Apparatus and method for consolidating a fiber-containing layer to form a nonwoven web

Abstract

The invention relates to a device (100, 200, 300, 400) for consolidating a material layer (13) comprising short fibers and a material layer (5) comprising long fibers to form a nonwoven web (23). A pre-curing unit (22) is arranged immediately after a transition point #imgabs0# along a production direction (P), the pre-curing unit having two compacting mechanisms (10, 10') spaced apart from each other along the production direction (P) and a consolidating mechanism (34) arranged between the compacting mechanisms (10, 10') along the production direction. The compacting mechanisms (10, 10') and the consolidating mechanism (34) are integrated into the device in such a way that the compacting mechanisms and the consolidating mechanisms are always in a common operating state.

Description

Technical Field

[0001] The invention relates to a device for consolidating a layer of short fibers and a layer of long fibers to form a nonwoven web, the device having a first endless belt on which the layer of long fibers can be laid and displaced in the production direction, and a second endless belt by means of which the layer of short fibers can be transferred to the layer of long fibers at a transfer point. The invention also relates to a method for producing a nonwoven web having a layer of short fibers and long fibers. Background Art

[0002] Such an apparatus and such a method are known from EP 3 283 679 B1. At the transition point, due to the action of the deflection rollers, the two material layers are pre-compacted before they reach the region between the first belt and the second belt during the feed in the production direction, but in this region the two conveyor belts have a distance greater than the sum of the thicknesses of the two material layers. Therefore, no compaction occurs in this region.

[0003] In practice it has been shown that when producing nonwoven webs comprising two layers comprising short fibers with an average fiber length of typically less than 1 mm to a maximum of 10 mm and long fibers with a length of typically between 10 mm and 150 mm, the production results are not always reproducible. Summary of the invention

[0004] The object of the present invention is therefore to provide a device and a method by means of which the reproducibility of the manufacturing results is improved. In particular, the device and the method should be suitable for the production of nonwoven webs for which a layer of light short fibers (e.g. with a weight per unit area of ​​10 to 50 grams per square meter), for example a light and wetted wood fiber layer, is applied to a layer of long fibers (e.g., which may have a weight per unit area of ​​15 to 50 grams per square meter) and is bonded to the layer. Such production usually presents difficulties, since the carded layer of long fibers usually has elastic properties and exhibits a recovery effect after compaction, which may produce deformations, defects or even cracks in the wood fiber layer. The nonwoven web produced may, for example, have a weight per unit area of ​​20 to 150 grams per square meter, preferably 40 to 70 grams per square meter.

[0005] This object is achieved by the device specified in claim 1 and the method specified in claim 15. Advantageous developments are the subject matter of the dependent claims.

[0006] The device according to the invention comprises a pre-curing unit arranged immediately after the transition point in the production direction. "Immediately after" is to be understood as meaning that no other means are arranged between the transition point and the pre-curing unit, which lead to compaction and / or curing of the two layers. The term "pre-curing unit" is to indicate that the components belonging to this unit have a functionally inseparable relationship.

[0007] The pre-curing unit has two compacting mechanisms spaced apart from each other in the production direction. With these compacting mechanisms, in one area, the distance between the second belt and the first belt, which preferably extends parallel thereto, can be reduced to a value that is less than the sum of the thicknesses of the two material layers, whereby the two material layers can be compacted due to the pressure acting on them in a planar manner in this area. The two belts can also touch in this area, in other words, the distance takes the value zero when no material layer passes through the pre-curing unit. When one or more material layers pass / go by, due to the flexibility of at least one of the belts, the belts (i.e. the first belt and the second belt) can again maintain a certain distance in this area, without the pre-curing unit having to be displaced for this purpose.

[0008] The two compacting mechanisms may either both act on the same first belt and second belt; or one of the two compacting mechanisms may act on one belt, while the other of the two compacting mechanisms may act on the other belt.

[0009] The pre-curing unit further comprises a curing device, in particular a hydroentanglement curing device, arranged between the compacting devices, by means of which the two material layers can be cured to one another by entanglement of the fibers. The curing device is preferably designed such that the entanglement of the fibers is not effected approximately over the entire area in which the compaction also takes place, but only in partial areas, in particular linearly, by means of a nozzle beam extending transversely to the production direction.

[0010] Furthermore, according to the invention, the compacting device and the solidifying device are integrated into the device in such a way that they are always jointly in operation when the material layer comprising short fibers is transferred via the second endless belt.

[0011] Since the solidification means are arranged between the compacting means and solidification is carried out simultaneously by compaction in connection therewith, recovery of the material layer comprising long fibers is avoided, so that the risk of structural defects in the nonwoven web having two material layers is significantly reduced by using the device according to the invention or by using the method according to the invention.

[0012] A first preferred embodiment of the device according to the invention comprises a pre-curing unit, wherein the compacting means each comprise a pressure roller.

[0013] However, it has been found that the manufacturing outlay of the device according to the invention can be reduced without restricting its functionality if the compacting means of the pre-curing units each comprise a pressure beam, as in the second embodiment.

[0014] The compacting means of the pre-curing unit can be arranged such that in an operating state it bears against the first belt and is preferably displaced in parallel in the region in which the pre-curing unit is active towards the second belt.

[0015] However, an embodiment of the device according to the invention is preferred in which the pre-curing unit is designed such that the compacting device rests on the second belt and is preferably displaced parallel to the first belt. The compacting device is then arranged inside the second endless belt.

[0016] If the first compacting means in the production direction is a pressure roller, the guiding of the second belt is preferably selected such that the distance from the line extending transversely to the production direction, along which the second belt first touches the outer circumference of the pressure roller, to the upper side of the first belt corresponds at least to the thickness of the fiber layer. Typically, this distance is 15 mm, 20 mm or more. Due to this design, undesired compaction of the material layer before the transition point is avoided.

[0017] In a particularly preferred embodiment, a lower roller, which is surrounded by the second belt, is arranged in front of the pre-curing unit as viewed in the production direction and / or behind the pre-curing unit as viewed in the production direction. Due to this measure, an improved guidance of the second belt is achieved, which can improve the pre-curing process that can be achieved with the device according to the invention.

[0018] Particularly preferred is an embodiment in which the lower roller is arranged such that the second belt has an entry angle α between 1° and 10° and an exit angle α' of greater than 1° relative to the first belt between the lower roller and the compacting device adjacent thereto. It has been shown that particularly good results can be achieved with the pre-curing unit at entry angles in this range, but the size of the exit angle is of only minor significance for the results.

[0019] In another particularly preferred embodiment, the first compacting device acts from above on the lower run of the second endless belt, as viewed in the production direction, and the second compacting device acts from below on the upper run of the first endless belt, as viewed in the production direction, in such a way that the first endless belt undergoes a change of direction when passing / walking past the second compacting device. It has surprisingly been found that this reduces the undesirable tendency of the pre-cured material layer to adhere to the second endless belt. The change of direction is preferably at least 1°.

[0020] In a preferred embodiment, the first compacting mechanism comprises a first lower pressing roller.

[0021] In a particularly preferred embodiment, the second compacting device comprises a suction chamber which can be acted upon by negative pressure. This can again significantly reduce the tendency of the pre-cured material layer to adhere to the second circulating belt.

[0022] The suction chamber then preferably comprises at least one contact surface for the first endless belt and further preferably comprises a suction opening.

[0023] In a further preferred embodiment, the second compacting device comprises a pressure roller which can be designed in the same way as the first, lower pressure roller.

[0024] In this case, preferably a suction chamber is arranged along the production direction, preferably immediately behind the pressure roller. Alternatively, the pressure roller is configured as a suction roller, by means of which an air flow through the first circulating belt can be generated.

[0025] The hydroentanglement device is preferably designed as a nozzle beam, which outputs water jets with a diameter of typically between 80 and 180 micrometers. For this purpose, the water jet beam is attached to a pressure source, by means of which water can be introduced at a pressure of up to 100 bar, but usually significantly lower than this pressure, for example a maximum of 30 bar or lower, depending on the requirements for the pre-curing effect based on the properties of the short and long fibers.

[0026] The nozzle beam is preferably arranged within the second belt, particularly preferably together with the two compacting devices and particularly preferably at the same distance from the two compacting devices as viewed in the production direction.

[0027] In the method according to the invention for producing a nonwoven web, a layer comprising short fibers is applied to a layer comprising long fibers and the two layers are subsequently compacted by means of a mechanical pressure acting over a certain length range of the two layers. In addition, the two layers are mutually solidified by means of water jets, which act over a part of the length range. It has been shown that this measure achieves particularly effective pre-solidification of the two layers without the loosening of the short fibers occurring to an especially undesirable extent.

[0028] Particularly preferably, the water jet is directed toward the material layer comprising short fibers. It has been shown that, due to this measure, pre-curing is particularly effective and at the same time the water can be easily collected under the effect of negative pressure by means of a suction box and directed back to the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with the aid of purely schematic drawings.

[0030] Figure 1 A first embodiment of the device according to the invention is shown;

[0031] Figure 1a Show Figure 1 Details;

[0032] Figure 2 A second embodiment of the device according to the invention is shown;

[0033] Figure 3 A third embodiment of the device according to the invention is shown;

[0034] Figure 4 Show Figure 3 A magnified view of the local IV in;

[0035] Figure 5 A fourth embodiment of the device according to the invention is shown;

[0036] Figure 6 The first pre-curing unit ( Figure 5 Partial illustration of the local VI);

[0037] Figure 7 The second pre-curing unit corresponds to Figure 6 Partial diagram of

[0038] Figure 8 The third pre-curing unit corresponds to Figure 6 a partial illustration of

[0039] Fig. 9 The first pre-curing unit corresponds to Figure 6 , in which the guidance of the upper run of the first endless belt is changed. DETAILED DESCRIPTION

[0040] The device according to the invention (device 100) is Figure 1 A first embodiment, denoted as a whole by 100, comprises a combing unit 1, with which a layer of long fibers can be produced. The combing unit comprises a circulating deposit belt 2 having an upper run 3, on which the long fibers can be deposited in the form of a layer 5 comprising long fibers 4.

[0041] The device 100 also includes a suction roller 6, by means of which the material layer 5 can be transferred to the upper return section 7 of the first belt 8 circulating around the roller 9 in the clockwise direction. Figure 1 The movement is in the direction of the arrow marked in, which therefore represents the production direction P.

[0042] The first endless belt 8 is designed to be liquid-permeable and gas-permeable, for example as a screen belt.

[0043] The device 100 further comprises a device 11 for providing a layer 13 containing staple fibers 12. The device 11 comprises for this purpose a second endless belt 14 which circulates around a roller 15 in a counterclockwise direction.

[0044] The second endless belt 14 is again designed to be liquid-permeable and air-permeable, for example as a screen belt. Due to the arrangement of the rollers 15, it forms a rising region 16 viewed in the circulating direction, in which the short fibers 12 (for example as an aqueous emulsion) are deposited from an applicator 17 to form the material layer 13.

[0045] The material layer 13 including the staple fibers 12 passes through the regions 18 , 19 , which descend obliquely with respect to the circulating direction, to the lower run 20 of the second endless belt 14 . The lower run 20 is formed between two lower rollers 21 .

[0046] In the device 100, the lower rollers 21, 21' form compacting means 10, 10' and are part of the pre-curing unit 22. When the device 100 is in operation, these compacting means are located relative to the upper run 7 of the first endless belt 8 in such a position that the distance between the lower run 20 of the second endless belt 14 and the upper run 7 of the first endless belt 8 is less than the sum of the thicknesses of the material layer 5 and the material layer 13.

[0047] As in Figure 1a As shown in , at least the first roller 21 in the production direction has a diameter D. This diameter is greater than or equal to one twentieth of the length of the roller transverse to the production direction. The guidance of the second belt is selected so that the line extending transverse to the production direction (along which the second belt first touches the outer circumference of the roller 21) has a distance A that corresponds at least to the sum of the thicknesses of the layers 13 and 5.

[0048] The transfer of the material layer 13 to the material layer 5 occurs due to the arrangement of the roller 15 and the lower roller 21 at the transition point ü, which is located in front of the lower roller 21 shown on the left in the figure when viewed in the production direction P. Since the distance between the upper run 7 and the lower run 20 is less than the sum of the thicknesses of the two material layers 5 and 13, the two material layers undergo a first flat compaction on the way to forming a flowing web (Flieβbahn, continuous / flowing nonwoven) 23 when passing through the area between the two lower rollers 21. The size of the surface here depends on the distance of the two lower rollers 21 in the production direction P.

[0049] In order to be able to achieve the desired compaction, the first belt 8 and the second belt 14 must circulate at the same speed so that no friction occurs during the compaction, which could negatively influence the compaction process.

[0050] In order to make the two layers 5, 13 have sufficient strength after leaving the area between the upper run 7 and the lower run 20 for other subsequent processing steps to form a flowing web, the solidification unit 22 includes a nozzle bar 24 arranged between the two lower rollers 21 along the production direction P and arranged inside the second endless belt 14, and a collecting device 25, the nozzle bar 24 forming a solidification mechanism 34, and the collecting device 25 is arranged at a corresponding position along the production direction and arranged inside the first endless belt 8, and the collecting device 25 can be a suction box loaded with negative pressure. The nozzle bar 24 includes a plurality of nozzles on its side facing the lower run 20, during the operation of the device 1, water jets flow out of the nozzles under pressure and penetrate the lower run 20 of the second endless belt 14, solidifying the two layers 5 and 13 by fiber entanglement. The collecting device 25 is used to collect at least part of the water discharged from the nozzle bar 24, which can then (after treatment if necessary) be transported back to the production process.

[0051] For further solidification and compaction, a plurality of nozzle beams 26 and a plurality of collecting devices 27 are arranged outside the second endless belt in order to additionally solidify the layers 5 and 13 from above.

[0052] A further curing device 28 is arranged downstream in the production direction P. The further curing device comprises two curing rollers 29, which are surrounded by the material layers 5 and 13 in operation so that each of the two material layers rests on one of the two curing rollers over an angular range of approximately 120°. Two further nozzle beams 30 are provided for each curing roller 29, which act in the region where the material layers 5, 13 rest on the suction cylinders 29.

[0053] The curing drums each have air-permeable and liquid-permeable lateral surfaces, so that at least part of the water discharged by the nozzle beam 30 during operation can be sucked away by the curing drums and can also be fed back to the production process (if necessary after treatment). The curing device 28 serves to further cure the two layers 5 and 13 to form a nonwoven web 23, which, after passing through the curing device, can be fed to other processing steps not described here.

[0054] Figure 2 A second embodiment of the device according to the invention (device 200) is shown. Only the differences from device 100 are described below. To avoid repetitions, reference is made to the explanations for device 100, which also apply to device 200, in other respects.

[0055] Instead of the lower rollers 21, the device 200 comprises lower rollers 31 which are at a greater distance from each other in the production direction P and also from the upper run 7 of the first endless belt 8 than the aforementioned lower rollers 21. The lower rollers 31 are not a component of the pre-curing unit 22. The lower rollers are formed in the device 200 by two pressure beams 32 arranged parallel to each other and perpendicular to the production direction P, which are arranged in the device 100 corresponding to the lower rollers 21 and replace their function in the pre-curing unit 22.

[0056] The pressure beam 32 may be provided with a plastic cover or a ceramic coating in the region where it contacts the endless belt 14 , in order to reduce the friction with the endless belt 14 .

[0057] Since the lower roller 31 is arranged at a greater distance from the upper run 7, the second endless belt 14 extends between the deflection roller 31 and the corresponding pressure beam, while forming an angle α, α', which can be between 1° and 10°, as in Figure 4 Combination Figure 3 As described in the third embodiment of the device according to the present invention (device 300) shown in FIG.

[0058] Only the differences between the device 300 and the device 200 are described below. In this respect, in order to avoid repetitions, reference is made to the explanations regarding the device 200 and also regarding the device 100.

[0059] In the device 300, the two pressure bars 32 are replaced by pressure rollers 33. This design is recommended in particular when a higher pressure is to be applied for compaction by means of the pre-curing unit 22, since this would lead to an undesirable increase in friction between the pressure bars 32 and the second endless belt 14 in the device 200.

[0060] As reference Figure 1 As in the first embodiment 100 of the device according to the invention explained above, the device according to the invention (device 400) is Figure 5 A fourth embodiment, which is designated as a whole by 400, comprises a combing unit 1 with which a layer of long fibers can be produced. The combing unit comprises a circulating deposit belt 2 with an upper run 3, on which the long fibers can be deposited in the form of a layer 5 comprising long fibers 4.

[0061] The device 400 also includes a suction roller 6, by means of which the material layer 5 can be transferred to the upper run 7 of the first belt 8 circulating around the roller 9 in the clockwise direction. Figure 1 The movement is in the direction of the arrow marked in, which therefore represents the production direction P.

[0062] The first endless belt 8 is designed to be liquid-permeable and gas-permeable, for example as a screen belt.

[0063] The device 400 further comprises means 11 for providing a layer 13 comprising staple fibres 12. The means 11 comprises for this purpose a second endless belt 14 which circulates around a roller 15 in a counterclockwise direction.

[0064] The second endless belt 14 is again designed to be liquid-permeable and air-permeable, for example as a screen belt. Due to the arrangement of the rollers 15, it forms an ascending region 16 viewed in the direction of circulation, in which the short fibers 12 (for example as an aqueous emulsion) are deposited from an applicator 17 to form the material layer 13.

[0065] The material layer 13 including the short fibers 12 passes through the regions 18, 19 and reaches the lower run 20 of the second endless belt 14, which descends obliquely with respect to the circulating direction. The lower run 20 is formed between a first lower press roller 35 along the production direction and a second lower press roller 36 along the production direction.

[0066] In the device 400, the first lower pressure roller 35 forms the first compacting mechanism 10 and is part of the pre-curing unit 22. In operation of the device 400, the first lower pressure roller 35 is located relative to the upper run 7 of the first endless belt 8 in a position in which the distance between the lower run 20 of the second endless belt 14 and the upper run 7 of the first endless belt 8 is less than the sum of the thicknesses of the material layer 5 and the material layer 13.

[0067] The second compacting device 10', which is also part of the pre-curing unit 22, forms a suction chamber 37. The second compacting device extends parallel to the first lower pressure roller 35 approximately at least over the width of the first endless belt 8. The suction chamber 37 has an upper, flat contact surface 38, on which the upper run 7 of the first endless belt 8 rests with its lower side. Between the contact surfaces 38, the suction chamber 37 has one or more suction openings 39. The suction chamber 37 is arranged so that the first endless belt 8 is pressed upward by the suction chamber, so that the upper run 7 between the first lower pressure roller 35 and the suction chamber 37 extends parallel to the lower run 20 of the second endless belt 14. Therefore, in the device 400, the pre-curing unit 22 extends between the first lower pressure roller 35 and the suction chamber 37.

[0068] Viewed in the production direction behind the suction chamber 37, the first endless belt 8 descends at an angle β relative to the lower run 20 of the second endless belt 14. Thus, before the second endless belt 14 turns upward around the second lower roller 36, the distance between the belt 8 and the belt 14 increases in the production direction behind the suction chamber.

[0069] This first embodiment of the pre-curing unit 22 is Figure 6 are shown separately in .

[0070] The material layer 13 is transferred to the material layer 5 due to the arrangement of the rollers 15 and the first lower pressure roller 35 at the transition point ü, which is located upstream of the lower pressure roller 35 as viewed in the production direction P. Since the distance between the upper run 7 and the lower run 20 between the compacting elements 10 is less than the sum of the thicknesses of the two material layers 5 and 13, the two material layers undergo a first flat compaction on the way to forming the flowing web 23 when passing through the area between the first lower pressure roller 35 and the suction chamber 37. The size of the surface here depends on the distance between the first lower pressure roller 35 and the suction chamber 37 in the production direction P.

[0071] In order to be able to achieve the desired compaction, the first belt 8 and the second belt 14 must circulate at the same speed so that no friction occurs during the compaction, which could negatively influence the compaction process.

[0072] Tests have surprisingly shown that the risk of the material layer 13 undesirably adhering to the second endless belt 14 behind the pre-curing unit 22 is reduced if the pre-curing unit 22 is bounded in the production direction by two compacting devices 10, 10', wherein the first compacting device 10 acts on the second endless belt 14 and the second compacting device 10' acts on the first endless belt 8 in such a way that the first endless belt 8 undergoes a change of direction of an angle β of at least 1° when passing the other compacting device 10'. In the device 400, the risk of adhesion is further reduced by configuring the second compacting device 10' as a suction chamber 37, at which a negative pressure is applied during operation of the device 400, thereby generating an air flow through the first endless belt 8, which supports the separation of the material layer 13 from the second endless belt 14.

[0073] In order to make the two layers 5, 13 have sufficient strength after leaving the area between the upper run 7 and the lower run 20 for other subsequent processing steps to form a flowing web, the pre-curing unit 22 includes a nozzle bar 24 arranged between the first lower pressure roller 35 and the second lower pressure roller 36 along the production direction P and inside the second endless belt 14, and a collecting device 25 arranged at a corresponding position along the production direction and arranged inside the first endless belt 8, which can be a suction box loaded with negative pressure. The nozzle bar 24 includes a plurality of nozzles on its side facing the lower run 20, and during the operation of the device 1, water jets flow out of the nozzles under pressure and penetrate the lower run 20 of the second endless belt 14, curing the two layers 5 and 13 by the entanglement of the fibers. The collecting device 25 is used to collect at least part of the water discharged from the nozzle bar 24, which can then (after treatment if necessary) be transported back to the production process.

[0074] For further solidification and compaction, a plurality of nozzle beams 26 and a plurality of collecting devices 27 are arranged outside the second endless belt in order to additionally solidify the layers 5 and 13 from above.

[0075] A further curing device 28 is arranged downstream in the production direction P. The further curing device comprises two curing rollers 29, which are surrounded by the material layer 5 and the material layer 13 in such a way that each of the two material layers bears against one of the two curing rollers over an angular range of approximately 120°. Two further nozzle beams 30 are provided for each curing roller 29, which act in the region where the material layers 5, 13 bear against the suction cylinder 29.

[0076] The curing drums each have air-permeable and liquid-permeable lateral surfaces, so that at least part of the water discharged by the nozzle beam 30 during operation can be sucked away by the curing drums and can also be fed back to the production process (if necessary after treatment). The curing device 28 serves to further cure the two layers 5 and 13 to form a nonwoven web 23, which, after passing through the curing device, can be fed to other processing steps not described here.

[0077] The second embodiment of the pre-curing unit 22 of the fourth embodiment of the apparatus 400 is Figure 7 In order to avoid repetition, only the differences from the first embodiment of the pre-curing unit are to be described. The same reference numerals denote the same components.

[0078] In a second embodiment of the pre-curing unit 22, a pressure roller 40 is provided instead of the suction chamber 37, which is oriented parallel to the first lower roller, extends over the entire width of the first circulating belt 8 and presses against the upper return section 7 of the first circulating belt from below, which is similar to the suction chamber 37 in the first embodiment of the pre-curing unit 22.

[0079] In this second embodiment, therefore, the separation of the material layer 13 from the second endless belt 14 in the production direction behind the pressure roller 40 is only supported by the change of direction experienced by the first endless belt 8 when passing the roller 40. If necessary, the roller 20 can be designed as a suction roller that can be loaded with negative pressure in order to generate an air flow through the surface of the first belt 8 directed toward the suction roller.

[0080] The third embodiment of the pre-curing unit 22 of the fourth embodiment of the apparatus 400 is Figure 8 In order to avoid repetition, only the differences from the second embodiment of the pre-curing unit are described. The same reference numerals denote the same components.

[0081] In the third embodiment of the pre-curing unit 22, a pressure roller 40 is provided, which is oriented parallel to the first lower pressure roller 35, extends over the entire width of the first endless belt 8 and presses against the upper run 7 of the first endless belt from below. In the production direction, a suction chamber 41 is arranged immediately after the pressure roller 40, which, although not resting against the upper run 7 of the first endless belt 8 from below, generates an air flow directed from top to bottom through the belt 8 by applying negative pressure and thus assists in separating the support material layer 13 from the upper endless belt 14. For this purpose, the suction chamber 41 has a suction opening 42, which is adjacent to the pressure roller 40 when viewed in the production direction.

[0082] In this third embodiment, therefore, the separation of the material layer 13 from the second endless belt 14 in the production direction behind the pressure roller 40 is not only caused by the change of direction that the first endless belt 8 undergoes when passing the pressure roller 40, but is also supported by the suction chamber 41. Since the first endless belt 8 is not supported by the suction chamber 41 for this purpose, but by the pressure roller 40 that rotates with it, and the first endless belt only rests on the suction chamber in such a way that the air flow caused by the suction chamber passes through the first endless belt 8, the friction acting on the first endless belt is reduced compared to the first embodiment of the precuring unit.

[0083] exist Fig. 9 4 shows a first embodiment of the pre-curing unit 22 of a fourth embodiment of the apparatus 400, wherein the guidance of the upper run 7 of the first endless belt is changed. In order to avoid repetition, only the first embodiment related to the pre-curing unit 22 is described. Figure 6The same reference numerals denote the same components.

[0084] For Figure 6 As for the guidance of the upper run 7 of the first endless belt 8 shown, the belt 8 does not undergo a change of direction when passing the first lower pressure roller 35. In order to increase the compaction effect of the first lower pressure roller 35, on the contrary Fig. 9 In the guiding method shown in FIG, the belt 8 is guided in such a way that the upper run 7 of the first endless belt 8 is pressed against the second endless belt 14 in the region of the first lower pressure roller 35 and thus undergoes a change of direction of a small angle λ due to the action of the pressure roller 35 .

[0085] The above three embodiments of the device according to the invention show a combing unit 1 for providing a layer 5 comprising long fibers 4. It goes without saying that not only a combing unit can be used to provide such a layer, but also other devices by which a layer comprising long fibers 4 is produced online can be used to provide such a layer. In addition, the layer can also be produced separately, that is to say offline, and provided, for example, in the form of a wound roll. In this case, for example, an unwinding station is provided instead of a combing unit.

[0086] Reference numerals list

[0087] 100, 200, 300, 400 devices

[0088] 1 Carding unit

[0089] 2 Laying belt

[0090] 3 Return section

[0091] 4 Long Fiber

[0092] 5 Material layer

[0093] 6 suction rollers

[0094] 7 Upper return section

[0095] 8 First loop belt

[0096] 9 Rollers

[0097] 10, 10' compaction mechanism

[0098] 11 Institutions

[0099] 12 Short Fiber

[0100] 13 Material layer

[0101] 14 Second loop

[0102] 15 Roller

[0103] 16 Regions

[0104] 17 Applicator

[0105] 18 Regions

[0106] 19 Regions

[0107] 20 Lower return section

[0108] 21, 21' lower roller

[0109] 22 Pre-curing unit

[0110] 23 Flowing web

[0111] 24 Nozzle beam

[0112] 25 Collection device

[0113] 26 Nozzle beam

[0114] 27 Collection device

[0115] 28 Curing mechanism

[0116] 29 Curing roller

[0117] 30 Nozzle beam

[0118] 31 Lower roller

[0119] 32 Pressure beam

[0120] 33 Press Roller

[0121] 34 Curing mechanism

[0122] 35 First lower pressure roller

[0123] 36 Second lower pressure roller

[0124] 37 Suction Chamber

[0125] 38 contact surface

[0126] 39 Suction opening

[0127] 40 Pressure Roller

[0128] 41 Suction chamber

[0129] 42 Suction opening

[0130] α Angle

[0131] β angle

[0132] λ Angle

[0133] P Production direction

[0134] Transfer part

Claims

1. An apparatus (100, 200, 300, 400) for consolidating a layer (13) comprising short fibers (12) and a layer (5) comprising long fibers (4) to form a nonwoven web (23), comprising: a first endless belt (8) on which the layer (5) comprising long fibers (4) can be laid and displaced along a production direction (P), and a second endless belt (14), by means of which the material layer (13) comprising short fibers (12) can be transferred at a transfer point (Ü) to the material layer (5) comprising long fibers (4), It is characterized in that The device (100, 200, 300, 400) comprises a pre-curing unit (22) arranged immediately after the transition point (Ü) along the production direction (P), the pre-curing unit having two compacting devices (10, 10') spaced apart from one another along the production direction (P), the compacting devices acting on the first circulating belt (8) or the second circulating belt (14) in one area, The invention also comprises a solidification device (34) arranged between the two compacting devices (10, 10') along the production direction (P), by means of which the two material layers (5, 13) can be solidified with each other through the entanglement of the long fibers and the short fibers (5, 12). The compacting device (10, 10') and the solidifying device (34) are integrated into the device (100, 200, 300, 400) in such a way that when the material layer (13) comprising short fibers (12) is transferred by means of the second circulating belt (14), the compacting device and the solidifying device are always in a common operating state.

2. The device according to claim 1, characterized in that The compacting mechanisms (10, 10') each comprise a pressing roller (33).

3. The device according to claim 1, characterized in that The compacting mechanisms (10, 10') each comprise a compacting beam (32).

4. The device according to claim 1, characterized in that The compacting device (10, 10') is arranged such that, in an operating state, it abuts against the first circulating belt (8) or against the second circulating belt (14).

5. The device according to any one of claims 1 to 4, characterized in that A lower roller (31) surrounded by the second circulating belt (14) is arranged before the pre-curing unit (22) as viewed along the production direction (P), and / or a lower roller (31) surrounded by the second circulating belt (14) is arranged after the pre-curing unit (22) as viewed along the production direction (P).

6. The device according to claim 5, characterized in that The lower roller (31) is arranged so that the second endless belt (14) has an entry angle (α) between 1° and 10° and an exit angle (α') greater than 1° between the lower roller (31) and the corresponding adjacent compacting mechanism (10) relative to the first endless belt (8).

7. The device according to claim 1, characterized in that When viewed along the production direction (P), the first compacting mechanism (10) acts from above on the lower return section (20) of the second circulating belt (14), and when viewed along the production direction (P), the second compacting mechanism (10') acts from below on the upper return section (7) of the first circulating belt (8), in such a way that the first circulating belt (8) undergoes a change in direction of a certain angle (β) when passing through the second compacting mechanism (10').

8. The device according to claim 7, characterized in that The first compacting mechanism (10) comprises a first lower pressing roller (35).

9. The device according to claim 7 or 8, characterized in that The second compacting mechanism (10') comprises a suction chamber (37).

10. The device according to claim 9, characterized in that The suction chamber (37) comprises at least one contact surface (38) for the first endless belt (8) and comprises a suction opening (39).

11. The device according to claim 7 or 8, characterized in that The second compacting mechanism (10') comprises a pressure roller (40).

12. The device according to claim 11, characterized in that A suction chamber (41) is arranged immediately behind the pressure roller (40) in the production direction (P).

13. The device according to any one of claims 1 to 4, characterized in that The curing mechanism (34) comprises a nozzle beam (24).

14. The device according to claim 13, characterized in that The nozzle beam is arranged within the second circulating belt (14).

15. A method for producing a nonwoven web (23), the method comprising consolidating a layer (13) comprising short fibers (12) and a layer (5) comprising long fibers (4) to form a nonwoven web (23) by means of an apparatus according to any one of claims 1 to 14, wherein: A layer (13) comprising short fibers (12) is applied to a layer (5) comprising long fibers (4), and the two layers are subsequently compacted by means of a mechanical pressure acting over a length range of the two layers, and the two layers are solidified to each other by means of a water jet acting over a part of the length range.

16. The method according to claim 15, characterized in that The water jet is directed toward the layer (13) comprising short fibers (12).

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