Liner Pipe Leak Testing Under Tension
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Solution Overview
Problem
Current methods for testing the integrity of polymer-lined pipelines are inefficient and unreliable, often requiring extensive time and resources, and are challenging to perform on internal coatings due to limited access.
Innovation Solution
A method and apparatus that temporarily reduce the external diameter of the pipe lining using dies or rollers, allowing for a leak test to be conducted before releasing tension, which can include creating an enclosed volume for pressure or ultrasound monitoring to detect leaks, enabling the pipe lining to be easily removed or replaced if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liner pipe is allowed to revert fully before testing, then the liner contacts the host pipe inner surface providing corrosion protection, but the testing process becomes slow and time-consuming
Solution Approach 1:
The patent applies preliminary action by performing the integrity test on the liner pipe while it is still in the unreverted state, before the liner is allowed to expand and contact the host pipe. This enables testing to occur during the installation process itself, rather than after reversion, thereby dramatically reducing the total time required while maintaining testing reliability.
2Reliability
If water flooding is used to test for leaks after reversion, then leak detection is possible, but the process requires producing and disposing of large amounts of water and takes several days
Solution Approach 1:
The patent replaces the mechanical water flooding system with a pneumatic or electronic testing system. Instead of using water to detect leaks, the system uses air pressure differential measurement or electromagnetic signals (such as eddy current testing) to detect leaks in the liner pipe while it is in the unreverted state, eliminating the need for large volumes of water and multi-day testing procedures.
3Ease of repair
If the liner pipe is under tension during installation, then the liner can be easily removed if defective, but leak testing cannot be performed until after reversion
Solution Approach 1:
The patent performs the integrity test as a preliminary action while the liner pipe is still under tension and in the unreverted state. This timing allows the liner to be easily removed if defective, while simultaneously enabling reliable leak detection before the liner is allowed to revert and become difficult to remove.
4Measurement precision
If traditional Holiday or Continuity tests are used on external coatings, then discontinuities can be detected, but these methods are extremely difficult to apply to internal coatings with limited access
Solution Approach 1:
The patent replaces traditional electrical Holiday or Continuity tests with alternative testing methods suitable for internal coatings. The system uses air pressure differential measurement or electromagnetic eddy current testing that can be performed through the liner pipe wall from the interior side, eliminating the need for external access and making the testing feasible for internal coatings where direct access is limited.
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 allows for rapid and accurate integrity testing of pipe linings while the pipe is still under tension, enabling immediate remedial action and reducing testing time from days to hours, improving detection accuracy and efficiency compared to post-reversion methods.
Implementation Method 1
the memory characteristics of the material of the liner pipe cause it to undergo radial expansion as it reverts towards its original dimensions
Implementation Method 2
creating an enclosed volume within the pipe lining, at least partially evacuating the enclosed volume, and monitoring the pressure within the enclosed volume
Implementation Method 3
monitoring for ultrasound signals within the enclosed volume, in an annular space between the pipe lining and the host pipe
Data Source
AI summary
Methods and apparatus enable the integrity of a liner pipe to be quickly and effectively tested in the field, while permitting rapid removal and replacement of the liner pipe if it is compromised. The liner pipe is leak tested prior to reversion, after being pulled through a host pipe to be lined via a swaging die and while the liner pipe is still under tension. If the liner pipe exhibits a leak, it can be removed from the liner pipe immediately and, importantly, before it has expanded to contact the host pipe. Leak testing apparatus includes a packer, which seals the opposite end of the liner pipe from the end which is pulled, creating a contained fluid volume upon which the leak test is performed. The leak test may be a pressure test or a vacuum test or any other suitable test.