METHOD FOR FORMING A FLEECE OF MULTIPLE PLY OF FIBERFLOWER BY MEANS OF A CROSS-BEARING, CROSS-BEARING AND ITS USE

Description

[0001] The invention relates to a method for forming a nonwoven fabric from several layers of fiber web by means of a cross-lapper, such a cross-lapper and its use, in detail according to the independent claims.

[0002] For the production of multi-layer nonwovens, carding systems followed by crosslappers are typically used. In the carding systems, fiber flocks are fed into the inlet side, separated down to the individual fibers, and discharged at the outlet side as an unbonded textile fabric, the fiber web.

[0003] The cross-lapper comprises at least one belt that conveys the fiber web from the inlet area of ​​the cross-lapper to a laying device. The laying device is designed to deposit the fiber web onto an outlet belt rotated by 90° to the inlet direction. The laying device can be designed as a laying arm, marketed, for example, as a Hyperlayer, or as a reciprocating laying carriage that deposits the fiber web onto the outlet belt at an angle of 90° to the inlet direction in a laying gap between two circulating belts. The resulting nonwoven fabric can then be bonded, for example, in a downstream needle loom, hydroentanglement, or thermal bonder.

[0004] The above-mentioned cross-stackers are known from EP 2 881 509 B1 and EP 1 854 910 B1.

[0005] In order to transfer the fiber web produced by the cross-lapper, for example, to the subsequent needling machine, a significantly narrower fiber web is required in order to be able to introduce the nonwoven to be needled into the needling machine and to start up the needling machine.

[0006] Therefore, so-called lead-in strips are used for the transfer. These are narrow strips that do not extend across the entire predetermined working width of the crosslapper and are formed at the beginning of the nonwoven / fiber web to be produced.

[0007] The present invention relates to such generic objects.

[0008] Such a narrow infeed strip can be conventionally produced using various methods, e.g., by partially extracting the fiber web, continuously reducing the extraction width, or by "blowing over" the fiber web into a triangle. Another option is to stop the entire system after deactivating the safety devices, manually forming an infeed wedge, and then restarting it after the system's safety has been restored. However, this generates waste in the form of the cut-out area of ​​the fiber web, and the system must be completely shut down.

[0009] When producing the insertion strip using suction, the fiber web must be divided into a portion to be suctioned off and a portion that remains on the transporting components. For fiber webs with low strength in the transverse direction, this separation is usually unproblematic. For fiber webs whose strength is also present in the transverse direction, such as cross-laid nonwovens that may already be pre-consolidated by a nonwoven stretcher, this separation does not work or is very unreliable. Furthermore, suction is problematic or even impossible with excessively high basis weights.

[0010] After the functional unit following the cross-stacker, such as the needle loom, has started up and is in its normal operation, the laying width is increased again starting from the insertion strip in order to produce the predetermined product-specific working width that is feasible with the cross-stacker.

[0011] It is therefore the object of the present invention to provide a method for forming a nonwoven fabric from multiple layers of fiber web using a cross-lapper, such a cross-lapper, and its use, which is improved over the prior art. In particular, it should be possible to produce an insertion strip for transferring the multi-layer fiber web laid in the cross-lapper to the downstream functional unit, such as a needle loom. This insertion strip does not require complex additional components such as fiber web extraction systems, which avoids fiber web waste, and does not require the system to be shut down.

[0012] This object is achieved by a method for forming a nonwoven fabric from multiple layers of fiber web using a cross-lapper, such a cross-lapper, and its use according to the independent claims. The dependent claims describe particularly useful embodiments of the invention.

[0013] In a method according to the invention for forming a nonwoven fabric from a plurality of layers of fiber web by means of a cross-lapper, by means of which a plurality of layers of fiber web are placed on top of one another to set a predetermined working width, the laying width of the laid fiber web is reduced to an insertion width by means of the cross-lapper in order to produce an insertion strip.

[0014] With the invention, the shortcomings known from the prior art can be circumvented by eliminating the need for splitting or partial suction of the fiber web. To achieve this, the cross-lapper initially does not lay down the full, predetermined working width, but rather only a narrow cross-lapped fiber web, the insertion strip, in a small laying width. This strip can be used for threading into the functional units following the cross-lapper in the working direction. Functional units following the cross-lapper can include, for example, a hydroentangling system, a needling machine, or a dryer.

[0015] The insertion strip is preferably produced on the operating side of the downstream functional units. This allows the operator to assist the insertion process manually. The insertion strip is formed on the operating side so that the operator can grasp the insertion strip if necessary without unlocking the safety devices. Following the threading process, the laying width of the cross-lapper and subsequently the web width are increased successively or with a selectable width increase until the full web width is reached.

[0016] Thus, with the invention, the lead-in strip itself is produced additively by the cross-stacker – during regular operation of the cross-stacker or the system, including the functional units downstream of the cross-stacker – and not cut from existing fiber web, as in the prior art, i.e., produced subtractively. Regular operation, or simply operation, describes the state in which the cross-stacker lays the predetermined working width, i.e., the lead-in strip has been successfully transferred to the downstream functional unit.

[0017] A lead-in strip is a strip of the fiber web or nonwoven to be produced—also known as a material web—whose width is smaller than the width of a fully spread material web. A fully spread material web has a predetermined working width. The latter can be defined by the physical characteristics of the cross-lapper and correspond to the maximum width that can be produced on the cross-lapper. The lead-in strip is used to transfer the material web between the functional units downstream of the cross-lapper. For example, the material web can be transferred from the cross-lapper to a subsequent needle-punching machine.

[0018] The term insertion width defines the width of the insertion strip that is less than the predetermined working width.

[0019] The term laying width describes the width of the fiber web that can be produced with the cross-lapper, which can be adjusted at least between the insertion width and the predetermined working width.

[0020] According to one embodiment, the insertion width can, for example, correspond to between 5% and 60% of the predetermined working width. This laying width is usually sufficient to insert the insertion strip into the downstream machines and to start these machines up and running. The predetermined working width can be reduced to the insertion width temporarily to produce the insertion strip. The duration can be sufficient to allow the functional units downstream of the cross-stacker to start up and begin operation.

[0021] The width of the insertion strip can vary in the longitudinal direction, in particular be characterized by a continuous change, or it can be kept constant over a predefined length range. In this way, with each additional layer of fiber web laid by the cross-stacker, the laying width can be increased starting from the insertion width until the predetermined working width is reached. The increase in laying width can be set from layer to layer, preferably between 30 mm and 500 mm. It has been shown that this is sufficient for most functional units connected to the cross-stacker to allow the insertion strip to be transferred and for them to start operation. Instead of increasing the laying width with each additional layer, the laying width can be increased step by step starting from the insertion width with each double layer of fiber web or a multiple of the double layer until the predetermined working width is reached.In an analogous manner, the increase in laying width per step can increase by at least 30mm.

[0022] The longitudinal direction refers to the direction of the nonwoven fabric being produced, which is perpendicular to the width direction of the nonwoven fabric. The longitudinal direction corresponds to the working direction of the cross-lapper. The working direction can be determined by the exit conveyor of the cross-lapper. The fiber web, or the nonwoven fabric being produced, passes through the cross-lapper in the working direction at a working line speed, namely when a predetermined working width of fiber web is being produced.

[0023] When the insert strip leaves the crosslapper and is transferred to the downstream functional unit, such as a needling loom or hydroentanglement, this line speed, which can be adjusted via the system's control system, must be reduced. As the laying width increases, the line speed increases. For example, during the production of the insert strip, the line speed of the web to be produced in the crosslapper is reduced from a working line speed to an insert line speed, with the line speed preferably being increased from the insert line speed towards the working line speed with each additional layer of fiber web. The speed at which the insert strip is formed is adjustable. The insert line speed can be a fraction of the working line speed, e.g. between 1% and 20% of the working line speed.

[0024] The invention also relates to a cross-lapper for forming a nonwoven fabric from several layers of fiber web, wherein the cross-lapper is configured such that it can carry out a method according to the invention.

[0025] The cross-lapper comprises at least one belt that conveys the fiber web from the inlet area of ​​the cross-lapper to a laying device. The laying device is designed to deposit the fiber web onto an outlet belt rotated by 90° to the inlet direction in order to deposit one layer of fiber web over the other. A control system configured to carry out a method according to the invention is assigned to the cross-lapper and actuates the laying device for producing the insertion strip in such a way that the laying width, starting from the predetermined working width, is reduced to the insertion width by means of the cross-lapper.

[0026] The laying device can be designed as a laying arm, marketed as a Hyperlayer, or as a reciprocating laying carriage that places the fiber web between two circulating belts in a laying gap at an angle of 90° to the infeed direction onto the outfeed belt. The resulting nonwoven can then be bonded, for example, in a downstream needle-punch machine, hydroentanglement, or thermal bonder.

[0027] The line speed of the system can be adjusted by means of the system control system, so that during the production of the insertion strip, starting from a working line speed, this is reduced to an insertion line speed, wherein preferably with each additional layer of fiber web, the line speed is increased again from the insertion line speed towards the working line speed.

[0028] The invention also relates to a combination—also called a system—of a cross-lapper according to the invention and functional units connected to the cross-lapper, such as a hydroentanglement system, a needling machine, or a dryer. The system also includes a tuft feeder with a downstream carding machine arranged upstream of the cross-lapper. Alternatively or additionally, the cross-lapper can also be fed with a fiber web from an upstream unwinding station.

[0029] Furthermore, the invention relates to the use of a cross-lapper, by means of which a nonwoven fabric can be formed from several layers of fiber web, for producing an insertion strip by reducing the laying width of the laid fiber web, starting from the predetermined working width, to an insertion width by means of the cross-lapper.

[0030] The present invention also provides a method for transferring several layers of a fiber web produced by means of a cross-lapper to a functional unit following the cross-lapper, comprising the following steps: a) producing an insertion strip by means of the cross-lapper by reducing the width of the laid fiber web with respect to the working width to an insertion width, b) transferring the insertion strip thus produced to the functional unit following the cross-lapper in the running direction of the fiber web, c) increasing the insertion width, preferably step by step, to the predetermined working width after transferring the insertion strip to the following functional unit.

[0031] In principle, what has been said with regard to the method according to the invention also applies analogously to the cross-stacker according to the invention.

[0032] The advantages of the invention will now be explained in more detail with reference to a preferred embodiment and the figures.

[0033] They show: Fig. 1 shows a schematic side view of a cross-lapper according to a possible embodiment; Fig. 2 shows a perspective view of a cross-lapper according to a possible embodiment; Fig. 3 shows a schematic representation of a transfer of a web from the cross-lapper to a functional unit downstream of it; and Fig. 4 shows a schematic representation of an alternative transfer of a web from the cross-lapper to a functional unit downstream of it.

[0034] In the Fig. 1 and 2 The principle of a cross-lapper 1 is shown by way of example and only schematically, in which the laying device is formed by a laying carriage. Alternatively, the laying device can be formed by a laying arm. A carding system 17 ( Fig. 3) produced fiber web 3 is transported to an infeed belt 2 of the cross-stacker 1. Within the cross-stacker 1, an upper carriage is arranged, of which only one deflection roller 6 is visible in this illustration. Furthermore, the cross-stacker 1 has a laying carriage, of which a laying roller 10 for a counter belt 13 and a laying roller 9 for the infeed belt 2 are shown. Between the laying roller 10 of the counter belt 13 and the laying roller 9 of the infeed belt 2, the so-called laying gap 11 is arranged, from which the fiber web 3 emerges and is deposited on an outlet belt 15 arranged below the laying carriage. Both laying rollers 9, 10 take on the task, depending on the direction of travel, of laying the fiber web 3 orthogonally to the previous running direction (see the bold arrows in Fig. 3 ) onto an outlet belt 15 arranged below the laying carriage and folding them. Fig. 3The folding is indicated by the diagonal lines in the fleece 18 made from several layers of fiber pile 3. For this purpose, the laying carriage moves as shown in the Fig. 1 and 2 indicated by the double arrows, permanently back and forth in the horizontal direction over a preset laying width, here for example the predetermined working width.

[0035] In this embodiment, the infeed belt 2 is deflected around a first and second deflection roller 4, 5 and around a deflection roller 6 of the superstructure. A cover belt 7 can be arranged above the infeed belt 2, which in this illustration is guided around a deflection roller 8, a deflection roller 6 of the superstructure, and another deflection roller 12. Both belts 2, 7 can be designed as endless belts that are driven by at least one additional deflection roller (not shown). Other design variants, in which the laying carriage interacts not with the infeed belt 2 but with another belt, are possible and known.

[0036] In this embodiment, the infeed belt 2 and the cover belt 7 do not run parallel, but rather form an acute angle open towards the carding system 17, into which the fiber web 3 is drawn in and slightly compacted. The fiber web 3 is guided around the deflection roller 6 of the superstructure, with the cover belt 7 being guided laterally by means of the deflection roller 12. The fiber web 3 is transported in exactly the opposite direction, as it is guided 180° around the deflection roller 6 of the superstructure and deposited onto a counterbelt 13 arranged parallel below the infeed belt 2. The counterbelt 13 and the infeed belt 2 now clamp or guide the fiber web 3 together to the laying gap 11, which is essentially formed by the distance between the two laying rollers 9 and 10 of the laying carriage. The fiber web 3 emerges from the laying gap 11 and is laid onto an outlet belt 15 arranged below the laying gap 11.The laying carriage thus continuously moves in a horizontal reciprocating direction across the width of the discharge belt 15, onto which the fiber web 3 is laid and folded. Subsequently, the fiber web 3 or the fleece 18 (. Fig. 3 ) on the discharge conveyor 15 in the working direction 14 (direction of the arrow) to the functional unit 19 following the cross-stacker 1 (see Fig. 3 ) continued to be promoted.

[0037] The inlet belt 2, the cover belt 7, and the counter belt 13 can be designed as endless belts, with the cover belt 7 and the counter belt 13 being designed to be permeable to allow air to escape. A cost-effective embodiment is the use of a perforated belt. A preferred embodiment is the use of a sieve belt.

[0038] Both the infeed belt 2 and the cover belt 7 have the same running direction for the fiber web 3 and typically the same speed. To a certain extent, the fiber orientation on the surface relative to the neutral fiber of the fiber sliver can be influenced if both belts 2, 7 are operated at slightly different speeds.

[0039] To now, as in Fig. 3 shown, to transfer the nonwoven fabric 18 produced in the cross-lapper 1 by laying the fiber web 3 to the subsequent functional unit 19, an insertion strip 16 is produced by means of the cross-lapper 1 before the transfer. The insertion strip 16 is thereby removed from the cross-lapper 1, as with reference to the Fig. 1 and 2 already explained, by laying individual layers of fiber web 3 on top of each other. For this purpose, the laying width of the fleece 18, i.e. the laid fiber web 3, is determined starting from the predetermined working width (in Fig. 2shown in dashed lines) to an insertion width. This can be the first in Fig. 3 shown and thus narrowest section of the insertion strip 16. Its width corresponds to the insertion width, which is a fraction of the predetermined working width.

[0040] After laying another layer of fiber web 3 onto the discharge belt 15, the laying width can be increased again starting from the infeed width until the predetermined working width is reached. This results in, as shown in Fig. 2 indicated a wedge or triangle on fleece 18 which essentially increases in width from its insertion width. This wedge results from the increase in the laying width from layer to layer, as in Fig. 3In this way, for example, in a first step, the laying width of the fiber web 3 can be set to a 1000 mm insertion width, and this can then be widened from layer to layer of the fiber web 3 by, for example, 30 mm to 500 mm. This results in the predetermined working width of, for example, 4500 mm after just seven layers.

[0041] In principle, it would also be possible to produce the insertion strip 16 not wedge-shaped or triangular, but rectangular, i.e., with a constant insertion width from layer to layer. Laying the insertion strip 16 using the cross-lapper 1 results in significantly less wasted nonwoven 18. For example, starting with an insertion strip 16 with a width of 500 mm, the full working width of 4500 mm can be achieved with a single jump.

[0042] In Fig. 4An alternative embodiment of the transfer of the web 18 from the cross-lapper 1 to the subsequent functional unit 19 is shown. The insertion strip 16 is thereby transferred from the cross-lapper 1, as described with reference to the Fig. 1 and 2 already explained, by laying individual double layers of fiber pile 3 on top of each other. For this purpose, the laying width of the fleece 18, i.e. the laid fiber pile 3, is determined starting from the predetermined working width (in Fig. 2 shown in dashed lines) to an insertion width. This can be the first in Fig. 4 shown and thus narrowest section of the insertion strip 16. Its width corresponds to the insertion width, which is a fraction of the predetermined working width.

[0043] After laying another double layer of fiber web 3 onto the discharge belt 15, the laying width can be increased again starting from the infeed width until the predetermined working width is reached. This results in, as shown in Fig. 2indicated a wedge or triangle on fleece 18 which essentially increases in width from its insertion width. This wedge results from the increase in the laying width from double layer to double layer, as in Fig. 4 In this way, for example, in a first step, the laying width of the fiber pile 3 can be set to a 1000 mm insertion width, and this can then be widened step by step, in this case from double layer to double layer of the fiber pile 3, by e.g. 30 mm to 500 mm.

[0044] The present invention thus makes it possible to transfer the fiber web 3 or nonwoven 18 produced by means of a cross-lapper 1 to a functional unit 19 following the cross-lapper, for example, a needle loom, hydroentanglement machine, or thermal bonder. After the insertion strip 16 has been produced, the latter is transferred to the subsequent functional unit 19, and the insertion width is then increased to the predetermined working width. During the production of the insertion strip 16, the line speed of the nonwoven 18 to be produced in the cross-lapper 1 is reduced from a working line speed to an insertion line speed. This is achieved via the control system of the entire system.

[0045] A control system 20 can be assigned to the cross-stacker 1, which is configured to carry out the method according to the invention and preferably actuates the laying carriage for producing the insertion strip 16 in such a way that the laying width, starting from the predetermined working width, is reduced to the insertion width by means of the cross-stacker. The control system 20 of the cross-stacker 1 is controlled by a higher-level control system of the entire system, since the upstream tuft feeders, carding system 17, or unwinding stations must also be simultaneously reduced in speed and later increased. The same applies to the downstream functional units 19.Likewise, the line speed of the outlet belt 15 can be adjustable by means of the control 20, so that during the production of the insertion strip 16, starting from the working line speed, this is reduced to the insertion line speed, wherein preferably with each additional layer of fiber web 3, the line speed is increased again starting from the insertion line speed towards the working line speed. Reference symbol

[0046] 1 Crosslapper 2 Infeed conveyor 3 Fiber pile 4 First deflection roller 5 Second deflection roller 6 Deflection roller upper carriage 7 Cover conveyor 8 Deflection roller 9 Laying roller 10 Laying roller 11 Laying gap 12 Deflection roller 13 Counter conveyor 14 Working direction 15 Outfeed conveyor 16 Infeed strip 17 Carding system 18 Fleece 19 Functional unit 20 Control system

Claims

1. A method for producing a web (18) from a plurality of layers of fibre mat (3) by means of a crosslapper (1), using which a plurality of layers of fibre mat (3) are laid one on top of the other to achieve a predetermined working width, where, to produce an insertion strip (16), the width of the laid fibre mat (3) is reduced to a guide width, starting from the predetermined working width, using the crosslapper (1).

2. A method according to claim 1, characterised in that the insertion width corresponds to between 5% and 60% of the predetermined working width.

3. A method according to claim 1 or 2, characterised in that the reduction of the predetermined working width to the insertion width is carried out periodically to produce the insertion strip (16).

4. A method according to one of claims 1 to 3, characterised in that with each further layer of fibre mat (3) the width of the fibre mat is increased, starting from the insertion width, until the predetermined working width is reached.

5. A method according to claim 4, characterised in that the increase in width of the fibre mat increases by at least 30 mm with each layer.

6. A method according to one of claims 1 to 3, characterised in that with each dual layer of fibre mat (3) or multiple dual layers, the width of the fibre mat is increased in steps, starting from the insertion width, until the predetermined working width is reached.

7. A method according to claim 6, characterised in that the increase in width of the fibre mat increases by at least 30 mm per step.

8. A method according to one of claims 1 to 7, characterised in that the line speed of the web (18) to be produced in the crosslapper (1) is reduced while the insertion strip (16) is being produced, starting from a working line speed to an insertion line speed, where preferably the line speed is increased with each additional layer of fibre mat (3), starting from the insertion line speed in the direction of the working line speed.

9. A crosslapper (1) for forming a web (18) from a number of layers of fibre mat (3), wherein the crosslapper (1) is set up to carry out a method according to one of the preceding claims.

10. Crosslapper (1) according to claim 9, characterised in that the crosslapper (1) comprises at least one belt conveying the fibre mat (3) from the feed area of the crosslapper (1) to a stacking device, wherein the stacking device deposits the fibre mat (3) on an output conveyor (15) and can be moved back and forth along a predetermined working width in order to deposit one layer of fibre mat (3) on top of the other, the crosslapper (1) being assigned a control system (20) which is set up to carry out a method according to one of claims 1 to 6, and preferably operates the stacker device for producing the insertion strip (16) in such a way that the stacking width is reduced from the predetermined working width to the insertion width using the crosslapper (1).

11. Crosslapper (1) according to claim 10, characterised in that the stacker is designed as a stacker carriage or as a stacker arm.

12. A crosslapper (1) according to claim 10, characterised in that the line speed of the output conveyor (15) can be adjusted by means of the control system (20) so that, during the production of the insertion strip (16) starting from a working line speed which is reduced to an insertion line speed, with the line speed preferably being increased again in towards the working line speed with each further layer of fibre mat (3), starting from the insertion line speed.

13. A crosslapper (1) according to claim 10, characterised in that the control system (20) of the crosslapper (1) is activated by a system control for the production of the web to change the operating speed.

14. Use of a crosslapper (1) by means of which a web (18) can be formed from a plurality of layers of fibre mat (3), for producing an insertion strip (16), by reducing the stacking width of the stacked fibre mat (3) from the predetermined working width to an insertion width using the crosslapper (1).