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Liquid nitrogen as cryogenic

Question asked by alhartmm on Feb 14, 2020
Latest reply on Feb 14, 2020 by james_jenkins



I have an issue with my GC’s . I use a liquid nitrogen from 140 L dewar to cool down the GC oven to -5 Cْ for DHA test . The pressure coming from the dewar is about 400 psi when I run the test it takes time to cool to make the GC ready then it shutdown before starting the run . I have to release   the dewar pressure using the vent valve to 100 psi to make the GC work. I tried to find a liquid regulator to decrease the pressure going to the GC because I want to decrease the liquid nitrogen consumption and make the GC work without venting the pressure but I couldn’t find one. The GC LN2 cryogenic valve  maximum operating pressure differential is 50 psi is it okay to replace valve with a high pressure cryogenic valve to solve this issue ? Or is there any idea about solving this issue ?  



Thank you