Gas and liquid inlet system for chromatography

Claim 1

A unitary valve mechanism for controlling the inlet of a gas or liquid sample into a gas chromatograph column comprising: a valve body adapted to be connected directly to said column, said valve body having a substantially cylindrical or conical shaped opening therein; a valve plug mounted in said opening in said valve body and being rotatable between first and second positions; a sample loop, the opposite ends of which extend into said valve body and communicate with said valve plug; a sample gas inlet passage and a sample gas outlet passage in said valve body each communicating with said valve plug; a carrier gas inlet passage having a portion thereof in communication with said valve plug; said valve body having elongated channel sections extending therethrough, said channel sections communicating with said valve plug; said valve plug having a first straight groove therein cooperating with said elongated channel sections in said valve body when said valve plug is in its first position to form an elongated channel extending entirely through said valve body and said plug, said channel being coaxial with said column whereby a syringe needle may be inserted to inject a liquid sample into said column, said valve plug also being operative when in its first position to connect said carrier gas inlet passage directly to said elongated channel, said valve plug being further operative, in said first position, to connect said sample gas inlet and outlet passages to said ends of said sample loop, respectively, whereby said sample gas circulates through said loop, said valve plug being operative, upon rotation to its second position, to connect said carrier gas inlet passage to said elongated channel via said sample loop whereby carrier gas from said carrier gas inlet passage flushes the sample gas trapped in said sample loop into said channel and thence into said column.