EP2881500A1 - Screen apron for fibre-condensing guides - Google Patents

Abstract

A wire mesh for a compression device of a spinning machine has a fabric of filaments and is at least in a fiber transport region (F) of the wire mesh (1) with a defined free surface (5) of at least 10% perforated to a Saugluftstrom (S) on a moving on it Fiber bundles (3) to act. The surface of the filaments contacting the fiber bundle (3) is flattened, at least in the fiber transport region (F), in comparison to a round surface, in order to facilitate an easier movement of the fiber bundle (3) on the surface of the wire mesh (1).

Description

A wire mesh for a compacting device of a spinning machine has a fabric of filaments and is perforated at least in a fiber transport region of the wire mesh with a defined free area of at least 10% to allow a suction air stream to act on a fiber bundle moved thereon.

The Siebriemchen is an elementary component of a compacting device in compact or compaction spinning machines. After passing through a conventional drafting system with a pair of output rollers, a stretched fiber bundle is taken from the wire mesh after leaving the pair of output rollers and transported by means of the driven Siebriemchens via a stationary suction slot. Vacuum acts on the fiber bundle through the suction slot and compacts it into a compact body. Projecting fibers are applied to the fiber bundle. Since the suction slot is usually inclined to the direction of movement of the wire mesh, a lateral relative movement of the fiber bundle is forced over the surface of the wire mesh. The fiber bundle curls up during this movement - it creates a false twist. In addition to the purely pneumatic compression thus an additional, mechanical compression is achieved.

The sieve strap prevents suction of fibers during compaction and guides the fibers over the suction slot. The Siebriemchens drive, for example, by a top roller with rubber cover, which presses the Siebriemchen against the surface of the compression device or against a suction tube and thus converts the rotational movement of the pressure roller in a revolution of the Siebriemchens. By pressing the Siebriemchens on the stationary compression device is subject to the Siebriemchen on the bottom of a wear, which In most applications, the service life of the wire mesh is determined.

In order to achieve a uniform circulation of the wire mesh around the compacting device, it is also necessary that the fabric of the wire mesh made of filaments has a certain resistance to displacement, which is determined by the bending and tensile strength of the filament and the weave of the fabric. If the resistance to displacement of the wire mesh is insufficient, the fabric may shift due to the friction between the wire mesh and the compacting device which fluctuates across the width of the wire mesh, resulting in a lateral drainage of the wire mesh or even wrinkling.

Especially when processing long staple material or when producing core-sheath yarns, wear on the surface of the sieve stitch may also occur. Since the fibers are clamped both between the pair of output rollers of the drafting system as well as at the drive point of the wire mesh, small deviations in the peripheral speeds can also lead to a longitudinal sliding of the fibers over the surface of the wire mesh, which causes the wire mesh to wear.

Another aspect for fabric construction is the energy requirement. Measurements have shown that with the same free area of the negative pressure loss in a coarse tissue is lower than in a fine tissue. Also, the increasingly local effect of the air flow on a coarse fabric does not seem to be a disadvantage. In order to achieve the best possible efficiency of the compacting device, therefore, the aim is to achieve as coarse as possible a tissue.

• Zum Erreichen einer möglichst guten Garnqualität muss das Siebriemchen so fein wie möglich und damit das Filament im Durchmesser so klein wie möglich sein.
• Zum Erreichen einer möglichst großen Standzeit und zum Erreichen einer möglichst guten Verschiebefestigkeit und eines guten Wirkungsgrads muss das Siebriemchen so grob wie möglich und damit das Filament im Durchmesser so groß wie möglich sein.

In summary, it can be stated that there are two conflicting requirements based on the experience gained regarding the fineness of the wire mesh:

• To achieve the best possible yarn quality, the sieve must be as fine as possible and thus the filament in the diameter as small as possible.
• To achieve the longest possible service life and to achieve the best possible displacement resistance and a good efficiency, the sieve must be as large as possible and thus the filament in diameter as large as possible.

Object of the present invention is therefore to be able to achieve the best possible yarn quality with a wear-resistant Siebriemchen as possible.

The object is achieved with a Siebriemchen with the features of independent claim 1.

An inventive wire mesh is provided for a compacting device of a spinning machine, in particular a compacting or compact spinning machine. The sieve strap has a fabric of filaments. The wire mesh is designed such that in a fiber transport region of the wire mesh a fiber bundle can be picked up by the wire mesh and transported together with the wire mesh to a delivery point of the fiber bundle. , is. The fiber transport region is seen transversely to the transport direction of the Siebriemchens the area in which a fiber bundle, which is received by the pair of output roller of the upstream drafting on the Siebriemchen and discharged again at the discharge point, or in other words, the area the fiber bundle travels on the sieve strap by its relative movement transversely to the longitudinal direction of the wire mesh. The fiber transport region is thus not defined solely by the transport movement of the fiber bundle, but because the fiber bundle usually also performs a relative movement transversely to the direction of movement of the sieve wire, the fiber transport region is also laterally fixed. The lateral boundary of the fiber transport region usually results from a suction slot, which is arranged in a suction tube below the wire mesh.

The sieve strap is perforated with a defined free space of at least 10%. This means that at least 10% of the Siebriemchens in the fiber transport area are permeable to air for acting below the Siebriemchens Saugluftstrom. The remaining surface of the wire mesh is covered by the filaments of the fabric and serves not to suction the fiber bundle moved on the wire mesh, but to retain the fibers of the fiber bundle, so that they are not sucked into the suction.

The suction slot can be arranged either parallel to the direction of movement of the wire mesh or inclined thereto in the suction pipe. As a rule, the suction pipe also serves to guide the wire mesh as well as a mating surface for a driven roller which moves the wire mesh. In addition, the Siebriemchen is usually endless. That is, the sieve strap formed a ring which is placed around the guide or the suction tube and constantly transported the incoming fiber bundle.

According to the invention, the surface of the filaments contacting the fiber bundle is flattened, at least in the fiber transport region, in comparison with a round surface of the filaments. As a result, in contrast to the filaments with a round surface, an easier movement of the fiber bundle on the surface of the wire mesh is made possible. A in particular transverse relative to the direction of movement of the Siebriemchens relative movement is thereby perform low-resistance. Thus, a better yarns can be created and beyond the wear of the Siebriemchens be reduced.

In a particularly advantageous embodiment of the invention, the flattened surface of the filaments is provided only on the upper side of the wire mesh. As a result, the yarn formation is advantageously influenced in particular. Alternatively, it is also possible for the filaments to have flattened surfaces both on the upper side and on the underside of the wire mesh. With this configuration of the filaments, a particularly advantageous influence on the wear of the wire mesh is to be taken.

While it is important to the effect on the yarn quality that the flattened surface be provided in the transport area of the wire mesh, it may be advantageous for the wire mesh itself if the flattened surface of the filaments is provided both in the fiber transport area and in the edge areas of the wire mesh are. There may be zones in which the surface of the filaments is not flattened and other zones in which it is flattened. Also, the flattening on the top and on the bottom can be provided differently or completely omitted in some areas. Also, of course, the complete Siebriemchen be provided only on the top or at the top and bottom with flattened filaments. In any case, it is important that the flattened surface of the filaments in the direction of the fiber bundle or in the direction of the support surface of the guide of the wire mesh, that faces away from the fiber bundle surface of the Siebriemchens to achieve the corresponding effect. If, in addition, there is also a flattening, which faces the adjacent filament of the fabric within the plane of the fabric, this is harmless, an effect on the movement, in particular the relative movement of the fiber bundle or the wear of the Siebriemchens is but only small.

In a particularly advantageous embodiment of the invention, since the surface of the Siebriemchens at least in the fiber transport area by machining, in particular by grinding, smoothed. The originally provided with a round surface filaments of the fabric are thereby removed, so that a flattened surface is formed.

If the surface of the filaments is calendered at least in the fiber transport region, this causes, for example, by means of a heat action, that the cross sections of the filaments are changed and thus have a flattened surface.

In a further advantageous embodiment of the invention, the filaments used in the fabric, in particular in the fiber transport region, are profiled. In this case, filaments are used which have a non-round profile already during their production or a corresponding post-processing prior to the production of the fabric. The profile is such that it has at least one flattened surface in the cross section of the filament. By appropriate processing into a fabric, a fabric can then be produced which has a flattened surface.

The profiled filaments preferably have a flattened, in particular oval or elliptical or substantially rectangular cross section. In this way, in contrast to a circular cross-section, a flattened cross-section can be produced which, when used appropriately in the fabric of the wire mesh, leads to a flattened surface of the fabric and thus of the wire mesh.

In a preferred embodiment of the invention, the filaments have a diameter between 30 .mu.m and 400 .mu.m. This allows fine and coarse fiber bundles are processed. In a particularly preferred embodiment, the filaments have a diameter of between 80 μm and 300 μm. These cross-sectional diameters provide the best compromise between good yarn production and a wear-resistant wire bond.

Preferably, the evacuated flank area in the fiber transport area is between 10% and 45% of the wire mesh in its fiber transport area. Thus, a sufficiently strong suction force is generated on the fiber bundle, which it pressed against the wire mesh and on the other hand, but also still allows the relative movement of the fiber bundle.

In a preferred embodiment of the invention, the filaments are fused together at least in the fiber transport region in the crossing points of the fabric and / or pressed or connected to each other by means of a positive connection. As a result, an additional strength of the fabric is produced, which prevents displacement of the fabric and thus ensures a long consistent quality when compacting the fiber bundle.

If the wire mesh is provided with a coating, in particular with a polymer, at least at the intersection points of the filaments, a rounding of the filaments and of the mesh openings or free surfaces of the fabric takes place in a particularly advantageous manner. By this rounding the wear of the Siebriemchens, the transport of the fiber bundle and the mobility of the fiber bundle across the Siebriemchen is further improved. The coating flows at the crossing points between the filaments and forms a skin-like layer. At the same time it can be effected that the filaments stick together by the coating and thus an additional strength of the fabric is achieved. The coating can be applied before and / or after the flattening of the filaments.

Figur 1

einen Ausschnitt eines feinen, herkömmlichen Siebriemchens mit einem Faserbündel über einem Saugschlitz,

Figur 2

einen Ausschnitt eines groben, herkömmlichen Siebriemchens mit einem Faserbündel über einem Saugschlitz,

Figur 3

ein erfindungsgemäßes Siebriemchen mit einem Faserbündel über einem Saugschlitz und

Figur 4

eine schematische Darstellung eines erfindungsgemäßen Siebriemchens über einem Saugrohr mit einem Saugschlitz.

Preferably, the filaments are fused or glued together at the edge regions of the wire mesh in order to avoid fraying of the wire mesh. The durability of the Siebriemchens is thereby improved. The border area is the area which is outside the area under which the suction slot exerts its suction force on the fiber bundle. The fusing or gluing can also take place in such a way that no or barely a suction force can be applied through the wire mesh more. The sieve strap can be completely or almost dense in these areas.
Further advantages of the present invention are described in the following exemplary embodiments. It shows:

FIG. 1

a section of a fine, conventional Siebriemchens with a fiber bundle on a suction slot,

FIG. 2

a section of a coarse, conventional Siebriemchens with a fiber bundle on a suction slot,

FIG. 3

an inventive Siebriemchen with a fiber bundle on a suction slot and

FIG. 4

a schematic representation of a Siebriemchens invention over a suction tube with a suction slot.

To better understand the invention, the operations on the surface of a wire mesh 1 are shown in a macro-perspective. FIG. 1 shows a section of a suction slot 2 with the overlying conventional fine Siebriemchen 1 and a fiber bundle arranged thereon 3. Due to the inclination of the suction slot 2 with respect to the direction of movement B of the wire mesh 1, a mechanical compression of the fiber bundle 3 is achieved. The fiber bundle 3 is located on one side or at an edge of the suction slot 2. Since the fiber bundle 3 by the suction air flow S is pressed onto the surface of the wire mesh 1 and the fiber bundle 3 is bulky and elastic, it partially immersed in the conditional by the binding of the tissue depressions. If the fiber bundle 3 now experiences a lateral relative movement R due to the inclination of the suction slot 2, then the fiber bundle 3 must overcome the elevations of the fabric. Like the representation of the FIG. 1 Assuming that overcoming the bond-related increases in the illustrated embodiment is not a very big problem.

Clearly different is the situation with a Siebriemchen 1 with a coarse, for example, 150 micron thick filament. The situation is in FIG. 2 shown. The fiber bundle 3 dives deep into the tissue-induced depressions of the tissue. To move the fiber bundle 3 laterally, an increased resistance is overcome.

In addition to the in the Figures 1 and 2 the influence of the binding on the lateral movement possibility of the already compacted fiber bundle 3, the fabric structure is also important when the fiber bundle 3 strikes the wire mesh 1. A broad fiber stream coming from the pair of drawing rollers, not shown, of the drafting system must be combined over the elevations of the fabric to form a compact fiber bundle 3. The elevations of the tissue also have a disadvantageous effect here.

In FIG. 3 a section of a Siebriemchens invention 1 is shown. The individual filaments of the wire mesh are flattened on their surface or on the top and bottom of the wire mesh 1 in the region of their bond. Some of the flats 6 are in the FIG. 3 drawn in and marked. The resistance of the fiber bundle 3 with a relative movement R is significantly lower in this embodiment than in the embodiments according to FIG FIG. 1 or in particular the FIG. 2 , The invention now reduces the bond-related elevations of a conventional one Tissue even when using a coarse filament to a minimum. The open spaces 5 can remain essentially the same.

• Kalandrieren des Siebriemchens 1 zwischen zwei Walzen, welche vorzugsweise beheizt sind
• Kalandrieren des Siebriemchens 1 durch Ultraschall mittels Sonotroden
• Kalandrieren des Siebriemchens durch Strahlung, vorzugsweise durch Wärmestrahlung
• Abtragen der Erhöhungen durch zum Beispiel Abschleifen der Siebriemchen 1 auf der Ober- und/oder Unterseite.

The reduction of the elevations or the flattening of the filaments can be achieved by calendering the wire mesh 1 or a similar, similar in effect method. Possible, for example:

• Calendering of the wire mesh 1 between two rolls, which are preferably heated
• Calendering of the Siebriemchens 1 by ultrasound by sonotrodes
• Calendering the Siebriemchens by radiation, preferably by thermal radiation
• Ablating the increases by, for example, grinding the Siebriemchen 1 on the top and / or bottom.

Basically, a flattening of the top of Siebriemchens 1 is sufficient to achieve an advantage over conventional Siebriemchen. The partial flattening of the yarn transport area is another production possibility - while the fabric is adjacent to the yarn transport area without flattening 6. Deviating from this, it may be due to the manufacturing process and the intention to achieve further advantages, that the wire mesh 1 is flattened on both the top and the bottom and across the entire width. It is also possible to flatten the wire mesh 1 only partially in the yarn transport area - either only on the top or on the top and bottom.

If flattening, in particular calendering, leads to a melting of the filaments at the crossing points of the fabric, In addition, an improvement in the displacement resistance of Siebriemchens 1 is achieved.

It is also conceivable to achieve a comparable effect by weaving a profile filament.

By the invention it is possible to use Siebriemchen 1 of coarse fabrics and to use filaments with large diameters. The demands for a good yarn quality, a long service life and a high energy efficiency are met simultaneously. By flattening the filaments, despite the coarse tissue, an improvement in the mobility of the fiber bundle is achieved, which can exceed the properties of a fine tissue.

FIG. 4 shows a portion of a suction tube 4, around which the Siebriemchen 1 is guided. The wire mesh 1 is driven in the direction of movement B by means of a pinch roller, not shown. It slides with its underside over the surface of the fixed suction pipe 4. The fiber bundle 3 passes to a not shown pair of output rollers of a drafting on the in the FIG. 4 shown right end of the suction slot 2 and is transported together with the wire mesh 1 in the direction of movement B. The suction slot 2 is vacuumed with negative pressure. This suction air stream S flows through the open spaces 5 of the wire mesh 1 and holds the fiber bundle 3 on the wire mesh 1 firmly. Due to the fact that the suction slot 2 is inclined to the direction of movement B, the fiber bundle 3 undergoes a relative movement in the direction of the arrow R perpendicular to the direction of movement B of the wire mesh 1. As a result, the fiber bundle 3 rolls or slides transversely to the direction of movement B of the wire mesh 1.

The inventive design of the wire mesh 1 in the fiber transport region F, in which the fiber bundle 3 is located, reduces the resistance of the wire mesh 1 to the fiber bundle 3. hereby The fiber transport region F is located substantially in the region of the wire mesh 1, which is arranged above the suction slot 2, or in the region where the fiber bundle 3 impinges on the wire mesh 1 to the point where the fiber bundle 3 leaves the wire mesh again. The lateral areas outside the fiber transport area 11 can also, as in FIG. 3 shown to be provided with flattened filaments. Alternatively, it is also possible to leave the filaments of the edge region conventionally, ie with a, for example, round cross-section.

The filaments generally have a diameter between 30 .mu.m and 400 .mu.m, preferably between 80 .mu.m and 300 .mu.m. The free surface 5 in the fiber transport region F is preferably between 10% and 45%.

The present invention is not limited to the illustrated embodiments. There are a variety of other shapes, in particular different flattenings 6 of the filaments, covered by the present invention. It is essential here that the filaments have a cross-section relative to a round cross-section, which allows the transverse movement of the fiber bundle 3 on the fabric with less resistance.

Claims (12)

Siebriemchen for a compacting device of a spinning machine, which has a fabric of filaments and at least in a fiber transport region (F) of the wire mesh (1) with a defined free surface (5) of at least 10% is perforated to a suction air flow (S) on a moving on it Fiber bundle (3) to act, characterized in that the fiber bundle (3) contacting surface of the filaments is formed flattened at least in the fiber transport region (F) compared to a round surface in order to facilitate, in contrast to round surfaces easier movement of the fiber bundle ( 3) on the surface of the sieve (1). Lattice apron according to the previous claim, characterized in that the flattened surface on the top or on the top and bottom of Siebriemchens (1) is provided. Siebriemchen according to one or more of the preceding claims, characterized in that the flattened surface in the fiber transport region (F) or in the fiber transport region (F) and the edge regions of the wire mesh (1) is provided. Lattice apron according to one or more of the preceding claims, characterized in that the surface at least in the fiber transport section (F) is smoothed by machining, in particular by grinding. Lattice apron according to one or more of the preceding claims, characterized in that the surface at least in the fiber transport section (F) is calendered. Siebriemchen according to one or more of the preceding claims, characterized in that the filaments are profiled. Lattice apron according to one or more of the preceding claims, characterized in that the filaments have a flattened, in particular oval or elliptical or essentially rectangular cross section. Lattice apron according to one or more of the preceding claims, characterized in that the filaments have a diameter of between 30 .mu.m and 400 .mu.m, preferably between 80 .mu.m and 300 .mu.m. Siebriemchen according to one or more of the preceding claims, characterized in that the free surface (5) in the fiber transport region (F) is between 10% and 45%. Siebriemchen according to one or more of the preceding claims, characterized in that the filaments are fused together at least in the fiber transport region (F) in the crossing points of the fabric and / or pressed or are connected to each other by means of a positive connection. Lattice apron according to one or more of the preceding claims, characterized in that the lattice apron (1) at least at the crossing points with a coating (11) is filled in particular with a polymer. Lattice apron according to one or more of the preceding claims, characterized in that the filaments at the edge regions of the Siebriemchens (1) fused together or glued, to avoid fraying of the Siebriemchens (1).

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