Scraper and coating device

Abstract

Scraper, in particular edge scraper, for cleaning a moving surface of a machine for manufacturing or processing a fibrous web and a coating device, wherein the scraper has a scraper body and a scraper tip, the scraper being fastenable at the scraper body on a holding device, the scraper tip being for contacting the moving surface, characterized in that at least one delivery line for a lubricating fluid is provided in or on the scraper, wherein the at least one delivery line ends in a distributor for distributing the lubricating fluid over the length of the scraper, and wherein the distributor opens at the scraper tip so that the lubricating fluid can be output.

Description

Technical Field

[0001] The present invention relates to a scraper, particularly an edge scraper, for cleaning the moving surfaces of machines used to manufacture or process fiber webs, and to a coating apparatus, particularly a film press. Background Technology

[0002] Various types of rollers are used in the manufacture or processing of fiber webs, such as paper webs or paperboard webs. Many rollers become dirty during operation and must be cleaned or replaced.

[0003] A specific example is a coating apparatus for indirectly coating fiber webs, such as a so-called film press. Here, a film of the applied medium (e.g., a starch solution) is pre-dispensed onto a conveyor roller and then conveyed onto the fiber web in a conveying press zone. However, since the fiber webs typically have different widths depending on the batch produced, the problem arises that the width of the film pre-dispensed onto the rollers must match the width of the web. To achieve this, so-called edge scrapers are known from the prior art. These scrapers are positioned at the edge of the conveyor roller and scrape off the applied medium there. These scrapers are movably mounted, thereby allowing the apparatus to match the varying widths of the material webs. Such edge scrapers are described, for example, in documents DE102004039162A1 or CH 712 248.

[0004] Furthermore, according to existing technologies such as DE202017101177 U1, a blowing or spraying device is provided to keep the scraper and its surrounding environment clean or to achieve a lubricating effect.

[0005] However, a recent trend has emerged to replace traditional rubber rollers with rollers featuring polyurethane surfaces in membrane presses and similar devices. Here, polyurethane is more sensitive to the lack of lubrication of the doctor blade compared to rubber. Furthermore, the increasing operating speed of membrane presses often leads to insufficient lubrication of the doctor blade by the spraying device, resulting in damage to the roller surface. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a scraper that overcomes the difficulties of the prior art. In particular, the object of the present invention is to provide improved lubrication for scrapers (especially edge scrapers for coating devices). Furthermore, the object of the present invention is to maintain less resource consumption when using and applying the scraper.

[0007] These tasks are completely solved by the scraper according to the invention and the coating device according to the invention.

[0008] Regarding the doctor blade, this task is solved by a doctor blade, particularly an edge doctor blade, used to clean the moving surfaces of machines used to manufacture or process fiber webs. The doctor blade has a blade body and a blade tip, the blade body being securely fastened to a retaining device, and the blade tip for contacting the moving surface. According to the invention, at least one delivery line for lubricating fluid is provided in or on the doctor blade, wherein the at least one delivery line terminates at a distributor for distributing lubricating fluid along the length of the doctor blade, and wherein the distributor opens at the blade tip, allowing the lubricating fluid to be output.

[0009] The lubricating fluid can be, in particular, lubricating water.

[0010] The moving surface is typically the surface of a roller, such as a conveyor roller. Alternatively, however, the moving surface can also be a belt, such as a conveyor belt or a pressure belt. Here, the invention is not limited to application at a specific surface.

[0011] Fiber webs can be, in particular, paper webs, paperboard webs, pulp webs or nonwoven webs (“Nonwoven”).

[0012] Compared to existing technologies, the scraper according to aspects of the invention is configured such that lubricating fluid is guided through at least one delivery line extending wholly or partially within the scraper itself, or wholly or partially directly on the outside of the scraper. These delivery lines terminate at a distributor for distributing lubricating fluid along the length of the scraper. This is for uniformly distributing the lubricating fluid along the length of the scraper, thereby ensuring uniform lubrication. The distributor opens at the scraper tip, allowing lubricating fluid to be output there across the entire width of the scraper, or at least substantially across the entire width of the scraper. Areas thereon where no lubricating fluid is distributed or from which no lubricating fluid is output may, if necessary, be provided only in the edge regions of the scraper. This can be advantageous, for example, to prevent lateral output of lubricating fluid on the moving surface.

[0013] This invention enables the direct application of lubricating fluid to the tip of the scraper that contacts the surface. This allows for very simple and thorough lubrication of the scraper. In known nozzles, most of the lubricating water ends up unused in the environment, while in the scraper according to this invention, all the lubricating fluid is used for lubrication. In this way, significant amounts of lubricating water can be saved during facility operation, which is not only economically advantageous but also desirable for ecological reasons.

[0014] In an advantageous embodiment, multiple delivery lines for lubricating fluid may be provided in or on the scraper, terminating at a distributor, and these delivery lines are arranged, preferably evenly, along the length of the scraper. Thus, for example, the delivery lines may be arranged at intervals of 5 cm, 8 cm, or 10 cm. This description should also include embodiments in which a single common delivery line is initially provided within the area of ​​the scraper body, then divided into multiple lines, which subsequently terminate at the distributor at the aforementioned intervals.

[0015] Advantageously, the dispenser can be configured to include or consist of a dispensing groove that extends along the length of the scraper and opens at the tip of the scraper. An advantage of this embodiment is that the dispensing groove can be manufactured very easily in terms of manufacturing technology.

[0016] In a simplified implementation, the dispenser consists only of the dispensing tank. Lubricating fluid is then guided into the dispensing tank from one or more delivery lines. From there, the liquid can fill the dispensing tank and thus be dispensed along the length of the scraper.

[0017] The scraper can, for example, be placed against a moving surface such that the open side of the groove points toward the surface, so that lubricating fluid can be output to the surface.

[0018] Alternatively, the distribution groove can be completely or partially filled with a porous material, particularly porous ceramic materials, open-cell polymer foam, or foamed metal. Suitable porous structures can also be produced by thermal spraying or sintering. This material enables uniform distribution of fluid along its length, as well as uniform delivery of lubricating fluid to the surface. In particular, the porous material can be configured to contact the moving surface when the scraper is used as intended. Furthermore, this material may be advantageous because the already thin scraper tip is further weakened by introducing the groove. Completely or partially filling the groove provides additional reinforcement to the scraper tip.

[0019] Another feasible approach is to manufacture this porous structure by creating an intermediate layer in a manufacturing process that utilizes materials that subsequently volatilize or dissolve using common production techniques. Once additives such as salts or plastics (which decompose at lower temperatures compared to the remaining material of the structure) are removed, the porous structure is formed.

[0020] The advantage of foamed materials or other porous structures is that they can be manufactured relatively simply and inexpensively. However, in the case of foams, the open surfaces cannot be clearly defined, and there is a possibility of adverse capillary effects. Therefore, the working medium from the environment can be absorbed if necessary.

[0021] In the case of fine-pore structures (such as those formed in ceramics by thermal spraying), higher pressure is required to deliver the lubricating medium. Additionally, surfaces on which there should be no output (e.g., on the sides) must be sealed if necessary. However, in alternative embodiments, the dispenser can also be implemented in other ways without using dispensing channels. For example, when applying the appropriate 3D printing method (additive manufacturing), a transverse dispensing portion can be provided inside the scraper, with an opening extending from this transverse dispensing portion towards the tip of the scraper. More complex structures are also feasible. This allows the creation of fine channels within the middle layer of the scraper using a 3D printing process. Thus, for example, the open surfaces in the area of ​​the scraper contact can be controlled, and the cross-section of the channels can be arbitrarily changed, thereby allowing for targeted local control of capillary effects and flow capacity. Connecting devices for one or more delivery lines for the lubricating medium or hydraulic fittings can also be printed simultaneously. Therefore, it is particularly possible to achieve a scraper having one or more connecting devices on which the delivery lines are connected to the dispenser, wherein the system of connecting devices and channels is implemented as a single unit.

[0022] Such printed structures can be made, for example, from metals, thermoplastics, and / or short-fiber reinforced thermosetting plastics using UV curing. In a particularly advantageous embodiment, the doctor blade can be modularly constructed, comprising a base module providing the doctor blade body and a wear module including the doctor blade tip. The base module and the wear module are releasably connected to each other.

[0023] Typically, this type of scraper is used only in the machine until the scraper tip wears down to the point where it can no longer achieve sufficient cleaning. Then, the entire scraper is discarded. The scraper body, however, can still be used. The advantage of this modular division of the scraper is that instead of replacing and discarding the entire scraper, only the worn modules need to be replaced and discarded, while the base module can remain in the machine for a longer period. The worn modules can advantageously occupy up to 50% of the scraper height, especially less than 30%, preferably 20% or less. In the case of an exemplary scraper height of, for example, 75mm, implementing a worn module with a height of 15mm may be sufficient. This results in only about one-fifth of the waste material being generated upon replacement. Here, the modules can be connected to each other, for example, by force-locking or form-locking. Simple threaded connections are often suitable.

[0024] This modular construction of the scraper is particularly advantageous when combined with the following implementation, wherein initially only a common feed line is provided in the area of ​​the scraper body, and then it is divided into multiple lines, which then terminate at the distributor at the stated spacing. Here, line guidance is advantageously implemented such that multiple lines are formed on the wear module. Thus, when replacing the wear module, only one line connection needs to be ensured, i.e., the common feed line. Here, the base module can be constructed entirely or at least partially of metal. Alternatively or additionally, the wear module can be constructed at least partially of polymer materials and / or ceramics. The dimensions of the scraper are characterized by its length (in the machine's transverse direction CD), its height, and its thickness.

[0025] The scraper according to an embodiment of the invention can extend along the entire CD direction of the machine and has a length of up to 10m or more. However, when used as an edge scraper, the length is typically less than 1m. In particular, it is possible for the scraper to have a length between 5cm and 40cm, especially between 10cm and 30cm.

[0026] In an exemplary embodiment, the height of the scraper can be between 50 mm and 200 mm, particularly between 75 mm and 150 mm.

[0027] The thickness of the scraper, especially the tip, is significantly smaller in comparison, although scrapers according to different embodiments of the invention can also be thicker than common scrapers. Nevertheless, the thickness of the scraper is generally less than 10 mm, especially 5 mm or less.

[0028] Regarding the apparatus, this task is accomplished by a coating device, particularly a membrane press, for indirectly applying a liquid or paste-like medium to a traveling fiber web, wherein the coating device includes at least one conveying roller for transferring the liquid or paste-like medium onto the material web. According to the invention, the coating device is equipped with a scraper for cleaning at least one of the conveying rollers, implemented according to aspects of the invention.

[0029] In particular, the coating apparatus may be configured to have edge scrapers on the edges of the drive side and the guide side of the conveyor roller, wherein the two edge scrapers are implemented according to aspects of the invention.

[0030] Here, the scraper, especially the edge scraper, can be implemented as a drag-type scraper or a piercing scraper. Both of these variations are feasible within the scope of this invention.

[0031] It can now be achieved more simply by improving lubrication, with the surface of the conveyor roller being constructed entirely or partially of polyurethane. However, the scraper according to aspects of the invention can also be used on surfaces or conveyor rollers made of other materials, such as rubber, metal surfaces, or composite materials.

[0032] Different feasible solutions can be considered for regulating or controlling the amount of lubricating fluid supplied to the scrapers. Thus, it is possible to have a common valve device that controls the fluid flow to both edge scrapers, or to equip each edge scraper with its own valve device for controlling the fluid flow. While the solution with a valve device is more advantageous and perfectly adequate for typically similar contamination conditions on both the guide and drive sides, variations with independent valve devices allow for more precise delivery of lubricating fluid.

[0033] Furthermore, the modular construction of the scraper, consisting of a base module and a wear module, independent of lubrication factors, itself embodies the inventive concept. This inventive concept can be described in the following embodiments, wherein the terminology and limitations used to date continue to be used: Option 1: A scraper, particularly an edge scraper, used to clean the moving surfaces of machines used to manufacture or process fiber webs, wherein the scraper has a scraper body and a scraper tip, the scraper body being securely fastened to a retaining device, the scraper tip being used to contact the moving surface, wherein the scraper is modularly constructed and has a base module providing the scraper body, the scraper also having a wear module including the scraper tip, wherein the base module and the wear module are releasably connected to each other.

[0034] Option 2: The scraper according to Option 1, wherein the base module is made entirely or partially of metal, while the wear module is constructed at least partially of polymer material and / or ceramic.

[0035] Option 3: A scraper according to either Option 1 or Option 2, wherein the wear module accounts for at most 50% of the scraper height (H), especially less than 30% of the scraper height (H), preferably 20% or less.

[0036] Option 4: A scraper according to any of the aforementioned options, wherein the scraper has a length between 5cm and 40cm, particularly between 10cm and 30cm.

[0037] Option 5: A scraper according to any of the preceding options, wherein the base module and the wear module are force-locked and / or form-locked connected to each other, particularly by means of one or more threaded connections.

[0038] Option 6: A coating apparatus, particularly a membrane press, for indirectly applying a liquid or paste-like medium to a traveling fiber web, wherein the coating apparatus includes at least one conveying roller for conveying the liquid or paste-like medium onto the material web, characterized in that the coating apparatus has at least one scraper for cleaning the conveying roller, the scraper being implemented according to any one of Options 1 to 5.

[0039] Scheme 7: The coating apparatus according to Scheme 6 is characterized in that the coating apparatus has edge scrapers (1) on the edge of the drive side and the edge of the guide side of the conveying roller (10), wherein the two edge scrapers (1) are implemented according to any one of Schemes 1 to 5. Attached Figure Description

[0040] The invention is described below with reference to the accompanying drawings. However, the invention is not limited to the embodiments shown herein. The drawings illustrate in detail: Figure 1 A schematic cross-sectional view of a scraper according to an aspect of the invention is shown; Figure 2 A top view of the scraper tip according to another aspect of the invention is shown; Figures 3a to 3e The scraper tips according to different aspects of the present invention are shown respectively; Figure 4 A schematic cross-sectional view of a scraper according to another inventive concept is shown; Figure 5 A schematic cross-sectional view of a scraper according to another inventive concept is shown.

[0041] Detailed Implementation Plan

[0042] Figure 1 A scraper 1 according to an aspect of the invention is shown. Here, the scraper tip 3 is conceived as resting against the moving surface 10. The scraper body 2 can be fastened, for example, clamped to a scraper holder. The height H of such a scraper 1 can be, for example, between 5 cm and 15 cm. In the embodiment shown here, a delivery line 4 is provided that extends entirely inside the scraper 1. Alternatively, the delivery line 4 can also extend entirely or partially outside the scraper 1. The delivery line 4 terminates at a distributor 5, which can distribute lubricating fluid along the length L of the scraper 1. In this example, the distributor 5 is implemented as a distribution groove 5 extending along the length L of the scraper 1. The distribution groove 5 is open at the scraper tip 3 to allow the output of lubricating fluid. Figure 1 The scraper 1 shown is implemented in a modular manner. The scraper includes a base module 7 and a wear module 8. Here, the wear module 8 includes a scraper tip 3, which undergoes continuous wear during the operation of the scraper 1. If the scraper 1 can no longer properly perform its task due to such wear, the entire scraper 1 should usually be replaced. Based on the modular structure, it is now sufficient to replace only the wear module 8, while the base module 7 can continue to be used. The base module 7 can be made of metal, for example, while the wear module 8 can be made entirely or partially of plastic.

[0043] Figure 2 A top view of the scraper tip 3 is shown, which can be used, for example, as... Figure 1In the scraper 1, two conveying lines 4 are provided along the length L of the scraper 1, and their ends 6 lead into the distributor 5. More than two conveying lines 4 can be provided, especially in longer scrapers 1. The distributor 5 is implemented as a distribution groove 5. It is generally advantageous to use such a distribution groove 5, such as... Figure 2 As shown, the longitudinal end of the distribution groove 5 is closed to prevent the output of lubricating fluid. Figure 2 In the scraper 1 shown, when viewed in the thickness direction D of the scraper 1, the distribution groove 5 is not located in the middle. Instead, when viewed in the travel direction LR of the moving surface 10, the front wall 9a is thinner than the rear wall 9b. This can be advantageous because the lubrication effect from the lubricating fluid in the rear part of the scraper tip 3 is significantly stronger than that from the lubricating fluid in the front part, thus causing a lack of lubrication where the front wall 9a is thicker.

[0044] Figures 3a to 3e Different alternative embodiments of the scraper tip 3 according to different aspects of the present invention are shown. It should be clearly shown that various embodiments can be implemented with respect to the scraper 1 according to these aspects of the present invention. However, the present invention is not limited to these embodiments.

[0045] Figure 3a As shown Figure 2 The scraper tip 3. Here, the scraper tip 3 rests against the traveling surface 10, such as the conveyor roller 10 of a membrane press. Figure 3b The following is an addition: Figure 3a The tip 3 of the scraper, and the dispenser 5, are implemented in the form of a dispensing groove 5, which is completely or at least partially filled with a porous material 11. This porous material 11 can be implemented, for example, in the form of ceramic or plastic foam, and improves the uniform distribution of the cleaning fluid along the length of the scraper. Additionally, the porous material 11 stabilizes the scraper tip 3. Because the front wall 9a is implemented relatively thinly, weak points may form in the front wall. This can be avoided by using the porous material 11. Figure 3c Implementation plan and Figure 3a The difference in the implementation scheme is that the front wall 9a is implemented in the form of a lip 12. This lip can be made of a different material than the scraper 3 or the wear module 8 and can be fixed thereto. The lip 12 is only used to prevent the lubricating fluid from being output against the direction of travel LR of the surface 10 and has almost no cleaning effect. Here, for example, the lip 12 can be designed such that it is worn in a targeted manner during the break-in period until it is precisely sealed against the surface 10 at the predetermined scraper positioning point.

[0046] and Figure 3dAn alternative embodiment is shown in which the dispenser 5 is implemented not as a dispensing groove, but as a built-in dispensing channel 5: this dispensing channel 5 guides the lubricating fluid through multiple channels or also through slits to one or more output openings 13. This built-in structure can be reliably manufactured, even with more complex geometries, using 3D printing processes.

[0047] at last, Figure 3e Show Figure 3b A variation of the scraper tip 3 is described. Here, the dispenser 5 is also implemented as a dispensing groove 5 filled with porous material 11. However, the opening of the groove does not point towards the traveling surface 10. Instead, the groove is arranged at an angle, and the opening 13 is located just before the first contact point between the scraper tip 3 and the surface 10. This embodiment does not have a front wall 9a, thereby avoiding possible weak points. Therefore, in an alternative embodiment, the porous material 11 can also be omitted.

[0048] Figure 4 A scraper 1 according to another concept of the present invention is shown. Here, Figure 4 The scraper 1 shown is implemented modularly. The scraper includes a base module 7 and a wear module 8. Here, the base module 7 provides the scraper body 2, to which the scraper 1 is secured. Here, the scraper tip 3 rests against the moving surface 10. The wear module 8 includes the scraper tip 3, which undergoes continuous wear during the operation of the scraper 1. If the scraper 1 can no longer properly perform its task due to this wear, the entire scraper 1 must typically be replaced. Based on the modular structure, it is now sufficient to replace only the wear module 8, while the base module 7 can continue to be used. The base module 7 can be made of metal, for example, while the wear module 8 can be made wholly or partially of plastic. Figure 4 In the scraper 1 shown, the base module 7 and the wear module 8 are exemplaryly connected by a dovetail joint. However, various other connection possibilities are also conceivable, such as threaded connections. In the embodiment shown, the scraper 1 does not have a mechanism for guiding, distributing, or delivering fluid. This scraper 1 can also be used, for example, with conventional lubrication devices (e.g., lubrication nozzles). Depending on the application, it can also be used in principle without additional lubrication. The height H of this scraper 1 can be, for example, between 5 cm and 15 cm.

[0049] Figure 5 A scraper is shown, wherein the distributor 5 includes a channel system 16. Here, one or more coupling devices 15 are integrated with the distributor or channel system 16. The conveying line 4 can be connected to the distributor 5 via these coupling devices 15. Figure 5In one implementation, the channel system 16 is entirely located within the wear module 8 and is connected to the transport line 4 via a coupling device 15, which extends within or on the base module 7. It is possible that the distributor 5, along with the channel system 16 or even the entire wear module 8, is manufactured using additive manufacturing processes. This allows for considerable freedom in the type, size, and shape of the channel 16.

[0050] List of reference numerals

[0051] 1. Scraper

[0052] 2. Scraper body

[0053] 3. Scraper tip

[0054] 4. Conveyor Line

[0055] 5 Distributors

[0056] 6. End of the conveyor line

[0057] 7 Basic Modules

[0058] 8 Wear Module

[0059] 9a Anterior wall

[0060] 9b Rear wall

[0061] 10. Moving surfaces

[0062] 11 Porous Materials

[0063] 12 lips

[0064] 13 Output opening

[0065] 15. Connecting device

[0066] 16-channel system

[0067] D. Thickness of the scraper

[0068] H scraper height

[0069] L scraper length

[0070] LR surface travel direction

Claims

1. A scraper (1), said scraper being used to clean the moving surface (10) of a machine used to manufacture or process fiber webs, wherein, The scraper (1) has a scraper body (2) and a scraper tip (3), the scraper (1) being fastened to a retaining device at the scraper body, the scraper tip being used to contact the moving surface (10), characterized in that at least one delivery line (4) for lubricating fluid is provided in or on the scraper (1), wherein the at least one delivery line (4) terminates at a distributor (5) for distributing lubricating fluid along the length (L) of the scraper (1), wherein the distributor (5) is open at the scraper tip (3) so that lubricating fluid can be output, wherein the distributor (5) includes a distribution groove extending along the length direction (L) of the scraper (1) and open at the scraper tip (3), and wherein the distribution groove is completely or partially filled with a porous material (11).

2. The scraper (1) according to claim 1, characterized in that, A plurality of delivery lines (4) for lubricating fluid are provided in or on the scraper (1), the plurality of delivery lines terminating in the distributor (5).

3. The scraper (1) according to claim 1, characterized in that, The porous material (11) is a porous ceramic material or an open-cell foam material.

4. The scraper (1) according to claim 3, characterized in that, When the scraper (1) is used as specified, the porous material (11) is in contact with the moving surface (10).

5. The scraper (1) according to claim 1 or 2, characterized in that, The dispenser (5) includes a system of channels extending inside the scraper (1).

6. The scraper (1) according to claim 5, characterized in that, The scraper (1) has one or more connecting devices, and the conveying line (4) is connected to the distributor (5) at the connecting device, wherein the connecting device (15) is implemented as an integral part of the channel system.

7. The scraper (1) according to claim 1 or 2, characterized in that, The scraper (1) is modularly constructed and has a base module (7) that provides the scraper body (2), and the scraper (1) also has a wear module (8) that includes the scraper tip (3), wherein the base module (7) and the wear module (8) are connected to each other in a releasable manner.

8. The scraper (1) according to claim 7, characterized in that, The base module (7) is made entirely or partially of metal, while the wear module (8) is at least partially constructed of polymer materials and / or ceramics.

9. The scraper (1) according to claim 7, characterized in that, The wear module (8) occupies up to 50% of the scraper height (H).

10. The scraper (1) according to claim 1 or 2, characterized in that, The scraper (1) has a length (L) between 5 cm and 40 cm.

11. The scraper (1) according to claim 1, characterized in that, The scraper (1) is an edge scraper.

12. The scraper (1) according to claim 2, characterized in that, The multiple conveying lines are arranged along the length (L) of the scraper (1).

13. The scraper (1) according to claim 12, characterized in that, The multiple conveying lines are evenly distributed along the length (L) of the scraper (1).

14. The scraper (1) according to claim 6, characterized in that, The connecting device (15) and the system of the channel are manufactured using an additive manufacturing process.

15. The scraper (1) according to claim 9, characterized in that, The wear module (8) is less than 30% of the scraper height (H).

16. The scraper (1) according to claim 9, characterized in that, The wear module (8) occupies 20% or less of the scraper height (H).

17. The scraper (1) according to claim 1 or 2, characterized in that, The scraper (1) has a length (L) between 10 cm and 30 cm.

18. A coating apparatus for indirectly applying a liquid or paste-like medium onto a traveling fiber web, wherein, The coating apparatus includes at least one conveying roller for conveying a liquid or paste-like medium onto a fiber web, characterized in that the coating apparatus has at least one scraper (1) for cleaning the conveying roller, the scraper being implemented according to any one of claims 1 to 17.

19. The coating apparatus according to claim 18, characterized in that, The coating device has scrapers (1) on the edge of the drive side and the edge of the guide side of the conveying roller, respectively, wherein the scrapers are implemented as edge scrapers.

20. The coating apparatus according to claim 19, characterized in that, They are provided with a common valve device that controls the fluid flow of the two edge scrapers, or each edge scraper is equipped with its own valve device for controlling the fluid flow.

21. The coating apparatus according to any one of claims 18 to 20, characterized in that, The surface (10) of the conveyor roller is entirely or partially constructed of polyurethane.

22. The coating apparatus according to claim 18, characterized in that, The coating device is a membrane press.

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