Nitrogen-making machine is a process in which oxygen and nitrogen are separated by physical means from air to obtain the required gas. Nitrogen machine is based on the principle of pressure swing adsorption, using high-quality carbon molecular sieve as adsorbent, under certain pressure, from the air to produce nitrogen. After purification and drying of Compressed air, pressure adsorption and desorption are carried out in the adsorber. Due to the aerodynamics effect, the diffusion rate of oxygen in the micropores of carbon molecular sieves is much faster than that of nitrogen, which is preferentially adsorbed by carbon molecular sieves and enriched in the gas phase to form the finished nitrogen. Then, by reducing the pressure to normal pressure, the adsorbents remove the adsorbed oxygen and other impurities to achieve regeneration. Generally, two adsorption towers are set up in the system, one tower adsorbs and produces nitrogen, the other tower desorbs and regenerates. The two towers are controlled by PLC program controller to open and close the pneumatic valve, and the two towers are cycled alternately in order to achieve the aim of continuous production of high quality nitrogen. The system consists of a Compressed air purification unit, an air tank, an oxygen nitrogen separator, and a nitrogen buffer tank.According to the press swing adsorption theory,the high quality carbon molecular sieve as the adsorbent, under the certain pressure, carbon molecular sieve has different oxygen/nitrogen adsorption capacity,the oxygen is adsorbed largely by the carbon molecular sieve, and the oxygen and nitrogen is separated. Since the adsorption capacity of the carbon molecular sieve will be changed according to different pressure, once lowering the pressure, the oxygen will be desorbed from the carbon molecular sieve. Thus, the carbon molecular sieve is regenerated and can be recyled. We use two adsorption towers, one adsorb the oxygen to generate nitrogen, one desorb the oxygen to regenerate the carbon molecular sieve, cycle and alternation,on the basis of PLC automatic process system to control the pneumatic valve open and colse, thus to get the high quliaty nitrogen continuously.1. The press swing adsorption theory is very stable and reliable. 2. Purity and flow rate can be adjusted in a certain range. 3. Resonable inner structure, keep the balance airflow, alleviate the air high speed impact 4. Unique molecular sieve protective measure, extend the working life of the carbon molecular sieve 5. Easy installation 6. Process automation and easy operation.