Draft Tube Agitator Blade Curvature for Homogeneous Mixing

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Solution Overview

Problem

Existing stirring devices lack optimal fluidic properties, leading to inefficient mixing, potential dead spaces, and increased shear forces on particles and crystals, which can result in caking and incrustations.

Innovation Solution

A guide tube stirring device with a rotor blade element having a substantially circular arc-shaped outer contour, comprising a flat first region and a curved second region, is designed for efficient fluid conveying, featuring a hub element connected to a drive shaft and made from materials resistant to solvents and acids, with a casing unit that adapts to the guide tube for homogeneous flow and reduced shear forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional stirring devices are used, then mixing function is provided, but fluidic properties are suboptimal leading to dead spaces and inefficient mixing

Engineering Contradiction:
Improvemixing efficiencyVSAvoidfluidic properties
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The rotor blade element features a circular arc-shaped outer contour with a specific radius of curvature that is at least 20% of the blade element length. This curved geometry eliminates dead spaces and improves fluid flow patterns, ensuring complete mixing without stagnant regions while maintaining reliable fluidic properties throughout the mixing chamber.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If conventional stirring devices are used, then mixing is performed, but shear forces on particles and crystals are increased causing caking and incrustations

Engineering Contradiction:
Improvemixing functionVSAvoidshear forces on particles and crystals
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The stirring device incorporates a guide tube with specifically optimized geometric parameters including a diameter ratio and length-to-diameter ratio. The guide tube geometry creates controlled flow patterns that distribute shear forces uniformly throughout the fluid, preventing localized high shear zones that would cause particle caking and crystal incrustations while maintaining effective mixing.

Inventive Principle:
Principle #3Local quality

3Reliability

If rotor blade element with circular arc-shaped contour is used, then homogeneous fluid mixing is achieved, but device complexity increases

Engineering Contradiction:
Improvehomogeneity of mixingVSAvoidblade element geometry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The circular arc-shaped rotor blade element is defined by a single critical parameter: the radius of curvature, which is specified as at least 20% of the blade element length. This parameter-based design approach simplifies manufacturing while ensuring homogeneous mixing, as the curved geometry naturally eliminates dead spaces and promotes uniform fluid circulation without requiring complex multi-component structures.

Inventive Principle:
Principle #35Parameter changes

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

The design achieves efficient and homogeneous fluid mixing, reduces shear forces, and prevents caking and incrustations, ensuring a high level of homogeneity and product-friendly conveying.

Implementation Method 1

at least one stirring unit (12) rotatable about an axis of rotation (10), which is provided for conveying a fluid in an axial conveying direction (16)

Methodology Applied
Scientific EffectFluid conveying:

Implementation Method 2

reduces shear forces, and prevents caking and incrustations

Methodology Applied
Scientific EffectShear force reduction: Shear Stress

Data Source

PatentEP3386619B1Mixing apparatus
Publication Date: 2023.12.20 EKATO RUHR & MISCHTECHN
  • EP3386619B1 patent drawingFigure 1
  • EP3386619B1 patent drawingFigure 2
  • EP3386619B1 patent drawingFigure 3~4

AI summary

Disclosed is an agitator device, in particular a draft tube agitator device, comprising at least one agitator unit (12a; 12b) that can rotate about a rotational axis (10a) and that is provided for the delivery of a fluid in an axial delivery direction (16a; 16b). The agitator unit has at least one rotor blade element (18a), a section of which that projects on a plane perpendicular to the rotational axis (10a) having an at least substantially arced outer contour (20a), and the rotor blade element (18a) has at least one first substantially planar region (24a) lying on a blade plane (22a) and a second region (26a) curving away from the blade plane (22a).