The Mechanical Handling and Storing of Material

646 THE MECHANICAL HANDLING OE MATERIAL strand is high enough to feed three band conveyors. These deliver to the coal silos in the store, which are hopper-bottomed, and are each provided with fifteen Weiss feeders (which are illustrated in Figs. 162 and 163). These deliver the coal into three reciprocating conveyors placed in tunnels beneath the silos, the delivery ends being visible in the illustration, and also the shoots which lead the coal on to the bottom strand of the Bradley conveyor. The -coal thus taken from the store is conveyed by means of the Bradley conveyor to the top of the building, where it is fed into push plate conveyors. These in their turn fill the coal hoppers over the retorts. Coal and Coke Handling- Plant of the Bristol Gas Co.—This is a very complete installation, and illustrates the mechanical handling of coke and coal in all its stages. It is the design of Mr D. Irving, M. Inst.C.E., engineer of the Bristol Gas Co. Figs. 909 and 910 give a general plan and elevation of the installation.1 The coal is taken from the holds of vessels in the tidal river Avon, then weighed and broken to a suitable size to be further treated by the elevator and conveyor which remove it to the inclined retorts. These receive the coal without any such manual labour as would be necessary in the case of horizontal retorts. The coke, after carbonising, leaves the inclined retorts by gravity, and is conveyed by a hot coke conveyor into a yard at the opposite end to that in which the coal is received. The unloading of the coal is effected by means of a steam crane and a Hone grab. This part of the installation is capable of dealing with 30 tons of coal per hour. The grab empties its load into a hopper and weighing machine which discharge either direct into the elevator well, or, if the coal is not sufficiently small, it passes through a coal-breaker before going to the elevator. The elevator discharges at the top into a push-plate conveyor which distributes its load into overhead hoppers. The elevator and conveyor as well as the coal-breaker are driven by a gas engine of 12 H.P. The original plant was of sufficient capacity to feed an additional retort-house now erected alongside. The coal hoppers are fitted with measuring devices and shoots, to convey the coal from any of the hoppers to the retorts, which can thus be filled without any manual labour. As already stated, the hot coke is removed by a conveyor suspended from girders beneath the retort-house floor. Above it, along its entire length, are water pipes for quenching the coke as it passes on its way. Several of the conveyor covers can be removed at the point where coke has to be received, the remainder of the plates continuing undisturbed, so that the men in charge are not inconvenienced by the vapour always arising when hot coke is quenched. The plates move backward away from the retorts, so as to form a shoot for the reception of the coke, and at the same time shield the men in charge from the heat. The conveyor trough is 2 ft. 3 in. wide, and is con- structed of two channel irons with a wrought-iron plate riveted to the bottom, which is also fitted with a renewable iron strip. The return strand of the chain is carried overhead on guide pulleys. On leaving the retort-house the conveyor ascends an incline of 30° and delivers the coke, first to the screen which removes the breeze, and thence by another conveyor, partly inclined and partly level, which deposits the coke in a heap in the yard. The erection of overhead receptacles for the coke is contemplated, so that its discharge into wagons can also be effected without manual labour. The end of the coke conveyor extends so near to the river bank that the coke can be loaded by a shoot into coke barges. The conveyor at its highest end is 23 ft. above the ground, so as to command the stock heap. The coke conveyors and the screen are driven by an 8 H.P. 1 The author is indebted to Mr D. Irving for the illustration which accompanies the following description.