B4-KV-10-D l supply systemgear unit connection can also be d Bevel-helical speed reducers B4

Flender/Flender Gear Units/Bevel-helical speed reducers B4

vapor-lock that occurs within the capillary structure causing breaksin liquid-lled capillaries. This phenomenon can cause departure from the classic drying curve [.., no constant-rate drying may appear under intense-drying conditions, but may do so under milder-drying conditions (Zaharchuk, ]. 1.4 Drying Kinetics of Grains Without exception grains are dried in convection (direct-type) dryers using heated air as the drying medium. Use of conduction, radiation, or dielectric heating is negligible in practice. Most dryers are thus basically packed-bed uid-type, with heated drying air per- colating through the bed, which may be stationary or moving under gravity. Use of uid-ization, spouting, vibration, agitation, or other, is possible; but not often useful in practice. The direction of the airow may be upward, downward, or in the cross-ow direction relative to stationary or moving bed. Often internals are placed within the bed of grainsto ensure better ow of the grains and more uniform air distribution to avoid wet and hot spots. Except when harvested in wet season, most of the drying of grains occurs in the following rate period. The internal moisture diffusion model adequately describes the fall-ing rate. Newtons coolinglaw-type model is also applied, for example: dt/H1k(/H1X*) or, separating variables and integrating ()/H1X* Xi/H1X*/H1exp(kt) 1 Mujumdar and Beke where Xiis the initial dry-basis moisture content of the grain. modication of the forego- ing equation that gives an additional tting parameter nis the so-called Page equation: ()/H1X* Xi/H1X*/H1exp(/H1ktn) where kandnare determined empirically. The foregoing models are often referred to as thin-layer models, as they assume no external resistance to moisture transfer. In practice, deep beds are used in which thedrying conditions (.., temperature of grain and air as well as air humidity) change contin-uously. Hence, in modeling deep beds it is necessary to account for changes in external conditions eve