Defoaming Layer and Mesh Filter for Blood Filtration

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Solution Overview

Problem

Existing filter assemblies for blood filtration in autotransfusion processes face challenges in preventing foam formation and reducing the risk of chemical leaching from antifoam agents.

Innovation Solution

A filter assembly comprising a defoaming layer with an embossed three-dimensional structure and a mesh filter layer, which mechanically entraps foam and prevents its passage, eliminating the need for antifoam agents and associated risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If antifoam agents (PDMS-hydrophobed silica) are used to prevent foam formation, then foam is reduced, but chemical leaching into blood occurs causing emboli risk and postoperative deaths

Engineering Contradiction:

Improvefoam formationVSAvoidchemical leaching and emboli

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent removes the harmful chemical antifoam agents (PDMS-hydrophobed silica) from the blood filtration system and replaces them with a purely mechanical defoaming layer that physically traps foam bubbles without chemical interaction with the blood

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a defoaming layer as an intermediary component between the blood and the filtration system. This layer mechanically captures foam bubbles through its porous structure, preventing them from entering the blood stream while avoiding direct chemical contact with blood components

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If PDMS without silica is used as antifoam agent, then emboli risk is reduced, but chemical leaching still occurs

Engineering Contradiction:

Improvereduction of emboli riskVSAvoidchemical leaching

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the chemical defoaming mechanism (PDMS surfactant action) with a mechanical defoaming mechanism. The defoaming layer uses its physical porous structure and surface tension properties to mechanically trap and remove foam bubbles without relying on chemical surfactants that can leach into the blood

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 filter assembly effectively prevents foam formation in blood and other body fluids, ensuring the quality of filtered fluids by avoiding chemical leaching, thus enhancing the safety and efficacy of autotransfusion processes.

Implementation Method 1

a defoaming layer made of a monofilament woven open mesh fabric and with an embossed three dimensional structure configured for entrapping foam built up in the blood

Methodology Applied

Scientific EffectFoam entrapment: Foam

Implementation Method 2

the second layer is a mesh filter layer, and wherein the mesh filter layer is arranged downstream of the defoaming layer

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP3986501B1Filter assembly and container for collecting a body fluid containing the same

Publication Date: 2025.05.21 FRESENIUS HEMOCARE ITAL

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AI summary

A filter assembly for filtering a body fluid comprising a filter system and a filter holder is disclosed, wherein the filter system consists of at least two layers. The first layer is a defoaming layer made of a monofilament woven open mesh fabric and with an embossed three dimensional structure configured for entrapping foam built up in the body fluid. The second layer is a mesh filter layer, and is arranged downstream of the defoaming layer. A container for collecting a body fluid comprising such a filter assembly is also disclosed.