GB565476A - A process and apparatus for drying substances - Google Patents

Abstract

565,476. Spray evaporators. BERK & CO., Ltd., F. W., SIX, G. J., and SIX, C. G. Jan. 27, 1943, No. 1381. [Class 32] Dilute solutions, vegetable pulps, clay slurries and heat sensitive materials, e.g. white precipitate of mercury (HgNH2Cl), corrosive solutions, e.g. cupric chloride, are dried by spraying the solution &c. by means of a compressed gas, e.g. air, nitrogen, carbon dioxide, &c., to form an upwardly directed non-rotating cylindrical stream, which is surrounded by an upwardly directed stream of hot gas, e.g. air free from longitudinal vortices, the velocity of the sprayed solution being much greater than the velocity of the surrounding stream of hot gas. Nozzle speeds of 100-150 ft. per sec. for the surrounding air stream and from 600-2,400 ft. per sec. for the inner stream are specified. The non- rotating blast is obtained by placing thin strengthening blades or vanes in the conduit supplied with hot air from a fan. The solution or slurry is fed by a roller pump through a pipe 9 and injected upwardly by compressed air from a pipe 10 into a conduit 8 through which the surrounding stream of hot air is pumped. The conduit, Fig. 3, is provided with radial blades 15 mounted on a cylindrical ring 16 and a pipe 17 which receives the pipe 10. The streams are sprayed upwardly into a duct bag 1 mounted on a wooden frame 3 supported by a rope 4. The dried powder is removed through hoppers 6. A hydrometer 7 is provided to determine the humidity of the air, and the surface area of the filter bag is maintained in determined relation to the volume of damp air leaving the bag.