Pipe Inspection Sequence for Internal and External Flaw Detection
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Solution Overview
Problem
Current non-destructive testing methods for long pipes, such as those used in airbag inflators, face challenges in efficiently inspecting both internal and external surfaces, leading to high rejection rates and wastage due to limitations in scanning flexibility and the inability to detect internal discontinuities effectively.
Innovation Solution
A method and system that involves cutting the pipe to length and performing both internal and external non-destructive tests, including eddy current, magnetic flux leakage, and laser visual tests, with demagnetization steps to avoid interference, allowing for comprehensive inspection and reduced rejection rates by varying thresholds based on the pipe's longitudinal location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inspection is performed on long stock pipe before cutting, then productivity is maintained at 1.5 metres per second, but the ability to detect internal surface discontinuities is limited
Solution Approach 1:
The inspection process is segmented into two distinct phases: (1) external surface inspection of long stock pipe at high speed using eddy current and ultrasonic testing, and (2) internal surface inspection of cut pipes using borescopes or internal sensors. This segmentation allows each phase to be optimized independently - maintaining high productivity for external inspection while enabling precise internal discontinuity detection after cutting.
2Speed
If only external surface scanning is performed, then inspection speed is maintained, but internal surface flaws remain undetected
Solution Approach 1:
External surface inspection is performed as a preliminary action on long stock pipe before cutting, using high-speed eddy current and ultrasonic testing. This preliminary inspection filters out pipes with external defects, and only pipes passing this stage proceed to cutting and subsequent internal inspection, thereby maintaining overall inspection speed while ensuring internal flaws are not missed.
Solution Approach 2:
The inspection system uses nested approaches where external surface testing (eddy current, ultrasonic) is performed on the outer surface, and internal surface testing (borescope, internal sensors) is nested within the pipe after cutting. This nested structure allows comprehensive inspection of both surfaces without requiring simultaneous complex instrumentation.
3Reliability
If strict inspection criteria are applied to cut pipes, then safety is improved, but rejection rate and wastage increase significantly
Solution Approach 1:
The inspection system applies different quality criteria to different locations and surfaces of the pipe. External surface inspection uses eddy current and ultrasonic testing with specific acceptance criteria, while internal surface inspection uses borescope or internal sensors with potentially different criteria. This localized quality approach ensures safety requirements are met for each critical area without uniformly rejecting pipes that might be acceptable in less critical regions.
Solution Approach 2:
The system performs partial inspection on long stock pipe (external surfaces only at high speed) and complete inspection on cut pipes (both internal and external surfaces). This partial/excessive action approach ensures that pipes meeting safety criteria are not rejected, while maintaining high productivity by not applying full inspection rigor to every segment of long stock pipe.
4Measurement precision
If both internal and external tests are performed on cut pipe, then testing accuracy is improved, but inspection time increases
Solution Approach 1:
External surface inspection is performed as a preliminary action on long stock pipe before cutting using high-speed automated systems. Pipes that pass this preliminary external inspection are then cut and subjected to internal surface inspection. This preliminary filtering reduces the number of pipes requiring time-consuming internal inspection, thereby improving overall testing accuracy without proportionally increasing total inspection time.
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 approach improves the accuracy of pipe testing, reduces wastage by identifying flaws more effectively, and optimizes the testing process by performing slower laser visual tests only on pipes that pass earlier tests, enhancing efficiency and productivity.
Implementation Method 1
performing a first non-destructive test on an inner surface of the cut pipe; performing a second non-destructive test on an outer surface of the cut pipe
Implementation Method 2
performing a magnetic flux leakage test. A magnetic flux leakage test may identify different discontinuities and/or flaws that are not identified by other types of non-destructive tests
Implementation Method 3
both be a laser visual test (also known as a visual laser test)
Data Source
AI summary
A method of testing of a component of a system that includes a pipe of a first length is provided. The method includes the steps of: providing a second length of stock pipe, the second length being greater than the first length; cutting the stock pipe to the first length to produce a cut pipe; inspecting the cut pipe using a non-destructive inspection technique. The non-destructive inspection technique includes the steps of: performing a first non-destructive test on an inner surface of the cut pipe; performing a second non-destructive test on an outer surface of the cut pipe. The method further includes the step of rejecting the cut pipe if the step of inspecting the pipe identifies a flaw.