JPH11200297A - Coating apparatus for wetting zone of machine for producing material web comprising especially paper or carton and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a coating apparatus which is improved so as to maintain a coating medium applied to a material web in the vicinity of the surface of the material web and so as to avoid the defect of the peeling off of the coating medium in coating, consequently is capable of being simplified in the structure and a method for coating corresponding to the apparatus. SOLUTION: In this coating apparatus, the apparatus has a roller 18 for guiding a material web 12 along a part in the peripheral direction in a winding and hanging zone, a coating mechanism 20 for coating the surface of the material web 12 or the surface of the roller 18 with a liquid or pasty medium and at least one straining belt 14 for supporting the material web 12 arranged between the coating mechanism 20 and the material web. A coating medium 24 is brought into contact with the material web 12 in the winding and hanging zone U of the roller 18. In this method for coating, the coating medium 24 is delivered from a moving endless air-permeable transporting belt to the material web 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus and a method for applying a liquid or pasty medium, directly or indirectly, to a finished web of wet material, especially paper or carton, which has been manufactured.

[0002]

2. Description of the Related Art German Patent Application Publication No. 1942348.
From the specification, for example, a coating device for applying a coating medium to a web of material received between two fourdrinces is known. Furthermore, suction devices are known for sucking out moisture from a still wet material web. Due to the relatively loose guidance inherent in the fourdrinier in the direction perpendicular to the plane of the material web, the material web has a relatively loose texture in the area of the coating device. Thus, the coating medium applied to the material web penetrates into the volume or interior of the material web and is not maintained in the surface area of the material web as originally desired. The coating apparatus known from DE-A 1 942 348 cannot therefore provide the coating properties required in modern machines for producing paper or cartons.

[0003] Further, US Pat.
The prior art disclosed in US Pat. No. 5,077,098 describes a coating apparatus for wet material webs. In this case, the web of fiber material is placed on the screen. On the side of the web of fibrous material which does not contact the screen, in the area of winding of the support rollers, another rotating roller delivers the coating medium to the surface of the web of fibrous material. The roller pair contacts the bus of the coating roller. The coating medium is metered in the wedge space above the roller pair. The rolling of the three rollers collectively distributes the coating medium to the surface of the coating roller.

[0004] A disadvantage of this arrangement is the rapidly opened gap between the support roller area and the coating roller area where the screen and the web of fiber material are wound after coating. This is caused by the relatively small radius of curvature of the coating roller. Adhesion of the coating medium to the fibrous material web surface as well as to the coating roller surface causes flaking on the surface.

[0005] Another disadvantage of this arrangement is the three-roller construction, which makes the construction expensive. Further, considerable space is required by the arrangement of the three rollers. This is because the coating device must be arranged directly along the web course.

In the prior art disclosed in US Pat. No. 4,793,899, application of the media takes place in the press section of a paper machine. In this case, the web of fiber material is likewise placed on a conveyor belt, in which case a press felt is used. Coating equipment (in this case “short-dwell
A coater ", described as a short dewel coater, applies the coating media to the surface of a non-felt coated press roller that forms a press nip with another press roller.

When the surface of the press roller rolls along the web of fiber material, the coating medium is delivered to the web of fiber material and pressed into the fiber strip. If the web of fibrous material leaves the press nip, this arrangement also suffers from the aforementioned disadvantages of spalling. The surface of the fibrous web with the coating medium in the manner described above has a rough surface. This causes problems during printing.
The primary cause of spallation is the coating nip, which opens very quickly. This opening speed creates a problem which increases gradually as the paper machine rotates faster.

[0008] In addition, US Patent No. 479389.
In the case of the coating apparatus known from DE-A 9 9, the problems caused by the loose structure of the material web are not noticeable and do not significantly affect the coating properties,
The coating medium is concentrated in the coating gap formed by the rollers so that the goal specified in this known specification of keeping the coating medium as close as possible to the surface of the material web is not achieved. You will be pushed inside.

[0009] In addition, US Patent No. 479389.
The coating apparatus known from US Pat. No. 6,077,028 has a large number of guides and press rollers for the material web and a screen for guiding the material web and thus requires a large amount of construction.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to improve a coating device for a dampening area of a machine, in particular for producing a material web of paper or carton, so that a coating medium applied to the material web is improved. Is maintained close to the surface of the material web and the disadvantages of spalling when applying the coating medium are avoided, these are made possible with a simple structure of the coating device and, furthermore, the corresponding coating method Is to be provided.

[0011]

According to the present invention, there is provided a coating apparatus comprising: a roller for guiding a material web in a wrapping region over a part of a circumferential direction; and a surface of the material web or a surface of the roller. A coating mechanism for applying a liquid or paste-like medium is provided, and at least one mesh belt for supporting the material web is disposed between the coating mechanism and the material web. The problem is solved by contacting the material web in the hanging area.

In addition, the object is to provide a paper machine according to the invention in which a liquid or paste-like coating medium is applied to a moving web of paper or carton having a dampening zone, a pressing zone and a drying zone. Papermaking machine comprising at least one conveyor for the material web to be produced, as a moving endless breathable belt, in the dampening zone, opposite the conveyor. In the type in which at least one coating mechanism for applying the coating medium to the material web side is arranged, the coating mechanism has a moving endless breathable transport belt for applying the coating medium to the material web. It was solved by doing.

[0013] A further object of the present invention is to provide a method for coating a material web consisting of paper or carton with a liquid or pasty coating medium, according to the coating method according to the invention. Forming a web of material with the material, guiding the web of material through an endless and preferably breathable belt during coating, and material that is still wet from the surface moving the coating media in the direction of web travel. The step of delivering to the web is accomplished by delivering the coating medium to the material web from a moving, endless, breathable conveyor belt.

[0014]

According to the present invention, there is provided an apparatus for directly or indirectly applying a liquid or pasty medium to a finished web of material, particularly paper or carton, which has been completed, wherein the apparatus comprises a roller. In this case, the roller guides the material web in a winding area over a part of the circumferential direction thereof, and the device further comprises a liquid or paste-like material on the surface of the material web or the roller. A coating mechanism for applying the media, and at least one mesh belt for supporting the web of material, wherein the mesh belt is disposed between the coating mechanism and the web of material and the coating medium is The material web contacts the roller winding area.

The mode of operation of the coating apparatus according to the invention is based, inter alia, on a combination of two features: on the one hand the coating medium contacts the material web in the area of the roller winding and on the other hand the coating medium is constantly filtered. It is based on being applied to the material web via a mesh, which is independent of whether the coating medium is applied to the material web from inside or outside the material web. In this case, the concepts “inside” and “outside” relate to the course of curvature of the material web in the winding area,
That is, "inside" means the side of the material web facing the roller, while "outside" means the side of the material web opposite the roller.

When the coating mechanism is located outside the material web, a mesh belt disposed between the coating mechanism and the material web compresses the fiber structure of the material web. Thus, the applied coating medium does not penetrate into the volume of the material web and is left in the region of the outer surface of the material web. If, on the other hand, the coating mechanism and thus the mesh belt are arranged inside the material web, the material web is compressed in the wrapping area on the basis of the existing connection of the fibrous structure, and thereby into the volume of the material web. Of the coating medium is prevented.

At the same time, the mesh belt acts as a pressure cushion for the hydrodynamic pressure formed at the entrance of the winding area. The pressure therefore does not take on such a value that the coating medium can penetrate through the compression zone into the volume of the material web. For this reason, no opposing roller is provided outside the material web. Thus, the material web diverts pressure peaks of the applied coating medium and thus prevents penetration of the coating medium into the volume of the material web. Furthermore, the coating device according to the invention has a simple structure. This is because the coating device only requires a winding roller, a mesh belt and a coating mechanism in terms of basic equipment.

When the coating mechanism is arranged outside the material web and when the coating mechanism is arranged inside the material web, it is advantageous if the material web is received between two mesh belts. In the former case, a second mesh belt provided inside the material web prevents direct contact between the roller surface and the material web. This in particular prevents damage to the material web due to inadvertent adhesion to the roller surface at the end of the winding area. In the latter case,
A second mesh belt provided outside the material web contributes to the compression of the material web.

When the material is applied from outside the web, according to a first variant, the coating mechanism makes sliding contact with the mesh belt. This arrangement ensures, in a simple manner, that the coating medium contacts the material web via the mesh belt. In this case, the coating arrangement has a coating chamber from which the coating medium flows under pressure and comes into contact with the material web via a mesh belt. By appropriate selection of the pressure values to be controlled in the coating chamber, the coating medium is pressed into the material web at the desired depth.

However, according to an optional second variant, the coating mechanism is spaced from the mesh belt and can be configured, for example, as a free jet nozzle mechanism. In this case, the coating medium gradually flows through the mesh belt and comes into contact with the material web.

In both variants, a removal device can be arranged downstream of the coating mechanism for removing excess coating medium from the material web. In particular in connection with the first variant described above, the removal device can be arranged immediately downstream of the coating mechanism. Equalization to additionally or selectively equalize the coating medium downstream of the coating mechanism, and to remove excess coating medium from the material web if desired, to ensure as uniform a coating as possible Equipment can be arranged. This equalizer has, for example, a scraper device or another known doctor unit.

In the case of application from the inside of the material web, that is to say via the roller surface, according to another variant, the coating mechanism is in sliding contact with the roller surface or according to another variant. It is arranged at a distance from the roller surface.

In each of the above cases, the roller advantageously has a negative pressure zone extending over at least a part of the winding area. When applied from the outer surface of the material web, the moisture present in the still wet material web is drawn off towards the rollers, which facilitates the fixing of the coating medium in the outer surface area of the material web. When applying from the inside of the material web, the arrowhead negative pressure zone removes excess coating media from the surface of the material web.

As already described in the context of one use case, the coating arrangement has a coating chamber through which the coating medium flows under pressure. For example, 300Pa to 10kP in the coating chamber
a, a pressure of 500 Pa to 5 kPa can be advantageously controlled. The working time is between 1 ms and 10 ms. In order to save as much of the coating medium as possible, the coating mechanism is adapted to meter and supply the coating medium.

The radius of the roller is from 200 mm to 1200
mm. Further, the solids content of the paper web is 5 to 50 percent, preferably 8 to 17 percent, and the solids content of the coating medium is 5 to 50 percent,
Advantageously it is between 10 and 30 percent. In this case, the coating medium is, for example, water, a mineral filler,
For example, kaolin, CaCO ₃ , TiO _2, etc., a bonding material such as starch, latex, etc., a holding agent and an optical brightener.

Thus, the invention does not propose to use a roller as a coating element, but rather to provide a coating gap which is slowly opened in another form, in which case the material web is The transfer of the coating medium takes place by means of a conveyor belt which approaches the material web at a low speed and also leaves the material web at a low speed after the coating.

This has a number of advantages. That is, in one aspect, the coating medium is already in contact with the material web short of the press gap, thereby extending the working time of the coating medium on the material web. On the other hand, the peeling speed of the transfer belt from the material web behind the press gap is significantly reduced compared to roller coating. In order to ensure that the entrained air boundary layer on the felt and web in this elongated coating wedge does not form an undesirable barrier between the coating medium and the material web, the transport belt must be breathable. Breathability is also required when the transfer nip is opened so that the material web can be detached from the conveyor belt again.

The coating medium is applied to the conveyor belt by a coating roller. An arrowhead coating medium is applied to the peripheral surface of the coating roller by a doctor device. The coating apparatus according to the present invention includes a transport belt and a coating mechanism. The coating mechanism is realized by a coating roller. However, it is also possible to use a coating mechanism (three-roller mechanism) with an attached pair of rollers to wet the transport belt.

Another advantage of the described coating apparatus is that part of the coating apparatus (transport belt) is often existing and thus does not require additional space requirements. The other part of the coating apparatus (coating mechanism) can be placed away from the web where there is sufficient space.

The coating apparatus according to the invention can be used at various points in the damping zone and / or the press zone area of the paper machine.

An advantageous point of use is at the beginning of the press section. The web of fibrous material is pre-dewatered by the screen section and the first web of the press section from the screen section using felt.
Reaches the press gap. The second felt, to which the coating medium is applied by the coating mechanism, enters the first press gap in a wedge-like manner in cooperation with the first felt. Due to the still very high water content of the fibrous material web, a penetration of the coating medium into the fibrous material web occurs, which is characteristic for this point of use.

It is furthermore advantageous if another dewatering of the fibrous material web takes place in the first press gap in the press section first. Based on the changed properties of the web of fibrous material after the first pressing, further web properties of fibrous material are obtained in this region when the coating medium is applied by the coating device according to the invention.

Furthermore, it is advantageous if the fiber material web is not only applied with the coating medium from one side, but also with the coating medium in two or more coating steps. In this case, the consistency and / or composition of the coating medium is adjusted differently at each coating location.

According to the invention, the conveyor belt does not necessarily have to be a press felt. Furthermore, in order to have sufficient absorption capacity for the coating medium and not to leave a mesh structure pattern on the fibrous material web, the mesh screen formed into a sufficiently fine mesh shape can be used as a transport belt. Are suitable.

Furthermore, it is advantageous if the coating device according to the invention is used in the winding area of a mesh suction roller in the mesh area. On the one hand, the coating medium penetrates particularly intensively into the fiber connection, since at this point the fiber material web still has a very loose fiber connection. On the other hand, the suction zone of the screen suction roller assists this effect.

In another aspect of the invention, a method or apparatus invention is described in the other claims. Furthermore, the contents of German Patent Applications 19747091.2 and 19747091.1 are fully incorporated by reference into the published content of the present invention.

The present invention is not limited to the above,
Various configurations can be implemented without departing from the invention.

Further features and advantages of the invention result from the following advantageous embodiments in connection with the drawings.

[0039]

FIG. 1 shows a first embodiment of a coating apparatus 10 according to the present invention. The coating device is located in the dampening area of the machine, in particular for producing a material web 12 of paper or carton. For this reason, as is evident from FIG. 1, the still wet material web 12 is received between the two mesh belts 14, 16, which ensures the bonding of the fibrous structure of the material web 12. . The material web 12 is the mesh belt 1
It is guided around the roller 18 together with the rollers 4 and 16 and contacts the surface 18a of the roller at the winding area U. Since the roller 18 is driven to rotate about its axis A in the direction of arrow P, the material web 12 engages the roller surface 18a almost without slipping during movement in the movement direction L.

On the outside of the material web 12, ie, on the side of the material web opposite the rollers, a coating mechanism 20 is provided.
The structure and function of the coating mechanism will be described below with reference to FIG.

FIG. 6 shows two mesh belts 1
The material web 12 and the coating mechanism 20 received between 4, 16 are shown. Coating mechanism 2
0 is the mesh belt 1 in the schematic sectional view of FIG.
4 and has an upstream limiting wall 20a and a downstream limiting wall 20b as viewed in the material web moving direction.
Both limiting walls 20a, 20b as well as lateral limiting walls (not shown) surround a coating chamber 22, which is open towards the mesh belt 14, to which a coating medium 24 is supplied from the outside. (Arrow M).

When viewed in the moving direction L of the material web, the distance d between the limiting walls 20a and 20b of the coating chamber is determined by the coating mechanism 2 when the material web 12 moves at a normal speed.
0, the residence time of the material web 12 in the region 0 is approximately 1 m
s to 10 ms. Further, the coating medium 24 in the coating chamber 22
300 Pa to 10 kPa, preferably 500 Pa to 5
A pressure p of kPa is applied. In this case, the pressure value is selected as follows: during the dwell time of the material web 12 in the area of the coating mechanism 20, the coating medium 24, on one side, in a sufficient amount via the mesh belt 14 through the material web 12. Is selected so as to be pressed into the area 12a near the surface of the material web and fixed therein to its fibrous structure and not otherwise penetrate into the volume or interior 12b of the material web 12.

As shown in FIG. 1, a suction device 26 is provided immediately following the coating mechanism 20 as viewed in the direction of movement L, by means of which the coating material is not coupled in a sufficient amount to the material web 12. The medium is sucked out of the material web again. Amount of coating medium sucked S
Is again supplied to the coating mechanism 20 together with the optionally sucked fibrous material after filtration. In this case, the dilution of the coating medium by the moisture drawn out of the material web is compensated, if desired, by supplying the coating medium according to the high solids content. Suction device 26
Also advantageously has a sliding contact with the mesh belt 14, thereby ensuring the required sealing action to the surrounding environment.

The roller 18 has a negative pressure zone 28 over at least a part of the winding area U. Such a roller having a negative pressure zone is known, and a description of its structure will be omitted. The negative pressure zone 28 is mainly used for dehumidifying the material web 12. Thereby, the moisture existing in the material web 12 is reduced to the surface area 12a.
The water is sucked out through the mesh net belt 16. This dries the surface area 12a, so that the coating medium 2
4 easily penetrates into the surface area and is anchored therein to the fibrous structure of the material web.

FIG. 2 shows another embodiment of the coating apparatus according to the invention, which corresponds substantially to the embodiment of FIG. Therefore, in FIG. 2, the same components as those in the embodiment of FIG.
The coating device 110 according to FIG. 2 will be described below only on the points that differ from the coating device of the embodiment of FIG.

The coating device 110 according to FIG. 2 differs from the coating device of the embodiment according to FIG. 1 in that the roller of the web of material 112 received between the mesh belts 114, 116 is: On the opposite side of 118,
A free jet nozzle coating mechanism (open jet spray coating mechanism) 120 is provided.
The coating medium, which is arranged at a distance from the mesh belt 114 or the mesh web 114 and is pre-measured, is applied to the material web 112 or the mesh web 114.

Downstream of the coating mechanism 120, an equalizing device 130 is arranged, which in the embodiment according to FIG. 2 has a scraper device 132, but is basically any other device. Can be formed by a known doctor unit or equalizing device. The equalizer 130 smoothes the applied medium 124 and removes any over-applied coating medium 124, in which case the coating medium is newly added to the feed stream M to the nozzle coating mechanism 120 after an intermediate cleaning step. Is done. According to the embodiment according to FIG.

FIG. 3 shows a further embodiment of the coating apparatus according to the invention, which corresponds substantially to the embodiment of FIG. Therefore, in FIG. 3, the same components as those in the embodiment of FIG.
In the following, only the differences between the coating apparatus 210 according to FIG. 3 and the embodiment of FIG. 1 will be described.

The coating device 210 according to FIG. 3 differs from the coating device of the embodiment according to FIG. 1 in that the material web 212 received by the mesh belts 214, 216 is applied to the rollers 218. The difference is that the coating mechanism 220 is arranged on the facing side. The coating mechanism 220 is basically configured in the same way as described for the coating mechanism 20 according to FIG. In any case, since the limiting wall of the coating mechanism 20 is in sliding contact with the surface 218a of the roller 218, this surface 218a also has
Twenty-four layers are applied.

The coating layer is conveyed in the direction of arrow P toward the winding area U based on the rotation of the roller 218 about the axis A. In this case, the coating medium 224 contacts the material web 212. Particularly when entering the winding area U, the coating medium 224 is applied to the surface 218 of the roller.
Due to the hydrodynamic pressure generated between a and the material web 212, it is pushed into the material web 212, with the intermediate position of the mesh belt 216 pushing the coating medium 224 into the volume of the material web 212. Such a large pressure value does not occur, but rather the coating medium 224
a.

Furthermore, in the embodiment of FIG. 3, no opposing roller is provided on the side of the material web opposite to the roller 218, so that it is deflected from the hydrodynamic pressure which generates the material web and thus into the volume of the material web 212. Can be prevented from entering the coating medium.

In the embodiment according to FIG. 3, the vacuum zone 228 is mainly used for sucking out excess coating medium 224 applied to the material web 212 again and supplying it to the supply stream M for the intermediate post-cleaning coating mechanism 20. . Further, in FIG. 3, a purifying device 234 for purifying the surface 218a of the roller 218 is provided. The cleaning device has a supply device 236 for applying a cleaning medium 238 to the roller surface 218a and a scraper blade 240 for removing contaminants from the roller surface 218a.

FIG. 4 shows another embodiment of the coating apparatus according to the invention, which corresponds approximately to the embodiment of FIG. Accordingly, in FIG. 4, the same components as those in the embodiment of FIG. 3 are provided with the same reference numerals increased by several hundred, that is, increased by several 300 as compared with FIG. In the following, only the differences between the coating apparatus 310 according to FIG. 4 and the coating apparatus 210 of the embodiment according to FIG. 3 will be described.

The coating apparatus 310 according to FIG. 4 differs from the coating apparatus according to the embodiment of FIG. 3 only in the following respect: a free jet nozzle coating mechanism 320 is provided instead of the coating mechanism 220. In this regard, the coating mechanism weighs and applies the coating medium 324 to the surface 318 a of the roller 318. The roller itself rotates the coating medium in the direction of arrow P based on the rotation about the axis A to form a mesh belt 314,3.
It conveys to the material web 212 received between 16. Otherwise, the embodiment of FIG. 4 corresponds to the embodiment of FIG. 3 with a vacuum zone 328 and a purifier 334.

FIG. 5 shows another embodiment of the coating apparatus according to the invention, which corresponds approximately to the embodiment of FIG. Therefore, in FIG. 5, the same components as those in the embodiment of FIG. 3 are provided with the same reference numerals increased by several 200, that is, increased by several 400 as compared with FIG. The coating apparatus 410 according to FIG. 5 will be described below only on the differences from the coating apparatus 210 of the embodiment according to FIG.

The coating device 410 according to FIG. 5 differs from the coating device 210 according to FIG.
12 in that it is supported by the screen belt 416 only on the side facing the coating roller 418. Furthermore, in the embodiment according to FIG. 5, the roller 418 has no zone corresponding to the vacuum zone 228. That is, the roller 418 is a simple deflecting roller for the material web 412, for example. Roller 41 using coating mechanism 420
The embodiment according to FIG. 5 corresponds to the embodiment according to FIG. 3 with regard to the application of the coating medium to the surface 418 a of the material 8 and to the transport of the coating medium to the material web 412. Further, a purification device 434 is provided.

Although only the embodiment in which the liquid or pasty medium is coated on one side as described above is described, the coating apparatus according to the invention can also be configured for coating from both sides. In this case, FIG. 1 and FIG.
Combinations of one of the illustrated outer coating devices with one of the inner coating devices according to FIGS. 3 and 4 are possible.

Furthermore, the solids content of the material web 12 in the area of the coating mechanism 20 is between 5% and 50%.
The solids content of the coating medium 24 is between 5 and 50 percent, preferably between 10 and 30 percent, preferably between 8 and 17 percent. In this case, the solids content of the material web is the percentage by mass of solid substances, for example fibers, fillers, etc., with respect to the total mass of the material web consisting of fibers, fillers, water and the like. The solids content of the coating medium is the percentage by weight of the solid substances, for example mineral pigments, bonding materials, auxiliaries, etc., relative to the total weight of the coating medium containing additional fluid components, mainly water. Coating media include, for example, water, mineral fillers, such as kaolin, CaCO ₃ , TiO ₂ , bonding materials, such as starch, latex, retention agents, and optical brighteners.

Furthermore, the increase in weight due to the coating of the liquid or pasty medium from side to side is preferably from 1 g / m ^{2 to} 10 g / m ² .

The coating apparatus according to the invention can be used, for example, in a "double-web former" and on the basis of its structure a film press can be used, which makes it possible to produce material webs. Increase the effectiveness of the machine.

Furthermore, as the material web is compressed in the wrapping area, the coating medium is distributed evenly over the surface of the material web without being completely impregnated, ie penetrating into the volume or interior of the material web. You. As a whole, a uniform and smooth coating is obtained with a small coating weight by means of the coating apparatus according to the invention.

FIG. 7 shows a material web (fiber material web).
P moves in the direction of the arrow 501 shown. Material web P
Moves into the press area via the mesh suction roller 503 in contact with the mesh 502. Screen suction roller 503
During the deflection process at, the material web P is fixed to the screen 502 by the suction zone 504. The first felt 505 in the press area is taken out by a suction roller 506.
Material web P from the screen 502 through the suction zone 7 and
Accept. The second felt 508 in the press section is wetted with the coating medium via the coating roller 509 and the associated doctor device 510, which together form a coating mechanism 516. After the deflection of the felt 508 on the felt guide rollers 511, the felt 508 enters the press nip or press gap together with the felt 505. Press nip is press roller 51
2 and a flexible press roller 513 having a press shoe.

The opening angle of the entry gap 514 is exaggerated in the drawings. In practice, the distance between the roller 511 and the felt 505 is only a few millimeters. In the press nip between the press rollers 512, 513, the coating medium is delivered to the material web P under pressure and with a significantly longer operating time than in the roller coating mechanism. Material web P and felt 50
After 5,508 leaves the press nip, the felt 50
8 is returned to the coating mechanism 516 again. The felt 505 and the material web P in contact therewith pass together through a press nip or gap between the rollers 512,515. After leaving the press nip, material web P
Is partially wrapped around rollers 515 and fed to another press gap or drying zone.

FIG. 8 shows another embodiment of the coating apparatus according to the present invention. In this case, in FIG. 8, the surface of the first upper felt 605, which subsequently contacts the material web, is wetted with the coating medium using the coating mechanism 617. The mesh 602, the felt 605 and the material web P are joined by a mesh roller 603. The coating medium acts on the material web P over a long section between the mesh suction roller 603 and the discharge suction roller 606.

After passing through the first press gap of the rollers 612, 613, the material web comes into contact with the unloading suction roller 622. The take-out suction roller 622 separates the material web P from the felt 605 and
The material web is transferred on 9. The felt 619 is wetted by the coating medium by the coating mechanism 618. In this case, at the felt 619 another surface of the material web contacts the coating medium. Another coating mechanism 621 wets the felt 620. Therefore, a new coating is performed on the upper surface of the material web P when passing through the next press gap. When the material web P leaves the press gap, the material web P is diverted by the suction felt guide roller 623 together with the felt 619 and supplied to the dry mesh suction roller 624. Next, the material web P is dried in the drying section 625.

FIG. 9 shows another embodiment of the coating apparatus according to the present invention. 9 similar to FIG.
In the figure, the material web P passes through two successive press roller pairs 712,713; 731,732. The coating mechanism 716 wets the lower surface of the material web P together with the felt 708. After delivering the material web P to the felt 719 using the take-out suction roller 722,
The material web P is supplied to the press gap between the press rollers 731 and 732. The felt 720 entering with the material web has been wetted by the coating medium via the coating mechanism 726. In this press gap, the upper surface of the material web P is coated. After leaving the press gap, the material web P is fed to a drying section (not shown), as already described in FIG.
Although the press gap configuration in FIG. 9 is different from that in FIG. 8, this press gap also has a sharp approach angle and an open angle which result in a long working time of the medium or a subtle opening of the coating gap. Give birth.

FIG. 10 shows another embodiment of the coating apparatus according to the present invention. In this case, an additional mesh or felt loop 827 and additional rollers 828, 829 in the area of the mesh suction roller 803 or its suction zone 804 provide the mesh 82.
The coating medium is applied to the upper surface of the material web P placed on the zero. The felt loop 827 is wetted by the coating mechanism 830. This arrangement is advantageous when it is desired to utilize the properties of the material web P and the mode of operation of the suction zone 804 at said point of the screen suction roller 803. Due to the loose fiber bonding, the coating medium can be supplied particularly optimally onto and into the material web. However, in this case, the material web is still very loose, so the application of a medium that supports the web strength is important.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment in which a coating medium is applied to a material web from outside the material web.

FIG. 2 is a diagram showing an embodiment in which a coating medium is applied to the material web from outside the material web.

FIG. 3 is a diagram showing an embodiment in which a coating medium is coated on the material web from the inside of the material web.

FIG. 4 is a view showing an embodiment in which a coating medium is applied to the material web from the inside of the material web.

FIG. 5 is a diagram showing an embodiment in which a coating medium is applied to the material web from the inside of the material web.

FIG. 6 is a schematic diagram for explaining the coating principle of the embodiment of FIG. 1;

FIG. 7 is a diagram showing a paper machine portion at a transition portion between a damping area and a press area.

FIG. 8 is a diagram showing a paper machine portion from an end of a dampening section to a start of a drying section.

FIG. 9 is a diagram showing a paper machine portion from an end of a dampening section to a drying section.

FIG. 10 shows the paper machine part at the transition between the dampening zone and the press zone, with the coating device according to the invention arranged in the area of the screen suction roller.

[Explanation of symbols]

10; 110; 210; 310; 410 Coating equipment 12; 112; 212; 312; 412, P Material web 14; 114; 214; 216; 314; 316; 41
6 Filtration belt 18; 118; 218; 318; 418 Roller 22 Coating chamber 28, 128, 228, 328 Negative pressure zone 18a; 218a; 318a; 418a Roller surface 20; 120; 220; 320; 420, 516, 61
7,618,621,716,726,830 Coating mechanism 24; 124; 224; 324; 424 Coating medium 26 Suction device 130 Equalization device 132 Scraper device 502,602,802 Filtration 505,508,602,605,619 , 620,7
08,719,720 belt 512,513; 712,713; 731,732 Press roller

 ──────────────────────────────────────────────────続 き Continuation of the front page (31) Priority claim number 19823739.1 (32) Priority date May 27, 1998 (33) Priority country Germany (DE) (72) Inventor Peter Galina Hellebre, Germany Hittingen Stallenweg 3 (72) Inventor Michael Trefts United States of America Wisconsin Up Luton Big Bend Drive 2901 (72) Inventor Volker Schmidt-Lower Germany Heidenheim Al Tenheimstrasse 3

Claims (39)

[Claims] 1. A material web (12; 112; 21) which has been manufactured and which is still moist, in particular made of paper or carton.
2; 312; 412) in a liquid or paste medium (2
4; 124; 224; 324; 424) for direct or indirect application (10; 110; 210; 31).
0; 410), the material web (12; 112; 212; 31) in the winding area (U) over a part of the circumferential direction.
2; 412) (18; 118; 21)
8; 318; 418) and the material web (12; 112).
Coating mechanism (20; 120; 220;) for applying a liquid or paste-like medium (24; 124; 224; 324; 424) to the surface (218; 318; 418a) of the roller (218; 318; 418). 3
20; 420) and a coating mechanism (20; 120;
220; 320; 420) and the material web (12; 11).
2; 212; 312; 412) and at least one mesh belt (14; 114;) supporting the material web (12; 112; 212; 312; 412).
216; 316; 416) and the coating medium (24; 124; 224; 324; 424).
Is the material web (12; 112; 21) in the winding area (U) of the rollers (18; 118; 218; 318; 418).
2; 312; 412), in particular for the dampening area of a machine for producing a web of material consisting of paper or carton. 2. The coating mechanism (20; 120) comprises:
The material web (1) on the opposite side of the rollers (18; 118)
2; The coating apparatus according to claim 1, which is arranged on the 112) side. 3. Coating device according to claim 1, wherein the coating mechanism (20) is in sliding contact with the mesh belt (14). 4. The coating apparatus according to claim 1, wherein the coating mechanism is arranged at a distance from the mesh belt. 5. A removal device (26) for removing, preferably sucking, excess coating medium (24) from the material web (12) is arranged downstream, preferably immediately downstream, of the coating mechanism (20). The coating device according to any one of claims 1 to 4, wherein the coating device is formed. 6. An equalization downstream of the coating mechanism (120) for equalizing the coating medium (124) and, if desired, for removing excess coating medium (124) from the material web (12). Equipment (13
6. Coating device according to claim 1, wherein 0) is arranged. 7. The coating device according to claim 6, wherein the equalizing device has a scraper device. 8. The coating mechanism (220; 320; 4).
20), the surface (21) of the rollers (218; 318; 418) guiding the material webs (212; 312; 412).
8a; 318a; 418a) to the coating medium (22
4; 324; 424). 9. Coating mechanism (220; 42)
0) is the surface (218) of the roller (218; 418).
A coating device according to claim 8, wherein the coating device is in sliding contact with a; 418a). 10. The coating apparatus according to claim 8, wherein the coating mechanism (320) is spaced from a surface (318a) of the roller (318). 11. Rollers (18; 118; 218; 31)
11) Coating device according to claim 1, wherein 8) has a vacuum zone (28; 128; 228; 328) over at least a part of the winding area (U). . 12. The coating system according to claim 1, wherein the coating mechanism has a coating chamber through which the coating medium flows under pressure.
The coating apparatus according to any one of the preceding claims. 13. In the coating chamber (22):
300 Pa to 10 kPa, preferably 500 Pa to 5
13. Coating device according to claim 12, wherein the pressure (p) of kPa is controlled. 14. The working time of the coating medium (24) flowing out of the coating chamber (22) is 1 ms.
14. The coating apparatus according to claim 12, wherein the time is from 10 to 10 ms. 15. Coating mechanism (20; 120; 2)
20; 320; 420), the coating medium (24;
124; 224; 324; 424) is metered and supplied. 16. The coating apparatus according to claim 1, wherein the coating mechanism is a free jet nozzle coating mechanism. 17. The coating device according to claim 1, wherein the web of material is received between two mesh belts. 18. The coating apparatus as claimed in claim 1, wherein the radius (r) of the roller has a value between 200 mm and 1200 mm. 19. The coating apparatus according to claim 1, wherein the solids content of the paper web (12) is between 5 and 50%, preferably between 8 and 17%. 20. The coating medium (24) having a solids content of 5 to 50%, preferably 10 to 50%.
1 to 1 to 30 percent.
The coating apparatus according to any one of claims 9 to 9. 21. A paper machine equipped with a device for applying a liquid or pasty coating medium to a moving material web (P) consisting of paper or carton, comprising a dampening section, a pressing section and a drying section. And a moving endless breathable belt (505,
602, 605, 619, 705, 719, 802), at least one for the material web (P) to be produced.
One transport device and at least one coating mechanism (516, 617, 618, 621, 716, 16) for applying a coating medium to the material web side opposite the transport device.
726, 830), the coating mechanism comprises a moving endless breathable conveyor belt (508, 605, 619, 620, 708, 708) for applying the coating medium to the material web.
720, 827). 22. A roller coating mechanism for applying a coating medium to a conveyor belt.
618, 621, 716, 726, 830) are provided. 23. A roller coating mechanism (516, 6).
17, 618, 621, 716, 726, 830)
23. The paper machine according to claim 22, comprising a single roller (509). 24. A roller coating mechanism (516, 6).
17, 618, 621, 716, 726, 830)
23. The paper machine according to claim 22, formed from a number of rollers. 25. A conveyor belt (508, 605, 61)
The paper machine according to any one of claims 21 to 24, wherein (9,620,708,720,827) is formed from press felt. 26. A conveyor belt (508, 605, 61)
The paper machine according to any one of claims 21 to 24, wherein (9, 620, 708, 720, 827) is formed from a mesh. 27. A method for applying a liquid or pasty coating medium to a moving material web (P) consisting of paper or carton, the material web (P) being dampened in a dampening zone of a paper or cardboard machine. Forming and moving an endless, preferably breathable belt (505, 602, 605, 619, 705, 719,
802) and transferring the coating medium from the moving surface to the still wet web of material in the direction of web movement, wherein the coating medium is moved at least by an endless, breathable material. One conveyor belt (508, 605, 6
19, 620, 708, 720, 827) to the material web (P). 28. At least one conveyor belt (50)
8,605,619,620,708,720,82
28. The method according to claim 27, wherein 7) is a press felt. 29. At least one conveyor belt (50)
8,605,619,620,708,720,82
28. The method of claim 27, wherein 7) is a screen. 30. Material web (P) during coating
30. The method according to any one of claims 27 to 29, wherein the is contacted with the screen (502, 602, 802) of the screen area. 31. Material web (P) for coating
The felt in the press area (505, 605, 619, 7
31. The method according to any one of claims 27 to 30, wherein said method is contacted with the method of any one of claims 27 to 30. 32. The method as claimed in claim 27, wherein the coating medium is applied to only one side of the material web (P). 33. The method according to claim 27, wherein the coating medium is applied to both sides of the material web. 34. The method according to claim 27, wherein the coating medium is applied to the web of material (P) upstream of the first press (512, 513) in the press section. . 35. The method as claimed in claim 27, wherein the coating medium is applied to the material web downstream of the first press in the press section. . 36. The method as claimed in claim 27, wherein the coating medium is applied to the material web in a winding area of a screen suction roller in a screen area. . 37. The coating medium is applied to at least one side of the material web (P) in a dampening zone.
37. The method according to any one of claims 36 to 36. 38. The material web (P) is applied to the material web (P) by means of both felts (519, 520) of a double felt press in the press area.
The method according to any one of the preceding claims. 39. The method according to claim 27, wherein the coating media applied at different locations have different compositions.