Device for cooling a ring-shaped extruded filament strip

Abstract

Device for cooling a ring-shaped extruded filament strip with a hollow cylindrical blowpipe (1) having a gas-permeable jacket (1.1), with a conically shaped pipe support (3) having a conical cavity (3.1) and a lateral connection nozzle (4) for supplying cooling air, wherein the blowpipe (1) is attached to an upper end of the pipe support (4) and is connected to the cavity (3.1), characterized in that the connection nozzle (4) and the pipe support (3) are designed to interact in such a way that a cyclone-shaped airflow can be generated in the cavity (3.1) of the pipe support (3).

Description

[0001] The invention relates to a device for cooling a ring-shaped extruded filament sheet according to the preamble of claim 1.

[0002] A generic device is known, for example, from US 2004 / 0 032 048 A1.

[0003] When melt spinning filament strands, it is common for the freshly extruded filaments to be cooled by cooling air to solidify them. For this purpose, the cooling air can be directed transversely to the filament strands, or radially from the inside out, or radially from the outside in. To uniformly cool a large number of filaments with a cooling air stream, devices of this type are preferred, in which a cooling air stream penetrates the filament strands radially from the inside out. For this purpose, elongated blowpipes are used, which have a gas-permeable jacket and thus generate a cooling air stream across the jacket surface.

[0004] As is known from US 2004 / 0 032 048 A1, the cooling air must be supplied at one end of the blowpipe. For this purpose, conical tube supports are preferably used. These are connected to an open end of the blowpipe and have a lateral connection piece for supplying the cooling air. The conical shape of the tube support is due to the filament guide, which is usually combined into a fiber strand after cooling and thus converges towards a convergence point. Due to the strong deflection of the cooling air supply via the connection piece and the tube support, eddies and turbulence are unavoidable when supplying the cooling air to the blowpipes. In order to achieve a relative homogenization of the supplied cooling air, the known device has several flow dividers that are assigned to the inlet of the blowpipe within the tube support.However, this does not affect the filling and distribution of the blowing air within the blowpipe. The connecting piece extends the entire length of the pipe support, resulting in an uneven deflection of the supplied cooling air due to the conicity of the pipe support. This leads to speed differences in the cooling air supply and extends over the circumference of the blowpipe due to an inhomogeneous speed distribution of the air flow.

[0005] It is now an object of the invention to provide a generic device for cooling a ring-shaped extruded filament sheet, in which the blowpipe generates an air flow that is as homogeneous as possible for cooling the filaments.

[0006] A further aim of the invention is to intensify the supply of cooling air into the blowpipe.

[0007] This object is achieved in that the connecting piece and the pipe support are designed to interact in such a way that a cyclone-shaped air flow can be generated in the cavity of the pipe support.

[0008] Advantageous further developments of the inventions are defined by the features and combinations of features of the subclaims.

[0009] The invention is characterized by the fact that a forced vertical air flow develops within the tube support, resulting in an intensive and uniform supply of cooling air into the blowpipe. The constantly supplied cooling air forces the already rotating air inside the tube support downwards and accelerates due to the tapered shape of the cavity. At the lowest point of the tube support, the cooling air reverses and flows upwards in the center as a vortex. The vortex flow rises into the blowpipe and exits through the blowpipe casing. The exit velocity is uniform across the circumference of the casing surface, thus ensuring even cooling of the filaments.

[0010] To generate the cyclone-shaped air flow within the pipe support, a particularly effective development of the invention is one in which a guide means is assigned to the connecting piece in the hollow space of the pipe support, through which a sheath flow can be generated by air inlet. This allows the cooling air to be directed in a forced flow direction to achieve the desired cyclone-shaped flow pattern inside the pipe support.

[0011] In order to avoid undesired eddies or turbulences when the cooling air enters the hollow space of the pipe support, the guide means extends over an entire cross-section of a connection opening of the pipe support and is arranged in an upper area of ​​the pipe support.

[0012] To intensify the cyclone flow, the development of the invention is particularly advantageous in which the cavity within the pipe support is conical and in which the blowpipe opens into the cavity centrally on a circular surface of the pipe support. This creates, on the one hand, a substantially vertically rising vortex flow that enters the center of the blowpipe.

[0013] To support the formation of the sheath flow when the cooling air enters the hollow space of the pipe support, a further development of the invention is provided in which the blowpipe dips into the hollow space of the pipe support with a closed lower pipe end, and in which the connecting piece opens into an annular space formed by the pipe support and the blowpipe. Thus, the entire cooling air supplied is initially introduced in a sheath-like manner into the annular space between the blowpipe and the pipe support.

[0014] In order to parallelize and homogenize the rising vortex flow within the tube support upon entering the blowpipe, a particularly advantageous development of the invention is one in which one or more internal flow guide elements are assigned to the end of the blowpipe. For example, sheets with a honeycomb structure could be used as flow guides.

[0015] Alternatively, it is also possible to arrange a metal foam inside the end of the blowpipe in order to achieve intensive homogenization of the vortex flow.

[0016] To even out the sheath flow in the upper region of the blowpipe, a further development of the invention is provided, in which the blowpipe has an internal flow divider at a closed upper end. Conical guide elements are preferably used as the flow divider to achieve a uniform flow distribution.

[0017] In the production of staple fibers, a further development of the invention has proven particularly successful, in which a preparation device is arranged in the upper region of the tube support, which has at least one annular wetting agent. This allows all filament strands to be wetted directly after cooling and then combined to form a tow.

[0018] The device according to the invention thus has the particular advantage of generating a centric vortex flow through the forced and guided air flow within the pipe support, which generates a uniform exit velocity within the blowpipe over the circumference of the casing of the blowpipe.

[0019] The invention is explained in more detail below using some embodiments with reference to the attached figures.

[0020] They represent: Fig. 1 schematically shows a longitudinal sectional view of a first embodiment of the device according to the invention for cooling a ring-shaped extruded filament sheet Fig. 2 schematically shows a cross-sectional view of the embodiment of Fig. 1 Fig. 3 schematically shows a further embodiment of the device according to the invention for cooling a ring-shaped extruded filament sheet Fig. 4 schematically shows a cross-sectional view of the embodiment of Fig. 3

[0021] In the Fig. 1 and Fig. 2, a first embodiment of the device according to the invention for cooling a ring-shaped extruded filament sheet is shown schematically in several views. Fig. 1 shows the embodiment in a longitudinal section and in Fig. Figure 2 shows the embodiment in a cross-sectional view. Unless explicitly referenced to one of the figures, the following description applies to both figures.

[0022] The embodiment of the device according to the invention comprises an elongated blowpipe 1. The blowpipe 1 has an upper, closed pipe end 1.2. An opposite, open pipe end 1.3 is arranged at an upper end of a pipe support 3. The longitudinal section of the blowpipe 1 outside the pipe support 3 has a gas-permeable casing 1.1, which can be made of a fabric, for example. The open pipe end 1.3 of the blowpipe 1 protrudes with a closed cylindrical wall 1.4 into a conical cavity 3.1 of the pipe support 3. At the opposite, closed pipe end 1.2, a flow divider 2 is arranged within the blowpipe 1. The flow divider 2 is conical and arranged essentially concentrically with the blowpipe 1.

[0023] The pipe support 3 encloses the conical cavity 3.1 with a wall 3.2. The blowpipe 1 is held by a circular support wall 3.3 of the pipe support 3 and extends with the open pipe end 1.3 into the interior of the cavity 3.1. In the area of ​​the pipe end 1.3, an annular space 3.5 is formed between the blowpipe 1 and the pipe support 3. In the area of ​​the annular space 3.5, the pipe support 3 has a lateral connection opening 3.4, at which a connection piece 4 is arranged. A guide means 5 is assigned to the connection piece 4 within the cavity 3.1. The guide means 5 extends over an entire cross-section of the connection opening 3.4 and has a curvature inclined towards the wall 3.2. This situation is particularly Fig. 2 shown.

[0024] As further stated Fig. 2, the connecting piece 4 has a cross-sectional constriction compared to the pipe support 3.

[0025] To ensure the function of the Fig. 1 and Fig. To explain the embodiment shown in Figure 2, a cooling air flow is indicated by arrows.

[0026] During operation, the blowpipe 1 is arranged centrally below a ring spinneret. The ring spinneret has a plurality of nozzle openings which extrude a uniformly distributed ring-shaped sheet of filaments. For cooling, cooling air is supplied to the exemplary embodiment via the connecting piece 4. The cooling air is only supplied to the upper region of the tube support 3 and is deflected into a jacket flow by the guide means 5 immediately upon entering the cavity 3.1. Due to the conical or preferably tapered design of the cavity 3.1 within the tube support 3, the cooling air is guided spirally from the annular space 3.5 into the lower region of the cavity 3.1. This creates a cyclone-shaped air flow which generates a central, vertically ascending vortex flow. This vortex flow enters the open tube end 1.3 of the blowpipe 1 and rises up within the blowpipe 1. In the process, a vortex formed on the circumference of the jacket 1.1 uniform cooling air flow is generated.

[0027] In order to achieve a homogenization of the vortex flow within the blowpipe 1, one or more flow guide elements 7 can optionally be arranged within the open pipe end 1.3 of the blowpipe 1. Fig. 1 shows several flow guide elements 7 in dashed lines as an example. The flow guide elements 7 can be formed, for example, by honeycomb-shaped metal sheets.

[0028] In order to create a jacket-shaped inlet flow of cooling air in the upper area of ​​the pipe support 3, it is also possible to arrange the connection piece 4 as tangentially as possible to the pipe support 3. For this purpose, Fig. 3 shows a further embodiment of the device according to the invention for cooling a ring-shaped extruded filament sheet in a longitudinal sectional view. Fig. 4 shows a cross-sectional view of the embodiment of Fig. 3. In this case too, the following description applies to both figures, unless an explicit reference is made to one of the figures.

[0029] The Fig. 3 and Fig. The embodiment shown in Figure 4 is essentially identical to the aforementioned embodiment according to Fig. 1 and Fig. 2, so that at this point only the differences are explained and otherwise reference is made to the above description.

[0030] In the Fig. 3 and Fig. In the embodiment shown in Figure 4, a preparation device 8 is arranged in the upper region of the tube support. The preparation device 8 has a wetting agent 8.1, which is connected to a fluid source via lines not shown here. The wetting agent 8.1 is arranged on the tube support 3 such that a sheet of filaments guided annularly around the blow tube 1 is wetted with a fluid by the wetting agent 8.1 after cooling. In this respect, the filaments are guided in contact with the wetting agent 8.1.

[0031] The information contained in the presentation in Fig. 4, the pipe support 3 and the connecting piece 4 are arranged at an angular position relative to each other such that a cooling air flow supplied through the connecting piece 4 through the connection opening 3.4 enters the cavity 3.1 or the annular space 3.5 essentially tangentially. The flow path of the cooling air is shown in Fig. 4 is shown schematically with arrows. In this respect, the function for supplying and generating a cyclone-shaped vortex flow in the embodiment according to Fig. 3 and Fig. 4 identical to the embodiment according to Fig. 1 and Fig. 2. In this respect, reference is made to the above description.

[0032] In the Fig. 3 and Fig. In the embodiment shown in Figure 4, the swirling flow is evened out by a metal foam 6 upon entering the open end 1.3 of the blowpipe 1. The cooling air must pass through a labyrinth of metallic pores, which, in particular, also leads to the evening out of temperature differences in the cooling air. Furthermore, pressure fluctuations and volume fluctuations of the cooling air before entering the blowpipe can be advantageously evened out.

[0033] The device according to the invention is particularly suitable for cooling the filament strands produced in a one- or two-stage process for the production of staple fibers. Filaments in the linear density range of 0.3 to 250 dtex in various polymers can be cooled uniformly.

Claims

[1] Device for cooling a ring-shaped extruded filament sheet with a hollow cylindrical blowpipe (1) having a gas-permeable casing (1.1), with a conically shaped pipe support (3) having a conical cavity (3.1) and a lateral connection piece (4) for supplying cooling air, wherein the blowpipe (1) is attached to an upper end of the pipe support (4) and is connected to the cavity (3.1), characterized by that the connecting piece (4) and the pipe support (3) are designed to interact in such a way that a cyclone-shaped air flow can be generated in the cavity (3.1) of the pipe support (3). [2] Device according to claim 1, characterized in that a guide means (5) is assigned to the connecting piece (4) in the cavity (3.1) of the pipe support (3), by means of which a sheath flow can be generated when air enters. [3] Device according to claim 2, characterized bythat the guide means (5) extends over an entire cross-section of a connection opening (3.4) on the pipe support (3) and is arranged in an upper region of the pipe support (3). [4] Device according to one of claims 1 to 3, characterized by that the cavity (3.1) within the pipe support (3) is conical and the blow pipe (1) opens into the cavity (3.1) centrally to a circular support wall (3.3) of the pipe support (3). [5] Device according to one of claims 1 to 4, characterized by that the blow pipe (1) with a lower open pipe end (1.3) is immersed in the cavity (3.1) of the pipe support (3) and that the connecting piece (4) opens into an annular space (3.5) formed by the pipe support (3) and the blow pipe (1) in the cavity (3.1). [6] Device according to claim 5, characterized by that one or more internal flow guide elements (7) are assigned to the open pipe end (1.3) of the blow pipe (1). [7] Device according to claim 5, characterized by a metal foam (6) arranged within the open pipe end (1.3) of the blow pipe (1). [8] Device according to one of claims 1 to 7, characterized by that the blowpipe (1) has an internal flow divider (2) at an upper closed pipe end (1.2). [9] Device according to one of the preceding claims, characterized by that in the upper region of the pipe support (3) a preparation device (8) is arranged, which has at least one annular wetting agent (8.1).

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