GB961030A - Process of granulating difficultly dispersible materials into readily dispersible form, and products obtained thereby - Google Patents

Abstract

961,030. Granulating-machines. MOTOMCO Inc. June 16, 1960 [June 16, 1959], No. 21250/60. Addition to 926,409. Heading B5A. [Also in Division B1] A readily dispersible, granular, free-flowing and substantially dust-free material is obtained from a solid, finely divided material when the latter is fluidized and conveyed on a vibrating inclined surface while being sprayed with a swelling agent, new surfaces of the particles continuously being exposed to the spray by the vibration which also separates the treated particles from the untreated ones, the former being conveyed downwardly on the inclined vibrating surface while the latter are conveyed upwardly to be subsequently exposed to spraying. In one form of apparatus (Fig. 1), finely divided material 12 is fed through a hopper 10 to the trough 1, the bottom plate 5 of which is inclined at an angle of 10 degrees to 60 degrees, preferably 15 degrees to 35 degrees, with the horizontal and is vibrated by a device 8, such as an electromagnetic, pneumatic, spring or eccentric-operated vibrator. The upper and major portion of the plate 5 is unsupported, the ratio of supported to unsupported surface being, for instance, 1:1“ to 1: 2. The vibration rate is 1000 to 5000, preferably 3000 to 4000, impulses per min. at strokes of <SP>1</SP>/ 125 to # inch, preferably <SP>1</SP>/ 64 to <SP>1</SP>/ 16 inch. A spraying device 11 impinges a spray or mist of a desired swelling agent on the material 12 and the granulated material is removed through outlet 4. At least the lower portion of the bottom plate 5 may be heated, e.g. by the use of infra-red radiation. It is advantageous to incline the vibrating device 8 so that the treated particles are repeatedly thrown upwardly and forwardly in synchronism with the pulsations. In a modified apparatus (Fig. 5), the trough 1 is provided with an inclined shoot 23 so that untreated material removed along with the granulated material flows back into the vibrating trough, thus increasing the efficiency of granulation to essentially 100% per pass. The angle of inclination of the shoot 23 should be less than that of the trough 1, preferably 2 degrees to 5 degrees less.