Removable Bore Liner for Subsea Hydraulic Coupling Galling

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Solution Overview

Problem

Subsea hydraulic coupling members experience galling issues due to repeated engagement and disengagement, leading to damage of sealing surfaces and potential leakage, especially under high pressure conditions, where the difference in material hardness between male and female coupling members is insufficient to prevent this problem.

Innovation Solution

A removable polymer sleeve bore liner with integral radial seals is introduced for the female undersea hydraulic coupling member, which can be secured using various means such as threads, ridges, or dovetail interfits, to minimize galling and protect the sealing surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If male and female coupling members are made from high-strength materials to withstand high pressure, then pressure resistance is improved, but galling of sealing surfaces worsens due to insufficient hardness difference between mating surfaces

Engineering Contradiction:

Improvepressure resistanceVSAvoidgalling of sealing surfaces

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

A bore liner is introduced as an intermediary component between the male coupling member and the female coupling member's bore. The bore liner has a softer material composition compared to the high-strength coupling members, creating the necessary hardness difference to prevent galling while allowing the coupling members to maintain their high pressure resistance. The bore liner absorbs the galling damage on its sacrificial surface rather than on the sealing surfaces of the coupling members.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the female coupling member bore is made from hard material to prevent deformation under pressure, then structural strength is improved, but galling during repeated engagement and disengagement worsens

Engineering Contradiction:

Improvestructural strength of female memberVSAvoidsealing surface integrity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The female coupling member is segmented into two functional parts: the outer structural body made from hard material for pressure resistance, and the inner bore liner made from softer material for preventing galling. This segmentation allows each component to perform its specialized function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bore liner is designed as a sacrificial, replaceable component that can wear or gall during engagement cycles. When the bore liner becomes damaged, it can be replaced without replacing the entire female coupling member, making it a cost-effective solution for protecting the expensive, high-strength coupling member.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If sealing surfaces are made from hard material to maintain seal integrity under high pressure, then sealing reliability is improved, but susceptibility to galling during misalignment worsens

Engineering Contradiction:

Improveseal integrityVSAvoidgalling during misalignment

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Different material properties are applied to different locations: the coupling members maintain hard sealing surfaces for pressure integrity, while the bore liner provides a softer, more forgiving surface that accommodates misalignment without galling. The bore liner's inner surface specifically protects the sealing interface during engagement and disengagement.

Inventive Principle:

Principle #3Local quality

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 bore liner reduces galling and maintains a fluid-tight seal by providing a durable, low-friction interface between the male and female coupling members, even under high pressure and repeated use conditions, thereby preventing leakage and extending the lifespan of the coupling components.

Implementation Method 1

providing a durable, low-friction interface between the male and female coupling members

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

radial seals that extend radially inwardly from the bore liner and seal between the male and female coupling members

Methodology Applied

Scientific EffectSealing:

Data Source

PatentUS7575256B2Bore liner for undersea hydraulic coupling

Publication Date: 2009.08.18 NAT COUPLING

AI summary

An undersea hydraulic coupling member having a bore liner that protects the coupling members from galling during assembly or disassembly. The bore liner is removable from the bore of a female undersea hydraulic coupling member. The bore liner may be integral with a seal section that may seal with a male undersea hydraulic coupling member. The bore liner also may have an outer diameter configured to engage and interlock with the bore in which the bore liner is positioned.