Peristaltic Pump Delivery Rate Correction Using Hose Pressure
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Solution Overview
Problem
Peristaltic pumps in medical technology, particularly in extracorporeal blood treatment, face challenges in accurately determining and adjusting their delivery rate due to factors like hose pipe deformation and time-dependent changes, which existing methods fail to account for effectively.
Innovation Solution
A method and device that calculate the effective delivery rate of a peristaltic pump by considering the nominal speed, pressure in the hose pipe, and running time, using correction functions to adjust the speed and ensure accurate matching of the delivery rate to the desired rate, incorporating polynomial equations and real-time calculations or stored data for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the delivery rate is adjusted based only on nominal speed and pressure, then the control is simple, but the delivery rate accuracy deteriorates due to hose deformation and time-dependent changes
Solution Approach 1:
The system performs preliminary characterization of the hose pipe by measuring delivery rate at different pressures and running times before actual operation. These measurements are stored as lookup tables or correction factors that enable accurate delivery rate determination during operation without complex real-time calculations, thus achieving high accuracy while maintaining simple control during operation
Solution Approach 2:
The patent introduces intermediate parameters (effective stroke volume, correction factors) that mediate between the easily measurable nominal speed and the difficult-to-measure actual delivery rate. These intermediaries account for hose deformation and time-dependent effects, enabling accurate delivery rate calculation from simple speed measurements
2Productivity
If the pump operates continuously without calibration, then productivity is high, but delivery rate accuracy deteriorates due to hose properties changing over time
Solution Approach 1:
The system performs preliminary characterization of the hose pipe by measuring delivery rate at different pressures and running times before actual operation. These measurements are stored as lookup tables or correction factors that enable accurate delivery rate determination during operation without complex real-time calculations, thus achieving high accuracy while maintaining simple control during operation
Solution Approach 2:
The system continuously monitors pressure and running time, and uses these feedback signals to adjust the effective stroke volume calculation. This feedback mechanism compensates for time-dependent hose deformation and pressure effects, maintaining accurate delivery rate control during continuous operation without requiring frequent recalibration
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 enables precise determination and adjustment of the delivery rate, ensuring accurate liquid delivery in medical applications, even as hose properties change over time, thereby enhancing the reliability of peristaltic pumps in medical treatments.
Implementation Method 1
peristaltic or occluding pumps may be used for reasons of sterility. Various designs of peristaltic pump are known, one of which is the roller pump. All peristaltic pumps have in common the fact that an elastic hose pipe is inserted into the pump, in which the liquid to be delivered flows.
Implementation Method 2
The properties of the hose pipe represent one of the main factors from which the delivery rate of a peristaltic pump depends. It has been shown in practice that a deformation of the elastic hose leads to a change in the delivery rate of the pump.
Implementation Method 3
the pressure in the hose pipe upstream of the pump is measured, in order to be able to predict the pressure upstream of the pump in the course of the treatment
Data Source
AI summary
A method and a device for determining the effective delivery rate of a peristaltic pump with which a liquid is delivered inside an elastic hose pipe or for adjusting the speed of a peristaltic pump in order to match the effective delivery rate of the pump to the desired delivery rate may be characterized in that the effective delivery rate is calculated based on the nominal speed of the pump and the pressure inside the hose pipe upstream of the pump depending on the running time of the pump. The stroke volume of the pump may be multiplied by the nominal speed of the pump and the product from the stroke volume and the speed of the pump may be corrected by a correction function, thereby determining the effective delivery rate of the pump.