INSTALLATION AND METHOD FOR PRODUCING A FIBROUS MATERIAL WEB

Abstract

An installation for producing a fibrous material web, in particular a long-fiber paper or wet nonwoven web, contains a binder wire section having a binder wire for applying an aqueous binder to the fibrous material web, and a dryer section having a dryer fabric for drying and consolidating the fibrous material web. The binder wire section and the dryer section are arranged at a distance from each other, so that the fibrous material web is led from the binder wire to the dryer fabric in a free draw. At least one air extraction device is arranged at the edge of the installation in the region of the distance between the binder wire section and the dryer section.

Claims

1. An installation for producing a fibrous material web, comprising: a binder wire section having a binder wire for applying an aqueous binder to the fibrous material web; a dryer section having a dryer fabric for drying and consolidating the fibrous material web, wherein said binder wire section and said dryer section are disposed at a distance from each other, so that the fibrous material web is led from said binder wire to said dryer fabric in a free draw; and at least one air extraction device disposed at an edge of the installation in a region of a distance between said binder wire section and said dryer section.

2. The installation according to claim 1, wherein as viewed in a vertical direction, said at least one air extraction device is disposed substantially underneath the fibrous material web guided in the free draw, but not extending from the edge of the installation as far as under the fibrous material web guided in the free draw.

3. The installation according to claim 1, wherein said at least one air extraction device is a suction box.

4. The installation according to claim 1, wherein said at least one air extraction device is one of two extraction devices with one of said extraction devices disposed on a drive-side of the installation and another of said extraction devices disposed on an operator's-side of the installation.

5. The installation according to claim 4, wherein said extraction devices are configured such that a negative pressure originating from said extraction devices can be adjusted independently of each other.

6. The installation according to claim 1, wherein installation space underneath the fibrous material web guided in the free draw is kept free at least in a region between a last roller of said binder wire section, over which said binder wire is guided when said binder wire delivers the fibrous material web, and a first roller of said dryer section, over which said dryer fabric is guided when said dryer fabric picks up the fibrous material web.

7. The installation according to claim 1, wherein said binder wire runs at least in some sections horizontally or approximately horizontally and/or said binder wire section has at least one binder headbox.

8. The installation according to claim 1, further comprising a forming section for dewatering an aqueous suspension, which is placed upstream of said binder wire section in a processing direction of the fibrous material web through the installation.

9. The installation according to claim 8, further comprising a fibrous material suspension unit for producing the aqueous suspension for said forming section.

10. The installation according to claim 1, further comprising a winder for continuously winding up the fibrous material web onto winder cores to form wound rolls, wherein said winder is placed after said dryer section in the processing direction of the fibrous material web through the installation.

11. The installation according to claim 1, further comprising at least one blowing device for a non-contact floating guidance of the fibrous material web by means of air or another free-flowing medium is provided between said binder wire section and said dryer section, having a plurality of blowing zones that can be controlled/regulated independently of one another transversely to a running direction of the fibrous material web.

12. The installation according to claim 1, wherein the fibrous material web is a long-fiber paper or a wet nonwoven web.

13. The installation according to claim 8, wherein said forming section contains an inclined wire former, which has an inclined wire extending at an angle to a horizontal at least in some segments, and at least one single-layer headbox.

14. The installation according to claim 13, wherein said single-layer headbox is a multi-layer headbox.

15. The installation according to claim 11, wherein said at least one blowing device is a positionable blowing device.

16. A method for producing a fibrous web material, which comprises the steps of: providing an installation containing a binder wire section having a binder wire for applying an aqueous binder to the fibrous material web, and a dryer section having a dryer fabric for drying and consolidating the fibrous material web, wherein the binder wire section and the dryer section are disposed at a distance from each other, so that the fibrous material web is led from the binder wire to the dryer fabric in a free draw, the installation further having at least one air extraction device disposed at an edge of the installation in a region of a distance between the binder wire section and the dryer section; and during an intended operation of the installation air is extracted from the region between the binder wire section and the dryer section by means of the at least one edge-side air extraction device.

17. The method according to claim 16, wherein the fibrous material web is a wet-laid glass nonwoven web.

18. The method according to claim 16, which further comprises producing the fibrous material web at a speed of at least 170 m/min.

19. The method according to claim 16, wherein the fibrous material web has a weight per unit area of less than 30 g/m.sup.2.

20. The method according to claim 16, wherein the fibrous web material is a long-fiber paper or a wet-laid nonwoven web.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0029] FIG. 1 is a diagrammatic layout of an installation for producing a fibrous material web according to the prior art;

[0030] FIG. 2 is a diagrammatic, side view of a transfer region between a binder wire and dryer sections according to the prior art;

[0031] FIG. 3 is a diagrammatic, side view of the transfer region between the binder wire and dryer sections according to the invention of the instant application; and

[0032] FIG. 4 shows a schematic three-dimensional view of the transfer region between the binder wire and dryer sections according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0033] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a schematic layout of an installation 1 for producing a fibrous material web 2, in particular a long-fiber paper or wet-laid nonwoven web.

[0034] This installation 1 for producing the fibrous material web 2 contains a fibrous material suspension unit 3, a forming section 4, which has an inclined wire 5 running at an angle ? to the horizontal H, at least in some sections, and at least one at least one-layer, preferably multi-layer, headbox 6, a binder wire section 7, which has a binder wire 8 running at least in some segments horizontally or approximately horizontally, and at least one binder headbox 9, a dryer section 10 having a dryer fabric 11 and a winder 12 for continuously winding up the fibrous material web 2 onto winder cores 13 to form wound rolls 14.

[0035] In the fibrous material suspension unit 3, all the components needed to produce an aqueous suspension, such as water, cut fibers, binder and the like, are put into a first container (pulper) 15 provided with an agitator 16 and, after that, into a second container (pulper) 17 likewise provided with an agitator 18; the transport of the aqueous suspension is performed by the pumps 19, 20. The aqueous suspension can be, for example, a glass fiber slurry, which comprises glass fibers with a fiber length in the range from 6 to 40 mm, preferably from 8 to 30 mm, in particular from 10 to 25 mm, and so-called whitewater, and has a fiber concentration of about 0.2 to 1.0 percent by weight.

[0036] The fibrous material suspension unit 3 is followed by the next process stage, namely the dewatering of the aqueous suspension and the forming of the fibrous material web 2 with the aid of the inclined wire 5 arranged in the forming section 4. To this end, the aqueous suspension is applied to the inclined wire 5 by means of an at least single-layer, preferably multi-layer, headbox 6. The water filtered off out of the aqueous suspension underneath the inclined wire 5 is fed back in the circuit according to the arrow 21 and, for example, admixed with the aqueous suspension leaving the second container (pulper) 17 of the fibrous material suspension unit 3.

[0037] In the following process stage, at least one aqueous binder, such as an aqueous urea formaldehyde (UF) resin-based binder, is applied by means of a binder headbox 9 to the fibrous material web 2, which is still wet and resting on the binder wire 8 of the binder wire section 7. After that, the excess binder is also extracted in a known way in this binder wire section 7. The aqueous binder can also be applied to the still wet fibrous material web 2 in a manner not illustrated by using a curtain coater or a dip-and-squeeze applicator; however other application methods, such as spraying, are also suitable.

[0038] The next process stage is used for the drying and consolidation of the still wet fibrous material web 2 by means of curing (polymerization) of the binder, which bonds the glass fibers in the glass fiber nonwoven to one another. To this end, it is led through the dryer section 10 having the dryer fabric 11, which has two heated and illustrated continuous-flow ovens 22 or a drum or belt dryer, not illustrated. The fibrous material web 2 here is generally exposed to a temperature of 100? C. to 250? C. but for no longer than 1 to 2 minutes.

[0039] In a last process stage, the fibrous material web, having a mass per unit area range from 40 to 200 g/m.sup.2 and a binder proportion of 10 to 30%, is wound up in the winder 12 onto winder cores 14 to form wound rolls 13, in order then to be able to be supplied to following conversion or processing stations.

[0040] Between the binder wire section 7 and the dryer section 10, an adjustable blowing device (not illustrated) for the non-contact floating guidance of the fibrous material web 2 by means of air or another free-flowing medium can further be provided, having a plurality of blowing zones that can be controlled/regulated independently of one another transversely to the running direction of the fibrous material web 2.

[0041] FIG. 2 shows the transfer region 24 between the binder wire section 7 and the dryer section 10 in a schematic side view, and also the problem of the formation of creases F in the prior art. The fibrous material web 2 is transported on the binder wire 8 as far as a last roller 25 of the binder wire section 7, then guided in a free draw as far as a first roller 26 of the following dryer section 10, where it is picked up by the dryer fabric 11 and transported onward. The arrows with the filled tips illustrate here the flows of the air which is entrained by the binder wire 8 of the fibrous material web 2 and the dryer fabric 11 on their surfaces. As a result of these airflows, turbulences occur in the interspace between the two rolls 25 and 26, which have a detrimental effect on the fibrous material web 2 guided in the free draw. In particular, shortly before the fibrous material web 2 is guided onto the dryer fabric 11, it tends to form creases F. This creasing is critical for the further conversion process of the fibrous material web 2 and can even lead to the breakage of the fibrous material web 2.

[0042] FIG. 3 shows substantially the same schematic side view of the transfer region 24 as FIG. 2 but with the solution according to the invention, which prevents the creasing of the fibrous material web 2. A substantial constituent part of this solution is an air extraction device 27, which is arranged in the transfer region 24 underneath the fibrous material web 2 in the vertical direction but at the edge of the fibrous material web 2 guided in the free draw. In other words, the air extraction device 27 is not located directly under the fibrous material web 2 but is arranged offset laterally relative to the latter in the machine transverse direction (direction orthogonal to the image plane of FIG. 2). The air extraction device 27 has an opening area 28 (cf. FIG. 4) which is directed toward the free interspace between the two rolls 25 and 26 in order to extract air from this interspace and then to carry it away deliberately (cf. arrow downward from the air extraction device 27). In this way, turbulences in the transfer region 24 between the two rolls 25 and 26 can largely be avoided, so that the fibrous material web 2 has no danger of forming creases F. At the same time, as a result of its edge-side arrangement relative to the still unbonded fibrous material web 2, the air extraction device 27 is largely protected from contaminants from the latter.

[0043] Preferably, the installation 1 according to the invention has such an air extraction device 27 respectively both on its operator's side and on its drive side, as illustrated schematically in FIG. 4. In the three-dimensional illustration of FIG. 4, for reasons of clarity, only the first roller 26 of the dryer section 10, part of the dryer fabric 11, which is moved in the direction of the arrow, and the two edge-side air extraction devices 27 are shown here. The aforementioned opening area 28 can be seen in one of these two air extraction devices 27. The two air extraction devices 27 are configured as suction boxes here.

[0044] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention.

LIST OF DESIGNATIONS

[0045] 1 Installation [0046] 2 Fibrous material web [0047] 3 Fibrous material suspension unit [0048] 4 Forming section [0049] 5 Inclined wire [0050] 6 Headbox [0051] 7 Binder wire section [0052] 8 Binder wire [0053] 9 Binder headbox [0054] 10 Dryer section [0055] 11 Dryer fabric [0056] 12 Winder [0057] 13 Winder core [0058] 14 Wound roll [0059] 15 First container (Pulper) [0060] 16 Agitator [0061] 17 Second container (Pulper) [0062] 18 Agitator [0063] 19, 20 Pumps [0064] 21 Feedback circuit [0065] 22 Continuous-flow oven [0066] 24 Transfer region [0067] 25 Last roll of the binder wire section [0068] 26 First roll of the dryer section [0069] 27 Air extraction device [0070] 28 Opening area [0071] ? Angle [0072] F Crease [0073] H Horizontal