EP2228489B1 - Device and method for manufacturing a multi-layer fibrous sheet - Google Patents

Description

The invention relates to a method and an apparatus for producing multilayer fiber web according to the features of the preambles of independent claims 1 and 5.

STATE OF THE ART

The present invention relates to the production of a multilayer fibrous web, in particular in the paper or cardboard area. Usually, a first and a second layer formed in a Vergautschzone be vergautscht together, in which they are fed through a respective sieve a Vergautschelement around which the second layer feeding second sieve is guided. This second wire runs on the Vergautschelement before the carried by him second layer comes into contact with the first layer. Here, for example, sees the EP 1 811 082 A1 at least one layer before its reaching the Vergautschzone at least slightly superheated steam is applied so as to effect a most extensive, preferably complete displacement of air from the Vergautschzone. The superheated steam is output from a preferably web-wide steam blower.

Also the WO 92/05310 discloses a method and an apparatus for producing multilayer coatings in which steam or water is introduced as a bonding agent between the layers.

Furthermore, the disclosed WO97 / 37838 A1 a method and an apparatus for producing multilayer fibrous webs, wherein an adhesive, for example starch, is applied for joining the layers.

Furthermore, the disclosed EP 1 388 608 A2 a wire section for producing a multilayer fibrous web. It is applied to one of the layers, before merging the layers of a glue sump in the inlet gusset.

TASK

The object of the invention is to increase the strength of the base paper and the subsequent end product.

SOLUTION OF THE TASK

To achieve the object, the features of the independent claims 1 and 5.

At least one layer is wetted with a medium before being juxtaposed with the other layer.

This has the advantage that by wetting with a medium which penetrates deeply into the single paper layer, the paper layer is already solidified in itself and later adhesives can diffuse better into the situation. As a result, a known cleavage is avoided, the paper layer is solidified in itself. The situation has on reaching the wetting device still has a water content of about 50%. As the wetting medium contains starch, the starch grain swells and lays between the fibers and connects them.

In an advantageous embodiment, the medium to be atomized is atomized by means of a second medium. This has the advantage that the suspension controlled by the second medium is atomized controlled and the degree of atomization is precisely adjustable.

This way of applying the medium has the advantage that the medium can have a much higher solids content.

In a preferred embodiment, the atomization of the liquid medium takes place via a control of the flow rate at a corresponding spraying device and / or the pressure control of a second medium, for example compressed air, in order to achieve the desired atomization degree of the suspension.

To achieve the object also leads a device in which at least one wetting device is provided.

In a preferred embodiment, the wetting device is a spray bar, which is arranged in front of a so-called Vergautschungsvorrichtung in which two layers of base paper are stacked. By the wetting of the layers with the suspension of water and starch before Vergautschen raw paper is achieved with a greater strength. In addition, dewatering substantially removes the liquid supplied by wetting.

In a preferred embodiment, the wetting device has a spray bar on which a number of spray devices are provided, with which the suspension can be atomized, so that a sufficient areal and uniform atomization or wetting of the individual layers with the suspension can take place.

DESCRIPTION OF THE FIGURES

• Figur 1 eine schematische Ansicht der Anordnung einer erfindungsgemässe Benetzungseinrichtung vor einem Vergautschungsabschnitt einer Rohpapieranlage,
• Figur 2 eine Vorderansicht einer erfindungsgemässen Benetzungseinrichtung und
• Figur 3 eine Draufsicht der erfindungsgemässen Benetzungseinrichtung in Figur 2.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment, and with reference to the drawing; this shows in

• FIG. 1 a schematic view of the arrangement of a wetting device according to the invention in front of a Vergautschungsabschnitt a raw paper plant,
• FIG. 2 a front view of a wetting device according to the invention and
• FIG. 3 a plan view of the inventive wetting device in FIG. 2 ,

In FIG. 1 the arrangement of a wetting device P according to the invention in a raw paper production plant is shown schematically. A first paper ply 34 is fed to a second paper ply 35, each made of raw paper, to a scarfing element 40 for applying the first paper ply 34 to the second paper ply 35.

Before the Vergautschelement 40 an inventive wetting device P is arranged. With the wetting device P, a suspension is sprayed as a spray 38 on the first and the second paper layer 34, 35, which penetrates into the paper layers.

The wetting device P can have two spray bars 1, 1 'according to the invention or else only one spray bar 1 or 1', in which case only one of the paper layers 34, 35 is wetted.

In FIGS. 2 and 3 the inventive wetting device P is shown with a spray bar 1 having a number of fasteners 2, wherein a spray device 3 is attached to each fastener 2. About the individual sprayers 3, a first medium to be atomized, which is a suspension of water and starch, is atomized by means of a second medium.

The fasteners 2 have several functions. At the fasteners 2, the respective sprayers 3 are releasably attached. Furthermore, discrete lines (not shown) are provided in the fastening elements 2, by means of which the media for spraying and atomizing and for controlling the spraying device 3 are supplied or forwarded to the next fastening element 2.

A connection element 12 attached to the one end section of the spray bar 1 has in its peripheral sides a plurality of connections 13-15 for supplying the first and second medium and a connection for discharging the excess first medium. The connection element 12 has in its front side a spray medium inlet connection 13 and a control medium inlet connection 14, in its upper side (FIG. FIG. 2 ) has a sputtering media inlet port 15 and a spray medium drain port in its backside (not shown). A closure member 4 attached to the other end portion closes off the discrete conduits or returns excess spray medium back to the spray medium drain port.

The functioning of the wetting apparatus according to the invention is the following:

The spray bar 1 according to the invention, via the connecting element 12, the necessary media, such as spray medium (suspension), control medium (for controlling the spray 3) and the sputtering medium (compressed gas for atomizing the spray medium), via the corresponding terminals 13 - 15 via discrete supply lines (not shown) fed. The connecting element 12 directs the pressurized media in its and formed in the fasteners 2 discrete lines to the individual sprayers 3, which spray or nebulise the suspension on the paper layers accordingly. <B> LIST OF REFERENCES </ b> 1, 1 ' spray 34 paper layer 67 2 fastener 35 paper layer 68 3 spraying 36 Vergautschungseinrichtung 69 4 closure element 37 70 5 38 spray 71 6 39 feed 72 7 40 Vergautschelement 73 8th 41 74 9 42 75 10 43 76 11 44 77 12 connecting element 45 78 13 Spray medium inlet port 46 79 14 Control medium inlet port 47 15 Atomizing inlet port 48 16 49 17 50 18 51 19 Control medium port 52 20 Atomizing port 53 21 Spray medium connection 54 P Wetting device 22 55 23 56 24 57 25 58 26 59 27 60 28 61 29 62 30 63 31 64 32 65 33 66

Claims (8)

1. A method for producing multi-ply fibre web, in particular multi-ply base paper, in which at least two layers of paper (34, 35) are pressed against each other and at least one layer (34, 35), before being laid against the other layer, is wetted with a first medium by means of a wetting means (P), which medium is a suspension consisting of a liquid/starch mixture, characterised in that the at least one layer, upon reaching the wetting means, still has a water content of approximately 50%.
2. A method according to Claim 1, characterised in that the first medium, for wetting, is atomised or nebulised by means of a second medium.
3. A method according to Claim 2, characterised in that the degree of atomisation of the first medium is controlled by means of the throughput rate thereof and/or the pressure in the second medium.
4. A method according to Claim 2 or 3, characterised in that the second medium is a propellant, in particular a gas.
5. A device for producing multi-ply fibre web, in particular multi-ply base paper, in which at least two layers of paper (34, 35) are laid against each other, with a wetting means (P, P') being associated with at least one layer (34, 35), which means is suitable for wetting the at least one layer with a first medium, and is arranged before a couching means (36) for laying individual paper layers (34, 35) one on another, the first medium being a suspension consisting of a liquid/starch mixture, characterised in that the at least one layer, upon reaching the wetting means, still has a water content of approximately 50%.
6. A device according to Claim 5, characterised in that the wetting means (P, P') has at least one spraying means (3).
7. A device according to Claim 6, characterised in that the spraying means (3) is arranged on a spraying bar (1, 1').
8. A device according to Claim 6 or 7, characterised in that the spraying means (3) has at least a connection (13) for connecting the spraying means (3) to the first medium and a connection (14, 15) for connecting the spraying means (3) to a second medium,

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