Flexible Pipe Flooding Detection via Ultrasonic Polarity
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Solution Overview
Problem
Existing methods for detecting flooding in flexible pipes, particularly those used for hydrocarbon transport across bodies of water, are imprecise under external pressure conditions, failing to distinguish between flooded and dry annular spaces due to ultrasound propagation changes.
Innovation Solution
A non-intrusive ultrasonic method analyzing the polarity of reflected signals at the interface between the external sheath and the internal space, using a focused ultrasound beam with a central frequency between 1.5 MHz and 5 MHz, and comparing the signals to a database to determine the nature of the medium, allowing for reliable detection of flooding regardless of external pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ultrasonic sounding technique is used to detect flooding in flexible pipes, then non-intrusive inspection capability is provided, but under external pressure conditions the method fails to distinguish between flooded and dry annular spaces due to ultrasound propagation changes
Solution Approach 1:
The patent changes the parameter being measured from ultrasound amplitude (which is affected by external pressure) to ultrasound signal polarity (which remains consistent). By analyzing the polarity of reflected ultrasonic signals rather than their amplitude, the method maintains detection accuracy under varying external pressure conditions while preserving non-intrusive inspection capability.
Solution Approach 2:
The patent introduces polarity analysis as an intermediary measurement approach. Instead of directly measuring flooding conditions through amplitude (which is influenced by pressure), the method uses polarity as an intermediate indicator that is insensitive to pressure changes, thereby enabling accurate flooding detection under external pressure.
2Reliability
If annular test with vacuum creation is used to measure tidal volume, then flooding detection capability is provided, but the volume measurement is imprecise and cannot determine the presence and depth of flooded areas
Solution Approach 1:
The patent replaces the mechanical vacuum-based volume measurement system with an ultrasonic acoustic field-based detection system. This substitution eliminates the need for physical vacuum creation and volume measurement, using instead the polarity characteristics of reflected ultrasonic signals to detect flooding presence and depth with higher precision.
Solution Approach 2:
The patent uses ultrasonic wave polarity as an intermediary indicator to infer flooding conditions. Rather than directly measuring volume (which is imprecise), the method analyzes the polarity of reflected signals as an intermediate step that provides more accurate information about flooding presence and depth.
3Use of energy by moving object
If ultrasound propagation relies on coupling medium property, then ultrasound propagation capability is improved, but under external pressure the coupling medium becomes unnecessary and the inspection method cannot distinguish flooded from dry annulus
Solution Approach 1:
The patent changes the detection parameter from ultrasound propagation capability (which depends on coupling medium and is affected by pressure) to ultrasound signal polarity (which is independent of coupling medium and pressure conditions). This parameter change enables consistent flooding detection whether or not a coupling medium is present.
Solution Approach 2:
The patent converts the harmful effect of external pressure removing the coupling medium into a beneficial opportunity. By using polarity analysis, the method works equally well whether a coupling medium is present or absent, and whether the annulus is flooded or dry, turning the pressure-induced removal of the coupling medium from a problem into a non-issue.
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 accurate and reliable detection of flooding in flexible pipes under varying external pressures, distinguishing between dry and flooded annular spaces, ensuring the integrity of the pipe's armor layers and preventing corrosion.
Implementation Method 1
sending an ultrasonic signal from outside the outer sheath onto a region to be controlled of the outer sheath, and receiving the reflected signal at the interface between the region to be controlled of the outer sheath and the internal space opposite the region to be controlled of the outer sheath
Implementation Method 2
sending an ultrasonic signal from outside the outer sheath onto a region to be controlled of the outer sheath
Implementation Method 3
comprising: analysis of the polarity of the signal reflected at the interface and determination, as a function of the analyzed polarity, of at least the nature of the medium at the interface
Data Source
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Figure 3~6
AI summary
The present invention relates to a method of checking a flexible line comprising at least one armour layer (24, 25) surrounded by an external sheath (30), the external sheath (30) delimiting an internal space (33) receiving the armour layer (24, 25) and comprising at least one medium (M) at the interface between the external sheath (30) and the internal space (33). The method comprises: - the dispatching of an ultrasound signal over a region to be checked of the external sheath (30), and - the receiving of the signal reflected at the interface between the region to be checked of the external sheath (30) and the internal space (33) opposite the region to be checked of the external sheath (30). The method comprises, furthermore, the analysis of the polarity of the signal reflected and the determination, as a function of the polarity analysed, of at least the nature of the medium (M) at the interface.