The Nesco / American Harvest Converge-a-Flow Illustrated

All NESCO food dehydrators feature the patented Converge-a-Flow® method of air circulation. In many units you will find all power components located in the top of the unit, which eliminates any possibility of juices dripping down upon the electric circuitry. The fan moves air vertically as well as horizontally across each tray in the drying chamber, converging in the center. The air flow is well regulated and efficienlty maintained, no matter how many trays are being used, up to the dehydrator's recommended maximum. It automatically adjusts to your needs, assuring constant, even and effective drying. There is no need for tray rotation, and no doubling or tripling of drying time when you increase the number of trays.

This is only one of the reasons, although it's an important reason, for Nesco taking such pride in its line of food dehydration products.  It does help to show why they say with confidence, "Whether you're a beginner or an experienced "pro", making beef jerky, drying fruits, vegetables, herbs, or flowers, NESCO®/American Harvest® offers the best units available."