SiC Diaphragm Pressure Sensor for High-Temperature Interference
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Solution Overview
Problem
Fibre optical systems for pressure measurement face limitations in reliability and accuracy, especially in high-temperature environments, where existing materials and designs fail to provide stable and precise measurements of static and dynamic pressures.
Innovation Solution
The system employs a pressure sensor element made of SiC with a diaphragm and optical fibre components capable of withstanding temperatures up to 800°C, utilizing a MEMS device with a monocrystalline SiC structure and a fluorescent member for enhanced accuracy and temperature measurement, allowing for reliable pressure determination in harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used for the pressure sensor element and optical fibre, then the system can be manufactured with standard materials and processes, but the system fails to provide reliable measurements in high-temperature environments above 800°C
Solution Approach 1:
The patent changes the material parameter of the pressure sensor element and optical fibre from conventional materials to SiC (silicon carbide), which has fundamentally different thermal stability properties. SiC maintains its structural integrity and mechanical properties at temperatures up to 1500°C, enabling the system to operate reliably in high-temperature environments where conventional materials would fail.
Solution Approach 2:
The patent employs SiC, a composite material with exceptional high-temperature stability and mechanical strength. SiC combines the advantages of ceramics (heat resistance) and materials with high Young's modulus (mechanical strength), creating a sensor element that can withstand both thermal and mechanical stresses in harsh environments.
2Temperature
If a diaphragm with high temperature stability is used, then the system can operate in high-temperature environments, but the measurement precision of dynamic pressures may be reduced due to material property changes
Solution Approach 1:
The patent selects SiC as the diaphragm material, which has a fundamentally different combination of thermal and mechanical properties compared to conventional materials. SiC maintains its Young's modulus and structural integrity across a wide temperature range, ensuring that the diaphragm's mechanical response to pressure remains predictable and precise even at high temperatures.
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
This configuration enables high-accuracy pressure measurements in extreme temperatures, including those found in fuel combustion processes, by maintaining the distance between sensor surfaces independently of temperature and allowing for dynamic pressure measurement with high frequency resolution.
Implementation Method 1
said surfaces are arranged so as to cause interference phenomena of light inciding substantially perpendicularly onto and reflected by the two surfaces depending upon the actual distance between these surfaces
Implementation Method 2
a fluorescent member arranged in the path of said light transmitted from said light source up-stream said reflecting surfaces of the pressure sensor element and configured to absorb a portion of said light for resending secondary light resulting from optical excitation in the opposite direction in said optical fibre
Data Source
AI summary
A fiber optical system for pressure measurement has a pressure sensor element (4) with at least two parallel partially reflecting surfaces (5, 7), one of which is arranged on a diaphragm (6) movable with respect to another fixed said surface as a consequence of pressure differences across said diaphragm. Said surfaces are arranged so as to cause interference phenomena of light inciding substantially perpendicularly onto and reflected by the two surfaces depending upon the actual 10 distance between these surfaces. The pressure sensor element is made of material being stable at a continuous temperature up to at least 800° C. At least said diaphragm (6) of the sensor element is made of Si C, and at least a part (23) of the optical fiber (3) connecting to said sensor element is made of a material able to withstand a continuous temperature of at least 800° C.