Liquid Level Detection Probe with Dynamic Threshold Segmentation
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Solution Overview
Problem
Existing liquid level detection technologies in biochemical analyzers suffer from poor anti-interference performance and reduced sensitivity, particularly when detecting small amounts of liquid, leading to control errors and increased reagent and sample usage.
Innovation Solution
A liquid level detection apparatus and method utilizing a pipetting probe with a signal processing module that converts capacitance values into discrete signals, employing slope and amplitude detecting methods based on threshold values to improve sensitivity and anti-interference performance, allowing for precise control of the probe's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the comparison threshold of the comparison circuit is increased to improve anti-interference performance, then the reliability of detection is improved, but the sensitivity for detecting small amounts of liquid drops
Solution Approach 1:
The patent segments the liquid level detection process into multiple discrete signal levels (first liquid level, second liquid level, third liquid level) with corresponding threshold values (first threshold, second threshold, third threshold). This segmentation allows the system to use different threshold settings for different detection scenarios, thereby resolving the contradiction between reliability and sensitivity.
Solution Approach 2:
The patent implements dynamic threshold adjustment by introducing time-based logic where the threshold changes depending on the detection stage. The system dynamically switches between different threshold values (first, second, third thresholds) based on the current liquid level state, allowing optimal performance across varying conditions rather than using a fixed threshold.
2Reliability
If a fixed high threshold is used to improve anti-interference performance, then false detection is reduced, but the system cannot adapt to both large and small amounts of liquid
Solution Approach 1:
The patent implements dynamic threshold adjustment by introducing time-based logic where the threshold changes depending on the detection stage. The system dynamically switches between different threshold values (first, second, third thresholds) based on the current liquid level state, allowing optimal performance across varying conditions rather than using a fixed threshold.
Solution Approach 2:
The patent changes the threshold parameter dynamically during the detection process. By introducing multiple threshold values (first threshold Vl, second threshold Vh, third threshold V2) and switching between them based on detection stage and liquid volume, the system achieves both high reliability and adaptability to different liquid amounts.
3Measurement precision
If the detection sensitivity is increased to detect small amounts of liquid, then the required reagent and sample amount decreases, but the anti-interference performance deteriorates
Solution Approach 1:
The patent segments the liquid level detection process into multiple discrete signal levels (first liquid level, second liquid level, third liquid level) with corresponding threshold values (first threshold, second threshold, third threshold). This segmentation allows the system to use different threshold settings for different detection scenarios, thereby resolving the contradiction between reliability and sensitivity.
Solution Approach 2:
The patent implements dynamic threshold adjustment by introducing time-based logic where the threshold changes depending on the detection stage. The system dynamically switches between different threshold values (first, second, third thresholds) based on the current liquid level state, allowing optimal performance across varying conditions rather than using a fixed threshold.
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
Enhances detection sensitivity and anti-interference performance by adjusting threshold settings, enabling accurate liquid level detection for both large and small volumes of liquid, reducing reagent and sample requirements.
Implementation Method 1
the pipetting probe is susceptible to outside interference, and thus there is high requirement for the grounding of the sample disk... the inner and outer probe tubes are made by a medically used stainless steel and equivalent to two electrodes of a capacitance... When the tip of the probe is in contact with the liquid level, the dielectric constant between the two electrodes varies and thus the capacitance of the probe is changed
Data Source
AI summary
The present application discloses a method and apparatus for detecting liquid level with probe, and the method comprising steps of: (A) acquiring a capacitance value of the probe; (B) generating an analog signal corresponding to the acquired capacitance value; (C) converting the generated analog signal into discrete signals at a predetermined sampling interval; (D) increasing or decreasing a counting value according to an amplitude of each the discrete signals, and outputting a liquid level contacting indication signal when the counting value reaches a predetermined counting threshold; and (E) controlling a movement of the probe according to the output liquid level contacting indication signal.