Swiveling sieve belt device

Abstract

Nonwoven fabric production device with at least two meltblown nozzle devices (1, 2) - in particular with at least two meltblown nozzle beams - for producing meltblown fibers (3, 4), wherein a screen belt device (5) or a screen belt table is provided, which has at least one continuously circulating screen belt (6, 7), wherein the meltblown fibers (3, 4) of the meltblown nozzle devices (1, 2) can be deposited on the at least one screen belt (6, 7) of this screen belt device (5), wherein the meltblown nozzle devices (1, 2) define a vertical distance A1 or A2 between a respective nozzle tip (8, 9) and a surface of the at least one screen belt (6, 7) in a side view, wherein the sieve belt device (5) or a surface of the at least one sieve belt (6, 7) facing the meltblown nozzle devices (1, 2) is oriented or orientable obliquely in a side view with respect to a horizontal H for the purpose of changing the distance A1 and / or A2, wherein the sieve belt device (5) or the sieve belt table is pivotable for the inclined orientation or for changing the distance A1 and / or A2 about a pivot axis (10). and wherein the pivot axis (10) is arranged in the middle third, preferably in the middle or substantially in the middle of the sieve belt assembly (5) with respect to the longitudinal extent of the sieve belt assembly (5).

Description

[0001] The invention relates to a nonwoven fabric production device with at least two meltblown nozzle devices – in particular with at least two meltblown nozzle beams – for producing meltblown fibers, wherein a screen belt device or a screen belt table is provided which has at least one continuously circulating screen belt, wherein the meltblown fibers of the meltblown nozzle devices can be deposited on the at least one screen belt of this screen belt device, wherein the meltblown nozzle devices define a vertical distance A1 or A2 between a respective nozzle tip and a surface of the at least one screen belt in a side view.

[0002] Such nonwoven fabric production devices are generally known from practical experience and the prior art. DE 199 13 162 C1 describes a device for producing a nonwoven web from polymer filaments. WO 2006 / 049664 A1 relates to a plant for producing nonwovens. These can be meltblown nonwovens. WO 2015 / 176983 A1 describes a device for the random deposition of extruded plastic fibers. Critical process parameters are the distances A1 and A2, which often differ from each other and therefore must be individually adjusted depending on the nonwoven fabric being produced. In the known nonwoven fabric production devices, the respective adjustment of the distances A1 and A2 was achieved by varying the height of the meltblown die devices or meltblown die bars.This is due to the fact that the sieve belt forms a common reference plane for both meltblown nozzle devices, so that a height variation of the sieve belt varies the distances A1 and A2 equally, and individual adjustment of the distances A1 and A2 by varying the height of the sieve belt is not possible.

[0003] However, varying the height of the meltblown nozzle devices is very complex. Therefore, the invention aims to reduce the effort required to change the distances A1 and A2.

[0004] The aforementioned problem is solved by a nonwoven fabric production device according to claim 1. Advantageous further developments of the invention are the subject of the dependent claims.

[0005] The invention is based on the initial understanding that nonwoven fabric production equipment will require even greater flexibility in the future. These increased demands for flexibility make the conventional methods of varying the distances A1 and A2 by adjusting the height of the meltblown nozzles increasingly unattractive. The invention is further based on the understanding that tilting at least one of the screen belts provides an additional degree of freedom for adjusting the screen belt, thus enabling individual adjustment of the distances A1 and A2. The invention therefore pursues a radical new approach, eliminating the previously very complex height adjustment of the meltblown nozzles. As a result, the aforementioned problem is solved. According to the invention, the screen belt assembly or screen belt table is designed for tilting or...The device is pivotable for changing the distance A1 and / or A2 about at least one pivot axis, in particular about one or only one pivot axis. The term "pivotable" refers in particular to a device or pivoting mechanism on the screen belt assembly specifically designed for the purpose of pivoting.

[0006] It is highly preferred that the screen belt assembly has a pivoting device. The pivoting device can, in particular, have one or more rollers, a pivot axis, or a pivot shaft. The pivoting device preferably comprises at least one actuator, more preferably at least two, and particularly preferably at least four actuators. The actuator or actuators may be, for example, pneumatic, hydraulic, or electromechanical cylinders. However, entirely different drives are also conceivable, including, for example, electric motors with a spindle drive. It is highly preferred that at least one actuator is provided on each side of the pivot axis. It is advantageous if, in a top view and with respect to the machine direction, at least one actuator, and preferably two actuators, are arranged on each side of the screen belt assembly.It is particularly preferred if two pairs of actuators are provided on each side of the pivot axis, with each pair preferably having one actuator to the left of the screen belt and one actuator to the right of the screen belt in relation to the machine direction. The pivoting device may include springs, for example coil springs, to support the actuators.

[0007] It is particularly preferred that a lifting movement and / or a pivoting movement of the screen belt assembly can be performed to change the distance A1 and / or A2. It is particularly preferred that both a lifting movement and a pivoting movement of the screen belt assembly can be performed for varying degrees of change in the distances A1 and A2. If both pivoting and lifting movements are possible, two degrees of freedom are simultaneously available, which—particularly within a certain range of possible changes in height position—allow for any combination of distances A1 and A2.

[0008] It is highly preferred that the pivot axis is arranged perpendicular or substantially perpendicular to the machine direction (MD) or to the longitudinal extent of the screen belt assembly or the at least one screen belt in a top view. It is advantageous if the screen belt assembly comprises two side walls. The side walls are advantageously arranged on the left and right sides, respectively, of the screen belt assembly with respect to the machine direction. Advantageously, the screen belt assembly comprises at least two, and more preferably at least four, six, or eight screen belt rollers. It is preferred that the side walls support the screen belt rollers. It is preferred that the screen belt rollers guide or drive the at least one screen belt. The screen belt can have a connecting seam to create the perimeter or be woven completely uniformly around the perimeter.It is advantageous if the conveyor belt system has provisions for accommodating a continuous conveyor belt. These may include movable conveyor belt rollers or movable parts of the side walls.

[0009] It is highly preferred that each of the at least two meltblown nozzle devices is assigned a suction area. The suction areas are advantageously located below the respective meltblown nozzle device. Preferably, the conveyor belt assembly comprises at least one air channel for each meltblown nozzle device for drawing air into a respective depositing or suction area on the at least one conveyor belt. It is preferred that the at least two air channels are arranged between the upper sections and the lower, return sections of the at least one conveyor belt. The at least two air channels can be connected to a common air conveying unit or to different air conveying units. The air channels are designed to draw air through the conveyor belt(s) from top to bottom.

[0010] It is advantageous if the pivot axis is located in the middle third / quarter / fifth / sixth of the longitudinal extent of the screen belt assembly, and preferably in the center or substantially in the center of the screen belt assembly. It is preferred if the screen belt assembly is designed to pivot in a rocker-like manner around the pivot axis. It is also possible for the pivot axis to be located in a left or right third, or at a left or right end, of the screen belt assembly in a side view.

[0011] According to a preferred embodiment, the angle α between the surface of the at least one screen belt facing the meltblown nozzle devices and the horizontal H is between -10° and 10°, in particular between -8° and 8°, and preferably between -7° and 7°, and most preferably between -6° and 6°. The invention is based on the finding that the nonwoven fabric is not impaired at correspondingly small angles.

[0012] It is preferred that the vertical height difference Δh between a deposit area on the surface of the at least one sieve belt for the meltblown fibers in the inclined state of the sieve belt assembly and this deposit area in the horizontally oriented state of the sieve belt assembly is 100 to 500 mm, preferably 120 to 400 mm, and particularly preferably 140 to 350 mm. It has been found that a corresponding vertical height difference Δh is sufficient to adequately adjust the distance A1 and / or A2 for at least the vast majority of height adjustments encountered in practice.

[0013] According to one embodiment, the screen belt device comprises only an endlessly circulating screen belt, wherein the meltblown fibers from the at least two meltblown die devices are preferably deposited to form at least two layers of a meltblown nonwoven fabric. Due to the deposition of the relatively hot fibers from the second meltblown die device onto those from the first meltblown die device, a slight bonding already occurs, so that a subsequent consolidation device for better adhesion of the two layers to each other is not necessarily required.

[0014] According to a highly preferred embodiment, the sieve belt assembly comprises at least two, or optionally only two, sieve belts. It is possible for a transfer area to be located between the two sieve belts. It is advantageous if the surfaces of the two sieve belts facing the meltblown nozzle devices are aligned in a side view. It is advantageous if the two corresponding ends of the sieve belts in the transfer area have a height difference of no more than 100 mm, 70 mm, 50 mm, 30 mm, or 20 mm.

[0015] It is possible for the two or only two continuously rotating screen belts to rotate in the same or opposite directions. It may be advantageous to operate the screen belts at different speeds.

[0016] According to one embodiment, the nonwoven fabric production device or the conveyor belt device is designed such that at least one, and in particular only one, meltblown nonwoven web is guided below the conveyor belt device for at least part of its transport path. It is possible that the at least one meltblown nonwoven web is directed downwards in the transfer area and then guided below the second conveyor belt or below the return sections of the second conveyor belt over nonwoven web rollers. It is also possible that the meltblown nonwoven webs from the two or more meltblown nozzle devices are directed downwards in the transfer area and then transported away below the first and / or second conveyor belt over nonwoven web rollers.

[0017] It is possible that at least two, and in particular only two, meltblown nonwoven webs are transported only on the upper side of the conveyor belt. According to one embodiment, the at least two meltblown nonwoven webs are transported in different directions and preferably wound up separately. It is possible that the fibers of the first meltblown die assembly initially form a nonwoven web on the first conveyor belt, and are then transferred across the transfer area to the second conveyor belt, where the fibers of the second meltblown die assembly then form a second layer on the first nonwoven web or first layer.

[0018] According to a preferred embodiment, the nonwoven fabric production device is designed such that the first and second meltblown die devices produce a first and second nonwoven web respectively, wherein the first and second nonwoven webs are only joined together after leaving the screen belt device.

[0019] It is within the scope of the invention that a consolidation device, in particular a combination device for consolidation or lamination of two or more layers, is provided downstream of the screen belt device. The consolidation device can, in particular, effect chemical and / or mechanical and / or thermal consolidation of a nonwoven web or several layers of a nonwoven. Examples include a calender or needling using a fluid.

[0020] The invention relates to a nonwoven fabric production device with at least two spinning units for producing two fiber types. Such devices are already known in practice for combining the properties of two fiber types in a single nonwoven fabric. For this purpose, the fibers from the first spinning unit are laid down on a screen belt device, which has an endlessly circulating screen belt. Fibers from the second spinning unit are laid down on the fibers of the first spinning unit, so that a two-layer nonwoven fabric is formed and the properties of two different fiber types are combined in one nonwoven fabric.

[0021] However, the direct placement of the fibers from the second spinning device onto those from the first results in an undesirable thermal lamination, because the fibers from the second spinning device still retain a certain amount of heat during placement. It may be desirable, for example, to bond the two layers together only by mechanical means, such as needling. Furthermore, it may be necessary, for instance, to combine fibers from three spinning devices into a nonwoven fabric. In this case, the middle spinning device may not be intended to produce the middle of the three resulting fiber layers, but rather one of the two outer fiber layers. The invention therefore aims to eliminate the aforementioned disadvantages.

[0022] This problem is solved by a nonwoven fabric production device – in particular with at least one feature of the aforementioned nonwoven fabric production devices according to the invention – with at least two spinning devices, – in particular at least two meltblown die devices or at least two spunbond die devices or at least one meltblown die device and at least one spunbond die device – for producing fibers, wherein a screen belt device or a screen belt table is provided, in particular with at least one feature of the aforementioned screen belt devices according to the invention, wherein the fibers of the spinning devices can be deposited on the screen belt device. wherein the sieve belt device has at least two endlessly circulating sieve belts.

[0023] This invention is based on the understanding that two endlessly circulating screen belts offer a multitude of possibilities for manipulating the nonwovens being produced. For example, a first web of nonwovens from the first spinning unit can be guided downwards in a transfer area between the screen belts and beneath the second screen belt, so that the two webs are only joined after exiting the screen belt assembly. This avoids the heat lay-down of the second fibers onto the first web. Furthermore, the webs from the spinning units can be transported in different directions, allowing a web to be turned over and the layers of the nonwoven to be assembled in a different sequence. As a result, the aforementioned problems are solved.

[0024] The invention is explained in more detail below using several exemplary embodiments. The schematic representations show: Fig. 1 a side view of a nonwoven fabric production device of a first embodiment according to the invention with a first screen belt device according to the invention, Fig. 2 a perspective view of a second sieve belt device according to the invention, Fig. 3 a schematic side view of a second nonwoven fabric production device according to the invention in a first operating mode, Fig. 4 the nonwoven fabric production device Fig. 3 in a second operating mode, Fig. 5 the nonwoven fabric production device Fig. 3 in a third operating mode and Fig. 6 the nonwoven fabric production device Fig. 3 in a fourth operating mode.

[0025] In Fig. Figure 1 shows a nonwoven fabric production device according to the invention, comprising two spinning devices, in particular two meltblown die devices 1, 2 or two meltblown die beams. Below the meltblown die devices 1, 2 is a wire belt assembly 5 with only one continuously circulating wire belt 6. In this embodiment, the continuously circulating wire belt 6 is guided over eight wire belt rollers 20. The wire belt 6 has upper sections facing the meltblown die devices 1, 2, which run in one transport direction. On the underside of the wire belt assembly 5, sections of the wire belt 6 run in the opposite direction to the transport direction.

[0026] Between the upper and lower sections of the screen belt 6 are a first air duct 18 and a second air duct 19, the first air duct 18 being assigned to the first meltblown nozzle assembly and the second air duct 19 to the second meltblown nozzle assembly. The air ducts 18, 19 can be connected to each other via an air conveying unit or separated from each other by two separate air conveying units. Air is conveyed downwards in the air ducts 18, 19, so that air is drawn in from above the screen belt 6 and directed through holes in the screen belt 6 into the air ducts 18, 19. The air ducts 18, 19 are advantageously located directly below the respective depositing area or the respective meltblown nozzle assemblies 1, 2.

[0027] The first fibers 3 of the first meltblown die unit 1 initially form their own, first nonwoven web 15. As soon as the first nonwoven web 15 reaches the depositing area of ​​the second fibers 4, the second fibers 4 form a second layer 13 on the first nonwoven web 15 (= first layer 12). Once the second layer 13 has been deposited on the first layer 12, it can be referred to as a nonwoven web 14. After leaving the screen belt unit 5, the nonwoven web 14 is passed over a nonwoven web roll 21 and then fed to a bonding unit 17. The bonding unit 17 in this embodiment can be a calender whose rollers exert pressure and release heat, so that the nonwoven web 14 is a laminated nonwoven web after leaving the bonding unit 17.Due to the direct placement of the second fibers 4 onto the first fibers 3, a hot placement occurs in this embodiment, so that a first lamination already takes place during this hot placement, which is why a consolidation device 17, in particular a thermal consolidation device 17, is not required for all nonwoven products of this embodiment.

[0028] In Fig. Figure 1 shows that each of the two meltblown nozzle devices 1, 2 has an associated nozzle tip 8, 9. The nozzle tip 8 defines a vertical distance A1 between itself and the surface of the screen belt 6. Similarly, the nozzle tip 9 defines a vertical distance A2 between itself and the surface of the screen belt 6 at that point. The distances A1 and A2 must be adjustable individually and independently of each other.

[0029] For this reason, the sieve belt device 5 demonstrates Fig. 2 a pivot axis 10 and, most importantly, actuators 27, with the aid of which the entire screen belt assembly 5 can be pivoted by a position angle α. Due to the individual control of the actuators 27, not only the position angle α but also a vertical stroke Δz can be set. The two degrees of freedom α and Δz make it possible to make any desired change in the distances A1 and A2 within a certain range.

[0030] The actuators 27 may, for example, be electromechanical or hydraulic cylinders. The actuators 27 are preferably attached at their respective upper ends to side walls 24 of the screen belt assembly 5. The lower ends of the actuators 27 are preferably arranged on a slide 23, which may be mounted on rails 22. The slide 23 on the rails 22 allows for quick maintenance of the meltblown nozzle devices 1, 2 from below.

[0031] The pivot axis 10 of this embodiment may be formed by a roller which connects a pivot axis guide 25 with the associated side wall 24. The opposite side of the screen belt assembly 5, which is not shown, is expediently identical or symmetrical to the side shown in Fig. The two rollers of the pivot axis 10 support the screen belt device 5 by preventing movement in the machine direction as well as in the top view perpendicular to the machine direction.

[0032] The two pivot axis guides 25 thus only allow movements in the vertical direction, as can be seen from the indicated and slightly lowered pivot axis 10' in a groove 26 of the pivot axis guide 25. In addition, the pivot axis guide 25 naturally also permits a rotational movement, as expressed by the position angle α. It is understood that the actuators 27, not shown, move synchronously with their respective illustrated counterparts. The two actuators 27 on the right can be controlled independently of the two left actuators 27. This independent controllability is what enables the two degrees of freedom α and Δz.

[0033] In the embodiment according to Fig. Figure 2 shows that the conveyor belt assembly 5 has two endlessly circulating conveyor belts 6, 7. The two conveyor belts 6, 7 are each guided by four conveyor belt rollers 20 and form a transfer area 11 between them. It should be noted that the two conveyor belts 6, 7 can be replaced by a single conveyor belt 6, so that the configuration according to Fig. 1 is created.

[0034] In Fig. 3 is the sieve belt device 5 from Fig. Figure 2 is simplified and used in a first operating mode. Accordingly, the two screen belts 6, 7 are moved in opposite directions, so that a first nonwoven web 15 from the first fibers 3 of the first meltblown die device 1 is transported to the right and a second nonwoven web 16 from the second fibers 4 of the second meltblown die device 2 is transported to the left. It is not shown that the two nonwoven webs 15, 16 are wound up separately from each other. Consequently, it is with the in Fig. The operating method shown in section 3 makes it possible to produce two completely independent nonwovens 14.

[0035] In Fig. 4 is a second operating mode of the sieve belt device 5 from Fig. Figure 2 shows the process. Accordingly, the screen belts 6 and 7 are operated counterclockwise. The first nonwoven web 15, consisting of the first fibers 3, is deflected downwards in a transfer area. The nonwoven web 15 is then picked up by nonwoven web rollers 21 and guided under the second screen belt 7. Screen belt rollers 21 bring the two nonwoven webs 15 and 16 together, so that a nonwoven 14 with a first layer 12 and a second layer 13 is formed. The nonwoven 14 is then consolidated by a bonding device 17. This configuration prevents the heat deposition of the second fibers 4 onto the first fibers 3 or the first nonwoven web 15. Furthermore, the separate guidance of the first nonwoven web 15 makes it possible to feed the first nonwoven web 15 to a separate treatment unit (not shown) before the nonwoven webs 15 and 16 are brought together.

[0036] In Fig. 5 is different from Fig. 4. The direction of the first screen belt 6 is now oriented clockwise. This turns the first nonwoven fabric 15 relative to the second nonwoven fabric 16, which is particularly important if the first nonwoven fabric 15 is itself already multi-layered. In the case of Fig. 6 Finally, it is shown that the sieve belts 6, 7, compared to Fig. 5 opposite directions of movement are possible, so that in particular a turning of the second fleece strip 16 is also possible. Thus, the Fig. 3, Fig. 4, Fig. 5 to Fig. 6 the great flexibility that results in the case of using two sieve belts 6, 7.

Claims

[1] Nonwoven fabric production device with at least two meltblown nozzle devices (1, 2) - in particular with at least two meltblown nozzle beams - for producing meltblown fibers (3, 4), wherein a screen belt device (5) or a screen belt table is provided, which has at least one continuously circulating screen belt (6, 7), wherein the meltblown fibers (3, 4) of the meltblown nozzle devices (1, 2) can be deposited on the at least one screen belt (6, 7) of this screen belt device (5), wherein the meltblown nozzle devices (1, 2) define a vertical distance A1 or A2 between a respective nozzle tip (8, 9) and a surface of the at least one screen belt (6, 7) in a side view, wherein the sieve belt device (5) or a surface of the at least one sieve belt (6, 7) facing the meltblown nozzle devices (1, 2) is oriented or orientable obliquely in a side view with respect to a horizontal H for the purpose of changing the distance A1 and / or A2, wherein the sieve belt device (5) or the sieve belt table is pivotable for the inclined orientation or for changing the distance A1 and / or A2 about a pivot axis (10). and wherein the pivot axis (10) is arranged in the middle third, preferably in the middle or substantially in the middle of the sieve belt assembly (5) with respect to the longitudinal extent of the sieve belt assembly (5). [2] Nonwoven production device according to claim 1, wherein the pivot axis (10) is arranged in a top view perpendicular or substantially perpendicular to the machine direction (MD) or to the longitudinal extent of the screen belt device. [3] Nonwoven fabric production device according to one of claims 1 or 2, wherein the angle α between the surface of the at least one screen belt (6, 7) facing the meltblown nozzle devices (1, 2) and the horizontal H is between -10° and 10°, in particular between -8° and 8° and preferably between -7° and 7°. [4] Nonwoven production device according to one of claims 1 to 3, wherein the vertical height difference Δh between a depositing area of ​​the surface of the at least one screen belt (6, 7) for the meltblown fibers (3, 4) in the obliquely oriented state of the screen belt device (5) and this depositing area in the horizontally oriented state of the screen belt device is 100 to 500 mm and preferably 120 to 400 mm. [5] Nonwoven fabric production apparatus according to one of claims 1 to 4, wherein the screen belt apparatus (5) has at least two, in particular two, endlessly circulating screen belts (6, 7). [6] Nonwoven fabric production apparatus according to claim 5, wherein the at least two, in particular the two, endlessly rotating screen belts (6, 7) rotate in the same direction or in opposite directions. [7] Nonwoven fabric production device according to one of claims 5 or 6, wherein at least one, in particular one, meltblown nonwoven web (15, 16) is guided over at least part of its transport path below the screen belt device (5).

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