Split-Plunger Peristaltic Pump for Low-Pressure Volume Measurement
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Solution Overview
Problem
Existing peristaltic pumps face challenges in accurately measuring fluid volume without causing damage to tubing or inducing high internal pressures, which can lead to tubing wear and gas out-gassing, potentially harming patients.
Innovation Solution
The peristaltic pump design incorporates a split plunger mechanism with independent biasing members and camshaft actuation to maintain contact with the tubing during expansion and contraction phases, allowing for volume measurement without a dedicated measurement phase and minimizing internal pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a peristaltic pump uses traditional plunger engagement with tubing, then fluid pumping function is achieved, but tubing damage and high internal pressure occur
Solution Approach 1:
The plunger is designed to dynamically adjust its engagement with the tubing through biased contact during expansion and controlled disengagement during contraction. The plunger maintains contact during the expansion phase to measure volume accurately, then allows separation during contraction to reduce internal pressure and prevent tubing damage.
Solution Approach 2:
The pump operates through periodic cycles of expansion and contraction. During expansion, the plunger engages the tubing for volume measurement; during contraction, the plunger disengages to minimize harmful pressure. This periodic engagement-disengagement pattern eliminates continuous harmful pressure while maintaining pumping function.
2Measurement precision
If a peristaltic pump uses traditional measurement methods, then fluid volume can be measured, but a dedicated measurement phase is required which reduces productivity
Solution Approach 1:
The measurement function is merged with the pumping function. The plunger serves dual purposes: it contracts the tubing to pump fluid during the contraction phase, and simultaneously measures the volume of the pumping segment during the expansion phase. This eliminates the need for a separate dedicated measurement phase, maintaining continuous productivity while achieving accurate volume measurement.
Solution Approach 2:
The plunger is designed as a multi-functional component that performs both pumping and measurement tasks. During expansion, it measures the volume of the pumping segment; during contraction, it pumps fluid by compressing the tubing. This universal design allows the single component to execute multiple functions without requiring additional dedicated measurement mechanisms or phases.
3Measurement precision
If a peristaltic pump maintains continuous contact with tubing, then volume measurement is possible, but tubing wear increases
Solution Approach 1:
The plunger-tubing contact is made dynamic rather than continuous. The plunger maintains contact during the expansion phase for volume measurement, then disengages during the contraction phase. This dynamic contact pattern enables measurement while significantly reducing cumulative wear on the tubing compared to continuous contact, thereby extending tubing service life.
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 enables accurate fluid volume measurement without damaging tubing or causing gas out-gassing, reducing the risk of tubing wear and patient harm by maintaining consistent contact and controlled force application.
Implementation Method 1
a first biasing member configured to urge the plunger toward the tubing segment to maintain contact with the tubing segment during the expansion of the pumping volume
Implementation Method 2
a second biasing member configured to urge the plunger toward the tubing segment to contract the pumping volume
Implementation Method 3
an IV pump uses peristaltic manipulation of a segment of tubing of an IV set to create the flow of medical fluid to the patient
Data Source
AI summary
Peristaltic pumps are described herein. In certain embodiments, a peristaltic pump includes a plunger, a first biasing member, and a second biasing member. The plunger is movable to selectively engage a pumping volume of a tubing segment to expand the pumping volume to draw fluid flow into the pumping volume and to contract the pumping volume to conduct fluid flow 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 during the expansion of the pumping volume. The second biasing member is configured to urge the plunger toward the tubing segment to contract the pumping volume.