uRTP Pipe End Bonding for Stronger End Fitting Seals
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Solution Overview
Problem
Multilayer unbonded reinforced thermoplastic pipes face challenges in maintaining a secure connection between the end fitting and the pipe body, particularly in ensuring a seal and controlling strain transitions, which can lead to damage and loss of pressure containment capability due to the unbonded construction and swaging process.
Innovation Solution
The intermediate reinforcement layer is bonded to the fluid retaining liner only at the end portion of the pipe body, while remaining unbonded elsewhere, to stabilize the connection and reduce hoop strain, thereby enhancing the connection strength and flexibility of the pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the intermediate layer is unbonded to the fluid retaining liner throughout the entire pipe length, then the pipe maintains flexibility and ease of installation, but the connection strength at the end fitting is insufficient and strain transitions cause damage
Solution Approach 1:
The patent applies bonding locally only at the end portion of the pipe where the intermediate layer is bonded to the fluid retaining liner, while the remainder of the pipe maintains unbonded layers for flexibility. This local quality change resolves the contradiction by providing strong connection where needed without sacrificing overall pipe flexibility.
2Reliability
If the intermediate layer is bonded to the fluid retaining liner at the end portion, then the connection strength and seal are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the pipe into two distinct zones: a bonded end portion for reliable connection and an unbonded remainder for flexibility. This segmentation allows the manufacturing process to apply bonding only where necessary, reducing overall manufacturing complexity while maintaining reliability at the connection point.
3Strength
If the entire pipe is constructed with bonded layers, then the connection strength is maximized, but the pipe loses flexibility and becomes more difficult to install
Solution Approach 1:
The patent applies bonding only locally at the end portion rather than throughout the entire pipe length. This creates a local quality difference where the end portion has high strength for connection while the remainder maintains unbonded flexibility for ease of installation, resolving the contradiction between strength and operability.
Data Source
AI summary
Pipe body for an unbonded reinforced thermoplastic pipe (uRTP), the pipe body including a fluid retaining liner, an intermediate layer located radially outwardly of the fluid retaining liner, and a protective sheath located radially outwardly of the intermediate layer. The pipe body includes an end portion for terminating the pipe body at an end fitting. At the end portion, the intermediate layer is bonded to the fluid retaining liner. Away from the end portion, the intermediate layer remains unbonded to the fluid retaining liner.