The main reason for the decrease of nitrogen purity is that in the process of nitrogen production:

1. The adsorption pressure of liquid nitrogen is unstable. First, the adsorption pressure is too high., It exceeds 0.8MPa. Second, the adsorption pressure is too low, lower than 0.6MPa.

2. Too much water and oil in the gas source.

3. There is air leakage at the interface of the air outlet part.

4. Too much air intake means that the pressure rises too fast.

5. Molecular sieve in absorption tower is poisoned.

The following solutions can be taken:

1. Reduce / increase the intake pressure to the required range.

2. A storage tank and an oil-water separator are added in front of the air inlet of the nitrogen generator.

3. Take out the air outlet interface and plug it.

4. Adjust the inlet valve of the nitrogen generator to reduce the air intake.

5. Replace the molecular sieve in the adsorption tower.