Floating-Disk Microfluidic Check Valve for LC Pressure Pulses
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Solution Overview
Problem
In liquid chromatography systems, back flow and pressure pulses occur when switching from bypass to main-pass mode, causing disturbances in the stationary phase, sample dispersion, and reducing data quality, and existing solutions require pre-pressurization or modification of injection valves.
Innovation Solution
A microfluidic check valve with a body, inlet bore, outlet bore, and floating disk that moves between open and closed positions in response to pressure differentials, preventing back flow and pressure pulses by allowing fluid flow from the inlet to the outlet while blocking reverse flow, and is designed to withstand high pressures and have a nanoliter-scale volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a multi-port injection valve is switched from bypass mode to main-pass mode, then sample injection into the mobile phase flow is achieved, but back flow and pressure pulses occur causing column instability and data quality reduction
Solution Approach 1:
A check valve is introduced as an intermediary component between the injection valve and the column. This check valve allows forward flow from the pump to the column while blocking reverse flow from the column back to the injection valve, thereby eliminating back flow and pressure pulses that cause column instability during mode switching
2Reliability
If the injection valve is modified to pre-pressurize the sample loop, then back flow is prevented, but device complexity increases
Solution Approach 1:
The back flow prevention function is extracted from the injection valve and implemented as a separate, standalone check valve component. This simplifies the injection valve design while maintaining reliable back flow prevention, as the check valve automatically responds to pressure differentials without requiring complex modifications to the injection valve mechanism
3Reliability
If a traditional check valve is used, then back flow is blocked, but the valve volume causes sample dispersion
Solution Approach 1:
The check valve employs a thin, flexible disk that can deflect rapidly in response to pressure differentials. This thin-film design minimizes the internal volume of the check valve, thereby reducing sample dispersion while maintaining effective back flow blocking capability through the rapid response of the flexible disk
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 microfluidic check valve effectively prevents back flow and pressure pulses, maintaining column stability and data quality without requiring pre-pressurization or injection valve modification, and can operate reliably in high-pressure LC systems with minimal sample dispersion.
Implementation Method 1
the disk is freely movable between an open position and a closed position in response to a pressure differential between the inlet bore and the outlet bore
Data Source
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AI summary
A microfluidic check valve (164, 264, 400) includes an inlet bore (442), an internal chamber (438), an outlet bore (446), and a disk (454) freely movable in the chamber (438) between an open position and a closed position. At the open position, the disk (454) permits fluid to flow from the inlet bore (442), through the chamber (438), and to the outlet bore (446). At the closed position, the disk (454) prevents fluid from flowing in the reverse direction from the chamber (438) into the inlet bore (442). The check valve (164, 264, 400) may be positioned in-line with a fluid conduit or capillary tube, and/or incorporated with various fluidic devices such as, for example, capillary tubes, fittings, and chromatography columns. The check valve (164, 264, 400) is capable of withstanding high fluid pressures, while featuring a small swept volume, such as a nano-scale volume. The check valve (164, 264, 400) may be utilized, for example, to prevent fluid back flow and isolate pressure pulses in fluid flow systems.