Since the air contains a certain amount of water and oil vapor, after passing through the compressor, if it is not subjected to strict air purification treatment, the oil vapor is easily adsorbed by the carbon/zeolite molecular sieve, and it is difficult to release, and the pore size of the carbon/zeolite molecular sieve in the nitrogen/oxygen generator is filled, resulting in bad performance of nitrogen/oxygen generator. Carbon/zeolite molecular sieve which is poisoned is damaged & invalid, and can’t be regenerated. Therefore, it is an essential to ensure the service life of the carbon/zeolite molecular sieve of the nitrogen/oxygen generator before the compressed air enters the adsorption tower of the nitrogen/oxygen generator. Although the water is not fatal to the nitrogen molecular sieve of the nitrogen generator, it will increase the adsorption “load” of the carbon molecular sieve of the nitrogen generator, which affects the ability of the nitrogen generator to adsorb O2 and CO2.