mo's CORNER: Part 17: What are the key characteristics of a hot-air dryer? mo explains: Possibilities and limitations of hot-air dryers

摘要

Hot-air dryers are suited to preheating and drying non-hygroscopic or slightly hygroscopic plastics. These attractively-priced systems use ambient air to dry plastics by carrying the surface moisture away, but without the use of desiccants. Use of ambient air means that drying results will vary depending on prevailing weather conditions. Hot-air dryers operate within an open cycle. Ambient air is drawn through a filter, heated, and then passed through the resin granulate in the drying hopper before being vented to the factory floor. Some dryers feature a changeover valve to allow partial recirculation of the humid air. Drying temperature and air flow rate can be controlled via the heater/blower unit. Hot-air dryers transfer heat via convection.