Dual-Purpose Coil Pulsed Eddy Current Testing

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Solution Overview

Problem

Pulsed Eddy Current (PEC) systems face limitations due to the need for separate transmitting and receiving coils, which increase the number of components, weight, and power losses, especially in compact and portable applications, and can suffer from crosstalk and reduced flexibility.

Innovation Solution

A dual-purpose coil configuration that serves both as a transmitter and receiver, driven by a transmitter circuit with distinct phases for magnetic field production and measurement, utilizing a shut-off current circuit and receiver circuit to induce and measure eddy currents, respectively, while minimizing power consumption and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate transmitting and receiving coils are used, then the magnetic field production and measurement functions are optimized, but the number of components, weight, and device complexity increase

Engineering Contradiction:
Improvemagnetic field production and measurement optimizationVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the transmitting coil and receiving coil into a single dual-purpose coil that performs both functions. The coil is designed with specific electrical characteristics that allow it to effectively generate magnetic fields for eddy current induction while also serving as a sensor to measure the resulting magnetic field variations, thereby reducing component count and system complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dual-purpose coil is designed to fulfill multiple functions: it acts as both the transmitting element that generates the magnetic field and the receiving element that measures the magnetic field variations caused by eddy currents. This multi-functional design eliminates the need for separate coils and reduces overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If separate transmitting and receiving coils are used, then the measurement function is optimized, but the weight of the system increases

Engineering Contradiction:
Improvemagnetic field measurementVSAvoidsystem weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

By merging the transmitting and receiving coils into a single dual-purpose coil, the patent directly reduces the weight of the probe assembly. The elimination of redundant coil structures and associated mounting hardware results in a lighter overall system while maintaining measurement capability

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If low inductance transmitting coil is used, then the magnetic field cutting-off is improved, but the power consumption increases

Engineering Contradiction:
Improvemagnetic field cutting-off speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the electrical parameters of the dual-purpose coil, specifically balancing the inductance value and turn density to achieve both rapid magnetic field cutting-off and reduced power consumption. The coil is designed with specific inductance characteristics that allow fast transient response while minimizing the current required to generate the necessary magnetic field strength

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If extension cable is used for transmitting coil, then the flexibility is improved, but the power losses increase

Engineering Contradiction:
Improvecable flexibilityVSAvoidJoule effect power losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

By combining the transmitting and receiving functions into a single coil, the patent reduces the total length of extension cables required, thereby reducing Joule losses while maintaining the flexibility needed for various inspection configurations

Inventive Principle:
Principle #5Merging (Combining)

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 configuration reduces the number of coils needed, improves measurement precision, and enhances the flexibility and weight efficiency of the PEC system, allowing for more effective and portable non-destructive testing.

Implementation Method 1

The working principle is to induce transient eddy currents inside the object being inspected by means of a sharp electromagnetic transition

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

measure its decay to infer material thickness or property changes

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

cutting-off a current in the dual-purpose coil to produce a magnetic field variation which induces eddy currents in the object

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

induce transient eddy currents inside the object being inspected

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP3182113B1Pulsed eddy current testing with dual-purpose coils
Publication Date: 2018.11.07 EDDYFI NDT INC
  • EP3182113B1 patent drawingFigure 1A~1C
  • EP3182113B1 patent drawingFigure 2A~2C
  • EP3182113B1 patent drawingFigure 3A~4B

AI summary

A Pulsed Eddy Current device for inspecting an object made of an electrically conductive material comprising: at least one dual-purpose coil serving a dual purpose of producing a supplied magnetic field in the object and measuring a produced magnetic field emitted by the object, a transmitter circuit driving the dual-purpose coil(s) with an electrical signal, a shut-off current circuit for the transmitter circuit for cutting-off a current in the dual-purpose coil(s) during a cut-off phase of the electrical signal, the shut-off current circuit applying a voltage inversion on the dual-purpose coil(s) and a receiver circuit for reading the produced magnetic field from the dual-purpose coil(s). A method for inspecting an object comprising supplying a voltage on at least one dual-purpose coil, cutting-off a current in the dual-purpose coil(s) by applying a voltage inversion on the dual-purpose coil(s) and receiving, at the dual-purpose coil(s), a produced magnetic field.