Double-Wall Bellows Conduit for Cryogenic Leak Detection

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Solution Overview

Problem

Flexible conduits in cryogenic propulsion systems are susceptible to manufacturing variances and incidental damage, which can lead to potential failure of pressurized-propellant feed lines, potentially damaging the main propulsion system if not timely identified.

Innovation Solution

A conduit design featuring a bellows structure with corrugated plies and hermetically coupled collars, equipped with sensors to monitor conditions within the interstitial space, allowing for detection of leaks and accommodating displacements during operation, while enabling efficient and reliable fluid transport.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible conduit is used to accommodate displacements during operation, then adaptability is improved, but reliability deteriorates due to susceptibility to manufacturing variances and incidental damage

Engineering Contradiction:

Improveaccommodation of displacementsVSAvoidresistance to failure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The conduit is divided into multiple hermetically sealed sections (collars with sealed bellows and isolated interstitial spaces). Each section can independently accommodate displacements through its bellows structure while maintaining hermetic sealing, thus preserving reliability while providing adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Sensors are introduced as intermediary elements that monitor the interstitial space between the bellows plies. These sensors detect leaks or anomalies early, providing warning before actual failure occurs, thus maintaining reliability while allowing the flexible structure to accommodate displacements.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If hermetical coupling of collar portions is implemented, then reliability is improved, but device complexity increases due to multiple welds and assembly steps

Engineering Contradiction:

Improvehermetic sealingVSAvoidnumber of welds and assembly steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bellows structure integrates multiple functions into a single component: it provides hermetic sealing between collar portions, creates the interstitial space for sensor monitoring, and accommodates thermal expansion and displacements. This merging reduces overall device complexity while maintaining reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The corrugated bellows structure serves multiple purposes simultaneously: it acts as a hermetic seal, a displacement accommodation mechanism, and a structural element connecting collar portions. This multi-functionality reduces the need for separate components and assembly steps.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If sensors are integrated to monitor interstitial space, then reliability is improved through leak detection, but device complexity increases

Engineering Contradiction:

Improveleak detection capabilityVSAvoidsensor integration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interstitial space between the bellows plies serves as both the structural element allowing flexibility and the monitoring zone for sensors. This self-service approach uses the existing space for dual purposes, minimizing additional complexity while enabling reliable leak detection.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Sensors are strategically placed only in the interstitial spaces where leaks would first manifest, rather than throughout the entire conduit. This localized monitoring approach provides effective leak detection while minimizing the number of sensors and overall complexity.

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 conduit provides a compliant structure for cryogenic fuels, allowing for the detection of leaks and ensuring reliable operation by accommodating displacements, thus preventing damage to the propulsion system.

Implementation Method 1

a first collar that comprises a first outer collar portion, a first inner collar portion, and a first weld, hermetically coupling the first outer collar portion and the first inner collar portion

Methodology Applied

Scientific EffectWelding: Welding

Implementation Method 2

a bellows that comprises a central axis, a corrugated inboard ply, a corrugated outboard ply, and an interstitial space, located between the corrugated inboard ply and the corrugated outboard ply

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11035515B2Conduits for transporting fluids

Publication Date: 2021.06.15 THE BOEING CO

AI summary

A conduit for transporting a fluid comprises a first collar, a second collar, and a bellows. The bellows comprises a corrugated inboard ply, a corrugated outboard ply, and an interstitial space, interposed between the corrugated inboard ply and the corrugated outboard ply. The conduit additionally comprises a second weld, hermetically coupling the corrugated inboard ply and a first outer collar portion, a third weld, hermetically coupling the corrugated outboard ply and a first inner collar portion, a fourth weld, hermetically coupling the corrugated inboard ply and a second outer collar portion, a fifth weld, hermetically coupling the corrugated outboard ply and a second inner collar portion, and a first sensor, communicatively coupled with the interstitial space.