Dual-Coil Eddy Current Flaw Detection for Low Conductivity Materials
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Eddy current flaw detection in complex materials with low electric conductivity is hindered by low eddy current density and magnetic flux density, leading to reduced sensitivity, and existing solutions with high sensitivity, such as SQUID magnetic flux meters, are expensive and complex.
Innovation Solution
An eddy current flaw detection device comprising a first exciter/detector and a second exciter/detector or a backside body made of ferromagnetic material, disposed opposite each other to sandwich the tested object, inducing and detecting changes in the reactive magnetic field, allowing for high sensitivity detection without the need for complex cooling mechanisms or expensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a SQUID magnetic flux meter is used to improve flaw detection sensitivity, then detection sensitivity is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the detection system into two separate coils: a first excitation coil for generating the magnetic field and inducing eddy currents, and a second detection coil for detecting the reactive magnetic field. This segmentation allows each coil to be optimized for its specific function while avoiding the need for complex cooling mechanisms required by SQUID meters, thus reducing device complexity while maintaining detection sensitivity.
2Measurement precision
If a SQUID magnetic flux meter is used to improve flaw detection sensitivity, then detection sensitivity is improved, but device cost increases
Solution Approach 1:
The patent replaces the expensive SQUID magnetic flux meter with conventional excitation and detection coils that are much cheaper to manufacture. These coils do not require complex cooling mechanisms or expensive components, making the overall device cost-effective while still achieving the desired flaw detection sensitivity through proper coil configuration and positioning.
3Device complexity
If conventional single-coil eddy current detection is used, then device structure is simple, but detection sensitivity is low for complex materials
Solution Approach 1:
The patent transitions from a single-coil configuration to a dual-coil configuration where the first excitation coil and second detection coil are positioned on opposite sides of the tested object. This spatial arrangement in another dimension allows the magnetic field to penetrate through the object and enables detection of the reactive magnetic field generated by eddy currents, significantly improving detection sensitivity for complex materials while maintaining relatively simple device structure.
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 simplified, cost-effective, and highly sensitive eddy current flaw detection in complex materials by optimizing the placement and design of exciter and detector coils, enhancing magnetic flux density and detection accuracy.
Implementation Method 1
alternating current from an alternating current power source is supplied to an excitation coil to induce eddy current in the vicinity of a surface of a tested object
Implementation Method 2
A reactive magnetic field generated by the eddy current is detected by a detection coil
Implementation Method 3
a backside body made of ferromagnetic material disposed opposite side of the exciter/detector sandwiching the tested object therebetween
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An eddy current flaw detection device according to an embodiment includes: a first exciter/detector (20) that is supplied with alternating current and can induce eddy current in a tested object (11) by generating a magnetic field change in the tested object (11); a second exciter/detector (21) disposed opposite side of the first exciter/detector (20) sandwiching the tested object (11) therebetween. The second exciter/detector (20) can detect a change in a reactive magnetic field generated by the eddy current.