Flexible Connection for Large Diameter Pipe Articulation

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Solution Overview

Problem

Existing flexible connections between large diameter fluid conveying pipes and supporting structures, such as platforms, fail to effectively accommodate relative motions and pressure variations, leading to excessive bending moments and strain, particularly in applications like Ocean Thermal Energy Conversion (OTEC) systems where pipes are subject to wave and wind forces.

Innovation Solution

A flexible connection system that includes an articulation mechanism allowing roll and pitch movements while restricting yaw, combined with a fluid impermeable bellows to contain internal and external pressures, ensuring the connection can adapt to both internal and external fluid pressures across the joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid connection is used between the pipe and platform, then structural strength is improved, but the ability to accommodate relative motions due to waves and wind is lost

Engineering Contradiction:
Improvestructural strengthVSAvoidability to accommodate relative motions
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The connection system employs a dynamic articulation mechanism with multiple degrees of freedom that allows the pipe to move relative to the platform in response to wave and wind forces. The articulation mechanism includes spherical joints and hinges that enable rotational movements while maintaining structural integrity, transforming the rigid connection into a dynamically adaptable system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes flexible bellows components made of elastomeric or metallic materials that can expand and contract to accommodate relative displacements between the pipe and platform. These flexible elements maintain sealing and structural strength while allowing the necessary movements due to environmental forces.

Inventive Principle:
Principle #30Flexible shells and thin films

2Adaptability or versatility

If a flexible connection is used to accommodate motions, then adaptability is improved, but pressure containment capability deteriorates

Engineering Contradiction:
Improveability to accommodate relative motionsVSAvoidpressure containment
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The patent employs flexible bellows with integrated sealing elements that maintain pressure containment while accommodating relative motions. The bellows are designed with convoluted structures that can expand and contract axially and radially, maintaining the pressure barrier between the internal fluid and external environment during articulation movements.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The connection system uses composite structures combining rigid articulation mechanisms with flexible sealing components. The articulation mechanism provides structural strength and motion capability, while the flexible bellows and sealing elements maintain pressure containment, creating a composite system that satisfies both requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If the pipe diameter is increased to reduce friction losses, then energy efficiency is improved, but the pipe becomes more susceptible to bending and vibration

Engineering Contradiction:
Improvefriction lossesVSAvoidpipe bending and vibration resistance
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The articulation mechanism acts as a dynamic support system that reduces bending moments and vibrations in large diameter pipes. By allowing controlled articulation movements, the mechanism prevents the accumulation of stress and vibration that would otherwise occur in rigidly supported large diameter pipes, maintaining both energy efficiency and structural stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flexible connection acts as an intermediary element between the pipe and platform, absorbing and isolating vibrations and bending forces. This intermediary mechanism protects the large diameter pipe from excessive mechanical stresses while maintaining the hydraulic efficiency required for energy-effective fluid transport.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables the flexible connection to accommodate relative motions between pipes and platforms without imposing excessive strain, while maintaining pressure integrity, thus reducing friction losses and ensuring reliable operation in dynamic environments like OTEC systems.

Implementation Method 1

The flexible bellows is configured to contain internal and/or external fluid pressure across the flexible connection

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2971915B1Large diameter pipe flexible connection
Publication Date: 2019.06.26 LOCKHEED MARTIN CORP
  • EP2971915B1 patent drawingFigure 1
  • EP2971915B1 patent drawingFigure 2
  • EP2971915B1 patent drawingFigure 2A

AI summary

A flexible connection is described for use between a vertical, large diameter cold water conveying pipe and a floating platform that supports the cold water conveying pipe or another pipe to permit the pipe and the platform to rotate in roll and pitch directions relative to one another without imposing excessive bending moments or strain on the cold water pipe. The flexible connection also contains internal and external pressure across the connection. The flexible connection includes an articulation mechanism that interconnects the vertical cold water conveying pipe and the platform or a pipe on the platform, and a flexible, fluid impermeable bellows.