Capacitance Level Sensing with Dual Electrode Temperature Compensation
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Solution Overview
Problem
Capacitance level sensing apparatuses face malfunctions due to variations in the dielectric constant of materials like water with temperature changes, leading to inaccurate level sensing.
Innovation Solution
A level sensing apparatus with a reference electrode and a level sensing electrode, both having different dimensions and dielectric layer thicknesses, allows for accurate level detection by using capacitance differences between the two electrodes, independent of temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitance level sensing is used, then level detection capability is provided, but measurement precision deteriorates due to temperature-induced dielectric constant variations
Solution Approach 1:
A reference electrode is introduced as an intermediary element to mediate between the temperature variations and the level sensing electrode. The reference electrode detects the dielectric constant changes caused by temperature, and this information is used to compensate for the measurements from the level sensing electrode, thereby maintaining measurement precision across varying temperatures.
Solution Approach 2:
The system implements feedback by continuously monitoring the capacitance changes in the reference electrode that reflect temperature-induced dielectric constant variations. This feedback information is then used to adjust or compensate the level measurements from the level sensing electrode, ensuring reliable and accurate level detection despite temperature fluctuations.
2Measurement precision
If a reference electrode is added for temperature compensation, then measurement precision improves, but device complexity increases
Solution Approach 1:
The reference electrode and level sensing electrode are merged into a single integrated sensing apparatus structure. Both electrodes are positioned on the container wall at different heights, sharing common support structures and signal processing circuits, which reduces overall device complexity while maintaining the precision benefits of temperature compensation.
Solution Approach 2:
The reference electrode serves multiple functions: it acts as a temperature compensation reference, provides a stability baseline for the sensing system, and can potentially serve as an additional level detection point. This multi-functionality reduces the need for separate temperature sensing components, thereby limiting the increase in device complexity.
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 precise level sensing without requiring additional temperature compensation, simplifying the apparatus and improving reliability across varying temperatures.
Implementation Method 1
a level sensing apparatus sensing a displacement level of a detected material by using a capacitance detected from two electrodes
Implementation Method 2
the capacitance level sensing apparatus senses the level of the detected material by using a capacitance increased as liquid, powdery particles, and the like having a dielectric constant larger than air ascend to be close to an electrode
Data Source
AI summary
There is provided a level sensing apparatus detecting the level of a detected material, the apparatus including: a circuit board; a first electrode and a second electrode having different dimensions, which are formed on one surface and the other surface of the circuit board; a first dielectric layer and a second dielectric layer having different thicknesses, which are formed on the first electrode and the second electrode; and a judgment unit electrically connected with the first electrode and the second electrode through the circuit board to judge the level of the detected material by using capacitances detected from the first electrode and the second electrode. According to the present invention, it is possible to accurately sense a level without being influenced by surrounding circumstances such as temperature, and the like.