Wet material enter the inner cylinder, propelled through the system via a hot gas air stream. The material is continuously lifted by the cylinder flights and showered through the concurrent stream of hot gases. The three full-length interlocked concentric cylinders rotate together design for the highest velocity in the inner-pass. As lighter particles quickly lose 60% of their moisture and move out of the cylinder, heavier/denser particles are retained until they also lose 60% of their moisture.

Particles graduate to the next cylinder only when they have shed enough of their moisture to be carried out. Progressively larger diameters of the cylinders cause the velocity to decrease with each subsequent pass. In this section, the partially evaporated particles are handled more gently, again only graduating to the next pass when they have shed the proper amount of moisture.

Because of the earlier retention time in the first two passes, material is relatively uniform by the time it makes it into the gentle third pass. This means the product is guarded against over-drying or under-drying and ensures the optimum use of heat while producing a consistently high quality end product.