Feed Through Seals With Undercut Regions For Thermal Cycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The difference in Coefficient of Thermal Expansion (CTE) between flexible sealant materials and metal or composite materials used in feed-through fittings leads to the sealant pulling away from the fitting body during thermal excursions, causing unintended leakage.
Innovation Solution
A fitting assembly with a solid outer body and a pass-through bore featuring undercut regions, where a liquid-phase filler material with a high CTE is introduced and solidified to occupy the pass-through bore and undercut areas, providing a flexible seal that maintains hermeticity across temperature and pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible sealant materials with high CTE are used in feed-through fittings, then the sealant can provide effective sealing, but the sealant pulls away from the fitting body during thermal excursions causing leakage
Solution Approach 1:
The patent changes the geometric parameters of the bore by introducing undercut regions that create expansion and contraction bearing surfaces at different radial positions. This geometric modification allows the sealant to maintain contact with the fitting body during thermal expansion and contraction cycles, resolving the adhesion stability issue while preserving sealing effectiveness
Solution Approach 2:
The patent transitions from a simple cylindrical bore to a bore with undercut regions that create radial dimension variations. The expansion bearing surface is positioned radially outward from the contraction bearing surface, creating a multi-level radial structure that accommodates thermal dimensionality changes in the sealant material
2Ease of manufacture
If traditional cylindrical bores are used in feed-through fittings, then manufacturing is simple, but sealant pulls away during thermal excursions
Solution Approach 1:
The patent modifies the bore geometry by introducing undercut regions with specific radial positioning of expansion and contraction bearing surfaces. This geometric parameter change maintains manufacturability through standard machining processes while fundamentally improving seal integrity during thermal cycling
3Ease of manufacture
If high-CTE polymer sealants are used, then lower-cost materials can be employed, but unintended ingress or egress occurs through the fitting body
Solution Approach 1:
The patent modifies the bore geometry to include undercut regions with expansion and contraction bearing surfaces positioned at different radial locations. This allows inexpensive high-CTE polymer sealants to maintain hermetic sealing by preventing pull-away during thermal excursions, thus achieving both cost reduction and reliability
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 solution effectively maintains a hermetic seal over a wide temperature range and pressure differential, improving the durability and integrity of feed-through fittings while allowing the use of lower-cost, high-CTE polymer sealants.
Implementation Method 1
The liquid-phase filler material is solidified to form a flexible filler material substantially occupying a volume of the pass-through bore and the undercut region
Implementation Method 2
The CTE (Coefficient of Thermal Expansion) of flexible sealant materials (primarily polymers) is universally much greater than the CTE of metal or composite materials used to construct feed-through fitting bodies
Data Source
AI summary
An embodiment of a fitting assembly includes a fitting having at least a solid outer body, a pass-through bore, and at least one undercut region. The pass-through bore is defined by at least one pass-through bore wall, extending longitudinally through a length of the outer body from a first end to a second end. The at least one undercut region is formed into the at least one pass-through bore wall, and includes at least one expansion bearing surface disposed radially outward of at least one contraction bearing surface.