The Mechanical Handling and Storing of Material

48 THE MECHANICAL HANDLING OF MATERIAL First Experiment.—The worms experimented with consisted of a paddle worm in. in diameter by 6 in. pitch, with a spindle of an external diameter of in., and a spiral worm 4 in. in diameter by 3 in. pitch, on a 1-in. spindle. Paddle worm without intermediate bearing. Spiral worm with one intermediate bearing. Speed of both, 145 revs, per minute. Paddle. Spiral. Actual capacity in bushels per minute - - 2*77 I’ll Theoretical capacity in bushels per minute - 5'545 2’297 Efficiency, per cent. - 49'95 48’324 Second Experiment.—Both worms as above, but the speed of both 300 revs. Paddle. Spiral. Actual capacity in bushels per minute - - 3’55 1'97 Theoretical capacity in bushels per minute - 11’475 4’762 Efficiency, per cent. - 30’9 41’3 Third Experiment.—Both worms reduced to half their length, so that neither had an intermediate bearing, and both running at 300 revs. Paddle. Spiral. Actual capacity in bushels per minute - - 4'44 2-61 Theoretical capacity in bushels per minute - 11'475 4’762 Efficiency, per cent. - 38’69 54’81 Power Required to Drive Worm Conveyors.—The driving power required for worm conveyors depends chiefly upon the weight of the material to be moved, and the distance which it has to be conveyed. The type of the worm, its diameter and speed, enter to a smaller degree into the calculation. It will therefore be sufficient guide to give two tables, one for light and one for heavy materials, from which the approximate horse power can be found. Table giving Approximate Horse Power Required to Drive a Worm Conveyor for Grain or Other Light Material. Tons per Hour. Length of Conveyor in Feet. 10 20 30 40 50 60 70 80 90 100 5 0-19 0-38 0-57 0-76 0-95 ri4 1-33 1-52 1-71 1-90 10 0-38 0-76 ri4 1-52 1-90 2-28 2-66 3-04 3-42 3-80 15 0-57 1-14 171 2-28 2-85 3-42 3-99 4-56 5-13 5-70 20 0'76 1-52 2-28 3-04 3-80 4’56 5-32 6-08 6-84 7-60 25 0-95 1-90 2-85 3’80 4-75 5'70 6’65 7’60 8-55 9-50 30 1-14 2-28 3-42 4-56 5-70 6’84 7-98 9-12 10-26 11-40 35 1 -33 2-66 3-99 5-32 6-65 7'98 9-31 W64 11-97 13-30 40 1-52 3-04 4-56 6-08 7-60 9-12 10-64 12-16 13-68 15-20 45 1-71 3-42 5-13 6-84 8-55 10'26 11 -97 13-68 15'39 17-10 50 1-90 3-80 5’70 7-60 9-50 11-40 13-30 15-20 17-10 19-00 For the sake of easy comparison with other conveyors, the following estimate is based on a load of 50 tons of grain per hour to be conveyed a distance of 100 ft.