Chromatographic apparatus

A chromatographic analyzer comprising:

• a chromatographic column to separate the components of a fluid sample introduced to same;
• detecting means in operable communication with said chromatographic column for detecting a property of a fluid representative of the composition thereof;
• sample valve means in operable communication with said chromatographic column, said sample valve means having a sample chamber calibrated to contain a predetermined volume of sample;
• means for maintaining said chromatographic column, said detecting means and said sample valve means at a temperature T;
• conduit means in operable communication with said sample valve means for passing a fluid sample stream at a first pressure P.sub.1 to said sample valve means and through said sample chamber;
• valve means downstream of said sample chamber for terminating the flow of sample stream therethrough;
• means in operable communication with said conduit means for increasing the pressure on the portion of said sample stream in said conduit means and in said sample chamber from said pressure P.sub.1 to a higher pressure P.sub.2, said pressure P.sub.2 being sufficient to maintain said sample in the liquid state at said temperature T;
• relief valve means downstream of said sample chamber for allowing said sample stream to flow through said sample chamber at said pressure P.sub.2, said relief valve means being normally closed and preset to open at said pressure P.sub.2 ;
• and
• means for introducing a portion of said sample stream at said pressure P.sub.2 into said chromatographic column.