Asymmetrical Dialyzer Header Cap for Uniform Blood Flow

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Solution Overview

Problem

Existing dialyzers experience issues with non-uniform blood flow distribution, mechanical stress on blood cells, and inefficient osmotic transfer due to pressure differentials and design constraints, leading to reduced efficiency and potential harm to patients.

Innovation Solution

A dialyzer header cap with an asymmetrical, concave shape and specific geometric configurations, such as an asymmetrical elliptic paraboloid, is designed to improve blood flow uniformity, reduce mechanical stress, and enhance osmotic transfer efficiency by minimizing air bubble formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a centrally aligned inlet port is used in existing dialyzers, then the structure is simple and easy to manufacture, but blood flow distribution becomes non-uniform and mechanical stress on blood cells increases

Engineering Contradiction:
Improveinlet port structure simplicityVSAvoidblood flow distribution uniformity
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies asymmetry by positioning the inlet port off-center and designing the header cap with an asymmetrical internal geometry. This asymmetric configuration redistributes blood flow more uniformly across the fiber bundle entrance, reducing non-uniform flow distribution and mechanical stress on blood cells while maintaining manufacturing feasibility.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces dimensional changes by designing the header cap with a specific internal geometry that includes a first region and a second region with different cross-sectional areas. This three-dimensional geometric variation guides blood flow distribution across multiple dimensions, improving uniformity of flow into the fiber bundle.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If pressure differentials are created during blood entry, then blood flow into hollow fibres is driven, but mechanical stress on blood and blood cells increases and flow efficiency is impaired

Engineering Contradiction:
Improveblood flow into hollow fibresVSAvoidmechanical stress on blood cells
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by designing the header cap with a gradual transition geometry between regions of different cross-sectional areas. This gradual transition cushions the blood flow against sudden pressure changes, reducing mechanical stress on blood cells while maintaining adequate flow velocity into the hollow fibres.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs curvature principles by designing the header cap internal surface with smooth curved transitions rather than sharp angles. This curved geometry reduces turbulence and mechanical stress on blood cells while maintaining efficient blood flow distribution into the fiber bundle.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Productivity

If the header cap geometry is optimized for uniform blood distribution, then blood flow uniformity improves, but device complexity increases

Engineering Contradiction:
Improveblood flow distribution uniformityVSAvoidheader cap geometry complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by designing the header cap with different geometric characteristics in different regions. The first region has a larger cross-sectional area to receive blood flow, while the second region has a smaller cross-sectional area to distribute flow uniformly into the fiber bundle. This localized geometric variation achieves flow uniformity without requiring complex overall device architecture.

Inventive Principle:
Principle #3Local quality

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 new header cap design achieves a 30-35% improvement in blood flow distribution uniformity, reduces mechanical stress by 12% or more, and decreases air bubble formation by 30-35%, thereby enhancing overall dialysis efficiency and patient safety.

Implementation Method 1

the structure of the header cap of the dialyzer can play a significant role in determining how blood flow in the dialyser is managed

Methodology Applied
Scientific EffectFluid flow distribution:

Implementation Method 2

Low molecular weight metabolites, such as urea, pass from the blood into the dialysate through osmotic action

Methodology Applied
Scientific EffectOsmosis: Osmosis

Data Source

PatentEP3900814B1Dialyzer header cap
Publication Date: 2025.07.30 BELLCO SRL
  • EP3900814B1 patent drawingFigure 3a
  • EP3900814B1 patent drawingFigure 3b
  • EP3900814B1 patent drawingFigure 3c

AI summary

A dialyzer header cap, comprising an asymmetrical curved surface forming a hollow, wherein said hollow comprises an opening which comprises the outlet port, and further comprising an inlet port attached to the curved surface, wherein the inlet port is essentially orthogonal to the outlet.