Hot-Dip Coating Roll Layout for Sheet Shape and Wear Control
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Solution Overview
Problem
The existing hot dip coating devices face issues with roll wear, maintenance costs, production downtime, metal sheet damage due to slippage, and limitations in processing speed due to submerged supporting rolls, as well as design constraints and impurity settlement on the metal sheet.
Innovation Solution
Positioning the supporting rolls above the liquid bath level, providing them with a motor drive, and using a movable gas knife and sink roll to maintain sheet shape while reducing frictional contact and enabling easier maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If supporting rolls are positioned below surface level of the liquid bath to guide the metal sheet, then the metal sheet shape can be controlled at the gas knife location, but the rolls experience wear requiring regular maintenance and cause production downtime
Solution Approach 1:
The supporting rolls are extracted from the liquid bath environment and positioned above the surface level. This removes them from the harmful liquid metal environment that causes wear, while they still perform their function of controlling the metal sheet shape through the combined action of multiple rolls (sink roll, supporting rolls, and correcting roll) that influence the sheet's crossbow and alignment at the gas knife location.
2Manufacturing precision
If supporting rolls are submerged in the liquid metal bath, then they can align the metal sheet with the gas knife, but the wet frictional contact causes the rolls to rotate and limits processing speed
Solution Approach 1:
The supporting rolls are positioned above the liquid bath surface, eliminating wet frictional contact. This prevents the rolls from rotating due to friction and removes the speed limitation, while alignment is still achieved through the geometric arrangement and combined action of multiple rolls including the sink roll, supporting rolls, and correcting roll.
3Manufacturing precision
If multiple supporting rolls are provided in the liquid metal bath, then the metal sheet shape and alignment can be controlled, but the device complexity and maintenance requirements increase
Solution Approach 1:
The supporting rolls are extracted from the liquid bath, simplifying their maintenance requirements. The system uses a coordinated arrangement of multiple rolls (sink roll, supporting rolls, and correcting roll) positioned above or at the bath surface to achieve shape and alignment control, reducing the complexity of maintaining rolls in the harsh liquid metal environment.
4Manufacturing precision
If rolls are positioned in the liquid metal bath to control metal sheet shape, then coating uniformity can be improved, but roll wear increases maintenance costs
Solution Approach 1:
The supporting rolls are extracted from the liquid metal bath and positioned above the surface. This eliminates the wear caused by contact with liquid metal, significantly reducing maintenance costs. The coating uniformity is still achieved through the combined action of multiple rolls (sink roll, supporting rolls, and correcting roll) that control the metal sheet's crossbow and shape at the gas knife location.
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 configuration reduces roll wear, minimizes metal sheet damage, enhances production capacity, and improves coating uniformity by controlling crossbow and thickness variations.
Implementation Method 1
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
Implementation Method 2
at least one supporting roll is provided which together with the guide or sink roll in use influence a shape of the metal sheet in its width direction at least at the location of the gas knife
Data Source
AI summary
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. The metal coating material on the moving metal sheet in use, including a container for the liquid bath, a guide or sink roll in the container below liquid bath surface level in use to guide the moving metal sheet through the bath, and a gas knife, above the liquid bath in use, having an outlet to project wiping gas on the metal coating on the metal sheet. At least one supporting roll with the guide or sink roll in use influence metal sheet shape in its width direction at the gas knife location. The one supporting roll is above liquid bath surface level to operate on the metal sheet before the metal sheet enters the bath.