Method for forming a nonwoven fabric made of a multilayer fiber web by means of a cross-lapper, a cross-lapper and its use

Abstract

The present invention relates to a method for forming a nonwoven fabric made of a multilayer fiber web by means of a cross-lapper, wherein a plurality of layers made of a fiber web are laid one on top of the other by means of the cross-lapper in order to adjust a predetermined working width, wherein the laying width of the laid fiber web is reduced by means of the cross-lapper from the predetermined working width to an introduction width in order to produce an introduction strip. The invention also relates to such a cross-lapper and its use.

Description

Technical Field

[0001] In particular, according to the independent claims, the invention relates to a method for forming a nonwoven fabric made of a multilayer fiber web by means of a crosslapper, and also to such a crosslapper and its use. Background Art

[0002] To produce multi-layer nonwovens, carding systems with a downstream crosslapper are usually used. When using such carding systems, loose fibers are fed in on the input side, which are loosened into individual fibers and discharged on the output side as an unconsolidated textile planar structure, i.e., a fiber web.

[0003] A cross-lapper includes at least one conveyor belt that transports the fiber web from the cross-lapper's input area to a laying device. The laying device is designed to deposit the fiber web onto the delivery belt, rotated 90° relative to the input direction. The laying device can be configured as a laying arm, commercially available as a Hyperlayer, for example, or as a reciprocating laying carriage that deposits the fiber web onto the delivery belt in the laying gap between two rotating conveyor belts at a 90° angle relative to the input direction. The resulting nonwoven fabric can be reinforced, for example, in a downstream needleloom, water jet consolidation system, or thermobonding machine.

[0004] Crosslappers of the aforementioned type are known from EP 2 881 509 B1 and EP 1 854 910 B1.

[0005] In order to convey a fiber web produced by means of a crosslapper, for example, to a downstream needling machine, a significantly narrower fiber web is necessary in order to be able to introduce the nonwoven to be needled into the needling machine and to start the needling machine.

[0006] In order to complete the transportation, a so-called introduction strip is therefore used. Here, it is a narrow strip that does not extend over the entire predetermined working width of the cross-lapper and is constructed at the beginning of the nonwoven / fibrous web to be produced.

[0007] The present invention relates to objects of this type.

[0008] Conventionally, such narrow introduction strips can be produced using various methods, for example, by partially suctioning the web, with the suction width continuously decreasing, or by "overblowing" the web into a triangular shape. Alternatively, it is possible to shut down the entire system after deactivating the safety device, manually shape the feed wedge, and then restart the system once safety has been restored. However, in this case, waste is deposited in the shape of the cut surface of the web, and the system must be completely shut down.

[0009] When producing the introduction strip by suction, the fiber web must be divided into a portion to be suctioned and a portion remaining on the transport element. This division is generally not a problem if the fiber web has low transverse strength. However, if the fiber web has transverse strength, such as with cross-laid nonwovens that have been pre-consolidated by a nonwoven draw frame, this division is no longer effective or only works very unreliably. Furthermore, if the weight per unit area is too high, suction becomes problematic or even impossible.

[0010] After the functional units arranged downstream of the crosslapper, such as the needle loom, have been started, ie in their normal operation, the laying width is increased again starting from the introduction of the strip in order to produce a predetermined product-specific working width that is feasible with the crosslapper. Summary of the Invention

[0011] The object of the present invention is therefore to provide a method for forming a nonwoven fabric made of a multi-layered fiber web using a cross-lapper. The invention also relates to such a cross-lapper and its use, which are improved compared to the prior art. In particular, it is possible to produce an introduction strip for conveying the multi-layered fiber web laid in the cross-lapper into a downstream functional unit, such as a needle loom, without requiring costly additional components such as a suction device for the fiber web, without causing any fiber web scrap to accumulate, and without requiring the system to be shut down.

[0012] This object is achieved by a method for forming a nonwoven fabric made of a multilayer fiber web by means of a crosslapper, a crosslapper and its use according to the independent claims. The dependent claims describe particularly advantageous embodiments of the invention.

[0013] In the method according to the invention for forming a nonwoven fabric made of a multilayer fiber web with the aid of a cross-lapper, a plurality of layers made of a fiber web are placed one on top of another with the aid of a cross-lapper in order to adjust a predetermined working width, wherein, for the production of an introduction strip, the laying width of the laid fiber web is reduced from the predetermined working width to the introduction width with the aid of the cross-lapper.

[0014] The present invention avoids the drawbacks known from the prior art, making the web division or partial suctioning completely unnecessary. To this end, the cross-lapper should also not deposit the entire predetermined working width, but rather only deposit a narrow cross-lapped web within a small lay width, i.e., an introduction strip, which can be used to feed a functional unit connected to the cross-lapper in the working direction. Functional units connected to the cross-lapper can be understood as, for example, a water jet consolidation system, a needle loom, or a dryer.

[0015] The introduction strip is preferably produced on the operator side of the subsequent functional unit. This allows the operator to manually support the introduction process. The introduction strip is designed on the operator side so that the operator can, under certain circumstances, grasp the introduction strip without releasing the safety device. Immediately after the threading process, the laying width of the crosslapper and the width of the nonwoven fabric are continuously and gradually increased, or in selectable width increments, until the full nonwoven fabric width is reached.

[0016] Thus, with the present invention, the lead-in strip itself is produced additively by the cross-lapper—and this is done during normal operation of the cross-lapper, or during normal operation of a system including a functional unit arranged downstream of the cross-lapper—rather than being cut from an existing fiber web, i.e., formed subtractively, as in the prior art. Normal operation, or simply operation, describes the state in which the cross-lapper lays the predetermined working width, i.e., the lead-in strip has been successfully transferred to the subsequent functional unit.

[0017] The lead-in strip is the strip of fibrous web or nonwoven fabric to be produced, also called the material web. Its width is smaller than the width of the material web running at full width. The material web running at full width has a predetermined working width. This width can be defined by the physical conditions of the cross-lapper and corresponds to the maximum width that can be produced on the cross-lapper. The lead-in strip is used to transport the material web between the cross-lapper and downstream functional units. This allows, for example, the material web to be transported from the cross-lapper to a connected needling machine.

[0018] The term lead-in width defines the width of the lead-in strip, which is smaller than the predetermined working width.

[0019] The term lay width describes the width of the nonwoven web that can be produced using a crosslapper, which is adjustable at least between an introduction width and a predetermined working width.

[0020] According to one embodiment, the introduction width corresponds, for example, to between 5% and 60% of the predetermined working width. This laying width is at least sufficient to introduce the introduction strip into the subsequent machines and to operate them. The predetermined working width can be temporarily reduced to the introduction width in order to produce the introduction strip. A time duration can also be set to activate and operate the functional units arranged after the crosslapper.

[0021] Here, the width of the introduction strip, viewed in the longitudinal direction, is variable and is characterized in particular by a continuous change or by being held constant within a predefined length range. The laying width can thus be increased from the introduction width with each additional layer of the fiber web laid by the cross-lapper until a predetermined working width is reached. The increase in the laying width from one layer to another can be adjusted, preferably between 30 mm and 500 mm. It has been shown that this is sufficient for most functional units connected to the cross-lapper in order to be able to transport the introduction strip and to enable the functional units to be operational. Instead of the laying width increasing with each additional layer, the laying width can be increased stepwise from the introduction width with every two layers or multiples of two layers of the fiber web until a predetermined working width is reached. In a similar manner, the increase in the laying width can be increased by at least 30 mm per step.

[0022] The longitudinal direction refers to the direction of the nonwoven fabric being produced, perpendicular to the width of the nonwoven fabric. This direction corresponds to the working direction of the crosslapper. The working direction can be predetermined by the crosslapper's delivery belt. The fiber web or nonwoven fabric to be produced travels through the crosslapper in the working direction and at the working line speed, i.e., while producing the predetermined working width of the fiber web.

[0023] After leaving the crosslapper, the line speed (which can be adjusted by the machine's controller) must be reduced when the lead-in strip is transported to subsequent functional units, such as a needleloom or water jet consolidation system. The line speed increases with increasing lay width. Thus, when producing the lead-in strip, the line speed of the nonwoven fabric to be produced in the crosslapper decreases from the operating line speed to the lead-in line speed, preferably increasing from the lead-in line speed to the operating line speed with each additional layer of the web. The speed at which the lead-in strip is formed is adjustable. The lead-in line speed can be a fraction of the operating line speed, for example, between 1% and 20% of the operating line speed.

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

[0025] The cross-lapper comprises at least one belt that transports the fiber web from an input area of ​​the cross-lapper to a laying device. The laying device deposits the fiber web on an output belt, rotated 90° relative to the input direction, so that one layer of fiber web is deposited on top of another. The cross-lapper is assigned a controller that is configured to carry out the method according to the invention and preferably operates the laying device to produce an incoming web, such that the laying width is reduced by the cross-lapper from a predetermined working width to an incoming width.

[0026] The laying device can be designed as a laying arm, which is commercially available as a super layer, or as a reciprocating laying carriage that deposits the fiber web onto the delivery belt in the laying gap between two circulating conveyor belts at a 90° angle to the delivery direction. The nonwoven fabric produced in this way can be consolidated and strengthened in a subsequent needleloom, water jet consolidation system, or thermobonding machine, for example.

[0027] Here, the line speed of the device can be adjusted by means of a device controller so that during the production of the introduction strip, the line speed is reduced from the working line speed to the introduction line speed, wherein the line speed is preferably increased again from the introduction line speed to the working line speed with each additional layer of the fiber web.

[0028] The present invention also relates to a combination, also referred to as an apparatus, comprising a cross-lapper according to the invention and a functional unit connected to the cross-lapper, such as a water jet consolidation device, a needle loom, or a dryer. This apparatus also includes a bulk fiber feeder with a downstream carding machine, which is arranged upstream of the cross-lapper. Alternatively or additionally, the cross-lapper can also be fed with a fiber web via an upstream opening station.

[0029] The invention further relates to the use of a cross-lapper, with the aid of which a nonwoven fabric made of a multi-layer fiber web can be formed by reducing the laying width of the laid fiber web from a predetermined working width to an introduction width by means of the cross-lapper in order to produce an introduction strip.

[0030] The present invention also provides a method for conveying a multi-layer fiber web produced by means of a cross-lapper to a functional unit connected to the cross-lapper, comprising the following steps:

[0031] a) producing an introduction strip by means of a cross-lapper by reducing the width of the laid fiber web relative to the working width to the introduction width,

[0032] b) conveying the thus produced lead-in strip to a functional unit located downstream of the crosslapper in the direction of travel of the fiber web,

[0033] c) After the introduction strip has been conveyed to the downstream functional unit, the introduction width is preferably increased stepwise to a predetermined working width.

[0034] The subject matter described with respect to the method according to the invention is essentially the same as that of the cross-lapper according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The advantages of the present invention will now be further illustrated with reference to preferred embodiments and the accompanying drawings.

[0036] In the picture:

[0037] Figure 1 shows a schematic side view of a crosslapper according to one possible embodiment;

[0038] Figure 2 shows a perspective view of a crosslapper according to one possible embodiment;

[0039] Figure 3 A schematic diagram showing a way of conveying a nonwoven fabric from a cross-lapper to its downstream functional units, and

[0040] Figure 4 A schematic diagram shows another way of conveying a nonwoven fabric from a crosslapper to its downstream functional units. DETAILED DESCRIPTION

[0041] Figure 1 and Figure 2 The principle of the cross-lapper 1 is shown by way of example and only schematically, wherein the laying device is constructed by a laying carriage. Alternatively, the laying device can also be constructed by a laying arm. Figure 3 ) is transported to the input belt 2 of the cross-lapper 1. An upper carriage is provided in the cross-lapper 1, but only its deflection roller 6 can be seen in the figure. In addition, the cross-lapper 1 has a laying carriage, from which a laying roller 10 for the mating belt 13 and a laying roller 9 for the input belt 2 are shown. The so-called laying gap 11 is arranged between the laying roller 10 of the mating belt 13 and the laying roller 9 of the input belt 2, from which the fiber web 3 is moved out and placed on the output belt 15 arranged below the laying carriage. The two laying rollers 9, 10 have the task of laying the fiber web 3 orthogonally to the previous direction of travel (see Figure 3 The bold arrow in the middle is placed on the output belt 15 arranged below the laying carriage and folded here. Figure 3 In the embodiment, the folds are represented by diagonal lines in the nonwoven fabric 18 produced from the multilayer fiber web 3. Figure 1 and Figure 2 As shown by the double arrow in , the laying carriage is always moved back and forth in the horizontal direction on a pre-adjusted laying width, here for example on a predetermined working width.

[0042] In this embodiment, the feed belt 2 is deflected around first and second deflecting rollers 4 and 5, and around the deflecting roller 6 of the upper carriage. A cover belt 7 can be arranged above the feed belt 2 and, in this figure, is guided around a deflecting roller 8, the deflecting roller 6 of the upper carriage, and a further deflecting roller 12. Both belts 2 and 7 can be designed as endless belts driven over at least one additional deflecting roller (not shown). Other structural variations in which the laying carriage cooperates with another belt rather than the feed belt 2 are also possible and known.

[0043] In this embodiment, the feed belt 2 and cover belt 7 do not run parallel to each other, but rather form an open, acute angle toward the carding device 17, into which the fiber web 3 is drawn and slightly compressed. The fiber web 3 is guided around the deflecting rollers 6 of the upper carriage, with the cover belt 7 being guided laterally away by the deflecting rollers 12. The fiber web 3 is transported in the opposite direction, guided around the deflecting rollers 6 of the upper carriage at a 180° angle and deposited on a matching belt 13 arranged parallel to and below the feed belt 2. The matching belt 13 and the feed belt 2 now jointly clamp or guide the fiber web 3 to the depositing gap 11, which is essentially defined by the distance between the two depositing rollers 9, 10 of the depositing carriage. The fiber web 3 leaves the depositing gap 11 and is deposited onto a discharge belt 15 arranged below it. The laying carriage is then moved in a horizontal reciprocating direction across the width of the delivery belt 15, onto which the fiber web 3 is placed and folded. It is then moved in the working direction 14 (direction of the arrow) toward the functional unit 19 (see FIG. Figure 3 ) Continue to convey the fiber web 3 or nonwoven fabric 18 on the output belt 15 ( Figure 3 ).

[0044] The feed belt 2, cover belt 7, and counter belt 13 can be designed as endless belts, wherein the cover belt 7 and counter belt 13 can be designed to be air-permeable to conduct away air carried along with them. Using a perforated conveyor belt is a valuable embodiment. Using a screen belt is a preferred embodiment.

[0045] The input belt 2 and the cover belt 7 have the same direction of travel for the fiber web 3 and often have the same speed. If the two conveyor belts 2, 7 are driven at slightly different speeds, the orientation of the fibers on the surface relative to the neutral fibers of the fiber strip will be affected to a certain extent.

[0046] Now Figure 3As shown, the nonwoven fabric 18 produced from the fiber web 3 by laying in the cross-lapper 1 is conveyed to a downstream functional unit 19, before which the introduction strip 16 is produced by means of the cross-lapper 1. Figure 1 、 Figure 2 The cross-lapping machine 1 implemented manufactures the introduction strip 16 by placing the individual layers of the fiber web 3 on top of each other. For this purpose, the laying width of the nonwoven fabric 18, ie the laying width of the laid fiber web 3, is determined by the predetermined working width ( Figure 2 This can be the first of the lead-in strips 16. Figure 3 The section shown in FIG is therefore the narrowest section of the introduction strip 16. Its width corresponds to the introduction width which is a fraction of the predetermined working width.

[0047] After a further layer of the fiber web 3 has been placed on the delivery belt 15, the laying width can be increased again from the introduction width until the predetermined working width is reached. Figure 2 As shown, a wedge or triangle is produced which is substantially increased in width by the introduction of the nonwoven fabric 18. Figure 3 As shown, the wedge shape is created by increasing the laying width from layer to layer. In this way, for example, the laying width of the fiber web 3 can be adjusted to an introduction width of 1000 mm in a first step and then increased by, for example, 30 mm to 500 mm from layer to layer of the fiber web 3. This results in a predetermined working width of, for example, 4500 mm after seven layers.

[0048] In principle, it is also possible to produce the introduction strip 16 not in a wedge or triangle shape, but in a rectangular shape, i.e., with a constant introduction width from layer to layer. By laying the introduction strip 16 with the aid of the crosslapper 1, significantly fewer defective nonwoven fabrics 18 are produced. For example, a full working width of 4500 mm can be achieved from an introduction strip 16 with a width of 500 mm using a single step.

[0049] exist Figure 4 FIG. 1 shows an alternative embodiment of transporting the nonwoven fabric 18 from the cross-lapper 1 to the downstream functional unit 19. Figure 1 、 Figure 2 The cross-lapping machine 1 implemented manufactures the introduction strip 16 by placing double layers of the fiber web 3 on top of each other. For this purpose, the laying width of the nonwoven fabric 18, ie the laying width of the laid fiber web 3, is determined by the predetermined working width ( Figure 2 This can be the first of the lead-in strips 16. Figure 4 The section shown in FIG is therefore the narrowest section of the introduction strip 16. Its width corresponds to the introduction width which is a fraction of the predetermined working width.

[0050] After placing two further layers of the fiber web 3 on the delivery belt 15, the laying width can be increased again from the introduction width until the predetermined working width is reached. Figure 2 As shown, a wedge or triangle is produced which is substantially increased in width by the introduction of the nonwoven fabric 18. Figure 4 As shown, the wedge shape is produced by increasing the laying width from two layers to two layers. In this way, for example, the laying width of the fiber web 3 can be adjusted to an introduction width of 1000 mm in a first step and then widened step by step, here from two layers to two layers of the fiber web 3, by, for example, 30 mm to 500 mm.

[0051] The present invention enables the transport of a fiber web 3 or nonwoven fabric 18 produced by a cross-lapper 1 to a functional unit 19 connected to the cross-lapper 1, such as a needle loom, water jet consolidation system, or thermobonding machine. After the introduction strip 16 is produced, the introduction strip is transferred to a downstream functional unit 19, and the introduction width is then increased to a predetermined working width. During the production of the introduction strip 16, the line speed of the nonwoven fabric 18 produced in the cross-lapper 1 must be reduced from the working line speed to the introduction line speed. This is achieved by controlling the entire system.

[0052] The cross-lapper 1 can be equipped with a controller 20, which is configured to carry out the method according to the present invention and preferably to operate the laying device to produce the introduction strip 16 so that the laying width is reduced by the cross-lapper from a predetermined working width to the introduction width. The controller 20 of the cross-lapper 1 is controlled by a higher-level controller of the entire system, since upstream bulk fiber feeders, carding devices 17, or opening stations must also be shut down and then restarted simultaneously at a certain speed. The same applies to downstream functional units 19. The linear speed of the delivery belt 15 can also be adjusted by means of the controller 20 so that during the production of the introduction strip 16, the linear speed is reduced from the working linear speed to the introduction linear speed, with the linear speed preferably increasing again from the introduction linear speed to the working linear speed with each additional layer of the fiber web 3.

[0053] Reference Signs List

[0054] 1 Crosslapper

[0055] 2 Input belts

[0056] 3 Fiber mesh

[0057] 4 First turning roller

[0058] 5 Second turning roller

[0059] 6 Steering roller of upper carriage

[0060] 7 Covering belt

[0061] 8 Steering roller

[0062] 9 laying rollers

[0063] 10 laying rollers

[0064] 11 Laying gap

[0065] 12 Steering rollers

[0066] 13. Matching belt

[0067] 14 Work Direction

[0068] 15 output belt

[0069] 16Introduction strip

[0070] 17 Carding equipment

[0071] 18 non-woven fabrics

[0072] 19 functional units

[0073] 20 controllers

Claims

1. A method for forming a nonwoven fabric (18) made of a multilayer fiber web (3) by means of a cross-lapper (1), wherein a plurality of layers made of a fiber web (3) are laid on top of one another by means of the cross-lapper in order to adjust a predetermined working width, wherein: By means of the cross-lapper (1), the laying width of the laid fiber web (3) is reduced from the predetermined working width to the introduction width in order to produce an introduction strip (16).

2. The method according to claim 1, characterized in that The introduction width corresponds to between 5% and 60% of the predetermined working width.

3. The method according to claim 1, characterized in that The predetermined working width is temporarily reduced to the lead-in width in order to produce the lead-in strip (16).

4. The method according to claim 2, characterized in that The predetermined working width is temporarily reduced to the lead-in width in order to produce the lead-in strip (16).

5. The method according to any one of claims 1 to 4, characterized in that The laying width increases with each additional layer of the fiber web (3) from the introduction width until the predetermined working width is reached.

6. The method according to claim 5, characterized in that The laying width increases by at least 30 mm from one layer to another.

7. The method according to any one of claims 1 to 4, characterized in that The laying width is gradually increased with each two layers of fiber web (3) or a multiple of two layers of fiber web (3) from the introduction width until the predetermined working width is reached.

8. The method according to claim 7, characterized in that The laying width increases by at least 30 mm per step.

9. The method according to any one of claims 1 to 4, 6 and 8, characterized in that When producing the introduction strip (16), the line speed of the nonwoven fabric (18) to be produced in the cross-lapper (1) is reduced from the working line speed to the introduction line speed, wherein the line speed increases from the introduction line speed to the working line speed with each additional layer of the fiber web (3).

10. The method according to claim 5, characterized in that When producing the introduction strip (16), the line speed of the nonwoven fabric (18) to be produced in the cross-lapper (1) is reduced from the working line speed to the introduction line speed, wherein the line speed increases from the introduction line speed to the working line speed with each additional layer of the fiber web (3).

11. The method according to claim 7, characterized in that When producing the introduction strip (16), the line speed of the nonwoven fabric (18) to be produced in the cross-lapper (1) is reduced from the working line speed to the introduction line speed, wherein the line speed increases from the introduction line speed to the working line speed with each additional layer of the fiber web (3).

12. A cross-lapping machine (1) for forming a nonwoven fabric (18) made of a multi-layer fiber web (3), wherein: The crosslapper (1) is designed such that it carries out the method according to one of the preceding claims.

13. The cross-lapper (1) according to claim 12, characterized in that The cross-lapper (1) comprises at least one belt for transporting the fiber web (3) from an input area of ​​the cross-lapper (1) to a laying device, wherein the laying device places the fiber web (3) on an output belt (15) and the laying device is movable back and forth along a predetermined working width in order to place one layer of the fiber web (3) on another layer, wherein a controller (20) is assigned to the cross-lapper (1) and is arranged so that it implements the method according to one of claims 1 to 11 and operates the laying device to produce the introduction strip (16) so that the laying width is reduced from the predetermined working width to the introduction width by means of the cross-lapper (1).

14. The cross-lapper (1) according to claim 13, characterized in that The laying device is configured as a laying carriage or a laying arm.

15. The cross-lapper (1) according to claim 13, characterized in that The linear speed of the output belt (15) can be adjusted by means of the controller (20) so that during the production of the introduction strip (16), the linear speed is reduced from the working linear speed to the introduction linear speed, wherein the linear speed is increased again from the introduction linear speed to the working linear speed with each additional layer of the fiber web (3).

16. The cross-lapper (1) according to claim 13, characterized in that The controller (20) of the cross-lapper (1) is controlled by the controller of the device for producing nonwoven fabrics in order to change the working speed.

17. Use of a cross-lapper (1) with the aid of which a nonwoven fabric (18) made of a multi-layer fiber web (3) can be formed by reducing the laying width of the laid fiber web (3) from a predetermined working width to an introduction width with the aid of the cross-lapper (1) in order to produce an introduction strip (16).

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