Two-Stage Peristaltic Pump for Flow Cytometry
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Solution Overview
Problem
Conventional peristaltic pumps used in flow cytometry experience pulsations in fluid pressure, leading to non-uniform flow rates and reduced accuracy, while alternatives like air compression or syringe pumps have drawbacks such as complexity with small volume containers and difficulty in handling varying media and volumes.
Innovation Solution
A two-stage peristaltic pump design where the first stage intermittently pressurizes fluid to the desired output pressure, and the second stage maintains a constant flow rate, using rollers orbiting at varying and constant angular speeds around circular disks to minimize pulsations and ensure consistent pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional peristaltic pump is used, then the fluid can be pumped through flexible tubing with minimal contamination, but the pump produces pulsations in fluid pressure leading to non-uniform flow rates
Solution Approach 1:
The pump is divided into two independent stages: a first stage with first rollers and a first disk for pressurization, and a second stage with second rollers and a second disk for flow maintenance. This segmentation allows each stage to perform its specific function optimally without interfering with the other, resolving the contradiction between contamination prevention and pressure uniformity.
Solution Approach 2:
The patent introduces an intermediary component - the first stage pressurization mechanism - that acts as a mediator between the fluid source and the second stage constant flow delivery. This intermediary stage eliminates pressure pulsations before the fluid enters the second stage, ensuring uniform flow while maintaining the peristaltic pumping advantage of fluid-contact-only-with-tubing.
2Stability of the object's composition
If air compression pumps or syringe pumps are used as alternatives, then pulsations can be reduced, but the device complexity increases or handling of varying media and volumes becomes difficult
Solution Approach 1:
The two-stage peristaltic pump design is universal and can handle varying media and volumes effectively. Both stages use the same peristaltic mechanism with flexible tubing, allowing the system to adapt to different fluid types and volumes without requiring complex mechanical changes, unlike air compression or syringe pumps.
Solution Approach 2:
The patent replaces complex mechanical systems (air compression mechanisms or syringe mechanisms) with a simpler peristaltic pumping mechanism in both stages. The fluid is moved entirely by the compression and relaxation of flexible tubing, eliminating the need for complex seals, pistons, or compression chambers while maintaining pressure uniformity.
3Stress or pressure
If the first rollers orbit at a first angular speed to increase fluid pressure, then the desired output pressure is achieved, but the flow rate becomes non-uniform due to pulsations
Solution Approach 1:
The pumping function is segmented into two distinct stages: the first stage focuses on pressure generation by orbiting first rollers at a first angular speed, while the second stage focuses on uniform flow delivery by orbiting second rollers at a second angular speed. This segmentation allows pressure and flow uniformity to be optimized independently in each stage.
Solution Approach 2:
The first stage acts as an intermediary that generates the required output pressure and delivers it to the second stage. The second stage then takes this pressurized fluid and maintains constant flow rate, effectively mediating between the pressure-generating mechanism and the uniform flow requirement, thus resolving the contradiction between pressure achievement and flow uniformity.
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 two-stage peristaltic pump achieves a substantially constant pressure output, reducing pulsations and enhancing the accuracy and reliability of fluid flow in flow cytometry applications by maintaining consistent pressure throughout the pumping process.
Implementation Method 1
The fluid being pumped only contacts the flexible tubing and is not exposed to other pump components which could possibly cause contamination of the fluid being pumped
Data Source
AI summary
Methods and systems for pumping fluid through tubing are provided. Methods include orbiting one or more first rollers at multiple angular speeds around the periphery of a substantially circular first disk having a first radius with each first roller travelling at the same angular speed as the other first rollers, orbiting second rollers at a second angular speed around a substantially circular second disk having substantially the first radius, and increasing the pressure of fluid in tubing between one first roller and one second roller by causing the one or more first rollers to orbit at a first angular speed greater than the second angular speed so the one first roller moves along and fully compresses the tubing in a first section of the first disk, and simultaneously causing the one second roller to move along and fully compress the tubing in a first section of the second disk.