Terahertz Pipe Defect Detection via Non-Collinear Geometry
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Solution Overview
Problem
Butt weld fusion of polyethylene gas pipes can be compromised by contaminants, non-ideal pressure, and cold fusion issues, making it difficult to detect defects, which can lead to hazardous gas leaks and costly repairs.
Innovation Solution
The use of Terahertz (THz) spectroscopy and imaging for non-destructive evaluation (NDE) to detect defects in polyethylene pipe joints, including contaminants, pressure issues, and cold fusion, by transmitting and receiving THz waveform pulses and analyzing the differences in amplitude and polarization to ensure pipe joint integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional THz inspection methods (collinear transmission or reflection measurements) are used, then the inspection process is simple, but defect detection within the pipe weld is not feasible due to the curvature of the bevel
Solution Approach 1:
The patent transitions from collinear transmission/reflection measurements to a non-collinear geometry where the transmitter and receiver are positioned at different locations and angles relative to the pipe bevel. This dimensional change in measurement geometry allows the THz waves to properly interact with the weld region despite the curved bevel surface, enabling defect detection that was previously impossible with traditional methods
2Productivity
If butt weld fusion process is used to join pipe sections, then pipe installation is efficient, but defects such as contaminants, non-ideal pressure, and cold fusion can compromise joint integrity and are difficult to detect
Solution Approach 1:
The THz inspection system is applied immediately or soon after the butt fusion welding process to detect defects before the piping is installed in the field. This preliminary detection allows for identification of contaminants, pressure issues, and cold fusion problems while the pipe is still accessible, preventing future failures without requiring rework or excavation
Solution Approach 2:
The patent replaces destructive testing methods or mechanical inspection approaches with non-destructive THz spectroscopy and imaging. The THz waves penetrate the pipe material and weld joint to detect defects without physically damaging the pipe, maintaining joint integrity while providing reliable defect detection
3Measurement precision
If THz inspection is applied to detect defects in pipe joints, then defect detection capability is improved, but the inspection system complexity increases due to non-collinear geometry requirements
Solution Approach 1:
The patent applies THz inspection specifically targeted at the weld region and bevel area of the pipe joint, rather than attempting to inspect the entire pipe uniformly. The non-collinear transmitter and receiver positions are optimized for the local geometry of the weld zone, allowing effective defect detection in the critical region while simplifying the overall inspection setup compared to a comprehensive full-pipe inspection system
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 immediate detection of pipe defects post-fusion, ensuring the longevity of PE gas pipes, preventing gas leaks, and eliminating the need for expensive excavation repairs by providing a non-destructive means to assess pipe joint integrity and stress.
Implementation Method 1
The transmitter is oriented to transmit Terahertz (THz) waveform pulses towards at least one of an outer surface of a pipe or an inner surface of the pipe
Implementation Method 2
The receiver is oriented to receive reflected Terahertz (THz) waveform pulses from at least one of the outer surface of the pipe, the inner surface of the pipe, the pipe joint
Implementation Method 3
The exemplary systems ensure PE pipe joint integrity by utilizing Terahertz (THz) spectroscopy and imaging for non-destructive evaluation or testing of PE pipe joints
Implementation Method 4
The exemplary THz NDE methods can also be used to measure stresses in the pipes and pipe joints that affect pipe joint stability
Data Source
AI summary
An example system for detecting pipe defects is provided. The system includes a transmitter, a receiver and a processing device. The transmitter is oriented to transmit Terahertz (THz) waveform pulses towards at least one of an outer surface of a pipe or an inner surface of the pipe. The receiver is oriented to receive reflected Terahertz (THz) waveform pulses from at least one of the outer surface of the pipe or the inner surface of the pipe. The processing device configured is to receive as input the Terahertz (THz) waveform pulses transmitted from the transmitter and the reflected Terahertz (THz) waveform pulses received by the receiver and, based on the received input, determine if a defect in the pipe exists.