Coating system for metal strips and method for producing metal strips partially coated on one side

Abstract

The invention relates to a coating system for metal strips, consisting of: a coating roll,an application device for the coating material,a mask strip guided over the coating roll by means of deflection rolls, the mask strip being configured endlessly,a strip guide for the metal strip running over the coating roll.

Description

Other advantages and configurations of the invention will be explained in more detail with the aid of the schematic drawings, in which:

FIG. 1 shows a coating system with a coating nozzle and

FIG. 2 shows a coating system with a melt bath.

Parts corresponding to one another are provided with the same reference numerals in all the figures.

FIG. 1 shows a coating system 1, in which the metal strip 20 to be partially coated is guided together with the mask strip 10 over the coating roll 2. The application device contains a coating nozzle 3 extending in the axial direction with respect to the coating roll 2. As can be seen from FIG. 1, for example, liquid tin as coating material is applied above the coating roll 2, i.e. immediately after the mask strip 10 comes together with the metal strip 20. The mask strip 10 has openings at the positions where the coating is intended to be applied onto the metal strip 20. The mask strip 20 is made from a flexible material, which is not wetted by the coating material.

The metal strip 10 to be coated is guided over the coating roll 2 and clamped with the required strip tension by a deflection roll as a strip guide 21, so as to ensure that no liquid coating material reaches the rear side of the metal strip 20. The running direction L of the metal strip 20 and of the mask strip 10 is respectively denoted by an arrow.

The mask strip 10 is likewise prestressed with the required tension by a deflection-tension roll 12, so that no coating material can enter the gap between the metal strip 20 and the mask strip 10. The forward feed rates of the metal strip 20 and of the mask strip 10 are correspondingly adapted to one another by means of the driving mask strip roll 11, so that no relative movement takes place between the metal strip 20 and the mask strip 10.

The mask strip 10 is guided endlessly over the driving mask strip roll 11, the deflection-tension roll 12 and two further mask strip deflection rolls 13. In the case of a material not wettable by the melt for the mask strip 10, an additional cleaning device is superfluous.

Since in the case of metal layers containing tin, the desired end thickness of the coating is much less than the thickness of the material originally applied, excess tin is removed over two stages in order to adjust the desired layer thickness. The scraper instrument provided for this consists of a scraper element 5 and a blower nozzle 6.

FIG. 2 represents another example of a coating system 1 with a melt bath 4. Instead of with a coating nozzle 3, the one-sided tin plating is now carried out with a coating roll 2 immersed in a melt bath 4. This consists of ceramic solid material, so that no coating material adheres on the surface of the coating roll 2.

The coating roll 2 is only partly immersed in the melt bath 4. The metal strip 20 to be coated on one side is guided through the melt bath 4 while bearing tightly on the coating roll 2, in order to avoid undesired ingress of the metal melt on the rear side of the metal strip 20.

In the coating system 1 represented in FIG. 2, the axis of the coating roll 2 is not immersed into the melt bath 4. In this way, the coating roll 2 is brought only partially in contact with the melt, and the metal strip 20 to be coated and the mask strip 10 bear on one another only in this contact region, in the region of the scraper element 5 and the blower nozzle 6.

Further process units may be connected upstream, for example a chemical or mechanical instrument for cleaning the strip surface before coating. There may likewise be further process units downstream, for example an oven for heat-treating the applied metal layer.

LIST OF REFERENCES

• 1 coating system
• 2 coating roll
• 3 coating nozzle
• 4 melt bath
• 5 scraper element
• 6 blower nozzle
• 10 mask strip
• 11 driving mask strip roll
• 12 deflection-tension roll
• 13 mask strip deflection roll
• 20 metal strip
• 21 strip guide for metal strip
• L running direction

Claims

1. Coating system (1) for metal strips, consisting of: a coating roll (2),an application device (3, 4, 5, 6) for the coating material,a mask strip (10) guided over the coating roll (2) by means of deflection rolls (11, 12, 13), the mask strip (10) being configured endlessly,a strip guide (21) for the metal strip (20) running over the coating roll (2).

2. Coating system according to claim 1, characterized in that the surface of the coating roll (2) is shaped concavely or conically toward the roll middle.

3. Coating system according to claim 1, characterized in that at least the surface of the coating roll (2) consists of a material which is not wettable by the coating material.

4. Coating system according to claim 1, characterized in that at least the surface of the mask strip (10) consists of a material which is not wettable by the coating material.

5. Coating system according to claim 1, characterized in that the application device (3, 5, 6) comprises a slotted coating nozzle (3) extending in the direction toward the coating roll (2).

6. Coating system according to claim 1, characterized in that the application device (4, 5, 6) comprises a melt bath (4), in which the coating roll (2) is partly immersed.

7. Coating system according to claim 6, characterized in that the axis of the coating roll (2) immersed into the melt bath (4) is arranged over the melt bath surface.

8. Coating system according to claim 1, characterized in that the application device (3, 4, 5, 6) has a scraper element (5) and/or a blower nozzle (6).

9. Coating system according to claim 1, characterized in that at least the application device (3, 4, 5, 6) is arranged in a closed housing with protective gas.

10. Method for producing metal strips (20) partially coated on one side by means of a coating system (1) according to claim 1, characterized in that a metal strip (20) is guided over a coating roll (2),the strip surface lying opposite the coating roll (2) is covered with an endlessly configured mask strip (10),a coating is applied on the metal strip (20) in the covered region, andthe excess coating material is removed down to a desired layer thickness, before the mask strip (10) is removed from the surface of the metal strip (20).