Capacitive Level Sensor Array with Reference Wires
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Solution Overview
Problem
Capacitive fluid level sensors require time-consuming compensation and calibration, which is inconvenient for detecting liquids in tanks, pipes, and vessels.
Innovation Solution
A capacitive sensor system with a continuous sensor wire, ground wire, wet reference wire, and dry reference wire within a tube, where the wet reference wire is exposed at the lower end and the dry reference wire is exposed at the upper end, allowing for accurate capacitance measurements and compensation for dielectric changes and environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If prior art capacitive sensors are used, then fluid level detection is achieved, but compensation and calibration are time-consuming and inconvenient
Solution Approach 1:
The patent applies preliminary action by pre-configuring the sensor array with multiple conductors at different positions (including reference conductors above and below the measurement range) during manufacturing. This allows the sensor to automatically compensate for dielectric changes and environmental factors without requiring field calibration, eliminating the time-consuming calibration step that plagues prior art sensors.
Solution Approach 2:
The patent utilizes parameter changes by measuring capacitance values at multiple conductor positions and using these variations to compensate for environmental factors. The reference conductors provide baseline capacitance measurements that allow the system to distinguish between actual level changes and changes caused by temperature, humidity, or dielectric constant variations, thereby eliminating calibration needs.
2Measurement precision
If insulated electrodes are placed in media for capacitance sensing, then level detection is achieved, but compensation for dielectric changes and environmental factors is required
Solution Approach 1:
The patent applies segmentation by dividing the sensing function across multiple discrete conductors positioned at different locations along the tube. Each conductor provides a localized capacitance measurement, and by comparing these segmented measurements, the system achieves accurate level detection while simultaneously compensating for environmental factors, without requiring a single complex sensor structure.
Solution Approach 2:
The patent uses reference conductors as intermediaries to mediate between the measurement conductors and the environmental factors. These reference conductors, positioned where they should not be affected by the measured phenomenon (above the maximum level or below the minimum level), serve as mediators that provide baseline data for compensating dielectric and environmental changes, thereby simplifying the overall measurement system.
3Measurement precision
If multiple conductors are used for compensation, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the sensor array where multiple conductors serve dual purposes: measurement conductors detect fluid levels while also serving as reference points for compensation, and reference conductors simultaneously provide environmental compensation and define the measurement range. This multi-functionality allows accurate measurement with enhanced compensation without proportionally increasing 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 and efficient fluid level sensing by determining output fluid levels based on sensed capacitance, wet reference, and dry reference values, reducing interference and calibration needs.
Implementation Method 1
When the insulated electrodes are placed in the presence of media a corresponding change in capacitance results. This change is interpreted as a change in level and/or presence of liquid.
Implementation Method 2
A wet reference capacitance value is determined via a wet reference wire... A dry reference capacitance value is determined via a dry reference wire... An output fluid level is determined based on the sensed fluid capacitance level, the wet reference capacitance value, and the dry reference capacitance value.
Data Source
AI summary
Systems, apparatuses, and methods provide for a fluid level sensor including a continuous sensor wire located within a tube, where the continuous sensor wire runs from an upper end of the tube to a lower end of the tube. A ground wire is located within the tube, where the ground wire runs from the upper end of the tube to the lower end of the tube. A wet reference wire is located within the tube, where the wet reference wire runs from the upper end of the tube to the lower end of the tube. A dry reference wire is located within the tube, wherein the dry reference wire is located adjacent the upper end of the tube.