Drying product contg. volatile constituent - by heating product successively with part of vapours previously compressed and part previously superheated by auxiliary fluid

摘要

Drying comprises heating the product by a part of the vapours from the product previously compressed and then heating the product by contact of the latter with a part of the vapours previously superheated by exchange of heat with an auxiliary fluid. An appts. comprises an enclosure, means of charging product to the enclosure, and first and second vapour circuits. The first opens at one or other of its ends into the enclosure and into a receiver for recovery of condensate from teh vapours. This circuit includes a compressor and means of heating the product from the heat of the vapours in the circuit. The second circuit has the inlet and outlet respectively connected to the enclosure and is sepd. from the first circuit. It includes means of putting the vapours into circulation and means of exchanging heat between them and an auxiliary fluid. Used in the recovery of alcoholic vapours from the skins of grapes after the last pressing and subsequent drying of the latter. The efficiency of desorption attained is greater than that obtd. in existing methods by mixing of the product and the air surrounding it, as the specific heat of the vapour is double that of air and the volatile constituents have a greater affinity to their vapours than air.