Hot Dip Coating Movable Wiping System for Strip Width Adaptation
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Solution Overview
Problem
Existing hot dip coating installations for metal strips are not flexible enough to achieve satisfactory coatings for various production types, as coating quality varies with operating parameters and metal strip format, such as width and thickness.
Innovation Solution
The installation features a movable wiping system with vertically adjustable nozzles and a confinement box with independent upper and lower parts, allowing for adjustable gas flow and atmosphere control to maintain consistent coating quality across different production conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed confinement box is used in the hot dip coating installation, then the structure is simple and stable, but the coating quality cannot be adjusted for different production types and metal strip formats
Solution Approach 1:
The confinement box is divided into a fixed upper part and a movable lower part that can be displaced vertically between a bottom position (partially immersed in the melt bath) and a top position (creating free space). This dynamic structure allows the same device to adapt to different production requirements while maintaining structural simplicity.
Solution Approach 2:
The confinement box is segmented into an upper confinement part and a lower confinement part that can move independently. This segmentation enables the lower part to be adjusted for different coating conditions while the upper part remains fixed, resolving the contradiction between adaptability and structural complexity.
2Manufacturing precision
If the nozzles are fixed relative to the pot, then the wiping system is simple, but the coating thickness and quality cannot be controlled for varying line speeds and metal strip formats
Solution Approach 1:
The nozzles are made vertically movable relative to the pot, allowing adjustment of their position to optimize the turbulent slot jet wiping action for different line speeds and metal strip formats. This dynamic positioning enables precise coating thickness control without requiring an overly complex positioning system.
3Object-affected harmful factors
If the lower confinement part remains above the melt bath surface, then the structure is simple, but gas tightness and oxidation prevention are insufficient
Solution Approach 1:
The lower confinement part can be displaced to a bottom position where it is partially immersed in the melt bath, creating a gas-tight seal that prevents oxidation. When oxidation prevention is not needed, it can be moved to a top position creating free space. This dynamic positioning allows the system to switch between oxidation protection mode and simple operation mode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures consistent and high-quality coatings for metal strips of varying widths and thicknesses, reducing defects like edge over-coating and adapting to changes in line speed and bath-to-nozzle distance, while maintaining gas tightness and preventing oxidation.
Implementation Method 1
a turbulent slot jet is used to wipe the excess metal and control the thickness of the coating
Implementation Method 2
a box with a lower confinement part for confining an atmosphere around the metal strip upstream of the nozzles, an upper confinement part for confining the atmosphere around the metal strip downstream of the nozzles
Data Source
AI summary
An installation for hot dip coating a metal strip is provided. The installation includes a device for moving the metal strip along a path, a pot for containing a melt bath and a wiping system including at least two nozzles placed on either side of the path downstream the pot. The wiping system has a box with a lower confinement part confining an atmosphere around the metal strip upstream of said nozzles and an upper confinement part confining the atmosphere around the metal strip downstream of the nozzles, first moving means for vertically moving the lower confinement part with respect to the pot and second moving means for vertically moving the upper confinement part with respect to both the pot and the lower confinement part. The nozzles are vertically movable relative to the pot.