Medical Membrane Pump Drive Compressibility Determination
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Solution Overview
Problem
Existing methods for determining system compressibility of medical membrane pump drives and air proportion/quantity in medical fluids are inaccurate due to external influences and system compressibility variations, particularly caused by air collection in hydraulic fluids and hose flexibility.
Innovation Solution
A method that involves moving a membrane pump drive to predefined pressure levels while supporting the membrane on a rigid surface to determine system compressibility, using pressure sensors and position sensors to detect operating parameter values, thereby isolating the system compressibility from external influences and ensuring accurate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the system compressibility is determined using existing methods (DE 19919572 A1), then the air proportion in the pumped fluid can be determined, but the measurement accuracy deteriorates due to system compressibility variations caused by air collection in hydraulic fluid and hose flexibility
Solution Approach 1:
The patent applies preliminary action by determining the system compressibility value at the beginning of the pump's operational life before air has accumulated in the hydraulic fluid. This initial measurement serves as a reference value that remains valid throughout operation, eliminating the need for repeated measurements that would be affected by changing system compressibility. The control unit stores this reference value and uses it continuously for air proportion calculations, thereby resolving the contradiction between measurement precision and system reliability.
2Measurement precision
If the membrane is not supported on a rigid surface during measurement, then the pump can operate with flexible components, but the measurement of system compressibility becomes inaccurate due to external influences
Solution Approach 1:
The patent applies segmentation by separating the measurement phase from the operational phase. During the measurement phase, the membrane is supported on a rigid surface to isolate and measure pure system compressibility without external influences. During normal operation, the membrane returns to its flexible state for fluid pumping. This temporal and functional segmentation allows accurate measurement while maintaining operational flexibility, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The rigid surface acts as an intermediary element during the measurement process. It provides a stable reference plane that temporarily supports the membrane, allowing the measurement system to isolate the compressibility of the hydraulic system from other variables. After measurement, the intermediary is removed and normal operation resumes. This intermediary enables accurate measurement without permanently increasing device complexity.
3Duration of action of stationary object
If air collects in the hydraulic fluid during pump operation, then the pump can continue operating, but the system compressibility increases and invalidates previous measurements
Solution Approach 1:
The patent performs the system compressibility measurement at the beginning of operation when the hydraulic system is still free of air bubbles. This preliminary measurement captures the true system compressibility before degradation occurs. The control unit then stores this reference value and uses it throughout the pump's operational life, eliminating the need for repeated measurements that would be affected by air accumulation. This approach allows the pump to operate for extended periods while maintaining measurement validity.
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 provides a more precise determination of system compressibility and air proportion/quantity, reducing measurement errors and improving fluid balancing in medical membrane pumps.
Implementation Method 1
a first and a second pressure level are moved to and a first and second operating parameter value of the membrane pump drive are detected, wherein the system compressibility value is determined on the basis of the detected operating parameter values
Implementation Method 2
a first and a second pressure level are moved to and a first and second operating parameter value of the membrane pump drive are detected
Implementation Method 3
a first and a second pressure level are moved to and a first and second operating parameter value of the membrane pump drive are detected
Implementation Method 4
air that collects in the hydraulic fluid can in particular result in a certain compressibility of the hydraulic system
Implementation Method 5
hoses that connect the piston-in-cylinder unit to the drive chamber can, for example, have a certain flexibility and therefore expand at an elevated pressure
Data Source
AI summary
A method of determining a system compressibility value of a medical membrane pump drive is provided which includes moving to a first and second pressure level and detecting a first and second operating parameter value of the membrane pump drive. The system compressibility value is determined on the basis of the detected operating parameter values and the membrane of the membrane pump drive is supported at a rigid surface during the determination of the system compressibility value.