Blood Processing Filter with Layered Filtration Medium
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing blood processing filters face challenges in simultaneously achieving high leukocyte removal capability and reducing filtration time, as methods to enhance leukocyte removal often result in increased pressure loss and longer filtration times.
Innovation Solution
A blood processing filter comprising two types of filter materials with different airflow resistances per unit basis weight, where a coarse filter material is positioned upstream and a dense filter material downstream, with specific airflow resistance ranges and critical wet surface tension values to optimize leukocyte removal and filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fiber diameters are reduced or bulk density is increased to increase surface area of filtration medium, then leukocyte removal capability is enhanced, but pressure loss becomes larger and filtration time increases
Solution Approach 1:
The filtration medium is segmented into multiple layers with different fiber diameters and pore structures. The upstream layer has larger pores for high flow rate, while downstream layers have progressively smaller pores for effective leukocyte removal, dividing the filtration function into stages that resolve the contradiction between removal efficiency and filtration speed
Solution Approach 2:
Different regions of the filtration medium are assigned different local qualities: the upstream region uses coarse fibers with large pores to minimize pressure loss and maintain high flow rate, while downstream regions use fine fibers with small pores to maximize leukocyte adhesion and removal, allowing each region to optimize for its specific function
2Productivity
If surface modification or surface treatment is applied to improve blood wettability, then pressure loss is reduced and filtration time decreases, but leukocyte removal capability deteriorates
Solution Approach 1:
The filtration medium is divided into layers where surface modification is selectively applied only to specific layers rather than uniformly across all layers, allowing hydrophilic treatment to reduce pressure loss in flow-critical regions while leaving other regions with natural surface properties that favor leukocyte adhesion
Solution Approach 2:
Surface treatment is applied locally to specific regions or layers of the filtration medium where blood wettability is most critical for maintaining flow rate, while other regions maintain their original surface characteristics that provide optimal adhesion properties for leukocyte removal, creating spatial variation in surface properties
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 achieves high leukocyte removal performance while significantly reducing filtration time, balancing the need for effective leukocyte capture and efficient blood flow.
Implementation Method 1
a coarse filter material (having a large pore diameter) is positioned at an upstream side of the filtration medium
Implementation Method 2
the mechanism of leukocyte removal by the filter methods is predominantly due to the adhesion or adsorption of leukocytes onto the surface of the filtration medium
Implementation Method 3
the mechanism of leukocyte removal by the filter methods is predominantly due to the adhesion or adsorption of leukocytes onto the surface of the filtration medium
Implementation Method 4
a pressure loss caused by the filtration medium when processing blood becomes larger
Data Source
AI summary
A blood processing filter includes a container having 2 ports respectively functioning as an inlet for a liquid to be processed and as an outlet for the processed liquid, and a filtration medium filled in the container, wherein an airflow resistance of the filtration medium is 55.0 kPa·s/m or more and less than 85.0 kPa·s/m, the filtration medium includes a filter material A having an airflow resistance per unit basis weight of 0.01 kPa·s·m/g or more and less than 0.04 kPa·s·m/g and a filter material B having an airflow resistance per unit basis weight of 0.04 kPa·s·m/g or more, at least a part of the filter material A is disposed on a side closer to the inlet for a liquid to be processed than the filter material B, and a sum of airflow resistances of the filter material A is 6.0 kPa·s/m or more.