drying of particulate materials , such as wood chips for the manufacture of oriented structural board , as well as bark , and the like . the method is characterized by advancing wafers in random array and superposed and without contact above a planar surface ; forcing heated air upwardly through spaced apart holes defined in the stationary planar surface and through the random array of advancing wafers , while evacuating heated air and accumulated moisture above the advancing wafers . the method is distinguished by lateral shielding during forcing of heated air above the planar surface , so as to inhibit &# 34 ; blow - holes &# 34 ; among the drying wafers .