Optical Transducer Feedthrough Assembly Sealing
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Solution Overview
Problem
Existing feedthrough assemblies for optical sensors face challenges in high pressure and temperature environments due to the susceptibility of glass fibers to damage and the potential for leaks when using epoxy or other bonding materials.
Innovation Solution
A feedthrough assembly with a primary seal formed by a frustoconical glass plug and a secondary seal using a stack of materials, which provides redundancy and ensures sealing even under extreme conditions, reducing stress concentrations and eliminating the need for epoxy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy or bonding materials are used to seal the optical fiber in the feedthrough bore, then sealing is achieved, but the seal may crack when exposed to extreme temperatures and pressures
Solution Approach 1:
The patent removes epoxy and bonding materials from the sealing system entirely. Instead, it uses a mechanical sealing approach where the optical fiber itself forms the seal through a frustoconical geometry that creates a wedge-shaped seal against the feedthrough bore wall, eliminating the weak bonding materials that crack under extreme conditions
Solution Approach 2:
The patent introduces a frustoconical sealing surface on the optical fiber as an intermediary element between the fiber and the feedthrough bore wall. This geometric feature acts as a mediator that distributes stress and creates a reliable mechanical seal without requiring bonding materials
2Object-affected harmful factors
If the optical fiber is sealed using epoxy in the feedthrough bore, then the instrumentation portion is isolated from harsh environments, but leaks may occur when the epoxy cracks under extreme conditions
Solution Approach 1:
The patent extracts and eliminates epoxy bonding materials from the sealing system. The protection from harsh environments is achieved through a mechanical seal formed by the frustoconical optical fiber geometry pressing against the feedthrough bore wall, which does not crack like epoxy under extreme temperatures and pressures
Solution Approach 2:
The patent creates a composite sealing structure where the optical fiber (glass material) works in conjunction with the feedthrough housing (metal or other material) through a mechanical interface. This composite approach provides reliable sealing without relying on organic bonding materials that degrade in harsh environments
3Device complexity
If a single seal is used in the feedthrough assembly, then the structure is simpler, but redundancy is lacking and seal failure can occur under extreme pressure and temperature
Solution Approach 1:
The patent segments the sealing function into multiple independent sealing interfaces: (1) the frustoconical seal between the optical fiber and feedthrough bore wall, and (2) the seal at the measurement interface. This segmentation provides redundancy so that if one seal is compromised, the other maintains isolation from harsh environments
Solution Approach 2:
The patent designs the frustoconical seal geometry to distribute and cushion extreme pressures and thermal stresses across a tapered surface area rather than a single point. This beforehand cushioning design prevents stress concentration that could lead to seal failure under extreme conditions
Data Source
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AI summary
An optical transducer is provided. A "measuring" portion of the transducer may be exposed to a high pressure and fluids when the optical transducer is deployed (e.g., in a wellbore or other industrial setting). The transducer may include an optical waveguide with a first portion that forms a first seal that isolates an "instrumentation" portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. The transducer may also include a second seal with a "stack" of material elements that contact a second portion of the optical waveguide to also isolate the instrumentation portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed.