Syringe Pump Plunger Control for Occlusion Mitigation
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Solution Overview
Problem
Syringe pumps face challenges in accurately delivering liquid medications due to issues like slack in the system, which can lead to inconsistent flow rates and potential occlusions, affecting the precision and reliability of medication administration.
Innovation Solution
A method and apparatus for a syringe pump that includes a force sensor to detect changes in force and distance, allowing the pump to adjust its actuation speed and stop when a target volume is reached, while also issuing an alarm for potential occlusions, ensuring accurate delivery and alerting users to any issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the plunger is actuated at a constant high speed to increase productivity, then the delivery speed improves, but slack in the system causes inconsistent flow rates and potential occlusions
Solution Approach 1:
The system dynamically adjusts the plunger actuation speed based on real-time force feedback from the force sensor. Instead of maintaining a constant high speed, the control system modulates the actuation speed to keep the plunger force within a predetermined range, thereby maintaining consistent flow rates while still achieving high productivity when conditions permit.
Solution Approach 2:
The force sensor provides continuous feedback on the plunger force during actuation. The control system uses this feedback to adjust the actuation speed in real-time, preventing occlusions caused by excessive force and ensuring consistent flow rates. This closed-loop control resolves the contradiction by allowing high speeds only when force conditions are appropriate.
2Manufacturing precision
If a force sensor is added to detect force changes and adjust actuation speed, then delivery precision improves, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical flow rate control mechanisms with a simpler force-based control approach. Instead of using complex mechanical linkages to maintain precise flow rates, the invention uses a force sensor to monitor plunger force and adjusts actuation speed accordingly, simplifying the overall control system while achieving high delivery precision.
Solution Approach 2:
The system changes the control parameter from direct flow rate control to force-based control. By monitoring and controlling plunger force rather than directly controlling flow rate, the system achieves precise delivery with a simpler sensor and control algorithm, reducing device complexity while maintaining or improving precision.
3Loss of time
If the plunger actuation speed is increased to reduce therapy time, then treatment efficiency improves, but occlusion risk increases due to slack in the system
Solution Approach 1:
The system performs preliminary detection of slack in the system by monitoring force levels during initial actuation. Before increasing actuation speed to reduce therapy time, the system ensures that slack has been taken up and the system is ready for high-speed operation. This preliminary action prevents occlusions while enabling rapid therapy delivery.
Solution Approach 2:
The system rapidly takes up slack in the early phase of actuation by operating at high speed when force levels indicate the system is ready. Once slack is eliminated, the system maintains high actuation speed to complete therapy quickly, minimizing therapy time while avoiding occlusions through force-based speed modulation.
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
The solution ensures precise and reliable liquid delivery by adjusting actuation speeds based on force and distance measurements, preventing occlusions and maintaining consistent flow rates, thus enhancing the accuracy and safety of medication administration.
Implementation Method 1
a force sensor to detect changes in force and distance
Implementation Method 2
a plunger mounted to a shaft that pushes a liquid out of a reservoir
Data Source
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AI summary
A method for discharging fluid from a syringe and for mitigating occlusion conditions includes actuating the plunger of a syringe into a barrel. The method monitors fluid pressure within the barrel of the syringe and determines that an occlusion exists when the fluid pressure exceeds a predetermined threshold. The method actuates the plunger out of the barrel by a predetermined amount in response to the detected occlusion and actuates the plunger of the syringe into the barrel until a measured fluid pressure within the barrel of the syringe exceeds another predetermined threshold.