The Mechanical Handling and Storing of Material

CHAPTER XXXVII LOADING COAL INTO SHIPS OTHERWISE THAN BY TIPS Coal shippers are now largely used, where formerly only coal tips or hoists were employed, and as an introduction to this chapter we cannot do better than give the following remarks, made by Mr R. T. Smith during the discussion on the paper on the Rothesay Dock read before the Institute of Mechanical Engineers in January 1911. Mr Roger T. Smith, electrical engineer of the Great Western Railway, mentions the following five advantages of the belt conveyor over the tip for shipping coal: “ 1. That for the same capacity the initial cost of the conveyor was from one quarter to half that of a tip or a hoist. “ 2. That the load factor at which the machine worked was 80 to 90 per cent., because the maximum load was the same as the average load. “ 3. That there was a greatly reduced weight on the tower supporting the free end of the conveyor (which was adjustable) as compared with the weight of the hoist, thus lessening the cost of foundation or the cost of the jetty, if a jetty were necessary. “ 4. There was a possible saving in land for sidings, because instead of all the sidings having to come end on, as was necessary for the tip or hoist, they were much better arranged parallel with the quay. “ 5. There was an enormous reduction in the maximum demand on the power supplied.” It might, however, be mentioned that the quay space required for such loaders would prohibit their use on the Clyde and at some other ports. The economy of coal loaders on this system depends principally on the life of the belt, and as good quality cotton and rubber belts can be obtained for a guaranteed ■delivery of 1,000,000 tons of coal, the cost per ton of coal shipped is infinitesimal as far .as the wear of the band is concerned. Mr R. T. Smith also gives the following comparisons of power consumed for different systems of coal tipping and shipping Newport Hydraulic Hoist - - '164 kilowatt-hour per ton of coal raised, 46 ft. Rothesay Dock Electric Hoist - "131 ,, ,, „ » Fowey Electrically driven Conveyor '095 ,, ,, „ „ (exclusive of tipping) Before, however, proceeding to describe more fully coal shippers in which a belt conveyor forms the principal feature, we will give details of one or two other methods. Coal Loaders at the Japanese Port Miike.1—The quay of the new dock of the colliery at Miike, the property of the Mitsui Mining Co., is 460 yds. long, so “ The description and illustrations of these loaders are taken from an account by II. NoIke, in Zeitschrift des Vereines deutscher Ingenieure. 595