Peristaltic Pump Split Plunger Spring Force Reduction
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Solution Overview
Problem
Existing peristaltic pumps face challenges in accurately measuring fluid volume without damaging tubing or causing out-gassing during measurement phases, which can lead to potential harm to patients due to tubing wear and gas embolisms.
Innovation Solution
The peristaltic pump design incorporates a split plunger mechanism with independent biasing members and camshaft configurations that allow for volume measurement without a dedicated measurement phase, using coordinated actuators and cam lobes to maintain contact with the tubing while minimizing pressure and preventing flow disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated measurement phase is used to measure fluid volume, then measurement precision is improved, but tubing damage and out-gassing occur
Solution Approach 1:
The patent removes the dedicated measurement phase from the pumping cycle, extracting the harmful measurement action that causes tubing damage and out-gassing. Instead, volume measurement is performed continuously during normal pumping operations, eliminating the need for separate measurement cycles that apply excessive force to the tubing.
Solution Approach 2:
The patent combines the volume measurement function with the normal pumping operation. The same plunger that performs pumping also performs measurement continuously during the pumping cycle, merging two functions into one seamless operation to avoid the harmful effects of separate measurement phases.
2Reliability
If plunger force is increased to ensure contact with tubing during pumping, then pumping reliability is improved, but tubing damage occurs
Solution Approach 1:
The patent employs dynamic force adjustment where the biasing member provides variable force rather than constant high force. The spring force automatically adjusts to maintain plunger contact with the tubing during normal pumping while reducing force during expansion phases, preventing tubing damage while ensuring reliable operation.
Solution Approach 2:
The patent changes the force parameter dynamically through the spring biasing member, allowing the plunger force to vary during different phases of the pumping cycle. This parameter change ensures sufficient contact force for reliable pumping while limiting maximum force to prevent tubing damage.
3Measurement precision
If plunger is lifted off cam shaft during measurement, then measurement precision is improved, but flow disruption occurs
Solution Approach 1:
The patent maintains continuous plunger contact with the tubing throughout the entire pumping cycle, eliminating interruptions in the useful pumping action. The biased plunger remains engaged with the tubing during both compression and expansion phases, ensuring continuous flow without disruption or out-gassing while still enabling accurate volume measurement.
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 accurate fluid volume measurement without damaging tubing or causing out-gassing, ensuring safe and reliable fluid administration by maintaining contact with the tubing throughout the pumping cycle.
Implementation Method 1
a first biasing member configured to urge the plunger toward the tubing segment to maintain contact with the tubing segment in the engaged position
Implementation Method 2
a camshaft comprising a first plunger cam lobe, wherein the first plunger cam lobe is configured to move the plunger between an engaged position in contact with the pumping volume and a disengaged position spaced apart from the pumping volume
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Peristaltic pumps are described herein. In certain embodiments, a peristaltic pump includes a plunger, a camshaft, and a first biasing member. The plunger is movable to selectively engage a pumping volume of a tubing segment. The camshaft includes a first plunger cam lobe. The first plunger cam lobe is configured to move the plunger between an engaged position in contact with the pumping volume and a disengaged position spaced apart from the pumping volume. The first biasing member is configured to urge the plunger toward the tubing segment to maintain contact with the tubing segment in the engaged position.