Improvements in or relating to Methods and Apparatus for Removing Moisture from Organic Materials, Foodstuffs and other Moisture-Containing Substances.

摘要

A method of drying finely-divided material (e.g. food or organic materials) comprises passing the material through a treatment chamber, introducing into the chamber a dehydrating gaseous fluid so that it passes in the same direction as the material, collecting the dried material and recirculating the spent dehydrating fluid in a closed circuit to the treatment chamber. The spent fluid is successively separated from any solid particles entrained thereby, initially cooled in a heat exchange, further cooled to remove by condensation vapours contained in the fluid, initially heated by heat derived from the initial cooling step, further heated to the desired temperature and reintroduced into the treatment chamber. The material may be passed through more than one chamber, the chambers being provided with a common fluid recirculating system or the chambers each being provided with a fluid recirculating system. In the embodiment shown, material from pipe 2 and dehydrating fluid from duct 7 are passed into chamber 1. The dehydrated material is discharged into tank 5 or is recirculated to top of chamber 1. The dehydrating fluid from chamber 1 is passed to cyclones 8, 10 in which any solid material is removed from the fluid. The fluid is then cooled in heat exchanger 11 and treated in dehumidifier 12 in which liquids absorbed from the material in chamber 1 are condensed from the fluid. The condensed liquids are separated in separator 13, the water being discharged through outlet 14 and the other liquids being returned to the treated material. The dehumidified fluid is passed through fog separator 121 and pump 15 is then returned to chamber 1 via heat exchanger 11 in which it is heated by the dehydrating fluid passing to the dehumidifier 12, and heat exchanger 16.