Centrifugal Pump Impeller Openings Reduce Axial Thrust

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Solution Overview

Problem

Centrifugal pumps face significant axial thrust issues due to pressure differences across impeller faces, leading to efficiency losses and bearing damage, particularly in multistage pumps, with existing solutions either complicating internal passages or requiring disk elements of different diameters.

Innovation Solution

An impeller design featuring a first disk element coaxial with a second disk element, connected by angularly spaced vanes and with specifically shaped openings in the peripheral region of the second disk element to reduce axial thrusts, allowing for efficient operation without altering disk diameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional impeller design is used, then结构简单性 is maintained, but axial thrust generation increases causing efficiency losses and bearing damage

Engineering Contradiction:
Improveimpeller structureVSAvoidaxial thrust
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The impeller is segmented into a first disk element and a second disk element with vanes connecting them, creating a structured configuration that enables selective pressure management across different regions of the impeller

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Openings are specifically positioned in the peripheral region of the second disk element where high pressure acts, creating local pressure relief zones that reduce axial thrust while maintaining structural integrity and hydraulic performance in other areas

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If half of the impellers are keyed in the opposite direction, then axial thrust problems are addressed, but internal passage channel manufacturing becomes significantly difficult

Engineering Contradiction:
Improveaxial thrustVSAvoidinternal passage channels
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The invention changes the parameter of pressure distribution across the impeller by introducing openings in strategic locations, allowing uniform impeller design while achieving thrust balance through pressure equalization rather than directional keying

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If disk elements of different diameters are used, then axial thrust is reduced, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveaxial thrustVSAvoiddisk elements
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

Rather than using disk elements of different diameters, the invention uses openings of varying sizes and positions within the same disk element to create local pressure relief zones, achieving thrust reduction while maintaining uniform disk geometry for simplified manufacturing

Inventive Principle:
Principle #3Local quality

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 impeller design effectively reduces axial thrusts while maintaining maximum efficiency and head, preventing motor bearing damage by emptying high-pressure areas within the disk element, thus addressing traction issues on the transmission shaft.

Implementation Method 1

specifically shaped openings formed in the substantially peripheral region of said second disk element, between pairs of adjacent vanes, substantially at the areas subjected to the greatest axial thrust

Methodology Applied
Scientific EffectPressure equalization: Pascal's Law

Data Source

PatentEP3271587B1Impeller for centrifugal pumps
Publication Date: 2023.07.12 EBARA CORP
  • EP3271587B1 patent drawingFigure 1~2
  • EP3271587B1 patent drawingFigure 3~4
  • EP3271587B1 patent drawingFigure 5~6

AI summary

An impeller for centrifugal pumps has a first disk element, functionally arranged toward the inlet, which is coaxial to and faces a second disk element, which is functionally arranged toward the delivery and is connected rigidly to the first disk element by virtue of a series of angularly spaced vanes and is provided centrally with a means for fixing to a transmission shaft. The particularity of the present invention resides in that the impeller includes a series of openings formed in the substantially peripheral region of the second disk element, between pairs of adjacent vanes, substantially at the areas subjected to the greatest axial thrust.