Fenghua nitrogen-making is the famous equipment supplier in normal temperature air-separating field. Fenghua Co. has been engaged in researching and developing technical equipment of separating nitrogen from air by pressure swing adsorption(PSA) since 1980s, is one of the earliest enterprises at home which exploits the purification equipment of PSA nitrogen generators. With 20 years special nitrogen-making, technology has innovated and improved constantly. Company's patent of full-automatically hydrogen-adding technology rewritten the history of purification of nitrogen, manual adding hydrogen of domestic, thus it changed the flaw that it can't adjust in time when adding the hydrogen artificial, sometimes it will be too much while sometimes will be lack when adding hydrogen, the content of high purification nitrogen and oxygen is unstable, the consumption of the oxygen is great, and it can't satisfy the request of using nitrogen and lead to the fact that the product quality is unstable.