GB631963A - Improvements in cooling apparatus - Google Patents

Abstract

631,963. Cooling granular, pulverulent, and like materials. FULLER CO. Nov. 11, 1946, No. 33498. Convention date, July 3, 1941. [Class 64(ii)] Pulverulent, granular or crushed material is cooled by directing it to an enclosed supply header from which it passes in a horizontal direction in an annular layer between and in contact, on one side, with a surrounding cooled surface and, on the other, with a rotating cylinder filled with a cooling medium and having a diameter substantially greater than the thickness of the annular layer of material, the chamber being maintained under a uniform reduced pressure to remove moisture. Cement as delivered from grinding mills (not shown) is cooled in the apparatus shown in which front and rear headers 11 communicate by means of a connecting casing 12 which is surrounded by a jacket 14 and contains a hollow shaft 21 extending into the headers, both the jacket and shaft communicating with a cooling medium, e.g. water, supply by means of pipes 16, 32 and with outlets 19, 34 respectively. Further the shaft 21 is rotated by a motor 36 and the cement is advanced through the annular space between the casing and shaft by means of screw flights 37 on the latter, the water vapours appearing during treatment being removed by vacuum ducts 52, 55. The diameter of the casing 12 is less than twice that of the hollow shaft 21. An annular guard 38 and double screw flights 39 in the front header keep the cement away from the grease-grooved openings 25 as it is delivered from a feed housing 48. A similar guard and reversed double flight arrangement exists in the rear header, a discharge port from which may communicate with a lower casing 13 in which rotates a shaft similar to the upper shaft 21 but turned end to end and rotated at greater speed. In this way the cement is returned to the lower half of the front header and thence to a discharge hopper 58 connected to a vacuum duct 57. A system is described in which batteries of such cooling units are used in series or some are bye-passed according to requirements.