EP1493854A1 - Process and device for producing nonwovens - Google Patents

Abstract

An assembly (K) converts loose fibres into a non-woven web of varying thickness. The assembly has an all-steel opening cylinder (1) with air-driven fibre discharge to a sieve belt (9) that progressively accumulates fibres. The assembly further has a speed controller that alters the sieve belt speed with respect to the drum speed of rotation. The fibres are discharged by the sieve belt to a cross-layer fibre release arm that converts loose pile fibre to a fleece web. The control system regulates sieve belt speed in proportion to the cross-layer fibre release arm motion. Also claimed a commensurate process to produce a non-woven fibre web.

Description

In the manufacture of needle felts, a fibrous web taken from a carding machine, hereafter referred to as "batt", with the help of a crosslapper on a transversely to the feed direction of the fibrous web endlessly circulating support a multilayer nonwoven web, hereafter referred to as nonwoven fabric produced, which fed to a needle machine and there is solidified by needling.

It can be observed that even if the nonwoven produced by the stacker is uniformly thick over its entire width, so a constant at all points Basis weight has, the felt or velor web produced by the needle machine transversely to their direction uneven basis weight has. Its border area is thicker than hers Midrange.

To counteract this effect, from DE 37 38 190 C2 already a so-called profile formation become known, which consists in that one with the stacker a nonwoven web Uneven basis weight generates such that the nonwoven web in your Edge areas is thinner than in their middle area. For this it is again from DE 101 39 833 A1 and DE 201 13 467 U1 known, the Kreuzleger supplied card web on their way between the pile producer and the stacker or, as in DE 43 04 988 C1 described with the help of the Kreuzlegers in accordance with the laying movements of Kreuzlegers, cyclically stretch to in their thinning in a predetermined, regular Distance to be created, then from the stacker in the edge areas of the fibrous web produced nonwoven web are stored.

The stretching of the card web generates in this a reorientation of fibers, with the result that has the orientation of the fibers within the cross-laid nonwoven web transversely varies to the web direction, which in turn the stretch properties of the nonwoven web influenced by needling produced product. There are places in the finished product have track characteristics different from those of other places. In general, however, finished products are desired whose stretch characteristics the largely regardless of the stretch direction.

From WO 99/24650 has become known, the desired for the profile formation, cyclic, or in other words, as a repeat of recurring thin spots within a fibrous web by cyclically uneven removal of the pile from a pile producing the pile To create clutter. The required technology is very complicated and not at all Tile punching feasible.

The invention has for its object to provide a device and a method, with which a transversely profiled nonwoven web can be produced, the no Has fiber orientation disorders.

This object is achieved by the features specified in claim 1 and 7, respectively. advantageous Further developments of the invention are the subject of the dependent claims.

In the invention, the batt is formed by means of an aerodynamic pile generator. Aerodynamic pile generators are already known, for example, from DE 101 44 728 A1. The pile producer has facilities with the help of the Florabgabe in operation is changeable. The aerodynamic pile generator lays a batt that does not orientate has, so a random fiber pile, on an air-permeable surface from. In DE 101 44 728 A1 is said to be, whose conveying speed can be regulated by means of a control unit become.

While aerofoil-making is commonly used to produce high basis weight webs of up to 400 g / m ² which, because of this high basis weight, can be directly subjected to needling, water jet or thermobonding consolidation, the invention combines mechanical aerodynamic web production Web formation by crosslapping, for which purpose preferably thin webs with a basis weight of up to 20 g / m ² down aerodynamically generated. The random fiber pile is thus laid in a cross-lapper to a nonwoven web. As a result of the multiple paneling of the pile within the nonwoven fabric formed by crosslapping the card web, unwanted thickness fluctuations within the pile, if any, are averaged in accordance with the laws applicable at the cross cutting. The special feature of the invention, however, is that by appropriate control of Abfördergeschwindigkeit the pad on which the pile is stored in the aerodynamic Florerzeugung, in the formed goal web thick and thin areas can be generated at regular intervals, these distances from the Spreading width depends on crosslapping. By suitable adjustment of the cross-stacking movement, it is then possible in a known manner to ensure that the thin places of the card web are deposited in the edge regions of the nonwoven web produced, so that the desired thickness profile of the nonwoven web is seen in the transverse direction.

Of course it is also possible to create other profiles. That depends entirely on Distance between the thick and thin spots created in the card web and the control of the laying movement of the Kreuzlegers.

The cyclical change required for the particular application as described the basis weight of the aerodynamically generated card web is made by changing the speed of the air-permeable pad, preferably an endlessly circulating Sieve belt, which receives the fibers fed to it and the formed thereon card web transported away in the direction of the stacker. With uniform supply of fibers, i.e. Consistent per unit of time on the screen belt supplied amount of fiber, and changing The speed with which the screen belt rotates arises on the screen belt Florbahn whose basis weight inversely to the transport speed of the wire belt fluctuates. Due to the cyclic change in the transport speed of the screen belt Thus, a card web is produced, which has thin points, the regular distances from each other and which is suitable for the production of a profiled nonwoven web. The Unoriented fiber layer is in both the thick and in the thin areas of the card web available.

The aerodynamic pile generator can be fed directly from a feeder because it is due to its design to some extent also performs the function of a roller card and in some cases the quality requirements waiving the use of a separate one Allow clutter. In this context it has already been mentioned that Nonuniformities in the batt due to the effect of the crosslapper to some extent be compensated. Where on the other hand special quality is important, is the aerodynamic Florerzeuger preferably supplied by a roll card with fibers. Of the Florerzeuger then delivers despite the longitudinal orientation of the fibers in the of the carding given and supplied to him cardstock a Wirrfaserflor, because he the card pile completely dissolved in single fibers, which then aerodynamically without preferential direction on the air-permeable base are stored.

As the speed at which the stacker receives the fibrous web, in general does not coincide with the instantaneous speed with which the screen belt can be used, a cache can be used, they change over time Compensates for speed differences.

If one of the speeds of the feed roller and the sieve belt at the aerodynamic Flor producers in dependence on the laying movement of the Kreuzlegers regulates can to dispense with a pile storage between the pile producer and the stacker, However, it is then necessary that on the inlet side of the pile generator, a storage device is present, which takes into account the speed differences, with the pile producer receives the fiber material to be processed by him. One Speiser common design has such storage properties of home, so that with him there is no danger of it overflowing. A separate temporary storage device is then dispensable.

The achievable with the invention advantages are many. An important advantage over The prior art is that produces a completely unoriented fleece is that has no defects caused by distortion. Furthermore, the web formation in the simplest way possible. It may be available on separate buffers to compensate for differences in speed between those at the web formation participating units are dispensed with. It can be any fleece profile in the the crosslapper leaving nonwoven web are generated because only small machine masses for the purpose of profiling must be slowed down and accelerated. The Mass variation within the fiber web is greater because fiber mass is built up can. This is especially possible if no clutter as a feeding device for the aerodynamic pile generator is used, but this directly from a feeder is supplied. Is a clutter as a provider for the aerodynamic pile producer provided, one can by reducing the transport speed of the screen belt pile on this pulp.

Fig. 1

die Kernbaugruppe der vorliegenden Erfindung mit Ganzstahlgarniturwalze, Faserzuführeinrichtung und Siebband;

Fig. 2

eine Vorrichtung gemäß der Erfindung mit der Kernbaugruppe von Fig. 1, einem Speiser stromaufwärts und einem Kreuzleger stromabwärts davon;

Fig. 3

eine weitere Vorrichtung gemäß der Erfindung mit der Kernbaugruppe von Fig. 1, einem Speiser stromaufwärts und einem Zwischenspeicher sowie einem Kreuzleger stromabwärts davon, und

Fig. 4

eine weitere Vorrichtung gemäß der Erfindung mit der Kernbaugruppe von Fig. 1, einem Speiser und einer Walzenkrempelanordnung stromaufwärts sowie einem Florspeicher und einem Kreuzleger stromabwärts davon.

The invention will be explained in more detail with reference to embodiments illustrated in the drawings. It shows:

Fig. 1

the core assembly of the present invention with all-steel garnish roll, fiber feeder and screen belt;

Fig. 2

a device according to the invention with the core assembly of Figure 1, a feeder upstream and a stacker downstream thereof;

Fig. 3

a further device according to the invention with the core assembly of Figure 1, a feeder upstream and a buffer and a stacker downstream thereof, and

Fig. 4

a further device according to the invention with the core assembly of Fig. 1, a feeder and a roll carding arrangement upstream and a pile store and a stacker downstream thereof.

The core assembly K in the present invention of FIG. 1, a tangled fiber file producer, comprises a Ganzstahlgarniturwalze 1, the several provided with trims Abdeckmulden 2 face each other. The all-steel set roller 1 rotates at high speed, according to Fig. 1 in a clockwise direction. The cover troughs 2 are intended to rotate during rotation the all-steel garnish roll 1 to keep the fibers on this. The all-steel set roller 1 is on the inlet side a pair of feed rollers 3 and 4 opposite, which also with all-steel sets are provided and between them or together with the Ganzstahlgarniturwalze 1 each form a gap at the supplied fibers of the one Roller to be handed to the other. The upstream of the feed rollers, which in 1 is provided with the reference numeral 4, is a Florführungsmulde 5 opposite, the one with the circumference of the feed roller 4 in the direction of rotation of the feed roller. 4 forming narrowing gap. At the end of greater width of this gap is the drain side Guide roller 6 of an endlessly circulating conveyor belt 7 is arranged, which for feeding of fiber material from a feeder (not shown in Fig. 1).

The Ganzstahlgarniturwalze 1 is in a range in the direction of rotation of this roller. 1 located between the wells 2 and the feed roller 3, a scraper 8 opposite, below which there is an endlessly circulating sieve belt 9, which has several Deflection rollers 10 and 11 is guided. Under the upper run of the sieve belt 9, the Scraper 8 faces, there is an open-topped suction box 12 which is connected to a Vacuum source (not shown) is connected. Furthermore, a baffle 13 is to be mentioned, which is located in a sector between the wells 2 and the scraper 8 and delimiting a fiber flight channel extending from the all-steel clothing roll 1 toward extends to the portion of the upper run of the screen belt 9, which extends above the suction box 12 is located. In a space below the baffle 13 and above the Siebbandes 9 is a pressure roller 14, which with the screen belt 9 a gap formed.

By appropriate marking in sectors are in the drawing, the guide rollers. 6 and 10 characterized as having an individual drive means. These drive devices are connected to a control unit 15, which is shown in the drawing is indicated by corresponding connecting lines.

In operation of this device, one of a feeder (not shown) or a Carding (also not shown) dispensed and introduced via the feed belt 7 Fiber material in the narrowing gap between the first feed roller. 4 and the trough 5 introduced. Due to the all-steel set of feed roller 4 is the supplied fiber mass evened. It is from the first feed roller 4 of the adjacent and in the opposite direction of rotation rotating second feed roller. 3 pass and thereby evened out. From the second feed roller 3 are pass the fibers of the Ganzstahlgarniturwalze 1, which further uniformizes the pulp and isolated and the fibers with the help of the Abstreiters 8 aerodynamically deposits on the screen belt 9. The upper run of the screen belt 9 is by means of in the Suction box 12 prevailing negative pressure under suction, what the fiber deposit on the wire belt 9 favors and helps avoid flyaway. The fiber deposit on the screen belt 9 takes place completely undirected, i. the fibers within the formed on the wire belt 9 Flors have no preference orientation. The pile formed on the screen belt 9 is from Sieve belt, which revolves endlessly, transported away as a coherent card web.

When the fibers are fed from the feed belt 7 at a uniform speed, is also isolated with a uniform delivery of the Ganzstahlgarniturwalze 1 To count fibers on the wire 9. If then the transport speed of the Siebbandes 9 is changed, there is a change in the thickness of the on the wire belt 9 aerodynamically deposited fiber layer. With the help of the control device 15 and the From this influenced speed of the screen belt 9 can thus be in the formed on the wire belt 9 formed fiber web thick and thin spots.

Fig. 2 shows the application of this core unit K of FIG. 1 in an inventive Apparatus for producing a fibrous web. The aforementioned core unit K is located between a feeder 16 and a stacker 17, which on the screen belt 9 produced fiber web is fed. The stacker is designed here as a pier arm and will not be explained in detail. The Legearm the steep arm 17 leads above a take-off belt 18 a reciprocating motion. In the area of reversals of the laying arm of the steep arm 17, the speed of the Florabgabe must the discharge belt 18 reduced because of the necessary deceleration of Legearms to avoid unevenness of the pile storage. The transfer of fibrous web From the screen belt 9 to the steep arm 17 must therefore be adjusted accordingly. This can in the present case only by changing the transport speed of the screen belt 9, as a delay of the batt in the transfer area between the screen belt 9 and the Steilarmleger 17 must be avoided. To now undesirable To avoid variations in the thickness of the pile deposited on the wire belt 9, the feeding of fibers into the core unit K must be varied accordingly. This is done using the feed rollers 3 and 4. The resulting non-uniform Fiber demand of the core unit K is determined by that of the feeder 16 from home inherent storage capacity. The necessary vote of the Movement speed of the screen belt 9 with the laying movements of the Kreuzlegers 17 worried the controller 15th

It is understood that the laying motion of the laying arm of the stacker with the feeder the card web, taking into account the location of the thick and Thin points must be matched if a particular cross-section of the laid nonwoven web should be achieved. The necessary facilities are known and need therefore not to be explained here.

FIG. 3 shows a device comparable to that shown in FIG. 2, which is provided with a temporary store Z is supplemented. The buffer Z consists of an endlessly circulating second screen belt 19 and a storage roller 20, which is between the first wire 9 and the second screen belt 19 is arranged and stored on the first screen belt 9 card web decreases from there and deflects to the underside of the second screen belt 19, to which the Florbahn is sucked by a negative pressure, which in a between the two runs the second sieve belt 9 arranged suction box 21 prevails. The storage cylinder 20 is along the two sieve belts 9 and 19 movable and thus able to the length the located between the core unit K and the stacker 17 Florbahnabschnitts to change. An enlargement of this length causes a pile absorption, i. an intermediate storage, a reduction a corresponding Florabgabe from the Cache Z.

With the help of the buffer Z can be caused by the stacker 17 speed changes compensate for the infeed of the card web into the crosslapper 17, without something changed at the Florabgabe the core unit K on the first wire 9 something must become. The first screen belt 9 can, from the needs of a profile formation if necessary apart, be driven independently of the stacker 17.

The embodiment of FIG. 4 differs from the embodiment of FIG. 2 in that between the feeder 16 and the core unit K a roll card W with two customers and a buffer Z are arranged. The roll card W has an upper pickup 22 and a lower pickup 23. The lower pickup 23 lays the fibrous web removed from the carding drum 24 of the roll carding W on endless circulating pile conveyor belt 25. The upper loader 22 also places one Fibrous on an endless circulating transfer belt 26, the latter Flor on the Flortransportband already located on the pile 25 sets, of the lower Customer 23 comes. If a higher flange thickness is desired, can on the Krempeitambour 24 also more than two customers, for example, four customers, be present. The invention is not limited thereto.

The pile conveyor belt 25 is at the same time part of a buffer Z, to which a pile storage roller 20 heard between the Flortransportband 25 and the cache Z is arranged and along the Flortransportbandes 25 and the cache Z is movable. This storage roller 20 operates in the same manner as described with reference to Fig. 3 has been explained.

Expiration of the buffer Z is the feed belt 7, which is the lying on it Florbahn the core unit K feeds. The remaining elements of this arrangement are comparable to those in the previously described embodiments.

In operation, a fiber mass fed from the reservoir 16 is separated from the roll card transformed into a uniform pile, in two layers of the upper and lower Pickups 22 and 23 removed and placed on the pile conveyor belt 25. From there the double-ply card web is fed via the temporary storage Z to the core unit K, where they in the same manner as described with reference to FIG. 1, in individual fibers is dissolved, which are stored on the screen belt 9. It can by appropriate Control the running speed of the screen belt 9 to ensure that Thick areas and thin areas are produced in the produced random fiber web. As between the the card web generating core unit K and the stacker 17 no buffer is present, on the other hand, however, the Kreuzleger for the reasons mentioned a temporal has fluctuating pile requirements, the fiber feed must be in the core unit K in vote be controlled with the Florbedarf the Kreuzlegers 17. That means the feed in the core unit K must be varied in time. On the other hand, the roll card W the two card webs, which are superimposed on the pile conveyor belt 25, with constant speed and thickness. The difference between this constant Florabgabe of the roll card W and the pile recording at the core unit K is compensated by the buffer Z.

For the sake of clarity, FIGS. 2 to 4 refer to the representation of the control devices has been dispensed with for driving the various units. It should be noted that a speed modulation at the carding drum 24 and at the all-steel set roller 1 because of the large masses excreted, leaving alone the drives of feed rollers, storage roller and second screen belt 19 of the pile store into consideration come.

Claims (7)

Apparatus for producing a fibrous nonwoven web comprising an aerodynamic working device (K) for producing a fibrous web with over its length alternately thick and thin spots, with an all-steel set roller (1), the is arranged to disassemble a fiber material supplied to it in individual fibers and aerodynamically, an endlessly circulating screen belt (9), the Recording the aerodynamically supplied single fibers to build up the batt is arranged and arranged, and means (15), with which the rotational speed of the screen belt (9) relative to the feed rate of the All-steel garnish roll (1) supplied fiber material is changeable, and a downstream of the screen belt (9) arranged stacker (17) for receiving and crossing the batt into a fibrous web. Apparatus according to claim 1, characterized in that the device (15) is a control device for cyclically changing the rotational speed of the screen belt (9) relative to the feed rate of the Ganzstahigarniturwaize (1) supplied fiber material. Apparatus according to claim 1 or 2, characterized in that the screen belt (9) is part of an intermediate storage device (Z). Apparatus according to claim 1 or 2, characterized in that between the screen belt (9) and the stacker (17) is arranged a buffer. Device according to one of the preceding claims, characterized in that upstream of the Ganzstahlgarniturwalze (1) an intermediate storage device (Z) is arranged. Apparatus according to claim 5, characterized in that upstream of the temporary storage device (Z) a roller card (W) is arranged. A process for producing a nonwoven web whose both edge regions have a smaller thickness compared to the middle of the fibrous nonwoven web, consists of a fibrous web which alternately has thick and thin spots over its length and is zigzag-shaped so as to overlap partially so that its thin spots in the edge region protrude from their formed nonwoven web to come to rest, characterized in that with an all-steel garnish roll one of these fed fiber material disassembled into individual fibers and aerodynamically deposited as Flor on an endlessly rotating screen belt, from where the formed on the wire belt web of nonwoven web laying is supplied, and that the Circulation speed of the wire belt with respect to the feed rate of the Ganzstahlgarniturwalze supplied fiber material is cyclically changed.

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