Centrifugal Pump Segmented Scraper Impeller for Dry Matter

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Solution Overview

Problem

Centrifugal pumps used in applications with high dry matter content fluids face issues with dry matter buildup in the gap between the impeller and back plate, leading to increased friction, energy consumption, and reduced efficiency, necessitating frequent cleaning and potential motor overheating.

Innovation Solution

The centrifugal pump features an impeller with segmented scraper means comprising multiple protrusions that extend radially by ±10% to ±40% of the impeller radius, creating a scraping unit that maintains a clear area behind the impeller, reducing friction and energy consumption by preventing dry matter buildup through increased turbulence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If scraper bars are arranged on the back side of each vane to prevent dry matter buildup, then deposit formation is reduced, but friction increases and energy consumption rises

Engineering Contradiction:
Improvedeposit formationVSAvoidenergy consumption
Core Design Contradiction:
Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The scraper means are divided into multiple protrusions distributed on the back side of the impeller, creating segmented scraping units that collectively cover the gap area without requiring full circumferential contact, thereby reducing overall friction while maintaining effective scraping action

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protrusions are strategically positioned to provide localized scraping action only where dry matter deposition occurs most severely, rather than continuous scraping around the entire impeller periphery, optimizing the balance between deposit prevention and friction reduction

Inventive Principle:
Principle #3Local quality

2Duration of action of moving object

If scraper means are added to the impeller to prevent deposits, then operational time between cleanings is extended, but device complexity increases

Engineering Contradiction:
Improveoperational time between cleaningsVSAvoidimpeller structure complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The scraper protrusions are integrated directly into the impeller body as a unified structure, combining the pumping function and scraping function into a single component rather than adding separate scraping mechanisms, thus extending operational time without proportionally increasing complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The impeller performs self-cleaning through its own rotation, with the protrusions automatically scraping deposits as the impeller rotates, eliminating the need for separate cleaning mechanisms or additional moving parts

Inventive Principle:
Principle #25Self-service

3Object-generated harmful factors

If the radial extension of scraper means is increased to improve scraping coverage, then deposit prevention improves, but friction and energy consumption increase

Engineering Contradiction:
Improvedeposit buildupVSAvoidfriction force
Core Design Contradiction:
Object-generated harmful factorsVSForce

Solution Approach 1:

The protrusions extend radially by ±10% to ±40% of the impeller radius, providing sufficient scraping coverage to prevent deposit buildup in the critical gap area without excessive extension that would cause unnecessary friction and energy consumption

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The radial extension parameter of the protrusions is optimized within specific ranges (±10% to ±40% of impeller radius) to achieve the optimal balance between scraping effectiveness and friction minimization, adjusting the coverage area to match the actual deposit formation zone

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

This design prolongs the time between cleaning cycles, reduces energy consumption, and enhances operational efficiency by minimizing friction and deposit formation, allowing for longer production runs and reduced unproductive cleaning time.

Implementation Method 1

The multiple protrusions are arranged with a distance to each other, and at a various radius on the back side of the impeller... creating a scraping unit that maintains a clear area behind the impeller, reducing friction and energy consumption by preventing dry matter buildup through increased turbulence

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP2567097B1Centrifugal pump
Publication Date: 2019.06.26 ALFA LAVAL CORP AB
  • EP2567097B1 patent drawingFigure 1
  • EP2567097B1 patent drawingFigure 2~3
  • EP2567097B1 patent drawingFigure 4

AI summary

A centrifugal pump that comprises a casing in which an impeller (1) is arranged. The impeller (1) has a back side (2) that faces a back plate of the centrifugal pump, and one or more vanes (51-55) for pumping the fluid. The back side (2) of the impeller (1) comprises a segmented scraper (3) for scraping from the back plate material that has been deposited from the fluid. The segmented scraper (3) comprises multiple protrusions (101-118), wherein each protrusion of the multiple protrusions (101-118) is facing the back plate, and an aggregated radial extension of the protrusions (101-118) equals a radius of the impeller (1) within an interval of ± 10%, ± 25% or even up to ± 40%.