(1) Installation of pressure reducing valve

Yesgas chromatographRandom with pressure reducing valve, if not to buy. Two oxygen and one hydrogen pressure reducing valve are used. The two oxygen pressure reducing valves and one hydrogen pressure reducing valve are respectively installed on nitrogen, air and hydrogen steel cylinders (note that the thread of the hydrogen pressure reducing valve is reversed, and the attached O-shaped plastic gasket is added at the interface for sealing). After tightening the screw cap, close the adjusting handle of the gas chromatograph pressure reducing valve (I .e. loosen), and open the high pressure valve of the steel cylinder. At this time, the pressure reducing valve should have instructions, after closing the high-pressure valve, the indicating pressure should not drop, otherwise there is a leak, should be promptly excluded (with gasket or raw material with seal), sometimes the high-pressure valve will leak, should pay attention. Then turn the adjusting handle of the gas chromatograph to discharge the residual gas.

(2) External gas path connection method

The gas in the cylinder is introduced into the gas chromatograph, some of which use stainless steel tubes (φ2 × 0.5mm) and some of which use pressure-resistant plastic tubes (φ3 × 0.5mm). The plastic tubes are easy to operate, so the gas chromatograph generally uses plastic tubes. If plastic pipe is used, stainless steel liner (φ2 × 20mm) and some plastic materials for sealing are required at the joint. The length of plastic pipe from steel cylinder to gas chromatograph depends on the need and should not be too long. Then the gas source and instrument (gas inlet) are connected by plastic pipe.

(3) Leak detection of external gas path

Close the valve knobs for carrying gas, hydrogen and air on the gas circuit panel of the main engine of the gas chromatograph, then open the high-pressure valves of various steel cylinders, adjust the output pressure of the low-pressure gauge on the pressure reducing valve, so that the air pressure of the carrier gas is 0.35~0.6Mpa (about 3.5~6.0kg/cm3) and the hydrogen pressure is 0.2~0.35 Mpa, then close the high-pressure valve. At this time, the indicated value of the low-pressure gauge on the pressure reducing valve should not drop, it means that there is a leak in the gas circuit connecting the gas chromatograph and should be eliminated.