Mixing equipment is widely used in various industries and daily life, its use is: ① a variety of materials with a uniform mixture. For example, cement, sand, gravel and water mixed into a concrete wet material. ② increase the contact surface area of the material to promote chemical reactions. For example, gas-liquid phase catalytic reaction, it is necessary to make solid powder catalyst or liquid catalyst (the density is different from the reaction of the liquid) in the liquid evenly suspended, and the formation of small gas bubbles in the liquid evenly dispersed. ③ accelerate the physical changes. Such as the addition of solvent solute, through the role of mixing machinery can accelerate the dissolution of mixing. Commonly used mixing machinery is divided into gas and low viscosity liquid mixer, medium and high viscosity liquid and paste mixing machinery, thermoplastic material mixing machine powder and granular solid material mixing machinery 4 categories.