Gas Chromatography Injector Vacuum Standby Control
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Solution Overview
Problem
Gas chromatography systems consume large volumes of carrier gases, such as helium, even during idle periods, leading to inefficiency and increased costs, as traditional methods to reduce consumption can result in elevated baselines due to contaminants and oxidation of the column stationary phase.
Innovation Solution
Discontinuing the flow of carrier gas and applying vacuum to the injector during standby times, while maintaining a small residual purge gas flow or helium flow to prevent column oxidation, allows for helium conservation without compromising system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large split flows are used to dilute contaminants, then baseline stability is improved, but carrier gas consumption increases
Solution Approach 1:
The system implements periodic action by alternating between high split flow during active analysis to maintain baseline stability and low split flow during idle periods to conserve carrier gas. The controller automatically adjusts the split flow rate based on whether the system is in analysis mode or idle mode, achieving both baseline stability during operation and gas conservation during non-operation.
2Loss of substance
If split flow is reduced to conserve gas, then carrier gas consumption decreases, but baseline elevation occurs due to contaminants
Solution Approach 1:
The system implements periodic action by alternating between high split flow during active analysis to maintain baseline stability and low split flow during idle periods to conserve carrier gas. The controller automatically adjusts the split flow rate based on whether the system is in analysis mode or idle mode, achieving both baseline stability during operation and gas conservation during non-operation.
3Loss of energy
If carrier gas flow is discontinued during standby, then gas consumption and power usage decrease, but column oxidation may occur
Solution Approach 1:
The system implements periodic action by alternating between high split flow during active analysis to maintain baseline stability and low split flow during idle periods to conserve carrier gas. The controller automatically adjusts the split flow rate based on whether the system is in analysis mode or idle mode, achieving both baseline stability during operation and gas conservation during non-operation.
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
This approach significantly reduces helium consumption during non-runtime periods, conserves power, and prevents column oxidation, while enabling efficient cleaning and bakeout of inlet components.
Implementation Method 1
applying vacuum to the injector during standby times
Data Source
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AI summary
A gas chromatography (GC) system comprises: a sample injector adapted to receive a liquid sample into an interior cavity thereof and to volatilize the liquid sample; a GC column configured to receive the volatilized sample from the sample injector; a carrier gas inlet line fluidically coupled to a gas inlet port of the sample injector; a septum purge vent line fluidically coupled to a first gas outlet port of the sample injector; a split-flow vent line fluidically coupled to a second gas outlet port of the sample injector; and a vacuum system configured to apply vacuum to the septum purge vent line, the split-flow vent line and the interior cavity of the sample injector. Alternatively, the vacuum system may be coupled to a vacuum port of the sample injector. A separate flow of helium gas may be supplied to an inlet of the GC column.