Capacitive Pressure Sensor Using Conductive Elastomer Membrane
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Solution Overview
Problem
Existing pressure sensors for low-pressure applications are cost-intensive due to the use of magnets and Hall sensors, and are susceptible to external influences that can falsify the measuring signal.
Innovation Solution
A pressure measuring device with a membrane comprising an electrically conductive, elastomeric layer that changes capacitance in response to fluid pressure, eliminating the need for magnets and Hall sensors and integrating the signal provider directly into the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet and Hall sensor are used as the signal generator, then the measurement signal can be generated, but the measuring device becomes cost-intensive
Solution Approach 1:
The patent extracts and eliminates the expensive magnet and Hall sensor components from the measuring device. Instead, it uses a purely capacitive measurement system where the membrane itself serves as one electrode, and a separate electrode is positioned on the opposite side of the housing, removing the need for costly magnetic components while maintaining measurement functionality.
Solution Approach 2:
The patent replaces expensive, sensitive magnetic components with inexpensive capacitive elements. The capacitive sensor system uses simple conductive electrodes and dielectric layers that are much cheaper to manufacture than magnets and Hall sensors, making the device suitable for cost-sensitive applications.
2Measurement precision
If a magnet and Hall sensor are used as the signal generator, then the measurement signal can be generated, but the device complexity increases
Solution Approach 1:
The patent removes the complex magnet-Hall sensor subsystem and replaces it with a simple capacitive sensing system. The membrane structure itself becomes part of the sensing mechanism, eliminating the need for separate magnetic components and reducing overall device complexity.
Solution Approach 2:
The membrane serves multiple functions: it acts as both the pressure-sensing element and one electrode of the capacitive sensor. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure while maintaining measurement capability.
3Measurement precision
If external influences act on the measuring device, then the measurement signal can be generated, but the measurement signal becomes distorted
Solution Approach 1:
The patent addresses the vulnerability to external influences by using a capacitive measurement system that is inherently less sensitive to magnetic and electrical interference compared to Hall sensor systems. The capacitive principle converts potential interference issues into a more robust measurement approach that is insensitive to many external factors.
Solution Approach 2:
The patent replaces the magnetic field-based Hall sensor system with an electrical field-based capacitive system. This substitution changes the fundamental measurement principle from magnetic to electrical field interaction, making the device less susceptible to magnetic external influences while maintaining measurement accuracy.
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 cost-effective, robust pressure sensor that is less affected by external influences and provides a high-quality measuring signal, making it suitable for cost-sensitive applications.
Implementation Method 1
the membrane comprises an electrically conductive, elastomeric layer, wherein the action of the fluid on the membrane causes a change in the electrical capacitance of the membrane
Data Source
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AI summary
The invention relates to a measuring device (1) for measuring a measurement variable of a fluid, in particular a sensor, such as a pressure sensor, a relative pressure sensor, a differential pressure sensor, a travel sensor or the like, having a housing (2). An elastic diaphragm (8) is arranged in and/or on the housing (2). A signal transducer interacts with the diaphragm (8) such that the action of the fluid on the diaphragm (8) effects a measurement signal, corresponding to the measurement variable, at the signal transducer. The diaphragm (8) comprises an electrically conductive elastomer layer. The action of the fluid on the diaphragm (8) effects a change in the electrical capacitance of the diaphragm (8). The diaphragm (8) is operable as a signal transducer by virtue of the change in capacitance of the diaphragm (8) being provided as a measurement signal.