Capacitance Liquid Level Sensor with Dielectric Offset Correction
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Solution Overview
Problem
Conventional electrostatic capacitance methods for detecting liquid levels in containers face accuracy issues due to interference from surrounding dielectrics, particularly in small tanks where sensor size reduction compromises detection accuracy.
Innovation Solution
A recording apparatus with a first electrode on the container's surface and a second electrode positioned away, connected to a circuit that uses a reference sensor to correct for dielectric influences, allowing precise detection of the remaining content amount by subtracting the electrostatic capacity offset caused by dielectrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are disposed on the same tank to detect liquid levels at different heights, then detection accuracy is improved, but the size of the sensor assembly increases
Solution Approach 1:
The patent divides the detection function into multiple sensors positioned at different heights, where each sensor detects the electrostatic capacity at its specific level. This segmentation allows the system to capture liquid level information across different zones without requiring a single large sensor assembly, thereby maintaining detection accuracy while controlling overall size.
Solution Approach 2:
The patent transitions from a single-plane detection approach to a multi-level three-dimensional detection configuration. By positioning sensors at different vertical heights corresponding to different liquid levels, the system achieves comprehensive detection coverage in the vertical dimension, improving measurement precision without proportionally increasing the horizontal footprint.
2Volume of moving object
If sensor size is reduced to fit small tanks, then device compactness is improved, but detection accuracy deteriorates due to reduced detection region
Solution Approach 1:
The patent combines multiple sensors with different detection regions into a unified detection system. By integrating the electrostatic capacity values from multiple sensors at different heights, the system achieves comprehensive detection coverage that compensates for the limited detection region of each individual small sensor, thereby maintaining overall detection accuracy in compact tank configurations.
Solution Approach 2:
The patent employs multiple copies of the same sensor type positioned at different locations and heights. Each sensor is identical in structure but differs in position, allowing the system to replicate the detection function across multiple zones. This copying strategy enables accurate measurement in small tanks by aggregating information from multiple identical small sensors rather than relying on a single large sensor.
3Ease of operation
If electrostatic capacitance method is used to detect liquid level, then non-contact detection is achieved, but detection accuracy is reduced due to interference from surrounding dielectrics
Solution Approach 1:
The patent applies local quality by positioning sensors at specific locations and heights where the electrostatic field is most sensitive to liquid level changes. Each sensor is strategically placed to detect capacity changes in its local region, and the combined data from these localized measurements provides accurate overall liquid level detection while minimizing the influence of surrounding dielectrics through spatial differentiation.
Solution Approach 2:
The patent introduces the electrostatic capacity value as an intermediary parameter that mediates between the non-contact detection capability and the accuracy requirement. By measuring the electrostatic capacity at multiple levels and using this intermediary value to infer liquid level, the system achieves both non-contact detection and accurate measurement, with the multi-level capacity values serving as intermediate steps that compensate for dielectric interference.
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 enhances the accuracy of detecting the remaining content amount by isolating the sensor's electrostatic capacity from dielectric interference, providing reliable measurements even in small containers.
Implementation Method 1
employs an electrostatic capacitance method to detect a liquid level in a tank, by detecting an electrostatic capacity between a sensor and a liquid stored in the tank using the liquid as a dielectric
Implementation Method 2
detecting an electrostatic capacity between a sensor and a liquid stored in the tank using the liquid as a dielectric
Data Source
AI summary
A recording apparatus includes a storage unit, a first electrode, a second electrode, and a circuit. The storage unit stores a liquid or powder to be supplied to a recording portion configured to perform recording. The first electrode is positioned on an outer surface of the storage unit. The second electrode is positioned away from the storage unit. The circuit is connected to each of the first electrode and the second electrode.