Electromagnetic Strip Stabilization for Hot-Dip Coating

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Solution Overview

Problem

In hot-dip coating plants, existing strip stabilization systems downstream of the wiping nozzles are ineffective in maintaining coating quality and uniformity due to increased distance from the nozzles, leading to reduced damping of strip movements and instability in the coating process.

Innovation Solution

The method involves setting the distance of strip stabilization from the wiping nozzles to a value less than or equal to a threshold determined by the strip width, taking into account a Phi factor calculated from strip thickness and tension, using electromagnetic coils to apply non-contact forces and measuring the strip position for optimal stabilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strip stabilization coils are positioned downstream of the wiping nozzles, then the strip position can be controlled, but the stabilization effect is significantly reduced due to increased distance from the nozzles

Engineering Contradiction:
Improvestrip position controlVSAvoidcoating uniformity
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The strip stabilization coils are positioned upstream of the wiping nozzles rather than downstream, allowing the stabilization effect to act on the strip before it enters the critical coating zone. This preliminary action ensures that strip movements are damped while the strip is still in the stabilization zone, maintaining coating uniformity and quality.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the distance between strip stabilization and wiping nozzles is increased, then structural conditions are easier to meet, but the damping effect on strip movements is significantly reduced

Engineering Contradiction:
Improvestructural feasibilityVSAvoidstrip movement damping
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

By positioning the stabilization coils upstream, the system performs the stabilization action in advance, within the available space before the wiping nozzles. This allows sufficient distance for the electromagnetic field to act on the strip and dampen movements before the strip reaches the coating zone, maintaining both structural feasibility and stabilization effectiveness.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If strip stabilization is positioned closer to the air knife, then the stabilization effect on coating quality is improved, but space constraints and structural conditions become more difficult to meet

Engineering Contradiction:
Improvecoating accuracyVSAvoidstructural constraints
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The upstream positioning of stabilization coils creates a dedicated stabilization zone before the wiping nozzles, allowing the electromagnetic field to act on the strip over an optimized distance. This preliminary stabilization zone is designed to provide sufficient damping effect while respecting the structural constraints of the coating line layout.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If downstream strip stabilization is used, then strip position can be adjusted, but the effect is reduced due to the distance from the nozzles causing increased instability

Engineering Contradiction:
Improvestrip position adjustmentVSAvoidstrip stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

By positioning the stabilization coils upstream of the wiping nozzles, the system performs strip position control and stabilization in advance, within the optimal electromagnetic field influence zone. This allows effective damping of strip movements and maintenance of strip stability while still providing the necessary position adjustment capability.

Inventive Principle:
Principle #10Preliminary action

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 approach significantly improves strip stabilization, maintaining coating accuracy and uniformity by ensuring the stabilization effect is within a defined range, preventing increased instability and maintaining optimal strip positioning, even when the strip is inclined or twisted.

Implementation Method 1

Electromagnetic strip stabilization is based on the principle of induction in order to generate attractive forces perpendicular to the ferromagnetic steel strip using defined magnetic fields

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

generate attractive forces perpendicular to the ferromagnetic steel strip using defined magnetic fields

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

attractive forces perpendicular to the ferromagnetic steel strip

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP2188403B1Process and hot-dip coating system for stabilizing a strip guided between stripping dies of the hot-dip coating system and provided with a coating
Publication Date: 2012.07.25 SMS GROUP GMBH
  • EP2188403B1 patent drawingFigure 1~3
  • EP2188403B1 patent drawingFigure 4~5
  • EP2188403B1 patent drawingFigure 6

AI summary

The invention relates to a process for stabilizing a strip guided between stripping dies of a hot-dip coating system and provided with a coating, and also to a corresponding hot-dip coating system. In this context, stabilizing forces are exerted on the strip on the basis of the detected strip position by means of spools which are arranged downstream of the stripping dies in the strip running direction and act electromagnetically and in a contactless fashion on the steel strip running through. In order to improve the stabilization of the strip in the region of the stripping die, the invention proposes that the distance between the line of action of the strip-stabilizing device and the stripping dies be adjusted to a value ≤ a distance threshold value which is determined as a function of the strip width taking into account a factor Phi, wherein the factor Phi is calculated as a function of the strip thickness and the strip tension.