Peristaltic Pump Occlusion Timing for Backflow Control
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Solution Overview
Problem
Peristaltic pumps experience inconsistent liquid flow due to backflow, where suction exceeds pumping action at the end of each cycle, leading to undesirable fluid dynamics in therapeutic applications.
Innovation Solution
The occlusion means in the downstream part of the pump remain in the occlusive position for a greater portion of the cycle than those upstream, ensuring no backflow by maintaining pressure equality before releasing the occlusion, achieved by adjusting the counter surface proximity to the rotation shaft and using longer or inclined fingers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump operates with standard occlusion timing, then the pump structure is simple, but backflow occurs causing inconsistent flow rate
Solution Approach 1:
The patent applies dynamic timing control where the occlusion duration of each finger is varied based on its position in the pumping cycle. Downstream fingers maintain occlusion longer than upstream fingers, creating an overlapping occlusion pattern that prevents backflow. This dynamic adjustment of occlusion timing resolves the contradiction by achieving consistent flow rate without requiring complex acceleration mechanisms.
2Reliability
If downstream occlusion is extended to prevent backflow, then flow rate consistency improves, but the pump cycle duration increases
Solution Approach 1:
The patent implements preliminary action by having downstream fingers begin occlusion before upstream fingers complete their pumping action. This overlapping timing ensures that the downstream occlusion is already in place to prevent backflow when the upstream finger releases, thereby maintaining consistent flow rate without significantly extending the overall pump cycle duration.
3Reliability
If motor speed is increased to counter backflow, then flow rate consistency improves, but energy consumption increases
Solution Approach 1:
The patent changes the timing parameter of occlusion duration for each finger rather than increasing motor speed. By extending the occlusion duration of downstream fingers relative to upstream fingers, the system prevents backflow through parameter optimization rather than brute-force speed increase, thereby maintaining flow rate consistency while minimizing energy consumption.
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 design eliminates backflow, enhances flow rate consistency, increases pumped volume, reduces energy consumption, and minimizes motor size and noise, resulting in improved pump efficiency.
Implementation Method 1
peristaltic pump comprising occlusion means for compressing a flexible tube, creating at least one zone of occlusion moving cyclically from an upstream part to a downstream part of the pump
Implementation Method 2
the rollers flatten the tube in the raceway, generating a suction zone behind them and a compression zone in front of them
Data Source
AI summary
A method for controlling the flow rate of a peristaltic pump includes compressing a flexible tube, forming at least one occlusion region that moves cyclically downstream from the upstream end of the pump, and compressing the tube in the direction of a counter surface to form an occlusion. A peristaltic pump can be used to carry out the method so as to suppress reverse flow without altering the speed of the motor. The occlusion in the most downstream part of the pump remain in the occluding position for a longer portion of the cycle than the occlusion in a more upstream part of the pump, preferably for longer than the compression in the most upstream part of the pump.