Apparatus for melt spinning and cooling freshly extruded filament pieces

Abstract

The invention relates to a device for melt-spinning and cooling of freshly extruded filament pieces, having at least one spinneret unit held on the underside of a spinning beam. Below the spinneret unit there is provided at least one hollow-cylindrical cooling cylinder having a gas-permeable cylinder wall and extending within an air chamber between a filament inlet and a filament outlet. Between the filament inlet of the cooling cylinder and the spinneret unit there is provided a connection piece having a filament channel, which connection piece has at least one ventilation duct opening into the filament channel. In order to achieve a preliminary cooling of the filament threads in the filament channel between the spinneret unit and the cooling cylinder, according to the invention the ventilation duct of the connection piece is assigned a closure mechanism by means of which the passage cross section available in the ventilation duct can be adjusted.

Description

TECHNICAL FIELD

[0001] The invention relates to an apparatus for melt spinning and cooling of freshly extruded filament pieces. BACKGROUND

[0002] It is generally known in the production of synthetic yarns to extrude a plurality of elongated filament strands from a polymer melt through a plurality of orifices of a spinning nozzle unit. The filament strands are formed into a bundle here, which after cooling is collected to form a yarn. In order for the filament strands not to bond within the yarn structure, each filament strand within the bundle must be cooled after extrusion in order for the filament strands to solidify. In order to cool the filament strands, a cooling air flow is generally generated which acts on the filament strands. However, it is required here that a uniform cooling and in turn a uniform solidification take place ideally on each filament strand within the bundle.

[0003] A plurality of apparatuses for melt spinning and cooling of freshly extruded filament pieces are disclosed in the prior art, the apparatuses for generating a cooling air flow can be essentially divided into a plurality of groups. In a first group, known for example from DE 44 04 258 Al, for example a transverse cooling air flow is directed at the extruded filament strands. To this end, a blower wall which is connected to a blower chamber in which conditioned air is conveyed and impinges on the filaments transversely by means of a blower, extends in the direction of movement of the filaments. However, this apparatus, also referred to as transverse flow quenching, has the essential disadvantage that the filament bundle is impinged on by the cooling air flow only from one side.

[0004] In order to direct the cooling air flow to the filament bundle from all sides, a second, generally known type of melt spinning apparatus is known, in which the filament bundle is guided in a hollow-cylindrical cooling cylinder having a gas-permeable cylinder wall and arranged in an air chamber upon extrusion. A transversely directed cooling air flow can thus be generated all around the filament bundle. This cooling is also referred to in the industry as radial quenching and is described for example in US 5 219 582.

[0005] Both the transverse flow quenching and the radial quenching are based on a substantially transversely directed cooling air flow which is directed at the generated filament strands. In this regard, it is necessary for the filament strands to already have a sufficient degree of preliminary solidification upon impingement by the cooling air so that any cross-sectional changes, in particular with respect to the outer filament strands, are not obtained upon impingement by the cooling air. In order to obtain a delayed cooling of the filament strands, it is therefore also known to generate a transition zone on the low side of the spinning nozzle unit by means of a connection between the spinning nozzle unit and the cooling cylinder. This transition zone, which cannot be cooled, has proven to be an important parameter for the yarn quality to be optimized in the spinning process. It is desirable here to be able to design this transition zone as flexibly as possible.

[0006] A melt spinning and cooling device of this type with such a transition zone is known, for example, from WO 2016 / 174828 A1, from which the present invention starts. Here, the transition zone is used to discharge exhaust air formed when extruding a specific type of polymer into the environment. The connection piece thus has a ventilation duct which opens into the transition zone. SUMMARY

[0007] In view of a device of this type for melt spinning and cooling of just extruded filament pieces, it is now the object of the present invention to be able to use the transition zone between the spinning nozzle unit and the cooling cylinder as flexibly as possible to influence the cooling of the filament threads.

[0008] According to the invention, this object is achieved in that the ventilation duct of the connection piece is assigned a closing mechanism by means of which the passage cross section available in the ventilation duct can be set.

[0009] The invention has the particular advantage that the transition zone between the filament thread outlet on the underside of the spinning nozzle and the inlet into the cooling channel, which is also referred to in the industry as the so-called shroud, can advantageously be used to obtain a more or less intensive cooling effect or a delayed cooling of the filament threads, respectively. The mass flow rate of the output cooling air or the input ambient air can advantageously be controlled by changing the passage cross section available in the ventilation duct. Changing the mass flow rate by changing the passage cross section of the ventilation duct is particularly advantageous, especially in the case of different thread counts.

[0010] This effect can be further improved in that, according to an advantageous refinement of the invention, the connection piece has a plurality of air passages which are designed on the connection piece to be distributed at a mutual distance in the region between the spinning nozzle and the cooling cylinder. Thus, additional air for initially cooling the filaments in the transition zone can be admitted to enter or exit in the manner of a cooling cylinder over the entire peripheral surface.

[0011] However, the following ventilation duct arrangement is particularly advantageous, in that the ventilation ducts according to an advantageous refinement of the invention are stacked one above the other along a vertical line on the connection piece. Thus, the length of the transition zone between the spinning nozzle and the cooling cylinder can be changed with or without additional cooling air. The transition zone between the spinning nozzle and the cooling cylinder can thus be used flexibly to cool the filaments with or without the use of an additional cooling air supply or with only a part of the amount of additional cooling air.

[0012] In order to change the passage cross section available in the ventilation duct, according to an advantageous refinement of the invention, a plurality of closing mechanisms can be provided in such a way that each ventilation duct can be individually adjusted with regard to the cross section available.

[0013] In order to change only the length of the transition zone with the additional supply of cooling air, the following improvement of the application has proved successful, the ducts are assigned a common aperture by means of which the total cross section of the ducts resulting from the sum of the individual duct cross sections can be adjusted. The vertically overlapping arrangement of the ducts designed in the connection can thus be opened in succession.

[0014] For this purpose, the aperture is preferably guided by means of a push-through mechanism. For example, the lowermost duct facing the cooling cylinder can thus be opened first. For example, the yarn with the small number of filaments can thus be extruded with the closed total channel cross section, and the yarn with the large number of filaments can then be extruded with the partially or even completely opened total channel cross section.

[0015] According to an advantageous improvement of the application, the air chamber is connected to an air conditioning air generator or to a negative pressure generator. Different cooling effects can thus be achieved on the filament thread. When the air chamber is connected to an air conditioning air generator, the air conditioning cooling air can be directed radially from the outside to the inside by means of the cooling cylinder to the filament thread, so that the outflow of the cooling air flow is in the same direction as the filament run. By means of the adjustability of the ducts on the connection, a part of the cooling air can then flow counter to the filament movement direction.

[0016] When a negative pressure generator is used, the cooling air is preferably sucked through the outlet of the cooling cylinder and directed radially from the inside to the outside into the air chamber at the cooling cylinder. In this regard, a cooling air flow counter to the filament movement direction is generated, which improves the cooling effect in particular. However, by means of the adjustability of the ducts within the connection, an additional cooling air flow in the direction of the filament thread movement can be generated.

[0017] For this purpose, the filament channel within the connection is directly connected to the environment by means of the duct or the ducts.

[0018] When an air conditioning air generator is used, the following improvement of the application has also proved successful, the duct is connected to a suction device for discharging the consumed cooling air, or a plurality of ducts are connected to a suction device for discharging the consumed cooling air. In order to extrude the generated vapors and exhaust gases are thus also advantageously discharged and intercepted by means of the duct.

[0019] In order to achieve a uniform air flow over the entire length of the cooling cylinder, the following improvement of the application has proved to be successful, the air chamber is coaxially assigned a low air distribution chamber, the air chamber and the air distribution chamber are connected by a perforated metal sheet, the air distribution chamber is penetrated by a tubular port in the filament outlet region of the cooling cylinder and the air distribution chamber has a connection for the air conditioning air generator or for the negative pressure generator. The supply of cooling air or the discharge of cooling air used is thus guided through the air distribution chamber. The air distribution chamber is connected to the air chamber in the vertical direction by the perforated metal sheet, so that no radially directed forced flow in the air chamber is produced by the supplied or discharged cooling air.

[0020] The device for melt spinning and cooling of freshly extruded filament pieces according to the application is used for the production of yarns and can be used here for the production of yarns with small filament counts or even with large filament counts with uniformization of the filament threads cooling. BRIEF DESCRIPTION OF DRAWINGS

[0021] In the following, several embodiments of the device for melt spinning and cooling of freshly extruded filament pieces according to the application are explained in more detail with reference to the drawings. In the drawings:

[0022] Figure 1 schematically shows a cross-sectional view of a first embodiment of the device for melt spinning and cooling of filament pieces according to the application;

[0023] Figure 2 schematically shows a cross-sectional view of a further embodiment of the device for melt spinning and cooling of filament pieces according to the application;

[0024] Figure 3 schematically shows a cross-sectional view of a first embodiment of the device for melt spinning and cooling of filament pieces according to the application;

[0025] Figure 4 schematically shows a cross-sectional view of a first embodiment of the device for melt spinning and cooling of filament pieces according to the application;

[0026] Figure 5 schematically shows a cross-sectional view of a first embodiment of the device for melt spinning and cooling of filament pieces according to the application; and

[0027] Figure 6 schematically shows a cross-sectional view of a first embodiment of the device for melt spinning and cooling of filament pieces according to the application. DETAILED DESCRIPTION

[0028] Figure 1 schematically shows a cross-sectional view of a first embodiment of the device for melt spinning and cooling of filament pieces according to the application. However, Figure 1Only the main components of the device according to the application are shown which are relevant for the explanation of the application. Since such a device for melt spinning and cooling of freshly extruded filament pieces is generally known, a complete description is dispensed with.

[0029] Figure 1 The shown embodiment has a spinning nozzle unit 1 which carries a nozzle plate 1.1 with a plurality of nozzle openings 1.2 on the underside. The spinning nozzle unit 1 is held in a heated spinning beam 2 and has a melt inlet, not shown here, for accommodating a polymer melt.

[0030] A cooling cylinder 3 is arranged below the spinning nozzle unit 1 in essentially coaxial manner to the nozzle plate 1.1. The cooling cylinder 3 has an upper filament inlet 3.1 and a filament outlet 3.2 at the lower end. The cooling cylinder 3 extends within an air chamber 4 by means of a gas-permeable cylinder wall 3.3. The air chamber 4 encloses the cooling cylinder 3 in housing-like manner and is enclosed with respect to the environment by means of a wall 4.1. An air distribution chamber 5, separated from the air chamber 4 by a perforated metal plate 7, adjoins the air chamber 4 on the underside. The air distribution chamber 5 is penetrated by a tubular port 6 which adjoins the filament outlet 3.2 of the cooling cylinder 3 in coaxial manner to the cooling cylinder 3. The air distribution chamber 5 has a lateral air connection opening 8 which is joined to an air connection 9. An air conditioning air generator 10 is connected to the air distribution chamber 5 by means of the air connection 9.

[0031] A connection 11 is arranged in the region between the spinning nozzle unit 1 and the cooling cylinder 3. The connection 11 is held on the underside of the spinning beam 2 and is supported on the upper side of the air chamber 4 by means of a seal 16. The air chamber 4 and the air distribution chamber 5 are enclosed with respect to the environment by means of the chamber walls 4.1 and 5.1. The connection 1 forms a filament channel 12 which is held in concentric manner to the nozzle plate 1.1 of the spinning nozzle unit 1. The filament channel 12 thus forms a transition zone between the underside of the spinning nozzle unit 1 and the cooling cylinder 3.

[0032] A ventilation duct 13 is arranged on the connection 11. The ventilation duct 13 opens into the filament channel 12 and communicates the filament channel 13 to the environment. A closing mechanism 14 of the available passage cross section of the ventilation duct 13 can be adjusted thereby is arranged within the ventilation duct 13. The passage cross section of the ventilation duct 13 can thus be individually opened and closed in any intermediate position by means of the closing mechanism 14.

[0033] The device for melt spinning and cooling according to the application is shown in Figure 1is shown in the working condition, at which the polymer melt is extruded through the spin- nozzle unit 1 to form a plurality of filament threads 15. The filament threads 15 are extruded through the nozzle openings 1.2 of the nozzle plate 1.1 and enter the cooling cylinder 3 via the filament channel 12. Air-conditioning air, which has already entered the air chamber 4, continuously penetrates in a radial manner from the outside to the inside via the air-permeable cylinder wall 3.3 of the cooling cylinder 3. In the case of an open or partially open passage cross-section of the ventilation duct 13 within the connecting piece 11, a portion of the air-conditioning air is directed in the upper-side region of the cooling cylinder 3 counter to the air direction of the filament threads 14 from the filament inlet 3.1, which air-conditioning air is then discharged to the environment through the ventilation duct 13. An additional preliminary cooling of the filament threads can then be obtained by means of the counterflow.

[0034] But alternatively, a suction device 18 can also be connected at the outlet end of the ventilation duct 13. The suction device 18 is for this purpose connected to the air chamber 4 via the air connection 9 in Figure 1 . On the one hand, the suction device 18 can receive the cooling air consumed and on the other hand can additionally increase the mass flow. This is thus a further flexibility to be able to use the potential cooling effect in the transition region between the spin- nozzle unit and the cooling cylinder 3.

[0035] In order to obtain an ideal high cooling effect on the filament threads 15, in Figure 2 a further embodiment of a device for melt-spinning and cooling freshly extruded filament pieces according to the application is illustrated in a cross-sectional view. The embodiment according to Figure 2 is identical to the embodiment according to Figure 1 in terms of the structure of the device components, so that only the differences are explained here and reference is otherwise made to the above description.

[0036] In the embodiment shown in Figure 2 , the air distribution chamber 5 is connected to the negative pressure generator 17 by means of the air connection 9. The negative pressure, which is transmitted into the air chamber 4 and causes the cooling air to be sucked, is generated in the air distribution chamber 5 by means of the negative pressure generator 17. Here, the cooling air from the outside is guided into the cooling cylinder 3 through the filament outlet 3.2 by means of the tubular port 6. A cooling air flow is thus generated counter to the direction of movement of the filament threads 15. The cooling air flow is indicated by arrows in Figure 1 and also in Figure 2 .

[0037] Due to the pressure reversal in the air chamber 5, an inwardly directed cooling air flow is generated, which causes the spent cooling air to accumulate in the air chamber 4 and to be discharged through the air distribution chamber 5. The negative pressure effect of the air chamber 4 on the ventilation ducts 13 of the connecting piece 11 generates a cooling air flow which is directed from the outside to the inside. The cooling air is guided through the ventilation ducts 13 into the filament channel 12 and is discharged in the direction of movement of the filament thread 15. Here, the mass flow of the cooling air flow supplied through the ventilation ducts 13 can be individually adjusted by means of the closing mechanisms 14. A preliminary cooling effect on the filament thread in the transition region to the cooling cylinder can thus be achieved.

[0038] In order to be able to design the cooling effect in the transition region between the spinning nozzle unit 1 and the cooling cylinder 3 more flexibly, in Figure 3 a further embodiment of a device for melt-spinning and cooling a filament thread according to the application is shown schematically in a cross-sectional view. According to Figure 3 the embodiment according to Figure 1 is essentially identical to the embodiment according to in order to avoid repetitions, only the differences will be explained here, and reference is otherwise made to the above description.

[0039] Figure 3 In the embodiment shown in Figure 3 the ventilation ducts 13.1 to 13.4 are arranged in a mutually spaced manner between the spinning nozzle unit 1 and the filament inlet 3.1 of the cooling cylinder. The vertically one above the other arranged distribution of the ventilation ducts 13.1 to 13.4 is exemplarily shown in

[0040] . In principle, however, it is also possible to arrange the ventilation ducts 13.1 to 13.4 in one or more planes distributed around the circumference of the connecting piece 11. Each ventilation duct 13.1 to 13.4 is assigned an individual closing mechanism 14.1 to 14.4. The available ventilation duct cross section of the ventilation ducts 13.1 to 13.4 can be variably adjusted by means of the closing mechanisms 14.1 to 14.4.

[0041] Thus, different cooling air effects in the filament channel 12 can be achieved in relation to the opening degree of the ventilation channels 13.1 to 13.4. The ventilation channels 13.1 to 13.4 open into the filament channel 12 and connect the latter to the environment. During operation, the air conditioning air generated by the air conditioning air generator 10 is then partially directed out of the cooling cylinder 3 via the filament inlet 3.1 to the filament channel 12 and, depending on the opening degree, is discharged to the environment through the ventilation channels 13.1 to 13.4. Depending on the distribution of the ventilation channels 13.1 to 13.4 on the connection piece, a more or less preliminary cooling effect can then be generated on the filament thread.

[0042] Figure 3 The embodiment shown can also be operated with a negative pressure generator 17. To this end, Figure 4 A further embodiment of a device for melt spinning and cooling of freshly extruded filament pieces is shown schematically in cross section. According to Figure 4 The embodiment according to Figure 3 The only difference is that a negative pressure generator 17 instead of an air conditioning air generator is connected to the air distribution chamber 5. In this regard, the cooling air sucked through the tubular port 16 is used to cool the filament thread 15. The ventilation channels 13.1 to 13.4 arranged in the connection piece 11 generate a further in-flowing cooling air stream which points from the environment into the filament channel. In relation to the opening degree, an additional cooling effect can be generated here, in which the cooling air flowing into the filament channel 12 is discharged in the direction of movement of the filament thread.

[0043] However, in most cases it is also desirable to vary the transition zone between the spinning nozzle and the cooling cylinder 3 in relation to the polymer type and the number of filaments in terms of the longitudinal extension of the transition zone. The transition zone is also referred to as the so-called cap in the industry. In order to vary the length of the cap, Figure 5 A further embodiment of a device for melt spinning and cooling of freshly extruded filament pieces according to the application is shown schematically in cross section. According to Figure 5 The embodiment according to Figure 3 The embodiment according to

[0044] In Figure 5 In the embodiment shown, a plurality of ventilation channels 13.1 to 13.3 are arranged in the intermediate space between the spinning nozzle 1 and the cooling cylinder 3 on the connection piece 11 in an over-under arrangement on one vertical line. The ventilation channels 13.1 to 13.3 are each spaced apart from one another. The ventilation channels 13.1 to 13.4 open into the filament channel 12. The outlet ends of the ventilation channels 13.1 to 13.4 are closed by a common hole 19. The hole 19 is arranged adjustably by means of a push-fit mechanism 20, so that the ventilation channels 13.1 to 13.3 can be opened one after the other. AsFigure 5 In the illustrated operating condition, all ventilation channels 13.1 to 13.3 are closed. Therefore, no cooling effect occurs within the filament channel 12, causing the filament strands to pass through the filament channel 12 uncooled. The so-called cover has its maximum length in this case. To shorten the cover length, or transition zone length, the hole 19 is shifted, causing the lowest ventilation channel 13 on the connector to open. In this respect, a shortened cover length is formed. The open ventilation channel 13 in the lower region of the filament channel generates a cooling airflow, which results in initial cooling of the filament strands. The transition zone length within the connector 11 can then be altered to obtain a more or less intense cooling effect.

[0045] exist Figure 5 In the illustrated embodiment variant, the air distribution chamber 5 is connected to the air conditioning air generator 10. This generates a radial cooling airflow from the outside to the inside on the cooling cylinder, which is then discharged from the inside to the outside via ventilation ducts 13.1 to 13.3.

[0046] or, Figure 5 The illustrated embodiment can also operate using a negative pressure generator 17. This embodiment... Figure 6 It is shown in the middle. Figure 6 The embodiments described herein differ in structure and function from those based on Figure 5 Similar to the previous embodiment, here the cooling air is directed in the opposite direction. Here, the length of the transition zone and consequently the length of the shroud can also be changed by selectively opening ventilation ducts 13.1-13.3.

[0047] With the help of, as according to Figures 1 to 6 The air distribution chamber shown in the embodiment supplies air to the air chamber, which is exemplary. In principle, the air chamber can also be connected to an air conditioning air generator or a negative pressure generator via an air connector.

[0048] It is also common for this air chamber to contain a number of cooling cylinders, which are distributed to multiple spinning nozzle units on the spinning box. Therefore, the present invention can also be used simultaneously on many spinning units without any problems.

Claims

1. A device for melt-spinning and cooling freshly extruded filament pieces (15), the device having at least one spinning nozzle unit (1) held on the underside of a spinning beam (2) and having at least one hollow-cylindrical cooling cylinder (3) below the spinning nozzle unit (1), the cooling cylinder (3) having a gas-permeable cylinder wall (3.3) and extending within an air chamber (4) between a filament inlet (3.1) and a filament outlet (3.2), and the device having a connection piece (11) with a filament passage (12) between the filament inlet (3.1) of the cooling cylinder (3) and the spinning nozzle unit (1), wherein The connecting piece (11) has a plurality of ventilation channels (13.1-13.4) which open into the filament channel (12), characterized in that the plurality of ventilation channels (13.1-13.4) of the connecting piece (11) are assigned a plurality of closing mechanisms (14.1-14.4) by means of which the passage cross section available in the plurality of ventilation channels (13.1-13.4) can be set in a mutually independent manner, wherein: the plurality of ventilation channels (13.1-13.4) are connected to a suction device (18) for discharging the consumed cooling air, or the air chamber (4) is coaxially assigned a lower air distribution chamber (5), the air chamber (4) and the air distribution chamber (5) are connected by means of a perforated metal plate (7), the air distribution chamber (5) is penetrated by a tubular port (6) in the region of the filament outlet (3.2) of the cooling cylinder (3), and the air distribution chamber (5) has an air connection (9) for a negative pressure generator (17).

2. The apparatus of claim 1, wherein, The plurality of ventilation channels (13.1-13.4) are designed on the connecting piece (11) to be distributed in a mutually spaced manner in the region between the spinning nozzle unit and the cooling cylinder (3).

3. The apparatus of claim 2, wherein, The plurality of ventilation channels (13.1-13.4) on the connecting piece (11) are arranged one above the other along a vertical line.

4. The apparatus of claim 2 or 3, wherein, The plurality of ventilation channels is assigned a common aperture (19) by means of which the total passage cross section of the plurality of ventilation channels resulting from the sum of the individual passage cross sections can be set.

5. The apparatus of claim 4, wherein, The common aperture (19) can be guided by means of a push-through mechanism (20) so that the passage cross section of the plurality of ventilation channels can be opened continuously to open the total passage cross section.

6. The apparatus of any one of claims 1 to 3, wherein, The air chamber (4) is connected to the negative pressure generator (17).

7. The apparatus of claim 2 or 3, wherein, The plurality of ventilation channels (13.1-13.4) connect the filament channel (12) to the ambient environment.

8. The apparatus of claim 1, wherein, When the plurality of ventilation channels (13.1-13.4) are connected to the suction device (18) for discharging the consumed cooling air, the air chamber (4) is coaxially assigned a lower air distribution chamber (5), the air chamber (4) and the air distribution chamber (5) are connected by means of a perforated metal plate (7), the air distribution chamber (5) is penetrated by a tubular port (6) in the region of the filament outlet (3.2) of the cooling cylinder (3), and the air distribution chamber (5) has an air connection (9) for an air conditioning air generator (10).

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