EP1081276A2 - Drying system - Google Patents

Abstract

The web drying station (10), in the prodn. and/or finishing of a paper or cardboard web (12), has an extended roller gap (S) to take the web (12) through it with at least one sieve (14,16) along the direction (L) of web travel. The roller gap (S) is formed between a flexible and continuous rotating belt (20) over a shoe (18) in a lower roller and an upper counter roller (22). The shoe (18) is divided into segments along the web line of travel, which are interconnected and subjected to separate forces at least partially. The shoe segments are at least partially linked together, and they are formed at least partially by zones of weakened material at the shoe (18), as cuts in succession along the line (L) of web travel on the side away from the press gap (S). The different temp. settings for the shoe segments give them an individual pressure profile in the press gap (S). The pressure in the gap (S) can be exerted by facing shoes (18), with at least one shoe (18) divided into segments. The surface of the continuous belt (20) and/or the counter surface (22) is structured and pref. grooved to equalize the pressure at the exit zone of the gap (S). The flexible continuous belt (20) is formed by the flexible mantle of a shoe roller (28), and the counter surface (22) is at a counter roller (30) with inner support and pref. a controlled bending roller (30). The continuous belt (20) over the shoe (18) is cooled, and the counter surface (22) is heated. A cooling medium (K) flows through the shoe (18) segments. The continuous belt (20) can be cooled externally and/or internally. The continuous belt (20) can also be cooled by a lubricant between it and the shoe (18). The sieves (14,16) are cooled before they enter the press gap (S), in the direction (L) of web travel. The continuous belt (20) over the shoe (18) can be heated, and the counter surface (22) cooled. The segmented shoe (18) is faced by a shoe without segments, which supports the counter surface (22). The two belts (20,22), forming the press surfaces, can each pass around floating deflection rollers and pref. bending compensation rollers, which also drive them. A separate and cooled steel belt (20') can be at the side of the shoe press roller.

Description

The invention relates to a drying device for a machine Production and / or treatment of a material web, in particular paper or cardboard web, in which the material web together with at least a sieve through a gap extended in the direction of web travel is guided between a rotating one supported on a shoe flexible endless belt and a counter surface is formed. It affects further a smoothing device specified in the preamble of claim 21 Art.

A drying device of the type mentioned at the outset is, for example known from DE 197 23 163 A1. It is also known to dry between two metal bands, one of which is heated and the other is chilled and between those starting from the heated Tape to the cooled tape, the paper web, a fine sieve and a coarse sieve are passed through. Arrangements are also known where the paper web and the screens are cooled or heated Cylinders are guided. A metal band is wrapped around the cylinder, that is heated with the cylinder cooled and with the cylinder heated is cooled. The paper web lies against the hot surface. Between the paper web and the cooled surface is at least again a sieve, usually a fine sieve lying against the paper web and a coarse sieve provided against the cooled surface is provided. With all of these arrangements, the pressure during the drying process by means of a pressurized gaseous or liquid cooling and / or Heating medium over an airtight surface such as in particular Metal tape on the sandwich formed between the two surfaces Transfer paper, fine sieve and coarse sieve (DE-A-26 57 041, Fig. 10; DE-A-32 03 571, Fig. 11; DE-A-35 32 853, Fig. 12).

The pressurized liquid now requires in terms of Seal and in view of unbalanced forces very complex constructions. A change in the applied structural pressure is only possible through several pressure chambers, which again the constructive Increase effort.

Facilities are also known in which the pressure during the Drying mechanically generated by one or more shoe presses will be pressed against a heated cylinder. So that the design effort required to generate the structural pressure can be reduced, and the pressure profile can be selected by choosing the shape of the Shoes are preselected within certain limits (EP-A-0 890 675, Fig. 13). However, if only one shoe is used, the length is the same from about 200 to 300 mm, which is very short. Become several shoes used, the paper between the individual shoes is used again and again relieved. No continuous process can be built up with that, because After each nip, the vapor pressure inside the paper must be at the outside pressure lowered to avoid destroying the paper.

In addition, solutions are known in which the structural pressure generated by several load rollers against a heated cylinder becomes. Here, too, there can be no continuous course of the structural pressure built up over a longer period of time (see e.g. US-A-5 787 603, Fig. 14).

The aim of the invention is to provide a drying device of the type mentioned Way of creating one during the drying process continuous course of the structural pressure in the web running direction over a significantly longer distance is possible. In addition, one should appropriate smoothing device can be created.

With regard to the drying device, this object is achieved according to the invention solved in that the shoe is segmented in the direction of web travel and that the interconnected shoe segments at least partially can be acted on separately.

Due to this training, a can during the drying process continuous course of the structural pressure in the machine direction generated over a significantly longer distance than, for example, 300 mm. It is possible, for example, to keep the profile of the pressing forces during monitor the operation of the pressure sensors and control them so that especially in the area of the exit from the pressure area the vapor pressure is small enough to destroy the paper due to it still in the paper to prevent contained expanding steam. You can do this, for example Appropriate force sensors can be provided in the shoe. Is the all-round flexible endless belt, for example through the flexible Roll jacket formed a shoe roller, so can corresponding Pressure sensors and force sensors, for example, in the rotating one Shoe roll or be provided in the counter roll to the shoe press roll.

The shoe is mechanically pressed against the counter surface to the Apply structural pressure to the material web. Over the whole the shoe segments across a jump-free occurs during operation preferably adjustable pressure profile. The load on the segments can for example at the connection points and / or in between hydraulic stamping.

In an expedient practical embodiment, the shoe segments at least partially articulated together. In this The segments can fall at the hinge points and / or in between be applied accordingly.

In a further expedient embodiment, the shoe segments are at least partially through areas of a respective material weakening of the shoe. So the shoe on its side facing away from the gap Advantageously, several consecutive in the web running direction Have incisions.

In a preferred practical embodiment of the invention Drying devices are subject to an appropriate application the shoe segments different pressure profiles in the gap adjustable.

The pressure in the gap can also be caused by two opposite one another Shoes are produced, at least one of the two shoes being segmented is.

It is also advantageous if the surface of the flexible endless belt and / or the counter surface to support pressure equalization in the area the gap outlet is structured accordingly, for example grooved, is.

In an expedient practical embodiment of the invention The drying device is the all-round flexible endless belt formed by the flexible roll shell of a shoe roll.

The counter surface can in particular by a counter roller, for example an internally supported roller, in particular a bending compensation roller, is formed his.

In certain cases, it is useful if this is carried over the shoe flexible endless belt cooled and the counter surface is heated. In this The segmented shoe can fall from a cooling medium, for example Cooling water, be flowed through. Alternatively or additionally, too the flexible endless belt supported on the shoe from the outside and / or from be chilled inside.

The flexible endless belt is advantageously at least partially on the inside by lubricating the area between the shoe and the endless belt serving lubricants, especially lubricating oil, cooled.

In certain cases it can also be useful if the sieve is in Web direction is cooled before the nip.

The flexible endless belt can be used to improve heat transfer in particular be formed by a steel band.

In a further expedient embodiment of the invention The drying device is the flexible one that runs over the shoe Endless belt heated and the counter surface cooled.

In an advantageous practical embodiment, both are flexible Endless belt as well as the counter surface each by a steel belt formed, the segmented shoe preferably a non-segmented Opposite shoe on which the steel band forming the counter surface is supported. The two steel strips are preferably each around two floating deflection rollers, preferably bending compensation rollers, guided and driven by this.

The smoothing device according to the invention is characterized in that the heated roller is a shoe roller, the flexible roller shell in the Gap area supported by a shoe segmented in the direction of web travel is, the interconnected shoe segments at least can be partially charged separately. Otherwise, this smoothing device have the same structure as the drying device.

Figur 1

eine schematische Darstellung eines segmentierten Schuhs einer Trocknungsvorrichtung,

Figur 2a, 2b

eine schematische Darstellung weiterer Ausführungsformen eines segmentierten Schuhs,

Figur 3

eine schematische Darstellung einer Trocknungsvorrichtung mit gekühlter Schuhwalze und beheizter Gegenwalze,

Figur 4

eine schematische Darstellung einer weiteren Ausführungsform einer Trocknungsvorrichtung mit beheizter Schuhwalze und gekühlter Gegenwalze und

Figur 5

eine schematische Darstellung einer weiteren Ausführungsform einer Trocknungsvorrichtung mit einem zwischen zwei Stahlbändern gebildeten Spalt.

The invention is explained below using exemplary embodiments with reference to the drawing; in this show:

Figure 1

1 shows a schematic representation of a segmented shoe of a drying device,

Figure 2a, 2b

1 shows a schematic representation of further embodiments of a segmented shoe,

Figure 3

1 shows a schematic representation of a drying device with a cooled shoe roller and a heated counter roller,

Figure 4

a schematic representation of a further embodiment of a drying device with heated shoe roll and cooled counter roll and

Figure 5

is a schematic representation of another embodiment of a drying device with a gap formed between two steel strips.

Figures 3 to 5 each show a purely schematic representation Drying device 10 of a machine for manufacturing and / or treatment a material web 12, which is in particular a Paper or cardboard web can act.

The material web 12 is together with one that touches the web 12 finely structured sieve 14 and a roughly structured sieve 16 an extended in the web running direction L gap S, which between a circumferential flexible endless belt supported on a shoe 18 20 and a counter surface 22 is formed.

The shoe 18 is segmented in the web running direction L, the individual Shoe segments 18 '(see also FIGS. 1 and 2) connected to one another and can be acted upon at least partially separately.

Figures 1 and 2 show two possible embodiments of the segmented Shoe 18.

As can be seen from FIG. 1, the shoe segments 18 ' be articulated together. The loading of the shoe segments 18 'can, for example, in the articulation points 24 and / or in between done with hydraulic stamps.

The shoe segments 18 'can also, for example, pass through areas of a respective weakening of material of the shoe 18 may be formed. So the Shoe 18 in the embodiments according to Figures 2a and 2b its side facing away from the gap S a plurality of successive ones in the web running direction L, incisions forming the respective material weakening 26 on. As can be seen from FIG. 2b, the incisions can be made 26, for example, in an area referring to a “normal profile” subsequent "relief" area may be provided.

The shoe 18 is thus mechanically opposed to a shoe press the counter surface 22 is pressed to apply the structural pressure to the material web 12 exercise. After the shoe 18 in connected segments 18 'is subdivided, results in the web running direction L over a relative a continuous course of structural pressure over a long distance. This continuous course can become clear, for example extend more than about 300 mm. The profile of the pressing forces can during operation is monitored by pressure sensors and controlled in such a way that especially in the exit from the pressure range the vapor pressure is small enough to destroy the paper due to it still in the paper to prevent contained expanding steam. You can Force sensors in the shoe 18 and / or pressure sensors and force sensors within the rotating flexible endless belt 20 or in the counter roll be arranged.

In the respective drying device 10 temperatures of for example about 100 to about 250 ° C and pressures up to about 60 bar and preferably prevail up to about 15 bar. The structural pressure can, as described below by way of example with reference to FIG. 5, also applied by two opposing shoes , at least one of which is segmented.

The pressure compensation when leaving the pressure area or gap S. can be formed by appropriately shaped or structured surfaces of the circumferential flexible endless belt 20 and / or the counter surface 22 be supported. For example, the surfaces in question can be grooved his.

To prevent delamination and to check the optimal Adjustment of the pressure profile of the shoe 18 can with the machine running suitable paper properties such as the modulus of elasticity and / or the thickness can be measured online. The modulus of elasticity can, for example be determined with a suitable ultrasound device. Shows there is an increase in the thickness or a decrease in the stiffness of the paper can reduce the pressure profile at the end of the shoe 18 for so long and / or modified until the desired optimum is reached. Automatic control algorithms can be defined. So can for example, based on the known and measured parameters and the pressure profile with a simulation of the drying process and determine the best possible change in the pressure profile. After that the pressure profile can be changed automatically.

The sieves 14, 16 and the material web can be made in a manner known per se 12 be flushed with steam D before entering gap S, thereby the extremely poorly heat-conducting air from the paper and the Seven is ousted. Heating is alternatively or additionally possible with other suitable means.

In the embodiments shown in Figures 3 and 4 one Drying device 10 is the rotating flexible endless belt 20 in each case through the flexible roll shell of a shoe roll 28 and the counter surface 22 formed by a counter roller 30. The in the direction of web travel L measured length of the gap S can for example be in a range from about 500 mm to about 1000 mm. The diameter of the rollers 28, 30, for example, in a range of approximately 1800 mm lie. The counter roller 30 can in particular be supported by an inside Roll, preferably a bending compensation roller, be formed (see. In particular Figure 3).

In the embodiment according to FIG. 3, the shoe roller 28 is cooled and the counter roll 30 is heated. The segmented shoe 18 of a cooling medium K, for example cooling water, flows through. The frictional heat between the loading elements 32 and the jacket of the Counter roll 30 can optionally be used to support the heating of the counter roll 30 can be used. Up to about 180 ° C all types of heating are inside and outside the roller, conceivable. That is, for heating the Counter roll 30 can, for example, steam, gas, a heat transfer medium, Heating oil, inductive heating and / or the like can be used. For higher temperatures, an additional steam must be added Heat generation can be selected.

The jacket of the shoe roller 28 can be a so-called Qualiflex jacket his. The shoe roller 28 is cooled in that the divided into segments Shoe 18 from the cooling medium K, e.g. Cooling water, flows through becomes. In addition, the jacket of this shoe roller 28 can be cooled from the outside his. Additionally or alternatively, the lubricating oil can be used for cooling can be used from the inside. To improve the heat transfer for cooling, is also a roller jacket made of a steel strip conceivable. In this case, the side seal must be different from that of the shoe presses common today are designed so that the coat only one undergoes flat deformation (e.g. through a rubber hose).

It is also possible to have a separate, cooled steel band 20 'over the flexible one Guide the plastic press jacket of the shoe press roll through the nip (see Figure 3).

Another cooling option is the sieves 14, 16 in front of the Cool gap S. The steam lock could then only be on the paper side be used. In the embodiment shown in Figure 4 the shoe roller 20 is heated and the counter roller 30 is cooled. The Heating thus takes place from the side of the shoe roller 28. Possibly. can the result of the friction of the jacket 20 on the shoe 18 Heat for heating the gap S can also be used.

In the latter case, however, the jacket and the lubricant would have to be removed one up to the temperature used, e.g. from about 140 ° C to about 180 ° C, resistant material. As already related to the embodiment according to FIG. 3 could also be mentioned, for example here the jacket 20 consist of steel and with a modified seal be provided on the edge. When using oil are currently Temperatures up to about 180 ° C, for example, are conceivable. To do this, however the oil is airtight, for example a nitrogen filling or the like can be provided within the shoe roller 28. Alternatively For example, sliding materials, e.g. Bearing metal with embedded Graphite.

Otherwise, this embodiment has at least in accordance with FIG essentially the same structure as that of Figure 3. Moreover, this can In principle, the embodiment shown in FIG. 4 also for smoothing be used. In this case, the sieves and the steam lock fall away, and only the paper is fed through the heated nip. Corresponding the counter roller 30 can be cooled to the respective requirements, be uncooled or heated. Likewise, by the amount of the introduced Heat at the same time as smoothing also increased the dry content become.

As can be seen in particular from FIG. 5, the pressure in the Gap S also through two opposing shoes 18 and 34 be generated, only shoe 18 being segmented in the present case.

In the embodiment according to FIG. 5, this is both about the segmented Shoe 18 guided flexible endless belt 20 as well as the counter surface 22 each formed by a steel band. The segmented shoe 18 lies the non-segmented, firm shoe 34, on which the Counter surface 22 forming steel strip is supported.

The two steel strips 20, 22 are each around two floating deflecting rollers 36, 38, preferably bending compensation rollers, guided and driven by this.

The friction between the steel belts 20, 22 and the deflection rollers 36, 38 can be improved by suitable surfaces of the rollers. For example, grooved and / or coated with hard metal Roll surfaces can be provided.

Between the two respective deflection rollers 36, 38 is the one with structural pressure acted upon, formed by the gap S through the formed two opposing pressure shoes 18, 34. The Shoe 18 again consists of segments 18 'which can be acted upon separately. (see also Figures 1 and 2). The opposite shoe 34 is stationary, taking measures to compensate for the deflections may or may not be.

In the present case, the segmented shoe 18 is cooled and not segmented fixed shoe 34 heated. The heating can for example again similar to the embodiment shown in Figure 2, wherein here too the frictional heat can be used. In terms of the sliding process of the band on the shoe must be taken into account, that heat-resistant material is used.

The cooling can be done by cooling channels in the respective shoe 18 and / or through which, for example, lubricant consisting of oil or water takes place, which is applied to the band 20 in front of the shoe 18. The steel strips 20, 22 are made wider than the sieves 14, 18. Das zur Lubrication between bands 20, 22 and shoes 18 and 34, respectively medium used can easily by on the driver's side and the On the drive side next to the shoes on the belt sliding seals are collected and after the shoes by a wedge-shaped scraper, for example 40 can be collected again.

In FIG. 5, the heating device assigned to the heated fixed shoe 34 is designated by H. Cooling coils for the cooling medium assigned to the segmented shoe 18 are denoted by K ₁ . A box 42 is assigned to the non-segmented, solid shoe 34.

Which are derived from the preceding description and the individual figures resulting features can also be provided individually or in any Wise combined with each other.

Reference list

10th

Drying device

12th

Material web

14

finely structured sieve

16

roughly structured sieve

18th

segmented shoe

18 '

Shoe segments

20th

all-round flexible endless belt

20 '

chilled continuous flexible endless belt

22

Counter surface

24th

Hinge points

26

Material weakening, cuts

28

Shoe roller

30th

Counter roll

32

Load element

34

non segmented shoe

36

Deflection roller

38

Deflection roller

40

Wipers

42

box

D

steam

H

Heating device

K

Cooling medium

L

Web direction

S

gap

Claims (21)

Drying device (10) of a machine for producing and / or treating a material web (12), in particular paper or cardboard web, in which the material web (12) together with at least one sieve (14, 16) through a gap extended in the web running direction (L) (S), which is formed between a circumferential flexible endless belt (20) supported on a shoe (18) and a counter surface (22),
characterized by
that the shoe (18) is segmented in the web running direction (L) and that the interconnected shoe segments (18 ') can be acted upon at least partially separately. Drying device according to claim 1,
characterized by
that the shoe segments (18 ') are at least partially articulated together. Drying device according to claim 1 or 2,
characterized by
that the shoe segments (18 ') are at least partially formed by areas of a respective material weakening (26) of the shoe (18). Drying device according to claim 3,
characterized by
that the shoe (18) on its side facing away from the gap (S) has a plurality of incisions (26) which follow one another in the web running direction (L). Drying device according to one of the preceding claims,
characterized by
that different pressure profiles in the gap (S) can be set by appropriately loading the shoe segments (18 '). Drying device according to one of the preceding claims,
characterized by
that the pressure in the gap is generated by two opposing shoes (18, 34), at least one (18) of the two shoes being segmented. Drying device according to one of the preceding claims,
characterized by
that the surface of the flexible endless belt (20) and / or the counter surface (22) is structured, preferably grooved, to support the pressure compensation in the area of the gap outlet. Drying device according to one of the preceding claims,
characterized by
that the rotating flexible endless belt (20) is formed by the flexible roll shell of a shoe roll (28). Drying device according to one of the preceding claims,
characterized by
that the counter surface (22) is formed by a counter roller (30). Drying device according to claim 9,
characterized by
that the counter roller (30) is formed by an internally supported roller, preferably a bending compensation roller. Drying device according to one of the preceding claims,
characterized by
that the flexible endless belt (20) guided over the shoe (18) is cooled and the counter surface (22) is heated. Drying device according to claim 11,
characterized by
that the segmented shoe (18) is flowed through by a cooling medium (K). Drying device according to claim 11 or 12,
characterized by
that the flexible endless belt (20) is cooled from the outside and / or from the inside. Drying device according to one of the preceding claims,
characterized by
that the flexible endless belt (20) is at least partially cooled on the inside by the lubricant serving to lubricate the area between the shoe (18) and the endless belt (20). Drying device according to one of the preceding claims,
characterized by
that the screen (14, 16) is cooled in the web running direction (L) before the gap (S). Drying device according to one of the preceding claims,
characterized by
that the flexible endless belt (20) is formed by a steel belt. Drying device according to one of the preceding claims,
characterized by
that the flexible endless belt (20) guided over the shoe (18) is heated and the counter surface (22) is cooled. Drying device according to one of the preceding claims,
characterized by
that both the flexible endless belt (20) and the counter surface (22) are each formed by a steel belt and the segmented shoe (18) is opposite a non-segmented shoe (34) on which the steel belt forming the counter surface (22) is supported . Drying device according to claim 18,
characterized by
that the two steel strips (20, 22) are each guided and driven by two floating deflecting rollers (36, 38), preferably bending compensation rollers. Drying device according to one of the preceding claims,
characterized by
that a separate cooled steel band (20 ') is provided on the shoe press roll side. Smoothing device (10) of a machine for producing and / or treating a material web (12), in particular paper or cardboard web, in which the material web (12) is guided through a gap (S) which is between a heated roller (28) and a Counter roll (30) is formed,
characterized by
that the heated roller (28) is a shoe roller, the flexible roller shell (20) of which is supported in the gap area by a shoe (18) segmented in the web running direction (L), the shoe segments (18 ') which are connected to one another can be acted upon at least partially separately.

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