Device for cooling extruded monofilaments

Abstract

This invention relates to an apparatus for cooling extruded monofilaments used in the production of filaments, the apparatus comprising a suction device and at least one cooling cylinder through which the monofilaments are guided. The suction device and the cooling cylinder interact in such a way that a reverse airflow is generated within the cooling cylinder. To avoid the formation of deposits on the cylinder wall, according to the invention, the cooling cylinder has a hollow cylindrical filter element below the monofilament inlet, wherein the filter element rests against an outer, permeable cylinder wall.

Description

Technical Field

[0001] The present invention relates to an apparatus for cooling extruded monofilaments used in the production of filaments. Background Technology

[0002] In the production of synthetic filaments, it is well known that multiple monofilaments are extruded from a polymer melt through numerous nozzle openings in a spinning nozzle. The monofilaments form a bundle, which, upon cooling, aggregates to form a filament. To prevent the monofilaments from connecting with each other within the filament composite structure, each monofilament within the bundle must be cooled after extrusion to allow it to solidify. Cooling airflow is typically generated to cool the monofilaments. However, it is desirable for ideally uniform cooling and therefore uniform solidification to occur on each monofilament within the bundle.

[0003] Various devices for cooling extruded monofilaments are known in the prior art, and these devices differ significantly from each other in the generation of the cooling airflow. Thus, so-called cross-flow blowers and radial flow blowers are known, in which the cooling airflow is guided substantially transversely to the monofilament. The cooling air consumed here is discharged along the direction of the filament's travel. Conversely, devices for cooling monofilaments using a cooling airflow generated opposite to the direction of the monofilament's travel are also known.

[0004] For example, DE 1119456 discloses an apparatus in which a cooling cylinder is directly mounted on a suction device below the spinning nozzle. The monofilament passes through the cooling cylinder, where cooling air enters at the lower end of the cylinder by means of the suction of the suction device, creating a countercurrent within the cylinder. The cooling air consumed here for cooling the monofilament is received by the suction device and cleaned to remove suspended matter. There is a particular risk that waste gas generated during monofilament extrusion can cause deposits on the perforated walls of the cooling cylinder. Therefore, complex cleaning intervals are required to remove this type of deposit from the cooling cylinder. Summary of the Invention

[0005] Now, one object of the present invention is to provide an apparatus for cooling extruded monofilaments by means of a convective airflow, in which consumed cooling air can be drawn in without producing deposits on the wall of the cooling cylinder.

[0006] According to the present invention, this objective is achieved by having a hollow cylindrical filter element in the cooling cylinder below the monofilament inlet, and the filter element being attached to the outer perforated metal plate cylinder wall.

[0007] This invention has a particular advantage in that the cooling air drawn in from the cooling cylinder is filtered before it impacts the permeable cylinder wall. Therefore, suspended particles are filtered from the consumed cooling air before they can settle onto the cylinder wall. Furthermore, pre-cleaning of the drawn-in cooling air is achieved, thus eliminating the need for complex post-treatment procedures.

[0008] The improvement of this invention is particularly advantageous, wherein the replaceable filter element is loosely attached to the cylinder wall and configured to elastically deform through the monofilament inlet. Due to the pressure gradient oriented from the inside to the outside, it is not necessary to fix the filter element to the cylinder wall. The elastic deformation capability of the filter element ensures that it is jacketed against the cylinder wall during operation. The replaceable filter element can now elastically deform in such a way that it can be removed from the monofilament inlet. Therefore, very short downtime can be achieved to allow for filter element replacement.

[0009] Depending on the specific process and application, filter elements can be advantageously formed from open-cell foam materials or filter pads.

[0010] To achieve a uniform suction flow across the entire circumference of the cooling cylinder, it is preferable to implement the improvement of the invention, wherein the cooling cylinder is disposed within a suction chamber and the suction chamber is connected to a suction device. This allows for a uniform airflow that is oriented from the inside out and distributed circumferentially across the cylinder wall and filter element.

[0011] To prevent unfiltered cooling airflow from entering the suction chamber, it is envisioned that the cooling cylinder be provided with an annular seal at the monofilament inlet above the filter element and at the lower end below the filter element, respectively, with the annular seal abutting against the chamber wall of the suction chamber.

[0012] To ideally achieve the cooling section where the reverse airflow for cooling acts on the monofilament, an improvement of the invention is preferably implemented, wherein the cooling cylinder is connected at its lower end to a coaxially disposed pipe fitting, and the pipe fitting forms a monofilament outlet. Cooling air can be uniformly drawn in through the monofilament outlet.

[0013] Synthetic filament production typically takes place at spinning stations, where multiple filaments are produced side-by-side as filament bundles. In this regard, an improvement of the present invention is preferred, wherein the suction chamber has multiple cooling cylinders arranged at intervals from each other. Therefore, reverse airflow can be generated simultaneously on multiple cooling cylinders. The vacuum present throughout the suction chamber acts uniformly on all cooling cylinders. Attached Figure Description

[0014] The apparatus for cooling extruded monofilaments according to the present invention will now be described in more detail with reference to the accompanying drawings and by means of several exemplary embodiments.

[0015] In the attached diagram:

[0016] Figure 1.1 A cross-sectional view of a first exemplary embodiment of the apparatus for cooling extruded monofilaments according to the present invention is shown schematically;

[0017] Figure 1.2 The illustration shows the process of changing the filter element. Figure 1.1 Exemplary embodiments; and

[0018] Figure 2 A cross-sectional view of yet another exemplary embodiment of the apparatus for cooling extruded monofilaments according to the present invention is shown schematically. Detailed Implementation

[0019] Figure 1.1 The diagram schematically illustrates a cross-sectional view of a first exemplary embodiment of an apparatus for cooling extruded monofilaments according to the present invention. This exemplary embodiment includes a cooling cylinder 1 having a permeable cylinder wall 2. The permeable cylinder wall 2 is configured as a hollow cylinder and extends within a suction chamber 5. The upper end of the cooling cylinder 1 has a monofilament inlet 6. The cooling cylinder 1 is sealed relative to the chamber wall 5.2 at the monofilament inlet 6 by an annular seal 4. In this exemplary embodiment, the annular seal 4 is formed of a metal plate profile 4.1 and a seal 4.2. The metal plate profile 4.1 is connected to the cylinder wall 2. A second annular seal 7, also formed of a metal plate profile 7.1 and a seal 7.2, is provided at the lower end of the cooling cylinder 1. The annular seal 7 is supported on the chamber wall 5.2 of the suction chamber 5 in the lower region.

[0020] A hollow cylindrical filter element 3 is disposed inside the cooling cylinder 1 and abuts against the breathable cylinder wall 2. The filter element 3 is formed of an elastically deformable material, such as open-cell foam material or filter pad. In this respect, the filter element 3 can elastically deform and loosely abut against the cylinder wall 2. Figure 1.1 The filter element 3 is shown in the working position and extends between the annular seals 4 and 7.

[0021] The suction chamber 5 encloses the cooling cylinder 1 and has a suction opening 5.1 on one side. The suction opening 5.1 is provided with a suction port 10 connected to the suction device 11. The suction device 11 has a vacuum source 11.1 to generate a vacuum in the suction chamber 5.

[0022] The pipe fitting 8, which remains outside the suction chamber 5, is coaxially positioned at the lower end of the cooling cylinder 1. The lower end of the pipe fitting 8 forms a monofilament outlet 9.

[0023] The suction chamber 5 with cooling cylinder 1 is located below the spinning box during operation, so that the monofilaments generated by the spinning nozzle can enter the cooling cylinder 1 through the monofilament inlet 6. Figure 1.1The spinning nozzle is shown in dashed lines and is marked with reference numeral 14. In this case, the suction device 11 is activated, thereby creating a vacuum in the suction chamber 5, which results in a pressure gradient relative to the environment. Therefore, ambient air for cooling the extruded monofilament is generated through the monofilament outlet 9, which is also shown in dashed lines. The cooling air flows in the opposite direction to the filament's travel direction. Due to the suction effect of the suction chamber 5, the airflow from inside the cooling cylinder 1 is then drawn from the inside to the outside. Here, the air first passes through the filter element 3 and the permeable cylinder wall 2. Here, the cylinder wall 2 can preferably be formed of a perforated metal plate. All suspended matter contained in the air, especially the exhaust gas generated during extrusion, is absorbed here by the filter element 3. Therefore, no deposits are formed on the cylinder wall 2.

[0024] Replacement of filter element 3 is performed after the operating time, which can vary depending on the process. For this purpose, the suction chamber 5, with cooling cylinder 1, is lowered from the lower side of the spinning box during operation via a height adjustment mechanism. The operator can freely access the lowered monofilament inlet 6. The filter element 3, loosely resting against the cylinder wall 2, is now deformed in such a way that it can be removed from the monofilament inlet 6. This situation occurs in… Figure 1.2 The filter element 3 is shown in the diagram. A new filter element 3 is replaced by a new filter element 3. The new filter element 3 is introduced into the cooling cylinder 1 and deformed in such a way that it is uniformly pressed against the cylinder wall 2. During operation, the filter element 3 is pressed against the cylinder wall 2 by suction and pressure gradient in a self-actuating manner. No additional fixing is required.

[0025] exist Figure 1.1 In the exemplary embodiment shown, the suction chamber 5 is directly connected to the suction device 11. In order to achieve uniform suction effect across the entire circumference of the cooling cylinder 1, the connection between the suction chamber 5 and the suction device 11 can also be designed such that a vacuum chamber is first provided between the suction device 11 and the suction chamber 5. Figure 2 An exemplary embodiment for this purpose is shown in the figure. Figure 2 In the exemplary embodiment shown, the vacuum chamber 12 is disposed below the suction chamber 5 and is coaxial with the suction chamber 5. The vacuum chamber 12 encloses the pipe joint 8 connected to the lower end of the cooling cylinder 1. A perforated metal plate 13 is disposed between the suction chamber 5 and the vacuum chamber 12. The vacuum chamber 12 is sealed relative to the environment through the chamber wall 12.1. The vacuum chamber 12 temporarily has a suction opening 12.2 connected to the suction device 11.

[0026] The device is positioned during operation such that the cooling cylinder 1 is held substantially coaxial with the spinning nozzle 14. For illustrative purposes, the spinning nozzle 14 is also shown here in dashed lines. A large quantity of monofilaments from the multiple nozzle openings of the spinning nozzle 14 are extruded through it. The vacuum source 11.1 of the suction device 11 generates a vacuum within the vacuum chamber 12 for cooling the newly extruded monofilaments, which propagates through the suction chamber 5, the permeable cylinder wall 2, and the filter element 3 into the interior of the cooling cylinder 1. This results in a suction effect, causing the monofilament outlet 9, which faces the environment, to become an air inlet. Cooling air is thus drawn from the environment, flowing as a reverse airflow from the monofilament outlet 9 to the monofilament inlet 6. Therefore, the cooling air flows in the opposite direction to the filament travel of the monofilament strip. Consequently, the sheath flow generated on the circumference of the monofilament during drawing can be advantageously abruptly opened by the reverse-directional cooling airflow to cool the monofilament strip. After the monofilament is cooled, the cooling airflow is discharged into the suction chamber 5 through the filter element 3 and the ventilated cylinder wall 2 of the cooling cylinder 1, and then passes through the vacuum chamber 12 from the suction chamber 5 to the suction port 10.

[0027] exist Figure 1.1 and Figure 2 In the exemplary embodiments of the apparatus according to the invention shown, only one cylinder within the suction chamber is illustrated. In principle, the suction chamber can accommodate multiple spaced-apart cooling cylinders to simultaneously cool multiple generated monofilament bundles. The cooling cylinders are preferably arranged in a single or multiple rows within the suction chamber. Air management is preferably performed using a vacuum chamber, such that the suction chamber is connected to the vacuum chamber across its entire cross-section.

Claims

1. An apparatus for cooling extruded monofilaments used in the production of filaments, the apparatus comprising a cooling cylinder (1) and a suction device (11) through which the monofilaments are guided, the suction device interacting with the cooling cylinder (1) in such a way that a reverse airflow is generated within the cooling cylinder, wherein the direction of the reverse airflow is opposite to the direction of travel of the monofilaments, characterized in that, The cooling cylinder (1) has a hollow cylindrical filter element (3) below the monofilament inlet (6), and the filter element (3) is attached to the outer ventilated cylinder wall (2). The cooling cylinder (1) is disposed inside the suction chamber (5), and the suction chamber (5) is connected to the suction device (11); The cooling cylinder (1) has a first annular seal (4) above the filter element (3) at the monofilament inlet (6), the first annular seal abutting against the chamber wall (5.1) of the suction chamber (5); and / or The cooling cylinder (1) has a second annular seal (7) at its lower end below the filter element (3), and the second annular seal (7) is attached to the chamber wall (5.2) of the suction chamber (5).

2. The apparatus according to claim 1, characterized in that, For replacement, the filter element (3) is loosely attached to the cylinder wall and configured to elastically deform through the monofilament inlet (6).

3. The apparatus according to claim 1 or 2, characterized in that, The filter element (3) is made of open-cell foam material or filter pad.

4. The apparatus according to claim 1 or 2, characterized in that, The cooling cylinder (1) is connected to a coaxially arranged pipe joint (8) at its lower end, and the pipe joint (8) forms a monofilament outlet (9).

5. The apparatus according to claim 1 or 2, characterized in that, The suction chamber (5) has a plurality of cooling cylinders (1) arranged at intervals from each other.

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