Pressure-Controlled Filling of Blood Treatment Membrane Filters

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Solution Overview

Problem

Current methods for filling membrane filters in blood treatment systems are not reliable, leading to potential air entrapment and incomplete filling, which can affect the effectiveness of the treatment process.

Innovation Solution

A method involving pressure-controlled filling of the membrane filter's chambers, where the pump is activated based on measured pressures in the partial circuits to ensure reliable filling and prevent air entrapment, using a blood treatment machine with pressure sensors to manage the filling process and maintain optimal transmembrane pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the first chamber of the membrane filter is filled via the first partial circuit with liquid while the second chamber is still filled with air, then the filling process can be simplified, but air pockets may remain trapped in the membrane filter leading to incomplete filling

Engineering Contradiction:
Improvefilling process simplicityVSAvoidfilling completeness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by first filling the first chamber with liquid before introducing liquid to the second chamber. This sequential approach allows air to be gradually displaced from the first chamber through the membrane into the second chamber, preventing air pocket entrapment and ensuring complete filling while maintaining process simplicity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The membrane acts as an intermediary between the first and second chambers. It allows air to pass from the first chamber to the second chamber while preventing liquid leakage, enabling reliable filling by mediating the air displacement process without compromising filling completeness

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If air is displaced from the first subcircuit into the second subcircuit during filling, then air entrapment is reduced, but the filling process becomes more complex

Engineering Contradiction:
Improveair pocket removalVSAvoidfilling process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses self-service by utilizing the existing membrane structure to automatically facilitate air displacement from the first chamber to the second chamber during the filling process. The membrane's inherent permeability to air allows air pockets to be removed without additional complex mechanisms, maintaining reliability while avoiding excessive complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The filling process is designed to first fill the first chamber completely, allowing air to be displaced into the second chamber before filling the second chamber. This preliminary action sequence ensures air pocket removal while keeping the overall process manageable and not excessively complex

Inventive Principle:
Principle #10Preliminary action

3Reliability

If pressure control is implemented during filling to prevent air entrapment, then filling reliability is improved, but the system complexity increases

Engineering Contradiction:
Improvefilling reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by using pressure sensors to monitor pressure in the first and second chambers during filling and adjusting the filling process accordingly. This feedback mechanism ensures reliable filling by preventing air entrapment through real-time pressure monitoring and control, while the automated control minimizes the perceived complexity for the operator

Inventive Principle:
Principle #23Feedback

4Reliability

If the pump is controlled based on pressure measurements, then air entrapment is prevented and filling is more reliable, but the control system becomes more complex

Engineering Contradiction:
Improvefilling reliabilityVSAvoidpump control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pump control system uses feedback from pressure sensors to automatically adjust filling operations. When pressure differential indicates air entrapment risk, the control system modifies pump operation accordingly. This feedback-based control improves filling reliability while the automation reduces operational complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes operational parameters (pump speed, filling rate) based on pressure measurements. By dynamically adjusting these parameters according to real-time pressure data, the system prevents air entrapment and ensures reliable filling without requiring complex manual intervention

Inventive Principle:
Principle #35Parameter changes

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 ensures reliable and complete filling of the membrane filter chambers, reducing air entrapment and maintaining effective transmembrane pressure, thereby enhancing the efficiency and safety of the blood treatment process.

Implementation Method 1

a membrane filter, in particular a hollow fiber membrane filter, with a first and a second chamber which are semipermeably separated by a membrane

Methodology Applied
Scientific EffectSemipermeable membrane separation: Semipermeable Membrane

Implementation Method 2

the control of the pump for filling the first chamber of the membrane filter via the first sub-circuit takes place depending on a pressure measured in the first sub-circuit and/or the transmembrane pressure

Methodology Applied
Scientific EffectPressure-driven fluid flow: Pressure Gradient

Data Source

PatentEP3914317B1Method for filling a membrane filter
Publication Date: 2024.11.06 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP3914317B1 patent drawingFigure 1
  • EP3914317B1 patent drawingFigure 2
  • EP3914317B1 patent drawingFigure 3

AI summary

The present invention relates to a method for filling a membrane filter of a blood treatment system, the blood treatment system comprising at least one blood treatment machine, a membrane filter, in particular a hollow fibre membrane filter, having a first and a second chamber which are semi-permeably separated by a membrane, and at least one first partial circuit and at least one second partial circuit. The first chamber of the membrane filter is arranged in the first partial circuit and the second chamber of the membrane filter is arranged in the second partial circuit. The first chamber of the membrane filter is filled with liquid via the first partial circuit, whilst the second chamber is still filled with air, and a pump is arranged in the first partial circuit upstream of the membrane filter. According to the invention, the pump for filling the first chamber of the membrane filter via the first partial circuit is controlled according to a measured pressure in the first partial circuit and a measured pressure in the second partial circuit.