The Mechanical Handling and Storing of Material

THE HANDLING OF MATERIAL BY PNEUMATIC MEANS 221 at the intake end, considerable initial velocity being thus imparted to the grain, and this velocity is made use of to complete the travel of the grain to its highest point at the bend c. The diameter of the pipe gradually increases from the lower length to the bend. After the bend the pipes incline downwards to the receiver e, and this part of the transportation being thus largely effected by gravity, a saving in power is consequently obtained. The pipe boom is connected to the receiver through a socket joint and turntable d, which enables the boom to be luffed through an angle of 30°. At the same time the boom and the whole structure carrying the electric winches h, and control cabin G, can be slewed through more than half a circle, enabling a grain ship to be worked on either side, end on, or broadside on. The grain is distributed among six automatic weighers and delivered through flexible spouts m to lighters on either side of the pontoon, to the sacking-off platform n, or ashore by means of band conveyors and shoots. Owing to the elevated position of the “ canister ” in the original elevators they became rather top heavy, but the development of the down pipe idea has now led to an entirely new type of machine. The grain in the first place runs into quite a small receiving chamber e, which is placed low down on the deck of the pontoon, thus removing at once the enormous amount of top weight and every possibility of capsizing. The grain is discharged from this “canister” into the well of a bucket elevator j, and the power required to drive this is saved many times over in the economy effected through the expanded pipes. This arrangement permits of a higher weighhouse which, instead of having a divided grain hopper, as formerly, which may give a list to the machine, has only one cen'ral hopper of about half the size of that required with the old type, and cannot produce any alteration in the trim of the pontoon. To provide for the various widths as well as heights of steamers, the pipe booms are arranged to form a crane, and can be raised, lowered, or luffed, whilst the “ canister ” becomes the kingpost of the crane upon which the whole can revolve, so that the pipe can instantly be swung to port or starboard, or otherwise adapted to meet the requirements of the hold. A further improvement is effected by placing a substructure upon which the crane stands out of the centre line of the pontoon, whereby it is possible to adapt the pipes quite readily to ships varying from 40 to 90 ft. beam, since they will have a much greater reach over one side of the pontoon than over the other, whilst the reach over the end is arranged to be half way between the two. In order to avoid the enormous “stand-by” losses involved by the use of boilers, oil engines are introduced instead of steam, and these are geared to turbo-exhausters of the compound type instead of pumps, thus doing away with all valves and piston leakages. The grain is extracted from the receiver or “ canister ” E by a tipper of the Duckham type, which has been found after many years’ experience to be the most reliable and satisfactory method of extracting the grain. It differs from its predecessors in so far that the sides, ends, and rubbing surfaces are packed to avoid leakage, and for the old system of gravitation tipping a mechanical backward and forward motion so many times a minute is substituted. The rotary wheel trap or seal appears at first sight to be more scientific, but owing to the shallow depth of the pockets, even with a trap 3 ft. in diameter, their tapered form and the enormous number of blades passing per minute, they were extremely liable to break down caused by foreign matter in the grain. It will be seen that owing to the tapered form of the pockets when half full, according to their bulk capacity, they are more than three parts full by vertical measurement. This brings the top surface of the