Liner Bridge Terminal Sealing for Electrofusion Lined Pipes
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Solution Overview
Problem
Existing electrofusion methods for joining polymer-lined metal pipes face challenges in sealing activation terminals, leading to potential leaks and corrosion due to the exposure of electrical leads, which compromises the integrity of the pipeline.
Innovation Solution
A liner bridge design with radially extending and complementary formations on the terminal and bore, respectively, creates a sealing interface that includes a contact end with a taper and a radially inward deformation of the bore, along with an adhesive sealing mass, to ensure leak-tightness and prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrical leads are extended through the fitting to power heating coils, then electrofusion can be achieved, but leak paths are created allowing fluid migration and corrosion
Solution Approach 1:
The electrical activation system is extracted from the internal fluid environment by positioning terminals and heating coils on the external surface of the fitting, eliminating the leak path through the liner while maintaining electrofusion capability
Solution Approach 2:
A reach rod mechanism acts as an intermediary to transmit electrical activation signals from external terminals through the fitting wall to internal heating coils without creating permanent conductive pathways that would compromise seal integrity
2Ease of operation
If activation terminals are positioned inside the liner bridge, then electrofusion can be activated, but corrosive fluid can contact the steel outer pipe through the leads
Solution Approach 1:
Instead of positioning terminals inside the liner bridge as conventional practice, the invention inverts the arrangement by placing terminals on the external surface, thereby preventing fluid contact with electrical components while maintaining activation functionality
Solution Approach 2:
The liner bridge material forms a flexible barrier that isolates the electrical leads and heating coils from corrosive fluid, allowing the system to maintain both electrical functionality and corrosion protection
3Device complexity
If mechanical sealing is used at liner-bore interfaces, then assembly is simplified, but leak-tightness cannot be ensured
Solution Approach 1:
The sealing system combines mechanical interference fit of the terminal in the bore with adhesive bonding material, creating a composite sealing approach that ensures leak-tightness while maintaining reasonable assembly complexity
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
The design effectively seals the electrical terminals within the polymer liner, preventing fluid migration and corrosion, while maintaining the integrity of the pipeline by ensuring a leak-tight connection during the electrofusion process.
Implementation Method 1
current is passed through the heating coils via electrical leads that extend through the fitting. This causes the thermoplastic materials of the fitting and the parent liner near the coils to melt and fuse together
Implementation Method 2
current is passed through the heating coils via electrical leads that extend through the fitting. This causes the thermoplastic materials of the fitting and the parent liner near the coils to melt and fuse together
Data Source
AI summary
A liner bridge for a lined pipeline has bores extending through a tubular wall and terminals fitted in the bores, each terminal being exposed to an inward side of the wall for conducting electricity to an electrofusion element. A sealing interface between each terminal and its surrounding bore has one or more projecting formations of the terminal and at least one complementary formation of the bore engaged with the or each of the projecting formations. The interface can also include a sealing mass in the bore.