THE MECHANICAL HANDLING OF MATERIALS 319
(a) Conveyance of coke direct from the retorts to a suitable storage place.
(b) Conveyance of unquenched coke direct to water-gas generators.
(c) Treatment in grading, screening, washing and loading or bagging plant.
The methods employed at the present time for efEecting this series of operations vary to some considerable extent, and in nearly all cases it is essential to introduce plant which has the functions of the elevator and conveyor combined. Put briefly, the plant may be classified under two main headings—
(d) Apparates utilizing the ordinary principle of conveying, e.g. drag-bar, travelling-tray, or gravity-bucket conveyors.
(e) Transporter systems, e.g. electric telphers, or travelling skips.
Fig. 233.—West’s Hot-Cokb Conveyoe. Original Type.
Each method has its particular advantageg, and the question as to which shall be adopted must be decided entirely by local conditions and requirements. In many cases a combination of the two types is the ideal arrangement, a conveyor being used inside the retort house and a telpher outside in the coke yard.
One of the earliest systems introduced for dealing with hot coke was that which was installed more than twenty years ago at the Gaytliorn station of the Manchester Corporation Gas Department. The problem to be solved was the immediate removal from in front of each retort, as it was discharged, of 4| cwt. of coke falling from the retort in 15 seconds. It was necessary to provide a conveyor of sufficient capacity, and travelling at such a speed as to convey the coke out of the way of the retort