Flow Control Circuit Reduces Fluid Carryover in Flow Cytometers
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Solution Overview
Problem
Conventional fluid supply mechanisms in flow cytometers suffer from significant carryover between fluids, leading to potential instrument contamination and the need for manual cleaning, which is inefficient and does not ensure low fluid carryover without user intervention.
Innovation Solution
The development of a fluid supply system that includes an operating fluid line, a primary flushing fluid line, a secondary fluid line, and a flow control circuit configured to selectively permit the passage of flushing and secondary fluids, ensuring minimal carryover and automated fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional fluid supply mechanisms are used, then the system structure is simple, but fluid carryover between different fluids is significant leading to instrument contamination
Solution Approach 1:
The fluid supply system is divided into multiple independent fluid lines (first fluid line, second fluid line, third fluid line) that are spatially segmented and selectively connected to the flow cell. This segmentation prevents mixing and carryover between different fluids while maintaining a relatively simple overall structure through automated valve control.
Solution Approach 2:
Automated switching valves are introduced as intermediary components between the multiple fluid lines and the flow cell. These valves act as mediators that selectively connect only the required fluid line to the flow cell, preventing direct contamination between fluid lines while managing complexity through intelligent control rather than physical isolation of all lines.
2Ease of operation
If manual cleaning processes are implemented, then instrument contamination can be addressed, but user intervention is required and cleaning efficiency is low
Solution Approach 1:
The system implements self-service cleaning through automated flushing mechanisms where inert gas or cleaning fluids are automatically pumped through the fluid lines and flow cell after use. The system performs its own cleaning without requiring manual disassembly or user intervention, thereby improving both ease of operation and cleaning efficiency simultaneously.
Solution Approach 2:
The system performs preliminary flushing actions by automatically circulating cleaning fluids through the fluid pathways immediately after sample analysis is complete. This preliminary cleaning action prevents contamination buildup and prepares the system for the next sample, eliminating the need for subsequent manual cleaning while maximizing productivity.
3Reliability
If multiple fluid lines are used to reduce carryover, then fluid purity is improved, but the number of components and system complexity increases
Solution Approach 1:
The automated switching valves serve multiple functions: they selectively connect different fluid lines to the flow cell, control fluid flow direction, prevent carryover between fluids, and enable automated cleaning sequences. This multi-functionality allows the system to achieve high fluid purity through multiple dedicated lines without proportionally increasing overall system complexity, as a single valve component performs several critical roles.
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 effectively reduces fluid carryover by 80% or more, ensuring 100% swept cleaning and minimizing the risk of instrument contamination, while also eliminating the need for manual cleaning processes.
Implementation Method 1
a flow control circuit fluidically connected to the distal end of the primary flushing fluid line and the distal end of the secondary fluid line, and configured to selectively permit passage of the primary flushing fluid and the secondary fluid through an outlet
Implementation Method 2
a sheath fluid is provided to the flow cell by a pressure driven fluidics system where the sample fluid and sheath fluid are passed through the flow cell under pressure greater than ambient pressure
Implementation Method 3
the ratio of sample fluid to sheath fluid in hydrodynamic flow is determined by the exerted pressure in the sample source and sheath fluid reservoir
Implementation Method 4
Flow cytometers can also use a vacuum-driven fluidics system where a vacuum pump draws vacuum downstream from the flow cell and the sample and sheath fluids remain at ambient pressure
Data Source
AI summary
Fluid supply systems are provided. Fluid supply systems of interest include an operating fluid line, a primary flushing fluid line, a secondary fluid line, a flow control circuit fluidically connected to the distal end of the primary flushing fluid line and the distal end of the secondary fluid line, and configured to selectively permit passage of a primary flushing fluid and a secondary fluid through an outlet, and a single fluidic connection configured to fluidically couple to the flow control circuit, the operating fluid line, and a fluidic component of an instrument. Methods of analyzing a sample and assembling an instrument are also provided.