(1) visual inspection: first checkgas chromatographWhether there is obvious air leakage sound in the system, when there is a large leakage in the gas chromatograph system, it is likely to cause the flow rate not to be adjusted.

(2) leak detection: after hearing the sound of air leakage, it can be positioned step by step according to the direction of the sound. at this time, the occurrence of air leakage can be further determined by applying soap liquid, and the leak can be stopped in time after the cause is found.

(3) Observation of pre-column pressure: Observe the value of the pre-column pressure indicator of the gas chromatograph, and quickly judge whether it is the fault caused by the gas source or the blockage and damage of the internal gas path of the gas chromatograph. If the pre-column pressure is too low (precisely lower than the predetermined pressure value during normal flow operation), then the gas source needs to be checked; if the column front pressure is normal, check the internal gas circuit of the instrument.

(4) High pressure inspection of steel cylinders: After opening the steel cylinder valve of the gas chromatograph, observe the indication of the high pressure gauge. The pressure should be between 1 and 15MPa. If the pressure is below 1MPa, stop using the steel cylinder and ventize. If the pressure value is within the appropriate range, the cylinder pressure is normal.

(5) Check the filter blockage and the pressure regulator valve: slowly unscrew the joint from the outlet of the filter to the inlet of the gas source of the gas chromatograph to observe whether there is a strong airflow running out of the joint. If there is, it means that the filter is not blocked and the pressure regulator valve may have problems. After determining the pressure regulator valve is not out of gas, the valve can be removed and cleaned, which may be caused by the blockage between the valve needle and the valve seat in the pressure regulator valve. If the valve still cannot work normally after cleaning, it is recommended to replace it with a new valve. In the above test, if there is no strong airflow flowing from the unscrewed joint, it is necessary to check the possible blockage before and after the inlet of the gas chromatograph filter. Of course, the blockage of the intermediate pipeline is also possible, but the incidence is very small.