Patent ID: 6993857

Claim:
Milling and drying apparatus incorporating at least one cyclone, said cyclone comprising: an upper cylindrical portion which opens into the wider end of a lower frustro-conical portion, with the longitudinal axes of said upper and lower portions aligned; a primary air inlet into the cyclone arranged such that the inlet air is substantially tangential to the circumference of the cyclone; an exhaust outlet at or adjacent the top of the cylindrical portion; a control valve associated with said exhaust outlet and capable of partially or completely shutting off said exhaust outlet; a secondary air inlet associated with the narrow end of the frustro-conical portion and provided with an air flow stabilising device which is adapted to admit a stream of air substantially along the longitudinal axis of the cyclone; a product inlet device arranged to supply product to be processed in the cyclone into the air supplied to either the primary or the secondary air inlets; an air supply means connected to the primary air inlet and to the secondary air inlet; air heating means adapted to heat air supplied to, and/or air supplied from, said air supply means; means for recycling all or part of the air exhausted from the cyclone through the exhaust outlet to said air supply means, wherein said means for recycling incorporates at least one monitor for measuring the humidity and the temperature of the air exhausted from the cyclone, and a valve for adjusting the proportion of the exhaust air directed to the air supply means in response to the monitor readings, and means for withdrawing processed product from the cyclone.