Demagnetization Method Using Magnetic Saturation

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Solution Overview

Problem

Existing methods for demagnetizing large-area ferromagnetic objects with limited thickness, accessible only from one side, such as heavy plates and large pipes, are inefficient and fail to reliably eliminate residual magnetism, which can cause corrosion and interfere with subsequent machining or welding processes.

Innovation Solution

A method using a bundle of current-carrying conductors arranged next to each other, with a width greater than the object's wall thickness, is placed on the object's surface, creating a magnetically saturated zone that interrupts and reduces residual flux circuits by moving relative to the surface, either continuously or in pulses, to achieve comprehensive demagnetization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal method is used for demagnetization, then demagnetization effect is achieved, but energy consumption increases and object damage occurs

Engineering Contradiction:
Improvedemagnetization effectVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the thermal demagnetization method with a magnetic field-based method. Instead of heating the ferromagnetic object to the Curie point to eliminate residual magnetism, the invention uses a conductor bundle generating a magnetic field that creates a magnetically saturated zone, interrupting residual flux circuits. This substitution eliminates high energy consumption and thermal damage while achieving effective demagnetization through magnetic field interaction alone.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional magnetic field methods are used, then demagnetization is attempted, but residual magnetism in thick-walled objects cannot be reliably eliminated

Engineering Contradiction:
Improvedemagnetization completenessVSAvoidmethod effectiveness
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a concentrated magnetically saturated zone directly at the object surface using the conductor bundle. The magnetic field is intensely localized where needed (at the surface and penetrating inward), interrupting flux circuits locally rather than requiring global demagnetization. This localized approach effectively addresses residual magnetism in thick-walled objects without requiring complex equipment, as the high field strength is confined to the critical region.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the magnetic field parameters by using a conductor bundle configuration that generates a magnetic field with specific characteristics: high field strength concentrated at the surface, with penetration depth sufficient for the wall thickness. The field strength and distribution parameters are optimized through the conductor bundle geometry and current, enabling reliable demagnetization of thick-walled objects where conventional methods fail.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If extensive surface coverage is used for demagnetization, then complete demagnetization is achieved, but process time and complexity increase

Engineering Contradiction:
Improvedemagnetization thoroughnessVSAvoidprocess time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent employs periodic action by moving the conductor bundle in discrete steps across the object surface rather than requiring continuous coverage. The bundle is positioned at intervals, creating magnetically saturated zones that interrupt flux circuits. The combination of stepping motion and periodic field application achieves thorough demagnetization efficiently, reducing process time while maintaining reliability through strategically placed treatment zones.

Inventive Principle:
Principle #19Periodic 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 effectively demagnetizes large-area ferromagnetic objects by creating a magnetically saturated zone that interrupts and reduces residual magnetism, ensuring thorough demagnetization without the need for extensive surface coverage or high energy consumption, thereby preventing corrosion and ensuring proper object handling.

Implementation Method 1

the magnetic field forming around a current-carrying conductor is used for demagnetization

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the bundle of conductors creating a magnetically saturated zone in the object

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP2755217B1Demagnetisation method
Publication Date: 2021.09.22 MAURER ALBERT
  • EP2755217B1 patent drawingFigure 1~2
  • EP2755217B1 patent drawingFigure 3~4
  • EP2755217B1 patent drawingFigure 5~6

AI summary

The method involves using a current-carrying conductor (33) that forms a magnetic field for demagnetization of a ferromagnetic plate (31). The conductor is placed on a surface (32) of the ferromagnetic plate at a distance less than or equal to the thickness of the conductor, where the conductor generates a magnetically saturated region (34) in the plate, where the width of the conductor is greater than a wall thickness (d) of the plate to be demagnetized. A part of the conductor facing away from the plate is covered by a channel made of ferromagnetic material.