Wood chip screening machine The screening machine is divided into fixed screen and movable screen, and the movable screen is divided into rotary screen and vibrating screen. Most fixed screens are installed above the inlet of the crusher by grate to prevent oversized materials from falling in. Rotating screens are mostly made of plate screens folded into polygonal or circular cylinders, which are simple in structure and long in life, but low in productivity, bulky and bulky in body, and are rarely used at present. Vibrating screen includes eccentric ring moving screen, inertial vibrating screen and resonance screen. The common feature is that the screen surface vibrates with high frequency and small amplitude, which makes the materials on the screen surface separate. The screen hole is not easy to block, the screening efficiency is high, the structure is simple, the weight is light, the power consumption is low, and the viscous or wet materials can be screened, which is widely used; When the raw materials contain clay, silt or other impurities, they can also be washed with pressure water on the screening machine for wet screening. ① The amplitude of eccentric ring movable screen does not change with the amount of material on the screen, and is suitable for the first coarse screen. The mesh size is generally 13~100mm, up to 100~250mm. The maximum feed particle size can reach 300 mm. ② Inertial vibrating screen has single axis and double axis. The movement of its vibrating system is related to the weight of materials and the spring stiffness. Therefore, the increase or decrease of materials on the screen surface directly affects the amplitude. It is suitable for occasions where the feed volume and particle size change little, and is often used for the second screening of aggregates. The mesh size is 0.5~100mm, and the maximum feed particle size is 100~500mm. ③ The screen box of the resonance screen works under the resonance condition. It can work continuously only by supplying energy to overcome the screening motion damping, and consumes less power. It is suitable for screening medium and fine stones. The mesh size is 0.5~80mm, and the maximum feed particle size is 100mm.