Electric Feedthrough Assembly Using Inconel and Ceramic for Harsh Environments
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Solution Overview
Problem
Existing electric feedthroughs fail in high temperature, high pressure, and corrosive environments, such as those found in ammonia cracking systems, due to susceptibility to thermal stress, mechanical stress, and chemical attack from gases like heated ammonia, leading to damage and failure.
Innovation Solution
The electric feedthrough assembly employs a pass-thru stud with nickel alloy washers and ceramic washers, along with an insulating sleeve and a body with internal threading, designed to couple with a pressure vessel fitting, utilizing materials like Inconel for enhanced temperature and corrosion resistance, and silver washers for sealing, to maintain electrical conductivity and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known electric feedthroughs are used in high temperature environments, then electrical conductivity is maintained, but reliability deteriorates due to thermal stress and component failure above 600°C
Solution Approach 1:
The feedthrough assembly uses a composite structure combining Inconel® alloy (nickel-chromium-iron) for the stud and nuts, ceramic materials for insulation, and silver washers for sealing. This composite material approach allows the assembly to withstand temperatures exceeding 600°C while maintaining electrical conductivity through the Inconel® stud and providing thermal insulation through the ceramic components, thereby resolving the contradiction between reliability and high temperature operation.
Solution Approach 2:
The invention changes the material parameters of the feedthrough components, specifically using Inconel® alloy which has superior high-temperature strength and oxidation resistance compared to conventional materials. The silver washers provide high-temperature sealing capability. These parameter changes in material selection enable the feedthrough to operate reliably at temperatures above 600°C where conventional feedthroughs fail.
2Reliability
If known electric feedthroughs are used in corrosive environments, then electrical conductivity is maintained, but reliability deteriorates due to chemical attack from heated ammonia and hydrogen
Solution Approach 1:
The feedthrough assembly employs Inconel® alloy which contains chromium and iron, providing excellent resistance to corrosion from heated ammonia and hydrogen. The ceramic insulating material also provides chemical inertness. This composite material selection directly addresses the corrosive environment challenge, allowing the feedthrough to maintain reliability in chemically aggressive conditions where conventional materials would deteriorate.
3Reliability
If known electric feedthroughs are used in high pressure environments, then electrical conductivity is maintained, but reliability deteriorates due to mechanical stress and sealing failure
Solution Approach 1:
The Inconel® alloy stud and nuts provide high mechanical strength and stress resistance, while the silver washers provide effective sealing under pressure. The ceramic insulator maintains structural integrity under mechanical stress. This composite construction enables the feedthrough to operate reliably in high-pressure environments by distributing and withstanding mechanical loads that would cause failure in conventional single-material designs.
4Reliability
If multiple materials with different thermal expansion coefficients are used in electric feedthroughs, then electrical conductivity and insulation are provided, but reliability deteriorates due to thermal stress from differential expansion
Solution Approach 1:
The invention selects Inconel® alloy which has thermal expansion properties that are more compatible with ceramic materials compared to conventional stainless steel or aluminum. The silver washers also have favorable thermal expansion characteristics. By changing the material parameters to match thermal expansion coefficients more closely, the differential thermal stress is reduced, preventing seal failure and maintaining reliability during thermal cycling.
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 electrical conductivity and mechanical stability in extreme conditions, preventing damage from thermal expansion, mechanical stress, and corrosive environments, ensuring the electric feedthrough assembly's longevity and performance in high-temperature, high-pressure, and corrosive settings.
Implementation Method 1
when known electric feedthroughs are exposed to high temperatures which are significantly higher than those at which its components were assembled, these components expand by different amounts due to differences in coefficient of thermal expansion
Implementation Method 2
The insulating material can in turn be surrounded by a metal sleeve
Implementation Method 3
The insulating material can in turn be surrounded by a metal sleeve, which through a variety of known techniques, can be connected to the housing of the catalyst unit
Implementation Method 4
Heated ammonia is known to be especially corrosive, and is characterized by its ability to attack and damage many materials, including steel, stainless steel, copper, brass, aluminum, rubbers, and plastics
Data Source
AI summary
The present invention relates, in general, to an apparatus for an electrical power feedthrough suitable for use in high temperature, high pressure, and/or corrosive environments, such as, for example, within ammonia cracking (i.e., dissociation) systems. The present invention is fabricated from conductive nickel alloys which have high melting temperatures, and which are resistant to corrosion at high temperatures, as well as non-conductive ceramic materials which provide electrical insulation between the systems that feedthrough is coupled to.