Modern Gasworks Practice

336 MODERN GASWOBKS PRACTICE vessels. Moreover, once set in motion the conveyor is more or less automatic in its action, and in some cases requires no driver in constant attendance, as does the telpher. Unlike conveyors, the telpher does not require a straight road, wliile differences in level do not affect it. Its main aclvantage, besides speed, is that being overhead it occupies no ground space in the retort house or other buildings, where freedom from congestion is essential. The Cost of Conveyors In order to compare the relative costs of conveying machinery it is necessary to base figures on equivalent capacities for the different types in question. Generally, costs are based on the outlay per foot run. Thus the total length of the installation has some influence on this item. The following figures refer to costs prevailing at the time of publication. While, tlierefore, they give a useful indicatioii of the comparative costs of various systems, it must be remembered that they are liable to be influenced at any time by the prevailing uncertainty in the martets for labour and materials. Comparative Costs of Various Systems of Handling (1) Electric Telphers— £ -s, d. (a) Overhead track, structure, and trolley wire. Height of track, 45 to 50 feet . . . . . . . 12 10 0 per foot run. (b) Telpher machine, complete with motors, lifting capacity, 35 cwt. at 70 feet per minute ______________________.... 1,500 0 0 (c) Skips for coke, 1 ton capacity (each) . . . . 85 0 0 (2) De Brouwer Hot-Coke Conveyor . . . . . . 12 0 0 per foot run. (N.B.—Yard conveyors supported at a considerable height above the ground may entail an outlay of £18 per foot run, which includes supports.) (3) Gravity-Bücket Conveyors— («. ) Capacity 25 tons per hour (b) „ 30 „ (c) „ 50 „ (d) „ 80 „ (e) „ 100 „ „ £ s. d. 7 0 0 8 0 0 9 0 0 10 10 0 12 5 0 to £ 8 9 10 12 14 5. d. 0 0 per foot run. 0 0 0 0 „ 5 0 0 0 (N.B.—The above prices, for an average length of 250 feet, include the chain, buckets, wheel curves, track rail, fillers, vertical guides, etc., but not driving motor.) (4) Push-Plate Conveyors for coal— £ -s. d. £ s. d. (a) Capacity 20 tons per hour . . . . 10 10 0 to 12 5 0 per foot run (b) „ 25-30 „ „ . . . . 12 5 0 „ 13 0 0 (c) „ 35-40 „ „ . . . . 13 0 0 „ 14 0 0 (</ ) „ 50 „ „ . . . . 14 0 0 „ 15 0 0 „ (Conveyor complete, with exception of driving motor.) (5) Tipping-Tray Conveyors for coal— (a) Capacity 50 tons per hour . (6) „ 80 „ (c) „ 100 „ „ (6) Bücket Elevators— (a) Capacity 25-30 tons per hour (b) „ 45 (c) „ 55 £ s. d. £ s. d. 22 0 0 to 24 0 0 per foot run. 24 0 0 „ 25 0 0 25 0 0 ,, 28 0 0 £ s. d. £ s. d. 16 0 0 to 17 0 0 psr foot run 18 0 0 „ 19 0 0 21 0 0 „ 22 10 0