Agitator Arrangement With Dual Impellers And Integrated Cleaning

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Solution Overview

Problem

Current agitator arrangements in the food and beverage industry fail to provide efficient mixing, cost-effectiveness, and adequate cleaning while maintaining agitation capacity, especially in larger tanks, and often struggle with contamination risks.

Innovation Solution

An agitator arrangement featuring a rotatable hollow shaft with two axially displaced impellers, where the second impeller has a plurality of openings for spraying a cleaning liquid onto the first impeller, enabling improved agitation, efficient cleaning, and cost-effective design by utilizing the impeller hub for both securing blades and spraying cleaning liquid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single impeller is used in the agitator arrangement, then the device complexity is reduced, but the agitation efficiency and mixing performance deteriorate

Engineering Contradiction:
Improvestructure complexityVSAvoidagitation efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The agitator arrangement is segmented into multiple impellers (at least two impellers) positioned at different axial locations along the shaft. Each impeller contributes to the mixing action, providing enhanced agitation efficiency and better liquid circulation patterns compared to a single impeller system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces axial positioning of multiple impellers at different heights along the shaft, adding a vertical dimension to the mixing action. This multi-level arrangement creates more comprehensive liquid circulation and enhances overall agitation performance throughout the tank volume.

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

2Reliability

If cleaning liquid is sprayed on the first impeller using additional cleaning units, then the cleaning effectiveness is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The second impeller is designed with dual functionality: it performs both mixing/agitation and cleaning functions. The impeller hub incorporates spray openings that direct cleaning liquid onto the first impeller, eliminating the need for separate cleaning units and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cleaning function is merged with the second impeller structure. The spray openings are integrated into the impeller hub, combining the cleaning mechanism with the agitation component, thereby reducing the number of separate parts and simplifying the overall agitator arrangement.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the plurality of openings are located in additional cleaning units, then the cleaning coverage is improved, but the manufacturing cost and device complexity increase

Engineering Contradiction:
Improvecleaning coverageVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The second impeller serves multiple purposes: agitation through its blades and cleaning through its hub spray openings. This multi-functionality eliminates the need for separate cleaning units, reducing manufacturing costs while maintaining adequate cleaning coverage of the first impeller.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cleaning openings are merged into the second impeller hub structure, combining two functions (agitation and cleaning) into a single component. This integration reduces the total number of parts, simplifies manufacturing, and lowers overall system cost.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If two axially displaced impellers are used, then the agitation capacity is improved, but the device complexity increases

Engineering Contradiction:
Improveagitation capacityVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The agitator system is divided into multiple impeller units positioned at different axial locations. This segmentation allows each impeller to handle a portion of the mixing task, collectively providing enhanced agitation capacity that exceeds what a single impeller could achieve.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second impeller is designed to perform both agitation and cleaning functions, making it a multi-functional component. This approach increases agitation capacity while minimizing the increase in device complexity, as the additional impeller serves dual purposes rather than adding a dedicated cleaning mechanism.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design enhances liquid agitation, allows for the use of larger tanks with maintained agitation capacity, and ensures effective cleaning of the agitator arrangement, reducing contamination risks and manufacturing costs.

Implementation Method 1

The second impeller comprises a plurality of openings configured for spraying a cleaning liquid on the first impeller for cleaning the first impeller

Methodology Applied
Scientific EffectSpray: Spray

Implementation Method 2

The rotatable shaft thus has dual functionality in terms of transmitting rotational motion to the impellers and conveying pressurized cleaning liquid from a source outside of the mixing tank to the openings of the second impeller

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3581262B1Agitator arrangement
Publication Date: 2021.11.17 ALFA LAVAL CORP AB
  • EP3581262B1 patent drawingFigure 1
  • EP3581262B1 patent drawingFigure 2
  • EP3581262B1 patent drawingFigure 3

AI summary

The present disclosure relates to an agitator arrangement (2) for mixing a liquid in a mixing tank (1) and for cleaning the mixing tank (1). The agitator arrangement (2) comprises a rotatable hollow shaft (4) extending in an axial direction (5), a first impeller (7) secured to the shaft (4) at a first axial position, and a second impeller (8) secured to the shaft (4) at a second axial position. Moreover, the second impeller (8) comprises a plurality of openings (9) configured for spraying a cleaning liquid on the first impeller (7) for cleaning the first impeller (7). The present disclosure also relates to a mixing tank (1) including an agitator arrangement (2), wherein the first impeller (7) is located above the second impeller (8).