Footed Pressure Sensor with Gas-Filled Sealed Enclosures
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Solution Overview
Problem
Existing electro-mechanical pressure sensors in aeronautics are cumbersome, expensive, and sensitive to thermal variations due to the use of oil-filled conduits, which are costly, prone to freezing, and generate electric drifts when impure, making them inaccurate and costly to produce.
Innovation Solution
A pressure measuring device with sealed enclosures containing fluid, eliminating the need for transfer oil, using capacitive sensors to measure membrane deformation, and integrating a processing unit for compactness and reduced temperature sensitivity, along with a parylene coating for environmental protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oil-filled conduits are used to transmit pressure to silicon membranes, then pressure measurement is enabled, but the device becomes heavy, expensive, and sensitive to thermal variations
Solution Approach 1:
The patent removes the oil-filled conduit from the pressure sensing system entirely. Instead, it uses a sealed enclosure filled with gas (preferably air) that directly contacts the silicon membrane, eliminating the need for transfer oil and associated sealing elements, thereby reducing weight and complexity while maintaining pressure measurement capability
Solution Approach 2:
The patent introduces a gas-filled sealed enclosure as an intermediary between the pressure source and the silicon membrane. This gas medium (preferably air) transmits pressure to the membrane without requiring complex sealing and filling operations, solving the weight and complexity issues associated with oil-filled conduits
2Measurement precision
If oil-filled conduits are used to transmit pressure, then pressure transmission is achieved, but the device becomes expensive due to costly oils and extreme filling precautions
Solution Approach 1:
The patent extracts the oil-filled conduit system and replaces it with a simple sealed enclosure filled with gas. This eliminates the need for expensive silicone oil and the costly, complex filling and sealing operations required for oil-filled systems, dramatically reducing manufacturing cost while maintaining accurate pressure transmission
Solution Approach 2:
The patent uses inexpensive gas (preferably air) instead of expensive silicone oil as the pressure transmission medium. The sealed enclosure can be filled and sealed using simple, cost-effective methods, making the overall device much cheaper to manufacture while maintaining sufficient performance
3Measurement precision
If transfer fluid and conduit are used, then pressure transmission is enabled, but thermal sensitivity increases causing measurement mistakes
Solution Approach 1:
The patent changes the physical state of the pressure transmission medium from liquid (silicone oil) to gas (preferably air). This parameter change fundamentally reduces thermal sensitivity because gases have much lower viscosity and thermal mass than liquids, resulting in minimal thermal expansion and contraction that would otherwise cause measurement errors
4Measurement precision
If piezoelectric strain gages are used on silicon membranes, then pressure can be measured electrically, but the device becomes sensitive to electrochemical attacks requiring protective conduits
Solution Approach 1:
The patent removes the oil-filled protective conduit that was previously needed to shield silicon membranes from electrochemical attacks. By using a gas-filled sealed enclosure instead, the silicon membrane is exposed to a chemically inert environment (gas does not undergo electrochemical reactions with silicon), eliminating the need for protective conduits while maintaining measurement reliability
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 results in a lighter, less expensive device with improved linearity and accuracy, reduced thermal sensitivity, and simplified calibration, enabling effective pressure measurement without the need for an outer conduit, thus addressing the cost and thermal sensitivity issues of traditional sensors.
Implementation Method 1
a first deformable membrane and a second deformable membrane respectively extend... means for measuring the deformation of the first and the second deformable membranes
Implementation Method 2
The deformation of the first and the second membranes can then be measured by measuring the capacity of the thus obtained variable capacitors
Data Source
AI summary
A pressure measuring device comprising a bracket supporting a pressure sensor which defines a first sealed enclosure with a first face of the bracket, with the pressure measuring device comprising a substrate having opposite faces, opposite which a first deformable membrane and a second deformable membrane respectively extend, with the first membrane and the second membrane respectively defining with the substrate a second sealed enclosure and a third sealed membrane, with the pressure sensor comprising a cover in order to define a fourth sealed enclosure connected through a second channel to the first enclosure, with the pressure sensor comprising means for measuring the deformation of the first and the second deformable membranes.