Relative to the pressure homogenizer, colloid mill is a centrifugal device, its advantages are simple structure, easy equipment maintenance, suit for higher viscosity materials and larger particles of the material. Its main drawback is also determined by its structure. First of all, as a result of centrifugal movement, the flow is not constant, corresponding to the same viscosity of the material flow rate changes. For example, the same equipment, in dealing with viscous lacquer materials and thin dairy fluid, the flow rate can be more than 10 times; followed by the surface easier to wear, and wear, the refining effect will be significantly reduced.