Textiles: manufacturing – Thread finishing – Surface modification of running length
Reexamination Certificate
2001-01-03
2001-10-30
Worrell, Danny (Department: 3765)
Textiles: manufacturing
Thread finishing
Surface modification of running length
C028S247000
Reexamination Certificate
active
06308388
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The invention relates to a texturing jet for treating a filamentary material in a treatment duct formed between at least two superimposed body members, including at least one jet body for feeding a gaseous treatment medium and at least one vent portion provided in the treatment duct.
Multifilaments are threads made of synthetic polymers such as, for instance, polypropylene, polyamide, polyester or the like, which are applied in the most diverse fields. Apparatus for the production of multifilament threads comprise an extruder in which the starting material in granulate form is melted and pressed through a spinneret. Depending on the number of filaments desired per thread, the spinneret comprises the respective number of holes through which the synthetic material is pressed. Besides round cross sections, the holes of the spinneret may also have other cross sectional shapes in order to impart special properties on the filaments. The extrusion procedure is followed by a cooling process, after which the filaments are united to a thread. Depending on the purpose of use of the thread, various drawing processes, texturing processes and cooling processes follow, where-upon the yarn is finally wound on appropriate bobbins. Texturing serves to impart specific properties on the synthetic fibers or woven fabrics or the like resulting therefrom. If the yarns are used for carpets, the synthetic fibers are, for instance, treated with hot compressed air so as to cause appropriate crimping of the yarn, yet without individual filaments being allowed to break or tear. Those processes are known in the art as BCF texturing (BCF=bulked continuous filaments). The present invention is related essentially to such BCF texturing. In that process, crimps are introduced into the drawn yarn by hot air texturing. The texturing jets are operated in a range of from 145 to 150° C. and at a pressure of 7 to 8 bars.
A texturing jet of the initially defined kind is described, for instance, in U.S. Pat. No. 4,949,441 A and the corresponding EP 495 886 B1. There, a filament yarn is sucked in through an injector and pulled downwards by the aid of hot air which is deflected accordingly. After this, the thread at a high speed and plastification temperature impinges on a tangle yarn plug within a chamber provided with a plurality of slots, thus being nonuniformly bent a great number of times, i.e., crimped. After texturing, the yarn is conducted over suitable cooling drums for cooling and, usually in a further step, is subsequently intermingled, which means that knobs are introduced so as to cause the filaments to be fixed within the yarn before the yarn is wound on appropriate bobbins. The texturing jet is comprised of a body member, a cover plate and an internal plate sandwiched therebetween and formed by a stack of laminae, one of which forms an elongate duct whose cross section changes both in breadth and in height between inlet and outlet. The body member is provided with two spaced-apart bores through which a fluid is fed for treating a strand material which is conducted through the duct. The stack-shaped laminate of the internal plate offers the advantage that only the duct-forming lamina will have to be replaced in the event of worn duct walls. However, the price paid for this advantage is the disadvantage that the construction of an internal plate including stacked laminae is highly demanding in respect to both production and mounting.
DE 30 19 302 A1 discloses a jet for intermingling yarns, which comprises a closed yarn travelling duct of rectangular cross section and gas feed ducts, wherein the duct widens stepwisely on one broadside or on both broadsides, the enlargements of the yarn travelling duct again narrowing to the original cross section.
U.S. Pat. No. 3,638,291 A describes a texturing jet in which the duct-forming body is comprised of but two parts whose oppositely arranged surfaces are plane, wherein the yarn travelling duct, which has a constant depth and includes lateral recesses, is formed in the surface of one of the bodies.
DE 38 29 150 A1 describes an air jet for pneumatic false twist spinning, which is comprised of several sections. The section that is arranged downstream of the section including the compressed air ducts is made of a harder, more wear-resistant material such as, e.g., ceramics.
DE 39 27 910 A1 describes a false twist spinneret provided for pneumatic false twist spinning, in which at least part of the inner wall of the blowing duct is provided with a coating or an insert made, for instance, of a ceramic material, in order to reduce the cross section of the exit opening.
The two last-mentioned documents describe spinning processes for staple fibers in which the yarn is not crimped or bulked, but stretched and formed into a lower-strength yarn within the air jet. The technology described in those documents, therefore, differs substantially from the technology underlying the present invention. Moreover, replacement of the inserts involves relatively high expenses.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a texturing jet which stands out for its easy production, problem-free mounting and simple maintenance. It is to be feasible to readily and quickly exchange, in particular, the more sensitive and more rapidly worn components of the texturing jet. The texturing jet according to the invention is to enable the fabrication of yarns exhibiting characteristics as good as possible and also as symmetrical as possible. The adaptation of the texturing jet to different yarn qualities is to be feasible as quickly and simply as possible without having to exchange the entire texturing jet.
This object is achieved in that the treatment duct at least in partial regions is realized with a material that is more resistant than that of the body member.
Advantageously, the more resistant material is comprised of a ceramic material. Apart from its poorer workability, a ceramic material offers a great number of advantages.
According to another characteristic feature of the invention, the more resistant material is provided by an insert inserted in the body member. This enables worn components to be exchanged readily and quickly without having to replace the entire texturing jet. On the other hand, the texturing jet may be readily adapted to varying conditions such as, varying yarn characteristics, by replacing such inserts.
Alternatively, the more resistant material also may be provided by an attachment attached to the body member.
Advantageously, the jet body of the texturing jet is contained in the insert or in the attachment, respectively. It is exactly the jet body which constitutes a texturing jet component that is particularly prone to wear. Moreover, the yarn properties are decisively influenced by the jet body.
If the insert is resiliently mounted in the body member, the optimum closure will be reached as the body members constituting the texturing jet are being assembled.
Said resilience may be provided by indents realized in the insert.
In order to obtain as uniform a plug formation as possible and hence also uniform crimps as well as yarn properties, it is provided according to a further characteristic feature of the invention that the treatment duct has a square cross section in the vent portion with aeration windows formed by perforated plates or the like being provided on each side of the treatment duct. Due to the symmetrical configuration of the vent portion, a texturing air flow-off as symmetrical as possible and hence uniform yarn properties will be achieved. In addition, any undesired propagation of the twist will be effectively prevented.
If the perforated plates or the like are fastened to the body member by means of magnets, the latter may be exchanged in an accordingly simple and quick manner.
If, as in accordance with a further characteristic feature of the invention, a die part is connected to the runout of the treatment duct, or integrated in the texturing jet, for directly supplying to a cooling drum
Samuels Gauthier & Stevens
SML Maschinengesellschaft m.b.H.
Worrell Danny
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