Flexible Pipeline Defect Detection via Dual Sensor System
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Solution Overview
Problem
Flexible pipes used in deep and ultra-deep water environments are prone to defects such as seawater ingress due to corrosion of metal armour layers, which can compromise structural integrity, and existing detection methods are hazardous and inefficient, particularly requiring periodic visual inspections.
Innovation Solution
A pipeline apparatus featuring a Fibre In Metal Tube (FIMT) with an optical sensor and electrical sensor system that detects scattered light and impedance variations to identify potential defects within the pipe body, allowing for timely repair or replacement without visual inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thicker and stronger materials are used to improve armour layer performance, then strength and reliability are improved, but weight and material cost increase
Solution Approach 1:
The patent employs composite armour layer structures combining metal wires with polymer coatings or jackets. The metal wires (steel or alloy) provide tensile and pressure resistance, while the polymer layers (such as polyethylene or polypropylene) provide corrosion protection and additional strength. This composite approach achieves high strength-to-weight ratio, improving armour layer performance without proportionally increasing weight.
Solution Approach 2:
The patent optimizes wire diameter, winding patterns, and material properties to achieve desired strength characteristics. By carefully selecting wire gauge (e.g., 0.5mm to 2mm), lay angles, and layer configurations, the design achieves adequate strength with minimized material usage and weight.
2Strength
If thicker and stronger materials are used to improve armour layer performance, then strength and reliability are improved, but material cost increases
Solution Approach 1:
The composite structure allows use of cost-effective polymer materials combined with optimized metal wire usage. The polymer layers can be extruded continuously, reducing manufacturing cost compared to solid metal construction, while still providing adequate strength and corrosion protection.
Solution Approach 2:
The patent optimizes wire diameter and material selection to balance strength requirements with material cost. By selecting appropriate wire gauges and material grades, and optimizing the armour layer configuration, the design achieves required performance at minimized material cost.
3Measurement precision
If visual inspection methods are used to detect defects, then detection capability is provided, but safety risk and operational efficiency deteriorate
Solution Approach 1:
The patent replaces mechanical visual inspection with electromagnetic sensing methods. Electrical sensors measure changes in electrical properties (conductivity, capacitance) of the armour layers to detect corrosion, water ingress, or wire breaks. Optical sensors detect surface defects, deformations, or temperature anomalies. This substitution eliminates the need for personnel to physically access and visually inspect the pipe, removing safety risks while maintaining or improving detection capability.
Solution Approach 2:
The patent introduces sensor systems as intermediaries between the pipe structure and the inspection process. These sensors (electrical or optical) act as mediators that detect defects through physical or electromagnetic field interactions without requiring direct visual contact, thereby eliminating safety hazards associated with close proximity inspection.
4Measurement precision
If periodic visual inspection is used, then defect detection is possible, but time loss and operational efficiency worsen
Solution Approach 1:
The patent implements continuous monitoring systems where sensors are permanently installed on or within the pipe structure. These sensors continuously measure electrical or optical parameters, providing real-time defect detection without interruption to pipe operation. This eliminates the periodic shutdowns and time losses associated with scheduled visual inspections, enabling uninterrupted operation while maintaining constant surveillance for defects.
Solution Approach 2:
By replacing manual visual inspection with automated sensor systems, the patent eliminates the time-consuming human inspection process. Electrical and optical sensors provide rapid, automated defect detection that occurs continuously or on-demand without requiring operational shutdowns, thereby eliminating time loss while maintaining detection capability.
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 dual sensor system effectively detects breaches and temperature changes along the flexible pipe, providing early warning of defects and improving the reliability of pipe integrity monitoring, reducing the risk of structural failure and material costs associated with thicker materials.
Implementation Method 1
an optical sensor coupled to a first end of the optical fibre, the optical sensor being arranged to inject optical pulses into the optical fibre and to detect scattered or reflected light
Implementation Method 2
an optical sensor coupled to a first end of the optical fibre, the optical sensor being arranged to inject optical pulses into the optical fibre and to detect scattered or reflected light
Implementation Method 3
an electrical sensor coupled to a first end of the metal tube and to detect variation of an electrical impedance between the first end of the metal tube and a separate terminal; wherein impedance variation, is indicative of an Earth fault along the FIMT metal tube
Data Source
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AI summary
A pipeline apparatus comprising a flexible pipe body and a detection apparatus. The flexible pipe body includes an optical fibre extending at least partially along the length of the flexible pipe body, the optical fibre being encased in a metal tube. The detection apparatus comprises an optical sensor and an electrical sensor. The optical sensor is coupled to a first end of the optical fibre, the optical sensor being arranged to inject optical pulses into the optical fibre and to detect scattered or reflected light. The electrical sensor is coupled to a first end of the metal tube and to detect variation of an electrical impedance between the first end of the metal tube and a separate terminal. Variation of the scattered or reflected light, or impedance variation, is indicative of a potential pipe body defect.