Purge Method for Low Pressure Gradient Liquid Chromatography
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Solution Overview
Problem
In low pressure gradient liquid chromatography systems, static fluid volumes in unused fluid channels can lead to contamination when not intended for use, causing noise and drift in isocratic chromatographs and reducing measurement accuracy over time.
Innovation Solution
A method for purging fluid channels involves controlling valves and a pump system to draw and replace static volumes of liquids in fluid channels with a primary liquid, ensuring only the intended solvent is present, thereby preventing contamination and maintaining system accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system operates in isocratic mode with one valve open and others closed for extended idle periods, then the system maintains operational readiness, but static fluid volumes in unused fluid channels migrate and contaminate downstream channels
Solution Approach 1:
The system performs preliminary purging action before isocratic operation to prevent contamination. The processor executes a purge sequence that draws fluid through unused channels and replaces it with fresh solvent from the pump system, eliminating static fluid volumes before they can migrate and contaminate downstream channels during extended idle periods.
Solution Approach 2:
The harmful static fluid volumes are extracted from the unused fluid channels through the purging process. The pump system draws the contaminated static fluid out of the channels and replaces it with clean solvent, removing the source of contamination before isocratic operation begins.
2Ease of operation
If static fluid volumes are allowed to remain in unused fluid channels, then the system maintains simple operation without additional purging steps, but measurement accuracy deteriorates due to noise and drift
Solution Approach 1:
The purging operation is performed as a preliminary step before isocratic chromatography to eliminate static fluid volumes that would otherwise cause measurement errors. This automated preliminary action maintains measurement precision without significantly complicating the overall operation, as the purging sequence is automatically controlled by the processor.
3Object-affected harmful factors
If the pump system continuously circulates fluid through all channels, then contamination is prevented, but energy consumption and system complexity increase
Solution Approach 1:
Instead of continuous circulation, the system employs periodic purging action. The processor monitors system state and activates the pump system to purge unused channels only when needed (e.g., before isocratic operation or after gradient sequences), rather than maintaining continuous flow. This periodic approach prevents contamination while minimizing energy consumption compared to continuous circulation.
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 method effectively prevents contamination and maintains the accuracy of isocratic separations by ensuring only the intended solvent is present in fluid channels, reducing noise and drift in chromatographic measurements.
Implementation Method 1
drawing the first liquid from the first valve through the first fluid channel, the cross connection, the third fluid channel and the pump system
Implementation Method 2
The first liquid is supplied from the pump system through the third fluid channel, the cross connection, and the second fluid channel to at least the second valve to thereby replace the volume of the second liquid in the second fluid channel with the first liquid
Data Source
AI summary
Described is a method for purging a fluid channel is a low pressure gradient formation liquid flow system. Control of the fluid channels for multiple solvents allows for one or more static volumes of solvents not intended for use in an isocratic flow to be purged from their fluid channels to avoid contamination of the isocratic solvent. Advantageously, the method avoids the need to modify equipment or to reconfigure a pumping system so that the inlet is directly coupled to a single solvent source. Thus there is no need to bypass existing valves and liquid coupling components where solvents are combined during conventional gradient operation.