Two-Stage Peristaltic Pump for Constant Fluid Pressure
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Solution Overview
Problem
Conventional peristaltic pumps produce pulsed output with varying pressure, which is undesirable in applications like flow cytometry, leading to fluctuations in sample volume and affecting data accuracy, and existing solutions like using three rollers to smooth out pulsations increase maintenance costs and reduce tubing lifespan.
Innovation Solution
A two-stage peristaltic pump design with first and second disks of varying radii, where first rollers move at different tangential speeds to increase pressure and second rollers maintain constant pressure, ensuring a substantially constant output pressure by synchronizing the rotation of rollers around the disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional peristaltic pumps use single-stage design with uniform roller speed, then the device complexity is low, but the output pressure varies pulsatingly which affects measurement precision
Solution Approach 1:
The pump is divided into two distinct stages: a first stage with a first disk having varying radius to generate pressure, and a second stage with a second disk having constant radius to maintain constant output pressure. This segmentation allows each stage to perform its specific function optimally, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The first disk is designed with dynamically varying radius (different in first and second angular sectors) to create pressure variations during rotation, while the second disk maintains constant radius for stable output. This dynamic design enables pressure generation followed by pressure stabilization, improving measurement precision without excessive complexity.
2Stability of the object's composition
If three rollers are used to smooth out pulsations, then the output pressure stability improves, but the tubing lifespan decreases and maintenance costs increase
Solution Approach 1:
Instead of adding more rollers to the same stage, the invention segments the pumping action into two stages with different disk configurations. The first stage generates pressure with varying roller speed, and the second stage stabilizes pressure with constant roller speed, achieving pressure stability without increasing roller count or tubing wear.
Solution Approach 2:
The invention changes the operational parameters by using two different disk radius configurations (varying vs. constant) rather than changing the number of rollers. This parameter change achieves pressure stability while maintaining the original single-roller-per-disk configuration, thus preserving tubing lifespan.
3Stress or pressure
If the first disk has varying radius to create pressure, then the pressure generation capability improves, but the manufacturing precision requirements increase
Solution Approach 1:
The varying radius requirement is segmented into only two distinct angular sectors (first and second sectors) rather than continuous variation. This simplifies manufacturing compared to complex curved profiles, as each sector can be manufactured with standard tolerances and then joined, reducing overall manufacturing precision requirements while still achieving pressure generation.
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 design achieves a substantially constant output pressure, reducing pulsation and maintaining fluid pressure consistency, thus improving data accuracy in flow cytometry and other applications while minimizing maintenance and wear on tubing.
Implementation Method 1
The fluid being pumped only contacts the flexible tubing and is not exposed to other pump components which could possibly cause cross-contamination. Peristaltic pumps are especially suited for pumping abrasives, viscous fluids and biological fluids.
Implementation Method 2
The first disk may include a first angular sector that is configured to cause the first rollers to move along a first section of the periphery of the first disk at a first tangential speed and a second angular sector that is configured to cause the first rollers to move along a second section of the periphery of the first disk at a second tangential speed less than the first tangential speed.
Data Source
AI summary
A method and apparatus for pumping fluid through tubing are provided. The method includes orbiting first rollers around the periphery of a first disk at a first tangential speed in a first angular sector and a slower, second tangential speed in a second angular sector, orbiting second rollers around the periphery of a second disk at the second tangential speed, and increasing the pressure of fluid in tubing between one first roller and one second roller by causing the one first roller to fully compress the tubing at the first tangential speed and simultaneously causing the one second roller to fully compress the tubing at the second tangential speed. The apparatus includes a first disk with a recess in its periphery, the first angular sector with a nominal first radius, and a second angular sector with a nominal second radius; and a second disk with the nominal first radius and a recess in its periphery.