End-Fitting Electrical Connection for Unbonded Flexible Pipe

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Solution Overview

Problem

Existing unbonded flexible pipes used in subsea applications for transporting hydrocarbons lack an efficient means to connect their internal and external armour layers to an external electrical power source for heating systems, limiting the effective operation of electric heating systems.

Innovation Solution

The assembly comprises an end-fitting with an annular channel and flange, featuring connection points to the internal and external armour layers, connected via electrical wiring and housed in a protective enclosure to facilitate electrical connection from an external power source, ensuring moisture and gas exclusion and compliance with ATEX standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the end-fitting is equipped with means for electrical connection to enable heating systems, then the heating system can receive electric power from external power source, but the end-fitting structure becomes more complex and requires additional protective measures

Engineering Contradiction:
Improveelectrical connection capabilityVSAvoidend-fitting structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The connection points for the electrical power source are mounted in a housing that is adapted to an outer surface-part in the annular channel of the end-fitting. This nesting approach integrates the electrical connection components within the existing annular channel structure, reducing overall complexity while enabling electrical connectivity for heating systems

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If electrical connection means are added to the end-fitting, then heating systems can be operated, but the risk of moisture and gas ingress increases

Engineering Contradiction:
Improveheating system operationVSAvoidmoisture and gas ingress
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The housing for the connection points is designed as a sealed protective enclosure that can be integrated into the end-fitting. This housing acts as a barrier against moisture and gas ingress, protecting the electrical connection components while enabling heating system operation in harsh subsea environments

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The housing creates a protected environment for the electrical connection components, isolating them from harmful external factors such as moisture and gas. This protective enclosure ensures that the electrical connections remain functional and safe in the subsea environment

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Ease of manufacture

If connection points for electrical power source are integrated in the annular channel, then electrical wiring is simplified, but the housing and mounting requirements increase

Engineering Contradiction:
Improveelectrical wiring integrationVSAvoidhousing and mounting structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The annular channel in the end-fitting serves multiple functions: it provides structural support, enables mechanical termination of pipe layers, and accommodates the housing for electrical connection points. This multi-functionality simplifies the overall design by utilizing existing structural elements for electrical integration purposes

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

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 solution enables reliable and safe electrical connection for heating systems in unbonded flexible pipes, enhancing operational efficiency and longevity by allowing direct external power supply to the pipe's armour layers, thus improving the heating system's performance and reducing the risk of explosion.

Implementation Method 1

The end-fitting comprises means for connecting the internal armour layer to an external electrical power source

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3334967B1An assembly comprising an end-fitting and an unbonded flexible pipe
Publication Date: 2020.03.11 NAT OILWELL VARCO DENMARK
  • EP3334967B1 patent drawingFigure 1
  • EP3334967B1 patent drawingFigure 2
  • EP3334967B1 patent drawingFigure 3

AI summary

The present invention relates to an assembly (1) comprising an end-fitting (2) and an unbonded flexible pipe (3) having a length and a longitudinal axis, the flexible pipe (3) comprising, from the inside and out, an interna] armour layer (1.0), an internal pressure sheath (1.1 ), at least one external armour layer (12) and an outer sheath (13), the first end of the unbonded flexible pipe (3) being terminated in the end-fitting (2), and the end-fitting (2) comprising means for connecting the internal armour layer (10) to an external electrical power source. The means comprise connection points (20) to the internal armour layer (10) in the unbonded flexible pipe (3) and connection points (23 ) to the electrical power source wherein the connection points (23) for the electrical power source are mounted in a hou sing (26) adapted to an outer surface-part of the end-fitting (2).