Magnetic Field Sensor Array for Buried Pipeline Coating Defect Detection
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Solution Overview
Problem
Buried pipelines installed using horizontal directional drilling pose challenges for corrosion detection due to limited access and increased coating damage, which can lead to premature corrosion, and existing methods are inadequate for detecting coating defects in such scenarios.
Innovation Solution
A magnetic field sensor array is placed inside the pipeline to detect changes in the magnetic field caused by coating defects, utilizing Hall effect, GMR, or flux gate magnetometer sensors, which travel along the pipeline to identify variations in the magnetic field indicative of coating damage, and a detection unit processes the data to determine the extent and location of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If horizontal directional drilling is used to install pipelines, then pipeline installation flexibility is improved, but coating damage increases and corrosion detection becomes more difficult
Solution Approach 1:
The patent applies preliminary action by performing corrosion detection immediately after horizontal directional drilling installation, before the pipeline enters service. The inspection tool is deployed through the pipeline to detect coating defects and corrosion conditions while the pipeline is still accessible and can be isolated, allowing for preventive maintenance before operational stresses and environmental exposure accelerate degradation.
2Measurement precision
If traditional surface-based corrosion detection methods are used, then detection capability is improved for trenched pipelines, but applicability to horizontally drilled pipelines deteriorates due to limited surface access
Solution Approach 1:
The patent applies inversion by reversing the traditional detection approach. Instead of accessing the pipeline from the external surface (as with conventional electrical noise corrosion detection), the inspection tool accesses the pipeline from the internal flow path. The sensor array is deployed inside the pipeline to measure electrical potentials and detect coating defects from the interior, enabling detection in horizontally drilled pipelines where surface access is limited.
Solution Approach 2:
The patent uses the pipeline's internal flow as an intermediary medium to deploy the inspection tool. The flow-driven carrier propels the sensor array through the pipeline without requiring external access points or excavation. This intermediary approach allows the detection system to reach buried horizontally drilled pipelines that are inaccessible to surface-based methods.
3Ease of operation
If in-situ detection methods are implemented, then pipeline accessibility requirements are reduced, but detection system complexity increases
Solution Approach 1:
The patent applies universality by designing an inspection tool that performs multiple functions within a single integrated system. The sensor array includes both electrical noise corrosion detection sensors and coating defect detection sensors, allowing the same device to assess multiple aspects of pipeline condition. The flow-driven carrier provides both propulsion and positioning functions, reducing the need for separate deployment and control systems.
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 method allows for in-situ detection of coating defects in buried pipelines, enabling timely assessment of coating condition and determining the need for repair or replacement, thereby ensuring effective cathodic protection and preventing premature corrosion.
Implementation Method 1
utilizing Hall effect, GMR, or flux gate magnetometer sensors
Implementation Method 2
utilizing Hall effect, GMR, or flux gate magnetometer sensors
Implementation Method 3
utilizing Hall effect, GMR, or flux gate magnetometer sensors
Implementation Method 4
Active cathodic protection uses impressed currents; a current is applied to the conductive pipe wall to force it to act as a cathode
Data Source
AI summary
A method for in-situ detection of coating defects on a buried pipeline. The pipeline is under cathodic protection or otherwise carries a current applied to its pipe walls. A magnetic field sensor array is placed within the pipeline and moved along its length. As the sensor array travels, it detects the magnetic fields within the pipeline. The sensor output is compared with “expected” data, which represents interior magnetic fields of the pipeline without coating defects. Because electrical current leaks through a coating defect, the current is altered on the pipe wall at the defect. This in turn alters the interior magnetic fields, and a change in the interior magnetic fields indicates a coating defect.