Dialyzer Housing with Variable Cross-Section for Internal Filtration
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Solution Overview
Problem
Conventional dialyzers face challenges in achieving high ultrafiltration rates without increasing manufacturing costs and complexity, particularly in effectively removing middle molecules, which is crucial for patient outcomes but requires convective transport that is costly and difficult to implement.
Innovation Solution
A dialyzer design incorporating a volume-increasing filler, such as a water-swellable polymer or polymer foam, that expands within the dialyzer housing to create a pressure gradient, enhancing internal filtration without additional equipment, allowing for improved convective transport and middle molecule removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional dialyzer designs with constant cross-section are used, then manufacturing is simple, but internal filtration and convective transport are insufficient for effective middle molecule removal
Solution Approach 1:
The dialyzer is divided into multiple sections with different cross-sectional areas. The housing includes a first section with a first cross-sectional area and a second section with a second cross-sectional area that is smaller than the first. This segmentation allows different regions to perform different functions: the larger first section accommodates the fiber bundle with adequate spacing, while the smaller second section creates the pressure gradient necessary for enhanced convective transport and internal filtration.
Solution Approach 2:
The invention transitions from a uniform cross-sectional design to a variable cross-sectional design along the longitudinal axis of the dialyzer. By changing the cross-sectional area in the longitudinal dimension, the patent creates a pressure gradient that drives convective flow without requiring additional equipment or complex manufacturing processes.
2Productivity
If hemodiafiltration with reinfusion is used to achieve high convective transport, then middle molecule removal is effective, but equipment complexity and costs increase
Solution Approach 1:
The dialyzer housing itself generates the pressure gradient needed for convective transport through its variable cross-sectional geometry. The narrowing from the first section to the second section creates a pressure drop that drives ultrafiltration and convective flow internally. This self-generating mechanism eliminates the need for external reinfusion systems, substitution fluid tanks, or complex control equipment, thereby reducing device complexity while maintaining effective middle molecule removal.
Solution Approach 2:
The variable cross-sectional housing acts as an intermediary structure that translates the blood flow through a geometric constraint to generate the necessary pressure gradient. This passive geometric mediator replaces the need for active mechanical or electronic systems used in conventional hemodiafiltration with reinfusion.
3Ease of manufacture
If the dialyzer housing cross-section remains constant, then manufacturing is straightforward, but packing density and filtration efficiency are limited
Solution Approach 1:
The dialyzer housing employs a dynamic cross-sectional profile rather than a static uniform design. The cross-sectional area varies along the longitudinal axis, creating zones of different packing densities. The first section has a larger area that allows for optimal fiber bundle placement and spacing, while the second section narrows to increase the velocity and pressure gradient, enhancing filtration efficiency without compromising manufacturability.
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 approach simplifies dialyzer production, increases packing density, and achieves a dialysis effect comparable to hemodiafiltration with reinfusion, improving the clearance of middle molecules and overall dialysis performance without increased material costs or manufacturing complexity.
Implementation Method 1
A dialyzer design incorporating a volume-increasing filler, such as a water-swellable polymer or polymer foam, that expands within the dialyzer housing
Implementation Method 2
This is achieved through a process called ultrafiltration, in which fluid is removed from the blood using a dialyzer
Implementation Method 3
Hemodialysis operates on the principle of equalizing the concentrations of small molecules in two fluids separated by a semipermeable membrane (osmosis)
Implementation Method 4
Hemodialysis operates on the principle of equalizing the concentrations of small molecules in two fluids separated by a semipermeable membrane (osmosis)
Data Source
Figure 1(a)~2
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AI summary
The invention relates to a dialyzer and a method for manufacturing such a dialyzer, wherein the dialyzer has a tubular dialyzer housing (30) in the interior of which a plurality of capillaries (10) extending in the longitudinal direction of the dialyzer housing (30) and arranged transversely to the longitudinal direction are arranged next to each other, wherein a filler (20) with volume-enlarging properties is arranged between the inner wall of the dialyzer housing (30) and the capillaries (10).