2 3 3 T he basic c onc ept of the MMD Siz er , is the use of t w o r ot ors with lar ge t eeth, on small diamet er shaf ts , dr iv en a t a lo w speed b y a dir ec t high t or que dr iv e sy st em. T his desig n pr oduc es thr ee major pr inciples which all in t er ac t when br eak ing ma t er ials using Siz er T echnolo gy . T he unique pr inciples ar e; T he T hr ee -S tage Br eak ing A c tion, T he R ota ting S cr een Ef ec t , and T he D eep S cr oll T ooth P a tt er n. I nitially , the ma t er ial is g r ipped b y the leading fac es of opposed r ot or t eeth. T hese subjec t the r ock t o multiple poin t loading , in - ducing str ess in t o the ma t er ial t o e xploit an y na tur al w eak nesses . A t the sec ond stage , ma t er ial is br oken in t ension b y being sub - jec t ed t o a thr ee poin t loading , applied bet w een the fr on t t ooth fac es on one r ot or , and r ear t ooth fac es on the other r ot or . A n y lumps of ma t er ial tha t still r emain o v ersiz e , ar e br oken as the r ot ors chop thr ough the fx ed t eeth of the br eaker bar , ther eb y achieving a thr ee dimensional c on tr olled pr oduc t siz e . The Principles of SIZER TECHNOL OG Y The R ot ating Screen Ef f ect The Deep Scr oll T ooth P attern T he in t er lac ed t oothed r ot or desig n allo w s fr ee fo wing undersiz e ma t er ial t o pass thr ough the c on tinuously chang ing gaps gener a t ed b y the r ela tiv ely slo w mo ving shaf ts . T he deep scr oll c on v ey s the lar ger ma t er ial t o one end of the machine and helps t o spr ead the f eed acr oss the full length of the r ot ors . T his f ea tur e can also be used t o r ejec t o v ersiz e ma t er ial fr om the machine . The Three-S t age Breaking Action 1