| 摘要 |
813,552. Making coated pellets. G. & A. LABORATORIES Inc. Aug. 28, 1956 [Sept. 21, 1955], No. 26319/56. Class 87(2). A method of making coated pellets comprises rotating a mass of finely divided coating material, e.g. clay particles, by means of blades attached to a horizontal shaft, adjusting the speed of rotation of the shaft so that the top surface of the mass is above the axis of rotation but below the top arc of travel of the blades, distributing liquid droplets, of molten material e.g. rosin, over the mass and maintaining the temperature of the mass below the solidification point of the droplets to form coated pellets. The liquid droplets and the coating may be of the same material. Rosin, clay, thermoplastic resins, asphalts, waxes and ammonium nitrate are mentioned. The method may be performed in an open topped container 10 having a rotating shaft 11 with spiral blades 12, an outlet 15 with a valve 16 leading to a further container 22, and a liquid supply pipe 17 with nozzles 18. The container 22 has an inclined screen 19 leading to a receptacle 24 and an outlet 25 leading to two screw conveyers 26, 28 arranged to discharge into a funnel 29 on the first container 10. In operation, the container 10 is loaded with a mass of particles 30 and the shaft 12 rotated, thus resulting in a "beating" of the mass 30 by the blades 12 and causing air to be trapped in the mass and the mass to expand so that its top level is between the axis of the shaft 11 and the top arc of rotation of the outer edges of the blades 12. Liquid droplets emitted from the nozzles 18 fall onto the agitated mass, rotate with it and become coated with a film of the particles. Opening of the valve 16 causes the pellets to fall onto the screen 19 from whence they are removed to the receptacle 24, excess particles passing through the screen and being returned to the container 10 by the screw conveyers 26, 28. Specification 812,166 [Group III] is referred to. |
