Ultrafiltration is a system device that takes pressure as the driving force and uses different pore sizes of ultrafiltration membrane to separate impurities, bacteria, colloids, suspended solids, proteins and other substances in the liquid, so that the molecular substances dissolved in water can be retained, such as calcium, magnesium, silicon and metal ions, so as to obtain finished water. It is usually used for the preparation of mineral water, the separation of solvents, the reuse of reclaimed water and the re-treatment of RO. Widely used in light textile, chemical, medical, food, environmental protection, electronics and other industries.