The Mechanical Handling and Storing of Material

CHAPTER XII THE HANDLING OF HOT COKE IN GASWORKS The substitution of machinery for manual labour in the conveyance and handling of hot coke in gasworks, coke-oven installations, and elsewhere, presents many special diffi- culties, owing to the hard and friable nature of the material, and its more or less red-hot condition. Its hardness gives rise to severe wear and tear of the conveyor trough or band, and any roughness in handling causes considerable loss by the production of coke dust or “ breeze,” which is not only worthless, but, moreover, enters the joints of chains and other moving parts, and grinds them away, even when the coke is being quenched with water, as in that case the water often washes the small gritty particles into the wearing parts. The sudden changes of temperature to which the conveyor is subjected, also, produce expansion and contraction, causing warping and buckling of the conveyor or its parts. Very few attempts have been made as yet to employ mechanical conveyors in connection with coke ovens. The Author, therefore, proposes to deal more particularly with conveyors suitable for use in gasworks, as he believes that larger conveyors of similar design may be eventually adopted in coke-oven installations, which play such a prominent part in the iron and steel industry. From an economical standpoint, the substitution of machinery for manual labour in handling coke does not present the same advantages as in the case of coal, principally because the wear and tear is so much greater, necessitating much heavier and more costly machinery, so that mechanical coke-conveying plants can only be recommended for large establishments. The hand labour involved in quenching, carrying, and stacking coke has been known to cost Is. per ton, but under the most favourable circumstances a man can remove hot coke from the retort house of a gasworks to the- coke heap at the rate of about 15 tons per day, so that the cost for hand labour in such a case would be about 3d. per ton of coke handled. To this would have to be added the cost of repairs and renewal, interest on capital outlay, etc., which would not exceed Id. per ton of coke dealt with. The most favourable total cost for hand labour might therefore be taken at 4d. per ton. According to the calculations of the late Mr W. R. Chester, M.Inst.C.E., who had several years’ experience with push-plate and metal-band conveyors for handling hot coke, the average cost of repairs and renewals for a conveyor 100 ft. in length was l|d. per ton of coke handled. The cost of such a conveyor would be, approximately, ^G00, and as it would be capable of conveying 30,000 tons of coke per annum, 5 per cent, interest on the capital outlay would represent about |d. per ton of coke conveyed. The driving power for such a conveyor would depend very much upon its state of repair, but allowing |d. per ton it may be assumed that the total cost, including driving power, would not exceed 2d. per ton of coke handled. The substitution of machinery for hand labour thus appears to have effected a saving of 2d. per ton, and it should be taken into consideration that in conveyors of the most modern type the wear and tear and the driving power consumed would be less than in those of the Nottingham Gasworks, on which Mr Chester based his calculations. 144