Pressure Sensor Diaphragm Isolation via Elastic Decoupling Arms
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Solution Overview
Problem
Pressure measurement devices in the aeronautical field face accuracy issues due to temperature variations causing differential expansions between materials, leading to stress and distorted measurements.
Innovation Solution
A mechanical decoupling structure with elastically deformable arms and a plate made of the same material as the membrane and frame, transforming differential thermal expansions into rotational movements that do not affect the membrane's deformation, ensuring accurate pressure measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the membrane and substrate are made of different materials to enable pressure sensing, then pressure measurement capability is achieved, but differential thermal expansion occurs causing measurement distortion
Solution Approach 1:
The device is divided into separate functional components: a pressure-sensitive membrane made of one material and a substrate made of another material, connected through elastic arms. This segmentation allows each component to be optimized for its specific function while isolating them from harmful thermal interactions.
Solution Approach 2:
Elastic arms act as intermediary elements connecting the membrane and substrate. These arms transmit mechanical deformation from pressure while isolating the membrane from thermal expansion stresses, serving as a mediator that separates the useful mechanical signal from harmful thermal effects.
2Strength
If rigid connections are used between membrane and frame for structural stability, then structural integrity is improved, but thermal stresses are transmitted to the membrane causing measurement distortion
Solution Approach 1:
Elastic arms with curved portions function as flexible connecting elements that maintain structural integrity while accommodating thermal expansion. The curved geometry provides flexibility to absorb thermal stresses without transmitting them to the membrane, unlike rigid connections would.
3Device complexity
If the membrane is directly connected to the frame for simplicity, then device complexity is reduced, but thermal expansion causes parasitic deflection of the membrane
Solution Approach 1:
The connection between membrane and frame is made dynamic through elastic arms that can deform and adapt to thermal expansion. This dynamic connection allows the structure to accommodate temperature variations without causing parasitic deflections, unlike a fixed rigid connection would.
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 effectively isolates the membrane from thermal stresses, enhancing the reliability and accuracy of pressure measurements by converting thermal forces into rotational movements that do not induce parasitic deflection, thus improving measurement precision.
Implementation Method 1
transform into resulting movement parallel to the mean plane any differential thermal expansion between the frame and the plate
Implementation Method 2
elastically deformable arms extending between the plate and the frame
Implementation Method 3
a membrane which has a surface intended to be subjected to a pressurized fluid and which is arranged to deform elastically as a function of the pressure
Implementation Method 4
The two electrodes subjected to an electric voltage therefore form a capacitor whose capacitance varies according to the pressure
Data Source
Figure 1~2
AI summary
The invention relates to a pressure detection device including a mount on which is attached a pressure sensor comprising a diaphragm which has a surface intended to be subjected to a pressurized fluid and is arranged to elastically deform according to the pressure, and means for determining the deformation of the diaphragm along an axis normal to a mid-plane of the diaphragm in the rest state. The diaphragm is supported by a frame connected to the mount by a mechanical decoupling structure to isolate the diaphragm from forces resulting from differential thermal expansion between the frame and the mount, the diaphragm and the frame being made of the same material.