Axial Actuation for Replacing Magnetically Coupled Pump Units

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Solution Overview

Problem

Centrifugal pumps with contactless, magnetically driven and mounted rotors face challenges in safely and easily replacing the pump unit, especially at high power outputs where strong magnetic forces make manual separation difficult and risky.

Innovation Solution

A device is proposed that allows for the simple, quick, and safe separation of the pump unit from the stator by exerting a mechanical force in the axial direction using an actuating device, such as a piston or a spring element, which reduces the risk of injury and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump unit is locked into the stator using a bayonet lock, then the connection is secure and reliable, but the replacement process becomes time-consuming and labor-intensive

Engineering Contradiction:
Improveconnection reliabilityVSAvoidreplacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The pump unit is pre-loaded onto a loading device with a lifting mechanism before being inserted into the stator. The lifting mechanism is pre-positioned to engage with the pump unit, allowing for rapid insertion and replacement without manual manipulation during the actual connection process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The manual bayonet locking mechanism is replaced with an automated lifting and insertion system. The loading device with lifting mechanism automates the previously manual process of securing the pump unit to the stator, reducing both time and labor requirements while maintaining connection reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Power

If strong permanent magnets are used in the rotor and stator for high power output, then the power output increases, but the magnetic forces make manual separation of the pump unit difficult and dangerous

Engineering Contradiction:
Improvepower outputVSAvoidease of pump unit separation
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The manual separation process is replaced with an automated lifting mechanism that uses mechanical force to overcome the strong magnetic attraction between the rotor and stator. The loading device with lifting mechanism safely extracts the pump unit from the stator without requiring manual intervention, eliminating the danger associated with strong magnetic forces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The loading device acts as an intermediary between the operator and the pump unit. Instead of directly handling the pump unit against strong magnetic forces, the operator controls the loading device which then performs the separation action, reducing the risk of injury while maintaining high power output capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the pump unit is designed as a disposable single-use part, then sterilization complexity is reduced, but the frequency of replacement increases leading to higher operational time loss

Engineering Contradiction:
Improvesterilization simplicityVSAvoidreplacement frequency
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The pump unit is pre-loaded onto the loading device in advance, before the actual pumping operation begins. This preliminary loading allows the replacement process to be executed rapidly when needed, minimizing operational downtime despite the single-use nature of the pump unit.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The replacement process is automated using the lifting mechanism and loading device, transforming a potentially time-consuming manual operation into a rapid automated process. This reduces the time penalty associated with frequent replacements of disposable pump units.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 device enables rapid and safe replacement of the pump unit, reducing the risk of injury to operating personnel and protecting the pump components, while also facilitating quick exchanges, especially in applications where the pump unit is designed as a disposable part.

Implementation Method 1

The stator's electrical windings can be used to generate a magnetic rotating field which, on the one hand, exerts a torque on the rotor, causing it to rotate about a desired axis of rotation defined by the axial direction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

exerts an arbitrarily adjustable transverse force on the rotor, allowing its radial position to be actively controlled or regulated

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 3

the rotor is passively magnetic, meaning it cannot be controlled; it is supported or stabilized by reluctance forces

Methodology Applied
Scientific EffectReluctance forces: Magnetic Reluctance

Implementation Method 4

an actuating device with which a mechanical force can be exerted on the pump unit, wherein the mechanical force acts in the axial direction and is directed such that it separates the pump unit from the stator in the axial direction

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP4567282A1Device for changing a pump unit of a centrifugal pump and centrifugal pump
Publication Date: 2025.06.11 LEVITRONIX GMBH(CH)
  • EP4567282A1 patent drawingFigure 1a
  • EP4567282A1 patent drawingFigure 1b~2
  • EP4567282A1 patent drawingFigure 3

AI summary

A device is proposed for changing a pump unit (50) of a centrifugal pump (200), which comprises the pump unit (50) and a stator (100) which extends in an axial direction (A) from a first axial end (101) to a second axial end (102), wherein a cup-shaped recess (121) is provided at the first axial end (101), into which the pump unit (50) can be inserted, wherein the pump unit (50) comprises a pump housing (52) with a cup (531) which can be inserted into the cup-shaped recess (121) of the stator (100), wherein a rotor (51) for conveying a fluid is arranged in the pump housing (52), which rotor has a magnetically active core (511), wherein the rotor (51) is rotatable about the axial direction (A), and wherein the stator (100) is designed for a contactless magnetic drive and a contactless magnetic bearing of the rotor (51),wherein the rotor (51) is passively magnetically stabilized relative to the stator at least in the axial direction (A). The device comprises an actuating device (6) with which a mechanical force can be exerted on the pump unit (50), wherein the mechanical force acts in the axial direction (A) and is directed such that it separates the pump unit (50) from the stator (100) in the axial direction (A). Furthermore, a centrifugal pump for conveying a fluid is proposed, which comprises such a device.