Flexible Pipe Heating Test Using Armour Layer Temperature Profiling

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Solution Overview

Problem

There is a need for an effective method to test the heating system and temperature monitoring system of unbonded flexible pipes before they are released from the manufacturer, ensuring they meet predetermined specifications, and to validate their functionality during operation, as these systems are critical for the pipe's 20-year lifespan and mechanical protection.

Innovation Solution

A method involving connecting the metallic armour layer to an electric power source, sending an electric current through it, measuring the temperature shift using thermal sensors, and comparing the obtained temperature profile with a reference profile to determine if the pipe meets specified requirements, which can be performed before or during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional factory acceptance tests are used, then basic pipe functionality is verified, but heating system and temperature monitoring system cannot be tested

Engineering Contradiction:
Improveheating system functionalityVSAvoidtest system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the heating system test and temperature monitoring system test into a single integrated testing method. Electric current is sent through the metallic armour layer to generate heat, while thermal sensors simultaneously measure the temperature distribution. This merged approach allows both systems to be tested together using one test setup, resolving the contradiction between verifying heating system reliability and avoiding increased device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metallic armour layer serves multiple functions: it provides mechanical protection, enables heating through resistive heating when electric current passes through it, and acts as a conductor for the testing process. The thermal sensors simultaneously perform temperature monitoring and heating system validation. This multi-functionality allows the same components to be used for both operational purposes and testing purposes, eliminating the need for separate test equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate tests for heating system and temperature monitoring system are performed, then comprehensive validation is achieved, but testing time and complexity increase

Engineering Contradiction:
Improvetemperature monitoring accuracyVSAvoidtesting duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the heating system test and temperature monitoring system test into a single simultaneous operation. While electric current flows through the metallic armour layer to generate heat for validation, thermal sensors concurrently measure the temperature distribution along the pipe. This combined approach validates both systems in one testing cycle rather than requiring separate sequential tests, thereby reducing total testing time while maintaining comprehensive validation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The testing method maintains continuous useful action by having the heating and temperature monitoring occur simultaneously throughout the testing process. The electric current continuously generates heat while the thermal sensors continuously record temperature data, allowing both systems to be validated in real-time during the same operational period rather than requiring intermittent separate testing cycles.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If electric current is sent through metallic armour layer for heating test, then heating system is validated, but temperature distribution uniformity may be compromised

Engineering Contradiction:
Improveheating system validationVSAvoidtemperature distribution uniformity
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent employs thermal sensors distributed along the pipe to continuously monitor temperature distribution during the heating test. The measured temperature data is processed to generate a temperature profile that is compared against a reference temperature profile. This feedback mechanism allows real-time assessment of temperature uniformity, enabling validation of the heating system while detecting and identifying any non-uniform temperature distribution or hot spots that may develop during operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces physical inspection methods with electrical and optical measurement systems. Instead of mechanical thermometers or contact-based temperature measurement, the system uses thermal sensors and optical monitoring to non-invasively measure temperature distribution. This substitution allows for more precise and comprehensive temperature mapping without interfering with the heating process, enabling better validation of both heating performance and temperature uniformity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method allows for the simultaneous testing of the heating system and optical sensor functionality, ensuring the pipe's specifications are met, thereby validating its performance and identifying any potential issues such as hot spots that could damage the internal pressure sheath, thus ensuring the pipe's reliability and longevity.

Implementation Method 1

connecting the metallic armour layer to an electric power source sending an electric current through the metallic armour layer

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

measuring the shift in temperature in the flexible pipe by using the thermal sensor

Methodology Applied
Scientific EffectThermal detection: Thermography

Data Source

PatentEP3334965B9A method of testing an unbonded flexible pipe
Publication Date: 2021.04.07 NAT OILWELL VARCO DENMARK
  • EP3334965B9 patent drawingFigure 1
  • EP3334965B9 patent drawingFigure 2
  • EP3334965B9 patent drawingFigure 3~4

AI summary

The present invention discloses a method of testing an unbonded flexible pipe ( 3), The unbonded flexible pipe (1) has a length and a longitudinal axis (14) and comprises, from the inside and out, an internal armour layer (2), an internal pressure sheath (3), at least one external amour layer (4) and an outer sheath (5). At least one of the layers comprises an optical sensor (6) connected to an optical monitoring system (7) and at least one of the armour layers is a metallic and electrically conductive amour layer. The method makes it possible to test an electrical heating system and an optical sensor substantially simultaneously.