Hall Element Inspection Probe for Quantitative Magnetic Pipe Thinning
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Solution Overview
Problem
Conventional magnetic flux leakage methods fail to detect defects like thinning over an entire circumference of a pipe or gradual thinning, as they rely on magnetic flux leakage, which only occurs at discontinuous pipe portions, and cannot quantitatively measure defect depth.
Innovation Solution
A defect measuring method and inspection probe using a Hall element to detect changes in magnetic flux density within a magnetic pipe, with a magnet and yoke forming a magnetic circuit, allowing for quantitative measurement of thinning depth by analyzing output voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic flux leakage method is used to detect defects, then discontinuous defects can be detected, but gradual thinning or entire circumference thinning cannot be detected
Solution Approach 1:
The patent changes the detection parameter from magnetic flux leakage (which only occurs at discontinuities) to magnetic flux density (which changes continuously with wall thickness). By measuring the density of magnetic flux rather than its leakage, the system can detect gradual thinning and entire circumference defects that were previously undetectable.
2Reliability
If magnetic flux leakage method is used, then defect presence can be determined, but quantitative measurement of defect depth is not possible
Solution Approach 1:
The patent replaces the magnetic flux leakage detection mechanism with a magnetic flux density measurement mechanism using a Hall element. This substitution enables quantitative measurement because the Hall element output voltage directly correlates with magnetic flux density, which in turn correlates with wall thickness, allowing precise depth measurement.
3Measurement precision
If Hall element is used to detect magnetic flux density, then quantitative defect measurement becomes possible, but device complexity increases
Solution Approach 1:
The patent merges the magnet, yoke, and Hall element into an integrated inspection probe assembly. The magnet and yoke form a magnetic circuit that concentrates magnetic flux through the pipe wall, while the Hall element is positioned to measure this flux density. This integration achieves quantitative measurement capability while keeping the device compact and manageable.
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 accurate and quantitative detection of defects in magnetic members, including thinning depth, even in cases where thinning occurs gradually or over the entire circumference, improving defect assessment in magnetic pipes.
Implementation Method 1
measuring an output from a magnetic sensor with use of an inspection probe including a magnet and the magnetic sensor which is provided on a magnetic circuit formed by the magnet and the magnetic member
Data Source
Figure 1~2(b)
Figure 3
Figure 4~4(b)
AI summary
A defect of a magnetic member is quantitatively measured. An inspection probe (100) includes a magnet (2) and a Hall element (3) which is provided on a magnetic circuit formed by the magnet (2) and a magnetic pipe (P) and which detects a density of a magnetic flux flowing through the magnetic circuit. With use of the inspection probe (100), an output from the Hall element (3) is measured. Based on the output from the Hall element (3), the presence/absence of the defect and a depth of the defect are calculated.