Eddy Current Flaw Detection Noise Discrimination

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Solution Overview

Problem

Existing flaw-detection methods, such as eddy-current flaw detection, face challenges in distinguishing noise from defect signals due to similar waveform characteristics, leading to reduced precision and increased complexity with the need for additional sensors.

Innovation Solution

A flaw-detection apparatus with multiple sensors arranged in a row, where signal values at the same positional coordinate are compared to create filtering signals that amplify similar values, allowing for the differentiation of noise and defect signals without additional sensors, improving detection precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are arranged in a row to compare signal values at the same positional coordinate, then noise discrimination capability is improved, but device complexity increases

Engineering Contradiction:
Improvenoise discrimination capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The inspection system is segmented into multiple flaw-detection sensors arranged in a row along the scanning direction. Each sensor independently detects signals at slightly different positions, enabling comparison of signal values at the same positional coordinate to distinguish noise from actual defects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple detection signals from the arranged sensors are merged and processed together by the processing device. By combining the signals and comparing values at corresponding positional coordinates, the system achieves enhanced noise discrimination while maintaining a relatively simple overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If additional sensors are added to distinguish noise from defect signals, then detection precision is improved, but the number of components increases

Engineering Contradiction:
Improvedetection precisionVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

Instead of using a single sensor, the invention employs multiple sensors arranged in a row, providing partial redundancy in the detection process. This partial multiplication of components enables signal comparison and noise filtering without requiring a complete overhaul of the detection system.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If signal comparison method is used to filter noise, then false detection is reduced, but processing complexity increases

Engineering Contradiction:
Improvefalse detection rateVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection system creates multiple copies of the detection function through multiple sensors arranged in a row. Each sensor produces a signal that is essentially a copy of what the others would detect at their respective positions, allowing the processing device to compare these copies at the same positional coordinate to identify and filter noise.

Inventive Principle:
Principle #26Copying

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 effectively distinguishes noise from defect signals, enhancing detection precision with a simple setup, even in cases where noise and defects occur simultaneously.

Implementation Method 1

an eddy current is generated in an inspection object by generating flux changes with an exciting coil supplied with an excitation current; additionally, detection signals that represent the flux generated by this eddy current are obtained as output signals from a detection coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2518487B1Flaw detection device and flaw detection method
Publication Date: 2018.11.07 MITSUBISHI HEAVY IND LTD
  • EP2518487B1 patent drawingFigure 1~2
  • EP2518487B1 patent drawingFigure 3(a)~3(d)
  • EP2518487B1 patent drawingFigure 4(a)~4(d)

AI summary

Noise included in detection signals is distinguished with a simple configuration. Provided is a flaw-detection apparatus (1) including a flaw-detection sensor group (11) in which two flaw-detection sensors (11a and 11b) are arranged substantially in one row in a scanning direction with a distance therebetween and a processing device (15) that detects a defect in an inspection object on the basis of detection signals detected by the individual flaw-detection sensors (11a and 11b), wherein, with regard to the detection signals detected by the flaw-detection sensors (11a and 11b), when signal values detected at substantially a same positional coordinate in the scanning direction are not similar to each other, and, additionally, when signal values measured at a same time are similar to each other, the processing device (15) determines that the detection signals are not defect signals.