Process and apparatus for mixing or homogenising powdered material

791,266. Mixing powdered materials. KLINGER, M. Jun., KLINGER, M., and KLINGER, E. [trading as KLINGER HOMM-GES.]. April 24, 1956, No. 12538/56. Class 86 Dry mixing and homogenization of cement, lime, and like powdered material, in large capacity containers is effected by compressed air which is introduced into the bottom of the container at different pressures over different concentric zones. Fig. 1 shows a container 1 of from 500-1000 tons capacity which is provided with a filling pipe 2, vent 3 and a perforated hollow bottom 5 divided into a central and four concentric chambers a...e to which air is supplied, respectively, through pipes 13a..13e associated with distributing rings 12b...12e coupled to a compressed air main 6 through valves 7...11. In operation, the material in the container is first "loosened up" by supplying air at a pressure of about 2.2 atmospheres absolute to the central chamber a, then to the chamber b also, and finally to the other chambers inturn; mixing is now effected by supplying air at a pressure of about 1.8 atmospheres absolute to, say, the chambers a, c, e and lower pressure air at 1.2 atmospheres to the chambers b, d, the high and low pressure connections being reversed after a specific time interval varying from a few minutes to about an hour. Cooling of the material during mixing may be effected by air from a separate source which is introduced into the container through upstanding perforated pipes 14. Fig. 3 (not shown).