Vortex Reduction in Metal Tapping via Electromagnetic Stirring

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Solution Overview

Problem

Existing methods for reducing vortex formation during metal tapping in metallurgical processes are ineffective in preventing vortex formation and do not address the issue of slag carry-over, which degrades metal quality.

Innovation Solution

A method involving a time-varying electromagnetic field generated by an electromagnetic stirrer creates a forced convection flow that constantly moves vortices away from the tapping hole region, preventing their accumulation and subsequent formation, thereby reducing the likelihood of slag carry-over.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an electromagnetic field is used to generate counter-rotational motion in the melt, then vortex formation is counteracted, but it is difficult to determine the rotational speed of the vortex and the method does not prevent vortex formation

Engineering Contradiction:

Improvevortex formationVSAvoidrotational speed of vortex

Core Design Contradiction:

Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

Instead of generating counter-rotational motion to oppose existing vortices, the invention applies electromagnetic force to generate unidirectional forced convection flow that moves molten metal away from the tapping hole region, thereby preventing vortex formation through a fundamentally different flow control mechanism

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The electromagnetic stirrer is activated before tapping to establish forced convection flow patterns that prevent vortex formation from occurring in the first place, rather than attempting to counteract vortices after they have formed

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If electromagnetic stirrer generates forced convection flow to move vortices away from tapping hole, then vortex formation is prevented, but energy consumption increases

Engineering Contradiction:

Improvevortex formationVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The electromagnetic stirrer generates sufficient forced convection flow to achieve the minimum necessary effect of preventing vortex formation, rather than maintaining excessively high flow rates, thereby optimizing energy consumption while achieving the desired protective effect

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The electromagnetic stirrer operates continuously during the tapping process to maintain forced convection flow that consistently prevents vortex formation, ensuring continuous protection without interruption that would require energy-intensive re-establishment of flow patterns

Inventive Principle:

Principle #20Continuity of useful action

3Manufacturing precision

If forced convection flow is applied to prevent vortex formation, then metal quality is improved, but the flow pattern must be precisely controlled to avoid disturbing metal mix

Engineering Contradiction:

Improvemetal qualityVSAvoidflow control system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The electromagnetic stirrer is positioned and configured to generate forced convection flow specifically in the region above the tapping hole where vortex formation occurs, while maintaining minimal disturbance to the bulk metal mix in other regions of the vessel, achieving localized protection without global disruption

Inventive Principle:

Principle #3Local quality

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 effectively prevents vortex formation above the tapping hole, improving metal quality by minimizing slag transfer to the next metallurgical vessel and optimizing metal flow without disturbing the metal mix.

Implementation Method 1

providing a flow of forced convection type of the molten metal in the metallurgical vessel while tapping by means of a time-varying electromagnetic field applied to the metallurgical vessel and provided by an electromagnetic stirrer

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the flow of the molten metal being such that it constantly moves vortices in the molten metal away from a tapping hole region

Methodology Applied

Scientific EffectForced convection: Forced Convection

Data Source

PatentEP2751510B1Method and arrangement for vortex reduction in a metal making process

Publication Date: 2017.05.31 ABB RES LTD

Figure 1
Figure 2a~3

AI summary

It is presented a method for reducing vortex formation in molten metal (21) when bottom tapping the molten metal from a metallurgical vessel (3) in a metal making process. The method comprises the steps of tapping the molten metal (21) via a tapping hole (17) in the metallurgical vessel (3), and providing a flow (F) of the molten metal (21) in the metallurgical vessel (3) while tapping by means of a time- varying electromagnetic field applied to the metallurgical vessel (3), the flow of the molten metal (21) being such that it constantly moves vortices (V1, V2, V3, V4, V5) in the molten metal (21) away from a tapping hole region during the tapping to thereby prevent accumulation of the vortices (V1, V2, V3, V4, V5) for vortex formation over the tapping hole (17). It is also presented an arrangement (1) for carrying out the method.