Bevel-helical speed reduction gearbox B4 D Options for operation Shaft seals Labyrinth B4-DH-11B

Flender/Flender Gear Units/Bevel-helical speed reduction gearbox B4

tting, rather than keeping the bran akes large,is intended. This is accomplished through positioning the grinding rolls in sharp-to-sharpdisposition. 5.5.2 Grading System The longer break system is designed to generate relatively higher percentage of granular material which, obviously, would have to be graded next. Therefore, the requirement forelaborate grading of released endosperm particles is logical. The grading operation facili-tates their separation into numerous narrow-range bands of particle size. This is essential for effective purication action. Effective purication (stratication) can be attained only if material fed to the purier falls within narrow particle size range. 5.5.3 Purication SystemThe purication system is very comprehensive in all durum wheat mills. In most mills the purication function is divided into two stages: primary purication and secondarypurication. In the primary purication, the coarse granular endosperm particles from the break system after being graded, are puried. Puried streams would contain pure endo- sperm particles and composite particles of endosperm with bran, germ, or both attachedto it. These streams would be then directed to the sizing system. The secondary puricationsystem is fed by the granular endosperm material after it has been gently ground for size Grain-Milling Operations 3 reduction and to detach the bran and germ from the endosperm by the sizing system. The puried semolina of appropriate size, and free of any bran specks, leaves the secondarypurication system and is the nished product. The overall purication system can beconsidered the most important feature in the durum-milling process. 5.5.4 Sizing System The purpose of the sizing system is to grind lightly to obtain appropriate granulation of the semolina as well as to scratch off bran and germ fragments attached to the endosperm in the composite particles. Finely corrugated rolls ranging from 8 to 1 corrugations per centimeter for the rst through sixth siz