Reagent Disk Control for Liquid Level Oscillation in Automated Analyzers
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Solution Overview
Problem
Automated analyzers face challenges in accurately measuring liquid levels in large-capacity reagent containers due to increased centrifugal force, leading to oscillation of the liquid surface, which affects reagent-dispensing accuracy and increases dead volume.
Innovation Solution
Implementing a control method where the reagent disk is operated with a longer moving distance in the first cycle and a reduced angular velocity in the last cycle, with a 1.5-second delay before starting the last cycle, to minimize liquid surface oscillation during liquid-level measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If reagent containers of larger capacities are used to increase the volume of reagents, then the quantity of substance is improved, but the liquid surface oscillation is augmented due to increased centrifugal force during faster rotation of the reagent disk
Solution Approach 1:
The reagent container is designed with a centrifugal proximal section and a centrifugal distal section that generate fluid resistance in the centrifugal direction before the liquid surface can oscillate significantly. This preliminary resistance counteracts the centrifugal force-induced oscillation, allowing large-capacity containers to rotate at higher speeds without excessive liquid surface instability
Solution Approach 2:
The container structure changes the physical parameters of the reagent system by introducing sections with different centrifugal force characteristics. The centrifugal proximal section (with smaller centrifugal force) and centrifugal distal section (with larger centrifugal force) create a gradient that controls liquid flow and suppresses oscillation during rotation
2Productivity
If the reagent disk rotates faster to increase processing speed, then the productivity is improved, but the oscillation of the liquid surface is augmented, causing errors in detection results
Solution Approach 1:
The specialized container structure with centrifugal resistance sections is designed to counteract oscillation before it can affect measurement accuracy. This allows the reagent disk to rotate at higher speeds for increased productivity while maintaining liquid level detection precision through the built-in damping mechanism
3Stability of the object's composition
If the oscillation of the liquid surface is suppressed by generating fluid resistance in centrifugal direction, then the stability of the liquid surface is improved, but the device complexity is increased due to the specialized container structure
Solution Approach 1:
Rather than making the entire container complex, only specific sections (centrifugal proximal section and centrifugal distal section) are designed with special geometry to generate fluid resistance. The rest of the container maintains a simple cylindrical shape, achieving liquid surface stabilization with minimal added complexity
Solution Approach 2:
The centrifugal proximal and distal sections serve multiple functions: they generate fluid resistance to suppress oscillation, guide liquid flow during rotation, and maintain structural integrity. This multi-functionality reduces the need for additional separate components, offsetting the complexity with functional consolidation
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 effectively reduces errors in liquid-level measurement results, maintaining reagent-dispensing accuracy even with large-capacity reagent containers, without impacting throughput.
Implementation Method 1
a capacitance-measuring unit (6) for measuring capacitance between the probe and the container
Implementation Method 2
Greater centrifugal force, therefore, works upon the reagent containers. Consequently, the increase in centrifugal force augments the oscillation of the liquid surface of a reagent
Data Source
AI summary
Disclosed is an automated analyzer intended for qualitative/quantitative analysis of blood, urine, and other biological samples, and including a reagent disk for mounting a plurality of reagent containers thereon, wherein any errors in liquid-level measurement due to oscillation of a reagent liquid surface during rotation of the reagent disk are minimized, even when reagent containers of a large capacity are mounted. If a predetermined constant cycle time is defined as one unit, the reagent disk with reagent containers mounted thereon is transported to a liquid-level detection position using at least two units when a liquid level of a reagent is measured.