Modern Gasworks Practice

180 MODERN GASWORKS PRACTICE is certainly of interest owing to the unique arrangement of the plant. From the illustrations given it will be observed that the retorts are arrangecl round a circle,, the centre of which is occupied by the chimney, around which travels a radial coal feeder. Figs. 96 and 97 show a sectional elevation and plan of four beds, each of four retorts ; the sixteen. retorts being capable of an output of over half a million cubic feet of gas per twenty-four hours. The system shown is of the semi-continuous type ; but it is also designed for mtermittent working. The coal for the retorts and the coke for the producers is deposited into the measuring hoppers by means of an elevator, which may be in duplicate, through the intermediary means of a radial shoot or feeder. The feeder is of taper shape, carried on ball bearmgs or runners around the upper part of chimney, with a shoot leading to the hoppers. At the lower end of the shoot is provided a swivel extension, which can. be worked radially to enable the material to be guided into the hoppers as required. The main inclined shoot is also provided at its lower extremity with a driver’s seat on a runner carriage. This runs on a circular track over the top of the hoppers ; and all the movements for travelling over the track and working the radial shoot extension are controlled from the driver’s seat. The measuring hoppers above the retorts are capable of holding sufficient coal for a single charge on the continuous system, which can be reduced or increased at will. At the bottom of the retorts a special arrangement is provided, enabling a, measured quantity of coke to be discharged upon a slowly revolving table conveyor, which, by means of a deflecting plate. deposits the coke into a drag link or otter conveyor, which carries it to the outside hoppers and screening plant. Wlien the furnaces are clinkered, the clinker and ash.es may be removed in a similar männer by the revolving conveyor, and deflected in another direction. No coke quen.ch.ing is required, the coke being cooled sufficiently in the extension piece below the bottom retorts. This extension piece can be air-jacketed if found advisable ; the hot air being utilized for the primary or secondary-air supply. The design illustrated is for four beds of retorts. It will, however, readily be understood that a larger number of beds can be adopted, these being placed to form a regulär polygon in plan. The triangulär spaces between. the beds are utilized for the producers and regenerators—a separate one being provided for each. Vebtical Retort with Internal Heating Flue Walker and Bates 1 have introduced a vertical retort (Fig. 98) in which a central heating zone is provided. It is, of course, a fact that before'the coal around the axis of a retort can be carbonized the heat has to travel through a comparatively thick layer, although. the difficulty is usually overcome by employing a retort of moderately small breadth. (see Fig. 72). Attempts have been made to provide the retort with. a central heating flue, so that the charge is heated from within as well as from witli-out. Such retorts are, therefore, of annular construction.; but trouble in the way 1 Eng. Pat. 116,458.