Bushing Melt Detection via Grounded Mesh Circuit

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Solution Overview

Problem

Existing detection methods for melt adjacent to the bushing in an electric induction channel furnace require the melt to be at above ground potential and rely on electromagnetically induced voltage, which is not feasible in all scenarios, and do not effectively detect melt penetration without grounding the melt.

Innovation Solution

A method involving a spaced apart and interconnected electrical conductor mesh around the bushing, connected to a grounded voltage source, which detects increased ground circuit current when conductive melt at ground potential penetrates the refractory and establishes electrical continuity with the mesh, allowing for melt detection without altering the melt's ground potential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the melt is kept at ground potential without electromagnetically induced voltage, then the detection system becomes simpler and safer, but the ability to detect melt penetration is lost

Engineering Contradiction:

Improvedetection system complexityVSAvoidmelt penetration detection capability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary conductive element (the mesh or screen) positioned between the melt and the detection circuit. This intermediary allows the detection of melt penetration through resistive measurement without requiring the melt itself to be at above-ground potential or requiring complex electromagnetic induction systems. The intermediary serves as a safe interface that enables detection while maintaining the melt at ground potential.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex electromagnetic induction-based detection systems with a simpler electrical resistance measurement system. Instead of using electromagnetic fields to detect melt position, the invention uses direct electrical resistance measurements through the refractory and conductive elements, substituting a complex electromagnetic system with a simpler electrical measurement approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a wire conductor connects the bushing to ground for detection, then melt penetration can be detected, but the system requires above ground potential which limits applicability

Engineering Contradiction:

Improvemelt penetration detection capabilityVSAvoidapplicability to different furnace configurations

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal detection system that can be applied to various furnace configurations by using a standardized mesh or screen structure that can be positioned around different bushing types. The system works with both water-cooled and air-cooled bushings, and can be implemented in different furnace designs, making it highly adaptable and versatile across various industrial applications.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If two fire walls are used to detect melt penetration, then detection capability is improved, but the device complexity and refractory requirements increase

Engineering Contradiction:

Improvemelt penetration detection capabilityVSAvoidrefractory structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from the complex dual-firewall refractory structure and implements it through a simpler mesh or screen element positioned within the refractory. This separates the detection functionality from the structural refractory requirements, allowing detection without needing heavy, complex firewall constructions. The mesh serves as the primary detection element rather than relying on measuring resistance between thick firewall structures.

Inventive Principle:

Principle #2Taking out (Extraction)

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

Enables reliable detection of melt adjacent to the bushing by monitoring ground circuit current, ensuring safe operation by alerting operators and disconnecting power when a breach occurs, while maintaining the melt at ground potential and avoiding induced voltages.

Implementation Method 1

An increased level of ground circuit current is detected when an electrically conductive melt at electrical ground potential in the channel of the furnace penetrates the refractory separating the channel from the arrangement of spaced apart and interconnected electrical conductors and establishes electrical continuity between at least some of the spaced apart and interconnected electrical conductors

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentUS9693399B1Detection of melt adjacent to the exterior of the bushing in an induction channel furnace

Publication Date: 2017.06.27 INDUCTOTHERM CORP

AI summary

A method is provided for the detection of melt adjacent to the exterior of a bushing in an induction channel furnace. An electrically conductive mesh is disposed around the exterior surface of the bushing facing a refractory that separates the bushing from a channel in which molten metal (melt) flows. The mesh is connected to a grounded voltage source so that when an electrically conductive melt at ground potential in the channel breaches the refractory and penetrates the electrically conductive mesh an electrical circuit is completed through the melt and the grounded voltage source.