EP2912222B1 - Device for producing a spun-bonded fleece - Google Patents

Description

The invention relates to a device for producing a spunbonded nonwoven made of synthetic filaments according to the preamble of claim 1.

For the production of spunbonded nonwovens, it is generally known that a plurality of freshly extruded synthetic filaments after melt spinning and cooling are withdrawn together as a filament curtain, stretched and deposited on a storage belt to form a nonwoven fabric. The deposited filaments as well as the fiber formation within the spunbonded web produced by the filaments determine the physical properties of the spunbonded web. In that regard, the individual process steps for spinning, cooling, stretching and depositing the fibers must be particularly matched to one another in order to produce the spunbonded fabric with the desired properties continuously.

So goes out of the DE 195 21 466 A1 a device in which the filaments between a spinning device and a storage device is guided by a more or less closed shaft system. Thus, the cooling device provided underneath the spinning device has a cooling shaft which opens with its end in a process shaft. The process shaft is assigned a diffuser at the end facing a storage belt. To guide the filaments, a cooling air, which is passed to cool the filaments in the cooling shaft in the cooling shaft, and in the process shaft, a process air, which is used essentially for stretching and for depositing the filaments used. to Influencing the air-fiber flow additional connections are provided in the process shaft to initiate or remove auxiliary air flows as required in the process shaft. However, such auxiliary air streams basically have the disadvantage that only an air-fiber flow optimized in front of the tray can be produced. The air-fiber flows generated for the cooling of the filaments and for stretching the filaments remain unaffected.

In principle, however, devices are also known in the prior art, in which the stripping and stretching of the filaments takes place independently of the cooling by a draw-off nozzle. Such a device is for example from the DE 40 14 414 A1 known. In this case, a throttle element is formed between the cooling device and the drafting device in order to obtain a separation between the cooling air duct and the process air duct. In order to avoid turbulence of the air at the throttle cross section, the cooling air is passed across the filament curtain. Therefore, the discharge nozzle provided below the cooling device generates an intensive injection flow in the process shaft, in order to ensure a deduction of the filaments from the spinning device by appropriate suction action on the inlet side of the discharge nozzle. An adjustability of the process air for drawing and guiding the filaments is therefore possible only to a very limited extent. Thus, in the case of an insufficient process air flow, a lack of suction on the inlet side occurs, which jeopardizes the inlet of the filament bundle.

It is therefore an object of the invention to provide a generic device of the type mentioned in such a way that an individual Adjustability of the air ducts in the shaft system for handling and guiding the filaments is possible.

This object is achieved in that between a filament outlet of the cooling shaft and a filament inlet of the process shaft, a short free travel is formed, in which the cooling air is discharged in an environment. Here, the cooling air is guided in the cooling shaft in the direction of filaments and occurs together with the filaments at a filament outlet of the cooling shaft out of the cooling shaft.

Advantageous developments of the invention are defined by the features and feature combinations of the respective subclaims.

The invention was not suggested by the fact that from the WO 2000/065133 a device for producing a spunbonded fabric is known, in which the drafting device is arranged at a distance below a cooling device. Here too, the drawing device has a draw-off nozzle which is operated with a compressed-air flow in order to generate a suction effect on the inlet side on the one hand and to generate an intensive air-fiber flow for drawing off the filaments on the other hand. A leadership of the filaments with relatively low air flow and low pressure conditions within a shaft system is not possible with the known device. Comparable devices that are designed with a discharge nozzle and provide a so-called Saugverstreckung are also from the US 3,929,542 A and the EP 0 674 036 A2 known.

The invention has the particular advantage that the cooling air and the process air can be set independently of each other to the respective filament type. The entrainment of the cooling air from the cooling shaft into the process shaft is advantageously substantially avoided by a short free travel, in which an exchange with the ambient air can take place. It is essential that the cooling air inside the cooling shaft is guided as possible in the direction of filaments, so that a supporting conveying effect in addition to the cooling begins. Thus, the filament curtain can be safely introduced into the process shaft in which the injected process air generates a tensile force on the filaments required for drawing the filaments. The process air is supplied separately to the process shaft. The relatively low air velocity within the process well also favors the deposition of the fibers, wherein the diffuser of the laying device leads to a widening of the filament curtain and corresponding distribution of the filaments for spunbonding.

In order to obtain an unimpeded exchange of the cooling air with respect to the environment, the development of the device according to the invention is preferably carried out, in which the free path is formed by a distance between the filament outlet of the cooling shaft and the filament inlet of the process shaft. In this case, the outlet cross section of the filament outlet and the inlet cross section of the filament inlet can be matched to one another such that an unhindered transition of the filament bundle without the formation of air turbulences is possible.

The distance between the filament outlet of the cooling shaft and the filament inlet of the process shaft is designed according to the titre of the filaments and volume flow of the cooling air flow with a size in the range of 10 mm to 500 mm.

The avoidance of air turbulence during the transition from the cooling shaft into the free path and from the free path into the process shaft can advantageously be further improved by several adjustable air baffles are provided, which extend laterally along a width of the cooling shaft and / or the process shaft.

So that a cooling air flow acting in the running direction of the filaments arises within the cooling shaft, according to an advantageous development of the invention, the cooling shaft is arranged at least with a section facing the spinning device with air-permeable shaft walls between two opposing blowing chambers, through which the cooling air can be injected from both sides in the cooling shaft , Thus, the filaments on both sides of the spinning device can be uniformly cooled by a cooling air flow.

The drawing of the filaments can likewise be carried out particularly uniformly in that an inlet region of the process shaft with air-permeable shaft walls extends between two opposite air ducts through which the process air can be injected in the process shaft. Thus, the filament curtain can be evenly stretched within the process shaft.

The air flow of the process air during injection into the process shaft can be advantageously further improved by having the process shaft for connecting the air ducts opposite air inlet openings with a plurality of air guide elements.

In particular lamellar baffles, which are arranged one above the other and have an adjustable design, have proven to be suitable as air-guiding elements. Thus, the process air can be blown over the entire width of the process shaft in a predetermined flow direction. In order to reduce the air losses as possible despite the separate generation and supply of the cooling air and the process air, the development of the invention is particularly advantageous, in which the air ducts are coupled to a fan which is connected via a suction connection with a suction chamber of the storage device. Thus, the process air used for stretching and depositing the filaments can be used continuously.

For this purpose, the suction chamber is advantageously arranged with a suction opening below a depositing belt of the depositing device, the suction opening of the suction chamber being associated with a diffuser outlet of the diffuser assigned to the depositing belt opposite the side.

In order to additionally influence the depositing of the filaments on the depositing belt independently of the process air, the development of the invention is particularly advantageous, in which at least one air inlet slot is formed in a transition region between the process shaft and the diffuser, through which air inlet slot an additional process air to the diffuser can be fed. Thus, additional storage effects within the diffuser can be generated independently of the process air. The additional process air could be generated by a suction effect from the environment or actively by a blower.

The device according to the invention for producing a spunbonded non-woven fabric is described in more detail below with reference to some embodiments with reference to the accompanying figures.

Fig. 1

schematisch eine Querschnittsansicht eines ersten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung

Fig. 2

schematisch eine Querschnittsansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Vorrichtung

Fig. 3

schematisch eine Querschnittsansicht eines Ausführungsbeispiels einer Spinneinrichtung

Fig. 4

schematisch eine Querschnittsansicht eines Ausführungsbeispiels einer Ablageeinrichtung

They show:

Fig. 1

schematically a cross-sectional view of a first embodiment of the device according to the invention

Fig. 2

schematically a cross-sectional view of another embodiment of the device according to the invention

Fig. 3

schematically a cross-sectional view of an embodiment of a spinning device

Fig. 4

schematically a cross-sectional view of an embodiment of a storage device

In the Fig. 1 a cross-sectional view of a first embodiment of the device according to the invention is shown. The device is formed from a spinning device 1, a cooling device 2, a stretching device 3, a laying device 4 and a storage device 5. The devices 1 to 5 are arranged vertically one above the other and cooperate to produce a spunbond of synthetic filaments.

For extruding the filaments, the spinning device 1 has a spinneret 7, which is held on an underside of a spinneret 6. The spinneret 7 extends over a working width which is perpendicular to the plane of the drawing. On the underside, the spinneret 7 has a nozzle plate with a plurality of nozzle openings, which are formed in a row-shaped arrangement. The spinneret 7 is coupled to one or more spinning pumps, the polymer melt under pressure of Spinneret 7 feeds. The design and arrangement of the spinning pump is not shown here.

Directly below the spinning device 1, the cooling device 2 is provided which has a cooling shaft 8. The cooling shaft 8 is arranged with a spinneret 7 facing portion between two blast chamber 10.1 and 10.2. The chamber walls 9.1 and 9.2 associated with the blast chamber 10.1 and 10.2 are permeable to air and designed as blast walls. The blow chambers 10.1 and 10.2 are coupled to an air conditioning unit, not shown here, to blow a cooling air over the blowing walls 9.1 and 9.2 in the cooling shaft 8.

In a section of the cooling shaft 8 below the blast chamber 10.1 and 10.2, a filament outlet 11 is formed on the cooling shaft 8. The filament outlet 11 of the cooling shaft 8 is assigned a filament inlet 15 of a process shaft 16 at a short distance. The process shaft 16 is part of the drafting device 3. Here, the process shaft 16 to the upper region below the filament inlet 15 opposite air-permeable shaft walls 19.1 and 19.2. The air-permeable shaft walls 19.1 and 19.2 are each associated with an air shaft 18.1 and 18.2 on both sides. The air shafts 18.1 and 18.2 are coupled to an air source, not shown here, to initiate a process air via air ducts 18.1 and 18.2 in the process shaft 16.

In the in Fig. 1 illustrated embodiment, the air-permeable shaft walls 19.1 and 19.2 by a plurality of air inlet openings Air guide elements 20.1 and 20.2 formed. The air guide elements 20.1 and 20.2 are held one above the other in this example as lamellar baffles extending in parallel over the entire working width. The air baffles are designed to be adjustable, so that the process air over the entire width of the shaft walls of the process shaft 16 can be injected uniformly.

The end of the process shaft 16 opens into a diffuser 21 of the laying device 4. Between the process shaft 16 and the diffuser 21 are opposite to both longitudinal sides air inlet slots 22.1 and 22.2 formed, through which an additional process air can be introduced. The air inlet slots 22.1 and 22.2 extend over the longitudinal sides of the shaft walls of the process shaft 16 and the diffuser 21, so that the filament curtain 14 is uniformly monitored on both sides with an additional process air. The diffuser 21 is formed by inclined shaft walls which form a widened diffuser outlet 22 at the end. The diffuser outlet 22 ends immediately in front of a storage belt 23 of the storage device 5.

The storage belt 23 of the storage device 5 is formed permeable to air and is continuously driven by a tape roll 24. The running direction of the storage belt 23 is indicated by an arrow in Fig. 1 characterized. The diffuser 21 are each associated with a seal roller pair 29 and a Kompaktionswalzenpaar 28 on both sides, which lead opposite the storage belt 23 in a nip.

On the opposite side of the storage belt 23 to the diffuser outlet 22, the storage device 5 has a suction chamber 25, which is connected via a suction connection to a vacuum source, not shown here.

In operation, a plurality of individual filaments are extruded through the spinning device 1, which enter the cooling shaft 8 of the cooling device 2. To solidify the filaments 14, a cooling air is blown into the cooling shaft 8 from the sides of the filaments 14 by the blast chambers 10.1 and 10.2. The cooling air is guided in the running direction of the filaments 14 and, together with the filaments at the filament outlet 11, emerges from the cooling shaft 8. The filaments 14 pass through a short free path 13 and are continuously absorbed and withdrawn from the process shaft 16 and the process air injected therein. The cooling air occurs in the area of the free path 13 in the environment. The removal of the cooling air from the filament curtain is thereby further assisted by the filament inlet 15 of the process shaft 16 on both sides Luftabstreifbleche 17 are arranged. Thus, a substantial portion of the cooling air is separated and not introduced into the process shaft 16.

The leadership of the filaments and the stretching of the filaments is thus determined essentially by the process air, which is supplied via the air ducts 18.1 and 18.2 on both sides of the process shaft 16. For this purpose, the air-permeable shaft walls 19.1 and 19.2 in the air ducts 18.1 and 18.2 are designed with adjustable air-conducting elements 20.1 and 20.2 in order to blow in the process air in the direction of filaments to be able to. The air guide elements 20.1 and 20.2 are preferably formed by lamellar air baffles, which are designed to be adjustable.

The air filament stream formed by the process air is subsequently taken up by the diffuser 21 of the laying device 4 and deposited to form a spunbonded nonwoven on the surface of the depositing belt 23. In order to support and distribute the filament deposit, additional process air streams can be injected on both sides of the filament curtain via the opposing air inlet slots 22.1 and 22.2. These auxiliary air streams can advantageously produce additional effects within the diffuser that affect the formations of the filaments when deposited into a spunbonded web.

At the in Fig. 1 illustrated embodiment of the device according to the invention, an exchange between the cooling air and the environment takes place directly in the formed between the cooling shaft 8 and the process shaft 16 free run 13. It has been found that, depending on the filament titer and cooling air volume flow, a distance is formed between the filament outlet 11 on the cooling shaft 8 and the filament inlet 15 on the process shaft 16. The distance is in Fig. 1 marked with the reference symbol A. The distance A can be a size in the range of 10 mm to max. 500 mm. For instance, very intensive cooling air flows are enough for very short distances in order to obtain an exchange of the cooling air of the environment. At low cooling air flows, a longer free travel is preferably needed to obtain an exchange with the environment.

In Fig. 2 a further embodiment of a device according to the invention for producing a spunbonded fabric of synthetic filaments is shown. The embodiment is in Fig. 2 also shown in a cross-sectional view, wherein the structure is substantially identical to the embodiment of FIG Fig. 1 is. In that regard, reference is made below to the above description and otherwise only the differences explained below.

At the in Fig. 2 illustrated embodiment of the spinning device according to the invention the filament outlet 11 of the cooling shaft 8 are each associated with adjustable baffles 12, which may affect the cross section of the filament outlet 11 and thus the cooling air filament current.

Another essential difference in the embodiment according to Fig. 2 is given by the supply of process air through the air ducts 18.1 and 18.2. As from the illustration in Fig. 2 shows, the air ducts 18.1 and 18.2 are coupled to the blower 27, which is connected via the suction port 26 to the suction chamber 25 of the storage device 5. In that regard, the process air is taken up continuously after filing the filaments to the spunbonded 30 of the suction chamber 25 and returned via the fan 27 and the air ducts 18.1 and 18.2 the process shaft.

The function of in Fig. 2 illustrated embodiment is identical to the embodiment according to Fig. 1 so that reference is made to the aforementioned description. The storage area at the storage device 4 shows in the embodiment Fig. 2 however, no sealing rolls on.

Air flow of the process air supplied via the air inlet slots 22.1 and 22.2 can advantageously be generated from the environment. Basically, however, there is also the possibility that in the embodiment shown Fig. 1 and 2 an additional air source is coupled to one or both of the air inlet slots for blowing in the additional process air.

When extruding some polymer materials, it is known that volatiles such as monomers or oligomers occur directly at the bottom of the spinneret due to extrusion of the polymer material. Such volatile components are preferably kept out of the cooling device in order to avoid contamination by condensation. In Fig. 3 an embodiment of a spinning device 1 is shown, as for example, alternatively in the embodiments according to Fig. 1 or 2 could be used. Fig. 3 schematically shows a cross-sectional view of the spinning device.

The spinning device 1 has a spinning beam 6, on its underside a spinneret 7 with a variety not shown here nozzle openings. The nozzle openings may in this case be formed distributed in rows or spirally or in any other arrangement on the surface of the spinneret.

Below the spinning device 1, the cooling device 2 is provided, which forms a cooling shaft 8 below the spinneret 7. On the underside of the spinning device 1, a suction channel 31.1 and 31.2 is formed between the spinning beam 6 and the cooling shaft 8 on both sides of the spinneret 7. The suction channels 31.1 and 31.2 are coupled to a suction device 32, by which a suction flow is generated. This allows a loaded hot air directly from the lower environment of the spinneret 7 record and dissipate.

The cooling device 2 is according to the embodiment according to Fig. 1 executed and has two opposite blow chambers 10.1 and 10.2, which are connected via blower walls 9.1 and 9.2 with the cooling shaft 8. In that regard, to the above description to the Fig. 1 Referenced.
This in Fig. 3 illustrated embodiment of the spinning device 1 is so far particularly suitable to dissipate volatile components directly after the extrusion of the polymer material from the spinning process.

To the storage function of the embodiments according to Fig. 1 and 2 to improve is in Fig. 4 a further embodiment of a storage device 5 schematically shown in a cross-sectional view. At the in Fig. 4 illustrated embodiment, the suction chamber 25 below the storage belt 23 a plurality of suction zones 33.1 and 33.2. A first suction zone 33. 1 is arranged directly opposite the diffuser outlet 22 of the diffuser 21. In this area, the suction chamber 25 is kept open relative to the storage belt 23 or as shown here is shielded by a coarse perforated plate 34.1. The suction zone 33.1 forms the storage area in which the process air is sucked off and the fleece is fixed on the storage belt 23. In an area of the storage belt 23 assigned to the compact roller pair 28 in the direction of travel of the strip, the suction chamber 25 forms a further suction zone 33.2. In this suction zone 33.2, the suction chamber 25 is shielded from the depositing belt 23 by a fine perforated plate 34.2. In this area, the web guided on the depositing belt 23 is to be fixed only for transfer up to the compact roller pair 28. Excessively high suction power is critical in this zone, since the peripheral areas of the fleece deposit could be disturbed due to incoming ambient air. In that regard, a lower suction in the suction zone 33.2 is observed.

In order to be able to produce a multilayered nonwoven, it is known that a plurality of spinning bars are arranged one behind the other in the direction of the strip, so that a laid fleece must already be supplied to the depositing area of the adjacent spinning bar. For such feeds, the in Fig. 4 illustrated storage device 5 advantageously extend such that the suction chamber 25 is supplemented by a third suction zone 33.3. The suction zone 33.3 forms the inlet into the storage area and is upstream of the diffuser 21 in the strip direction. In the suction zone 33.3, an additional suction flow can be generated, which ensures a fixation of the incoming fleece in a multi-beam system. Thus, a lower fleece can be evenly fed to the storage area.

This in Fig. 4 illustrated embodiment could thus also in the embodiments of the device according to the invention Fig. 1 and 2 be used.

LIST OF REFERENCE NUMBERS

1

spinner

2

cooling device

3

drawing device

4

securing device

5

Bin Setup

6

spinning beam

7

spinneret

8th

cooling shaft

9.1, 9.2

Blaswände

10.1, 10.2

blowing chambers

11

filaments outlet

12

Air baffle

13

free-range

14

Filament curtain, filaments

15

a filaments

16

process shaft

17

Luftabstreifblech

18.1

airshaft

18.2

airshaft

19.1, 19.2

air-permeable shaft wall

20.1, 20.2

air guide elements

21

diffuser

22.1, 22.2

Air inlets

22

diffuser outlet

23

depositing belt

24

tape roll

25

suction chamber

26

suction

27

fan

28

Compact roller pair

29

Sealing roller pair

30

spunbond

31.1, 31.2

suction

32

suction

33.1, 33.2, 33.3

suction zones

34.1, 34.2

perforated sheet

Claims (11)

1. Device for the production of a spun-bonded non-woven fabric (30) from synthetic filaments (14), having a spinning installation (1), having a cooling installation (2), having a drawing installation (3), having a laying installation (4), and having a depositing installation (5), wherein a cooling shaft (8) of the cooling installation (2), a processing shaft (16) of the drawing installation (3), and a diffusor (21) of the laying installation (4) interact for guiding the filaments (14), and wherein cooling air to the cooling shaft (8) and processing air to the processing shaft (16) are infed separately,
   characterized in that
   the cooling air in the cooling shaft (8) is conjointly guided in the running direction of the filaments (14) and exits from the cooling shaft (8) collectively with the filaments (14) at a filament outlet (11) of the cooling shaft (8), wherein a short free section (13) in which the cooling air is dischargeable into an environment is configured between the filament outlet (11) of the cooling shaft (8) and a filament inlet (15) of the processing shaft (16).
2. Device according to Claim 1,
   characterized in that
   the free section (13) is formed by a spacing (A) between the filament outlet (11) of the cooling shaft (8) and the filament inlet (15) of the processing shaft (16).
3. Device according to Claim 2,
   characterized in that
   the spacing (A) between the filament outlet (11) of the cooling shaft (8) and the filament inlet (15) of the processing shaft (16) has a size in the range from 10 mm to 500 mm.
4. Device according to one of Claims 1 to 3, characterized in that the filament outlet (11) of the cooling shaft (8) and/or the filament inlet (15) of the processing shaft (16) are/is assigned a plurality of adjustable air baffle plates (12, 17) which extend laterally along a width of the cooling shaft (8) and/or of the processing shaft (16).
5. Device according to one of Claims 1 to 4, characterized in that the cooling shaft (8), at least by way of a portion that faces the spinning installation (1) and that has air-permeable shaft walls (9.1, 9.2), is disposed between two mutually opposite blower chambers (10.1, 10.2) through which the cooling air is capable of being blown into the cooling shaft (8).
6. Device according to one of Claims 1 to 5, characterized in that an entry region of the processing shaft (16) that has air-permeable shaft walls (19.1, 19.2) extends between two mutually opposite air shafts (18.1, 18.2) through which the processing air is capable of being blown into the processing shaft (16).
7. Device according to Claim 6,
   characterized in that
   the processing shaft (16) for linkage to the air shafts (18.1, 18.2) has mutually opposite air-inlet openings having a plurality of air-directing elements (20.1, 20.2).
8. Device according to Claim 7,
   characterized in that
   the air-directing elements (20.1, 20.2) of one of the shaft walls (9.1, 9.2) are disposed on top of one another as lamella-shaped baffle plates and are configured so as to be adjustable.
9. Device according to one of Claims 6 to 8, characterized in that the air shafts (18.1, 18.2) are coupled to a fan (27), and in that the fan (27) is connected to a suction chamber (25) of the depositing installation (5) by way of a vacuum connector (26).
10. Device according to Claim 9,
    characterized in that
    the suction chamber (25) having a suction opening is disposed below a depositing belt (23) of the depositing installation (5), wherein the suction opening of the suction chamber (25) is assigned to a diffusor outlet (22) of the diffusor (21) that is assigned to the depositing belt (23) on the opposite side of the belt.
11. Device according to one of Claims 1 to 10, characterized in that at least one air-inlet slot (22.1, 22.2) through which additional processing air is infeedable to the diffusor (21) is configured in a transition region between the processing shaft (16) and the diffusor (21).

Images