Urea crusher - generally there are cage type and roller type. Cage-type urea crusher can crush all kinds of single fertilizers with water content below 40%, especially for materials with high hardness. The machine is designed according to the principle of impact crushing. The two groups of cages inside and outside rotate at high speed, and the materials are crushed by the impact of cages from inside to outside. The counter-roll crusher is mainly composed of the counter-roll wheel, the roller supporting bearing, the pressing and adjusting device and the driving device. The counter-roll crusher uses the backlog of two rollers to crush the material. The particle size of crushing can be adjusted by adjusting the gap between the two rollers. Roller crusher is suitable for crushing brittle materials with small water content. The cage crusher and the roller crusher have the characteristics of simple structure, high crushing efficiency, good sealing performance, smooth operation, easy cleaning and maintenance, etc. The roller crusher also has the characteristics of low noise and low energy consumption.