Capacitive Level Sensor for Conductive Liquid Tanks
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Solution Overview
Problem
Existing liquid tanks with capacitive sensors for measuring electrically conductive liquids face challenges in assembly complexity and risk of sensor components coming into contact with the liquid, leading to potential damage and installation difficulties.
Innovation Solution
A capacitive sensor design where the dielectric and enclosure wall form a single piece with a projection creating a cavity for housing the first plate, allowing the sensor to be assembled externally without direct contact with the liquid, and using a hollow conductive piece for the first plate that can house additional components, eliminating the need for fixing means and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the capacitive sensor elements are arranged inside the enclosure to measure liquid level, then the measurement function is achieved, but the risk of liquid contact with sensitive components increases and assembly complexity increases
Solution Approach 1:
The sensor system is segmented into two distinct parts: the first plate (sensitive component) is arranged outside the enclosure, while the second plate (conductive liquid) is inside the enclosure. The dielectric element bridges these two spaces, allowing capacitive measurement without direct contact between sensitive components and liquid. This segmentation resolves the contradiction by physically separating the measurement function from liquid exposure.
Solution Approach 2:
The dielectric element acts as an intermediary between the first plate (outside the enclosure) and the conductive liquid (inside the enclosure). It enables capacitive coupling for level measurement while preventing direct contact between the sensitive first plate and the liquid, thus maintaining both measurement precision and component reliability.
2Ease of manufacture
If the wall is planar for simple construction, then manufacturing is simplified, but fixing sensor elements to the wall becomes difficult
Solution Approach 1:
The dielectric element is merged with the enclosure wall to form a unitary assembly. This integration eliminates the need for separate sensor mounting structures on the wall, as the dielectric itself becomes part of the capacitive sensor system. The wall maintains its simple planar construction for ease of manufacture, while the integrated dielectric provides the necessary sensor mounting functionality.
3Ease of operation
If sensor elements are exposed to liquid for measurement, then level detection is possible, but shock and contact damage risk increases
Solution Approach 1:
The sensor is segmented into a first plate positioned outside the enclosure and a second plate formed by the conductive liquid inside the enclosure. This segmentation allows level detection through capacitive coupling across the dielectric barrier, eliminating direct contact between sensitive components and liquid, thus preventing shock and contact damage while maintaining operational capability.
Solution Approach 2:
The dielectric element serves as an intermediary that enables level detection functionality while physically protecting the first plate from liquid exposure. It transmits the capacitive signal necessary for level measurement while blocking mechanical shock and contact damage from reaching the sensitive sensor components.
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 construction simplicity, prevents sensitive components from contacting the liquid, and facilitates easy assembly of the sensor, ensuring reliable operation and wide-range level measurement capabilities.
Implementation Method 1
a capacitive sensor for measuring the liquid level inside said enclosure, that can emit an output signal as a function of the liquid level inside said enclosure
Implementation Method 2
the dielectric, which can at least be partially inserted between said first plate and the electrically conductive liquid that can be contained inside the enclosure
Data Source
AI summary
A tank (1) of electrically conductive liquid (12) comprising an enclosure (2) for storage of the liquid (12) delimited by at least one wall (13), a capacitive sensor (5) for measuring the liquid level inside said enclosure (2), and a device (6) for processing the output signal of the sensor (5) outside of the enclosure (2) comprising, in order to form a capacitor, a dielectric (11) and a first frame (10) electrically connectable to a source (18) for supplying power and to the processing device. The first frame (10) is arranged outside the enclosure (2), the dielectric (11) can be at least partially interposed between said first frame (10) and the electrically conductive liquid (12) and the dielectric (11) is formed by at least one part (131) of the wall (13) delimiting the enclosure (2) suitable for coming into contact with the electrically conductive liquid (12) contained inside the enclosure (2).