Gas Chromatograph Bypass Loop for Sample Gas Concentration Control
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Solution Overview
Problem
Gas chromatography requires precise control of sample gas concentration to avoid overloading the stationary phase, which can lead to distorted measurement signals and misinterpretation of gas components, especially in simple columns without temperature control.
Innovation Solution
A gas chromatograph assembly with a sample gas inlet, secondary gas inlet, infrared sensor, and bypass loop allows for the gradual reduction of sample gas concentration through continuous mixing with a secondary gas, using flow regulators and a gas modulation valve to achieve a suitable ratio, enabling controlled dilution and precise concentration adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sample gas concentration is increased to achieve a sufficient measurement signal, then the measurement signal strength is improved, but the stationary phase becomes overloaded causing distorted peaks and misinterpretation of gas components
Solution Approach 1:
The system dynamically adjusts the sample gas concentration by controlling the number of circulation cycles through the mixing loop. The concentration is not fixed but varies adaptively based on the required measurement signal level, allowing optimization between signal strength and peak shape preservation
Solution Approach 2:
The invention changes the concentration parameter of the sample gas by circulating it through the mixing loop multiple times with secondary gas. This parameter adjustment allows the system to find the optimal concentration level that provides sufficient signal without overloading the stationary phase
2Manufacturing precision
If the sample gas concentration is decreased to avoid overloading the stationary phase, then the peak distortion is reduced, but the measurement signal becomes insufficient
Solution Approach 1:
The system maintains continuous circulation of the gas mixture through the mixing loop, allowing multiple passes of dilution and mixing. This continuous process enables gradual concentration adjustment while maintaining measurement capability through accumulated signal from multiple analysis cycles
Solution Approach 2:
The sample gas is preliminarily diluted and mixed in the circulation loop before being introduced to the column. This preliminary concentration adjustment ensures that the gas enters the column at an optimal concentration, preventing overload while maintaining sufficient signal for detection
3Device complexity
If a simple column without temperature control is used to reduce device complexity, then the device complexity is reduced, but the concentration control becomes more critical and difficult
Solution Approach 1:
The mixing loop with secondary gas acts as an intermediary system between the sample gas source and the column. This intermediary mechanism provides precise concentration control without requiring complex temperature control, transferring the control function to a simpler mixing process
Solution Approach 2:
The invention replaces the mechanical/thermal control system (temperature control) with a gas phase mixing system. Instead of controlling concentration through temperature variations, the system uses gas flow mixing and circulation, simplifying the overall device while maintaining control capability
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 method ensures a sufficient measurement signal without overloading the stationary phase, allowing for accurate identification of gas components by maintaining optimal sample gas concentration, thereby preventing peak distortion and misinterpretation.
Implementation Method 1
Gas chromatography is also used in the field of gas leak detection... a gas chromatograph infrared sensor, a gas chromatograph column, and a gas chromatograph bypass parallel to the column
Data Source
AI summary
Method for adapting the concentration of a sample gas in a gas mixture to be analysed by a gas chromatograph assembly (10), the gas chromatograph assembly (10) comprising a sample gas inlet (20) for introducing a sample gas to be analysed, a secondary gas inlet (40), a gas chromatograph infrared sensor (12), a gas chromatograph column (26), and a gas chromatograph bypass (28) parallel to the column (26), characterized bya) introducing an amount of sample gas through the sample gas inlet (20),b) introducing an amount of secondary gas through the secondary gas inlet (40),c) mixing the sample gas and the secondary gas to a gas mixture and conducting the gas mixture via the gas chromatograph bypass (28),d) circulating the gas mixture in a gas conducting loop (52) comprising the gas chromatograph bypass (28), the gas chromatograph infrared sensor (12) and not comprising the gas chromatograph column (26),e) analysing the gas mixture thus obtained by means of gas chromatography employing the gas chromatograph column (26) and the gas chromatograph infrared sensor (12).