Diaphragm Pump Pressure Sensing for Compressibility Correction
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Solution Overview
Problem
Existing diaphragm pumps in medical applications, such as dialysis, face inaccuracies in fluid measurement due to air accumulation, diaphragm compressibility, and flexibility of hoses and disposable components, which are not adequately addressed by existing methods.
Innovation Solution
A diaphragm pump drive equipped with a pressure sensor and controller that determines basic compressibility by measuring fluid in the pump chamber, accounting for diaphragm flexibility and disposable article flexibility, using regression analysis to correct for varying chamber volumes and air content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piston-cylinder unit is used to hydraulically drive the diaphragm pump, then the pump pressure can be controlled and fluid displacement can be measured, but air accumulations in the pump chamber cause measurement errors and the basic compressibility of the system leads to deviations between drive chamber volume change and actual fluid displacement
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual position of the diaphragm in the pump chamber and comparing it with the position of the piston in the piston-cylinder unit. This feedback loop allows the system to detect deviations caused by air accumulations and basic compressibility, and to correct the measurements accordingly, thereby improving both measurement precision and reliability
Solution Approach 2:
The patent replaces direct mechanical coupling between the piston-cylinder unit and the diaphragm pump with a measurement and evaluation system. Instead of relying solely on mechanical position correspondence, the system uses sensors to measure actual diaphragm position and employs an evaluation unit to calculate corrections based on measured deviations, substituting mechanical assumption with active measurement and computational correction
2Measurement precision
If a fixed compressibility constant is used to correct for system compressibility, then the air content in pumped fluid can be determined, but the basic compressibility changes during operation due to air accumulation in hydraulic fluid and flexibility of hoses and disposable components
Solution Approach 1:
The patent transitions from a static, fixed compressibility constant to a dynamic, adaptive compressibility value. The system continuously measures the actual diaphragm position during operation and updates the compressibility correction factor based on observed deviations, allowing the compressibility value to adapt to changing conditions such as air accumulation in hydraulic fluid and flexibility effects of hoses and disposable components
Solution Approach 2:
The patent performs preliminary measurements during system operation to determine the actual basic compressibility under current operating conditions. By measuring diaphragm position and comparing it with expected position from piston movement, the system预先 determines the appropriate compressibility correction factor before using it for air content calculations, ensuring accurate measurements despite changing system characteristics
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
Enables precise determination of compressibility and air content, improving fluid measurement accuracy and safety in medical applications by correcting for system compressibility and air volume, reducing errors and enhancing patient safety.
Implementation Method 1
the diaphragm pump drive comprises at least one pressure sensor and a controller, wherein the controller controls the diaphragm pump drive and evaluates measured values from the pressure sensor
Implementation Method 2
fluid can be pushed out of the pump chamber by pressing the diaphragm into the pump chamber, and fluid can be suctioned into the pump chamber by pulling the diaphragm out from the pump chamber
Implementation Method 3
the controller is configured to determine a basic compressibility value for the diaphragm pump
Data Source
AI summary
The present invention discloses a diaphragm pump drive for driving the pump chamber of a diaphragm pump, said pump drive comprising at least one pressure sensor and comprising a controller, wherein the controller controls the diaphragm pump drive and evaluates measured values from the pressure sensor, wherein the controller is configured to determine a basic compressibility value for the diaphragm pump, wherein the determination of the basic compressibility value is performed on the basis of at least one measurement and preferably a plurality of measurements, during which fluid is located in the pump chamber.