阅读说明：本技术 用于由连续长丝制造纺粘型非织造织物的设备和方法 (Apparatus and method for making spunbond nonwoven fabrics from continuous filaments ) 是由 M·尼奇克 M·诺伊恩霍费尔 H－G·戈伊斯 D·弗赖 于 2019-05-21 设计创作，主要内容包括：用于由连续长丝制造纺粘型非织造织物的设备,设置用于纺出连续长丝的纺丝头并且设有用于利用冷却空气冷却纺出的连续长丝的冷却室。在所述冷却室的两个相对置的侧上分别设置一个空气供给室,冷却空气可以从所述空气供给室中被引导到冷却室中。在每个空气供给室上连接用于冷却空气的供给管道,其横截面面积在冷却空气过渡到空气供给室中处增大到空气供给室的横截面面积,空气供给室的横截面面积是供给管道的横截面面积的至少二倍。在每个空气供给室中设置流动整流器并且与流动整流器隔开地设置平面的均匀化元件以用于使被导入到空气供给室中的冷却空气流均匀化。均匀化元件具有多个开口,均匀化元件的自由通流面积为均匀化元件的总面积的1％至40％。(An apparatus for producing a spunbonded nonwoven fabric from continuous filaments is provided with a spinning head for spinning the continuous filaments and with a cooling chamber for cooling the spun continuous filaments with cooling air. An air supply chamber is provided on each of two opposite sides of the cooling chamber, from which cooling air can be conducted into the cooling chamber. A supply line for cooling air is connected to each air supply chamber, the cross-sectional area of which increases to the cross-sectional area of the air supply chamber at the transition of the cooling air into the air supply chamber, the cross-sectional area of the air supply chamber being at least twice the cross-sectional area of the supply line. A flow straightener is arranged in each air supply chamber and a planar homogenization element is arranged at a distance from the flow straightener for homogenizing the cooling air flow introduced into the air supply chamber. The homogenizing element has a plurality of openings, the free flow area of the homogenizing element being 1% to 40% of the total area of the homogenizing element.)

1. An apparatus for producing a spunbonded nonwoven fabric from continuous filaments (1), in particular from continuous filaments (1) made of thermoplastic, wherein a spinneret (2) for spinning the continuous filaments (1) is provided and a cooling chamber (4) is present for cooling the spun continuous filaments (1) with cooling air, wherein one air supply chamber (5, 6) is provided on each of two opposite sides of the cooling chamber (4) and cooling air can be introduced into the cooling chamber (4) from the opposite air supply chambers (5, 6),

And to each air supply chamber at least one supply line (22) for supplying cooling air is connected, which supply line has a cross-sectional area QZ, wherein the cross-sectional area QZ increases to a cross-sectional area QL of the air supply chamber (5, 6) at the transition of the cooling air into the air supply chamber (5, 6), wherein the cross-sectional area QL is at least twice, preferably at least three times, the cross-sectional area QZ of the supply line (22),

Wherein at least one flow straightener (18) arranged upstream of the cooling chamber (4) is provided in each air supply chamber (5, 6), wherein at least one planar homogenization element (23) for homogenizing the cooling air flow introduced into the air supply chamber (5, 6) is provided in the air supply chamber (5, 6) upstream of the flow straightener (18) in the flow direction of the cooling air and at a distance from the flow straightener (18), and the planar homogenization element (23) has a plurality of openings, wherein the free flow area of the planar homogenization element (23) is 1% to 40%, preferably 2% to 35% and preferably 2% to 30% of the total area of the planar homogenization element (23).

2. Apparatus according to claim 1, wherein a drawing device (8) is connected to the cooling chamber (4) in the flow direction of the filaments (1), and the cooling chamber (4) and the drawing device (8) are configured as a closed system into which no further air supply takes place other than the air supply supplying cooling air into the cooling chamber (4).

3. The apparatus of claim 1 or 2, wherein the air supply chamber (5, 6) has a height H or vertical height H of 400mm to 1500mm, preferably 500mm to 1200mm and preferably 600mm to 1000 mm.

4. Apparatus according to any one of claims 1 to 3, wherein the cross-sectional area QZ of the supply duct (22) is enlarged by a factor of 3 to 15 by the cross-sectional area QL of the air supply chamber (5, 6).

5. The device according to one of claims 1 to 4, wherein the flow straightener (18) has a plurality of flow channels (19) oriented transversely to the direction of movement of the filaments (1) or filament stream, wherein the flow channels (19) are defined by channel walls (20) and the flow area of the flow straightener (18) is preferably greater than 85%, preferably greater than 90%, and preferably the ratio L/D of the length L of the flow channels (19) to the inner diameter D of the flow channels (19) is 1 to 15, preferably 1 to 10 and preferably 1.5 to 9.

6. the apparatus as claimed in one of claims 1 to 5, wherein the cooling air volume flow fed to an air feed chamber (5, 6) is divided into partial volume flows which flow in through individual partial feed ducts and/or through segments of a segmented feed duct.

7. The apparatus according to claim 6, wherein the cooling air volume flow is divided into two to five, preferably two to three partial volume flows.

8. The apparatus according to claim 6 or 7, wherein the cooling air of at least two partial volume flows has different air speeds and/or different air temperatures and/or different air humidities.

9. The apparatus as claimed in one of claims 1 to 8, wherein the air supply chamber (5, 6) is divided into at least two, preferably two, chamber sections (16, 17), from which preferably cooling air of different temperatures can be supplied respectively, and each chamber section (16, 17) can be supplied with at least one partial volume flow of cooling air.

10. The apparatus according to any one of claims 1 to 9, wherein at least one homogenizing element (23) is configured as an apertured element, in particular as an apertured plate (24) having a plurality of aperture openings (25), and the aperture openings (25) preferably have an opening diameter d of 1mm to 10mm, preferably 1.5mm to 9mm and very preferably 1.5mm to 8 mm.

11. The apparatus according to one of claims 1 to 10, wherein the homogenizing element (23) is configured as a homogenizing screen having a plurality or a multiplicity of meshes (27), wherein the homogenizing screen preferably has a mesh width (26) of 0.1mm to 0.5mm, preferably 0.12mm to 0.4mm and very preferably 0.15mm to 0.35 mm.

12. Apparatus according to any one of claims 1 to 11, wherein the at least one planar homogenizing element (23) is arranged upstream of the flow rectifier (18) of the respective air supply chamber (5, 6) in the flow direction of the cooling air by a distance a1 of at least 50mm, preferably at least 80mm and preferably at least 100 mm.

13. The apparatus according to any one of claims 1 to 12, wherein a plurality of homogenizing elements (23) are arranged in the air supply chamber (5, 6) one after the other in the flow direction of the cooling air at a distance from the flow rectifier (18) and at a distance from one another.

14. Apparatus according to claim 13, wherein the distance ax between two homogenizing elements (23) arranged one after the other in the flow direction in one air feed chamber (5, 6) is at least 50mm, preferably at least 80mm and preferably at least 100 mm.

15. apparatus according to claim 13 or 14, wherein the free flow area of the successive homogenization elements (23) increases from homogenization element (23) to homogenization element (23) towards the associated flow straightener (18).

16. The device according to any one of claims 1 to 15, wherein the area of the homogenizing element (23) extends at least over a large part of the cross-sectional area QL of the associated air feed chamber (5, 6) or of the associated chamber section (16, 18) of the air feed chamber (5, 6).

17. The device according to any one of claims 1 to 16, wherein the cross-sectional area QZ of the supply conduit (22) enlarges stepwise, in particular in the form of a plurality of steps or continuously, to the cross-sectional area QL of the air supply chamber (5, 6) or to the cross-sectional area of the chamber section (16, 17) of the air supply chamber (5, 6).

18. a method for producing a spunbonded nonwoven from continuous filaments (1), in particular from continuous filaments (1) made of thermoplastic, wherein the continuous filaments (1) are spun from a spinneret and cooled in a cooling chamber (4) by means of cooling air, wherein the cooling air is introduced into the cooling chamber (4) from air supply chambers (5, 6) arranged on opposite sides of the cooling chamber (4),

Wherein the cooling air is guided in the air supply chamber (5, 6) through at least one planar homogenizing element (23) for homogenizing the cooling air, the planar homogenizing element (23) having a plurality of openings, and the free flow area of the planar homogenizing element (23) being 1% to 40%, preferably 2% to 35% and preferably 2% to 30% of the total area of the planar homogenizing element (23),

and cooling air is introduced into the cooling chamber (4) after the at least one planar homogenizing element (23) by means of a flow rectifier (18).

19. The method according to claim 18, wherein the filaments are loaded in a cooling chamber (4) with cooling air having an air velocity of 0.15 to 3m/s, preferably 0.15 to 2.5m/s and preferably 0.17 to 2.3 m/s.

20. Method according to claim 18 or 19, wherein the filaments are loaded in the cooling chamber (4) with a cooling air volume flow of 200m3/h/m to 14000m3/h/m, preferably 250m3/h/m to 13000m3/h/m and preferably 300m3/h/m to 12000m 3/h/m.

Technical Field

The invention relates to a device for producing a spunbonded nonwoven fabric from continuous filaments, in particular from continuous filaments made of thermoplastic, wherein a spinneret for spinning out the continuous filaments is provided and a cooling chamber for cooling the spun-out continuous filaments with cooling air is provided, wherein an air supply chamber is provided on each of the opposite sides of the cooling chamber, wherein the cooling air can be introduced into the cooling chamber from the opposite air supply chamber and at least one supply line for supplying cooling air is connected to each air supply chamber. The invention also relates to a corresponding method for producing a spunbonded nonwoven from continuous filaments. Spunbonded nonwoven fabrics are in the context of the present invention particularly spunbonded nonwovens produced according to the spunbonding process. Continuous filaments differ from staple fibers having a significantly shorter length (e.g., 10mm to 60mm) due to their length, which can be said to be infinitely long.

Background

Devices and methods of the type mentioned at the outset are known in practice in principle in different embodiments. However, many of the known devices and methods have the following disadvantages: the spunbond nonwoven fabric produced in this way is not always sufficiently uniform or homogeneous in its surface extension. Spunbond nonwoven fabrics often made in the manner described have disturbing nonuniformities in the form of defects or imperfections. The amount of non-uniformity generally increases with production capacity or with increasing yarn speed. The typical defects in such spunbond nonwoven fabrics are produced by so-called "droplets". The droplets are caused by the breaking of one or more soft or molten filaments, thereby creating melt buildup that creates defects in the spunbond nonwoven fabric. Such spots based on "droplets" usually have a size of more than 2mm x 2 mm. On the other hand, defects in the nonwoven fabric may also be produced by so-called "hard lumps". The hard block is formed by: the filaments may relax through stress loss, snap back and form spheres that create defect points in the surface of the spunbond nonwoven. Such defects are typically less than 2mm x 2 mm.

Disclosure of Invention

in contrast, the invention is based on the technical problem of specifying an apparatus of the type mentioned at the outset with which very uniform and homogeneous spunbonded non-woven fabrics can be produced, which are configured to be defect-free or defect-free at high throughputs of more than 200kg/h/m or at high thread speeds, at least to a large extent. The invention is based on the technical problem, inter alia, of specifying a corresponding method for producing a spunbonded nonwoven from continuous filaments.

In order to solve the stated problem, the invention teaches an apparatus for producing a spunbonded nonwoven from continuous filaments, in particular from continuous filaments made of thermoplastic, wherein a spinning head is provided for spinning the continuous filaments and a cooling chamber is provided for cooling the spun continuous filaments with cooling air, wherein an air supply chamber is provided on each of the two opposite sides of the cooling chamber and cooling air can be introduced into the cooling chamber from the opposite air supply chambers,

And to each air supply chamber there is connected at least one supply duct for supplying cooling air, which supply duct has a cross-sectional area QZ, wherein said cross-sectional area QZ of the supply duct increases to a cross-sectional area QL of the air supply chamber at the transition of the cooling air into the air supply chamber, wherein said cross-sectional area QL is at least twice, preferably at least three times, the cross-sectional area QZ of the supply duct,

Preferably, at least one flow straightener is provided in each air supply chamber upstream of the cooling chamber, wherein at least one planar homogenization element for homogenizing the cooling air flow introduced into the air supply chamber is provided in the air supply chamber upstream of the flow straightener in the flow direction of the cooling air and at a distance from the flow straightener, and the planar homogenization element has a plurality of openings, wherein the free flow area of the planar homogenization element is 1% to 40%, preferably 1.5% to 40%, more preferably 2% to 35%, particularly preferably 2% to 30% and in particular 2% to 25% of the total area of the planar homogenization element.

Suitably, the height H or vertical height H of the air supply chamber is from 400mm to 1500mm, preferably from 500mm to 1200mm and preferably from 600mm to 1000 mm. A particularly preferred embodiment of the invention is characterized in that the height H or vertical height H of the air supply chamber is between 700mm and 900 mm. Within the scope of the invention, the air supply chamber is divided, at its height H, into chamber sections, which are described further below, and which are arranged one above the other or vertically above one another. Expediently, in addition to the height H, the features given above and the preferred embodiments listed below apply to the air supply chamber and preferably also to each chamber section.

furthermore, it is within the scope of the invention that the cooling air supply for the cooling chamber is effected on the basis of the movement of the thread or the downwardly directed flow of the thread by sucking in cooling air and/or by actively blowing in or introducing cooling air, for example by means of at least one fan. If a fan for blowing in cooling air is used, it is recommended to have an adjustable fan, by means of which in particular the volume flow of the cooling air introduced can be adjusted. According to one embodiment of the invention, the cooling air is blown or introduced by a plurality of fans.

Suitably, the cross-sectional area QZ of the supply conduit is enlarged by a factor of 3 to 15, preferably 4 to 15 and more preferably 5 to 15 to the cross-sectional area QL of the air supply chamber.

Furthermore, it is within the scope of the invention for at least one homogenization element or the homogenization element to be configured as an opening element or opening plate and/or homogenization screen. The apertured element or plate, which is constructed as a homogenizing element, is equipped with a plurality or a plurality of apertures. Preferably, the hole openings each have an opening diameter of 1mm to 12mm, suitably 1mm to 10mm, preferably 1.5mm to 9mm and particularly preferably 1.5mm to 8 mm. If a plurality of opening diameters can be measured for the bore opening on the basis of its geometry, the invention is referred to herein as the smallest opening diameter d of the bore opening. If the orifice openings of the homogenizing element have different diameters, the opening diameter d or the smallest opening diameter d is expediently referred to as the mean opening diameter d or the mean smallest opening diameter d. If the homogenizing element is configured as a homogenizing screen, it has a plurality or a plurality of mesh openings. It is recommended that these homogenizing sieves have a mesh width of 0.1mm to 0.6mm, preferably 0.1mm to 0.5mm, preferably 0.12mm to 0.4mm and very preferably 0.15mm to 0.35 mm. The mesh width here refers to the distance between two opposite wires of the mesh and in particular to the minimum distance between two opposite wires of the mesh. Thus, for example, when the mesh has a rectangular cross-sectional area with rectangular sides of different lengths, the mesh width between the two longer rectangular sides is measured. When the meshes of the homogenizing screen have different mesh widths, the mesh width refers in particular to the average mesh width of the meshes of the homogenizing screen. Preferably, the homogenizing screen has a wire thickness or average wire thickness of 0.05mm to 0.4mm, preferably 0.06mm to 0.35mm and very preferably a wire thickness of 0.07mm to 0.3 mm.

Furthermore, within the scope of the invention, a plurality of planar homogenization elements are arranged in the air supply chamber at a distance from the flow straightener of the air supply chamber, to be precise preferably in the air supply chamber one after the other in the flow direction of the cooling air and at a distance from one another. The surfaces of the planar homogenization elements arranged at a distance in the air supply chamber are expediently arranged parallel to one another or substantially parallel to one another or at least approximately parallel to one another. Within the scope of the invention, the surface of the planar homogenization element is arranged in the respective air supply chamber transversely to the flow direction of the cooling air and, according to a preferred embodiment, is arranged in the air supply chamber perpendicularly or substantially perpendicularly to the flow direction of the cooling air.

according to a preferred embodiment of the invention, the at least one planar homogenizing element arranged in the air supply chamber is arranged upstream of the flow straightener of the respective air supply chamber in the flow direction of the cooling air by a distance a 1. The distance a1 is greater than 0 and preferably greater than 10 mm. Suitably, the distance a1 is at least 50mm, preferably at least 80mm and preferably at least 100 mm. According to a particularly preferred embodiment of the invention, when a plurality of planar homogenization elements are arranged in the air supply chamber, the distance a1 relates to the homogenization element arranged closest upstream of the flow straightener. If the homogenizing element arranged upstream of the flow straightener by the distance a1 is to be a homogenizing screen, it is to be distinguished from possible flow screens of the flow straightener. Such a flow screen or such a flow screen of a flow straightener is also described in detail below.

According to a very preferred embodiment of the invention, a plurality of homogenization elements are arranged in succession in the air supply chamber. Expediently, the distance ax between two homogenizing elements arranged one after the other in the flow direction in an air feed chamber is at least 40mm, preferably at least 50mm, preferably at least 80mm and very preferably at least 100 mm. It is pointed out that the planar homogenization elements according to the proven embodiment are arranged transverse and, according to a preferred embodiment, perpendicular or substantially perpendicular to the flow direction of the cooling air.

According to the invention, the free flow area of the planar homogenization elements (in particular the opening elements or the opening plates and/or the homogenization screen) is 1% to 40%, preferably 2% to 35% and preferably 2% to 30% of the total area of the planar homogenization elements. According to a preferred embodiment, the free flow area of the planar homogenizing elements amounts to 2% to 25%, preferably 2% to 20% and in particular 2% to 18% of the total area of the planar homogenizing elements. The free flow area is understood within the scope of the invention to mean an area through which cooling air can flow freely and is therefore preferably not blocked by plate elements, wire elements or the like. A very preferred embodiment of the invention is characterized in that the free flow area of the homogenizing elements arranged one after the other in the air supply chamber increases from homogenizing element to homogenizing element towards the flow straightener or towards the cooling chamber. Expediently, the homogenizing element having the smallest distance to the flow straightener or to the cooling chamber has the largest free flow area of all homogenizing elements.

Within the scope of the invention, the area of the homogenization element (in particular the opening element or the opening plate and/or the homogenization screen) extends at least over a large part of the cross-sectional area QL of the associated air supply chamber or over a large part of the cross-sectional area of the associated chamber section of the air supply chamber. A proven embodiment of the invention is characterized in that the area of the homogenizing element extends over the entire cross-sectional area or substantially the entire cross-sectional area of the associated air supply chamber or of the associated chamber section of the air supply chamber.

Within the scope of the invention, the cooling air flowing into the air supply chamber or the chamber section of the air supply chamber is distributed, in particular uniformly distributed, over the width and height of the air supply chamber or the chamber section. According to a preferred embodiment of the invention, the cross-sectional area QZ of the supply line widens stepwise to the cross-sectional area QL of the air supply chamber or to the cross-sectional area of the chamber section of the air supply chamber. According to a further preferred embodiment, the cross-sectional area QZ of the supply line is continuously enlarged to the cross-sectional area QL of the air supply chamber or to the cross-sectional area of the chamber section of the air supply chamber. In this case, according to one embodiment variant, a stepped and/or continuous enlargement of the cross-sectional area is achieved along all four side walls which define the cross-section of the square air supply chamber. Furthermore, it is within the scope of the invention for the cross-section QZ of the supply conduit to be configured round and preferably circular in cross-section. In principle, the cross section of the supply line can be geometrically designed in different ways, for example rectangular.

The invention is based on the recognition that: according to the configuration of the air supply chamber according to the invention, an optimized homogenization of the cooling air and, in particular, a good uniform distribution of the cooling air over a small space can be achieved. In this connection, the invention is also based on the recognition that: the homogenization of the cooling air flow according to the invention advantageously affects the spun thread with regard to the solution of the technical problem. A high-quality filament or nonwoven fleece layer is ultimately obtained and defects or flaws in the nonwoven fleece layer can be avoided or at least largely minimized. The invention is also based on the recognition that: an optimized homogenization of the cooling air flow is achieved by the combination of the features according to the invention and firstly by the combination of the homogenization element arranged on the one hand in the air supply chamber and on the other hand according to the invention with an enlarged cross-sectional area. In addition, the flow straightener arranged in the air supply chamber contributes very effectively to the homogenization of the cooling air flow. By means of the homogenizing element according to the invention, a pre-orientation of the cooling air flow upstream of the flow straightener is promoted to a certain extent, so that a more efficient use of the flow straightener is clearly enabled. Turbulence in the cooling air flow can be largely avoided and can also be influenced by the inventive configuration of the air supply chamber, since an undesired asymmetrical air flow profile can be prevented. The result is that an optimized introduction of the air volume flow into the cooling chamber is achieved by the configuration of the air supply chamber. An undesired feed error with respect to the cooling air feed can be compensated for simply and without problems. This also involves undesirable supply differences between the opposing air supply chambers. In this respect, the "tolerance-tolerant configuration" is achieved to some extent by the design of the cooling device according to the invention with a cooling chamber and an air supply chamber. The homogenizing element arranged in the air supply chamber fulfils the purpose of the pressure consumer to a certain extent. The desired blowing profile or cooling air velocity profile can also be set in a targeted manner by means of these homogenizing elements. It is thus possible without problems, for example, to implement a block profile in which the air speed is identical or somewhat identical at all locations. "bulging" and asymmetrical cooling air velocity profiles are also possible.

According to a preferred embodiment of the invention, a predistribution of the cooling air is effected when the cooling air is introduced into the air supply chamber, in particular upstream of the homogenizing element. This enables the upstream assistance of the homogenization element or the pressure consumer to be achieved to a certain extent. In this context, flow elements in the form of pointed wedge channels, gap channels with gap plate covers and outflow pyramids or the like can be used as predistribution elements. The supply line for the cooling air can also be constructed in sections for this purpose. In this respect, the pipe can also be provided with vanes in the region of the reversal of the supply line. In principle, the installation of the blades can be continued in the air supply chamber, which then results in particular in a segmentation of the air supply chamber.

A preferred embodiment of the invention is characterized in that the cooling air volume flow supplied to the air supply chamber is divided into a plurality of partial volume flows. Within the scope of the invention, these partial volume flows are fed in via individual partial supply lines and/or via sections of a segmented supply line. Furthermore, it is within the scope of the invention for the air supply chamber to be divided into a plurality of chamber sections in accordance with the partial volume flow to be supplied, wherein each chamber section is expediently assigned to a partial volume flow. According to a preferred embodiment, the cooling air volume flow is divided into two to five, in particular two to four and preferably two to three partial volume flows. Suitably, the air speed and/or air temperature and/or air humidity of each partial volume flow is adjusted individually and suitably adapted to the respective process requirements. Preferably, the cooling air of the at least two partial volume flows has different air speeds and/or different air temperatures and/or different air humidities. Within the scope of the invention, each partial volume flow of cooling air is assigned a chamber section of the air supply chamber, which opens into the flow straightener. According to a particularly preferred embodiment of the invention, the flow straightener or the continuous flow straightener extends over all chamber sections and thus, expediently, the height or vertical height of the associated air supply chamber.

Within the scope of the invention, at least one homogenization element, preferably a plurality of homogenization elements, is arranged in each chamber section of the air supply chamber. The homogenization element can extend continuously over the entire height of the air supply chamber, or separate homogenization elements can be provided in the individual chamber sections. In other aspects, all of the features of the homogenizing element described herein also apply to homogenizing elements provided in a single chamber section. Expediently, a plurality of homogenization elements are present in each chamber section, which are arranged one after the other in the flow direction of the cooling air.

A very preferred embodiment of the invention is characterized in that the air supply chamber or each of the two opposing air supply chambers is divided into at least two, preferably two, chamber sections. Preferably, cooling air of different temperatures or air temperatures can be supplied from the chamber sections. Within the scope of the invention, each chamber section can be supplied with at least one partial volume flow of cooling air.

Furthermore, within the scope of the invention, the air velocity and/or the air volume flow is uniform or substantially uniform or uniform to some extent over the entire width of the apparatus in the CD direction (transverse to the machine direction MD) over a certain height of the cooling chamber or the air supply chamber. It is of course possible for the cooling air speed and/or the cooling air volume flow to be different at the height or vertical height of the cooling chamber or the air supply chamber.

According to the invention, at least one flow straightener is arranged in each air supply chamber upstream of the cooling chamber in the air flow direction. According to a preferred embodiment of the invention, the flow straightener has a plurality of flow channels oriented transversely, preferably perpendicularly or essentially perpendicularly, to the direction of movement of the filaments or to the filament stream, wherein the flow channels are defined by channel walls. Preferably, the flow area of the flow straightener is greater than 85% and preferably greater than 90% of the total or cross-sectional area of the flow straightener. It is recommended that the flow area of the flow straightener is greater than 91%, preferably greater than 92% and particularly preferably greater than 92.5%. The flow area of the flow straightener is in particular the flow cross section of the flow straightener through which cooling air can freely flow, which is not blocked by the passage walls or the thickness of the passage walls and/or spacers which may be arranged between the flow passages or between the passage walls. In particular, no flow screen arranged on the flow straightener and in particular on the flow straightener upstream or downstream of the flow straightener is taken into account when calculating the flow area. Within the scope of the invention, the flow screen is omitted when calculating the flow area of the flow straightener. According to a preferred embodiment, the ratio L/Di of the length L of the flow channel of the flow straightener to the inner diameter Di of the flow channel is 1 to 15, preferably 1 to 10 and preferably 1.5 to 9. For the flow channels of the flow straightener, the inner diameter is measured from one channel wall to the opposite channel wall. The inner diameter Di suitably refers to the smallest inner diameter Di of the flow channel, if a number of different inner diameters can be measured in the flow channel depending on its cross-sectional area. Thus, if the flow channel has different inner diameters with respect to its cross section, the term "minimum inner diameter Di" relates to the smallest inner diameter measured in the flow channel. The minimum internal diameter Di is therefore measured in the cross section of the regular hexagonal form between two opposite sides and not between two opposite corners of the hexagon. The minimum internal diameter Di refers in particular to the smallest internal diameter or the average smallest internal diameter which takes an intermediate value with respect to the plurality of flow channels if the smallest internal diameter varies in the respective flow channel.

A preferred embodiment of the invention is characterized in that the flow straightener has at least one flow screen on its cooling air inflow side and/or on its cooling air outflow side. The flow screen or the surface area of the flow screen is expediently arranged transversely and preferably perpendicular or substantially perpendicular to the longitudinal direction of the flow channel of the flow straightener. According to a particularly preferred embodiment, the flow straightener has such a flow screen both on its cooling air inflow side and on its cooling air outflow side. The flow screen is expediently arranged directly on the flow straightener and without a distance from the flow straightener. Preferably, the flow screen has a mesh width of 0.1mm to 0.5mm, suitably 0.1mm to 0.4mm and preferably 0.15mm to 0.34 mm. The mesh width here refers to the distance between two opposite (metal) wires of the mesh and in particular to the minimum distance between two opposite wires of the mesh. Preferably, the flow screen has a wire thickness of 0.1mm to 0.5mm, preferably 0.1mm to 0.4mm and very preferably 0.15mm to 0.34 mm. The flow screen of the flow straightener should be distinguished from the homogenizing screen arranged in the air feed chamber. According to a preferred embodiment, the flow straightener has at least one flow screen, preferably two flow screens, and additionally at least one homogenization element and very preferably a plurality of homogenization elements are arranged in the associated air supply chamber.

According to the invention, the continuous filaments are spun by means of a spinning head and fed to a cooling chamber for cooling the filaments with cooling air. Within the scope of the invention, at least one spinning beam for spinning the thread is arranged transversely to the machine direction (MD direction). According to a very preferred embodiment of the invention, the spinning beam is oriented perpendicular or substantially perpendicular to the machine direction. It is also possible within the scope of the invention for the spinning beam to be arranged obliquely to the machine direction. A preferred embodiment of the invention is characterized in that at least one monomer suction device is arranged between the spinning head and the cooling chamber. By means of this monomer suction device, air is sucked out of the filament forming space below the spinning head. Thus, gases (such as monomers, oligomers, decomposition products, etc.) present in addition to the continuous filaments can be removed from the apparatus. The monomer suction device preferably has at least one suction chamber, to which suitably at least one suction fan is connected. It is recommended that a cooling chamber according to the invention with an air supply chamber is attached to the individual suction devices in the flow direction of the filaments. Suitably, the filaments are guided from the cooling chamber into a drawing device for drawing the filaments. Within the scope of the invention, an intermediate duct is connected to the cooling chamber, which intermediate duct connects the cooling chamber to the drawing shaft of the drawing device.

A more particularly preferred embodiment of the invention is characterized in that the combination of the cooling device and the drawing device or the combination of the cooling device, the intermediate channel and the drawing shaft is designed as a closed system. A closed system is understood here to mean, in particular, that no further air supply into the assembly takes place beyond the supply of cooling air into the cooling chamber. The homogenization of the cooling air flow according to the invention is very advantageous in particular in such closed systems. In particular, in such closed systems, spunbond nonwoven fabrics are obtained which have very uniform defect-free properties.

According to a preferred embodiment of the invention, at least one diffuser is connected to the drawing device in the flow direction of the threads, through which diffuser the threads are guided. Suitably, the diffuser comprises a diffuser cross-section or diverging diffuser section that diverges in the direction of filament lay. Within the scope of the invention, the threads are laid on a laying device for laying the threads or for laying the nonwoven fabric. Suitably, the laying means is a laying screen belt or an air permeable laying screen belt. By means of the laying device or by means of the laying screen belt, the nonwoven web of filaments is transported away in the Machine Direction (MD).

it is recommended that process air be sucked through the laying device or the laying screen belt in the laying region of the filaments or from below. This makes it possible to achieve a particularly stable filament deposition or nonwoven deposition. The suction is of particularly advantageous importance in combination with the homogenization of the cooling air flow according to the invention. After deposition on the deposition device, the filament deposition body or the nonwoven web is expediently conveyed to further processing, in particular calendering.

In order to solve the stated object, the invention also teaches a method for producing a spunbonded nonwoven from continuous filaments, in particular from continuous filaments made of thermoplastic, wherein the continuous filaments are spun from a spinneret and cooled in a cooling chamber with cooling air, wherein the cooling air is conducted into the cooling chamber from an air supply chamber arranged on the opposite side of the cooling chamber,

And the cooling air in the air supply chamber is guided through at least one planar homogenization element for homogenizing the cooling air, wherein the planar homogenization element has a plurality of openings and the free flow area of the planar homogenization element is 1% to 40%, preferably 2% to 35% and preferably 2% to 30% of the total area of the planar homogenization element, and the cooling air is introduced into the cooling chamber after the at least one planar homogenization element, preferably by means of a flow rectifier.

A particularly preferred embodiment of the method according to the invention is characterized in that the filaments are impinged in the cooling chamber by cooling air having an air velocity of 0.15 to 3m/s, preferably 0.15 to 2.5m/s and preferably 0.17 to 2.3 m/s. Suitably, the air velocity (in m/s) is measured by means of a vane anemometer having a diameter d of 80mm, more precisely on a grid of 100 x 100 mm. The air speed is measured off-line and therefore without the thread passing through the cooling chamber. In the off-line state, the velocity vector of the cooling air is preferably oriented perpendicular or substantially perpendicular to the longitudinal central axis of the apparatus or the filament flow direction FS. A preferred embodiment of the method according to the invention is characterized in that the filaments are subjected to a cooling air volume flow of 200m3/h/m to 14000m3/h/m, preferably 250m3/h/m to 13000m3/h/m and more preferably 300m3/h/m to 12000m3/h/m in the cooling chamber. Here, m3/h/m refers to the volume flow per meter of cooling chamber width. Here, the cooling chamber width extends transversely to the machine direction and thus in the CD direction.

The following is an exemplary embodiment of the device according to the invention with typical cooling air inflow parameters, which has two chamber sections of two opposite air supply chambers, which are arranged one above the other. In this case, cooling air of different temperatures is supplied to the upper chamber section and the lower chamber section. The temperature of the cooling air of the two opposite chamber sections is matched here. Typical parameters for producing continuous filaments made of polyethylene terephthalate (PET) are given on the one hand and for producing continuous filaments made of polypropylene on the other hand. In the polypropylene mode of operation, the preferred minimum values (left column) and the preferred maximum values (right column) are additionally listed. The cooling air volume flows respectively present there relate to volume flows entering from two opposite chamber sections. The height of the chamber sections, the cooling air volume flow and the cooling air velocity are given in the table below.

Upper chamber section

Lower chamber section

		PET	PP (minimum)	PP (Max)
					Height	mm	600	600	600
Volumetric flow of air	m3/h/m	11000	3000	8000
					Velocity of cooling air	m/s	2.04	0.56	1.48

When continuous filaments made of polypropylene (PP) are produced with the process according to the invention, the cooling air velocity in the air supply chamber or in the chamber section of the air supply chamber is preferably from 0.25 to 1.9m/s, suitably from 0.3 to 1.8m/s and preferably from 0.35 to 1.7 m/s. In the production of PP continuous filaments, the cooling air volume flow is preferably from 500m3/h/m to 9500m3/h/m, preferably from 600m3/h/m to 8300m3/h/m and particularly preferably from 650m3/h/m to 8100m 3/h/m. When continuous filaments made of polyester are produced with the process according to the invention, the cooling air velocity is preferably from 0.15 to 3m/s and preferably from 0.15 to 2.5 m/s. In the production of polyester continuous filaments, the cooling air volume flow is preferably from 200m3/h/m to 14000m3/h/m and preferably from 250m3/h/m to 13000m 3/h/m.

According to a preferred embodiment of the invention, the same air quantity or substantially the same air quantity and thus the same cooling air volume flow or substantially the same cooling air volume flow are introduced from two opposite air supply chambers or two opposite chamber sections. However, it is also possible to supply different cooling air volume flows from two opposite air supply chambers or chamber sections. The distribution of the cooling air volume flow can then be between 40% and 60% with respect to the opposing air supply chambers or opposing chamber sections (asymmetrical cooling air introduction). According to a further embodiment variant, an asymmetrical cooling air supply can also be realized by: the upper region of the air supply chamber or chamber section is shaded, wherein the shading can be performed over a height of up to 100 mm. Furthermore, the asymmetrical relationship can be set in such a way that the opposing air supply chambers or chamber sections are arranged at a height offset from one another. The height offset may be up to 100 mm. Furthermore, a lateral offset of up to 100mm (in the CD direction) of the air supply chamber or chamber section is also possible. Furthermore, the above measures can also be combined with each other. Furthermore, within the scope of the invention, the edge area can be shaded with respect to the width of the air supply chamber or chamber section in the CD direction. The introduction of cooling air into the cooling chamber can thus be effected uniformly and homogeneously over 85% to 90% of the CD width, but can be regulated separately in the edge regions.

in the context of the method according to the invention, the filaments or the spunbonded nonwoven can be operated at a yarn or filament speed of more than 2000m/min, in particular of more than 2200m/min or of more than 2500m/min, if they are made of a polyolefin, in particular of polypropylene. Yarn speeds of more than 4000m/min, in particular more than 5000m/min, can be achieved if the filaments or the spunbonded nonwoven are made of polyester, in particular of polyethylene terephthalate (PET), within the scope of the invention. The yarn speed can be achieved in particular without a loss of quality during the measures according to the invention. Within the scope of the invention, the device according to the invention is designed or designed such that it can be operated at the yarn speed. The design according to the invention of the air supply chamber has proved particularly advantageous at high yarn speeds. According to one embodiment of the method according to the invention, the process is operated at a throughput of more than 150kg/h/m or more than 200 kg/h/m.

The invention is based on the recognition that: with the device according to the invention and with the method according to the invention, it is possible to achieve spunbonded non-woven fabrics which are of excellent quality and have very uniform properties, in particular over their surface extension. Spunbond nonwoven fabrics can be made largely defect-free or defect-free within the scope of the present invention or at least can largely minimize defects or imperfections. It is to be emphasized in particular here that these advantages can also be achieved at the high filament speeds mentioned above and at high production capacities. The advantageous properties of the resulting spunbonded nonwoven can be achieved by the inventive configuration of the air supply chamber and by the inventive homogenization of the cooling air flow. The invention is based on the recognition that: the homogenization of the cooling air influences the filaments very positively, so that defects or defects in the nonwoven web can ultimately be prevented or largely minimized. Homogenization of the cooling air can be achieved by relatively inexpensive and nevertheless effective measures. This results in the device according to the invention also being characterized by a small device configuration and low cost. Correspondingly, the method according to the invention can also be carried out relatively simply and with little effort.

Drawings

The invention is explained in more detail below with the aid of the accompanying drawings, which illustrate only one exemplary embodiment. The figures show in schematic form:

Figure 1 shows a longitudinal section of the device according to the invention,

Figure 2 shows an enlarged part of the cooling device of figure 1 comprising a cooling chamber and an air supply chamber,

Figure 3 shows a section through a first embodiment of the air supply chamber,

Figure 4 shows a second implementation form of the content according to figure 3,

Figure 5 shows in section a segmented supply conduit with connected air supply chambers,

FIG. 6 shows a perspective view of a combination of flow straighteners with flow screens connected upstream and downstream, and

Fig. 7 shows a cross-sectional area of a flow rectifier section.

Detailed Description

The drawing shows an apparatus according to the invention for producing a spunbonded nonwoven from continuous filaments 1, in particular from continuous filaments 1 made of thermoplastic. The apparatus comprises a spinning head 2 for spinning continuous filaments 1. The spun continuous filaments 1 are introduced into a cooling device 3 having a cooling chamber 4 and air supply chambers 5, 6 provided on two opposite sides of the cooling chamber 4. The cooling chamber 4 and the air supply chambers 5, 6 extend transversely to the machine direction MD of the apparatus and thus in the CD direction of the apparatus. The cooling air is introduced into the cooling chamber 4 from the opposed air supply chambers 5, 6.

A monomer suction device 7 is preferably and in this embodiment arranged between the spinning head 2 and the cooling device 3. The interfering gases occurring during the spinning process can be removed from the apparatus by means of the monomer suction device 7. The gas may be, for example, monomers, oligomers or decomposition products and the like.

Downstream of the cooling device 3 in the filament flow direction FS, a drawing device 8 is connected, in which the filaments 1 are drawn. The stretching device 8 preferably and in this embodiment has an intermediate channel 9 which connects the cooling device 3 with a stretching shaft 10 of the stretching device 8. According to a particularly preferred embodiment and in this exemplary embodiment, the combination comprising the cooling device 3 and the drawing device 8 or the combination comprising the cooling device 3, the intermediate channel 9 and the drawing shaft 10 is designed as a closed system. Here, a closed system means, in particular, that, apart from the supply of cooling air in the cooling device 3, no further air supply into the assembly takes place.

Preferably and in this embodiment, a diffuser 11 is attached to the drawing device 8 in the filament flow direction FS, through which the filaments 1 are guided. According to a preferred embodiment and in this exemplary embodiment, a secondary air inlet gap 12 is provided between the drawing device 8 or the drawing shaft 10 and the diffuser 11, which serves to introduce secondary air into the diffuser 11. Preferably and in this embodiment, the filaments are laid on a laying device configured to lay a sieve belt 13 after passing through the diffuser 11. The laid filament or nonwoven web 14 is then transported away or conveyed in the machine direction MD by means of the laid screen belt 13. Expediently and in this embodiment, a suction device for sucking air or process air through the laying device 13 is provided below the laying device or below the laying screen belt 13. Here, preferably and in this embodiment, a suction area 15 is provided below the laying sieve belt 13 below the diffuser outlet. Preferably, said suction area 15 extends at least over the width B of the diffuser outlet. Preferably and in this embodiment, the width B of the suction zone 15 is greater than the width B of the diffuser outlet.

According to a preferred embodiment and in this embodiment, each air supply chamber 5, 6 is divided into two chamber sections 16, 17, from which cooling air of different temperatures can be supplied in each case. In this embodiment, cooling air having a temperature T1 may be supplied from the upper chamber section 16, respectively, while cooling air having a temperature T2 different from the temperature T1 may be supplied from the two lower chamber sections 17, respectively.

according to a preferred embodiment and in this exemplary embodiment, a flow straightener 18 is provided in each air supply chamber 5, 6 on the cooling chamber side, which flow straightener extends preferably and in this exemplary embodiment over the two chamber sections 16, 17 of each air supply chamber 5, 6. The two flow straighteners 18 serve here to straighten the cooling air flow which encounters the thread 1. The flow straightener 18 will be described in further detail below.

According to the invention, at least one supply line 22 for supplying cooling air is connected to each air supply chamber 5, 6. The supply line 22 has a cross-sectional area QZ, which increases to the cross-sectional area QL of the air supply chamber 5, 6 at the transition of the cooling air into the air supply chamber 5, 6. The cross-sectional area QL is preferably at least three times and preferably at least four times as large as the cross-sectional area QZ of the supply line 22. Within the scope of the invention, the cross-sectional area QZ of the supply duct 22 is enlarged by a factor of 3 to 15 to become the cross-sectional area QL of the air supply chamber 5, 6.

Furthermore, within the scope of the invention, at least one planar homogenization element 23 is provided in each air supply chamber 5, 6, said homogenization element serving to homogenize the cooling air flow introduced into the air supply chamber 5, 6. Expediently, at least one planar homogenization element 23 is provided in each chamber section 17, 17 of the air supply chambers 5, 6. According to a particularly preferred embodiment, the homogenization element 23 is designed as a perforated element, in particular as a perforated plate 24 with a plurality of perforated openings 25 and/or as a homogenization screen 26 with a plurality or a plurality of mesh openings 27. According to a particularly preferred embodiment of the invention and in this exemplary embodiment, a plurality of homogenization elements 23 are arranged in each air supply chamber 5, 6 or in each chamber section 16, 17, respectively, at a distance from the flow straightener 18 in succession in the flow direction of the cooling air and at a distance from one another. Here, it is recommended and in this embodiment that the distance a1 between the flow straightener 18 and the homogenizing element 23 closest to the flow straightener 18 is at least 50mm, preferably at least 100 mm. The distance ax between the homogenization elements 23 arranged one after the other in the flow direction in the air supply chambers 5, 6 or in the chamber sections 16, 17 is likewise at least 50mm, preferably at least 100 mm.

according to the invention, the free flow area of the planar homogenizing element 23, or the area through which cooling air can freely flow, is 1% to 40%, preferably 2% to 35%, and preferably 2% to 30% of the total area of the planar homogenizing element 23. According to one embodiment, the free flow area of the planar homogenizing element 23 is 2% to 25%, expediently 2% to 20% and in particular 2% to 15%. Particularly preferably and in this exemplary embodiment, the free flow area of the homogenization elements 23 arranged one after the other, or the area through which cooling air can freely flow, increases from homogenization element 23 to homogenization element 23 toward the associated flow straightener 18 or toward the cooling chamber 4. Furthermore, expediently and in this exemplary embodiment, the area of the homogenizing element 23 extends over the entire cross-sectional area QL of the associated air supply chamber 5, 6 or of the associated chamber section 16, 17.

Fig. 3 and 4 each show a section through the air supply chamber 5. Instead of for the entire air supply chamber 5, 6, the illustration can also be for only one chamber section 16, 17 of the air supply chamber 5, 6. In the embodiment according to fig. 3, the cross-section QZ of the supply conduit 22 increases directly and without steps to the cross-sectional area QL of the air supply chamber 5. In the air supply chamber 5, four homogenizing elements 23 are arranged upstream of the flow rectifier 18 in the flow direction of the cooling air. The homogenizing element 23.0 is located in the transition region between the supply line 22 and the air supply chamber 5 in this exemplary embodiment and extends only over the cross section QZ of the supply line 22. Further homogenizing elements 23.1, 23.2 and 23.3 are each arranged in the air supply chamber 5 at a distance from one another and from the flow straightener 18. They extend over the entire cross-section QL of the air supply chamber 5. Typical parameters for the homogenizing elements 23.0 to 23.3 according to fig. 3 and for a respective device width of 1000mm (in the CD direction) are given by way of example in the following table. In the left column of the table, the vertical height h of the homogenizing elements 23 in mm is first listed, next to the right of which is the total area of each homogenizing element 23 and in the two columns next to the right, the free or freely cooling air-through flow area is given in percent and in mm 2. The relative free area is calculated by the following equation: the cross-sectional area of the homogenizing element x the flow area of the homogenizing element/the area of the outflow cross-section in the region of the rectifier. Thus, for the homogenizing elements 23.1, 23.2 and 23.3, the relatively free area (in percent) corresponds to the free flow area (in percent). Only for the homogenizing element 23.0 having a cross-sectional area corresponding to the supply duct 22 results in a relatively free area of only 1%. Said distance a (in mm) corresponds to the distance a of each single homogenizing element 23 from the flow straightener 18. When the relative free area of the homogenizing element 23 is plotted over the distance a of the homogenizing element 23 relative to the flow rectifier 18, the integral value in the last column corresponds to the integral below the curve.

sum of all: 49.6

The height H of the air supply chamber 5 according to fig. 3 may in this embodiment be 500mm and the length L of the air supply chamber 5 from the flow rectifier 18 up to the inlet of the supply duct 22 may be 1000 mm. According to a particularly preferred embodiment of the invention, the sum of the integral values specified above exceeds 45, preferably 50 and preferably 65.

fig. 4 shows a second embodiment of the air supply chamber 5 according to the invention. Four homogenizing elements 23.0 to 23.3 are also used here. In contrast to the exemplary embodiment according to fig. 3, however, the cross section QZ of the supply line 22 expands stepwise to the total cross-sectional area QL of the air supply chamber 5. Expediently, the stepped expansion in the square air supply chamber 5 is effected on all four walls toward the flow straightener 18. Apart from the difference due to the stepped cross-sectional expansion, the dimensions in the exemplary embodiment according to fig. 4 correspond in other respects to the dimensions in the exemplary embodiment according to fig. 3. The parameters for the embodiment of fig. 4 are listed in the following table analogously to the table relating to fig. 3:

sum of all: 47.4

fig. 5 shows the connection region of the curved supply line 22 to the air supply chamber 5. According to this embodiment, a sectional element 28 is provided in the feed conduit 22, which divides the feed conduit 22 into a plurality of individual conduit sections. An additional homogenization of the cooling air flow can be achieved on the basis of the segmentation or the installation of the vanes to the tube. In particular, the cooling air flow is subjected to a preliminary homogenization in this case and is therefore somewhat ready for a further homogenization or homogenization in the air supply chamber 5.

Fig. 6 shows a perspective view of a flow straightener 18, which is preferably used within the scope of the present invention. The flow straightener 18 serves to straighten the flow of cooling air that encounters the filaments 1. For this purpose, it is recommended and in this exemplary embodiment that each flow straightener 18 has a plurality of flow channels 19 oriented perpendicularly to the filament flow direction FS. The flow channels 19 are each delimited by channel walls 20 and are preferably designed in a straight line. According to a preferred embodiment and in the illustrated exemplary embodiment, the free-flowing flow area of each flow straightener 18 is greater than 90% of the total area of the flow straighteners 18. It has proven advantageous and in this embodiment the ratio of the length L of the flow channel 19 to the minimum inner diameter Di of the flow channel 19 is in the range between 1 and 10, suitably in the range between 1 and 9. The flow channels 19 of the flow straightener 18 may for example and in the embodiment of fig. 7 have a hexagonal or honeycomb-shaped cross section. The minimum internal diameter Di is measured between the opposite sides of the hexagon.

According to a preferred embodiment and in this exemplary embodiment, each flow straightener 18 has a flow screen 21 both on its cooling air inflow side ES and on its cooling air outflow side AS. Preferably and in this embodiment, two flow screens 21 per flow straightener 18 are provided directly upstream or downstream of the flow straightener 18. In this connection, the flow screen 21 should be distinguished from the homogenization element 23, which is configured as a homogenization screen 26. Preferably and in this embodiment, the two flow screens 21 of the flow straightener 18 or the surface of said flow screens 21 are oriented perpendicular to the longitudinal direction of the flow channel 19 of the flow straightener 18. It has been demonstrated that the flow screen 21 has a mesh width of 0.1mm to 0.5mm and preferably 0.1mm to 0.4mm and a wire thickness of 0.05mm to 0.35mm and preferably 0.05mm to 0.32 mm.