Cryogenic Pressure Relief Valve With Insulated Thermal Path
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Solution Overview
Problem
The challenge of safely and efficiently storing liquid hydrogen fuel on aircraft is compounded by the need to minimize heat exchange with the environment, prevent cavitation, and use hydrogen-compatible materials that maintain mechanical properties under cryogenic conditions.
Innovation Solution
A pressure relief valve for cryogenic vessels is designed with valve walls that define a fluid flow passageway and a thermal conductive path, where at least a portion of this path includes a thermally insulative material like PEEK, reducing heat transfer and maintaining low temperatures within the vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a pressure relief valve is installed in a cryogenic vessel to release pressure, then pressure control is improved, but heat transfer from the surrounding environment to the cryogenic interior increases
Solution Approach 1:
The patent applies local quality by using different materials with different thermal properties in different parts of the pressure relief valve. The valve body uses a thermally insulative material (such as PEEK or other plastics) for portions that form the thermal conductive path, while metallic materials (such as Inconel) are used for components requiring mechanical strength and hydrogen compatibility. This localized material selection reduces overall heat transfer while maintaining pressure relief functionality.
Solution Approach 2:
The patent employs composite materials by combining thermally insulative non-metallic materials with hydrogen-compatible metallic materials in a single pressure relief valve assembly. The valve walls are formed from composite structures where thermoplastic materials provide thermal insulation and the metallic components (filter, spool, mechanical interfaces) provide structural integrity and hydrogen compatibility. This composite approach resolves the contradiction between pressure control and heat transfer reduction.
2Strength
If metallic materials are used for the pressure relief valve components, then mechanical strength and hydrogen compatibility are improved, but thermal conductivity increases leading to heat transfer
Solution Approach 1:
The patent applies local quality by strategically placing metallic materials only where mechanical strength is critical (spool, filter, mechanical interfaces) while using thermally insulative non-metallic materials for the valve walls and other portions forming the thermal conductive path. This localized material distribution minimizes heat transfer while maintaining necessary mechanical properties.
Solution Approach 2:
The patent uses composite materials by integrating thermally insulative materials (PEEK, plastics) with hydrogen-compatible metallic materials (Inconel) in a unified pressure relief valve structure. The composite construction allows different sections to have optimized thermal and mechanical properties, reducing overall heat transfer while maintaining structural integrity and hydrogen compatibility.
3Reliability
If a separate seal component is added to ensure sealing between valve walls and spool, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies merging by integrating the sealing function directly into the valve walls through their material properties. The thermally insulative valve walls are designed to work with the spool material (Inconel or other metallic materials) to create a seal through material compliance and surface contact, eliminating the need for a separate seal component. This merging of functions reduces device complexity while maintaining sealing reliability.
Solution Approach 2:
The patent employs self-service by allowing the valve walls and spool materials to self-seal through their inherent material properties. The combination of thermally insulative valve wall material and metallic spool material creates a seal automatically through contact pressure and material compliance, without requiring external seal components. This self-sealing mechanism simplifies the device structure.
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 use of a thermally insulative portion in the pressure relief valve effectively reduces heat transfer between the cryogenic vessel and the surrounding environment, helping to maintain the low temperature and secure storage of hydrogen fuel.
Implementation Method 1
at least a portion of the thermal conductive path comprises a thermally insulative portion
Data Source
AI summary
A pressure relief valve for a cryogenic vessel. The pressure relief valve includes valve walls defining a fluid flow passageway through the pressure relief valve. The valve walls define a thermal conductive path between an interior of the cryogenic vessel and a surrounding environment. At least a portion of the thermal conductive path comprises a thermally insulative portion.