Annals of Warsaw University of Life Sciences - SGGW.

Methods for evaluation of breaking up of maize chaff separated... 25FIGURE 1. Sieve separator: 1 – base, 2 – gear box, 3 – electric motor, 4 – inverter, 5 – rubber shockabsorber, 6 – frame of ground wheels, 7 – guide of circular section, 8 – housing with linear bearing, 9– sieve, 10 – sieve shoe, 11 – eccentric mechanismeccentric mechanism, which allowed forhorizontal movement of sieves (imitatinghand sifting), consisted of complexmotion: rotary and to-and-fromotion.The separation time of each sampleamounted to 120 s, starting from themoment of stabilization of separator’selectric motor speed. Material particleswere separated on sieves dependingon their length; the sieve parametersand lengths of particles remaining onparticular sieves are given in Table 2. Theshoe movement frequency was equal to2.4 Hz (144 cycles per minute). Rotationalspeed of electric motor was controlled withinverter and monitored on electronic gauge.Upon completion of separation, the massof mixture on each sieve and the bottom(Fig. 2) was weighed on an electronic scalewith accuracy 0.05 g. Besides, the wholegrains remaining on sieves were pickedup and weighed.The measurements for each varietywere repeated 30 times and the resultswere averaged. If material on the firstsieve weighed less than 1% of entire