Bearingless Centrifugal Pump Housing for Rotor Tilt Stabilization

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Solution Overview

Problem

Centrifugal pumps with bearingless motors face limitations in passive magnetic stabilization against axial displacements and tilting, which can compromise safe and trouble-free operation, especially in applications involving sensitive or aggressive substances.

Innovation Solution

The design incorporates a pump housing with indentations that generate local turbulence, reducing forces acting on the rotor and improving passive magnetic stabilization by altering flow conditions, thereby alleviating the load on magnetic bearings and enhancing stability against axial displacements and tilting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rotor is passively magnetically supported in the axial direction, then the design remains simple and compact, but the passive magnetic stabilization against axial displacements and tilting is insufficient

Engineering Contradiction:
Improvepassive magnetic stabilizationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pump housing features localized indentations (dimples) at specific positions on the suction and pressure sides. These indentations create local turbulence zones that generate stabilizing forces on the rotor, providing enhanced passive magnetic stabilization only where needed rather than requiring a complete redesign of the entire magnetic bearing system.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention utilizes fluid dynamic forces generated by the pumped medium itself to stabilize the rotor. The indentations create turbulence in the fluid flow, generating hydraulic forces that counteract axial displacements and tilting, thereby using the process fluid to enhance stabilization without adding mechanical components.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If geometric barriers or pressure equalization bores are added to improve stabilization, then reliability improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improverotor stabilizationVSAvoidease of manufacture
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Rather than adding complex geometric barriers or pressure equalization bores throughout the housing, the invention uses simple localized indentations at specific critical locations. These indentations are much easier to manufacture using standard machining or molding techniques, while still achieving the desired stabilization effect through localized turbulence generation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention extracts the essential stabilization function from complex geometric barriers and simplifies it into basic indentations. By removing unnecessary complexity and retaining only the critical turbulence-generating features, the design achieves reliable stabilization with significantly improved manufacturability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution significantly improves the passive magnetic stabilization of the rotor, reducing the forces and tilting moments acting on it, leading to more reliable operation in sensitive and aggressive environments without requiring geometric barriers or pressure equalization bores.

Implementation Method 1

The electrical windings of the stator generate a rotating magnetic field that exerts a torque on the rotor, causing it to rotate

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

also applies an adjustable lateral force to the rotor, allowing its radial position to be actively controlled or regulated

Methodology Applied
Scientific EffectMagnetic force: Magnetic Field

Implementation Method 3

the rotor is passively magnetically supported and stabilized by reluctance forces

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Implementation Method 4

at least one indentation is provided in the bottom and/or in the cover, which is designed to generate local turbulence

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP3795836B1Centrifugal pump
Publication Date: 2024.11.27 LEVITRONIX GMBH(CH)
  • EP3795836B1 patent drawingFigure 1
  • EP3795836B1 patent drawingFigure 2~3
  • EP3795836B1 patent drawingFigure 4~5

AI summary

A centrifugal pump for conveying a fluid is proposed, comprising a pump housing (2) in which a rotor (3) for conveying the fluid is provided, and a stator (4) which forms an electromagnetic rotary drive with the rotor (3) for rotating the rotor (3) about an axial direction (A), wherein the stator (4) is designed as a bearing and drive stator, with which the rotor (3) can be magnetically driven without contact and magnetically supported without contact with respect to the stator (4), wherein the rotor (3) is passively magnetically supported in the axial direction (A), and actively magnetically supported in a radial plane perpendicular to the axial direction (A), wherein the pump housing (2) comprises a base (27) and a cover (25), wherein the rotor (3) is arranged between the base (27) and the cover (25) in the pump housing (2) with respect to the axial direction (A).and wherein at least one indentation (9) is provided in the base (27) and/or in the lid (25), which is designed to generate local turbulence. The invention further proposes a pump housing (2) for such a centrifugal pump (1).