GB730491A - Desolventizer and toaster - Google Patents

Abstract

<PICT:0730491/III/1> <PICT:0730491/III/2> Solid organic materials forming the residue from a solvent extraction process, e.g. the flaked solids remaining after the extraction of soya beans with hexane and like solvents, are freed from residual solvent and toasted to give a nutritious meal, by passing the solids downwardly through a series of superposed chambers in countercurrent to steam and the solvent vapours. The solids are heated in the initial zones to a temperature above the boiling point of the solvent but below that of water and in the final zone to a temperature above the boiling point of water. The chambers are heated by circulating steam through their jacketed walls and hollow floors which latter have separate vents for passage of vapours and solids which are circulated by rotary stirrers. The superposed chambers A, B, C, D (Fig. 1) are formed by a jacketed wall 22 and hollow floors 23. Each chamber has a hinged door 25 provided with a thermometer 27. The upper chamber has a cover 28 provided with sight glass 29 and tubular elbow 33 connecting to a condenser. Each floor (Fig. 2) is provided with a vapour passage 54 covered by a perforated plate and a solid exit 56 controlled by a gate 56a opened by external arms connected to floats 56b. Chamber D has an outlet 62 leading to a condensate drain. Each chamber is provided with stirrer arms 41 having bevelled leading edges 43 and a perforated steam pipe 50 extending along the trailing edge. Rotation of the scrapers and supply of steam to the pipes 50 is effected through a hollow shaft 34 passing through the whole structure. The shaft is provided with stuffing-box closures 39 and a head 40 connected to each stirring arm 41. It is also formed with a passage 45 communicating in each chamber with a pipe 46 joined to the spray pipe 50 on the stirrer 41 and thus afford means for supplying steam to the pipes 50.