Hermetically Sealed Fiber Sensing Cable Package
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Solution Overview
Problem
Conventional fiber optic sensors face challenges in harsh environments due to high temperatures, corrosive agents, and electromagnetic interference, limiting their effectiveness in applications like turbine engines and coal gasifiers, where reliable and durable temperature sensing solutions are needed.
Innovation Solution
A hermetically sealed fiber sensing cable package with a thermally conductive enclosure and reflective material, featuring high-melting-point materials and fiber Bragg grating sensors, designed to withstand extreme temperatures and maintain mechanical strength, while reflecting thermal radiation and convection effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal coating materials are used to protect fiber sensors in harsh environments, then mechanical strength is improved, but thermal expansion mismatch causes interfacial stress and strain that degrades sensor performance above 1000° F.
Solution Approach 1:
The patent employs a multi-layer composite coating structure consisting of inner and outer metal layers with different thermal expansion coefficients. The inner layer (e.g., Ni, TiNi) provides strong adhesion to the fiber and accommodates thermal expansion at lower temperatures, while the outer layer (e.g., Al, Au) provides oxidation resistance and mechanical protection at high temperatures. This composite structure resolves the thermal expansion mismatch problem by distributing thermal stress across multiple materials with complementary properties.
2Ease of manufacture
If polymer-based packaging materials are used for fiber temperature sensors, then ease of manufacture is improved, but reliability deteriorates in high-temperature environments above 1000° F.
Solution Approach 1:
The patent transitions from polymer-based packaging to metal-based packaging materials that can withstand high temperatures. The metal packaging structure undergoes parameter changes in terms of material composition, thermal stability, and mechanical properties to maintain reliability in environments above 1000° F. while still allowing for practical manufacturing through techniques like laser welding and precision drawing.
3Device complexity
If fiber sensors are deployed in harsh environments without protective packaging, then device complexity is reduced, but the sensors experience detrimental effects from high temperature, pressure, and corrosion
Solution Approach 1:
The patent implements a nested protective structure where the fiber sensor is first coated with metal layers, then embedded in a metal tube or capillary, and finally sealed within an outer protective housing. This multi-level nesting provides progressive protection against thermal, mechanical, and corrosive hazards while maintaining a relatively compact and integrated design that doesn't excessively increase device complexity.
4Measurement precision
If conventional sensors are used in harsh environments, then measurement capability is achieved, but the sensors have short lifetime due to high temperature, pressure, and corrosion
Solution Approach 1:
The patent creates a protected environment for the fiber sensor by sealing it within a hermetically sealed metal package that excludes corrosive gases and moisture. The metal packaging acts as a barrier that maintains an inert environment around the sensitive fiber optic components, preventing chemical degradation and extending sensor lifetime in harsh industrial environments while preserving temperature measurement capability.
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 enables reliable, long-term temperature profile mapping in harsh environments, with the cable package surviving thermal blasts and maintaining mechanical integrity, effectively addressing the limitations of existing sensors in high-temperature, high-pressure, and corrosive conditions.
Implementation Method 1
a thermally conductive enclosure comprising a reflective material with a melting point greater than 2000° F. ( ̃1093° C.), wherein the material reflects at least 50 percent of incident radiation at wavelengths less than 2 microns
Implementation Method 2
The fiber and fiber sensors are sealed inside the capillary or tube for protection
Implementation Method 3
a thermally conductive enclosure
Data Source
AI summary
A gasification distributed temperature sensing system is disclosed. The sensing system includes a gasification vessel and a harsh environment fiber sensing cable package disposed within the gasification vessel, the sensing cable package includes a thermally conductive enclosure and at least one sensor cable including a distributed array of high-temperature fiber Bragg grating sensors, wherein the sensors are disposed and hermetically sealed within the thermally conductive enclosure.