Blood Separation Pump Stroke Calibration
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Solution Overview
Problem
Existing blood separation systems face challenges in accurately controlling fluid flow rates and volumes due to variations in tubing, mounting conditions, and biological fluid characteristics, which can affect the efficiency and safety of the separation process.
Innovation Solution
A method for calibrating pump stroke volumes during blood separation procedures by determining the variance between predetermined and actual flow rates, adjusting the flow rate for subsequent procedure states, and limiting the recalibration adjustment to prevent excessive changes, ensuring precise fluid management throughout the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pump flow rates are controlled based on predetermined values, then the blood separation procedure can be performed, but flow rate variations occur due to tubing, mounting, and fluid characteristic changes
Solution Approach 1:
The system implements feedback control by continuously monitoring actual flow rates through weight measurements and comparing them to predetermined flow rates. The controller automatically adjusts pump stroke volumes based on the variance between actual and predetermined values, creating a closed-loop control system that maintains flow rate consistency despite variations in tubing, mounting conditions, or fluid characteristics.
Solution Approach 2:
The system dynamically changes pump operating parameters (stroke volume, stroke rate) based on real-time conditions. By adjusting these parameters in response to measured flow rate variances, the system adapts to changing conditions such as different tubing configurations, mounting variations, and blood viscosity changes, thereby maintaining reliable flow control.
2Productivity
If pump stroke volume is increased to improve processing speed, then productivity increases, but flow rate accuracy decreases due to variations in system conditions
Solution Approach 1:
The feedback mechanism continuously monitors actual flow rates and adjusts pump stroke volumes to compensate for inaccuracies. This allows the system to maintain high processing speeds while correcting for flow rate deviations caused by system variations, thereby preserving both productivity and measurement accuracy.
Solution Approach 2:
The system performs preliminary calibration by measuring actual flow rates during initial operation and establishing correction factors before full-speed processing begins. This preliminary adjustment ensures that subsequent high-speed operation maintains accurate flow rate control.
3Measurement precision
If frequent pump recalibration is performed to maintain flow rate accuracy, then measurement precision improves, but procedure time increases
Solution Approach 1:
The continuous feedback mechanism allows the system to maintain flow rate accuracy during ongoing procedures without requiring frequent stopping for recalibration. By making real-time adjustments based on weight measurements, the system preserves measurement precision while minimizing interruption to the blood separation process.
Solution Approach 2:
The system maintains continuous flow rate monitoring and adjustment throughout the procedure, eliminating the need to stop the blood separation process for recalibration. This continuous operation preserves both measurement precision and procedural efficiency by keeping the useful action uninterrupted.
4Reliability
If pump flow rates are adjusted to compensate for system variations, then flow rate consistency improves, but device complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The system uses weight measurements as an intermediary parameter to indirectly measure and control flow rates. Rather than directly measuring complex flow characteristics, the system uses simple weight changes of reservoirs to infer flow rate information, which simplifies the sensing mechanism while maintaining reliable flow control.
Solution Approach 2:
The system performs self-calibration by automatically comparing measured flow rates to predetermined values and adjusting pump parameters without external intervention. This self-service capability maintains flow rate consistency while minimizing the need for complex external control systems or manual calibration procedures.
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 safe and efficient blood separation by maintaining consistent fluid flow, reducing the risk of procedural errors and improving the overall efficiency of the blood processing system.
Implementation Method 1
fluid is flowed to or from a reservoir by action of the pump
Data Source
AI summary
A method is provided for calibrating a pump during a blood separation procedure that has at least a first and second state or phase where fluid is flowed to or from a reservoir by action of the pump. The state or phase of the procedure may be a priming state, a draw state, a separation state and a return state, and the pump calibration may be performed between consecutive performances of the same procedure state. The calibration is based on a variance between the volume of fluid predicted to be processed by the pump for the given state of the procedure and the actual volume processed based on the change of weight of the reservoir. Recalibration of the pump, if necessary, is accomplished before the performance of the second phase is commenced.