NMI series membrane separation nitrogen generator is composed of one or more membrane separators. When the clean compressed air passes through the polymer membrane, due to the difference in the solubility and diffusion coefficient of various gases in the membrane, the relative permeability of different gases in the membrane is caused rates are different.When the pressurized purified air is used as the gas source, the gas with relatively fast permeability, such as water, hydrogen, oxygen, carbon dioxide, etc., is enriched on the side of the membrane after passing through the membrane. while the gas with relatively slow permeation rate, gases such as nitrogen and argon are enriched on the retentate side of the membrane, thereby achieving the effect of separating the mixed gas. Nitrogen and other inert gases are enriched into high-purity gases for production use, while the enriched oxygen-enriched air on the permeate side is evacuated as waste gas. The nitrogen membrane uses this principle to separate nitrogen and oxygen in the air through multiple bundles of semi-permeable hollow fiber filaments made of polymer materials.