DE19747301A1 - Paper machine's sheet forming system giving wider range of products - Google Patents

Abstract

A sheet forming system in a paper or cardboard machine has at least one multilayer head box (10) where at least one layer next the wire cloth has a connection with the machine's wire cloth water circulation (15, 16) so that it is propelled exclusively by water or wire cloth water.

Description

The invention relates to a sheet formation system according to the preamble of claim 1 and the Using a multi-layer headbox according to the preamble of claim 2.

From the patent application DE 44 40 079 by the applicant is a sheet formation system with a two-layer Headbox with an internal lamella Generation of a two-layer fibrous web known. From DE 44 15 053 the applicant is a three-layer headbox with fins Generation of a three-layer paper web is known.

Both of the above headboxes serve one Paper web with a number of layers establish the number of separated Corresponds to the material pads. Such machines will often for fast paper production of moderate qualities.

It is a problem that such machines in which increasing variety of paper types, partly only can be underused because the only thing manufactured product does not find enough sales.

It is an object of the invention, the known To develop sheet formation system and a further use of a known multi-layer Open the headbox so that the Product range of the associated paper machine is expanded.  

This object is achieved by the features of claim 1 and use claim 2 .

Accordingly, the known sheet formation system becomes one Paper machine or board machine with at least a multi-layer headbox further developed that at least one seven-sided Layer of the headbox or headbox a connection to the white water cycle of Paper machine has so that this layer only with white water and / or water can be operated.

According to the further aspect of the invention, a N-layer headbox to create an (N-1) -layer Paper web used by at least a near-sieve layer with white water and / or water is operated.

In a fourdrinier paper machine, the Multi-layer headbox operated so that the Lower layer, which is directly connected to the first fourdrinier Comes into contact with white water and / or water is operated.

Another option can be a three or Multi-layer headbox that in conjunction with a gap former is operated in such a way that the two outer layers with white water and / or Water and the middle class respectively Middle layers are loaded with fabric suspension.

The use of the multilayer Headbox has the advantage that by  additional water supply in the sieve side Layer the actual sheet formation later starts. With a gap former, the outer White water or water layers of the formation-damaging effect of the forming roller be reduced and the consistency of entry into the Shaper to be moved to a cheaper area. This makes it possible to use paper machines that usually for fast production of Papers of moderate quality are also designed for the temporary production of high quality papers to use. This makes it possible to change the product range to round off this paper machine without costly conversions on a paper machine become necessary.

Further advantages of the invention are:

• - It is for a uniform impregnation of the Siebes worried, creating a more even Formation arises.
• - By embedding the suspension jet in White water becomes the direct contact of the Avoid suspension jet with the air, so that no boundary layer turbulence in the suspension arises. In addition, the turbulence of the Suspension beam through the mass of the Steamed white water, which in turn creates a better formation arises because there is no additional formation Increase in turbulence through mechanical Guide surfaces are available. A free jet, based on the suspension layer avoided because the suspension layer is always from is surrounded by a protective layer of water. On  this way can be supreme Machine speeds can be realized.
• - There is the possibility by concentration the white water with fillers from the outside into the Mix in filler suspension surface. This results in a better filler Z profile (Smiley profile = higher edge Concentration than inside the leaf). This Distribution is for example for SC papers from Advantage.
• - By concentrating the white water Fine substances are mixed into the suspension. This will result in better surface strengths (Pick resistance), bending stiffness and Shrink resistance in cardboard and Packaging paper achieved. Likewise, at Plybond multi-screening machines (cohesion several layers of paper made separately when merging) increased.

Further embodiments of the invention are in the Subclaims to claim 1 and in the following Figure descriptions shown.

It is understood that the above and features of the Invention not only in the specified Combination, but also in other combinations or can be used alone without the Leave the scope of the invention.

Further features and advantages of the invention result preferred from the following description  Embodiments with reference to the Drawing.

Fig. 1 inventive three-layer headbox.

Fig. 2 two-wire former with a three-layer and a single-layer headbox.

Fig. 3 two-wire former with a three-layer and a two-layer headbox.

Fig. 1 shows a sheet forming system of a three-layer headbox 10, the middle layer is fed with suspension 17.2, while the two outer layers are fed with the Siebwasserströmen 17.1 and 17.3. The stock suspension 17.2 , which is surrounded on the screen side by the white water streams 17.1 and 17.3 , is introduced from the headbox into the nip of the rollers 11 and 12 , where it is dewatered between the screens. The first drainage takes place through a suction segment 13 and the second drainage, on the opposite side, through a suction box 14 . Both the white water obtained by the suction segment 13 and the white water obtained by the suction box 14 are returned directly to the headbox. A white water circuit 16 is thus formed with respect to the upper sieve 19 and a white water circuit 15 is formed with respect to the lower sieve 18 . In both white water circuits 15 , 16 , the white water obtained in each case is fed back to the outer layer of the three-layer headbox. With this use of the three-layer headbox known per se, it is possible to produce high-quality paper for a short time in a paper machine, although the system itself is rather designed for particularly rapid mass production of paper of lower quality.

Fig. 2 shows a sheet forming system of a multi-ply paper with a single layer headbox 20.1 and a three-layer headbox 20.2. The single-layer headbox 20.1 passes its stock suspension 27.4 onto a lower screen 28 which is guided over a roller 21 . The stock suspension on the lower sieve 28 is dewatered by a dewatering unit 23.1 . A second sieve, the upper sieve 29 , is attached above the sieve 28 . A three-layer headbox places its stock suspension on the top wire 29 . According to the invention, this three-layer headbox is operated in such a way that the lower sieve-like layer is fed with white water or water 27.3 , while the two upper layers are loaded with material suspension of different consistency 27.1 , 27.2 . The fiber layer formed on the top wire 29 is deposited on the bottom wire 28 after the wire has been deflected via the roller 22.3 . The envisaged in the bottom wire 28 suction unit 23.2 supports the separation of the fiber layer from the top wire 29th

According to the invention, the suspension flow 27.1 facing away from the upper sieve 29 can also consist of white water which is exclusively enriched with very fine substances. This achieves a better connection of the two layers of paper that have formed on the top wire 29 and bottom wire 28 .

A further improvement of the sheet formation unit from FIG. 2 is shown in FIG. 3, in which the headbox 20.1 of the lower wire 28 is additionally designed as a two-layer headbox. In this headbox, the sieve-side layer is operated with white water 27.5 and the layer facing away from the sieve is fed with material suspension 27.4 . In such a configuration, the positive effect of the additional white water layer has been applied to both the lower and the upper layer of the resulting paper.

Reference list

10th

Three-layer headbox

11

roller

12th

roller

13

Suction segment

14

Suction box

15

White water cycle

16

White water cycle

17.1

,

17.3

White water flows

17.2

, Stock suspension flows

18th

Bottom sieve

19th

Top sieve

20.1

,

20.2

Headbox

21

roller

22.3

roller

23.1

Drainage unit

23.2

Suction unit

27.3

,

May 27

White water flows

27.1

,

27.2

,

April 27

Suspension flows

28

Bottom sieve

29

Top sieve

Claims (4)

1. Sheet formation systems of a paper or board machine with at least one multi-layer headbox, characterized in that at least one sieve-side layer of the headbox or headboxes has a connection to the white water circuit of the paper machine, so that this layer is operated exclusively with white water and / or water can. 2. Use an N-layer headbox for Production of an (N-1) -layered paper web, with at least one near-sieve layer White water and / or water is operated. 3. Use according to claim 2, characterized characterized in that in connection with a Sieve the bottom layer with white water and / or Water is operated. 4. Use according to claim 2, characterized characterized in that in connection with a Gap former with the two outer layers White water and / or water can be operated.