Liquid Sensor With Inner Electrodes For Vibration-Resistant Level Detection
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Solution Overview
Problem
Existing liquid sensors face challenges in accurately detecting the liquid level due to vibrations, which cause changes in the distance between electrodes, leading to inaccurate capacitance readings and liquid level detection.
Innovation Solution
A liquid sensor design with electrodes formed on the inner circumferential surface of a substrate, where the substrate has a rectangular shape with a hole, ensuring the electrodes remain perpendicular to the liquid surface, preventing liquid accumulation and maintaining consistent distance, and optionally incorporating a fluororesin substrate for durability and a light-emitting element for liquid quality detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrodes are arranged in a tubular configuration with a substrate, then liquid level detection is enabled, but the distance between electrodes changes due to vibration causing inaccurate detection
Solution Approach 1:
The substrate is divided into multiple independent support portions that individually support different sections of the first electrode. This segmentation allows each support portion to independently accommodate vibration without causing relative displacement between electrodes, thereby maintaining detection stability while enabling liquid level detection.
Solution Approach 2:
The substrate is designed with localized support portions at specific positions along the first electrode, providing differential support characteristics. The support portions are strategically positioned to maintain electrode spacing in critical measurement regions while allowing flexibility in other areas, resolving the contradiction between detection accuracy and vibration resistance.
2Measurement precision
If the substrate uses a rigid structure to maintain electrode distance, then detection accuracy is improved, but the device becomes more complex and difficult to manufacture
Solution Approach 1:
The substrate is designed as a thin, flexible film with integrated support portions rather than a rigid complex structure. This flexible substrate maintains electrode spacing through its inherent mechanical properties and support portion geometry, simplifying manufacturing while ensuring detection accuracy. The flexible nature also provides vibration damping capabilities.
3Measurement precision
If the electrodes are positioned perpendicular to the liquid surface, then liquid accumulation between electrodes is prevented, but the substrate orientation becomes more constrained
Solution Approach 1:
The substrate and electrodes are designed with asymmetric geometry where the first electrode and support portions are configured to naturally orient perpendicular to the liquid surface when installed. This asymmetric design provides a preferred installation orientation that prevents liquid accumulation while maintaining reasonable installation flexibility through the flexible substrate material.
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
The design allows for accurate liquid level detection even under vibration, with enhanced precision and the ability to detect liquid quality using a shared substrate, ensuring reliable operation in harsh environments.
Implementation Method 1
The detection circuit is configured to detect capacitance between the first and second electrodes
Implementation Method 2
first and second optical waveguides are embedded in the substrate, one end of the first optical waveguide faces one end of the second optical waveguide via the hole, the light-emitting element is attached to another end of the first optical waveguide, the light-receiving element is attached to another end of the second optical guide
Data Source
AI summary
Provided is a liquid sensor capable of relatively accurately detecting the liquid level even if vibration or the like occurs. The liquid sensor is configured to detect a liquid level in a state in which at least a portion of the liquid sensor is immersed in liquid. This liquid sensor includes a substrate. The substrate is provided with a hole. An inner circumferential surface of the substrate is formed around the hole. A first electrode and a second electrode facing the first electrode are formed on the inner circumferential surface. The liquid sensor further includes a detection circuit. The detection circuit is configured to detect capacitance between the first and second electrodes.