed by the tows that are withdrawn from the cans 13 of the can creel 2.1. At the same time, the cans 13 of the can creel 2.2 are filled with the tows. The special advantage of the method according to the invention and the apparatus of the invention CLT01/4682987vl 7 lies in particular in a substantially continuous operation of the two process steps with only short times of interruption. In particular the avoidance of costly transportation steps brings considerable savings in time. Furthermore, the can creels 2.1 and 2.2 can be arranged relative to each other, without having to take into account any transportation paths or transportation steps. It is thus possible to provide very compact arrangements of can creels, which directly cooperate with the adjacent or superposed spin unit 1 or with the adjacent or superposed treatment unit 3. Figures 2-4 schematically illustrate different views of a first embodiment of the apparatus according to the invention for carrying out the method of the invention. In this connection. Figure 2 is a side view of the complete production line. Figure 3 a front view of the can creels, and Figure 4 a top view of the can creels. Unless express reference is made to one of the Figures, the following description will apply to all Figures. To begin with, the general construction of the embodiment of the apparatus according to the invention is described in greater detail with reference to Figure 2. For carrying out a first process step of the method according to the invention, the embodiment comprises a spin unit 1, and for carrying out a second process step, it comprises a treatment unit 3. The spin unit 1 and the treatment unit 3 cooperate with two juxtaposed can creels 2.1 and 2.2. For melt spinning a tow 11, the spin unit 1 comprises a plurality of spinnerets 6.1-6.3. In the present embodiment, the number of spinnerets is exemplary. Spin units of this type may comprise a CLT01/46829E7vl 8 plurality of spinnerets. Associated to each spinneret 6.1, 6.2, and 6.3 is a spin pump 5.1, 5.2, and 5.3. The spin pumps 5.1-5.3 connect via a melt distributor 32 to an extruder 4. The spinnerets 6.1-6.3 are made annular for purposes of extruding a plurality of filaments in a circular arrangement to a filament strand. Downstream of the spinnerets 6.1-6.3, outflow quench devices 7.1-7.3 extend each in concentric relationship with a spinneret. Each of the outflow quench devices 7.1-7.3 connects to a cooling air supply line (not shown) to generate a cooling air stream for cooling the filament strands. Downstream of each of the outflow quench devices 7.1-7.3, lubrication devices 8.1-8.3 are provided, each for bundling the filaments. In the direction of the advancing filament strands, a withdrawal system 9 follows downstream of the lubrication devices 8.1-8.3. The withdrawal system 9 comprises a plurality of rolls arranged in side-by-side relationship. The rolls are driven, in the inlet region of the withdrawal system 9, it is preferred to provide lubrication rolls which combine the filament strands 12.1-12.3 to a tow 11. Arranged downstream of the withdrawal system 9 are rolls, which advance the tow 11 to a depositing device 10. A guide means 15 supports the depositing device 10 and permits positioning it above the can creels 2.1 and 2.2. To this end, the spin unit 1 and the can creels 2.1 and 2.2 are arranged in tiers, one on top of the other. The depositing device 10 comprises a conveying means 20 which delivers the tow 11 into a can of the can creel 2.1. The conveying CLT01/4682987vl 9 means 20 is coupled with a moving means 19, which causes the conveying means 20 to perform an oscillating pivotal movement- With that, it is possible to deposit the tow 11 evenly over the entire opening cross section of the associated can 13, A depositing device of this type is disclosed, for example, in EP 1 369 370 A2. To this extent, the cited publication is herewith explicitly incorporated by reference, so that a further description may be omitted. The guide means 15 as well as the arrangement of the can creels 2.1 and 2.2 are described in greater detail in the following. The tows stored in the cans 13 of the second can creel 2.2 are withdrawn by the treatment unit 3. The treatment unit 3 is generally named a so-called fiber line, and comprises a plurality of treatment devices for being able to draw and treat the individual tows that have been joined to one tow 14. The setup of the treatment device 3 shown in Figure 2 is exemplary with respect to the arrangement and number of the treatment devices, and shows only the essential treatment devices that are required for carrying out the second process step. A draw system 25 removes the tows 11 from the cans 13 of can creel 2.2. In this process, the tows 11 are combined to one tow 14 and advanced over guide rolls 22 and deflection rolls 31. Downstream of the draw system 25 is a crimping device 27. Normally, the crimping device 27 is constructed as a stuffer box crimping mechanism, in which the tow is jammed by a feed means into a stuffer box. As conveying means one could use rolls, for example, in the case of a two-dimensional crimp. The crimping device 27 is followed by a drying device 28, a tension adjusting device 29, CLT0l/46829S7vl 10 and finally a cutting device 30. The use of a drying device depends on the type of the polymer. To produce the staple fibers, a tow 11 is melt spun, in accordance with the arrangement of the embodiment shown in Figure 2 by means of the spin unit 1 in a first process step. To this end, a thermoplastic plastic is melted by the extruder 4 and supplied to the spin pumps 5.1-5.3. The spin pumps 5.1-5.3 advance the plastic melt under a pressure to the associated spinnerets 6.1-6.3. Each of the spinnerets 6.1-6.3 comprises a plurality of spin holes, so that one filament strand is extruded from each spin hole. Spinnerets of this type may have as many as several thousand spin holes. From the spinnerets 6.1-6.3, the filament strands are jointly removed by the withdrawal device 9. In this process, the filament strands are cooled, lubricated, and combined to filament bundles 12.1-12.3. Before entering the withdrawal device 9, the filament bundles 12.1-12.3 are combined to a tow 11. From the withdrawal device 9, the tow 11 advances over a guide roll 21 to the depositing device 10. The depositing device 10 is mounted to the guide means 15, and can be selectively moved to each can 13 within the can creel 2.1, The depositing device is used to advance the tow 11 into a can 13 of the can creel 2-1. At the same time, the treatment device 3 withdraws the tows of the adjacent can creel 2.2 to perform the second step of the method, according to the invention. In this step, the tows 11 that are deposited in the cans 13 of can creel 2.2 are jointly withdrawn by the draw system 25 via the guide rolls 22 and deflection rolls 31, and joined to one tow 14 before entering the draw system 25. The tow 14 CLT01/4682987vl 11 advances through the fiber line, and in so doing, it is drawn in the draw system 25. To this end, it is preferred to provide a plurality of heated and also unheated draw rolls 26. After the drawing step, the tow advances through a setting device (not shown). In this process, one may precede or insert one or more thermal treatments. After the setting step, the tow 14 enters the crimping device 27. Subsequently, the crimped tow 24 advances via the tension adjusting device 29 into the cutting device 30, which cuts the tow 14 to staple fibers of a predetermined length. Thereafter, the produced staple fibers can advance, for example, pneumatically to a baling press for being compacted to a bale. This completes the second process step of the method according to the invention. To explain the cooperation between the first process step and the second process, the devices for filling and emptying the can creels 2.1 and 2.2 are described in greater detail in the following with reference to Figures 3 and 4. The following description will apply to both Figures, unless express reference is made to one of the Figures. The can creels 2.1 and 2.2 are arranged side by side with a small spacing in between. In this arrangement, the cans 13 are accommodated in the can creel 2.1, and the cans 13 in the can creel 2.2 in two parallel lines side by side. On the upper side of the can creels 2.1 and 2.2, each can is provided with a withdrawal element 23 which is mounted to a free end of a pivot arm 24. The withdrawal element 23 could be formed, for example, by an eyelet or a roll. The pivot arm 24 is mounted for pivotal movement to the can creels 2.1 and 2.2. The pivot arm 24 permits moving the withdrawal element 23 selectively to an idle CLT01/4682987vl 12 position on the side next to the can 13 or to an operating position in the center of the can 13. During the filling of a can 13, the pivot arm 24 with the withdrawal element 23 is moved to an idle position as shown in the case of can creel 2.1. To withdraw the tows from the cans 13 of the can creel 2.2, all withdrawing elements 23 are pivoted with their pivot arms 24 to the operating position as shown in the case of can creel 2.2 For withdrawing the tows 11 from the cans 13 of can creel 2.2, the respective tows are slidingly guided over the withdrawing element 23 and removed by the treatment unit 3. For filling the cans 13 of can creel 2.1, the depositing device 10 is supported by the guide means 15. In the present embodiment, the guide means is formed by a guide frame 1$ that extends over the can creels 2.1 and 2.2. The guide frame 16 mounts a carriage 17 which is adapted for reciprocal movement within the guide frame 16 by a drive not shown. The carriage 17 is provided with a linear guideway 18 for moving therein a holder 33 of the depositing device 10. The holder 33 can be activated in the linear guideway 18 by a drive (not shown) and be moved transversely to the longitudinal movement of the carriage 17. Thus, by coordinating the movement of the carriage 17 and the movement of the holder 33 in the linear guideway 18, it becomes possible to move the depositing device 10 to each can 13 of the can creel 2.1 or 2.2. The holder 33 mounts a conveying means 20 in the form of two reels. These reels are adapted for performing an oscillating pivotal movement transversely to the direction of movement of the holder 33 by means of the moving means 19 that may be formed by a pivotal CLT01/46S2987vl 13 support. A conveying means of this type with a pivotal support is disclosed in EP 1 369 370 A2, so that for a description in greater detail the cited publication is herewith incorporated by reference. For depositing a tow, the conveying means 20 and the holder 33 are caused to perform an oscillating movement within a filling cross section above the can 13. This makes it possible to attain a uniform deposit of the tow 11 in every region of the can. Upstream of the conveying means 20 is a feed system 21 that advances the tow 11 to the conveying means 20. Preferably, the feed system 21 comprises a plurality of driven rolls. With that, it is possible to attain an adequate tension in the tow regardless of the travel of the depositing device 10. The depositing device 10 shown in Figures 2-4 is only exemplary, and shows a possibility of depositing a tow into a can 13. In principle, the depositing device could be formed by stationary conveying means 20, to which one would associate an additional guide means that is adapted for oscillating movement to deposit the tow into the can. However, it is also possible to combine a depositing device 10 with a can traverse mechanism. In this case, the conveying means 20 could also be made immobile. For filling, the can would then perform an oscillating movement in the can creel. However, it is basically possible to use all devices that are suited to perform a movement of the conveying means for guiding the tow while advancing it, in such a manner that a can is evenly filled with a great filling density. In their construction and arrangement, the embodiments shown in Figures 1-4 are exemplary. In CLT0I/4682987vl particular, the embodiment of Figure 4 may be constructed with additional treatment means as well as similar constructional variants. The invention encompasses all apparatus and methods for producing staple fibers, wherein tows formed from a plurality of filament strands are deposited into a can of a can creel for temporary storage between a first process step and a second process step. NOMENCLATURE I Spin unit2.1, 2.2 Can creel 3 Treatment unit 4 Extruder 5.1-5.3 Spin pump 6.1-6.3 Spinneret 7.1-7.3 Outflow quench device 8.1-8.3 Filament lubrication device 9 Withdrawal system 10 Depositing device II Tow 12.1-12.3 Filament bundle 13 Can 14 Combined tow 15 Guide means 16 Guide frame 17 Frame carriage 18 Linear guideway 19 Moving means 20 Conveying means 21 Feed system 22 Guide roll 23 Withdrawing element 24 Pivot arm 25 Draw system 26 Draw rolls 27 Crimping device 28 Drying device 29 Tension adjusting device 3 0 Cutting device 31 Deflection rolls 32 Melt distributor 33 Holder CLT01/4682987vl CLAIMS 1. Method of producing staple fibers, wherein a tow of melt spun filament strands is formed and deposited into a can in a first process step, and wherein the tows of a plurality of cans in a can creel are withdrawn, treated, and cut in a second process step, characterized in that in the first process step, the tow is directly deposited into the can accommodated in the can creel, with the cans of the can creel being filled one after the other. 2. Method of claim 1, characterized in that in the first process step, the tow is deposited into the cans of a first can creel, and that the tows in the cans of a second can creel are simultaneously removed in the second process step. 3. Method of claim 1 or 2, characterized in that the cans of the first can creel and the cans of the second can creel are alternately filled with the tow, and that the tows from the cans of the second can creel and the tow from the cans of the first can creel are alternately withdrawn. 4. Method of one of claims 1-3, characterized in that the tow is deposited by a movable depositing device into each can that is to be filled, with the depositing device being guided above the can creel. CLT01/4682987vl 5. Method of claim 4, characterized in Chat for being deposited into the can, the tow performs an oscillating movement that is imparted to it by the depositing device. 6. Method of claim 5, characterized in that the oscillating movement of the tow is generated by a movably mounted conveying means. 7. Method of claim 4, characterized in that for depositing the tow, the can performs an oscillating movement in the can creel. 8. Apparatus for carrying out the method of one of claims 1-7, with a spin unit (1) for melt spinning and depositing a tow (11) into a can (13) in a first process step, with a can creel (2.1) for accommodating a plurality of cans (13), and with a treatment unit (3) for withdrawing the tows (11) from the cans (13) of the can creel (2.1), as well as for treating and cutting the tows (11) to staple fibers in a second process step, characterized in that the spin unit (1) and the can creel (2.1) are arranged relative to each other such that the tow (11) can be directly deposited into the can (13) accommodated in the can creel (2.1), and that the cans (13) of the can creel (2.1) C3.n be filled one after the other. 9. Apparatus of claim 8, CLTO1/4682987 vl 18 characterized in that a second can creel (2.2) is arranged adjacent to the first can creel (2.1), and that both can creels (2.1, 2.2) are arranged relative to the spin unit (1) such that the cans (13) of the two can creels {2.1, 2.2) can be alternately filled with the tow (11). 10. Apparatus of claim 9, characterized in that the two can creels (2.1, 2.2) are arranged relative to the treatment device (3) such that the tows (11) of the cans (13) of the two can creels (2.1, 2.2) can be alternately withdrawn. 11. Apparatus of one of claims 8-10, characterized in that the spin unit (1) comprises a movable depositing device (10), which is supported and moved by guide means (15) above the can creel (2.1, 2.2). 12. Apparatus of claim 11, characterized in that a moving means (19) is provided, which causes the depositing device (10) to perform an oscillating movement while depositing the tow (11). 13. Apparatus of claim 12, characterized in that the moving means (19) is associated to a conveying means (20) which is adapted for advancing the tow (11) into the respectively associated can (13). 14. Apparatus of claim 11, characterized in that CLT01/46S2987vl 19 a plurality of traversing means are provided, which are associated to the cans in the can creel, and which support the cans for oscillating movement. 15. Apparatus of one of claims 11-14, characterized in that a feed system (21) which guides the tow (11) after its withdrawal from the spinnerets is associated to the depositing device (10). 16. Apparatus of one of claims 8-15, characterized in that the spinnerets (6.1-6.3) and the withdrawal systems (9) of the spin unit (1) are arranged upstream of the can creel (2.1, 2.2), with the spinnerets (6.1-6,3) being mounted in centered relationship with the can creel (2.1, 2.2) or in offset relationship with the can creel (2.1, 2.2) . 17. Apparatus of one of claims 8-16, characterized in that to each can (13) in the can creel (2.1, 2.2), a withdrawing element (23) is associated, which is adapted for movement between an idle position and an operating position. Dated this 13 day of September 2006 CLT01/4682987vl

Documents:

3315-chenp-2006 complete specification as granted.pdf

3315-CHENP-2006 CLAIMS GRANTED.pdf

3315-CHENP-2006 CORRESPONDENCE OTHERS.pdf

3315-CHENP-2006 CORRESPONDENCE PO.pdf

3315-CHENP-2006 FORM-2.pdf

3315-CHENP-2006 FORM-3.pdf

3315-CHENP-2006 PETITION.pdf

3315-chenp-2006-abstract.pdf

3315-chenp-2006-claims.pdf

3315-chenp-2006-correspondnece-others.pdf

3315-chenp-2006-description(complete).pdf

3315-chenp-2006-drawings.pdf

3315-chenp-2006-form 1.pdf

3315-chenp-2006-form 18.pdf

3315-chenp-2006-form 26.pdf

3315-chenp-2006-form 3.pdf

3315-chenp-2006-form 5.pdf

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