H3-VH-22B flender reductores Helical gear boxes H3

Flender/Flender Gear Units/Helical gear boxes H3

concurrent-ow, countercurrent-ow, and mixed-ow systems. The preferred high-temperature continuous grain-drying systemin the United States is the cross-ow dryer (, in which the ow of air is perpendicularto the downward movement of grains. The mixed-ow grain dryers are the most common.The countercurrent-ow drying system where the movements of air and grain are opposite 1 Das and Chakraverty Fig. 2 Different modes of airow in thin-layer grain-drying system: () countercurrent-ow, () concurrent-ow, () cross-ow, and () mixed-ow. is used mainly for cooling grain and drying with in-bin continuous-ow dryers. The system with parallel ow of grain and air (concurrent-ow) is recent design. Figure 2 showsdifferent modes of airow. 4.3.2 Nonmixing Thin-Layer Grain Drying The design of this kind of thin-layerdrying system is very simple where the drying takes place in column of grain held between two screens, and the grain bed moves downwardslowly in plug-ow manner (. The airow is perpendicular to the grain ow. highair velocity can be used, without any chance of blowing out grain. Owing to nonmixing in the drying zone, the grain layer adjacent to the air inlet side is dried by hotter, but less humid, air than that of the exhaust side. However, the mixing occurs at the outlet portsfor the grains. These grains are then either recirculated to the feed hopper of the dryer orconveyed to the tempering bin or storage house. Figure 3 is schematic of nonmixingthin-layerdrying system. 4.3.3 Mixing-Type Thin-Layer Grain Drying The bafe-type and LSU dryers are examples of the mixing-type thin-layerdrying system. The bafe-type dryer design is quite similar to the nonmixing type (see Fig. , but anumber of inclined sheet metal plate bafes are used in the path of grain movement inthe downward direction. The grains are mixed during their downward movement, whilethe hot air ows in crosswise manner. Figure 4 shows the schematic arrangement. Grain-Drying Systems 1 Fig. 3 Nonmixing-type