Unbonded Flexible Pipe End-Fitting for Leak Current Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical heated unbonded flexible pipes in offshore and subsea oil and gas transportation face safety risks due to unintended electrical polarization and potential leak currents, especially during electrical failures, which can lead to hazardous situations and pipe blockages.
Innovation Solution
The assembly of an end-fitting with three electric zones, where the first and second zones are electrically connected to the pipe's conductive layers and insulated from each other, and the third zone is connected to ground, providing an electrically insulated barrier and ensuring safe operation by preventing unintended current paths and grounding the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high voltage and high current are used to heat the pipe, then heating efficiency is improved, but safety risks increase due to unintended electrical polarization and potential leak currents
Solution Approach 1:
The end-fitting is divided into three electrically isolated zones: a first electric zone connected to the first electrically conductive layer, a second electric zone connected to the second electrically conductive layer, and a third electric zone connected to ground. These zones are electrically insulated from each other, segmenting the electrical paths to prevent unintended current flow while maintaining efficient heating capability.
Solution Approach 2:
Electrical insulation is introduced as an intermediary between the first and second electric zones, and between these zones and the third ground-connected zone. This intermediary prevents direct electrical contact and potential hazard propagation while allowing the heating function to operate at high voltage and current.
2Strength
If the end-fitting is made rigid from steel or metal to withstand internal pressure and transfer axial forces, then mechanical strength is improved, but adaptability to flexible pipe decreases
Solution Approach 1:
The end-fitting employs different materials and properties in different zones: rigid metallic components provide structural strength and pressure containment, while electrical insulation layers provide flexibility and electrical isolation. This local differentiation allows the end-fitting to simultaneously achieve high mechanical strength and compatibility with flexible pipe requirements.
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 configuration enhances safety by preventing electrical hazards and maintaining system equilibrium, reducing the risk of pipe blockages and allowing for efficient heating while ensuring operational safety during nominal and fault conditions.
Implementation Method 1
The unbonded flexible pipe comprises a first electrically conductive layer and a second electrically conductive layer, where the first electrically conductive layer is electrically insulated from the second electrically conductive layer
Implementation Method 2
the end-fitting comprises a first electric zone electrically connected with the first electrically conductive layer, and a second electric zone electrically connected with the second electrically conductive layer, the first electric zone is electrically separated from the second electric zone
Implementation Method 3
the end-fitting comprises a third electric zone, said third electric zone being electrically separated from first electric zone and the second electric zone
Data Source
AI summary
An assembly comprising an end-fitting and an unbonded flexible pipe comprising several layers. The unbonded flexible pipe has an end-part entering the end-fitting at the front end and the layers of the unbonded flexible pipe being terminated in the end-fitting. The unbonded flexible pipe further comprises a first electrically conductive layer and a second electrically conductive layer, where the first electrically conductive layer is electrically insulated from the second electrically conductive layer. The end-fitting comprises a first electric zone electrically connected with the first electrically conductive layer, and a second electric zone electrically connected with the second electrically conductive layer, the first electric zone is electrically separated from the second electric zone, and the end-fitting comprises a third electric zone, the third electric zone being electrically separated from first electric zone and the second electric zone.