Semiconductor Strain Gage Ceramic Interface High Temperature
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Solution Overview
Problem
Traditional strain gages are limited in measuring strain at high temperatures, particularly above 400° F., due to mechanical bandwidth constraints and sensitivity issues, which hampers accurate monitoring of critical components in power generation facilities exposed to severe thermal strains.
Innovation Solution
A semiconductor strain gage encapsulated in a ceramic interface is attached to a metal body, allowing for high-temperature strain measurement up to 1200° F., with a porous metal/ceramic layer providing mechanical and chemical bonding, and capacitive discharge welding enabling field-deployable attachment without pre-heat or post-heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional strain gages are used for high-temperature measurement, then the device can be attached to surfaces, but the measurement capability is limited above 400° F. due to adhesive degradation and mechanical bandwidth constraints
Solution Approach 1:
The patent changes the mounting method from adhesive bonding to direct welding, and transitions from traditional foil gages to semiconductor strain gages. This parameter change enables the strain gage to withstand temperatures above 1000° F. while maintaining measurement reliability, as the welding connection and semiconductor material are thermally stable at these temperatures
Solution Approach 2:
The patent employs a composite structure combining semiconductor strain gage material with a ceramic coating layer. The ceramic coating provides thermal protection and environmental stability, allowing the semiconductor gage to operate reliably at high temperatures up to 1200° F. without degradation
2Measurement precision
If traditional foil strain gages are used, then the device structure is simple, but the sensitivity is low resulting in late detection of strain events
Solution Approach 1:
The patent replaces traditional mechanical foil strain gages with semiconductor strain gages that utilize the piezoresistive effect. This substitution dramatically increases sensitivity because semiconductor materials exhibit much higher gauge factors (20-100 times greater than foil gages), enabling early detection of strain events while accepting increased device complexity
3Ease of manufacture
If plastic adhesives are used for mounting strain gages, then the attachment process is simple, but the gage cannot survive temperatures above 400° F.
Solution Approach 1:
The patent fundamentally changes the mounting method from chemical adhesive bonding to thermal welding. This parameter change eliminates the temperature limitation of plastic adhesives, enabling the strain gage to operate at temperatures above 1000° F. while maintaining a relatively simple welding-based attachment process
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 semiconductor strain gage provides high bandwidth and sensitivity for accurate static and dynamic strain measurement at extreme temperatures, enabling effective monitoring of high-temperature components in power generation facilities without structural damage or sensitivity limitations.
Implementation Method 1
semiconductor strain gage
Implementation Method 2
capacitive discharge welding
Data Source
AI summary
The invention relates to a strain gage and methods for making and using the same to measure strain of a surface of interest. In particular, the invention relates to a semiconductor strain gage held by a metal body using a ceramic interface between the gage and the body, which that can be attached to a surface of interest. The invention also relates to methods for making the ceramic interface and attaching the semiconductor strain gage to a surface of interest. The invention, including its various embodiments, also relates to using the semiconductor strain gage to measure strain at temperatures above 1000° F.