This Patent Application claims priority to German Patent Application No. 10 2008 029 550.7 filed on Jun. 21, 2008, entitled, “DEVICE FOR DRAWING FILAMENTS”, the contents and teachings of which are hereby incorporated by reference in their entirety.
The invention relates to a device for drawing a plurality of filaments.
A conventional device for the production of a spunbonded fabric is known from US publication 2006/0172024. In order to produce a spunbonded fabric, a fusible polymer fed by an extruder is spun into a plurality of filaments by nozzle bores that are arranged in a linear manner, in single or multiple rows in a spinning beam, and subsequently cooled by a cooling device. A tensile force is exerted onto the filaments by a device for drawing that is arranged at a distance beneath, that is to say a drawing nozzle in the form of a slot, which tensile force causes the stretching and conveying of the filaments. For this purpose compressed air flows from the interior wall of the drawing nozzle into the conveying direction of the filaments, by way of which the desired tensile force is exerted onto the filaments. The filaments are deposited on a conveyor belt arranged beneath the drawing nozzle in a randomly oriented position, and form the fabric at that location.
In order to influence the airflow and the filaments during the discharge from the drawing nozzle, such that the deposit of the filaments is carried out as uniformly as possible, a finger strip having a pinnacle-shaped cross-section is provided. The finger strip is provided on the discharge side of the drawing nozzle, which extends across the width of the drawing nozzle.
Despite prior art measures, there is still a risk that thin spots and the formation of filament bundles may occur in the spunbonded fabric due to an uneven deposit of the filaments in the spunbonded fabric.
The present invention provides an improved drawing nozzle in order to ensure a uniform thread deposit. Furthermore, the invention provides for flexible adjustability of the drawing nozzle to different process parameters such that an optimum adjustment can be achieved more readily.
For this purpose the drawing nozzle has a guide member on the base thereof, which extends across the length of the slot on the outlet side. The guide member is equipped with a plurality of bores, which connect the outlet region with the environment, thus enabling a passive exchange of air. In this manner the sudden expansion of the conveyor air into the environment is attenuated, since the pressure ratios directly at the outlet of the drawing nozzle can be adjusted to the pressure ratios of the environment more uniformly.
Surprisingly it has been shown that especially by using the combination of a guide member having notches in the conveying direction on the outlet side of the drawing nozzle on the one side of the slot, and a guide member having bores on the other side, particular advantages are achieved as compared to only one guide member.
In an alternative embodiment guide members are provided with bores on both sides of the slot.
In a particularly advantageous further improvement of the invention one of the guide members, or both guide members can be adjusted toward the conveyor direction with regard to the angle thereof. In this manner the effect of the guide member can be adjusted in a particularly fine manner, thus optimally adjusting the same to the process.
One preferred embodiment variation of the invention includes multiple rows of holes, in which the bores are inserted.
In a preferred further improvement, part of the bores is arranged above, and another part of the bores is arranged beneath the lower edge of the opposite guide members. A particularly uniform exchange of air with the environment can be achieved in this manner.
A soft flowing in of air is achieved by way of expanding the bores toward the interior of both guide members.
The soft flowing in of air is also achieved by way of interior notches, which extend from the bores in conveyor direction.
A uniform flow is also obtained if interior notches are provided beneath the bores without any connection to the bores.
In an embodiment variation, the bores are embodied in an angular manner, transverse to the conveying direction, at an angle of about 10 to 60°. The lateral speed component of the inflowing air executes an angular momentum onto the filaments, which aids in the formation of the randomly oriented positioning.
Another embodiment variation provides bores that are angularly arranged in the conveyor direction, which are provided in or opposite to the conveyor direction, at an angle of between about 10 to 60°. An inflow or outflow of air can be supported in this manner.
Even if according to the invention each angle of greater than 0° is included, the lower threshold of 10° is selected in order to thus obtain a transverse component. In manufacturing, any angles above 60° can be created only at great expense.
Optimum results are obtained using the device according to the invention, if the bore diameter is within a range of about 0.5 to 10 mm.
One example embodiment is described in further detail below, based on the attached drawings in which:
The drawing nozzle 6 is located beneath the spinning unit 3, which also extends perpendicular to the drawing plane across the width of the filament bundle 5. A cooling device may be located above the drawing nozzle 6.
It is a function of the drawing nozzle 6 to exert a tensile force onto the filament bundle 5 and to convey the same. For this purpose the filament bundle 5 is guided through a funnel-shaped intake region 7 in the drawing region 8. A compressed air feed 9 is provided on both sides in the drawing region 8, via which the compressed air is fed, which is guided into the drawing region at an acute angle, and which exerts a tensile force onto the filament bundle at that location. The drawing region 8 forms a slot 10, which extends perpendicular to the drawing plane.
A conveyor belt 19 is provided beneath the drawing nozzle 6, on which the filament bundle discharged into a fabric 18 is transported.
The guide members 13 and 15 are attached directly beneath and in connection with the drawing nozzle 6 by receptacles 11 and 12. The optional receptacles 11 and 12 enable the quick and flexible installation of the guide members 13 and 15. In this manner the guide members 13 and 15 may be easily exchanged for other guide members having a deviating geometry, and adjusted to modified process parameters. The guide members 13 and 15 are positioned such that the slot 10 is continued beneath the drawing region.
The guide member 13 has a plurality of notches 14 perpendicular to the drawing plane, which extend in the conveying direction of the drawing nozzle, wherein the notch depth increases in the conveying direction. In this manner a more uniform airflow is achieved from the drawing nozzle 6 such that the filaments are distributed more evenly on the conveyor belt 19, thus creating a more uniform fabric 18. In addition to the guide member 13, another guide member 15 is provided in the form of a thin-walled strip, having a plurality of bores 16. For this purpose the bores 16 connect the space beneath the drawing region 7 of the drawing nozzle 6 with the environment, thus enabling an exchange of air with the environment. An aerodynamic, particularly uniform transition from the drawing region 7 into the environment is achieved in this manner. Due to the double-row arrangement of the rows of holes 16 (not illustrated), where the lower row of holes is arranged beneath the lower edge 20 of the guide member 13, the exchange of air may occur in a particularly uniform manner.
As an alternative to the arrangement illustrated, 2 guide member 15 including bores 16 may also be arranged on both sides of the slot 10.
The two guide members 13 and 15 are again illustrated in
Threaded bores 28 in the guide member 15, and in the guide member 14 (not illustrated), enable the simple installation of the guide member.
Even though the alternative embodiments in
While various embodiments of the invention have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
1 melt source
2 melt line
3 spinning unit
4 spinning nozzles
5 filament bundle
6 drawing nozzle
7 intake region
8 drawing region
9 compressed air feed
10 slot
11 receptacle
12 receptacle
13 guide member
14 notch
15 guide member
16 bore
17 screwed connection
18 fabric
19 conveyor belt
20 lower edge of guide member
21 jointed receptacle
22 joint
23 outlet opening
24 notch
25 notch
26 orthogonal of the guide member
27 bar
28 threaded bore
α setting angle
β inflow angle
γ outflow angle
Number | Date | Country | Kind |
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10 2008 029 550 | Jun 2008 | DE | national |
Number | Name | Date | Kind |
---|---|---|---|
3766606 | Piper et al. | Oct 1973 | A |
6379136 | Najour et al. | Apr 2002 | B1 |
6974316 | Maggio | Dec 2005 | B2 |
6979186 | Schmit et al. | Dec 2005 | B2 |
20060172024 | Bentley et al. | Aug 2006 | A1 |
Number | Date | Country | |
---|---|---|---|
20090317505 A1 | Dec 2009 | US |