Air Access Component Induces Plug Flow in Blood Separation

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Solution Overview

Problem

Existing blood processing systems suffer from dispersion of red blood cells (RBCs) into plasma during separation, leading to reduced collection volume and purity issues due to laminar flow velocity profiles and Taylor dispersion, which is not addressed by current automated systems.

Innovation Solution

The implementation of air-induced plug flow through the use of an air access component in the fluid flow circuit, controlled by a programmable controller, to separate and maintain the integrity of fluid components by creating an interface between RBCs and plasma fractions, preventing mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated blood component separation is used, then processing efficiency is improved, but red blood cell dispersion into plasma occurs due to laminar flow velocity profiles

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidseparation purity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces an air plug as an intermediary substance between the red blood cell fraction and plasma fraction in the tubing. This air plug acts as a physical barrier that prevents direct contact and mixing between the two fluid phases, thereby eliminating Taylor dispersion while allowing continuous automated processing to proceed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If centrifugation is used to separate blood components, then separation speed is improved, but collection volume is reduced due to RBC contamination of plasma

Engineering Contradiction:
Improveseparation speedVSAvoidplasma collection volume
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The air plug serves as a mediator that allows the centrifugation process to continue at high speed without causing RBC contamination. By preventing back-mixing in the tubing, the air plug enables collection of larger plasma volumes that would otherwise be contaminated by dispersed RBCs.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If continuous flow through tubing is used, then processing throughput is improved, but Taylor dispersion causes mixing of RBC and plasma fractions

Engineering Contradiction:
Improveprocessing throughputVSAvoidfraction integrity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The air plug introduced into the continuous flow acts as a stabilizing intermediary that maintains the integrity of separated fractions. It creates distinct interfaces that prevent molecular diffusion and Taylor dispersion, allowing continuous high-throughput processing without compromising fraction composition stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enhances the purity and maximizes the collection volume of separated plasma by ensuring plug flow, reducing contamination and improving the efficiency of blood component separation.

Implementation Method 1

inducing plug flow during fluid separation using air

Methodology Applied
Scientific EffectPlug flow:

Implementation Method 2

Taylor dispersion will occur causing the RBCs to move into, and thus mix with, the upstream plasma fraction

Methodology Applied
Scientific EffectTaylor dispersion: Dispersion (of waves)

Implementation Method 3

manually loading the primary collection container and associated tubing and satellite containers into a centrifuge to separate the whole blood into concentrated red cells and platelet-rich or platelet-poor plasma

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP4233931B1Systems for inducing plug flow during fluid separation using air
Publication Date: 2026.04.08 FENWAL INC
  • EP4233931B1 patent drawingFigure 1~4
  • EP4233931B1 patent drawingFigure 5
  • EP4233931B1 patent drawingFigure 6

AI summary

A fluid separation system and method includes a durable hardware component including a pump station with plurality of pumps, a centrifuge mounting station and drive unit, a plurality of valves and clamps, and a controller. The system includes a single use fluid flow circuit having a separation chamber configured to be received by the centrifuge and the fluid flow circuit is engageable with the durable hardware component to control fluid flow within the fluid flow circuit. The fluid flow circuit having an air access component configured to selectively receive air and to provide the air into a conduit to induce plug flow between the separated fluid component and another separated fluid component, wherein the controller is configured to operate the system to perform one or more blood processing procedures to convey a fluid into the separation chamber and to remove a separated fluid component from the separation chamber.