Automatic Analyzer Reagent Dispensing Nozzle Pressing

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Solution Overview

Problem

Existing automatic analyzers face challenges in accurately measuring blood clotting ability due to air bubble entrainment and the need for a stirring mechanism, which affects reproducibility and increases costs, especially in blood clotting reactions where clotting occurs quickly and adheres to stirring bars, and requires precise reagent dispensing.

Innovation Solution

The automatic analyzer employs a reagent dispensing mechanism where the nozzle presses against the inner wall of the reaction vessel to maintain a constant dispensing position, preventing air bubble entrainment and using the momentum of the discharged reagent for mixing, eliminating the need for a stirring mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a stirring bar is used to stir the mixed liquid of sample and reagent, then the blood clotting reaction can proceed stably, but the clotting material adheres to the stirring bar and causes cross-contamination between subsequent samples

Engineering Contradiction:
Improvestability of blood clotting reactionVSAvoidaccuracy of analysis
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The invention removes the stirring bar from the reaction vessel after the reaction is complete, extracting the problematic element that causes cross-contamination. The stirring bar is taken out and cleaned separately, preventing clotting material from being carried over to the next sample while maintaining reaction stability during the measurement period.

Inventive Principle:
Principle #2Taking out (Extraction)

2Stability of the object's composition

If a stirring mechanism is used to mix sample and reagent, then the reaction proceeds uniformly, but the device complexity and cost increase

Engineering Contradiction:
Improveuniformity of reactionVSAvoidcomplexity of stirring mechanism
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention employs the self-mixing effect where the reagent jet itself creates turbulence and mixing through its own discharge momentum. The reagent flows directly onto the sample, and the kinetic energy of the discharge automatically stirs the mixture without requiring an external stirring mechanism, achieving uniform reaction while simplifying the device structure.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the nozzle dispenses reagent without pressing against the inner wall, then the dispensing mechanism is simpler, but air bubbles are entrained in the mixed liquid and reduce measurement accuracy

Engineering Contradiction:
Improvesimplicity of dispensing mechanismVSAvoidaccuracy of optical measurement
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The nozzle is pressed against the inner wall of the reaction vessel before reagent dispensing to establish a proper flow path. This preliminary positioning action ensures that the reagent flows smoothly along the wall surface, preventing air bubble entrapment from the outset while maintaining a relatively simple dispensing mechanism structure.

Inventive Principle:
Principle #10Preliminary action

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 ensures accurate and reproducible blood clotting ability measurements by preventing air bubble disturbance and reducing costs and space requirements, as the reagent is consistently dispensed without a stirring mechanism, maintaining high precision in optical measurements.

Implementation Method 1

using the momentum of the discharged reagent for mixing

Methodology Applied
Scientific EffectMomentum: Conservation of Momentum

Data Source

PatentEP3076183B1Automatic analyzer
Publication Date: 2021.06.30 HITACHI HIGH TECH CORP
  • EP3076183B1 patent drawingFigure 1~2
  • EP3076183B1 patent drawingFigure 3~4
  • EP3076183B1 patent drawingFigure 5~6

AI summary

If an air bubble is entrained when a reagent is added to a sample, disturbance caused by this air bubble may prevent accurate optical measurement, thereby reducing accuracy for measuring blood clotting ability. The position to dispense the reagent depends on accuracy of stopping a reagent dispensing mechanism and dimensional errors of individual detectors, and thus conventional reagent discharging method may entrain an air bubble because a distance between a nozzle for dispensing the reagent and an inner wall of a reaction vessel is not constant and conditions for dispensing the reagent to the sample vary each time. In the present invention, an automatic analyzer with a nozzle for sucking and discharging the reagent for blood clotting reaction is provided with a dispensing mechanism that keeps a constant position for the nozzle to discharge the reagent by pressing the nozzle against the inner wall of the reaction vessel within the elastic range.