Invar Alloy Seal Member for Extreme Temperature Fluid Fitting
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Solution Overview
Problem
Existing fluid fitting assemblies with elastomeric O-rings have a narrow working temperature range, making them unsuitable for extreme temperature conditions, and require costly and time-consuming special designs for high-performance applications.
Innovation Solution
A seal member with specific geometries, such as resembling a small case letter 'r', handsaw, compass saw, 'L', 'T', elongated 'S', and capital 'L' shapes, made from materials like stainless steel or silver-plated metals, which provides an interference fit and spring-like action to maintain sealability across extreme temperatures without the need for unique parts or special port designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an elastomeric O-ring is used as the seal member, then the assembly is simple and low cost, but the working temperature range is narrow and sealability is compromised at extreme temperatures
Solution Approach 1:
The seal member is made from Invar alloy, which has an exceptionally low coefficient of thermal expansion (approximately 1.2×10^-6 per °C), allowing it to maintain its dimensional stability and sealing capability across extreme temperature ranges from -320°F to over 1000°F. This material parameter change resolves the contradiction by enabling extreme temperature operation while maintaining seal integrity.
Solution Approach 2:
The seal member utilizes Invar alloy, a composite material consisting of iron and nickel (typically 64% Fe, 36% Ni), which combines the benefits of low thermal expansion with adequate strength and sealing properties. This composite material approach allows the seal to function reliably in extreme temperatures while maintaining structural integrity.
2Reliability
If special port designs, non-standard fittings, and unique parts are fabricated for extreme temperature applications, then sealability at extreme temperatures is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The Invar alloy seal member can be used with standard, off-the-shelf fittings and ports (such as SAE J1926 and ISO 6149 standards) while providing extreme temperature performance. This universal application capability eliminates the need for special port designs and non-standard fittings, reducing device complexity while maintaining sealability at extreme temperatures.
Solution Approach 2:
The Invar seal member provides a cost-effective solution by using a single, simple component that can be easily replaced if needed, rather than requiring expensive, complex, custom-fabricated port designs and unique parts. The simplicity of the seal member design reduces manufacturing costs while achieving the desired extreme temperature performance.
3Ease of manufacture
If standard and inexpensive parts are used in the fluid fitting assembly, then the manufacturing cost is reduced, but the ability to operate in extreme temperature environments is limited
Solution Approach 1:
By changing the material parameter of the seal member to Invar alloy with its unique low thermal expansion properties, the assembly can use standard, inexpensive fittings and ports while achieving operation in extreme temperature environments from -320°F to over 1000°F. This material parameter change enables both cost reduction and extreme temperature capability.
Solution Approach 2:
The Invar seal member provides localized extreme temperature resistance at the sealing interface, allowing the rest of the assembly to use standard, inexpensive materials. This local quality approach enables the critical sealing function to withstand extreme temperatures while the overall assembly remains cost-effective using conventional parts.
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
Enables fluid fitting assemblies to operate effectively in cryogenic and high-temperature environments without compromising sealability, using standard and inexpensive parts, thus eliminating the need for costly and time-consuming modifications.
Implementation Method 1
A seal member 200 is provided which is compatible with inexpensive and readily available (e.g., off-the-shelf) parts and which is also able to accommodate extreme working temperature conditions without any compromise in sealability. Specifically, for example, the seal member can be used in a fluid fitting assembly comprising a receiving member with an inexpensive port design (e.g., SAE J1926 and ISO 6149) and a standard fitting member.
Implementation Method 2
The seal member (i.e., an elastomeric O-ring) is squeezed into this chamber to seal the interface between the receiving member and the fitting member.
Data Source
AI summary
A fluid fitting assembly (100), suitable for use in extreme working temperature conditions, can comprise a receiving member (110) with an inexpensive port design (e.g., SAE J1926 and/or ISO 6149), a standard fitting member (112), and a metal seal member (200). The seal member (200) comprises a ring portion (212) and a shoulder portion (218/220) extending radially from a head-adjacent region of the ring portion (212). The outer radial surface of the ring portion (212) seats against the chamfer section (126) of the receiving member (110) and the head-adjacent axial surface of the shoulder portion (218/220) seats against the undercut section (136) of the fitting member (112).