702 THE COLLIERY GUARDIAN. April 1, 1915. AUTOMATIC COAL-HANDLING PLANT. A question which indubitably must invite attention under conditions in which the necessity for “ speeding- up ” is accompanied by a shortage of labour is the system of coal and ash handling. The first cost of a coal con- veying plant is not, all things considered, a seriously expensive item, while the cost of working each conveyor, including interest on capital expenditure, attendance, oil, motive power, depreciation, and repairs, should not work out at more than a fraction of a penny per ton. Excellent conveyors are now made which. possess a flexibility of application enabling them to be adapted to any individual and often awkward cases, and the general construction of a first-class conveyor admits of the interchangeability of its parts, enabling the capacity to be diminished or increased according to require- ments. It is cheap in application, simple in working, and durable in practice, while the driving power can be taken from any convenient means at hand. An instance of a coal handling plant presenting some features of interest is that installed at the Southend-on- Sea Corporation Electricity Works. The recent exten- sion carried out under Mr. Robert Birkett, the borough .»■ Fig. 1.—View of Chain Conveyor. ‘‘•y. Fig. 3.—View of Electric Transporter at Wigan. ground level and outside the boiler house. The bottom end of the bucket elevator is carried below the hopper, and the coal flows into the buckets by gravity through a Bennis rotary safety feeder, which ensures a regular supply to the buckets, and, at the same time, prevents any sudden rush which would choke the buckets and jam the elevator. The elevator itself is about 70 ft. long, and will raise the coal at the rate of 20 tons an hour. It is driven by an electric motor situated above the first bunker. The framework of the elevator is of substantial construction, so that no intermediate supports are required between the top and bottom. The full and empty buckets are carried in separate trunks, and the casings are practically dustproof. The whole of the gearing, chutes, etc., is carried by the elevator frame- work, avoiding all external supports or bearings, and making the whole a self-contained and neat machine, occupying little room. : ' I ; - I ■ ,'4- 5 Fig. 2.—View of Elevator at Southend. bottoms. A number of openings are made at the bottom of each bin, and each opening is provided with an outlet chute and radial cut-off valve. The cut-off valves are operated by chains from the firing floor. A swing chute is suspended beneath each outlet for guiding coal from the bunkers to the stoker hoppers. These chutes are made to swing back out of the way when boiler tubes are ‘being cleaned or renewed. The bunkers.have a total length of about 106 ft. Their vertical sides are 11 ft. deep, and their top is about 39 ft. above the firing floor level. They are carried on 12 stanchions formed out of rolled steel joists, 27 ft. long, resting on concrete pillars built level with the firing floor. A superstructure is built on top of the bunkers to Carry the conveyor, which works in a chamber carried the full length of the bunkers. The sides and roof of the chamber are formed with corrugated sheet, in which continuous windows are set in each side. Access is obtained to the conveyor chamber by a ladder on the elevator frame. The extreme height from the bottom of the stanchions to the top of the superstructure is about 56 ft. In another case, that of the Wigan Corporation Elec- tricity Works, the coal is unloaded from barges at a point about 80 ft. away from the boiler house. It became-necessary in the interests of economy to provide some effective mechanical means for conveying the coal from the canal to the boiler house, and the scheme recently put into operation has provided results eminently satisfactory to the borough electrical engineer, Mr. J. Slevin. The coal is trimmed by hand from barges into skips, which are hooked on to a travelling electric transporter running along an overhead track, extending between the boiler house and the canal. The transporter raises the loaded skips, and carries them along the overhead track, after which they are emptied into a receiving hopper placed above an automatic weighing machine. The weight of the coal is auto- matically recorded, and it passes on into a second hopper with two outlets. The overhead coal bunkers are in two separate sections, in line with each other, and about 100 ft. apart; the, coal is conveyed to these bunkers by two Bennis U-link steel chain conveyors, described above. These conveyors receive the Coal through the two openings in the hopper before mentioned, and are so arranged that both conveyors can run simultaneously or independently of each other, as may be desired. The conveyors are inclined for the first portion of their length, in order to raise the coal to the level of the top of the bunkers. The remaining portion of the con- veyor is horizontal, and passes over the top of the bunkers. Openings provided with cut-off slides are placed at intervals in the conveyor, through which the coal can be dumped at any desired point. Each con- veyor is driven through suitable reduction gear by a separate motor, independently of the other, and has a capacity of about 20 tons of coal per hour. A gangway runs along at one side, giving easy access to the various pants of the plant. The electric transporter consists of a travelling hoist, Fig. 5.—Automatic Weighing Machine and Conveyors. Jill electrical engineer, provided an opportunity for the installation of a coal handling plant supplied by Messrs. Ed. Bennis and Company limited, of Little Hulton, Bolton, which was built in accordance with one of several schemes submitted by Messrs. Bennis and other engineering firms. The plant at present feeds four boilers, but has been arranged to cover an additional boiler w’hen required. The gear has also been designed so that if the older boilers are replaced in the future, no structural alterations will be necessary in the coal handling plant. The arrangement consists of a series of overhead storage bunkers, of a total capacity of 500 tons of coal; a bucket elevator raising the coal from a dump- ing hopper; and a horizontal conveyor which distributes the coal to the bunkers. One of the most interesting features of the new installation is that, in order to obtain room.for the over- head bunkers, it has been necessary to cut away a con- siderable portion of the original boiler house roof. It was not possible to place these bunkers outside the limits of this roof, as a car shed adjoins the boiler house, and its roof rests on the party wall separating the two build- ings. Originally the boiler house roof rested on this same wall. It was necessary to cut off the ends of eight of the roof principals, and take the weight on the inner side of the bunker structure. Coal is brought to the station in (‘arts, and is dumped into the receiving hopper, which is excavated below Fig. 4.—Plan and Section of Bennis U-link Chain Conveyor. At the top end the elevator delivers the coal through a chute.to a Bennis U-link steel chain conveyor. This consists of a series of mild steel bars pressed into the form of a U, and riveted together to form an endless chain. The lower part of the chain moves along a rectangular trough, and carries the coal with it. Open, ings are placed in the bottom of the trough at desired intervals, and the coal falls through them into the bunkers beneath. The conveyor is driven through gear- ing from an electric motor situated near its right hand end. A gangway alongside the conveyor allows of access to all parts of it, and to the elevator. The bunkers are built up of mild steel plates, and sections riveted together to form a service of rectangular bins with hopper having separate motions for lifting and travelling. Each motion is operated by a separate motor. All the operations of hoisting, travelling, and lowering are under the direct control of a single attendant, who travels with the hoist. The transporter runs on a track which is formed by the base flanges of an “ H ” section steel joist. The wear is taken by replaceable mild steel flats, which are fastened to. the lower flanges of the joist by means of counter-sunk rivets. The joist is supported on a structure consisting of lattice girders carried on latticed trestle supports, two of these columns being reinforced by ferro-concrete. The clear height of the track above the ground level is 33 ft. 9 in. The structure is built in three spans, the longest of which is about 48 ft. The bunkers are rectangular in shape, each being 7 ft. 6 in. wide by 7 ft. 9 in. high by 80 ft. long, and are constructed with a framework formed of rolled steel sections, with the intervening spaces filled in with panels of brickwork and concrete, the whole being braced together to form a rigid structure. Small hoppers are built in the bunker floor, above each chain grate stoker, and the coal passes by gravity from the bunkers to the stokers through a series of chutes. Each chute is arranged to swing back to: admit of access to the boiler tubes. The bunkers are supported on rolled steel .joists, built into the boiler house wall at one end, and supported on stanchions at the other end.