CI Gas Line Purging With Cycle Timer for Reagent Purity
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Solution Overview
Problem
Mass spectrometry systems employing chemical ionization face challenges in maintaining ultra-high purity of reagent gases due to water vapor adsorption on internal surfaces, which is difficult to purge, especially at low flow rates, leading to interference and the need for extended flushing periods, resulting in inefficiencies and contamination.
Innovation Solution
A system utilizing a cycle timer to periodically flush the CI gas supply line, minimizing water contamination while reducing reagent gas waste by controlling the solenoid valve to allow gas flow through a bypass line to a vacuum pump, optimizing the purge duration based on flow rates and system usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If continuous gas flow is used to purge water vapor from the gas supply line, then water vapor contamination is reduced, but reagent gas is wasted
Solution Approach 1:
The system implements periodic purging of the gas supply line using a cycle timer that activates a solenoid valve at predetermined intervals (e.g., every 4-12 hours) rather than continuous purging. This periodic action maintains gas purity by removing adsorbed water vapor while significantly reducing reagent gas consumption compared to continuous flow methods.
2Loss of substance
If gas flow is stopped for several hours after equilibrium is established, then reagent gas consumption is reduced, but water vapor contamination increases
Solution Approach 1:
The system performs preliminary purging action before the gas flow is stopped, establishing a clean state in the supply line. The cycle timer activates the solenoid valve to purge water vapor just before equilibrium would be disturbed, ensuring that when gas flow resumes after extended stops, the line is already purified and contamination is minimized.
3Object-affected harmful factors
If gas cylinders are frequently replaced to maintain purity, then reagent gas purity is maintained, but system operation time is reduced
Solution Approach 1:
The system implements self-service purification through an automated cycle timer and solenoid valve assembly that periodically cleans the gas supply line without user intervention. This self-purging mechanism maintains gas purity over extended periods (days or weeks) between gas cylinder replacements, significantly extending system operation time while maintaining purity standards.
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 enhances the purity of reagent gases, reduces waste, and maintains system integrity by periodically purging the supply line, thereby improving CI mass spectrometry data quality without continuous gas flow and frequent gas source replacements.
Implementation Method 1
A cycle timer 220 can cause the solenoid valve 218 to be open for a first set period of time
Implementation Method 2
A bypass line 216 can be in communication with a foreline 212 of the vacuum pump 210
Data Source
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AI summary
A system including a gas source coupled to a mass spectrometer with a supply line to provide reagent gas for chemical ionization; a bypass line connecting the supply line to a foreline of a vacuum pump, the bypass line including a valve and a bypass restrictor; and a cycle timer operable to open the valve for a first period of time and close the valve for a second period of time.