The Mechanical Handling and Storing of Material

CONVEYORS c._APPI IANCES IN WHICH THE TROUGH CONTAINING THE MATERIAL MOVES BODILY WITH THE MATERIAL- continued, CHAPTER VIII STEEL PLATE CONVEYORS, SLAT CONVEYORS, PICKING BELTS, AND CONTINUOUS TROUGH CONVEYORS STEEL PLATE CONVEYORS It is evident that there must be a point at which band conveyors of textile rubber and similar material can no longer be effectively used, and that point is reached when sharp and cutting substances or material has to be handled. Sometimes also a firmer base than that afforded by a band conveyor is desirable. In such cases it is usual to employ endless bands, so to speak, composed of a series of iron plates connected to suitable chains running beneath the plates. Conveyors of this type are used in the same manner as band conveyors of rubbsr or cotton. Of course the steel plate conveyor is a more cumbrous appliance, travels at a much lower speed, and has a much more restricted field of usefulness than a rubber or textile band conveyor. The segments of steel plate conveyors are attached to chains either of malleable, cast, or wrought iron. The former are more frequently used because they can more readily be shaped, with suitable attachments, for any special work, and all kinds of carrying plates can easily be fitted to them. Ordinary Ewart-type chains are not much used, because they wear rapidly, and are very liable to breakages when used for such heavy work; and though broken parts can no doubt be readily replaced, yet an accident to a conveyor must cause stoppage and delays. The form of conveyor more generally used is one in which the links are of malleable cast iron and are joined together by hardened steel pins, with renewable wearing parts such as made by the Chain Belt Engineering Co. Where such conveyors are required for extra heavy and especially rough work, or where stoppages would be most detrimental, it is usual to use steel chains, the links of which may either be short after the style of the Gall chain, or consist of long forged links of the same length as the width of the plates. This type of conveyor generally delivers only at the driving terminal; but should intermediate delivery be required, a delivery scraper is fixed across the band at an angle of about 45°, to scrape the whole or part of the feed of the band into a shoot, or. on to a stock heap. If the intermediate delivery is not confined to one or more fixed points, and if it be desirable that delivery should take place at any point in the length of th’e conveyor, a scraper is mounted obliquely on a suitable carriage which can be moved into any position for the purpose of intermediate delivery. Such an arrangement is in use at the coke yard of the Southall Gasworks. 98