Hot dip coating device and method

Abstract

The invention relates to a hot dip coating device to provide a metal coating on a moving metal sheet, containing a liquid bath of metal coating material in use, wherein the metal coating material is to be provided on the moving metal sheet in use, comprising a container for the liquid bath, at least a guide or sink roll that is provided in the container below surface level of the liquid bath in use to guide the moving metal sheet through the bath, and a gas knife that is provided above the liquid bath in use, said gas knife having an outlet to project wiping gas on the metal coating provided on the metal sheet that in use passes along the gas knife, and wherein at least one supporting roll is provided which together with the guide or sink roll in use influence a shape of the metal sheet inits width direction at least at the location of the gas knife. According to the invention, in use the at least one supporting roll is placed above surface level of the liquid bath on a position enabling it to operate on the metal sheet before the metal sheet enters the liquid bath. The invention also relates to a method for use of the hot dip coating device.

Description

technical field [0001] The present invention relates to a hot dip coating apparatus for providing a metallic coating on a moving metal sheet, comprising in use a liquid bath of metallic coating material, wherein the metallic coating material is, in use, provided on a moving metallic sheet, comprising A container for a liquid bath, at least a guide or sinking roller arranged in the container below the surface level of the liquid bath in use to guide the moving metal sheet through the liquid bath and an air knife arranged in use above the liquid bath, said air knife having an outlet to project wiping gas onto a metal coating provided on a metal sheet which in use passes along the gas knife, and wherein at least one support roller is provided, said at least one support roller and said guide or The sinker roll influences the shape of the metal sheet in its width direction during use at least at the location of the air knife. The invention also relates to a method of coating a mov...

AI Technical Summary

Problems solved by technology

This not only adversely affects the operating costs of the hot dip coating plant, but also adversely affects the productivity of the plant due to the unavoidable loss of production time due to the required maintenance

[0009] Another problem with one or more support rollers known in liquid metal baths is that wet frictional contact of the rollers with the moving metal sheet in the liquid bath causes the rollers to rotate, which leads to damage due to slippage between the roller and the moving metal sheet possible sheet metal damage

Also, from design considerations, the manner in which the one or more support rollers are driven creates a limitation on the processing speed of the device, since the speed of the moving metal sheet is limited to the sliding edge points

[0010] Another problem with submerged one or more support rolls is that the flow of liquid metal in the liquid metal bath is affected by the rotating rolls, and the flow pattern within the liquid metal bath can cause impurities in the bath to deposit on the surface of the moving metal sheet superior

[0011] Finally, there are limitations in the design of known coating devices related to the required structural support for one or more backup rolls, which are usually arranged above the bath level, where the space due to the air knife should Restricted near the surface level of the metal bath

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