Mitchell Thermo Venturi Dryers (also known as Flash Dryers or Pneumatic Dryers) are supplied for continuous drying of powders and granules which can be readily dispersed and conveyed in a hot air stream.
The wet material is fed into the base of a vertical drying duct, dispersed in a high velocity air-stream, dried and simultaneously conveyed to product collection. Material residence times are no more than a few seconds. This, together with the rapid evaporation, keeps the product cool enabling thermo-sensitive materials to be handled at elevated temperatures and provides a very efficient system with low operating costs. Hot air is supplied into the base of the drying column. The heating and the inclusion of suitable pre-treatment equipment, together with recycling of the product, enables more difficult materials to be handled – including some liquids.
Product collection can incorporate cyclones or bag collectors and, for secondary recovery, electrostatic precipitators or wet scrubbers. Systems are designed to meet appropriate emission standards.
Cooling of the product and exhaust gas heat recovery are available as options.
If required, Mitchell Thermo Venturi Dryers can be situated outdoors with only the feeding and product collection points indoors. These units are supplied complete with all the necessary control equipment and safety features. Capacities range from pilot scale to tonnage plants.
Typical applications cover all process industries drying a wide range of chemical, food and mineral products. Examples are: Wheat and maize starch, confectionery, wheat flour moulding starch, aspirin, distillers and brewers grains, mineral concentrates and calcium carbonate.