Hollow fiber ultrafiltration membrane
is one of the most natured and advanced ultrafiltration technologies. The outer diameter of the membrane is 0.4-0.6mm, inside diameter is 0.3-0.5mm. The micropores distribute around the wall of the membrane. The entrapping molecular weight scale is about several thousand to ten thousand. The water flow from the outside of the membrane to the inside, it is outer pressure type. In adverse, it is inside pressure type. The ultrafiltration is a dynamic process, and the entrapping matter can be drained out following the concentration water.