Continuous-Flow Centrifuge Guide Contour to Reduce Line Stress

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Solution Overview

Problem

Conventional flow-through centrifuges experience short service life of connecting lines due to high stresses, leading to frequent replacements and downtime, despite attempts to extend the life through speed reduction or material reinforcement.

Innovation Solution

A compensating rotor guide device with a guide contour design that varies the radius of curvature to reduce alternating stresses on the connecting line, using a larger radius near the rotor axis and smaller radius further away, thereby minimizing material strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the rotor speed is reduced to decrease stresses on the connecting line, then the service life of the connecting line is extended, but the productivity of the centrifuge decreases

Engineering Contradiction:
Improveservice life of connecting lineVSAvoidproductivity of centrifuge
Core Design Contradiction:
Duration of action of moving objectVSProductivity

Solution Approach 1:

The patent changes the geometric parameter of the guide contour (radius of curvature) to reduce alternating stresses on the connecting line. By optimizing the radius of curvature in different sections, the design allows the connecting line to withstand higher operational stresses without failure, enabling the centrifuge to operate at higher speeds for improved productivity while maintaining extended service life of the connecting line.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If the connecting line is made with reinforced material to increase strength, then the service life is extended, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveservice life of connecting lineVSAvoiddevice complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent converts the harmful alternating stresses into a manageable design parameter by optimizing the guide contour geometry. Instead of fighting the stresses through material reinforcement, the design uses the natural stress distribution to inform the geometric optimization, allowing standard materials to achieve extended service life through intelligent design rather than complex reinforced structures.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent optimizes geometric parameters (radius of curvature) of the guide contour to reduce stress concentrations. This approach extends the service life of the connecting line using design optimization rather than material reinforcement, avoiding increased device complexity and manufacturing costs associated with reinforced materials.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If frequent replacements of the connecting line are performed to maintain reliability, then the operational reliability is maintained, but the loss of time due to downtime increases

Engineering Contradiction:
Improveoperational reliabilityVSAvoiddowntime for replacement
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary design optimization of the guide contour geometry to prevent connecting line failure before it occurs. By optimizing the radius of curvature in advance, the design extends the service life of the connecting line, reducing the frequency of replacements and associated downtime while maintaining operational reliability throughout the extended service period.

Inventive Principle:
Principle #10Preliminary action

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 design significantly extends the service life of the connecting line, reducing maintenance frequency and downtime, while maintaining operational efficiency.

Implementation Method 1

The radius of curvature is greater for a first distance from the rotor axis than for a second distance from the rotor axis, wherein the first distance is smaller than the second distance. This design reduces alternating stresses on the connecting line caused by centrifugal forces during rotation.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4321253B1Continuous flow centrifuge and balancing rotor guiding device
Publication Date: 2025.10.01 SARTORIUS STEDIM NORTH AMERICA INC
  • EP4321253B1 patent drawingFigure 1
  • EP4321253B1 patent drawingFigure 2
  • EP4321253B1 patent drawingFigure 3

AI summary

The invention relates to a flow centrifuge with a rotor that has at least one centrifugation chamber and is rotated about a rotor axis (7) at a rotor speed. The flow centrifuge has a connecting section (12) through which connecting lines (16, 17) extend. During operation of the flow centrifuge with a rotating rotor, a medium can be supplied to and discharged from the centrifugation chamber via the connecting lines (16, 17). One end section (18) of the connecting section (12) is fixed to the housing, while the other end section (19) of the connecting section (12) rotates with the rotor. To prevent twisting of the connecting section (12), it is guided in a compensating rotor guide device (20) (in particular a guide tube (21)), which is rotated about the rotor axis (7) at half the rotor speed.According to the invention, the compensating rotor guide device (20) has a guide contour (27) whose radius of curvature (32) in a first guide contour section (28) is larger than the radius of curvature (33) in a second guide contour section (29). This increases the service life of the connecting string (12).