The Mechanical Handling and Storing of Material

THE HANDLING OF MATERIAL BY PNEUMATIC MEANS 227 i and lead from the top of the receiver r to the lower ends of the filters f and fv and from the lid of these the two pipes k and kx lead to the air-pumps p. Below the receiver is the air trap Z, and below the two filters are two similar traps Zr The former has an outlet for the coal, and the latter for the dust, so that all the coal, large and small, is again reunited in the hopper y. The lower end of the receiver r has three inlets, o, ov and <?2, with valves for the conveying pipes v, vy, and v.2. The longest pipe v leads to the stock heap in the yard; z'3 is a branch leading to the second stock heap about 130 ft. away, and the pipes and z>2 lead straight down to the coal trucks on the siding g. The modus operandi is as follows: After two of the valves 0 are closed so that only one of the pipes v is in communication with the receiver r, a flexible pipe q, with a suction nozzle 2, is connected to the pipe, and the nozzle dipped into the coal, as shown in Fig. 313. Air is now sucked out of the filters and through the connecting pipes out of the receiver, when a mixture of air and coal enters the nozzle 5, pipes q and w, into the receiver. The air traps are of the revolv- ing type already described, and deliver, as mentioned, into the hopper y. The coal then passes through automatic weighers c and cv and, as already mentioned, into the worms s- and The dust from the filters is mixed in again in the same proportion as it is received by the nozzle, so that the coal delivered into the worms is exactly of the same quality as received from the stock heap or the railway truck. Fig. 313. Suction Nozzle of Pneumatic Coal Conveyor. The saving of labour effected by the installation was such as to cover its first cost in two years. In addition to the saving of labour there is also the advantage that the coal is emptied more completely out of the trucks, and that there is no loss through the production of dust, which was a great nuisance when hand labour was employed. The installation was built by Seek, of Dresden. For further installations see “ Coal, Coke, and Ash-Handling Plants for Boiler- Houses, Gasworks, etc.,” page 641.