Conical Screw Dryers. Also called conical mixer dryers, gets their name from their conical shape. The drying chamber is mounted vertically, with the narrow end down. The dryer’s agitator is a long screw conveyor, pivoted at the bottom of the chamber, that rotates, as well as orbits in the vacuum, around the dryer housing, continuously cycling the material to be dried. Some dryers, directed at the pharmaceutical, chemical, and food industries, are provided with a heated screw conveyor to provide more heat exchange area. These dryers are used to process high value, high quality products, and are capable of performing several unit operations such as mixing, drying under vacuum, granulation, heating, cooling, crystallization, reaction, and deodorizing..