Modernization of a Coal-Discharging Depot

The paper describes the modernization of a coal-discharging depot originally equipped with hydraulic transporters. The steps taken to enable the jetty to withstand a greatly increased loading are given, and the crane rail girders of special fabricated type are described.

The relative merits of various types of unloader are discussed, and the reasons given for adopting electric luffing cranes. The principal features of the special electric cranes installed are described, together with the reasons for adopting certain unusual features, and the provisions made for ease of maintenance and interchangeability of mechanical parts. The system of electrical control adopted is described. The design and operation of grabbing cranes is compared with that of normal cargo cranes.

The question of load balancing for cranes is considered and calculations given of speed, acceleration and power consumption for similar cranes without any balancing, and with varying degrees of balancing of the load. The effect of varying height of lift on power consumption is shown graphically. The importance of low inertia of the moving parts of high-speed cranes is emphasized, together with comments on the methods which can be adopted to achieve this end.

The design of crane ropes and sheaves and the effect of the reverse bending of crane ropes is discussed briefly, and figures are given of rope life with various designs of grabbing cranes. The importance of high rope-diameter/sheave-diameter ratio is stressed.

A brief description is given of a special form of crane weighgear used for the first time on the new cranes at the depot.

The question of grab design is discussed briefly, with particular reference to coal handling, and results are given of different designs of grabs dealing with various classes of coal under normal operating conditions.

An outline is given of the method of erecting the new cranes without interrupting the working of the depot.