Spinneret

Abstract

A spinneret (1) for producing several filaments, comprising a plurality of perforations (2), each of which ends on the bottom side of the spinneret (1) into a respective outlet opening (3) for pressing a thermoplastic there through for forming the filaments, wherein the outlet openings (3) are arranged in rows (5) which extend along a cooling direction (A), from one side of the spinneret (1) to the opposite side, wherein these rows (5) are arranged increasingly close together, away from a line (C), along this cooling direction (A) and through the centre of the spinneret (1).

Claims

1. Spinneret for producing several filaments, comprising a plurality of perforations, each of which ends on a bottom side of the spinneret into a respective outlet opening for pressing a thermoplastic therethrough for forming the filaments, wherein the outlet openings are arranged in rows which extend along a cooling direction, from one side of the spinneret to the opposite side, wherein these rows are arranged increasingly close together, away from a line, along this cooling direction and through a center of the spinneret, wherein the outlet openings in each row of the spinneret are arranged increasingly far apart when viewed along the cooling direction for an entire length of the spinneret from the one side of the spinneret to the opposite side.

2. Spinneret according to claim 1, characterized in that a distance between successive rows is at most 5 times a diameter of each perforation.

3. Spinneret according to claim 2, characterized in that the distance between successive rows is at most 3 times the diameter of each perforation.

4. Spinneret according to claim 3, characterized in that the distance between successive rows is at most 2.5 times the diameter of each perforation.

5. Spinneret according to claim 2, characterized in that the distance between successive rows is at least 1.25 times the diameter of each perforation.

6. Spinneret according to claim 2, characterized in that the distance between successive rows is at least 1.5 times the diameter of each perforation.

7. Spinneret according to claim 1, characterized in that the outlet openings are arranged in circular arches, with more than two outlet openings per circular arch.

8. Spinneret according to claim 7, characterized in that the circles of the circular arches have a common tangential tangent.

9. Spinneret according to claim 8, characterized in that the tangential tangent is arranged behind the spinneret, viewed along the cooling direction.

10. Spinneret according to claim 8, characterized in that the tangential tangent extends at right angles to the cooling direction.

11. Spinneret according to claim 7, characterized in that the circular arches have an increasingly small diameter, viewed along the cooling direction.

12. Spinneret according to claim 1, characterized in that each outlet opening is three-lobed, wherein a lobe of this outlet opening is arranged counter to the cooling direction.

13. Spinneret according to claim 1, characterized in that the outlet openings in successive rows are arranged offset with respect to each other.

14. Spinneret according to claim 1, characterized in that this spinneret is circular.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be explained in more detail by means of the following detailed description of a preferred embodiment of a spinneret according to the present invention. The sole aim of this description is to give illustrative examples and to indicate further advantages and particulars of the invention and can thus not be interpreted as a limitation of the area of application of the invention or of the patent rights defined in the claims.

(2) In this detailed description, reference numerals are used to refer to the attached drawings, in which:

(3) FIG. 1 shows a spinneret according to the present invention in perspective from above;

(4) FIG. 2 shows the spinneret from FIG. 1 in cross section;

(5) FIG. 3 shows the spinneret from FIG. 1 in top view;

(6) FIG. 4 diagrammatically shows the rows and circles in which the outlet openings are arranged in a view of the spinneret from FIG. 1.

DETAILED DESCRIPTION

(7) The embodiment of a spinneret (1) according to the invention illustrated in the figures is circular and comprises 255 perforations (2). As can be seen in FIG. 2, each perforation (2) extends through the spinneret (1) from an access opening (4) on the top side of the spinneret (1) to an outlet opening (3) at the bottom side of the spinneret (1). The outlet openings (3) are arranged substantially inside a circle.

(8) In order to form filaments, a thermoplastic, such as polypropylene, polyester or polyamide, is pressed through these perforations (2) from the top side in order to leave the spinneret (1) on the bottom side as filaments. In order to cool these filaments, air is blown onto these filaments along the cooling direction (A), which is indicated in FIG. 4. Due to the positioning of the outlet openings (3), these filaments are cooled in an optimum manner.

(9) In FIG. 4, the outlet openings (3) are diagrammatically indicated on the spinneret (1) by means of crosses in order to illustrate their position on the spinneret (1).

(10) These outlet openings (3) are arranged in rows (5). The horizontal lines (5) in FIG. 4 indicate these rows (5) for half the spinneret (1) on one side of line (C) along the cooling direction (A) and through the centre of the spinneret (1). Thus, it can be seen more clearly that the further these lines (5) are situated from line (C) running through the centre of the spinneret (1), the closer together these lines (5) are arranged. The illustrated spinneret (1) is symmetrical with respect to line (C) running through the centre of the spinneret (1), so that the outlet openings (3) on the other half of the spinneret (1) are arranged in corresponding rows (5) (not shown).

(11) The diameter (d) of the perforations (2) of the illustrated spinneret (1) is 2 mm. The greatest distance between two successive rows (5) is 4.9 mm.

(12) Vertical lines (7) through the outlet openings (3) on the line (C) through the centre of the spinneret (1) furthermore illustrate in FIG. 4 that the outlet openings (3) of the illustrated spinneret (1) on each row (5) are arranged increasingly far apart, viewed in the cooling direction (A). The greatest distance between two such successive vertical lines (7) in the illustrated embodiment is 10.4 mm.

(13) In addition, it can be seen that the outlet openings (3) of the illustrated spinneret (1) are arranged on circular arches, the circles (6) of which are shown in FIG. 4. These circles (6) have a common tangential tangent (T) which is arranged behind the spinneret (1), viewed along the cooling direction (A), and extends at right angles to the cooling direction (A). These circles (6) have an increasingly small diameter, viewed along the cooling direction (A).

(14) In addition, due to the position of the outlet openings (3) in said rows (5) and on said circular arches, it is ensured that the outlet openings (3) in successive rows (5) are arranged offset with respect to each other.