GB1141552A - Improvements in fluid energy grinding method and means - Google Patents

Abstract

1,141,552. Drying apparatus. FLUID ENERGY PROCESSING & EQUIPMENT CO. 16 Jan., 1967, No. 2212/67. Heading F4G. [Also in Divisions B1 and B2] To economize in high pressure gas supply to a jet mill 10, transport of the material around the mill is assisted by injection of gas, which may be at relatively low pressure, by subsidiary nozzles 44, 46, Fig. 1, or by recirculation of gas by impellers 312, 314, Fig. 7. The mill 10 comprises an impact chamber 12, compressedgas jets 36, feed devices 38, a first stack 14 connected with the impact chamber and with an arcuate classification section 16, which has outlet conduits 30, 32; a second stack 20 is connected with the classification section and with a recycle chamber 28, which is, in turn, connected with the inlet of the first stack 14. There is thus a circulatory flow path between the first stack, the classification section and the second stack along which the flow of gas and particles is accelerated by injection of gas by nozzles 44, 46. The fine pulverized material leaves via the conduits 30, 32. Gases used may be cool or hot air, steam, products of combustion, inert or reactive gases. Modification may include oppositely-rotating impellers 222, 224, Fig. 5, which not only induce high speed air circulation but may throw particles against each other, causing impact pulverization. The apparatus may be used for grinding coal, coke, metal, synthetic resins, ceramics, instant coffee, tea, cocoa, and for drying and mixing, coating, or facilitating chemical reactions by use of feed channels 48, 50.