Polymer Liner Bonding in Pipes to Prevent Slippage and Leaks
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Solution Overview
Problem
In the manufacturing of polymer-lined pipes, there is a risk of liner slippage and potential damage during welding due to residual elastic stresses and imperfect contact between the liner and the host pipe, which can lead to leaks and instability in the pipeline.
Innovation Solution
A method involving die drawing of the liner pipe, followed by the strategic application of adhesive to specific locations between the liner and host pipes to enhance bonding, using shims to maintain radial expansion and ensure a tight fit, thereby preventing liner retraction and ensuring a continuous, smooth inner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If die drawing is used to install the liner pipe, then the liner pipe can be inserted into the host pipe, but residual elastic stresses cause liner slippage and imperfect contact
Solution Approach 1:
An adhesive is introduced as an intermediary substance between the liner pipe and host pipe to bond them together. The adhesive compensates for the imperfect contact and residual elastic stresses, preventing liner slippage and ensuring reliable connection without requiring perfect initial contact
2Reliability
If the liner pipe is expanded to bond with the host pipe, then contact is improved, but welding heat can damage the polymer liner
Solution Approach 1:
The liner pipe is pre-bonded to the host pipe using adhesive before the welding operation. This preliminary bonding action secures the liner in position and protects it from welding heat damage, allowing subsequent welding of the metal host pipe without compromising the polymer liner integrity
3Reliability
If adhesive is applied to the entire liner surface, then bonding is maximized, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of applying adhesive to the entire liner surface, the invention applies adhesive only at specific critical locations where bonding is most needed. This localized approach maintains reliable bonding while significantly reducing manufacturing complexity and adhesive material costs
4Manufacturing precision
If the liner pipe is left protruding for positioning, then longitudinal alignment is achieved, but the liner is vulnerable to damage and leaks
Solution Approach 1:
The liner pipe is protruded during the die drawing process to achieve proper longitudinal positioning and alignment with the host pipe ends. Once positioned correctly, the liner is bonded with adhesive and then the protruding portions are cut back. This preliminary protrusion allows precise positioning before final trimming to eliminate vulnerable exposed sections
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 mitigates liner slippage and ensures a secure bond between the liner and host pipe, preventing leaks and maintaining the integrity of the pipeline during assembly and operation.
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
Implementation Method 3
the liner pipe expands radially outwardly to press against the inner surface of the host pipe
Data Source
Figure 1~3
Figure 4~6
Figure 7a~8
AI summary
A method of manufacturing a length of lined pipe comprises inserting 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 may be inserted into the gap between the pipes. A portion of the liner pipe inboard of the shims may 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.