Single-Piece Centrifugal Pump Rotor for Leak-Free Magnetic Bearing

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Solution Overview

Problem

Existing centrifugal pumps with contactless magnetically levitated rotors face challenges in manufacturing complexity and operational reliability due to the need for assembling multiple components and potential leaks at welded joints, which can lead to contamination, especially in sensitive applications like the semiconductor industry.

Innovation Solution

A pump unit with a rotor designed as a single-piece unit, incorporating blades, a separating element, and relief openings, manufactured through injection molding, eliminating the need for assembly and reducing the risk of leaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple components are assembled to form the rotor (blades, separating element, relief openings as separate parts), then the rotor can be manufactured with complex functions, but the manufacturing complexity increases and operational reliability decreases due to potential leaks at welded joints

Engineering Contradiction:
Improvefunctional complexityVSAvoidoperational reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines the blades, separating element, and relief openings into a single-piece rotor component manufactured by injection molding. This merging eliminates the need for assembling multiple separate parts and welding joints, thereby preventing leaks while maintaining all necessary functions (fluid pumping, recirculation flow generation, and flow separation). The single-piece design ensures hermetic sealing and operational reliability in sensitive applications.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple components are assembled to form the rotor, then complex functions can be realized, but the manufacturing process becomes more complex and time-consuming

Engineering Contradiction:
Improvefunctional complexityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple functional elements (blades, separating element, relief openings) into a single injection-molded rotor component. This approach simplifies the manufacturing process by eliminating sequential assembly steps, welding operations, and quality control checks for joints. The single-shot or multi-shot injection molding process produces the complete functional assembly in one manufacturing cycle, reducing both complexity and production time.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If welded joints are used to assemble rotor components, then complex rotor functions can be achieved, but the risk of contamination increases due to potential leaks

Engineering Contradiction:
Improvefunctional complexityVSAvoidcontamination risk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates welded joints entirely by combining all rotor functional elements into a single hermetically sealed injection-molded component. This merging creates a leak-free structure that prevents contamination of the pumped fluid, which is critical in sensitive applications such as semiconductor manufacturing, pharmaceutical processing, and chemical handling where fluid purity must be maintained.

Inventive Principle:
Principle #5Merging (Combining)

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 single-piece design simplifies manufacturing, enhances operational reliability, and reduces the risk of contamination, making it suitable for sensitive applications by ensuring high precision and dimensional accuracy without complex assembly processes.

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 around a target axis defined by the axial direction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

This field also exerts an adjustable lateral force on the rotor, allowing its radial position to be actively controlled

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 3

the rotor is passively magnetically supported and stabilized by reluctance forces

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP4644702A1Pump unit for a centrifugal pump and centrifugal pump
Publication Date: 2025.11.05 LEVITRONIX GMBH(CH)
  • EP4644702A1 patent drawingFigure 1~2
  • EP4644702A1 patent drawingFigure 3~4
  • EP4644702A1 patent drawingFigure 5~6

AI summary

A pump unit for a centrifugal pump is proposed, comprising the pump unit and a stator (100) extending in an axial direction (A) from a first axial end (110) to a second axial end (120), wherein a cup-shaped recess is provided at the first axial end (110) into which the pump unit (1) can be inserted, wherein the pump unit (1) has a pump housing (2) with an inlet (21) and an outlet (22) for a fluid to be pumped, and a rotor (10) arranged in the pump housing (2) with a plurality of vanes (103) for pumping the fluid, wherein the rotor (10) is rotatable about the axial direction (A), wherein the pump unit (1) is designed for a contactless magnetic bearing of the rotor (10) and for a contactless magnetic drive of the rotor (10) by the stator (100).wherein the blades (103) of the rotor (10) are arranged around a central inlet region (25) of the rotor (10), wherein the rotor (10) comprises at least one relief opening (104, 104a) for generating a recirculation flow (RF) directed from a rear side of the rotor (10) facing away from the inlet (21) towards the central inlet region (25) of the rotor (10), and wherein the rotor (10) further comprises a separating element (7) arranged in the central inlet region (25) which deflects the recirculation flow (RF) in a radial direction perpendicular to the axial direction (A). The plurality of blades (103), the separating element (7) and the at least one relief opening (104, 104a) of the rotor (10) are designed as a single-piece unit. Furthermore, a centrifugal pump for conveying a fluid is proposed, comprising such a pump unit (1).