Environment-friendly graded combined type frequency-variable screening plant

The invention discloses an environment-friendly graded combined type frequency-variable screening plant. The screening plant comprises a main rack, a screening device, a power device and an auxiliary device, wherein the screening device, the power device and the auxiliary device are arranged on the main rack. The screening device is composed of a dustproof hopper, a screening sieve, screening plates which are obliquely arranged at a certain angle and are in different hole diameters, and a dustproof discharging hopper. An adjustable frequency converter and a frequency-variable motor are adopted and are combined with a speed reducer. A screening system reciprocates through a transmission wheel with a crank connection rod hinged to a wheel track. An automatic conveying belt is used for continuous feeding, and comprehensive dustproof airtight measures are taken. Screening frequency is controlled according to characteristics of raw materials and production requirements, building raw materials in different particle