Seawater Electrode Impedance Detection for Flexible Pipe Defects
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Solution Overview
Problem
Flexible pipes used in deep and ultra-deep water environments are prone to defects such as breaches in the outer seawater-resistant layer, leading to seawater ingress and potential structural integrity compromise, which existing detection methods often fail to accurately detect without hazardous visual inspections.
Innovation Solution
A detection apparatus comprising a seawater electrode and impedance monitor that measures impedance between the flexible pipe's metallic structural components and seawater, allowing for the location of defects by triangulation and using multiple frequencies to determine the distance and accuracy of breach detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual inspection methods are used to detect pipe defects, then defect detection capability is provided, but the inspection process becomes hazardous for deep water and ultra-deep water installations
Solution Approach 1:
The patent replaces mechanical visual inspection methods with an electrical impedance-based detection system. The apparatus uses impedance monitoring to detect changes in the pipe structure that indicate defects, eliminating the need for hazardous visual inspections in deep water environments while maintaining reliable defect detection capability
Solution Approach 2:
The patent introduces an electrical impedance monitoring system as an intermediary between the pipe structure and the detection process. By measuring impedance changes caused by defects rather than directly observing the pipe, the system enables safe remote detection while maintaining high reliability in detecting structural issues
2Strength
If thicker and stronger materials are used to improve armour layer performance, then load response and performance increase, but the weight of the flexible pipe increases
Solution Approach 1:
The patent changes the material parameters of the armour layers by using aluminium alloys with specific mechanical properties (yield strength ≥300 MPa, elongation ≥10%) instead of traditional thicker steel materials. This parameter change allows achieving the required strength and load response while significantly reducing the weight of the flexible pipe
3Strength
If thicker and stronger materials are used to improve armour layer performance, then load response and performance increase, but material costs increase appreciably
Solution Approach 1:
The patent optimizes the material parameters by selecting aluminium alloys with specific strength and elongation properties that provide the required armour layer performance at lower material costs. The use of lighter materials with appropriate mechanical properties reduces both the quantity of material needed and the overall cost compared to using thicker traditional materials
Solution Approach 2:
The patent employs composite material structures combining aluminium alloys with polymer layers in the armour construction. This composite approach achieves the required mechanical performance through the synergistic properties of different materials, reducing the need for excessive material quantity and lowering overall material costs while maintaining strength
4Productivity
If the flexible pipe operates in deeper water environments, then production fluid transport capability is improved, but the risk of pipe blockage and structural compromise increases
Solution Approach 1:
The patent changes the material parameters of the armour layers by using aluminium alloys with enhanced mechanical properties (yield strength ≥300 MPa, elongation ≥10%) that can withstand the extreme pressures and temperatures of deep water environments. This prevents structural compromise while maintaining production fluid transport capability
Solution Approach 2:
The patent uses composite material structures combining aluminium alloy armour layers with polymer protective layers. This composite construction provides both the strength needed to resist deep water pressures and the corrosion resistance required to prevent pipe blockage and structural failure, thereby improving reliability in deep water operations
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
Enables non-invasive, accurate detection of pipe defects in existing flexible pipe installations, preventing structural integrity loss by identifying breaches and allowing for timely repairs without the need for periodic visual inspections, thus ensuring the integrity and longevity of the pipe.
Implementation Method 1
an impedance monitor arranged to measure the impedance between a metallic structural component of the flexible pipe extending at least partially along the length of the flexible pipe and the seawater electrode
Data Source
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AI summary
A detection apparatus and method arranged to detect defects within a flexible pipe at least partially surrounded by seawater. The detection apparatus comprises a seawater electrode, an impedance monitor and a processor. The seawater electrode is arranged to be in contact with seawater surrounding at least part of a flexible pipe. The impedance monitor is arranged to measure the impedance between a metallic structural component of the flexible pipe extending at least partially along the length of the flexible pipe and the seawater electrode in response to an electrical test signal applied to the seawater electrode. The processor is arranged to determine the distance from the seawater electrode to a pipe defect electrically connecting the metallic structural component to seawater using the measured impedance.