EP1770205A2 - Belt for transferring a fibrous web during manufacture thereof - Google Patents

Abstract

The belt (1) which comprises at least a textile carrier material and a coating applied thereto to contact the fibre web such as paper or cardboard web being produced has over its entire width at least one characteristic feature ( C) which is permanently different in at least one area. The characteristic can be a direct product parameter of the belt such as material used, thickness of the carrier material, penetration of the coatings, structural design of the belt; or an indirect product parameter such as roughness, bending strength, pore size. Independent claim describes machine such as paper or cardboard machine producing paper webs wherein at least one machine area has a belt as above for transferring the fibre web. Independent claim describes use of belt for transferring paper web in machine area or between two machine areas of a fibre web manufacturing machine.

Description

The invention relates to a belt for transferring a fibrous web to be produced, in particular paper or board web, in a machine area of a machine producing the fibrous web, in particular paper or board machine, consisting of at least one textile carrier material and a coating attached to the carrier material and the fibrous web to be produced to achieve a partial or complete impermeability of the tape.

Furthermore, the invention relates to both a machine, in particular paper or board machine, for producing a fibrous web, in particular paper or board web, as well as a use of a belt for transferring a fibrous web to be produced, in particular paper or board web, in a machine area or between two machine areas a machine producing the fibrous web, in particular a paper or board machine.

Such a belt for transferring a fibrous web to be produced in a machine area of a machine producing the fibrous web is already known from a large number of publications. Purely by way of example, the two documents EP 0 576 115 B1 ( DE 693 02 136 T2 ) and US Pat. No. 6,605,188 B2 be cited.

The band should generally ensure stable running of the fibrous web to be produced by the machine. This is especially true in the Machine areas of importance in the machine in which the fibrous web to be produced is not guided by a roller or a belt, such as a screen belt, a press felt or a drying wire.

The known tapes all have different properties, in particular in the area of their surfaces facing the fibrous web to be produced. Thus is from the cited document EP 0 576 115 B1 a web contacting surface having a pressure responsive, recovering degree of roughness. The further mentioned document US Pat. No. 6,605,188 B2 On the other hand, a tape is disclosed which consists of a base structure and a cover layer contacting the fibrous web to be produced. The cover layer comprises at least two fiber types with different properties, such as hydrophilic versus hydrophobic. Further different properties may also be the polarities, the hydrophilic properties, the electrical charges, the surface tensions, the coefficients of friction, the finenesses or the porosities.

The different properties of the bands disclosed in the cited references always relate to their total areas, that is also over the total widths of the respective bands. As a result, different transverse profiles of the respective fibrous web during manufacture can not be sufficiently taken into account, so that ultimately always a compromise in terms of quality loss and rejection must be addressed.

Furthermore, the document discloses US 6,770,172 B2 an endless, consisting of a base fabric and at least one nonwoven layer press felt having in its two edge regions each have a different structure than in the central region. However, in the various areas, the corresponding structure is the same in area area. In other words, that means that the respective area area has a non-differentiating characteristic. Overall, this embodiment achieves, inter alia, improved guiding of the material web through the press nip.

The invention is therefore the object of developing a band of the type mentioned so that different cross sections of the fibrous web can be better compensated during their production. Furthermore, a corresponding machine and a corresponding use to be specified.

This object is achieved in a band of the type mentioned according to the invention in that it has over its entire width at least one in at least one area, preferably continuously differing characteristic.

The object of the invention is completely solved in this way.

Due to the fact that the band over its entire width has at least one in at least one area preferably continuously differing characteristic, the possibility is created, different, possibly machine-specific cross-profiles, such as the moisture profile, the fibrous web during their production better considered, ie to be able to compensate for other things. This possibility creates improved conditions for the production of a higher quality fibrous web at a significantly better manufacturing and quality rate.

Furthermore, the essential task of the band to guide the fibrous web to be produced by at least one press nip and subsequent open draws, noticeably better fulfilled.

But other tasks of the band, such as the equalization of water and / or air flow, at least during the leadership of the fibrous web to be produced by the press nip, are better met.

Thus, for example, owing to a varying roughness (characteristic) over the entire width, the distribution of the water present in the fibrous web to be produced can be optimized, at least in the press nip. This should have the purpose that the dewatering is evened out towards the press felt and thus the dry content of the fibrous web to be produced over the entire width of the machine is significantly improved. At the same time, it can also be deduced that the two-sidedness of the fibrous web to be produced is improved, since the potential leaching of fillers can be controlled by equalizing the water flow.

Moreover, due to a varying roughness (characteristic) over the entire width, for example, the distribution of the air in the so-called filter cake can be controlled at least in the press nip. Due to the rough surface of the press felt, the air can escape in a controlled manner through the fine grooves which have formed during the grinding process and thus contribute to a more homogeneous structure of the fibrous web to be produced, for example with respect to bulk and porosity.

For the spatial definition of the characteristic, several preferred options are advantageous according to the invention: the characteristic differs symmetrically in at least two regions or asymmetrically in at least one region, in particular randomly distributed to the band center of the band; the characteristic differs only in the two edge regions or in the middle region of the band Bands and / or the characteristic differs in several areas periodically and / or in several areas across the entire width of the band. The respective differentiation of the characteristic takes place here moreover, preferably continuous. All these advantageous possibilities of differentiation open up a wide range of applications of the belt according to the invention for fibrous webs with different, possibly machine-specific transverse profiles.

The characteristic preferably comprises at least one direct product parameter of the band, such as material used, thickness of the carrier material, depth of penetration of coatings, structural design of the band or the like, and / or at least one indirect product parameter of the band, such as roughness, bending stiffness, Compressibility, permeability, permeability, recovery, pore distribution, pore size, pore size distribution or the like.

Furthermore, the differing characteristic preferably results from adding and / or removing material components or material components and / or from a change in the production process over the entire width of the band. These two ways of producing the characteristic of the tape are characterized among others by a simplicity, a speed and a cost advantage.

The machine according to the invention, in particular a paper or board machine, for producing a fibrous web, in particular a paper or board web, is characterized in that at least one machine area has a web for transferring the fibrous web to be produced according to one of the preceding claims. This machine area is preferably the press section for dewatering and / or the dryer section for drying the fibrous web to be produced.

The inventive use of a belt for transferring a fibrous web to be produced, in particular paper or board web, is preferably in a machine area or between two machine areas of a fibrous web producing machine, in particular paper or board machine provided. The machine area may be the press section for dewatering and / or the dryer section for drying the fibrous web to be produced.

Further features and advantages of the invention will become apparent from the dependent claims and the following description of preferred embodiments with reference to the drawing.

Figuren 1 und 2

zwei beispielhafte Profile für jeweils ein über die Breite hinweg vorzugsweise stetig differierendes Charakteristikum eines erfindungsgemäßen Bands;

Figur 3

eine Draufsicht auf ein erfindungsgemäßes Band mit einem über die Gesamtbreite hinweg vorzugsweise stetig differierenden Charakteristikum;

Figur 4

eine schematische Darstellung der Wirkung des vorzugsweise stetig differierenden Charakteristikums des erfindungsgemäßen Bands der Figur 3; und

Figuren 5 bis 8

mehrere Schnittdarstellungen möglicher Ausführungsformen des erfindungsgemäßen Bands.

Show it

Figures 1 and 2

two exemplary profiles for each one over the width of preferably continuously differing characteristic of a band according to the invention;

FIG. 3

a plan view of a band according to the invention with over the entire width, preferably continuously differing characteristic;

FIG. 4

a schematic representation of the effect of the preferably continuously differing characteristic of the band according to the invention of Figure 3; and

FIGS. 5 to 8

several sectional views of possible embodiments of the tape according to the invention.

FIGS. 1 and 2 show two exemplary profiles P for a characteristic C of a band 1 which preferably differs over the entire width B, which is generally used for transferring a fibrous web to be produced, in particular a paper or board web, in a machine region of a machine producing the fibrous web. In particular paper or board machine, is used and made of at least one textile substrate and a mounted on the substrate material and the produced fibrous web contacting coating to achieve a partial or complete impermeability of the tape 1 exists (see Figures 5 to 8).

The respective band 1 has over its entire width B across preferably continuously differing characteristic C on.

According to the embodiment of FIG. 1, the characteristic C in three regions B1, B2 and B3 differs symmetrically to the midband M, whereas according to the embodiment of FIG. 2 the characteristic C in the four regions B4, B5, B6 and B7 is asymmetrical, in particular randomly distributed to the midband M differs. Moreover, the respective differentiation of the characteristic C preferably takes place continuously.

In further embodiments, which are not explicitly illustrated, the characteristic C may also be present only in the two edge regions of the band 1, only in the middle region of the band 1, in several regions periodically over the entire width B of the band 1 and / or in several regions Preferably, the total width B of the band 1 will differ consistently.

Furthermore, the characteristic C comprises at least one direct product parameter of the band 1, such as material used, thickness of the carrier material, depth of penetration of coatings, structural design of the band or the like, and / or at least one indirect product parameter of the band 1, such as roughness, flexural rigidity, Compressibility, permeability, permeability, recovery, pore distribution, pore size, pore size distribution or the like.

The differing characteristic C results from adding and / or decreasing material components or material fractions and / or from a change in the manufacturing process over the overall width B of the band 1.

The respective band 1 is also outstandingly suitable for use in a machine area of a machine producing the fibrous web, in particular a paper or board machine, wherein the machine area may be the press section for dewatering or the dryer section for drying the fibrous web.

FIG. 3 shows a plan view of a band 1 with a characteristic C. differing over the overall width B.

The selected characteristic C is, for example, the transmittance D, which differs symmetrically from the mid-band M. The differing transmittance D can be achieved, for example, by a different needling intensity over the total width B of the band 1. In the two edge regions of the band 1, the needle-punching intensity is the highest, whereas it is the lowest in the region of the center of the web M. In between, areas with average needle punching intensity are arranged. The areas are indicated by different hatch intensities. It is also obvious that the characteristic C of two adjacent areas of the tape may overlap, so no sharp separation contour between the two adjacent areas of the tape must be present.

FIG. 4 shows a schematic representation of the effect of the differing characteristic C of the band 1 of FIG. 3.

The effect achieved in the form of the permeability D, in particular in the form of the air permeability L, varies symmetrically with respect to the center of the strip M and can vary, for example, in a range of> 0 to 10 cfm.

Each of FIGS. 5 to 8 in each case shows a sectional view of a possible embodiment of the band 1 according to the invention, which in principle comprises at least one textile substrate 2 and a mounted on the substrate 2 and the non-illustrated fibrous web contacting coating 3 to achieve a partial or complete impermeability of the tape 1 consists. The carrier material 2 preferably has a load-absorbing structure.

Moreover, the respective band 1 shown in FIGS. 5 to 8 has a characteristic that differs over its entire width, preferably continuously differing, as shown, for example, in FIGS. 1 and 2.

In the embodiment of FIG. 5, the band 1 is formed from two separate layers, from a carrier layer 4 formed by a textile carrier material 2 and from a cover layer 5 formed by a coating 3.

On the other hand, in the embodiment of FIG. 6, a coating 3 is completely or partially penetrated into a textile carrier material 2. Thus, the band 1 comprises a pure cover layer 5, which is formed solely from the coating 3, and a mixed layer 6, which is formed from the textile substrate 2 and the coating 3.

Furthermore, the band 1 in the embodiment of FIG. 7 again consists of a mixed layer 7, which is again formed from a textile carrier material 2 and a coating 3 in a mutual combination. The coating 3 is again part of a cover layer 5.

Finally, in the embodiment of FIG. 8, the band 1 has a layered structure with multiple layers. A coating 3 forms a non-illustrated fibrous web contacting cover layer 5 and a lower side adjacent support layer 4 is formed by a textile support material 2.

Furthermore, on the underside of the carrier layer 4 three further layers 8, 9 and 10 are mounted, which in turn preferably have load-absorbing structures and properties.

In summary, it should be noted that a band of the type mentioned above is developed by the invention so that different cross-sections of the fibrous web can be better compensated during their production. In addition, it can also result in effects that can be seen both in a quality improvement, that is, more homogeneous values, for example, for gloss, volume and the like over the entire width, as well as in an increase in production capacity of the machine, that is, less breaks / breaks of the web ,

LIST OF REFERENCE NUMBERS

1

Band (transfer band)

2

support material

3

coating

4

backing

5

topcoat

6

mixed layer

7

mixed layer

8th

layer

9

layer

10

layer

B

overall width

B1 to B7

Area

C

feature

D

permeability

L

Air permeability

M

mb

P

profile

Claims (15)

Band (1) for transferring a fibrous web to be produced, in particular paper or board web, in a machine area of a fibrous web producing machine, in particular paper or board machine consisting of at least one textile substrate (2) and one on the substrate (2) and the fibrous web contacting coating (3) to achieve a partial or complete impermeability of the tape (1),
characterized,
that it has over its entire width (G) at least one in at least one area (B1, B2, B3, B4, B5, B6, B7) preferably continuously differing characteristic (C). Belt (1) according to claim 1,
characterized,
that the characteristic (C) in at least two regions (B1, B2, B3) symmetrically different from the band center (M) of the band (1) preferably continuously. Belt (1) according to claim 1,
characterized,
in that the characteristic (C) in at least one region (B4, B5, B6, B7) preferably differs continuously asymmetrically, in particular randomly distributed relative to the band center (M) of the band (1). Band (1) according to claim 1, 2 or 3,
characterized,
that the characteristic (C) only in the two edge regions of the belt (1) preferably constantly differs. Band (1) according to claim 1, 2 or 3,
characterized,
that the characteristic (C) only in the central region of the belt (1) preferably constantly differs. Band (1) according to one of the preceding claims,
characterized,
that the characteristic (C) in several areas (B1, B2, B3) preferably differs continuously over the total width (G) of the band (1), preferably continuously. Band (1) according to one of the preceding claims,
characterized,
in that the characteristic (C) in several areas (B1, B2, B3, B4, B5, B6, B7) preferably differs continuously over the total width (G) of the band (1). Band (1) according to one of the preceding claims,
characterized,
that the characteristic (C) at least one direct product parameter of the tape (1), such as material used (2, 3), thickness of the carrier material (2), depth of penetration of coatings (3), structural design of the belt (1) or the like, includes. Band (1) according to one of the preceding claims,
characterized,
in that the characteristic (C) comprises at least one indirect product parameter of the tape (1), such as roughness, flexural rigidity, compressibility, permeability, permeability, recovery, pore distribution, pore size, pore size distribution or the like. Band (1) according to one of the preceding claims,
characterized,
that the differing characteristic (C) results from adding and / or removing material components (2, 3) or material components (2, 3). Band (1) according to one of the preceding claims,
characterized,
that the differing characteristic (C) results from a change in the manufacturing process over the total width (G) of the tape (1). Machine, in particular paper or board machine, for producing a fibrous web, in particular paper or board web,
characterized,
in that at least one machine region has a band (1) for transferring the fibrous web to be produced according to one of the preceding claims. Machine according to claim 12,
characterized,
that the machine area is the press section for dewatering and / or the drying section for drying the fibrous web. Use of a belt (1) for transferring a fibrous web to be produced, in particular a paper or board web, in a machine area or between two machine areas of a machine producing the fibrous web, in particular a paper or board machine, according to one of the preceding claims. Use of a belt (1) for transferring a fibrous web to be produced, in particular a paper or board web, in a press section, between a press section and a dryer section or in a dryer section of a machine producing the fibrous web, in particular a paper or board machine, according to one of the preceding claims.

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