Study and Computer Aided Design of Cross Flow Grain Dryer With Reversing Air Flow

Crossflow grain dryer is one of the earliest designed dryers and used for longer time, and it is used widely in the world nowadays because it has good characteristics， such as simple structure, low price, less trouble and long service life. But it has a big defect that is the moisture between the inner and the outer part of grain is different while the grain is drying, so the moisture of dried grain is not enough uniform. A crossflow dryer with two columns was designed in recent years in order to overcome the defect. A turn flow device was equipped in the drying section, the inner layer of grain flows into the outside and the outer flows into the inside when the grain passes through the device, thus the all grain can be heated by hotter air. Because of the structure of the device, the grain layer passing the device becomes thinner, and the grain is blocked up easily when it pass through the cross pipes, especially there are more moisture and more impurities in th grain. Moreover the turn flow device takes more room. Ventilating chamber is equipped between the columns, so it is as high as the columns, which makes the efficiency decrease. Although it has some defects, the cross flow dryer has obvious advantages. On the basis of deep research about the crossflow dryer, a new style crossflow grain dryer was　designed, that is multitrough， multistage， crossflow grain dryer with reversing air flow. The reversing ventilation can be realized by changing the direction of hot air flow in the dryer body， and gives better design with computer grain drying simulated program (CGDSP)．