Capacitive Water Level Sensor Using Charging Time Measurement
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Solution Overview
Problem
Existing water level measuring devices using capacitive techniques face challenges in achieving accurate measurements due to temporal changes in sensor materials and medium conditions, limiting their application to specific types of water, and require improved precision and reliability.
Innovation Solution
A water level measuring device with a pair of electrodes, where a first electrode made of steel is arranged in a C-shape and a second electrode formed of electric wire, using a comparator-based circuit to determine voltage matching points, calculates reference charging time to convert into capacitance for accurate water level determination, independent of medium conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If factory-calibrated capacitance measurement is used, then measurement precision is maintained initially, but measurement accuracy deteriorates over time due to material aging and medium condition changes
Solution Approach 1:
The patent transitions from measuring absolute capacitance values to measuring charging time parameters. By timing how long it takes for the capacitor to charge to specific voltage thresholds (first voltage and second voltage), the system obtains measurements that are independent of capacitance drift caused by material aging or medium changes, thus maintaining reliability over time while preserving measurement precision
Solution Approach 2:
The system implements a feedback mechanism where the measured charging time is continuously used to determine water level. The control unit monitors the charging process through the comparison unit, detects when voltage thresholds are reached, and uses this feedback information to calculate water level, creating a closed-loop system that compensates for environmental variations
2Measurement precision
If complex capacitance measuring circuits are used to improve precision, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex capacitance measurement circuits with a simpler timing-based electrical system. Instead of using precision capacitance meters or complex RC time constant measurement circuits, the invention uses a voltage source, comparison unit, and timer to measure charging time, significantly reducing circuit complexity while maintaining or improving measurement precision
Solution Approach 2:
The system uses simple, inexpensive components such as voltage sources, comparators, and timers instead of expensive precision capacitance measurement equipment. The electrode structure itself is simple and can be easily replaced if needed, reducing overall system cost and complexity
3Reliability
If traditional water level gauges are used, then measurement function is provided, but manufacturing cost and installation complexity increase
Solution Approach 1:
The electrode is divided into multiple segments (first electrode with first, second, and third parts) that can be independently configured. This segmentation allows flexible installation in different water level scenarios and simplifies manufacturing by allowing modular assembly, reducing both manufacturing cost and installation complexity while maintaining reliable measurement function
Solution Approach 2:
The measuring device is designed to be universally applicable to various water level measurement scenarios. The same basic structure and measurement principle can be used for different tank sizes, water types, and installation environments, eliminating the need for specialized expensive gauges for each application and simplifying both manufacturing and installation
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 method allows for accurate water level measurement with reduced manufacturing costs and simplified structure, enhancing reliability and ease of installation, while minimizing maintenance burdens for large-scale water level gauge networks.
Implementation Method 1
a water level measuring device with a pair of electrodes, where a first electrode made of steel is arranged in a C-shape and a second electrode formed of electric wire, using a comparator-based circuit to determine voltage matching points, calculates reference charging time to convert into capacitance for accurate water level determination
Data Source
AI summary
Disclosed in one embodiment are a device for measuring water level by using a capacitive technique, and a method therefor. A device for measuring water level comprises: an electrode unit which includes a first electrode and a second electrode arranged in parallel in a lengthwise direction, and which allow voltages to be applied to the first electrode and the second electrode; and a control unit for measuring the applied voltages, calculating the amount of reference charging time it takes to reach a second voltage from a predetermined first voltage on the basis of the measured voltages, and determining water level on the basis of the calculated reference charging time.