Distance between baffles is generally about 6 inches. The LSU dryer, Figure 3, is a large rectangular solid with a series of inverted V-shaped troughs running across the entire width of the dryer. The rice flows downward past the troughs, but does not fill them. The open space below each trough is used to distribute heated air through the rice. Alternating layers of troughs are used for air supply or air exhaust channels.
Air takes the shortest path from an air supply duct through the grain to an air exhaust duct.
In some designs the air supply troughs are oriented at a right angle to the air exhaust troughs. Rice mixes as it flows around the channels. The LSU type dryer costs significantly more than an equivalent capacity column dryer and because of this, column dryers are the type most commonly installed. Most rice drying operations use column dryers and carefully control the amount of moisture removed per pass and count on moisture equalization between kernels to reduce moisture variability. Rice is subject to lower milling yields if it is dried too quickly.