EP2865792B1 - Drawing frame for an air spinning device - Google Patents

Description

The invention relates to a drafting system for an air spinning device for warping and compacting a sliver, with a drafting upstream of the supercharger and the drafting subsequent air spinning device, wherein in the main drafting zone upstream drafting zone of the drafting a second compressor is arranged.

The development of new spinning processes is significantly changing the requirement profile for machine elements, such as drafting systems. Each spinning process has specific requirements, some of which differ significantly from those of other spinning processes.

In ring spinning, a traditional spinning process, the yarn is solidified by true rotation of all the fibers about the longitudinal axis of the yarn. In the upstream drafting system, the sliver is often compacted in the individual drafting fields to integrate protruding fibers or fiber ends at the edge of the sliver in the sliver and to ultimately obtain a smooth, closed and uniform yarn with high strength and parallel fibers. By compacting the sliver, a higher strength and a lower hairiness of the ring yarn are achieved.

In the case of air-spinning, on the other hand, the yarn-forming process largely depends on how well it is possible to wind binder fibers in sufficient numbers and as regularly as possible around the core fibers. In today dominating jet spinning the emerging between the exit rollers of the drafting sliver passes through a nozzle block to the inlet opening of a hollow spinning spindle. Upon entry of the sliver into the spinning spindle, the free fiber ends are looped around the conically shaped spindle head of the spinning spindle by means of a circulating air flow and wrap themselves spirally around the screw during the drawing of the thread into the spindle mentioned core fibers. The core fibers form together with the so-called Umwindefasern a new thread, which is subtracted, monitored by a yarn cleaner, optionally cleaned and wound up.

Therefore, individual, protruding from the sliver fiber ends must be spread by means of an air flow, so that these Umwindefasern can wind around the untwisted core fibers. The force exerted by the wrapping on the yarn core normal force causes the Garnverfestigung by means of friction and leads to a compact and rough yarn with a good fiber orientation. The proportion of binder fibers of such a spun yarn is between 10% and 30%.

The warping of slivers in air spinning machines takes place at high overall distortions and high speeds. The total distortion is, for example, in excess of 180. For this purpose, air-spinning requires a drafting system for warping the sliver, which can handle a multiple of the fiber throughput of a conventional spinning process.

In a drafting system usually several consecutive pairs of rollers are arranged. Each of these roller pairs consists of a lower roller and an upper pressure roller. The sliver is transported through the pairs of rollers to the air spinning unit. Since the peripheral speeds of the roller pairs increase in the direction of fiber travel, also creates the so-called default.

The drafting system designation shows how many pairs of rollers the drafting system consists of. So there are three-roll, four-roll or five-roll drafting. For example, in a four-roller drafting system, as seen in the direction of fiber travel, the first two pairs of rollers form the biasing field; the section thereafter the intermediate drafting field and the last two pairs of rollers the main drafting zone.

In order to be able to produce a high-quality, air-spun yarn, the drafting system arranged directly in front of the air-spinning unit is of particular importance. Here it comes to a refinement and a further parallelization of the Fibers. The aim is to produce as uniform a sliver as possible in order to be able to spin a yarn that is as uniform as possible.

In the DE 38 37 070 A1 For example, an apparatus and method for producing a spun yarn with a pneumatic spinning machine will be described. By the device disclosed in this document, a variably adjustable compressed air flow is brought against the sliver at the entrance of the sliver in the spinning device and thereby causes a spreading of Faserendteilen the sliver, so that some of the fibers are wound around the core fibers at the edge of the sliver. In this way, the ratio of core fibers to binder fibers should be able to be influenced and thus also the properties of the yarn spun in this way. The strength of such a thread, for example, improves as the number of wraps around the outer circumference of the sliver increases.

The disadvantage of this approach is that the proportion Umwindefasern can not be controlled defined. The leadership of the fibers is also neglected, so that individual fibers can move away from the yarn axis, which means that they are insufficiently integrated into the yarn or even sucked directly and can no longer be used in the yarn composite for solidifying the yarn.

The DE 30 39 149 A1 discloses a high-distortion device in a spinning machine, with which stretching at high distortion ratio is feasible and in which a disturbance of the fiber assembly, such as the formation of flying fibers is prevented by air streams occurring and an abnormal expansion of the sliver width in the drafting zone. For this purpose, the device has a clamping and pressing device which presses at the front end of the Riemchenstreckwerkes running on both sides of the sliver stretch of the straps against each other and an offset terminal point at the front end of the Riemchenstreckwerks, so that the action of air currents in the Near the nip of the front rollers arise, is prevented.

Unfavorable in this solution is that here too the proportion of Umwindefasern not really Defined is influenced. Although the fibers are guided by the straps, the fibers on the straps nevertheless continue to expand in part. Wider fiber ribbons increase yarn hairiness and result in increased fiber output.

Furthermore, when the outer layer of the aprons is too thin, the guided fibers produce deformations of the surface of the apron, which in turn means that insufficient pressure can be applied to the fibers of the sliver.

By the DE 41 32 919 A1 is a device for influencing air currents on drafting rollers of spinning machines known. Before the drafting system and in each default field, a compressor is arranged. So that a sliver is not or only minimally exposed to the air currents caused by rotating rolls, a compressor with a partial shell for the rolls is used on the output rolls. At least one air channel and possibly also a blow-out channel are arranged in the jacket between the beginning of the jacket and the plane of the delay zone. In this way, the conveyed through the sliver in the gusset portion of the rollers air is removed and prevents cross-flow with Faserabspreizungen.

A disadvantage of the device is that the use of a compressor in the main draft zone compacts the fibers in the arresting point and reduces the proportion of edge fibers. Free fiber ends, which are actually needed after the delay at the entrance of the sliver in the spinning spindle for winding the core fibers are instead introduced into the compact sliver. In addition, the friction of the fibers on the wall of the third compressor adversely affects, which in turn impairs the yarn uniformity.

True, in the DE 41 32 919 A1 pointed out that for certain applications of the drafting system, such as in the false-wire air jet spinning, the compressor can be performed without lateral limitation of the sliver, but in this case has a disadvantageous that now the fibers are no longer out what a Broad running of the sliver and thus an increased fiber output due.

Based on the aforementioned prior art, the present invention seeks to further develop a drafting system for an air-spinning device so that the proportion of Umwindefasern can be improved.

This object is achieved by a drafting system for an air spinning device having the characterizing features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

To solve the problem, a third compressor is additionally arranged in a main drafting zone according to claim 1, the width of the passage cross-section greater, but not more than 10 mm larger than the width of the passage cross-section of the second compressor.

Due to this arrangement and design of the compressors, the fibers of the fiber sliver are compacted in the default drafting zone upstream default field and then fed to the main drafting zone.

Then, in the main drafting zone, the fibers are adequately guided by means of the third compressor, without the fiber sliver being further compressed, so that the edge fibers are still present when the sliver enters the spinning spindle and consequently can wind around the core fibers as binder fibers, so that the yarn In air spinning, the required strength is maintained and the substance utilization of the fibers is improved.

By means of the arrangement according to the invention a balanced relationship has been found between the compression of the sliver on the one hand and the guiding of the fibers on the other hand. Depending on how much the passage cross-section of the third compressor is greater than the passage cross-section of the second compressor, the proportion of edge fibers in the sliver and thus the proportion of Umwindefasern the air-spun yarn can be influenced. Furthermore, it was found in experiments that the inventive arrangement of the compressor in the drafting zones positively influences the air currents occurring there.

Which dimensions of the passage cross sections of the supercharger and the second compressor are selected depends on the amount of distortion and on the yarn count to be produced. The third compressor is selected depending on the second compressor and the desired proportion of the binder fibers in the finished spun yarn. In particular, the passage cross-section indicates the width of the passage of the compressor, the height of the passage is technologically less important.

If the passage cross-section of the third compressor is chosen to be substantially larger than the passage cross-section of the second compressor, but at most 10 mm larger, the sliver can run somewhat wider due to the larger passage cross-section and the proportion of edge fibers increases. The fiber output during spinning also increases slightly, but the spun yarn has a high proportion of binder fibers and has a high strength.

It has been found that a more than 10 mm larger passage cross-section of the third compressor in relation to the passage cross section of the second compressor is no longer able to perform the sliver sufficiently.

As described in claim 2, it is provided in a preferred embodiment that the passage cross-section of the third compressor is at least 1 mm larger than the passage cross-section of the second compressor.

With such a minimally larger passage cross section of the third compressor, it is ensured that, on the one hand, the sliver in the main drafting zone is not further compressed, while the fibers are, however, sufficiently guided. Edge fibers whose fiber ends protrude from the sliver are admitted to a small extent and can wind around the core fibers when the sliver enters the spinning spindle. In this way, only a minimal fiber output occurs during spinning and there is an air-spun yarn with a smaller, but sufficient proportion Umwindefasern.

The invention will be explained in more detail with reference to an embodiment shown in the drawings.

Figur 1

in Vorderansicht eine mit Luftspinnvorrichtungen ausgestattete Textilmaschine;

Figur 2

in Seitenansicht ein erfindungsgemäßes Vierwalzen-Streckwerk mit zugehöriger Spinnvorrichtung.

Figur 3

in Seitenansicht ein erfindungsgemäßes Dreiwalzen-Streckwerk

Figur 4

in Seitenansicht ein erfindungsgemäßes Fünfwalzen-Streckwerk

Show it:

FIG. 1

in front view of a textile machine equipped with air spinning devices;

FIG. 2

in side view, an inventive four-roller drafting system with associated spinning device.

FIG. 3

in side view of an inventive three-roller drafting system

FIG. 4

in side view, an inventive five-roller drafting system

The FIG. 1 schematically shows a front view of an air-spinning machine 1. These textile machines have a plurality of in series juxtaposed work or spinning stations 2, which are positioned between the end arranged so-called end racks 15, 16.

As in FIG. 1 further indicated, each of the jobs 2 with a template material, for example, a stored in a sliver can 3 sliver 4, equipped.

In addition, each of the jobs 2 has a drafting 5, an air-spinning device 6, a thread take-off device 7, a yarn cleaner 8 and a take-up device.

The associated thread-changing device 9 ensures that the yarn 10 produced in the air-spinning unit 6 from the sliver 4 is wound in intersecting layers onto a package 11.

This package reel or cross-wound bobbin 11 is, as usual, held in a coil frame, not shown, and is driven by a coil drive, also not shown rotates.

As in FIG. 1 further indicated, the jobs 2 of the textile machine 1 are preferably supplied by an automatically operating control unit 12, which, guided on rails 13, 14, along the work stations 2 is movable.

FIG. 2 shows a four-roller drafting 5 with downstream Luftspinnaggregat 6 and the passage of the sliver 4th

The withdrawn from the sliver can 3 sliver 4 is fed by a pre-compressor 17, which is upstream of the drafting 5, arranged by the set of feed rollers pair of top and bottom rollers 18, 19 and by means of the top and bottom rollers 20, 21; 23, 24; 28, 29 stretched. The upper and lower rollers 23, 24 cooperate with the straps 25, 26 together. The upper and lower rollers 28, 29 are arranged as output rollers.
Viewed in the fiber running direction, the first two pairs of rollers form the Vorverzugsfeld 30; the section thereafter, the intermediate drafting zone 31, in which the second compressor 22 is arranged, and the last two pairs of rollers, the main drafting zone 32 with a third compressor 27, whose passage cross section is greater than the passage cross section of the second compressor 22nd

The sliver 4 is through the pairs of rollers 18, 19; 20, 21; 23, 24; 28, 29 transported to the air spinning unit 6, wherein the peripheral speeds of the roller pairs increase in the direction of fiber travel. In the Vorverzugsfeld 30, the sliver is warped 3 to 6 times. In the intermediate drafting zone 31, the sliver 4 is compacted by means of the second compressor 22 and further warped. In the main drafting zone 32, the sliver 4 is guided by means of the third compressor 27, but not further compacted and moreover warped to its final fineness, which corresponds to the yarn count.

On the input side of the spinning unit 6, a nozzle device 42 is arranged.
The nozzles 43, 44 are connected via the line 45 to a compressed air source 46. The air flowing out of the nozzles 43, 44 generates a rotational flow, with which the stretched sliver 4 is acted upon. This is followed by a hollow spinning cone 47 connects.

The yarn 10 formed in the interaction of the nozzle device 42 and spinning cone 47 is withdrawn from the spinning unit 6 through the hollow spinning cone 47. The air chamber 48 surrounding the spinning cone 47 is connected to a vacuum source 50 by means of a further line 49. Further details of the spinning process by means of such spinning devices are for example the DE 199 26 492 A1 removable.

FIG. 3 shows a three-roller drafting system. The sliver 4 passes through the pre-compressor 17 and enters the drafting system 5. The feed roller pair 33 forms, with the middle roller pair 34, the pre-delay zone 36, in which the second compressor 22 is arranged. The following main drafting zone 37 is formed by the two, viewed in the fiber direction, rear roller pairs, the belt acting with intermediate roller pair 34 and the output roller pair 35. In the main drafting field 37, the third compressor 27 is arranged.

In FIG. 4 is a five-roller drafting system shown. Since a drafting system has already been described in detail, only the differences to the already made statements will be discussed here. The first bias field 56 is formed by the input roller pair 51 and the second roller pair 52. This is followed by a second pre-delay field 57, which is delimited by the second roller pair 52 and the third roller pair 53. Between the third roller pair 53 and the fourth roller pair 54 is the intermediate drafting zone 58 including the second compressor 22. The last draft zone is followed by the main drafting zone 59, which is formed by the fourth roller pair 54 acting with aprons and the pair of output rollers 55. In this main drafting zone 59, the third compressor 27 is arranged.

Claims (2)

1. Drafting arrangement (5) for an air spinning device (6) to draw and compress a fibre band (4), with a precompressor (17) arranged upstream of the drafting arrangement (5) and an air spinning device (6) following the drafting arrangement (5), a second compressor (22) being arranged in the draft zone of the drafting arrangement (5) arranged upstream of the main draft zone, characterised in that, in addition, arranged in a main draft zone (32, 37, 59) is a third compressor (27), of which the width of the through-cross section is greater, but a maximum of 10 mm greater, than the width of the through-cross section of the second compressor (22).
2. Drafting arrangement (5) for an air spinning device (6) according to claim 1, characterised in that the through-cross section of the third compressor (27) is at least 1 mm greater than the through-cross section of the second compressor (22).

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