(b) Troughed Belt Conveyor: In this conveyor, comparatively w flat belt is supported on troughed carrying rollers or shaped supporting surface so that the two edges of the active side of the belt are elevated from the middle part to form a trough. This provides a greater carrying capacity than a flat belt f equal width for conveying bulk materials or those materials which would slide off flat belts. These conveyors are used in handling bulk ma terials of different classes. The return side of the belt is generally kept flat supported on cylindrical rollers. from one The troughed conveyors which are used within a pant for moving conveyors. These are point to another. are generally termed as "normal" or "transfer" comparatively of shorter lengths, and path of movements are in straight line in a horizontal or an inclined plane, The stresses in the belts being within limits of cotton fabric belts. However, troughed belt conveyors are often used for transportation of bulk materials over nation of in- long distances, by means of a series of conve rs, over paths that are clines. declines and horizontal sections. following the natural contours of the ground. These conveyors. There is no clear demarcation between a are generally termed "long-centre" normal or long-centre conveyor. Lo center conveyors are those where belt lension high warranting use of high tension quality belts with less belt stretch, and low deederation drive. By using a number of conveyors in series. it through gradu aring controls change the direction of materials movement at the junction of two conveyors, is possible called transfer terminal'' Long-centre conveyo e used for jobs like: transporation of the output of mines to loading the processing plants, (ii) materials from shipping ports to the storage/transport sites, (iii) materials from outdoor storage yards to inside plants, (iv) movement of materials between plants etc (c) Closed Belt Conveyor: In a closed belt conveyor, the specially fabricated belt, after being loaded with the material, can be wrapped completely around the load. It essentially forms a closed tube moving along with the material The advantages of a closed belt conveyor are: (i) it can handle fragile materials safely and without breaking by reducing interparticle collision, (ii) it can handle fine bulk materials without being swept by air (however it is not really air tight at loading and unloading points). (iii) ability to handle corrosive an reac e materials without contamination and (ii) the tubed belt can travel around bends in more than one plane and hence versatile in layout.