Modern Gasworks Practice

THE MECHANICAL HANDLING OF MATERIALS 831 speed of 400 feet to 750 feet a mi nute may be attained. This is 10 to 20 times thc speed of the ordinary coke conveyor. The most satisfactory arrangement of the track is to suspend it from overhead steel lattice girders, having spåns of from 60 feet to 100 feet, supported at the end by steel tresties. This arrangement gives fewest obstructions in the yard, and fewer tresties to Fia. 244.— Junction Line Ofen. Fig. 245.—Main Line Opbn. suffer from the corrosive action of the coke mass surrounding them. Where, however, uprights are likely to be buried in coke they should be concreted up. The telpher collects its current from an overhead trolly-wire attached to insulators fixed above the track. A single wire is quite suitable where direct current generated at the works