Capacitive Pressure Sensor with Intermediate Circuit for High Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-temperature pressure sensors used in extrusion and injection molding processes face challenges such as signal interference from stray capacitances and thermally induced stresses, which affect accuracy and component lifespan, and often require temperature compensation, increasing complexity and potential for defects.
Innovation Solution
A high-temperature pressure sensor design with an intermediate circuit to transform AC signals to DC closer to the sensor, minimizing stray capacitances and using materials with matched thermal expansion coefficients to reduce stress, and intrinsic temperature compensation through component geometry and material selection, eliminating the need for a temperature sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-temperature pressure sensors are used in extrusion and injection molding processes, then pressure monitoring capability is achieved, but signal interference from stray capacitances and thermally induced stresses reduce measurement precision
Solution Approach 1:
An intermediate circuit is introduced between the AC capacitive pressure sensor and the DC control system. This intermediate circuit converts AC signals to DC signals and minimizes the effects of stray capacitances, thereby reducing signal interference and improving measurement precision in high-temperature environments.
Solution Approach 2:
The patent changes the signal parameter from AC to DC through the intermediate circuit. This parameter transformation reduces the impact of stray capacitances and thermally induced stresses on the pressure measurement signal, thereby improving measurement accuracy in high-temperature conditions.
2Measurement precision
If temperature compensation is added to compensate for thermal effects, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The intermediate circuit automatically performs temperature compensation functions without requiring additional temperature sensors or complex compensation mechanisms. The circuit design inherently compensates for thermal effects through its AC-to-DC conversion process and stray capacitance minimization, thereby improving measurement accuracy while maintaining simple device architecture.
3Measurement precision
If AC signal transformation to DC is performed closer to the sensor, then signal fidelity is improved, but additional circuit components are required
Solution Approach 1:
An intermediate circuit is positioned between the pressure sensor and the control system to perform AC-to-DC signal transformation. This intermediate circuit improves signal fidelity by minimizing the effects of stray capacitances and thermally induced stresses during the conversion process, while the added complexity is justified by the significant improvement in 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
This design enhances signal fidelity, reduces interference, and extends sensor lifespan by minimizing thermally induced stresses and signal losses, while allowing for accurate pressure measurement across a wide temperature range without additional temperature sensing components.
Implementation Method 1
a capacitive sensor that varies an output signal in response to a change in pressure
Implementation Method 2
an intermediate circuit to transform AC signals to DC closer to the sensor, minimizing stray capacitances
Implementation Method 3
using materials with matched thermal expansion coefficients to reduce stress
Data Source
Figure 1~2
Figure 3~3A
Figure 4
AI summary
High temperature pressure sensing devices and methods are disclosed. In some embodiments, a high temperature pressure sensor including intrinsic zero output and span correction versus temperature is disclosed. In addition, ways in which to improve high temperature performance through the use of intermediate circuits located towards the distal end of the high temperature pressure sensor as well as configurations to reduce thermally induced stresses within the pressure sensor are disclosed. The disclosed embodiments also detail ways in which to reduce signal loss due to various stray capacitances within the pressure sensor to improve signal fidelity and sensitivity.