4. Workikng Principle The clean, dried compressed air enters into the variable-pressure adsorption nitrogen generator, and the oxygen molecule in the compressed air will be absorbed by a carbon molecular sieve, to obtain the nitrogen in the required purity. The absorption capacity of the carbon molecule sieve for nitrogen and oxygen differs under different pressure. One variable-pressure adsorption nitrogen generator is equipped with two adsorption towers, one begins the adsorption while the other reaches balance and begins regeneration. The two adsorption towers alternatively works to create the continuous nitrogen flow.