Polymer Liner Bonding in Steel Pipes to Prevent Slippage
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Solution Overview
Problem
The challenge in the oil and gas industry is to maintain a continuous, corrosion-resistant internal surface in polymer-lined steel pipes during welding, as the heat from welding can damage the polymer liner, and there is a risk of liner slippage and collapse due to residual elastic stresses and micrometric gaps between the liner and the host pipe.
Innovation Solution
A method involving die drawing to radially contract the polymer liner pipe, insert injectors to apply adhesive between the liner and host pipe, and then expand the liner to bond it securely, using shims to maintain the annular gap for adhesive injection and ensure a tight fit, thereby preventing liner retraction and ensuring a strong bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the polymer liner pipe is radially contracted to fit inside the host pipe, then the liner can be inserted into the host pipe, but micrometric gaps form between the liner and host pipe allowing liner slippage
Solution Approach 1:
Adhesive is introduced as an intermediary substance between the polymer liner pipe and the host pipe. The adhesive fills the micrometric gaps that form during radial contraction and creates a bonding interface that prevents liner slippage while maintaining the tight fit achieved through die drawing.
Solution Approach 2:
Adhesive is applied to the liner pipe surface before the radial contraction process. This preliminary application ensures that when the liner is contracted and inserted into the host pipe, the adhesive is already in position to fill gaps and prevent slippage, rather than requiring post-installation adjustments.
2Ease of manufacture
If welding is performed to join pipe lengths, then the steel pipes can be connected, but the polymer liner is damaged by welding heat
Solution Approach 1:
The adhesive layer serves as a thermal intermediary between the host pipe and the polymer liner during welding operations. It provides thermal isolation that protects the polymer liner from direct exposure to welding heat while still maintaining the structural bond between the liner and host pipe.
3Reliability
If adhesive is applied to bond the liner to the host pipe, then liner slippage is prevented, but the annular gap must be maintained for adhesive injection
Solution Approach 1:
The annular gap is deliberately maintained during the radial contraction process through preliminary positioning and control of the die drawing operation. This pre-maintained gap provides ready access for adhesive injection without requiring additional complex positioning systems or post-contraction adjustments.
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 effectively prevents liner slippage and ensures a strong, continuous bond between the liner and host pipe, maintaining the corrosion-resistant surface and preventing retraction during welding and installation of liner bridges, thus ensuring a stable and leak-proof pipeline.
Implementation Method 1
To reduce its outer diameter by elastic deformation, the liner pipe is pulled through an annular swage die
Implementation Method 2
During reversion, the elasticity of the polymer liner pipe material draws the protruding end portions of the liner pipe back into the corresponding ends of the host pipe. Simultaneously, the liner pipe expands radially outwardly to press against the inner surface of the host pipe.
Data Source
AI summary
A method of manufacturing a length of lined pipe inserts a radially contracted liner pipe into an outer host pipe. Injector needles are inserted through an end of the outer pipe into an annular gap between the pipes. Adhesive is injected between the pipes at locations inboard of the end of the outer pipe. After withdrawing the injectors, at least a portion of the liner pipe is expanded to close the gap and to bond the pipes together via the injected adhesive. Shims can be inserted into the gap between the pipes. A portion of the liner pipe inboard of the shims can be expanded radially while the shims constrain local radial expansion of an outboard portion of the liner pipe to maintain the gap for accommodating the injectors. Withdrawing the shims after injecting the adhesive allows radial expansion of the outboard portion to close the gap between the pipes.