Filtration is the process of separating solid particles from fluid. The basic principle is: under the action of pressure difference, the solid-liquid and gas-solid two-phase mixture is forced to pass through the porous medium, and the solid particles are trapped on the medium to achieve liquid and solid, The purpose of gas and solid separation. In addition to filtration, there are several common methods to achieve solid-liquid separation in industry, such as sedimentation, hydrocyclone, and centrifugal separation. Generally speaking, filtration is more economical than centrifugal separation and other methods, but the solid product obtained has a high moisture content. Settling and hydrodynamic separation are more convenient and feasible than filtration, but the separation efficiency is not as good as filtration. For fine particle suspension or solid content Less suspension, using pressure filtration.