Fire-Resistant Electrical Feedthrough With Redundant Pressure Barriers
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Solution Overview
Problem
Existing electrical penetrators for subsea applications face challenges in maintaining seal integrity and electrical continuity under high pressure and temperature conditions, particularly in environments exposed to hydrocarbon fires, due to differential thermal expansion and material stress.
Innovation Solution
A fire-resistant electrical feedthrough assembly with two bulkhead penetrator sealing elements, featuring a ceramic insulator with metalized surfaces and a two-piece metallic conductor sealed by metallic end sleeves, along with a modular design allowing for onshore assembly and testing, including a dry-mate connector for quick disconnection and convective cooling for additional thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional penetrator assemblies use O-rings or seals to seal against the penetrator housing, then sealing is achieved, but seal integrity fails under high differential pressure and high temperature conditions
Solution Approach 1:
The patent changes the sealing mechanism from elastic deformation (O-rings) to mechanical interference fit. The tapered sealing surface creates a line contact that maintains sealing under high pressure and temperature by relying on the mechanical interlock and friction between the tapered surfaces, rather than elastic recovery.
Solution Approach 2:
The patent replaces the elastomeric seal system with a metal-to-metal tapered sealing interface. This substitution eliminates the temperature limitations of O-rings and provides a sealing mechanism that relies on mechanical friction and normal force generated by the tapered geometry, suitable for high-temperature fire-resistant applications.
2Temperature
If ceramic penetrators are used, then electrical insulation and high temperature resistance are improved, but differential thermal expansion between materials induces stress and leads to failure
Solution Approach 1:
The patent uses all-metal construction for the penetrator components (conductor, housing, sealing surfaces) rather than combining ceramic with metal. This homogeneity of material type eliminates the differential thermal expansion problem between dissimilar materials while maintaining electrical insulation through proper design of the conductor-housing interface.
Solution Approach 2:
The patent creates a composite metal assembly where the conductor and housing are both metallic but with different properties. The conductor is surrounded by insulation material and positioned within the metal housing, creating a composite structure that maintains electrical isolation while allowing thermal expansion compatibility between the metal components.
3Reliability
If a one-piece conductor extends through the insulating sleeve, then electrical continuity is achieved, but maintaining electrical continuity and pressure barrier under extreme conditions becomes difficult
Solution Approach 1:
The patent segments the penetrator into distinct functional components: a conductor element, an insulating material layer, and a metal housing with tapered sealing surfaces. This segmentation allows each component to be optimized for its specific function while working together to maintain electrical continuity and pressure barrier under extreme conditions.
Solution Approach 2:
The patent adds the dimensional aspect of the tapered sealing surface, transitioning from a simple cylindrical penetrator to one with conical geometry. This dimensional change creates a line contact sealing interface that generates normal force and friction to maintain both pressure barrier and electrical continuity under thermal and pressure stress.
4Ease of manufacture
If modular design with onshore assembly is implemented, then operational costs are reduced and safety improved, but device complexity increases
Solution Approach 1:
The patent designs the penetrator as a modular assembly of discrete components (conductor, insulation, housing, sealing surfaces) that can be manufactured separately and assembled onshore. This segmentation enables factory testing and quality control before deployment, reducing offshore work and operational costs despite the increased assembly complexity.
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 provides reliable pressure containment and electrical continuity in extreme conditions, including high temperatures and pressures, while minimizing the need for offshore work and reducing operational costs through modular assembly and testing.
Implementation Method 1
The friction between the tapered sealing surfaces helps maintain seal integrity under high differential pressure
Implementation Method 2
The normal force generated by the tapered geometry presses the sealing surfaces together to prevent leakage
Implementation Method 3
convective cooling for additional thermal resistance
Data Source
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AI summary
The present invention provides a fire-resistant electrical feedthrough system for use in offshore and top-side electrical submersible pump ("ESP") installations. The fire-resistant electrical feedthrough system includes a minimum of two, redundant pressure barriers, in order to provide for safe operation and increased system reliability. The primary barrier is typically embedded within the wellhead equipment structure, while the secondary barrier is typically externally mounted.