Sample injection on gas chromatographs - using pressure regulated purge on injection chamber

摘要

Gas chromatograph has an input seal for injecting samples. This consists of an inner chamber into which carrier gas is continuously admitted and an outer chamber which is flushed with purge gas and into which the sample is introduced. The pressure of the purge gas in the outer chamber is controlled either by a relief valve and/or an adjustable pressure reducing valve on the purge gas inlet. The pressure reducing valve can be by passed by an on/off valve. For use with gas phase chromatographic analysis of liquid samples. Generally the purge gas chamber is at a higher pressure than the inner chamber and when the sample is injected, a pressure surge enters the column and can upset it. This method avoids such a surge.