Cryogenic Fluid Conduit Bellows With Sensor-Monitored Interstitial Space
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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, posing a risk to the main propulsion system if not timely identified.
Innovation Solution
A conduit design featuring a bellows structure with corrugated plies and a sensor system to monitor conditions within an interstitial space, allowing for detection of leaks and accommodating displacements, while maintaining hermetic seals through strategically placed welds, and allowing for separate formation and interconnection of collar portions for efficient assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible conduit with bellows structure is used to accommodate displacements, then the adaptability and compliance are improved, but the reliability deteriorates due to susceptibility to manufacturing variances and incidental damage
Solution Approach 1:
The conduit is divided into multiple hermetically sealed sections (collars with sealed bellows) separated by sensor-equipped junctions. This segmentation isolates potential failure zones, allowing local damage to be contained and detected without compromising the entire system, thereby maintaining reliability while preserving compliance through the bellows structure.
Solution Approach 2:
Sensors are integrated at the collar junctions to provide real-time feedback on the condition of the bellows and interstitial spaces. This feedback mechanism enables early detection of manufacturing defects or incidental damage, allowing for timely intervention before failures propagate, thus resolving the reliability concern while maintaining the compliant bellows design.
2Reliability
If multiple hermetic seals are implemented through strategic welds, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The hermetic sealing is segmented into discrete weld locations at collar junctions rather than continuous sealing along the entire conduit. This approach achieves reliable hermetic sealing at critical interfaces while minimizing the total weld length and complexity, as each collar assembly can be independently sealed and tested.
Solution Approach 2:
Collar assemblies with pre-formed hermetic seals are prepared separately before final assembly. This preliminary action allows for quality control and testing of individual sealed units, ensuring reliability while reducing on-site assembly complexity. The pre-sealed collars are then connected to form the complete conduit system.
3Difficulty of detecting and measuring
If sensors are integrated to monitor interstitial space conditions, then the detection capability is improved, but the device complexity increases
Solution Approach 1:
The sensing function is extracted and concentrated at specific collar junctions rather than distributed throughout the entire conduit. Sensors monitor the interstitial spaces at these strategic locations where leaks would indicate bellows or seal failures. This approach provides effective leak detection capability while minimizing sensor quantity and system complexity compared to continuous monitoring.
Solution Approach 2:
The collar structures serve multiple functions: mechanical connection, hermetic sealing, and sensor mounting platforms. This multi-functionality reduces overall device complexity by combining several components into integrated assemblies, where the collar both seals the bellows and provides the interface for leak detection sensors.
4Ease of manufacture
If collars are formed separately and interconnected through welds, then the ease of manufacture is improved, but the device complexity increases
Solution Approach 1:
The conduit is segmented into modular collar assemblies that can be manufactured independently using standard fabrication processes. Each collar with its sealed bellows can be produced separately, quality-tested, and then interconnected through controlled welds. This segmentation dramatically improves ease of manufacture and quality control while the modular nature actually reduces overall structural complexity compared to monolithic designs.
Solution Approach 2:
Collar assemblies are pre-formed and pre-sealed before final interconnection. This preliminary action allows for optimized manufacturing of individual components using appropriate processes for each material, improving ease of manufacture. The pre-assembled collars are then connected in a simplified final assembly step, reducing on-site manufacturing complexity.
Data Source
AI summary
A conduit for transporting a fluid comprises a first collar, a second collar, and a bellows. The bellows comprises a first corrugated outboard ply, a corrugated inboard ply, an interstitial space, interposed between the corrugated inboard ply and the first corrugated outboard ply, and a second corrugated outboard ply within the interstitial space. The first corrugated outboard ply and the corrugated inboard ply are hermetically coupled to the first collar and the second collar. The conduit additionally comprises a first sensor, communicatively coupled with an interstitial space. The second corrugated outboard ply is not hermetically coupled to the first collar or the second collar.