Liquid Surface Detection in Modular Analyzers
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Solution Overview
Problem
Conventional automatic multi-purpose analyzers face challenges in accurately detecting liquid surface levels due to discharge noise and vibration, leading to incorrect surface detection and reduced analysis efficiency, especially in modularized systems where multiple analysis units rely on unreliable capacitive probes.
Innovation Solution
The system employs a reliable liquid surface detection method that measures the surface height before lowering the probe, generating a reset signal 3 millimeters above the surface to ignore discharge noise, and shares surface level information between analysis units, ensuring accurate detection and reducing incorrect readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive probe is lowered into a vessel to detect liquid surface, then surface detection capability is provided, but discharge noise and vibration during lowering cause incorrect surface detection
Solution Approach 1:
The system performs preliminary surface height measurement using a reliable liquid surface method before lowering the capacitive probe. The measurement position and surface height information are recorded in advance, allowing the probe to be lowered without continuous monitoring. This preliminary action eliminates discharge noise and vibration interference during the lowering process, as the surface detection is based on pre-measured data rather than real-time capacitive sensing during insertion.
2Measurement precision
If continuous monitoring is required while probe is lowered, then surface detection is possible, but analysis time increases and throughput decreases
Solution Approach 1:
The system performs the surface height measurement and stores the information before the probe lowering operation begins. This preliminary measurement eliminates the need for continuous monitoring during probe insertion, allowing the probe to be lowered at constant speed without intermittent stopping for surface detection. As a result, analysis time is reduced and throughput is improved while maintaining measurement precision.
Solution Approach 2:
The system uses the previously measured surface height information to automatically determine the correct insertion depth without requiring real-time feedback or continuous monitoring during probe lowering. The probe operation becomes self-guided by the pre-stored surface position data, eliminating the need for active monitoring and improving operational efficiency.
3Reliability
If multiple analysis units use separate surface detection, then each unit can detect surface independently, but redundant detection increases time consumption
Solution Approach 1:
The system enables multiple analysis units to share the same surface height information measured by the first analysis unit. The measured surface position data is stored and reused by subsequent analysis units, allowing them to perform their operations without repeating the surface detection process. This multi-functional use of the measurement data eliminates redundant detection time while maintaining detection reliability across all units.
Solution Approach 2:
The system implements a feedback mechanism where the surface height information measured by the first analysis unit is fed back to and stored by subsequent analysis units. This feedback loop allows later units to use the pre-measured data, eliminating the need for them to perform independent surface detection. The feedback mechanism reduces time consumption while ensuring all units operate with accurate surface position information.
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 approach enhances the reliability of liquid surface detection, improves analysis efficiency by reducing incorrect surface detection, and allows for more precise analysis across multiple modular units, thereby increasing the throughput of the automatic multi-purpose analyzer.
Implementation Method 1
With the capacitive probe, capacitance fluctuation from a certain timing is monitored and, when the liquid surface is judged, lowering operation of the probe is stopped.
Data Source
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AI summary
An automatic multi-purpose analyzer performs qualitative and quantitative analysis of biological samples such as blood, urine, etc. More particularly, an automatic modularized multi-purpose analyzer having a plurality of analysis units connected in series through a transfer line for transferring the sample, wherein failure caused by incorrect surface detection is resolved. An automatic multi-purpose analyzer having a plurality of analysis units connected in series through a transfer line for transferring a sample, each analysis unit including a pipetting mechanism for pipetting the sample, wherein each of the analysis units includes a transmission mechanism for transmitting information about the amount of sample, obtained upon sample pipetting by the pipetting mechanism of each analysis unit, to other analysis units.