Eddy Current Flaw Detection Device Using Segmented Magnet
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Solution Overview
Problem
Eddy current flaw detection devices face challenges in applying a strong magnetic field without increasing size and weight, making it difficult to detect small flaws on conductive materials with heterogeneous magnetic permeabilities.
Innovation Solution
The device employs a magnetic-field forming magnet composed of multiple magnet pieces, including a base and tip magnet piece, strategically arranged to concentrate magnetic flux and achieve a high surface magnetic-flux density, allowing for effective magnetic saturation without the need for large, heavy magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large electromagnet is used to generate a strong magnetic field for magnetic saturation, then the magnetic field strength is sufficient, but the device size and weight increase significantly
Solution Approach 1:
The magnetic field forming magnet is divided into multiple magnet pieces (first magnet piece, second magnet piece, and third magnet piece) with different sizes and positions. This segmentation allows the system to generate a strong magnetic field through coordinated arrangement of smaller magnets rather than using a single large electromagnet, thereby reducing overall device weight while maintaining sufficient magnetic field strength for magnetic saturation.
Solution Approach 2:
Different magnet pieces are positioned at different locations (first magnet piece near the detection part, second magnet piece further away, third magnet piece on the opposite side) with varying sizes. This local quality differentiation creates a concentrated strong magnetic field in the inspection region while using smaller magnets overall, achieving magnetic saturation without requiring a large heavy electromagnet throughout the entire device.
2Temperature
If a large electromagnet is used to generate a strong magnetic field for magnetic saturation, then the magnetic field strength is sufficient, but the device dimensions increase
Solution Approach 1:
The magnetic field forming magnet is divided into multiple magnet pieces (first magnet piece, second magnet piece, and third magnet piece) with different sizes and positions. This segmentation allows the system to generate a strong magnetic field through coordinated arrangement of smaller magnets rather than using a single large electromagnet, thereby reducing overall device weight while maintaining sufficient magnetic field strength for magnetic saturation.
Solution Approach 2:
The patent arranges magnet pieces in three-dimensional space with the first magnet piece near the detection part, the second magnet piece further away in a different position, and the third magnet piece on the opposite side. This spatial arrangement in multiple dimensions allows the system to concentrate magnetic flux in the inspection region using smaller individual magnets, avoiding the need for a single large electromagnet that would increase device length.
3Weight of moving object
If a small permanent magnet is used, then the device size and weight are reduced, but the magnetic field strength is insufficient for magnetic saturation
Solution Approach 1:
The patent combines multiple permanent magnet pieces (first, second, and third magnet pieces) to form a magnetic field forming magnet system. By merging the magnetic fields of these smaller permanent magnets through strategic positioning and arrangement, the system achieves a cumulative strong magnetic field sufficient for magnetic saturation, overcoming the limitation of individual small permanent magnets while maintaining reduced device weight.
Solution Approach 2:
Different magnet pieces are positioned at different locations (first magnet piece near the detection part, second magnet piece further away, third magnet piece on the opposite side) with varying sizes. This local quality differentiation creates a concentrated strong magnetic field in the inspection region while using smaller magnets overall, achieving magnetic saturation without requiring a large heavy electromagnet throughout the entire device.
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 enables the detection of small flaws with reduced noise interference, allowing for efficient inspection of materials with varying magnetic permeabilities while maintaining a compact and lightweight device.
Implementation Method 1
The test object is brought into magnetic saturation, that is, a difference in magnetic permeabilities between a ferromagnetic material and a non-ferromagnetic material is substantially eliminated
Implementation Method 2
a strong and uniform magnetic field is applied to a test object so as to cancel out an uneven magnetic field generated in an inspection region
Implementation Method 3
The device generates eddy current on a test object and detects the intensity of the eddy current and the change of the shape of eddy current flow
Data Source
AI summary
The present invention provides an eddy current flaw detection device capable of applying a sufficiently strong magnetic field to a test object without using a significantly large magnet. A magnetic-field forming magnet 60 includes a base magnet piece 60a and a tip magnet piece 60b. The tip magnet piece 60b has a tip pole face 62 from which a magnetic pole is directed toward a test object 30. The tip pole face 62 has a smaller area than a base face 64 of the base magnet piece 60a, the base face 64 being located on the opposite side of the magnetic-field forming magnet 60 from the tip pole face 62.