Post-Filter Container Volume Restriction for Automatic Air Purging

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Solution Overview

Problem

Existing leukoreduction systems fail to efficiently remove air from the post-filter container, especially during filtration of smaller amounts of fluid, leading to incomplete filtration and reduced quality of filtered blood due to manual dependency and pressure differential limitations.

Innovation Solution

A biological fluid filtration system with a pre-filter container, a filter, and an expandable post-filter container, where the post-filter container's expansion is restrained by a volume restriction, allowing automatic air removal through a bypass line and one-way valve, eliminating the need for manual 'burping' and ensuring complete drainage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual burping is used to remove air from the post-filter container, then air removal is achieved, but the process is user-dependent and incomplete for smaller fluid volumes

Engineering Contradiction:
Improveair removal operationVSAvoidcomplete filtration
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system automatically removes air from the post-filter container using a one-way valve and bypass line configuration. The air is purged automatically during the filtration process without requiring manual intervention, making the system self-service and eliminating user dependency for complete air removal.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The air removal function is separated from the main filtration path by introducing a bypass line with a one-way valve. This segmentation allows air to be removed through a dedicated pathway while the main filtration process continues uninterrupted, ensuring both functions are performed effectively.

Inventive Principle:
Principle #1Segmentation

2Productivity

If pressure differentials are relied upon for air removal, then filtration occurs, but air removal is insufficient for smaller fluid amounts

Engineering Contradiction:
Improvefiltration efficiencyVSAvoidfluid volume
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

A one-way valve is introduced as an intermediary component in the bypass line. This valve acts as a mediator that selectively allows air to pass from the post-filter container to the pre-filter container while preventing fluid leakage, enabling effective air removal regardless of the fluid volume being filtered.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adapts to different fluid volumes by using the one-way valve mechanism. For smaller fluid amounts where pressure differentials are insufficient, the valve opens to allow air removal through the bypass line, while for larger volumes the normal pressure differential suffices and the valve remains closed, maintaining filtration efficiency across varying quantities.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If air is not removed from the post-filter container, then filtration structure is simple, but air aggregation prevents complete filtration and reduces blood quality

Engineering Contradiction:
Improvefiltration system structureVSAvoidfiltration completeness
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The air removal function is extracted from the main filtration body by introducing a separate bypass line with a one-way valve. This extraction allows air to be removed through a dedicated pathway without complicating the core filtration structure, maintaining simplicity while achieving complete filtration.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If bypass line is added for air removal, then air can be purged, but system complexity increases

Engineering Contradiction:
Improveair removal effectivenessVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The air removal function is segmented into a separate bypass line with a one-way valve, distinct from the main filtration path. This segmentation allows air to be removed through a dedicated pathway without complicating the core filtration structure, maintaining simplicity while achieving complete filtration.

Inventive Principle:
Principle #1Segmentation

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 system efficiently removes air from the post-filter container, ensuring complete filtration and improved blood quality by automatically purging air, even during filtration of smaller volumes, thereby enhancing the filtration process and reducing user dependency.

Implementation Method 1

a one-way valve allowing flow from the post-filter container to the pre-filter container

Methodology Applied
Scientific EffectOne-way valve flow control: Valve

Implementation Method 2

the post-filter container's expansion is restrained by a volume restriction

Methodology Applied
Scientific EffectVolume restriction:

Implementation Method 3

filter the blood to remove leukocytes

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP1938850B1Biological fluid filtration systems and methods
Publication Date: 2011.10.19 FENWAL INC
  • EP1938850B1 patent drawingFigure 1A~1D
  • EP1938850B1 patent drawingFigure 2~5
  • EP1938850B1 patent drawingFigure 6A~7D

AI summary

Biological fluid filtration systems and methods are provided for the treatment of air within the system. A filtration system includes a pre-filter container (14) joined to an expandable post-filter container (24) by a filter line (18,22) having a filter (28). The post-filter container includes a volume restriction (12) that limits its expansion upon receipt of a filtered fluid. In use, a fluid is transferred from the pre-filter container, through the filter line and the filter, to the post-filter container. The volume restriction limits the expansion of the post-filter container during filtration, which increases the pressure within the post-filter container, thereby improving removal of air from the post-filter container.