Method and devices for improving the dynamic flash combustion reaction connected with gas chromatography for the elemental analysis of C H N S O

An elemental analyzer system comprising:

• a combustion reactor;
• a gas chromatographic analyzer connected to said combustion reactor;
• a pneumatic circuit connected to said combustion reactor, said pneumatic circuit passing a carrier gas through said combustion reactor and to said gas chromatographic analyzer;
• an oxygen feed line connected to said pneumatic circuit at an injection point upstream of said combustion reactor;
• a restriction, in said oxygen feed line arranged upstream of said injection point;
• and
• a processor for adjusting one of an amount and a duration of the oxygen fed to said pneumatic circuit by adjusting pressure upstream and downstream of said restriction.

The method for improving dynamic flash combustion reaction that is connected with gas chromatography for elemental analysis of C H N S O in an automatic elemental analyzer, the method comprising the steps of

• providing at least one combustion reactor;
• providing a sampling device;
• introducing a sample of material into the combustion reactor with the sampling device;
• providing an oxygen feed line with a restriction;
• admitting controlled volumes of oxygen with the oxygen feed line into the combustion reactor depending on the sample for the complete combustion thereof;
• providing a pneumatic circuit, in which the oxygen feed line converges and creating a continuous flow of a carrier gas that is able to carry the oxygen to the reactor and the gases of the combustion through the reactor, then through a gas chromatographic analyzer, and after their separation, into a thermal conductivity detector;
• providing an electronic apparatus with a data processor for regulating the oxygen flow based on a measurement of the differences in pressure upstream and downstream of said restriction;
• and
• injecting an identical volume of oxygen for a different duration of time by varying said pressure upstream and downstream of said restriction for an independent selection of the oxygen volumes and of the injection times.

A device for metering the oxygen in an elemental analyzer of the gases of the combustion of a sample

• a combustion reactor,
• a sampling device, a sample of material being introduced into the combustion reactor with the sampling device;
• an oxygen feed line for admitting controlled volumes of oxygen into the combustion reactor depending on the sample for the complete combustion thereof,
• a pneumatic circuit, in which the oxygen feed line converges and creates a continuous flow of a carrier gas that is able to carry the oxygen to the reactor and the gases of the combustion through the reactor, then through a gas chromatographic analyzer, and after their separation, into a thermal conductivity detector;
• an electronic apparatus with a data processor for controlling the process;
• a restriction in said oxygen support line;
• an admission valve upstream of said restriction;
• an injection valve downstream of the said restriction;
• a carrier line for a carrier gas, having an admission valve, and being divided by means of a T junction, into a reference line and into a sample line, said oxygen feed line with said restriction meets said sample line;
• an electronic oxygen pressure regulator associated with said oxygen feed line upstream of said restriction;
• an electronic carrier gas pressure regulator on a carrier gas sample line;
• an electronic flow meter, for the measurement of the cater gas flow in the sample line;
• an electronic pressure regulator or an electronic flow regulator for the carrier gas in the reference line;
• and
• a carrier gas outlet valve included in the reference line, for the control of the reference carrier gas, which is also used for purging the sampling device.