Hydrogen Pipe Coupling with Spring-Loaded Inner Seal Preload

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Solution Overview

Problem

Existing hydrogen piping systems face challenges in maintaining low leak rates and ensuring reliable couplings, especially in cryogenic and multiple-wall pipe configurations, due to limitations in seal seating loads and thermal stress concentrations.

Innovation Solution

A hydrogen pipe coupling arrangement with a spring-energized flange concept that applies a pre-pressing force to inner seals using spring elements, enhancing the seating load on both inner and outer seals, and utilizing metal bellows or diaphragms to provide additional force on flanges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a pressing device is used to press the first coupling portion and the second coupling portion together, then the coupling strength is improved, but the seal seating load is insufficient leading to increased leakage rates

Engineering Contradiction:

Improvecoupling strengthVSAvoidseal performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The coupling arrangement is divided into separate inner and outer coupling portions that can be independently pressed together, allowing differential pressing forces to be applied to different seal locations. The inner coupling portion can be pressed with a different force than the outer coupling portion, enabling optimized seal seating loads for each seal type.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the pressing force parameter by introducing a differential pressing mechanism where the inner coupling portion and outer coupling portion can be pressed with different forces. This allows the seal seating load to be optimized independently for each seal, improving overall seal performance while maintaining coupling strength.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a simple single-wall pipe coupling is used, then the device complexity is reduced, but thermal insulation performance deteriorates

Engineering Contradiction:

Improvepipe structure complexityVSAvoidthermal insulation performance

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The invention uses a nested structure where an inner pipe is placed inside an outer pipe, creating a vacuum-insulated or thermally insulated double-wall pipe system. This nested configuration provides excellent thermal insulation for cryogenic hydrogen transport while maintaining a relatively compact and manageable structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The double-wall pipe structure combines different materials and spaces (inner pipe, vacuum space or insulation medium, outer pipe) to create a composite thermal insulation system. This composite structure provides superior thermal performance compared to simple single-wall pipes.

Inventive Principle:

Principle #40Composite materials

3Reliability

If high pressing force is applied to ensure seal integrity, then leakage rates are reduced, but thermal stress concentrations increase in the coupling portions

Engineering Contradiction:

Improveseal integrityVSAvoidthermal stress concentration

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

By segmenting the coupling into inner and outer coupling portions with separate pressing capabilities, the invention allows different pressing forces to be applied to different sections. This prevents excessive thermal stress concentration in any single area while maintaining adequate seal integrity through optimized localized pressing forces.

Inventive Principle:

Principle #1Segmentation

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

Improves seal performance and reduces leakage rates, ensuring safety and operational continuity by maintaining vacuum insulation and extending maintenance intervals in hydrogen distribution systems.

Implementation Method 1

at least one spring element configured to apply a pre-pressing force onto the inner seal in addition to the pressing force of the pressing device

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

A space between the inner pipe and the outer pipe can be evacuated or filled with a special gas for achieving a thermal insulation

Methodology Applied

Scientific EffectVacuum insulation: Vacuum

Implementation Method 3

transfer lines with optimal insulation is essential. For transportation of liquid hydrogen, cryogenic piping system can be used. Such cryogenic piping systems have multiple-wall pipe sections with an inner pipe and an outer pipe. Within the inner pipe, the cryogenic liquid is transported. A space between the inner pipe and the outer pipe can be evacuated or filled with a special gas for achieving a thermal insulation

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS12372185B2Hydrogen pipe coupling arrangement with enhanced inner sealing

Publication Date: 2025.07.29 AIRBUS OPERATIONS GMBH

AI summary

A coupling for a hydrogen pipe for coupling multi-wall pipe sections which is equipped with an inner seal and an outer seal and a pressing device that presses the pipe sections together. The hydrogen pipe coupling arrangement comprises at least one spring element configured to apply a pre-pressing force onto the inner seal in addition to a pressing force of the pressing device.