Dual-Pump Fluid Junction for Stable Low-Pulsatility Sheath Flow
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Solution Overview
Problem
Flow cytometers face challenges in delivering stable sheath flow rates at both high and low flow rates, particularly with viscous fluids, due to limitations in pump and fluidic channel systems, leading to pulsatility and reduced accuracy in particle analysis.
Innovation Solution
A system comprising multiple pumps configured to operate in different modes, providing a fluid flow with a minute measure of pulsatility, allowing for a wide dynamic range of flow rates, including the use of gear pumps that run at high RPM to reduce pulsatility and increase precision, and the incorporation of pressure sensors for differential pressure measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump is used to deliver sheath fluid, then the system is simple, but the flow rate stability deteriorates at both high and low flow rates
Solution Approach 1:
The pump system is segmented into multiple independent pumps (e.g., first pump and second pump) that can operate simultaneously or independently. Each pump handles a portion of the total flow requirement, allowing the system to maintain stable flow rates across a wide dynamic range while reducing the pulsatility that would occur with a single pump operating at extreme speeds.
2Productivity
If high flow rate is used for high speed analysis, then productivity increases, but flow rate stability deteriorates
Solution Approach 1:
The total high flow rate requirement is divided into multiple smaller flow streams from separate pumps. This segmentation allows each pump to operate within its optimal stability range while collectively delivering the high total flow rate needed for high-speed analysis, thereby maintaining both productivity and flow rate stability.
3Measurement precision
If low flow rate is used for slow speed analysis, then measurement precision improves, but flow rate stability deteriorates
Solution Approach 1:
Multiple pump outputs are merged at a common junction to deliver the combined stable flow to the analysis system. This merging of flows from multiple stable sources ensures that the combined output maintains stability even at low total flow rates, enabling precise slow-speed particle analysis without the pulsatility problems of single-pump systems.
4Stability of the object's composition
If viscous sheath fluid is used, then particle alignment improves, but flow rate stability deteriorates
Solution Approach 1:
The viscous sheath fluid flow is segmented into multiple parallel streams from different pumps. This segmentation reduces the pulsatility that would otherwise occur with viscous fluid delivery, as each pump handles a smaller portion of the total viscous flow, thereby maintaining both the particle alignment quality provided by the viscous fluid and the flow rate stability needed for accurate analysis.
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 system achieves stable flow rates with minimal pulsatility, enabling reliable operation across a wide range of applications, including high and low flow rates, and reduces errors in particle analysis by maintaining consistent velocity and position through detection regions.
Implementation Method 1
the use of gear pumps that run at high RPM to reduce pulsatility and increase precision
Implementation Method 2
the incorporation of pressure sensors for differential pressure measurements
Data Source
AI summary
An embodiment of a system with a minute measure of pulsatility in a flow of a fluid is described that comprises a first pump configured to flow the fluid to a junction at a first flow rate that comprises a measure of pulsatility; and a second pump configured to flow a portion of the fluid from the junction at a second flow rate that is less than the first flow rate to produce a flow of the fluid at a third flow rate from the junction with a minute measure of pulsatility.