The Mechanical Handling and Storing of Material

ELEVATORS FOR MATERIAL IN BULK 15 per minute is 15,900 per hour. Each bucket holds 10 lb. of wheat, so that the theoretical capacity of this elevator is 159,000 lb., or 71 tons per hour. The actual average capacity is 60 tons of wheat per hour, equal to an efficiency of 85 per cent. Speed and Cap,\city of Grain Elevators of Different Size Diameter of Pulley. Width of Pulley. Size of Buckets. Pitch of Buckets. Inches. Inches. Inches. Inches. 18 Il 9x4 17 21 13 11X4 17 24 15 13x5 18 27 17 15x5 18 30 19 17x5 18 33 21 19x6 19 36 23 21 x 6 19 42 25 23x7 20 48 26 24x8 21 60 26 24x8 21 72 26 24x8 21 Revolutions per Minute. Speed of Belt per Minute in Feet. Capacity in Tons and Bushels per Hour. 58 to 62 280 Tons. 13| Bushels. 500 52 „ 56 300 27 1,000 48 „ 52 310 40 1,500 44 „ 48 320 45 2,000 40 „ 44 330 70 2,500 38 „ 42 340 81 3,000 36 „ 40 350 95 3,500 32 „ 34 360 108 4,000 31 „ 33 400 140 5,000 31 „ 33 500 170 6,250 31 „ 33 600 203 7,500 Probably the largest grain elevator in the United Kingdom is that at the Manchester end of the Manchester Ship Canal, which has a lifting capacity of 350 tons per hour. The following table of capacities of elevators running at different speeds was given by Mr P. W. Britton in his paper on the “Transport and Storage of Grain,”1 the buckets being 12 in. apart. Size of Buckets. Number of Bushels Raised per Hour. Speed — 200 Feet per Minute. Speed--300 Feet per Minute. Speed =-500 Feet per Minute. 6 inches by 4 inches - 8 „ 5 „ - - - 10 „ „ - 12 6 „ - - - 14 „ -6 „ 20 6 „ - - - 27-5 600 850 1,300 1,600 2,275 412 900 1,275 1,950 2,400 3,412 687 1,500 2,125 3,250 4,000 5,687 If placed at any further distance apart, the capacity would diminish in direct pro- portion, so that with elevator buckets spaced 2 ft. apart, the capacity of the respective elevators would only be half that given in the table. Unless buckets are of special construction, such as those shown in Fig. 15, it is advisable to keep a space between them not less than that occupied by one bucket, so that an elevator thus fitted with ordinary buckets would be of half the capacity of that of the elevator shown in Fig. 15, provided the buckets themselves were in both cases of the same capacity. 1 Proceedings Inst. C.E., vol. cxxvi., 1895-96.