(1) Installation of pressure reducing valve

Somegas chromatographComes with pressure relief valve, if you do not need to buy. The dioxygen-hydrogen pressure reducing valve is respectively installed on nitrogen, air and hydrogen cylinders (note that the thread of the hydrogen pressure reducing valve is reversed and the attached O-type plastic gasket is added to the interface for sealing). After tightening the nut, close the adjusting handle of the gas chromatograph pressure reducing valve (I. e. unscrew) and open the high pressure valve of the steel cylinder. At this time, the pressure gauge of the pressure reducing valve should have instructions. After the high-pressure valve is closed, the indicating pressure should not drop, otherwise there should be leakage, which should be eliminated in time (sealed with gasket or raw material tape). Sometimes the high pressure valve will leak, pay attention. Then turn the gas chromatograph adjustment handle to discharge the remaining gas.

(2) External gas connection mode

The gas in the gas cylinder is introduced into the gas chromatograph. Some use stainless steel pipes (φ2 × 0.5mm) and some use pressure-resistant plastic pipes (φ3 × 0.5mm). The plastic pipes are easy to operate, so the gas chromatograph generally uses plastic pipes. If plastic pipes are used, the joints shall be provided with stainless steel liner (φ2 × 20mm) and some plastic seals. The length of the plastic tubing from the cylinder to the gas chromatograph depends on the need. The time should not be too long, and then use a plastic pipe to connect the air source to the instrument (air inlet).

(3) Leak detection of external gas path

Close the valve knobs of carrier gas, hydrogen and air on the airway plate of the main engine of the gas chromatograph, then open the pressure valve of each steel cylinder to adjust the output of the low pressure gauge on the pressure reducing valve to make the pressure of carrier gas 0.35~0.6Mpa (about 3.5~6.0kg/cm3) and the hydrogen pressure 0.2~0.35 Mpa, then close the high pressure valve. The instrument indication value shall not drop. If it drops, it indicates that there is leakage in the gas circuit connected to the gas chromatograph, which shall be eliminated.