Two-Stage Peristaltic Pump for Stable Fluid Delivery

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Solution Overview

Problem

Conventional peristaltic pumps produce pulsating output with varying pressure, which is undesirable in applications like flow cytometry, leading to fluctuations in sample volume and affecting data accuracy, and additional rollers to smooth pulsations reduce tubing lifespan and increase maintenance costs.

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

VSEngineering Contradiction Analysis

1Stress or pressure

If conventional peristaltic pumps are used, then fluid pumping is achieved, but pulsating output with varying pressure is produced

Engineering Contradiction:
Improveoutput pressure stabilityVSAvoidflow consistency
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The pump system is divided into multiple pumping units, each with its own roller and tubing section. By segmenting the pumping action into discrete units that operate in sequence, the pulsating output from individual units is averaged out, producing a more stable overall flow and pressure output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the tubing are subjected to different compression timing and duration. The roller compresses different portions of the tubing at different phases of the rotation cycle, creating localized variations in flow resistance that collectively smooth out pressure fluctuations across the entire system.

Inventive Principle:
Principle #3Local quality

2Stress or pressure

If additional rollers are added to smooth pulsations, then pressure stability is improved, but tubing lifespan is reduced

Engineering Contradiction:
Improvepressure stabilityVSAvoidtubing lifespan
Core Design Contradiction:
Stress or pressureVSDuration of action of stationary object

Solution Approach 1:

Instead of using fewer large rollers, the system uses multiple smaller rollers that segment the compression points along the tubing. This distributes the mechanical stress across more contact points, reducing the cumulative wear at any single location and extending tubing life while maintaining pressure stability.

Inventive Principle:
Principle #1Segmentation

3Stress or pressure

If multiple rollers are used to reduce pulsation, then pressure stability is improved, but maintenance costs increase

Engineering Contradiction:
Improveoutput pressure stabilityVSAvoidmaintenance cost
Core Design Contradiction:
Stress or pressureVSEase of repair

Solution Approach 1:

The pump design allows for easy roller replacement and tubing adjustment without requiring complex disassembly or specialized tools. The modular structure enables users to perform basic maintenance themselves, reducing the need for professional service interventions and lowering overall maintenance costs.

Inventive Principle:
Principle #25Self-service

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 pump achieves a substantially constant output pressure, reducing pulsation and wear on tubing, thereby improving data accuracy and extending tubing lifespan while minimizing maintenance costs.

Implementation Method 1

Peristaltic pumps are positive displacement pumps. The fluid being pumped only contacts the flexible tubing and is not exposed to other pump components which could possibly cause cross-contamination.

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Implementation Method 2

the tube is deformed into a flat shape with two bent portions to transfer a slurry within the tube

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

squeeze pump having an elastic tube disposed between an inlet and an outlet

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3337977B1Continuous sample delivery peristaltic pump
Publication Date: 2020.01.29 BIO RAD LABORATORIES INC
  • EP3337977B1 patent drawingFigure 1
  • EP3337977B1 patent drawingFigure 2
  • EP3337977B1 patent drawingFigure 3A~3B

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.