FI71358B - OVER ANCHORING FOR SAMMANBLANDAND AV FILAMENT AV ETT MULTIFILAMENTGARN - Google Patents

Description

1 71358

A method and apparatus for mixing fibers of a multifilament yarn

The invention relates to a method for mixing the fibers of at least one multifilament yarn in the following steps: passing at least one yarn through a gas jet in a fiber mixing zone, the zone having a closed yarn channel with a yarn inlet end and a yarn outlet end, preferably between the ends lie-10, preventing lateral vibrations of the fibers upstream of the mixing zone, at least one rapid jet of compressible gas strikes at least one wire in the duct to vibrate and mix the fibers, and the wire is withdrawn from the mixing zone and the apparatus to perform the method.

Gas jet mixing machines have long been used to produce untwisted, uniform yarns and, in addition, to combine several yarns into a single, uniform yarn in which the fibers of different yarns are mixed together. See. e.g., U.S. Patent 3,364,537 to Bunting and Nelson. In these yarns, the fibers can be mixed together more or less depending on the quality of the different yarns, the structure of the device, and the severity of the mixing conditions. Thus, the methods are suitable for various applications for combining smaller yarns into a larger yarn, i. doubling, to combine yarns of different colors or to be dyed differently to produce different, multi-colored yarns, such as marker and tweed yarns, with textured or non-textured yarns.

U.S. Patent 4,069,565 (Negishi) relates to an apparatus and method for making a textured multifilament yarn having closed portions and open portions alternately in its longitudinal direction. In the method, the running fiber bundle 35 is brought into contact with two curved pieces ___ - -! Γ 2 71358 spaced longitudinally apart, whereby the wire line is folded at each point of contact. The fluid transit of fibers is formed under tension in the entire space between the two pieces.

5 At least one gas stream is then discharged against the bundle in this channel from the other side of the bundle, so that the different fibers of the bundle begin to oscillate and run randomly and intermittently in the direction of the discharged gas stream. For operation to be effective, the wire line must be folded at each point of contact on both the upstream and downstream sides of the mixing zone. According to the patent, the position of the gas flow between the contact points is also critical and should preferably be at their midpoint.

U.S. Patent 4,059,873 discloses a method of making a textured, continuous long fiber tweed yarn by introducing a plurality of threaded long fiber yarns of varying colors and / or color acceptability and having the fibers separated to substantially remove yarn uniformity to a mixing zone. . The gas stream mixes the fibers with each other and further takes the formed wire forward from the mixing zone. The yarn is shown folded substantially rectangular with respect to the yarn passage-25 road mixing zone at both the entry and exit points.

The objects of the invention are e.g. an improved method (and apparatus) for making a unitary yarn, mainly a textured yarn, by means of a gas jet device and in which there is no need to fold the yarn path at the inlet-30 or exit of the mixing zone. In addition, the aim is a more energy-efficient method for joining yarns, especially for producing a textured, Tweed-type dyed carpet yarn, and an economical method that operates at high yarn speeds.

The method according to the invention is characterized in that the wire is introduced into the mixing zone along a path substantially coaxial with the wire channel, the lateral oscillations of the fibers in the wire being limited peripherally by a tubular stopper extending at least 7 cm upstream, and the wire is pulled out of the mixing zone along a path that is substantially coaxial with the wire channel.

The invention is particularly efficient and economical when a single jet of compressed gas with a cross-sectional area smaller than the wire channel is struck perpendicularly in the channel to the wire or wires, especially at a wire speed of at least 1371 m / min.

The method is particularly efficient and useful for combining a plurality of non-uniform or less uniform yarns into a single, more uniform yarn with a higher denier, i. the twisting. In a preferred embodiment of such a method, textured yarns are combined which can be dyed in various ways to obtain multicolored yarns, such as brand or tweed type yarns, at almost any degree from very thick to very fine. In order to obtain textured tweedlan yarns with a high degree of mixing, it is preferred that the coefficient of coherence or uniformity of the yarns entering the mixing zone be less than 6.0. A higher coefficient of uniformity of the input yarns results in less mixing and a more blatant color mixing effect.

To facilitate mixing of the fibers, the yarn is preferably removed from the zone at a rate 2 to 15% lower than the rate at which it is fed into the zone, preferably 5 to 15% when the textured yarns are fed directly from the zone where the input yarns or yarn fibers are cleared. Under certain conditions, it is also possible to improve the performance and appearance of the wire by also limiting peripheral lateral vibrations in the treated wire as it is removed from the mixing zone (i.e. by a pipe stop on the downstream side of the zone in a manner comparable to the upstream 5 pipe stop). An additional limiter can be used, e.g., for input yarns that are dyed and thus contain less than about 0.3% by weight of yarn finishing agent.

The present invention further provides an apparatus for mixing the fibers of at least one multifilament yarn and comprising a gas jet body portion mixing the fibers, a yarn channel which is preferably cylindrical and extends through the body portion and has a yarn inlet end and an outlet end, at least a single gas line passing through the duct-15 but the body, the axis of which intersects the longitudinal axis of the duct, a device for supplying compressed gas under high pressure to the duct, a device for delivering the wire or wires at a controlled speed to the duct inlet, a device for removing the mixed wire from the output end, a wire guide 20 between the wire feeder and the wire end of the wire and forming a wire straight path between the guide and the wire inlet end, which track is coaxial with the channel.

The device according to the invention is characterized in that the guide consists essentially of a tube with a longitudinal bore oriented substantially coaxially with the channel and arranged along a straight path between the wire feeder and the wire inlet end and having an outlet adjacent to the duct inlet sufficient to substantially prevent jet-induced lateral vibrations of the fibers in the wire on the upstream side of the bore outlet.

The bore length is preferably at least 12.7 cm and more preferably at least 25.4 cm according to the method described above. Normally, the ratio of channel to bore diameters should be at least about 1.3: 1.0, preferably at most about 4.0: 1.0. The device is particularly effective when the outlet end of the upstream pipe is at a distance of about 0.3175 to 1.27 cm from the inlet end of the duct.

5 For textured yarns with a conventional carpet denier, i.e. 1000 to 15000 denier, the effective diameters of the tube bore are about 1.52 to 6.35 mm.

The device may include a guide tube of corresponding dimensions located at a clearance between the outlet end of the wire channel and the discharge means coaxially along the wire path.

Putting water on the wire before the mixing step improves the operation of the method and the mixing efficiency. Humidification devices are known in the art for this purpose. Water 15 should be used in an amount of about 5-25% by weight of the yarn, but the amount is not critical.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a schematic vertical sectional view of a device 20 according to the invention with a tubular wire guide A 25-wire yarn guide only upstream of the sugar machine and preceded by a tightening zone and brake pads to remove fiber clutter from the feed yarns.

According to FIG. from the roller 18 and the associated chamfered roller 20. The upstream pipe guide 30 and any downstream pipe guide 36 (drillings of these are shown) are coaxially oriented by respective supports 32 and 38 6 71358 and the jet body portion 34 has a cylindrical wire channel 33. The body portion 34 is shown in cross-section to show a passage 33 intersected by a gas line 35 smaller than the perpendicular. The gas line 35 is supplied with a compressible kaa-5 su under pressure from a source (not shown). The distance between the pipe guides 30 and 36 determines the length of the mixing zone caused by the action of the gas jet device. The device for removing the mixed yarn from the mixing zone consists of an outlet guide roll 40. Behind the roll 40 is a conical roll-10a (not shown) or other suitable roll and winding device. The roll 40 is held in place by a support 42 to form a straight wire path from the roll 18 to the roll 40 coaxially with the tubes 30, 36 and the channel 33.

As shown in Figure 1, differently dyed, text-15-threaded, multifilament inlet yarns 50, 52, 54 from different packages attached to a perimeter (not shown) are pulled by rollers 18, 20 through a guide 12 and a humidifier 14 around a roll 16. and then passed in a converged, adjacent relationship to the upstream end 20 of the tube 30, through the body portion 34 and the tube guide 36. They are removed by means of a removal roller 40 in the form of a mixed Tweed-type dyed uniform textured yarn 58.

The device shown in Fig. 2 is the same as in Fig. 1, 25 except that the downstream tubular guide 36 is omitted and a drawn tension roller 24 and an oblique roller 22 connected thereto are added, as well as parallel brake rods 28 mounted on the base 26 for the input wire fibers. to determine before 30 mixing.

The tubular guides stabilize the wire, which apparently enhances the mixing performed by the jet in the mixing zone. In addition, this reduces the formation of individual fiber loops caused by the cluttering effect of locking the 7,71358 fibers "out of place". If desired, the end of the wire channel can be slightly limited, e.g., by an eccentric wire curler, as shown in U.S. Patent 4,059,873 (Nelson) in Figure 2, or by a concentric restrictor, such as a smaller diameter hole in a metal plate to be inserted. against the inlet end of the wire channel; but such a limiter tends to reduce the efficiency of the mixing zone, resulting in less confusion at the intersection areas. When the confusion is more than sufficient, such a restrictor can be used to provide a small jet feed effect on the yarn as it exits the mixing zone, or to provide a more uniform, less knotted structure along the yarn.

The input yarns used in this invention may be solid folded textured. The textured inlet yarns are preferably those textured by a hot gas jet, e.g., in accordance with U.S. Patent 3,781,949 (Breen et al.). These yarns have better texting and normally some uniformity due to the mixing of the fibers, but this mixing usually occurs only partially between the fibers anywhere along the yarn and rarely between all the fibers at a given location. So when two or more wires are connected po. in the invention, without first eliminating this mixing, the fiber bundles open to a limited extent so that the fibers of the different yarns can mix to some extent, but if the resulting yarn is then cross-dyed, the yarn is usually a strong mixture of different yarn colors and color mixing. When this uniformity is removed by tightening and braking the input yarns prior to blending, the fibers of the yarns can open and blend together more freely and more frequently, resulting in more areas of blended colors.

35 As used herein, "textured" means yarns of which 8 71358 sa are permanently curled fibers, i. where the fibers retain their curl when removed from the yarn. By "differently dyed" is meant yarns which can be cross-dyed in a common color bath into different colors or shades. The word also covers yarns of different colors, because even after dyeing with a common color, these yarns remain "dyed" in different ways, i.e. different colors.

The yarn-to-fiber uniformity coefficient test used herein is determined in a known manner by fixing a yarn sample vertically with a tension produced by a weight in grams of 0.20 times the denier of the yarn, but not more than 100 grams. A hook with a weight, the total weight of which in grams is 15 to the average of the yarn per center fiber, but which weighs not more than 10 grams, is inserted through the bundle of yarn and lowered at a speed of 1 to 2 cm / sec until the yarn carries the weight of the hook. whose hook has traveled along the yarn until the yarn carries the weight, 20 is characterized by the amount of mixing of the fibers in the yarn. The result is expressed as the "uniformity factor", defined as the number 100 divided by the distance traveled in cm. Because the mixing of the fibers is random, the test is performed on a sufficient number of samples to obtain a representative average for the test yarn.

For more blended yarns with a larger denier, such as po. in the case of the carpet yarns made by the invention, a lateral tensile test gives a more accurate measure of the integrity of the yarn. In this known experiment, two hooks are placed at an randomly selected location approximately at the center of the sample yarn to divide it into two groups of fibers. The hooks are pulled apart at a speed of 12.7 cm / min and at a 90 ° angle to the wire axis by a tensile testing machine that measures the separation resistance of 35 hooks, e.g., an "Instron" machine.

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The wire is pulled with the hooks / until a force of 454 g is applied, at which point the machine is stopped and the distance between the two hooks is measured and recorded. Ten measurements are made for each wire and the average is the pull-out value.

5 The length of the test wire sample should be at least 10 to 15 cm and the wire should be randomly selected from the entire wire pack to be tested.

Example 1 This example demonstrates the importance of tube guides in the apparatus and method of the invention when using textured inlet yarns in which the fibers are already reasonably blended (moderate yarn integrity), such as textured, continuous fiber nylon yarns used commercially as straight manhole yarns. The uniformity factor of these lan-15s is generally about 25-50. The apparatus and method are in accordance with Figure 1.

The jet body has a wire duct with a length of 2.54 cm to 0.002 cm and a constant diameter of 0.58 cm "t * - Q, 0Q2 cm and is cut perpendicularly at its center by a cylindrical gas line with a diameter of 0.32 cm - 0.002 cm The center line of the cable intersects the center line of the channel within 0.00254 cm The edges of the inlet and outlet ends of the channel wire are rounded to a radius of 0.76 mm The shower unit is made of stainless steel block, type 416, width 25 3.81 cm, height 2.54 cm and a depth of 2.86 cm The channel extends through the block from the perpendicular top end to the lower end centered between each end, has a centerline 1.27 cm from the front of the block and a cable extending in from the back of the block. Air is supplied to the line at a pressure of 10.5 kg / cm, which flows through it at a rate of 1.02 mVmin at ambient temperature.

The feed rollers 18,20 feed the yarns at a speed of 914 m / min. The yarns make at least 8 turns of yarn around the rolls 35 to ensure a constant feed rate. Water is added to the yarns with a humidifier 14 at a rate of 3.79 l / h. The speed of the conical take-up reel is adjusted to provide a 3% overfeed from the feed rollers.

A piece of commercial, seamless, stainless steel tube with a bore diameter of 2.13 mm and a length of 5 27.9 cm, which limits the peripheral lateral oscillations in the wire upstream of the shower, is directed coaxially with the wire channel and is located so that its there is a clearance of .64 cm between the outlet end and the inlet end of the wire duct. The inlet end of the tube is about 13.97 cm from the point where the inlet wires exit the surface of the feed roller on their way to the spray device.

This equipment is used with three input wires as follows for each of the following products: (A) Each input wire denier is 1225. These are commercial (DuPont) textured, continuous fiber nylon yarns treated by the hot gas jet network texturing method. The yarns can be dyed in different ways - one is cationically dyed (type 854), one is light acid dyed (type 855) and one is deep acid dyed (type 20 857). The yarns have a standard spinning finish of 0.7% average finish in the yarn and the packaging limits are in the range of 0.4-1.35% finish in the yarn.

The three yarns are made into a single yarn under the above conditions. Mesh-25 inspection of the cross-shaded skeins reveals a periodic knot structure and a significant amount of fiber mixing (despite the mixing already present in each input yarn). The yarn gives a pull-out value of about 3.18 cm.

The second wire is made of the same three inlet wires 30 under the same conditions, but with the addition of a pipe guide having the same dimensions as the one coaxially directed upstream of the jet with the wire duct, with a gap of 0.64 cm between the outlet end and the downstream guide pipe inlet. Visual inspection of the cross-dyed coils of yarn 35 and the pull-out uniformity values shows that the yarn is substantially the same as

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713 5 8 for manufacture without downstream pipe.

B) Using the same conditions as in (A), the three ends of the space-dyed 1820T-497 textured, continuous-fiber nylon yarn are kneaded together to form a uniform yarn. The yarns are randomly dyed, which means that the appearance of the wound storage packages is beige / brown. Due to the dyeing, the yarn's own spinning finish has been reduced by about 0.25% by weight. A yarn made using both an upstream and a downstream tube guide, as above, 10 has a desirable periodic braid structure along the yarn, resulting in a pull-out value of 4.06 cm. Under the same conditions, except that no water was added to the yarn, only slight mixing is achieved, so that a meaningful separation test cannot be performed. The third test is performed using only the upstream pipe guide and adding water. The resulting yarn has a less desirable knot braid structure at random intervals along the yarn and has a mean pull-off of 5.84 cm. From this, it is concluded that in order to confuse the input wires with a low finish of 0.3%, the best results are obtained by adding water and using pipe guides both upstream and downstream of the jet.

Example 2 This example shows the efficiency of tube guides on the same inlet wires and under the same conditions as in Example IA, except that reasonable uniformity in the inlet wires (i.e. 25-50) is first removed from each wire to obtain a uniformity factor of less than 6.0. This is achieved by separating the fibers under tension using a set of parallel brake rods and the apparatus of Figure 2. In this case, four brake sticks with a diameter of 6.35 mm are used. Their center point is about 1.27 cm. The speed of the tension rollers 24.22 is adjusted to obtain a tension in the yarns between them and the feed rollers, which is about 1.2 gpd. Using these 35 input wires with low uniformity, the overfeed i2 71 358 can be increased to 10% between the feed rollers and the discharge roller.

The cross-dyed coils of the yarn thus made have a desirably regular, intermittent braided knot structure with portions in between where the fibers are effectively mixed.

5 The pull-out test gives a value of 2.29 cm.

This method is repeated under the same conditions, except that no water is added to the yarn with a humidifier. The product is again a well-mixed, well-tangled yarn with a pull-off value of 2.54 cm, but the intermittent, well-tangled areas are less dense than above. So under these conditions, there is no need to add water to get a good product.

The procedure is repeated (using water), except that the speed of the inlet wire is increased to 1,828 m / min and the overfeed to 12%. The cross-dyed coils of the yarn made in this way have a clear difference in the tangled structure compared to that made at a lower speed. The intermittent knot-braid structure of the slower yarn is replaced by a randomly mixed fiber bundle structure with a more uniform density along the yarn. The degree of mixing of the fibers is quite good considering the high speed of the yarn and the relatively low air flow in the jet (1.02 m / min) .1 It is concluded from these experiments that ordinary, commercial, textured, continuous fiber feed-25 gat, which contain normal amounts of spinning finishing (i.e., at least about 0.75%) only need an upstream control tube for efficient operation.

Similar results were obtained in a series of experiments using guide tubes with bore diameters of 1.52 mm, 3.05 mm and 3.86 mm and lengths of 15.24 cm and 27.94 cm.

The differences in color mixing and entanglement are small throughout the series. For each pipe size, a clearance of 6.35 mm is maintained between the end of the guide tube and the inlet end of the wire channel. Otherwise, the conditions were considered essentially the same.

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Example 3 This example essentially repeats the first operation of Example 2 under the following conditions. The input wires are the same and the device is again as shown in Figure 2. The speed of the feed roller 5 is 1023 m / min. The input wires are separated until the uniformity factor is less than 6.0, with a tension of 1.14 gpd.

One guide tube is used from the shower on the upstream side and has a length of 27.94 cm and a bore diameter of 3.86 mm.

Its end on the downstream side is 6.35 mm from the inlet end of the wire channel 10. The shower is of the same design as in Example 2, except that the diameter of the gas line is 3.96 mm. Air is supplied to the gas line at a pressure of 75 PSI (5.27 kp / cm) and a temperature of 25 ° C, resulting in a flow rate of 0.64 m3 / min. The 3-slot humidifier is operated at a flow rate of 3.79 l / h. The conical roller adjusts the discharge speed to 920 m / min, giving an 11% overfeed. The uniform yarn product is wound into a package with a winding tension of 225 g. Under these conditions, the production capacity is 25.4 kg per point per hour.

Although a lower barometric pressure is used herein than in Example 2, a yarn woven from the dyed fabric is more blended than the reference yarn made under the same conditions, but at a much higher barometric pressure and flow using the method and apparatus of U.S. Patent 4,059,873.

25 Example 4 This example shows the effect of the length of the guide tube on the efficiency of the operation and the appearance of the wire under the conditions of Example 3. Here the operations are similar, except that tubes with lengths of 3Q 2.54 cm, 7.62 cm, 12.7 cm and 27.94 cm and a textile yarn guide with a length of 0.64 cm are tested and there is no guide at all. between the feed rollers and the wire channel. The operation is most efficient with a pipe with a length of 27.94 cm. The wires entering the shorter silicon tubes have an unstable vibration action, which is particularly evident with tubes with a length of 7.62 cm and the like. 12.7 cm.

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The appearance of cross-dyed coils of yarn is appreciated. The length of the tube must be at least 7.62 cm to obtain a flat, well-mixed yarn. If the tubes are shorter or there is no tube at all, there is less mixing and the knots are less evenly distributed in the yarns. The preferred length of the tube for operational efficiency and wire appearance is therefore at least 12.7 cm.

Example 5 This example illustrates the use of the invention in the manufacture of a very high denier yarn for carpets.

The device is as shown in Figure 2 and uses brake sticks to clear the input wires to obtain a uniformity factor of less than 6.0. Three types of commercial hot-jet gas-jet-textured, continuous-fiber 66-nylon yarn are combined into one yarn using the two ends of each yarn type (six yarns in total). The yarn types are cationic 1225 denier (type 494) medium matt yarn, 1225 denier light acid dyed (type 495) kes-2Q matt yarn, and 2470 denier deep acid dyed (type 487A) medium matt yarn. The jet body structure is similar to the previous examples except that the duct diameter is 0.79 cm and the air duct diameter is 0.54 cm. Air is supplied to the line 2 at a pressure of 7 kg / cm and a flow rate of 1.12 m 2 / min. The feed rate is 416 m / min and water is added at a flow rate of 7.57 l / h. The only upstream guide tube is 27.94 cm long and has a bore diameter of 0.39 cm. Its outlet end is 0.64 cm from the inlet end of the duct. The taper roller adjusts the thread removal speed to 377 m / min to obtain a 10% 30 feed. The resulting yarn has a total denier of 10,400 and has a periodic knot braid structure in which the fibers are mixed considerably with each other among the sub-yarns. The cross-dyed carpet made of yarn has a Tweed-type appearance without specified directions and a deep-35 dyed sub-yarn predominates.

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Example 6 This example illustrates the use of the invention in threading solid (non-textured) yarns to make a unitary, solid yarn with a thicker denier.

5 The input yarns consist of three ends of a drawn, 1000 denier 68-fiber, zero-thread, flat 66-nylon yarn that is not braided and is substantially free of entangled fibers. The yarn contains 0.8% standard finish. The device is the same as in Example 3, except that the tension rollers and brake rods are not used because the input wires are substantially free of entangled fibers.

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The compressed gas is air with a pressure of 7 kg / cm and a flow rate of 0.84 m / min. A winding tension of 200 g is used and the denier of the yarns obtained is about 3100. The two different overfeeds 15 are used, each with and without one pipe guide preceding the mixing zone. The conditions of the method are otherwise the same as in Example 3. The results are as follows:

With pipe Without pipe 20% overfeed 2.1 7.6 2.1 7.2 pull-out, cm 3.56 3.12 5.92 7.16

It is apparent that based on these results, the tube guide significantly improves the efficiency of the mixing of the fibers performed by the mixing zone.

Claims (12)

71 358 A method of mixing the fibers of at least one multifilament yarn in the following steps: 5 passing at least one yarn (50, 52, 54) through a gas jet in the fiber mixing zone, the zone having a closed yarn channel (33) having a yarn inlet end and a yarn outlet end and which is preferably cylindrical between the ends, prevents lateral vibrations of the fibers upstream of the mixing belt zone 10, at least one rapid jet of compressible gas strikes at least one wire in the channel (33) to vibrate and mix the fibers and pulls the wire out of the mixing zone. 52, 54) is introduced into the mixing zone along a path substantially coaxial with the wire channel (33), lateral oscillations of the fibers in the wire are limited peripherally by a tubular stop (30) extending from the starting point of the mixing zone 20 adjacent the inlet end of the wire channel (33) along a wire line of at least 7, 62 cm upstream, and the wire is pulled out of the mixing zone along a path substantially coaxial with the wire channel (33). A method according to claim 1, characterized in that the yarns (50, 52, 54) to be dyed differently have a coherence factor of less than 6.0 when introduced into the channel (33). Method according to Claim 1, characterized in that the wires (50, 52, 54) are fed into the duct 30 at a speed of at least 1371 m / min. Method according to Claims 1 to 3, characterized in that the cohesive yarn is removed from the mixing zone at a rate which is 2 to 15% less than the rate at which it is fed into the zone. An apparatus for mixing the fibers of at least one multifilament yarn (50, 52, 54) and comprising a gas jet body portion (34) mixing the fibers, a yarn channel (33) which is preferably cylindrical and extends from the body portion (34) and having a wire inlet and outlet end, at least one gas line (35) leading to the duct (33) through the body portion (34) and having an axis intersecting the longitudinal axis of the duct (33), a device for supplying a large amount of compressible gas under pressure in the conduit (35), a device (18, 20, 24, 22) that delivers the wire or wires (50, 52, 54) at a controlled speed to the inlet end of the channel (33), a device (40) 10 that removes the mixed wire (58); ) from its outlet end, a wire guide (30) between the wire feeder and the wire inlet end and forming a wire straight path between the guide and the wire inlet end, which track is coaxial with the channel (33), characterized in that the guide 15 consists essentially of a tube ( 30) with a longitudinal bore which is oriented substantially coaxially with the channel (33) and positioned along a straight path between the wire feeder and the wire inlet end, the outlet end of which is adjacent to the inlet end of the duct and long enough to substantially prevent jet-induced lateral vibrations of fibers in the wire upstream of the bore outlet end. Device according to Claim 5, characterized in that it has a single gas line (35) which intersects the duct (33) perpendicularly and whose cross-sectional area is substantially smaller than that of the duct. Device according to claim 5, characterized in that the length of said bore is at least 12.7 cm. Device according to claim 5, characterized in that the length of said bore is at least 25.4 cm. Device according to claims 7 and 8, characterized in that the ratio of the diameters of the wire channel (33) and the bore 35 is at least about 1.3: 1.0. Device according to Claim 9, characterized in that the outlet end of the borehole is separated from the inlet end of the channel (33) by a distance of 0.3175 to 1.27 cm. Device according to Claim 9, characterized in that the diameter of the bore is approximately 1.52 to 6.35 mm. Device according to Claim 6, characterized in that the wire feeder, the drilling, the channel and the wire discharge device form a continuous, straight wire path between the feed and discharge device. n 1 9 71 358