Hemodiafiltration Filter Integrity Testing via Transmembrane Pressure
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Solution Overview
Problem
Existing filter testing methods for extracorporeal blood treatment systems, such as hemodialysis and hemodiafiltration, often require high pressures and are not precise enough to detect minor issues like membrane breakages or leaks, and cannot differentiate between membrane faults and hydraulic circuit leaks.
Innovation Solution
A process that generates a transmembrane pressure by creating overpressure on one side of the membrane and depression on the other, using two actuators to monitor gas and liquid flow independently, allowing for precise verification without high hydraulic pressures and distinguishing between membrane and circuit issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high pressures are used in existing filter testing methods, then the testing can be performed, but the precision to detect minor faults like membrane breakages or leaks is insufficient
Solution Approach 1:
The testing system is divided into two independent actuators: one applying overpressure to the first side of the membrane and another creating depression on the second side. This segmentation allows independent control and measurement of pressure differential across the membrane, enabling detection of minor faults without requiring excessively high hydraulic pressures. The segmented approach distributes the testing function across multiple lower-intensity actions rather than one high-intensity action.
Solution Approach 2:
The invention changes the pressure parameters by simultaneously applying overpressure on one side and depression on the other side of the membrane, creating a controlled pressure differential. This parameter change enables the system to detect minor faults with higher precision while maintaining safe hydraulic pressure levels, as the pressure differential is achieved through coordinated action of two actuators rather than excessive pressure from a single source.
2Loss of information
If existing testing methods are used, then filter testing can be performed, but the ability to differentiate between membrane faults and hydraulic circuit leaks is lost
Solution Approach 1:
The system incorporates flow meters on both the first and second sides of the membrane to provide feedback information about fluid flow directions and quantities. This feedback mechanism enables the system to differentiate between membrane faults and hydraulic circuit leaks by analyzing the pattern of flow information from both sides, while the overall system remains relatively simple through the use of standard sensing components.
Solution Approach 2:
The membrane itself serves as an intermediary element that separates the first and second sides of the filter, allowing independent pressure application and flow measurement on each side. This intermediary structure enables the system to isolate and identify the location of faults (membrane versus circuit) without requiring complex diagnostic equipment, as the membrane's physical presence provides natural separation for measurement purposes.
3Reliability
If high hydraulic pressures are used for testing, then the test can be conducted, but the safety and efficiency of the testing process are compromised
Solution Approach 1:
The testing function is segmented into two independent actuators working at lower pressure levels rather than one actuator operating at high pressure. This segmentation improves safety by avoiding excessive hydraulic pressures while maintaining testing efficiency through the coordinated action of both actuators creating the necessary pressure differential across the membrane.
Solution Approach 2:
The invention utilizes pneumatic and hydraulic principles by applying overpressure and depression to create a controlled pressure differential across the membrane. This approach enables efficient testing without requiring extremely high hydraulic pressures, as the pressure differential is achieved through the interaction of two fluid-driven actuators working in coordination, thereby improving both safety and efficiency.
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 method provides a reliable, precise, and economical way to test filters, capable of detecting minor faults and identifying faulty membranes or circuit leaks, while maintaining a safe and efficient testing process for extracorporeal blood treatment systems.
Implementation Method 1
generating a transmembrane pressure of the filter to be tested by creating an overpressure on one side of the membrane and a depression on the opposite side
Implementation Method 2
the gas that passes by diffusion through the membrane is collected in a graduated container
Implementation Method 3
causing the liquid to pass through a semi-permeable membrane able to filter the germs
Implementation Method 4
a first side of the membrane is gradually pressurised with the gas; the gas that passes by diffusion through the membrane
Data Source
AI summary
In a process for testing filters (4) and (13) of treatment fluid of a hemodiafiltration apparatus (1), each filter has a wet semipermeable membrane (5, 14) which separates a gas-filled first chamber (6 and 15) from a liquid-filled second chamber (7 and 16). The first chambers are pressurised by a pump (19) supplying air, while the second chambers are placed in depression by a drainage pump (17) of used dialysis fluid. A first closed system is formed which includes the first chambers and a second closed system is formed which includes the second chambers. Two pressure gauges (P1 and P2) monitor the pressure in the two closed systems for a predetermined time. The monitoring provides indications relating to the filter integrity.