Reciprocating Stir Rod for Viscous Biochemical Mixing

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Solution Overview

Problem

In biochemical automatic analyzing devices, the flow of a solution separates into multiple layers during stirring, leading to decreased uniformity, especially in narrow sample cells with large reaction volumes and high viscosity solutions, making it difficult to achieve efficient mixing in a short time.

Innovation Solution

A stir rod is rotated and vertically reciprocated simultaneously to eliminate the boundary surface between layers, enhancing the propagation of substances and improving mixing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a stir rod is rotated in a narrow sample cell with large reaction volume and high viscosity solution, then the solution is stirred, but the flow separates into multiple layers decreasing uniformity

Engineering Contradiction:
Improvestirring speedVSAvoidsolution uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The stir rod performs both rotation and vertical reciprocation simultaneously, creating a dynamic stirring motion that prevents flow separation into layers. The vertical reciprocating movement disrupts the steady-state laminar flow that causes layering, while the rotation provides mixing force, achieving both high stirring speed and solution uniformity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention adds a vertical dimension to the traditional rotational stirring motion. By making the stir rod reciprocate vertically while rotating, the stirring action extends from a single-plane rotation to a three-dimensional motion, effectively breaking up horizontal flow layers and improving substance propagation between layers

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the reaction volume is increased in a narrow sample cell, then more reagent can be analyzed, but the number of layers formed by separation increases

Engineering Contradiction:
Improvereaction volumeVSAvoidsolution uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The combined rotation and vertical reciprocation creates a dynamic stirring pattern that adapts to larger reaction volumes. The vertical movement ensures that even in larger volumes, the flow remains disrupted and mixed, preventing layer separation that would otherwise occur with increased volume in narrow cells

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the stirring parameters by introducing vertical reciprocation frequency and amplitude in addition to rotation speed. These parameter changes enable effective mixing in larger reaction volumes by creating more complex flow patterns that prevent layer formation

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the viscosity of the reaction solution is increased, then more complex biochemical analysis can be performed, but the rate of propagation of substance between layers decreases

Engineering Contradiction:
Improvebiochemical analysis capabilityVSAvoidsubstance propagation rate
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The dynamic combination of rotation and vertical reciprocation creates stronger mixing forces that overcome the resistance of high viscosity solutions. The vertical reciprocating motion generates turbulence and flow disruption that enhances substance propagation rates even in highly viscous biochemical solutions

Inventive Principle:
Principle #15Dynamics

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 scrambles the flow, increasing substance propagation between layers and enhancing stir efficiency, particularly in small sample cells, resulting in improved uniformity of the reaction solution.

Implementation Method 1

a stir rod is rotated and vertically reciprocated at the same time to efficiently mix a sample and a reagent or a reaction solution to be stirred. By vertically reciprocating a stir rod during a stir operation of rotating the stir rod in a reaction solution, a boundary surface between layers of flow generated in the steady state disappears and the rate of propagation of a substance increases

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP2320238B1Automatic analyzing device
Publication Date: 2020.09.23 HITACHI HIGH TECH CORP
  • EP2320238B1 patent drawingFigure 1
  • EP2320238B1 patent drawingFigure 2A~2C
  • EP2320238B1 patent drawingFigure 3A~3C

AI summary

A reaction solution is mixed in a short period of time with excellent stir efficiency. A stir rod 19 is vertically reciprocated in a reaction solution 7 during the stirring of the solution.