Pressure swing adsorption uses high-quality carbon molecular sieve as the adsorbent. Under a certain pressure, the diffusion rate of oxygen molecules in the air is greater than the diffusion rate of nitrogen molecules and the inherent physical characteristics of carbon sieve. Nitrogen molecules are used. Oxygen molecules pass through carbon. The difference in the adsorption capacity of molecular sieve is controlled by the variable program to control the opening and closing of the pneumatic valve to achieve the alternating cycle of the A and B towers. Pressure adsorption. Decompression desorption process completes the separation of oxygen and nitrogen to obtain the required purity Nitrogen.