The Mechanical Handling and Storing of Material

WORM OR ARCHIMEDEAN SCREW CONVEYORS 57 The driving pulley is made in halves, with a square opening to fit the square tube, and this can be attached at any point in the length of the conveyor most conveniently situated in relation to the driving power. Conveyors of this design have been built and are successfully at work in lengths up to 250 ft. Fig. 60 shows such a conveyor in a cement works. As this tube conveyor is very rigid, it can also be used for transmitting a limited amount of power, so that at the extreme end, or in any desired position, power may be taken off by fixing a pulley, similar to the main driving pulley, concentrically on to the tube for driving small auxiliary conveyors or even elevators. This is sometimes of great convenience. Fig. 60. Suess Conveyor, 250 ft. long, Conveying Fine Cement at Witkowitz, Austria. Fig. 61 represents a perspective view and part section of such a conveyor, and Figs. 62 and 63 show cross and longitudinal sections of the same. The illustrations show a wooden tube with metal channels, d represents the oblique blades, e e1 e2 e3 show the longitudinal channels in the four corners as described above. The spaces ff ■can be covered over with sheet iron. is the filling apparatus which revolves with the tube, and has lifters which scoop up the material fed into the fixed inlet i and deliver it into the conveyor tube, k and kx show the slope at which the material is delivered into the tube, b are the ring supports to be used when further supports are desirable in addition to, or instead of, the flange coupling supports. These ring supports b are also employed in such positions where at times a portion of the conveyor has to be thrown ■out of work. For instance, if a conveyor of 100 ft. total length has to deliver for a