Modern Gasworks Practice

290 MODERN GASWORKS PRACTICE The earlier machines were suspended from an overhead carriage and traversed along by hånd, but as this was a somewhat slow process the later machines were arranged in a travellmg carriage or frame, and were driven by power. With projecting chargers of this type some form of obstruction or stop is required at the further end of the retort to prevent the coal piling up on the cool mouth-piece. An ordinary piece of plate with. a supporting rod at the back is generally used for the purpose. It is as well to remember, however, that the vertical stop originally employed fréquently accounted for a small portion of coal remaining un-carbonized at the end of the distillation period, and it is preferable to make use of the slanting stop as seen in Fig. 207. A more recent type of stop is shown in Fig. 208. The following are the more interesting points connected with the De Brouwer machine :— Large pulley : Diameter, 1 metre (39'3 inches). Width on face, 15 inches. Width of groove, 8 inches. Depth of groove, 3f inches. Average speed of pulley, 220 revolutions per minute. Average speed of coal band, 2,300 feet per minute. Power required, 10 to 15 amperes at 220 volts. The Jenkins-De Brouwer Pusher This machine has a strongly braced framework of Steel cha.nnp.1s and angles, forming a travelling carriage, and is fitted with. wheels for running along rails in front of the retort beuch, preceding the De Brouwer charger. An electric motor and gearing box is fixed on the main channels of the frame, on the left-hand side, for hoist-ing the pusher ram to snit the various tiers of retorts and also for propelling the machine along the rails. The motor is of 7J b.h.p., entirely enclosed, provided. with. end covers, dirt and dust proof, and connected by a suitable coupling to the first motion sh.aft in the gearing box. The gearing box is fitted with. a worm and worm wheel and spur gearing, also a clutch. for connecting either the hoisting or propelling gear to the motor. One spur pinion in the gearing box gears with a spur wheel on one of the axles of the machine, and th.e worm wheels shaft carries a chain drum round which the hoisting cliains work. These chains pass upwards from the drum, over pulleys on the machine frame, down again and round pulleys on the hanging frame carrying the telescopic ram, and back to a point near the top of the frame, where they are anchored. The telescopic ram is in. three parts, the first or inner length being formed of a strong mild-steel bar cut out of the solid and having drilled holes for the driving sprocket teeth. and a plate end. The plate end carries a hood or scoop at the top to hold the coke and keep it from crushing up. This inner bar slides within the second length. Inside the front end of the second length. is fixed a suitable stop which. fits into a groove on the top side of the first length, so as to fix the length. of stroke of the first bar and to ensure it having a rigid bearing wit.hin the second length. when