Patent ID: 7875109

Claim:
A method of spot sampling of a gas, comprising the steps of: a) providing a sample cylinder having first and second ends, said first end engaged to pressurized container having gas therein; b) providing a valve formed of a body having a conduit formed therethrough, said conduit containing a restrictor element having an orifice; c) affixing said valve to said second end of said sample cylinder d) allowing the passage of gas from said pressurized container into said sample cylinder; e) opening said valve to allow the passage of gas from said sample cylinder through said valve conduit; f) utilizing said restrictor element to block passage of said gas through said valve except by way of said orifice formed therethrough; g) allowing said gas to pass through said orifice, in such a manner as to decrease the flow rate of fluid therethrough, resulting in Joules-Thomson effect cooling; while h) utilizing material having low thermal conductivity associated with said restrictor to isolate said Joules-Thomson effect so as to prevent condensation in said valve body conduit and said sample cylinder.