GB212888A - Improvements in or relating to pulverisers - Google Patents

Abstract

212,888. International Combustion Engineering Corporation, (Assignees of Bell, J. E.). March 15, 1923, [Convention date]. Impact pulverizers. - A pulverizer for coal &c. comprises a hollow impeller which is rotated at high speed and has an open throat leading to a series of impeller blades adapted to pulverize the material fed through the throat and to throw the pul. verized material progres - sively without retrogression to a receiver placed adjacent the periphery of the impeller. As shown in Figs. 1, 2, and 3, the coal passes from a bin by a pipe 7 to a casing 8 containing a feed-screw 9 which delivers it into a throat 10 leading to the throat 11 of a runner or impeller 12 mounted within a casing 13 and on a rotary shaft 14 which may be driven by a steam turbine B. The impeller has long blades 15 and short blades 16; and adjustable impact-plates 16<1> are arranged nearly at right-angles to the line of flight of the particles discharged from the impeller and inclined slightly so that the pulverized coal after impact is. carried away 'from the blades into the peripheral receiving-chamber 17 formed in the casing 13. The impeller acts as a fan to carry the pulverized coal from the chamber 17 through pipes 18 to a cyclone separator C, the fine particles passing therefrom by a pipe 19 to a cyclone separator D while the heavier particles falling to the bottom of the separator C are discharged into the feed-casing 8 by means of feed-mechanism 20 driven through gearing 33 from the shaft 9' of the feed-screw 9. The air is returned by a pipe 20' to the feed-pipe 7, and by a branch 21 to the throat 10. An annular rib 23 on the upper side of the impeller prevents particles from lodging between the impeller and the casing; and to prevent suction of descending particles out between the throats 10. 11, a lip 10<1> of the throat 10 projects into the throat 11 and packing 24 is provided. The shaft 9<1> is driven through cone-pulley mechanism 30 from a shaft 29 which is driven by a belt 28 from a shaft 27 driven through worm gearing 25, 26 from the shaft 14 of the impeller. Governor mechanism 31 for controlling the supply of steam to the turbine B is operated by a belt 32 from the shaft 27. In a modification, Fig. 4, the major portion of the air is supplied by a variable-speed fan F to which the return pipe 20<1> leads and from which there is a connection to the inlet 34 in the upper part of the receiving-chamber 17. The discharge outlet 35 opens from the bottom of the chamber 17 at a point approximately below the inlet 34. In another arrangement, the apparatus is horizontally disposed, and the air inlet and the discharge outlet from: the receiving- chamber are located at the bottom and in alignment.