We distinguish between screening and classifying by each application or function. Grinding or classifying processes are optimized by a primary screening.
To achieve a screening accuracy of ca. 70-90% linear or circular motion screens are applied for primary screening. The screen is dimensioned corresponding to the throughput capacity and the screen cuts.
The specific screening accuracy and the screening quality are decisive criteria for the dimensioning of the screen surface when size grading the grain. Dependencies of the parameters such as screening behavior, grain shape and bulk density are determined via test series. By means of grain boundary analysis of the oversize grain or undersized grain, the optimum screen netting and screen surface is determined.
Linear motion screens with steep drive component are applied as multi-deck screens for grain size classification, i.e. product distribution on inlet side – grain collector pipes on outlet side. High throughput capacities are reduced to two grain classes. In the inlet area the product is distributed to several screen levels by means of a special distribution device.