Segmented Through-Coil Arrangement for Eddy Current Testing
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Solution Overview
Problem
Existing continuous coil arrangements for testing long products using eddy currents face challenges in providing comprehensive surface coverage and accurate defect localization, particularly in the circumferential direction, due to overlapping coil segments leading to measurement inaccuracies and reduced signal-to-noise ratios.
Innovation Solution
A through-type coil arrangement with segment coil arrangements distributed over multiple shells at different radial distances, allowing non-overlapping configurations that enable precise localization of defects both axially and circumferentially, using differential and absolute coil arrangements for enhanced sensitivity and distance sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If segment coil arrangements are overlapped in the circumferential direction to achieve complete surface coverage, then the coverage area is improved, but measurement precision deteriorates due to signal interference and reduced signal-to-noise ratio
Solution Approach 1:
The receiver coil arrangement is divided into multiple segment coil arrangements distributed over different shells. Each segment coil arrangement has a specific detection area covering only part of the circumference, avoiding overlap while collectively providing complete coverage. This segmentation allows precise defect localization to specific circumferential sections without signal interference from overlapping coils.
Solution Approach 2:
Segment coil arrangements are distributed over multiple shells at different radial distances from the reference axis, adding a radial dimension to the arrangement. This multi-shell configuration allows non-overlapping circumferential coverage while maintaining complete surface monitoring, as each shell contributes to coverage at its specific radial position.
2Device complexity
If a single shell configuration is used to simplify the device structure, then device complexity is reduced, but defect localization accuracy deteriorates due to inability to distinguish axial and circumferential positions
Solution Approach 1:
The invention transitions from a single-shell to a multi-shell configuration, adding the radial dimension to the coil arrangement. This allows segment coil arrangements on different shells to be associated with different axial positions, enabling precise three-dimensional defect localization (axial position, circumferential position, and radial depth information) while maintaining manageable device complexity through systematic distribution.
Solution Approach 2:
Each segment coil arrangement is assigned a specific detection area covering a particular circumferential segment and axial position. The local quality principle is applied by optimizing each segment's characteristics for its specific location, allowing precise defect localization to specific sections of the long product surface without requiring complex overall restructuring.
3Measurement precision
If segment coil arrangements are distributed over multiple shells, then defect localization accuracy is improved, but device complexity increases due to additional coil arrangements and connection devices
Solution Approach 1:
The receiver coil arrangement is segmented into multiple distributed segment coil arrangements, each with its own connection device. This segmentation enables precise defect localization by identifying which specific segment detects the defect, providing both circumferential and axial position information while keeping each individual segment relatively simple in design.
Solution Approach 2:
Each segment coil arrangement serves multiple functions: detecting defects, providing circumferential position information, and providing axial position information (through its shell location). This multi-functionality reduces the need for additional separate systems, balancing the increased number of components with the versatility of each individual segment.
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 ensures robust and reliable defect detection with improved signal comparability and localization accuracy, enabling continuous testing with reduced measurement inaccuracies and enhanced defect characterization.
Implementation Method 1
an alternating current (eddy current) of suitable orientation, size and frequency is induced in the material to be tested by an alternating current-operated excitation coil
Implementation Method 2
the resulting irregularities in the eddy current are recorded and evaluated with the help of sensors, e.g. a coil arrangement
Data Source
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AI summary
A through-coil arrangement (100) for use in a testing device for testing elongated products in a feed-through method by means of eddy currents has a field coil arrangement with a field coil (122) enclosing a passage opening (112) for guiding an elongated product (190) along a feed-through direction (192), and a receiver coil arrangement arranged around the passage opening. The receiver coil arrangement has two or more segment coil arrangements (142-1 to 142-8) distributed around the periphery of the passage opening (112), each segment coil arrangement having a detection range that covers only a peripheral section of the periphery of the surface of the elongated product. The segment coil arrangements (142-1 to 142-8) are distributed on at least two shells (S1, S2) surrounding the passage opening at different distances (A1, A2) from a reference axis (114) of the through-coil arrangement. First segment coil arrangements (142-1 to 142-4) are arranged without mutual overlapping on a first shell (S1) and second segment coil arrangements (142-5 to 142-8) are arranged without mutual overlapping on a second shell (S2). First and second segment coil arrangements are arranged peripherally offset from one another in the peripheral direction in such a way that the second segment coil arrangements detect peripheral sections that are not covered by the first segment coil arrangements.