EP1173634B1 - Cooling system for filament bundles - Google Patents

Abstract

A cooling system for filament bundles, which are spun from polymer melt by at least two spinneret units (1) disposed one beside the other and are drawn off by a draw-off system (17), the filament bundles (3a, 3) being cooled in a three-part shaft (A, B, C) by an equidirectional air stream, and the cross-section of the individual shaft parts (A and B) tapering such that the flow rate of the air increases approximately to the same extent as the draw-off speed of the filament bundles (3a, 3).

Description

The present invention relates to a cooling system for filament bundles, which by at least two arranged side by side Spinneret units spun from polymer melt and with one Deduct speed of ≥ 1000 m / min from a fume cupboard system be, the filament bundles by a rectified Air flow to be cooled.

Polymer melt spinning, in which several simultaneously Filament bundles spun, pre-stretched, cooled, prepared and after any further work steps are wound up are known. In conventional spinning systems, the freshly spun, soft Polymer filaments shortly after they emerge from the spinneret assembly cooled by a cross-flow blowing. Increased until it solidifies the speed of the filaments depends on the spinning speed the nozzle up to the winding speed, d. H. on this track the filaments are stretched. At the same time, this is the route during which the filaments are most sensitive to external influences are. U.S. Patent 3,551,949 (= DE-A 1 956 860) describes one Blow chute with cross-flow blowing for a single filament bundle, whereby air turbulence is reduced by inclined side walls. According to US Patent 3,684,416 (= DE-A 1 962 946), the space requirement can be reduced of blow chutes with cross-flow blowing for several filament bundles thereby reduce that the partitions between the individual Filament bundles are deformable.

A completely different cooling concept is based on the cooling of the filaments through a rectified accompanying air flow within one Protection tube per filament bundle, the air flow through blower u. Like. And / or by the caused by the filament advancement Suction is generated (U.S. Patents 5,688,458; 5,360,589; 5,340,517). By funnel-shaped design of the bottom of the otherwise cylindrical Protection tube can according to EP patent 0 396 646, the air consumption reduce and improve the uniformity of the filaments. Loud US Patent 3,611,485 is said to be the freshly spun filament bundle in one always free and uncontrolled cooling airflow is cooled, which is only filled up by fresh air as much as by the controllable output losses arise. Again, there is only one fireplace per Spinneret provided. U.S. Patent 3,707,593 discloses a spinning process described, which is only suitable for nonwoven production: In The freshly spun filaments are turned into a pressure-tight spinning tube cooled by means of the compressed air used for extraction, in one cylindrical tube without partitions also several filament bundles can be cooled.

The method of EP patent 0 682 720 also wants the Ambient air at the same speed as the filaments carry along in order to later reach the solidification point of the thread and to be able to increase the take-off speed. This is with economy, d. H. higher production speed same quality or higher quality at the same speed founded. This is to be achieved by a in the lower area Extended cylindrical protective tube with suction device. Produce air speeds that are of the order of magnitude Filament take-off speed is, but not a Speed profile, which by the pre-stretching of the still not solidified filament bundle due to speed increase considered.

Individual thread protection tubes are more expensive than a common channel for several threads and their handling is particularly disadvantageous: everyone single thread must be through him when placed on the winder associated protective tube can be passed manually. This is with the Design according to EP patent 0 682 720 particularly difficult due to the narrow opening at the lower end, which allows the intake of false air should prevent. Because of the narrowness of the pipes, the preparation order is also applied to the thread only after exiting the tube. This is a disadvantage compared to the methods with cross-flow blowing, the thread closure immediately after the individual filaments have cooled Aim and only insert thread guide elements after oiling. It is particularly disadvantageous and cost-intensive that the air extraction installed, operated and regulated for each individual thread protection tube must become.

The object of the invention is to provide a cooling system for filament bundles create, which the protection of the not yet solidified filaments and their careful cooling serves and at the same time one if possible easy handling and high economic efficiency.

This object is achieved according to the invention by a cooling system according to the information in the claims.

The cooling system is suitable for all those that can be processed by melt spinning Polymers, especially for textile polyester filaments with high Winding speed can be spun.

The idea of the invention is based on the fact that in a cylindrical tube an air column in itself flows at (almost) constant speed, even if the air layers in a parabolic flow profile slow down from the inside out. This is for the frozen one Thread that runs even at constant speed, meaningless, but not for the still soft, stretching filaments, whose Speed increases until solidification has occurred. If you now look at a conical tube, it is also here parabolic flow profile (slower from the inside to the outside becoming). But this profile is much stronger at the narrow end pronounced than at the beginning, d. H. the speed of the Air flow is not constant, but increases. And this does not apply only for standard cylindrical tubes, but also for tubes with rectangular cross section.

The idea of the invention further assumes that instead of individual, conical tubes for each individual thread, also a tapered one rectangular channel for all threads together can fulfill the task a supporting accompanying air flow with the most adapted Speed to produce the threads. The rectangular cross section, especially in connection with partitions between the individual Filament bundles, allows a more uniform cooling of all Individual filaments of the filament bundle than, for example, an oval one Cross-section. It is basically the same where and how the rejuvenation takes place. Preferably, however, the first part of the shaft (A) remain constant in width so that the individual filament bundles can be deducted in parallel and under the same conditions. This can by additional fenders between each Spinneret positions are still supported. Here's to the bottom At the end of the first shaft (A) there is also enough space for the usual position of the preparation oiler, which can also be adjustable in height to use the advantages of the invention for different titers can. Immediately before the transition to the next shaft (B) a thread guide housed.

Depending on whether the individual filament bundles individually or in groups shaft B has to be wound up together slightly tapered in depth or strongly tapered Cross-section. For individually wound, arranged side by side The width of the chute B remains unchanged over the bundles of filaments total shaft height and opposite shaft A. The depth of shaft B should be dimensioned at the lower end so that on the one hand false air and Turbulence is prevented, but on the other hand touching the Shaft walls through the filaments are excluded. this will due to a slight inclination of the front and / or rear wall of the Shaft B reached according to a slight taper. at a bundle of filaments to be wound up is additionally carried out lateral tapering of the shaft B, so that the threads save space can be continued. Shortly before the end of this second Shaft (B), the air is extracted, taking the air can be traced back to the spinning position to already tempered (because it was driven in a circle) to be reinserted close to the thread. If necessary, additional air volumes are through the upper open gap sucked in between the spinneret units and the first shaft (A). At the The transition from the second shaft (B) to the end shaft (C) can be further Thread guide be attached.

The idea of the invention further assumes that the solidified Thread from the winding machine with constant, high Speed is subtracted automatically around you moving air jacket. This drag air cannot prevent but be used. So instead of narrowing the thread exit and the Extracting all air from the duct is invented suggested that after exiting the shaft (B) in the Cross section constant, but very tight end shaft (C) connect in which the threads should remain as long as possible. The not only does this prevent constant air flow Inflow of false air, but still supported by the The aforementioned drag air pulls the suction on the air inflow and relieves it the cost of generating suction air.

The process engineering benefit of the invention lies primarily in the Possibility of higher spinning speeds than conventional ones To achieve processes with purely mechanical means. Also the Task compared to the known EP patent 0 682 720 better and solved cheaper.

Fig. 1 zeigt schematisch ein erfindungsgemäßes Kühlsystem, links einen Schnitt durch den Fadenlauf von der Spinndüseneinheit bis zur Aufspulung und rechts die Ansicht auf einen beispielhaften Aufbau mit sechs Fadenläufen.

Fig. 2 zeigt links den Fadenlauf in einem konventionellen Kühlschacht mit Querstromanblasung und den vertikalen Geschwindigkeitsverlauf der Gesamtluft und rechts im Diagramm die Filamentgeschwindigkeit und dazu die Geschwindigkeit der unmittelbaren Begleitluft des Fadens.

Fig. 3 zeigt links den Fadenlauf in einem erfindungsgemäßen Kühlschacht mit Gleichstromführung und den vertikalen Geschwindigkeitsverlauf der Gesamtluft und im Diagramm rechts die Filamentgeschwindigkeit und die Geschwindigkeit der unmittelbaren Begleitluft des Fadens.

Fig. 4 zeigt ein erfindungsgemäßes Beispiel für sechs Fäden in dreidimensionaler Darstellung.

The further description is based on the drawings, in which:

1 schematically shows a cooling system according to the invention, on the left a section through the thread run from the spinneret unit to the winding and on the right the view of an exemplary structure with six thread runs.

Fig. 2 shows on the left the thread run in a conventional cooling shaft with cross-flow blowing and the vertical speed profile of the total air and on the right in the diagram the filament speed and the speed of the direct accompanying air of the thread.

Fig. 3 shows on the left the thread run in a cooling shaft according to the invention with direct current guidance and the vertical speed profile of the total air and in the diagram on the right the filament speed and the speed of the direct accompanying air of the thread.

4 shows an example according to the invention for six threads in a three-dimensional representation.

In Fig. 1, a process structure according to the invention is purely schematic shown. The thread run (3a, 3) of the Spinning nozzle unit (1) up to the winding (2) and on the right the View for an exemplary setup with six spinneret units (1) shown. The width of the first shaft (A) is constant, i. H. the two side walls (4) are straight and parallel to each other executed, and the taper takes place only through the front and back walls (5a, 5b) of the shaft. The thread path (3a) is easily out of the Vertically clamped so that the start-up in the preparation oiler (6) can be guaranteed. Front and rear wall (5a, 5b) of the shaft are inclined evenly towards the middle of the thread, so that the bevel must be done asymmetrically. The individual are on the right in the view Fenders or partitions (7) shown the identical conditions between the individual filament bundles (3a) in this area subtracted parallel to each other. At the bottom of the First shaft (A) are the preparation oilers (6), which are for different titers must be adjustable in height, and then the first thread guides (8) directly before the transition to the next one Shaft (B) housed. Since the filament bundle (3) in the present Example wound separately, there is only a small one Tapering of the shaft B via its front and rear walls (9a, 9b). The width of the shaft (B), however, remains constant, the side walls (10) parallel to each other. The air extraction (11) takes place shortly before the end of the second shaft (B) by means of a suction fan (11a), and the Air is then returned to the spinneret units (1) already tempered (because driven in a circle) close to the thread over one Blow ring (12) introduced and evenly on the Spinneret units (1) to be distributed. More air volumes will be at the upper open beginning of the first shaft (A) through the gap (13) sucked in if necessary. At the transition from the second shaft (B) to the End shaft (C) are attached to the second thread guides (14) can also be omitted if necessary. Basically, the Air extraction (11) also in the extraction direction further down from shaft C be made. However, the danger is more undesirable False air intake, the smaller the distance between Air extraction (11) and the outlet end (18) of shaft C. The The shaft (C) is constant in cross section, but is kept very narrow, so the constant air flow created here the inflow of False air is prevented and extends until shortly before the first extraction godet (17) or in the case of spinning without godets until shortly before the next one Spinning element, for example the winder (2). The is preferably Distance between filament bundles and the walls (15a, 15b) of Shaft (C) 1 to 4 cm.

Fig. 2 shows schematically the thread path (3a, 3) in one on the left conventional cooling shaft and the vertical speed curve of the total air, which is blown transversely downwards very slowly flows. The filament speed is entered on the right in the diagram, the from the injection speed (V1) to the Winding speed (V2) increases in order to then remain constant. Nearly in parallel, the speed of the immediate accompanying air increases, generated only by the pull of the thread, its course.

In comparison, FIG. 3 shows the schematic thread path on the left (3a, 3) in shaft A and B of a cooling system according to the invention and vertical speed curve of the guided in direct current Total air. Here, the extraction is forced into the vertical moving air due to the tapering of the cooling shaft A as a whole accelerated. The speed course of the filament and the Speed of the direct accompanying air of the thread is in the Diagram shown on the right. Because accelerated air movement is present, the thread (3a, 3) needs its immediate accompanying air not to accelerate as much as with conventional thread cooling. That is, the filament speed of the non-solidified polymer (3a) is not braked as much as usual in the prior art, and the Freezing point of the filaments or the first thread guide (8) lies further away from the spinneret unit (1). Through this gentle Elongation, in a longer period of time than usual, can cause Take-off speed can be increased without causing thread breakage.

4 shows another example according to the invention for six commonly wound filament bundles (3) in three dimensions Presentation. The width of the first shaft (A) is constant and designed according to the spinning arrangement. Between each Filament bundles (3a) separating plates (7) are positioned so that for each of these bundles of threads (3a) the same space is available. The The height of the shaft (A) is usually 1.8 to max. Be 2.2 m, according to the level of the spinning platform. The two side walls (4) are straight and parallel to each other and the taper of a total of 10 ° to max. 30 ° only overlaps laterally, the front and Rear wall (5a, 5b) of the shaft instead. The front wall (5a) can be folded executed, the hinges of the hinged doors (19) for a vertical vertical opening are provided. The doors (19) have in the area of Lubricator arrangement (6) Viewing window (20) for process monitoring on the lubricator (6) and first thread guide (8). In the drawing is the left door (19) shown open. The taper in the second shaft (B) is true freely selectable, but mostly on the side and as short as possible building so that the threads (3) can be carried on to save space, d. H. here the dimensioning results more or less from the structural conditions of the plant. Generally there is an angle of 2 up to 30 ° between the front and rear wall (9a, 9b) and from 30 to 120 ° between the two side walls (10) appropriate. Air extraction (11) takes place shortly before the end of the shaft (B) via an adapted Pipe system. The return of the air to the spinning position is here Not shown. The subsequent end shaft (C) is in cross section kept constant, but it should be as tight as still manageable, and also be as long as possible. A single door (21) is provided here, which extends into the area at the transition of the second shaft (B), so that the second thread guides (14) can be operated.

Claims (10)

1. A cooling system for filament bundles which are spun from polymer melt by at least two spinneret units (1) arranged one beside the other and are drawn off by a draw-off system at a speed of ≥ 1000 m/min, the filament bundles being cooled by an equidirectional stream of air, characterised in that the cooling system consists of the following parts:

   directly below the spinneret units (1) means (12, 13) for supplying air, adjoining these, a shaft A of rectangular cross-section, constant width between the side walls (4) of the shaft, and a depth tapering in the draw-off direction between the front and rear wall (5a, 5b) of the shaft, the filament bundles (3a) being drawn off through the shaft A and near the exit from shaft A being first of all guided over a lubrication oiler (6) and thereafter through a first thread guide (8),

   a shaft B, adjoining the shaft A, of rectangular cross-section and of a depth tapering in the draw-off direction and optionally of a tapering width, the filament bundles (3) being drawn off through the shaft B,

   a shaft C, adjoining the shaft B, of rectangular, constant cross-section, which extends to near the draw-off system (17), the filament bundles (3) being supplied to the draw-off system (17) through the shaft C, and

   close to the exit from the shaft B means (11) for discharging air.
2. A cooling system according to Claim 1, characterised in that one partition (7) each is arranged inside the shaft A between two filament bundles (3a) each, which partition extends over the entire depth of the shaft A parallel to the side walls (4) thereof.
3. A cooling system according to Claim 1 or 2, characterised in that the front and rear walls (5a, 5b) of the shaft A are arranged at an angle of 10 to 30° to each other, both walls (5a, 5b) being uniformly inclined towards the axis of the filament bundles (3a).
4. A cooling system according to Claim 3, characterised in that the angle between the front and rear walls (5a, 5b) can be variably adjusted, the adjustment being made such that inside the shaft A the flow rate of the supplied air increases approximately to the same extent as the speed of the filament bundles (3a).
5. A cooling system according to one of Claims 1 to 4, characterised in that the distance between the filament bundles (3) and the walls (15a, 15b, 16) of shaft C is 1 to 4 cm.
6. A cooling system according to one of Claims 1 to 5, characterised in that the cross-section of shaft B tapers in depth and in width, the filament bundles (3) being guided through a second thread guide (14) close to the exit from shaft B.
7. A cooling system according to Claim 6, characterised in that the front and rear walls (9a, 9b) of the shaft B extend at an angle of 2 to 30°, and the two side walls (10) at an angle of 30 to 120° to each other.
8. A cooling system according to one of Claims 1 to 7, characterised in that the front wall (5a) of the shaft A and/or the front wall (15a) of the shaft C can be opened.
9. A cooling system according to one of Claims 1 to 8, characterised in that the means for supplying air consists of a gap (13) between shaft A and the spinneret units (1) which is open towards the ambient air, and the means for discharging air consists of at least one line (11) with exhauster (11a), which line branches off from shaft B.
10. A cooling system according to Claim 9, characterised in that the means for supplying air additionally comprises a blow ring (12) which opens into the gap (13) and surrounds the at least two spinneret units (1), the air discharged by means of the at least one exhauster (11a) being recirculated to the blow ring (12) and being uniformly distributed over the at least two spinneret units (1).

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